Secondary battery evaluation system

Abstract

This secondary battery evaluation system comprises: a battery pack (11) consisting of a plurality of secondary battery cells (111); a voltage detecting circuit (13) for detecting the voltage value across both ends of the battery pack (11); a current detecting circuit (12) for detecting the current value of the battery pack (11); a test secondary battery (190) consisting of at least one battery cell manufactured from the same materials as the secondary battery cells (111); and a test power supply circuit (19) for controlling charging and discharging of the test secondary battery (190). The test power supply circuit (19) simulates charging and discharging of the battery pack (11) by: setting a test charging voltage value and a test charging current value for the test secondary battery (190) on the basis of the voltage value across both ends of the battery pack (11) and the current value during charging, and charging the test secondary battery (190) using the test charging voltage value and the test charging current value; and setting a test discharging voltage value and a test discharging current value for the test secondary battery (190) on the basis of the voltage value across both ends of the battery pack (11) and the current value during discharging, and discharging the test secondary battery (190) using the test discharging voltage value and the test discharging current value. When measuring SOC-OCV data, the test power supply circuit (19) performs charging and discharging of the test secondary battery (190) independently of the drive of the battery pack (11) to acquire the SOC-OCV data of the test secondary battery (190).

Description

Secondary battery evaluation system

[0001] The present invention relates to a system for evaluating the degree of deterioration of a secondary battery.

[0002] Patent Document 1 describes a battery state detection device in which a battery (secondary battery) that supplies power to a vehicle motor or the like is used as a battery to be evaluated for its deterioration level, and a battery for monitoring the deterioration level is connected in parallel to the battery to be evaluated for its deterioration level.

[0003] The battery state detection device described in Patent Document 1 uses a monitoring battery to detect the state of a battery to be evaluated.

[0004] JP 2009-25032 A

[0005] However, in the device of Patent Document 1, the monitoring battery is also in operation while the battery to be evaluated is in operation, so while the battery to be evaluated is in operation, static evaluation such as OCV degradation analysis of the battery to be evaluated cannot be performed, and the degree of degradation cannot be accurately evaluated.

[0006] Furthermore, static evaluation such as OCV degradation analysis of the battery under evaluation requires a long time, which makes it unsuitable for systems that cannot be shut down, such as UPS batteries.

[0007] Therefore, an object of the present invention is to provide a secondary battery evaluation system that accurately evaluates the degree of deterioration of a battery (secondary battery) to be evaluated without stopping the operation of the battery to be evaluated.

[0008] The secondary battery evaluation system of the present invention includes a battery pack consisting of a plurality of secondary battery cells, a voltage detection circuit that detects the voltage value across the battery pack, a current detection circuit that detects the current value of the battery pack, a test secondary battery consisting of at least one battery cell made of the same material as the secondary battery cells, and a power supply circuit that controls the charging and discharging of the test secondary battery.

[0009] The power supply circuit sets a test charging voltage value and a test charging current value for the test secondary battery based on the voltage value and the current value at both ends of the battery pack when charging, charges the test secondary battery at the test charging voltage value and the test charging current value, sets a test discharging voltage value and a test discharging current value for the test secondary battery based on the voltage value and the current value at both ends of the battery pack when discharging, and discharges the test secondary battery at the test discharging voltage value and the test discharging current value, thereby simulating charging and discharging of the battery pack. When measuring the SOC-OCV data, the power supply circuit charges and discharges the test secondary battery independently from driving the battery pack, and acquires the SOC-OCV data of the test secondary battery.

[0010] This configuration allows the test secondary battery to be charged and discharged independently of the operation of the battery pack. This allows static evaluation of the test secondary battery even while the battery pack is in operation. Furthermore, because the test secondary battery is manufactured from the same materials as the secondary battery cells of the battery pack, if the deterioration characteristics of the test secondary battery can be measured, the deterioration characteristics of the battery pack can be indirectly determined with high accuracy.

[0011] According to the present invention, it is possible to accurately evaluate the degree of deterioration of a secondary battery to be evaluated without stopping the operation of the secondary battery to be evaluated.

[0012] FIG. 1 is a configuration diagram showing an example of a power system in which a secondary battery to be evaluated in an embodiment of the present invention is used. FIG. 2 is a functional block diagram showing an example of a secondary battery charge / discharge system including a secondary battery evaluation system according to a first embodiment of the present invention. FIG. 3 is a perspective view showing one aspect of a battery pack. FIG. 4 is a functional block diagram showing an example of a secondary battery charge / discharge system including a secondary battery evaluation system according to a second embodiment of the present invention. FIG. 5 is a functional block diagram showing an example of a secondary battery evaluation system according to a third embodiment of the present invention. FIG. 6 is a diagram showing an example of a schematic configuration of an EV to which a secondary battery evaluation system is applied. FIG. 7 is a functional block diagram showing an example of a battery module mounted on an EV. FIG. 8 is a functional block diagram showing an example of a test system configuration.

[0013] First Embodiment A secondary battery evaluation system according to a first embodiment of the present invention will be described with reference to the drawings.

[0014] (Power System Using Secondary Battery) Fig. 1 is a configuration diagram showing an example of a power system using a secondary battery to be evaluated in an embodiment of the present invention. As shown in Fig. 1, the power system 90 includes a battery module 10, a solar panel 20, a storage battery PCS 31, a solar power PCS 32, a system control unit 40, a grid interconnection relay 50, a current sensor 60, and a business load.

[0015] The power system 90 is not limited to a system in which the type of load is a business load, and the configuration of the present invention can be applied and effectively functions in any system in which the secondary battery (storage battery) of the battery module 10 is driven (charged and discharged) almost continuously. Also, although the power system 90 includes the solar panel 20 and the solar PCS 32, these may be omitted.

[0016] The battery module 10 is connected to a storage battery PCS 31. The solar panel 20 is connected to a solar light PCS 32. The storage battery PCS 31 and the solar light PCS 32 are connected to a grid interconnection relay 50. The grid interconnection relay 50 is connected to a commercial power system. A current sensor 60 is arranged in the connection line between the grid interconnection relay 50 and the commercial power system.

[0017] The battery module 10 is a so-called ESS (Energy Storage System) and includes a plurality of secondary battery cells 111. The plurality of secondary battery cells 111 are charged or discharged under charge / discharge control from a storage battery PCS 31. A more specific configuration of the battery module 10 will be described later.

[0018] The system control unit 40 controls the operation of the storage battery PCS 31 and the solar power PCS 32 so that the power of the business load is supplied by power from the solar power PCS 32 and power from the battery module 10. For example, the system control unit 40 predicts the power of the business load, and if the power of the business load can be supplied by the power generated by solar power and the power purchased up to the contract upper limit, performs control to supply the power generated by solar power and the power purchased up to the contract upper limit to the business load. At this time, the system control unit 40 controls the operation of the solar power PCS 32 based on the current measured by the current sensor 60 so as to prevent power from flowing back into the commercial power grid.

[0019] In addition, if the power generated by solar power generation and the purchased power up to the contract limit cannot cover the power required for the business load and the battery module 10 is sufficiently charged, the system control unit 40 instructs the battery PCS 31 to control discharge from the battery module 10.

[0020] In addition, if the system control unit 40 can cover the power of the business load with the power generated by solar power generation and purchased power up to the contract limit, and if there is surplus power in the solar power generation and the battery module 10 has a chargeable capacity, it instructs the battery PCS 31 to control charging of the battery module 10.

[0021] The storage battery PCS 31 controls the charging and discharging of the multiple secondary battery cells 111 of the battery module 10 based on instructions from the system control unit 40 .

[0022] (Secondary Battery Evaluation System) Fig. 2 is a functional block diagram showing an example of a secondary battery charge / discharge system including a secondary battery evaluation system according to the first embodiment of the present invention. As shown in Fig. 2, the secondary battery charge / discharge system includes a battery module 10 and a storage battery PCS 31.

[0023] The storage battery PCS 31 includes a microcomputer 311 and a DC-DC converter 312. The battery module 10 includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, a test power supply circuit 19, and a test secondary battery 190.

[0024] The battery pack 11 is configured by connecting a plurality of secondary battery cells 111 in series and in parallel. Fig. 3 is a perspective view showing one embodiment of the battery pack. The plurality of secondary battery cells 111 are grouped together in a two-dimensional arrangement as shown in Fig. 3, for example, to configure the battery pack 11.

[0025] The positive and negative terminals of the battery pack 11 are connected to the DCDC converter 312 of the storage battery PCS 31 .

[0026] The current detection circuit 12 is connected between the positive terminal of the battery pack 11 and the DCDC converter 312. The output terminal of the current detection circuit 12 is connected to the microcomputer 311. This allows the microcomputer 311 to obtain the current value of the battery pack 11.

[0027] The voltage detection circuit 13 is connected between the positive and negative terminals of the battery pack 11. The output terminal of the voltage detection circuit 13 is connected to the microcomputer 311. This allows the microcomputer 311 to obtain the voltage value across the battery pack 11. The voltage detection circuit 13 may be configured to individually detect the cell voltages of the multiple secondary battery cells in the battery pack, and output the sum of these cell voltages as the voltage across the battery pack 11.

[0028] The microcomputer 311 receives operational control from the system control unit 40 and controls charging and discharging of the DCDC converter 312. At this time, the microcomputer 311 controls charging and discharging based on the current value from the current detection circuit 12 and the voltage value from the voltage detection circuit 13.

[0029] The test secondary battery 190 is manufactured from the same material as the multiple secondary battery cells 111. In other words, the test secondary battery 190 is the same as one of the secondary battery cells 111. The test secondary battery 190 may be composed of multiple secondary battery cells 111, as long as the number of the secondary battery cells 111 is less than the number of the secondary battery cells 111 that make up the battery pack 11. However, it is preferable that the number of the secondary battery cells 111 is small. This simplifies the configuration of the test secondary battery 190, making it possible to reduce the size and cost.

[0030] The positive and negative terminals of the test secondary battery 190 are connected to the test power supply circuit 19 .

[0031] The test power supply circuit 19 includes a charging circuit and an electronic load. The test power supply circuit 19 controls the charging of the test secondary battery 190 using the charging circuit. The test power supply circuit 19 controls the discharging of the test secondary battery 190 using the electronic load.

[0032] The test power supply circuit 19 is connected to the microcomputer 311 of the storage battery PCS 31 and the measurement data transmission unit 18. The measurement data transmission unit 18 may be disposed inside or outside the battery module 10.

[0033] (Simulation of charging and discharging of battery pack 11) The test power supply circuit 19 acquires the charging conditions (charging current value, charging voltage value) of the battery pack 11 from the microcomputer 311. The test power supply circuit 19 sets the charging voltage value and charging current value per unit cell of the multiple secondary battery cells 111 that make up the battery pack 11 to be the same as the test charging voltage value and test charging current value per unit cell of the test secondary battery 190.

[0034] For example, the test charging voltage value is set by dividing the voltage value across the battery pack 11 during charging by the number of secondary battery cells 111 connected in series in the battery pack 11 .

[0035] For example, the test charging current value is set by dividing the current value of the battery pack 11 during charging by the number of secondary battery cells 111 connected in parallel in the battery pack 11 .

[0036] The test power supply circuit 19 controls the charging of the test secondary battery 190 using a test charging voltage value and a test charging current value.

[0037] The test power supply circuit 19 acquires the discharge conditions (discharge current value, discharge voltage value) of the battery pack 11 from the microcomputer 311. The test power supply circuit 19 sets the discharge voltage value and discharge current value of the multiple secondary battery cells 111 that make up the battery pack 11 to be the same as the test discharge voltage value and test discharge current value of the test secondary battery 190.

[0038] For example, the test discharge voltage value is set by dividing the voltage value across both ends of the battery pack 11 during discharge by the number of secondary battery cells 111 connected in series in the battery pack 11 .

[0039] For example, the test discharge current value is set by dividing the current value of the battery pack 11 during discharge by the number of secondary battery cells 111 connected in parallel in the battery pack 11 .

[0040] The test power supply circuit 19 controls the discharge of the test secondary battery 190 using a test discharge voltage value and a test discharge current value.

[0041] By performing such simulated charging and discharging, the secondary battery evaluation system of this embodiment can make the deterioration level of the test secondary battery 190 the same as the deterioration level of the secondary battery cells 111 that make up the battery pack 11.

[0042] (When Measuring SOC-OCV Data) When measuring SOC-OCV data, the test power supply circuit 19 temporarily stops simulating the charging and discharging of the battery pack 11 described above.

[0043] The test power supply circuit 19 stores the SOC-OCV measurement conditions in advance.

[0044] Prior to measuring the SOC-OCV, the test power supply circuit 19 discharges the test secondary battery 190 to a fully discharged state (SOC 0%). Then, intermittent charging for SOC-OCV measurement is performed, and SOC-OCV data (charge capacity and open circuit voltage) are measured up to a fully charged state (SOC 100%). Specifically, the test secondary battery 190 is charged from a fully discharged state (SOC 0%) at a predetermined current for a predetermined time (e.g., 1 minute at 1 C), followed by a relaxation time (e.g., 10 minutes) to allow the increased terminal voltage to settle. The terminal voltage after reaching equilibrium is measured as OCV data. This procedure is repeated until the battery is fully charged. This allows SOC-OCV data indicating how the OCV value changes with changes in SOC to be obtained.

[0045] The test power supply circuit 19 outputs the measured SOC-OCV data to the measurement data transmission unit 18. The measurement data transmission unit 18 transmits the SOC-OCV data to an external device for analyzing the degree of deterioration or the like.

[0046] As a result, the secondary battery evaluation system of this embodiment can acquire SOC-OCV data of the test secondary battery 190 without stopping the operation (charging and discharging) of the battery pack 11, and can perform OCV analysis of the test secondary battery 190.

[0047] In this case, as described above, the deterioration level of the test secondary battery 190 accurately simulates the deterioration level of the secondary battery cells 111 of the battery pack 11. Therefore, by performing an OCV analysis of the test secondary battery 190, it is possible to accurately perform an OCV analysis of the secondary battery cells 111 of the battery pack 11. As a result, the deterioration level of the secondary battery cells 111 of the battery pack 11 can be accurately evaluated.

[0048] When the measurement of the SOC-OCV data is completed, the test power supply circuit 19 acquires the state of charge of the battery pack 11 from the microcomputer 311 and resumes the above-described simulation of charging and discharging of the battery pack 11. Then, when it is time to measure the next SOC-OCV data, the test power supply circuit 19 measures the above-described SOC-OCV data. Thereafter, the simulation of charging and discharging of the battery pack 11 and the measurement of the SOC-OCV data are repeated.

[0049] As a result, the secondary battery evaluation system of this embodiment can continuously and accurately evaluate the degree of deterioration of the battery pack 11 (the secondary battery cells 111 of the battery pack 11).

[0050] Furthermore, in the above-described configuration, the test secondary battery 190 is disposed in the battery module 10, just like the battery pack 11. This makes the operating environment of the test secondary battery 190 similar to the operating environment (ambient temperature) of the battery pack 11. This improves the accuracy of simulating the deterioration level of the secondary battery cells 111 of the battery pack 11 using the test secondary battery 190. As a result, the secondary battery evaluation system of this embodiment can evaluate the deterioration level of the battery pack 11 (the secondary battery cells 111 of the battery pack 11) with even greater accuracy.

[0051] [Second Embodiment] A secondary battery evaluation system according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 4 is a functional block diagram showing an example of a secondary battery charge / discharge system including the secondary battery evaluation system according to the second embodiment of the present invention.

[0052] The secondary battery evaluation system according to the second embodiment differs from the secondary battery evaluation system according to the first embodiment in that it does not use the microcomputer 311, whereas the secondary battery evaluation system according to the first embodiment uses the microcomputer 311 of the storage battery PCS 31. Other configurations of the secondary battery evaluation system according to the second embodiment are the same as those of the secondary battery evaluation system according to the first embodiment, and a description of similar parts will be omitted.

[0053] The secondary battery evaluation system includes a battery module 10A. The battery module 10A differs from the battery module 10 according to the first embodiment in a test power supply circuit 19A. The other configuration of the battery module 10A is the same as that of the battery module 10, and a description of the same parts will be omitted.

[0054] The test power supply circuit 19A is connected to the output terminal of the current detection circuit 12 and the output terminal of the voltage detection circuit 13. The test power supply circuit 19A obtains the current value of the battery pack 11 directly from the current detection circuit 12. The test power supply circuit 19A obtains the voltage value across the battery pack 11 directly from the voltage detection circuit 13.

[0055] As a result, the secondary battery evaluation system of this embodiment can accurately measure SOC-OCV data for evaluating the degree of deterioration of the battery pack 11 (secondary battery cells 111 of the battery pack 11) using only the battery module 10A, without including the microcontroller 311 of the storage battery PCS 31.

[0056] [Third Embodiment] A secondary battery evaluation system according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 5 is a functional block diagram showing an example of the secondary battery evaluation system according to the third embodiment of the present invention.

[0057] The secondary battery evaluation system according to the third embodiment differs from the secondary battery evaluation system according to the second embodiment in that the test power supply circuit 19B, the test secondary battery 190, etc. are arranged in a location separate from the battery module 10B. Below, only the differences between the secondary battery evaluation system according to the third embodiment and the secondary battery evaluation system according to the second embodiment will be described, and descriptions of similar parts will be omitted.

[0058] (First location where battery module 10B is placed) The battery module 10B includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, and a temperature sensor 16. That is, the battery module 10B does not include a test power supply circuit 19B or a test secondary battery 190.

[0059] The temperature sensor 16 detects the ambient temperature of the battery pack 11 and outputs the detected temperature to the transmitter 17. The current detection circuit 12 outputs the current value of the battery pack 11 to the transmitter 17. The voltage detection circuit 13 outputs the voltage value of the battery pack 11 to the transmitter 17.

[0060] The transmitter 17 transmits the ambient temperature, the current value, and the voltage value to the receiver 194 .

[0061] (Second location where test secondary battery and test power supply circuit are placed) The receiving unit 194, the condition setting unit 195, the test power supply circuit 19B, the test secondary battery 190, and the measurement data transmitting unit 18 are placed in a location different from the battery module 10B. For example, these are placed in a testing site or the like where a user who performs OCV analysis is present.

[0062] The test power supply circuit 19B and the test secondary battery 190 are placed in a thermostatic oven THCH. A temperature regulator 199 is installed in the thermostatic oven THCH. The temperature regulator 199 adjusts the temperature of the thermostatic oven THCH.

[0063] The receiving unit 194 outputs the ambient temperature, the current value, and the voltage value to the condition setting unit 195. The condition setting unit 195 outputs the ambient temperature to the temperature regulator 199, and outputs the current value and the voltage value to the test power supply circuit 19B.

[0064] The temperature regulator 199 adjusts the temperature of the thermostatic bath THCH so that the temperature environment is the same as the received ambient temperature.

[0065] Based on the received current and voltage values, the test power supply circuit 19B simulates charging and discharging of the battery pack 11 for the test secondary battery 190. The test power supply circuit 19B also measures SOC-OCV data at predetermined timings.

[0066] As described above, the configuration of this embodiment allows OCV analysis and degradation evaluation to be performed without placing the test secondary battery 190 near the battery pack 11 to be evaluated. This makes it easy to entrust the evaluation to an OCV analysis expert in a remote location. For example, even without visiting a customer's site where an ESS is operated, a battery manufacturer can use a system with the test secondary battery 190 installed in-house to highly accurately evaluate the degradation of an ESS battery (battery pack 11) used at the customer's site.

[0067] Although the above description is written assuming a factory or the like, the secondary battery evaluation system of the present application can also be applied to the evaluation of secondary batteries (EV batteries) for EVs (electric vehicles) and the like that use electricity as a driving energy source.

[0068] Fig. 6 is a diagram showing an example of the schematic configuration of an EV to which a secondary battery evaluation system is applied. Fig. 7 is a functional block diagram showing an example of a battery module mounted on an EV. Fig. 8 is a functional block diagram showing an example of a test system configuration. Note that functional units having the same configuration as those in the above-described embodiments are denoted by the same reference numerals, and hereinafter, descriptions of parts with the same reference numerals will be omitted.

[0069] As shown in FIG. 6, the EV 90C includes an ECU 91, a DC-DC converter 92, an inverter 93, a drive motor 94, a charging port 95, a wireless device 96, and a battery module 10C.

[0070] As shown in FIG. 7, the battery module 10C includes a battery pack 11, a current detection circuit 12, a voltage detection circuit 13, a temperature sensor 16, and a microcomputer 911.

[0071] The ECU 91, the DCDC converter 92, the inverter 93, and the microcomputer 911 of the battery module 10C are connected to a CAN. The ECU 91 issues control commands to the DCDC converter 92, the inverter 93, and the battery module 10C via the CAN, and performs overall control of the EV 90C.

[0072] The DC-DC converter 92 is connected to the charging port 95 and to the inverter 93. The inverter 93 is connected to the drive motor 93.

[0073] The DC-DC converter 92 converts the DC power supplied from the charging port 95 into a charging voltage and a charging current for the battery pack 11 of the battery module 10C, and supplies the charging power for the battery pack 11 of the battery module 10C.

[0074] Furthermore, the DC-DC converter 92 converts the DC power charged in the battery pack 11 into a DC voltage for an inverter, and supplies the DC voltage to the inverter 93 .

[0075] The inverter 93 converts the DC current and DC voltage supplied through the DCDC converter 92 into a predetermined AC voltage and AC current, and supplies them to the drive motor 94 .

[0076] The wireless device 96 transmits the ambient temperature, current value, and voltage value acquired through the microcomputer 911 and the ECU 91 to a wireless communication unit 194C disposed in a thermostatic chamber THCH located at a different position from the EV 90C.

[0077] This makes it possible to measure SOC-OCV data using the thermostatic bath THCH as shown in the third embodiment.

[0078] <1> A battery pack comprising a plurality of secondary battery cells; a voltage detection circuit detecting a voltage value across the battery pack; a current detection circuit detecting a current value across the battery pack; a test secondary battery comprising at least one battery cell made of the same material as the secondary battery cells; and a power supply circuit controlling charging and discharging of the test secondary battery, wherein the power supply circuit sets a test charging voltage value and a test charging current value for the test secondary battery based on the voltage value across the both ends and the current value when the battery pack is being charged, and charges the test secondary battery with the test charging voltage value and the test charging current value; sets a test discharging voltage value and a test discharging current value for the test secondary battery based on the voltage value across the both ends and the current value when the battery pack is being discharged, and discharges the test secondary battery with the test discharging voltage value and the test discharging current value, thereby simulating charging and discharging of the battery pack, When measuring the SOC-OCV data, the test secondary battery is charged and discharged independently of the operation of the battery pack, and the SOC-OCV data of the test secondary battery is obtained.

[0079] <2> The secondary battery evaluation system according to <1>, wherein the test secondary battery is disposed in a battery module that houses the battery pack.

[0080] <3> The secondary battery evaluation system according to <1> or <2>, comprising: a temperature sensor that detects an ambient temperature of the battery pack; a transmitter that transmits the voltage value between both ends, the current value, and the ambient temperature; a receiver that receives the voltage value between both ends, the current value, and the ambient temperature of the battery pack from the transmitter; and a thermostatic bath, wherein the battery pack, the voltage detection circuit, the current detection circuit, the temperature sensor, and the transmitter are arranged in a first location; the test secondary battery, the power supply circuit, the receiver, and the thermostatic bath are arranged in a second location different from the first location; the test secondary battery is arranged in the thermostatic bath; and the thermostatic bath is controlled to reproduce the ambient temperature of the battery pack.

[0081] <4> The secondary battery evaluation system according to <3>, wherein the battery pack is a driving battery for an electric vehicle.

[0082] DESCRIPTION OF SYMBOLS 10, 10A, 10B, 10C: Battery module 11: Battery pack 12: Current detection circuit 13: Voltage detection circuit 16: Temperature sensor 17: Transmitter 18: Measurement data transmitter 19, 19A, 19B: Test power supply circuit 20: Solar panel 31: Storage battery PCS 32: Solar power PCS 40: System controller 50: Grid interconnection relay 60: Current sensor 90: Power system 90C: EV 91: ECU 92: DCDC converter 93: Inverter 94: Drive motor 95: Charging port 96: Wireless device 111: Secondary battery cell 190: Test secondary battery 194: Receiver 194C: Wireless communication unit 195: Condition setting unit 199: Temperature controller 311: Microcomputer 312: DCDC converter 911: Microcomputer THCH: Thermostatic chamber

Claims

1. A battery pack comprising a plurality of secondary battery cells; a voltage detection circuit detecting a voltage value across the battery pack; a current detection circuit detecting a current value across the battery pack; a test secondary battery comprising at least one battery cell manufactured from the same material as the secondary battery cells; and a power supply circuit controlling charging and discharging of the test secondary battery, wherein the power supply circuit sets a test charging voltage value and a test charging current value for the test secondary battery based on the voltage value across the two ends and the current value when the battery pack is charged, and charges the test secondary battery with the test charging voltage value and the test charging current value; sets a test discharging voltage value and a test discharging current value for the test secondary battery based on the voltage value across the two ends and the current value when the battery pack is discharged, and discharges the test secondary battery with the test discharging voltage value and the test discharging current value, thereby simulating charging and discharging of the battery pack, When measuring SOC-OCV data, charging and discharging of the test secondary battery is performed independently of driving of the battery pack, and the SOC-OCV data of the test secondary battery is obtained.

2. The secondary battery evaluation system according to claim 1, wherein the test secondary battery is disposed within a battery module that houses the battery pack.

3. A secondary battery evaluation system as described in claim 1, comprising: a temperature sensor for detecting the ambient temperature of the battery pack; a transmitting unit for transmitting the voltage value between both ends, the current value, and the ambient temperature; a receiving unit for receiving the voltage value between both ends, the current value, and the ambient temperature of the battery pack from the transmitting unit; and a thermostatic bath, wherein the battery pack, the voltage detection circuit, the current detection circuit, the temperature sensor, and the transmitting unit are disposed at a first location, the test secondary battery, the power supply circuit, the receiving unit, and the thermostatic bath are disposed at a second location different from the first location, the test secondary battery is disposed in the thermostatic bath, and the thermostatic bath is controlled to reproduce the ambient temperature of the battery pack.

4. The secondary battery evaluation system according to claim 3, wherein the battery pack is a driving battery for an electric vehicle.

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