JP7129291B2 - power system controller - Google Patents

Description

The present invention relates to a control device for a power supply system.

In recent years, electric vehicles such as electric vehicles (EV) or hybrid vehicles (HEV) that have a drive motor as a drive source have been known. A power supply system for an electric vehicle is provided with a power storage device that stores power supplied to a driving motor. Since the output and capacity of a power storage device generally have a trade-off relationship, it may be difficult to achieve both acceleration performance and cruising range of a vehicle with only one power storage device. Therefore, in order to achieve both acceleration performance and cruising range of a vehicle, it has been proposed to use two power storage devices in combination, as disclosed in Patent Document 1, for example.

JP 2015-133859 A

By the way, in a power supply system including two or more power storage devices, one power storage device is connected to a drive motor, and the one power storage device and the other power storage device are connected by a voltage converter (specifically, a DCDC converter). It is conceivable to connect via Accordingly, by controlling the operation of the voltage converter, it is possible to control the power supply between the power storage devices, so it is expected that the power supply in the power supply system will be appropriately controlled.

Here, the power supply system is provided with a power receiving unit capable of receiving power transmitted from a power source external to the electric vehicle (hereinafter also referred to as an external power source), and power supplied from the external power source via the power receiving unit (hereinafter referred to as an external power source). It is conceivable that a power storage device is charged by using the power (also referred to as electric power). In charging the power storage device, the maximum allowable charge power corresponding to the amount of power that can be charged per unit time by the power storage device depends on the remaining capacity of the power storage device. Therefore, in charging using external power, if power supply between power storage devices via voltage converters is not properly controlled, the external power decreases due to changes in the maximum allowable charging power of the power storage devices. It becomes easier to have the need to This makes it difficult to quickly charge the power storage device.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a novel power storage system capable of rapidly charging the power storage devices in a power supply system including two or more power storage devices. Another object of the present invention is to provide an improved control device for a power supply system.

In order to solve the above problems, according to one aspect of the present invention, a first power storage device connected to a driving motor and a second power storage device connected to the first power storage device via a voltage converter are provided. and a power receiving unit connected to the second power storage device and capable of receiving power transmitted from an external power supply, wherein the control device controls the operation of the voltage converter. Thus, a control unit for controlling power supply between the first power storage device and the second power storage device is provided, and the control unit is supplied from the external power supply via the power receiving unit. In the charging using the external power, the external power is used to charge the second power storage device in a state where the supply of power via the voltage converter is stopped, and the maximum allowable power of the second power storage device is charged. A control device for a power supply system is provided, which starts supplying power from the second power storage device to the first power storage device when it is determined that the charged power is lower than the external power.

In the charging, the control unit may supply power from the first power storage device to the second power storage device before stopping power supply via the voltage converter.

In the charging, the control unit may terminate the supply of electric power from the first power storage device to the second power storage device when it is determined that the remaining capacity of the first power storage device is lower than a reference capacity. good.

In the charging, the control unit may control the power supplied from the first power storage device to the second power storage device to power giving priority to the efficiency of the voltage converter.

In the charging, when power is being supplied from the second power storage device to the first power storage device, the control unit divides the external power into the maximum allowable charging power of the second power storage device and the maximum allowable charging power of the second power storage device. You may control below the total with the maximum output of a voltage converter.

The control unit may determine whether or not the maximum allowable charging power of the second power storage device is lower than the external power, based on an index value correlated with the temperature of the second power storage device.

As described above, according to the present invention, in a power supply system including two or more power storage devices, it is possible to quickly charge the power storage devices.

It is a mimetic diagram showing a schematic structure of a power supply system provided with a control device concerning an embodiment of the present invention. It is a block diagram showing an example of functional composition of a control device concerning the embodiment. It is a flowchart which shows an example of the flow of the process which the control part which concerns on the same embodiment performs. FIG. 4 is a diagram schematically showing the flow of power in the power supply system when power is being supplied from the first secondary battery to the second secondary battery in charging using external power; FIG. 4 is a diagram schematically showing the power flow in the power supply system when the supply of power through the voltage converter is stopped in charging using external power; FIG. 5 is a diagram showing the relationship between the second SOC and the maximum allowable charging power of the second secondary battery; FIG. 4 is a diagram schematically showing the flow of power in the power supply system when power is being supplied from the second secondary battery side to the first secondary battery in charging using external power. FIG. 5 is a diagram showing an example of transitions of the first SOC and the second SOC during charging using external power when the power supply control of the embodiment and the power supply control of the reference example are performed.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Configuration of Power Supply System>
First, the configuration of a power supply system 1 including a control device 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

FIG. 1 is a schematic diagram showing a schematic configuration of a power supply system 1. As shown in FIG. FIG. 2 is a block diagram showing an example of the functional configuration of the control device 100. As shown in FIG.

Specifically, the power supply system 1 is a system that is mounted on an electric vehicle such as an electric vehicle (EV) or a hybrid vehicle (HEV) and used to supply electric power to each device in the vehicle. It should be noted that the electric vehicle may be any vehicle provided with a drive motor as a drive source, and includes railway vehicles.

As shown in FIG. 1 , power supply system 1 includes first secondary battery 10 , second secondary battery 20 , power receiving unit 60 , and control device 100 . Further, the power supply system 1 includes a DCDC converter 30 , an inverter 40 , a drive motor 50 , a first battery sensor 71 , a second battery sensor 72 and an outside air temperature sensor 73 . A vehicle equipped with the power supply system 1 runs using a drive motor 50 as a drive source.

In the power supply system 1, the first secondary battery 10 corresponds to an example of a first power storage device according to the present invention. Also, the second secondary battery 20 corresponds to an example of a second power storage device according to the present invention. Also, the DCDC converter 30 corresponds to an example of a voltage converter according to the present invention.

The first secondary battery 10 is a power storage device connected to the drive motor 50 . Specifically, first secondary battery 10 is connected to drive motor 50 via inverter 40 . As the first secondary battery 10, for example, a secondary battery such as a lithium ion battery is used. Note that the first secondary battery 10 is not particularly limited to such an example, and may be another secondary battery such as a nickel-hydrogen battery, or may be another power storage device such as an electric double layer capacitor. good. In addition, from the viewpoint of effectively improving the acceleration performance of the vehicle, the first secondary battery 10 is a power storage device that has a higher output (that is, has a higher output density) than the second secondary battery 20. is preferred.

The drive motor 50 is capable of outputting power for driving the drive wheels of the vehicle, and is specifically a multiphase AC motor (for example, a three-phase AC motor). The drive motor 50 generates power using power supplied from the first secondary battery 10 via the inverter 40 . Further, the drive motor 50 may have a function (regenerative function) as a generator that generates power using the rotational energy of the drive wheels when the vehicle is decelerating.

Inverter 40 is a power converter capable of bi-directionally converting power between direct current and alternating current, and specifically includes a polyphase bridge circuit. The inverter 40 can convert the DC power supplied from the first secondary battery 10 into AC power and supply it to the driving motor 50 . Further, the inverter 40 can convert AC power regenerated by the drive motor 50 into DC power and supply the DC power to the first secondary battery 10 . A switching element is provided in the inverter 40 , and power supply between the first secondary battery 10 and the drive motor 50 is controlled by controlling the operation of the switching element.

Second secondary battery 20 is a power storage device connected to first secondary battery 10 via DCDC converter 30 . As the second secondary battery 20, for example, a secondary battery such as a lithium ion battery is used. The second secondary battery 20 is not particularly limited to such an example, and may be another secondary battery such as a nickel-metal hydride battery, or may be another power storage device such as an electric double layer capacitor. good. In addition, from the viewpoint of effectively increasing the cruising distance of the vehicle, the second secondary battery 20 is a power storage device with a higher capacity (that is, having a higher energy density) than the first secondary battery 10. is preferred.

The DCDC converter 30 is a voltage converter capable of bi-directional voltage conversion, and includes, for example, a chopper circuit. The DCDC converter 30 can supply the power stored in the first secondary battery 10 to the second secondary battery 20 by appropriately converting the voltage. Further, the DCDC converter 30 can supply the power stored in the second secondary battery 20 to the first secondary battery 10 by appropriately converting the voltage. A switching element is provided in the DCDC converter 30, and the power supply between the first secondary battery 10 side and the second secondary battery 20 side is controlled by controlling the operation of the switching element.

The power receiving unit 60 is connected to the second secondary battery 20 and can receive power transmitted from an external power supply outside the vehicle in which the power supply system 1 is mounted. Specifically, when the vehicle is parked, power is received by the power receiving unit 60, and the first secondary battery 10 and the second secondary battery 20 are charged using the external power supplied from the external power source via the power receiving unit 60. done.

For example, the power receiving unit 60 can receive power transmitted from the external power source while connected to the external power source (ie, in physical contact). Note that the power receiving unit 60 may be provided with a transformer capable of converting voltage. Thereby, the power transmitted from the external power source can be transformed and supplied to the second secondary battery 20 side. Moreover, the power receiving unit 60 may be provided with a power converter capable of converting AC power into DC power. Accordingly, when the external power supply is an AC power supply, the AC power transmitted from the external power supply can be converted into DC power and supplied to the second secondary battery 20 side.

Further, for example, the power receiving unit 60 may be capable of contactlessly receiving power transmitted from an external power supply. In this case, the power receiving unit 60 is specifically provided with a power receiving coil capable of receiving AC power transmitted from an external power source, and a power converter capable of converting the AC power into DC power. As a method of power transmission from the power transmitting coil to the power receiving coil, for example, a magnetic resonance method or an electromagnetic induction method is used.

The first battery sensor 71 detects various state quantities of the first secondary battery 10 and outputs them to the control device 100 . Specifically, the first battery sensor 71 detects the remaining capacity (hereinafter also referred to as first SOC) and temperature of the first secondary battery 10 as state quantities of the first secondary battery 10 .

The second battery sensor 72 detects various state quantities of the second secondary battery 20 and outputs them to the control device 100 . Specifically, the second battery sensor 72 detects the remaining capacity (hereinafter also referred to as the second SOC) and temperature of the second secondary battery 20 as state quantities of the second secondary battery 20 .

Outside air temperature sensor 73 detects the outside air temperature, which is the temperature outside the vehicle, and outputs it to control device 100 .

The control device 100 includes a CPU (Central Processing Unit) that is an arithmetic processing unit, a ROM (Read Only Memory) that is a storage element that stores programs used by the CPU and calculation parameters, and parameters that change as appropriate during execution of the CPU. It is composed of a RAM (Random Access Memory) or the like, which is a storage element for temporary storage.

Also, the control device 100 communicates with each device mounted on the power supply system 1 . Communication between the control device 100 and each device is realized using CAN (Controller Area Network) communication, for example.

Note that the functions of the control device 100 according to the present embodiment may be at least partially divided by a plurality of control devices, and the plurality of functions may be realized by a single control device. When the functions of the control device 100 are at least partially divided by a plurality of control devices, the plurality of control devices may be connected to each other via a communication bus such as CAN.

The control device 100 has, for example, an acquisition unit 110 and a control unit 120 as shown in FIG.

Acquisition unit 110 acquires various types of information used in processing performed by control unit 120 and outputs the acquired information to control unit 120 . For example, the acquisition unit 110 communicates with the first battery sensor 71, the second battery sensor 72, and the outside air temperature sensor 73 to acquire various information output from these sensors.

The control unit 120 controls power supply in the power supply system 1 . For example, control unit 120 includes converter control unit 121 , inverter control unit 122 , and external power control unit 123 .

The converter control unit 121 controls the operation of the DCDC converter 30 (specifically, the operation of the switching element of the DCDC converter 30) to control the switching between the first secondary battery 10 side and the second secondary battery 20 side. control the power supply between Specifically, the converter control unit 121 causes the power stored in the first secondary battery 10 to be supplied to the second secondary battery 20, or supplies the power stored in the second secondary battery 20 to the first secondary battery 20. It can be supplied to the battery 10 . Further, converter control unit 121 can cause external power supplied from an external power supply to second secondary battery 20 through power receiving unit 60 to be supplied to first secondary battery 10 .

The inverter control unit 122 supplies power between the first secondary battery 10 and the drive motor 50 by controlling the operation of the inverter 40 (specifically, the operation of the switching elements of the inverter 40). to control. Specifically, the inverter control unit 122 supplies power stored in the first secondary battery 10 to the drive motor 50, or supplies power regenerated by the drive motor 50 to the first secondary battery 10. can be supplied. Thereby, the inverter control unit 122 can control the power generation and power generation by the drive motor 50 . For example, the inverter control unit 122 controls the output of the drive motor 50 in accordance with the acceleration request, vehicle speed, and other vehicle running conditions.

External power control unit 123 controls external power supplied from an external power supply via power receiving unit 60 . For example, when the power receiving unit 60 is provided with a power converter capable of converting AC power into DC power, the external power control unit 123 controls the operation of the power converter to supply power via the power receiving unit 60. external power can be controlled. Further, for example, the external power control unit 123 controls the external power supplied via the power receiving unit 60 by outputting a command to the external power source to control the power transmitted from the external power source to the power receiving unit 60. You may

As described above, the power supply system 1 includes the power receiving unit 60 connected to the second secondary battery 20 and capable of receiving power transmitted from an external power supply. Thereby, the first secondary battery 10 and the second secondary battery 20 can be charged using the external power supplied from the external power source via the power receiving unit 60 . Here, in the control device 100 of the power supply system 1, in the charging using the external power, the control unit 120 uses the external power to perform the second secondary charging while stopping the supply of power through the DCDC converter 30. When the battery 20 is charged and it is determined that the maximum allowable charging power of the second secondary battery 20 (that is, the amount of power that can be charged per unit time by the second secondary battery 20) is lower than the external power, Power supply from the second secondary battery 20 side to the first secondary battery 10 is started. Thereby, the first secondary battery 10 and the second secondary battery 20 can be charged quickly. The details of the processing related to control of power supply (hereinafter, also referred to as power supply control) performed by the control unit 120 in such charging using external power will be described later.

<2. Operation of control device>
Next, operations of the control device 100 according to the embodiment of the present invention will be described with reference to FIGS. 3 to 8. FIG.

FIG. 3 is a flowchart showing an example of the flow of processing performed by the control unit 120. As shown in FIG. Specifically, the control flow shown in FIG. 3 is started when charging using external power supplied from the external power supply via the power receiving unit 60 is started. In charging using external power, for example, in a state where the power receiving unit 60 can receive power transmitted from the external power supply, an operation by a user such as a driver is received by an input device provided in the vehicle or the external power supply. is started when

When the control flow shown in FIG. 3 is started, first, in step S511, control unit 120 determines whether or not the first SOC is equal to or higher than the reference SOC. If it is determined that the first SOC is greater than or equal to the reference SOC (step S511/YES), the process proceeds to step S513. On the other hand, if it is not determined that the first SOC is greater than or equal to the reference SOC (step S511/NO), the process proceeds to step S517.

The reference SOC is set to a value that can appropriately determine whether or not the current first SOC is high enough to start running the vehicle. It is set to a value of 1 SOC. Note that the reference SOC corresponds to an example of the reference capacity according to the present invention.

If YES in step S511, converter control unit 121 starts power supply from first secondary battery 10 to second secondary battery 20 in step S513.

FIG. 4 is a diagram schematically showing the flow of power in the power supply system 1 when power is being supplied from the first secondary battery 10 to the second secondary battery 20 in charging using external power. is. In FIG. 4 and in FIGS. 5 and 7 to which reference will be made later, the power flow within the power supply system 1 is indicated schematically by arrows.

In charging using external power, when power supply from the first secondary battery 10 to the second secondary battery 20 is started, as shown in FIG. In addition to the external power supplied via the power receiving unit 60 , the battery is charged with the power supplied from the first secondary battery 10 via the DCDC converter 30 . Therefore, the first SOC begins to fall while the second SOC begins to rise.

As will be described later, after power is supplied from the first secondary battery 10 to the second secondary battery 20, a process of stopping power supply via the DCDC converter 30 is performed. In this manner, converter control unit 121 preferably causes first secondary battery 10 to supply power to second secondary battery 20 before stopping power supply via DCDC converter 30 . Thereby, the first SOC can be kept low when the power supply via the DCDC converter 30 is stopped. Therefore, after that, when the maximum allowable charging power of the second secondary battery 20 falls below the external power while the second SOC is increasing, the power is properly transferred from the second secondary battery 20 side to the first secondary battery 10. can be supplied.

Here, from the viewpoint of improving the efficiency of charging using external power, the converter control unit 121 prioritizes the efficiency of the DCDC converter 30 for the power supplied from the first secondary battery 10 to the second secondary battery 20. Power control is preferred. The efficiency characteristics of the DCDC converter 30 with respect to the power supplied between the first secondary battery 10 and the second secondary battery 20 depend on the outside air temperature, the temperature of the DCDC converter 30 itself, or the components near the DCDC converter 30. changes according to the temperature correlated with the temperature of the DCDC converter 30, such as the temperature of . Therefore, the control unit 120, for example, uses the temperature of the outside air temperature sensor 73 to change the power supplied from the first secondary battery 10 to the second secondary battery 20 to the power with priority given to the efficiency of the DCDC converter 30. can be controlled appropriately.

Next, in step S515, control unit 120 determines whether or not the first SOC is below the reference SOC. If it is determined that the first SOC is below the reference SOC (step S515/YES), the process proceeds to step S517. On the other hand, if it is determined that the first SOC is not below the reference SOC (step S515/NO), the process of step S515 is repeated.

In step S515, control unit 120 determines YES when the first SOC actually falls below the reference SOC, and may determine YES when the first SOC is predicted to fall below the reference SOC. good. For example, control unit 120 can predict that the first SOC will fall below the reference SOC based on the history of detected values of the first SOC.

If YES is determined in step S515, converter control unit 121 stops the supply of electric power via DCDC converter 30 in step S517. Thereby, the supply of electric power from the first secondary battery 10 to the second secondary battery 20 ends.

As described above, converter control unit 121 preferably terminates power supply from first secondary battery 10 to second secondary battery 20 when it is determined that the first SOC is lower than the reference SOC. As a result, it is possible to prevent the first SOC from becoming excessively low, so that, for example, even if charging using the external electric power ends halfway, the vehicle can be started to run. The first SOC can be kept high to some extent.

FIG. 5 is a diagram schematically showing the flow of power in power supply system 1 when power supply via DCDC converter 30 is stopped in charging using external power.

In charging using external power, when the supply of power through DCDC converter 30 is stopped, second secondary battery 20 is charged with external power supplied from an external power supply through power receiving unit 60, as shown in FIG. It will be in a state of being charged only by electric power. Therefore, although the speed of increase of the second SOC is lower than before the power supply via the DCDC converter 30 is stopped, the second SOC continues to increase. On the other hand, since charging and discharging of the first secondary battery 10 are stopped, the first SOC is maintained.

Next, in step S519, control unit 120 determines whether or not the maximum allowable charging power of second secondary battery 20 is lower than the external power. If it is determined that the maximum allowable charging power of the second secondary battery 20 is lower than the external power (step S519/YES), the process proceeds to step S521. On the other hand, if it is not determined that the maximum allowable charging power of the second secondary battery 20 is less than the external power (step S519/NO), the process of step S519 is repeated.

As described above, the maximum allowable charging power of the second secondary battery 20 corresponds to the amount of power that can be charged per unit time by the second secondary battery 20, and changes according to the second SOC. Therefore, control unit 120 specifically determines whether or not the maximum allowable charging power of second secondary battery 20 is lower than the external power based on the second SOC.

FIG. 6 is a diagram showing the relationship between the second SOC and the maximum allowable charging power of the second secondary battery 20. As shown in FIG.

As shown in FIG. 6, the maximum allowable charging power of second secondary battery 20 decreases as the second SOC increases. Therefore, when the second SOC is excessively high, the maximum allowable charging power of second secondary battery 20 is lower than the external power supplied from the external power supply via power receiving unit 60 . For example, in FIG. 6, the maximum allowable charging power of the second secondary battery 20 is below the external power when the second SOC is higher than the threshold SOC_th. Therefore, for example, when it is determined that the second SOC has exceeded the threshold SOC_th in the process of increasing, the control unit 120 can determine that the maximum allowable charging power of the second secondary battery 20 is below the external power.

Here, the maximum allowable charging power of the second secondary battery 20 changes according to the temperature of the second secondary battery 20 in addition to the second SOC. Specifically, the maximum allowable charging power of the second secondary battery 20 decreases as the temperature of the second secondary battery 20 decreases. Therefore, from the viewpoint of more appropriately determining whether or not the maximum allowable charging power of the second secondary battery 20 is lower than the external power, the control unit 120 controls whether the maximum allowable charging power of the second secondary battery 20 is lower than the external power. It is preferable to determine whether or not it falls below based on an index value that has a correlation with the temperature of the second secondary battery 20 . In addition to information directly indicating the temperature of the second secondary battery 20 (for example, the detection result of the second battery sensor 72), the index value correlated with the temperature of the second secondary battery 20 includes, for example, Outside temperature or the like may be used.

Note that in step S519, the control unit 120 determines YES when the maximum allowable charging power of the second secondary battery 20 is actually lower than the external power. may be determined to be YES when it is predicted that the power will fall below the external power. For example, the control unit 120 can predict that the maximum allowable charging power of the second secondary battery 20 will fall below the external power based on the history of calculated values of the maximum allowable charging power of the second secondary battery 20. .

If the determination in step S519 is YES, converter control unit 121 starts power supply from second secondary battery 20 to first secondary battery 10 in step S521.

FIG. 7 schematically shows the power flow in the power supply system 1 when power is being supplied from the second secondary battery 20 side to the first secondary battery 10 in charging using external power. It is a diagram.

In charging using external power, when power supply from the second secondary battery 20 side to the first secondary battery 10 is started, as shown in FIG. The supplied external power is distributed and supplied to the first secondary battery 10 and the second secondary battery 20 . Therefore, although the rate of increase in the second SOC is further reduced compared to before power supply from the second secondary battery 20 side to the first secondary battery 10 is started, the second SOC continues to increase. On the other hand, as the first secondary battery 10 starts to be charged with part of the external power supplied from the external power supply via the power receiving unit 60, the first SOC starts to rise.

Specifically, converter control unit 121 controls second secondary battery 20 so that the power supplied to second secondary battery 20 out of the external power is equal to or less than the maximum allowable charging power of second secondary battery 20 . power is supplied to the first secondary battery 10 from the side. As a result, it is possible to appropriately prevent second secondary battery 20 from being damaged due to the supply of power greater than the maximum allowable charging power to second secondary battery 20 .

Here, the magnitude of the power supplied between the first secondary battery 10 and the second secondary battery 20 corresponds to the magnitude of the output of the DCDC converter 30 . Also, the output of the DCDC converter 30 has a maximum output (that is, an upper limit). Therefore, when the external power is larger than the sum of the maximum allowable charging power of the second secondary battery 20 and the maximum output of the DCDC converter 30, the second secondary battery 20 is supplied with power larger than the maximum allowable charging power. Alternatively, a situation may arise in which the power supplied from the second secondary battery 20 side to the first secondary battery 10 exceeds the maximum output of the DCDC converter 30 . These situations cause damage to the second secondary battery 20 or the DCDC converter 30 . Therefore, from the viewpoint of appropriately suppressing damage to each device of the power supply system 1, the external power control unit 123 controls the power supply from the second secondary battery 20 side to the first secondary battery 10 when power is being supplied to the first secondary battery 10. Moreover, it is preferable to control the external power to be equal to or less than the sum of the maximum allowable charging power of the second secondary battery 20 and the maximum output of the DCDC converter 30 .

Next, in step S523, control unit 120 determines whether or not the first SOC and the second SOC have reached the target SOC. If it is determined that the first SOC and the second SOC have reached the target SOC (step S523/YES), the process proceeds to step S525. On the other hand, if it is determined that the first SOC and the second SOC have not reached the target SOC (step S523/NO), the process of step S523 is repeated.

The target SOC of the second SOC is set to, for example, 100% (that is, SOC at full charge). Also, the target SOC of the first SOC is set to, for example, an SOC that is less than 100% (eg, 70%). When the target SOC of the first SOC is set to an SOC smaller than 100%, charging ends when the first SOC becomes an SOC smaller than 100%. A state can be established in which the power regenerated by 50 can be appropriately supplied to the first secondary battery 10 .

If YES is determined in step S523, the external power control unit 123 causes the power receiving unit 60 to terminate power reception from the external power source in step S525. This completes the charging using the external power.

The control flow shown in FIG. 3 then ends.

Here, with reference to FIG. 8, when the power supply control of the present embodiment (that is, the control by the control unit 120) described with reference to the control flow of FIG. Transition of the first SOC and the second SOC will be described.

FIG. 8 is a diagram showing an example of changes in the first SOC and the second SOC during charging using external power when the power supply control of the present embodiment and the power supply control of the reference example are performed. In FIG. 8, transitions of the first SOC and the second SOC when the power supply control of the present embodiment is performed are indicated by solid lines, and transitions of the first SOC and the second SOC when the power supply control of the reference example is performed are shown by solid lines. It is indicated by a two-dot chain line.

In the reference example, unlike the present embodiment, in charging using external power, the first secondary battery is charged from the second secondary battery 20 side regardless of the relationship between the maximum allowable charging power of the second secondary battery 20 and the external power. Power is supplied to the secondary battery 10 . Specifically, in the reference example, the supply of electric power from the second secondary battery 20 side to the first secondary battery 10 is started together with the start of charging using the external power.

In the reference example, for example, as indicated by a two-dot chain line in FIG. Both the first SOC and the second SOC increase as the supply is performed. Here, as described above, when the first secondary battery 10 is a high-output power storage device compared to the second secondary battery 20, the first SOC rises faster than the second SOC, and the time The target SOC (eg, 70%) is reached at T91. After that, only the second secondary battery 20 is charged by the external power, so the second SOC increases while the first SOC is maintained.

Then, at time T92, the second SOC exceeds the threshold SOC_th, so the maximum allowable charging power of the second secondary battery 20 falls below the external power. Therefore, in the reference example, after time T92, the external power is reduced to the maximum allowable charging power of the second secondary battery 20 or less in order to protect the second secondary battery 20 . After time T92, the second SOC increases at a lower rate of increase than before time T92, and reaches the target SOC (eg, 100%) at time T93, thereby completing charging using external power. .

On the other hand, in the present embodiment, for example, as indicated by the solid line in FIG. Power supply from 10 to the second secondary battery 20 is started. As a result, after time T0, the second SOC increases while the first SOC decreases. Then, at time T11, as it is determined that the first SOC falls below the reference SOC, power supply through DCDC converter 30 is stopped, and the first SOC stops decreasing. After time T11, the second SOC rises at a slower speed than before time T11, and exceeds threshold SOC_th at time T12, so the maximum allowable charging power of second secondary battery 20 falls below the external power.

Here, in the present embodiment, at time T12, as it is determined that the maximum allowable charging power of the second secondary battery 20 is lower than the external power, the second secondary battery 20 side to the first secondary battery 10 power supply to the As a result, the external power is distributed and supplied to the first secondary battery 10 and the second secondary battery 20, so charging can be performed without reducing the external power below the maximum allowable charging power of the second secondary battery 20. can continue. Therefore, FIG. 8 shows that after time T12, the rate of increase of the second SOC is lower than before time T12, but the first SOC is increasing. Thereafter, for example, as shown in FIG. 8, after the second SOC reaches the target SOC at time T13, the first SOC reaches the target SOC at time T14, whereby charging using the external power ends. .

As described above, in charging using external power, the control unit 120 according to the present embodiment uses external power to charge the second secondary battery 20 while stopping the supply of power via the DCDC converter 30 and when it is determined that the maximum allowable charging power of the second secondary battery 20 is lower than the external power, the power supply from the second secondary battery 20 side to the first secondary battery 10 is started. . As a result, for example, unlike the reference example described above, the external power is reduced to the maximum allowable charging power of the second secondary battery 20 or less due to the maximum allowable charging power of the second secondary battery 20 falling below the external power. You can suppress the need to arise. Therefore, for example, in the example shown in FIG. 8, the time T14 at which charging ends when the power supply control of the present embodiment is performed is the time T14 at which charging ends when the power supply control of the reference example is performed. The time is before T93. Thus, according to the power supply control of this embodiment, the first secondary battery 10 and the second secondary battery 20 can be charged quickly.

Further, as described above, in charging using external power, the control unit 120 according to the present embodiment controls the power supply from the first secondary battery 10 to the second secondary battery 10 before stopping the power supply via the DCDC converter 30 . Power is preferably supplied to the secondary battery 20 . Thereby, as described above, the first SOC can be brought to a low state when the power supply via the DCDC converter 30 is stopped. For example, in the example shown in FIG. 8, the first SOC is maintained at the reference SOC between time T11 and time T12 when power supply through DCDC converter 30 is stopped. Therefore, when the maximum allowable charging power of the second secondary battery 20 falls below the external power (for example, time T12 in FIG. 8), the power is properly supplied from the second secondary battery 20 side to the first secondary battery 10. can be supplied.

<3. Effect of control device>
Next, effects of the control device 100 according to the embodiment of the present invention will be described.

In the control device 100 according to the present embodiment, the control unit 120 stops the supply of power through the DCDC converter 30 in charging using the external power supplied from the external power supply through the power receiving unit 60. , the external power is used to charge the second secondary battery 20, and when it is determined that the maximum allowable charging power of the second secondary battery 20 is lower than the external power, the first Power supply to the secondary battery 10 is started. As a result, it is possible to prevent the external power from being required to fall below the maximum allowable charging power of the second secondary battery 20 due to the maximum allowable charging power of the second secondary battery 20 falling below the external power. be able to. Therefore, in the power supply system 1 including two or more power storage devices, the first secondary battery 10 and the second secondary battery 20, which are power storage devices, can be quickly charged.

In addition, in the control device 100 according to the present embodiment, in charging using external power, the control unit 120 controls the first Power is preferably supplied from the secondary battery 10 to the second secondary battery 20 . Thereby, the first SOC can be brought to a low state when the power supply via the DCDC converter 30 is stopped. Therefore, when the maximum allowable charging power of the second secondary battery 20 falls below the external power, power can be appropriately supplied from the second secondary battery 20 side to the first secondary battery 10 . Therefore, it is more appropriate to prevent the need to lower the external power to below the maximum allowable charging power of the second secondary battery 20 due to the maximum allowable charging power of the second secondary battery 20 falling below the external power. can be suppressed.

In addition, in the control device 100 according to the present embodiment, the control unit 120 controls the supply of power from the first secondary battery 10 to the second secondary battery 20 in charging using external power so that the first SOC is the reference SOC. is preferably terminated when it is determined that As a result, it is possible to prevent the first SOC from becoming excessively low, so that, for example, even if charging using the external electric power ends halfway, the vehicle can be started to run. The first SOC can be kept high to some extent.

In addition, in the control device 100 according to the present embodiment, the control unit 120 reduces the efficiency of the DCDC converter 30 to the power supplied from the first secondary battery 10 to the second secondary battery 20 in charging using external power. It is preferable to control to prioritized power. Thereby, the efficiency of charging using external power can be improved.

Further, in the control device 100 according to the present embodiment, the control unit 120 controls the charging using the external power when power is being supplied from the second secondary battery 20 side to the first secondary battery 10. Moreover, it is preferable to control the external power to be equal to or less than the sum of the maximum allowable charging power of the second secondary battery 20 and the maximum output of the DCDC converter 30 . As a result, the situation in which power larger than the maximum allowable charging power is supplied to the second secondary battery 20, and the power supplied from the second secondary battery 20 side to the first secondary battery 10 is the maximum output of the DCDC converter 30. It is possible to suppress the occurrence of a situation exceeding Therefore, damage to each device of the power supply system 1 can be appropriately suppressed.

Further, in the control device 100 according to the present embodiment, the control unit 120 determines whether or not the maximum allowable charging power of the second secondary battery 20 is lower than the external power. Preferably, the determination is based on values. Thereby, it is possible to more appropriately determine whether or not the maximum allowable charging power of the second secondary battery 20 is lower than the external power.

<4. Conclusion>
As described above, the power supply system 1 according to the present embodiment includes the power receiving unit 60 connected to the second secondary battery 20 and capable of receiving power transmitted from an external power supply. In the control device 100 of the power supply system 1 as described above, in the charging using the external power, the control unit 120 uses the external power to perform the second secondary charging while stopping the supply of power through the DCDC converter 30 . When the battery 20 is charged and it is determined that the maximum allowable charging power of the second secondary battery 20 is lower than the external power, the power supply from the second secondary battery 20 side to the first secondary battery 10 is stopped. let it start. Accordingly, in the power supply system 1 including two or more power storage devices, the first secondary battery 10 and the second secondary battery 20, which are power storage devices, can be quickly charged.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or applications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

For example, processes described herein using flowcharts do not necessarily have to be performed in the order shown in the flowcharts. Some processing steps may be performed in parallel. Also, additional processing steps may be employed, and some processing steps may be omitted.

1 power supply system 10 first secondary battery 20 second secondary battery 30 DCDC converter 40 inverter 50 drive motor 60 power receiving unit 71 first battery sensor 72 second battery sensor 73 outside air temperature sensor 100 control device 110 acquisition unit 120 control unit 121 converter control unit 122 inverter control unit 123 external power control unit

Claims (6)

a first power storage device connected to the drive motor;
a second power storage device connected to the first power storage device via a voltage converter;
a power receiving unit connected to the second power storage device and capable of receiving power transmitted from an external power supply;
A control device for a power supply system comprising
The control device has a control unit that controls power supply between the first power storage device side and the second power storage device side by controlling the operation of the voltage converter,
The control unit
In charging using external power supplied from the external power supply via the power receiving unit,
charging the second power storage device using the external power while the supply of power via the voltage converter is stopped;
When it is determined that the maximum allowable charging power of the second power storage device is lower than the external power, the supply of power from the second power storage device to the first power storage device is started;
Power system controller. In the charging, the control unit causes the first power storage device to supply power to the second power storage device before stopping power supply via the voltage converter.
The power supply system control device according to claim 1 . In the charging, the control unit terminates the supply of power from the first power storage device to the second power storage device when it is determined that the remaining capacity of the first power storage device is lower than a reference capacity.
3. The power supply system control device according to claim 2. In the charging, the control unit controls the power supplied from the first power storage device to the second power storage device to power that prioritizes the efficiency of the voltage converter.
4. The power system control device according to claim 2 or 3. In the charging, when power is being supplied from the second power storage device to the first power storage device, the control unit divides the external power into the maximum allowable charging power of the second power storage device and the maximum allowable charging power of the second power storage device. Control below the sum of the maximum output of the voltage converter,
A control device for a power supply system according to any one of claims 1 to 4. The control unit determines whether the maximum allowable charging power of the second power storage device is lower than the external power based on an index value correlated with the temperature of the second power storage device.
A control device for a power supply system according to any one of claims 1 to 5.

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