A method for measuring the DC resistance of a high-power battery

Abstract

The present invention relates to a method for measuring the DC resistance of a high-power battery. The method comprises the following steps: (1) charging and discharging the battery to be measured with a current of XC to obtain the average capacity of the battery to be measured; (2) fully charging the battery to be measured with a current of XC; (3) discharging the battery to be measured with a current of XC and then allowing it to stand; (4) discharging the battery to be measured with a current of YC and then allowing it to stand; (5) discharging the battery to be measured; (6) repeating steps (4) and (5); (7) fully charging the battery to be measured with a current of XC; (8) discharging the battery to be measured with a current of XC and then allowing it to stand; (9) charging the battery to be measured with a current of nYC and then allowing it to stand; (10) discharging the battery to be measured; (11) repeating steps (9) and (10) to complete the measurement. The measurement method provided by the present invention is applicable to pulsed charging and discharging currents with a magnification of 3C or more.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium ion batteries and relates to a method for measuring the direct current resistance of a high-power battery. Background Art

[0002] Lithium-ion batteries are widely used today, primarily because they are rechargeable secondary batteries. Also known as rocking chair batteries, they rely on the back-and-forth movement of lithium ions between the positive and negative electrodes, enabling the intercalation and deintercalation of lithium ions. During charging, lithium ions are released from the positive electrode and embedded in the negative electrode through the electrolyte. During discharge, lithium ions are released from the negative electrode and embedded in the positive electrode through the electrolyte.

[0003] After years of development, lithium-ion batteries have become the focus of research and development due to their advantages such as no memory effect, light weight, high energy density, high voltage platform, low self-discharge rate, high output power and long cycle life.

[0004] As lithium-ion batteries are increasingly used in daily life, people's performance requirements for lithium-ion batteries are also getting higher and higher. The performance of lithium-ion batteries is mainly determined by the battery's voltage, capacity, internal resistance, power and cycle life. Among them, internal resistance is one of the important parameters for evaluating battery performance. Internal resistance can usually be divided into AC internal resistance (ACR) and DC internal resistance (DCR). AC internal resistance is the internal resistance value of the battery obtained by applying a fixed frequency and current to the battery, generally using a frequency of 1KHz and a current of 50mA, and then collecting the corresponding voltage. After rectification, filtering and other processing, the DC internal resistance is calculated according to formula (1). The battery is passed through a constant DC current for a short period of time (a few seconds, more than ten seconds or tens of seconds) through the test equipment, and the voltage at both ends of the battery is measured. The current battery internal resistance is calculated according to formula (1). AC internal resistance reflects the state of the battery when it is static, and DC internal resistance reflects the resistance encountered by the current flowing through the battery when the battery is working. The size of DC internal resistance can directly reflect the performance of the battery when it is working, and is often used to reflect the degree of battery attenuation.

[0005] R=V / I Formula (1)

[0006] In the "Battey Test Manual For Plug-In Hybrid Electric Vehicles", a plug-in hybrid vehicle battery test manual published in 2014, the specific test method for DC internal resistance, HPPC (Hybrid Pulse Power Characterization), is described. The purpose of the HPPC test is to evaluate the dynamic power capabilities of the battery pack under current pulse conditions, including 10-second charging power and 10-second discharging power. Additionally, by processing the current-voltage curves of the HPPC test data, the relationship between the DC internal resistance and SOC of the battery can be obtained; meanwhile, this method can also be used to evaluate the degree of battery aging in the battery aging test.

[0007] The specific test method of HPPC is as follows: Apply a 10-second determined pulse discharge current and pulse charging current to the battery every 10% SOC, and calculate the charge-discharge DC internal resistance and power.

[0008] Among them, SOC (state of charge) refers to the state of charge of the battery, which is the ratio of the remaining capacity of the battery after being used for a period of time or left unused for a long time to the capacity in its fully charged state, usually expressed as a percentage, with a value range of 0 to 1. When SOC = 0, it means the battery is completely discharged, and when SOC = 1, it means the battery is fully charged.

[0009] However, it is found in actual use that for small-rate (≤5C) pulse charge-discharge batteries (energy-type batteries), this test method has a high accuracy; but for large-rate (such as 50C) pulse charge-discharge batteries (power-type batteries), if this method continues to be used to test the DC internal resistance, the 10s pulse discharge or charge will cause a large deviation in the current SOC state of the battery. For example: after the battery undergoes a 60C&10s pulse discharge, the battery SOC will decrease by 60C * 10s / 3600s = 16.7%, resulting in a large difference in the SOC of the battery during the current pulse charge and discharge, and the actual test results will have serious deviations.

[0010] In view of the above defects, there is no publicly available effective and appropriate improvement method. How to accurately measure the DC resistance of large-rate pulse charge-discharge batteries is a technical problem that urgently needs to be solved in the field of lithium-ion battery technology. Summary of the Invention

[0011] To solve the above technical problems, the present invention provides a method for measuring high-power DC resistance, which precisely controls the SOC value of the high-power battery after pulse charge and discharge, and further improves the accuracy of the SOC value of the high-power battery by separating the processes of pulse discharge and pulse charge into two cycles.

[0012] To achieve this goal, the present invention adopts the following technical solutions:

[0013] The present invention provides a method for measuring the DC resistance of a high-power battery, and the method includes the following steps:

[0014] (1) Charge and discharge the high-power battery to be measured with a current of XC to obtain the average capacity of the high-power battery to be measured;

[0015] (2) Charge the high-power battery to be measured to full capacity with a current of XC;

[0016] (3) Discharge the high-power battery to be measured with a current of XC and then let it stand;

[0017] (4) Discharge the high-power battery to be measured with a current of YC and then let it stand;

[0018] (5) Discharge the high-power battery to be measured;

[0019] (6) Repeat steps (4) and (5);

[0020] (7) Charge the high-power battery to be measured to full capacity with a current of XC;

[0021] (8) Discharge the high-power battery to be measured with a current of XC and then let it stand;

[0022] (9) Charge the high-power battery to be measured with a current of nYC and then let it stand;

[0023] (10) Discharge the high-power battery to be measured;

[0024] (11) Repeat steps (9) and (10) to complete the measurement of the DC resistance of the high-power battery;

[0025] Wherein, X ≤ 1, and X < Y, n ≠ 0.

[0026] The method provided by the present invention is an improvement on the original HPPC test method. First, complete the cycle of pulse discharge, adjust the discharge amount during the process to accurately control the SOC value, then complete the cycle of pulse charging after being fully charged, and also accurately control the SOC value by adjusting the discharge amount. The method accurately controls the SOC value of the high-power battery after pulse charge and discharge, and further improves the accuracy of the SOC value of the high-power battery by separating the process of pulse discharge and pulse charging into two cycles.

[0027] The method provided by the present invention performs pulse discharge first and then pulse charging because at the highest test point SOC (for example, 95% SOC), if pulse charging is performed first, it is very likely to cause overcharging of the battery and exceed the battery charging cut-off voltage. If a safety cut-off voltage is set, it may lead to insufficient high-current pulse charging time and incorrect final test results. Therefore, performing pulse discharge first and then pulse charging will not cause overcharging.

[0028] X≤1, for example, it can be 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 0.9, 0.95 or 1, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0029] The current of the YC of the present invention is a large current at least greater than 1C, which realizes pulse charging and discharging of high-power batteries.

[0030] Preferably, the number of charge and discharge cycles in step (1) is 2-5 times, for example, 2 times, 3 times, 4 times or 5 times, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0031] Preferably, the discharge capacity in step (3) is 5-20% SOC, for example, 5% SOC, 10% SOC, 12% SOC, 15% SOC or 20% SOC, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0032] Preferably, the standing time in step (3) is 0.8-1.2 h, for example, 0.8 h, 0.9 h, 1 h, 1.1 h or 1.2 h, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0033] Preferably, the discharge time in step (4) is 5-20s, for example, 5s, 8s, 10s, 12s, 15s or 20s, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0034] Preferably, the standing time in step (4) is 5-20 min, for example, 5 min, 8 min, 10 min, 12 min, 15 min or 20 min, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0035] Preferably, the capacity of the discharge in step (5) is the capacity of the discharge in step (3) minus the capacity of the discharge in step (4).

[0036] Preferably, the discharge current in step (5) is XC.

[0037] Preferably, the number of repetitions in step (6) is 5 - 20 times. For example, it can be 5 times, 10 times, 12 times, 15 times or 20 times, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0038] Preferably, the discharge capacity in step (8) is 5 - 20% SOC. For example, it can be 5% SOC, 10% SOC, 12% SOC, 15% SOC or 20% SOC, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0039] Preferably, the standing time in step (8) is 0.8 - 1.2 h. For example, it can be 0.8 h, 0.9 h, 1 h, 1.1 h or 1.2 h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0040] Preferably, the charging time in step (9) is 5 - 20 s. For example, it can be 5 s, 8 s, 10 s, 12 s, 15 s or 20 s, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0041] Preferably, the standing time in step (9) is 5 - 20 min. For example, it can be 5 min, 8 min, 10 min, 12 min, 15 min or 20 min, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0042] Preferably, n in step (9) is less than 1. For example, it can be 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 0.9 or 0.95, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0043] For the method provided by the present invention, the current of the discharge pulse is greater than that of the charging pulse because for most current research and commercial mass-produced lithium batteries, the discharge design capacity of the battery is higher than the charging design capacity. Therefore, the current of the discharge pulse should be greater than that of the charging pulse, and the magnitude of the current is within the charge and discharge tolerance range of the battery, otherwise it may cause battery failure.

[0044] Preferably, the value of n in step (9) is 0.5 - 0.8. For example, it can be 0.5, 0.6, 0.7, 0.75 or 0.8, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0045] Preferably, the discharge capacity in step (10) is the sum of the discharge capacity in step (8) and the charging capacity in step (9).

[0046] Preferably, the current of the discharge in step (10) is XC.

[0047] Preferably, the number of repetitions in step (11) is 5 - 20 times. For example, it can be 5 times, 10 times, 12 times, 15 times or 20 times, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0048] Preferably, Y ≥ 3. For example, it can be 3, 5, 10, 20, 50 or 60, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0049] The measurement method provided by the present invention is applicable to pulsed charge and discharge currents with a magnification of 3C or more.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] (1) The method provided by the present invention is an improvement based on the original HPPC test method. First, complete the cycle of pulsed discharge, adjust the discharge amount during the process to precisely control the SOC value, then perform the cycle of pulsed charge after fully charging, and also precisely control the SOC value by adjusting the discharge amount. The method accurately controls the SOC value of the high-power battery after pulsed charge and discharge, and further improves the accuracy of the SOC value of the high-power battery by separating the processes of pulsed discharge and pulsed charge into two cycles.

[0052] (2) The measurement method provided by the present invention is applicable to pulsed charge and discharge currents with a magnification of 3C or more. Detailed Embodiments

[0053] To facilitate the understanding of the present invention, the following embodiments are listed. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0054] High-power battery to be tested: 8Ah ternary soft-pack lithium-ion battery for HEV.

[0055] Embodiment 1

[0056] This embodiment provides a method for measuring the DC resistance of a high-power battery. The method includes the following steps:

[0057] (1) Charge and discharge the high-power battery to be tested at a current of 1C for 3 times to obtain the average capacity of the high-power battery to be tested;

[0058] (2) Charge the high-power battery to be tested fully at a current of 1C;

[0059] (3) Discharge the high-power battery to be tested at a current of 1C, with the discharge capacity being 10% SOC, and let it stand for 1 h;

[0060] (4)Discharge the high-power battery under test at a current of 10 C for 10 s, and let it stand for 10 min;

[0061] (5)Discharge the high-power battery under test, and the discharge capacity is (10% SOC - 100 C / 3600);

[0062] (6)Repeat steps (4) and (5) 8 times to complete the pulse discharge cycle of the high-power battery at 90% SOC, 80% SOC, 70% SOC... 10% SOC;

[0063] (7)Charge the high-power battery under test to full charge at a current of 1 C;

[0064] (8)Discharge the high-power battery under test at a current of 1 C, and the discharge capacity is 10% SOC, and let it stand for 1 h;

[0065] (9)Charge the high-power battery under test at a current of 7.5 C for 10 s, and let it stand for 10 min;

[0066] (10)Discharge the high-power battery under test, and the discharge capacity is (10% SOC + 75 C / 3600);

[0067] (11)Repeat steps (9) and (10) 8 times to complete the pulse charge cycle of the high-power battery at 90% SOC, 80% SOC, 70% SOC... 10% SOC, and complete the measurement of the DC resistance of the high-power battery.

[0068] Example 2

[0069] This example provides a method for measuring the DC resistance of a high-power battery, and the method includes the following steps:

[0070] (1)Charge and discharge the high-power battery under test at a current of 0.5 C for 2 times to obtain the average capacity of the high-power battery under test;

[0071] (2)Charge the high-power battery under test to full charge at a current of 0.5 C;

[0072] (3)Discharge the high-power battery under test at a current of 0.5 C, and the discharge capacity is 5% SOC, and let it stand for 0.8 h;

[0073] (4)Discharge the high-power battery under test at a current of 3 C for 5 s, and let it stand for 5 min;

[0074] (5)Discharge the high-power battery under test, and the discharge capacity is (5% SOC - 15 C / 3600);

[0075] (6) Repeat steps (4) and (5) 18 times to complete the pulsed discharge cycle of the high-power battery at 95% SOC, 90% SOC, 85% SOC... 5% SOC;

[0076] (7) Charge the high-power battery to be tested to full capacity at a current of 0.5C;

[0077] (8) Discharge the high-power battery to be tested at a current of 0.5C, with a discharge capacity of 5% SOC, and let it stand for 0.8h;

[0078] (9) Charge the high-power battery to be tested at a current of 2.25C for 5s, and let it stand for 5min;

[0079] (10) Discharge the high-power battery to be tested, with a discharge capacity of (5% SOC + 11.25C / 3600);

[0080] (11) Repeat steps (9) and (10) 18 times for the pulsed charge cycle of the high-power battery at 95% SOC, 90% SOC, 85% SOC... 5% SOC, and complete the measurement of the DC resistance of the high-power battery.

[0081] Example 3

[0082] This example provides a method for measuring the DC resistance of a high-power battery, and the method includes the following steps:

[0083] (1) Charge and discharge the high-power battery to be tested 5 times at a current of 1C to obtain the average capacity of the high-power battery to be tested;

[0084] (2) Charge the high-power battery to be tested to full capacity at a current of 1C;

[0085] (3) Discharge the high-power battery to be tested at a current of 1C, with a discharge capacity of 20% SOC, and let it stand for 1.2h;

[0086] (4) Discharge the high-power battery to be tested at a current of 20C for 20s, and let it stand for 20min;

[0087] (5) Discharge the high-power battery to be tested, with a discharge capacity of (20% SOC - 400C / 3600);

[0088] (6) Repeat steps (4) and (5) 4 times to complete the pulsed discharge cycle of the high-power battery at 80% SOC, 60% SOC, 40% SOC, 20% SOC;

[0089] (7) Charge the high-power battery to be tested to full capacity at a current of 1C;

[0090] Discharge the high-power battery under test at a current of 1C, with the discharged capacity being 20% SOC, and let it stand for 1.2 h;

[0091] (9) Charge the high-power battery under test at a current of 15C for 20 s, and let it stand for 20 min;

[0092] (10) Discharge the high-power battery under test, with the discharged capacity being (20% SOC + 300C / 3600);

[0093] (11) Repeat steps (9) and (10) four times, and perform pulse charge cycles on the high-power battery at 80% SOC, 60% SOC, 40% SOC, and 20% SOC to complete the measurement of the DC resistance of the high-power battery.

[0094] Example 4

[0095] This example provides a method for measuring the DC resistance of a high-power battery. Except that the discharged capacity in step (5) is 10% SOC, the remaining process steps are the same as those in Example 1.

[0096] Example 5

[0097] This example provides a method for measuring the DC resistance of a high-power battery. Except that the discharged capacity in step (10) is 10% SOC, the remaining process steps are the same as those in Example 1.

[0098] Example 6

[0099] This example provides a method for measuring the DC resistance of a high-power battery. Except that Y = 50, the remaining process steps are the same as those in Example 1.

[0100] Example 7

[0101] This example provides a method for measuring the DC resistance of a high-power battery. Except that the charging current magnitude in step (9) is 10C and the discharged capacity in step (10) is (10% SOC + 100C / 3600), the remaining process steps are the same as those in Example 1.

[0102] Example 8

[0103] This example provides a method for measuring the DC resistance of a high-power battery. Except that the charging current magnitude in step (9) is 15C and the discharged capacity in step (10) is (10% SOC + 150C / 3600), the remaining process steps are the same as those in Example 1.

[0104] Comparative Example 1

[0105] This comparative example provides a method for measuring the DC resistance of a lithium-ion battery. The measurement method is the conventional HPPC test method, which includes the following steps:

[0106] (1) Charge and discharge the lithium-ion battery to be tested at a current of 1C three times to obtain the average capacity of the lithium-ion battery to be tested;

[0107] (2) Charge the lithium-ion battery to be tested to full capacity at a current of 1C;

[0108] (3) Discharge the lithium-ion battery to be tested at a current of 1C, and the discharge capacity is 10% SOC, then let it stand for 1h;

[0109] (4) Discharge the lithium-ion battery to be tested at a current of 3C for 10s and let it stand for 40s;

[0110] (5) Charge the lithium-ion battery to be tested at a current of 2.25C for 10s and let it stand for 10min;

[0111] (6) Repeat steps (3) to (5) eight times for the charge and discharge cycles of 90% SOC, 80% SOC, 70% SOC... 10% SOC to complete the measurement of the DC resistance of the lithium-ion battery.

[0112] Comparative Example 2

[0113] This comparative example provides a method for measuring the DC battery of a lithium-ion battery. Except that Y = 50, the other process steps are the same as those in Comparative Example 1.

[0114] Comparative Example 3

[0115] This comparative example provides a method for measuring the DC resistance of a high-power battery. The method includes the following steps:

[0116] (1) Charge and discharge the high-power battery to be tested at a current of 1C three times to obtain the average capacity of the high-power battery to be tested;

[0117] (2) Charge the high-power battery to be tested to full capacity at a current of 1C;

[0118] (3) Discharge the high-power battery to be tested at a current of 1C, and the discharge capacity is 10% SOC, then let it stand for 1h;

[0119] (4) Charge the high-power battery to be tested at a current of 7.5C for 10s and let it stand for 10min;

[0120] (5) Discharge the high-power battery to be tested, and the discharge capacity is (10% SOC + 75C / 3600);

[0121] (6) Repeat steps (4) and (5) eight times to complete the pulse charge and discharge cycles of the high-power battery at 90% SOC, 80% SOC, 70% SOC... 10% SOC;

[0122] (7) Charge the high-power battery to full capacity at a current of 1C;

[0123] (8) Discharge the high-power battery to be tested at a current of 1C, with a discharge capacity of 10% SOC, and let it stand for 1h;

[0124] (9) Discharge the high-power battery to be tested at a current of 10C for 10s, and let it stand for 10min;

[0125] (10) Discharge the high-power battery to be tested, with a discharge capacity of (10% SOC - 100C / 3600);

[0126] (11) Repeat steps (9) and (10) eight times for the pulse charge and discharge cycles of the high-power battery at 90% SOC, 80% SOC, 70% SOC... 10% SOC to complete the measurement of the DC resistance of the high-power battery.

[0127] The error analysis results of the above measurement process are shown in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] The following conclusions can be drawn from Table 1:

[0132] (1) From Examples 1-3 and Examples 6-8, it can be seen that the method provided by the present invention is an improvement on the original HPPC test method and is applicable to pulse charge and discharge currents of 3C and above. First, complete the pulse discharge cycle, adjust the discharge amount during the process to accurately control the SOC value, then perform the pulse charge cycle after fully charging, and also accurately control the SOC value by adjusting the discharge amount. The method accurately controls the SOC value of the high-power battery after pulse charge and discharge, and further improves the accuracy of the SOC value of the high-power battery by separating the pulse discharge and pulse charge processes into two cycles.

[0133] (2) From the comparison between Examples 4, 5 and Example 1, it can be seen that when the steps provided by the present invention are changed, it is impossible to accurately regulate the SOC value under pulse, and it cannot meet the pulse charge and discharge currents of 3C and above.

[0134] (3) From the comparison between Comparative Examples 1 and 2 and Examples 1 and 8, it can be seen that based on the original HPPC test method, the present invention realizes the measurement of the DC resistance of the pulse charge and discharge current at a magnification of 3C and above.

[0135] (4) From the comparison between Comparative Example 3 and Example 1, it can be seen that when pulse charging is performed first and then pulse discharging, it is impossible to accurately control the SOC value under the pulse, and it cannot meet the pulse charge and discharge current at a magnification of 3C and above.

[0136] In summary, the method provided by the present invention is an improvement based on the original HPPC test method and is applicable to the pulse charge and discharge current at a magnification of 3C and above. First, complete the cycle of pulse discharging, adjust the discharge amount during the process to accurately control the SOC value, then perform the cycle of pulse charging after fully charging, and also accurately control the SOC value by adjusting the discharge amount. The method accurately controls the SOC value of the high-power battery after pulse charge and discharge, and further improves the accuracy of the SOC value of the high-power battery by separating the processes of pulse discharging and pulse charging into two cycles.

[0137] The present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for measuring the DC resistance of a high-power battery, characterized in that, The method includes the following steps: (1) Charge and discharge the high-power battery to be tested at a current of XC to obtain the average capacity of the high-power battery to be tested; (2) Charge the high-power battery to be tested to full capacity at a current of XC; (3) Discharge the high-power battery to be tested at a current of XC and let it stand; (4) Discharge the high-power battery to be tested at a current of YC and let it stand; (5) Discharge the high-power battery to be tested, and the current of the discharge in step (5) is XC; (6) Repeat step (4) and step (5); (7) Charge the high-power battery to be tested to full capacity at a current of XC; (8) Discharge the high-power battery to be tested at a current of XC and let it stand; (9) Charge the high-power battery to be tested at a current of nYC and let it stand; (10) Discharge the high-power battery to be tested, and the current of the discharge in step (10) is XC; (11) Repeat step (9) and step (10) to complete the measurement of the DC resistance of the high-power battery; wherein, X ≤ 1, and X < Y, n ≠ 0; The discharge capacity in step (3) is 5-20% SOC; The standing time in step (3) is 0.8-1.2 h; The discharge time in step (4) is 5-20 s; The standing time in step (4) is 5-20 min; The discharge capacity in step (5) is the discharge capacity in step (3) minus the discharge capacity in step (4); The discharge capacity in step (8) is 5-20% SOC; The standing time in step (8) is 0.8-1.2 h; The charging time in step (9) is 5-20 s; The standing time in step (9) is 5-20 min; The discharge capacity in step (10) is the sum of the discharge capacity in step (8) and the charging capacity in step (9).

2. The method for measuring the DC resistance of a high-power battery according to claim 1, characterized in that, The number of charge and discharge times in step (1) is 2-5 times.

3. The method for the DC resistance of a high-power battery according to claim 1, characterized in that The number of repetitions in step (6) is 5- to 20 times.

4. The method for the DC resistance of a high-power battery according to any one of claims 1-3, characterized in that, n < 1 in step (9).

5. The method for the DC resistance of a high-power battery according to any one of claims 1 to 3, characterized in that The value of n in step (9) is 0.5-0.

8.

6. The method for the DC resistance of the high-power battery according to claim 5, characterized in that, The number of repetitions in step (11) is 5-20 times.

7. The method for high-power battery DC resistance according to claim 6, characterized in that, Y ≥ 3.

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