Battery cell electrical performance evaluation method, device, electronic device and storage medium

Abstract

The embodiment of the present invention discloses a method, device, electronic device and storage medium for evaluating the electrical performance of a battery cell. The method includes determining the available energy of the battery cell to be tested at the end of its cycle life; determining the first energy efficiency of the battery cell to be tested; determining the corresponding relationship between the capacity and the discharge voltage of the battery cell to be tested; determining the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested; determining the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate and the remaining power percentage and the discharge voltage of the battery cell to be tested; determining the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage; evaluating the performance of the battery cell to be tested based on the above-determined available energy, the determined multiple efficiencies and the determined multiple corresponding relationships. The present invention tests and evaluates the electrical performance of the battery cell, confirms the quality of the electrical performance of the battery cell, improves the utilization rate of the battery cell and avoids waste of resources.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of battery cell performance evaluation, and in particular, to a battery cell performance evaluation method, device, electronic device, and storage medium. Background Art

[0002] As the application of lithium-ion batteries continues to develop, battery performance issues have received widespread attention, and comprehensive testing and evaluation of the performance of power battery cells is particularly important. At present, the electrical performance of lithium iron phosphate batteries is unknown at the end of the cycle.

[0003] The battery cell is the core part of the entire battery. Whether the battery cell works normally is directly related to the battery cell's electrical performance status. When the battery cell is cycled to the end of its life, the quality of its electrical performance status can also determine the quality of the battery cell produced. When the battery cell is about to reach the end of its cycle, whether the battery cell can continue to work normally, the existing technology test cannot evaluate the performance of the battery cell at the end of its cycle life, resulting in a large number of batteries that can still be used being eliminated and replaced, resulting in low battery cell utilization and serious waste of resources. Summary of the invention

[0004] The present invention provides a method, device, electronic device and storage medium for evaluating the electrical performance of a battery cell at the end of its cycle life, so as to judge whether the battery cell can continue to be used, thereby improving the utilization rate of the battery cell and reducing resource waste.

[0005] In a first aspect, an embodiment of the present invention provides a method for evaluating the electrical performance of a battery cell, the method comprising:

[0006] Determine the available energy of the battery cell under test at the end of its cycle life;

[0007] Determining a first energy efficiency of the battery cell to be tested;

[0008] Determine the corresponding relationship between the capacity and discharge voltage of the battery cell to be tested;

[0009] Determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested;

[0010] Determine the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate, and the remaining power percentage of the battery cell to be tested and the discharge voltage; determine the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage;

[0011] The performance of the battery cell to be tested is evaluated based on the available energy, the first energy efficiency, the corresponding relationship between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the corresponding relationship between the remaining power percentage and the discharge voltage, the corresponding relationship between the remaining power percentage and the charging open-circuit voltage, and the corresponding relationship between the remaining power percentage and the discharge open-circuit voltage.

[0012] Optionally, determining the available energy of the battery cell to be tested at the end of its cycle life includes:

[0013] A cyclic charge-discharge test is performed on the battery cell to be tested at a first set current to determine the available energy.

[0014] Optionally, determining the first energy efficiency of the battery cell includes:

[0015] With a second set current, the battery cell to be tested is charged to a first cutoff condition, then discharged to a first cutoff voltage, and finally charged to a second cutoff condition; wherein the discharge energy in the process of discharging from the first cutoff condition to the first cutoff voltage is W1, and the charging energy in the process of charging from the first cutoff voltage to the second cutoff condition is W2, and the first energy efficiency = W1 / W2.

[0016] Optionally, determining the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage includes:

[0017] The battery cell to be tested is discharged respectively under different percentages of remaining power and different temperatures, discharge data of the battery cell to be tested is obtained, and the corresponding relationship between the capacity and discharge voltage of the battery cell to be tested under different percentages of remaining power and different temperatures is determined according to the discharge data.

[0018] Optionally, determining the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested includes:

[0019] The battery cell to be tested is first charged to the second cut-off voltage with the third set current, then discharged to the third cut-off voltage with the third set current, then charged to the fourth cut-off voltage with the fourth set current, and then discharged to the fifth cut-off voltage with the third set current; wherein, the discharge capacity in the process of discharging from the second cut-off voltage to the third cut-off voltage is C0, the charging capacity in the process of charging from the third cut-off voltage to the fourth cut-off voltage is Q0, the discharge capacity in the process of discharging from the fourth cut-off voltage to the fifth voltage is C1, the discharge energy is Q1, the discharge capacity efficiency = C1 / C0, and the second energy efficiency = Q1 / Q0.

[0020] Optionally, determining the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate, and remaining power percentage of the battery cell to be tested and the discharge voltage includes:

[0021] Charging the battery cell to be tested with a fifth set current at a preset temperature;

[0022] The battery cell to be tested is discharged at a fifth set current at different temperatures to obtain the charge and discharge efficiency, capacity retention rate and energy retention rate of the battery cell to be tested at different temperatures and the corresponding relationship between the remaining power percentage and the discharge voltage.

[0023] Optionally, determining the correspondence between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage includes:

[0024] Charging the battery cell to be tested to a set remaining power percentage state with a sixth set current at different temperatures, recording the charging open circuit voltage after leaving it for a set time, and determining the corresponding relationship between the remaining power percentage and the charging open circuit voltage of the battery cell to be tested at different temperatures;

[0025] Determining the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage includes: discharging the battery cell to be tested to a set remaining power percentage state with a sixth set current under different temperature conditions, recording the discharge open circuit voltage after a set time, and determining the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage at different temperatures.

[0026] In a second aspect, an embodiment of the present invention further provides an electrical performance evaluation device for a battery cell, the device comprising:

[0027] An available energy determination module, used to determine the available energy of the battery cell to be tested at the end of its cycle life;

[0028] A first efficiency determination module, used to determine a first energy efficiency of the battery cell to be tested;

[0029] A first corresponding relationship determination module, used to determine the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage;

[0030] A second efficiency determination module, used to determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested;

[0031] A second corresponding relationship determination module is used to determine the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate and remaining power percentage of the battery cell to be tested and the discharge voltage;

[0032] A third corresponding relationship determination module is used to determine the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharging open circuit voltage;

[0033] An evaluation module is used to evaluate the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the corresponding relationship between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the corresponding relationship between the remaining power percentage and the discharge voltage, the corresponding relationship between the remaining power percentage and the charging open-circuit voltage, and the corresponding relationship between the remaining power percentage and the discharge open-circuit voltage.

[0034] In a third aspect, an embodiment of the present invention further provides an electronic device, including:

[0035] one or more processors;

[0036] A memory for storing one or more programs;

[0037] When the one or more programs are executed by one or more processors, the one or more processors implement the method for evaluating the electrical performance of a battery cell as described in an embodiment of the present invention.

[0038] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for evaluating the electrical performance of a battery cell as described in an embodiment of the present invention.

[0039] The technical solution of this embodiment evaluates the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the correspondence between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the correspondence between the remaining power percentage and the discharge voltage, the correspondence between the remaining power percentage and the charging open circuit voltage, and the correspondence between the remaining power percentage and the discharge open circuit voltage. The series of tests carried out in the evaluation provide strong evidence for the electrical performance of the EOL state battery cells. By evaluating the electrical performance of the EOL state battery cells, it can be determined whether the battery cells can provide normal working capabilities, which solves the problem that the prior art tests cannot evaluate the performance of the battery cells at the end of the cycle life, resulting in a large number of battery cells that can still be used being eliminated and replaced, resulting in low battery cell utilization and serious waste of resources. The technical solution of this embodiment can evaluate the degree of electrical performance of the battery cells at the end of the cycle life, determine whether the battery cells can continue to be used, and thus improve the utilization rate of the battery cells and reduce resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flow chart of a method for evaluating the electrical performance of a battery cell provided in Embodiment 1 of the present invention;

[0041] Figure 2 is a capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0042] Figure 3 is another capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0043] Figure 4 is another capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0044] Figure 5 is another capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0045] Figure 6 is another capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0046] Figure 7 is another capacity-voltage curve diagram provided by the first embodiment of the present invention;

[0047] Figure 8 A graph showing the percentage of remaining power and the discharge voltage provided in the first embodiment of the present invention;

[0048] Fig. 9 This is another graph of remaining power percentage and discharge voltage provided in the first embodiment of the present invention;

[0049] Fig.10 This is another graph of remaining power percentage and discharge voltage provided in the first embodiment of the present invention;

[0050] Fig.11 This is another graph of remaining power percentage and discharge voltage provided in the first embodiment of the present invention;

[0051] Fig.12 This is another graph of remaining power percentage and discharge voltage provided in the first embodiment of the present invention;

[0052] Fig.13 is a curve diagram of the remaining power percentage and the charging open circuit voltage provided by the first embodiment of the present invention;

[0053] Fig.14 is another curve diagram of the remaining power percentage and the charging open circuit voltage provided by the first embodiment of the present invention;

[0054] Fig.15 is another curve diagram of the remaining power percentage and the charging open circuit voltage provided by the first embodiment of the present invention;

[0055] Fig.16 is a curve diagram of the remaining power percentage and the discharge open circuit voltage provided by the first embodiment of the present invention;

[0056] Fig.17 is another curve diagram of the remaining power percentage and the discharge open circuit voltage provided in the first embodiment of the present invention;

[0057] Fig.18 is another curve diagram of the remaining power percentage and the discharge open circuit voltage provided in the first embodiment of the present invention;

[0058] Fig.19 It is a structural schematic diagram of an electric performance evaluation device for a battery cell provided in a second embodiment of the present invention;

[0059] Fig. 20 It is a structural schematic diagram of an electronic device provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0061] Embodiment 1

[0062] Figure 1 This is a flow chart of a method for evaluating the electrical performance of a battery cell provided in the first embodiment of the present invention. This embodiment is applicable to the case of evaluating the performance of a battery cell to be tested. The method can be performed by the device for evaluating the electrical performance of a battery cell provided in the embodiment of the present invention. The device can be implemented in software and / or hardware and can generally be integrated in an electronic device. Figure 1 , the method specifically comprises the following steps:

[0063] S110: Determine the available energy of the battery cell to be tested at the end of its cycle life.

[0064] The voltage, current, internal resistance and other tests may be performed on the battery cell to be tested at the end of its cycle life (End Of Life, EOL) state, and the available energy of the battery cell to be tested may be determined through the above tests.

[0065] Optionally, determining the available energy of the battery cell to be tested that is at the end of its cycle life includes: performing a cyclic charge and discharge test on the battery cell to be tested at a first set current to determine the available energy.

[0066] Among them, the first set current can be 1C current, and C is the nominal capacity of the battery (under certain discharge conditions, the minimum amount of electricity should be discharged). Specifically, the available energy of the battery cell to be tested can be tested at different temperatures. For example, the test temperature can be 25℃ and 45℃. Under the conditions of 25℃±2℃ and 45℃±2℃, the battery cell to be tested is charged to the cut-off condition with 1C constant current and constant voltage, and then the battery cell to be tested is discharged to the cut-off voltage with 1C. Among them, the cut-off condition means that the cut-off voltage can be 3.65V and the cut-off current can be 0.05C.

[0067] In order to improve the accuracy of the available energy of the battery cell to be tested, the battery cell to be tested in the EOL state can be subjected to multiple cycles of charge and discharge tests to determine the available energy of the battery cell to be tested after multiple cycles of charge and discharge. The available energy can include discharge capacity and discharge energy. The available energy of the battery cell to be tested in the EOL state can be determined by comparing the discharge capacity with the set discharge capacity threshold or the discharge energy with the set discharge energy threshold to determine whether the available energy of the battery cell to be tested meets the requirements. The state of health (SOH) of the battery cell refers to the percentage of the current capacity of the battery cell to be tested to the factory capacity. Generally, the end of the cycle life of the battery cell is defined as 80% SOH, but in some special cases, there will be a demand for 70% SOH. Therefore, in this embodiment, the battery cell to be tested at the end of the cycle life can be a battery cell of 70% SOH-80% SOH, and this embodiment takes the battery cells to be tested in the two states of 70% SOH and 80% SOH as examples for testing. The data of the battery cells to be tested of 80% SOH and 70% SOH are specifically shown in Table 1.

[0068] Table 1

[0069]

[0070] Table 1 shows the discharge capacity and energy data of the battery cells that have reached the end of their cycle life. It can be seen from Table 1 that when the discharge energy of the battery cell to be tested at 80% SOH is ≥588.8Wh, and the discharge energy of the battery cell to be tested at 70% SOH is ≥515.2Wh, it indicates that the available energy of the battery cell to be tested meets the requirements at the EOL state. When the discharge capacity of the battery cell to be tested at 80% SOH is greater than or equal to the first set discharge capacity threshold, and the discharge capacity of the battery cell to be tested at 70% SOH is greater than or equal to the second set discharge capacity threshold, it indicates that the available energy of the battery cell to be tested meets the requirements at the EOL state. It should be noted that the first set discharge capacity threshold and the second set discharge capacity threshold can be set according to actual needs.

[0071] S120: Determine a first energy efficiency of the battery cell to be tested.

[0072] The first energy efficiency refers to the percentage of discharge energy to charge energy in the charge and discharge cycle of the battery cell under test under given conditions. The battery cell under test is charged and discharged to determine the first energy efficiency of the battery cell under test during the charge and discharge process.

[0073] Optionally, determining the first energy efficiency of the battery cell includes: charging the battery cell to be tested to a first cutoff condition with a second set current, then discharging it to a first cutoff voltage, and finally charging it to a second cutoff condition; wherein, the discharge energy in the process of discharging from the first cutoff condition to the first cutoff voltage is W1, and the charging energy in the process of charging from the first cutoff voltage to the second cutoff condition is W2, and the first energy efficiency = W1 / W2.

[0074] Among them, the second set current can be 1C current, the first cut-off condition can be that the voltage reaches 3.65V, the first cut-off voltage can be 2.5V, and the second cut-off condition can be that the voltage reaches 3.65V. Specifically, this embodiment is tested at 25℃±2℃, and the 1# and 2# groups of cells to be tested are charged to the first cut-off condition in a 1C constant current and constant voltage manner, and then the 1# and 2# groups of cells to be tested are discharged to the first cut-off voltage in a 0.5C manner, and finally the 1# and 2# groups of cells to be tested are charged to the second cut-off condition in a 1C constant current manner, and the first energy efficiency during the charge and discharge test of the cells to be tested is calculated. Exemplarily, the tests of the two groups of cells to be tested are shown in Table 2.

[0075] Table 2

[0076] serial number temperature SOH 0.5C discharge energy W1 / Wh 1C charging energy W2 / Wh First energy efficiency 1# 25℃ 80％ 595.211 626.229 95.05％ 2# 25℃ 80％ 593.788 620.05 95.76％

[0077] It can be seen from Table 2 that when the first energy efficiency is greater than 93%, it meets the requirements for the battery cell electrical performance evaluation. The larger the value of the first energy efficiency, the smaller the proportion of energy consumed by the battery cell during the charging and discharging process, and the better the performance of the battery cell.

[0078] S130, determining the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage.

[0079] Optionally, determining the correspondence between the capacity of the battery cell to be tested and the discharge voltage includes: discharging the battery cell to be tested under different remaining power percentages and different temperatures, respectively, obtaining discharge data of the battery cell to be tested, and determining the correspondence between the capacity of the battery cell to be tested and the discharge voltage under different remaining power percentages and different temperatures based on the discharge data.

[0080] Among them, the remaining power percentage (State of charge, SOC) refers to the percentage of the current remaining power of the battery cell to be tested to the power of the battery cell to be tested when it is fully charged, which is generally less than 30%. The battery cell to be tested is subjected to constant power continuous discharge, constant current continuous discharge and constant current pulse discharge under different remaining power percentages and different temperatures, and the discharge data is obtained. For example, the SOC of constant power continuous discharge is lower than that of pulse. Constant power continuous discharge and constant current continuous discharge can be 20% SOC, and constant current pulse discharge can be 30% SOC. A capacity-voltage curve is made based on the discharge data. The capacity-voltage curve reflects the corresponding relationship between the capacity and discharge voltage of the battery cell to be tested under different remaining power percentages and different temperatures.

[0081] Figure 2-7 is a capacity-voltage curve diagram under different conditions provided in Example 1 of the present invention, referring to Figure 2-7 , Figure 2-7The vertical axis represents voltage, and the horizontal axis represents capacity. For example, at 5°C and 20% SOC, the 1# and 2# groups of cells to be tested are discharged in a 1C constant current continuous discharge mode, and the obtained capacity-voltage curve is as follows: Figure 2 At -5℃, 30% SOC, the 1# and 2# groups of cells to be tested were discharged in 2C constant current pulse discharge mode, and the obtained capacity-voltage curve is shown in Figure 3 At 20°C and 30% SOC, the 1# and 2# groups of cells to be tested were discharged in a constant power continuous discharge mode. The obtained capacity-voltage curve is shown in Figure 4 At 60°C and 20% SOC, the 1# and 2# groups of cells to be tested were discharged in a 1C constant current continuous discharge mode. The obtained capacity-voltage curve is shown in Figure 5 At 60°C and 30% SOC, the 1# and 2# groups of cells to be tested were discharged using a 2C constant current pulse discharge method. The resulting capacity-voltage curve is shown in Figure 6 At 60°C and 30% SOC, the 1# and 2# groups of cells to be tested were discharged in a constant power continuous discharge mode. The obtained capacity-voltage curve is shown in Figure 7 If the battery cell to be tested can complete the discharge test process and the capacity-voltage curve trend is normal, it indicates that the electrical performance of the battery cell to be tested is normal.

[0082] S140, determining the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested.

[0083] Optionally, determining the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested includes: first charging the battery cell to be tested to a second cut-off voltage with a third set current, then discharging to a third cut-off voltage with the third set current, then charging to a fourth cut-off voltage with a fourth set current, and then discharging to a fifth cut-off voltage with the third set current; wherein, the discharge capacity during the process of discharging from the second cut-off voltage to the third cut-off voltage is C0, the charging capacity during the process of charging from the third cut-off voltage to the fourth cut-off voltage is Q0, the discharge capacity during the process of discharging from the fourth cut-off voltage to the fifth voltage is C1, the discharge energy is Q1, the discharge capacity efficiency = C1 / C0, and the second energy efficiency = Q1 / Q0.

[0084] Among them, the third set current can be 1C current; the second cut-off voltage can be 3.65V; the third cut-off voltage can be 2.5V; the fourth set current can be 2C current; the fourth cut-off voltage can be 3.65V; the fifth cut-off voltage can be 2.5V. Specifically, this embodiment is tested at 25℃±2℃, and the 1# and 2# groups of cells to be tested are charged to the second cut-off voltage in a 1C constant current and constant voltage mode, and then the 1# and 2# groups of cells to be tested are discharged to the third cut-off voltage in a 1C mode, and then the 1# and 2# groups of cells to be tested are charged to the fourth cut-off voltage in a 2C mode, and then the 1# and 2# groups of cells to be tested are discharged to the fifth cut-off voltage in a 2C mode. Finally, the discharge capacity efficiency and the second energy efficiency of the cells to be tested are calculated, and the data obtained from the test of the cells to be tested and the data obtained from the calculation are specifically shown in Table 3.

[0085] Table 3

[0086] serial number C0 / Ah C1 / Ah Q0 / Wh Q1 / Wh Discharge capacity efficiency Second energy efficiency 1# 184.649 179.6 619.935 563.94 96.88％ 90.97％ 2# 185.378 177.393 610.33 557.609 96.07％ 91.36％

[0087] It can be seen from Table 3 that when the discharge capacity efficiency and the second energy efficiency are both greater than 90%, the electrical performance of the battery cell to be tested meets the requirements.

[0088] S150, determining the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate, and remaining power percentage of the battery cell to be tested and the discharge voltage; determining the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage.

[0089] Optionally, determining the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate and the percentage of remaining power and the discharge voltage of the battery cell to be tested includes: charging the battery cell to be tested with a fifth set current at a preset temperature; discharging the battery cell to be tested with the fifth set current at different temperatures, respectively, to obtain the corresponding relationship between the charge and discharge efficiency, capacity retention rate and energy retention rate of the battery cell to be tested at different temperatures, and the percentage of remaining power and the discharge voltage.

[0090] Wherein, the fifth set current can be a 1C current. Exemplarily, at a preset temperature of 25°C, the two groups of cells to be tested, 1# and 2# in the EOL state, are charged with a 1C constant current and constant voltage, and charged to a cut-off voltage of 3.65V and a cut-off current of 0.05C. The two groups of cells to be tested, 1# and 2# in the EOL state, are discharged with a 1C constant current at 55°C, 45°C, 5°C, 0°C and -20°C. The charge and discharge efficiency, capacity retention rate and energy retention rate of the cells to be tested are calculated based on the test data, and compared with the test data of the cells to be tested at the beginning of the cycle life (Begin Of Life, BOL) state. For specific data, see Table 4. Wherein, charge and discharge efficiency = discharge capacity / charge capacity; capacity retention rate = discharge capacity / rated capacity; energy retention rate = discharge energy / rated energy.

[0091] Table 4

[0092]

[0093] It can be seen from Table 4 that when the charge and discharge efficiency of the battery cell to be tested is greater than or equal to the first preset threshold, the capacity retention rate is greater than or equal to the second preset threshold, and the energy retention rate is greater than or equal to the third preset threshold, it indicates that the discharge performance of the battery cell to be tested is normal.

[0094] Figure 8-12 They are the remaining power percentage and discharge voltage curves of the tested battery cell during 1C constant current discharge at 55°C, 45°C, 25°C, 0°C and -20°C provided in the first embodiment of the present invention, and refer to Figure 8-12 , Figure 8-12 The vertical axis represents voltage, and the horizontal axis represents the set SOC. For example, at 55°C, the two groups of cells to be tested, 1# and 2#, are discharged at a constant current of 1C to obtain the test data of the cells to be tested in the EOL state. The test data are compared with the test data of the cells to be tested in the BOL state. The remaining power percentage and discharge voltage curve of the cells to be tested in the EOL state 1# and 2# and the BOL state are plotted on the same graph. The curve is as follows: Figure 8 The remaining power percentage and discharge voltage curve of the tested battery cells in EOL state 1# and 2# and BOL state at 45°C are shown in the figure below. Fig. 9 As shown; the remaining power percentage and discharge voltage curve of the tested battery cells in EOL state 1# and 2# and BOL state at 25℃ are as follows Fig.10 As shown; the remaining power percentage and discharge voltage curve of the tested battery cells in EOL state 1# and 2# and BOL state at 0℃ are as follows Fig.11 As shown; the remaining power percentage and discharge voltage curve of the tested battery cells in EOL state 1# and 2# and BOL state at -20℃ are as follows Fig.12 As shown. Figure 8-12It can be seen that the remaining power percentage and discharge voltage curve trends of the tested battery cell in the BOL state and the EOL state are not much different, indicating that the electrical performance of the tested battery cell is normal.

[0095] It should be noted that if the electrical performance of the battery to be tested is normal, there should be no obvious difference in the test data and the curve trend should be consistent. Since the capacity of the battery to be tested in the BOL state is different from that in the BOL state, using the remaining power percentage and the discharge voltage curve instead of the capacity-voltage curve can more intuitively show the difference in discharge between the battery to be tested in the BOL state and the EOL state.

[0096] Optionally, determining the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage includes:

[0097] At different temperatures, the battery cell to be tested is charged with a sixth set current to a set remaining power percentage state, and after a set time, the charging open circuit voltage is recorded to determine the corresponding relationship between the remaining power percentage and the charging open circuit voltage of the battery cell to be tested at different temperatures;

[0098] Determining the correspondence between the remaining power percentage and the discharge open circuit voltage of the battery cell to be tested includes: discharging the battery cell to be tested to a set remaining power percentage state with a sixth set current under different temperature conditions, recording the discharge open circuit voltage after leaving it for a set time, and determining the correspondence between the remaining power percentage and the discharge open circuit voltage of the battery cell to be tested at different temperatures.

[0099] Among them, the sixth set current can be a 0.1C current. Specifically, at 45°C, 25°C and 0°C, the two groups of cells to be tested in the EOL state, 1# and 2#, are charged to the set remaining power percentage state with a 0.1C constant current and constant voltage, and the charging open circuit voltage is recorded after being left for 1 hour, and the remaining power percentage and charging open circuit voltage curves of the cells to be tested at 45°C, 25°C and 0°C are plotted respectively, and then compared with the remaining power percentage and charging open circuit voltage curve trends of the cells to be tested in the BOL state. Figure 13-15 They are curves of the remaining power percentage and the charging open circuit voltage at 45°C, 25°C and 0°C provided in the first embodiment of the present invention, and refer to Figure 13-15 , Figure 13-15 The vertical axis represents the charging open circuit voltage, and the horizontal axis represents the set SOC. Figure 13-15 It can be seen that the remaining power percentage of the tested battery cell in the BOL state and the EOL state is consistent with the trend of the charging open circuit voltage curve, indicating that the electrical performance of the tested battery cell is normal.

[0100] At 45℃, 25℃ and 0℃, the two groups of test cells 1# and 2# in EOL state were discharged to the set remaining power percentage state with 0.1C constant current and constant voltage, and the discharge open circuit voltage was recorded after 1h. The remaining power percentage and discharge open circuit voltage curves of the test cells at 45℃, 25℃ and 0℃ were plotted respectively, and then compared with the remaining power percentage and discharge open circuit voltage curve trends of the test cells in BOL state. Figure 16-18 They are curves of the remaining power percentage and the discharge open circuit voltage at 45°C, 25°C and 0°C provided in the first embodiment of the present invention, and refer to Figure 16-18 , Figure 16-18 The vertical axis represents the discharge open circuit voltage, and the horizontal axis represents the set SOC. Figure 16-18 It can be seen that the remaining power percentage of the tested cell in the BOL state and the EOL state is consistent with the trend of the discharge open circuit voltage curve, indicating that the electrical performance of the tested cell is normal.

[0101] S160, evaluating the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the correspondence between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the correspondence between the remaining power percentage and the discharge voltage, the correspondence between the remaining power percentage and the charge open circuit voltage, and the correspondence between the remaining power percentage and the discharge open circuit voltage.

[0102] Specifically, the performance of the battery cell to be tested is evaluated as follows: when the discharge energy of the battery cell to be tested at 80% SOH is ≥588.8Wh, and the discharge energy of the battery cell to be tested at 70% SOH is ≥515.2Wh, it indicates that the available energy of the battery cell to be tested meets the requirements in the EOL state. When the discharge capacity of the battery cell to be tested at 80% SOH is greater than or equal to the first set discharge capacity threshold, and the discharge capacity of the battery cell to be tested at 70% SOH is greater than or equal to the second set discharge capacity threshold, it indicates that the available energy of the battery cell to be tested meets the requirements in the EOL state. The charge and discharge efficiency of the battery cell to be tested is greater than or equal to the first preset threshold, the capacity retention rate is greater than or equal to the second preset threshold, and the energy retention rate is greater than or equal to the third preset threshold, indicating that the discharge performance of the battery cell to be tested is normal. If the battery cell to be tested can complete the discharge process under different temperature conditions and under the set SOC state, and there is no abnormality in the trend of the capacity and discharge voltage curve, it indicates that the discharge performance of the battery cell to be tested is normal. When the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested are both greater than 90%, it indicates that the charging performance of the battery cell to be tested meets the requirements. If the remaining power percentage of the BOL state and the EOL state is not much different from the discharge voltage curve trend, it indicates that the electrical performance of the battery to be tested is normal. If the remaining power percentage of the BOL state and the EOL state of the battery to be tested is consistent with the charge open circuit voltage curve trend, it indicates that the electrical performance of the battery to be tested is normal. If the remaining power percentage of the BOL state and the EOL state of the battery to be tested is consistent with the discharge open circuit voltage curve trend, it indicates that the electrical performance of the battery to be tested is normal.

[0103] By testing the electrical performance of the battery cell at the end of the cycle and analyzing and evaluating the test results, it is used to confirm whether the electrical performance of the battery cell at the EOL state can meet the technical requirements. The test in this embodiment can test the discharge capacity of the battery cell and can also evaluate the electrical performance status of the battery cell. If all tests are qualified, it means that the battery cell at the EOL state can provide normal working capacity. Evaluating the battery cell status can effectively guide technicians to maintain the battery cell, determine whether the remaining available capacity of the battery cell can meet the total power demand, and determine when each single battery cell and battery cell group needs to be replaced and repaired.

[0104] The technical solution of this embodiment evaluates the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the correspondence between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the correspondence between the remaining power percentage and the discharge voltage, the correspondence between the remaining power percentage and the charging open circuit voltage, and the correspondence between the remaining power percentage and the discharge open circuit voltage. The series of tests carried out in the evaluation provide strong evidence for the electrical performance of the EOL state battery cells. By evaluating the electrical performance of the EOL state battery cells, it can be determined whether the battery cells can provide normal working capabilities, which solves the problem that the prior art tests cannot evaluate the performance of the battery cells at the end of the cycle life, resulting in a large number of battery cells that can still be used being eliminated and replaced, resulting in low battery cell utilization and serious waste of resources. The technical solution of this embodiment can evaluate the degree of electrical performance of the battery cells at the end of the cycle life, determine whether the battery cells can continue to be used, and thus improve the utilization rate of the battery cells and reduce resource waste.

[0105] Embodiment 2

[0106] Fig.19 is a schematic diagram of the structure of an electric performance evaluation device for a battery cell provided in the second embodiment of the present invention, with reference to Fig.19 , the device can be configured in an electronic device, and the device includes:

[0107] The available energy determination module 201 is used to determine the available energy of the battery cell to be tested at the end of its cycle life;

[0108] A first efficiency determination module 202, used to determine a first energy efficiency of the battery cell to be tested;

[0109] A first corresponding relationship determination module 203, used to determine the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage;

[0110] A second efficiency determination module 204, used to determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested;

[0111] The second corresponding relationship determination module 205 is used to determine the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate and remaining power percentage of the battery cell to be tested and the discharge voltage;

[0112] The third corresponding relationship determination module 206 is used to determine the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharging open circuit voltage;

[0113] The evaluation module 207 is used to evaluate the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the correspondence between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the correspondence between the remaining power percentage and the discharge voltage, the correspondence between the remaining power percentage and the charging open-circuit voltage, and the correspondence between the remaining power percentage and the discharge open-circuit voltage.

[0114] The above-mentioned battery cell electrical performance evaluation device can execute the battery cell electrical performance evaluation method provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the battery cell electrical performance evaluation method.

[0115] Continue to refer Fig.19 Optionally, the available energy determination module 201 is used to determine the available energy of the battery cell to be tested at the end of its cycle life, including: performing a cyclic charge and discharge test on the battery cell to be tested with a first set current to determine the available energy.

[0116] Continue to refer Fig.19 Optionally, the first efficiency determination module 202 is used to determine the first energy efficiency of the battery cell to be tested, including: charging the battery cell to be tested to a first cut-off condition with a second set current, then discharging it to a first cut-off voltage, and finally charging it to a second cut-off condition; wherein, the discharge energy in the process of discharging from the first cut-off condition to the first cut-off voltage is W1, and the charging energy in the process of charging from the first cut-off voltage to the second cut-off condition is W2, and the first energy efficiency = W1 / W2.

[0117] Continue to refer Fig.19 Optionally, the first correspondence determination module 203 is used to determine the correspondence between the capacity of the battery cell to be tested and the discharge voltage, including: discharging the battery cell to be tested under different remaining power percentages and different temperatures, obtaining the discharge data of the battery cell to be tested and determining the correspondence between the capacity of the battery cell to be tested and the discharge voltage under different remaining power percentages and different temperatures according to the discharge data.

[0118] Continue to refer Fig.19 Optionally, the second efficiency determination module 204 is used to determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested, including: charging the battery cell to be tested to the second cut-off voltage with a third set current, then discharging to the third cut-off voltage with the third set current, then charging to the fourth cut-off voltage with a fourth set current, and then discharging to the fifth cut-off voltage with the third set current; wherein the discharge capacity in the process of discharging from the second cut-off voltage to the third cut-off voltage is C0, the charge capacity in the process of charging from the third cut-off voltage to the fourth cut-off voltage is Q0, the discharge capacity in the process of discharging from the fourth cut-off voltage to the fifth voltage is C1, the discharge energy is Q1, the discharge capacity efficiency = C1 / C0, and the second energy efficiency = Q1 / Q0.

[0119] Continue to refer Fig.19 Optionally, the second correspondence determination module 205 is used to determine the correspondence between the charge and discharge efficiency, capacity retention rate, energy retention rate and the percentage of remaining power and the discharge voltage of the battery cell to be tested, including: charging the battery cell to be tested with a fifth set current at a preset temperature; discharging the battery cell to be tested with the fifth set current at different temperatures, respectively, to obtain the charge and discharge efficiency, capacity retention rate and energy retention rate of the battery cell to be tested at different temperatures, and the correspondence between the percentage of remaining power and the discharge voltage.

[0120] Continue to refer Fig.19 Optionally, the third correspondence determination module 206 is used to determine the correspondence between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, including: charging the battery cell to be tested to a set remaining power percentage state with a sixth set current at different temperatures, recording the charging open circuit voltage after a set time, and determining the correspondence between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage at different temperatures;

[0121] The third correspondence determination module 206 is also used to determine the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage, including: discharging the battery cell to be tested to a set remaining power percentage state with a sixth set current under different temperature conditions, recording the discharge open circuit voltage after leaving it for a set time, and determining the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage at different temperatures.

[0122] Embodiment 3

[0123] Fig. 20 It is a structural schematic diagram of an electronic device provided in Embodiment 3 of the present invention. Fig. 20 A block diagram of an exemplary electronic device 12 for implementing embodiments of the present invention is shown. Fig. 20 The electronic device 12 shown is only an example and does not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0124] like Fig. 20 As shown, the electronic device 12 is in the form of a general electronic device. The components of the electronic device 12 may include, but are not limited to: one or more processors 16, a memory 28, and a bus 18 connecting different system components (including the memory 28 and the processor 16). The processor 16 includes, but is not limited to, an AI processor.

[0125] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures. By way of example, these architectures include, but are not limited to, an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MAC) bus, an Enhanced ISA bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnect (PCI) bus.

[0126] The electronic device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the electronic device 12, including volatile and non-volatile media, removable and non-removable media.

[0127] The memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The electronic device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be used to read and write non-removable, non-volatile magnetic media ( Fig. 20 not shown, usually called a "hard drive"). Although Fig. 20 Not shown in the figure, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, a DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the various embodiments of the present invention.

[0128] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in the memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. The program modules 42 generally perform the functions and / or methods of the embodiments described herein.

[0129] The electronic device 12 may also communicate with one or more external devices 14 (e.g., keyboards, pointing devices, displays 24, etc.), may communicate with one or more devices that enable a user to interact with the electronic device 12, and / or may communicate with any device that enables the electronic device 12 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). Such communication may be performed via an input / output (I / O) interface 22. Furthermore, the electronic device 12 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 20. As shown, the network adapter 20 communicates with other modules of the electronic device 12 via the bus 18. It should be understood that although Fig. 20 Not shown, other hardware and / or software modules may be used in conjunction with the electronic device 12, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0130] The processor 16 of the electronic device 12 executes various functional applications and data processing by running the programs stored in the memory 28, such as implementing the electric performance evaluation method of the battery cell provided in the embodiment of the present invention.

[0131] Embodiment 4

[0132] The fourth embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method for evaluating the electrical performance of a battery cell provided in the embodiment of the present invention is implemented.

[0133] The computer storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0134] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0135] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0136] Computer program code for performing the operations of the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, Ruby, Go, conventional procedural programming languages ​​such as "C" or similar programming languages, and computer languages ​​of AI algorithms. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0137] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for evaluating the electrical performance of a battery cell, characterized in that: include: Determine the available energy of the battery cell under test at the end of its cycle life; Determining a first energy efficiency of the battery cell to be tested; Determine the corresponding relationship between the capacity and discharge voltage of the battery cell to be tested; Determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested; Determine the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate, and remaining power percentage of the battery cell to be tested and the discharge voltage; Determine the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharging open circuit voltage; Evaluate the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the corresponding relationship between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the corresponding relationship between the remaining power percentage and the discharge voltage, the corresponding relationship between the remaining power percentage and the charge open circuit voltage, and the corresponding relationship between the remaining power percentage and the discharge open circuit voltage; Determining the first energy efficiency of the battery cell includes: With a second set current, the battery cell to be tested is charged to a first cut-off condition, then discharged to a first cut-off voltage, and finally charged to a second cut-off condition; wherein the discharge energy in the process of discharging from the first cut-off condition to the first cut-off voltage is W1, the charging energy in the process of charging from the first cut-off voltage to the second cut-off condition is W2, and the first energy efficiency = W1 / W2; Determining the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested comprises: The battery cell to be tested is first charged to the second cut-off voltage with the third set current, then discharged to the third cut-off voltage with the third set current, then charged to the fourth cut-off voltage with the fourth set current, and then discharged to the fifth cut-off voltage with the third set current; wherein, the discharge capacity in the process of discharging from the second cut-off voltage to the third cut-off voltage is C0, the charging capacity in the process of charging from the third cut-off voltage to the fourth cut-off voltage is Q0, the discharge capacity in the process of discharging from the fourth cut-off voltage to the fifth voltage is C1, the discharge energy is Q1, the discharge capacity efficiency = C1 / C0, and the second energy efficiency = Q1 / Q0.

2. The method according to claim 1, characterized in that: Determining the available energy of the battery cell to be tested at the end of its cycle life includes: A cyclic charge-discharge test is performed on the battery cell to be tested at a first set current to determine the available energy.

3. The method according to claim 1, characterized in that Determining the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage includes: The battery cell to be tested is discharged respectively under different percentages of remaining power and different temperatures, discharge data of the battery cell to be tested is obtained, and the corresponding relationship between the capacity and discharge voltage of the battery cell to be tested under different percentages of remaining power and different temperatures is determined according to the discharge data.

4. The method according to claim 1, characterized in that: Determining the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate, and remaining power percentage of the battery cell to be tested and the discharge voltage includes: Charging the battery cell to be tested with a fifth set current at a preset temperature; The battery cell to be tested is discharged at a fifth set current at different temperatures to obtain the charge and discharge efficiency, capacity retention rate and energy retention rate of the battery cell to be tested at different temperatures and the corresponding relationship between the remaining power percentage and the discharge voltage.

5. The method according to claim 1, characterized in that: Determining the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage includes: Charging the battery cell to be tested to a set remaining power percentage state with a sixth set current at different temperatures, recording the charging open circuit voltage after leaving it for a set time, and determining the corresponding relationship between the remaining power percentage and the charging open circuit voltage of the battery cell to be tested at different temperatures; Determining the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage includes: discharging the battery cell to be tested to a set remaining power percentage state with a sixth set current under different temperature conditions, recording the discharge open circuit voltage after a set time, and determining the correspondence between the remaining power percentage of the battery cell to be tested and the discharge open circuit voltage at different temperatures.

6. An electrical performance evaluation device for a battery cell, characterized in that: include: An available energy determination module, used to determine the available energy of the battery cell to be tested at the end of its cycle life; A first efficiency determination module, used to determine a first energy efficiency of the battery cell to be tested; A first corresponding relationship determination module, used to determine the corresponding relationship between the capacity of the battery cell to be tested and the discharge voltage; A second efficiency determination module, used to determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested; A second corresponding relationship determination module is used to determine the corresponding relationship between the charge and discharge efficiency, capacity retention rate, energy retention rate and remaining power percentage of the battery cell to be tested and the discharge voltage; A third corresponding relationship determination module is used to determine the corresponding relationship between the remaining power percentage of the battery cell to be tested and the charging open circuit voltage, and the corresponding relationship between the remaining power percentage of the battery cell to be tested and the discharging open circuit voltage; An evaluation module, used to evaluate the performance of the battery cell to be tested according to the available energy, the first energy efficiency, the corresponding relationship between the capacity and the discharge voltage, the discharge capacity efficiency, the second energy efficiency, the charge and discharge efficiency, the capacity retention rate, the energy retention rate, the corresponding relationship between the remaining power percentage and the discharge voltage, the corresponding relationship between the remaining power percentage and the charge open circuit voltage, and the corresponding relationship between the remaining power percentage and the discharge open circuit voltage; The first efficiency determination module is used to determine the first energy efficiency of the battery cell to be tested, including: charging the battery cell to be tested to a first cutoff condition with a second set current, then discharging it to a first cutoff voltage, and finally charging it to a second cutoff condition; wherein the discharge energy in the process of discharging from the first cutoff condition to the first cutoff voltage is W1, and the charging energy in the process of charging from the first cutoff voltage to the second cutoff condition is W2, and the first energy efficiency = W1 / W2; The second efficiency determination module is used to determine the discharge capacity efficiency and the second energy efficiency of the battery cell to be tested, including: first charging the battery cell to be tested to a second cut-off voltage with a third set current, then discharging to a third cut-off voltage with the third set current, then charging to a fourth cut-off voltage with a fourth set current, and then discharging to a fifth cut-off voltage with the third set current; wherein, the discharge capacity in the process of discharging from the second cut-off voltage to the third cut-off voltage is C0, the charge capacity in the process of charging from the third cut-off voltage to the fourth cut-off voltage is Q0, the discharge capacity in the process of discharging from the fourth cut-off voltage to the fifth voltage is C1, the discharge energy is Q1, the discharge capacity efficiency = C1 / C0, and the second energy efficiency = Q1 / Q0.

7. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method for evaluating the electrical performance of a battery cell as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for evaluating the electrical performance of a battery cell as described in any one of claims 1 to 5 is implemented.

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