Method and system for testing stability of lithium battery

Abstract

The invention relates to the technical field of lithium battery stability testing, and discloses a lithium battery stability testing method and system, and the method comprises the steps: obtaining the number of times of cyclic charging and discharging, setting the threshold value of the number of times of cyclic charging and discharging, and carrying out the comparison. According to the method, the cycle charge-discharge times obtained by testing are compared with the cycle charge-discharge time threshold, and if the test result is lower than the cycle charge-discharge time threshold, the service life of the battery is short, and the test is unqualified; if the result reaches or exceeds the cycle charge-discharge frequency threshold value, the durability of the battery meets the requirement, and the test is qualified. The more the cycle charging and discharging times are, the longer the service life of the battery is, and the higher the use quality is.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery stability testing, and in particular to a lithium battery stability testing method and system. Background Art

[0002] Lithium batteries are a type of battery that uses lithium metal or lithium alloys as the negative electrode material and a non-aqueous electrolyte solution. They are divided into two types: lithium metal batteries and lithium-ion batteries. Lithium metal batteries are primary batteries that use manganese dioxide and other materials as the positive electrode. They release electrical energy through the oxidation reaction of metallic lithium. They have high energy density but are non-rechargeable and have high safety requirements. Lithium-ion batteries are rechargeable secondary batteries. The positive electrode uses lithium cobalt oxide, lithium iron phosphate, or a ternary material (such as lithium nickel cobalt manganese oxide), and the negative electrode uses carbon-based materials such as graphite. The charge and discharge cycle is achieved by the insertion and deintercalation of lithium ions between the positive and negative electrodes. Its core structure includes a positive electrode, a negative electrode, a separator, and an electrolyte, and has advantages such as high operating voltage, high energy density, and long cycle life.

[0003] Lithium battery stability testing primarily encompasses thermal stability, electrochemical stability, mechanical stability, and safety. Different testing methods are used to assess lithium battery performance under various usage and extreme conditions. For lithium batteries, beyond safety compliance, effective capacity is the most impactful parameter for users. This is because effective capacity and its decay rate influence the fundamental user experience. From a user's perspective, lithium batteries require not only high effective capacity but also long-lasting performance. Therefore, electrochemical stability testing of lithium batteries is essential. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the object of the present invention is to provide a method and system for testing the stability of lithium batteries, so as to be able to test the effective capacity decay of lithium batteries.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for testing the stability of a lithium battery, comprising: step 1, obtaining the initial effective capacity of the lithium battery, recording the effective capacity of the lithium battery from the initial effective capacity to the initial critical value as the critical effective capacity, and obtaining the number of cycle charge and discharge times of the lithium battery when the effective capacity decreases from the initial effective capacity to the critical effective capacity; step 2, setting a cycle charge and discharge number threshold value of the cycle charge and discharge number when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity according to parameter information and manufacturer's instructions, and the cycle charge and discharge number threshold value is the number of cycle charge and discharge times when the effective capacity decreases from the initial effective capacity to the critical effective capacity. The normal number of charge and discharge cycles; step three, comparing the number of cycle charge and discharge times with the cycle charge and discharge times threshold. If the number of cycle charge and discharge times of the lithium battery is less than the cycle charge and discharge times threshold, it means that when the effective capacity of the lithium battery is reduced from the initial effective capacity to the critical effective capacity, the number of cycle charge and discharge times that can be supported does not reach the normal number. In this case, the lithium battery test fails. If the number of cycle charge and discharge times of the lithium battery is greater than or equal to the cycle charge and discharge times threshold, it means that when the effective capacity of the lithium battery is reduced from the initial effective capacity to the critical effective capacity, the number of cycle charge and discharge times that can be supported can reach or exceed the normal number. In this case, the lithium battery test passes.

[0006] In some embodiments, a second threshold value of the number of charge and discharge cycles is set, and the second threshold value of the number of charge and discharge cycles is less than the threshold value of the number of charge and discharge cycles. When the number of charge and discharge cycles of the lithium battery is less than the threshold value of the number of charge and discharge cycles, the number of charge and discharge cycles is compared with the second threshold value of the number of charge and discharge cycles, and different responses are obtained based on the comparison results.

[0007] In some embodiments, if the number of charge and discharge cycles of the lithium battery is greater than or equal to the second threshold value of the number of charge and discharge cycles, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is lower than the normal number. In this case, the lithium battery is further tested; if the number of charge and discharge cycles of the lithium battery is less than the second threshold value of the number of charge and discharge cycles, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is lower than the normal number. In this case, the lithium battery test remains unqualified.

[0008] In some embodiments, during further testing, the industry average standard effective capacity range is obtained, the standard effective capacity range is compared with the critical effective capacity, and different responses are obtained based on the comparison results.

[0009] In some embodiments, if the critical effective capacity of the lithium battery is greater than the maximum value of the standard effective capacity range, it means that when the effective capacity of the lithium battery is reduced to the critical effective capacity, the remaining effective capacity is greater than the industry standard effective capacity. In this case, the test is passed; if the critical effective capacity of the lithium battery is not greater than the maximum value of the standard effective capacity range, it means that when the effective capacity of the lithium battery is reduced to the critical effective capacity, the remaining effective capacity is not greater than the industry standard effective capacity. In this case, the test fails.

[0010] In some embodiments, when the critical effective capacity of the lithium battery is not greater than the maximum value of the standard effective capacity range and falls within the standard effective capacity range, the initial effective capacity to the critical effective capacity is divided into a first interval and a second interval from large to small, and the number of charge and discharge cycles experienced in the first interval and the second interval is obtained, and the two are compared, and different responses are made according to the comparison results.

[0011] In some embodiments, if the number of charge and discharge cycles experienced in the first interval is greater than or equal to the number of charge and discharge cycles experienced in the second interval, it means that the rate of decrease in the effective capacity of the lithium battery is accelerating. In this case, the lithium battery test fails. If the number of charge and discharge cycles experienced in the first interval is less than the number of charge and discharge cycles experienced in the second interval, the difference between the two is further compared.

[0012] In some embodiments, if the number of charge and discharge cycles experienced in the first interval is less than the number of charge and discharge cycles experienced in the second interval by more than 10%, it means that the effective capacity of the lithium battery is decreasing at a slower rate. In this case, the lithium battery passes the test.

[0013] The present invention also provides the following technical solutions: The present invention further provides a lithium battery stability testing system, which is used to execute the above-mentioned method, including: an acquisition module, which is used to obtain the initial effective capacity of the lithium battery, the effective capacity of the lithium battery reduced from the initial effective capacity to the initial critical value is recorded as the critical effective capacity, and when the effective capacity is reduced from the initial effective capacity to the critical effective capacity, the number of cycle charge and discharge of the lithium battery is obtained; a setting module, which is used to set the cycle charge and discharge number threshold of the cycle charge and discharge number when the effective capacity of the lithium battery is reduced from the initial effective capacity to the critical effective capacity according to parameter information and manufacturer's instructions, and the cycle charge and discharge number threshold is the number of cycle charge and discharge times when the effective capacity is reduced from the initial effective capacity to the critical effective capacity. The normal number of charge and discharge cycles; a comparison module, which is used to compare the charge and discharge cycles with the charge and discharge cycles threshold. If the charge and discharge cycles of the lithium battery are less than the charge and discharge cycles threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that can be supported does not reach the normal number. In this case, the lithium battery test fails; if the charge and discharge cycles of the lithium battery are greater than or equal to the charge and discharge cycles threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that can be supported can reach or exceed the normal number. In this case, the lithium battery test passes.

[0014] The present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the above-mentioned method for testing the stability of a lithium battery.

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: First, the present invention compares the number of charge and discharge cycles obtained from the test with a threshold. If the test result is lower than the threshold, the battery life is insufficient and the test fails. If the result reaches or exceeds the threshold, the battery durability meets the requirements and the test passes. A higher number of charge and discharge cycles indicates a longer battery life and higher quality of use.

[0016] Secondly, in the present invention, a second threshold value of the number of charge and discharge cycles is set, and combined with the comparison between the critical effective capacity of the lithium battery and the standard effective capacity range of the industry, the stability and actual use value of the lithium battery can be evaluated more accurately. When the number of charge and discharge cycles of the lithium battery is slightly lower than the normal number, its durability in actual application can be judged by further evaluation of its critical effective capacity. If the critical effective capacity of the lithium battery is higher than the industry standard, even if the number of charge and discharge cycles is slightly lower, it can still guarantee a longer use time. In this case, the lithium battery can still meet user needs, and the test results can be considered qualified. Compared with simply relying on the number of charge and discharge cycles, this method takes into account the absolute size of the lithium battery capacity, is more in line with actual use scenarios, and avoids overly strict judgment criteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the method steps of the present invention; Figure 2 It is a schematic diagram of the module structure of the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0020] The present invention provides a method for testing the stability of lithium batteries, such as Figure 1 and Figure 2 Shown, including: The first step is to obtain the initial effective capacity of the lithium battery to be tested through the lithium battery parameter information. Set the effective capacity of the lithium battery from the initial effective capacity to the initial critical value, which is recorded as the critical effective capacity. This critical effective capacity is a standard that the effective capacity of the lithium battery has dropped significantly. For example, the effective capacity drops from 100% to 80%, and 80% represents the critical effective capacity. Under this condition, the lithium battery to be tested is cyclically charged and discharged. During the cyclic charge and discharge process, the lithium battery is kept at the same temperature, voltage and current to avoid additional variables affecting the number of cyclic charge and discharge. When the effective capacity of the lithium battery drops from the initial effective capacity to the critical effective capacity, the number of cyclic charge and discharge cycles of the lithium battery is obtained, and this number of cyclic charge and discharge cycles is recorded as a basis for subsequent judgment.

[0021] The second step is to set a charge and discharge cycle threshold for the number of charge and discharge cycles when the effective capacity of the lithium battery drops from the initial effective capacity to the critical effective capacity. This charge and discharge cycle threshold represents the theoretically normal number of charge and discharge cycles when the effective capacity of the lithium battery drops from the initial effective capacity to the critical effective capacity. For lithium batteries, in order to obtain an actual charge and discharge cycle threshold, it is necessary to simulate the charge and discharge behavior of the battery under actual use conditions under test conditions, including repeated charge and discharge cycles at different temperatures, charge and discharge currents, and voltage ranges, and record the capacity attenuation of the battery, so as to obtain the charge and discharge times supported by the lithium battery when a certain capacity attenuation is reached, and thus determine a reasonable charge and discharge cycle threshold.

[0022] The third step is to compare the number of charge and discharge cycles of the lithium battery with the charge and discharge cycle threshold, and different responses are determined based on the comparison results. If the charge and discharge cycle count of the lithium battery is less than the charge and discharge cycle threshold, it means that the number of charge and discharge cycles that the lithium battery can support when the effective capacity decreases from the initial effective capacity to the critical effective capacity does not reach the normal number. In this case, the lithium battery fails the test. If the charge and discharge cycle count of the lithium battery is greater than or equal to the charge and discharge cycle threshold, it means that the number of charge and discharge cycles that the lithium battery can support when the effective capacity decreases from the initial effective capacity to the critical effective capacity reaches or exceeds the normal number. In this case, the lithium battery passes the test. Because the charge and discharge cycle count is equivalent to representing the durability of the lithium battery, the more charge and discharge cycles the lithium battery can support before the effective capacity decreases from the initial effective capacity to the critical effective capacity, the longer the user can use the lithium battery. For example, suppose the standard charge and discharge cycle count for the effective capacity of a lithium battery to decrease from the initial effective capacity to the critical effective capacity is 500. If the charge and discharge cycle count during use reaches 300 times, the effective capacity of the lithium battery has decreased from the initial effective capacity to the critical effective capacity, indicating that the charge and discharge cycle count is lower than normal. For users, this directly impacts the quality of use. If the effective capacity of a lithium battery only decreases from the initial effective capacity to the critical effective capacity after 600 charge-discharge cycles, the cycle count is higher than normal. This indicates that the user experience exceeds expectations and demonstrates high quality. Therefore, in this application, lithium battery stability testing primarily assesses battery durability and capacity decay through cyclic charge-discharge experiments. First, the battery's initial effective capacity is obtained, and a critical effective capacity is set when the capacity drops to a certain percentage (e.g., 80%). The battery is then cyclically charged and discharged under constant temperature, voltage, and current conditions, and the number of cycles at which the effective capacity drops to the critical effective capacity is recorded. Second, through experiments simulating battery usage under different operating conditions, a reasonable cycle threshold is determined, representing the theoretically expected normal cycle life of the battery. Finally, the cycle count obtained from the test is compared with the cycle threshold. If the test result is lower than the cycle threshold, the battery life is insufficient and the test fails. If the result meets or exceeds the cycle threshold, the battery durability meets the requirements and the test passes. The higher the charge and discharge cycle count, the longer the battery life and the higher the quality of use. For example, if the standard charge and discharge cycle threshold is 500 times, but the battery only supports 300 times, it indicates poor durability and affects the user experience. If it can reach 600 times, it indicates that the battery quality is excellent and the service life exceeds expectations.

[0023] When the number of charge and discharge cycles is less than the charge and discharge cycle threshold, a second charge and discharge cycle threshold is set, which is slightly less than the charge and discharge cycle threshold (for example, if the charge and discharge cycle threshold is 500 times, the second charge and discharge cycle threshold is 450 times). On this basis, the charge and discharge cycle of the lithium battery is compared with the second charge and discharge cycle threshold, and different responses are determined based on the comparison results. If the charge and discharge cycle of the lithium battery is greater than or equal to the second charge and discharge cycle threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is lower than the normal number. In this case, the lithium battery is further tested. During further testing, the average standard effective capacity range of lithium batteries in this industry is obtained based on the lithium battery parameter information and the application industry. The standard effective capacity range is compared with the critical effective capacity of the lithium battery, and different responses are made based on the comparison results. If the critical effective capacity of a lithium battery is greater than the maximum value of the standard effective capacity range, it means that the critical capacity of the lithium battery exceeds the industry standard effective capacity. Users will get longer use time from using such a lithium battery than from the industry standard lithium battery. Even if the number of charge and discharge cycles of the lithium battery is lower than the normal number, the impact is not significant because the degree of lower than normal number is low. In addition, the effective capacity is large. Therefore, even if the number of charge and discharge cycles is slightly lower, when the critical effective capacity is reached, the remaining effective capacity is still greater than the industry standard effective capacity. Therefore, the use time is still longer than the industry standard. In this case, the lithium battery passes the battery stability test. If the critical effective capacity of a lithium battery is not greater than the maximum value of the standard effective capacity range, that is, it falls within the standard effective capacity range or is less than the minimum value of the standard effective capacity range, it means that the critical effective capacity of the lithium battery does not exceed the industry standard. In this case, even if the degree of lower than normal number of charge and discharge cycles of the lithium battery is low, the remaining effective capacity is not greater, so the user does not get more use time. Therefore, the lithium battery fails the battery stability test. If the number of charge and discharge cycles of the lithium battery is less than the second threshold value of the number of charge and discharge cycles, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is much lower than the normal number. In this case, the lithium battery test remains unqualified. This method of judging the stability of lithium batteries is mainly based on the fact that the number of charge and discharge cycles of the lithium battery is less than the threshold value of the number of charge and discharge cycles, and then judging the critical effective capacity of the lithium battery within the standard effective capacity range of the industry.Because if the critical effective capacity of a lithium battery is higher than the industry's standard effective capacity range, it means that the lithium battery has a larger effective capacity than conventional lithium batteries in the industry. During normal use, it will have a longer service life than conventional lithium batteries in the industry. Even if the effective capacity drops to the critical effective capacity, the remaining effective capacity is still larger than the standard effective capacity, and the service life is still longer. The longer service life will make up for the fact that the number of charge and discharge cycles is lower than the normal number. For example, assuming that the initial effective capacity of a lithium battery is 10,000 mAh, the industry's standard effective capacity range is 5,000-6,000 mAh, the critical effective capacity is 8,000 mAh, the cycle charge and discharge threshold is 500 times, and the second cycle charge and discharge threshold is 450 times. When the effective capacity of a lithium battery decreases from an initial effective capacity of 10,000 mAh to a critical effective capacity of 8,000 mAh, assuming the number of charge and discharge cycles of the lithium battery is 480, the degree of being lower than the number of charge and discharge cycles is low. However, since the critical effective capacity of 8,000 mAh is greater than the standard effective capacity range of 5,000-6,000 mAh, the lithium battery will still have a longer service life. Therefore, the slightly lower number of charge and discharge cycles can be ignored. This method can more accurately evaluate the stability and actual use value of the lithium battery by setting a second threshold for the number of charge and discharge cycles and combining the critical effective capacity of the lithium battery with the industry's standard effective capacity range. When the number of charge and discharge cycles of a lithium battery is slightly lower than the normal number, its durability in actual application can be judged by further evaluation of its critical effective capacity. If the critical effective capacity of the lithium battery is higher than the industry standard, even if the number of charge and discharge cycles is slightly lower, a longer service life can still be guaranteed. In this case, the lithium battery can still meet user needs and the test results can be considered qualified. Compared to relying solely on the number of charge and discharge cycles, this method takes into account the absolute size of the lithium battery capacity, making it more suitable for actual use scenarios and avoiding overly strict judgment criteria. Through this comprehensive evaluation, not only can the performance of lithium batteries be evaluated even at low charge and discharge cycle times, but it can also more flexibly respond to the needs of different application areas, ensuring that lithium battery stability testing is more scientific and reasonable, helping to improve lithium battery reliability and user experience.

[0024] When the number of charge and discharge cycles of a lithium battery is less than a threshold value for the number of charge and discharge cycles, but greater than or equal to a second threshold value for the number of charge and discharge cycles, and the critical effective capacity of the lithium battery falls within the standard effective capacity range, the interval between the initial effective capacity and the critical effective capacity is divided equally into two intervals: a first interval and a second interval, with the effective capacity of the first interval being greater than that of the second interval. When the effective capacity of the lithium battery decreases to the critical effective capacity, the number of charge and discharge cycles experienced in each interval is obtained, and the number of charge and discharge cycles experienced in the first interval is compared with the number of charge and discharge cycles experienced in the second interval. Different responses are determined based on the comparison results. If the number of charge and discharge cycles experienced in the first interval is greater than or equal to the number of charge and discharge cycles experienced in the second interval, it indicates that the rate of decrease in the effective capacity of the lithium battery is accelerating, and in this case, the lithium battery fails the test. If the number of charge and discharge cycles experienced in the first interval is less than the number of charge and discharge cycles experienced in the second interval, and the degree of less than that is greater than 10%, it indicates that the rate of decrease in the effective capacity of the lithium battery is slowing, and in this case, the lithium battery passes the test. Because in the previous method, when the number of charge and discharge cycles of the lithium battery is slightly lower than the normal number, the critical effective capacity of the lithium battery is taken into account. When the critical effective capacity is greater than the maximum value of the standard effective capacity range, even if the lithium battery has reached the critical effective capacity, the remaining effective capacity is still greater than the standard effective capacity, and it still has a longer service life. Therefore, in this case, the lithium battery is deemed to have passed the test. This method ignores the case where the critical effective capacity is less than or equal to the maximum value of the standard effective capacity range, because in this case, the remaining effective capacity of the lithium battery is not greater than the standard effective capacity. However, when the critical effective capacity is less than the maximum value of the standard effective capacity range, there are two cases, one is that the critical effective capacity falls within the standard effective capacity range; the other is that the critical effective capacity is less than the minimum value of the standard effective capacity range. For the case where the critical effective capacity is less than the minimum value of the standard effective capacity range, the critical effective capacity, that is, not only the remaining effective capacity is less than the standard effective capacity, but also the number of charge and discharge cycles is lower than the normal number, so it is deemed to have failed the test. However, for cases where the critical effective capacity falls within the standard effective capacity range, although the number of charge and discharge cycles is slightly lower than normal, the remaining effective capacity is basically consistent with the standard effective capacity. Therefore, it is not reasonable to directly determine that the test fails. Therefore, an additional judgment is made here, dividing the interval between the critical effective capacity and the initial effective capacity into two, into a first interval and a second interval. For example, the first interval is the effective capacity from 100% to 90%, and the second interval is 90% to 80%.The number of charge and discharge cycles in the two intervals is determined separately, and the difference in the number of charge and discharge cycles in the two intervals is compared. If the number of charge and discharge cycles experienced in the first interval is significantly less than the number of charge and discharge cycles experienced in the second interval, it means that the rate of decrease in the effective capacity of the lithium battery is slowing down, because the effective capacity in the second interval decreases from 90% to 80% and supports more charge and discharge cycles than the effective capacity in the first interval decreases from 100% to 90%. In this case, even if the number of charge and discharge cycles of the lithium battery is slightly lower than the normal number, and the critical effective capacity is basically consistent with the standard effective capacity, the lithium battery test is considered qualified. This method further improves the accuracy and flexibility of the battery stability test by dividing the effective capacity interval of the lithium battery into a first interval and a second interval, and comparing the number of charge and discharge cycles in these two intervals. First, when the number of charge and discharge cycles of the lithium battery is slightly lower than the normal number, but still greater than or equal to the second threshold of the number of charge and discharge cycles, and the critical effective capacity falls within the standard effective capacity range, the interval between the initial effective capacity and the critical effective capacity is divided into two parts. This categorization allows for a more detailed analysis of battery degradation across different capacity ranges, leading to a more scientific assessment of battery performance. If the number of charge-discharge cycles experienced in the first range (higher capacity range) is significantly lower than that in the second range (lower capacity range), with the difference exceeding 10%, this indicates that the rate of effective capacity decline is slowing during capacity decay, indicating that the battery performs relatively steadily in the later stages of degradation. In this case, the battery is considered to have good stability and an acceptable service life, and is therefore considered acceptable. In contrast, if the number of charge-discharge cycles in the first range is higher than that in the second range, this indicates that the battery is degrading more rapidly at low capacity, accelerating the degradation rate and thus affecting its service life. In this case, the battery is considered unqualified. Furthermore, this approach takes into account the relationship between the critical effective capacity and the industry standard effective capacity. When the critical effective capacity falls within the standard effective capacity range, even if the number of charge-discharge cycles is slightly lower than normal, the remaining effective capacity is close to the standard effective capacity, and the user usage time is generally consistent with the industry standard. Therefore, the battery cannot be directly deemed unqualified, thus increasing the rationality and tolerance of the test. Overall, this method makes the test results more in line with actual usage needs through detailed analysis of the battery degradation rate and comprehensive consideration of the changes in effective capacity, improves the scientificity and flexibility of judging the stability of lithium batteries, and avoids unreasonable judgments caused by overly stringent standards.

[0025] In the embodiments disclosed herein, the processes described above with reference to the flowcharts can be implemented as computer software programs. The embodiments disclosed herein include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for executing the method illustrated in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication component and / or installed from removable media. When the computer program is executed by a central processing unit, the functions defined in the methods of this application are performed. It should be noted that the computer-readable medium referred to herein can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or components, or any combination thereof. More specific examples of computer-readable storage media can include, but are not limited to, an electrical connection having one or more wire segments, a portable computer disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. Furthermore, in this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, electrical, optical, RF, or any suitable combination thereof.

[0026] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of the systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or portion of code that contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes can also occur in an order different from that marked in the accompanying drawings. For example, two boxes shown in succession can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, as well as combinations of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified functions or operations, or can be implemented using a combination of dedicated hardware and computer instructions.

[0027] Those skilled in the art should understand that the above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered by the scope of protection of the present application.

Claims

1. A method for testing the stability of a lithium battery, characterized in that: include: Step 1: Obtain the initial effective capacity of the lithium battery. The effective capacity of the lithium battery that decreases from the initial effective capacity to the initial critical value is recorded as the critical effective capacity. When the effective capacity decreases from the initial effective capacity to the critical effective capacity, obtain the number of charge and discharge cycles of the lithium battery. Step 2: Setting a charge and discharge cycle threshold value for the number of charge and discharge cycles when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity according to the parameter information and the manufacturer's instructions. The charge and discharge cycle threshold value is a normal number of charge and discharge cycles when the effective capacity decreases from the initial effective capacity to the critical effective capacity. Step 3: Compare the number of charge and discharge cycles with the charge and discharge cycle threshold. If the number of charge and discharge cycles of the lithium battery is less than the charge and discharge cycle threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that can be supported does not reach the normal number. In this case, the lithium battery test fails. If the number of charge and discharge cycles of the lithium battery is greater than or equal to the charge and discharge cycle threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that can be supported can reach or exceed the normal number. In this case, the lithium battery test has passed.

2. The method for testing the stability of a lithium battery according to claim 1, wherein: A second threshold value of the number of charge and discharge cycles is set. The second threshold value of the number of charge and discharge cycles is less than the threshold value of the number of charge and discharge cycles. When the number of charge and discharge cycles of the lithium battery is less than the threshold value of the number of charge and discharge cycles, the number of charge and discharge cycles is compared with the second threshold value of the number of charge and discharge cycles, and different responses are obtained according to the comparison result.

3. The method for testing the stability of a lithium battery according to claim 2, wherein: If the number of charge and discharge cycles of the lithium battery is greater than or equal to the second threshold value of the number of charge and discharge cycles, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is lower than the normal number. In this case, the lithium battery is further tested. If the number of charge and discharge cycles of the lithium battery is less than the second threshold value of the number of charge and discharge cycles, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that the lithium battery can support is lower than the normal number. In this case, the lithium battery test remains unqualified.

4. The method for testing the stability of a lithium battery according to claim 3, wherein: During further testing, the industry average standard effective capacity range is obtained, and the standard effective capacity range is compared with the critical effective capacity, and different responses are derived based on the comparison results.

5. The method for testing the stability of a lithium battery according to claim 4, wherein: If the critical effective capacity of the lithium battery is greater than the maximum value of the standard effective capacity range, it means that when the effective capacity of the lithium battery is reduced to the critical effective capacity, the remaining effective capacity is greater than the industry standard effective capacity. In this case, the test is passed; if the critical effective capacity of the lithium battery is not greater than the maximum value of the standard effective capacity range, it means that when the effective capacity of the lithium battery is reduced to the critical effective capacity, the remaining effective capacity is not greater than the industry standard effective capacity. In this case, the test fails.

6. The method for testing the stability of a lithium battery according to claim 5, wherein: When the critical effective capacity of the lithium battery is not greater than the maximum value of the standard effective capacity range and falls within the standard effective capacity range, the range from the initial effective capacity to the critical effective capacity is divided into a first interval and a second interval from large to small, the number of charge and discharge cycles experienced in the first interval and the second interval are obtained, and the two are compared, and different responses are made according to the comparison results.

7. The method for testing the stability of a lithium battery according to claim 6, wherein: If the number of charge and discharge cycles experienced in the first interval is greater than or equal to the number of charge and discharge cycles experienced in the second interval, it means that the rate of decrease in the effective capacity of the lithium battery is accelerating. In this case, the lithium battery test fails. If the number of charge and discharge cycles experienced in the first interval is less than the number of charge and discharge cycles experienced in the second interval, the difference between the two is further compared.

8. The method for testing lithium battery stability according to claim 7, wherein: If the number of charge and discharge cycles experienced in the first interval is less than the number of charge and discharge cycles experienced in the second interval by more than 10%, it means that the effective capacity of the lithium battery is decreasing at a slower rate. In this case, the lithium battery test has passed.

9. A lithium battery stability testing system, used to perform the method according to any one of claims 1 to 8, characterized in that: include: An acquisition module is used to obtain the initial effective capacity of the lithium battery. The effective capacity of the lithium battery reduced from the initial effective capacity to the initial critical value is recorded as the critical effective capacity. When the effective capacity is reduced from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles of the lithium battery is obtained; A setting module, which is used to set a cycle charge and discharge number threshold value of the number of cycles when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity according to parameter information and manufacturer instructions. The cycle charge and discharge number threshold value is a normal number of cycles when the effective capacity decreases from the initial effective capacity to the critical effective capacity; A comparison module is used to compare the number of charge and discharge cycles with a threshold value of charge and discharge cycles. If the number of charge and discharge cycles of the lithium battery is less than the threshold value, it means that the effective capacity of the lithium battery has decreased from the initial effective capacity to the critical effective capacity, and the number of charge and discharge cycles that can be supported does not reach the normal number. In this case, the lithium battery test fails. If the number of charge and discharge cycles of the lithium battery is greater than or equal to the charge and discharge cycle threshold, it means that when the effective capacity of the lithium battery decreases from the initial effective capacity to the critical effective capacity, the number of charge and discharge cycles that can be supported can reach or exceed the normal number. In this case, the lithium battery test has passed.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the lithium battery stability testing method according to any one of claims 1 to 8.

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