Storage battery system

Abstract

A storage battery system (10) comprises: a plurality of storage battery boards (13-1 to 13-N); and a control device (12) that controls the plurality of storage battery boards (13-1 to 13-N). The storage battery board (13-i) is provided with a switch (SW) for controlling the connection between the storage battery board (13-i) and an uninterruptible power supply device (1). The control device (12) controls the switches (SW) of the plurality of storage battery boards (13-1 to 13-N) on the basis of the size of a load (6) connected to the uninterruptible power supply device (1) during a power failure in which the power supply from an AC input power supply (2) to the uninterruptible power supply device (1) is cut off.

Description

Battery storage system

[0001] The present disclosure relates to a battery storage system.

[0002] Conventionally, there has been known an uninterruptible power supply that normally supplies power from an AC power source to a load and, during a power outage, supplies power from a storage battery to the load (see, for example, Patent Document 1). The storage battery that consumed power during the power outage is normally charged with power from the AC power source.

[0003] Japanese Patent Application Laid-Open No. 2021-40398

[0004] If the power of the storage battery is discharged more than necessary during a power outage, it will take a long time to charge the storage battery under normal circumstances.

[0005] Therefore, an object of the present disclosure is to provide a storage battery system that can reduce the amount of discharge during a power outage.

[0006] The battery system of the present disclosure includes a plurality of battery panels and a control device that controls the plurality of battery panels. The battery panels include switches that control connections between the battery panels and power supply devices. In the event of a power outage in which power supply devices are cut off from other external power sources, the control device controls the switches of the plurality of battery panels based on the magnitude of the load connected to the power supply devices.

[0007] According to the present disclosure, the control device controls the switches of multiple battery panels based on the size of the load connected to the power supply device during a power outage, thereby reducing the amount of discharge during a power outage.

[0008] 1 is a diagram showing the configuration of a power supply system of a first embodiment. FIG. 2 is a diagram showing the configuration of a storage battery system 10. FIG. 3 is a functional block diagram of a control device 12E of a reference example. FIG. 4 is a functional block diagram of a control device 12 of the first embodiment. FIG. 5 is a diagram showing the relationship between a system discharge current Is and the number of inserted units L. FIG. 6 is a functional block diagram of a control device 12A of a second embodiment. FIG. 7 is a functional block diagram of a control device 12B of a third embodiment. FIG. 8 is a functional block diagram of a control device 12C of a fourth embodiment. FIG. 9 is a diagram showing the configuration of a power supply system of a fifth embodiment. FIG. 10 is a functional block diagram of a control device 12D of the fifth embodiment.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments will be described with reference to the accompanying drawings. First Embodiment Fig. 1 is a diagram showing the configuration of a power supply system according to a first embodiment.

[0010] The power supply system includes an AC input power supply 2, an uninterruptible power supply 1, a load 6, and a storage battery system 10.

[0011] The uninterruptible power supply 1 is connected to an AC input power supply 2, which is an external power supply, and a load 6. The AC input power supply 2 supplies AC power to the uninterruptible power supply 1. The AC input power supply 2 is configured by, for example, a commercial AC power supply or a private generator.

[0012] The uninterruptible power supply 1 includes a converter 3, an inverter 4, and a chopper circuit 5. The converter 3 and the inverter 4 are connected in series between an AC input power supply 2 and a load 6. The converter 3 converts the AC voltage supplied from the AC input power supply 2 into a DC voltage. The inverter 4 converts the DC voltage converted by the converter 3 into an AC voltage.

[0013] The chopper circuit 5 converts the voltage level of the DC voltage and supplies it to the storage battery system 10. The storage battery system 10 is connected to the converter 3 via the chopper circuit 5 in parallel with the inverter 4.

[0014] During normal operation when AC power is supplied from the AC input power source 2, the DC voltage generated by the converter 3 is stored in the battery system 10 via the chopper circuit 5, and is also converted to AC voltage by the inverter 4 and supplied to the load 6. On the other hand, during a power outage when the supply of AC voltage from the AC input power source 2 stops, the operation of the converter 3 is stopped. The DC voltage stored in the battery system 10 is sent to the inverter 4 via the chopper circuit 5, converted to AC voltage by the inverter 4 and supplied to the load 6. Therefore, according to the uninterruptible power supply 1, it is possible to continue operating the load 6 using the power stored in the battery system 10 even during a power outage.

[0015] 2 is a diagram showing the configuration of the battery system 10. The battery system 10 includes N battery panels 13-1 to 13-N and a battery monitoring panel 11. In the following description, the battery panels 13-1 to 13-N may be collectively referred to as the battery panel 13.

[0016] The battery panel 13-i (i = 1 to N) includes M cells CL-1 to CL-M, a current detector 51, a switch SW, and a BMU (Battery Management Unit) 53. In the following description, the cells CL-1 to CL-M may be represented as a cell CL.

[0017] When the switch SW is turned on, the battery panel 13-i is connected to the uninterruptible power supply 1. When the switch signal S(i) becomes high level, the switch SW is turned on (closed). When the switch signal S(i) becomes low level, the switch SW is turned on (opened).

[0018] When the switch SW is on, the current detector 51 detects the current (discharge current) Ii flowing from the battery panel 13-i to the uninterruptible power supply 1. The current detector 51 transmits the detected current Ii to the BMU 53.

[0019] The cell CL includes a lithium ion battery BT and a CMU (Cell Monitoring Unit) 52 .

[0020] The CMU 52 measures the voltage (cell voltage) Vc of the lithium ion battery BT and transmits it to the BMU 53 .

[0021] The BMU 53 detects a fault in the battery panel 13 based on the voltage Vc or the current Ii. The BMU 53 calculates the sum of the voltages Vc of the M lithium-ion batteries BT as the voltage Vi of the battery panel 13. The BMU 53 transmits the current Ii, the voltage Vi, and fault information Fi of the battery panel 13 to the control device 12 of the battery monitoring panel 11.

[0022] The battery monitoring panel 11 includes a control device 12. The control device 12 includes a CPU (Central Processing Unit) and a memory. The CPU controls the battery panels 13-1 to 13-N by executing a program stored in the memory.

[0023] The control device 12 receives the current Ii, the voltage Vi, and the fault information Fi from the BMUs 53 of the N battery panels 13-i. In the event of a power outage when the power supply from the AC input power source 2, which is an external power source, to the uninterruptible power supply 1 is cut off, the control device 12 controls the switches SW of the N battery panels 13-1 to 13-N based on the size of the load 6 connected to the uninterruptible power supply 1.

[0024] (Control Device of Reference Example) First, a control device 12E of the reference example will be described. Fig. 3 is a functional block diagram of the control device 12E of the reference example. The control device 12E includes a state detection circuit 21.

[0025] The status detection circuit 21 detects the status of the battery panel 13-i based on at least one of the voltage Vi, current Ii, and fault information Fi sent from the BMU 53 of the battery panel 13-i (i = 1 to N). For example, the status detection circuit 21 detects that the battery panel 13-i is abnormal when the difference between the voltage Vi sent from the BMU 53 of the battery panel 13-i and the average value of N voltages V1 to VN sent from the BMU 53 of the battery panels 13-1 to 13-N is equal to or greater than a threshold. Alternatively, the status detection circuit 21 detects that the battery panel 13-i is abnormal when the difference between the current Ii sent from the BMU 53 of the battery panel 13-i and the average value of N currents I1 to IN sent from the BMU 53 of the battery panels 13-1 to 13-N is equal to or greater than a threshold. Alternatively, the state detection circuit 21 detects that the battery panel 13-i is abnormal when the fault information Fi sent from the BMU 53 of the battery panel 13-i indicates a fault.

[0026] The state detection circuit 21 sets the switch signal S(i) of the battery panel 13-i in the normal state to a high level, and the state detection circuit 21 sets the switch signal S(i) of the battery panel 13-i in the abnormal state to a low level.

[0027] In the reference example, during a power outage, the switches of each battery panel remain on unless there is an abnormality in the battery panel, so the battery system discharges beyond its specified time even under light load, and as a result, it takes a long time to charge the battery system after power is restored.

[0028] (Control Device of First Embodiment) Next, the control device 12 of the first embodiment will be described. Fig. 4 is a functional block diagram of the control device 12 of the first embodiment. The control device 12 includes a state detection circuit 21, a states of charge (SOC) calculation circuit 22, an application possibility determination circuit 23, a system discharge current calculation circuit 24, a number of units to be inserted determination circuit 25, an adjustment command circuit 26, and a switch control circuit 27.

[0029] As in the reference example, the state detection circuit 21 detects the state of the battery panel 13-i based on at least one of the voltage Vi, current Ii, and fault information Fi sent from the BMU 53 of the battery panel 13-i (i = 1 to N). The state detection circuit 21 sets the power-on command signal STi of the battery panel 13-i in a normal state to a high level. The state detection circuit 21 sets the power-on command signal STi of the battery panel 13-i in an abnormal state to a low level.

[0030] The SOC calculation circuit 22 calculates the SOCi of the battery panel 13-i (i = 1 to N) based on the voltage Vi sent from the BMU 53 of the battery panel 13-i, etc. The SOC calculation circuit 22 may calculate the SOCi of the battery panel 13-i based on the average value of the voltages Vc of the M lithium ion batteries BT of the battery panel 13-i.

[0031] The input feasibility determination circuit 23 determines that the battery panel 13-i is inputtable when the fault information Fi of the battery panel 13-i indicates normal operation and the SOCi of the battery panel 13-i is equal to or greater than a threshold value. The input feasibility determination circuit 23 determines that the battery panel 13-i is not inputtable when the fault information Fi of the battery panel 13-i indicates a fault or the SOC-i of the battery panel 13-i is less than a threshold value. The input feasibility determination circuit 23 sets the input feasibility signal Xi of the battery panel 13-i that is inputtable to a high level. The input feasibility determination circuit 23 sets the input feasibility signal Xi of the battery panel 13-i that is not inputtable to a low level.

[0032] The system discharge current calculation circuit 24 calculates the sum of the currents I1 to IN sent from the BMUs 53 of the battery panels 13-1 to 13-N as the system discharge current Is. The magnitude of the system discharge current Is represents the magnitude of the load 6 connected to the uninterruptible power supply 1. The larger the system discharge current Is, the larger the load 6.

[0033] The number-of-battery-to-be-inserted determination circuit 25 determines the number L of battery panels to be inserted based on the system discharge current Is. The number-of-battery-to-be-inserted determination circuit 25 increases the number of battery panels to be inserted in a stepwise manner based on an increase in the system discharge current Is.

[0034] Fig. 5 is a diagram showing the relationship between the system discharge current Is and the number of inserted units L. As shown in Fig. 5, the number of inserted units increases by one every time the system discharge current Is increases by ΔI.

[0035] The adjustment command circuit 26 determines which battery panels 13 will remain powered on based on the number L of battery panels to be inserted and the power-on enable signals Xi (i = 1 to N) of the battery panels 13-i. The adjustment command circuit 26 calculates the total number R of battery panels 13 that can be inserted based on the power-on enable signals Xi (i = 1 to N). When the total number R of battery panels 13 that can be inserted is equal to or greater than the number L of battery panels to be inserted, the adjustment command circuit 26 determines L arbitrary battery panels 13 from the R battery panels 13 that can be inserted as battery panels that will remain powered on, and determines the remaining battery panels as battery panels that will not remain powered on. The adjustment command circuit 26 sets the adjustment command signal ATi of the battery panels 13-i that will remain powered on to a high level. The adjustment command circuit 26 sets the adjustment command signal ATi of the battery panels 13-i that will not remain powered on to a low level.

[0036] When the total number R of battery panels 13 that can be inserted is less than the number L of inserted battery panels, the adjustment command circuit 26 sets the adjustment command signals AT1 to ATN of the battery panels 13-1 to 13-N to a high level.

[0037] The switch control circuit 27 sets the switch signal S(i) to a high level when the closing command signal STi is at a high level and the adjustment command signal ATi is at a high level. The switch control circuit 27 sets the switch signal S(i) to a low level when the closing command signal STi is at a low level or the adjustment command signal ATi is at a low level.

[0038] As described above, according to this embodiment, the discharge time under light load can be adjusted to match the specified time by controlling the switching on of each battery panel. This reduces the discharge amount of the entire battery panel during a power outage, thereby shortening the charging time after power is restored.

[0039] 6 is a functional block diagram of a control device 12A according to a second embodiment. The control device 12A according to the second embodiment differs from the control device 12 according to the first embodiment in that the control device 12A according to the second embodiment includes a supply time counter 31 and an adjustment command circuit 26A instead of the adjustment command circuit 26.

[0040] The input time counter 31 counts the cumulative value Ti of the input time (the time the switch SW is on) of the battery panel 13-i during a power outage. For example, if there have been three power outages since the start of operation of the uninterruptible power supply 1 to the present, and the input time of the battery panel 13-1 during the first power outage was 10 minutes, the input time during the second power outage was 0 minutes, and the input time during the third power outage was 5 minutes, the input time of the battery panel 13-1 would be 15 minutes. For example, the input time counter 31 can count the cumulative value Ti of the input time (the time the switch SW is on) of the battery panel 13-i by counting the time during which the switch signal S(i) is at a high level during a power outage.

[0041] The adjustment command circuit 26A determines which storage battery panels 13 will remain powered on based on the number L of battery panels to be inserted, the power-on enable signals Xi (i = 1 to N) of the storage battery panels 13-i, and the cumulative power-on time Ti (i = 1 to N) of the storage battery panels 13-i. The adjustment command circuit 26A calculates the total number R of storage battery panels 13 that can be inserted based on the power-on enable signals Xi (i = 1 to N). When the total number R of storage battery panels 13 that can be inserted is equal to or greater than the number L of storage battery panels to be inserted, the adjustment command circuit 26 determines L storage battery panels 13 from the R storage battery panels 13 that can be inserted, in order from the one with the smallest cumulative power-on time T, as storage battery panels that will remain powered on, and determines the remaining storage battery panels as storage battery panels that will not remain powered on. The adjustment command circuit 26A sets the adjustment command signal ATi of the storage battery panels 13-i that will remain powered on to a high level. The adjustment command circuit 26A sets the adjustment command signal ATi of the battery panel 13-i that does not maintain the power supply to a low level.

[0042] When the total number R of battery panels 13 that can be inserted is less than the number L of inserted battery panels, the adjustment command circuit 26A sets the adjustment command signals AT1 to ATN of the battery panels 13-1 to 13-N to a high level.

[0043] As described above, according to this embodiment, power is supplied from a battery panel whose SOC is equal to or greater than the threshold value and whose cumulative value of the input time during a power outage is small, so that deterioration of the battery panels can be evened out. Note that the number of times the battery panel is input may be used instead of the cumulative value of the input time of the battery panel.

[0044] 7 is a functional block diagram of a control device 12B according to a third embodiment. The control device 12B according to the third embodiment differs from the control device 12A according to the second embodiment in that the control device 12B according to the third embodiment does not include the SOC calculation circuit 22 and includes an application possibility determination circuit 23B instead of the application possibility determination circuit 23.

[0045] The input feasibility determination circuit 23B determines that the battery panel 13-i is inputtable when the fault information Fi of the battery panel 13-i indicates normal operation. The input feasibility determination circuit 23B determines that the battery panel 13-i is not inputtable when the fault information Fi of the battery panel 13-i indicates a fault. The input feasibility determination circuit 23B sets the input feasibility signal Xi of the battery panel 13-i that is inputtable to a high level. The input feasibility determination circuit 23B sets the input feasibility signal Xi of the battery panel 13-i that is not inputtable to a low level.

[0046] As described above, according to this embodiment, power is supplied from the battery panel with the smallest cumulative input time, so that deterioration of the battery panels can be evened out.

[0047] 8 is a functional block diagram of a control device 12C according to a fourth embodiment. The control device 12C according to the fourth embodiment differs from the control device 12 according to the first embodiment in that the control device 12C according to the fourth embodiment does not include the state detection circuit 21 and the adjustment command circuit 26, and includes a switch control circuit 27C instead of the switch control circuit 27.

[0048] The switch control circuit 27C determines which battery panels 13 will remain powered on based on the number L of battery panels to be inserted and the power-on enable signals Xi (i = 1 to N) of the battery panels 13-i. The switch control circuit 27C calculates the total number R of battery panels 13 that can be inserted based on the power-on enable signals Xi (i = 1 to N). When the total number R of battery panels 13 that can be inserted is equal to or greater than the number L of battery panels to be inserted, the switch control circuit 27C determines L battery panels 13 from the R battery panels 13 that can be inserted as battery panels that will remain powered on, and determines the remaining battery panels as battery panels that will not remain powered on. The switch control circuit 27C sets the switch signal S(i) of the battery panels 13-i that will remain powered on to a high level. The switch control circuit 27C sets the switch signal S(i) of the battery panels 13-i that will not remain powered on to a low level.

[0049] When the total number R of battery panels 13 that can be plugged in is less than the number L of battery panels that can be plugged in, the switch control circuit 27C sets the switch signals S(1) to S(N) of the battery panels 13-1 to 13-N to a high level.

[0050] As described above, the battery system of this embodiment differs from the first to third embodiments in that it cannot prevent the application of power to an abnormal battery panel based on the detection result of the status detection circuit 21. However, like the first to third embodiments, the battery system of this embodiment can prevent the application of power to a faulty battery panel based on the application permission determination circuit 23. If it is sufficient to determine the fault state based on the application permission determination circuit 23, it is possible to avoid providing the status detection circuit 21 in the control device, as in this embodiment.

[0051] In this embodiment, similarly to the third embodiment, the power-on / power-on determination circuit 23B may be used instead of the power-on / power-on determination circuit 23.

[0052] 9 is a diagram showing the configuration of a power supply system according to a fifth embodiment. This power supply system includes an ammeter 41 provided in the wiring between the uninterruptible power supply 1 and the load 6.

[0053] The ammeter 41 detects the magnitude of the load current IL flowing from the uninterruptible power supply 1 to the load 6. The magnitude of the load current IL represents the magnitude of the load 6. The larger the load current IL, the larger the load 6.

[0054] 10 is a functional block diagram of a control device 12D according to the fifth embodiment. The control device 12D according to the fifth embodiment differs from the control device 12 according to the first embodiment in that the control device 12D according to the fifth embodiment does not include the system discharge current calculation circuit 24 and includes a number-of-units-to-be-inserted determination circuit 25D instead of the number-of-units-to-be-inserted determination circuit 25.

[0055] The number-of-units-to-be-inserted determination circuit 25D determines the number L of battery panels to be inserted based on the load current IL. The number-of-units-to-be-inserted determination circuit 25D may increase the number of battery panels to be inserted in a stepwise manner based on an increase in the load current IL.

[0056] As described above, according to this embodiment, the magnitude of the load 6 can be detected based on the load current IL instead of the system discharge current.

[0057] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0058] 1 uninterruptible power supply, 2 AC input power supply, 3 converter, 4 inverter, 5 chopper circuit, 6 load, 10 battery system, 11 battery monitoring panel, 12, 12A, 12B, 12C, 12D, 12E control device, 13 battery panel, 21 status detection circuit, 22 SOC calculation circuit, 23, 23B input possibility determination circuit, 24 system discharge current calculation circuit, 25, 25D input number determination circuit, 26, 26A adjustment command circuit, 27, 27C switch control circuit, 31 input time counter, 41 ammeter, 51 current detector, 52 CMU, 53 BMU, BT lithium ion battery, CL cell, SW switch.

Claims

1. A battery system comprising: a plurality of battery panels; and a control device that controls the plurality of battery panels, wherein the battery panels comprise switches that control connections between the battery panels and a power supply device; and wherein the control device controls the switches of the plurality of battery panels based on the magnitude of the load connected to the power supply device during a power outage when the power supply from another external power source to the power supply device is cut off.

2. The battery system according to claim 1, wherein the control device calculates the magnitude of the load connected to the power supply device as the sum of the magnitude of the current flowing from the plurality of battery panels to the power supply device.

3. The battery system according to claim 1, wherein the control device determines the number of battery panels to be connected to the power supply device during the power outage based on the magnitude of the load.

4. A battery system as described in claim 3, wherein the control device increases the number of battery panels connected to the power supply device in a stepwise manner during the power outage based on an increase in the magnitude of the load.

5. The battery system of claim 3, wherein the control device determines the battery panel to be connected to the power supply device during the power outage based on the SOC of the battery panel within the determined number of battery panels.

6. The battery system according to claim 5, wherein the control device connects battery panels whose SOC is equal to or greater than a threshold value to the power supply device within the determined number of battery panels.

7. A battery system as described in claim 3, wherein the control device determines the battery panel to be connected to the power supply device during a power outage based on the history of connections between the battery panel and the power supply device during past power outages, within the range of the determined number of battery panels.

8. A battery system as described in claim 7, wherein the control device determines the battery panel to be connected to the power supply device during a power outage based on the cumulative value of the connection time between the battery panel and the power supply device during past power outages, within the range of the determined number of battery panels.

9. The battery system according to claim 5, wherein the control device determines, from among battery panels in a normal state, a battery panel to be connected to the battery panel in the event of the power outage.

10. A storage battery system according to any one of claims 1 to 9, wherein the power supply is an uninterruptible power supply.

11. The battery system according to any one of claims 1 to 9, wherein the battery panel is equipped with lithium ion batteries.

Images