Optimized testing method and system for simultaneous SOC-OCV and HPPC testing of lithium-ion batteries at different temperatures

Abstract

This invention provides a method and system for simultaneous SOC-OCV and HPPC optimization testing of lithium-ion batteries under different temperatures. The method includes: performing three standard cycle capacities (rest-discharge-rest-charge) at room temperature, defining the final discharge capacity as C1; placing the battery at different test temperatures and measuring the OCV at each temperature; placing the battery at room temperature and performing constant current and constant voltage discharge at a specific rate; placing the battery at different test temperatures and recording the OCV at each temperature; then performing a pulse discharge t1-rest t2-pulse charge t1-rest t2 process at this SOC; after the first rest t2, recharging back to the pulse discharge capacity and then performing pulse charge again, repeating the above steps until the battery is completely discharged. This invention solves the technical problem of inaccurate lithium battery test data caused by temperature changes, leading to potential vehicle safety hazards.

Description

Technical Field

[0001] This invention relates to the field of new energy testing, specifically to a method and system for simultaneously performing SOC-OCV and HPPC optimization tests on lithium-ion batteries at different temperatures. Background Technology

[0002] Major automakers are paying increasing attention to SOC-OCV testing strategies and battery power maps, with particular focus on battery system power performance. As a result, more and more people are researching SOC-OCV testing methods and HPPC testing methods.

[0003] The existing invention patent application document CN115267539A, entitled "A Joint Estimation Method for the State of Charge and Temperature of Lithium-ion Batteries for Automotive Applications," includes the following steps: Based on relevant parameters of the lithium-ion battery under test, a suitable electrical and thermal model of the battery is established. An electro-thermal coupling model is established using the dependency relationship between battery temperature and electrical model parameters. Simultaneously, the model parameters required for the joint estimation of the battery's state of charge and temperature are determined. Static capacity testing experiments and HPPC experiments are designed. Based on HPPC experimental data, recursive least squares method with a forgetting factor is used to identify the electrical model parameters, and a quantitative relationship between the electrical model parameters and battery SOC and temperature is established. Simultaneously, experimental data similar to those from real-vehicle operating conditions are acquired, and particle swarm optimization algorithm is used to identify the thermal model parameters. Finally, based on the electro-thermal coupling model and combined with the Kalman filter algorithm, the joint estimation of the battery's state of charge and temperature is achieved. From the specific implementation content of this prior art, it can be seen that this prior art solution uses an electro-thermal coupling model to evaluate the battery's state of charge and temperature based on HPPC experimental data, and this prior art solution performs a joint estimation of the state of charge and temperature. The existing patent application document CN114779107A, entitled "A Method for Estimating SOC of Lithium-ion Batteries Considering Temperature Influence," takes lithium-ion batteries as the research object. Based on the equivalent circuit model and heat generation power equation of lithium-ion batteries, it establishes a thermoelectric coupling model and introduces a temperature correction link, forming a closed-loop coupling from electricity to heat and back to electricity. In the aforementioned traditional testing methods, both SOC-OCV and HPPC testing methods adjust the SOC at the temperature to be tested. However, at low temperatures, the cell capacity will inevitably be incompletely released at low SOC, resulting in an underestimation of the actual SOC measured at low SOC. This leads to inaccurate static voltage, power map, and DCR map at low SOC, which cannot provide favorable data support for battery system power parameters and SOC calibration. Consequently, it may cause unexpected accidents such as undervoltage and excessive power causing vehicle stalling during actual start-up / climbing operation.

[0004] In summary, existing technologies have a technical problem: inaccurate lithium battery test data due to temperature changes can lead to potential driving safety hazards. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to solve the technical problem of inaccurate lithium battery test data caused by temperature changes in the prior art, which leads to potential driving safety hazards.

[0006] This invention solves the above-mentioned technical problems by employing the following technical solution: a method for simultaneously optimizing the SOC-OCV and HPPC tests for differential temperatures in lithium-ion batteries, comprising:

[0007] S1. Perform at least two standard cycle constant-capacity operations at a preset temperature using a rest-release-rest-charge method, and define the last discharge capacity as C1, so that the lithium-ion battery is in a fully charged state.

[0008] S2. Place the lithium-ion battery at different test temperatures until the cell surface temperature stabilizes at the test temperature, and measure the open circuit voltage OCV at different test temperatures respectively.

[0009] S3. Place the battery at the preset temperature until the surface temperature of the lithium-ion battery stabilizes at the preset temperature, and discharge the lithium-ion battery at a preset percentage of constant current and constant voltage according to the preset specific rate.

[0010] S4. Place the lithium-ion battery at different test temperatures until the surface temperature of the lithium-ion battery stabilizes at the test temperature, and record the open circuit voltage OCV at different test temperatures respectively.

[0011] S5. Under the current state of charge (SOC), a preset HPPC test procedure is added. Under the preset high state of charge (SOC), after the first rest period t2, the pulse amplifier's capacity is recharged and a pulse charging operation is performed to measure the DC impedance (DCR) data.

[0012] S6. Repeat the above steps until the battery is completely discharged to obtain test open circuit voltage data, DC impedance DCR data and mixed power pulse characteristic data, and then plot the SOC-OCV curve.

[0013] Compared with traditional SOC-OCV and HPPC testing methods, this invention performs optimized SOC-OCV and HPPC tests simultaneously at different temperatures, combining these two methods. By adding an HPPC testing component to the SOC-OCV method, only one test is needed to obtain the SOC-OCV discharge curve, charge / discharge power map, and DCR map value of the lithium battery. This invention is simple and easy to operate. The SOC-OCV test data obtained through this invention is closer to the actual SOC-OCV data of the battery, and the power map obtained after HPPC testing is more consistent with the accurate values ​​under different SOCs, better reflecting the true performance of the lithium battery. This has guiding significance for the actual start-up and hill-climbing processes of the vehicle.

[0014] More importantly, this invention patent can obtain the results of two different test items through a single test, which saves manpower and testing equipment resources, and at the same time shortens the testing cycle by at least half.

[0015] In a more specific technical solution, step S5 includes:

[0016] S51. Under preset temperature conditions, adjust the state of charge using the preset HPPC test section.

[0017] S52. Perform SOC-OCV and HPPC optimization tests on lithium-ion batteries at different test temperatures.

[0018] S53. Perform pulse amplification operation to recharge the pulse amplification capacity and measure the DC impedance (DCR) data.

[0019] This invention addresses the defect in existing technology where pulse amplification at 5C for 30 seconds under high SOC and pulse charging test results in deviation of SOC value during the pulse charging process. By charging the pulse amplifier back to its original capacity after pulse amplification and then performing pulse charging test, the accuracy of the power and DCR test results obtained after pulse charging test is improved.

[0020] In a more specific technical solution, in step S51, the different states of charge (SOC) include: 5% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC, 90% SOC, and 95% SOC.

[0021] In a more specific technical solution, in step S51, the device is left to stand for a first duration at a first temperature, for a second duration at a second temperature, and for a third duration at a third temperature.

[0022] In a more specific technical solution, step S51 includes the following preset HPPC test section: pulse discharge period t1, first rest period t2, pulse charge period t1, and second rest period t2.

[0023] In more specific technical solutions, preset temperature conditions include: preset ambient temperature conditions.

[0024] In a more specific technical solution, in step S52, the temperature to be measured includes: 25℃, -30℃, -20℃, -10℃, 0℃, 10℃, 45℃, and 55℃.

[0025] In a more specific technical solution, in step S52, the static voltage, power, and DC impedance DCR data of the lithium-ion battery are tested and obtained at no less than two different states of charge (SOC) under each test temperature using a temperature chamber-controlled charge-discharge equipment.

[0026] This invention provides results for two different test items in a single test, saving both manpower and testing equipment resources, while at least halving the testing cycle. Using a single temperature chamber-controlled charge / discharge device eliminates the need for frequent loading and unloading of batteries from different chambers during testing, effectively reducing the investment of manpower and resources, and minimizing interference with test results caused by prolonged exposure of batteries to different test temperatures. This invention also solves the problem of side reactions caused by high temperatures disrupting the chemical balance during battery charging and discharging.

[0027] In a more specific technical solution, in step S53, the lithium-ion battery is charged to the state of charge (SOC) corresponding to the pulse discharge operation using a temperature chamber-controlled charging and discharging device with a small current of 0.1C constant current.

[0028] This invention uses a small current of 0.1C for recharging, which can effectively prevent the risk of lithium plating in lithium batteries at low temperatures and improve the safety of testing operations.

[0029] This invention addresses the scenario where, under high SOC conditions, pulse charging occurs after high-current pulse discharge, resulting in a non-true SOC. By resting the pulse discharge capacity for a period of time (t2) before recharging, the test data closely approximates the actual SOC data for lithium-ion batteries.

[0030] In a more specific technical solution, the lithium-ion battery differential temperature simultaneous SOC-OCV and HPPC optimization testing system includes:

[0031] The battery charging and discharging module is used to perform at least two standard cycle constant capacity operations at a preset temperature in a rest-release-rest-charge manner, defining the last discharge capacity as C1, so that the lithium-ion battery is in a fully charged state.

[0032] The open-circuit voltage measurement module is used to place lithium-ion batteries at different test temperatures until the cell surface temperature stabilizes at the test temperature, and then measure the open-circuit voltage (OCV) at different test temperatures.

[0033] The constant current and constant voltage discharge module is used to place the battery at a preset temperature until the surface temperature of the lithium-ion battery stabilizes at the preset temperature, and to perform a preset percentage constant current and constant voltage discharge on the lithium-ion battery according to a preset specific rate. It is connected to the battery charge and discharge module and the open circuit voltage measurement module.

[0034] The open-circuit voltage measurement and recording module is used to place the lithium-ion battery at different test temperatures until the surface temperature of the lithium-ion battery stabilizes at the test temperature, and record the open-circuit voltage OCV at different test temperatures. The open-circuit voltage measurement and recording module is connected to the constant current and constant voltage discharge module.

[0035] The recharge pulse-charge DC impedance measurement module is used to add a preset HPPC test section under the current state of charge (SOC). Under the preset high state of charge (SOC), after the first rest period t2, the capacity of the pulse amplifier is recharged and a pulse charge operation is performed to measure the DC impedance (DCR) data. The recharge pulse-charge DC impedance measurement module is connected to the open circuit voltage measurement and recording module.

[0036] The SOC-OCV curve acquisition module is used to repeatedly call the aforementioned module until the battery is completely discharged, so as to obtain test open circuit voltage data, DC impedance DCR data and mixed power pulse characteristic data, and to plot the SOC-OCV curve. The SOC-OCV curve acquisition module is connected to the battery charging and discharging module and the recharge pulse DC impedance measurement module.

[0037] Compared with existing technologies, this invention has the following advantages: Compared with traditional SOC-OCV and HPPC testing methods, it simultaneously performs optimized SOC-OCV and HPPC tests at different temperatures, combining these two testing methods. By adding an HPPC testing component to the SOC-OCV method, only one test is needed to obtain the SOC-OCV discharge curve, charge / discharge power map, and DCR map value of the lithium battery. This invention is simple and easy to operate. The SOC-OCV test data obtained by this invention is closer to the actual SOC-OCV data of the battery, and the power map obtained after HPPC testing is more consistent with the accurate values ​​under different SOCs, better reflecting the true level of the lithium battery. This has guiding significance for the actual start-up and hill-climbing processes of the vehicle.

[0038] This invention addresses the defect in existing technology where pulse amplification at 5C for 30 seconds under high SOC and pulse charging test results in deviation of SOC value during the pulse charging process. By charging the pulse amplifier back to its original capacity after pulse amplification and then performing pulse charging test, the accuracy of the power and DCR test results obtained after pulse charging test is improved.

[0039] This invention provides results for two different test items in a single test, saving both manpower and testing equipment resources, while at least halving the testing cycle. Using a single temperature chamber-controlled charge / discharge device eliminates the need for frequent loading and unloading of batteries from different chambers during testing, effectively reducing the investment of manpower and resources, and minimizing interference with test results caused by prolonged exposure of batteries to different test temperatures. This invention also solves the problem of side reactions caused by high temperatures disrupting the chemical balance during battery charging and discharging.

[0040] This invention uses a small current of 0.1C for recharging, which can effectively prevent the risk of lithium plating in lithium batteries at low temperatures and improve the safety of testing operations.

[0041] This invention addresses the scenario where, at high SOC (State of Charge), pulse charging following high-current pulse discharge results in a non-realistic SOC. By recharging the pulsed battery back to its original capacity after a first rest period (t2) before resuming pulse charging, the invention ensures that the test data closely reflects the actual SOC of lithium-ion batteries. This invention resolves the technical problem in existing technologies where inaccurate lithium battery test data due to temperature variations leads to potential vehicle safety hazards. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the steps of the method for simultaneously performing SOC-OCV and HPPC optimization tests on the differential temperature of lithium-ion batteries in Embodiment 1 of the present invention.

[0043] Figure 2 This is a schematic diagram illustrating the specific implementation of the method for simultaneously performing SOC-OCV and HPPC optimization tests on the differential temperature of lithium-ion batteries in Embodiment 2 of the present invention.

[0044] Figure 3 This is a schematic diagram of the processing results of the conventional test method in Embodiment 1 of the present invention;

[0045] Figure 4 This is a schematic diagram illustrating the specific implementation results of the method for simultaneously performing SOC-OCV and HPPC optimization tests on the differential temperature of lithium-ion batteries in Embodiment 1 of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] like Figure 1 As shown, the method provided by this invention includes the following basic steps:

[0049] S1. Perform standard cycle capacitance (rest-release-rest-charge) 3 times at room temperature, and define the last discharge capacity as C1. The battery is fully charged in the last step of capacitance.

[0050] S2. Place the battery at different test temperatures for several hours until the cell surface temperature stabilizes at the test temperature, and measure the OCV (corresponding to 100% SOC) at different test temperatures respectively.

[0051] S3. Place the battery at room temperature until the battery surface temperature stabilizes at room temperature, and then discharge the battery at a certain percentage of constant current and constant voltage according to a specific rate.

[0052] S4. Place the battery under different test temperatures until the battery surface temperature stabilizes at the test temperature. Record the OCV at different test temperatures. Then, under this SOC, perform pulse discharge t1-rest t2-pulse charge t1-rest t2. Under high SOC, after the first rest t2, recharge the pulse discharge capacity and then perform pulse charge again. Repeat the above steps S1 to S4 until the battery is completely discharged.

[0053] In this embodiment, eight different temperatures were tested, namely 25 / -30 / -20 / -10 / 0 / 10 / 45 / 55℃. At each temperature, the static voltage, power, and DCR value were tested at 11 different SOCs.

[0054] In this embodiment, the SOC of the battery cells is adjusted to:

[0055] SOC was adjusted at 0.33°C for 5% / 10% / 20% / 30% / 40% / 50% / 60% / 70% / 80% / 90% / 95% SOC. SOC was adjusted at room temperature, and SOC-OCV and HPPC optimization tests were performed at the test temperature.

[0056] In this embodiment, the resting time is defined at different test temperatures as follows: 1 hour at room temperature, 3 hours at high temperature, and 5 hours at low temperature. t1 is defined as 30 seconds, and t2 as 40 seconds. Taking 25°C as an example, pulse discharge is performed for 30 seconds at 5C under high SOC, pulse discharge for 30 seconds at 2C under low SOC, pulse charge for 30 seconds at 3.75C under low SOC, and pulse charge for 30 seconds at 1C under high SOC. The pulse discharge and charging currents at other temperatures are determined according to the corresponding current matrix table.

[0057] In this embodiment, performing pulse amplification for 30 seconds at 5C under high SOC followed by pulse charging test will cause the SOC value to deviate too much during the pulse charging process. The power and DCR obtained after the pulse charging test will be inaccurate. Therefore, after pulse amplification, the capacity of the pulse amplifier needs to be charged back before pulse charging test.

[0058] In this embodiment, the method for recharging the pulsed discharge capacity is as follows: charge with a small current of 0.1C to the corresponding SOC level before pulsed discharge. The reason for recharging with a small current of 0.1C is to prevent the risk of lithium plating in the lithium battery at low temperatures.

[0059] In this embodiment, taking the company's ternary 55Ah battery cell as an example, the upper and lower limits of the voltage during the charging and discharging process of the battery cell are defined as follows: T>0℃, 2.8-4.3V, T≤0℃, 2.4-4.3V.

[0060] A single temperature chamber can be used for charging and discharging testing, eliminating the need to frequently move batteries up and down different temperature chambers during the testing process. This effectively reduces the investment of manpower and resources, and minimizes the significant deviations in test results caused by batteries being left at different test temperatures for too long.

[0061] Example 2

[0062] Taking a specific test at 25℃ as an example:

[0063] S1' At 25℃, let it rest for 30 minutes, then discharge the battery at a constant current rate of 1 / 3C, let it rest for 30 minutes, and then charge the battery at a constant current and constant voltage rate of 1 / 3C. Repeat the "rest-discharge-rest-charge" cycle 3 times, and take the discharge capacity of the last discharge as the actual discharge capacity C1 of the battery.

[0064] S2', let stand for 1 hour, then measure OCV;

[0065] S3': Discharge the battery at a constant current and constant voltage rate of 1 / 3C to 95% SOC, let it rest for 1 hour, and measure OCV.

[0066] S4', pulse at 5C for 30 seconds, then rest for 40 seconds;

[0067] S5', adjust to the SOC level before pulse amplification using a constant current charge of 0.1C;

[0068] S6', Pulse charge at 1C for 30 seconds, then rest for 40 seconds;

[0069] S7': Discharge the battery at a constant current and constant voltage rate of 1 / 3C to 90% SOC, let it rest for 1 hour, and measure OCV.

[0070] S8', pulse at 5C for 30 seconds, then rest for 40 seconds;

[0071] S9', adjust to the SOC level before pulse amplification using a constant current charge of 0.1C;

[0072] S10', pulse charge at 3.75C for 30 seconds, then rest for 40 seconds;

[0073] S11', repeat steps 7-10 9 times to adjust SOC from 90% SOC to 10% SOC;

[0074] S12': Discharge the battery at a constant current and constant voltage rate of 1 / 3C to adjust it to 5% SOC, let it rest for 1 hour, and measure the OCV.

[0075] S13', pulse discharge at 2C for 30 seconds, then rest for 40 seconds;

[0076] S14', Adjust to the SOC level before pulse amplification using a constant current charge of 0.1C;

[0077] S15', pulse charge at 3.75C for 30 seconds, then rest for 40 seconds;

[0078] S16', Empty and remove from the cabinet.

[0079] The same test method was used for other different temperatures.

[0080] This testing method has now been applied to the company's ternary lithium-ion battery cells. Taking a 55Ah cell as an example, the test results are shown below:

[0081] like Figure 3 As shown, Method 1: Traditional testing method: Reduce the SOC at the temperature to be tested.

[0082] like Figure 4 As shown, Method 2: The testing method demonstrated in this invention.

[0083]

[0084]

[0085]

[0086] Based on the test results above, Method 1 shows a significant difference in SOC-OCV between low temperature and room temperature, especially in the low-temperature, low-SOC range. Method 2, on the other hand, shows a difference of approximately 10mV in SOC-OCV across different temperatures, effectively avoiding the inaccurate SOC results caused by low-temperature, low-SOC conditions. Furthermore, the power map values ​​obtained using Method 2 provide excellent feedback in vehicle testing, significantly reducing accidents caused by undervoltage or overvoltage during vehicle startup and hill climbing.

[0087] In summary, compared with traditional SOC-OCV and HPPC testing methods, this invention combines optimized SOC-OCV and HPPC tests conducted simultaneously at different temperatures. By adding an HPPC testing component to the SOC-OCV method, only one test is needed to obtain the SOC-OCV discharge curve, charge / discharge power map, and DCR map value of the lithium battery. This invention is simple and easy to operate. The SOC-OCV test data obtained through this invention is closer to the actual SOC-OCV data of the battery, and the power map obtained after HPPC testing is more consistent with the accurate values ​​under different SOCs, better reflecting the true performance of the lithium battery. This has significant guiding value for the actual start-up and hill-climbing processes of the vehicle.

[0088] This invention addresses the defect in existing technology where pulse amplification at 5C for 30 seconds under high SOC and pulse charging test results in deviation of SOC value during the pulse charging process. By charging the pulse amplifier back to its original capacity after pulse amplification and then performing pulse charging test, the accuracy of the power and DCR test results obtained after pulse charging test is improved.

[0089] This invention provides results for two different test items in a single test, saving both manpower and testing equipment resources, while at least halving the testing cycle. Using a single temperature chamber-controlled charge / discharge device eliminates the need for frequent loading and unloading of batteries from different chambers during testing, effectively reducing the investment of manpower and resources, and minimizing interference with test results caused by prolonged exposure of batteries to different test temperatures. This invention also solves the problem of side reactions caused by high temperatures disrupting the chemical balance during battery charging and discharging.

[0090] This invention uses a small current of 0.1C for recharging, which can effectively prevent the risk of lithium plating in lithium batteries at low temperatures and improve the safety of testing operations.

[0091] This invention addresses the scenario where, at high SOC (State of Charge), pulse charging following high-current pulse discharge results in a non-realistic SOC. By recharging the pulsed battery back to its original capacity after a first rest period (t2) before resuming pulse charging, the invention ensures that the test data closely reflects the actual SOC of lithium-ion batteries. This invention resolves the technical problem in existing technologies where inaccurate lithium battery test data due to temperature variations leads to potential vehicle safety hazards.

[0092] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simultaneous SOC-OCV and HPPC optimization testing of lithium-ion battery at different temperatures, characterized in that, The method includes: S1. Using a rest-release-rest-charge method, perform at least two standard cycle constant-capacity operations at a preset temperature, and define the last discharge capacity as C1, so that the lithium-ion battery is in a fully charged state. S2. Place the lithium-ion battery at different test temperatures until the cell surface temperature stabilizes at the test temperature, and measure the open circuit voltage OCV at different test temperatures respectively; S3. Place the battery at the preset temperature until the surface temperature of the lithium-ion battery stabilizes at the preset temperature, and discharge the lithium-ion battery at a preset percentage of constant current and constant voltage according to a preset specific rate. S4. Place the lithium-ion battery at different test temperatures until the surface temperature of the lithium-ion battery stabilizes at the test temperature, and record the open circuit voltage OCV at different test temperatures respectively; S5. Under the current state of charge (SOC), a preset HPPC test procedure is added. Under the preset high state of charge (SOC), after the first rest period t2, the pulse amplifier's capacity is recharged, and a pulse charging operation is performed to measure the DC impedance (DCR) data. Record the OCV at different test temperatures, and then perform pulse discharge period t1-first rest period t2-pulse charge period t1-first rest period t2 under the current state of charge (SOC). Under high SOC, after the first rest period t2, recharge the pulse discharge capacity and then perform pulse charge again. Repeat S1 to S4 until the lithium-ion battery is completely discharged. S6. Repeat the above steps until the battery is completely discharged to obtain the test open circuit voltage data, the DC impedance DCR data, and the mixed power pulse characteristic data, and then plot the SOC-OCV curve.

2. The method for simultaneously optimizing the SOC-OCV and HPPC tests of lithium-ion batteries based on temperature differences according to claim 1, characterized in that, Step S5 includes: S51. Under preset temperature conditions, the state of charge is adjusted using the preset HPPC test unit; S52. At different test temperatures, perform SOC-OCV and HPPC optimization tests on the lithium-ion battery respectively. S53. Perform pulse amplification operation to recharge the pulse amplification capacity and measure the DC impedance DCR data.

3. The method for simultaneously optimizing the SOC-OCV and HPPC tests of lithium-ion batteries based on temperature differences according to claim 2, characterized in that, In step S51, the different states of charge (SOC) include: 5% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC, 90% SOC, and 95% SOC.

4. The method for simultaneous SOC-OCV and HPPC optimization testing of lithium-ion batteries at different temperatures according to claim 2, wherein in step S51, the battery is placed for a first duration at a first temperature, placed for a second duration at a second temperature, and placed for a third duration at a third temperature.

5. The method for simultaneously performing SOC-OCV and HPPC optimization tests on lithium-ion batteries according to claim 2, wherein in step S51, the pre-set HPPC test unit includes: Pulse release period t1, first rest period t2, pulse charging period t1, second rest period t2.

6. The method for simultaneously optimizing SOC-OCV and HPPC tests on lithium-ion battery differential temperatures according to claim 2, wherein the preset temperature conditions include: Preset ambient temperature conditions.

7. The method for simultaneously optimizing the SOC-OCV and HPPC tests of lithium-ion batteries based on temperature differences according to claim 2, characterized in that, In step S52, the temperatures to be measured include: 25℃, -30℃, -20℃, -10℃, 0℃, 10℃, 45℃, and 55℃.

8. The method for simultaneously optimizing the SOC-OCV and HPPC tests of lithium-ion batteries based on differential temperature as described in claim 2, characterized in that, In step S52, at each of the test temperatures, the static voltage, power, and DC impedance DCR data of the lithium-ion battery are tested and obtained using a temperature chamber-controlled charge-discharge device at no less than two different states of charge (SOC).

9. The method for simultaneously optimizing the SOC-OCV and HPPC tests of lithium-ion batteries based on differential temperature as described in claim 2, characterized in that, In step S53, the lithium-ion battery is charged to the state of charge (SOC) corresponding to the pulse discharge operation using a temperature chamber-controlled charging and discharging device with a small constant current of 0.1C.

10. A system for simultaneously optimizing the SOC-OCV and HPPC of lithium-ion batteries based on temperature differences, used to perform the method for simultaneously optimizing the SOC-OCV and HPPC of lithium-ion batteries based on temperature differences as described in any one of claims 1 to 9, characterized in that, The system includes: The battery charging and discharging module is used to perform at least two standard cycle constant capacity operations at a preset temperature in a rest-release-rest-charge manner, defining the last discharge capacity as C1, so that the lithium-ion battery is in a fully charged state. An open-circuit voltage measurement module is used to place the lithium-ion battery at different test temperatures until the cell surface temperature stabilizes at the test temperature, and measure the open-circuit voltage (OCV) at different test temperatures respectively. A constant current and constant voltage discharge module is used to place the battery at the preset temperature until the surface temperature of the lithium-ion battery stabilizes at the preset temperature, and to perform constant current and constant voltage discharge on the lithium-ion battery according to a preset specific rate and a preset percentage. The constant current and constant voltage discharge module is connected to the battery charging and discharging module and the open circuit voltage measurement module. An open-circuit voltage measurement and recording module is used to place the lithium-ion battery at different test temperatures until the surface temperature of the lithium-ion battery stabilizes at the test temperature, and record the open-circuit voltage OCV at different test temperatures. The open-circuit voltage measurement and recording module is connected to the constant current and constant voltage discharge module. The recharge pulse-charge DC impedance measurement module is used to add a preset HPPC test section under the current state of charge (SOC). Under the preset high state of charge (SOC), after the first rest period t2 has passed, the capacity of the pulse amplifier is recharged and a pulse charging operation is performed to measure the DC impedance (DCR) data. The recharge pulse-charge DC impedance measurement module is connected to the open circuit voltage measurement and recording module. The SOC-OCV curve acquisition module is used to repeatedly call the aforementioned module until the battery is completely discharged, so as to obtain the test open circuit voltage data, the DC impedance DCR data and the mixed power pulse characteristic data, and to plot the SOC-OCV curve. The SOC-OCV curve acquisition module is connected to the battery charging and discharging module and the recharge pulse DC impedance measurement module.

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