Lithium battery internal short circuit detection method, device, equipment, medium and program product

Abstract

The invention provides an internal short circuit detection method and device of a lithium battery, equipment, a medium and a program product, and the method comprises the steps: obtaining a characteristic value of a working parameter when the lithium battery is charged and discharged, and determining whether the lithium battery has an internal short circuit or not according to the characteristic value of the working parameter, the characteristic value is used for representing the offset degree of the working parameter at the second moment relative to the working parameter mean value between the first moment and the second moment, so that the lithium battery is detected more effectively through the characteristic value of the working parameter, and the precision and efficiency of internal short circuit detection of the lithium battery are improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, equipment, medium and program product for detecting internal short circuit of a lithium battery. Background Art

[0002] With the continuous development of new energy technology, lithium batteries are widely used in various vehicles and equipment. Since the safety of lithium batteries is an important factor affecting the promotion and use of new energy technologies, lithium battery manufacturers will test whether there is an internal short circuit in lithium batteries after completing the production process of lithium batteries. Only when the lithium batteries they produce do not have abnormalities such as internal short circuits, will they be shipped out of the factory and put into use. Summary of the invention

[0003] The present application provides a method, device, equipment, medium and program product for detecting internal short circuit of lithium batteries, which are used to solve the problems of poor accuracy and low efficiency in the prior art for detecting internal short circuit of lithium batteries.

[0004] In a first aspect, the present application provides a method for detecting an internal short circuit of a lithium battery, comprising: obtaining a characteristic value of an operating parameter of the lithium battery to be detected between a first moment and a second moment when the lithium battery to be detected is charged and discharged, wherein the characteristic value is used to characterize the degree of deviation of the operating parameter at the second moment from the mean value of the operating parameter between the first moment and the second moment;

[0005] Whether the lithium battery has an internal short circuit is determined according to the characteristic value of the operating parameter.

[0006] The second aspect of the present application provides an internal short circuit detection device for a lithium battery, comprising: a memory and a processor; the memory stores computer executable instructions; the processor executes the computer executable instructions stored in the memory, so that the processor executes the method described in the first aspect of the present application.

[0007] A third aspect of the present application provides a computer-readable storage medium storing computer-executable instructions, which, when executed, implement the method described in the first aspect of the present application.

[0008] A fourth aspect of the present application provides a computer program product, including a computer program, which implements the method described in the first aspect of the present application when executed.

[0009] The internal short circuit detection method, device, equipment, medium and program product of a lithium battery provided by the present application obtains the characteristic value of the working parameter of the lithium battery from the first moment to the second moment when the lithium battery is charged and discharged, and determines whether the lithium battery has an internal short circuit based on the characteristic value of the working parameter. Since the characteristic value is used to characterize the degree of deviation of the working parameter at the second moment relative to the mean value of the working parameter in the entire time period from the first moment to the second moment, it can better measure the change of the parameter of the lithium battery during operation. Therefore, when determining whether the lithium battery has an internal short circuit, the present application does not rely on the circuit changes at a certain moment, but rather detects the circuit changes within a time period more comprehensively, thereby more effectively detecting the changes of the lithium battery during the detection process, thereby improving the accuracy and efficiency of internal short circuit detection of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0011] Figure 1 A schematic diagram of the structure of a lithium battery internal short circuit detection device provided in the present application;

[0012] Figure 2 A schematic structural diagram of another lithium battery internal short circuit detection device provided in the present application;

[0013] Figure 3 A schematic diagram of a flow chart of a lithium battery internal short circuit detection method provided in the present application;

[0014] Figure 4 A schematic diagram of the calculation method of the working parameter statistical values ​​provided for this application;

[0015] Figure 5 A schematic diagram of determining the statistical value of a working parameter provided by this application;

[0016] Figure 6 A schematic diagram of a first abnormal threshold value provided in this application;

[0017] Figure 7 A schematic diagram of a second abnormal threshold value provided by the present application;

[0018] Figure 8 A schematic diagram of a flow chart of another embodiment of the internal short circuit detection method of a lithium battery provided in the present application;

[0019] Fig. 9A schematic diagram of a voltage change curve of a lithium battery provided in this application;

[0020] Fig.10 A schematic diagram of a second Z score value change curve of a lithium battery provided in the present application;

[0021] Fig.11 A schematic diagram of a temperature change curve of a lithium battery provided in this application;

[0022] Fig.12 A schematic diagram of a first Z score value change curve of a lithium battery provided in the present application;

[0023] Fig.13 A schematic diagram of a voltage variation curve of another lithium battery provided in this application;

[0024] Fig.14 A schematic diagram of a second Z score value change curve of another lithium battery provided in the present application;

[0025] Fig.15 A schematic diagram of a temperature variation curve of another lithium battery provided in this application;

[0026] Fig.16 A schematic diagram of a first Z score value change curve of another lithium battery provided in the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] The terms "first", "second", "third", "fourth", etc. (if any) 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 data 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 comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] The internal short circuit detection method, device, equipment, storage medium and program product of lithium batteries provided in this application are specifically used in the detection scenario of lithium batteries. Among them, during the production process of lithium batteries, there is a possibility of internal short circuit due to design, incoming materials, technology or process. Once an internal short circuit occurs in a lithium battery, it will cause abnormalities such as high temperature heating, low voltage, increased self-discharge, etc. during the charging and discharging process of the lithium battery, and in severe cases, it may even cause the lithium battery to catch fire or explode.

[0030] Therefore, in one scenario, after the lithium battery manufacturing process is completed, the lithium battery manufacturer will use a special detection device to detect whether the lithium battery has an internal short circuit, providing important leading information for the manufacturer to take appropriate measures for the abnormality of the lithium battery. Only when the lithium battery produced by the manufacturer is found to have no internal short circuit, the manufacturer will ship the lithium battery and put it into use, thereby avoiding the subsequent fire or explosion of the lithium battery, causing more serious safety problems. Alternatively, in another scenario, during the actual use of the lithium battery, the lithium battery can also be detected in real time by the detection device set up to determine whether the lithium battery has an internal short circuit. For example, the manufacturer of an electric vehicle can set up a lithium battery and a detection device corresponding to the lithium battery in the electric vehicle. Once the detection device determines that the lithium battery has an internal short circuit abnormality, it will issue a prompt message or control the lithium battery to stop working, thereby timely avoiding the lithium battery from catching fire or exploding, causing more serious safety problems.

[0031] In the method of detecting internal short circuit of lithium battery provided in the prior art, the detection device generally samples the voltage, current and other circuit parameters of the lithium battery at a specific time. Once the voltage inversion and other conditions of the lithium battery are found, it is determined that the lithium battery has an abnormal internal short circuit. However, the coverage rate of the time of detecting lithium battery in the overall detection process of lithium battery in the prior art is low, and it is impossible to detect the abnormality caused by the internal short circuit of the lithium battery from the overall process. The accuracy and efficiency of the internal short circuit detection of lithium battery are poor. In some cases, if the abnormality of lithium battery cannot be found in the early stage of detection, the lithium battery may even have safety accidents such as smoking in the later stage of detection, which will threaten the safety of detection equipment and operators during the detection stage.

[0032] Based on the problems existing in the prior art, the present application provides a method, device, equipment, medium and program product for detecting internal short circuits of lithium batteries. By detecting the characteristic values ​​of the working parameters between the first moment and the second moment, it is determined whether the lithium battery has an internal short circuit, thereby more comprehensively detecting the changes in the working parameters of the lithium battery over a period of time, and based on the characteristic values, it is able to more accurately determine the internal short circuit anomaly, thereby improving the accuracy and efficiency of internal short circuit detection of lithium batteries. The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0033] Figure 1 A schematic diagram of the structure of a lithium battery internal short circuit detection device provided in this application, such as Figure 1 The internal short circuit detection device 1 shown can be used to connect to a lithium battery and detect whether the lithium battery 2 has an internal short circuit.

[0034] Figure 2 A schematic diagram of the structure of another lithium battery internal short circuit detection device provided in the present application, such as Figure 2 The internal short circuit detection device shown includes a processing unit 101, a control unit 102 and a collection unit 103. This unit division is only a possible implementation method, and the detection device 1 can also be used as a whole, or other unit division methods, which are not limited in this application.

[0035] In one embodiment, the control unit 102 can be used to control the lithium battery 2 to charge and discharge according to a preset detection process. Among them, the preset detection process can be a multi-step and multi-gradient current charge and discharge detection process. When the control unit 102 controls the lithium battery 2 to execute the preset test process, the lithium battery 2 continuously cycles charging and discharging during the test process. The acquisition unit 103 can be used to collect the working parameters of the lithium battery when charging and discharging in the detection process. The working parameters provided in this application include the voltage and temperature of the lithium battery 2. The acquisition unit 103 can collect the working parameters of the lithium battery 2 once at a certain interval from the start time to the end time of the preset detection process, and send the working parameters to the processing unit 101 for processing. The processing unit 101 is used to determine whether the lithium battery 2 has an internal short circuit based on the working parameters of the lithium battery 2 collected by the acquisition unit 103.

[0036] Alternatively, in another embodiment, the control circuit 102 can be used to control the lithium battery 2 to be in a normal working state, so that the lithium battery 2 can supply power to the load, or be charged by a charging device. The lithium battery 2 is continuously charged and discharged during normal operation, and the acquisition unit 103 can be used to collect the working parameters of the lithium battery during charging and discharging in the detection process, and the processing unit 101 determines whether the lithium battery 2 has an internal short circuit based on the working parameters of the lithium battery 2 collected by the acquisition unit 103.

[0037] Combine the following Figure 3 , a specific method for the processing unit 101 to determine whether the lithium battery 2 has an internal short circuit according to the operating parameters of the lithium battery 2 is described. Figure 3 A schematic diagram of a lithium battery internal short circuit detection method provided in this application, such as Figure 3 The method shown can be applied to Figure 1 In the scenario shown, the internal short circuit detection device 1 is used to perform the detection, or it can also be applied to Figure 2 In the scenario shown, the processing unit 101 of the internal short circuit detection device 1 is used to execute the operation. In the subsequent embodiments of the present application, the internal short circuit detection device 1 of the lithium battery is used as the execution subject for explanation, but it is not limited to it. Specifically, Figure 3 The internal short circuit detection method of the lithium battery shown includes:

[0038] S101: The internal short circuit detection device 1 of a lithium battery obtains a characteristic value of an operating parameter of the lithium battery to be detected, wherein the characteristic value is used to characterize the degree of deviation of the operating parameter of the lithium battery 2 at a second moment relative to the mean value of the operating parameter between a first moment and a second moment.

[0039] Among them, the current moment is recorded as the second moment, and the first moment may be the moment before the second moment. When the lithium battery 2 is charged and discharged according to the preset detection process, the first moment may be the starting moment of the detection process. The internal short circuit detection device 1 of the lithium battery can obtain the working parameters at the second moment, and calculate the characteristic values ​​of the working parameters from the first moment to the second moment, or the internal short circuit detection device 1 of the lithium battery can also obtain the characteristic values ​​of the working parameters of the lithium battery 2 at the second moment sent by other devices, and calculate the characteristic values ​​of the working parameters and the calculation of determining whether there is an internal short circuit independently, so as to reduce the amount of calculation required by the detection device 1 and improve the detection speed and efficiency of the internal short circuit.

[0040] In one embodiment, when executing the preset test process, the internal short circuit test is performed on the lithium battery in the tray, that is, the internal short circuit test of the lithium battery 2 described in the present application specifically refers to the test of the cells of multiple lithium batteries placed in the tray. The test process includes multiple storage and gradient charging or discharging steps.

[0041] In one embodiment, the present application provides operating parameters of the lithium battery 2 including the temperature and voltage of the lithium battery 2. The characteristic value of the operating parameter includes a Z-score, wherein the Z-score value can be used to characterize the operating parameter at the second moment, relative to the degree of deviation of the mean of the operating parameter, specifically, the mean can be the mean of the operating parameter from the first moment to the second moment, and the deviation length can be calculated by the standard deviation of the operating parameter.

[0042] Figure 4 A schematic diagram of the calculation method of the characteristic value of the working parameter provided in this application. Among them, the first moment of the preset test process of the lithium battery 2 is t1, the end moment is t2, the duration of the entire cycle is T, and the lithium battery 2 is cyclically charged and discharged between the preset test process t1 and t2. When the current second moment is t0, the internal short circuit detection device 1 obtains the working parameter s at t0, and then substitutes the mean value mean(s) of the working parameter between the first moment t1 and the second moment t0, and the standard deviation std(s) of the working parameter between the first moment t1 and the second moment t0 into the formula Z score calculation formula Z_Score=(s-mean(s)) / std(s), thereby obtaining the Z score value corresponding to the second moment t0.

[0043] More specifically, the Z score value is a standardized measurement method used to indicate the degree of deviation of a value from the average value, especially for data at different times, which can more perfectly reflect the changes in data within the entire time range and better show the overall changes and distribution of data. Therefore, the characteristic value of the working parameter provided in this embodiment is realized by the Z score value, and it can be determined whether the lithium battery has an internal short circuit by detecting the change of the working parameter from the first moment at the beginning of the process to the current second moment. It does not rely on the circuit change at a certain moment, but more comprehensively detects the circuit change during the entire detection process, which can improve the accuracy of detecting the internal short circuit of the lithium battery.

[0044] In one embodiment, the characteristic values ​​of the working parameters acquired by the internal short circuit detection device 1 of the lithium battery in S101 include: the Z score value of the temperature of the lithium battery 2 and the Z score value of the voltage of the lithium battery 2. In the embodiment of the present application, the Z score value of the temperature of the lithium battery 2 is recorded as the first Z score value, and the Z score value of the voltage of the lithium battery 2 is recorded as the second Z score value.

[0045] For example, Figure 5 A schematic diagram of determining characteristic values ​​of working parameters provided in this application, such as Figure 5 The method for calculating the characteristic value of the working parameter by the internal short circuit detection device 1 in S101 is shown. Figure 5As shown, in order to obtain the first Z score value of the temperature and the second Z score value of the voltage in the characteristic value of the working parameter, when the lithium battery 2 is charged and discharged according to the preset detection process, the internal short circuit detection device 1 obtains the real-time temperature st and the real-time voltage sv of the lithium battery 2 at the current second moment. Subsequently, according to the real-time temperature st, the average value mean(st) and the standard deviation std(st) of the temperature of the lithium battery from the first moment t1 of the detection process to the current second moment t0, the first Z score value Zt at the moment t0 is calculated. At the same time, according to the real-time voltage sv, the average value mean(sv) and the standard deviation std(sv) of the voltage of the lithium battery from the first moment t1 of the detection process to the current second moment t0, the second Z score value Zv at the moment t0 is calculated.

[0046] In one embodiment, the internal short circuit detection device 1 performs the above-mentioned Figure 5 The process shown in FIG. 1 is to obtain the working parameters at the current moment and calculate the characteristic values ​​of the working parameters. For example, Figure 4 In the example shown, before the second moment t0, the internal short circuit detection device 1 has acquired 9 working parameters and calculated characteristic values, so the average value and standard deviation corresponding to the current second moment t0 can be calculated by the previous 9 working parameters.

[0047] S102: The internal short circuit detection device 1 of the lithium battery determines whether the lithium battery has an internal short circuit according to the characteristic value of the working parameter obtained in S101.

[0048] In one embodiment, the internal short circuit detection device 1 of the lithium battery compares the first Z score value obtained in S101 with the first abnormal threshold, and compares the second Z score value with the second abnormal threshold, and determines that the lithium battery has an internal short circuit when the first Z score value is greater than the first abnormal threshold and the second Z score value is greater than the second abnormal threshold.

[0049] For example, Figure 6 A schematic diagram of the first abnormal threshold value provided in this application, such as Figure 6 The first abnormal threshold shown is Tr1. When the first Z score value at the second time t0 obtained in S101 is Z11, it is less than the first abnormal threshold Tr1. When the first Z score value at the second time t0 obtained in S101 is Z12, it is greater than the first abnormal threshold Tr1.

[0050] Figure 7 A schematic diagram of the second abnormal threshold value provided in this application, such as Figure 7The second abnormal threshold shown is Tr2. When the second Z score value at the second time t0 obtained in S101 is Z21, it is less than the second abnormal threshold Tr2; when the second Z score value at the second time t0 obtained in S101 is Z22, it is greater than the second abnormal threshold Tr2.

[0051] Combination Figure 6 and Figure 7 When the first Z score value at the second time t0 obtained in S101 is Z12 and the second Z score value is Z22, it is determined that the lithium battery has an internal short circuit.

[0052] In summary, in the internal short circuit detection method provided by the present embodiment, by obtaining the characteristic value of the working parameter from the first moment to the second moment when the lithium battery is charged and discharged, and determining whether the lithium battery has an internal short circuit according to the characteristic value of the working parameter, since the characteristic value is used to characterize the degree of deviation of the working parameter at the second moment relative to the mean value of the working parameter in the entire time period from the first moment to the second moment, the change of the parameter of the lithium battery during operation can be better measured. Therefore, when determining whether the lithium battery has an internal short circuit, the present application does not rely on the circuit change at a certain moment, but more comprehensively detects the circuit change within a time period, thereby more effectively detecting the change of the lithium battery during the detection process, and improving the accuracy and efficiency of the internal short circuit detection of the lithium battery. In addition, the internal short circuit detection method provided by the embodiment of the present application can be applied to various lithium battery systems and models, without the need to perform different tests for each lithium battery, reducing the differentiated calculations caused by different lithium batteries, and the detection process is not limited by the charging and discharging conditions, nor does it need to perform separate tests for each charging and discharging step of the lithium battery, and can be combined with other tests at the same time. The above characteristics make the internal short circuit detection method provided by the present embodiment more conducive to implementation, application and promotion.

[0053] In one embodiment, when the internal short circuit detection device 1 determines that the lithium battery 2 has an internal short circuit abnormality, it also outputs the internal short circuit information of the lithium battery 2. The internal short circuit information includes the abnormal voltage, abnormal temperature, battery barcode, etc. of the lithium battery 2. According to the internal short circuit information, the detection personnel can shield the abnormal lithium battery 2 in time to avoid the lithium battery continuing to charge and discharge and cause safety accidents.

[0054] In one embodiment, the internal short circuit detection device 1 provided in the present application also includes an abnormality processing unit, which is used to shield, isolate, and mark the lithium battery 2 determined to have an internal short circuit abnormality based on the internal short circuit information, thereby reducing the operations required by the detection personnel and improving the intelligence level of the entire detection process.

[0055] Furthermore, the present application also provides a method for determining a first abnormal threshold value Tr1 and a second abnormal threshold value Tr2 by constructing an unsupervised Z score value change curve model. The method can be used by the internal short circuit detection device 1 to determine the first abnormal threshold value Tr1 and the second abnormal threshold value Tr2, or other devices can be used to determine the first abnormal threshold value Tr1 and the second abnormal threshold value Tr2 and send them to the internal short circuit detection device 1. The method is introduced below by taking the internal short circuit detection device 1 determining the first abnormal threshold value Tr1 and the second abnormal threshold value Tr2 as an example.

[0056] For example, Figure 8 A flow chart of another embodiment of the internal short circuit detection method of a lithium battery provided in the present application. In order to calculate the first abnormal threshold value Tr1 and the second abnormal threshold value Tr2, the internal short circuit detection device 1 first needs to provide a plurality of test lithium batteries, and control the plurality of lithium batteries to be charged and discharged according to the same detection process respectively. The duration of the test process is Figure 4 The period T between time t1 and time t2 is shown. The internal short circuit detection device 1 obtains characteristic values ​​of the working parameters of each test battery at multiple test times between time t1 and time t2 when multiple test batteries are charged and discharged according to the detection process. The test time can be Figure 4 Each time interval is a certain amount of time.

[0057] Subsequently, the internal short circuit detection device 1 calculates the first Z score value change curve corresponding to the temperature of the lithium battery 2 and the second Z score value change curve corresponding to the voltage of the lithium battery 2 according to the characteristic values ​​of the working parameters of each test battery in the multiple test batteries. The Z score value change curve can be a continuous curve between time t1 and time t2, thereby covering every moment of the entire detection process.

[0058] Finally, the internal short circuit detection device 1 determines the first abnormal threshold value according to the multiple first Z score value change curves of the multiple tested lithium batteries, and determines the second abnormal threshold value according to the multiple second Z score value change curves of the multiple tested lithium batteries.

[0059] In one embodiment, the plurality of tested lithium batteries may include some lithium batteries without internal short circuits and some lithium batteries with internal short circuits. The internal short circuit detection device 1 marks the Z score value change curves of these tested lithium batteries respectively, and inputs them into an unsupervised machine learning model, and trains through artificial intelligence (AI) to obtain a first abnormal threshold value and a second abnormal threshold value for distinguishing the presence and absence of an internal short circuit.

[0060] For example, the internal short circuit detection device 1 constructs a first model according to the first Z score change curve of multiple tested lithium batteries, thereby determining the first abnormal threshold value through the first model; the internal short circuit detection device 1 also constructs a second model according to the second Z score change curve of multiple tested lithium batteries, thereby determining the second abnormal threshold value through the second model.

[0061] For example, the first model and the second model can both be unsupervised machine learning models.

[0062] Alternatively, in another embodiment, the multiple tested lithium batteries may all be lithium batteries without internal short circuits, and the internal short circuit detection device 1 may obtain a first abnormal threshold value based on the maximum value among the multiple first Z score value change curves of the multiple tested lithium batteries plus a certain first preset value. Since the first Z score values ​​of all tested lithium batteries will not exceed the maximum value, once a first Z score value greater than the first abnormal threshold value is detected, it can be considered that the lithium battery has an internal short circuit. Similarly, the internal short circuit detection device 1 may obtain a second abnormal threshold value based on the maximum value among the multiple second Z score value change curves of the multiple tested lithium batteries plus a certain second preset value.

[0063] The following introduces the Z score value variation curve provided in the embodiment of the present application and the Z score value of the lithium battery with internal short circuit in combination with specific experimental data.

[0064] Figure 9-12 The temperature, voltage and Z score value change curve of the lithium battery without internal short circuit. Fig. 9 As shown, the voltage curves of most of the tested lithium batteries have the same voltage change trend in the entire testing process, only the voltage curve Y1-v of lithium battery Y1 is different from the voltage change of other lithium batteries. Fig. 9 In the voltage variation curve shown in FIG. 1 , the real-time voltage at each test moment is calculated to obtain the first Z score value in the entire detection process as shown in FIG. Fig.10 As shown, the second Z score value Y1-Z2 of the voltage of the lithium battery Y1 exceeds the second abnormal threshold value Tr2, and the second Z score values ​​of other lithium batteries do not exceed the second abnormal threshold value Tr1. Fig.11 As shown in the figure, the temperature curves of all lithium batteries including lithium battery Y1 have the same temperature change trend in the entire detection process. Fig.11 In the temperature change curve shown in the figure, the real-time temperature at each test moment is calculated to obtain the first Z score value in the entire detection process as shown in Fig.12 As shown, the first Z score values ​​of all lithium batteries including lithium battery Y1 do not exceed the first abnormal threshold value Tr1. Therefore, there is no internal short circuit in lithium battery Y1, and the change in voltage curve Y1-v may be caused by other reasons.

[0065] Figure 13-Figure 16 The temperature, voltage and Z score curve of the lithium battery with internal short circuit. Fig.13 As shown, the voltage curves of most of the tested lithium batteries have the same voltage change trend in the entire testing process, only the voltage curve Y2-v of lithium battery Y2 is different from the voltage change of other lithium batteries. Fig.13 In the voltage variation curve shown in FIG. 1 , the real-time voltage at each test moment is calculated to obtain the first Z score value in the entire detection process as shown in FIG. Fig.14 As shown, the second Z score value Y2-Z2 of the voltage of lithium battery Y2 exceeds the second abnormal threshold value Tr2, and the second Z score values ​​of other lithium batteries do not exceed the second abnormal threshold value Tr2. Fig.15 As shown, the temperature curves of most of the tested lithium batteries have the same temperature change trend in the entire testing process, only the temperature curve Y2-t of lithium battery Y2 has a different voltage change from other lithium batteries. Fig.15 In the temperature change curve shown in the figure, the real-time temperature at each test moment is calculated to obtain the first Z score value in the entire detection process as shown in Fig.16 As shown, the first Z score value Y2-Z1 of lithium battery Y2 exceeds the first abnormal threshold value Tr1, and the first Z score values ​​of other lithium batteries do not exceed the first abnormal threshold value Tr1. Therefore, lithium battery Y2 has an internal short circuit, so the temperature of lithium battery Y2 will continue to rise during the charging and discharging process, and the voltage is greater. The Z score value can more clearly show the difference in temperature and voltage between lithium battery Y2 and other lithium batteries without internal short circuits.

[0066] Combination Figure 9-Figure 16 It can be seen that the internal short circuit detection device 1 can calculate the Z score value through the real-time voltage and real-time temperature in the detection process of the lithium battery 2. Since relatively small changes in voltage and temperature correspond to larger changes in the Z score value, the accuracy and effectiveness of the detection are improved. At the same time, it is also possible to detect whether the lithium battery 2 has an internal short circuit more promptly at the moment of abnormality. Therefore, it is not necessary to wait for the lithium battery 2 to complete the entire detection process before determining whether the lithium battery 2 has an internal short circuit. This makes the present embodiment have strong real-time performance and can determine whether the lithium battery 2 has an internal short circuit at the moment when the voltage and temperature are currently collected. This prevents the possibility of safety accidents such as smoke in the later stage of the detection if the internal short circuit abnormality of the lithium battery cannot be found in the early stage of the detection, and further improves the safety of the lithium battery 2 during the detection process.

[0067] In addition, the processing unit 101 provided in the embodiment of the present application may include a hardware structure and / or a software module, and implements the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a function of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0068] For example, the processing unit 101 may be one or more integrated circuits configured to implement the above method or steps, such as one or more application specific integrated circuits (ASIC), or one or more microprocessors (digital signal processors, DSP), or one or more field programmable gate arrays (FPGA), etc. For another example, when the processing unit 101 is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, the processing unit 101 may also be implemented in the form of a system-on-a-chip (SOC).

[0069] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk, (SSD)), etc.

[0070] For example, an embodiment of the present application further provides an internal short circuit detection device for a lithium battery, comprising a processor and a memory; wherein the memory is used to store computer executable instructions, and the processor can execute the computer executable instructions stored in the memory. When the computer executable instructions are executed by the processor, the processor implements any method or any step in the method executed by the processing unit 101 in any of the aforementioned embodiments of the present application.

[0071] The present application also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed, they can be used to implement any method or any step in the method performed by the processing unit 101 in any of the aforementioned embodiments of the present application.

[0072] An embodiment of the present application also provides a chip for executing instructions, wherein the chip is used to execute any method executed by the processing unit 101 as described above in the present application or any step in the method.

[0073] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed, implements any of the methods performed by the processing unit 101 as described above in the present application or any step in the method.

[0074] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting an internal short circuit of a lithium battery, characterized in that: include: Acquire a characteristic value of an operating parameter of the lithium battery to be tested during charging and discharging, wherein the characteristic value is used to characterize a deviation degree of the operating parameter at the second moment relative to a mean value of the operating parameter between the first moment and the second moment; Whether the lithium battery has an internal short circuit is determined according to the characteristic value of the operating parameter.

2. The method according to claim 1, characterized in that The characteristic values ​​of the operating parameters include: a first Z score value of the temperature of the lithium battery and a second Z score value of the voltage of the lithium battery.

3. The method according to claim 2, characterized in that The step of obtaining characteristic values ​​of operating parameters of the lithium battery to be tested during charging and discharging includes: Acquiring the real-time temperature and real-time voltage of the lithium battery at the second moment when the lithium battery is charging or discharging; Obtaining the first Z score value according to the real-time temperature and an average value and a standard deviation of the temperature of the lithium battery between the first moment and the second moment; The second Z score value is obtained according to the real-time voltage and the average value and the standard deviation of the voltage of the lithium battery between the first moment and the second moment.

4. The method according to claim 2, characterized in that: The determining, according to the characteristic value of the operating parameter, whether the lithium battery has an internal short circuit comprises: When the first Z score value is greater than a first abnormal threshold value and the second Z score value is greater than a second abnormal threshold value, it is determined that the lithium battery has an internal short circuit.

5. The method according to claim 4, characterized in that Also includes: Obtain characteristic values ​​of operating parameters of multiple test lithium batteries during charging and discharging; Calculating a first Z-score value change curve of the temperature and a second Z-score change curve of the voltage of the test lithium battery according to the characteristic values ​​of the operating parameters of the multiple test lithium batteries; The first abnormal threshold value is determined according to the first Z score value change curve of the plurality of tested lithium batteries, and the second abnormal threshold value is determined according to the second Z score value change curve of the plurality of tested lithium batteries.

6. The method according to claim 5, characterized in that The determining the first abnormal threshold value according to the first Z score value change curve of the plurality of tested lithium batteries includes: Building a first model according to the first Z score value change curves of the plurality of tested lithium batteries, and determining the first abnormal threshold value through the first model; The determining the second abnormal threshold value according to the second Z score value change curve of the plurality of tested lithium batteries includes: A second model is constructed according to the second Z score value variation curves of the plurality of tested lithium batteries, and the second abnormal threshold value is determined by the second model.

7. The method according to any one of claims 1 to 6, characterized in that: After determining whether the lithium battery has an internal short circuit according to the characteristic value of the operating parameter, the method further includes: When it is determined that the lithium battery has an internal short circuit, the internal short circuit information of the lithium battery is output.

8. A lithium battery internal short circuit detection device, characterized in that: include: Memory and processor; The memory stores computer executable instructions; The processor executes the computer executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: Computer executable instructions are stored, and when the computer executable instructions are executed, the method according to any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The method comprises a computer program, which implements the method according to any one of claims 1 to 7 when being executed.

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