Power supply system, control device, and control program

Abstract

In a power supply system (10), a plurality of storage battery modules (30, 60, 90), provided with storage batteries (31, 61, 91) and conversion circuits (40, 70, 100), and a load (21) are connected in parallel to power supply buses (11, 12). Positive electrodes and negative electrodes of the storage batteries are respectively connected to primary-side terminal pairs (41, 42, 71, 72, 101, 102) of the conversion circuits, and the storage batteries are connected in series to secondary-side terminal pairs (47, 48, 77, 78, 107, 108) of the conversion circuits. By respectively controlling the conversion circuits of the plurality of storage battery modules, the energization operation between the storage batteries and the load, and the temperature-raising operation for raising the temperature of the storage batteries by performing charging / discharging among the storage batteries are simultaneously executed.

Description

Power supply system, control device, and control program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-116077, filed on July 14, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power supply system.

[0003] For example, there is a power supply system in which a plurality of power conversion devices are provided corresponding to a plurality of power storage devices, the number of power storage devices to be operated is set based on the power required by a load device and the allowable charge / discharge power of each power storage device, which is defined based on the state of each of the plurality of power storage devices, and power is exchanged with the load device using the set number of power storage devices (see Patent Document 1).The power supply system described in Patent Document 1 is said to be able to quickly heat up the power storage devices because the charge / discharge current per power storage device is larger and the amount of heat generated per power storage device is larger compared to when power is exchanged with the load device using all of the power storage devices.

[0004] JP 2009-11138 A

[0005] However, in the power supply system described in Patent Document 1, for example, when a set number of power storage devices (storage batteries) are discharged (powered on) to load devices (loads) to raise the temperature of the power storage devices, it is not possible to flexibly adjust the temperature of the power storage devices while discharging to the load devices.Furthermore, when a set number of power storage devices are charged (powered on) from the load devices to raise the temperature of the power storage devices, it is not possible to flexibly adjust the temperature of the power storage devices while charging from the load devices.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its main purpose is to enable a power supply system having multiple storage batteries to flexibly adjust the temperature of the storage batteries while power is supplied between the storage batteries and a load.

[0007] A first means for solving the above problem is a power supply system in which a load and a plurality of storage battery modules each including a storage battery and a conversion circuit that converts power input from the storage battery to a primary side terminal pair and outputs the power from a secondary side terminal pair are connected in parallel to a power supply bus, wherein the positive and negative electrodes of the storage batteries are respectively connected to the primary side terminal pair of the conversion circuit and the storage batteries are connected in series to the secondary side terminal pair of the conversion circuit, and the system comprises: a current supply execution unit that controls each of the conversion circuits of the plurality of storage battery modules to perform a current supply operation between the storage batteries and the load; and a temperature rise execution unit that controls each of the conversion circuits of the plurality of storage battery modules to perform a temperature rise operation to raise the temperature of the plurality of storage batteries by charging and discharging between the plurality of storage batteries, and the current supply operation by the current supply execution unit and the temperature rise operation by the temperature rise execution unit are performed simultaneously.

[0008] According to the above configuration, in the power supply system, a plurality of storage battery modules each including a storage battery and a conversion circuit that converts power input from the storage battery to a pair of primary terminals and outputs the converted power from a pair of secondary terminals, and a load are connected in parallel to a power supply bus. This allows the plurality of storage batteries to discharge power to the load via the power supply bus, and allows the load to charge the storage batteries via the power supply bus. Note that the power supply bus is a power path (common power path) shared in the power supply system to connect a plurality of circuits, devices, and equipment to exchange power.

[0009] The positive and negative electrodes of the storage battery are connected to the primary terminal pair of the conversion circuit, respectively, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit. With this configuration, the output voltage Vm of the storage battery module is the sum of the output voltage Vb of the storage battery and the output voltage Vo of the conversion circuit. Therefore, compared to a storage battery module in which the storage battery is connected in parallel to the secondary terminal pair of the conversion circuit, the output voltage Vo required of the conversion circuit when the output voltage Vm of the storage battery module is required can be reduced. Therefore, the rated voltage of the conversion circuit can be lowered, and the rated capacity of the conversion circuit can be reduced, thereby enabling the conversion circuit to be made more compact.

[0010] Here, the energization execution unit controls the conversion circuits of the plurality of storage battery modules to perform energization between the storage battery and the load. This allows the temperature of the storage battery that has performed the energization with the load to be increased. Furthermore, the temperature-raising execution unit controls the conversion circuits of the plurality of storage battery modules to perform a temperature-raising operation, which increases the temperature of the plurality of storage batteries by charging and discharging between the plurality of storage batteries. This allows the temperature of the plurality of storage batteries that have performed the temperature-raising operation to be increased separately from the temperature-raising of the storage batteries caused by the energization between the storage battery and the load. Furthermore, the power supply system simultaneously performs the energization operation by the energization execution unit and the temperature-raising operation by the temperature-raising execution unit. This allows the temperature of the storage battery to be flexibly adjusted while energizing the storage battery and the load.

[0011] In the second aspect, a status acquisition unit is provided that acquires the status of the plurality of storage batteries, and the energization execution unit adjusts the power ratio of the plurality of storage batteries in the energization operation based on the status of the plurality of storage batteries acquired by the status acquisition unit. With this configuration, the power ratio of the plurality of storage batteries in the energization operation is adjusted based on the status of the plurality of storage batteries, so that the temperature of the storage batteries can be more flexibly adjusted through the energization operation by the energization execution unit.

[0012] In a third aspect, the status acquisition unit acquires the state of charge of the plurality of storage batteries as the state of the plurality of storage batteries, and the energization execution unit adjusts the power ratio of the plurality of storage batteries in the energization operation so as to reduce the difference in the state of charge of the plurality of storage batteries acquired by the status acquisition unit. With this configuration, the energization operation by the energization execution unit not only allows current to be applied between the storage batteries and the load, but also reduces the difference in the state of charge of the plurality of storage batteries.

[0013] In a fourth aspect, the status acquisition unit acquires the health statuses of the plurality of storage batteries as the statuses of the plurality of storage batteries, and the energization execution unit increases the power ratio in the energization operation for a storage battery with a higher health status acquired by the status acquisition unit. With this configuration, the energization operation by the energization execution unit not only energizes the storage battery and the load, but also reduces the difference in health status among the plurality of storage batteries. In other words, by increasing the energization power in the energization operation for a storage battery with a higher health status, the difference in health status between the storage batteries and the other storage batteries can be reduced. The state of health (SOH) [%] of a storage battery can be calculated using the formula: SOH [%] = current full charge capacity × 100 / full charge capacity at time of manufacture.

[0014] In a fifth aspect, a status acquisition unit is provided that acquires at least one of the status, physical location, and power supply schedule of the plurality of storage batteries, and the temperature increase execution unit determines the storage batteries to be subjected to the temperature increase operation based on the status of the plurality of storage batteries acquired by the status acquisition unit. With this configuration, it is possible to appropriately determine the storage batteries to be subjected to the temperature increase operation based on the status of the plurality of storage batteries. Note that acquiring the power supply schedule includes receiving the power supply schedule via communication or the like and predicting the power supply schedule.

[0015] In a sixth aspect, the status acquisition unit acquires the health statuses of the plurality of storage batteries as the statuses of the plurality of storage batteries, and the temperature increase execution unit determines the storage battery whose health status acquired by the status acquisition unit is higher than that of the other storage batteries as the execution target. With this configuration, the temperature increase execution unit not only increases the temperatures of the plurality of storage batteries but also reduces the difference in health status among the plurality of storage batteries. In other words, by actively executing the temperature increase operation on a storage battery whose health status is higher than that of the other storage batteries, the difference in health status between the storage batteries and the other storage batteries can be reduced.

[0016] In the seventh means, the status acquisition unit acquires the physical arrangement of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines, based on the physical arrangement of the multiple storage batteries acquired by the status acquisition unit, as the execution target a storage battery that is less likely to receive heat from the outside than other storage batteries, or a storage battery that is more likely to radiate heat to the outside than other storage batteries.

[0017] According to the above configuration, the temperature-raising execution unit determines the storage battery that receives less heat from the outside than the other storage batteries as the execution target. Therefore, it is possible to preheat the storage battery that heats up less than the other storage batteries or that cools down more easily than the other batteries. Alternatively, the temperature-raising execution unit determines the storage battery that dissipates heat to the outside more easily than the other storage batteries as the execution target. Therefore, it is possible to preheat the storage battery that cools down more easily than the other storage batteries.

[0018] In an eighth aspect, when the outside air temperature is lower than the temperatures of the plurality of storage batteries, the temperature-raising execution unit executes the temperature-raising operation to maintain the temperature of the storage battery determined to be the execution target at or above a specified temperature. With this configuration, for example, even if the outside air temperature is lower than the temperatures of the plurality of storage batteries after the end of the current-carrying operation between the storage battery and the load, the temperature of the storage battery can be maintained at or above a specified temperature by the temperature-raising operation. Therefore, when a charge / discharge request is made to the power supply system, charge / discharge in accordance with the charge / discharge request can be quickly executed.

[0019] In a ninth aspect, the status acquisition unit acquires the states and the energization schedule of the plurality of storage batteries as the statuses of the plurality of storage batteries, and the heating execution unit determines the storage batteries to be subjected to the heating operation based on the states and the energization schedule of the plurality of storage batteries acquired by the status acquisition unit. With this configuration, the storage batteries to be subjected to the heating operation can be appropriately determined in consideration of the states and the energization schedule of the plurality of storage batteries. For example, by determining the storage batteries to be subjected to the heating operation that are scheduled to be subjected to the energization operation with a load and require heating as the storage batteries to be subjected to the heating operation, the operation of energizing the load can be started promptly.

[0020] In a tenth aspect, the temperature rise execution unit determines, as the target battery, a battery that has a larger increase in the available power before and after the temperature rise operation than other batteries. With this configuration, the available power of the battery can be effectively increased by the temperature rise operation, and the current carrying capacity of the power supply system can be effectively improved.

[0021] In an eleventh aspect, the temperature rise execution unit sets the charging rate of the storage battery determined to be the execution target higher than the charging rates of the other storage batteries by charging the storage battery from the load or the other storage batteries before executing the temperature rise operation. With this configuration, even if the charging rate of the storage battery to be executed decreases due to the temperature rise operation, it is possible to prevent the difference in charging rates of the multiple storage batteries from becoming large.

[0022] The twelfth means is a control device applied to a power supply system in which a plurality of storage battery modules each including a storage battery and a conversion circuit that converts power input from the storage battery to a primary side terminal pair and outputs the power from a secondary side terminal pair, and a load are connected in parallel to a power supply bus, the positive and negative electrodes of the storage batteries are respectively connected to the primary side terminal pair of the conversion circuit, and the storage batteries are connected in series to the secondary side terminal pair of the conversion circuit, the control device comprising: a current supply execution unit that controls each of the conversion circuits of the plurality of storage battery modules to perform a current supply operation between the storage batteries and the load; and a temperature rise execution unit that controls each of the conversion circuits of the plurality of storage battery modules to perform a temperature rise operation to raise the temperature of the plurality of storage batteries by charging and discharging between the plurality of storage batteries, and the current supply operation by the current supply execution unit and the temperature rise operation by the temperature rise execution unit are performed simultaneously.

[0023] According to the above configuration, the control device applied to the power supply system can achieve the same effects as the first means.

[0024] The thirteenth means is a control program applied to a power supply system in which a plurality of storage battery modules each including a storage battery and a conversion circuit that converts power input from the storage battery to a primary terminal pair and outputs the power from a secondary terminal pair, and a load are connected in parallel to a power supply bus, the positive and negative electrodes of the storage batteries are respectively connected to the primary terminal pair of the conversion circuit, and the storage batteries are connected in series to the secondary terminal pair of the conversion circuit, the control program causing a computer to simultaneously execute a process of controlling the conversion circuits of the plurality of storage battery modules to perform a current flow operation between the storage batteries and the load, and a process of controlling the conversion circuits of the plurality of storage battery modules to perform a temperature raising operation to raise the temperature of the plurality of storage batteries by charging and discharging between the plurality of storage batteries.

[0025] According to the above configuration, by causing a computer to execute a control program applied to the power supply system, it is possible to achieve the same effects as those of the first means.

[0026] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a circuit diagram of a power supply system, Fig. 2 is a circuit diagram showing an example of a conversion circuit, Fig. 3 is a flowchart showing the procedure of a current supply operation and a temperature rise operation, Fig. 4 is a graph showing the relationship between the internal resistance of a storage battery and the AC current frequency, Fig. 5 is a graph showing the relationship between the amount of heat generated and the current amplitude, Fig. 6 is a schematic diagram showing an example of the current supply operation and the temperature rise operation, Fig. 7 is a time chart showing the current of the storage battery in each storage battery module, Fig. 8 is a time chart showing the transitions of the operating state, the storage battery temperature, and the storage battery SOC of each storage battery module, and Fig. 9 is a time chart showing the transitions of the operating state, the storage battery temperature, and the storage battery SOC of each storage battery module in a comparative example. 10 is a schematic diagram showing another example of the execution of the current supply operation and the temperature rise operation, FIG. 11 is a schematic diagram showing another example of the execution of the current supply operation and the temperature rise operation, FIG. 12 is a schematic diagram showing another example of the execution of the current supply operation and the temperature rise operation, FIG. 13 is a schematic diagram showing another example of the execution of the current supply operation and the temperature rise operation, FIG. 14 is a schematic diagram showing another example of the execution of the current supply operation and the temperature rise operation, FIG. 15 is a schematic diagram showing an example of the execution of the temperature rise operation, FIG. 16 is a schematic diagram showing another example of the execution of the temperature rise operation, FIG. 17 is a circuit diagram of a modified example of the power supply system, FIG. 18 is a circuit diagram of a modified example of the conversion circuit, FIG. 19 is a circuit diagram of another modified example of the conversion circuit, and FIG. 20 is a circuit diagram of a modified example of the storage battery module.

[0027] Hereinafter, an embodiment of a power supply system that inputs and outputs power to and from a load will be described with reference to the drawings.

[0028] 1 , the power supply system 10 includes buses 11 and 12 (power supply buses), a first storage battery module 30, a second storage battery module 60, a third storage battery module 90, a voltage sensor 13, a current sensor 19, an ECU (Electronic Control Unit) 16, etc. The positive side (positive side) of the bus is referred to as bus 11, and the negative side (negative side) of the bus is referred to as bus 12. The bus 12 is grounded.

[0029] A first storage battery module 30 (storage battery module), a second storage battery module 60 (storage battery module), a third storage battery module 90 (storage battery module), a load 21, and a voltage sensor 13 are connected in parallel to the buses 11 and 12. The storage battery modules 30, 60, and 90 input and output power to and from the buses 11 and 12. The load 21 includes multiple loads and inputs and outputs power to and from the buses 11 and 12. The voltage sensor 13 detects a bus voltage Vbus, which is the voltage between the buses 11 and 12. The current sensor 19 detects a current flowing through the bus 12 (load 21).

[0030] The load 21 may be, for example, a combination of an inverter and a motor generator (MG) (inverter-equipped motor unit), an electric heater, a DC-DC converter, an external charger (charging device), or the like. The motor generator (MG) drives, for example, an electric vehicle using power supplied from the inverter, or generates electricity regeneratively using rotational force imparted by the electric vehicle. The inverter converts power between the buses 11 and 12 and the MG. The electric heater generates heat using high voltage (voltage) supplied from, for example, the buses 11 and 12 to warm the interior of the vehicle, the battery, etc. The DC-DC converter converts DC power supplied from the buses 11 and 12 to supply DC power, or converts DC power supplied from a solar panel or the like to supply DC power to the buses 11 and 12. The external charger inputs power to the buses 11 and 12 to charge the storage batteries 31, 61, and 91.

[0031] The first storage battery module 30 includes a first storage battery 31, a first current sensor 33, a first drive circuit 35, a first conversion circuit 40, relays 40a and 40b, a BMU (Battery Management Unit) 32, and the like. The first storage battery 31 (storage battery) is a high-voltage secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery, and may be of any type. The first current sensor 33 (current sensor) detects the current flowing through the first storage battery 31. The value detected by the first current sensor 33 is input to the ECU 16 and used, for example, to calculate the state of charge (SOC) [%] of the first storage battery 31. The first drive circuit 35 (drive circuit) drives switching elements (described below) included in the first conversion circuit 40 to turn on and off. The first drive circuit 35 is controlled by the ECU 16. The relays 40a and 40b connect and disconnect the storage battery module 30 to and from the buses 11 and 12, respectively. The first storage battery 31 (storage battery) may be a secondary battery that is not a high voltage battery. A detection value by the first current sensor 33 may be input to the BMU 32.

[0032] The first conversion circuit 40 (conversion circuit) includes a primary-side terminal pair, that is, a primary-side positive terminal 41 and a negative terminal 42, and a secondary-side terminal pair, that is, a secondary-side positive terminal 47 and a negative terminal 48. The negative terminal of the first storage battery 31 is connected to the bus 12. The primary-side positive terminal 41 is connected to the positive terminal of the first storage battery 31, and the primary-side negative terminal 42 is connected to the negative terminal of the first storage battery 31. The secondary-side negative terminal 48 is also connected to the positive terminal of the first storage battery 31. The secondary-side positive terminal 47 is connected to the bus 11. That is, the positive and negative terminals of the first storage battery 31 are connected to the primary-side terminal pair 41, 42 of the first conversion circuit 40, respectively, and the first storage battery 31 is connected in series to the secondary-side terminal pair 47, 48 of the first conversion circuit 40. The first conversion circuit 40 converts the power input from the first storage battery 31 to the primary-side terminal pair 41, 42 and outputs it from the secondary-side terminal pair 47, 48. The first conversion circuit 40 is a bidirectional conversion circuit that can also convert the power input to the secondary-side terminal pair 47, 48 and output it from the primary-side terminal pair 41, 42.

[0033] The BMU 32 (status acquisition unit) includes a temperature sensor, a storage device, a computing device, and the like. The temperature sensor detects the temperature (status) of the first storage battery 31. The storage device (storage unit) stores characteristics of the first storage battery 31. The characteristics of the first storage battery 31 include, for example, the relationship between the internal resistance of the first storage battery 31 and the AC current frequency (see FIG. 4 ), the relationship between the amount of heat generated by the first storage battery 31, the current amplitude, and the current flow constraint (see FIG. 5 ), and the relationship between the open circuit voltage (OCV) of the first storage battery 31 and the SOC. The BMU 32 calculates (acquires) the SOC (status) of the first storage battery 31 by applying the open circuit voltage OCV detected by the voltage sensor 51 to a graph or map that defines the relationship between the open circuit voltage OCV and the SOC. The BMU 32 updates the SOC calculated based on the open circuit voltage OCV based on the integrated value of the current detected by the first current sensor 33. The BMU 32 estimates (acquires) the SOH (State Of Health) of the first storage battery 31 as follows. For example, the BMU 32 calculates (acquires) the full charge capacity (state) of the first storage battery 31 using the formula: Full charge capacity [Ah] = Charge amount × 100 / (SOC after charge - SOC before charge). The charge amount is the integrated value of the current from the start to the end of charging, and can be calculated by, for example, integrating the current detected by the current sensor 33. For example, the BMU 32 calculates (acquires) the SOH [%] (state) of the first storage battery 31 using the formula: SOH [%] = Current full charge capacity × 100 / Full charge capacity at the time of manufacture. In addition, the calculation (acquisition) of the SOC and SOH of the first storage battery 31 may be performed by the status acquisition unit 16e (ECU 16), or the status acquisition unit 16e (ECU 16) may receive (acquire) the SOC and SOH of the first storage battery 31 from the BMU 32.

[0034] The second storage battery module 60 has a configuration similar to that of the first storage battery module 30 and includes a second storage battery 61 (storage battery), a second current sensor 63 (current sensor), a second drive circuit 65 (drive circuit), a second conversion circuit 70, relays 70a and 70b, a BMU 62, and the like. The second conversion circuit 70 (conversion circuit) has a configuration similar to that of the first conversion circuit 40 and includes a primary-side terminal pair consisting of a primary-side positive terminal 71 and a negative terminal 72, and a secondary-side terminal pair consisting of a secondary-side positive terminal 77 and a negative terminal 78. The connection configuration of these components is also similar to that of the first storage battery module 30, and therefore the above description of the first storage battery module 30 is also applicable. The BMU 62 (status acquisition unit) has a configuration similar to that of the BMU 32, and therefore the above description of the BMU 32 is also applicable. Although the first storage battery module 30 and the second storage battery module 60 have components with similar functions, the ratings and withstand voltages of the respective components may differ from each other.

[0035] The third storage battery module 90 has a configuration similar to that of the first storage battery module 30 and includes a third storage battery 91 (storage battery), a third current sensor 93 (current sensor), a third drive circuit 95 (drive circuit), a third conversion circuit 100, relays 100a and 100b, a BMU 92, etc. The third conversion circuit 100 (conversion circuit) has a configuration similar to that of the first conversion circuit 40 and includes a primary-side terminal pair consisting of a primary-side positive terminal 101 and a negative terminal 102, and a secondary-side terminal pair consisting of a secondary-side positive terminal 107 and a negative terminal 108. The connection configuration of these components is also similar to that of the first storage battery module 30, and therefore the above description of the first storage battery module 30 is applicable. The BMU 92 (status acquisition unit) has a configuration similar to that of the BMU 32, and therefore the above description of the BMU 32 is applicable. Although the first storage battery module 30 and the third storage battery module 90 have configurations with similar functions, the ratings and withstand voltages of the respective configurations may be different from each other.

[0036] FIG. 2 shows an example of a first conversion circuit 40. The first conversion circuit 40 is a well-known center-tap isolated DC-DC converter. The first conversion circuit 40 includes switching elements 43 to 46, 54, and 55, smoothing capacitors 50 and 57, a transformer 53, a reactor 56, voltage sensors 51 and 59, and current sensors 52 and 58. The switching elements 43 to 46, 54, and 55 are, for example, MOSFETs or IGBTs (insulated gate bipolar transistors). The switching elements 43 to 46 form a full-bridge circuit. The connection point between the switching element 43 and the switching element 44 and the connection point between the switching element 45 and the switching element 46 are connected to both ends of the primary coil of the transformer 53, respectively. The switching elements 54 and 55 are connected between both ends of the secondary coil of the transformer 53 and the reactor 56, respectively. The voltage sensor 51 detects the voltage between the negative terminal 42 and the positive terminal 41 on the primary side, i.e., the output voltage Vb of the first storage battery 31. The current sensor 52 detects the input current Ii, which is the current input to the primary side circuit. The voltage sensor 59 detects the voltage between the negative terminal 48 and the positive terminal 47 on the secondary side, i.e., the output voltage Vo of the first conversion circuit 40. The current sensor 58 detects the current flowing through the reactor 56, i.e., the output current Io of the first conversion circuit 40. The detected values ​​of the voltage sensors 51, 59 and the current sensors 52, 58 are input to the ECU 16. The detected value of the voltage sensor 51 may also be input to the BMU 32.

[0037] The ECU 16 (control device) is configured as a microcomputer (computer) including, for example, a CPU, ROM, RAM, a storage device, an input / output interface, etc. The ECU 16 controls the states of the relays 40a, 40b, 70a, 70b, 100a, 100b and the state of the load 21. Furthermore, the ECU 16 executes a control program applied to the power supply system 10 to realize functions such as a bus voltage setting unit 16a, a control unit 16b, a current application execution unit 16c, a temperature increase execution unit 16d, and a status acquisition unit 16e. The BMUs 32, 62, 92 and the ECU 16 can communicate with each other via wire or wirelessly.

[0038] The bus voltage setting unit 16a sets a bus voltage request value Vbus*, which is a voltage that is requested to be supplied from the buses 11 and 12 to the load 21. The bus voltage setting unit 16a sets the bus voltage request value Vbus* based on the state of the load 21.

[0039] The control unit 16b controls the output voltages Vo1, Vo2, and Vo3 of the conversion circuits 40, 70, and 100 so that the output voltages Vm1, Vm2, and Vm3 of the storage battery modules 30, 60, and 90 respectively become the requested bus voltage value Vbus* (approach the requested bus voltage value Vbus*). For example, the control unit 16b controls the switching elements 43-46, 54, and 55 based on the detected values ​​of the voltage sensors 51 and 59 and the current sensors 52 and 58, thereby controlling the first output voltage Vo1 of the first conversion circuit 40 to become the requested first output voltage value Vo1* (approach the requested first output voltage value Vo1*). More specifically, the control unit 16b sets the requested first output voltage value Vo1* to a voltage obtained by subtracting the first output voltage Vb1 of the first storage battery 31 from the requested bus voltage value Vbus* (Vo1*=Vbus*−Vb1). Similarly, the control unit 16b controls the second output voltage Vo2 of the second conversion circuit 70 to become the second output voltage request value Vo2* (approach the second output voltage request value Vo2*). Specifically, the second output voltage request value Vo2* is set to a voltage obtained by subtracting the second output voltage Vb2 of the second storage battery 61 from the bus voltage request value Vbus* (Vo2* = Vbus* - Vb2). Similarly, the control unit 16b controls the third output voltage Vo3 of the third conversion circuit 100 to become the third output voltage request value Vo3* (approach the third output voltage request value Vo3*). Specifically, the third output voltage request value Vo3* is set to a voltage obtained by subtracting the third output voltage Vb3 of the third storage battery 91 from the bus voltage request value Vbus* (Vo3* = Vbus* - Vb3).

[0040] The energization execution unit 16c controls the conversion circuits 40, 70, 100 of the storage battery modules 30, 60, 90, respectively, to execute an energization operation between the storage batteries 31, 61, 91 and the load 21. The energization operation includes a discharge operation from the storage batteries 31, 61, 91 to the load 21 (e.g., a motor unit with an inverter) and a charge operation from the load 21 (e.g., an external charger) to the storage batteries 31, 61, 91. In the energization operation, the energization execution unit 16c passes a DC load current between the storage batteries 31, 61, 91 and the load 21.

[0041] The temperature rise execution unit 16d controls the conversion circuits 40, 70, and 100 of the storage battery modules 30, 60, and 90, respectively, to perform a temperature rise operation that charges and discharges the storage batteries 31, 61, and 91 to raise the temperatures of the storage batteries 31, 61, and 91. The temperature rise execution unit 16d flows an AC heat-creating current between the storage batteries 31, 61, and 91 during the temperature rise operation.

[0042] The status acquisition unit 16e acquires the status of the storage batteries 31, 61, 91. The status of the storage batteries 31, 61, 91 includes, for example, the above-mentioned states of the storage batteries 31, 61, 91 acquired by the BMUs 32, 62, 92. The status of the storage batteries 31, 61, 91 includes, for example, the physical arrangement of the storage batteries 31, 61, 91. The physical arrangement includes the location of the storage batteries 31, 61, 91 in the vehicle, the positional relationship between the storage batteries 31, 61, 91 and other devices, and the like, and is stored, for example, in a storage device of the ECU 16. The status of the storage batteries 31, 61, 91 includes, for example, a power supply schedule for the storage batteries 31, 61, 91. The power supply schedule is, for example, the next charging timing or the next discharging timing for the storage batteries 31, 61, 91, and can be received (acquired) from the ECU or predicted (acquired) from the vehicle status.

[0043] 3 is a flowchart showing the procedure of the current supply operation and the temperature increase operation. This series of processes is repeatedly executed at a predetermined cycle by the ECU 16. Note that the current supply operation includes the discharge operation and the charge operation of the storage batteries 31, 61, 91, but the discharge operation will be mainly described here as an example.

[0044] First, the status of each storage battery 31, 61, 91 is acquired (S10). The status of each storage battery 31, 61, 91 includes the temperature of each storage battery 31, 61, 91, the characteristics, SOC [%], SOH [%], the physical location, the power supply schedule, etc. Based on the acquired temperature of each storage battery 31, 61, 91, it is determined whether the temperature variation of the storage batteries 31, 61, 91 is equal to or less than a predetermined value (S11). For example, it is determined whether the difference between the temperature of the hottest storage battery and the temperature of the coldest storage battery among the storage batteries 31, 61, 91 is equal to or less than a predetermined value. The power upper limit (allowable power) as a power supply constraint for the storage batteries 31, 61, 91 decreases as the temperature of the storage batteries decreases. Therefore, the predetermined value is set to, for example, a value that can determine whether the difference in allowable power of the storage batteries becomes undesirable. If it is determined that the temperature variation of the storage batteries 31, 61, 91 is equal to or less than the predetermined value (S11: YES), the system transitions to a no-heat-generation mode (S12). The no-heat-generation mode is a mode in which the above-described current-carrying operation is performed but the above-described temperature-raising operation is not performed.

[0045] Next, based on the acquired SOC [%] of each storage battery 31, 61, 91, it is determined whether the SOC variation among the storage batteries 31, 61, 91 is equal to or less than a predetermined value (S13). For example, it is determined whether the difference between the SOC [%] of the storage battery 31, 61, 91 with the highest SOC [%] and the SOC [%] of the storage battery 31, 61, 91 with the lowest SOC [%] is equal to or less than a predetermined value. If the voltage difference between the output voltages Vb of the storage batteries 31, 61, 91 becomes too large, it becomes difficult for the conversion circuits 40, 70, 100 to adjust the output voltages Vm of the storage battery modules 30, 60, 90 to match each other. Therefore, the predetermined value is set to, for example, a value that allows determination that the voltage difference between the output voltages Vb of the storage batteries 31, 61, 91 is too large. If it is determined that the SOC variation among the storage batteries 31, 61, 91 is equal to or less than the predetermined value (S13: YES), the process proceeds to S14.

[0046] In the process of S14, based on the acquired SOH [%] of each storage battery 31, 61, 91, it is determined whether the SOH variation among the storage batteries 31, 61, 91 is equal to or less than a predetermined value. For example, it is determined whether the difference between the SOH [%] of the storage battery 31, 61, 91 with the highest SOH [%] and the SOH [%] of the storage battery 31, 61, 91 with the lowest SOH [%] is equal to or less than a predetermined value. The SOH [%] of the storage batteries 31, 61, 91 correlates with the degree of deterioration of the storage batteries 31, 61, 91 and, ultimately, the lifespan of the storage batteries 31, 61, 91. Therefore, the predetermined value is set to, for example, a value that can determine whether the difference in the degree of deterioration among the storage batteries 31, 61, 91 becomes undesirable. If it is determined that the SOH variation among the storage batteries 31, 61, 91 is equal to or less than the predetermined value (S14: YES), the process proceeds to S15.

[0047] In the process of S15, the equal distribution value obtained by equally distributing the load current (discharge current or charge current) required for the load 21 is issued to each storage battery module 30, 60, 90 as a current command value. At this time, if each current command value exceeds the DC Win / Wout constraint shown in FIG. 5 , each current command value is corrected to fall within the DC Win / Wout constraint. For example, the DC power upper limit value as the DC Win / Wout constraint during discharge of the storage battery 31, 61, 91 increases as the temperature increases up to the upper limit of the appropriate temperature range of the storage battery 31, 61, 91. Furthermore, as the SOC [%] of the storage battery 31, 61, 91 increases, the upper limit value of DC Win decreases and the upper limit value of DC Wout increases. Then, the conversion circuits 40, 70, 100 of each storage battery module 30, 60, 90 are controlled so that the currents flowing between the storage battery module 30, 60, 90 and the load 21 become equal to the current command values. Thereafter, this series of processes is temporarily ended (END).

[0048] On the other hand, if it is determined that the SOC variation of the storage batteries 31, 61, 91 is not below the predetermined value (S13: NO), and if it is determined that the SOH variation of the storage batteries 31, 61, 91 is not below the predetermined value (S14: NO), the process proceeds to S16.

[0049] In the process of S16, an unequal distribution value, which unevenly distributes the load current (discharge current or charge current) required for the load 21, is issued to each storage battery module 30, 60, 90 as a current command value. Specifically, if the SOC variation among the storage batteries 31, 61, 91 is not equal to or less than a predetermined value (NO in S13), the unequal distribution value is set so as to reduce the difference in SOC [%]. For example, when discharging from the storage batteries 31, 61, 91 to the load, the unequal distribution value is increased for storage batteries with higher SOC [%]. When charging from the load to the storage batteries 31, 61, 91, the unequal distribution value is increased for storage batteries with lower SOC [%]. In other words, based on the acquired SOC [%] of each storage battery 31, 61, 91, the power ratio of the storage batteries 31, 61, 91 during the energization operation is adjusted so as to reduce the difference in SOC [%] among the storage batteries 31, 61, 91. Furthermore, if the SOH variation among the storage batteries 31, 61, and 91 is not equal to or less than the predetermined value (NO in S14), the unequal distribution value is increased for the storage battery with a higher SOH [%]. That is, based on the acquired SOH [%] of each storage battery 31, 61, and 91, the power ratio of the storage battery during current conduction (discharging and charging) is increased for the storage battery with a higher SOH [%]. If each current command value exceeds the DC Win / Wout constraint shown in FIG. 5 , the current command value is corrected to fall within the DC Win / Wout constraint. Then, the conversion circuits 40, 70, and 100 of each storage battery module 30, 60, and 90 are controlled so that the currents passing through each storage battery module 30, 60, and 90 and the load 21 are set to the corresponding current command values. This series of processes then ends (END).

[0050] Furthermore, if it is determined in S11 that the temperature variation of the storage batteries 31, 61, 91 is not equal to or less than the predetermined value (S11: NO), the system transitions to a heat generation mode (S17). The heat generation mode is a mode in which the above-described current application operation and the above-described temperature increase operation are performed. A heat generation target battery is selected (S18). The heat generation target battery is a battery for which the temperature increase operation is to be performed. For example, the temperature of the battery with the highest temperature among the storage batteries 31, 61, 91 is set as the reference temperature, and a battery whose temperature difference from the reference temperature is greater than a predetermined value is selected as the heat generation target battery.

[0051] Next, it is determined whether the number of heat generation target batteries is two or more (S19). If it is determined that the number of heat generation target batteries is not two or more (S19: NO), the process proceeds to S16. In this case, in the process of S16, the unequal distribution value allocated to the battery module corresponding to the heat generation target battery is set to be greater than the unequal distribution value allocated to the other battery modules. That is, the power ratios of the batteries 31, 61, and 91 during the energization operation are adjusted based on the temperatures of the batteries 31, 61, and 91 acquired through the processes of S11, S18, and S16.

[0052] On the other hand, if it is determined that the number of heat generation target batteries is two or more (S19: YES), the AC heat generation current of the heat generation target batteries is determined (S20). Specifically, the required heat generation amount is calculated based on the temperature difference between the reference temperature and the temperature of the heat generation target batteries. Then, the AC heat generation current of the heat generation target batteries is calculated based on the calculated required heat generation amount. For example, if there are two heat generation target batteries, AC current is exchanged between the two heat generation target batteries, and the maximum current value allowed by the battery modules corresponding to the two heat generation target batteries is selected. The allowed maximum current value is the smaller of the maximum current value that can be input / output by the conversion circuit corresponding to the heat generation target batteries or the maximum current value that can be input / output by the heat generation target batteries. Next, the required internal resistance value of the battery required to satisfy the required heat generation amount at the selected current value is calculated. Furthermore, the AC current frequency that can satisfy the calculated required battery internal resistance value is selected by referring to the "internal resistance vs. frequency" characteristic graph of Figure 4. The current amplitude is selected based on the required heat generation amount by referring to the graph of the "heat generation amount vs. current amplitude" characteristic in FIG. 5 for the selected AC current frequency. However, in the "heat generation amount vs. current amplitude" characteristic in FIG. 5, the heat generation amount must be within the AC Win / Wout constraint, which is a characteristic of the storage battery. For example, the AC Win / Wout constraint of the storage batteries 31, 61, and 91 increases as the temperature increases up to the upper limit of the appropriate temperature range of the storage batteries 31, 61, and 91. Furthermore, the higher the SOC [%] of the storage batteries 31, 61, and 91, the smaller the upper limit of AC Win and the larger the upper limit of AC Wout. If the AC Win / Wout constraint is exceeded, the AC frequency is increased (using a frequency with a low internal resistance of the storage battery) or the current amplitude is reduced to correct it within the AC Win / Wout constraint. In this way, the AC heat generation current is determined by selecting the AC frequency and AC amplitude. If there are three heat generation target batteries, AC current may be exchanged between the three heat generation target batteries. If there are four heat generation target batteries, AC current may be exchanged between the four heat generation target batteries, or two pairs of two heat generation target batteries may be formed to exchange AC current. The AC heat generation current of batteries that are not heat generation target batteries is set to 0.

[0053] The processes of S21 and S22 are the same as the processes of S13 and S 14. If it is determined in S22 that the SOH variations of the storage batteries 31, 61, 91 are equal to or less than the predetermined value (S22: YES), the process proceeds to S23.

[0054] In the process of S23, the current command value obtained by adding the AC heat generation current to an evenly distributed value obtained by evenly distributing the load current (discharging current or charging current) required for the load 21 is issued to each storage battery module 30, 60, 90. Then, the conversion circuits 40, 70, 100 of each storage battery module 30, 60, 90 are controlled so that the current flowing through each storage battery module 30, 60, 90 and the load 21 becomes the current command value. After that, this series of processes is temporarily ended (END).

[0055] On the other hand, if it is determined that the SOC variation of the storage batteries 31, 61, 91 is not below the predetermined value (S21: NO), and if it is determined that the SOH variation of the storage batteries 31, 61, 91 is not below the predetermined value (S22: NO), the process proceeds to S24.

[0056] In the process of S24, a current command value is issued to each storage battery module 30, 60, 90, which is the sum of the AC heat generation current and an unequal distribution value obtained by unevenly distributing the load current (discharging current or charging current) required for the load 21. The method for setting the unequal distribution value is the same as in the process of S16. Then, the conversion circuits 40, 70, 100 of each storage battery module 30, 60, 90 are controlled so that the currents flowing through each storage battery module 30, 60, 90 and the load 21 become equal to the current command values. After that, this series of processes is temporarily ended (END).

[0057] The process of S10 corresponds to the process performed by the status acquisition unit 16e, the processes of S15, S16, S23, and S24 correspond to the process performed by the current application execution unit, and the processes of S23 and S24 correspond to the process performed by the temperature increase execution unit.

[0058] FIG. 6 is a schematic diagram showing an example of the discharge operation (current application operation) and the heating operation. In FIG. 6, the current due to the discharge operation is represented by a solid arrow, and the current due to the heating operation is represented by a hollow arrow. This same representation applies to subsequent figures. The third storage battery module 90 performs only the discharge operation, while the storage battery modules 30 and 60 perform both the discharge operation and the heating operation. Specifically, the storage battery module 90 is commanded the equal distribution value as the current command value (AC heat generation current = 0), and the storage battery modules 30 and 60 are commanded the current command value equal to the equal distribution value plus the AC heat generation current. In this case, the current shown in FIG. 7 flows through each storage battery 31, 61, and 91 in each storage battery module 30, 60, and 90.

[0059] FIG. 8 is a time chart showing the transitions in the operating state, battery temperature, and battery SOC [%] of each battery module 30, 60, and 90 in the cases shown in FIGS. 6 and 7 . As shown in FIG. 8( b), the temperature of the first battery 31 (shown by the solid line) and the temperature of the second battery 61 (shown by the dashed line) rise more rapidly than the temperature of the third battery 91 (shown by the dashed line). As shown in FIG. 8( c), the SOC [%] of the batteries 31, 61, and 91 decreases uniformly, maintaining a small SOC variation. As a result, it becomes easier to use up the remaining capacity of all the batteries 31, 61, and 91.

[0060] FIG. 9 is a time chart showing the transitions of the operating state, battery temperature, and battery SOC [%] of each storage battery module 30, 60, and 90 in the comparative example. In the comparative example, as shown in FIG. 9( a), the third storage battery module 90 is initially stopped, and the storage battery modules 30, 60 discharge to the load 21. As a result, as shown in FIG. 9( b), the temperature of the first storage battery 31 (shown by the solid line) and the temperature of the second storage battery 61 (shown by the dashed line) increase, while the temperature of the third storage battery 91 (shown by the dashed line) remains constant. At this time, as shown in FIG. 9( c), the SOC [%] of the storage batteries 31, 61 decreases, while the SOC [%] of the third storage battery 91 remains unchanged, resulting in increased SOC variation. Then, as shown in FIG. 9( b), when the temperature of the storage batteries 31, 61 becomes equal to the temperature of the third storage battery 91, the third storage battery module 90 starts discharging to the load 21, as shown in FIG. 9( a). As a result, although the temperatures of the storage batteries 31, 61, and 91 rise uniformly, the SOC variations remain large as shown in FIG. 9(c).

[0061] 10 is a schematic diagram showing another example of the execution of the current application operation and the temperature increase operation. The battery modules 30 and 60 are only performing the temperature increase operation, and the third battery module 90 is only performing the discharge operation. For example, the operation shown in FIG. 10 is executed when only the third battery 91 is at a temperature at which it can discharge to the load 21, only the third battery 91 is discharging, and the temperature of the third battery 91 is higher than the temperature of the batteries 31 and 61 by a specified value or more.

[0062] The present embodiment described above in detail has the following advantages.

[0063] The positive and negative electrodes of the storage batteries 31, 61, 91 are connected to the primary terminal pairs 41, 42, 71, 72, 101, 102 of the conversion circuit 40, 70, 100, respectively, and the storage batteries 31, 61, 91 are connected in series to the secondary terminal pairs 47, 48, 77, 78, 107, 108 of the conversion circuit 40, 70, 100. With this configuration, the output voltage Vm of the storage battery module 30, 60, 90 is the sum of the output voltage Vb of the storage battery 31, 61, 91 and the output voltage Vo of the conversion circuit 40, 70, 100. Therefore, compared to a storage battery module in which storage batteries 31, 61, 91 are connected in parallel to secondary-side terminal pairs 47, 48, 77, 78, 107, 108 of the conversion circuit 40, 70, 100, it is possible to lower the output voltage Vo required of the conversion circuit 40, 70, 100 when an output voltage Vm is required of the storage battery module 30, 60, 90. Therefore, the rated voltage of the conversion circuit 40, 70, 100 can be lowered, and therefore the rated capacity of the conversion circuit 40, 70, 100 can be reduced, thereby enabling the conversion circuit 40, 70, 100 to be made smaller.

[0064] The energization execution unit 16c controls the conversion circuits 40, 70, and 100 of the multiple storage battery modules 30, 60, and 90, respectively, to perform an energization operation between the storage batteries 31, 61, and 91 and the load 21. This allows the temperature of the storage batteries that have performed the energization operation with the load 21 to be increased. Furthermore, the temperature-raising execution unit 16d controls the conversion circuits 40, 70, and 100 of the multiple storage battery modules 30, 60, and 90, respectively, to perform a temperature-raising operation to increase the temperatures of the multiple storage batteries 31, 61, and 91 by charging and discharging between the multiple storage batteries 31, 61, and 91. This allows the temperature of the multiple storage batteries that have performed the temperature-raising operation to be increased separately from the temperature-raising operation between the storage batteries 31, 61, and 91 and the load 21. Furthermore, the power supply system 10 simultaneously performs the energization operation by the energization execution unit 16c and the temperature-raising operation by the temperature-raising execution unit 16d. Therefore, the temperature of the storage battery 31, 61, 91 can be flexibly adjusted while current is being passed between the storage battery 31, 61, 91 and the load 21. In particular, for example, while the storage battery 31, 61, 91 is discharging to the load 21, the temperature of the storage battery 31, 61, 91 can be made uniform or can be quickly increased.

[0065] The energization execution unit 16c adjusts the power ratio of the multiple storage batteries 31, 61, 91 during energization based on the states of the multiple storage batteries 31, 61, 91 acquired by the BMUs 32, 62, 92. With this configuration, the power ratio of the multiple storage batteries 31, 61, 91 during energization is adjusted based on the states of the multiple storage batteries 31, 61, 91, so the temperatures of the storage batteries 31, 61, 91 can be adjusted more flexibly through the energization operation by the energization execution unit 16c.

[0066] The energization execution unit 16c adjusts the power ratios of the multiple storage batteries 31, 61, 91 in the energization operation so as to reduce the difference in SOC [%] between the multiple storage batteries 31, 61, 91 obtained by the BMUs 32, 62, 92. With this configuration, the energization operation by the energization execution unit 16c not only allows current to flow between the storage batteries 31, 61, 91 and the load 21, but also reduces the difference in SOC [%] between the multiple storage batteries 31, 61, 91.

[0067] The energization execution unit 16c increases the power ratio in the energization operation for a storage battery with a higher SOH [%] acquired by the BMU 32, 62, 92. With this configuration, the energization operation by the energization execution unit 16c not only energizes the storage battery 31, 61, 91 and the load 21, but also reduces the difference in SOH [%] among the multiple storage batteries 31, 61, 91. In other words, by increasing the energization power in the energization operation for a storage battery with a higher SOH [%], the difference in SOH [%] between the storage batteries and the other storage batteries can be reduced.

[0068] The temperature increase execution unit 16d determines the heat generation target battery based on the status of the plurality of storage batteries 31, 61, 91 acquired by the status acquisition unit 16e. With this configuration, the heat generation target battery can be appropriately determined based on the status of the plurality of storage batteries 31, 61, 91.

[0069] The above-described advantageous effects can be achieved by causing a computer to execute the control program applied to the power supply system 10 .

[0070] The above embodiment can be modified as follows: The same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0071] The status acquisition unit 16e may acquire the states and power distribution schedules of the multiple storage batteries 31, 61, 91 as the statuses of the multiple storage batteries 31, 61, 91, and the temperature increase execution unit 16d may determine the heat generation target storage batteries based on the states and power distribution schedules of the multiple storage batteries 31, 61, 91 acquired by the status acquisition unit 16e. This configuration allows the heat generation target storage batteries to be appropriately determined taking into account the states and power distribution schedules of the multiple storage batteries 31, 61, 91. In FIG. 11 , the first storage battery module 30 performs only a temperature increase operation, the second storage battery module 60 performs a discharge operation and a temperature increase operation, and the third storage battery module 90 performs only a discharge operation. For example, by determining the first storage battery 31, which is scheduled to perform a discharge operation to the load 21 and requires a temperature increase, as the heat generation target storage battery, the discharge operation from the first storage battery 31 to the load 21 can be promptly started. 12 , the battery modules 30 and 60 are only performing a temperature increase operation, and the third battery module 90 is performing a discharge operation and a temperature increase operation. For example, by determining the battery 31 or 61 that is scheduled to be discharged to the load 21 and that needs to be heated as the heat generation target battery, the discharge operation from the battery 31 or 61 to the load 21 can be started promptly.

[0072] The temperature rise execution unit 16d may determine, as the heat generation target battery, a battery whose power upper limit (transmittable power) as the current constraint Win / Wout of the battery increases by a larger amount before and after the temperature rise operation than the other batteries. In FIG. 13 , the first battery module 30 is stopped, and the battery modules 60 and 90 are performing a discharging operation and a temperature rise operation. For example, the operation shown in FIG. 13 is executed when the increase in the transmittable power of the battery 61 and 91 before and after the temperature rise operation for a predetermined time is larger than the increase in the first battery 31. With this configuration, the transmittable power of the battery 61 and 91 can be effectively increased by the temperature rise operation, thereby effectively improving the current carrying capacity of the power supply system 10.

[0073] The status acquisition unit 16e may acquire the SOH [%] of the multiple storage batteries 31, 61, 91 as the status of the multiple storage batteries 31, 61, 91, and the temperature increase execution unit 16d may select a storage battery with a higher SOH [%] acquired by the status acquisition unit 16e than the other storage batteries as the execution target. In FIG. 14 , the first storage battery module 30 performs only the temperature increase operation, the second storage battery module 60 performs the discharge operation and the temperature increase operation, and the third storage battery module 90 is stopped. For example, the operation shown in the figure is executed when the SOH [%] of the first storage battery 31 is higher than the SOH [%] of the third storage battery 91. With this configuration, the temperature increase execution unit 16d not only increases the temperature of the storage batteries 31, 61 but also reduces the difference in SOH [%] among the multiple storage batteries 31, 61, 91. That is, by actively performing a temperature raising operation on a storage battery having a higher SOH [%] than the other storage batteries, the difference in SOH [%] from the other storage batteries can be reduced.

[0074] The status acquisition unit 16e may acquire the physical layout of the storage batteries 31, 61, 91 as the status of the storage batteries 31, 61, 91. The temperature increase execution unit 16d may determine, based on the physical layout of the storage batteries 31, 61, 91 acquired by the status acquisition unit 16e, a storage battery that receives less heat from the outside than the other storage batteries or a storage battery that dissipates heat to the outside more easily than the other storage batteries, as a heat generation target storage battery. In FIG. 15 , the storage battery modules 30, 60 only perform a temperature increase operation, and the third storage battery module 90 is stopped. For example, the operation shown in FIG. 15 is executed when the storage battery 31, 61 receives less heat from the outside than the third storage battery 91. With this configuration, the storage battery 31, 61, which heats up more slowly than the third storage battery 91 or cools down more easily than the third storage battery 91, can be heated in advance. Alternatively, the operation shown in FIG. 15 is executed when the storage battery 31, 61 dissipates heat to the outside more easily than the third storage battery 91. With this configuration, the storage batteries 31 and 61, which are more likely to cool down than the third storage battery 91, can be heated in advance.

[0075] The temperature-raising execution unit 16d may perform a temperature-raising operation to maintain the temperature of the heat-generation target battery at or above a specified temperature when the outside air temperature is lower than the temperatures of the multiple storage batteries 31, 61, 91. The outside air temperature can be detected by an outside air temperature sensor provided in the vehicle. The specified temperature is set, for example, to a temperature at which the storage batteries 31, 61, 91 can demonstrate their standard current-carrying capacity. In FIG. 16 , the storage battery modules 30, 60, 90 perform only a temperature-raising operation. For example, the operation shown in FIG. 16 is performed when the outside air temperature is lower than the temperature of the storage batteries 31, 61, 91. With this configuration, for example, even if the outside air temperature is lower than the temperature of the multiple storage batteries 31, 61, 91 after the current-carrying operation between the storage batteries 31, 61, 91 and the load 21 is completed, the temperature of the storage batteries 31, 61, 91 can be maintained at or above the specified temperature by the temperature-raising operation. Therefore, when a current-carrying request is made to the power supply system 10, current can be quickly supplied in response to the current-carrying request.

[0076] The temperature increase execution unit 16d may make the SOC [%] of the battery determined as the heat generation target battery higher than the SOC [%] of the other batteries by charging from the load 21 or another battery before executing the temperature increase operation. With this configuration, even if the SOC [%] of the heat generation target battery decreases due to the temperature increase operation, it is possible to prevent the difference in SOC [%] among the multiple batteries 31, 61, 91 from becoming too large.

[0077] As shown in FIG. 17 , the power supply system 210 may include a path 211 connecting a connection point N7 between the third conversion circuit 100 of the third storage battery module 90 and the relay 100a and a connection point N8 between the second storage battery 61 of the second storage battery module 60 and the relay 70b. Furthermore, the power supply system 210 may include a path 213 connecting a connection point N9 between the second conversion circuit 70 of the second storage battery module 60 and the relay 70a and a connection point N10 between the first storage battery 31 of the first storage battery module 30 and the relay 40b. The path 211 is provided with a relay 212 (switch) that connects and disconnects the path 211. The path 213 is provided with a relay 214 (switch) that connects and disconnects the path 213. The relays 212 and 214 are controlled by the ECU 16. The paths 211, 213, and the relays 212 and 214 form a switching circuit. That is, the power supply system 210 may include three or more storage battery modules (a plurality of storage battery modules), and the switching circuit may switch the three or more storage battery modules between a series connection and a parallel connection with respect to the buses 11 and 12. When the switching circuit switches the storage battery modules 30, 60, and 90 to a parallel connection, power can be supplied from the storage battery modules 30, 60, and 90 to the buses 11 and 12. This allows the storage battery modules 30, 60, and 90 to be used as redundant power sources. When the switching circuit switches the storage battery modules 30, 60, and 60 to a parallel connection, the ECU 16 can execute the above-described control of the power supply system 10 and its modifications. When the switching circuit switches the storage battery modules 30, 60, and 90 to a series connection, a voltage equal to the sum of the output voltages Vm1, Vm2, and Vm3 of the storage battery modules 30, 60, and 90 can be supplied to the buses 11 and 12. Therefore, the storage battery modules 30, 60, and 90 can be used as higher voltage power sources.

[0078] The number of storage battery modules included in the power supply system 10, 210 may be two, four or more.

[0079] As the load 21, for example, two or more combinations of an inverter and an MG (Motor Generator) (motor units with inverters) may be connected in parallel to the buses 11 and 12. In this case, the more motor units with inverters there are, the more storage battery modules may be connected to the buses 11 and 12.

[0080] As shown in Fig. 18, in the first conversion circuit 40 (conversion circuit), the switching elements 54 and 55 in Fig. 2 may be connected between the transformer 53 and the negative terminal 48. With this configuration, it is possible to achieve the same effects as the first conversion circuit 40 in Fig. 2. The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuits).

[0081] 19, the first conversion circuit 40 (conversion circuit) may be a well-known isolated DC-DC converter including a non-center-tapped transformer 153 and a secondary-side full-bridge circuit composed of switching elements 143 to 146. The switching elements 143 to 146 are, for example, MOSFETs or IGBTs (Insulated Gate Bipolar Transistors). The switching elements 143 to 146 are controlled by the ECU 16. The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuits).

[0082] A resonant DC-DC converter may be used as the first conversion circuit 40 (conversion circuit). Also, a non-isolated DC-DC converter such as a buck converter may be used as the first conversion circuit 40 (conversion circuit). The same applies to the second conversion circuit 70 and the third conversion circuit 100 (conversion circuit).

[0083] The storage battery modules 30, 60, 90 may be configured as shown in FIG. 20 . That is, the positive electrode of the first storage battery 31 is connected to the bus 11. The positive electrode of the first storage battery 31 is connected to the primary-side positive terminal 41 of the first conversion circuit 40, and the negative electrode of the first storage battery 31 is connected to the primary-side negative terminal 42 of the first conversion circuit 40. The negative electrode of the first storage battery 31 is connected to the secondary-side positive terminal 47 of the first conversion circuit 40. The secondary-side negative terminal 48 of the first conversion circuit 40 is connected to the bus 12. In this case, too, the positive and negative electrodes of the first storage battery 31 are connected to the primary-side terminal pair 41, 42 of the first conversion circuit 40, respectively, and the first storage battery 31 is connected in series to the secondary-side terminal pair 47, 48 of the first conversion circuit 40. With this configuration, the same effects as those of the above embodiment can be achieved. The same applies to the second storage battery module 60, the third storage battery module 90, etc. (storage battery modules).

[0084] At least one of the functions of the bus voltage setting unit 16 a, the control unit 16 b, the energization execution unit 16 c, the temperature increase execution unit 16 d, and the status acquisition unit 16 e of the ECU 16 can also be realized by the BMU 32, 62, 92, the drive circuit 35, 65, 95, a power control ECU (Electronic Control Unit) that controls the power of the electric vehicle, or a vehicle control ECU (host ECU) that controls the electric vehicle overall. Furthermore, when the power supply system 10, 210 is used as, for example, a stationary power source, the functions of the bus voltage setting unit 16 a, the control unit 16 b, the energization execution unit 16 c, the temperature increase execution unit 16 d, and the status acquisition unit 16 e of the ECU 16 can also be realized by a stationary power source control ECU (control device) that controls the stationary power source.

[0085] The ECU 16 and the methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions (instructions) embodied in a computer program. Alternatively, the ECU 16 and the methods described herein may be implemented by a special-purpose computer configured with a processor implemented by one or more dedicated hardware logic circuits. Alternatively, the ECU 16 and the methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to execute one or more functions and a processor implemented by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0086] The above-described embodiment and modifications may be combined within the scope of possible combinations.

[0087] Characteristic configurations extracted from the above-described embodiment and modified examples will be described below. [Configuration 1] A power supply system (10, 210) in which a plurality of storage battery modules (30, 60, 90) including storage batteries (31, 61, 91) and conversion circuits (40, 70, 100) that convert power input from the storage batteries to primary-side terminal pairs (41, 42, 71, 72, 101, 102) and output the converted power from secondary-side terminal pairs (47, 48, 77, 78, 107, 108) and a load (21) are connected in parallel to a power supply bus (11, 12), the positive and negative electrodes of the storage batteries being connected to the primary-side terminal pairs of the conversion circuit, respectively, and the storage batteries being connected in series to the secondary-side terminal pairs of the conversion circuit, and a current supply execution unit (16c) that controls the conversion circuits of the plurality of storage battery modules to respectively perform a current supply operation between the storage batteries and the load, and a temperature-raising execution unit (16d) that controls the conversion circuits of the plurality of storage battery modules to respectively perform a temperature-raising operation to raise the temperatures of the plurality of storage batteries by charging and discharging among the plurality of storage batteries, wherein the current-carrying operation by the current-carrying execution unit and the temperature-raising operation by the temperature-raising execution unit are simultaneously performed. [Configuration 2] The power supply system according to Configuration 1, further comprising a status acquisition unit (32, 62, 92) that acquires states of the plurality of storage batteries, wherein the current-carrying execution unit adjusts a power ratio of the plurality of storage batteries in the current-carrying operation based on the states of the plurality of storage batteries acquired by the status acquisition unit. [Configuration 3] The power supply system according to Configuration 2, wherein the status acquisition unit acquires charging rates of the plurality of storage batteries as the states of the plurality of storage batteries, and the current-carrying execution unit adjusts the power ratio of the plurality of storage batteries in the current-carrying operation so as to reduce a difference in the charging rates of the plurality of storage batteries acquired by the status acquisition unit. [Configuration 4] The power supply system according to Configuration 2 or 3, wherein the status acquisition unit acquires health statuses of the plurality of storage batteries as the statuses of the plurality of storage batteries, and the energization execution unit increases the power ratio in the energization operation for a storage battery having a higher health status acquired by the status acquisition unit.[Configuration 5] The power supply system according to any one of Configurations 1 to 4, further comprising a status acquisition unit (16e) that acquires statuses of the plurality of storage batteries, which statuses are at least one of a state, a physical arrangement, and a planned energization date, and the temperature increase execution unit determines a storage battery as a target for the temperature increase operation based on the statuses of the plurality of storage batteries acquired by the status acquisition unit. [Configuration 6] The power supply system according to Configuration 5, further comprising: the status acquisition unit acquires health statuses of the plurality of storage batteries as the statuses of the plurality of storage batteries; and the temperature increase execution unit determines a storage battery as a target for the execution, the health status acquired by the status acquisition unit being higher than that of the other storage batteries. [Configuration 7] The power supply system of Configuration 5, wherein the status acquisition unit acquires a physical arrangement of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines, as the execution target, a storage battery that receives less heat from the outside than the other storage batteries or a storage battery that radiates heat to the outside more easily than the other storage batteries, based on the physical arrangement of the multiple storage batteries acquired by the status acquisition unit. [Configuration 8] The power supply system of Configuration 7, wherein the heating execution unit executes the heating operation to keep the temperature of the storage battery determined to be the execution target at or above a specified temperature when the outside air temperature is lower than the temperatures of the multiple storage batteries. [Configuration 9] The power supply system of Configuration 5, wherein the status acquisition unit acquires the states and the power distribution schedule of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines the storage battery to be the execution target of the heating operation, based on the states and the power distribution schedule of the multiple storage batteries acquired by the status acquisition unit. [Configuration 10] The power supply system according to Configuration 9, wherein the temperature rise execution unit determines, as the execution target, a storage battery that has a larger increase in the current-carrying power of the storage battery before and after the execution of the temperature rise operation than other storage batteries. [Configuration 11] The power supply system according to any one of Configurations 5 to 10, wherein the temperature rise execution unit sets the charging rate of the storage battery determined as the execution target higher than the charging rates of the other storage batteries by charging from the load or another storage battery before the temperature rise operation is executed.

[0088] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A power supply system (10, 210) in which a plurality of storage battery modules (30, 60, 90) each including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a pair of primary terminals (41, 42, 71, 72, 101, 102) and outputs the converted power from a pair of secondary terminals (47, 48, 77, 78, 107, 108), and a load (21) are connected in parallel to a power supply bus (11, 12), in which the positive and negative electrodes of the storage battery are respectively connected to the pair of primary terminals of the conversion circuit, and the storage battery is connected in series to the pair of secondary terminals of the conversion circuit, and a current supply execution unit (16c) that controls each of the conversion circuits of the plurality of storage battery modules to execute a current supply operation between the storage battery and the load, a temperature-raising execution unit (16d) that controls the conversion circuits of the plurality of storage battery modules, respectively, to perform a temperature-raising operation of raising the temperatures of the plurality of storage batteries by charging and discharging between the plurality of storage batteries, wherein the current-flow operation by the current-flow execution unit and the temperature-raising operation by the temperature-raising execution unit are performed simultaneously.

2. A power supply system as described in claim 1, further comprising a status acquisition unit (32, 62, 92) that acquires the status of the multiple storage batteries, and the power supply execution unit adjusts the power ratio of the multiple storage batteries in the power supply operation based on the status of the multiple storage batteries acquired by the status acquisition unit.

3. The power supply system of claim 2, wherein the status acquisition unit acquires the charging rates of the multiple storage batteries as the status of the multiple storage batteries, and the current supply execution unit adjusts the power ratio of the multiple storage batteries in the current supply operation so as to reduce the difference in the charging rates of the multiple storage batteries acquired by the status acquisition unit.

4. A power supply system as described in claim 2 or 3, wherein the status acquisition unit acquires the health of the multiple storage batteries as the status of the multiple storage batteries, and the current supply execution unit increases the power ratio in the current supply operation for a storage battery having a higher health status acquired by the status acquisition unit.

5. A power supply system as described in any one of claims 1 to 3, further comprising a status acquisition unit (16e) that acquires at least one of the status, physical arrangement, and planned power supply status of the plurality of storage batteries, and the heating execution unit determines the storage battery for which the heating operation is to be executed based on the status of the plurality of storage batteries acquired by the status acquisition unit.

6. The power supply system of claim 5, wherein the status acquisition unit acquires the health of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines the storage battery whose health status acquired by the status acquisition unit is higher than that of the other storage batteries as the storage battery to be executed.

7. The power supply system of claim 5, wherein the status acquisition unit acquires a physical arrangement of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines, based on the physical arrangement of the multiple storage batteries acquired by the status acquisition unit, as the execution target a storage battery that is less susceptible to heat reception from the outside than the other storage batteries, or a storage battery that is more likely to radiate heat to the outside than the other storage batteries.

8. The power supply system of claim 7, wherein the heating execution unit executes the heating operation so as to keep the temperature of the storage battery determined as the execution target at or above a specified temperature when the outside air temperature is lower than the temperatures of the plurality of storage batteries.

9. The power supply system of claim 5, wherein the status acquisition unit acquires the states and the power supply schedule of the multiple storage batteries as the status of the multiple storage batteries, and the heating execution unit determines the storage battery to be the target of the heating operation based on the states and the power supply schedule of the multiple storage batteries acquired by the status acquisition unit.

10. The power supply system of claim 9, wherein the heating execution unit determines as the execution target the storage battery in which the increase in the available power of the storage battery before and after the heating operation is performed is greater than that of other storage batteries.

11. The power supply system of claim 5, wherein the heating execution unit sets the charging rate of the storage battery determined to be the execution target higher than the charging rates of the other storage batteries by charging from the load or other storage batteries before executing the heating operation.

12. A control device (16) applied to a power supply system (10, 210) in which a plurality of storage battery modules (30, 60, 90) including storage batteries (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage batteries to a pair of primary terminals (41, 42, 71, 72, 101, 102) and outputs the power from a pair of secondary terminals (47, 48, 77, 78, 107, 108) and a load (21) are connected in parallel to a power supply bus (11, 12), the positive and negative electrodes of the storage batteries are respectively connected to the pair of primary terminals of the conversion circuit, and the storage batteries are connected in series to the pair of secondary terminals of the conversion circuit, the control device (16) comprising: a current supply execution unit (16c) that controls each of the conversion circuits of the plurality of storage battery modules to execute a current supply operation between the storage batteries and the load; a temperature rise execution unit (16d) that executes a temperature rise operation to raise the temperatures of the plurality of storage batteries by charging and discharging between the plurality of storage batteries by controlling the conversion circuits of the plurality of storage battery modules, respectively; and 13. A control program applied to a power supply system (10, 210) in which a plurality of storage battery modules (30, 60, 90) including a storage battery (31, 61, 91) and a conversion circuit (40, 70, 100) that converts power input from the storage battery to a primary terminal pair (41, 42, 71, 72, 101, 102) and outputs the power from a secondary terminal pair (47, 48, 77, 78, 107, 108) and a load (21) are connected in parallel to a power supply bus (11, 12), the positive and negative electrodes of the storage battery are respectively connected to the primary terminal pair of the conversion circuit, and the storage battery is connected in series to the secondary terminal pair of the conversion circuit, the control program comprising: a process of executing a current supply operation between the storage battery and the load by controlling each of the conversion circuits of the plurality of storage battery modules; and a process of performing a heating operation to heat up the storage batteries by charging and discharging between the storage batteries by controlling the conversion circuits of the storage battery modules respectively.

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