JP5978145B2 - Battery system - Google Patents

Description

  The present invention relates to a storage battery system.

  The storage battery system includes a rechargeable storage battery (secondary battery) such as a lithium ion battery and a control device that controls charging / discharging of the storage battery, and is stored in the storage battery under the control of the control device. This is a system for taking out electric power and storing (charging / discharging) electric power in a storage battery. Such a storage battery system is used as a power source mounted on, for example, an electric vehicle (EV) or a hybrid vehicle (HV).

  Many of the storage batteries provided in the storage battery system have a configuration in which a battery module formed by connecting a plurality of battery cells (unit batteries) in series is connected in series as much as a required voltage is obtained. A storage battery system including such a storage battery includes a voltage monitoring circuit for each battery module constituting the storage battery, and the control device stores the storage battery while referring to monitoring information (monitoring data) of each voltage monitoring circuit. Control of taking out electric power and storing electric power in the storage battery (charge / discharge control) is performed.

  Patent Document 1 below discloses a conventional example of such a storage battery system. Specifically, in Patent Document 1 below, a plurality of lower controllers (cell controllers) that are provided corresponding to each battery module and control the battery cells that constitute the corresponding battery module, and an upper host that controls them. There is disclosed a storage battery system in which a controller (battery controller) is connected by daisy chain serial communication.

Japanese Patent Laid-Open No. 2008-220074

  By the way, the low-order controller provided in the storage battery system of Patent Document 1 described above operates by receiving power supply from the corresponding battery module to perform control of the battery cells and serial communication. For this reason, when an abnormality occurs in the storage battery, a failure occurs in serial communication between the upper controller and the lower controller due to, for example, the stop of power supply from the battery module to the lower controller. An abnormality of the storage battery occurs, for example, when a current path of the storage battery such as a breaker, a fuse, a CID (Current Interrupt Device), a power supply line, or the like provided in the storage battery is cut off (opened).

  In addition, although the power supply from the battery module to the lower controller is normally performed, if an abnormality occurs in the lower controller itself, the operation of the lower controller in which the abnormality occurs stops (or does not operate normally). ). For this reason, a failure occurs in the serial communication between the upper controller and the lower controller, as in the case where an abnormality occurs in the storage battery described above.

  As described above, the main causes of the failure in the serial communication between the upper controller and the lower controller are due to an abnormality of the storage battery and an abnormality of the lower controller. However, in the conventional storage battery system, when a failure occurs in the serial communication with the lower controller, there is a problem that the upper controller cannot determine the cause of the failure.

  This invention is made | formed in view of the said situation, and when a communication failure generate | occur | produces, it aims at providing the storage battery system which can determine the cause of the failure easily.

In order to solve the above-described problems, a storage battery system according to the present invention includes a storage battery having a plurality of battery modules formed by connecting battery cells in series, and the battery cells provided corresponding to the battery modules and forming the battery modules. A plurality of voltage monitoring circuits for individually monitoring the voltage, and a control device for controlling charging / discharging of the storage battery based on monitoring information that is connected to the voltage monitoring circuit in a ring shape and communicates with the voltage monitoring circuit; In the storage battery system, the control device, when a communication failure with the voltage monitoring circuit occurs, the monitoring information of the battery cell obtained from the voltage monitoring circuit before the communication failure occurs The estimated output voltage of the storage battery is calculated using any one of them, and the estimated output voltage is compared with the output voltage of the storage battery after the communication failure has occurred. It is characterized by comprising determination means for determining abnormal portion of.
Further, in the storage battery system of the present invention, when the determination unit has the estimated output voltage larger than the output voltage of the storage battery after the communication failure occurs, the storage battery is the abnormal portion. It is characterized by judging.
Moreover, in the storage battery system of the present invention, when the determination means is that the estimated output voltage is equal to or lower than the output voltage of the storage battery after the occurrence of the communication failure, the voltage monitoring circuit is the abnormal location. It is characterized by judging.
In the storage battery system of the present invention, the determination means multiplies any one of the battery cell monitoring information obtained from the voltage monitoring circuit by the total number of the battery cells provided in the storage battery. In this way, the estimated output voltage is calculated.
Further, in the storage battery system of the present invention, the monitoring information used for calculating the estimated output voltage is a voltage value in the monitoring information of the battery cell obtained from the voltage monitoring circuit before the communication failure occurs. It is characterized by the largest monitoring information.
The storage battery system of the present invention is characterized in that the storage battery includes a plurality of overcurrent interrupting devices provided for each of the battery cells.

  According to the present invention, when a communication failure with the voltage monitoring circuit occurs, the determination means provided in the control device provides battery cell monitoring information obtained from the voltage monitoring circuit before the communication failure occurs. The estimated output voltage of the storage battery is calculated using any one of these, and the estimated output voltage is compared with the output voltage of the storage battery after the occurrence of the communication failure to determine the abnormal location of the communication failure. Therefore, there is an effect that the cause of the communication failure can be easily determined.

It is a block diagram which shows the principal part structure of the storage battery system by one Embodiment of this invention. It is a flowchart which shows the operation | movement at the time of the communication failure generation | occurrence | production of the storage battery system by one Embodiment of this invention. It is a timing chart for demonstrating operation | movement of the storage battery system by one Embodiment of this invention.

  Hereinafter, a storage battery system according to an embodiment of the present invention will be described in detail with reference to the drawings. Hereinafter, in order to facilitate understanding, a storage battery system mounted on an automobile such as an electric vehicle (EV) or a hybrid vehicle (HV) will be described as an example.

  FIG. 1 is a block diagram showing a main configuration of a storage battery system according to an embodiment of the present invention. As shown in FIG. 1, the storage battery system 1 of this embodiment includes a storage battery 10, voltage monitoring circuits 20a to 20d, insulating elements 30a and 30b, and a battery control device 40 (control device). The storage battery system 1 is connected to the inverter INV via the contactors C1 and C2, discharges the electric power stored in the storage battery 10 and supplies it to the inverter INV, and charges the storage battery 10 using regenerative power from the inverter INV. To do.

  Here, the contactors C1 and C2 are a kind of mechanical switch, and the space between the storage battery 10 and the inverter INV is opened or closed. The contactor C1 is provided between the positive terminal of the storage battery 10 and the inverter INV, and the contactor C2 is provided between the negative terminal of the storage battery 10 and the inverter INV. The inverter INV generates power for driving the motor M by driving the motor M with electric power supplied from the storage battery system 1. Further, the inverter INV supplies the electric power generated by the motor M to the storage battery system 1 as regenerative electric power by causing the motor M to function as a generator during deceleration of the automobile.

  The storage battery 10 includes battery modules 11 a to 11 d connected in series, a breaker 12, and a fuse 13, and discharges stored power and charges supplied power under the control of the battery control device 40. . The battery modules 11a to 11d are modules formed by connecting a plurality of battery cells C defined in advance in series. Here, the battery cell C is a unit battery provided in the battery modules 11a to 11d, and is a rechargeable storage battery (secondary battery) such as a lithium ion battery. Each battery cell C is provided with an overcurrent interruption device D for preventing overcurrent. In FIG. 1, the storage battery 10 including four battery modules 11 a to 11 d is illustrated for simplicity of explanation, but the number of battery modules provided in the storage battery 10 is arbitrary.

  The breaker 12 and the fuse 13 are connected in series between the battery module 11b and the battery module 11c, and are provided to cut off (open) the current path of the storage battery 10. For example, the breaker 12 is provided for an operator to manually cut off the current path of the storage battery 10. The fuse 13 is used to automatically cut off the current path of the storage battery 10 when an overcurrent flows through the storage battery 10. The position where the breaker 12 and the fuse 13 are provided is not necessarily between the battery modules 11b and 11c, and may be, for example, between the battery modules 11a and 11b, or between the battery modules 11c and 11d. .

  The voltage monitoring circuits 20a to 20d are provided corresponding to the battery modules 11a to 11d of the storage battery 10, and the voltage of the corresponding battery module (the voltage of the entire corresponding battery module) and each of the corresponding battery modules are provided. The voltage of the battery cell C is monitored. These voltage monitoring circuits 20a to 20d operate by receiving power from the corresponding battery modules 11a to 11d.

  The voltage monitoring circuits 20a to 20d are connected in cascade (daisy chain connection) to each other and connected to the battery control device 40 via the insulating elements 30a and 30b, and communicate with the battery control device 40 to perform the battery module and The monitoring information (monitoring data) of each battery cell C is transmitted to the battery control device 40. In FIG. 1, four voltage monitoring circuits 20 a to 20 d are illustrated for simplicity of explanation, but the same number of voltage monitoring circuits as the battery modules of the storage battery 10 are provided.

  The insulating elements 30a and 30b are elements for electrically insulating the daisy chain-connected voltage monitoring circuits 20a to 20d and the battery control device 40, and are realized by, for example, photocouplers. The insulating element 30a is provided between the battery control device 40 and the voltage monitoring circuit 20a, and the insulating element 30b is provided between the battery control device 40 and the voltage monitoring circuit 20d.

  The battery control device 40 controls charging / discharging of the storage battery 10 based on the monitoring information of the voltage monitoring circuits 20a to 20d. Specifically, the battery control device 40 obtains the remaining capacity (SOC: State Of Charge) of the storage battery 10 from the monitoring information of the voltage monitoring circuits 20a to 20d, and the obtained remaining capacity is within a predetermined allowable range. The charging / discharging of the storage battery 10 is controlled according to the running state of the automobile. For example, when driving the motor M to generate power for running the vehicle, control is performed to discharge the electric power stored in the storage battery 10, and when the vehicle is decelerated, the power is supplied from the inverter INV. Control which charges storage battery 10 with regenerative electric power is performed.

  In addition, when a communication failure occurs between the voltage monitoring circuits 20a to 20d, the battery control device 40 determines the location (abnormal location) that is the cause of the communication failure as an abnormal location determination unit 40a (determination means). Is provided. The abnormal point determination unit 40a may be realized as a hardware circuit. When software that realizes the abnormal point determination unit 40a is read into a computer, the software and hardware resources cooperate with each other. It may be realized.

  When a communication failure with the voltage monitoring circuits 20a to 20d occurs, the abnormal location determination unit 40a is connected to the battery cell C obtained from the voltage monitoring circuits 20a to 20d before (immediately before) the communication failure occurs. An estimated output voltage Vp that is estimated to be the output voltage of the storage battery 10 is calculated using any one of the monitoring information. Then, the abnormal part determination unit 40a compares the calculated estimated output voltage Vp with the output voltage Vo of the storage battery 10 measured by a voltage measurement unit (not shown) provided in the battery control device 40, and determines the abnormal part. judge.

  Specifically, the abnormal part determination unit 40a determines that the storage battery 10 is an abnormal part when the estimated output voltage Vp is larger than the output voltage Vo of the storage battery 10. This is because when the cause of the communication failure is an abnormality of the storage battery 10 (for example, interruption of the breaker 12 or the fuse 13 or interruption of the current path by the overcurrent interruption device C), the output voltage Vo of the storage battery 10 is abnormal. This is because the output voltage Vo (which is substantially the same voltage as the estimated output voltage Vp) before the occurrence of the voltage drops significantly.

  In contrast, when the estimated output voltage Vp is equal to or lower than the output voltage Vo of the storage battery 10, the abnormal point determination unit 40a determines that the voltage monitoring circuits 20a to 20d are abnormal points. This is because when the cause of the communication failure is due to an abnormality in the voltage monitoring circuits 20a to 20d, the output voltage Vo of the storage battery 10 hardly fluctuates, and the output voltage Vo (estimated output voltage before the abnormality occurs). This is because the voltage is maintained at the same level as that of Vp.

Here, the abnormal point determination unit 40a uses the monitoring information having the largest voltage value among the monitoring information of each battery cell C obtained from the voltage monitoring circuits 20a to 20d before (immediately before) a communication failure occurs. Estimated output voltage Vp is calculated. For example, if the voltage (voltage Vm) of one battery cell C constituting the battery module 11a monitored by the voltage monitoring circuit 20a is the largest, the abnormal point determination unit 40a uses the following equation (1) to estimate output The voltage Vp is calculated.
Vp = N · α · Vm (1)

  However, “N” in the above equation (1) is the total number of battery cells C provided in the storage battery 10. The coefficient α is a variation coefficient that is determined in consideration of variations in the voltage value of the battery cell C provided in the storage battery 10. For example, the coefficient α is obtained by previously detecting the maximum voltage and the minimum value of the voltage in the normal state of each battery cell C provided in the storage battery 10 and setting the difference voltage ΔV to determine the design minimum value of the battery cell C. It is obtained by dividing by the difference voltage ΔV. In other words, the abnormal point determination unit 40a is configured such that the battery cell C provided in the storage battery 10 with respect to any one (the largest voltage Vm) of the monitoring information of each battery cell C obtained from the voltage monitoring circuits 20a to 20d. Is multiplied by the variation coefficient (α) to calculate the estimated output voltage Vp.

  Next, operation | movement of the storage battery system 1 in the said structure is demonstrated. FIG. 2 is a flowchart showing an operation when a communication failure occurs in the storage battery system according to the embodiment of the present invention. FIG. 3 is a timing chart for explaining the operation of the storage battery system according to the embodiment of the present invention. Hereinafter, after briefly explaining the operation when the communication failure between the voltage monitoring circuits 20a to 20d and the battery control device 40 does not occur, the operation when the communication failure occurs will be described.

  First, when a communication failure has not occurred, communication is periodically performed between the voltage monitoring circuits 20a to 20d and the battery control device 40, and the monitoring information of the voltage monitoring circuits 20a to 20d is battery control. It is periodically acquired by the device 40 (see “voltage Vc” in FIG. 3). In addition, in the battery control apparatus 40, the output voltage Vo of the storage battery 10 is regularly acquired by the voltage measurement part not shown provided inside separately from the monitoring information of the voltage monitoring circuits 20a-20d (FIG. 3 (see “Output Voltage Vo”).

  When the monitoring information of the voltage monitoring circuits 20a to 20d is acquired, the battery control device 40 obtains the remaining capacity of the storage battery 10, and if the obtained remaining capacity is within a predetermined allowable range, the battery control apparatus 40 responds to the driving state of the vehicle. The charge / discharge of the storage battery 10 is controlled. For example, when driving the motor M to generate power for running the vehicle, control is performed to discharge the electric power stored in the storage battery 10, and when the vehicle is decelerated, the power is supplied from the inverter INV. Control which charges storage battery 10 with regenerative electric power is performed. If no communication failure has occurred, the above operation is repeated.

  Next, when a communication failure occurs, as shown in FIG. 3, the communication error flag, which is a flag indicating that a communication error has occurred, is changed from “L (low)” level to “H” in the battery control device 40. (High) ”level (time t2). Then, the abnormal point determination unit 40a provided in the battery control device 40 uses any one of the monitoring information of each battery cell C obtained from the voltage monitoring circuits 20a to 20d immediately before the communication failure occurs. The estimated output voltage Vp estimated to be the output voltage of the storage battery 10 is calculated (step S11).

  Specifically, the abnormal point determination unit 40a includes the voltage (voltage Vc) of each battery cell C obtained at time t1 immediately before time t2 when the communication error flag changes from “L” level to “H” level. The estimated output voltage Vp is calculated using the one having the largest voltage value. For example, if the voltage (voltage Vm) of one battery cell C constituting the battery module 11a monitored by the voltage monitoring circuit 20a is the largest, the abnormal point determination unit 40a uses the above-described equation (1) to estimate output. The voltage Vp is calculated.

  When the estimated output voltage Vp is calculated, the output voltage Vo of the storage battery 10 is acquired by a voltage measurement unit (not shown) provided inside the battery control device 40 (step S12: time t3). At the same time (or almost simultaneously) when the output voltage Vo is acquired, the abnormality determination flag, which is a flag indicating that abnormality determination is performed, is changed from the “L” level to the “H” level in the battery control device 40. To change. Then, the abnormal part determination unit 40a determines whether or not the estimated output voltage Vp calculated in step S11 is larger than the output voltage Vo acquired in step S12 (step S13).

  When it is determined that the estimated output voltage Vp is greater than the output voltage Vo (when the determination result of step S13 is “YES”), the abnormal point determination unit 40a determines that the storage battery 10 is abnormal ( Step S14). On the other hand, when it is determined that the estimated output voltage Vp is equal to or lower than the output voltage Vo (when the determination result of step S13 is “NO”), the abnormal point determination unit 40a indicates that the voltage monitoring circuits 20a to 20d are abnormal. (Step S15). In this manner, an abnormal location is determined when a communication failure occurs between the voltage monitoring circuits 20a to 20d and the battery control device 40.

  As described above, in the present embodiment, when the communication error flag changes from the “L” level to the “H” level in the battery control device 40, the voltage monitoring circuits 20a to 20d obtain the values before the communication error flag changes. The estimated output voltage Vp of the storage battery 10 is calculated using any one of the monitoring information of each of the battery cells C, and the estimated output voltage Vp and the output voltage Vo of the storage battery 10 are compared to determine an abnormal portion of the communication failure. It is determined by the abnormal part determination unit 40a. For this reason, when a communication failure occurs, it is possible to easily determine the cause of the failure.

  As mentioned above, although the storage battery system by one Embodiment of this invention was demonstrated, this invention is not restrict | limited to embodiment mentioned above, It can change freely within the scope of the present invention. For example, in the above embodiment, in order to facilitate understanding, a storage battery system mounted on a vehicle such as an electric vehicle (EV) or a hybrid vehicle (HV) has been described as an example. However, the present invention is not limited to a vehicle. The present invention can also be applied to a storage battery system provided in a moving body such as a motorcycle or a ship.

DESCRIPTION OF SYMBOLS 1 ... Storage battery system, 10 ... Storage battery, 11a-11d ... Battery module, 20a-20d ... Voltage monitoring circuit, 40 ... Battery control apparatus, 40a ... Abnormal location determination part, C ... Battery cell, D ... Overcurrent interruption device

Claims (6)

A storage battery having a plurality of battery modules formed by connecting battery cells in series, a plurality of voltage monitoring circuits provided corresponding to the battery modules and individually monitoring the voltage of the battery cells forming the battery module, and the voltage In a storage battery system comprising a control device that controls charging / discharging of the storage battery based on monitoring information that is connected to the monitoring circuit in a ring and communicates with the voltage monitoring circuit,
When a communication failure with the voltage monitoring circuit occurs, the control device uses any one of the battery cell monitoring information obtained from the voltage monitoring circuit before the communication failure occurs. And determining means for calculating an estimated output voltage of the storage battery and comparing the estimated output voltage with the output voltage of the storage battery after the occurrence of the communication failure to determine an abnormal location of the communication failure. A storage battery system.   The said determination means determines that the said storage battery is the said abnormal location, when the said estimated output voltage is larger than the output voltage of the said storage battery after the said communication failure generate | occur | produces. Item 10. The storage battery system according to Item 1.   The determination means determines that the voltage monitoring circuit is the abnormal location when the estimated output voltage is equal to or lower than the output voltage of the storage battery after the communication failure has occurred. The storage battery system according to claim 1 or 2.   The determination means calculates the estimated output voltage by multiplying any one of the battery cell monitoring information obtained from the voltage monitoring circuit by the total number of the battery cells provided in the storage battery. The storage battery system according to any one of claims 1 to 3, wherein:   The monitoring information used to calculate the estimated output voltage is monitoring information having the largest voltage value among the monitoring information of the battery cell obtained from the voltage monitoring circuit before the communication failure occurs. The storage battery system according to any one of claims 1 to 4.   The said storage battery is provided with the some overcurrent interruption | blocking apparatus provided with respect to each of the said battery cell, The storage battery system as described in any one of Claims 1-5 characterized by the above-mentioned.

Images