Charge and discharge test system, charge and discharge test method, and program

Abstract

Provided are a charge and discharge test system, a charge and discharge test method, and a program that make it possible to increase the proportion of a power sharing period to a test period. A charge and discharge test system 10 comprises a control device that controls a first bidirectional DC / DC converter 14 and a second bidirectional DC / DC converter 15 so that power is shared between a test battery 11 and a non-test battery 12 during a charge and discharge test, and controls operation of an AC / DC converter 13 according to power surplus or deficit on a direct-current bus 16. The control device executes: determination voltage acquisition processing for acquiring a determination voltage that is a voltage of the non-test battery 12; voltage determination processing for determining whether or not a forcing condition set for the determination voltage is satisfied; and forcing processing for performing, if the forcing condition is satisfied, forced discharging or forced charging of the non-test battery 12 by controlling the second bidirectional DC / DC converter 15 so that the forcing condition is not satisfied.

Description

Charge / discharge test system, charge / discharge test method, and program

[0001] The present disclosure relates to a charge / discharge test system, a charge / discharge test method, and a program for performing a charge / discharge test on a secondary battery.

[0002] In recent years, hybrid vehicles, plug-in hybrid vehicles, and electric vehicles have become increasingly popular. These vehicles are equipped with rechargeable secondary batteries as drive batteries. As a technology related to such drive batteries, for example, Patent Document 1 discloses a charge / discharge test system that tests drive batteries connected in parallel as test batteries. This charge / discharge test system tests the test battery while sharing power (energy) between the test battery and a non-test battery, which is a secondary battery not being tested.

[0003] JP 2023-10581 A

[0004] In the above-described charge / discharge test system, the higher the proportion of the power sharing period in the test period, the more energy can be saved. Therefore, there is a demand for the charge / discharge test system to increase the proportion of the power sharing period in the test period.

[0005] A charge / discharge test system that solves the above problem includes a bidirectional AC / DC converter connected to an AC bus and a DC bus, a first bidirectional DC / DC converter connected to the DC bus and a test battery (a secondary battery to be tested), a second bidirectional DC / DC converter connected to the DC bus and a non-test battery (a secondary battery not to be tested), and a control device that controls the operation of the first and second bidirectional DC / DC converters so that power is shared between the test battery and the non-test battery via the DC bus during the charge / discharge test, and controls the operation of the bidirectional AC / DC converter in response to a power surplus or deficiency on the DC bus. The control device performs a voltage acquisition process that acquires a voltage of the non-test battery, a voltage determination process that determines whether a forcing condition set for the voltage is met, and a forcing process that, if the forcing condition is met, controls the operation of the second bidirectional DC / DC converter so that the forcing condition is not met, thereby forcibly discharging or forcibly charging the non-test battery.

[0006] a first bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a test battery, which is a secondary battery that is the subject of the charge / discharge test; a second bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a non-test battery, which is a secondary battery that is not the subject of the charge / discharge test; and a control device that controls operation of the first bidirectional DC / DC converter and the second bidirectional DC / DC converter so that power is shared between the test battery and the non-test battery via the DC bus during the charge / discharge test, and controls operation of the bidirectional AC / DC converter in accordance with an excess or shortage of power on the DC bus, in which the control device obtains a reference voltage, which is the voltage of the non-test battery, and determines whether a compulsory condition set for the reference voltage is met; and if the compulsory condition is met, controls operation of the second bidirectional DC / DC converter to forcibly discharge or charge the non-test battery so that the compulsory condition is not met.

[0007] The program for solving the above problem includes a bidirectional AC / DC converter having one end connected to an AC bus and the other end connected to a DC bus, a first bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a test battery which is a secondary battery that is the subject of a charge / discharge test, a second bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a non-test battery which is a secondary battery that is not the subject of the charge / discharge test, and a control circuit for controlling the first bidirectional DC / DC converter and the second bidirectional DC / DC converter so that power is shared between the test battery and the non-test battery via the DC bus during the charge / discharge test. a control device that controls the operation of a second bidirectional DC / DC converter and that controls the operation of the bidirectional AC / DC converter in accordance with the excess or shortage of power in the DC bus, and causes the control device to execute a judgment voltage acquisition process that acquires a judgment voltage that is the voltage of the non-test battery, a voltage judgment process that judges whether a forced condition set for the judgment voltage is met, and a compulsion process that controls the operation of the second bidirectional DC / DC converter to forcibly discharge or forcibly charge the non-test battery so that the forcible condition is not met when the forcible condition is met.

[0008] According to the present disclosure, the proportion of the power sharing period in the test period can be increased.

[0009] FIG. 1 is a diagram showing a schematic configuration of a charge / discharge test system in the first embodiment. In the first embodiment, FIG. 2(a) is a diagram showing an example of power sharing, and FIG. 2(b) is a diagram showing another example of power sharing. FIG. 3 is a flowchart showing an example of a forced boost process in the first embodiment. FIG. 4 is a flowchart showing an example of a forced charge process in the first embodiment. FIG. 5 is a flowchart showing an example of a forced discharge process in the first embodiment. FIG. 6 is a graph showing an example of a transition of a determination voltage including forced charging in the first embodiment. FIG. 7 is a graph showing an example of a transition of a determination voltage including forced discharge in the first embodiment. FIG. 8 is a flowchart showing an example of a forced boost process in the second embodiment. FIG. 9 is a graph for explaining a lower limit determination range and an upper limit determination range in the second embodiment. FIG. 10 is a graph for explaining an allowable decrease amount in the second embodiment. FIG. 11 is a graph for explaining an allowable increase amount in the second embodiment. FIG. 12 is a graph showing an example of a transition of a determination voltage due to a forced boost process in the second embodiment. Fig. 13 is a graph showing an example of a transition of power supply to other equipment in the third embodiment. Fig. 14 is a diagram showing a schematic configuration of a charge / discharge test system in the third embodiment. Fig. 15 is a flowchart showing an example of a forced condition setting process in the third embodiment.

[0010] First Embodiment A first embodiment of a charge / discharge test system, a charge / discharge test method, and a program will be described with reference to FIGS.

[0011] 1, a charge / discharge test system 10 performs charge / discharge tests on test batteries 11-1, 11-2, ..., 11-m (where m is an integer of 3 or greater) while sharing power (energy) between test batteries 11-1, 11-2, ..., 11-m and non-test batteries 12-1, 12-2, ..., 12-n (where n is an integer of 3 or greater). The test batteries 11-1, 11-2, ..., 11-m and non-test batteries 12-1, 12-2, ..., 12-n are, for example, various secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and all-solid-state batteries (or other devices capable of storing power, including large-capacity capacitors such as electric double layer batteries).

[0012] In the following description, when there is no need to distinguish between the test batteries 11-1, 11-2, ..., 11-m, they will simply be referred to as test batteries 11, and when there is no need to distinguish between the non-test batteries 12-1, 12-2, ..., 12-n, they will simply be referred to as non-test batteries 12. In addition, in this embodiment, the charge / discharge test system 10 includes three or more test batteries 11 and three or more non-test batteries 12, but the charge / discharge test system 10 may include only less than three test batteries 11, and the charge / discharge test system 10 may include only less than three non-test batteries 12.

[0013] The charge / discharge test system 10 is connected to an AC bus 3. The AC bus 3 is connected to an AC power source 4 as well as other equipment 5 in a facility such as a factory in which the charge / discharge test system 10 is installed. The AC bus 3 supplies AC power to the charge / discharge test system 10 and the other equipment 5.

[0014] The charge / discharge test system 10 includes a bidirectional AC / DC converter 13, first bidirectional DC / DC converters 14-1, 14-2, . . . , 14-m, second bidirectional DC / DC converters 15-1, 15-2, .

[0015] In the following, the bidirectional AC / DC converter 13 will be simply referred to as the AC / DC converter 13. When there is no need to distinguish between the first bidirectional DC / DC converters 14-1, 14-2, ..., 14-m, they will simply be referred to as the DC / DC converter 14. When there is no need to distinguish between the second bidirectional DC / DC converters 15-1, 15-2, ..., 15-n, they will simply be referred to as the DC / DC converter 15. In addition, in FIG. 1, the bidirectional AC / DC converter will be simply referred to as AC / DC, and the bidirectional DC / DC converter will be simply referred to as DC / DC.

[0016] (Bidirectional AC / DC Converter) One end of the AC / DC converter 13 is connected to the AC bus 3. The other end of the AC / DC converter 13 is connected to the DC bus 16. The AC / DC converter 13 converts AC power on the AC bus 3 into DC power and supplies it to the DC bus 16. The AC / DC converter 13 converts DC power on the DC bus 16 into AC power and supplies it to the AC bus 3. The operation of the AC / DC converter 13 is controlled by the control device 20.

[0017] (First Bidirectional DC / DC Converter) One end of the DC / DC converter 14 is connected to the AC / DC converter 13 via the DC bus 16. The other end of the DC / DC converter 14 is connected to the test battery 11. The DC / DC converter 14 charges and discharges the test battery 11. The DC / DC converter 14 discharges the test battery 11 by outputting the power stored in the test battery 11 to the DC bus 16. The DC / DC converter 14 charges the test battery 11 by supplying DC power from the DC bus 16 to the test battery 11. The operation of this DC / DC converter 14 is controlled by the control device 20. The DC / DC converter 14 also detects various pieces of information related to the test battery 11, such as the voltage of the test battery 11, the charging power during charging, and the discharging power during discharging. The DC / DC converter 14 outputs the various pieces of information about the test battery 11 detected to the control device 20.

[0018] (Second Bidirectional DC / DC Converter) One end of the DC / DC converter 15 is connected to the AC / DC converter 13 via the DC bus 16. The other end of the DC / DC converter 15 is connected to the non-test battery 12. The DC / DC converter 15 charges and discharges the non-test battery 12. The DC / DC converter 15 discharges the non-test battery 12 by outputting the power stored in the non-test battery 12 to the DC bus 16. The DC / DC converter 15 charges the non-test battery 12 by supplying the DC power on the DC bus 16 to the non-test battery 12. The operation of the DC / DC converter 15 is controlled by the control device 20. The DC / DC converter 15 also detects various information related to the non-test battery 12, including the voltage of the non-test battery 12, the charging power during charging, and the discharging power during discharging. The DC / DC converter 15 outputs the detected various information about the non-test battery 12 to the control device 20.

[0019] (Control Device) The control device 20 may be realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Furthermore, some or all of the components of the control device 20 may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware. The program may be stored in advance in a storage device (not shown) equipped with a non-transitory storage medium such as an HDD (Hard Disk Drive) or flash memory provided in the control device 20. The control device 20 may be realized, for example, by including a programmable logic controller (PLC).

[0020] The control device 20 executes a test process that controls the operation of the DC / DC converter 14 so that the test battery 11 is charged and discharged according to a preset test pattern. The control device 20 executes a power sharing process that controls the operation of the DC / DC converter 15 so that power is shared between the test battery 11 and non-test batteries 12.

[0021] As shown in Figure 2(a), in the power sharing process, when the control device 20 controls the test battery 11 to be in a discharging state, it controls the DC / DC converter 15 so that the discharge power of the test battery 11 is supplied to the non-test batteries 12 via the DC bus 16. Also, as shown in Figure 2(b), when the control device 20 controls the test battery 11 to be in a charging state, it controls the DC / DC converter 15 so that the power stored in the non-test batteries 12 is supplied to the test batteries 11 via the DC bus 16. Based on the input voltages of each non-test battery 12, the control device 20 controls the DC / DC converter 15 so that the voltages of the non-test batteries 12 are uniform.

[0022] The control device 20 executes a supply / regeneration process that controls the operation of the AC / DC converter 13 based on the power surplus or deficiency in the DC bus 16. In the supply / regeneration process, when there is a power shortage in the DC bus 16, the control device 20 controls the AC / DC converter 13 so that the shortage of power is supplied to the DC bus 16. When there is surplus power in the DC bus 16, the control device 20 controls the AC / DC converter 13 so that the surplus power is regenerated to the AC bus 3.

[0023] The control device 20 repeatedly executes a forced boost process in parallel with the power sharing process. The forced boost process is a process that forcibly charges and discharges the non-test battery 12 regardless of the charge / discharge state of the test battery 11. In the forced boost process, the control device 20 determines whether a forced condition that sets the voltage of the non-test battery 12 as the determination voltage Vj is met. When the forced condition is met, the control device 20 interrupts the power sharing process and controls the operation of the DC / DC converter 15 so that the forced condition is not met.

[0024] (Forced Boost Process) The forced boost process will be described with reference to Figures 3 to 5. The control device 20 repeatedly executes a first forced boost process as a forced boost process during testing of the test battery 11. The first forced boost process is a process that forcibly charges and discharges the non-test battery 12 so that the capacity of the non-test battery 12 is utilized to the maximum.

[0025] As shown in Figure 3, in the first forced boost process, the control device 20 acquires the judgment voltage Vj of the non-test battery 12 (judgment voltage acquisition process: step S101). Next, the control device 20 compares the acquired judgment voltage Vj with the forced charge voltage V1 and the forced discharge voltage V2 (voltage judgment process: step S102). The forced charge voltage V1 is a value close to the lower limit usable voltage Vmin of the non-test battery 12, or is the same value as the lower limit usable voltage Vmin. The forced discharge voltage V2 is a value close to the upper limit usable voltage Vmax of the non-test battery 12, or is the same value as the upper limit usable voltage Vmax.

[0026] If the determination voltage Vj is equal to or greater than the forced charging voltage V1 and equal to or less than the forced discharging voltage V2, the control device 20 temporarily ends the first forced boost process (step S102: YES).

[0027] If the determination voltage Vj is lower than the forced charging voltage V1 (step S102: Vj<V1), the control device 20 determines that the forced charging condition is met, suspends the power sharing process, and executes a forced charging process, which is one of the forced processes (step S103). The forced charging process forcibly charges the non-test battery 12 that has been sufficiently discharged by the power sharing process, and is performed regardless of the charge / discharge state of the test battery 11. When the forced charging process ends, the control device 20 temporarily terminates the first forced boost process.

[0028] On the other hand, if the determination voltage Vj is higher than the forced discharge voltage V2 (step S102: V2<Vj), the control device 20 determines that the forced discharge condition is met, suspends the power sharing process, and executes a forced discharge process, which is one of the forced processes (step S104). The forced discharge process forcibly discharges the non-test battery 12 that has been fully charged by the power sharing process, and is performed regardless of the charge / discharge state of the test battery 11. When the forced discharge process ends, the control device 20 temporarily terminates the first forced boost process.

[0029] (Forced Charging Process) As shown in FIG. 4, in the forced charging process, the control device 20 controls the DC / DC converter 15 to charge the non-test battery 12 (step S201).

[0030] When the non-test battery 12 is controlled to be in a charging state, the control device 20 controls the AC / DC converter 13 so that when the test battery 11 is in a charging state, the sum of the charging power of the test battery 11 and the charging power of the non-test battery 12 is supplied to the DC bus 16.

[0031] Furthermore, when the test battery 11 is in a discharging state, the discharged power is supplied to the non-test batteries 12 through the DC bus 16. If the discharged power of the test battery 11 is greater than the charged power of the non-test batteries 12, the control device 20 controls the AC / DC converter 13 so that the surplus power in the DC bus 16 is regenerated to the AC bus 3. On the other hand, if the discharged power of the test battery 11 is less than the charged power of the non-test batteries 12, the control device 20 controls the AC / DC converter 13 so that the shortage of DC power is supplied to the DC bus 16.

[0032] Next, the control device 20 acquires the reference voltage Vj of the non-test battery 12 (step S202), and then determines whether the reference voltage Vj has reached the discharge start voltage V1d (step S203). The discharge start voltage V1d is a voltage lower than the forced discharge voltage V2.

[0033] If the determination voltage Vj has not reached the discharge start voltage V1d (step S203: NO), the control device 20 repeatedly executes steps S202 and S203. On the other hand, if the determination voltage Vj has reached the discharge start voltage V1d (step S203: YES), the control device 20 resumes the power sharing process (step S204) and ends the forced charging process.

[0034] (Forced Discharge Process) As shown in FIG. 5, in the forced discharge process, the control device 20 controls the DC / DC converter 15 to put the non-test battery 12 into a discharge state (step S301).

[0035] When the non-test battery 12 is controlled to be in a discharging state, the control device 20 controls the AC / DC converter 13 so that when the test battery 11 is in a discharging state, the sum of the discharge power of the test battery 11 and the discharge power of the non-test battery 12 is regenerated to the AC bus 3.

[0036] Furthermore, when the test battery 11 is in a charging state, the discharge power of the non-test battery 12 is supplied to the test battery 11 through the DC bus 16. If the charge power of the test battery 11 is greater than the discharge power of the non-test battery 12, the control device 20 controls the AC / DC converter 13 so that the shortage of DC power is supplied to the DC bus 16. On the other hand, if the discharge power of the non-test battery 12 is greater than the charge power of the test battery 11, the control device 20 controls the AC / DC converter 13 so that the surplus power on the DC bus 16 is regenerated and sent to the AC bus 3.

[0037] Next, the control device 20 acquires the reference voltage Vj of the non-test battery 12 (step S302), and then determines whether the reference voltage Vj has reached the charge start voltage V2c (step S303). The charge start voltage V2c is a voltage higher than the forced charge voltage V1.

[0038] If the determination voltage Vj has not reached the charge start voltage V2c (step S303: NO), the control device 20 repeatedly executes steps S302 and S303. On the other hand, if the determination voltage Vj has reached the charge start voltage V2c (step S303: YES), the control device 20 resumes the power sharing process (step S304) and ends the forced discharge process.

[0039] 6, when the forced charging condition (Vj<V1) is met during the power sharing process, the control device 20 interrupts the power sharing process and forcibly charges the non-test battery 12. Then, when the determination voltage Vj reaches the discharge start voltage V1d, the control device 20 resumes the power sharing process.

[0040] 7, if the forced discharge condition (V2<Vj) is met during the power sharing process, the control device 20 interrupts the power sharing process and forcibly discharges the non-test battery 12. Then, when the determination voltage Vj reaches the charge start voltage V2c, the control device 20 resumes the power sharing process.

[0041] The effects of the first embodiment will be described. (1-1) The charge / discharge test system 10 can reduce the state in which the non-test battery 12 is maintained at the upper limit voltage Vmax or the lower limit voltage Vmin. This allows the capacity of the non-test battery 12 to be effectively utilized when power is shared between the test battery 11 and the non-test battery 12. As a result, the power sharing period takes up a larger proportion of the test period, thereby further improving energy conservation in the charge / discharge test system.

[0042] (1-2) Furthermore, the non-test battery 12 is prevented from entering an over-discharged or over-charged state. As a result, the life of the non-test battery 12 can be extended. (1-3) When the forced charging condition is met, the control device 20 maintains the non-test battery 12 in a charged state until the determination voltage Vj reaches the discharge start voltage V1d. Since the discharge start voltage V1d is lower than the forced discharge voltage V2, the test battery 11 can charge the non-test battery 12 even if the test battery 11 is in a discharged state when the power sharing process is resumed. As a result, the proportion of the power sharing period can be increased.

[0043] (1-4) When the forced discharge condition is met, the control device 20 maintains the non-test battery 12 in a discharged state until the determination voltage Vj reaches the charge start voltage V2c. Since the charge start voltage V2c is higher than the forced charge voltage V1, the non-test battery 12 can charge the test battery 11 even if the test battery 11 is in a charging state when the power sharing process is resumed. As a result, the proportion of the power sharing period can be increased.

[0044] Second Embodiment A second embodiment of a charge / discharge test system, a charge / discharge test method, and a program will be described with reference to Figures 8 to 12. The charge / discharge test system, the charge / discharge test method, and the program of the second embodiment differ from the charge / discharge test system, the charge / discharge test method, and the program of the first embodiment only in the forced boost processing. Therefore, in the second embodiment, the forced boost processing will be described in detail, and the same parts as in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

[0045] In the second embodiment, the control device 20 repeatedly executes a second forced boost process as a forced boost process during testing of the test battery 11. The second forced boost process is a process that forcibly charges and discharges the non-test battery 12 so that the determination voltage Vj fluctuates between the lower limit usable voltage Vmin and the upper limit usable voltage Vmax while maintaining a balance.

[0046] 8, in the second forced boost process, the control device 20 acquires a determination voltage Vj (determination voltage acquisition process: step S401). Next, the control device 20 compares the determination voltage Vj with a lower limit threshold voltage V3 and an upper limit threshold voltage V4 (step S402: first voltage determination process).

[0047] As shown in FIG. 9 , the lower threshold voltage V3 is closer to the lower limit voltage Vmin than the median value Vmid between the lower limit voltage Vmin and the upper limit voltage Vmax of the non-test battery 12. In FIG. 9 , the range of voltages lower than the lower threshold voltage V3, indicated by the diagonal lines slanting downward to the left, is referred to as the lower limit judgment range. The upper threshold voltage V4 is closer to the upper limit voltage Vmax than the median value Vmid between the lower limit voltage Vmin and the upper limit voltage Vmax of the non-test battery 12. In FIG. 9 , the range of voltages higher than the upper threshold voltage V4, indicated by the diagonal lines slanting downward to the right, is referred to as the upper limit judgment range. The range equal to or greater than the lower threshold voltage V3 and equal to or less than the upper threshold voltage V4 is referred to as the boost-unnecessary range. That is, in step S402, it is determined which range the judgment voltage Vj is in.

[0048] When the determination voltage Vj is within the boost-unnecessary range (step S402: YES), the control device 20 temporarily terminates the second forced boost process. When the determination voltage Vj is within the lower-limit determination range (step S402: Vj≦V3), the control device 20 calculates the voltage drop ΔVj(−) of the determination voltage Vj per unit time Δt in the most recent period. The control device 20 then determines whether the calculated voltage drop ΔVj(−) is greater than the allowable voltage drop ΔVp(−) (second voltage determination process: step S403). In other words, the control device 20 determines whether the determination voltage Vj has dropped by a larger amount than the allowable voltage drop ΔVp(−).

[0049] 10 , the allowable voltage drop ΔVp(−) is the amount of voltage drop that will cause the determination voltage Vj1 at time t1 to reach the lower limit voltage Vmin at time t2 after a predetermined time has elapsed. The allowable voltage drop ΔVp(−) may be set for each determination voltage Vj in the lower limit determination range. In this case, it is preferable to set the allowable voltage drop ΔVp(−) to a smaller value as the determination voltage Vj is closer to the lower limit voltage Vmin.

[0050] If the voltage drop ΔVj(−) is greater than the allowable drop ΔVp(−) (step S403: YES), the control device 20 executes the forced charging process (step S404). On the other hand, if the voltage drop ΔVj(−) is equal to or less than the allowable drop ΔVp(−) (step S403: NO), the control device 20 temporarily ends the second forced boost process.

[0051] That is, if the determination voltage Vj is within the lower limit determination range and the voltage drop ΔVj(−) is greater than the allowable drop ΔVp(−), the control device 20 will execute the forced charging process, assuming that the forced charging conditions are met. In other words, the control device 20 will execute the forced charging process when it is expected that the voltage of the non-test battery 12 will reach the lower usable voltage limit Vmin.

[0052] When the determination voltage Vj is within the upper determination range (step S402: V4≦Vj), the control device 20 calculates the voltage increase amount ΔVj(+) of the determination voltage Vj per unit time Δt in the most recent period. Then, the control device 20 determines whether the calculated voltage increase amount ΔVj(+) is greater than the allowable increase amount ΔVp(+) (second voltage determination process: step S405). In other words, the control device 20 determines whether the determination voltage Vj is increasing by an amount greater than the allowable increase amount ΔVp(+).

[0053] 11 , the allowable increase amount ΔVp(+) is the amount of voltage increase that will cause the determination voltage Vj3 at time t3 to reach the upper limit voltage Vmax at time t4 after a predetermined time has elapsed. The allowable increase amount ΔVp(+) may be set for each determination voltage Vj in the upper limit determination range. In this case, it is preferable to set the allowable increase amount ΔVp(+) to a smaller value as the determination voltage Vj is closer to the upper limit voltage Vmax.

[0054] If the voltage increase amount ΔVj(+) is greater than the allowable increase amount ΔVp(+) (step S405: YES), the control device 20 executes the forced discharge process (step S406). On the other hand, if the voltage increase amount ΔVj(+) is equal to or less than the allowable increase amount ΔVp(+) (step S405: NO), the control device 20 temporarily ends the second forced boost process.

[0055] That is, when the determination voltage Vj is within the upper determination range and the voltage increase amount ΔVj(+) is greater than the allowable increase amount ΔVp(+), the control device 20 determines that the forced discharge condition is met and executes the forced discharge process. In other words, the control device 20 executes the forced discharge process when it is expected that the voltage of the non-test battery 12 will reach the upper limit usable voltage Vmax.

[0056] (Operation of Second Embodiment) As shown in FIG. 12 , when the forced charging condition (Vj≦V3, ΔVp(−)<ΔVj(−)) is met during the execution of the power sharing process, the control device 20 interrupts the power sharing process and executes the forced charging process. Furthermore, when the forced discharging condition (V4≦Vj, ΔVp(+)<ΔVj(+)) is met during the execution of the power sharing process, the control device 20 interrupts the power sharing process and executes the forced discharging process. Therefore, the determination voltage Vj changes while maintaining a balance between the lower usable voltage limit Vmin and the upper usable voltage limit Vmax.

[0057] The effects of the second embodiment will be described below. (2-1) The charge / discharge test system 10 can effectively prevent the non-test battery 12 from reaching the upper limit voltage Vmax or the lower limit voltage Vmin. As a result, the proportion of the power sharing period is further increased, and the charge / discharge test system 10 can achieve further energy savings.

[0058] (2-2) The non-test battery 12 is prevented from entering an over-discharged or over-charged state, thereby extending the life of the non-test battery 12. (2-3) By setting the allowable decrease amount ΔVp(−) to a smaller value as the determination voltage Vj approaches the lower limit voltage Vmin, the non-test battery 12 can be more effectively prevented from reaching the lower limit voltage Vmin.

[0059] (2-4) By setting the allowable increase amount ΔVp(+) to a smaller value for the determination voltage Vj that is closer to the upper limit of usable voltage Vmax, it is possible to more effectively prevent the non-test battery 12 from reaching the upper limit of usable voltage Vmax.

[0060] 13 to 15, a third embodiment of a charge / discharge test system, a charge / discharge test method, and a program will be described. Note that the charge / discharge test system, the charge / discharge test method, and the program of the third embodiment differ from the first and second embodiments in that the control device 20 executes a forced condition setting process. Therefore, in the third embodiment, the forced condition setting process will be described in detail, and the same parts as those of the first and second embodiments will be denoted by the same reference numerals and will not be described in detail again.

[0061] 13 , in a facility where a charge / discharge test system 10 is installed, the power supplied to other equipment 5 through the AC bus 3 often varies depending on the time of day. The charge / discharge test system 10 of the third embodiment aims to smooth the power supply from the AC power source 4 to the entire facility. Specifically, by giving priority to forced charging processing in non-peak times when the supply power W is equal to or less than a non-peak value W1, power is actively supplied from the AC bus 3 to the charge / discharge test system 10. Furthermore, by giving priority to forced discharging processing in peak times when the supply power W is equal to or greater than a peak value W2, power is actively regenerated from the charge / discharge test system 10 to the AC bus 3.

[0062] 14 , in the charge / discharge test system 10, supply status information 30 indicating the status of power supply from the AC bus 3 to the other equipment 5 is input to the control device 20. For example, the control device 20 receives, as the supply status information 30, the current total power consumption in real time from a higher-level power monitor that monitors the power consumption in the other equipment 5. Furthermore, for example, before a charge / discharge test, the control device 20 receives, as the supply status information 30, information that is generated in advance based on the monitoring results of the higher-level power monitor and that associates the total power consumption with each time period. Then, the control device 20 repeatedly executes a forced condition setting process based on the supply status information 30 in parallel with the forced boost process.

[0063] 15, in the forced condition setting process, the control device 20 acquires the supply power W based on the supply status information 30 (step S501). Next, the control device 20 compares the acquired supply power W with a non-peak value W1 and a peak value W2 (step S502).

[0064] If the supply power W is equal to or greater than the non-peak value W1 and equal to or less than the peak value W2 (step S502: YES), the control device 20 temporarily terminates the forcible condition setting process. If the supply power W is less than the non-peak value W1 (step S502: W<W1), the control device 20 sets the forcible condition for charging so that the non-test battery 12 is forcibly charged first (step S503). Then, when step S503 is completed, the control device 20 temporarily terminates the forcible condition setting process.

[0065] To explain step S503 in more detail, for example, the control device 20 executing the first forced boost process sets the forced charging voltage of the forced charging condition to a voltage greater than the forced charging voltage V1. For example, the control device 20 executing the second forced boost process sets the lower limit threshold voltage of the forced charging condition to a voltage greater than the lower limit threshold voltage V3, and sets the allowable decrease amount of the forced charging condition to a decrease amount smaller than the allowable decrease amount ΔVp(−). For example, the control device 20 sets the forced conditions so that only the forced charging process is performed as the forced process in the forced boost process.

[0066] If the supplied power W is greater than the peak value W2 (step S502: W2<W), the control device 20 sets the forced discharge conditions (step S504) so ​​that forced discharge of the non-test battery 12 is prioritized. After step S504 is completed, the control device 20 temporarily ends the forced condition setting process.

[0067] To explain step S504 in more detail, for example, the control device 20 executing the first forced boost process sets the forced discharge voltage of the forced discharge condition to a voltage lower than the forced discharge voltage V2. For example, the control device 20 executing the second forced boost process sets the upper limit threshold voltage of the forced charge condition to a voltage lower than the upper limit threshold voltage V4, and sets the allowable increase amount of the forced charge condition to a smaller increase amount than the allowable increase amount ΔVp(+). For example, the control device 20 sets the forced conditions so that only the forced discharge process is performed as the forced process in the forced boost process.

[0068] The operation and effects of the third embodiment will be described. (3-1) In the charge / discharge test system 10, the forced conditions are set based on the supply status information 30. As a result, when the supply power W is in a non-peak period, forced charging is given priority. Also, when the supply power W is in a peak period, forced discharging is given priority. As a result, the power supply from the AC power source 4 to the entire facility can be smoothed.

[0069] The first to third embodiments can be modified as follows: The first to third embodiments and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0070] The control device 20 may execute a first forced boost process and a second forced boost process. This configuration more reliably prevents the non-test battery 12 from becoming over-discharged or over-charged.

[0071] The control device 20 may perform the forced boost process by setting the forced condition as a forced charge condition and the forced process as a forced charge process. The control device 20 may perform the forced boost process by setting the forced condition as a forced discharge condition and the forced process as a forced discharge process.

[0072] 3...AC bus, 4...AC power source, 5...equipment, 10...charge / discharge test system, 11...test battery, 12...non-test battery, 13...bidirectional AC / DC converter, 14...first bidirectional DC / DC converter, 15...second bidirectional DC / DC converter, 16...DC bus, 20...control device, 30...supply status information.

Claims

1. A charge / discharge test system comprising: a bidirectional AC / DC converter having one end connected to an AC bus and the other end connected to a DC bus; a first bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a test battery, which is a secondary battery that is the subject of a charge / discharge test; a second bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a non-test battery, which is a secondary battery that is not the subject of the charge / discharge test; and a control device that controls operation of the first bidirectional DC / DC converter and the second bidirectional DC / DC converter so that power is shared between the test battery and the non-test battery via the DC bus during the charge / discharge test, and controls operation of the bidirectional AC / DC converter in accordance with excess or shortage of power on the DC bus, wherein the control device performs a judgment voltage acquisition process to acquire a judgment voltage, which is the voltage of the non-test battery; a voltage judgment process to judge whether a compulsory condition set for the judgment voltage is met; and a compulsory process to control operation of the second bidirectional DC / DC converter so that the compulsory condition is not met, and perform a forcible discharge or forcible charge of the non-test battery when the compulsory condition is met. Charge / discharge test system.

2. The charge / discharge test system according to claim 1, wherein the forced condition includes a forced charging condition in which the determination voltage reaches a forced charging voltage, and the control device maintains the non-test battery in a charging state in the forced processing until the determination voltage reaches a discharge start voltage.

3. The charge / discharge test system according to claim 1, wherein the forced condition includes a forced discharge condition in which the determination voltage reaches a forced discharge voltage, and the control device maintains the non-test battery in a discharged state in the forced processing until the determination voltage reaches a charge start voltage.

4. The charge / discharge test system according to claim 1, wherein the forced conditions include a forced discharge condition in which the judgment voltage is a value within an upper judgment range and the amount of increase in the judgment voltage per unit time is greater than an allowable increase amount, and a forced charge condition in which the judgment voltage is a value within a lower judgment range and the amount of decrease in the judgment voltage per unit time is greater than an allowable decrease amount, and wherein the control device, in the forced processing, maintains the non-test battery in a discharged state until the judgment voltage reaches a charging start voltage when the forced discharge condition is met, and maintains the non-test battery in a charged state until the judgment voltage reaches a discharging start voltage when the forced charge condition is met.

5. The charge / discharge test system according to claim 1, wherein the control device acquires the power supply status from the AC bus to other equipment, and executes a compulsory condition setting process to set the compulsory conditions so that forced discharging of the non-test battery is given priority when the power supply status is in a peak zone, and to set the compulsory conditions so that forced charging of the non-test battery is given priority when the power supply status is in a non-peak zone.

6. A charge and discharge test method for a charge and discharge test system comprising: a bidirectional AC / DC converter having one end connected to an AC bus and the other end connected to a DC bus; a first bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a test battery, which is a secondary battery that is the subject of a charge and discharge test; a second bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a non-test battery, which is a secondary battery that is not the subject of the charge and discharge test; and a control device that controls the operation of the first bidirectional DC / DC converter and the second bidirectional DC / DC converter so that power is shared between the test battery and the non-test battery via the DC bus during the charge and discharge test, and controls the operation of the bidirectional AC / DC converter in accordance with excess or shortage of power on the DC bus, wherein the control device obtains a judgment voltage that is the voltage of the non-test battery, judges whether a compulsory condition set for the judgment voltage is met, and, if the compulsory condition is met, controls the operation of the second bidirectional DC / DC converter to forcibly discharge or charge the non-test battery so that the compulsory condition is not met.

7. A program applicable to a charge / discharge test system comprising: a bidirectional AC / DC converter having one end connected to an AC bus and the other end connected to a DC bus; a first bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a test battery, which is a secondary battery that is the subject of a charge / discharge test; a second bidirectional DC / DC converter having one end connected to the DC bus and the other end connected to a non-test battery, which is a secondary battery that is not the subject of the charge / discharge test; and a control device that controls the operation of the first bidirectional DC / DC converter and the second bidirectional DC / DC converter so that power is shared between the test battery and the non-test battery via the DC bus during the charge / discharge test, and controls the operation of the bidirectional AC / DC converter in accordance with excess or shortage of power in the DC bus, the program causing the control device to execute a judgment voltage acquisition process that acquires a judgment voltage, which is the voltage of the non-test battery; a voltage judgment process that judges whether a compulsory condition set for the judgment voltage is met; and a compulsory process that controls the operation of the second bidirectional DC / DC converter to forcibly discharge or forcibly charge the non-test battery so that the compulsory condition is not met, when the compulsory condition is met.

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