A lithium ion battery peak power testing method

Abstract

This invention relates to the field of lithium-ion battery testing technology, and specifically to a method for testing the peak power of lithium-ion batteries. Based on the qualified peak current value of the lithium-ion battery under a first state of charge, a peak current test value under a second state of charge is determined. Based on the peak current test value, a current pulse test of a preset time is performed on the lithium-ion battery under test to determine the battery terminal voltage and the actual pulse duration at the end of the test. It is then determined whether the battery terminal voltage falls within the qualified voltage range and whether the actual pulse duration reaches the preset time. If both are yes, the peak current test value is determined to be the qualified peak current value under the second state of charge. If either is no, a new peak current test value is determined based on the battery terminal voltage, the actual pulse duration, and the peak current test value, and the above steps are repeated until the peak power is determined. This invention constructs an efficient and stable automated method for testing battery peak power.

Description

Technical Field

[0001] This specification relates to the field of lithium-ion battery testing technology, and in particular to a method for testing the peak power of lithium-ion batteries. Background Technology

[0002] Peak power testing of power batteries is a core method for evaluating battery power performance. It is used to verify the battery's power response and voltage stability in scenarios such as electric vehicle acceleration, hill climbing, and regenerative braking. It is also applicable to complex scenarios such as takeoff, hovering, climbing, cruise, descent, and landing hovering of electric vertical takeoff and landing aircraft. Through peak power testing, key data support can be provided for the matching of vehicle and aircraft power systems, calibration of battery management system power strategies, and setting of safety boundaries, ensuring reliable battery operation under high load, high frequency, and multi-scenario dynamic conditions.

[0003] Currently, the mainstream method for peak power testing of power batteries is the trial-and-error method. This method adjusts the battery to the target State of Charge (SOC) and temperature, and then uses an empirically selected current for constant current pulse testing. If the voltage at the end of the pulse is higher than the cutoff upper limit, the current is increased and the test is repeated; if it is lower than the cutoff voltage, the current is decreased and the test is repeated, until the voltage falls into the acceptable range near the cutoff voltage. This method requires a complete restoration of the battery state after each attempt, making the test very time-consuming. The initial current and adjustment step size rely entirely on the engineer's experience, and the number of cycles increases dramatically when the deviation is large. Repeated high-current surges can also accelerate battery aging and affect the accuracy of subsequent tests.

[0004] To address the inefficiency of trial-and-error methods, a new method for testing battery peak power is proposed based on the industry standard QC / T 1240-2025, "Test Method for Peak Power of Power Batteries for Electric Vehicles." This method first uses SOC-OCV (Open Circuit Voltage) and DC internal resistance R to fit functions OCV=f(SOC) and R=g(SOC). Then, the predicted current is calculated by substituting the cutoff voltage into the formula U=OCV-R·I. After actual measurement, the correction amount ΔI is calculated using a fixed internal resistance R based on the voltage deviation, and the adjustment is verified. However, this method requires time-consuming and demanding SOC-OCV and DC internal resistance tests. The accuracy of both prediction and correction depends on the precision of the fitted internal resistance R. If only high-rate current data provided by the manufacturer is used instead of the actual peak current, or if the pulse duration is mismatched, R will be inaccurate. When R is inaccurate, the correction amount ΔI calculated based on a fixed R has a large deviation, potentially requiring multiple repeated tests, which is also time-consuming.

[0005] Another Chinese invention patent, CN118884247B, discloses a method for estimating and testing the peak current of lithium-ion batteries. It extracts a "voltage estimation formula" and a "current-internal resistance relationship" from historical battery measurement data, substitutes the cutoff voltage to deduce the initial current, and then uses a preset fixed target voltage and the current deviation to iteratively calculate the next test current. However, this method fails when historical data is missing or incomplete. Furthermore, because its target voltage is fixed, when the deviation between the actual voltage and the target voltage is appropriate, the algorithm mechanically and significantly adjusts back, causing the current to oscillate between being too high and too low, making rapid convergence difficult.

[0006] Therefore, this specification provides a method for testing the peak power of lithium-ion batteries. Summary of the Invention

[0007] This specification provides a method for testing the peak power of lithium-ion batteries, in order to partially solve the aforementioned problems existing in the prior art.

[0008] The following technical solution is adopted in this specification: This manual provides a method for testing the peak power of lithium-ion batteries, including: S1. Obtain the peak current qualification value of the lithium-ion battery under test in the first state of charge; S2. Based on the peak current qualification value of the lithium-ion battery under test in the first state of charge, determine the peak current test value of the lithium-ion battery under test in the second state of charge, wherein the remaining battery capacity represented by the first state of charge is greater than the remaining battery capacity represented by the second state of charge. S3. Based on the peak current test value, perform a current pulse test on the lithium-ion battery under test in the second state of charge for a preset time to determine the battery terminal voltage and actual pulse duration at the end of the test. S4. Determine whether the battery terminal voltage falls within a preset qualified voltage range, and whether the actual pulse duration reaches the preset time; S5. If both are yes, then the peak current test value is determined to be the peak current qualification value of the lithium-ion battery under test in the second state of charge, and the peak power of the lithium-ion battery under test is calculated based on the peak current test value. S6. If any of them are not true, then based on the battery terminal voltage, the actual pulse duration and the peak current test value, determine the peak current test value for the next current pulse test, and repeat steps S3 to S6 until the peak current qualification value of the lithium-ion battery under test in the second state of charge is obtained, and calculate the peak power of the lithium-ion battery under test based on the peak current qualification value in the second state of charge.

[0009] Based on the aforementioned technical means, this solution constructs a highly efficient, universal, and stable automated testing method for battery peak power. It transforms the reliance on experience, complex models, or historical data into the utilization of the battery's own physical characteristics and dynamic measured feedback, achieving a good balance between improving efficiency and ensuring accuracy and safety. By utilizing the known acceptable peak current value at high SOC, the initial peak current test value at low SOC is calculated, making the initial test current very close to the true value. This significantly reduces the number of subsequent iterations from S3 to S6, transforming the lithium-ion battery peak power testing process from "repeated trial and error" to "precise prediction + a few verifications," significantly shortening the total testing time for a single SOC point and even the entire SOC range. This method is also applicable to brand-new batteries, aged batteries, or batteries with incomplete data, greatly improving the universality and ease of use of the testing method. Only a conservative initial value based on specifications or experience is needed to start, eliminating the need for any complex pre-test characteristics or historical data tables. The judgment and adjustment logic in step S6 does not preset a fixed voltage target value. Instead, it dynamically determines the adjustment target based on the actual deviation of the voltage or time measured in the previous test. This mechanism of "larger deviation, larger adjustment; smaller deviation, finer adjustment" fundamentally eliminates mechanical over-adjustment, making the iteration process more intelligent and stable. It can stably converge to the final peak current and peak power, avoiding oscillations around the true value. The peak power finally confirmed in step S5 is based on real physical test results, not indirect calculations from any model. Because the initial prediction is accurate and the correction process is stable, the final converged result can truly reflect the battery's limit capability under any state of charge.

[0010] Furthermore, the calculation expression for determining the peak current test value in S2 is as follows:

[0011] in, The peak current test value of the lithium-ion battery under test during the first current pulse test in the second state of charge. The lithium-ion battery under test has undergone the first state of charge. The peak current qualification value obtained after the current pulse test; , , These represent the percentage of remaining battery capacity of the lithium-ion battery under test. These are the preset estimation coefficients.

[0012] Furthermore, the current pulse test is a discharge test of the lithium-ion battery under test; the preset voltage qualification range is a discharge voltage qualification range. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the battery terminal voltage does not fall within the qualified discharge voltage range, determine whether the battery terminal voltage is within a preset first voltage range. If so, then based on the open-circuit voltage of the lithium-ion battery before discharge, the battery terminal voltage, and the discharge cutoff voltage of the lithium-ion battery under test, a first voltage adjustment parameter is determined; based on the first voltage adjustment parameter, a preset redundant voltage, and the discharge cutoff voltage, a first expected voltage for the next discharge test is determined; based on the peak current test value, the first expected voltage, the battery open-circuit voltage, and the battery terminal voltage, the peak current test value for the next discharge test is determined. If not, then the second expected voltage for the next discharge test is determined based on the preset second voltage adjustment parameter, the redundant voltage, and the discharge cutoff voltage; the peak current test value for the next discharge test is determined based on the second expected voltage, the battery open circuit voltage, the battery terminal voltage, and the peak current test value.

[0013] Furthermore, the formula for calculating the peak current value of the next discharge test is as follows:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] in, This is the peak current test value for the next discharge test. For the preset time, The peak current test value of the current discharge test. The actual pulse duration, The open-circuit voltage of the lithium-ion battery under test before discharge is given. The discharge cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the first voltage regulation parameter. The first desired voltage; The preset second voltage adjustment parameter, The second desired voltage; This is the preset first voltage range.

[0021] Furthermore, the current pulse test is a discharge test of the lithium-ion battery under test; the actual pulse duration is the actual discharge time of the discharge test. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the actual discharge time of the lithium-ion battery under test is less than the preset time, determine whether the actual discharge time is within the preset first time interval. If so, then based on the actual discharge time and the preset time, a third voltage adjustment parameter is determined; based on the third voltage adjustment parameter, the preset redundant voltage, and the discharge cutoff voltage of the lithium-ion battery under test, a third expected voltage for the next discharge test is determined; based on the peak current test value, the third expected voltage, the battery open-circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage, a peak current test value for the next discharge test is determined. If not, then the fourth desired voltage for the next discharge test is determined based on the preset fourth voltage adjustment parameter, the redundant voltage, and the discharge cutoff voltage; the peak current test value for the next discharge test is determined based on the peak current test value, the fourth desired voltage, the battery open circuit voltage, and the battery terminal voltage.

[0022] Furthermore, the formula for calculating the peak current value of the next discharge test is as follows:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] in, The peak current test value of the current discharge test. This refers to the actual discharge time of the current discharge test; The preset time; This is the peak current test value for the next discharge test; The open-circuit voltage of the lithium-ion battery under test before discharge is given. The discharge cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the third voltage regulation parameter. The third desired voltage; When the preset fourth voltage adjustment parameter is used, The fourth desired voltage; This is the preset first time interval.

[0030] Furthermore, the current pulse test is a charging test of the lithium-ion battery under test; the preset voltage qualification range is a charging voltage qualification range. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the battery terminal voltage does not fall within the qualified charging voltage range, determine whether the battery terminal voltage is within a preset second voltage range; If so, then based on the open-circuit voltage of the lithium-ion battery before charging, the battery terminal voltage, and the charging cutoff voltage of the lithium-ion battery under test, a fifth voltage adjustment parameter is determined; based on the fifth voltage adjustment parameter, a preset redundant voltage, and the charging cutoff voltage, a fifth desired voltage for the next charging test is determined; based on the peak current test value, the fifth desired voltage, the battery open-circuit voltage, and the battery terminal voltage, the peak current test value for the next charging test is determined. If not, then the sixth expected voltage for the next charging test is determined based on the preset sixth voltage adjustment parameter, the redundant voltage, and the charging cutoff voltage; the peak current test value for the next charging test is determined based on the sixth expected voltage, the battery open circuit voltage, the battery terminal voltage, and the peak current test value.

[0031] Furthermore, the formula for calculating the peak current test value of the next charging test is as follows:

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] in, This will be the peak current test value for the next charging test. For the preset time, The peak current test value for the current charging test. The actual pulse duration, The open-circuit voltage of the lithium-ion battery under test before charging. The charging cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the fifth voltage regulation parameter. The fifth desired voltage; When the preset sixth voltage adjustment parameter is used, The sixth desired voltage; This is the preset second voltage range.

[0039] Furthermore, the current pulse test is a charging test of the lithium-ion battery under test; the actual pulse duration is the actual charging time of the charging test. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the actual charging time of the lithium-ion battery under test is less than the preset time, determine whether the actual charging time is within the preset second time interval. If so, then the seventh voltage adjustment parameter is determined based on the actual charging time and the preset time; the seventh expected voltage for the next charging test is determined based on the seventh voltage adjustment parameter, the preset redundant voltage, and the charging cutoff voltage of the lithium-ion battery under test; the peak current test value for the next charging test is determined based on the peak current test value, the seventh expected voltage, the battery open circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage. If not, then the eighth expected voltage for the next charging test is determined based on the preset eighth voltage adjustment parameter, the redundant voltage, and the charging cutoff voltage; the peak current test value for the next charging test is determined based on the peak current test value, the eighth expected voltage, the battery open circuit voltage, and the battery terminal voltage.

[0040] Furthermore, the formula for calculating the peak current test value of the next charging test is as follows:

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047] in, The peak current test value for the current charging test. This refers to the actual charging time during the current charging test. The preset time; The peak current test value for the next charging test; The open-circuit voltage of the lithium-ion battery under test before charging. The charging cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the seventh voltage regulation parameter. The seventh desired voltage; When the preset eighth voltage adjustment parameter is used, The eighth desired voltage; This is the preset second time interval.

[0048] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: This solution constructs an efficient, universal, and stable automated method for testing battery peak power. It transforms reliance on experience, complex models, or historical data into utilization of the battery's own physical characteristics and dynamic measured feedback, achieving a good balance between improved efficiency and ensuring accuracy and safety. By using the known acceptable peak current value at high SOC, the initial peak current test value at low SOC is calculated, making the initial test current very close to the true value. This significantly reduces the number of subsequent iterations from S3 to S6, transforming the lithium-ion battery peak power testing process from "repeated trial and error" to "precise prediction + a few verifications," significantly shortening the total testing time for a single SOC point and even the entire SOC range. This method is also applicable to brand-new batteries, aged batteries, or batteries with incomplete data, greatly improving the universality and ease of use of the testing method. Only a conservative initial value based on specifications or experience is needed to start, eliminating the need for any complex pre-testing characteristics or historical data tables. The judgment and adjustment logic in step S6 does not preset a fixed voltage target value. Instead, it dynamically determines the adjustment target based on the actual deviation of the voltage or time measured in the previous test. This mechanism of "larger deviation, larger adjustment; smaller deviation, finer adjustment" fundamentally eliminates mechanical over-adjustment, making the iteration process more intelligent and stable. It can stably converge to the final peak current and peak power, avoiding oscillations around the true value. The peak power finally confirmed in step S5 is based on real physical test results, not indirect calculations from any model. Because the initial prediction is accurate and the correction process is stable, the final converged result can truly reflect the battery's limit capability under any state of charge. Attached Figure Description

[0049] The accompanying drawings, which are included to provide a further understanding of this specification and form part of this specification, illustrate exemplary embodiments and are used to explain this specification, but do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a method for testing the peak power of a lithium-ion battery, as provided in an embodiment of this specification. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0051] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0052] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0053] Figure 1 A flowchart illustrating a peak power testing method for lithium-ion batteries provided in this specification includes the following steps: S1: Obtain the peak current qualification value of the lithium-ion battery under test in the first state of charge.

[0054] S2: Based on the peak current qualification value of the lithium-ion battery under test in the first state of charge, determine the peak current test value of the lithium-ion battery under test in the second state of charge, wherein the remaining battery capacity represented by the first state of charge is greater than the remaining battery capacity represented by the second state of charge.

[0055] This invention can perform peak power testing of lithium-ion batteries based on the linkage of commercially available battery testing software with programmable and customizable steps, battery charge and discharge testing system, high and low temperature environment test chamber, and test bench, combined with a peak power testing method for lithium-ion batteries provided in the embodiments of this specification.

[0056] In one or more embodiments of this specification, for lithium-ion batteries undergoing peak power testing, there is an inherent physical characteristic: the peak current of the battery at 100% SOC is the maximum value within the entire SOC range at its current temperature. As the SOC decreases, the peak current discharge capability gradually weakens. That is, at the same temperature, the battery's peak discharge capability is strongest when fully charged (100% SOC), and gradually weakens as the charge (SOC) decreases.

[0057] Therefore, the method can initially obtain the peak current qualification value (i.e., the peak current under the first state of charge) of the lithium-ion battery under test (i.e. the lithium-ion battery with the peak power to be tested) at a certain temperature, which has been determined by actual measurement or engineer experience.

[0058] Furthermore, based on the peak current qualification value of the lithium-ion battery under test in the first state of charge, and utilizing the aforementioned physical characteristics, the peak current test value of the lithium-ion battery under test in the second state of charge can be determined. At this point, the remaining battery capacity represented by the first state of charge is greater than the remaining battery capacity represented by the second state of charge.

[0059] Here, the formula for calculating the peak current test value is:

[0060] in, The peak current value is the value of the lithium-ion battery under test during the first current pulse test under the second state of charge. The lithium-ion battery under test under its first state of charge has undergone The peak current qualification value obtained after the current pulse test. , , These represent the percentage of remaining charge of the lithium-ion battery under test. These are the preset estimation coefficients.

[0061] Of course, it is worth noting that in this specification, from steps S1 to S6 until the peak power of the lithium-ion battery is determined, the peak current test of the lithium-ion battery in the first state of charge and the lithium-ion battery in the second state of charge is carried out at the same temperature. Therefore, the temperature will not be described again in the following, and it is assumed that the subsequent process is carried out at the same temperature.

[0062] S3: Based on the peak current test value, perform a current pulse test on the lithium-ion battery under test in the second state of charge for a preset time to determine the battery terminal voltage and actual pulse duration at the end of the test.

[0063] In one or more embodiments of this specification, based on the peak current test value under the second state of charge, a current pulse test for a preset time can be performed on the lithium-ion battery under test in the second state of charge to determine the battery terminal voltage and the actual pulse duration at the end of the current pulse test. The current pulse test includes a discharge test and a charge test of the lithium-ion battery under test. If the current pulse test is a discharge test, the actual pulse duration is the actual discharge time of the lithium-ion battery under test; if the current pulse test is a charge test, the actual pulse duration is the actual charging time of the lithium-ion battery under test.

[0064] S4: Determine whether the battery terminal voltage falls within a preset acceptable voltage range and whether the actual pulse duration reaches the preset time. If both are yes, proceed to step S5. If either is no, proceed to step S6.

[0065] In one or more embodiments of this specification, after performing a current pulse test on the lithium-ion battery under test based on the peak current test value, the battery terminal voltage can be determined based on the results of the current pulse test to determine whether it falls within the preset voltage qualification range and whether the actual pulse duration reaches the preset time, thereby determining whether the peak current test value meets the peak power calculation conditions of the lithium-ion battery under test in the second state of charge.

[0066] Since the current pulse test includes both discharge and charge tests of the lithium-ion battery under test, different tests have different peak power calculation conditions for discharge and charge tests.

[0067] For the discharge test, after the lithium-ion battery under test has been discharged for a preset time, if the actual discharge time reaches the preset time and the measured battery terminal voltage does not fall into the preset qualified discharge voltage range, it means that the lithium-ion battery under test still has potential and the current can be increased further. In other words, if the current peak current test value is too small, it means that the current peak current test value does not meet the peak power calculation conditions of the lithium-ion battery under test in the second state of charge.

[0068] Alternatively, during the discharge test, the actual discharge time of the lithium-ion battery under test does not reach the preset time. When the measured actual discharge time of the lithium-ion battery under test is less than the preset time (i.e., the target discharge time originally set for the discharge test), it means that the battery terminal voltage of the lithium-ion battery under test triggers the preset discharge cutoff voltage of the lithium-ion battery under test before the end pulse. At this time, the measured battery terminal voltage is equivalent to the discharge cutoff voltage of the lithium-ion battery under test. The current peak current test value is too large, and the battery cannot withstand it. The peak current test value needs to be reduced. This indicates that the current peak current test value does not meet the peak power calculation conditions of the lithium-ion battery under test in the second state of charge.

[0069] Therefore, for the discharge test, after the lithium-ion battery under test has undergone a discharge test for a preset time, the battery terminal voltage measured at the end of the discharge test must fall within the preset qualified discharge voltage range (i.e., ...). )), The preset discharge voltage threshold, The discharge cutoff voltage of the lithium-ion battery under test is _____. for The safety redundancy voltage reserved above is only sufficient to ensure that the peak current test value meets the peak power calculation conditions of the lithium-ion battery under test in the second state of charge if the actual discharge time of the discharge test reaches the preset time and the battery terminal voltage falls into the qualified discharge voltage range at the end.

[0070] In this specification, for the charging test, after the lithium-ion battery under test has been charged for a preset time, if the measured battery terminal voltage does not fall into the preset qualified charging voltage range after the actual charging time has reached the preset time, it means that the battery terminal voltage of the lithium-ion battery under test has not yet reached the upper limit and can still accept a larger current. In other words, the current peak current test value is too small, which means that the current peak current test value does not meet the peak power calculation conditions of the lithium-ion battery under test in the second state of charge.

[0071] Alternatively, during the charging test, the actual charging time of the lithium-ion battery under test does not reach the preset time. When the measured actual charging time of the lithium-ion battery under test is less than the preset time (i.e., the target charging time originally set for the charging test), it means that during the charging process, the battery terminal voltage of the lithium-ion battery under test prematurely triggers the preset charging cutoff voltage of the lithium-ion battery under test, resulting in the actual pulse duration being less than the preset time. At this time, the measured battery terminal voltage is equivalent to the charging cutoff voltage of the lithium-ion battery under test. The current peak current test value is too large, and the battery terminal voltage rises too quickly. The peak current test value needs to be reduced, indicating that the current peak current test value does not meet the peak power calculation conditions of the lithium-ion battery under test in the second state of charge.

[0072] Therefore, for the charging test, after the lithium-ion battery under test has undergone a charging test for a preset time, the battery terminal voltage measured during the charging test must fall within the preset qualified charging voltage range (i.e., ...). )), The preset charging voltage threshold, The preset charging cutoff voltage for the lithium-ion battery under test. for The safety redundancy voltage reserved below ensures that the peak current test value meets the peak power calculation conditions of the lithium-ion battery under test in the second state of charge only when the actual charging time of the charging test reaches the preset time and the battery terminal voltage falls within the qualified charging voltage range at the end.

[0073] S5: Determine the peak current test value as the qualified peak current value of the lithium-ion battery under test in the second state of charge, and calculate the peak power of the lithium-ion battery under test in the second state of charge based on the peak current test value.

[0074] In one or more embodiments of this specification, if the battery terminal voltage falls within a preset acceptable voltage range and the actual pulse duration reaches the preset time, it indicates that the peak current test value meets the peak power calculation conditions for the lithium-ion battery under test in the second state of charge. Therefore, the peak current test value can be determined as the acceptable peak current value for the lithium-ion battery under test in the second state of charge. Based on the peak current test value, the peak power of the lithium-ion battery under test in the second state of charge is calculated. The peak power of the lithium-ion battery under test in the second state of charge can be determined by multiplying the peak current test value by the battery terminal voltage at the end of the test.

[0075] S6: Based on the battery terminal voltage, the actual pulse duration, and the peak current test value, determine the peak current test value for the next current pulse test, and repeat steps S3 to S6 until the peak current qualification value of the lithium-ion battery under test in the second state of charge is obtained, and calculate the peak power of the lithium-ion battery under test based on the peak current qualification value in the second state of charge.

[0076] In one or more embodiments of this specification, if the peak current test value does not meet the peak power calculation conditions of the lithium-ion battery under test in the second state of charge, it is necessary to determine the peak current test value of the next current pulse test based on the battery terminal voltage, the actual pulse duration, and the peak current test value, and repeat S3 to S6 until the battery terminal voltage falls into the preset voltage qualification range at the end of a certain current pulse test, and whether the actual pulse duration reaches the preset time, to obtain the peak current qualification value of the lithium-ion battery under test in the second state of charge. Then, based on the peak current test value that meets the peak power calculation conditions (i.e., the peak current qualification value in the second state of charge), the peak power of the lithium-ion battery under test in the second state of charge is calculated. At this time, S3 to S6 are no longer repeated, and the cycle terminates.

[0077] In one or more embodiments of this specification, the current pulse test is a discharge test of the lithium-ion battery under test. When the preset voltage qualification range is the discharge voltage qualification range, the method for determining the peak current test value of the next current pulse test based on the battery terminal voltage, the actual pulse duration, and the peak current test value can be as follows: if the battery terminal voltage of the lithium-ion battery under test does not fall into the discharge voltage qualification range, it can be determined whether the battery terminal voltage is within a preset first voltage range. This first voltage range can be between the discharge voltage threshold and the battery open-circuit voltage of the lithium-ion battery before discharge. For example, the first voltage range can be... If the battery terminal voltage is within the first voltage range, it means that the battery terminal voltage is not far from the qualified discharge voltage range.

[0078] If the battery terminal voltage is within a preset first voltage range, the first voltage adjustment parameter can be determined based on the battery open-circuit voltage before discharge, the battery terminal voltage after the current discharge test, and the discharge cutoff voltage of the lithium-ion battery under test. Then, based on the first voltage adjustment parameter, the preset redundancy voltage, and the discharge cutoff voltage, the first desired voltage for the next discharge test is determined. Finally, based on the peak current test value of the current discharge test, the first desired voltage, the battery open-circuit voltage, and the battery terminal voltage after the current discharge test, the peak current test value for the next discharge test can be determined.

[0079] If the battery terminal voltage is not within the preset first voltage range, the second expected voltage for the next discharge test can be determined based on the preset second voltage adjustment parameters, the preset redundancy voltage, and the discharge cutoff voltage. Then, based on the second expected voltage, the battery open-circuit voltage, the battery terminal voltage after the current discharge test, and the peak current test value of the current discharge test, the peak current test value for the next discharge test can be determined.

[0080] Provided that the terminal voltage of the lithium-ion battery under test is not less than the preset discharge voltage threshold, the formula for calculating the peak current value of the next discharge test is as follows:

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] in, This is the peak current test value for the next discharge test. The preset time for the discharge test (i.e., the target discharge time). This is the peak current test value of the current discharge test. This is the actual pulse duration (i.e., the actual discharge time of the current discharge test). The open-circuit voltage of the lithium-ion battery under test before discharge is given. The discharge cutoff voltage of the lithium-ion battery under test is _____. This is the preset redundant voltage. This is the battery terminal voltage. and These are all intermediate calculation coefficients, based on It can be determined and The corresponding specific voltage regulation parameters and desired voltages. This is the first voltage regulation parameter. This is the first desired voltage. The preset second voltage adjustment parameter, This is the second desired voltage. This is the preset first voltage range. The preset second voltage adjustment parameter can also be a value less than 0.

[0088] In one or more embodiments of this specification, when the current pulse test is a discharge test of the lithium-ion battery under test and the actual pulse duration is the actual discharge time of the discharge test, the method for determining the peak current test value of the next current pulse test based on the battery terminal voltage, the actual pulse duration and the peak current test value can also be to determine whether the actual discharge time is within the preset first time interval when the actual discharge time of the current discharge test of the lithium-ion battery under test is less than the preset time (i.e. the target discharge time originally set for the discharge test).

[0089] If so, the third voltage adjustment parameter can be determined based on the actual discharge time and the preset time. Then, based on the third voltage adjustment parameter, the preset redundant voltage, and the discharge cutoff voltage of the lithium-ion battery under test, the third expected voltage for the next discharge test can be determined. Finally, based on the peak current test value of the current discharge test, the third expected voltage, the open-circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage after the current discharge test, the peak current test value for the next discharge test can be determined.

[0090] If not, the fourth desired voltage for the next discharge test can be determined based on the preset fourth voltage adjustment parameter, the preset redundancy voltage, and the discharge cutoff voltage of the lithium-ion battery under test. Then, based on the peak current test value of the current discharge test, the fourth desired voltage, the open-circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage after the current discharge test, the peak current test value for the next discharge test can be determined.

[0091] If the actual discharge time of the lithium-ion battery under test is less than the preset time, the formula for calculating the peak current value of the next discharge test is as follows:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098] in, This is the peak current test value of the current discharge test. This represents the actual discharge time of the current discharge test. The preset time is the target discharge time originally set for the discharge test. This is the peak current test value for the next discharge test. The open-circuit voltage of the lithium-ion battery under test before discharge is given. The discharge cutoff voltage of the lithium-ion battery under test is _____. This is the preset redundant voltage. This is the battery terminal voltage after the current discharge test has ended. and These are all intermediate calculation coefficients, based on actual discharge time. It can be determined and The corresponding specific voltage regulation parameters and desired voltages. This is the third voltage regulation parameter. This is the third desired voltage. The preset fourth voltage adjustment parameter, This is the fourth desired voltage. This is the preset first time interval. The preset fourth voltage adjustment parameter can also be a value greater than 1.2.

[0099] In one or more embodiments of this specification, the current pulse test is a charging test of the lithium-ion battery under test. When the preset voltage qualified range is the charging voltage qualified range, the method to determine the peak current test value of the next current pulse test based on the battery terminal voltage, the actual pulse duration and the peak current test value can be to determine whether the battery terminal voltage is within the preset second voltage range when the battery terminal voltage at the end of the current charging test does not fall into the charging voltage qualified range.

[0100] If so, the fifth voltage adjustment parameter can be determined based on the battery open-circuit voltage before charging, the battery terminal voltage, and the charging cut-off voltage of the lithium-ion battery under test. Then, based on the fifth voltage adjustment parameter, the preset redundancy voltage, and the charging cut-off voltage, the fifth desired voltage for the next charging test can be determined. Finally, based on the peak current test value of the current charging test, the fifth desired voltage, the battery open-circuit voltage, and the battery terminal voltage, the peak current test value for the next charging test can be determined.

[0101] If not, the sixth desired voltage for the next charging test can be determined based on the preset sixth voltage adjustment parameters, the preset redundant voltage, and the charging cutoff voltage. Then, based on the sixth desired voltage, the battery open-circuit voltage, the battery terminal voltage, and the peak current test value of the current charging test, the peak current test value for the next charging test can be determined.

[0102] If the battery terminal voltage at the end of the current charging test is not greater than the preset charging voltage threshold, the formula for calculating the peak current test value of the next charging test is:

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] in, This will be the peak current test value for the next charging test. The preset time for the charging test (i.e., the target charging time). This is the peak current test value for the current charging test. This is the actual pulse duration (i.e., the actual charging time of the current charging test). The open-circuit voltage of the lithium-ion battery under test before charging. This represents the charging cutoff voltage of the lithium-ion battery under test. This is the preset redundant voltage. This is the battery terminal voltage after the current charging test has ended. and These are all intermediate calculation coefficients, based on It can be determined and The corresponding specific voltage regulation parameters and desired voltages. This is the fifth voltage regulation parameter. This is the fifth desired voltage. The preset sixth voltage adjustment parameter, This is the sixth desired voltage. This is the preset second voltage range. The preset sixth voltage adjustment parameter can also be a value less than 0.

[0110] In one or more embodiments of this specification, when the current pulse test is a charging test of the lithium-ion battery under test and the actual pulse duration is the actual charging time of the charging test, the method for determining the peak current test value of the next current pulse test based on the battery terminal voltage, the actual pulse duration and the peak current test value can also be to determine whether the actual charging time is within a preset second time interval when the actual charging time of the current charging test of the lithium-ion battery under test is less than a preset time (i.e., the target charging time originally set for the charging test).

[0111] If so, the seventh voltage adjustment parameter can be determined based on the actual charging time and the preset time. Then, based on the seventh voltage adjustment parameter, the preset redundant voltage, and the charging cutoff voltage of the lithium-ion battery under test, the seventh expected voltage for the next charging test can be determined. Finally, based on the peak current test value of the current charging test, the seventh expected voltage, the open-circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage after the current charging test, the peak current test value for the next charging test can be determined.

[0112] If not, the eighth desired voltage for the next charging test can be determined based on the preset eighth voltage adjustment parameters, the preset redundant voltage, and the charging cutoff voltage. The peak current test value for the next charging test is determined based on the peak current test value of the current charging test, the eighth desired voltage, the battery open-circuit voltage, and the battery terminal voltage after the current charging test ends.

[0113] If the actual charging time of the lithium-ion battery under test is less than the preset time (i.e., the target charging time originally set for the charging test), the calculation expression for the peak current test value of the next charging test is as follows:

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] in, This is the peak current test value for the current charging test. This represents the actual charging time during the current charging test. The preset time is the target charging time originally set for the charging test. This is the peak current test value for the next charging test. The open-circuit voltage of the lithium-ion battery under test before charging. This represents the charging cutoff voltage of the lithium-ion battery under test. This is the preset redundant voltage. This is the battery terminal voltage after the current charging test has ended. and These are all intermediate calculation coefficients, based on actual discharge time. It can be determined and The corresponding specific voltage regulation parameters and desired voltages. This is the seventh voltage regulation parameter. This is the seventh desired voltage. The preset eighth voltage adjustment parameter, This is the eighth desired voltage. This is the preset second time interval. The preset eighth voltage adjustment parameter can also be a value greater than 1.2.

[0121] based on Figure 1This paper presents a peak power testing method for lithium-ion batteries. This method constructs an efficient, universal, and stable automated peak power testing approach, transforming reliance on experience, complex models, or historical data into utilization of the battery's own physical characteristics and dynamic measured feedback. It achieves a good balance between improving efficiency and ensuring accuracy and safety. By utilizing the known acceptable peak current value at high SOC, the initial peak current test value at low SOC is calculated, making the initial test current very close to the true value. This significantly reduces the number of subsequent iterations from S3 to S6, transforming the lithium-ion battery peak power testing process from "repeated trial and error" to "precise prediction + a few verifications," significantly shortening the total testing time for a single SOC point and even the entire SOC range. This method is also applicable to brand-new batteries, aged batteries, or batteries with incomplete data, greatly improving the universality and ease of use of the testing method. Only a conservative initial value based on specifications or experience is needed to start, eliminating the need for any complex pre-test characteristics or historical data tables. The judgment and adjustment logic in step S6 does not preset a fixed voltage target value. Instead, it dynamically determines the adjustment target based on the actual deviation of the voltage or time measured in the previous test. This mechanism of "larger deviation, larger adjustment; smaller deviation, finer adjustment" fundamentally eliminates mechanical over-adjustment, making the iteration process more intelligent and stable. It can stably converge to the final peak current and peak power, avoiding oscillations around the true value. The peak power finally confirmed in step S5 is based on real physical test results, not indirect calculations from any model. Because the initial prediction is accurate and the correction process is stable, the final converged result can truly reflect the battery's limit capability under any state of charge.

[0122] This specification provides exemplary examples of measured results for two lithium iron phosphate batteries.

[0123] Example 1: Sample: A square lithium iron phosphate battery with a rated capacity of 132Ah.

[0124] Test conditions: 25℃ pulse discharge (preset target discharge time T=10s, 15s, 30s), U aim =2.5V, ΔU=150mV.

[0125] A specific voltage range [2.65V, 2.70V] (i.e., the first voltage range), and a specific pulse time range [4 / 5T, T] (i.e., the first time range).

[0126] Given initial current values ​​at 100%: 10s-15c=1980A, 15s-12c=1584A, 30s-10c=1320A.

[0127] The estimation coefficient σ is taken from the values ​​in Table 1 below (all values ​​are calculated based on the measured values ​​of the previous SOC point to determine the next SOC point): Table 1. Estimation Coefficient Values

[0128] Test results: The initial peak current prediction accuracy was 55.6% (25 / 45), the peak current accuracy after one iteration was 100%, and the average number of tests per test point was 1.4 (65 / 45). The test results are shown in Table 2 below.

[0129] Table 2. Discharge test results

[0130] Example 2: Sample: A square lithium iron phosphate battery with a rated capacity of 132Ah.

[0131] Test conditions: 0℃ pulse discharge (preset target discharge time T=10s, 15s, 30s), U aim =2.5V, ΔU=150mV.

[0132] A specific voltage range [2.65V, 2.70V] (i.e., the first voltage range), and a specific pulse time range [4 / 5T, T] (i.e., the first time range).

[0133] Given initial current values ​​at 100% SOC: 10s-15c=1980A, 15s-12c=1584A, 30s-10c=1320A.

[0134] The estimation coefficient σ is taken from the values ​​in Table 3 below (all values ​​are calculated based on the measured values ​​of the previous SOC point to determine the next SOC point): Table 3. Estimation Coefficient Values ​​(Table 2)

[0135] Test results: The initial peak current prediction accuracy was 75.6% (34 / 45), the peak current accuracy after one iteration was 78.6% (11 / 14), and the average number of tests per test point was 1.4 (63 / 45). The test results are shown in Table 4 below.

[0136] Table 4. Discharge Test Results (Part 2)

[0137] Example 3: Sample: A square lithium iron phosphate battery with a rated capacity of 102Ah.

[0138] Test conditions: 25℃ pulse discharge (preset target discharge time T=10s, 15s, 30s), Uaim =2.5V, ΔU=150mV.

[0139] A specific voltage range [2.65V, 2.70V] (i.e., the first voltage range), and a specific pulse time range [4 / 5T, T] (i.e., the first time range).

[0140] Given initial current values ​​at 100% SOC: 10s-15c=1530A, 15s-12c=1224A, 30s-10c=1020A; The estimation coefficient σ is taken from the values ​​in Table 5 below (all values ​​are calculated based on the measured values ​​of the previous SOC point to determine the next SOC point): Table 5. Estimation coefficient values ​​(Table 3)

[0141] Test results: The initial peak current prediction accuracy was 51.1% (23 / 45), the peak current accuracy after one iteration was 90.5% (19 / 21), and the average number of tests per test point was 1.6 (71 / 45). The test results are shown in Table 6 below.

[0142] Table 6. Discharge Test Results (Part 3)

[0143] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0144] The above description is merely an embodiment of this specification and is not intended to limit this specification. Various modifications and variations can be made to this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of the claims of this specification.

Claims

1. A method for testing the peak power of a lithium-ion battery, characterized in that, include: S1. Obtain the peak current qualification value of the lithium-ion battery under test in the first state of charge; S2. Based on the peak current qualification value of the lithium-ion battery under test in the first state of charge, determine the peak current test value of the lithium-ion battery under test in the second state of charge, wherein the remaining battery capacity represented by the first state of charge is greater than the remaining battery capacity represented by the second state of charge. S3. Based on the peak current test value, perform a current pulse test on the lithium-ion battery under test in the second state of charge for a preset time to determine the battery terminal voltage and actual pulse duration at the end of the test. S4. Determine whether the battery terminal voltage falls within a preset qualified voltage range, and whether the actual pulse duration reaches the preset time; S5. If both are yes, then the peak current test value is determined to be the peak current qualification value of the lithium-ion battery under test in the second state of charge, and the peak power of the lithium-ion battery under test is calculated based on the peak current test value. S6. If any of them are not true, then based on the battery terminal voltage, the actual pulse duration and the peak current test value, determine the peak current test value for the next current pulse test, and repeat steps S3 to S6 until the peak current qualification value of the lithium-ion battery under test in the second state of charge is obtained, and calculate the peak power of the lithium-ion battery under test based on the peak current qualification value in the second state of charge.

2. The method for testing the peak power of a lithium-ion battery as described in claim 1, characterized in that, The calculation expression for determining the peak current test value in S2 is: in, The peak current test value of the lithium-ion battery under test during the first current pulse test in the second state of charge. The lithium-ion battery under test has undergone the first state of charge. The peak current qualification value obtained after the current pulse test; , , These represent the percentage of remaining battery capacity of the lithium-ion battery under test. These are the preset estimation coefficients.

3. The method for testing the peak power of a lithium-ion battery as described in claim 1, characterized in that, The current pulse test is a discharge test of the lithium-ion battery under test; the preset voltage qualified range is the discharge voltage qualified range. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the battery terminal voltage does not fall within the qualified discharge voltage range, determine whether the battery terminal voltage is within a preset first voltage range. If so, then based on the open-circuit voltage of the lithium-ion battery before discharge, the battery terminal voltage, and the discharge cutoff voltage of the lithium-ion battery under test, a first voltage adjustment parameter is determined; based on the first voltage adjustment parameter, a preset redundant voltage, and the discharge cutoff voltage, a first expected voltage for the next discharge test is determined; based on the peak current test value, the first expected voltage, the battery open-circuit voltage, and the battery terminal voltage, the peak current test value for the next discharge test is determined. If not, then the second expected voltage for the next discharge test is determined based on the preset second voltage adjustment parameter, the redundant voltage, and the discharge cutoff voltage; the peak current test value for the next discharge test is determined based on the second expected voltage, the battery open circuit voltage, the battery terminal voltage, and the peak current test value.

4. The method for testing the peak power of a lithium-ion battery as described in claim 3, characterized in that, The formula for calculating the peak current value of the next discharge test is: in, This is the peak current test value for the next discharge test. For the preset time, The peak current test value of the current discharge test. The actual pulse duration, The open-circuit voltage of the lithium-ion battery under test before discharge is given. This is the discharge cutoff voltage of the lithium-ion battery under test. This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the first voltage regulation parameter. The first desired voltage; The preset second voltage adjustment parameter, The second desired voltage; This is the preset first voltage range.

5. The method for testing the peak power of a lithium-ion battery as described in claim 1, characterized in that, The current pulse test is a discharge test of the lithium-ion battery under test; the actual pulse duration is the actual discharge time of the discharge test. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the actual discharge time of the lithium-ion battery under test is less than the preset time, determine whether the actual discharge time is within the preset first time interval. If so, then based on the actual discharge time and the preset time, a third voltage adjustment parameter is determined; based on the third voltage adjustment parameter, the preset redundant voltage, and the discharge cutoff voltage of the lithium-ion battery under test, a third expected voltage for the next discharge test is determined; based on the peak current test value, the third expected voltage, the battery open-circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage, a peak current test value for the next discharge test is determined. If not, then the fourth desired voltage for the next discharge test is determined based on the preset fourth voltage adjustment parameter, the redundant voltage, and the discharge cutoff voltage; the peak current test value for the next discharge test is determined based on the peak current test value, the fourth desired voltage, the battery open circuit voltage, and the battery terminal voltage.

6. The method for testing the peak power of a lithium-ion battery as described in claim 5, characterized in that, The formula for calculating the peak current value of the next discharge test is: in, The peak current test value of the current discharge test. This refers to the actual discharge time of the current discharge test; The preset time; This is the peak current test value for the next discharge test; The open-circuit voltage of the lithium-ion battery under test before discharge is given. This is the discharge cutoff voltage of the lithium-ion battery under test. This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the third voltage regulation parameter. The third desired voltage; The preset fourth voltage adjustment parameter, The fourth desired voltage; This is the preset first time interval.

7. The method for testing the peak power of a lithium-ion battery as described in claim 1, characterized in that, The current pulse test is a charging test of the lithium-ion battery under test; the preset voltage qualification range is the charging voltage qualification range. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the battery terminal voltage does not fall within the qualified charging voltage range, determine whether the battery terminal voltage is within a preset second voltage range; If so, then based on the open-circuit voltage of the lithium-ion battery before charging, the battery terminal voltage, and the charging cutoff voltage of the lithium-ion battery under test, a fifth voltage adjustment parameter is determined; based on the fifth voltage adjustment parameter, a preset redundant voltage, and the charging cutoff voltage, a fifth desired voltage for the next charging test is determined; based on the peak current test value, the fifth desired voltage, the battery open-circuit voltage, and the battery terminal voltage, the peak current test value for the next charging test is determined. If not, then the sixth expected voltage for the next charging test is determined based on the preset sixth voltage adjustment parameter, the redundant voltage, and the charging cutoff voltage; the peak current test value for the next charging test is determined based on the sixth expected voltage, the battery open circuit voltage, the battery terminal voltage, and the peak current test value.

8. The method for testing the peak power of a lithium-ion battery as described in claim 7, characterized in that, The formula for calculating the peak current value of the next charging test is: in, This will be the peak current test value for the next charging test. For the preset time, The peak current test value for the current charging test. The actual pulse duration, The open-circuit voltage of the lithium-ion battery under test before charging. The charging cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the fifth voltage regulation parameter. The fifth desired voltage; The preset sixth voltage adjustment parameter, The sixth desired voltage; This is the preset second voltage range.

9. The method for testing the peak power of a lithium-ion battery as described in claim 1, characterized in that, The current pulse test is a charging test of the lithium-ion battery under test; the actual pulse duration is the actual charging time of the charging test. In step S6, based on the battery terminal voltage, the actual pulse duration, and the peak current test value, the peak current test value for the next current pulse test is determined, specifically including: If the actual charging time of the lithium-ion battery under test is less than the preset time, determine whether the actual charging time is within the preset second time interval. If so, then the seventh voltage adjustment parameter is determined based on the actual charging time and the preset time; the seventh expected voltage for the next charging test is determined based on the seventh voltage adjustment parameter, the preset redundant voltage, and the charging cutoff voltage of the lithium-ion battery under test; the peak current test value for the next charging test is determined based on the peak current test value, the seventh expected voltage, the battery open circuit voltage of the lithium-ion battery under test before charging, and the battery terminal voltage. If not, the eighth expected voltage for the next charging test is determined based on the preset eighth voltage adjustment parameter, the redundant voltage, and the charging cutoff voltage; the peak current test value for the next charging test is determined based on the peak current test value, the eighth expected voltage, the battery open circuit voltage, and the battery terminal voltage.

10. A method for testing the peak power of a lithium-ion battery as described in claim 9, characterized in that, The formula for calculating the peak current value of the next charging test is: in, The peak current test value for the current charging test. This refers to the actual charging time during the current charging test. The preset time; The peak current test value for the next charging test; The open-circuit voltage of the lithium-ion battery under test before charging. The charging cutoff voltage of the lithium-ion battery under test is denoted as . This is the preset redundant voltage. The battery terminal voltage; and These are all intermediate calculation coefficients; This is the seventh voltage regulation parameter. The seventh desired voltage; The preset eighth voltage adjustment parameter, The eighth desired voltage; This is the preset second time interval.

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