Lithium battery K value abnormity diagnosis method

Abstract

The invention provides a lithium battery K value abnormity diagnosis method. Comprising the following steps: acquiring an abnormal sample K value, and storing a battery abnormal sample within a first preset temperature range for a first preset duration; measuring the internal resistance value of the abnormal battery sample by using a measuring device to obtain the actual internal resistance value of the abnormal battery sample; comparing the actual internal resistance value of the abnormal battery sample with the calibration theoretical value of the abnormal battery sample; under the condition that the deviation between the inner resistance actual value and the calibration theoretical value is greater than a threshold value, determining that the abnormal type of the abnormal sample of the battery is a physical short circuit; and analyzing the abnormal sample of the battery, searching a short circuit point of the abnormal sample of the battery, and determining a foreign matter source causing the physical short circuit. According to the method, through quick freezing, internal resistance measurement and physical short circuit judgment, the K value abnormal condition of the lithium battery can be quickly and accurately diagnosed, and a physical short circuit source can be quickly positioned. And the production efficiency and the quality control level are improved while the diagnosis efficiency and accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the field of battery fault diagnosis, and in particular to a method for diagnosing abnormal K value of a lithium battery. Background Art

[0002] In lithium-ion battery production, K value refers to the voltage drop of the battery per unit time, usually expressed in mv / h, and is used to measure the self-discharge rate of lithium batteries. In existing manufacturing technology, the K value is usually tested by testing the voltage drop of the battery under certain environmental conditions, within a certain period of time, and with certain equipment. The K value is an indicator of the speed of self-discharge of lithium-ion batteries. However, the main factors affecting the abnormal K value are physical micro-short circuits (physical self-discharge) and chemical self-discharge.

[0003] Under existing manufacturing conditions, after calibrating the battery with abnormal K value, the corresponding problem point is found by disassembly, and then the problem point is analyzed by electron microscope scanning and other methods. The problem point is then checked based on the analyzed substances. As a result, the entire abnormal analysis consumes a lot of time and material resources, which is not conducive to rapid emergency response in the manufacturing process. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for diagnosing abnormal K value of a lithium battery, so as to solve the technical problems in the prior art that the abnormal K value diagnosis process is time-consuming and labor-intensive, and the short-circuit source of the abnormal K value cannot be quickly located, resulting in a large number of poor K values.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for diagnosing abnormal K value of lithium battery is provided. The method comprises: obtaining an abnormal battery sample, the K value of which is within an abnormal range; storing the abnormal battery sample within a first preset temperature range for a first preset time; taking out the abnormal battery sample and using a measuring device to measure the internal resistance value of the abnormal battery sample to obtain the actual value of the internal resistance of the abnormal battery sample; comparing the actual value of the internal resistance of the abnormal battery sample with the calibrated theoretical value of the abnormal battery sample; when the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than a threshold value, determining that the abnormal type of the abnormal battery sample is a physical short circuit; analyzing the abnormal battery sample, finding the short circuit point of the abnormal battery sample, and determining the source of the foreign matter causing the physical short circuit.

[0006] Further, the first preset temperature range is -20°C to -40°C.

[0007] Furthermore, the first preset duration is 6-12 hours.

[0008] Furthermore, obtaining a battery abnormality sample includes: using an OCV device to perform a first open circuit voltage test on multiple test batteries to measure multiple first open circuit voltages, after a first time interval, using the OCV device to perform a second open circuit voltage test on the multiple test batteries to measure multiple second open circuit voltages, calculating K values ​​of the multiple test batteries based on the multiple first open circuit voltages and the corresponding multiple second open circuit voltages, and determining that a test battery among the multiple test batteries whose K value is within the abnormal interval is a battery abnormality sample.

[0009] Further, the K values ​​of multiple test batteries are calculated based on multiple first open circuit voltages and corresponding multiple second open circuit voltages, including: calculating the difference between the first open circuit voltage corresponding to the test battery and the second open circuit voltage corresponding to the test battery; calculating the ratio of the difference to the first time length as the K value of the test battery.

[0010] Furthermore, the abnormal battery sample is taken out and the internal resistance value of the abnormal battery sample is measured using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample, including: within a second time period, allowing the abnormal battery sample to pass a current value of a preset size, and measuring the current voltage value of the abnormal battery sample; and calculating the ratio of the voltage value to the current value as the actual value of the internal resistance of the abnormal battery sample.

[0011] Furthermore, obtaining abnormal battery samples includes: obtaining multiple test batteries whose K values ​​are within the abnormal range; filtering the multiple test batteries to remove the first battery, the second battery, and the third battery from the multiple test batteries, the first battery being a test battery with an abnormal K value due to incomplete battery depolarization, the second battery being a test battery with an abnormal K value due to battery aging, and the first battery being a test battery with an abnormal K value due to test distortion of the test equipment.

[0012] Furthermore, the method includes: when the deviation between the actual value of the internal resistance and the calibrated theoretical value is less than or equal to a threshold value, determining that the abnormal type of the battery abnormal sample is a chemical self-reaction short circuit.

[0013] Furthermore, before comparing the actual value of the internal resistance of the battery abnormal sample with the calibrated theoretical value of the battery abnormal sample, the method includes: obtaining a battery comparison sample; storing the battery comparison sample within a second preset temperature range for a second preset time period; taking out the battery comparison sample and using a measuring device to measure the internal resistance value of the battery comparison sample, and using the measured internal resistance value of the battery comparison sample as the calibrated theoretical value of the battery abnormal sample.

[0014] Furthermore, the second preset temperature range is the same as the first preset temperature range, and the second preset time length is the same as the first preset time length.

[0015] Applying the technical solution of the present invention, first obtain a battery sample with an abnormal K value, place the abnormal battery sample within a first preset temperature range and store it for a certain period of time to ensure that the battery is thoroughly cooled. Then take out the abnormal sample and use a measuring device to accurately measure the internal resistance value of the abnormal battery sample to obtain the actual value of the internal resistance of the abnormal battery sample. Then compare and analyze the actual value of the internal resistance of the abnormal battery sample with the calibrated theoretical value to determine whether there is a deviation. When the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than the set threshold, it is determined that the abnormal type of the abnormal battery sample is a physical short circuit, and the abnormal battery sample is further analyzed to find the short circuit point and determine the source of foreign matter causing the physical short circuit, so as to further eliminate the abnormal situation. The above method can quickly and accurately diagnose the abnormal K value of the lithium battery through rapid freezing, internal resistance measurement and physical short circuit judgment, quickly locate the source of the physical short circuit, and improve production efficiency and quality control level while improving diagnostic efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 A flow chart of an embodiment of a method for diagnosing abnormal K value of a lithium battery according to the present invention is shown. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in a variety of different forms and should not be construed as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of the layers and regions may be enlarged, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

[0022] Combination Figure 1 As shown, according to a specific embodiment of the present application, a method for diagnosing abnormal K value of a lithium battery is provided.

[0023] Specifically, Figure 1 As shown, the method for diagnosing abnormal K value of lithium battery includes: obtaining abnormal battery sample, the K value of the abnormal battery sample is within the abnormal range. The abnormal battery sample is stored in a first preset temperature range for a first preset time, the abnormal battery sample is taken out and the internal resistance value of the abnormal battery sample is measured using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample; the actual value of the internal resistance of the abnormal battery sample is compared with the calibrated theoretical value of the abnormal battery sample. When the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than the threshold value, the abnormal type of the abnormal battery sample is determined to be a physical short circuit, the abnormal battery sample is analyzed, the short circuit point of the abnormal battery sample is found, and the source of the foreign matter causing the physical short circuit is determined.

[0024] In an embodiment of the present application, a battery sample with an abnormal K value is first obtained, and the abnormal battery sample is placed within a first preset temperature range and stored for a certain period of time to ensure that the battery is thoroughly cooled. The abnormal sample is then taken out and the internal resistance value of the abnormal battery sample is accurately measured using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample. The actual value of the internal resistance of the abnormal battery sample is then compared and analyzed with the calibrated theoretical value to determine whether there is a deviation. When the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than the set threshold, the abnormal type of the abnormal battery sample is determined to be a physical short circuit, and the abnormal battery sample is further analyzed to find the short circuit point and determine the source of foreign matter causing the physical short circuit, so as to further eliminate the abnormal situation. The above method can quickly and accurately diagnose the abnormal K value of the lithium battery through rapid freezing, internal resistance measurement and physical short circuit judgment, quickly locate the source of the physical short circuit, and improve production efficiency and quality control level while improving diagnostic efficiency and accuracy.

[0025] Further, the first preset temperature range is -20°C to -40°C.

[0026] Furthermore, the first preset duration is 6-12 hours.

[0027] Furthermore, obtaining a battery abnormality sample includes: using an OCV device to perform a first open circuit voltage test on multiple test batteries to measure multiple first open circuit voltages, after a first time interval, using the OCV device to perform a second open circuit voltage test on the multiple test batteries to measure multiple second open circuit voltages, calculating K values ​​of the multiple test batteries based on the multiple first open circuit voltages and the corresponding multiple second open circuit voltages, and determining that a test battery among the multiple test batteries whose K value is within the abnormal interval is a battery abnormality sample.

[0028] Specifically, first, the first open circuit voltage test is performed on multiple test batteries using an OCV device to measure multiple first open circuit voltage values. Subsequently, after a certain time interval, the OCV device is used again to perform a second open circuit voltage test on these test batteries to obtain multiple second open circuit voltage values. Next, based on these first and second open circuit voltage values, the K value of each test battery is calculated. By analyzing the calculated K value, the test battery located in the abnormal interval is determined to be an abnormal battery sample. This process can effectively screen out battery samples with abnormal K values, ensure that the K value of the battery sample is within the abnormal interval, and provide basic data and information for subsequent diagnosis and troubleshooting.

[0029] Further, the K values ​​of the multiple test batteries are calculated based on the multiple first open circuit voltages and the corresponding multiple second open circuit voltages, including: calculating the difference between the first open circuit voltage corresponding to the test battery and the second open circuit voltage corresponding to the test battery; calculating the ratio of the difference to the first time length as the K value of the test battery. The first preset time length is independent of the first time length and can be selected by the tester.

[0030] Specifically, when calculating the K value of the test battery, it is first necessary to calculate the difference between the first open circuit voltage and the second open circuit voltage corresponding to each test battery. This difference reflects the voltage change of the battery between the two open circuit voltage tests. Subsequently, this difference is calculated by ratio with the time interval between the first open circuit voltage test (i.e., the first duration), and the result is the K value of the test battery. In this way, the K value of each test battery can be accurately calculated, thereby evaluating its self-discharge, which is beneficial to the subsequent diagnosis and treatment of battery abnormalities.

[0031] Furthermore, the abnormal battery sample is taken out and the internal resistance value of the abnormal battery sample is measured using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample, including: within a second time period, allowing the abnormal battery sample to pass a current value of a preset size, and measuring the current voltage value of the abnormal battery sample; and calculating the ratio of the voltage value to the current value as the actual value of the internal resistance of the abnormal battery sample.

[0032] Specifically, when measuring the internal resistance value of an abnormal battery sample, it is first necessary to apply a preset current value to allow the abnormal battery sample to pass through within the second time period, and at the same time measure the current voltage value of the abnormal battery sample. Then, based on the measured voltage and current values, the ratio of the voltage value to the current value is calculated, which is the actual value of the internal resistance of the abnormal battery sample. This process can help accurately measure the internal resistance of the battery and provide important data for evaluating its performance and diagnosing abnormal conditions.

[0033] Furthermore, obtaining abnormal battery samples includes: obtaining multiple test batteries whose K values ​​are within the abnormal range; filtering the multiple test batteries to remove the first battery, the second battery, and the third battery from the multiple test batteries, the first battery being a test battery with an abnormal K value due to incomplete battery depolarization, the second battery being a test battery with an abnormal K value due to battery aging, and the first battery being a test battery with an abnormal K value due to test distortion of the test equipment.

[0034] Specifically, when obtaining abnormal battery samples, it is first necessary to obtain multiple test batteries whose K values ​​are within the abnormal range. Subsequently, these test batteries are filtered to exclude batteries with abnormal K values ​​due to specific reasons. Specifically, it is necessary to remove test batteries with abnormal K values ​​due to incomplete battery depolarization, battery aging, or distortion of the test equipment. This filtering step can effectively screen out battery samples that are truly abnormal, providing an accurate data basis for subsequent problem testing and fault diagnosis.

[0035] Furthermore, the method includes: when the deviation between the actual value of the internal resistance and the calibrated theoretical value is less than or equal to a threshold value, determining that the abnormal type of the battery abnormal sample is a chemical self-reaction short circuit.

[0036] Specifically, when diagnosing abnormal battery samples, if the deviation between the actual value of the internal resistance and the calibrated theoretical value is less than or equal to the set threshold, then it can be determined that the abnormal type of the abnormal battery sample is a chemical self-reaction short circuit. This situation indicates that the internal resistance value of the abnormal battery sample is consistent with or close to the expected value, and the deviation is within the allowable range, so it can be inferred that the abnormality is caused by a chemical self-reaction short circuit. This method can accurately determine the abnormal type of the abnormal battery sample, and this judgment helps to further understand the nature of the battery abnormality.

[0037] Furthermore, before comparing the actual value of the internal resistance of the battery abnormal sample with the calibrated theoretical value of the battery abnormal sample, the method includes: obtaining a battery comparison sample; storing the battery comparison sample within a second preset temperature range for a second preset time period; taking out the battery comparison sample and using a measuring device to measure the internal resistance value of the battery comparison sample, and using the measured internal resistance value of the battery comparison sample as the calibrated theoretical value of the battery abnormal sample.

[0038] Specifically, it is necessary to first obtain a battery comparison sample as a reference, and then compare the actual value of the internal resistance of the abnormal battery sample with the calibrated theoretical value. These comparison samples will be placed in a second preset temperature range and maintained for the same preset time. Subsequently, the battery comparison sample is taken out and its internal resistance value is accurately measured using a measuring device. The internal resistance value of the battery comparison sample obtained by measurement will be used as the calibrated theoretical value of the abnormal battery sample. This step helps to establish a reliable calibration benchmark, which provides accuracy and reliability for the subsequent comparison of the actual value of the internal resistance of the abnormal sample. This comparative analysis method helps to ensure the accuracy and reliability of subsequent processing and diagnosis.

[0039] Furthermore, the second preset temperature range is the same as the first preset temperature range, and the second preset time length is the same as the first preset time length.

[0040] Specifically, when obtaining a battery comparison sample, it is necessary to place it within a second preset temperature range and store it for a certain period of time. The second preset temperature range referred to here is the same as the first preset temperature range. Similarly, the second preset time length is the same as the first preset time length. Such a setting can ensure consistent processing and measurement of battery samples under the same environmental conditions to maintain the comparability and accuracy of the experiment. This consistent processing method can help establish a reliable calibration benchmark and ensure the accuracy of subsequent comparison and analysis of the internal resistance values ​​of abnormal samples.

[0041] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0042] By obtaining a battery sample with an abnormal K value, the abnormal battery sample is placed within a first preset temperature range and stored for a certain period of time to ensure that the battery is thoroughly cooled. Then, the abnormal sample is taken out and the internal resistance value of the abnormal battery sample is accurately measured using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample. Then, the actual value of the internal resistance of the abnormal battery sample is compared and analyzed with the calibrated theoretical value to determine whether there is a deviation. When the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than the set threshold, the abnormal type of the abnormal battery sample is determined to be a physical short circuit, and the abnormal battery sample is further analyzed to find the short circuit point and determine the source of foreign matter causing the physical short circuit, so as to further eliminate the abnormal situation. The above method can quickly and accurately diagnose the abnormal K value of the lithium battery through rapid freezing, internal resistance measurement and physical short circuit judgment, quickly locate the source of the physical short circuit, and improve production efficiency and quality control level while improving diagnostic efficiency and accuracy.

[0043] [Example 1]:

[0044] 1. Calibrate and number the confirmed batteries with poor K values ​​(batteries with poor K values ​​due to poor depolarization effect, inadequate aging temperature and time control, abnormal test equipment, etc. should be excluded here) and record the test data;

[0045] 2. Store the numbered batteries in a -40℃ environment for (6-8) hours (the time here should be verified and given according to the size of the battery, in order to allow the battery to cool thoroughly inside);

[0046] 3. Take out the batteries that have been frozen for a certain period of time and use an OCV device to test the internal resistance of the corresponding number;

[0047] 4. Compare the tested internal resistance with the internal resistance of the battery after freezing with a normal K value, and then confirm whether it is a physical short circuit;

[0048] 5. After confirming the short circuit type, analyze the components of the short circuit object and confirm the source;

[0049] 6. Correct the confirmed source of the problem and close the abnormal K value problem.

[0050] [Example 2]:

[0051] 1. Calibrate and number the confirmed bad K value batteries and record the test data;

[0052] 2. Store the numbered batteries in a -20℃ environment for (10-12) hours (the time can be determined according to the size of the battery, the purpose is to completely freeze the battery);

[0053] 3. Take out the frozen battery, test the ohmic resistance and record the test value according to the corresponding number (force a large current to pass through in a short period of time, generally 40A-80A or even higher, test the voltage across the lithium-ion battery at this time, and calculate the current internal resistance of the battery according to R=U / I);

[0054] 4. Compare the tested internal resistance with the internal resistance of the battery after freezing with a normal K value, and then confirm whether it is a physical short circuit;

[0055] 5. After confirming the short circuit type, analyze the components of the short circuit object and confirm the source;

[0056] 6. Correct the confirmed source of the problem and close the abnormal K value problem.

[0057] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0058] In addition to the above, it should be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of the present invention.

[0059] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for diagnosing abnormal K value of a lithium battery, characterized in that: include: Acquire a battery abnormality sample, wherein the K value of the battery abnormality sample is within the abnormal interval; storing the abnormal battery sample within a first preset temperature range for a first preset time; Taking out the abnormal battery sample and measuring the internal resistance value of the abnormal battery sample using a measuring device to obtain the actual value of the internal resistance of the abnormal battery sample; Comparing the actual value of the internal resistance of the abnormal battery sample with the calibrated theoretical value of the abnormal battery sample; When the deviation between the actual value of the internal resistance and the calibrated theoretical value is greater than a threshold value, determining that the abnormal type of the battery abnormal sample is a physical short circuit; The abnormal battery sample is analyzed to find the short circuit point of the abnormal battery sample and determine the foreign matter source causing the physical short circuit.

2. The method for diagnosing abnormal K value of a lithium battery according to claim 1, characterized in that: The first preset temperature range is -20°C to -40°C.

3. The method for diagnosing abnormal K value of a lithium battery according to claim 1, characterized in that: The first preset duration is 6-12 hours.

4. The method for diagnosing abnormal K value of a lithium battery according to claim 2, characterized in that: Obtain battery abnormality samples, including: Use an OCV device to perform a first open circuit voltage test on multiple test batteries to measure multiple first open circuit voltages. After a first time interval, use the OCV device to perform a second open circuit voltage test on the multiple test batteries to measure multiple second open circuit voltages. Based on the multiple first open circuit voltages and the corresponding multiple second open circuit voltages, calculate the K values ​​of the multiple test batteries, and determine that the test batteries whose K values ​​are within the abnormal range among the multiple test batteries are abnormal battery samples.

5. The method for diagnosing abnormal K value of a lithium battery according to claim 4, characterized in that: Calculating K values ​​of a plurality of the test cells based on a plurality of the first open circuit voltages and a corresponding plurality of the second open circuit voltages comprises: calculating a difference between the first open circuit voltage corresponding to the test cell and the second open circuit voltage corresponding to the test cell; The ratio of the difference to the first time length is calculated as the K value of the test battery.

6. The method for diagnosing abnormal K value of a lithium battery according to claim 1, characterized in that: Taking out the abnormal battery sample and using a measuring device to measure the internal resistance value of the abnormal battery sample to obtain the actual value of the internal resistance of the abnormal battery sample, including: During a second time period, a current value of a preset magnitude is passed through the abnormal battery sample, and a current voltage value of the abnormal battery sample is measured; The ratio of the voltage value to the current value is calculated as the actual value of the internal resistance of the battery abnormality sample.

7. The method for diagnosing abnormal K value of a lithium battery according to claim 1, characterized in that: Obtain battery abnormality samples, including: Obtain multiple test batteries with K values ​​in the abnormal range; The multiple test batteries are filtered to remove the first battery, the second battery, and the third battery among the multiple test batteries, wherein the first battery is a test battery with an abnormal K value due to incomplete battery depolarization, the second battery is a test battery with an abnormal K value due to battery aging, and the first battery is a test battery with an abnormal K value due to test distortion of the test equipment.

8. The method for diagnosing abnormal K value of a lithium battery according to claim 1, characterized in that: The method comprises: when the deviation between the actual value of the internal resistance and the calibrated theoretical value is less than or equal to a threshold value, determining that the abnormal type of the battery abnormal sample is a chemical self-reaction short circuit.

9. The method for diagnosing abnormal K value of a lithium battery according to claim 1 or 7, characterized in that: Before comparing the actual value of the internal resistance of the abnormal battery sample with the calibrated theoretical value of the abnormal battery sample, the method includes: Obtain battery comparison samples; storing the battery comparison sample within a second preset temperature range for a second preset time period; The battery comparison sample is taken out and the internal resistance value of the battery comparison sample is measured using a measuring device, and the measured internal resistance value of the battery comparison sample is used as the calibration theoretical value of the battery abnormal sample.

10. The method for diagnosing abnormal K value of a lithium battery according to claim 9, characterized in that: The second preset temperature range is the same as the first preset temperature range, and the second preset time length is the same as the first preset time length.

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