JP7736632B2 - Railway vehicle battery system and control method thereof - Google Patents

Description

The present invention relates to a railway vehicle battery system and its control method.

In recent years, advances in lithium-ion battery technology have led to the spread of railway vehicles (hereinafter also referred to as "vehicles") that use batteries as their energy source, such as hybrid diesel railcars and battery-powered electric trains. The batteries used to run such vehicles are used as an appropriately high-voltage, high-capacity energy source by forming battery packs consisting of single cells (hereinafter referred to as "battery cells" or "batteries") connected in series and parallel. If there is a voltage difference between multiple batteries connected in parallel, harmful cross currents will occur, and measures must be taken to prevent this. The following Patent Documents 1 to 5, for example, are known as technologies related to this cross current.

Patent Document 1 discloses a method for connecting batteries that temporarily inserts a resistor in the path of the cross current to suppress the cross current. In this method, if there is a voltage difference between the battery groups before they are connected in parallel, the battery groups are connected in parallel via an additional resistor by operating a contactor, suppressing the cross current value. After the voltages between the battery groups are equalized by the cross current, the resistor is separated and the battery is connected to an external load.

Patent Document 2 discloses a power storage device and battery control method in which circuit breakers are provided above and below all series-connected groups, and by connecting batteries in order from lowest voltage to highest, the number of batteries that can be connected in parallel is increased while leveling out the battery voltage.

In addition, in the technology of Patent Document 2, in order to prevent the cross current value from suddenly becoming large when batteries are connected in parallel without using a resistor, the parallel connection of the storage batteries with lower voltages is started first, thereby suppressing the cross current. In addition to this reason, the technology also aims to prevent electric shock, and the number of contactors is increased to ensure reliable disconnection by arranging contactors on both the positive and negative sides of each storage battery group.

Patent Document 3 discloses a power storage system and connection method that determines whether the power storage system is in a charging mode, a discharging mode, a connected mode in which the power storage system is connected to a power grid, or an independent mode in which the connection is cut off, and enables multiple power storage devices to be effectively connected to a power conversion device.

The technology of Patent Document 3 controls charging and discharging based on information that is distinguished between charging and discharging operations. In charging operations, this technology sequentially starts charging from a group of low-voltage batteries , and connects batteries in parallel in order of voltage matching that of the group of open-circuit batteries . In discharging operations, this technology sequentially starts discharging from a group of high-voltage batteries , and connects batteries in parallel in order of voltage matching that of the group of open-circuit batteries .

Patent document 4 discloses a battery monitoring device that provides one open/close switch on the positive side and three open/close switches on the negative side for multiple battery modules, and can sometimes determine abnormalities using a common threshold value and individually isolate modules that are experiencing problems such as abnormalities.

The battery monitoring device of Patent Document 4 has a circuit configuration including a contactor for disconnecting the storage battery groups arranged on the N side of each series group in the battery pack, and a main relay for disconnecting the battery pack arranged on the opposite P side after parallel connection. With this circuit configuration, each storage battery group in the battery pack can be individually disconnected by breaking the N side contactor, and all storage battery groups in the battery pack can be simultaneously disconnected by breaking the P side contactor.

Patent Document 5 discloses a monitoring and control device, storage battery system, and method for monitoring and controlling multiple battery units and the PCS (Power Conditioning Subsystem) that charges and discharges them, including mathematical formulas that describe cross currents.

JP 2013-240142 A Japanese Patent Application Laid-Open No. 2018-120663 Japanese Patent Application Laid-Open No. 2021-052559 JP 2015-197359 A Japanese Patent Application Laid-Open No. 2021-125952

However, the battery pack in Patent Document 1 requires a resistor that is connected only when the battery is connected in parallel within the battery system, and multiple contactors that either connect through the resistor or separate the resistors, resulting in a larger system.

Furthermore, in the energy storage device of Patent Document 2, in a circuit that connects the batteries directly in parallel without using a resistor, if the voltages of the battery groups differ significantly, simply changing the order cannot suppress the cross current below a threshold, and there are cases in which the battery groups cannot be connected in parallel without external charging and discharging.

Furthermore, the battery system of Patent Document 3 has a circuit configuration that takes into consideration a case where battery groups are connected in parallel in one layer within a single system. Therefore, Patent Document 3 does not disclose a circuit configuration in which battery groups are further connected in parallel within a battery box that is connected in parallel, such as in a railway battery system.

Furthermore, the battery monitoring device in Patent Document 4 is an invention whose primary purpose is to ensure reliable shutoff, and does not address how to close the contactors when a cross current occurs, or in particular the order in which to reclose them. Furthermore, Patent Document 4 only discusses a single battery pack and does not consider connections between multiple battery packs. Furthermore, Patent Document 5 does not disclose a railway vehicle battery storage system that minimizes the number of contactors required to suppress cross current.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a railway vehicle battery system that minimizes the number of contactors required to suppress cross current between battery groups or battery boxes.

The present invention, which solves the above-mentioned problems, provides a railway vehicle battery system comprising one or more battery boxes containing multiple battery groups connected in parallel, a parallelization control unit that maintains each of the multiple battery groups at an equal voltage, and group switchgears for each group that are disposed in the battery boxes and connected in series to at least one pole of each battery group, in which an assembled battery is formed. Each group switchgear has one box switchgear connected in series to a connection point where the multiple battery groups are connected in parallel, with a pole opposite to that of the series-connected pole, and the parallelization control unit connects the battery groups in the battery boxes in parallel by closing each group switchgear, and connects the battery boxes in parallel by closing each group switchgear and the box open/close device.

According to the present invention, it is possible to provide a railway vehicle battery system that minimizes the number of contactors required to suppress cross current between battery groups or battery boxes.

FIG. 1 is a circuit diagram for explaining the concept of cross current. 1 is a diagram showing the system configuration of a battery electric railcar drive system (hereinafter also referred to as "this battery electric railcar drive system") 1A according to a first embodiment of the present invention. 1 is a diagram showing the system configuration of a hybrid diesel railcar drive system (hereinafter also referred to as "this hybrid drive system") 1B according to a first embodiment of the present invention. 1 is a diagram showing a circuit configuration of a railway vehicle battery system (hereinafter referred to as "the battery system") 100 according to a first embodiment of the present invention. 3 is a block diagram showing a parallel control system 200 in the battery electric railcar traction system 1A of FIG. 2. 6 is a flowchart 300 showing the processing procedure of the parallelization control unit 210 of FIG. 5. 4 is a flowchart 400 showing a control procedure for running cut-in in the battery electric railcar drive system 1A of FIG. 2. 7 is a time-series switch opening/closing table and graph showing the cruising range and acceleration force during charging under the parallel control of FIGS. 5 and 6 . 7 is a time-series switch opening/closing table and graph showing the cruising range and acceleration force during discharge under the parallel control of FIGS. 5 and 6 . FIG. 10 is a circuit diagram showing a battery box 101a according to a modified example a. FIG. 10 is a circuit diagram showing a battery box 101b according to a modified example b. FIG. 10 is a circuit diagram showing a battery box 101c according to a modified example c. FIG. 10 is a circuit diagram showing a battery box 101d according to a modified example d. 5 is a table comparing the effects of battery boxes 101a, 101b, 101c, and 101d of modified examples a to d with the battery box 101 of FIG. 4. FIG. 10 is a diagram showing the configuration of a multi-pole contactor 116 according to a second embodiment of the present invention. FIG. 10 is a circuit diagram of a railway vehicle battery system 199 according to a second embodiment of the present invention. FIG. 17 is a block diagram showing a parallel control system 299 applied to the battery storage system 199 of FIG. 16. 17 is a flowchart 300 showing the first half of the procedure of parallel control by the battery system 199 of FIG. 16. 19 is a flowchart 300 showing the latter half of the procedure of the parallelization control of FIG. 18. 17 is a table comparing the effects of battery boxes 101a, 101b, 101c, and 101d of modified examples a to d with the battery box 101 of FIG. 16.

First, cross current will be explained using FIG. 1 and the following equation (1). Then, using FIGS. 2 to 20, the present battery electric train drive system 1A (FIG. 2), the present hybrid drive system 1B (FIG. 3), and the present battery systems 100, 199 (FIGS. 2 to 4, 16) mounted thereon will be explained. As will be described later using FIG. 4 and other figures, the present battery systems 100, 199 minimize the number of contactors 112, 113 required to suppress cross current between battery groups 111 or between battery boxes 101. Note that, unless there is a need to particularly distinguish the present battery system 199 of Example 2, they will be collectively referred to as the present battery system 100.

The battery group 111 referred to here is an assembled battery formed by connecting an appropriate number of battery cells in series to obtain the voltage required for the application, with service connectors 114 provided on both poles. The battery box 101 is a box of a size that is convenient for installation and maintenance within the overall assembled battery configuration according to the application, and includes one or more battery groups 111. Since the present battery system 100 is primarily composed of assembled batteries, the assembled battery referred to here may be considered to be the same as the present battery system 100.

Figure 1 is a circuit diagram to explain the concept of cross current. Cross current is the current that flows in a parallel circuit when there is a voltage difference between batteries connected in parallel. As shown in Figure 1, consider battery 1, which generates voltage V1 across resistor R1, and battery 2, which generates voltage V2 across resistor R2, connected in parallel via external resistor RPar and switch S. The cross current Icro in equation (1) below reaches its maximum value the moment switch S is closed.

Note that Icro is positive for charging. Cross current flows in the charging direction in the low-voltage battery and in the discharging direction in the high-voltage battery. Cross current is generally at its maximum value at the moment of connection, and gradually decays until the open-circuit voltage values (which depend on the charging rate) between the parallel-connected batteries become the same.

If the cross current is large, it may damage the batteries themselves as well as the contactors, fuses, and conductors connected to them. The multiple battery boxes 101 in the battery system 100 and the battery groups 111 therein are all connected in parallel and have the same voltage (e.g., 1600 V). Therefore, no large cross current flows when the contactors 112, 113 are opened and closed when the vehicle system is turned on and off. The vehicle system here refers to the battery electric train traction system 1A, the battery system 100, and the control system that controls the operating state of the entire vehicle in accordance with operating commands higher than the control hierarchy of the vehicle control device 13 (Figure 5).

On the other hand, there are two cases in which the voltage of at least one of the battery group 111 and the battery box 101 becomes different from the voltage of the rest of the system. The first case occurs when a battery module in the battery system 100 is partially replaced. Since the number of years of use of a railway vehicle is longer than the lifespan of the storage batteries, partial battery replacement is often required when battery deterioration progresses locally. In this case, the voltages of the newly replaced batteries and the worn-out batteries will not match, and adjustment will be required.

Second, even if a battery group 111 including a battery with an abnormality is disconnected from the battery-powered electric train traction system 1A, the remaining battery groups 111 can still be used to some extent, so there is a case where the charge rate fluctuates due to charging and discharging. When battery groups 111 with significantly different voltages are reconnected in parallel in this way, it is necessary to take measures to suppress cross current for safety reasons.

Figure 2 shows the system configuration of the battery electric train drive system 1A. A battery electric train equipped with the battery electric train drive system 1A is a railway vehicle equipped with a chargeable and dischargeable battery system 100 as its driving energy source. In electrified sections, the train receives power from overhead lines, which is used for driving energy and charges the battery system, and in non-electrified sections, the train runs using the battery as its energy source.

In Figure 2, solid lines indicate power transmission paths, double lines indicate torque transmission paths, and dashed lines indicate transmission paths for information such as control signals and sensor values. This battery-powered electric train drive system 1A functions to run on power from overhead lines in electrified sections and charge the battery, and to use the battery's power in non-electrified sections. First, the configuration of each device in this battery-powered electric train drive system 1A will be explained.

The battery electric train drive system 1A is composed of a pantograph 2 that connects it to the overhead line, a converter 5 that converts overhead line power into the required DC power, a motor inverter 6 that converts the DC power into AC power, a motor 7 that drives the railway vehicle, a reducer 8 that reduces the output of the motor 7 and transmits it to the wheelset 9, an auxiliary inverter unit 10, auxiliary equipment 11 used for servicing the vehicle's lighting, air conditioning, etc., the battery system 100, a driver's cab 12 that has a display and generates driving commands in response to the driver's notch operation, and a vehicle control device 13 that generates control commands for the converter 5, the motor inverter 6, and the auxiliary inverter 10 based on the driving commands sent from the driver's cab 12 and the status of the battery system 100.

The pantograph 2 is an electrical switch that moves up and down, and when it rises and comes into contact with the overhead line 14, it supplies DC or AC power from the overhead line 14 to the converter 4. When the pantograph 2 is in contact with the overhead line 14, the battery-powered train runs on power from the overhead line and charges the battery. On the other hand, when the pantograph 2 is not in contact with the overhead line 14, the battery-powered train uses the power from the battery for motive power, etc.

Converter 4 receives DC or AC power output from pantograph 2, converts it into DC power corresponding to the commanded amount of power, and outputs it. Motor inverter 6 converts the DC power supplied via converter 5 into three-phase AC power to drive motor 7. Motor 7 receives the three-phase AC power output by motor inverter 6 as input, converts it into shaft torque, and outputs it.

The reducer 8 reduces the rotational speed of the electric motor 7 by combining gears with different numbers of teeth, and the resulting amplified torque drives the wheelset 9, accelerating and decelerating the vehicle. A tachograph (not shown) is also attached to the wheelset 9 to measure vehicle speed. The auxiliary inverter 10 receives DC power between the converter 5 and the electric motor inverter 6, converts it into three-phase AC power, and outputs it.

The auxiliary equipment 11 is service equipment such as vehicle lighting and air conditioning, and operates on power supplied by the auxiliary equipment inverter 10. The driver's cab 12 is equipped with a display that displays the time, vehicle speed, battery information, etc., and an input device that allows the driver to input driving commands, etc., into the control device 13. This battery system 100 is a device that stores energy to power the railway vehicle.

The cab 12 may also be equipped with a remote control unit capable of remotely operating contactors 112, 113 (Figure 4) and other switching devices. For example, if the vehicle detects a regenerative overvoltage, the switching device for the battery pack, which is a major component of the battery storage system 100, may be automatically shut off. This situation is displayed on the cab, and the driver can see it, consult a maintenance shop, and then remotely close the battery pack switching device from the cab 12 to restart the system. The remote control unit is primarily used for battery replacement, which is performed while the vehicle is parked for maintenance, and is operated remotely because an arc can fly when a worker inserts or removes the service connector 114, posing a risk.

This battery electric train drive system 1A is charged with DC charging power output from the converter 5 and discharged to the motor inverter 6 and the auxiliary inverter 10. When the vehicle is applying regenerative braking, it also charges with DC charging power output from the motor inverter 6. The vehicle control device 13 outputs control signals to the converter 5, motor inverter 6, and auxiliary inverter 10 based on driving commands, the state of this battery electric train system 100, the state of the pantograph 2, etc., and controls the entire battery electric train drive system 1A. While this battery electric train system 100 is suitable for battery electric trains, it is not limited to these applications and is also suitable for hybrid diesel railcars, for example.

Figure 3 shows the system configuration of the hybrid drive system 1B. A hybrid railcar equipped with the hybrid drive system 1B is a railway vehicle that is equipped with a storage battery system 100 on a conventional diesel railcar, charges with regenerative power during braking, and provides assistance from the storage battery and motor during power running. A hybrid railcar is a railway vehicle that does not use power from overhead lines, but runs on power generated by the engine and power from the storage battery. The engine does not operate constantly, but starts when continuous acceleration commands are input or when the storage battery's charge rate drops.

In this hybrid drive system 1B, instead of an overhead line 14 and pantograph 2, the engine 3 has an engine 3 and a generator 4. The engine 3 outputs shaft torque according to an engine speed command value from a vehicle control device 13. The generator 4 receives the shaft torque of the engine 3 as input, converts it into three-phase AC power, and outputs it.

Converter 5 receives the three-phase AC power output from generator 3, converts it into DC power corresponding to the commanded amount of power, and outputs it. The subsequent system configuration is the same as that of battery-powered electric railcar drive system 1A. The following explanation of Example 1 will be based on a battery-powered electric railcar, but the main parts of the invention also apply to hybrid diesel railcars.

Figure 4 shows the circuit configuration of the battery system 100. The battery system 100 has multiple battery boxes 101 connected in parallel and is connected to the battery train drive system 1A via the battery system P terminal 100P and the battery system N terminal 100N. The battery system 100 is often grounded to a ground point 15 on the P terminal 100P side, the N terminal 100N side, or an intermediate potential point of the battery system 100. While the battery system 100 is illustrated only in the case where the N terminal 100N side is grounded, this configuration is not limiting.

The battery box 101 has a housing indicated by the dashed line in Figure 4, and is attached to the railway vehicle as a unit of this housing. Multiple battery boxes 101 are connected in parallel via the battery box 101P terminal 101P and the battery box 101N terminal 101N, forming the battery system 100. Each battery box 101 contains multiple battery groups 111, group contactors 112, box contactors 113, and a service connector (also called a "service plug") 114.

The storage battery group 111 is a replacement unit in which multiple battery modules 201 (FIG. 5) are connected in series or parallel and separated by a service connector 114. This division is designed to be convenient for the mechanism and/or electrical control. The voltage and capacity of the storage battery group 111 increase in proportion to the number of battery modules 201 connected in series within the storage battery group 111, and the maximum current and capacity of the storage battery group 111 increase in proportion to the number of battery modules 201 connected in parallel.

The number of series connections in the storage battery group 111 is designed to set a voltage that allows the converter 5 and motor inverter 6 of this battery electric railcar traction system 1A to operate efficiently. The number of parallel connections in the storage battery group 111 is an integer of two or more (FIGS. 10 to 13) within one box. Here, the battery module 201 is a collection of multiple battery cells connected in series or parallel for easy handling. A battery cell is the smallest unit of a battery, individually packaging the chemical reaction system of the battery.

Each group contactor 112 is a contactor provided for one storage battery group 111, and corresponds to the "group switching device 112 for each group" as defined in the present invention. Each battery box contactor 113 is a contactor provided for one battery box 101, and corresponds to the "each box switching device 113 connected in series to a connection point 115N where multiple storage battery groups 111 are connected in parallel, with the polarity opposite to the polarity of the group switching devices 112 connected in series" as defined in the present invention. This battery box contactor 113 is a switching device whose circuit contacts are opened and closed by a remote control signal transmitted from the vehicle control device 13.

Switchgear can be a variety of devices, including contactors, relays, circuit breakers, and switches, depending on their switching mechanism, current interruption capacity, and response speed, but any switching device that opens and closes the circuit contacts using a remote control signal will suffice. Each group contactor 112 and each box contactor 113 each has one contact and switching mechanism, and all of these contactors can operate independently. The service connector 114 is a switch that opens and closes directly, manually, rather than remotely.

The service connector 114 is installed between the contactor and the storage battery, but is not limited to this configuration. Furthermore, the service connector 114 is always closed except during operations such as battery replacement. However, due to its nature of being opened and closed manually, it is unsafe to use it in situations where cross currents occur when the closing operation is performed.

In this battery system 100, each group contactor 112 is installed on the positive side of each battery group 111 and on the negative side of the battery group 111 P-side connection point 115P, and each box contactor 113 is installed on the negative side of the battery group 111 N-side connection point 115N and on the positive side of the battery box 101 N terminal 101N, one for each battery box 101. In this battery system 100, when the service connector 114 is closed, the negative side of each battery group 111 is already connected. Note that this configuration may be reversed.

The battery system 100 has roughly three advantages. First, each group contactor 112 can be remotely closed to connect the battery groups 111 in parallel and generate a cross current. Second, by closing each group contactor 112 and each box contactor 113, the battery boxes 101 can be connected in parallel on a box-by-box basis and connected to the battery system 100. Third, by closing each box contactor 113 and individually opening and closing each group contactor 112, any battery group 111 can be individually connected to the battery system 100.

Figure 5 is a block diagram showing the paralleling control system 200 in the battery electric train drive system 1A of Figure 2. The paralleling control system 200 is primarily composed of a vehicle control device 13, multiple battery boxes 101, a pantograph 2, a converter 5, an auxiliary inverter 10, and a driver's cab 12. The configuration and operation will be explained below.

The battery box 101 includes a plurality of storage battery groups 111, a battery box control board 205, a current sensor (CT: Current Transformer) 203 installed in each storage battery group 111 and converting the current value flowing through it into a voltage signal, a voltage sensor (PT: Potential Transformer) 204 installed in each storage battery group 111 and converting the voltage value into a voltage signal, each group contactor 112, and each box contactor 113.

The storage battery group 111 is composed of multiple battery modules 201. Each battery module 201 is provided with a cell control board 202 that monitors the status of the multiple battery cells contained therein. The cell control board is a board equipped with sensors and communication functions, and in this storage battery system 100, it measures the voltages of all cells in the battery module 201 and the temperature at a representative point, and transmits the results as signals to a battery control board 205.

The battery box control board 205 is a control board installed in each battery box 101 and includes a battery status analysis unit 206 and an in-box contactor control unit 207. The battery status analysis unit 206 is a calculation unit that analyzes the battery status inside the box and transmits information to the vehicle control device 13 and the in-box contactor control unit 207.

The battery state analysis unit 206 receives as input the cell voltages and temperatures transmitted from all cell control boards 202, the group currents transmitted from all current sensors 203, and the group voltages transmitted from all voltage sensors 204. The battery state analysis unit 206 outputs the group resistances, group voltages, cell resistances, and maximum cell voltages required for paralleling control to the vehicle control unit 13, and outputs a battery abnormality determination to the in-box contactor control unit 207 and the vehicle control unit 13.

Cell resistance is calculated, for example, by calculating the charge rate of each cell from battery information, and then calculating the resistance from the battery temperature and resistance degradation rate of each cell. Methods for calculating the charge rate and resistance degradation rate are generally known and will not be described in detail here, but group current is used in these calculations. Group resistance is calculated as the sum of component resistances that reflect the series-parallel connection of all cell resistances within the storage battery group 111. Each group voltage is the detected value of the voltage sensor 204. Cell voltage is the detected value of the cell controller 202.

It is most desirable to calculate the cell resistance and cell voltage individually for all cells, but this can be simplified. As an example of simplification, if there are performance limitations due to the battery box control board 205 or the number of voltage sensors and temperature sensors, the average cell resistance may be output, and the voltage of the highest cell may be output. Battery abnormality determination determines whether the battery's group voltage, group current, cell voltage, temperature, etc. have reached abnormal values.

The box-internal contactor control unit 207 is a control unit that operates the contactors in accordance with the contactor operation signal and opens the contactors in the event of an abnormality, protecting the battery. The box-internal contactor control unit 207 receives as input the contactor operation command output from the vehicle control device 13, the battery abnormality determination output by the battery state analysis unit 206, the group contactor status output by all group contactors 112, and the box contactor status output by all box contactors 113, and outputs group contactor operations to each group contactor 112 and box contactor operations to each box contactor 113.

The box contactor control unit 207 operates each group contactor 112 and each box contactor 113 in accordance with the contactor operation command output from the vehicle control device 13. If a battery abnormality determination is input from the battery state analysis unit 206, it opens each group contactor 112 and each box contactor 113 in response to the abnormality, regardless of the contactor operation command. In addition, if the state of each group contactor or each box contactor does not match the contactor operation command, it sends a contactor operation command again. If the state does not match the contactor operation command for a long period of time, it sends a contactor failure determination to the vehicle control device 13.

Generally, the electrical box control board 206 has various other functions, but these will not be described in detail here. The vehicle control device 13 is a device that controls the entire battery electric train drive system 1A. The paralleling control system 200 integrates information from the entire system and issues instructions for opening and closing contactors and charging and discharging batteries.

The vehicle control device 13 has a cross current calculation unit 208, a voltage adjustment target value calculation unit 209, and a parallelization control unit 210. Generally, the vehicle control device 13 has various other functions in addition to these, but these will not be described in detail here. The cross current calculation unit 208 inputs battery status information (each group resistance, each group voltage, cell resistance, cell voltage) for all battery boxes 101, determines whether each contactor can be closed, and outputs the result. Whether a contactor can be closed is determined, for example, based on whether a battery cell is predicted to be overvoltage.

In this case, the cross current calculation unit 208 first calculates the cross current using the above formula (1), and then calculates the closed circuit voltage CCVi of battery cell i when the cross current flows using the following formula (2): where OCVi is the open circuit voltage of the cell, Ri is the resistance value of battery cell i, and N is the number of parallel battery cells in the storage battery group 111.

When the closed circuit voltage CCVi at the time of cross current occurrence, as defined by the above formula (2), is less than the threshold for determining a high voltage abnormality for all battery cells i through which current flows when the contactor is operated, if the cross current is a charging current, or greater than the threshold for determining a low voltage abnormality for the cross current is a discharging current, the contactor can be closed; otherwise, it cannot be closed.

If it is not possible to perform calculations for all battery cells i, the possibility of contactor operation is determined based on, for example, whether a high voltage abnormality does not occur in the battery cell with the highest open-circuit voltage OCVi of the storage battery group 111 being charged, and whether a low voltage abnormality does not occur in the battery cell with the lowest open-circuit voltage OCVi of the storage battery group 111 being discharged.

Furthermore, the contactor closing operation is only possible if the overcurrent does not exceed the upper limit current of the battery cells, modules, contactors, cables, fuses (not shown), etc. If the cross current calculation unit 208 determines that the contactor closing operation is not possible due to the occurrence of a cross current, the voltage adjustment target value calculation unit 209 is a calculation unit that causes the parallelization control unit 210 to charge or discharge the storage battery groups 111 or battery boxes 101 to be paralleled, and calculates a voltage target value that makes the voltages of the storage battery groups 111 or battery boxes 101 to be paralleled equal.

The system outputs the voltage adjustment target values for each storage battery group 111 and each storage battery box 101 individually using battery status information (each group resistance, each group voltage, cell resistance, cell voltage) of all battery boxes 101 and the charging availability vehicle status output by the pantograph 2 as inputs. In a battery train, whether charging is possible or not depends on the vehicle's location on the line.

When overhead wires 14 are present on the vehicle and the pantograph 2 is in contact with the overhead wires 14, charging is possible, and the voltages are made uniform through the charging operation of the converter 5. Therefore, the voltage adjustment target value of each storage battery group 111 is the maximum storage battery group 111 voltage in the respective box 101, and the voltage adjustment target value of each storage battery box 101 is the maximum storage battery box 101 voltage in this storage battery system 100.

In contrast, when there are no overhead wires on the vehicle and the pantograph 2 is not in contact with the overhead wire 14, charging is not possible, so the voltage is made uniform by the discharge operation of the auxiliary inverter 10. Therefore, the voltage adjustment target value for each storage battery group 111 is the lowest storage battery group 111 voltage in the respective box 101, and the voltage adjustment target value for each storage battery box 101 is the lowest storage battery box 101 voltage in the storage battery system 100. The safest voltage adjustment target value is the minimum or maximum voltage described above, but in order to shorten the voltage adjustment time, there is no problem even if the voltage is within a range in which cross currents are generated, as long as the cross currents are within a safe range.

The paralleling control unit 210 is a control unit that performs contactor opening and closing operations and battery charging/discharging instructions. It receives inputs such as the vehicle charging status output from the pantograph 2, battery abnormality determination and contactor abnormality determination output from all battery boxes 101, contactor closing operation determination output from the cross current calculation unit 208, the voltage adjustment target value output from the voltage adjustment target value calculation unit 209, and the system startup command and running interrupt command output from the cab 12, and outputs contactor operation commands for all battery boxes 101, pantograph 2 operation commands, converter 5 output commands, auxiliary inverter 10 output commands, and display information for the cab 12.

The driver evaluates the cab 12 display information displayed on the monitor in the cab 12 and issues a command from the cab 12. The main operations of the paralleling control unit 210 are contactor opening/closing commands and voltage adjustment when cross current is predicted to occur. After receiving a system start command from the cab 12, the contactor opening/closing command is issued when the cross current calculation unit 208 determines that the contactor closing operation is possible for the contactor to be closed, and if there are no problems in the battery abnormality determination or contactor abnormality determination, the contactor is closed.

If the cross current calculation unit 208 determines that the contactor closing operation is not possible due to the occurrence of a cross current, the parallelization control unit 210 charges or discharges the storage battery groups 111 or battery boxes 101 to be paralleled, and equalizes the voltages of the storage battery groups 111 or battery boxes 101 to be paralleled. Here, the order of parallelization is such that the storage battery groups 111 in each box are paralleled, and then the storage battery boxes 101 are paralleled.

Since charging is possible in sections where overhead wires are present on the vehicle, the paralleling control unit raises the pantograph 2 to make contact, operates the converter 5, and then operates the contactors of the low-voltage storage battery group 111 or battery boxes individually to connect them and charge them up to the target value of the voltage adjustment target value calculation unit 209. After charging, the cross current calculation unit 208 determines whether the contactors can be closed, so parallel connection is performed.

On the other hand, since charging is not possible in sections where there are no overhead lines on the vehicle, the paralleling control unit operates the auxiliary inverter 10, and then operates the contactors of the high-voltage storage battery group 111 or battery boxes individually to connect them and discharge them to the target value of the voltage adjustment target value calculation unit 209. After charging, the cross current calculation unit 208 determines whether the contactors can be closed, so parallel connection is performed.

When there are three or more storage battery groups 111 or storage battery boxes 101 in a box, and the cross current calculation unit 208 determines that parallelization is possible but the voltages do not match and a certain cross current value occurs, it is generally desirable to connect the batteries in parallel starting from the lower voltage side, as shown in Patent Document 2. This is because, due to the electrochemical characteristics inside lithium-ion batteries, the problem caused by actual cross current is more serious when the battery exceeds the upper closed circuit voltage limit as shown in Equation (2) above than when the battery exceeds the lower closed circuit voltage limit, so it is safer to gradually align the voltages starting from the low voltage side where the cross current becomes a charging current.

Figure 6 is a flowchart 300 showing the processing steps of the paralleling control unit 210 in Figure 5. That is, the paralleling control of Example 1 shown in Figure 6 is the overall paralleling control by the paralleling control unit 210 from the start of the vehicle system (S2) to the completion of paralleling processing of the battery system (S30) and entering a battery-powered running state. The running interrupt command (S8) is a command that causes the paralleling control unit 210 to interrupt voltage adjustment and transition to a running state midway through the paralleling control flowchart 300 shown in Figure 6. In start step S1, the paralleling control flowchart 300 by the paralleling control unit 210 begins. At this time, the battery electric train drive system 1A is in the off state, and all group contactors 112 and all box contactors 113 are in the open state. Note that the order of priority for aligning the contacts within each box and then by box is more convenient for emergency running; for example, a battery electric train can be powered with just one box.

In vehicle system on determination step S2, the paralleling control unit 210 determines whether the vehicle system key is on. If the key is on, the paralleling control unit 210 proceeds to the next step, and if the key is off, it returns to S2. In battery status analysis step S3, the battery box control boards 205 in all boxes analyze the battery status (each group resistance, each group voltage, cell resistance, cell voltage) and battery abnormality determination for each battery box 101, and transmit the results to the vehicle control device 13.

In the target box selection step S4, the parallelization control unit 210 selects a target box i for parallelizing the battery groups 111 in the battery boxes 101. The order of the i may be arbitrary, but in order to maximize the number of battery boxes 101 that can be used when switching to a driving cut-in, it is desirable to perform the parallelization control in order of the least amount of charge/discharge required for voltage adjustment of the battery groups 111 in the box. Furthermore, it is desirable to postpone parallelization control for boxes that have been determined to have a battery abnormality or contactor abnormality, as this is disadvantageous for emergency driving.

In the inter-group cross current calculation step S5, the parallelization control unit 210 calculates the cross current value when the cross current calculation unit 208 closes each group contactor 112 in the battery box 101, and determines whether the inter-group cross current value is small and whether safe parallelization is possible. When there are three or more battery groups 111, the parallelization control unit 210 calculates the cross current value when paralleling is performed from the low-voltage side.

In inter-group cross current safety determination step S6, if it is determined in inter-group cross current calculation step S5 that the inter-group cross current value is small and safe parallel connection is possible, proceed to each group contactor closing step S7. In inter-group cross current safety determination step S6, if it is determined that the inter-group cross current value is large and safe parallel connection is not possible, proceed to inter-group voltage adjustment from running interrupt determination step S8 to each box contactor opening step S16.

In each group contactor closing step S7, the paralleling control unit 210 closes each group contactor 112 in each battery box i to connect the storage battery groups 111 in parallel within a range where the inter-group cross current value is small and safe parallel connection is possible, based on the contactor closure determination calculated by the cross current calculation unit 208. If the paralleling control unit 210 receives a traveling cut-in command from the cab 12 as the first stage of inter-group voltage adjustment in traveling cut-in determination step S8, it interrupts inter-group voltage adjustment and proceeds to each group contactor closing step S7.

In the traveling interrupt determination step S8, the parallelization control unit 210 does not necessarily operate at a single point between steps S6 and S8, but always operates during the voltage adjustment operations S8 to S16, and once a traveling interrupt command is issued, it simply proceeds to step S7 for closing the contactors of each group. In the target group selection step S9, the parallelization control unit 210 selects a target group k for paralleling the storage battery groups 111 in the box. The order of k may be arbitrary, but it is desirable to postpone the group k for which a battery abnormality or contactor abnormality has been determined.

In chargeability status determination step S10, the parallelization control unit 210 determines whether the vehicle is chargeable or not, corresponding to the contact status of the pantograph 2 with the overhead wire, and determines whether voltage adjustment should be performed by charging or discharging, and the voltage adjustment target value calculation unit 209 calculates the voltage adjustment target value. If the pantograph 2 is in contact with the overhead wire 14 and charging is possible, the parallelization control unit 210 sets the voltage adjustment target value to the highest battery group 111 voltage and proceeds to charging group connection step S11. Conversely, if the pantograph 2 is not in contact with the overhead wire 14 and charging is not possible, the voltage adjustment target value is set to the lowest battery group 111 voltage and proceeds to discharging group connection step S13.

In the charging group connection step S11, if the target storage battery group 111k has a voltage lower than the voltage adjustment target value and needs to be charged, the parallelization control unit 210 connects the group contactors 112 and box contactors 113 corresponding to the target storage battery group 111k, connects it to the battery electric train traction system 1A, and makes it ready for charging. If the target storage battery group 111k has a voltage higher than the voltage adjustment target value and does not need to be charged, the parallelization control unit 210 proceeds to the next step.

In the storage battery group 111 charging step S12, if the target storage battery group 111k has a voltage lower than the voltage adjustment target value and needs to be charged, the parallelization control unit 210 starts the converter 5 to charge the target storage battery group 111k up to the voltage adjustment target value. Conversely, if the target storage battery group 111k has a voltage higher than the voltage adjustment target value and does not need to be charged, the process proceeds to the next step.

In the discharge group connection step S13, if the target storage battery group 111k has a voltage higher than the voltage adjustment target value and therefore needs to be discharged, the parallelization control unit 210 connects the group contactors 112 and box contactors 113 corresponding to the target storage battery group 111k, connects them to the battery electric train traction system 1A, and sets them in a state where they can be discharged. Conversely, if the target storage battery group 111k has a voltage lower than the voltage adjustment target value and therefore does not need to be discharged, the parallelization control unit 210 proceeds to the next step.

In the storage battery group 111 discharging step S14, if the target storage battery group 111k has a voltage higher than the voltage adjustment target value and therefore needs to be discharged, the parallelization control unit 210 starts the auxiliary inverter 10 to discharge the target storage battery group 111k to the voltage adjustment target value. Conversely, if the target storage battery group 111k has a voltage lower than the voltage adjustment target value and therefore does not need to be discharged, the process proceeds to the next step.

In the paralleling control unit 210, the cross current calculation unit 208 again determines whether or not the contactors can be closed in inter-group voltage adjustment completion determination step S15. If the determination result indicates that voltage adjustment of each storage battery group 111 in the box is not complete and all group contactors 112 cannot be closed, the process returns to before the travel interrupt determination step S8 and proceeds to voltage adjustment of the next storage battery group 111. Conversely, if voltage adjustment of all storage battery groups 111 is complete and it is determined that each group contactor 112 can be closed, the process proceeds to each box contactor opening step S16.

In the individual box contactor opening step S16, the paralleling control unit 210 opens each box contactor 113. This is to isolate battery box 101i from the battery electric train traction system 1A and prevent cross currents from flowing between battery box 101i and battery box 101i+1 when the voltage of battery box 101i+1 is next adjusted. At this time, each group contactor 112 can be in the closed state.

After each box contactor opening step S16, the paralleling control unit 210 merges into each group contactor closing step S7. In all box-group voltage adjustment completion determination step S17, the paralleling control unit 210 determines whether voltage adjustment between the storage battery groups 111 in all battery boxes 101 has been completed. If not completed, the paralleling control unit 210 returns to target box selection step S4, changes the target battery box for voltage adjustment to the next battery box (i+1), and repeats the in-box voltage adjustment process. Conversely, if voltage adjustment of each storage battery group 111 in all battery boxes 101 has been completed, the process proceeds to the next step.

In inter-box cross current calculation step S18, the parallelization control unit 210 calculates the cross current value when the cross current calculation unit 208 closes each box contactor 113 in the battery system 100 while each group contactor 112 is in the closed state at the end of step S17, and determines whether the inter-box cross current value is small and safe parallelization is possible. If the result of this determination is that there are three or more battery boxes 101, the parallelization control unit 210 calculates the cross current value when parallelization is performed from the low-voltage side.

If the paralleling control unit 210 determines in step S19 that the inter-box cross current value is small and safe parallel connection is possible in step S18 of determining whether the inter-box cross current is safe, the process proceeds to step S20 of closing each box contactor. Conversely, if the paralleling control unit 210 determines that the inter-box cross current value is large and safe parallel connection is not possible, the process proceeds to step S21 of determining whether the traveling interruption has occurred and step S29 of determining whether the inter-box voltage adjustment is complete to adjust the inter-box voltage.

In the each box contactor closing step S20, the parallelization control unit 210 closes each box contactor 113 in the battery system 100 to connect the battery boxes 101 in parallel, based on the contactor closure determination calculated by the cross current calculation unit 208, within the range where the inter-box cross current value is small and safe parallel connection is possible.

Figure 7 is a flowchart 400 showing the control procedure for running cut-in in the battery electric train drive system 1A of Figure 2. In the running cut-in determination step S21 in Figure 6, as in the running cut-in determination step S8, if the paralleling control unit 210 receives a running cut-in command from the driver's cab 12 as the first stage of inter-box voltage adjustment, it interrupts inter-box voltage adjustment and proceeds to running cut-in start step T1 in the running cut-in control flowchart 400 of Figure 7. The paralleling control unit 210 uses the power of the box with the higher voltage to power the boxes, and when that voltage drops and becomes equal, it combines them.

The parallelization control unit 210 does not necessarily operate the running interrupt determination step S21 at a single point between steps S19 and S22, but rather operates it constantly during the voltage adjustment operations from S22 to S29. When a running interrupt command is issued, the parallelization control unit 210 simply proceeds to start step T1 of the running interrupt control flowchart 400.

In the target box selection step S22, the parallelization control unit 210 selects a target box i for paralleling the battery boxes 101 in the battery system. The order of i may be arbitrary, but it is desirable to select boxes for which a battery abnormality or contactor abnormality has been determined last. In the chargeability status determination step S23, the parallelization control unit 210 determines the chargeability vehicle status corresponding to the contact status of the pantograph 2 with the overhead wire, as in the chargeability status determination step S10. Based on the determination result, the parallelization control unit 210 determines whether voltage adjustment should be performed by charging or discharging. At that time, the voltage adjustment target value calculation unit 209 calculates the voltage adjustment target value.

If the pantograph 2 is in contact with the overhead line 14 and charging is possible, the parallelization control unit 210 sets the voltage adjustment target value to the maximum battery box voltage and proceeds to charging box connection step S24. Conversely, if the pantograph 2 is not in contact with the overhead line 14 and charging is not possible, the voltage adjustment target value is set to the minimum battery box voltage and proceeds to discharge box connection step S26.

In charging box connection step S24, similar to charging group connection step S11, if the target battery box i has a lower voltage than the voltage adjustment target value and requires charging, the parallelization control unit 210 connects each box contactor 113 corresponding to the target battery box i (at this time, each group contactor 112 is already closed). Then, the parallelization control unit 210 connects each box contactor 113 corresponding to the target battery box i to the battery electric train traction system 1A, making it ready for charging. Conversely, if the target battery box i has a higher voltage than the voltage adjustment target value and does not require charging, the process proceeds to the next step.

In the battery box charging step S25, similar to the storage battery group 111 charging step S12, if the target battery box i has a voltage lower than the voltage adjustment target value and needs to be charged, the parallelization control unit 210 activates the converter 5 to charge the target battery box i up to the voltage adjustment target value. Conversely, if the target battery box i has a voltage higher than the voltage adjustment target value and does not need to be charged, the process proceeds to the next step.

In the discharge box connection step S26, similar to the discharge group connection step S13, if the target battery box i has a higher voltage than the voltage adjustment target value and discharge is required, the parallelization control unit 210 connects each box contactor 113 corresponding to the target battery box i (at this time, each group contactor 112 is already closed). Then, the parallelization control unit 210 connects each corresponding box contactor 113 to the battery electric train traction system 1A, making it ready for discharge. Conversely, if the target battery box i has a lower voltage than the voltage adjustment target value and discharge is not required, the process proceeds to the next step.

In battery box discharging step S27, similar to battery box discharging step S14, if the target battery box i has a higher voltage than the voltage adjustment target value and discharging is required, the parallelization control unit 210 starts the auxiliary inverter 10 and discharges the target battery box i to the voltage adjustment target value. Conversely, if the target battery box i has a lower voltage than the voltage adjustment target value and discharging is not required, the parallelization control unit 210 proceeds to the next step.

In each box contactor opening step S28, the parallelization control unit 210 opens each box contactor 113 of battery box 101i. This is to isolate battery box 101i from the battery electric train traction system 1A and prevent cross current from flowing between battery box 101i and battery box 101i+1 when adjusting the voltage of battery box 101i+1 next. At this time, each group contactor 112 can be in the closed state.

In box-to-box voltage adjustment completion determination step S29, the parallelization control unit 210 determines whether voltage adjustment has been completed for all battery boxes 101, similar to step S17 for determining completion of voltage adjustment between all box groups. If not completed, the process returns to target box selection step S22, the next battery box i+1 is selected for voltage adjustment, and the voltage adjustment process within the box is repeated. If voltage adjustment has been completed for all battery boxes 101, the parallelization control unit 210 proceeds to step S20 for closing the contactors of each box.

In end step S30, the parallelization control unit 210 completes the parallelization process, and the battery system 100 is connected to the battery train traction system 1A and is in a battery-powered running state. In this way, the battery system 100 can adjust the voltages of all the battery groups 111 and all the battery boxes individually, allowing any combination of voltages for the battery groups 111 and battery boxes 101. Furthermore, regardless of whether the railcar is in a chargeable state or not, the battery system 100 can automatically adjust the voltages of all the battery groups 111 and battery boxes 101 individually and connect them in parallel within a safe cross current range.

These charging and discharging operations for voltage adjustment require a certain amount of time. The battery-powered electric train traction system 1A desirably starts running after all of the battery boxes 101 and the battery groups 111 therein in the battery system 100 are connected in parallel, but in an emergency, it is necessary to be able to start running even if maximum output is not available.

Therefore, when a running interrupt command is output from the cab 12, it is necessary to interrupt the voltage adjustment process shown in the flowchart 300 and immediately set the battery system 100 to a state where it can be charged and discharged. In this case, even if not all the batteries are connected in parallel, each battery group 111 has a voltage that can operate the motor inverter 6, so that low-power running is possible.

Furthermore, in an actual battery system 100, due to issues such as control division, if the battery groups 111 in the battery box 101 are not all connected in parallel, the battery box 101 may not be able to connect to the battery system 100. In such cases, it is important to first adjust the voltage between the battery groups 111 in the battery box 101 so that each battery box 101 can be connected to the battery system 100 in an emergency.

Therefore, the parallelization control flowchart 300 shown in Figure 6 is characterized in that voltage adjustment between battery boxes 101 is performed after all voltage adjustments of the battery groups 111 in each battery box 101 have been completed. This allows the voltages in each battery box to be equalized as quickly as possible, and even if a traveling interrupt command is issued during voltage adjustment, the battery boxes 101 are used one by one starting with the highest voltage, and the voltage of the battery box 101 in use drops as it is used. Each time the voltage of the battery box 101 in use becomes equal to that of the unused battery box 101, the battery box 101 is connected in parallel again, thereby maximizing the travel distance.

This will be explained using a control flowchart 400 for a driving cut-in. Figure 7 shows the control flowchart 400 for a driving cut-in according to Example 1 of the present invention. At any point in the parallel control flowchart 300 of Figure 6, a driving cut-in is issued by the vehicle system, and the method of using the storage battery when a driving cut-in is performed is shown from the driving cut-in start step T1.

The vehicle system starts the control procedure of the travel interruption control flowchart 400 at travel interruption start step T1 in Figure 7. Travel interruption start step T1 in Figure 7 is the same as that in Figure 6. At this time, in accordance with the parallelization control flowchart 300, in this battery system 100, each group contactor 112 is in the closed state and all individual box contactors 113 are in the open state within the range where there are no cross current value problems in all battery boxes 101.

In the usable battery box determination step T2, the parallelization control unit 210 determines whether each battery box 101 can be used individually. "Individually usable" means that the battery boxes 101 can be connected individually to the battery electric train drive system 1A and can run, regardless of the cross current value when the boxes are connected in parallel.

The criteria for judgment are the battery abnormality judgment and contactor abnormality judgment output by the battery box control board 205 (FIG. 5), and the closed state of each group contactor. The closed state of each group contactor assumes the case where the battery box 101 cannot be connected to the battery system 100 unless all of the battery groups 111 in the battery box are connected in parallel due to issues such as the division of control of the actual battery system.

In the highest voltage box connection step T3, the battery box control board 205 closes the box contactors 113 of each battery box 101 that the cross current calculation unit 208 has determined can be connected in parallel, starting with the battery box 101 with the highest voltage among the usable battery boxes 101 determined in step T3, thereby connecting the battery train traction system 1A and enabling it to run.

In running step T4, the battery electric train drive system 1A runs using the power of the battery system 100. During this time, the voltage of the battery 101 in use drops as the charge rate decreases. In box voltage matching step T5, it is determined that the voltage of the battery box 101 whose voltage has dropped due to running and the voltage of the usable battery box 101 that is not yet in use and whose box-to-box contactor 113 is open are now the same.

This determination depends on the accuracy of the battery's open-circuit voltage, but because this accuracy decreases as the current value increases, it is desirable to make the determination at a current value below a certain level. In each box contactor closing step T6, the parallelization control unit 210 closes the inter-box contactor 113 of an unused battery box 101 that has the same voltage as determined in box voltage matching step T5, thereby connecting that battery box 101 in parallel to the storage battery system 100. At this time, the voltage of the battery box in use and the newly connected battery box are nearly identical, so the cross current is small.

In the all-box parallelization determination step T7, the parallelization control unit 210 determines whether all usable battery boxes 101 are connected in parallel. If not all are connected in parallel, the parallelization control unit 210 returns to the step before the traveling step T4; if all are connected in parallel, it proceeds to the next step.

The parallelization control unit 210 ends the running interrupt control flowchart in end step T8. At this time, all available battery boxes 101 are parallelized. From here, the parallelization control system 200 in Figure 5 will be shown. The cab transmission information issued from the parallelization control unit 210 to the cab 12 will be explained.

The information transmitted from the cab allows the driver to check the progress of the paralleling control and provides information on whether or not to issue a running interrupt command during the paralleling control flowchart 300. Typical information transmitted from the cab includes the contactor open/close status, the voltage of each storage battery group 111, the voltage of each storage battery box 101, the remaining time for voltage adjustment, the possible driving range, and the maximum acceleration force.

The contactor opening/closing information, the voltage of each storage battery group 111, and the voltage of each storage battery box 101 are all the contactor opening/closing information, the voltage of each storage battery group 111, and the voltage of each storage battery box 101 in the storage battery system 100. The remaining voltage adjustment time is the remaining time until the parallelization control flowchart 300 is completed, and is a value calculated based on the voltages of each storage battery group 111 and each storage battery box 101, their battery capacities, the possible charge rate of the converter 5, and the possible discharge rate of the auxiliary inverter 10.

Because the speed of voltage adjustment is predictable, the number of storage battery groups 111 and battery boxes that can be connected in parallel and the voltage at that time can be predicted if voltage adjustment continues at each future point in time. The possible cruising distance indicates the possible cruising distance at each future point in time from the present when traveling according to the control procedure of the traveling interrupt control flowchart 400 using the storage battery groups 111 and battery boxes that can be used in the state of the battery system 100 at the time the traveling interrupt command is issued.

The maximum acceleration force indicates the maximum acceleration force using the storage battery group 111 and battery boxes that can be used at each point in time from the present to the future in the state of the battery system 100 at the time the travel interrupt command is issued. This maximum acceleration force is a value that increases each time the number of boxes connected in parallel increases according to the control procedure of the travel interrupt control flowchart 400, but in many cases, the maximum acceleration force at the stage with the fewest number of parallel connections is of concern, so it is sufficient to display the initial value.

Because the cruising range and maximum acceleration force are values that change as the voltage regulation progresses, the cab 12 must display how they change over the duration of the voltage regulation. Furthermore, the behavior differs depending on whether the voltage regulation corresponds to charging or discharging. The voltage regulation for charging and discharging will be described later using Figures 8 and 9. Here, although different from the example shown in Figure 4, an example of the battery storage system 100 will be described, which has two battery boxes 101, each containing two battery groups 111.

Although not shown, the voltage of the storage battery groups 111 within the boxes is Group 1 > Group 2, and the voltage of each box after adjusting the voltage of each group is also Box 1 > Box 2. The time required to adjust the voltage of each group is shorter for Box 1 than for Box 2, and voltage adjustment of each group within Box 1 begins. The voltage difference between each group and box is large, and parallel connection is not possible without voltage adjustment. To operate this battery electric train traction system 1A, at least one battery box is required in which all storage battery groups 111 within the box are connected in parallel. Therefore, without voltage adjustment, there is no battery box 101 that can operate this battery electric train traction system 1A, and the maximum acceleration force P and cruising range L will be zero.

Figure 8 shows a time-series switch opening/closing table and graph of the cruising range and acceleration force during charging using the parallel control of Figures 5 and 6. Figure 8 illustrates driving while charging, with the control procedure of the parallel control flowchart 300 of Figure 6 being executed by charging. The table in Figure 8 shows the operation of each group contactor 112, each box contactor 113, and converter 5 of the two battery boxes 101, and the graph in Figure 8 shows the dependence of maximum acceleration force P and cruising range L on voltage adjustment time.

The maximum acceleration force P and cruising range L correspond to the values when a driving interrupt command is received at that time. The horizontal position of the table and the voltage adjustment time axis of the graph are assumed to coincide. The operation of this diagram will be explained according to the voltage adjustment time axis. Note that maximum acceleration force P and cruising range L will be abbreviated as P and L hereafter.

Start step V1 is a step that indicates the start state of the parallelization control flowchart 300. All group contactors 112 and box contactors 113 in the battery system 100 are in the open state, and the converter 5 is in the stopped state. At this time, based on the prerequisites at the start, there are no battery boxes 101 that can operate the battery electric train traction system 1A, and P and L are 0.

In step V2 of adjusting the inter-group voltage within the first box, the voltages of each group within the first box are adjusted, and after this adjustment, the first box is connected in parallel. At this time, to charge group 2 in box 1, each group contactor 112 in group 1 of box 1 is open, each group contactor 112 and each box contactor 113 in group 2 in box 1 are closed, and all contactors in box 2 are open, and converter 5 is in charging operation.

At this time, group 2 in box 1 is charging, but for a while it is not possible to connect the groups in parallel, so P and L are 0. If we take t1 as the time when the voltages become close enough to allow parallel connection, then P and L are 0 up until time t1. After time t1, a certain amount of cross current occurs, but the group becomes connectable, and P and L increase discontinuously.

After this, P and L continuously increase as group 2 of 1 is charged. When inter-group voltage adjustment of box 1 is complete, P is set to P1 and L is set to L1. At the end of step V2, each box contactor 113 of box 1 is opened and all group contactors 112 are closed, connecting box 1 in parallel. The second intra-box inter-group voltage adjustment step V3 adjusts each group voltage in the second box, and after this adjustment, connects the second box in parallel.

At this time, to charge Group 2 in Box 2, each group contactor 112 in Group 1 in Box 2 is open, each group contactor 112 and each box contactor 113 in Group 2 in Box 2 are closed, and all group contactors 112 in Box 1 are closed and each box contactor 113 is open, and the converter 5 is in charging operation. At this time, Group 2 in Box 2 is charging. As with Box 1, if the voltages between the groups become close enough at time t2 to enable parallel connection, P and L are P1 and L1 until time t2. After time t2, a certain amount of cross current occurs, but parallel connection is possible, and L increases discontinuously as two battery boxes 101 become available according to the travel interrupt control 400. From then on, L increases continuously as Group 2 in Box 2 is charged.

On the other hand, P is a value that can be used immediately after a driving cut-in, so it does not change from P1. If P is P2 and L is L2 when inter-group voltage adjustment in Box 2 is complete, then P becomes P1 and L becomes L1 + L2 for the entire battery system 100. At the end of step V3, each box contactor 113 in Box 2 is opened, and all group contactors 112 are closed, connecting Box 2 in parallel.

Inter-box voltage adjustment step V4 adjusts the voltage of each box in the system, and after this adjustment, connects the boxes in parallel. At this time, to charge all groups in box 2, all contactors in box 2 are closed, all group contactors 112 in box 1 are closed, and each box contactor 113 is open, and converter 5 is in charging operation. At this time, box 2 is charged, and if the time when the voltage becomes close enough to that of box 1 to enable parallel connection is t3, P and L are P1 and L1 + L2 until time t3, and after time t3, a certain cross current occurs, but parallel connection is possible.

Since two battery boxes 101 are available for use, L continues to increase even though it is time t3. On the other hand, since P is a value that can be used in the situation immediately after a running interruption, it does not change from P1 until time t3 when the two boxes can be connected in parallel, increases discontinuously at t3, and then increases continuously thereafter.

At the end of step V4, the voltage state of box 2 becomes the same as that of high-voltage box 1, so P becomes 2P1 and L becomes 2L1 throughout the entire battery system 100. Step V5 is the state in which voltage adjustment is complete and the vehicle is in standby mode. At this time, all contactors 112, 113 within the battery system 100 are closed, and the converter 5 is stopped.

Figure 9 is a time series graph of the cruising range and acceleration force during discharging in the paralleling control of Figures 5 and 6. In other words, the control procedure of the paralleling control flowchart 300 of Figure 6 is executed by discharging. Here, instead of charging the converter 5, discharging is performed by operating the auxiliary inverter 10. Start step W1 is a step that indicates the start state of the paralleling control flowchart 300. All group contactors 112 and box contactors 113 in the battery system 100 are in the open state, and the auxiliary inverter 10 is in the stopped state. At this time, based on the prerequisites at the start, there are no battery boxes 101 that can operate the battery electric train drive system 1A, and P and L are 0.

In step W2 of adjusting the inter-group voltage within the first box, the group voltages within the first box are adjusted, and after this adjustment, the first box is connected in parallel. At this time, to discharge group 1 in box 1, each group contactor 112 in group 2 in box 1 is open, each group contactor 112 and each box contactor 113 in group 1 in box 1 are closed, all contactors in box 2 are open, and the auxiliary inverter 10 is in discharging operation.

At this time, group 1 in box 1 is discharging, but since it is not possible to connect the groups in parallel for a while, P and L are 0. If we assume that the time when the voltages become close enough to allow parallel connection is t1, then P and L are 0 up until time t1. After time t1, a certain amount of cross current occurs, but the group becomes capable of parallel connection, and P and L increase discontinuously.

After that, P and L continuously decrease as group 1 in box 1 is discharged. When the inter-group voltage adjustment in box 1 is complete, P is set to P1 and L is set to L1. At the end of step W2, each box contactor 113 in box 1 is opened and all group contactors 112 are closed, connecting box 1 in parallel. The second intra-box inter-group voltage adjustment step W3 adjusts each group voltage in the second box, and after the adjustment, connects the second box in parallel.

At this time, to discharge Group 1 in Box 2, each group contactor 112 in Group 2 in Box 2 is open, each group contactor 112 and each box contactor 113 in Group 1 in Box 2 is closed, all group contactors 112 in Box 1 are closed, and each box contactor 113 is open, causing the auxiliary inverter 10 to perform discharging. At this time, Group 1 in Box 2 is discharging. As with Box 1, if the voltages between the groups become sufficiently close at time t2 to enable parallel connection, P and L are P1 and L1 until time t2. After time t2, a certain amount of cross current occurs, but parallel connection is possible, and L increases discontinuously as the two battery boxes 101 become available for use according to the traveling interrupt control 400.

After this, L decreases continuously as Group 2 in Box 2 is discharged. Meanwhile, P remains unchanged from P1, as it is a value that can be used in the situation immediately after a driving cut-in. If P is P2 and L is L2 when inter-group voltage adjustment in Box 2 is complete, then P for the entire battery system 100 becomes P1 and L is L1 + L2. At the end of step W3, each box contactor 113 in Box 2 is opened, and all group contactors 112 are closed, connecting Box 2 in parallel.

In the inter-box voltage adjustment step W4, the voltage of each box in the system is adjusted, and after this adjustment, the boxes are connected in parallel. At this time, to discharge all groups in box 1, all contactors in box 1 are closed, all group contactors 112 in box 2 are closed, and each box contactor 113 is open, and the auxiliary inverter 10 is in discharging operation. At this time, box 1 is discharged, and if the time when the voltage is close enough to box 2 to enable parallel connection is t3, then P and L are P1, L1 + L2 until time t3, and after time t3, a certain cross current occurs, but parallel connection is possible.

Since two battery boxes 101 are available for use, L decreases continuously regardless of time t3. On the other hand, P is a value that can be used in the situation immediately after a driving interruption, so it does not change from P1 until time t3 when the two boxes can be connected in parallel, at which point it increases discontinuously and then decreases continuously. At the end of step W4, the voltage state of box 1 becomes the same as that of box 2, which has a low voltage, so for the entire battery system 100, P becomes 2P2 and L becomes 2L2.

Step W5 is the state where voltage adjustment is complete and the vehicle is in standby mode. At this time, all contactors in the system are closed and the auxiliary inverter 10 is stopped. As shown here, when adjusting voltage by discharging, the longer the discharge time is from the point at which paralleling becomes possible, the smaller P and L become. Therefore, when adjusting voltage by discharging, the range in which parallel connection is allowed even if some cross current occurs can be relaxed compared to when adjusting voltage by charging, as long as the components that make up the battery system are not damaged.

Here, the vehicle control device 13 determines whether the remaining driving distance L is equal to or greater than the remaining distance to important locations such as the next station where charging is possible or a location where passengers can disembark in a tunnel or bridge, and displays this information on the driver's cab 12 to assist the driver in deciding whether to cut in. From here, we will explain the features and advantages of the circuit configuration of the battery box 101 in Figure 4 shown in Example 1.

Figures 10 to 13 are circuit diagrams showing battery boxes 101a, 101b, 101c, and 101d with circuit configurations according to modified examples a to d. Figure 14 is a table comparing the effects of battery boxes 101a, 101b, 101c, and 101d according to modified examples a to d with the battery box 101 in Figure 4. Below, the circuit configuration and effects of each feature will be explained one by one.

4, each group contactor 112 is installed for each of the plurality of battery groups 111 on the positive side of the battery group 111 and closer to the north side than the connection point 115P on the battery group 111P side. Also, in the battery box 101, each box contactor 113 is installed on the north side of the connection point 115N on the battery group 111N side and closer to the north side than the battery box 101N terminal 101N, one for each battery box 101.

The features of this circuit configuration will be explained one by one for rows No. 1 to No. 7 in Figure 14. First, regarding whether or not parallel connection between storage battery groups 111 within a box can be achieved using contactors, this can be achieved by closing each group contactor 112. Second, regarding whether or not parallel connection between boxes can be achieved using contactors, this can be achieved by closing all group contactors 112 and box contactors 113 within the box.

Third, whether or not the voltage of each in-box battery group 111 can be adjusted individually can be achieved by closing each group contactor 112 and each box contactor 113 connected in series to the target battery group 111, and opening each group contactor 112 connected in series to the non-target battery group 111. Fourth, whether or not the parallel connection of the in-box battery groups 111 and the inter-box parallel connection can be achieved separately can be achieved by closing each group contactor 112 for the battery group 111, and by closing each box contactor 113 for the inter-box connection.

Fifth, the external connection terminals 101P and 101N of the battery box can be put into a power outage state by opening the group contactor 112 for 101P and by opening the box contactor 113 for 101N. Sixth, the earth fault current can be interrupted by opening the box contactor 113. Seventh, the number of contactors in a box [pieces/box] is N+1 [pieces/box], where N is the number of storage battery groups 111.

10 is a circuit diagram showing a battery box 101a according to a modified example. In this battery box 101a, the group contactors 112 are not present, and two box contactors 113 are installed per battery box 101, one on the positive side of each battery group 111 and the negative side of the battery group 111 P-side connection point 115P, and the other on the negative side of each battery group 111 and the positive side of the battery group 111 N-side connection point 115N.

The characteristics of this circuit configuration will be explained one by one for rows No. (1)1 to No. (7) in Figure 14. First, regarding whether or not parallel connection between storage battery groups 111 within a box can be achieved using contactors, this is not possible. Second, regarding whether or not parallel connection between boxes can be achieved using contactors, this can be achieved by closing both the P side and N side of each box contactor 113.

Third, it is not possible to individually adjust the voltage of each in-box battery group 111. Fourth, it is not possible to separately connect the in-box battery groups 111 in parallel and between boxes, because parallel connections between in-box battery groups 111 cannot be made using contactors. Fifth, it is possible to put the external connection terminals 101P, 101N of the battery box into a power outage state by opening both the P side and the N side of each box contactor 113.

Sixth, whether or not a ground fault current can be interrupted can be determined by opening each box contactor 113 on the N side. Seventh, the number of contactors in a box (units/box) is the minimum of 2 (units/box), where N is the number of storage battery groups 111. Figure 11 is a circuit diagram showing a storage battery box 101b with a circuit configuration according to a modification of the first embodiment. In the battery box 101b, one group contactor 113 is installed on each of the P side and N side of each storage battery group 111.

The features of this circuit configuration will be explained one by one for rows No. 1 to No. 7 in Figure 14. First, regarding whether or not parallel connection between storage battery groups 111 within a box can be achieved using contactors, this can be achieved by closing both the positive and negative sides of each group contactor 112 for the target storage battery group 111. Second, regarding whether or not parallel connection between boxes can be achieved using contactors, this can be achieved by closing both the positive and negative sides of each group contactor 112 for all storage battery groups 111 within the box.

Third, regarding whether or not it is possible to individually adjust the voltage of the in-box battery groups 111, this can be achieved by closing both the P-side and N-side group contactors 112 connected in series with the target battery group 111, and opening at least one of the P-side and N-side group contactors 112 connected in series with the non-target battery groups 111. Fourth, regarding whether or not it is possible to separately perform parallel connection of the in-box battery groups 111 and inter-box parallel connection, this is not possible because closing the P-side and N-side group contactors 112 connects the battery groups 111 in parallel and connects the battery box 101 to the battery system 100.

In a limited sense, this is possible if all the contactors of the other battery boxes 101 are open, but this is not general to the contactor states of the other battery boxes 101. Fifth, whether the external connection terminals 101P, 101N of the battery boxes can be put into a power outage state can be achieved by opening all of the group contactors 112. Sixth, whether the ground fault current can be interrupted can be achieved by opening each group box contactor 112 on the N side. Seventh, the number of contactors in a box [pieces/box] is 2N [pieces/box], where N is the number of battery groups 111.

12 is a circuit diagram showing a battery box 101c having a circuit configuration according to a modification of Example 1. Each group contactor 112 is installed for each battery group 111 on the N-side of the battery group 111 and on the P-side of the N-side connection point 115N of the battery group 111, and each box contactor 113 is installed for each battery box 101 on the N-side of the battery group 111 and on the P-side of the N-side terminal 101N of the battery box 101.

The features of this circuit configuration will be explained one by one for No. 1 to No. 7 in Figure 14. First, regarding whether or not parallel connection between storage battery groups 111 within a box can be achieved using contactors, this can be achieved by closing each target group contactor 112. Second, regarding whether or not parallel connection between boxes can be achieved using contactors, this can be achieved by closing all group contactors 112 and box contactors 113 within the box.

Third, whether or not the voltage of each in-box battery group 111 can be adjusted individually can be achieved by closing each group contactor 112 and each box contactor 113 connected in series to the target battery group 111, and opening each group contactor 112 connected in series to the non-target battery group 111. Fourth, whether or not the parallel connection of the in-box battery groups 111 and the inter-box parallel connection can be achieved separately can be achieved by closing each group contactor 112 for the battery group 111, and by closing each box contactor 113 for the inter-box connection.

Fifth, it is not possible to put the external connection terminals 101P and 101N of the battery box into a power outage state. Sixth, it is possible to interrupt the ground fault current by opening each box contactor 113. Seventh, the number of contactors in a box is N+1 (units/box), where N is the number of storage battery groups 111.

13 is a circuit diagram showing a battery box 101d having a circuit configuration according to a modification of Example 1. Each group contactor 112 is installed for each battery group 111, except for one, on the north side of the battery group 111 and on the north side of the battery group 111 N-side connection point 115N, and each box contactor 113 is installed for each battery box 101 on the north side of the battery group 111 N-side connection point 115N and on the north side of the battery box 101 N terminal 101N.

The features of this circuit configuration will be explained one by one for No. 1 to No. 7 in Figure 14. First, regarding whether or not parallel connection between storage battery groups 111 within a box can be achieved using contactors, this can be achieved by closing each group contactor 112. However, even if there are three or more storage battery groups 111, storage battery groups 111 without a group contactor 12 will always be connected in parallel at the same time. Second, regarding whether or not parallel connection between boxes can be achieved using contactors, this can be achieved by closing all group contactors 112 and box contactors 113 within the box.

Third, regarding whether or not it is possible to individually adjust the voltage of the in-box battery groups 111, this is not possible because the battery groups 111 without the group contactors 12 are always connected. Fourth, regarding whether or not it is possible to separately connect the in-box battery groups 111 in parallel and between boxes, this is possible by closing the group contactors 112 for the battery groups 111, and by closing the box contactors 113 for the between boxes.

Fifth, the external connection terminals 101P and 101N of the battery box cannot be put into a power outage state by the battery box 101P. Sixth, the ground fault current can be interrupted by opening each box contactor 113. Seventh, the number of contactors in a box is N [units/box], where N is the number of storage battery groups 111.

As described above, the battery box 101 in Fig. 4 can have all of the functions No. 1 to No. 6 while keeping the number of contactors to a small number (N+1 per box). In particular, it has a contactor on both the positive and negative sides of all of the battery groups 111, making it possible to separately connect the intra-box battery groups 111 in parallel and connect the boxes in parallel, which is not possible with the battery box 101b, which has a large number of contactors.

From the above, the advantages of the present invention are, first, reduction in the cost and installation space of contactors. Second, the voltage of any battery group 111 and battery box 101 in the battery system can be adjusted individually, enabling automatic parallelization under voltage conditions that cause any cross current. Third, even if a vehicle interrupts driving during voltage adjustment to suppress cross current, the voltage adjustment within the box is completed early, so by using the battery boxes 101 in order starting with the higher voltage, the capacity of the battery system can be maximized and the driving distance can be ensured.

In Example 1, each group contactor 112 and each box contactor 113 is a single-pole product with one contact and switching mechanism, and all contactors are capable of operating independently. In contrast, Example 2 considers a case in which the contactors have multiple contacts, and all contacts open and close simultaneously. Example 2, shown in Figure 15 onwards, is considered more suitable for actual manufacturing. One reason for this is that, in terms of the number of interlocking opening and closing contacts of the contactor, a three-contact simultaneous opening and closing type is an existing product that is easy to procure for three-phase simultaneous opening and closing.

Figure 15 is a diagram showing the configuration of a multi-pole contactor 116 according to a second embodiment of the present invention. The multi-pole contactor has multiple contacts 116a and one opening/closing mechanism 116b that opens and closes them. The opening/closing mechanism 116b typically uses a spring to open the contacts and an energized electromagnet to close them. To individually operate the multiple contacts 116a of the multi-pole contactor, it is necessary to install multiple opening/closing mechanisms 116b.

Multi-pole contactors, in which one switching mechanism 116b opens and closes multiple contacts, are available on the market. Even for applications involving large currents, two-pole products that open and close both PN ends of an electrical circuit, and three-pole products for three-phase AC, are available at low cost. Using a multi-pole contactor allows for a smaller, less expensive contactor configuration than using single-pole contactors to cover the same number of contacts in a battery box.

Figure 16 is a circuit diagram of a railway vehicle battery system 199 according to a second embodiment of the present invention. The contacts 116a of the multi-pole contactor 116 in Figure 15 are divided into group contacts 112a, one for each battery group 111, and box contacts 113b, one for each battery box 101, according to their connection positions on the circuit. The group contacts 112a are located in the same position on the circuit as the group contactors 112 in the first embodiment, and the group contacts 112b are located in the same position as the box contactors 113 in the first embodiment. With this configuration, charging and discharging of each battery group 111 cannot be performed individually.

Figure 17 is a block diagram showing a paralleling control system 299 applied to the present battery storage system 199 of Figure 16. Compared to the paralleling control system 200 of Example 1 shown in Figure 5, the paralleling control system 299 differs in that the in-box contactor control unit 207 transmits contactor opening/closing operations to one multi-pole contactor 116.

Figure 18 is a flowchart 300 showing the first half of the procedure for paralleling control by the battery system 199 of Figure 16. Figure 19 is a flowchart 300 showing the second half of the procedure for paralleling control of Figure 18. Example 2 shown in Figures 18 and 19 differs from the flowchart 300 for Example 1 shown in Figure 6 because it uses a multi-pole contactor 116. Each step will be explained in order. In start step U1, the paralleling control flowchart 300 begins. At this time, the battery electric train traction system 1A is in the off state, and all group contactors 112 and all box contactors 113 are in the open state.

In vehicle system on determination step U2, the vehicle control device 13 determines whether the vehicle system key is on. If it is on, proceed to the next step; if it is off, return to S2. In battery status analysis step U3, the battery box control boards 205 in all boxes analyze the battery status (each group resistance, each group voltage, cell resistance, cell voltage) and battery abnormality determination for each battery box 101 and send the results to the vehicle control device 13.

In target box selection step U4, the battery box control board 205 selects a target box i for paralleling the storage battery groups 111 within the box. In inter-group cross current calculation step U5, the cross current calculation unit 208 calculates the cross current value when each group contactor 112 in the battery box 101 is closed, and determines whether the inter-group cross current value is small and safe paralleling is possible. Due to the operation of the multi-pole contactor 116, if there are three or more storage battery groups 111, the cross current when all storage battery groups 111 are connected in parallel at the same time is calculated.

In step U6, if the battery box control board 205 determines that the inter-group voltages match in step U5, it proceeds to step U7, where it determines whether all box inter-group voltage adjustments have been completed. If the voltages do not match, it proceeds to step U8, where it determines whether the inter-group voltage safety value is determined. "Voltage agreement" means that the voltages are below a threshold below which the occurrence of cross currents can be ignored. In step U7, the paralleling control unit 210 determines whether all box inter-group voltage adjustments have been completed.

If the cross current calculation unit 208 determines in inter-group cross current safety value determination step U8 that the cross current value is too large to adjust the voltage, this is also counted as completed. If completed, proceed to inter-box cross current calculation step U12; if not completed, proceed to inter-group cross current safety value determination step U8. In inter-group cross current safety value determination step U8, the cross current calculation unit 208 determines whether the inter-group cross current is within the safe value even if the multi-pole contactor 116 is closed, even if it is determined that the inter-group voltages are inconsistent in inter-group voltage agreement determination step U6.

If it is within the safety value, the process proceeds to step U9 for closing the multi-pole contactor, and if it is greater than the safety value, the process proceeds to step U7 for determining whether or not voltage adjustment between all boxes has been completed. In step U9 for closing the multi-pole contactor, the box internal contactor control unit 207 closes the multi-pole contactor 116 of box i. At this time, the box internal contactor control unit 207 connects all storage battery groups 111 in box i in parallel. Meanwhile, the multi-pole contactors 116 other than those of box i are in the open state, so no cross current flows between the boxes.

In voltage equalization waiting step U10, a cross current flows between the storage battery groups 111 inside box i, and the cross current causes the charge rates of the high-voltage storage battery groups 111 to decrease, while conversely, the charge rates of the low-voltage storage battery groups 111 to increase, causing the parallelization control unit 210 to wait until the open-circuit voltages become equal. The wait continues, for example, until the current flowing through the current sensor 203 becomes equal to or less than a threshold value.

In the multi-pole contactor opening step U11, the intra-box contactor control unit 207 opens the multi-pole contactor 116 of box i. This prevents cross currents from occurring between boxes, even when voltage adjustment is performed in the next battery box 101. In the box-to-box cross current calculation step U12, the cross current calculation unit 208 calculates the cross current value when the multi-pole contactor 116 in the battery pack is closed, and determines whether the cross current value between boxes is small and safe for parallelization. If there are three or more battery boxes 101, the cross current calculation unit 208 calculates the cross current value when parallelization is performed from the low-voltage side.

19 , in step U13 for determining a safe inter-box cross current value, if step U12 for calculating the inter-box cross current determines that the inter-box cross current value is small and therefore safe parallel connection is possible, the process proceeds to step S20 for closing each box contactor, whereas if step U12 determines that the inter-box cross current value is large and therefore safe parallel connection is not possible, the process proceeds to step U15 for determining whether traveling is interrupted and step U23 for determining whether inter-box voltage adjustment is complete for adjusting the inter-box voltage. In Example 2, because there is no means for individually charging the battery groups 111, battery boxes 101 for which it is determined at this stage that parallel connection between the battery groups 111 is not possible cannot be used under automatic control, and it is necessary to manually connect the battery groups 111 individually to a charge/discharge circuit and adjust the voltage.

In step U14, the multi-pole contactors are closed, and the battery boxes 101 are connected in parallel, based on the contactor closure determination calculated by the cross current calculation unit 208, within a range where the inter-box cross current value is small and safe parallel connection is possible. In step U15, as the first step in inter-box voltage adjustment, if the parallel control unit 210 of the vehicle control device 13 receives a running cut-in command from the cab 12, the inter-box voltage adjustment is interrupted and the process proceeds to step T1 in the running cut-in control flowchart 400 of Figure 7.

The reason there is no running interruption determination step in the inter-group voltage adjustment from inter-group cross current safety value determination step U8 to multi-pole contactor open step U11 is because there is no voltage adjustment due to charging/discharging on a group-by-group basis, and therefore no operations requiring interruption. In target box selection step U16, target box i for paralleling the battery boxes 101 in the battery system is selected. The order of i can be arbitrary, but it is preferable to select boxes for which a battery abnormality or contactor abnormality has been determined to have occurred later.

In the chargeability status determination step U17, the vehicle status indicating whether charging is possible or not is determined according to the contact status of the pantograph 2 with the overhead wire, and a decision is made as to whether voltage adjustment should be performed by charging or discharging, and the voltage adjustment target value calculation unit 209 calculates the voltage adjustment target value. In the charging box connection step U18, if the target battery box i has a voltage lower than the voltage adjustment target value and requires charging, the multi-pole contactor 116 corresponding to the target battery box i is closed, connecting it to the battery train traction system 1A and making it available for charging. If the target battery box i has a voltage higher than the voltage adjustment target value and does not require charging, the process proceeds to the next step.

In the battery box charging step U19, if the target battery box i has a voltage lower than the voltage adjustment target value and requires charging, the converter 5 is activated and the target battery box i is charged to the voltage adjustment target value. If the target battery box i has a voltage higher than the voltage adjustment target value and does not require charging, proceed to the next step. In the discharge box connection step U20, if the target battery box i has a voltage higher than the voltage adjustment target value and requires discharging, the box contactor control unit 207 closes the multi-pole contactor 116 corresponding to the target battery box i, connecting it to the battery train traction system 1A and enabling discharging. If the target battery box i has a voltage lower than the voltage adjustment target value and does not require discharging, proceed to the next step.

In the battery box discharge step U21, if the target battery box i has a higher voltage than the voltage adjustment target value and requires discharging, the paralleling control unit 210 starts the auxiliary inverter 10 and discharges the target battery box i to the voltage adjustment target value. If the target battery box i has a lower voltage than the voltage adjustment target value and does not require discharging, the process proceeds to the next step. In the multi-pole contactor opening step U22, the box contactor control unit 207 opens the multi-pole contactor 116 of the battery box 101i. This is to isolate the battery box 101i from the battery electric train traction system 1A and prevent cross currents from flowing between the battery boxes 101i and 101i+1 when adjusting the voltage of the next battery box 101i+1.

In step U23, which determines whether voltage adjustment between boxes is complete, the paralleling control unit 210 determines whether voltage adjustment is complete in all battery boxes 101. If not, the process returns to step U16, where the next battery box (i+1) is selected as the target battery box for voltage adjustment, and the voltage adjustment process within the box is repeated. If voltage adjustment is complete in all battery boxes 101, the process proceeds to step U14, where all multi-pole contactors are closed. In step U24, the paralleling process is completed, and the battery system 199 is connected to the battery train traction system 1A and is ready for battery travel.

Figure 20 is a table comparing the effects of battery boxes 101a, 101b, 101c, and 101d of modified examples a to d with the battery box 101 of Figure 16. This table compares the effects of battery boxes 101a, 101b, 101c, and 101d of modified examples shown in Figures 10 to 13 with the battery box 101 of Example 2 shown in Figure 16. In Example 2, the contacts of all contactors 112a and 113a in box 101 are multi-pole contactors that open and close simultaneously. The only differences between Figure 19 and the modified example of Example 1 shown in Figure 14 are the items shown in rows 3 and 4; the rest are the same.

Regarding the third item (No. 3), whether or not it is possible to individually adjust the voltage of each in-box battery group 111, this is not possible in all circuit configurations because the contacts 112a of each battery group 111 in the multi-polar contactor operate simultaneously within the box. Regarding the fourth item (No. 4), whether or not it is possible to separately connect the in-box battery groups 111 in parallel and between boxes, this is generally not possible because the contacts 112a of each battery group 111 and the contacts 113a of each box in the multi-polar contactor operate simultaneously, but it is possible in limited cases if all the contactors of the other battery boxes 101 are open.

As described above, even in Example 2, which uses multi-pole contactors, the battery box 101 in FIG. 4 can keep the number of contactors to a small number (N+1 per box) and still perform the functions of Nos. 1, 2 to 4, and 6. Function No. 3 can also be achieved by opening the contactors in the other boxes. Having contactors on both the positive and negative sides of all battery groups 111, it is possible to achieve the same effect as battery box 101b, which has a large number of contactors, while reducing the number of contacts.

However, in Example 2, since there is no means for individually charging the storage battery groups 111, the storage battery boxes 101 that are determined to be unable to be connected in parallel between the storage battery groups 111 cannot be used under automatic control, and it is necessary to manually connect the storage battery groups 111 individually to the charge/discharge circuit and adjust the voltage.

The above-described railway vehicle storage battery systems 100 and 199 require a larger number of batteries than automobiles. The storage batteries are housed inside the battery box 101 in the form of a battery module ( storage battery group 111) in which a plurality of single battery cells are packaged, and the series-connected storage battery groups 111 are further connected in parallel to meet the performance requirements of the railway vehicle.

In order to increase the maximum current value and charge capacity of the battery pack, it is necessary to increase the number of parallel connections of the storage battery groups 111, and multiple storage battery groups 111 are connected in parallel within the box, and multiple storage battery boxes 101 are also connected in parallel. A contactor is disposed within the storage battery box 101 to connect or disconnect the storage battery box 101 to a peripheral circuit. For example, the contactor is disconnected (opened) when the vehicle system is off, and connected (closed) when the vehicle system is on.

In the above-described embodiment, a storage battery system mounted on a railway vehicle was illustrated, but its use is not limited to railway vehicles. The technical concept of the present invention can also be applied to storage battery systems in various other systems, including stationary systems. Furthermore, in the above-described embodiment, lithium-ion batteries were used as the storage batteries that make up the power storage device, but the present invention can also be applied to other storage elements, such as lead batteries, nickel-metal hydride batteries, or capacitors.

The storage battery system 100 can be summarized as follows.
[1] The battery system 100 shown in Figures 2 to 5 includes a battery pack, a charging device (converter 5) and a discharging device (auxiliary inverter 10) for the battery pack, group switching devices 112 for each group arranged in a battery box 101, and a paralleling control unit 210. The battery pack has one or more battery boxes 101 and mainly constitutes the battery system 100.

The battery box 101 houses a plurality of battery groups 111 connected in parallel. The parallelization control unit 210 maintains each of the plurality of battery groups 111 at an equal voltage. A group opening/closing device 112 is connected in series to at least one pole (e.g., positive pole) of each of the battery groups 111 for each group. The opposite negative poles of each of the plurality of battery groups 111 are connected in parallel to a connection point 115N. One box opening/closing device 113 is connected in series to the connection point 115N.

The parallelization control unit 210 connects the battery groups 111 in the battery boxes 101 in parallel by closing each of the group opening/closing devices 112 connected in series for each group. In other words, the parallelization control unit 210 connects the battery boxes 101 in the assembled battery in parallel by closing all of the group opening/closing devices 112 and the box opening/closing devices 113.

The present battery system 100 can reduce the total number of contactors 112, 113 that control cross current when multiple battery boxes 101, each having multiple battery groups 111 inside, are connected in parallel. In other words, the number of switchgears required in conventional systems is one for each group and each pole. In contrast, as shown in Figure 4, the present battery system 100 reduces the number of contactors from four to three for two groups and one box, and from six to four for three groups and one box.

Despite this simplification, the battery system 100 allows for consideration of preventing danger (remote operation) associated with battery replacement work, while also reducing the total number of group opening/closing devices 112 and box opening/closing devices 113. Mainly during a maintenance stop, immediately after replacing only some of the deteriorated battery groups 111, the system can achieve the minimum number of switches necessary to reduce cross currents and equalize the voltage differences between the boxes in each group.

[2] In the above [1] shown in Figure 4, when a specific battery group 111 is connected to the assembled battery for charging or discharging, the parallelization control unit 210 closes the group switchgear 112 connected in series with the specific battery group 111, closes the box switchgear 113 of the battery box 101 that has the specific battery group 111, opens the other group switchgears 112 of the battery box 101 that has the specific battery group 111, and opens the box switchgears 113 of the battery boxes 101 other than the battery box 101 that has the specific battery group 111. This battery system 100 can eliminate differences in charging rate or voltage that can cause cross current by separately charging and discharging the specific battery group 111 and the battery boxes 101 that contain it. This is particularly convenient for improving the efficiency of replacing only some depleted battery groups 111 during maintenance stops.

[3] As shown in Figures 6 to 9, in the above [1], the parallelization control unit 210 calculates, as a calculated current value, a current value generated from the voltage difference between the storage battery groups 111 connected in parallel within the storage battery box 101, and when the calculated current value exceeds a safety threshold and voltage adjustment is necessary, determines whether the assembled battery is in a chargeable state or not, and when chargeable, charges the low-voltage storage battery group 111 to the voltage of the highest-voltage storage battery group 111, and when chargeable, discharges the high-voltage storage battery group 111 to the voltage of the lowest-voltage storage battery group 111.

In other words, when the battery system 100 is connected to an overhead line and charging is possible, it controls parallelization by charging in a direction that aligns low voltage with high voltage. Conversely, when the battery system 100 is not connected to an overhead line, it determines that charging is not possible and controls parallelization by discharging in a direction that aligns high voltage with low voltage. Therefore, the battery system 100 is suitable not only for battery-powered electric trains but also for hybrid diesel railcars. The battery system 100 can achieve parallel connection of multiple battery groups 111 and one or more battery boxes 101, regardless of their respective voltage values, by automatically adjusting the voltage to avoid excessive cross currents.

[4] In the above [1], the parallelization control unit 210 calculates the current value generated from the voltage difference between the parallel-connected battery boxes 101, and when the calculated current value exceeds a safety threshold and voltage adjustment is necessary, determines whether the assembled battery is in a chargeable state. If chargeable, it charges the lower-voltage battery box 101 to the voltage of the highest-voltage battery box 101, and if chargeable, it discharges the higher-voltage battery box 101 to the voltage of the lowest-voltage battery box 101. This battery system 100 is configured to suppress cross currents on a battery box 101-by-battery box basis, and is easy to design, manufacture, and maintain as an actual on-board device.

6, 18, and 19, in the battery system 100 of [3] and [4] above, if the cross current value when connecting battery groups 111 or battery boxes 101 in parallel exceeds a safety threshold, each group contactor 112 and each box contactor 113 are individually operated to connect the battery group 111 or battery box 101 to be voltage-adjusted to an external circuit, and voltage is adjusted by charging or discharging. The battery system 100 applied to railway vehicles reduces cross current and equalizes voltage, so that specific switching control can be reliably implemented, including running cut-in and discharging to auxiliary equipment as a countermeasure against overvoltage due to regenerative power.

[5] In the above [3] or [4], the parallelization control unit 210 first adjusts the voltages of the battery groups 111 in all of the battery boxes 101 and connects them in parallel, and then adjusts the voltages of the battery boxes 101 in the entire battery pack and connects them in parallel. In the case of a battery train, even if it takes about 10 minutes to control the parallelization of the entire battery pack, if just one of the multiple battery boxes 101 can complete parallelization in a short time and function effectively, it can still be powered, making it easier to maintain availability. In other words, if the voltages of the battery groups 111 in all of the battery boxes 101 are adjusted first, then only the battery box 101 whose voltage adjustment was completed earliest can be selected for use, even if the adjustments are not completed simultaneously.

[6] As shown in Figures 5 and 17, in the above [3] or [4], if the paralleling control unit 210 receives a running command from the cab 12 during voltage adjustment, it suspends voltage adjustment and simultaneously closes all of the switchgears directly connected to the parallel-connectable storage battery groups 111. With this storage battery system 100, only the parallel-connectable storage battery groups 111 can be selectively connected for power running, which reduces the risk of stranding even in an emergency.

[7] As shown in Figure 9, in [6] above, the paralleling control unit 210 first connects the battery box 101 with the highest voltage to the battery pack. If the voltage of the connected battery box 101 drops during travel and becomes the same as that of the disconnected battery box 101, the disconnected battery box 101 is newly connected to the battery pack. In a battery-powered train that is discharging battery power due to a lack of power supply from the overhead lines, this battery system 100, which has a mixture of usable and unusable battery boxes, sequentially connects and incorporates battery boxes that have become usable as the voltage difference disappears, thereby maximizing the cruising range.

[8] In the above [3], the parallelization control unit 210 selects the storage battery group 111 to be subjected to voltage adjustment in order of the amount of charge/discharge required for voltage adjustment, starting with the battery group 111 having the least amount of charge/discharge required for voltage adjustment. A vehicle incorporating this storage battery system 100 can achieve rational and optimal parallelization control to ensure that the vehicle can run in an emergency.

[9] In the above [3] or [4], the paralleling control unit 210 selects the battery boxes 101 or battery groups 111 to be subjected to voltage adjustment from among those for which neither a battery abnormality nor a switching device abnormality has been determined. A vehicle to which this battery system 100 is applied can achieve rational and optimal control to enable the vehicle to run even if there is a mixture of usable and unusable battery packs in a redundant configuration, making it easier to operate according to the schedule and maintaining availability.

[10] As shown in Figures 5, 8, 9, and 17, in the above [3] or [4], the paralleling control unit 210 transmits information including at least one of the open/close status of the contactors in the battery pack, the voltage of each storage battery group 111, the voltage of each storage battery box 101, the remaining voltage adjustment time, the cruising range, and the maximum acceleration force to the cab 12, and displays the information on a monitor disposed in the cab 12. A vehicle employing such a storage battery system 100 can reduce the burden of storage battery control on the driver.

[11] As shown in Figures 8 and 9, in [10] above, the information displayed on the monitor further includes at least one of the contactor open/close status, cruising range, and acceleration force when voltage adjustment continues from the current time and a running command is issued in the future. A vehicle equipped with this battery storage system 100 displays the vehicle's status to the driver waiting to depart, providing peace of mind and security.

[12] In the above [11], the information displayed on the monitor is the value at the time when the battery boxes 101 are paralleled, and is used to calculate the cruising range from the time when the vehicle starts traveling during voltage adjustment. A vehicle equipped with this battery storage system 100 can reduce the burden on the driver of managing the remaining battery capacity. Note that while paralleling control in an actual vehicle is often performed primarily in units of battery boxes 101, it can also be performed in units of battery groups 111.

[13] In [10] above, the information displayed on the monitor is used to determine whether or not a specified point on the route can be reached. Vehicles equipped with this battery storage system 100 not only find it easier to escape from tunnels, bridges, dead sections, etc., but also have a higher reliability in determining whether or not the vehicle can reach a station.

[14] As shown in Figure 15, in [4] above, all of the switchgears provided in the storage battery group 111 and each of the box switchgears share a single box-shared switching mechanism and can simultaneously open and close. Such contactors 112, 113 are highly reliable, easily procured, and well-known off-the-shelf products that can be used for single-phase bipolar switching as well as three-phase circuits. The storage battery system 100 using such contactors is easy to design, manufacture, and maintain, and has high practicality.

[15] As shown in Figures 6, 7, 18, and 19, in the battery system [14] above, the battery box 101 in which all of the battery groups 111 in the box are to be connected in parallel within the battery pack is designated as the battery box 101. The parallelization control unit 210 calculates the current value generated from the voltage difference between all of the battery groups 111 connected in parallel simultaneously within the battery box 101, and if the calculated current value is within a safety threshold and parallel connection is possible, the box-shared opening/closing mechanism of the battery box 101 is closed and the box-shared opening/closing mechanism of the boxes other than the battery box 101 is opened, thereby isolating the parallel connection of the battery groups 111 in the battery box 101 from the battery boxes 101 other than the battery box 101. This battery system 100 can achieve rational and optimal parallelization control.

The railway vehicle battery control method (the present method) according to the embodiment of the present invention can be summarized as follows.
[16] As shown in FIGS. 2 to 7 , 18 and 19 , in this method, a parallelization control unit 210 controls the parallelization of a battery pack formed by one or more battery boxes 101, each storing a plurality of parallel-connected battery groups 111, so as to maintain the voltages of the plurality of battery groups 111 at equal levels.

The paralleling control involves controlling the opening and closing of the group opening/closing devices 112 for each group that are connected in series to at least one pole of each storage battery group 111 in the storage battery box 101. In this method, one box opening/closing device 113 is used that is connected in series to a connection point 115N where each of the multiple storage battery groups 111 is connected in parallel, at the opposite (e.g., negative) pole to the (e.g., positive) pole to which each group opening/closing device 112 is connected in series.

Furthermore, by closing each group switchgear 112, the paralleling control unit 210 can connect the battery groups 111 in parallel only within the battery box 101. Furthermore, by closing the box switchgear 113 in addition to each group switchgear 112, the paralleling control unit 210 can connect the closed battery box 101 in parallel within the assembled battery. This method minimizes the number of contactors 112, 113 required to suppress cross current between battery groups 111 or between battery boxes 101. Furthermore, specific battery groups 111 that require charging/discharging for paralleling control can be safely detached from the assembled battery. In other words, a deteriorated battery group 111 can be safely replaced while preventing risks such as arc generation due to cross current.

1A... Battery electric train drive system, 1B... Hybrid diesel railcar drive system (this hybrid drive system), 2... Pantograph, 3... Engine, 4... Generator, 5... Converter, 6... Motor inverter, 7... Motor, 8... Reducer, 9... Wheelset, 10... Auxiliary equipment inverter, 11... Auxiliary equipment, 12... Driver's cab 12, 13... Vehicle control device, 14... Overhead line, 15... Earth, 100... Railway vehicle battery system (assembled battery), 100 P... battery system P terminal, 100N... battery system N terminal, 101, 101a, 101b, 101c, 101d... battery boxes, 101P... battery box P terminal, 101N... battery box N terminal, 111... battery group, 112... each group contactor, 112a... each group contact, 113... each box contactor, 113a... each box contact, 114... service connector, 115P... battery group P side connection point, 115N... battery group N side connection point, 116... multi-pole contact contactor, 116a...contact, 116b...opening/closing mechanism, 200, 299...parallelization control system, 201...battery module, 202...cell control board, 203...current sensor, 204...voltage sensor, 205...battery box control board, 206...battery state analysis unit, 207...in-box contactor control unit, 208...cross current calculation unit, 209...voltage adjustment target value calculation unit, 210...parallelization control unit, 300...parallelization control flowchart, 400...travel interruption flowchart , S1... start step, S2... vehicle system on determination step, S3... battery state analysis step, S4... target box selection step, S5... inter-group cross flow calculation step, S6... inter-group cross flow safety determination step, S7... each group contactor closing step, S8... travel cut-in determination step, S9... target group selection step, S10... chargeable status determination step, S11... charging group connection step, S12... storage battery group charging step, S13... discharging group connection step S14... step of discharging the storage battery groups, S15... step of determining completion of inter-group voltage adjustment, S16... step of opening the contactors of each box, S17... step of determining completion of inter-group voltage adjustment for all boxes, S18... step of calculating cross current between boxes, S19... step of determining safety of cross current between boxes, S20... step of closing the contactors of each box, S21... step of determining whether to interrupt the drive, S22... step of selecting the target box, S23... step of determining whether charge is possible, S24... step of connecting the charging box, S25... step of charging the battery box, S26... step of connecting the discharging box, S27... step of discharging the battery box, S28... step of opening the contactors of each box, S29... step of determining completion of inter-box voltage adjustment, S30... step of terminating, T1... step of starting the drive to interrupt, T2... step of determining whether a battery box can be used, T3... step of connecting the box with the highest voltage, T4... step of driving, T5... step of matching box voltages, T6... step of closing the contactors of each box, T7... step of determining whether all boxes are parallelized, T8... step of terminating end step, U1...start step, U2...vehicle system on determination step, U3...battery state analysis step, U4...target box selection step, U5...inter-group cross current calculation step, U6...inter-group voltage agreement determination step, U7...all-box inter-group voltage adjustment completion determination step, U8...inter-group cross current safety value determination step, U9...multi-pole contactor closing step, U10...voltage leveling waiting step, U11...multi-pole contactor opening step, U12...inter-box cross current calculation step, U13...inter-box cross current safety value determination step, U14...all multi-pole contactor closing step, U15...travel interrupt determination step, U16...target box selection step, U17...chargeable status determination step, U18...charging box connection step, U19...battery box charging step, U20...discharging box connection step, U21...battery box discharging step, U22...multi-pole contactor opening step, U23...inter-box voltage adjustment completion determination step, U24...end step

Claims (30)

one or more battery boxes containing a plurality of parallel-connected battery groups;
a parallelization control unit that maintains each of the plurality of storage battery groups at an equal voltage;
Disposed in the battery box,
a group switchgear for each of the storage battery groups connected in series to at least one pole of each of the storage battery groups;
In a battery system for railway vehicles that comprises a battery pack,
each of the group switching devices has one box switching device connected in series to a connection point where the plurality of storage battery groups are connected in parallel, with the polarity opposite to that of the series-connected polarity;
the parallelization control unit connects the battery groups in the battery boxes in parallel by closing each of the group opening/closing devices, and connects the battery boxes in parallel by closing each of the group opening/closing devices and the box opening/closing device.
Battery storage system for railway vehicles. The parallelization control unit
When a specific storage battery group is connected to the assembled battery for charging or discharging,
closing the group switchgear connected in series to the specific storage battery group;
closing the box opening/closing device of the battery box having the specific battery group;
opening the other group opening/closing devices of the battery box having the specific battery group;
opening the box opening/closing devices of the battery boxes other than the battery box having the specific battery group;
The railway vehicle battery system according to claim 1 . The parallelization control unit
a current value generated from a voltage difference between the battery groups connected in parallel in the battery box is calculated as a calculated current value;
determining whether the battery pack is in a chargeable state when the calculated current value exceeds a safety threshold and voltage adjustment is required;
If chargeable, charging the battery group with the lower voltage to the voltage of the battery group with the highest voltage;
If charging is not possible, the high-voltage storage battery group is discharged to the voltage of the lowest-voltage storage battery group.
The railway vehicle battery system according to claim 1 . The parallelization control unit
Calculating a current value generated from a voltage difference between the parallel-connected battery boxes;
When the current value exceeds a safety threshold and voltage adjustment is required, it is determined whether the battery pack is in a chargeable state;
If rechargeable, charge the battery box with the lower voltage to the voltage of the battery box with the highest voltage;
If charging is not possible, the high-voltage battery box is discharged to the voltage of the lowest-voltage battery box.
The railway vehicle battery system according to claim 1 . The parallelization control unit
First, the voltages of the storage batteries in all the storage battery boxes are adjusted and connected in parallel,
The battery boxes of the entire battery pack are connected in parallel with voltage adjustment.
5. The railway vehicle battery system according to claim 3 or 4. The parallelization control unit
If a running command is received from the cab during the voltage adjustment,
and simultaneously suspending the voltage adjustment, closing all of the switchgears directly connected to the storage battery group that can be connected in parallel.
5. The railway vehicle battery system according to claim 3 or 4. The parallelization control unit
First, connect the battery box with the highest voltage to the battery pack;
If the voltage of the connected battery box drops while driving and becomes the same as that of the unconnected battery box,
The disconnected battery box is newly connected to the battery pack.
The railway vehicle battery system according to claim 6. The parallelization control unit
The storage battery group to be subjected to the voltage adjustment is
The charge/discharge amount required for the voltage adjustment is selected in ascending order.
The railway vehicle battery system according to claim 3 . The parallelization control unit
The battery box or the battery group to be subjected to the voltage adjustment,
Select from those for which no battery abnormality or switching device abnormality has occurred.
5. The railway vehicle battery system according to claim 3 or 4. The parallelization control unit
transmitting information including at least one of the open/close status of the contactors in the battery pack, the voltage of each battery group, the voltage of each battery box, the remaining time for voltage regulation, the cruising range, and the maximum acceleration force to the driver's cab;
The information is displayed on a monitor disposed in the driver's cab.
5. The railway vehicle battery system according to claim 3 or 4. The information further includes at least one of a contactor open/close status, a cruising range, and an acceleration force when the voltage adjustment is continued from the current time and a driving command is issued at a future time.
The railway vehicle battery system according to claim 10. The information is a value at the time when the battery boxes are connected in parallel, and is used to calculate the cruising range from the time when the vehicle starts traveling during the voltage adjustment.
The railway vehicle battery system according to claim 11. The information is used to determine whether or not a predetermined point on the route can be reached.
The railway vehicle battery system according to claim 10. All of the opening and closing devices provided in the storage battery group and each of the box opening and closing devices share one box-shared opening and closing operation mechanism and can open and close simultaneously.
The railway vehicle battery system according to claim 4. A battery box in which all of the storage batteries in the box are to be connected in parallel within the battery pack is defined as a battery box,
the parallelization control unit calculates a current value generated from a voltage difference between all of the storage battery groups simultaneously connected in parallel in the storage battery box,
If the current value is within a safety threshold and parallel connection is possible,
The opening/closing mechanism shared by the battery box is closed, and the opening/closing mechanism shared by boxes other than the battery box is opened.
The parallel connection of the battery group in the battery box is separated from the battery boxes other than the battery box.
The railway vehicle battery system according to claim 14. One or more battery boxes each containing a group of parallel-connected storage batteries are connected in parallel to form a battery pack;
In order for the parallelization control unit to perform parallelization control so as to maintain the voltages of the plurality of storage battery groups uniform,
In the battery box, group switchgears for each group connected in series to at least one pole of each of the battery groups are controlled to open and close.
A method for controlling a storage battery for a railway vehicle, comprising:
a pole opposite to the pole at which each of the group switchgears is connected in series is set as a connection point at which the plurality of storage battery groups are connected in parallel,
Each box opening/closing device is connected in series to the connection point,
the parallelization control unit connects the battery groups in the battery boxes in parallel by closing each of the group opening/closing devices, and connects the battery boxes in parallel by closing each of the group opening/closing devices and the box opening/closing device.
A method for controlling a battery for a railway vehicle. The parallelization control unit
When a specific storage battery group is connected to the assembled battery for charging or discharging,
closing the group switchgear connected in series to the specific storage battery group;
closing the box opening/closing device of the battery box having the specific battery group;
opening the other group opening/closing devices of the battery box having the specific battery group;
opening the box opening/closing devices of the battery boxes other than the battery box having the specific battery group;
The method for controlling a battery for a railway vehicle according to claim 16. The parallelization control unit
a current value generated from a voltage difference between the battery groups connected in parallel in the battery box is calculated as a current value;
When the current value exceeds a safety threshold and voltage adjustment is required, it is determined whether the battery pack is in a chargeable state;
If chargeable, charging the battery group with the lower voltage to the voltage of the battery group with the highest voltage;
If charging is not possible, the high-voltage storage battery group is discharged to the voltage of the lowest-voltage storage battery group.
The method for controlling a battery for a railway vehicle according to claim 16. The parallelization control unit
Calculating a current value generated from a voltage difference between the parallel-connected battery boxes;
When the current value exceeds a safety threshold and voltage adjustment is required, it is determined whether the battery pack is in a chargeable state;
If rechargeable, charge the battery box with the lower voltage to the voltage of the battery box with the highest voltage;
If charging is not possible, the high-voltage battery box is discharged to the voltage of the lowest-voltage battery box.
19. The method for controlling a battery for a railway vehicle according to claim 18. The parallelization control unit
First, the voltages of the storage batteries in all the storage battery boxes are adjusted and connected in parallel,
The battery boxes of the entire battery pack are connected in parallel with voltage adjustment.
20. A method for controlling a battery for a railway vehicle according to claim 18 or 19. The parallelization control unit
If a running command is received from the cab during the voltage adjustment,
and simultaneously suspending the voltage adjustment, closing all of the switchgears directly connected to the storage battery group that can be connected in parallel.
20. A method for controlling a battery for a railway vehicle according to claim 18 or 19. The parallelization control unit
First, connect the battery box with the highest voltage to the battery pack;
If the voltage of the connected battery box drops while driving and becomes the same as that of the unconnected battery box,
The disconnected battery box is newly connected to the battery pack.
22. The method for controlling a battery for a railway vehicle according to claim 21. The parallelization control unit
The storage battery group to be subjected to the voltage adjustment is
The charge/discharge amount required for the voltage adjustment is selected in ascending order.
19. The method for controlling a battery for a railway vehicle according to claim 18. The parallelization control unit
The battery box or the battery group to be subjected to the voltage adjustment,
Select from those for which no battery abnormality or switching device abnormality has occurred.
20. A method for controlling a battery for a railway vehicle according to claim 18 or 19. The parallelization control unit
transmitting information including at least one of the open/close status of the contactors in the battery pack, the voltage of each battery group, the voltage of each battery box, the remaining time for voltage regulation, the cruising range, and the maximum acceleration force to the driver's cab;
The information is displayed on a monitor disposed in the driver's cab.
20. A method for controlling a battery for a railway vehicle according to claim 18 or 19. The information further includes at least one of a contactor open/close status, a cruising range, and an acceleration force when the voltage adjustment is continued from the current time and a driving command is issued at a future time.
26. The method for controlling a battery for a railway vehicle according to claim 25. The information is a value at the time when the battery boxes are connected in parallel, and is used to calculate the cruising range from the time when the vehicle starts traveling during the voltage adjustment.
27. The method for controlling a battery for a railway vehicle according to claim 26. The information is used to determine whether or not a predetermined point on the route can be reached.
26. The method for controlling a battery for a railway vehicle according to claim 25. All of the opening and closing devices provided in the storage battery group and each of the box opening and closing devices share one box-shared opening and closing operation mechanism and can open and close simultaneously.
20. The method for controlling a battery for a railway vehicle according to claim 19. A battery box in which all of the storage batteries in the box are to be connected in parallel within the battery pack is defined as a battery box,
the parallelization control unit calculates a current value generated from a voltage difference between all of the storage battery groups simultaneously connected in parallel in the storage battery box,
If the current value is within a safety threshold and parallel connection is possible,
The opening/closing mechanism shared by the battery box is closed, and the opening/closing mechanism shared by boxes other than the battery box is opened.
The parallel connection of the battery group in the battery box is separated from the battery boxes other than the battery box.
30. The method for controlling a battery for a railway vehicle according to claim 29.