A method for quantitatively detecting internal short circuit resistance of a battery which is insensitive to aging and load

Abstract

The application provides a kind of battery internal short circuit resistance quantitative detection method insensitive to aging and load, belongs to lithium ion power battery fault detection technical field, including 1, by ampere-hour integration method calculates the SOC value of #j battery in k time in battery pack;2, voltage equalization algorithm with hysteresis is used, and two threshold values are set;3, under the condition that passive equalization and the SOC of battery pack remains unchanged before and after charge-discharge test, each relationship is calculated;4, under the condition that active equalization and the SOC of battery pack remains unchanged before and after charge-discharge test, each relationship is calculated;5, the relationship between internal short circuit leakage capacity and equalization capacity is summarized;6, according to Ohm's law, the internal short circuit resistance value is calculated from the leakage capacity.The method proposed in the application can realize the detection of internal short circuit battery and the calculation of internal short circuit resistance value under the condition that the equalization system is working, is suitable for any aging state and any operating condition of battery, and realizes the quantitative analysis of internal short circuit.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion power battery fault detection technology, and particularly to a quantitative detection method for the internal short-circuit resistance of a battery that is insensitive to aging and load. Background Technology

[0002] With the increasing utilization of lithium-ion batteries, thermal runaway events have become more frequent in recent years, drawing global attention to safety issues. In the absence of mechanical abuse such as collisions, internal short circuits (ISCs) are the primary cause of thermal runaway. When abnormal signals caused by ISCs (such as voltage drops or temperature rises) become apparent, there are no countermeasures to prevent battery fires. Therefore, early detection of ISCs has become a feasible alternative to improve battery safety. However, ISCs occur inside the battery, have multiple triggering factors, and undergo a long, complex, and insidious evolution process, making early prediction of ISCs technically challenging.

[0003] There are many methods for detecting ISC (Internal Short-Circuit Resistance) faults, which can be broadly categorized into qualitative and quantitative assessments. Qualitative assessment methods mainly include consistency-based, model-based, and data-driven approaches. These methods can detect and locate ISC-affected batteries, but they cannot identify the degree and severity of ISC faults, reducing the effectiveness and safety of battery maintenance. Therefore, it is necessary to quantitatively analyze the short-circuit resistance or leakage current inside the battery. Existing quantitative assessment methods are still immature, limited in scope, and have certain limitations, such as inability to handle aged batteries, high cost, or difficulty in application under complex operating conditions.

[0004] Therefore, developing a quantitative detection method for short circuits in battery packs under aging and complex operating conditions is of great importance to the safety of battery packs. Summary of the Invention

[0005] The purpose of this invention is to provide a method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, characterized by comprising the following steps:

[0006] S1: Calculate the SOC value of battery #j in the battery pack at time k using the ampere-hour integration method;

[0007] S2: The equalization system adopts a voltage equalization algorithm with hysteresis and sets two thresholds to prevent random errors in the voltage sampling process;

[0008] S3: Under the condition of passive balancing and the battery pack's SOC remains unchanged before and after the charge and discharge test, first derive the formula for calculating the balancing capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to the relationship between the balancing capacity and the short circuit leakage capacity under the condition of internal short circuit.

[0009] S4: Under the condition of active balancing and the battery pack SOC remains unchanged before and after the charge and discharge test, first derive the formula for calculating the balancing capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to the relationship between the balancing capacity and the short circuit leakage capacity under the condition of internal short circuit.

[0010] S5: Summarize the relationship between the internal short-circuit leakage capacity and the equalization capacity in a battery pack with internal short-circuit batteries under passive and active equalization strategies.

[0011] S6: Based on Ohm's law, the internal short-circuit resistance is calculated using leakage capacity, voltage data, and charge / discharge time, thus completing the quantitative detection of the internal short-circuit resistance of the battery, which is insensitive to aging and load.

[0012] Furthermore, in S1, the SOC is the ratio of the battery's remaining capacity to its actual capacity. The calculation process of S1 includes the battery's charge / discharge capacity and the battery's equalization capacity. The formula for calculating the SOC value of battery #j in the battery pack at time k is expressed as follows:

[0013]

[0014] Among them, I pack (τ) represents the current of the battery pack at time τ; Let Q be the equalization current of battery #j at time τ, its value referring to the manufacturer's recommended equalization current, and the current direction uniformly defined as positive for charging the battery; j ΔT represents the capacity of battery #j; ΔT represents the cycle time; Δt represents the balancing hardware operating time.

[0015] Furthermore, S2 specifically refers to the following: In the equalization system, the equalization strategy is based on the voltage hysteresis equalization algorithm, which prevents random errors in the voltage sampling process by setting two thresholds.

[0016] Furthermore, in S3, under the premise of perfect passive balancing and constant SOC before and after charging and discharging, the balancing capacity expressions for battery #j in the battery pack during charging and discharging stages are derived separately for the case without short circuit:

[0017]

[0018]

[0019] The equal capacity expression for battery #j before and after the entire charge and discharge process is as follows:

[0020]

[0021] The battery pack is charged during time k1-k2, increasing the State of Charge (SOC) from z1 to z2, and then discharged during time k2-k3, decreasing the SOC from z2 to z1; Q j The capacity of battery #j; and These represent the balanced capacity of battery #j during the charging and discharging stages, respectively, under passive balancing. To achieve balanced capacity throughout the entire charging and discharging phase, and and All are negative values.

[0022] Furthermore, in S3, under the premise that the battery pack is in a perfectly passively balanced state and the SOC remains unchanged before and after charging and discharging, the expressions for the balanced capacity during the charging and discharging stages when there is an internally short-circuited battery in the battery pack are derived from the case of no short circuit as follows:

[0023]

[0024]

[0025] Therefore, the equal capacity expression of battery #j before and after the entire charge and discharge process is as follows:

[0026]

[0027] The equalization capacity expression for a battery pack containing an internally short-circuited battery #1 is as follows:

[0028]

[0029] Therefore, the expression for the leakage capacity of internally short-circuited battery #1 before and after charging and discharging is:

[0030]

[0031] in, To balance the capacity throughout the entire charging and discharging phase. and These represent the leakage capacity of battery #j during the charging and discharging stages in a battery pack with an internal short circuit under passive equalization. The leakage capacity during the entire charge and discharge phase is set to a negative value; N is the number of batteries connected in series.

[0032] Furthermore, in S4, under the premise that the battery pack is in a perfectly active balanced state and the SOC remains unchanged before and after charging and discharging, the equalization capacity expressions for the charging and discharging stages of battery #j in the battery pack are derived from the non-short-circuit case as follows:

[0033]

[0034]

[0035] The equal capacity expression for battery #j before and after the entire charge and discharge process is obtained as follows:

[0036]

[0037] From the above formula, we can see that the battery pack is first charged during time k1-k2, and the SOC increases from z1 to z2. Then it is discharged during time k2-k3, and the SOC decreases from z2 to z1. and These represent the balanced capacity of battery #j during the charging and discharging phases, respectively, under active balancing. This is to balance the capacity throughout the entire charging and discharging phase.

[0038] Furthermore, in S4, under the premise that the battery pack is in a perfectly active balanced state and the SOC remains unchanged before and after charging and discharging, the equalization capacity expressions for the charging and discharging stages when there is an internal short-circuited battery in the battery pack are further derived from the non-short-circuit case as follows:

[0039]

[0040]

[0041] The equal capacity expression for battery #j before and after the entire charge and discharge process is obtained as follows:

[0042]

[0043] The analysis yielded an expression for the balanced capacity of battery #1, which has an internal short circuit in the battery pack, as follows:

[0044]

[0045] This leads to the expression for the leakage capacity of internally short-circuited battery #1 before and after charging and discharging, which is:

[0046]

[0047] In the above formula, and These represent the equalization capacity of battery #j in the internal short-circuit battery pack under active equalization during the charging and discharging stages. To balance the capacity throughout the entire charging and discharging phase. and These represent the leakage capacity of battery #j during the charging and discharging stages in an internally short-circuited battery pack under active balancing conditions. This refers to the leakage capacity during the entire charging and discharging phase.

[0048] Furthermore, in S5, the unified relationship between internal short-circuit leakage capacity and equalization capacity is expressed as:

[0049]

[0050] in, and These represent the balanced capacity and leakage capacity of battery #j in the internal short-circuit battery pack under the balanced strategy.

[0051] Furthermore, in S6, the formula for calculating the internal short-circuit resistance is expressed as follows:

[0052]

[0053] Among them, R isc V is the internal short-circuit resistance of the battery. l (k1:k3) represents the voltage sequence of battery #j at times k1-k3; k1 represents the leakage capacity of battery #j in the internal short-circuit battery pack during the charging and discharging process; k2 represents the start time of charging and discharging; and k3 represents the end time of charging and discharging.

[0054] Furthermore, the State of Charge (SOC) before discharge and after charging is the same; the equalization capacity is calculated using the equalization current ampere-hour integral method, and the equalization current adopts the classic value recommended by the manufacturer.

[0055] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0056] 1. The calculation method proposed in this invention does not depend on the equilibrium effect of the equilibrium system and is also applicable to non-ideal active equilibrium situations in reality.

[0057] 2. Compared with traditional quantitative analysis, the calculation method proposed in this invention has lower computational complexity, which is similar to that of the ampere-hour integration method, and can be applied online.

[0058] 3. Compared with traditional quantitative analysis, the calculation method proposed in this invention is not sensitive to the aging state and load file of the battery, and can be applied to vehicle data calculation.

[0059] 4. Compared with traditional quantitative analysis, the calculation method proposed in this invention has high accuracy in calculating the internal short-circuit resistance. Attached Figure Description

[0060] Figure 1 This is a flowchart of a method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, according to the present invention.

[0061] Figure 2 This is a diagram showing the balanced capacity trajectory of parallel batteries with four different short-circuit resistance values ​​in this invention. Detailed Implementation

[0062] The following is a more detailed description of a quantitative detection method for the internal short-circuit resistance of a battery that is insensitive to aging and load, with reference to schematic diagrams. Preferred embodiments of the invention are shown. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0063] like Figure 1 As shown, a method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load includes the following steps:

[0064] Step 1: First, define the state of the battery. SOH is the ratio of the battery's actual capacity to its nominal capacity, and SOC is the ratio of the battery's remaining capacity to its actual capacity.

[0065] Step 2: Calculate the SOC value of battery #j in the battery pack at time k using the ampere-hour integration method.

[0066] The SOC of battery #j in the battery pack at time k is calculated using the ampere-hour integration method. The calculation process includes the charge / discharge capacity of the battery pack and the equalization capacity of the batteries. Its expression is:

[0067]

[0068] In the formula, I pack (τ) represents the current of the battery pack at time τ. Let be the balancing current of battery #j at time τ. Its value is based on the balancing current recommended by the manufacturer. The current direction is uniformly defined as positive when charging the battery. Qj is the capacity of battery #j, ΔT is the cycle working time, and Δt is the working time of the balancing hardware.

[0069] Step 3: The equalization system adopts a voltage equalization algorithm with hysteresis and sets two thresholds to prevent random errors in the voltage sampling process.

[0070] The equalization strategy described in this method is based on a voltage hysteresis equalization algorithm. The algorithm sets two thresholds to prevent random errors during the voltage sampling process. The specific algorithm is shown in Table 1.

[0071]

[0072] Table 1

[0073] Step 4: Under ideal passive balancing and with the battery pack's SOC remaining unchanged before and after the charge and discharge test, first derive the formula for calculating the balanced capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to derive the relationship between the balanced capacity and the short circuit leakage capacity under the condition of a short circuit in a certain cell.

[0074] Under the premise of perfect passive balancing and constant SOC before and after charging and discharging, the balancing capacity expressions of battery #j in the battery pack during the charging and discharging stages are derived separately for the case without short circuit, and the balancing capacity expression of battery #j before and after the entire charging and discharging process is obtained. The expressions are as follows:

[0075]

[0076]

[0077]

[0078] In the formula, the battery pack is charged during time k1 to k2, and the SOC increases from z1 to z2. Then it is discharged during time k2 to k3, and the SOC decreases from z2 to z1. Qj is the capacity of battery #j. and These represent the balanced capacity of battery #j during the charging and discharging phases, respectively, under passive balancing. To achieve balanced capacity throughout the entire charging and discharging phase, and and All are negative values.

[0079] Under the premise of perfect passive balancing and constant SOC before and after charging and discharging, the balancing capacity expression of battery #j during charging and discharging is derived by further extending the calculation to the case of no short circuit:

[0080]

[0081]

[0082] And the expression for the balanced capacity of battery #j before and after the entire charge and discharge process is derived:

[0083]

[0084] The equalization capacity expression for a battery pack with an internal short-circuit battery #1 was also analyzed:

[0085]

[0086] Finally, the expression for the leakage capacity of the internally short-circuited battery #l before and after charging and discharging is obtained as follows:

[0087]

[0088] In the formula, the battery pack is charged during time k1 to k2, and the SOC increases from z1 to z2. Then it is discharged during time k2 to k3, and the SOC decreases from z2 to z1. Qj is the capacity of battery #j. and These represent the equalization capacity of battery #j in the internal short-circuit battery pack under passive equalization during the charging and discharging stages. To achieve balanced capacity throughout the entire charging and discharging phase, and and All are negative values. and These represent the leakage capacity of battery #j during the charging and discharging stages in a battery pack with an internal short circuit under passive equalization. The leakage capacity during the entire charging and discharging phase is also negative, and N is the number of batteries connected in series.

[0089] Step 5: Under the ideal active balancing condition and with the battery pack's SOC remaining unchanged before and after the charge and discharge test, first derive the formula for calculating the balancing capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to derive the relationship between the balancing capacity and the short circuit leakage capacity under the condition of a short circuit in a certain cell.

[0090] Under the premise of perfect active balancing and constant SOC before and after charging and discharging, the balancing capacity expressions for battery #j in the battery pack during the charging and discharging stages are derived separately for the case without short circuit, and the balancing capacity expression for battery #j before and after the entire charging and discharging process is obtained. The expressions are as follows:

[0091]

[0092]

[0093]

[0094] In the formula, the battery pack is charged during time k1 to k2, and the SOC increases from z1 to z2. Then it is discharged during time k2 to k3, and the SOC decreases from z2 to z1. Qj is the capacity of battery #j. and These represent the balanced capacity of battery #j during the charging and discharging phases, respectively, under active balancing. This is to balance the capacity throughout the entire charging and discharging phase.

[0095] Under the premise of perfect active balancing and constant SOC before and after charging and discharging, and without short circuit conditions, the balancing capacity expression of battery #j during charging and discharging is derived by further extending the derivation to the case where there is an internal short-circuited battery in the battery pack:

[0096]

[0097]

[0098] And the expression for the balanced capacity of battery #j before and after the entire charge and discharge process is derived:

[0099]

[0100] The equalization capacity expression for a battery #l with an internal short circuit in the battery pack was also analyzed:

[0101]

[0102] Finally, the expression for the leakage capacity of the internally short-circuited battery #l before and after charging and discharging is obtained as follows:

[0103]

[0104] In the formula, the battery pack is charged during time k1 to k2, and the SOC increases from z1 to z2. Then it is discharged during time k2 to k3, and the SOC decreases from z2 to z1. Qj is the capacity of battery #j. and These represent the equalization capacity of battery #j in the internal short-circuit battery pack under active equalization during the charging and discharging stages. To balance the capacity throughout the entire charging and discharging phase. and These represent the leakage capacity of battery #j during the charging and discharging stages in an internally short-circuited battery pack under active balancing conditions. The leakage capacity is denoted as N, where N is the number of batteries connected in series during the entire charging and discharging process.

[0105] Step 6: Summarize the relationship between the internal short-circuit leakage capacity and the equalization capacity in battery packs with internal short-circuit batteries under passive and active equalization strategies.

[0106] Based on active and passive balancing scenarios, a unified formula is derived for the relationship between the internal short-circuit leakage capacity and the balancing capacity in a battery pack with one internal short-circuit battery:

[0107]

[0108] In the formula, and These represent the balanced capacity and leakage capacity of battery #j in the internal short-circuit battery pack under the balanced strategy, respectively, and N is the number of batteries connected in series.

[0109] Step 7: Calculate the internal short-circuit resistance based on Ohm's law, using the leakage capacity, voltage data, and charge / discharge time.

[0110] According to Ohm's law, the internal short-circuit resistance can be calculated from the leakage capacity, voltage data, and charge / discharge time:

[0111]

[0112] In the formula, Risc is the internal short-circuit resistance of the battery, V l (k1:k3) represents the voltage sequence of battery #j at times k1 to k3, where ΔT is the periodic operating time. K1 represents the leakage capacity of battery #j in the internal short-circuit battery pack during the charging and discharging process, k1 represents the start time of charging and discharging, and k3 represents the end time of charging and discharging.

[0113] The technical solution of the present invention is further illustrated below through specific embodiments:

[0114] Step 1: Select 12 18650 batteries, connect them in parallel in pairs and then in series to form a small battery pack with 6 series and 2 parallel (6S2P) configurations. The capacity of each battery is shown in Table 2.

[0115]

[0116] Table 2

[0117] Step 2: Charge and discharge the battery pack using a charge / discharge tester. An external BMS board is connected to achieve real-time equalization control of the battery pack. The cycle time is 1000ms, including 800ms for the equalizer and 200ms for sampling, calculation, and communication. The equalization system uses a voltage equalization algorithm with hysteresis and sets two thresholds to prevent random errors during voltage sampling (see Table 1 above). Active or passive equalization is used depending on the requirements; passive equalization is used here. The battery with the highest voltage in the pack is directly discharged through resistance to achieve voltage equalization.

[0118] Step 3: Since the actual internal short circuit process of a battery is quite dangerous, for experimental safety, this example uses an external short-circuit resistor connected in parallel to the battery to simulate the internal short circuit of the battery, and different degrees of internal short circuit can be achieved by changing the resistance value.

[0119] Step 4: In this example, four resistors with different resistance values ​​are connected in parallel to simulate different degrees of internal short circuit. A random load condition is applied to the battery pack. The equalization capacity for all four cases is calculated according to the manufacturer's recommended equalization current. The results are as follows: Figure 2 , Figure 2 The internally short-circuited battery can be clearly identified. The resistance value calculated using the method of this invention is compared with the actual resistance value. The comparison results are shown in Table 3.

[0120]

[0121] Table 3

[0122] This embodiment provides a quantitative detection method for the internal short-circuit resistance of a battery that is insensitive to aging and load. It has lower computational complexity, is similar to that of the ampere-hour integration method, has high accuracy in calculating the internal short-circuit resistance, and is insensitive to the aging state and load conditions of the battery.

[0123] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, characterized in that, Includes the following steps: S1: Calculate the ampere-hour integration time of battery #j in the battery pack using the ampere-hour integration method. SOC value at time t; S2: The equalization system adopts a voltage equalization algorithm with hysteresis and sets two thresholds to prevent random errors in the voltage sampling process; S3: Under the condition of passive equalization and the SOC of the battery pack remains unchanged before and after the charge and discharge test, first derive the formula for calculating the equalization capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to the relationship between the equalization capacity and the short circuit leakage capacity under the condition of internal short circuit. S4: Under the condition of active balancing and the battery pack SOC remains unchanged before and after the charge and discharge test, first derive the formula for calculating the balancing capacity of the battery pack before and after the charge and discharge test without short circuit, and then extend it to the relationship between the balancing capacity and the short circuit leakage capacity under the condition of internal short circuit. S5: Summarize the relationship between the internal short-circuit leakage capacity and the equalization capacity in a battery pack with internal short-circuit batteries under passive and active equalization strategies. S6: Based on Ohm's law, the internal short-circuit resistance is calculated using leakage capacity, voltage data, and charge / discharge time, thus completing the quantitative detection of the internal short-circuit resistance of the battery, which is insensitive to aging and load. In S2, the voltage equalization algorithm with hysteresis is specifically as follows: ； In S5, the unified relationship between the internal short-circuit leakage capacity and the equalization capacity is expressed as: ； in, and These represent the balanced capacity and leakage capacity of battery #j in the internal short-circuit battery pack under the balanced strategy, respectively. This represents the number of batteries connected in series. In S6, the formula for calculating the internal short-circuit resistance is expressed as follows: ； in, This is the internal short-circuit resistance of the battery; For #j battery in time - Voltage sequence; The leakage capacity of battery #j in the internal short-circuit battery pack during the charging and discharging process; This is the start time of charging and discharging; This refers to the end time of the charge / discharge cycle; This refers to the periodic working time.

2. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 1, is characterized in that... In S1, SOC is the ratio of the battery's remaining capacity to its actual capacity. The calculation process of S1 includes the battery's charge / discharge capacity and the battery's equalization capacity. In the battery pack, battery #j... The formula for calculating the SOC value at time t is expressed as: ； in, For battery pack in time The current; For #j battery in time The equalization current is set according to the manufacturer's recommended equalization current, and the current direction is uniformly defined as positive for charging the battery. The capacity of battery #j; The working time is the periodic time; To balance hardware workload.

3. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 1, is characterized in that... In S3, under the premise that the battery pack is in a perfectly passively balanced state and the SOC remains unchanged before and after charging and discharging, the balanced capacity expressions for the charging and discharging stages of battery #j in the battery pack are derived separately under the condition of no short circuit: ； ； The equal capacity expression for battery #j before and after the entire charge and discharge process is as follows: ； The battery pack in time - Charging, SOC by Increase to Then in time - Discharge, SOC from Reduce to ; The capacity of battery #j; and These represent the balanced capacity of battery #j during the charging and discharging stages, respectively, under passive balancing. To achieve balanced capacity throughout the entire charging and discharging phase, and , and All are negative values.

4. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 3, is characterized in that... In S3, under the premise that the battery pack is in a perfectly passively balanced state and the SOC remains unchanged before and after charging and discharging, the equalization capacity expressions for the charging and discharging stages when there is an internally short-circuited battery in the battery pack are further derived from the non-short-circuit scenario as follows: ； ； Therefore, the equal capacity expression of battery #j before and after the entire charge and discharge process is as follows: ； The equalization capacity expression for the presence of an internally short-circuited battery #1 in the battery pack is as follows: ； Therefore, the expression for the leakage capacity of internally short-circuited battery #1 before and after charging and discharging is: ； in, To balance the capacity throughout the entire charging and discharging phase. and These represent the leakage capacity of battery #j during the charging and discharging stages in a battery pack with an internal short circuit under passive equalization. The leakage capacity during the entire charge and discharge phase is set to a negative value; N is the number of batteries connected in series.

5. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 1, is characterized in that... In step S4, under the premise that the battery pack is in a perfectly active balanced state and the SOC remains unchanged before and after charging and discharging, the balanced capacity expressions for the charging and discharging stages of battery #j in the battery pack are derived from the non-short-circuit case as follows: ； ； The equal capacity expression for battery #j before and after the entire charge and discharge process is obtained as follows: ； From the above formula, we can deduce that the battery pack firstly... - Charging, SOC from Increase to Then in time - Discharge, SOC from Reduce to ; and These represent the balanced capacity of battery #j during the charging and discharging phases, respectively, under active balancing. This is to balance the capacity throughout the entire charging and discharging phase.

6. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 5, is characterized in that... In S4, under the premise that the battery pack is in a perfectly active balanced state and the SOC remains unchanged before and after charging and discharging, the equalization capacity expressions for the charging and discharging stages when there is an internal short-circuited battery in the battery pack are further derived from the non-short-circuit case as follows: ； ； The equal capacity expression for battery #j before and after the entire charge and discharge process is obtained as follows: ； The analysis yielded an expression for the balanced capacity of battery #1, which has an internal short circuit in the battery pack, as follows: ； This leads to the expression for the leakage capacity of internally short-circuited battery #1 before and after charging and discharging, which is: ； In the above formula, and These represent the equalization capacity of battery #j in the internal short-circuit battery pack under active equalization during the charging and discharging stages. To balance the capacity throughout the entire charging and discharging phase. and These represent the leakage capacity of battery #j during the charging and discharging stages in the internal short-circuit battery pack under active balancing. This refers to the leakage capacity during the entire charging and discharging phase.

7. The method for quantitatively detecting the internal short-circuit resistance of a battery that is insensitive to aging and load, as described in claim 1, is characterized in that... Ensure that the SOC is the same before discharge and after charging; the equalization capacity is calculated by the equalization current ampere-hour integral method, and the equalization current adopts the classic value recommended by the manufacturer.

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