JP7177124B2 - Battery control system and computer program - Google Patents

Description

The present invention relates to a battery control system that combines and discharges a plurality of battery packs.

2. Description of the Related Art Machines that operate on power supplied from a battery include, for example, electric vehicles and electric assist vehicles. Generally, these vehicles are equipped with a battery, and the electric motor is rotated by electric power supplied from the battery, so that the vehicle can run. The battery is rechargeable and can be used repeatedly by charging.

In recent years, it has been proposed to construct a stationary power storage system using a used battery that has been used in a vehicle or the like as described above. A stationary power storage system can be used, for example, in a power generation facility that uses renewable energy, such as a solar power generation facility.

Patent Literature 1 discloses a battery control device that controls a plurality of batteries. In Patent Literature 1, the degree of deterioration of each battery is determined from temperature, SOC, and the like, and the output ratio among a plurality of batteries is adjusted based on the degree of deterioration. Thereby, the charge/discharge amount of each of the plurality of batteries can be appropriately controlled.

Patent Literature 2 discloses a battery control device that determines the degree of deterioration from the internal resistance of the batteries and preferentially discharges the batteries with the lowest degree of deterioration. By preferentially using the battery with the least degree of deterioration, the degree of deterioration of the batteries is made uniform, thereby extending the life of the entire system.

JP 2019-041550 A Japanese Patent No. 4572850

The battery control devices disclosed in Patent Documents 1 and 2 are based on the assumption that a plurality of batteries with the same specifications are used. Due to the same specifications, if there is a difference in measured values such as internal resistance between multiple batteries, a table or map showing the relationship between the measured value and the degree of deterioration can be used to determine the degree of deterioration between the batteries. It is possible to grasp the magnitude relationship between

However, when reusing used batteries, for example, it may be required to use not only batteries with the same specifications but also batteries with different specifications. In this case, it is difficult to evaluate the temperature, SOC, internal resistance, etc. of each battery using the same scale, and it is difficult to determine the relative degree of deterioration of each battery. It is difficult to apply the control methods disclosed in Patent Documents 1 and 2 to a combination of batteries with different specifications, and the degree of freedom in battery selection is low.

The present invention provides a battery control system with improved flexibility in battery selection.

A battery control system according to an embodiment of the present invention is a battery control system comprising: a plurality of connection devices to which a plurality of battery packs are connected; and a control device for controlling operations of the plurality of battery packs. , the control device obtains a first upper limit output of each of the plurality of battery packs, and uses the first upper limit output of the plurality of battery packs to obtain a second upper limit output of a battery unit including the plurality of battery packs. and controlling the operation of the plurality of battery packs based on the calculated second upper limit output of the battery unit.

In the present invention, the second upper limit outputs of the battery units are calculated using the first upper limit outputs of the plurality of battery packs, and the plurality of battery packs are controlled based on the calculated second upper limit outputs of the battery units.

Regardless of whether the specifications of the plurality of battery packs are the same or different, the upper limit output can be obtained for each battery pack, and the discharge of the combined battery packs is controlled based on this upper limit output. Even if a plurality of battery packs have mutually different specifications, the upper limit output is a common physical quantity among the battery packs. Therefore, by evaluating each battery pack using the upper limit output, even if the specifications of a plurality of battery packs differ from each other, the battery packs can be combined with each other. As a result, the degree of freedom in selecting battery packs can be improved.

In one embodiment, even if the discharge of at least one of the plurality of battery packs is restricted, the second upper limit output of the battery unit is larger than the power consumption of the load connected to the battery control system. , the control device may perform control to limit discharge of the at least one battery pack.

When limiting the discharge of at least one battery pack yields an upper limit output that is greater than the power consumption of the load, by limiting the discharge of at least one battery pack, the plurality of battery packs can be effectively used. can be used. For example, deterioration of the battery pack that limits its discharge can be suppressed.

In one embodiment, the plurality of battery packs are three or more battery packs, and the control device controls the third upper limit output of each of a plurality of groups obtained by combining two or more of the plurality of battery packs. may be calculated, and a third upper limit output that is the largest among the third upper limit outputs of the plurality of groups may be set as the second upper limit output of the battery unit.

Depending on the states of the plurality of battery packs, the upper limit output may not necessarily increase as the number of combined battery packs increases. A third upper limit output is calculated for each of a plurality of groups in which the combination of battery packs is different from each other, and the maximum upper limit output among them is set as the second upper limit output of the battery unit. By adopting the maximum upper limit output obtained from a combination of a plurality of battery packs, it is possible to perform discharge that maximizes the capabilities of the plurality of battery packs.

In one embodiment, a first group, which is one of the plurality of groups, includes a first battery pack, and the control device selects a battery having the lowest voltage among the battery packs included in the first group. When the pack is the first battery pack, the voltage of the first battery pack is set as a reference voltage, and the ratio of each of the voltages of the other battery packs included in the first group to the reference voltage is calculated. Then, based on the calculated ratio, the duty ratio to be applied to each of the other battery packs is calculated, and the first upper limit output of each of the other battery packs when the calculated duty ratio is applied is calculated. , a value obtained by adding the calculated first upper limit output of the other battery pack and the first upper limit output of the first battery pack may be obtained as the third upper limit output of the first group.

The voltage output from each battery pack included in the first group can be adjusted to have the same magnitude, and the battery packs included in the first group can be connected in parallel and discharged. In addition, the third upper limit output of the first group can be obtained in a mode in which the battery packs included in the first group are connected in parallel and discharged.

By performing the above calculation for each of the plurality of groups, it is possible to obtain the third upper limit output of each of the plurality of groups.

In one embodiment, even if discharge of at least one of the battery packs included in the group having the largest third upper limit output among the plurality of groups is limited, the battery pack connected to the battery control system When the second upper limit output of the battery unit is larger than the power consumption of the load, the control device may perform control to limit discharge of the at least one battery pack.

When limiting the discharge of at least one battery pack yields an upper limit output that is greater than the power consumption of the load, by limiting the discharge of at least one battery pack, the plurality of battery packs can be effectively used. can be used. For example, deterioration of the battery pack that limits its discharge can be suppressed.

In one embodiment, the control device selects, from among the plurality of groups, one group in which the third upper limit output is greater than the power consumption of a load connected to the battery control system, and the selected group may be controlled to discharge the battery pack included in the.

This makes it possible to supply the required power to the load.

In one embodiment, when there are two or more groups among the plurality of groups in which the third upper limit output is greater than the power consumption of the load connected to the battery control system, the control device controls the plurality of control to select one group having the third upper limit output larger than the power consumption, other than the group having the maximum third upper limit output, among the groups, and discharging the battery packs included in the selected group. may be performed.

A plurality of battery packs can be efficiently used by selecting a group other than the group that maximizes the third upper limit output. For example, by selecting a group that does not use one or more of the plurality of battery packs, deterioration of the unused battery packs can be suppressed.

In one embodiment, when selecting one group from the plurality of groups, the control device selects a group that does not include the battery pack with the smallest first upper limit output among the plurality of battery packs. and control to discharge the battery packs included in the selected group.

It is conceivable that a battery pack with a small first upper limit output has a small remaining capacity or has advanced deterioration. By not using a battery pack with a small first upper limit output for discharging, stable discharging can be performed. Also, for a battery pack with a small remaining capacity, it is possible to give priority to charging over discharging. Moreover, deterioration of the unused battery pack can be suppressed.

In one embodiment, when selecting one group from the plurality of groups, the control device selects a group that does not include a battery pack having the maximum first upper limit output among the plurality of battery packs. and control to discharge the battery packs included in the selected group.

It is conceivable that a battery pack with a large first upper limit output has a large remaining capacity or is not degraded. When the battery control system is used, for example, as a charging station for an electric vehicle, it is desirable that the battery pack to be replaced with an empty battery pack mounted on the electric vehicle have a large remaining capacity. In addition, it is desirable that an electric vehicle is equipped with a battery pack whose deterioration has not progressed.

By not using the battery pack with the large first upper limit output for discharging in the battery control system, the battery pack can be mounted on the electric vehicle. Further, even when a battery pack with a large upper limit output is removed from the battery control system in order to be mounted on an electric vehicle, the discharging operation of the battery control system can be continued.

In one embodiment, when discharging a battery pack included in a group selected from the plurality of groups, the control device controls the voltage of the battery pack having the lowest voltage among the battery packs included in the selected group. may be set as the reference voltage, and each of the voltages output from the other battery packs included in the selected group may be adjusted to the reference voltage.

By adjusting the voltage output from each of the battery packs included in the group selected for discharge to the same magnitude, the battery packs included in the group can be connected in parallel and discharged.

In one embodiment, the control device may adjust each of the voltages output from the other battery packs to the reference voltage by PWM (Pulse Width Modulation) control.

By PWM control, the voltages output from each battery pack can be adjusted to the same magnitude as each other.

In one embodiment, the battery packs included in the selected group are discharged while being connected in parallel, and among the battery packs not included in the selected group, the battery packs having output voltages lower than the reference voltage are selected. A positive terminal may be connected to a node of the parallel connection via a diode.

A sudden change in load magnitude can cause a sudden drop in the output voltage of the battery control system. When the output voltage of the battery control system becomes lower than the output voltage of the non-selected battery pack connected through the diode, the non-selected battery pack will also supply power to the load. This can prevent the battery control system from going down.

In one embodiment, in the process of discharging the battery packs included in the selected group, if the magnitude relationship of the third upper limit outputs of the plurality of groups changes, the control device may change the group to be discharged. good.

As the remaining capacity of the battery pack decreases due to discharging, the magnitude relationship between the third upper limit outputs of the groups changes. In this case, by changing the group to be discharged, it is possible to discharge in a more appropriate group.

In one embodiment, the control device calculates a first upper limit output of the battery pack based on a detected voltage value of the battery pack and an upper limit current of the battery pack corresponding to the detected voltage value. may

A second upper limit output of a battery unit including a plurality of battery packs can be calculated using the calculated first upper limit output of the battery pack.

In one embodiment, at least one of the plurality of battery packs may have specifications different from other battery packs.

By combining battery packs using the upper limit output, battery packs with different specifications can be combined. As a result, the degree of freedom in selecting battery packs can be improved.

A computer program according to an embodiment of the present invention is a computer program that causes a computer to control operations of a plurality of battery packs, the computer program obtaining a first upper limit output of each of the plurality of battery packs. using the first upper limit outputs of the plurality of battery packs to calculate a second upper limit output of the battery unit including the plurality of battery packs; and based on the calculated second upper limit output of the battery unit, The computer is caused to control operations of a plurality of battery packs.

According to the battery control system according to an embodiment of the present invention, the second upper limit output of the battery unit is calculated using the first upper limit output of the plurality of battery packs, and based on the calculated second upper limit output of the battery unit to control the operation of multiple battery packs. Regardless of whether the specifications of the plurality of battery packs are the same or different, the upper limit output can be obtained for each battery pack, and the discharge of the combined battery packs is controlled based on this upper limit output. Even if a plurality of battery packs have mutually different specifications, the upper limit output is a common physical quantity among the battery packs. Therefore, by evaluating each battery pack using the upper limit output, even if the specifications of a plurality of battery packs differ from each other, the battery packs can be combined with each other. As a result, the degree of freedom in selecting battery packs can be improved.

1 is a perspective view showing a battery control system 1 according to an embodiment of the invention; FIG. 1 is a perspective view showing how a battery pack 10 is attached and detached in the battery control system 1 according to the embodiment of the present invention; FIG. 1 is a diagram showing a battery control system 1 and a battery pack 10 according to an embodiment of the invention; FIG. 4 is a flow chart showing the discharging operation of the battery control system 1 according to the embodiment of the present invention; 4 is a flow chart showing processing for calculating a second upper limit output of the battery unit 20 according to the embodiment of the present invention; FIG. 4 is a diagram showing an example of calculation of a second upper limit output of the battery unit 20 according to the embodiment of the invention; FIG. 7 is a diagram showing another example of calculation of the second upper limit output of the battery unit 20 according to the embodiment of the invention; FIG. 3 is a diagram showing multiple groups resulting from multiple battery packs 10 according to an embodiment of the present invention; 9 is a flowchart showing a process of changing the group to be discharged when the magnitude relationship of the third upper limit outputs among the groups changes according to the embodiment of the present invention. 4 is a flowchart showing a process of changing the group to be discharged according to the magnitude relationship between the second upper limit output of the battery unit 20 and the power consumption of the load 71 according to the embodiment of the present invention.

A battery control system according to an embodiment of the present invention will be described below with reference to the drawings. In the description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted when overlapping. The following embodiments are examples, and the present invention is not limited to the following embodiments.

FIG. 1 is a perspective view showing a battery control system 1 according to an embodiment of the invention. The battery control system 1 performs charging and discharging by combining a plurality of battery packs 10 . The battery control system 1 is used, for example, as a stationary power storage system. Stationary power storage systems can be used, for example, in power generation facilities that utilize renewable energy, such as solar power generation facilities and wind power generation facilities. In addition, the stationary power storage system can also be used as an emergency power source in the event of a disaster or the like.

A battery control system 1 includes a housing 2 and a plurality of connectors (connecting devices) 3 provided in the housing 2 . The number of connectors 3 is any number of two or more. A battery pack 10 is connected to each of the plurality of connectors 3 . One or more battery packs 10 out of the plurality of battery packs 10 form a battery unit 20, and the battery control system 1 discharges the battery unit 20 as a unit.

A housing 2 of the battery control system 1 is provided with a charging connector 4 and discharging connectors 5 and 6 . The charging connector 4 is connected to, for example, a power generation device such as a solar power generation device and a wind power generation device, and can charge the battery pack 10 with electric power generated by the power generation device. Further, for example, the battery pack 10 may be charged by connecting the charging connector 4 to an arbitrary power source such as a household power source.

Discharge connectors 5 and 6 are connected to, for example, a load (external device). Electric power output from the battery pack 10 forming the battery unit 20 is output from the discharge connectors 5 and 6 . DC power is output from the discharge connector 5 . AC power is output from the discharge connector 6 . Depending on the application of the battery control system 1, the battery control system 1 may have only one of the discharge connectors 5 and 6. FIG.

Each battery pack 10 is removable from the battery control system 1 . FIG. 2 is a perspective view showing attachment and detachment of one battery pack 10 in the battery control system 1. FIG. Battery control system 1 charges battery pack 10 connected to connector 3 . For example, the charged battery pack 10 can be removed from the battery control system 1, mounted on a machine such as an electric vehicle and an electric assist vehicle, and used as a power source. In the vehicle equipped with the battery pack 10, the electric motor is rotated by the electric power supplied from the battery pack 10, and the vehicle can run.

The battery pack 10 that has been used in the vehicle and has run out of remaining capacity can be removed from the vehicle and connected to the connector 3 of the battery control system 1 to be charged. Then, by removing another charged battery pack 10 from the battery control system 1 and attaching it to the vehicle, the vehicle can run again. In this way, the battery control system 1 can be used as a charging station for replacing an empty battery pack 10 installed in a vehicle with a charged battery pack 10 .

FIG. 3 is a diagram showing the battery control system 1 and the battery pack 10. As shown in FIG.

In order to explain the embodiments of the present invention in an easy-to-understand manner, the following description will mainly describe a configuration in which three battery packs 10 are connected to the battery control system 1, but the embodiments of the present invention are not limited thereto. The number of battery packs 10 connected to the battery control system 1 is arbitrary, and may be two or four or more, and the present invention can be applied to those forms. In the example shown in FIG. 3, three battery packs 10a, 10b, and 10c are connected to the battery control system 1 as the battery packs 10. FIG.

The battery pack 10 includes a plurality of single cells (cells) 11 , a battery management system (BMS) 12 and a connector 13 . The BMS 12 controls various operations such as charging and discharging of the battery pack 10 and monitors various states of the battery pack 10 . The BMS 12 monitors the voltage, current, temperature, SOC (State of Charge), SOH (State of Health), etc. of the battery pack 10 . The battery pack 10 is connected to the battery control system 1 by connecting the connector 13 of the battery pack 10 to the connector 3 of the battery control system 1 . Current output from the plurality of cells 11 is supplied to the battery control system 1 via the BMS 12 and connector 13 .

In the battery control system 1, a plurality of battery packs 10a, 10b, 10c are connected in parallel with each other. Battery pack 10a is connected to converter 41 and inverter 42 via switching element 51 for PWM (Pulse Width Modulation), diode 61, and switching element 54 for discharging. Battery pack 10b is connected to converter 41 and inverter 42 via switching element 52 for PWM, diode 62, and switching element 54 for discharging. Battery pack 10c is connected to converter 41 and inverter 42 via switching element 53 for PWM, diode 63, and switching element 54 for discharging.

When a load (external device) 71 is connected to the discharge connector 6 , the inverter 42 converts the input DC voltage into AC voltage and outputs the AC voltage to the load 71 . When a load 71 is connected to the discharge connector 5 , the converter 41 adjusts the magnitude of the input DC voltage and outputs it to the load 71 . Battery control system 1 may include only one of converter 41 and inverter 42 depending on the application of battery control system 1 .

When the power generation device 73 is connected to the charging connector 4 , the power output from the power generation device 73 is input to the charger 43 via the charging connector 4 and the switching element 55 for charging. Charger 43 adjusts the magnitude of voltage and current and outputs them to battery pack 10 . When charging the battery pack 10a, the current output from the charger 43 is supplied to the battery pack 10a via the diode 64 and the connector 3. FIG. When charging the battery pack 10b, the current output from the charger 43 is supplied to the battery pack 10b via the diode 65 and the connector 3. FIG. When charging the battery pack 10c, the current output from the charger 43 is supplied to the battery pack 10c via the diode 66 and the connector 3. FIG.

The switching elements 51, 52, 53, 54, 55 are, for example, field effect transistors (FETs), but the switching elements are not limited to field effect transistors, and any switching elements can be used.

Control device 30 controls the operation of battery control system 1 . The control device 30 includes a processor 31 , a memory 32 and a communication circuit 33 . The processor 31 is a signal processing circuit (computer) that controls the operation of the battery control system 1 . Processor 31 is typically a semiconductor integrated circuit.

The memory 32 stores computer programs for causing the processor 31 to control the operation of the battery control system 1 . Such a computer program may be installed in the battery control system 1 from a recording medium (semiconductor memory, optical disk, etc.) in which it is recorded, or may be downloaded via an electric communication line such as the Internet. Also, such a computer program may be installed in the battery control system 1 via wireless communication. Such computer programs may be sold as packaged software. Processor 31 executes computer programs stored in memory 32 to control the operation of battery control system 1 .

The processor 31 communicates with the BMS 12 of the battery pack 10 via the communication circuit 33 . The processor 31 transmits and receives necessary information to and from the BMS 12 when charging and discharging the battery pack 10 . The processor 31 also receives information such as the voltage, current and temperature of the battery pack 10 from the BMS 12 .

Processor 31 controls operations of converter 41 , inverter 42 , charger 43 , and switching elements 51 , 52 , 53 , 54 , 55 . During the discharging operation of the battery control system 1, the processor 31 turns on the switching element 54. FIG. The processor 31 performs PWM control by repeatedly switching ON and OFF of the switching elements 51 , 52 , 53 . A DC voltage modulated by PWM control is input to converter 41 or inverter 42 . During the charging operation of the battery pack 10, the processor 31 turns on the switching element 55 and controls the operation of the charger 43 to supply power to the battery pack 10 to be charged.

When charging, the switching element corresponding to the battery pack 10 to be charged among the switching elements 51, 52, and 53 may be turned off. For example, the battery pack 10c has the lowest voltage among the battery packs 10a, 10b, and 10c, and the battery pack 10c is to be charged. When the battery pack 10c is charged, the switching element 53 is turned off to prevent the current for charging from flowing to the discharge side of the circuit. Thus, the battery pack 10c can be charged while the battery packs 10a and 10b are being discharged. Thus, in the battery control system 1, charging and discharging can be performed in parallel. It is possible to eliminate the difference between the voltage of the battery pack 10c to be charged and the voltage of the battery packs 10a and 10b to be discharged. and 10b.

When charging, the switching element corresponding to the battery pack 10 to be charged among the switching elements 51, 52, and 53 may be turned on. For example, when charging the battery pack 10c, the switching element 53 is turned on. In this case, part of the charging current flows into the discharging side of the circuit. That is, part of the power output from the charger 43 is used as power for discharging. Since the current output from battery pack 10c to be charged decreases, the difference between the voltage of battery pack 10c and the voltages of battery packs 10a and 10b can be reduced.

Next, the discharging operation of the battery control system 1 will be described in more detail.

FIG. 4 is a flow chart showing the discharging operation of the battery control system 1. As shown in FIG. As described above, in the battery control system 1, the battery unit 20 including one or more battery packs 10 out of the plurality of battery packs 10 is configured, and the battery unit 20 is discharged as one unit.

First, the processor 31 (FIG. 3) acquires the upper limit output of each of the plurality of battery packs 10 connected to the battery control system 1 (step S10). The upper limit output of the battery pack 10 is the upper limit of the power that the battery pack 10 can output. The upper limit output changes according to the current state of battery pack 10 . For example, the upper limit output changes according to SOC, temperature, and the like. In the following description, the upper limit output of the battery pack 10 is expressed as "first upper limit output".

BMS 12 of battery pack 10 detects the voltage of battery pack 10 . The BMS 12 acquires the upper limit current of the battery pack 10 corresponding to the detected voltage value. The upper limit current is the upper limit of the current that the battery pack 10 can output when the voltage of the battery pack 10 is the detected magnitude. For example, the BMS 12 stores in advance a map showing the relationship between voltage and upper limit current. The BMS 12 can obtain the upper limit current from the detected voltage using such a map. The BMS 12 outputs the detected voltage value and the upper limit current value to the processor 31 . The processor 31 obtains the first upper limit output of the battery pack 10 by multiplying the detected voltage value and the upper limit current value. The BMS 12 may acquire the first upper limit output by multiplying the detected voltage value and the upper limit current value, and output the acquired value of the first upper limit output to the processor 31 .

Processor 31 configures battery unit 20 including one or more battery packs 10 out of a plurality of battery packs 10 . The processor 31 calculates the upper limit output of the battery unit 20 (step S11). The upper limit output of the battery unit 20 is the upper limit of the power that the battery unit 20 can output. In the following description, the upper limit output of the battery unit 20 is expressed as "second upper limit output". The processor 31 calculates the upper limit output of the battery unit 20 using, for example, the first upper limit output of each battery pack 10 included in the battery unit 20 .

FIG. 5 is a flow chart showing processing for calculating the second upper limit output of the battery unit 20 . FIG. 6 is a diagram showing an example of calculation of the second upper limit output of the battery unit 20. As shown in FIG. FIG. 7 is a diagram showing another example of calculation of the second upper limit output of battery unit 20. In FIG. FIG. 8 is a diagram showing a plurality of groups including one or more battery packs 10 out of the plurality of battery packs 10. As shown in FIG.

Referring to FIG. 8, when the number of battery packs 10 is three, the number of groups including one or more battery packs 10 is seven. FIG. 8 shows these seven groups 80i, 80j, 80k, 80l, 80m, 80n, 80o. The processor 31 calculates the upper limit output of each of the multiple groups 80i, 80j, 80k, 80l, 80m, 80n, 80o. The upper limit output of a group is the upper limit of power that the group can output. In the following description, the upper limit output of a group is expressed as "third upper limit output".

The processor 31 receives the detected voltage value and the upper limit current value from the BMS 12 of each battery pack 10 . FIG. 6 shows an example of the voltages and upper limit currents of the battery packs 10a, 10b, 10c. The first upper limit output of each battery pack 10 is obtained by multiplying the voltage and the upper limit current.

Referring to FIG. 5, processor 31 identifies battery packs 10 belonging to one of the plurality of groups (step S20). For example, the battery packs belonging to group 80i are identified as battery packs 10a, 10b, and 10c.

Processor 31 identifies the battery pack with the lowest voltage among battery packs 10a, 10b, and 10c belonging to group 80i (step S21). In the example shown in FIG. 6, the battery pack 10a is specified as the battery pack with the lowest voltage. The processor 31 sets the voltage 21.0 (V) of the battery pack 10a, which has the lowest voltage, as the reference voltage.

Processor 31 calculates the ratio between the voltage of each of the other battery packs 10b and 10c belonging to group 80i and the reference voltage. In the example shown in FIG. 6, the voltage ratio of the battery pack 10b is 0.84, and the voltage ratio of the battery pack 10c is 0.71.

Processor 31 calculates a duty ratio (DT ratio) to be applied to PWM control of each of battery packs 10a, 10b, and 10c (step S22). The duty ratio is obtained by squaring the voltage ratio.

Processor 31 calculates the first upper limit output of each of battery packs 10a, 10b, and 10c when the calculated duty ratio is applied (step S23). In the example shown in FIG. 6, the first upper limit output of the battery pack 10a is 210 (W), the first upper limit output of the battery pack 10b is 266 (W), and the first upper limit output of the battery pack 10c is 300 (W). .

The processor 31 adds up the first upper limit outputs when these duty ratios are applied to obtain the third upper limit output of the group (step S24). In the example shown in FIG. 6, 776 (W) is acquired as the third upper limit output of the group 80i.

In step S25, the processor 31 determines whether the third upper limit outputs of all groups have been calculated. If the calculation of the third upper limit output for all groups has not been completed, the process returns to step S20, and the groups for which the calculation has not yet been performed are processed.

In the example shown in FIG. 6, the processor 31 identifies the battery pack 10b with the lowest voltage among the battery packs 10b and 10c belonging to the group 80j. The processor 31 sets the voltage 25.0 (V) of the battery pack 10b, which has the lowest voltage, as the reference voltage. Then, the same processing as described above is performed, and 798 (W) is acquired as the third upper limit output of the group 80j.

The processor 31 also identifies the battery pack 10a with the lowest voltage among the battery packs 10a and 10c belonging to the group 80k. The processor 31 sets the voltage 21.0 (V) of the battery pack 10a, which has the lowest voltage, as the reference voltage. Then, the same processing as described above is performed to obtain 510 (W) as the third upper limit output of the group 80k. Similarly, processor 31 computes a third upper limit output for group 80l. In FIG. 6, an example of calculation of the third upper limit output of the group 80l is omitted. When one battery pack 10 belongs to a group like groups 80m, 80n and 80o shown in FIG. 8, the third upper limit output of the group is the first upper limit output of the battery packs 10 belonging to the group becomes.

When the calculation of the third upper limit output for all groups is completed, the process proceeds to step S26 (FIG. 5). In step S26, the processor 31 selects the maximum third upper limit output among the third upper limit outputs of all the groups. Processor 31 sets the selected third upper limit output as the second upper limit output of battery unit 20 . In the example shown in FIG. 6, the third upper limit output 798 (W) of group 80j is the maximum value. Processor 31 sets the 798 (W) as the second upper limit output of battery unit 20 .

FIG. 7 shows another example of calculation of the second upper limit output of the battery unit 20. In FIG. The states of the battery packs 10a, 10b, and 10c shown in FIG. 7 are different from those in FIG. The same processing as described above is performed for the battery packs 10a, 10b, and 10c in the state shown in FIG. The processor 31 selects the maximum third upper limit output among the third upper limit outputs of all the groups. In the example shown in FIG. 7, the third upper limit output 705 (W) of group 80i is the maximum value. Processor 31 sets 705 (W) as the second upper limit output of battery unit 20 .

Referring to FIG. 4, processor 31 controls discharging of each battery pack 10 based on the calculated second upper limit output of battery unit 20 (step S12). When the third upper limit output 798 (W) of group 80j shown in FIG. 6 is set as the second upper limit output of battery unit 20, battery unit 20 is composed of battery packs 10b and 10c belonging to group 80j. Processor 31 discharges battery packs 10b and 10c forming battery unit 20 .

Processor 31 sets the voltage 25.0 (V) of battery pack 10b, which has the lowest voltage among battery packs 10b and 10c, as the reference voltage. The processor 31 adjusts the voltage 29.4 (V) output from the other battery pack 10c to the reference voltage 25.0 (V) by PWM control. By adjusting the voltages output from the battery packs 10b and 10c belonging to the group 80j selected for discharge to be the same, the battery packs 10b and 10c belonging to the group 80j are connected in parallel for discharging. can be made

When the third upper limit output 705 (W) of the group 80i shown in FIG. 7 is set as the second upper limit output of the battery unit 20, the battery unit 20 is composed of the battery packs 10a, 10b, and 10c belonging to the group 80i. The processor 31 discharges the battery packs 10 a , 10 b , 10 c that constitute the battery unit 20 .

The processor 31 sets the voltage 21.0 (V) of the battery pack 10a, which has the lowest voltage among the battery packs 10a, 10b, and 10c, as the reference voltage. The processor 31 adjusts the voltages output from the other battery packs 10b and 10c to the reference voltage of 21.0 (V) by PWM control. By adjusting the voltages output from the battery packs 10a, 10b, and 10c belonging to the group 80i selected for discharge to be the same, the battery packs 10a, 10b, and 10c belonging to the group 80i are connected in parallel. It can be connected and discharged.

The power output by the battery control system 1 is supplied to the load 71 . When the load 71 stops operating and the discharge ends, the processor 31 ends the discharge control (step S13).

As described above, in the battery control system 1 of the present embodiment, the second upper limit output of the battery unit 20 is calculated using the first upper limit output of the plurality of battery packs 10, and the calculated second upper limit of the battery unit 20 Control discharge of the plurality of battery packs 10 based on the output.

In this embodiment, at least one of the plurality of battery packs 10 connected to the battery control system 1 may have specifications different from those of the other battery packs 10 . A plurality of battery packs 10 may have different specifications.

Regardless of whether the specifications of the plurality of battery packs 10 are the same or different, the upper limit output can be obtained for each battery pack 10, and the discharge of the combination of the plurality of battery packs 10 is controlled based on this upper limit output. . Even if the specifications of the plurality of battery packs 10 differ from each other, the upper limit output is a common physical quantity among the battery packs 10 . Therefore, by evaluating each battery pack 10 using the upper limit output, the battery packs 10 can be combined even if the specifications of the plurality of battery packs 10 are different from each other. Thereby, the degree of freedom in selecting the battery pack 10 can be improved.

Also, depending on the states of the plurality of battery packs 10, the third upper limit output does not necessarily increase as the number of combined battery packs 10 increases. For example, in the state of the battery packs 10a, 10b, and 10c shown in FIG. 6, the third upper limit output is maximum when the two battery packs 10b and 10c are combined. A third upper limit output is calculated for each of a plurality of groups in which the combination of battery packs 10 is different from each other, and the maximum third upper limit output among them is set as the second upper limit output of the battery unit 20 . By adopting the maximum third upper limit output obtained from the combination of the plurality of battery packs 10, it is possible to perform discharge that maximizes the capabilities of the plurality of battery packs 10. FIG.

Next, a process of changing the group to be discharged when the magnitude relationship of the third upper limit output among the plurality of groups is changed will be described.

For example, the states of the battery packs 10a, 10b, and 10c at the start of discharging are the states shown in FIG. 6, and the battery packs 10b and 10c belonging to the group 80j are to be discharged. It is assumed that the voltages of battery packs 10b and 10c gradually drop in the process of continuing discharging, resulting in the state shown in FIG. In the state shown in FIG. 7, the third upper limit output 705 (W) of the group 80i is larger than the third upper limit output 595 (W) of the group 80j. In this case, the group to be discharged may be changed from the group 80j to the group 80i.

FIG. 9 is a flow chart showing the process of changing the group to be discharged when the magnitude relationship of the third upper limit outputs among a plurality of groups changes.

The processor 31 periodically calculates the third upper limit output of each of the plurality of groups while discharging the battery pack 10 that constitutes the battery unit 20 (step S30). The calculation method of the third upper limit output is as described above.

The processor 31 determines whether or not the magnitude relationship of the third upper limit outputs among the groups has changed (step S31). For example, when the battery packs 10a, 10b, and 10c change from the state shown in FIG. 6 to the state shown in FIG. 7, the magnitude relationship of the third upper limit outputs among the groups changes.

When determining that the magnitude relationship of the third upper limit output has not changed, the processor 31 periodically repeats the calculation of the third upper limit output for each of the plurality of groups.

When determining that the magnitude relationship of the third upper limit output has changed, the processor 31 specifies a group having a larger third upper limit output than the power (power consumption) required by the load (step S32). Regarding the power consumption of the load, the processor 31 may receive information on power consumption from the load (external device), or may be estimated from the voltage and current output from the battery control system 1 . For example, when battery packs 10a, 10b, and 10c are in the state shown in FIG. 7 and the power consumption of the load is 500 (W), processor 31 identifies groups 80i and 80j.

Processor 31 selects a group to be discharged from groups 80i and 80j (step S33). For example, when priority is given to discharging with a surplus, the group 80i having the largest third upper limit output is selected as the group to be discharged. That is, the group to be discharged is changed from the group 80j to the group 80i. For example, when priority is given to suppressing deterioration of the battery pack 10a by limiting the discharging of the battery pack 10a, the discharging of the group 80j is maintained.

When the magnitude relationship of the third upper limit output changes, the group to be discharged may always be changed to the group with the largest third upper limit output. As a result, it is possible to perform discharge that makes the most of the capabilities of the plurality of battery packs 10 .

When discharging is to be terminated, for example, the load 71 stops operating, the processor 31 terminates discharging control (step S34).

Next, the process of changing the group to be discharged according to the magnitude relationship between the second upper limit output of the battery unit 20 and the power consumption of the load 71 will be described.

FIG. 10 is a flow chart showing the process of changing the group to be discharged according to the magnitude relationship between the second upper limit output of the battery unit 20 and the power consumption of the load 71 .

Processor 31 determines whether the second upper limit output of battery unit 20 is greater than the power consumption of load 71 (step S40). When determining that the second upper limit output is larger than the power consumption, the processor 31 determines whether the group to be discharged can be changed to a group with a smaller third upper limit output (step S41).

For example, assume that the battery packs 10a, 10b, and 10c are in the state shown in FIG. 7, and the group 80i is being selected as the group to be discharged. When the power consumption of the load is 500 (W), even if the group 80j is selected, it is possible to respond to the request from the load. In this case, processor 31 changes the group to be discharged from group 80i to group 80j (step S43).

Changing from group 80i to group 80j is synonymous with limiting discharge of battery packs 10a included in group 80i. Even if discharge of at least one of the battery packs 10 included in the group with the highest third upper limit output is restricted, the second upper limit output of the battery unit 20 is greater than the power consumption of the load 71. If so, the processor 31 may perform control to limit discharge of at least one battery pack 10 . As a result, deterioration of the battery pack 10 that limits its discharge can be suppressed.

Note that if priority is given to discharge with a margin, the selection of the group 80i having the highest third upper limit output may be maintained in step S43.

When discharging is to be terminated, for example, the load 71 stops operating, the processor 31 terminates discharging control (step S44).

When determining in step S40 that the second upper limit output of the battery unit 20 is equal to or less than the power consumption of the load 71, the processor 31 determines whether there is a group in which the third upper limit output is greater than the power consumption. If it is determined that there is, the processor 31 changes the group to be discharged to a group whose third upper limit output is larger than the power consumption (step S43). If it is determined that there is no group in which the third upper limit output is greater than the power consumption, the discharge control is terminated.

In the process shown in FIG. 10, when there are two or more groups with the third upper limit output greater than the power consumption of the load 71, a group other than the group with the largest third upper limit output can be selected. In the above example, the third upper limit outputs of groups 80 i and 80 j are greater than the power consumption of load 71 . In this case, processor 31 may select group 80j other than group 80i with the largest third upper limit output. By selecting a group in which one or more of the plurality of battery packs 10 are not used, deterioration of the unused battery packs 10 can be suppressed.

When selecting a group to be discharged from among a plurality of groups, a group that does not include the battery pack 10 with the smallest first upper limit output among the plurality of battery packs 10 may be selected. It is conceivable that the battery pack 10 with a small first upper limit output has a small remaining capacity or is advanced in deterioration. By not using the battery pack 10 with a small first upper limit output for discharging, stable discharging can be performed. Also, for the battery pack 10 with a small remaining capacity, it is possible to give priority to charging over discharging. Moreover, deterioration of the unused battery pack 10 can be suppressed.

When selecting a group to discharge from among a plurality of groups, a group 80 that does not include the battery pack 10 having the maximum first upper limit output among the plurality of battery packs 10 may be selected. It is conceivable that the battery pack 10 with a large first upper limit output has a large remaining capacity or is not degraded. For example, when the battery control system 1 is used as a charging station for an electric vehicle, it is desirable that the remaining capacity of the battery pack 10 to be replaced with the empty battery pack 10 mounted on the electric vehicle is large. Moreover, it is desirable that the battery pack 10 in which deterioration has not progressed is mounted on the electric vehicle. By not using the battery pack 10 with a large first upper limit output for discharging in the battery control system 1, the battery pack 10 can be mounted on the electric vehicle. Further, even when the battery pack 10 having a large upper limit output is removed from the battery control system 1 in order to be mounted on the electric vehicle, the discharging operation of the battery control system 1 can be continued.

As described with reference to FIG. 3 , multiple battery packs 10 are connected to converter 41 and inverter 42 via diodes 61 , 62 , 63 . The battery packs 10 included in the group selected for discharge are discharged while connected in parallel. For example, if group 80j is selected, battery packs 10b and 10c discharge while being connected in parallel with each other. At this time, the positive terminals of the battery packs 10a not included in the group 80j are connected to the parallel-connected node 68 via the diode 61. FIG. The switching element 51 is turned on. Since the voltage of battery pack 10a is lower than the reference voltage of group 80j, no current flows from battery pack 10a.

If the power consumption of the load 71 suddenly increases during discharging, the output voltage of the battery control system 1 may drop rapidly. When the voltage of node 68 becomes lower than the voltage of battery pack 10a, current flows through diode 61, and power is supplied to load 71 also from battery pack 10a. By connecting the non-selected battery packs 10 to the parallel-connected node 68 via diodes in this way, the battery control system 1 can be prevented from going down even when the power consumption of the load 71 suddenly increases. can be suppressed.

In the above description, the voltage of the battery pack 10 with the lowest voltage among the battery packs 10 included in the group is set as the reference voltage, but the present invention is not limited to this. The voltage of the battery packs 10 other than the battery pack 10 with the lowest voltage may be set as the reference voltage. In this case, the voltages of the battery packs 10 whose voltage is lower than the reference voltage are boosted so that the voltages output from the battery packs 10 included in the same group are adjusted to have the same magnitude. good too.

Exemplary embodiments of the present invention have been described above.

A battery control system 1 according to an embodiment of the present invention includes a plurality of connection devices 3 to which a plurality of battery packs 10 are connected, and a control device 30 that controls operations of the plurality of battery packs 10 . The control device 30 acquires the first upper limit output of each of the plurality of battery packs 10, and uses the first upper limit output of the plurality of battery packs 10 to obtain the second upper limit output of the battery unit 20 including the plurality of battery packs 10. The operation of the plurality of battery packs 10 is controlled based on the calculated second upper limit output of the battery unit 20 .

In the embodiment of the present invention, the second upper limit output of the battery unit 20 is calculated using the first upper limit output of the plurality of battery packs 10, and the plurality of battery packs are calculated based on the calculated second upper limit output of the battery unit 20. control 10.

Regardless of whether the specifications of the plurality of battery packs 10 are the same or different, the upper limit output can be obtained for each battery pack 10, and the discharge of the combination of the plurality of battery packs 10 is controlled based on this upper limit output. . Even if the specifications of the plurality of battery packs 10 differ from each other, the upper limit output is a common physical quantity among the battery packs 10 . Therefore, by evaluating each battery pack 10 using the upper limit output, the battery packs 10 can be combined even if the specifications of the plurality of battery packs 10 are different from each other. Thereby, the degree of freedom in selecting the battery pack 10 can be improved.

In one embodiment, the second upper limit output of the battery unit 20 is larger than the power consumption of the load 71 connected to the battery control system 1 even if the discharging of at least one of the plurality of battery packs 10 is restricted. In this case, control device 30 may perform control to limit discharge of at least one battery pack 10 .

Even if the discharge of at least one battery pack 10 is limited, if an upper limit output larger than the power consumption of the load 71 is obtained, by limiting the discharge of the at least one battery pack 10, the plurality of battery packs 10 can be used efficiently. For example, deterioration of the battery pack 10 that limits its discharge can be suppressed.

In one embodiment, the plurality of battery packs 10 are three or more battery packs 10, and the control device 30 selects the third group 80 of each of the plurality of groups 80 obtained by combining two or more of the plurality of battery packs 10. The upper limit output may be calculated, and the third upper limit output that is the largest among the third upper limit outputs of the plurality of groups 80 may be set as the second upper limit output of the battery unit 20 .

Depending on the state of the plurality of battery packs 10, the upper limit output does not always increase as the number of combined battery packs 10 increases. The third upper limit output of each of the plurality of groups 80 in which the battery packs 10 are combined differently is calculated, and the maximum upper limit output among them is set as the second upper limit output of the battery unit 20 . By adopting the maximum upper-limit output obtained from the combination of the plurality of battery packs 10, it is possible to perform discharge that maximizes the capabilities of the plurality of battery packs 10. FIG.

In one embodiment, the first group, which is one of the plurality of groups 80, includes the first battery pack 10a, and the controller 30 controls the battery pack 10 having the lowest voltage among the battery packs 10 included in the first group. When the battery pack 10 is the first battery pack 10a, the voltage of the first battery pack 10a is set as the reference voltage, and the ratio of each of the voltages of the other battery packs 10 included in the first group to the reference voltage is calculated. Calculate the duty ratio to be applied to each of the other battery packs 10 based on the calculated ratio, calculate the first upper limit output of each of the other battery packs 10 when the calculated duty ratio is applied, A value obtained by adding the calculated first upper limit output of the other battery pack 10 and the first upper limit output of the first battery pack 10a may be obtained as the third upper limit output of the first group.

The voltage output from each of the battery packs 10 included in the first group can be adjusted to have the same magnitude, and the battery packs 10 included in the first group can be connected in parallel and discharged. Also, the third upper limit output of the first group can be obtained in the form of discharging the battery packs 10 included in the first group by connecting them in parallel.

By performing the above calculation for each of the plurality of groups 80, the third upper limit output of each of the plurality of groups 80 can be obtained.

In one embodiment, even if the discharge of at least one battery pack 10 among the battery packs 10 included in the group having the maximum third upper limit output among the plurality of groups 80 is restricted, the battery control system 1 is connected to the battery pack 10. When the second upper limit output of the battery unit 20 is larger than the power consumption of the load 71 to be discharged, the control device 30 may perform control to limit discharge of at least one battery pack 10 .

Even if the discharge of at least one battery pack 10 is limited, if an upper limit output larger than the power consumption of the load 71 is obtained, by limiting the discharge of the at least one battery pack 10, the plurality of battery packs 10 can be used efficiently. For example, deterioration of the battery pack 10 that limits its discharge can be suppressed.

In one embodiment, the control device 30 selects one group having a third upper limit output greater than the power consumption of the load 71 connected to the battery control system 1 from among the plurality of groups 80, and assigns the selected group Control may be performed to discharge the included battery pack 10 . Thereby, the required power can be supplied to the load 71 .

In one embodiment, if there are two or more groups among the plurality of groups 80 in which the third upper limit output is greater than the power consumption of the load 71 connected to the battery control system 1, the control device 30 Among the groups 80, one group other than the group having the maximum third upper limit output is selected, and control is performed to discharge the battery packs 10 included in the selected group. good too.

A plurality of battery packs 10 can be used efficiently by selecting a group other than the group that maximizes the third upper limit output. For example, by selecting a group in which one or more of the plurality of battery packs 10 are not used, deterioration of the unused battery packs 10 can be suppressed.

In one embodiment, when selecting one group from the plurality of groups 80, the control device 30 selects a group that does not include the battery pack 10 with the smallest first upper limit output among the plurality of battery packs 10. and discharge the battery packs 10 included in the selected group.

It is conceivable that the battery pack 10 with a small first upper limit output has a small remaining capacity or is advanced in deterioration. By not using the battery pack 10 with a small first upper limit output for discharging, stable discharging can be performed. Also, for the battery pack 10 with a small remaining capacity, it is possible to give priority to charging over discharging. Moreover, deterioration of the unused battery pack 10 can be suppressed.

In one embodiment, when selecting one group from the plurality of groups 80, the control device 30 selects a group that does not include the battery pack 10 having the maximum first upper limit output among the plurality of battery packs 10. and discharge the battery packs 10 included in the selected group.

It is conceivable that the battery pack 10 with a large first upper limit output has a large remaining capacity or is not degraded. When the battery control system 1 is used, for example, as a charging station for an electric vehicle, it is desirable that the remaining capacity of the battery pack 10 to be replaced with the empty battery pack 10 mounted on the electric vehicle is large. Moreover, it is desirable that the battery pack 10 in which deterioration has not progressed is mounted on the electric vehicle.

By not using the battery pack 10 with a large first upper limit output for discharging in the battery control system 1, the battery pack 10 can be mounted on the electric vehicle. Further, even when the battery pack 10 having a large upper limit output is removed from the battery control system 1 in order to be mounted on the electric vehicle, the discharging operation of the battery control system 1 can be continued.

In one embodiment, when discharging the battery packs 10 included in a group selected from among the plurality of groups 80, the control device 30 selects the battery pack 10 having the lowest voltage among the battery packs 10 included in the selected group. may be set as the reference voltage, and the voltages output from the other battery packs 10 included in the selected group may be adjusted to the reference voltage.

By adjusting the voltage output from each of the battery packs 10 included in the group selected for discharging to the same magnitude, the battery packs 10 included in the group can be connected in parallel and discharged.

In one embodiment, the control device 30 may adjust each of the voltages output from the other battery packs 10 to the reference voltage by PWM (Pulse Width Modulation) control. By PWM control, the voltages output from each of the battery packs 10 can be adjusted to have the same magnitude.

In one embodiment, the battery packs 10 included in the selected group 80 are discharged while being connected in parallel, and among the battery packs 10 not included in the selected group 80, the output voltage is lower than the reference voltage. The positive terminal of 10 may be connected through diodes 61, 62 or 63 to node 68 of the parallel connection.

If the magnitude of the load 71 changes suddenly, the output voltage of the battery control system 1 may drop suddenly. When the output voltage of the battery control system 1 becomes lower than the output voltage of the non-selected battery pack 10 connected via the diode 61, 62 or 63, the non-selected battery pack 10 also supplies power to the load 71. will be This can prevent the battery control system 1 from going down.

In one embodiment, in the process of discharging the battery packs 10 included in the selected group 80, if the magnitude relationship between the third upper limit outputs of the plurality of groups 80 changes, the control device 30 changes the group to be discharged. good too.

As the remaining capacity of the battery pack 10 decreases due to discharging, the magnitude relationship between the third upper limit outputs of the groups 80 changes. In this case, by changing the group 80 to be discharged, it is possible to discharge in a more appropriate group 80 .

In one embodiment, the control device 30 calculates the first upper limit output of the battery pack 10 based on the detected voltage value of the battery pack 10 and the upper limit current of the battery pack 10 corresponding to the detected voltage value. good too. Using the calculated first upper limit output of the battery pack 10, the second upper limit output of the battery unit 20 including the plurality of battery packs 10 can be calculated.

In one embodiment, at least one of the plurality of battery packs 10 may have specifications different from those of the other battery packs 10 .

By combining battery packs 10 using the upper limit output, battery packs 10 with different specifications can be combined. Thereby, the degree of freedom in selecting the battery pack 10 can be improved.

A computer program according to an embodiment of the present invention causes a computer to control operations of the plurality of battery packs 10 . The computer program obtains a first upper limit output of each of the plurality of battery packs 10, and uses the first upper limit output of the plurality of battery packs 10 to obtain a second upper limit output of the battery unit 20 including the plurality of battery packs 10. The computer is caused to perform the calculation and control the operation of the plurality of battery packs 10 based on the calculated second upper limit output of the battery unit 20 .

INDUSTRIAL APPLICABILITY The present invention is particularly useful in the technical field of combining and discharging a plurality of battery packs.

1: battery control system, 2: housing, 3: connector (connection device), 4: charging connector, 5: discharging connector, 6: discharging connector, 10: battery pack, 11: cell (single battery), 12: Battery Management System (BMS), 13: Connector, 20: Battery Unit, 30: Control Device, 31: Processor, 32: Memory, 33: Communication Circuit, 41: Converter, 42: Inverter, 43: Charger, 51 , 52, 53: PWM switching element, 54: discharging switching element, 55: charging switching element, 61, 62, 63, 64, 65, 66: diode, 68: node, 71: load (external device), 73: power generator, 80: group

Claims (14)

a plurality of connection devices to which a plurality of battery packs are connected;
a control device that controls the operation of the plurality of battery packs;
A battery control system comprising:
The control device is
obtaining a first upper limit output of each of the plurality of battery packs;
calculating a second upper limit output of a battery unit including the plurality of battery packs using the first upper limit output of the plurality of battery packs;
controlling the operation of the plurality of battery packs based on the calculated second upper limit output of the battery unit ;
The plurality of battery packs are three or more battery packs,
The control device is
calculating a third upper limit output for each of a plurality of groups obtained by combining two or more of the plurality of battery packs;
setting a third upper limit output that is the largest among the third upper limit outputs of the plurality of groups as the second upper limit output of the battery unit;
a first group, one of the plurality of groups, including a first battery pack;
The control device is
if the battery pack having the lowest voltage among the battery packs included in the first group is the first battery pack, setting the voltage of the first battery pack to a reference voltage;
calculating a ratio between each of the voltages of the other battery packs included in the first group and the reference voltage;
calculating a duty ratio to be applied to each of the other battery packs based on the calculated ratio;
calculating a first upper limit output of each of the other battery packs when the calculated duty ratio is applied;
The battery control system , wherein a value obtained by adding the calculated first upper limit output of the other battery pack and the first upper limit output of the first battery pack is obtained as the third upper limit output of the first group . When the second upper limit output of the battery unit is larger than the power consumption of the load connected to the battery control system even if discharge of at least one of the plurality of battery packs is restricted, the control device 2. The battery control system according to claim 1, which controls discharge of said at least one battery pack. Power consumption of the load connected to the battery control system even if discharge of at least one of the battery packs included in the group having the maximum third upper limit output among the plurality of groups is restricted. 2. The battery control system according to claim 1 , wherein when the second upper limit output of said battery unit is greater than the second upper limit output of said battery unit, said control device performs control to limit discharge of said at least one battery pack. The control device is
selecting from among the plurality of groups one group in which the third upper limit output is greater than the power consumption of the load connected to the battery control system;
4. The battery control system according to any one of claims 1 to 3 , which controls discharging of the battery packs included in the selected group. When there are two or more groups among the plurality of groups in which the third upper limit output is greater than the power consumption of the load connected to the battery control system, the control device
selecting one group having the third upper limit output greater than the power consumption, other than the group having the maximum third upper limit output, from among the plurality of groups;
5. The battery control system according to any one of claims 1 to 4 , which controls discharging of the battery packs included in the selected group. When selecting one group from the plurality of groups, the control device selects a group that does not include the battery pack having the smallest first upper limit output among the plurality of battery packs,
6. The battery control system according to claim 1 , which controls discharging of the battery packs included in the selected group. When selecting one group from the plurality of groups, the control device selects a group that does not include the battery pack having the maximum first upper limit output among the plurality of battery packs,
6. The battery control system according to claim 1 , which controls discharging of the battery packs included in the selected group. When discharging battery packs included in a group selected from the plurality of groups,
The control device is
setting the voltage of the battery pack having the lowest voltage among the battery packs included in the selected group as a reference voltage;
8. The battery control system according to any one of claims 1 to 7 , wherein control is performed to adjust voltages output from other battery packs included in the selected group to the reference voltage. 9. The battery control system according to claim 8 , wherein said controller adjusts each of the voltages output from said other battery packs to said reference voltage by PWM (Pulse Width Modulation) control. a plurality of connection devices to which a plurality of battery packs are connected;
a control device that controls the operation of the plurality of battery packs;
A battery control system comprising:
The control device is
obtaining a first upper limit output of each of the plurality of battery packs;
calculating a second upper limit output of a battery unit including the plurality of battery packs using the first upper limit output of the plurality of battery packs;
controlling the operation of the plurality of battery packs based on the calculated second upper limit output of the battery unit;
The plurality of battery packs are three or more battery packs,
The control device is
calculating a third upper limit output for each of a plurality of groups obtained by combining two or more of the plurality of battery packs;
setting a third upper limit output that is the largest among the third upper limit outputs of the plurality of groups as the second upper limit output of the battery unit;
When discharging battery packs included in a group selected from the plurality of groups,
The control device is
setting the voltage of the battery pack having the lowest voltage among the battery packs included in the selected group as a reference voltage;
controlling each of the voltages output from the other battery packs included in the selected group to be adjusted to the reference voltage;
the battery packs included in the selected group are connected in parallel and discharged;
A battery control system according to claim 1 , wherein a positive terminal of a battery pack having an output voltage lower than the reference voltage among the battery packs not included in the selected group is connected to the parallel-connected node via a diode. 11. The control device changes the group to be discharged when the magnitude relationship of the third upper limit outputs of the plurality of groups changes in the process of discharging the battery packs included in the selected group. A battery control system according to any one of the preceding claims. 2. From claim 1, wherein the control device calculates a first upper limit output of the battery pack based on a detected voltage value of the battery pack and an upper limit current of the battery pack corresponding to the detected voltage value. 12. The battery control system according to any one of 11 . 13. The battery control system according to any one of claims 1 to 12 , wherein at least one of said plurality of battery packs has specifications different from other battery packs. A computer program that causes a computer to control the operation of a plurality of battery packs,
Said computer program comprises:
obtaining a first upper limit output of each of the plurality of battery packs;
calculating a second upper limit output of a battery unit including the plurality of battery packs using the first upper limit output of the plurality of battery packs;
causing the computer to control the operation of the plurality of battery packs based on the calculated second upper limit output of the battery unit ;
The plurality of battery packs are three or more battery packs,
Said computer program comprises:
calculating a third upper limit output for each of a plurality of groups obtained by combining two or more of the plurality of battery packs;
setting a third upper limit output, which is the largest among the third upper limit outputs of the plurality of groups, as the second upper limit output of the battery unit;
causing said computer to execute
a first group, one of the plurality of groups, including a first battery pack;
Said computer program comprises:
setting the voltage of the first battery pack to a reference voltage when the battery pack having the lowest voltage among the battery packs included in the first group is the first battery pack;
calculating a ratio between each of the voltages of the other battery packs included in the first group and the reference voltage;
calculating a duty ratio to be applied to each of the other battery packs based on the calculated ratio;
calculating a first upper limit output of each of the other battery packs when the calculated duty ratio is applied;
Acquiring a value obtained by adding the calculated first upper limit output of the other battery pack and the first upper limit output of the first battery pack as the third upper limit output of the first group.
a computer program that causes the computer to execute

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