A method for determining the failure location of a lead-acid battery

Abstract

The application provides a method for judging failure position of lead-acid storage battery, and belongs to the technical field of storage battery, and comprises the following steps: after full charging treatment of the lead-acid storage battery to be measured, the upper cover is cut to leak out the pole group; the middle pole is punched to leak out the metal area; the positive electrode surface pen is inserted into the separator fixed by using a voltage measuring instrument, and the negative electrode surface pen is prepared to measure the single cell positive and negative pole; the rated current or power is discharged to the preset terminal voltage, and the negative electrode surface pen is used to measure the pole voltage in sequence during discharging, and the data is recorded according to the fixed frequency; the positive and negative pole voltage drop curves are drawn according to the data, the slopes k1 and k2 are calculated, k1>k2 is that the positive electrode fails first, k1<k2 is that the negative electrode fails first, and k1=k2 is that the electrolyte fails first or the positive and negative electrodes and the electrolyte fail simultaneously. The method for judging failure position of lead-acid storage battery provided by the application significantly shortens the detection period, and solves the problems of long detection period and low efficiency of the existing lead-acid storage battery failure position.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and more specifically, relates to a method for determining the location of failure in a lead-acid battery. Background Technology

[0002] Lead-acid batteries, with their advantages of high output power, long service life, good safety, and inexpensive and readily available raw materials, have been widely used in power systems across various industries, including communications, power, transportation, and energy storage. During battery discharge, abnormal termination of discharge is mainly caused by positive plate failure, negative plate failure, and electrolyte failure. Analyzing and locating the failure site can support the research, development, technological advancement, and production of lead-acid batteries. Currently, there is a lack of efficient methods for detecting battery failure sites, and detection time is typically measured in years, resulting in low efficiency. Therefore, designing a more efficient method for determining the failure location of lead-acid batteries has become an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to provide a method for determining the location of failure in a lead-acid battery, which has a short detection cycle and high detection efficiency.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for determining the location of failure in a lead-acid battery, comprising the following steps: S1. Fully charge the lead-acid battery to be tested, then cut open the top cover of the fully charged battery to expose the electrode group. S2. For 12V lead-acid batteries under test, drill a hole at the middle terminal to expose the metal area of ​​the terminal. For 2V lead-acid batteries under test, there is no need to perform the drilling step; the original metal contact surface of the terminal can be used directly. S3. Using a voltage measuring instrument, insert one end of the positive probe into the partition at any position and fix it, and prepare the negative probe to measure the positive and negative terminals of the unit. S4. Discharge the lead-acid battery under test to the preset termination voltage at the rated current or rated power. During the discharge, insert the negative probe into the positive and negative terminals in sequence to measure the voltage, and record the voltage data of the positive and negative terminals at a fixed frequency. S5: Plot the voltage drop curves of the positive and negative terminals based on the voltage data, calculate the slope k1 of the positive terminal and the slope k2 of the negative terminal, and determine the failure location based on the slope relationship: if k1 > k2, it is determined that the positive terminal fails first; if k1 < k2, it is determined that the negative terminal fails first; if k1 = k2, it is determined that the electrolyte fails first or the positive and negative terminals and the electrolyte fail simultaneously.

[0005] In one possible implementation, in step S1, after the lead-acid battery to be tested is fully charged, it is also necessary to pre-treat the lead-acid battery to be tested, including: wiping the surface of the lead-acid battery casing and top cover with anhydrous ethanol, then placing the lead-acid battery to be tested in an environment with a temperature of 20-25℃ and a humidity of 40%-60% for 30-60 minutes, and then performing the operation of cutting open the top cover.

[0006] In one possible implementation, in step S3, before inserting the positive probe into the separator, the thickness of the separator should be measured in advance, the insertion depth of the positive probe should be controlled to 1 / 2-2 / 3 of the separator thickness, and the insertion position should avoid the edge area of ​​the electrode group. The separator position in the middle of the electrode group should be selected for insertion and fixation.

[0007] In one possible implementation, in step S4, during the discharge and voltage measurement process, temperature monitoring is performed simultaneously, and the recorded voltage data is corrected for temperature compensation based on the monitored temperature data. The temperature compensation correction formula is as follows: ,in This is the voltage temperature coefficient, with a value ranging from 0.003 to 0.005 V / ℃. It is 25℃. This refers to the internal temperature of the battery, which is monitored in real time during the discharge process.

[0008] In one possible implementation, the discharge mode in step S4 can be any one of constant current discharge, constant power discharge, or stepped discharge. The specific steps of the stepped discharge mode are as follows: first, discharge at 80% of the rated current for 1-2 hours, and then discharge at 100% of the rated current to the preset termination voltage. During each stage of discharge, voltage data is recorded at a fixed frequency.

[0009] In one possible implementation, in step S4, when the lead-acid battery under test has a specification of 12V, the preset termination voltage is set to 10.02-10.5V, and when the lead-acid battery under test has a specification of 2V, the preset termination voltage is set to 1.7-1.8V.

[0010] In one possible implementation, in step S5, before plotting the voltage drop curves of the positive and negative terminals, the recorded voltage data is screened using the 3σ criterion to remove outlier data that exceeds the mean ± 3 times the standard deviation of the data. Then, the voltage drop curves are plotted and the slope is calculated based on the screened valid data.

[0011] In one possible implementation, after determining the failure location in step S5, a secondary verification of the failure location is required. The secondary verification includes: conducting specific tests on the determined failed components; if the failure is determined to be a positive / negative electrode failure, measuring the thickness of the positive / negative electrode plates and the shedding rate of the surface active material; if the failure is determined to be an electrolyte failure, detecting the density of the electrolyte, the sulfuric acid concentration, and the impurity content, and confirming the failure location based on the specific test results.

[0012] In one possible implementation, the measurement steps for the shedding rate of the active material on the positive / negative electrode plates are as follows: take a sample of the failed electrode plate and weigh the initial mass of the sample. The sample surface was then rinsed with deionized water, dried, and the remaining mass of the sample was weighed. The shedding rate is η. .

[0013] In one possible implementation, the fixed voltage recording frequency in step S4 is 10-60 s / time, and the casing temperature of the lead-acid battery under test is monitored in real time during the discharge process. When the casing temperature exceeds 45°C, the discharge is paused, and the discharge operation is resumed after the temperature drops below 30°C.

[0014] The beneficial effects of the method for determining the failure location of a lead-acid battery provided by this invention are as follows: Compared with the prior art, the method of this invention only requires the fully charged battery to be left to stand in the environment for 30-60 minutes in the pretreatment stage, without having to wait for the battery to naturally degrade for a long time; the terminal treatment method is designed differently for the two mainstream battery specifications of 12V and 2V, without having to redevelop the detection process for different specifications, thus greatly improving the adaptation efficiency; the discharge and data acquisition stage uses a fixed frequency of 10-60 seconds / time to record data, and provides three fast discharge modes: constant current, constant power, and stepped discharge, avoiding the time-consuming process of "long-term low-current charge and discharge observation" in traditional detection. The core detection process can be completed within a few hours, completely getting rid of the inefficiency of traditional methods measured in "years", significantly shortening the detection cycle and improving detection efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of a method for determining the location of a lead-acid battery failure, provided as an embodiment of the present invention. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0018] Please see Figure 1 The present invention will now describe a method for determining the location of a lead-acid battery failure. The method for determining the location of a lead-acid battery failure includes the following steps: S1. Fully charge the lead-acid battery to be tested, then cut open the top cover of the fully charged battery to expose the electrode group.

[0019] In this step, the battery is first fully charged to ensure it is in a uniform initial state, avoiding any impact from differences in remaining charge on the test results. After full charging, the battery casing and top cover are wiped with anhydrous ethanol. Anhydrous ethanol has excellent cleaning power and is easily volatile, leaving no residue. The battery is then placed in an environment with a temperature of 20-25℃ and humidity of 40%-60% for 30-60 minutes. These environmental parameters are the optimal stable environment for lead-acid batteries, ensuring a uniform and stable internal temperature and complete evaporation of any residual anhydrous ethanol. Only then is the top cover cut open. This step removes impurities from the battery surface, preventing contamination of the electrode groups during testing and reducing measurement interference. Once the internal battery temperature stabilizes, the electrode reactions are in a stable state, ensuring the authenticity and reliability of subsequent voltage measurement data, resulting in more accurate slope calculations and reducing the misjudgment rate of failure locations.

[0020] S2. For 12V lead-acid batteries under test, drill a hole at the middle terminal to expose the metal area of ​​the terminal. For 2V lead-acid batteries under test, there is no need to perform the drilling step; the original metal contact surface of the terminal can be used directly. S3. Using a voltage measuring instrument, insert one end of the positive probe into the partition at any position and fix it. Prepare the negative probe to measure the positive and negative terminals of the cell.

[0021] In this step, the insertion depth and position of the positive electrode probe directly affect the quality of the voltage signal acquisition. If inserted too shallowly, the probe may easily fall out and the voltage near the electrode cannot be accurately acquired; if inserted too deeply, it may puncture the electrode plate, causing secondary damage to the battery; if inserted into the edge area of ​​the electrode group, the voltage data is easily distorted due to uneven current distribution at the edge. Therefore, it is necessary to calibrate the probe insertion before inserting it into the separator. Specifically, this includes: first, measuring the separator thickness, and determining the insertion depth to be 1 / 2-2 / 3 of the separator thickness. This depth range ensures stable probe fixation while accurately acquiring the voltage signal in the center of the electrode group; the insertion position should be chosen in the center of the electrode group, avoiding the edge area, because the current distribution in the center of the electrode group is more uniform, the electrode response is more stable, and the acquired voltage data is more representative.

[0022] S4. Discharge the lead-acid battery under test to the preset termination voltage at the rated current or rated power. During the discharge, insert the negative probe into the positive and negative terminals in sequence to measure the voltage, and record the voltage data of the positive and negative terminals at a fixed frequency.

[0023] In this step, the electrode potential of a lead-acid battery exhibits a significant temperature dependence; temperature changes cause deviations in the voltage measurement. The test results vary greatly under different ambient temperatures, resulting in poor universality. Therefore, a temperature compensation mechanism is needed to eliminate the influence of temperature on voltage measurement. Specifically, the temperature compensation mechanism includes: simultaneously monitoring the temperature during discharge and voltage measurement, and applying temperature compensation correction to the recorded voltage data based on the monitored temperature data. The temperature compensation correction formula is as follows: ,in This is the voltage temperature coefficient, with a value ranging from 0.003 to 0.005 V / ℃. It is 25℃. This refers to the internal temperature of the battery, which is monitored in real time during the discharge process.

[0024] In practical applications, lead-acid batteries exhibit different failure modes depending on the application scenario. For example, batteries in communication base stations are subjected to long-term low-current discharge, while batteries in new energy vehicles are often subjected to high-current discharge. This step provides three selectable modes: constant current discharge, constant power discharge, and stepped discharge. The stepped discharge mode involves first discharging at 80% of the rated current for 1-2 hours, then discharging at 100% of the rated current to a preset termination voltage. Voltage data is recorded at a fixed frequency during each stage of discharge. This mode can simulate the load changes of the battery in actual use and more comprehensively stimulate the battery's failure characteristics.

[0025] In this step, when the lead-acid battery under test has a specification of 12V, the set termination voltage is set to 10.02-10.5V; when the lead-acid battery under test has a specification of 2V, the set termination voltage is set to 1.7-1.8V.

[0026] In this step, the voltage recording frequency is set to 10-60 seconds per recording. This range can be flexibly adjusted according to the battery type; 30 seconds per recording is used for conventional batteries, and 10 seconds per recording is used for batteries operating under special conditions. During the discharge process, the casing temperature is monitored, and a warning threshold of 45°C is set. If the temperature exceeds the threshold, the discharge is paused, and it resumes only when the temperature drops below 30°C. A reasonable recording frequency ensures that key voltage changes are captured while avoiding redundant data and improving data processing efficiency. The temperature protection mechanism effectively prevents safety risks during the discharge process and avoids further damage to the battery from high temperatures, ensuring the safety of the testing process and the accuracy of the test results.

[0027] S5: Plot the voltage drop curves of the positive and negative terminals based on the voltage data, calculate the slope k1 of the positive terminal and the slope k2 of the negative terminal, and determine the failure location based on the slope relationship: if k1 > k2, it is determined that the positive terminal fails first; if k1 < k2, it is determined that the negative terminal fails first; if k1 = k2, it is determined that the electrolyte fails first or the positive and negative terminals and the electrolyte fail simultaneously.

[0028] In this step, abnormal voltage data may be generated during the discharge process due to factors such as instrument fluctuations and external electromagnetic interference. These abnormal data will cause the voltage drop curve to be distorted and the slope calculation result to be incorrect, which will lead to misjudgment of the failure location. Therefore, before plotting the voltage drop curves of the positive and negative terminals, it is necessary to use the 3σ criterion to screen the recorded voltage data, remove abnormal data that exceed the mean ± 3 times the standard deviation of the data, and then plot the voltage drop curve and calculate the slope based on the screened valid data.

[0029] In this step, after the failure location is determined, a secondary verification is required. The secondary verification includes: conducting specific tests on the determined failed component. If the failure is determined to be a positive / negative electrode failure, the thickness of the positive / negative electrode plates and the shedding rate of surface active material are measured. If the failure is determined to be an electrolyte failure, the density of the electrolyte, the sulfuric acid concentration, and the impurity content are tested, and the failure location is confirmed based on the results of the specific tests.

[0030] In application, the measurement steps for the shedding rate of the active material on the positive / negative electrode plates are as follows: take a sample of the failed electrode plate and weigh the initial mass of the sample. The sample surface was then rinsed with deionized water, dried, and the remaining mass of the sample was weighed. The shedding rate is η. .

[0031] This invention provides a method for determining the failure location of a lead-acid battery. Compared with existing technologies, this method, through a clearly defined process including full-charge pretreatment, specification-specific electrode post treatment, standardized discharge, and fixed-frequency data recording, can quickly complete the preliminary determination of the failure location. Combined with subsequent efficient secondary verification, it significantly improves detection efficiency. Moreover, the detection accuracy is extremely high. By controlling the depth and position of the probe insertion into the separator, using a temperature compensation formula to correct voltage data, and applying the 3σ criterion to eliminate abnormal data, the method effectively avoids the influence of external interference, temperature changes, and instrument fluctuations on the detection results. Furthermore, it is designed for different battery specifications. A dedicated termination voltage further reduces the false failure location rate. Subsequent specialized secondary verification of the thickness of the positive and negative plates, the active material shedding rate, and the electrolyte density, sulfuric acid concentration, and impurity content further ensures the accuracy of failure location determination. It also has good applicability and safety, adapting to two common specifications of lead-acid batteries, 12V and 2V, and provides three modes: constant current, constant power, and stepped discharge to meet the battery testing needs in different application scenarios. During the discharge process, the casing temperature is monitored in real time and start-stop thresholds are set, which not only avoids further damage to the battery due to high temperature, but also prevents safety risks.

[0032] Example 1: Failure location detection of a 12V valve-regulated sealed lead-acid battery using a constant power discharge mode.

[0033] Battery parameters: The battery under test is a 12V-390W valve-regulated sealed lead-acid battery with a rated capacity of 100Ah, a preset termination voltage of 10.02V, and an initial voltage of 13.8V when fully charged.

[0034] Implementation steps 1. Full Charge Processing and Pre-treatment: Fully charge the battery under test using a dedicated charger at a charging current of 10A until the voltage stabilizes at 13.8V, then stop charging. Wipe the battery casing and top cover with anhydrous ethanol to remove dust and electrolyte residue, then place the battery in an environment with a temperature of 23℃ and humidity of 50% for 45 minutes.

[0035] 2. Exposing the electrode group and handling the terminal post: Use a special cutting tool to cut open the battery cover to expose the electrode group; drill a hole with a diameter of 5mm at the middle terminal post position to expose the metal area of ​​the terminal post, and clean up the debris around the hole.

[0036] 3. Deployment and calibration of voltage measuring instruments: A digital multimeter with an accuracy of 0.001V is used as the voltage measuring instrument. The thickness of the measuring plate is 2mm. Insert the positive probe into the middle of the plate to a depth of 1mm (1 / 2 of the plate thickness) and fix it firmly. Adjust the negative probe to the normal measuring state.

[0037] 4. Discharge and Data Acquisition: A constant power discharge mode is adopted, with a discharge power of 390W, discharging to the preset termination voltage of 10.02V. During the discharge process, a temperature sensor is used to monitor the internal temperature of the battery simultaneously, recording the positive and negative terminal voltage data every 30 seconds, and recording the real-time temperature. The voltage data is corrected according to the temperature compensation formula. The value is 0.004V / ℃. The average temperature is 26℃. According to the temperature compensation correction formula, we can obtain... = -0.004V. During the discharge process, the casing temperature was monitored. The highest temperature was 38℃, which did not exceed 45℃. The discharge continued until the preset termination voltage was reached, and a total of 280 sets of voltage data were recorded.

[0038] 5. Data Processing and Failure Judgment: The 3σ criterion was used to filter 280 sets of voltage data, removing 3 sets of abnormal data. Based on the remaining 277 sets of valid data, voltage drop curves of the positive and negative terminals were plotted. The slope k1 of the positive terminal was calculated to be -0.012V / min, and the slope k2 of the negative terminal was -0.005V / min. Since the absolute value of k1 is greater than the absolute value of k2, i.e., k1 > k2, it was initially determined that the positive terminal of the battery failed first.

[0039] 6. Secondary Failure Verification: Take a sample of the positive electrode plate of the battery and weigh its initial mass. =50.2g, rinsed with deionized water and dried, weigh the remaining mass. =42.3g, the active material shedding rate η = (50.2-42.3) / 50.2×100%≈15.7%, which far exceeds the normal shedding rate threshold of 5%; the average thickness of the positive electrode plate was measured to be 2.1mm, which is lower than the standard thickness of 3.0mm, confirming that the positive electrode plate is in failure.

[0040] Example 2: Failure location detection of a 2V lead-acid battery using a stepped discharge mode.

[0041] Battery parameters: The battery under test is a 2V-200Ah lead-acid battery with a rated power of 400W, a preset termination voltage of 1.8V, and an initial voltage of 2.1V when fully charged.

[0042] Implementation steps 1. Full charge treatment and pretreatment: After fully charging the battery, wipe the outer shell with anhydrous ethanol, place it in an environment of 22℃ and 45% humidity for 30 minutes, and prepare for testing after the surface is dry.

[0043] 2. Electrode exposure and terminal treatment: Cut open the battery cover to expose the electrode group. This battery is a 2V battery and does not require drilling.

[0044] 3. Deployment and calibration of voltage measuring instruments: A voltage measuring instrument is used, with a separator thickness of 2.5mm and a positive probe insertion depth of 1.5mm (3 / 5 of the separator thickness), fixed at the middle separator position of the electrode group.

[0045] 4. Discharge and Data Acquisition: A stepped discharge mode was adopted, first discharging at 80% of the rated current (64A) for 1.5 hours, then discharging at the rated current (80A) until the termination voltage of 1.8V. The voltage recording frequency was 20 seconds / time, with simultaneous monitoring of the internal temperature, which averaged 24℃, requiring no temperature compensation. The highest temperature of the casing during the discharge process was 40℃, without triggering the pause mechanism. A total of 320 sets of voltage data were recorded.

[0046] 5. Data processing and failure judgment: After screening by the 3σ criterion, two sets of abnormal data were removed. The voltage drop curve was plotted, and the slope of the positive electrode k1 was calculated to be -0.006V / min, and the slope of the negative electrode k2 was -0.006V / min. Since k1=k2, it was initially judged that the electrolyte failed first.

[0047] 6. Secondary Failure Verification: Electrolyte samples were taken from inside the battery, and the electrolyte density was found to be 1.15 g / cm³. 3 The density is 1.28 g / cm³ lower than the standard. 3 The sulfuric acid concentration was 15%, which is lower than the standard concentration of 37%; the impurity content was 0.8%, which is higher than the standard threshold of 0.3%, confirming that the electrolyte was ineffective.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining the location of failure in a lead-acid battery, characterized in that, Includes the following steps: S1. Fully charge the lead-acid battery to be tested, then cut open the top cover of the fully charged battery to expose the electrode group. S2. For 12V lead-acid batteries under test, drill a hole at the middle terminal to expose the metal area of ​​the terminal. For 2V lead-acid batteries under test, there is no need to perform the drilling step; the original metal contact surface of the terminal can be used directly. S3. Using a voltage measuring instrument, insert one end of the positive probe into the partition at any position and fix it, and prepare the negative probe to measure the positive and negative terminals of the unit. S4. Discharge the lead-acid battery under test to the preset termination voltage at the rated current or rated power. During the discharge, insert the negative probe into the positive and negative terminals in sequence to measure the voltage, and record the voltage data of the positive and negative terminals at a fixed frequency. S5: Plot the voltage drop curves of the positive and negative terminals based on the voltage data, calculate the slope k1 of the positive terminal and the slope k2 of the negative terminal, and determine the failure location based on the slope relationship: if k1 > k2, it is determined that the positive terminal fails first; if k1 < k2, it is determined that the negative terminal fails first; if k1 = k2, it is determined that the electrolyte fails first or the positive and negative terminals and the electrolyte fail simultaneously.

2. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S1, after the lead-acid battery to be tested is fully charged, it is also necessary to pre-treat the lead-acid battery to be tested, including wiping the surface of the lead-acid battery casing and top cover with anhydrous ethanol, then placing the lead-acid battery to be tested in an environment with a temperature of 20-25℃ and a humidity of 40%-60% for 30-60 minutes, and then performing the operation of cutting open the top cover.

3. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S3, before inserting the positive electrode probe into the separator, the thickness of the separator should be measured in advance. The insertion depth of the positive electrode probe should be controlled to 1 / 2 to 2 / 3 of the separator thickness, and the insertion position should avoid the edge area of ​​the electrode group. The separator position in the middle of the electrode group should be selected for insertion and fixation.

4. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S4, during the discharge and voltage measurement process, temperature monitoring is performed simultaneously. The recorded voltage data is then corrected for temperature compensation based on the monitored temperature data. The temperature compensation correction formula is as follows: ,in This is the voltage temperature coefficient, with a value ranging from 0.003 to 0.005 V / ℃. It is 25℃. This refers to the internal temperature of the battery, which is monitored in real time during the discharge process.

5. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, The discharge mode in step S4 can be any one of constant current discharge, constant power discharge, or stepped discharge. The specific steps of the stepped discharge mode are as follows: first, discharge at 80% of the rated current for 1-2 hours, and then discharge at 100% of the rated current to the preset termination voltage. During each stage of discharge, the voltage data is recorded at a fixed frequency.

6. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S4, when the lead-acid battery under test has a specification of 12V, the preset termination voltage is set to 10.02-10.5V, and when the lead-acid battery under test has a specification of 2V, the preset termination voltage is set to 1.7-1.8V.

7. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S5, before plotting the voltage drop curves of the positive and negative terminals, the recorded voltage data is screened using the 3σ criterion to remove outlier data that exceeds the mean ± 3 times the standard deviation. Then, the voltage drop curves are plotted and the slope is calculated based on the screened valid data.

8. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, After determining the failure location in step S5, a secondary verification of the failure location is required. The secondary verification includes: conducting specific tests on the determined failed components. If the failure is determined to be a positive / negative electrode failure, the thickness of the positive / negative electrode plates and the shedding rate of surface active materials are measured. If the failure is determined to be an electrolyte failure, the density of the electrolyte, the sulfuric acid concentration, and the impurity content are tested, and the failure location is confirmed based on the results of the specific tests.

9. The method for determining the location of failure in a lead-acid battery as described in claim 8, characterized in that, The measurement steps for the shedding rate of the active material on the positive / negative electrode plates are as follows: take a sample of the failed electrode plate and weigh the initial mass of the sample. The sample surface was then rinsed with deionized water, dried, and the remaining mass of the sample was weighed. The shedding rate is η. .

10. The method for determining the location of failure in a lead-acid battery as described in claim 1, characterized in that, In step S4, the fixed voltage recording frequency is 10-60 seconds / time, and the casing temperature of the lead-acid battery under test is monitored in real time during the discharge process. When the casing temperature exceeds 45°C, the discharge is paused and the discharge operation is resumed after the temperature drops below 30°C.

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