Power storage system, replacement inspection method, and replacement inspection program

Abstract

According to the present disclosure, an internal resistance estimation unit estimates an internal resistance of each of a plurality of power storage modules 10. A storage unit stores the estimated internal resistances of the plurality of power storage modules 10. A determination unit determines a replacement error of the power storage module 10. After one of the plurality of power storage modules 10 has been replaced, the internal resistance estimation unit re-estimates the internal resistance of each of the plurality of power storage modules 10. The determination unit reads the internal resistance of each of the plurality of power storage modules 10 before replacement stored in the storage unit, compares the read internal resistance of each of the plurality of power storage modules 10 before replacement with the internal resistance of each of the plurality of power storage modules 10 after replacement, and determines the presence or absence of the replacement error.

Description

Power storage system, replacement inspection method, and replacement inspection program , ,

[0004] , ,

[0003] ,

[0007] ,

[0006] , ,

[0005] ,

[0001] The present disclosure relates to a power storage system, a replacement inspection method, and a replacement inspection program used for backup power supplies of data centers and the like.

[0002] In recent years, the demand for data centers has been expanding due to the spread of generative AI. In a data center, ensuring power supply is important, and a power storage system using secondary batteries is installed to ensure power supply during the time until an emergency generator starts up in the event of a power outage. The power storage system generally has a configuration in which a plurality of power storage modules (also referred to as cell blocks) are connected in parallel.

[0003] The European battery regulations stipulate that recyclers need to be able to handle the replacement of power storage modules. During the replacement of a power storage module, basically the power of the microcontroller is turned off, so the microcontroller cannot detect whether the power storage module has been replaced. As a result, if it is accidentally replaced with an unintended power storage module, the power storage system may not operate as expected, increasing the risk of insecurity.

[0004] Patent Document 1 discloses a method of determining that a power storage element has been replaced when a discontinuity in the temporal change of the internal resistance of the power storage element is detected. For example, the internal resistance is calculated when the vehicle engine starts, and then the continuity of the internal resistance is checked. This method is for detecting unauthorized battery replacement and not for preventing an operator from accidentally replacing a power storage module with a different one from the original during the replacement of a power storage module. Also, it is not a method assuming a scenario where one of a plurality of power storage modules is replaced. <000001​​​​​​To solve the above problems, an energy storage system according to one aspect of the present disclosure comprises a plurality of energy storage modules connected in parallel, and a management unit for managing the plurality of energy storage modules. The management unit includes an internal resistance estimation unit for estimating the internal resistance of each of the plurality of energy storage modules, a storage unit for storing the estimated internal resistances of the plurality of energy storage modules, and a determination unit for determining whether there is an error in replacing the energy storage modules. After one of the plurality of energy storage modules is replaced, the internal resistance estimation unit re-estimates the internal resistance of each of the plurality of energy storage modules, and the determination unit reads the internal resistances of the plurality of energy storage modules before replacement stored in the storage unit, compares the read internal resistances of the plurality of energy storage modules before replacement with the internal resistances of the plurality of energy storage modules after replacement, and determines whether there is an error in replacement.

[0008] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between devices, systems, methods, computer programs, etc., are also valid forms of this disclosure.

[0009] According to this disclosure, in an energy storage system in which multiple energy storage modules are connected in parallel, it is possible to check whether one of the energy storage modules has been replaced correctly when it is replaced.

[0010] This diagram illustrates an example configuration of the energy storage system according to the embodiment. This diagram shows an example configuration of each energy storage module in Figure 1. This diagram shows an example configuration of the system management unit in Figure 1. This flowchart shows the flow of the energy storage module replacement inspection process using the energy storage system according to this embodiment.

[0011] Figure 1 is a diagram illustrating an example configuration of an energy storage system 1 according to an embodiment. The energy storage system 1 is used as a power supply system for a data center. Load 3 is a collective term for the numerous servers and storage devices installed in the data center. The emergency generator 4 is a generator that supplies power to load 3 in the event of a power outage in the commercial power grid 2, and for example, a diesel generator or a gas turbine generator is used. It takes several tens of seconds to several minutes from the time a power outage in the commercial power grid 2 is detected until the emergency generator 4 starts up. The energy storage system 1 can continue to supply backup power to load 3 during that time.

[0012] The energy storage system 1 includes multiple energy storage modules 10a-10f, multiple AC / DC modules 20a-20f, and a system management unit 30, all of which are housed in a single rack. A grounding cable is laid over the rack, providing protective grounding.

[0013] Multiple energy storage modules 10a-10f are connected in parallel and housed in the first shelf SH1. The first shelf SH1 is fixed to the rack with a grounding cable connected and is protected grounded. Each of the multiple energy storage modules 10a-10f is housed in a metal enclosure and functionally grounded by being fixed to the first shelf SH1 in a floating state. Each energy storage module 10 is equipped with a handle, allowing workers to easily insert the energy storage modules 10 into or remove them from the first shelf SH1.

[0014] Multiple AC / DC modules 20a-20f are connected in parallel and housed in the second shelf SH2. The second shelf SH2 is fixed to the rack with a grounding cable connected and is protected by earthing. Each of the multiple AC / DC modules 20a-20f is housed in a metal enclosure and is protected by earthing by being fixed to the second shelf SH2 with a grounding cable connected. Each AC / DC module 20 is equipped with a handle, allowing workers to easily insert the AC / DC module 20 into or remove the AC / DC module 20 from the second shelf SH2.

[0015] Multiple energy storage modules 10a-10f and multiple AC / DC modules 20a-20f are connected to a DC bus 40, and DC power is supplied to the load 3 from the multiple AC / DC modules 20a-20f or the multiple energy storage modules 10a-10f via the DC bus 40. An emergency generator 4 is also connected to the DC bus 40. The DC bus 40 is installed, for example, as a 48V DC line.

[0016] The number of AC / DC modules 20a-20f connected in parallel can be arbitrarily designed as long as sufficient redundancy is ensured. In some cases, the total cost may be lower when connecting many inexpensive AC / DC modules with relatively lower current tolerance in parallel than when connecting a few expensive AC / DC modules with high current tolerance in parallel. The number of energy storage modules 10a-10f connected in parallel is determined according to the required power capacity as a backup power source.

[0017] Each AC / DC module 20 converts the AC power supplied from the commercial power grid 2 into DC power while stepping it down, and outputs it to the DC bus 40. For example, it converts the 200-240V AC voltage supplied from the commercial power grid 2 into 48V DC power.

[0018] Multiple energy storage modules 10a-10f, multiple AC / DC modules 20a-20f, and the system management unit 30 are connected by a communication line 50 and can communicate with each other. The communication line 50 may be a metal cable or an optical fiber cable.

[0019] Figure 2 shows an example configuration of each energy storage module 10 in Figure 1. The energy storage module 10 includes a battery pack 11, a temperature sensor T1, a shunt resistor Rs, a module management unit 12, and a DC / DC converter 13. The battery pack 11 includes a plurality of cells E1-En connected in series. In this embodiment, 14 cells in series are assumed. Lithium-ion battery cells, nickel-metal hydride battery cells, lead-acid battery cells, etc., can be used as cells. Hereinafter, this specification assumes the use of lithium-ion battery cells (nominal voltage: 3.6-3.7V). In addition, in the series stage of each cell, multiple cells may be connected in parallel to increase the capacity.

[0020] A shunt resistor Rs is connected in series with multiple cells E1-En. The shunt resistor Rs functions as a current sensing element. A Hall element may be used instead of the shunt resistor Rs. A temperature sensor T1 is installed near the multiple cells E1-En to detect the temperature of the multiple cells E1-En. For example, a thermistor can be used for the temperature sensor T1. Although only one temperature sensor T1 is shown in Figure 2, multiple temperature sensors T1 may be installed within a single energy storage module 10.

[0021] The module management unit 12 includes a voltage detection unit 12a, a temperature detection unit 12b, a current detection unit 12c, a control unit 12d, and a communication unit 12e. The voltage detection unit 12a is composed of an AFE (Analog Front End) IC or an ASIC (Application Specific Integrated Circuit). The control unit 12d is composed of a microcontroller. The microcontroller includes a CPU, RAM, ROM, and I / O.

[0022] The voltage detection unit 12a is connected to each node of a plurality of series-connected cells E1-En by a plurality of voltage measurement lines, and measures the voltage of each cell E1-En by measuring the voltage between two adjacent voltage measurement lines. The voltage detection unit 12a includes a multiplexer and an A / D converter. The multiplexer outputs the voltages of the plurality of cells E1-En to the A / D converter in a predetermined order. The A / D converter converts the analog voltage input from the multiplexer into a digital value. The voltage detection unit 12a transmits the digitally converted voltage values ​​of each cell E1-En to the control unit 12d via a serial communication interface.

[0023] The temperature detection unit 12b includes a voltage divider resistor and an A / D converter. The A / D converter converts the analog voltage indicating the temperature divided by the temperature sensor T1 and the voltage divider resistor into a digital value. The temperature detection unit 12b transmits the converted digital temperature value to the control unit 12d via a serial communication interface.

[0024] The current detection unit 12c includes a differential amplifier and an A / D converter. The differential amplifier amplifies the voltage across the shunt resistor Rs and outputs it to the A / D converter. The A / D converter converts the analog voltage indicating the current flowing through the battery pack 11, which is input from the differential amplifier, into a digital value. The current detection unit 12c transmits the digitally converted current value to the control unit 12d via a serial communication interface.

[0025] The control unit 12d manages the battery pack 11 based on the voltage, current, and temperature of multiple cells E1-En detected by the voltage detection unit 12a, current detection unit 12c, and temperature detection unit 12b. For example, it performs State of Charge (SOC) management and equalization control of multiple cells E1-En.

[0026] The control unit 12d estimates the State of Cost (SOC) by combining the Open Circuit Voltage (OCV) method and the current integration method. The OCV method estimates the SOC based on the measured OCV of the cell and the SOC-OCV curve of the cell. The SOC-OCV curve of the cell is created in advance based on characteristic tests conducted by the battery manufacturer and registered in the control unit 12d at the time of shipment.

[0027] The current integration method is a method for estimating the State of Charge (SOC) based on the OCV at the start of charging and discharging of the cell and the integrated value of the measured current. In the current integration method, measurement errors in the current accumulate as the charging and discharging time increases. Therefore, it is preferable to use a weighted average of the SOC estimated by the current integration method and the SOC estimated by the OCV method.

[0028] The communication unit 12e performs predetermined communication control (for example, communication control compliant with standards such as RS-485, TCP / IP, and CAN) and communicates with other energy storage modules 10 or the system management unit 30 via the communication line 50.

[0029] The DC / DC converter 13 is connected between the battery pack 11 and the DC bus 40. The DC / DC converter 13 is a bidirectional DC / DC converter and can control the voltage or current of the DC power input from the DC bus 40 to charge the battery pack 11. The DC / DC converter 13 can also control the voltage or current of the DC power discharged from the battery pack 11 and output it to the DC bus 40.

[0030] If the control unit 12d detects overcharging, over-discharging, overcurrent, or a temperature anomaly in any of the cells E1-En while the energy storage module 10 is operating, it controls the DC / DC converter 13 to an off state to protect the cells E1-En. If a switch such as a relay or semiconductor switch is inserted between the DC / DC converter 13 and the DC bus 40, the control unit 12d may protect the cells E1-En by turning off the switch.

[0031] The control unit 12d calculates the voltage of the energy storage module 10 by adding the voltages of multiple cells E1-En. The control unit 12d converts the SOC of multiple cells E1-En into capacity and calculates the total capacity of the energy storage module 10 by summing the converted capacities. The control unit 12d converts the calculated total capacity of the energy storage module 10 into the SOC of the energy storage module 10. The control unit 12d transmits monitoring data, including the voltage, current, temperature, and SOC of the energy storage module 10, to the system management unit 30 via the communication line 50.

[0032] Figure 3 shows an example configuration of the system management unit 30 in Figure 1. The system management unit 30 is a controller that manages the entire energy storage system 1. The system management unit 30 includes a control unit 31, a non-volatile memory unit 32, and a communication unit 33. The control unit 31 includes an acquisition unit 31a, an internal resistance estimation unit 31b, and a determination unit 31c. The control unit 31 can be realized through the cooperation of hardware resources and software resources, or solely through hardware resources. Hardware resources can include a CPU, ROM, RAM, I / O, ASIC, FPGA, and other LSIs. Software resources can include programs such as firmware. The non-volatile memory unit 32 can use EEPROM (Electrically Erasable Programmable Read-Only Memory) or NAND flash memory.

[0033] The acquisition unit 31a acquires monitoring data, including voltage, current, temperature, and SOC, from each module management unit 12 of the multiple energy storage modules 10a-10f. When an operator replaces any of the energy storage modules 10, the operator operates the operation unit (not shown) of the energy storage system 1 to switch to replacement mode.

[0034] When the energy storage system 1 transitions to exchange mode, the internal resistance estimation unit 31b estimates the internal resistances of the multiple energy storage modules 10a-10f. The internal resistance estimation unit 31b generates a current change of a certain value or more over a predetermined time and estimates the internal resistance of each energy storage module 10 from the ratio of voltage change to current change over the predetermined time. For example, the internal resistance estimation unit 31b calculates the voltage change ΔV / current change ΔI over 10 to 30 seconds to estimate the internal resistance of each energy storage module 10.

[0035] The internal resistance estimation unit 31b transmits a current pattern for measuring the internal resistance to each module management unit 12 of the multiple energy storage modules 10a-10f. Each module management unit 12 controls each DC / DC converter 13 according to the current pattern for measuring the internal resistance received from the system management unit 30.

[0036] Each module management unit 12 calculates the internal resistance of each energy storage module 10 from the ratio of voltage change to current change of each energy storage module 10 over a predetermined time. Each module management unit 12 transmits the calculated internal resistance to the internal resistance estimation unit 31b of the system management unit 30. Alternatively, each module management unit 12 may continuously transmit the voltage and current values ​​of each energy storage module 10 to the internal resistance estimation unit 31b of the system management unit 30 over a predetermined time, and the internal resistance estimation unit 31b may calculate the internal resistance of each energy storage module 10 from the ratio of voltage change to current change of each energy storage module 10 over a predetermined time.

[0037] The internal resistance estimation unit 31b stores the estimated internal resistances of the multiple energy storage modules 10a-10f in the non-volatile memory unit 32. Once the internal resistances are stored, the internal resistance estimation unit 31b sends a power-off signal (shutdown signal) to each module management unit 12 of the multiple energy storage modules 10a-10f.

[0038] When each module management unit 12 receives a shutdown signal from the system management unit 30, it turns off the power to the DC / DC converter 13 and then shuts itself down. The system management unit 30 may shut down or remain powered on.

[0039] After confirming that multiple energy storage modules 10a-10f are shut down, the worker replaces one of the multiple energy storage modules 10a-10f with a new energy storage module 10. After replacing the energy storage module 10, the worker performs a replacement completion operation or a power-on operation (if the system management unit 30 is shut down) on the control unit (not shown).

[0040] When the internal resistance estimation unit 31b detects that the replacement of the energy storage module 10 has been completed due to the operator's replacement completion operation or power-on operation, it sends a power-on signal (start-up signal) to each module management unit 12 of the multiple energy storage modules 10a-10f. Each module management unit 12 starts up when it receives a start-up signal from the system management unit 30, and after starting up, it starts each DC / DC converter 13.

[0041] The internal resistance estimation unit 31b re - estimates the internal resistances of the plurality of power storage modules 10a - 10f. As a specific estimation method, the same method as the method estimated before the replacement described above can be used.

[0042] The determination unit 31c reads out the respective internal resistances of the plurality of power storage modules 10a - 10f before replacement stored in the non - volatile memory unit 32. The determination unit 31c compares the respective internal resistances of the plurality of power storage modules 10a - 10f before replacement read out with the respective internal resistances of the plurality of power storage modules 10a - 10f after replacement, and determines whether there is an error in the replacement of the power storage module 10.

[0043] Specifically, the determination unit 31c determines that the power storage module 10 whose internal resistance has decreased by a set value or more before and after replacement has been replaced. The determination unit 31c compares the internal resistance of the power storage module 10 determined to have been replaced with the average value or median value of the internal resistances of the other power storage modules 10.

[0044] If the values of both are less than the replacement determination threshold, the determination unit 31c determines that it has been replaced with the correct power storage module 10. The determination unit 31c saves the replacement log of the power storage module 10 including the date and time in the non - volatile memory unit 32.

[0045] If the values of both are deviated by the replacement determination threshold or more, the determination unit 31c determines that there is a replacement error. The determination unit 31c transmits a power - off signal (shutdown signal) to the module management unit 12 of the power storage module 10 targeted by the replacement error to prohibit the use of the power storage module 10 targeted by the replacement error. The determination unit 31c lights or blinks an error lamp (not shown) of the operation unit to notify the operator that a replacement error has occurred.

[0046] Figure 4 is a flowchart showing the flow of the replacement inspection process of the power storage module 10 by the power storage system 1 according to the present embodiment. When the power storage system 1 transitions to the replacement mode, the internal resistance estimation unit 31b estimates the internal resistance of each of the power storage modules 10a - 10f (S10). The internal resistance estimation unit 31b stores the estimated internal resistance of each of the power storage modules 10a - 10f in the non-volatile storage unit 32 (S11). After storing the internal resistance, the internal resistance estimation unit 31b turns off the power supply of the power storage system 1 or the plurality of power storage modules 10a - 10f (S12).

[0047] After the operator replaces one power storage module 10, due to the operator's operation, the power supply of the power storage system 1 or the plurality of power storage modules 10a - 10f is turned on (S13). The determination unit 31c reads out the internal resistance of each of the power storage modules 10a - 10f before replacement stored in the non-volatile storage unit 32 (S14). The internal resistance estimation unit 31b estimates the internal resistance of each of the power storage modules 10a - 10f again (S15).

[0048] The determination unit 31c compares the internal resistance of each of the power storage modules 10a - 10f before and after replacement (S16). The determination unit 31c determines that the power storage module 10 whose internal resistance has decreased by more than the set value has been replaced with the replaced power storage module 10 (S17). The determination unit 31c calculates the average value of the internal resistance of the power storage modules 10 that have not been replaced (S18). The determination unit 31c calculates the difference between the internal resistance of the replaced power storage module 10 and the calculated average value (S19).

[0049] The determination unit 31c compares the difference with the replacement determination threshold (S20). When the difference is less than the replacement determination threshold (Y in S20), the determination unit 31c determines that the correct power storage module 10 has been replaced and stores the replacement history in the non-volatile storage unit 32 (S21). When the difference is greater than or equal to the replacement determination threshold (N in S20), the determination unit 31c determines that the wrong power storage module 10 has been replaced, turns off the power supply of the power storage module 10 determined to be a replacement error, and sets it to prohibited from use (S22).

[0050] As described above, according to this embodiment, when a single energy storage module is replaced in the energy storage system 1, it is possible to inspect with high accuracy immediately after the replacement whether or not it has been replaced correctly. This makes it possible to determine whether there is a difference in the number of cells in parallel within the replaced energy storage module 10 or whether it has been replaced with an energy storage module 10 that is too degraded. For example, if an energy storage module 10 capable of discharging a current exceeding the rating of the energy storage system 1 is mistakenly replaced, there is a possibility that a current exceeding the rating will flow through the energy storage system 1, and safety cannot be guaranteed. In contrast, in this embodiment, if an incorrect energy storage module 10 is replaced, the risk of unsafety can be suppressed by prohibiting the use of the incorrectly replaced energy storage module 10.

[0051] The present disclosure has been described above based on embodiments. The embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure.

[0052] For example, after determining that the correct energy storage module 10 has been replaced, the determination unit 31c may inspect the variation in the internal resistance of the multiple energy storage modules 10a-10f. For example, the determination unit 31c calculates the difference between the maximum and minimum values ​​of the internal resistance of the multiple energy storage modules 10a-10f, and if this difference exceeds the variation determination threshold, it recommends replacing the energy storage module 10 with the maximum internal resistance. The variation determination threshold is set to a value smaller than the replacement determination threshold. In this case, the variation in internal resistance due to the variation in the progression of degradation among the multiple energy storage modules 10a-10f can be kept within a predetermined range. Since the variation in internal resistance among the multiple energy storage modules 10a-10f can lead to crosscurrent and a decrease in the overall performance of the energy storage system 1, it is desirable to keep it as small as possible.

[0053] In the above-described embodiment, an example was explained in which the internal resistance of each of the multiple energy storage modules 10a-10f before replacement is stored in the non-volatile memory unit 32. In this regard, when the power supply of the system management unit 30 is maintained when replacing the energy storage module 10, the internal resistance of each of the multiple energy storage modules 10a-10f before replacement may be temporarily stored in the RAM in the control unit 31.

[0054] In the above-described embodiment, an example was explained in which multiple energy storage modules 10a-10f are connected in parallel. However, if the voltage of the DC bus 40 is designed to be high, multiple energy storage modules 10 may be connected in series and parallel. Even in this case, the replacement inspection process for the energy storage modules 10 according to this embodiment can be applied. Furthermore, the energy storage system 1 according to this embodiment can be applied to purposes other than data center backup. For example, it can be applied to the application of charging power generated by a solar power generation system and discharging it to the commercial power grid 2 at a predetermined timing. In that case, since it is not necessary to step down the voltage to 48V, the energy storage system 1 may be configured to store power at a voltage close to the voltage of the commercial power grid 2 by connecting multiple energy storage modules 10 in series and parallel.

[0055] The embodiments may be specified by the following items.

[0056] [Item 1] The system comprises a plurality of parallel-connected energy storage modules (10a-10f), and a management unit (30) for managing the plurality of energy storage modules (10a-10f), wherein the management unit (30) includes: an internal resistance estimation unit (31b) for estimating the internal resistance of each of the plurality of energy storage modules (10a-10f), a storage unit (32) for storing the estimated internal resistances of the plurality of energy storage modules (10a-10f), and a determination unit (31c) for determining an error in replacing the energy storage modules, and after one of the plurality of energy storage modules (10a-10f) is replaced, the internal resistance estimation unit (31b) re-estimates the internal resistance of each of the plurality of energy storage modules (10a-10f), The energy storage system (1) is characterized in that the determination unit (31c) reads the internal resistance of each of the plurality of energy storage modules (10a-10f) before replacement stored in the storage unit (32), compares the read internal resistance of each of the plurality of energy storage modules (10a-10f) before replacement with the internal resistance of each of the plurality of energy storage modules (10a-10f) after replacement, and determines whether or not there is a replacement error. With this, when a single energy storage module (10) is replaced, it is possible to check whether or not it has been replaced correctly. [Item 2] The energy storage system (1) according to Item 1, wherein the determination unit (31c) determines that an energy storage module (10) whose internal resistance has decreased by a set value or more before and after replacement is the replaced energy storage module (10). With this, the replaced energy storage module (10) can be identified without installing a mounting detection sensor on the first shelf (SH1). [Item 3] The determination unit (31c) compares the internal resistance of the energy storage module (10) that has been determined to have been replaced with the average or median value of the internal resistance of the other energy storage modules (10), and determines that the replacement is an error if the two values ​​deviate by more than a predetermined threshold, as described in Item 2 of the energy storage system (1). This makes it possible to determine with high accuracy whether an incorrect energy storage module (10) has been replaced with one that was not intended.[Item 4] The storage unit (32) is a non-volatile storage unit (32), and before the replacement of the energy storage module, the power supply of the energy storage system (1) or the power supply of the multiple energy storage modules (10a-10f) is turned off, and after one energy storage module (10) is replaced by an operator, the power supply of the energy storage system (1) or the power supply of the multiple energy storage modules (10a-10f) is turned on, and the determination unit (31c) reads the internal resistance of each of the multiple energy storage modules (10a-10f) before replacement stored in the non-volatile storage unit (32), as described in Item 1. With this, even if the power is turned off, the internal resistance of the multiple energy storage modules (10a-10f) before replacement can be saved, and it is possible to compare the internal resistance before and after replacement. [Item 5] The energy storage system (1) described in Item 1, wherein the determination unit (31c) turns off the power to the energy storage module (10) that is the subject of the replacement error when it determines that the replacement error has occurred. This reduces the risk of unsafety. [Item 6] A replacement inspection method performed when one of a plurality of parallel-connected energy storage modules (10a-10f) is replaced, comprising: a step of estimating the internal resistance of each of the plurality of energy storage modules (10a-10f); a step of storing the estimated internal resistances of the plurality of energy storage modules (10a-10f) in a storage unit (32); a step of re-estimating the internal resistance of each of the plurality of energy storage modules (10a-10f) after one of the plurality of energy storage modules (10a-10f) has been replaced; and a step of reading the internal resistances of each of the plurality of energy storage modules (10a-10f) before replacement stored in the storage unit (32), comparing the read internal resistances of each of the plurality of energy storage modules (10a-10f) before replacement with the internal resistances of each of the plurality of energy storage modules (10a-10f) after replacement to determine whether or not there is a replacement error. According to this, when a single energy storage module (10) is replaced, it is possible to check whether or not it has been replaced correctly.[Item 7] A replacement inspection program to be executed by a computer when one of a plurality of parallel-connected energy storage modules (10a-10f) is replaced, characterized in that the computer is made to execute: a process to estimate the internal resistance of each of the plurality of energy storage modules (10a-10f); a process to store the estimated internal resistances of the plurality of energy storage modules (10a-10f) in a storage unit (32); a process to re-estimate the internal resistance of each of the plurality of energy storage modules (10a-10f) after one of the plurality of energy storage modules (10a-10f) has been replaced; and a process to read the internal resistances of each of the plurality of energy storage modules (10a-10f) before replacement stored in the storage unit (32), compare the read internal resistances of each of the plurality of energy storage modules (10a-10f) before replacement with the internal resistances of each of the plurality of energy storage modules (10a-10f) after replacement, and determine whether or not there is a replacement error. According to this, when a single energy storage module (10) is replaced, it is possible to check whether or not it has been replaced correctly.

[0057] This disclosure can be used for replacing energy storage modules in an energy storage system in which multiple energy storage modules are connected in parallel.

[0058] 1 Energy storage system, 2 Commercial power grid, 3 Load, 4 Emergency generator, 10 Energy storage module, 11 Battery pack, 12 Module management unit, 12a Voltage detection unit, 12b Temperature detection unit, 12c Current detection unit, 12d Control unit, 12e Communication unit, 13 DC / DC converter, E1-En cell, Rs shunt resistor, T1 Temperature sensor, SH1 First shelf, SH2 Second shelf, 20 AC / DC module, 30 System management unit, 31 Control unit, 31a Acquisition unit, 31b Internal resistance estimation unit, 31c Judgment unit, 32 Non-volatile memory unit, 33 Communication unit, 40 DC bus, 50 Communication line.

Claims

1. An energy storage system comprising: a plurality of energy storage modules connected in parallel; and a management unit for managing the plurality of energy storage modules, wherein the management unit includes: an internal resistance estimation unit for estimating the internal resistance of each of the plurality of energy storage modules; a storage unit for storing the estimated internal resistances of the plurality of energy storage modules; and a determination unit for determining whether there is an error in replacing the energy storage modules, wherein after one of the plurality of energy storage modules is replaced, the internal resistance estimation unit re-estimates the internal resistance of each of the plurality of energy storage modules; and the determination unit reads the internal resistances of the plurality of energy storage modules before replacement stored in the storage unit, compares the read internal resistances of the plurality of energy storage modules before replacement with the internal resistances of the plurality of energy storage modules after replacement, and determines whether there is an error in replacing the modules.

2. The energy storage system according to claim 1, wherein the determination unit determines that an energy storage module whose internal resistance has decreased by a set value or more before and after replacement is the energy storage module that has been replaced.

3. The energy storage system according to claim 2, wherein the determination unit compares the internal resistance of the energy storage module that has been determined to have been replaced with the average or median value of the internal resistance of the other energy storage modules, and determines that an exchange error has occurred if the two values ​​deviate by more than a predetermined threshold.

4. The storage unit is a non-volatile storage unit, and before the replacement of the energy storage module, the power supply of the energy storage system or the power supply of the plurality of energy storage modules is turned off, and after one energy storage module is replaced by an operator, the power supply of the energy storage system or the power supply of the plurality of energy storage modules is turned on, and when the power supply of the energy storage system or the power supply of the plurality of energy storage modules is turned on, the determination unit reads the internal resistance of each of the plurality of energy storage modules before replacement stored in the non-volatile storage unit, as described in claim 1.

5. The energy storage system according to claim 1, wherein the determination unit, when it determines that the replacement error has occurred, turns off the power to the energy storage module that is the subject of the replacement error.

6. A replacement inspection method performed when one of a plurality of parallel-connected energy storage modules is replaced, comprising: a step of estimating the internal resistance of each of the plurality of energy storage modules; a step of storing the estimated internal resistances of the plurality of energy storage modules in a memory unit; a step of re-estimating the internal resistance of each of the plurality of energy storage modules after one of the plurality of energy storage modules has been replaced; and a step of reading the internal resistances of the plurality of energy storage modules before replacement stored in the memory unit, comparing the read internal resistances of the plurality of energy storage modules before replacement with the internal resistances of the plurality of energy storage modules after replacement to determine whether or not there is a replacement error.

7. A replacement inspection program to be executed by a computer when one of a plurality of parallel-connected energy storage modules is replaced, characterized by causing the computer to execute: a process of estimating the internal resistance of each of the plurality of energy storage modules; a process of storing the estimated internal resistances of the plurality of energy storage modules in a memory unit; a process of re-estimating the internal resistance of each of the plurality of energy storage modules after one of the plurality of energy storage modules has been replaced; and a process of reading the internal resistances of the plurality of energy storage modules before replacement stored in the memory unit, comparing the read internal resistances of the plurality of energy storage modules before replacement with the internal resistances of the plurality of energy storage modules after replacement, and determining whether or not there is a replacement error.

Images