Battery module expansion detection method and device, electronic equipment and storage medium

Abstract

The embodiment of the invention discloses a battery module expansion detection method and device, electronic equipment and a storage medium. The expansion detection method of the battery module comprises the following steps: acquiring the vibration frequency of a hooping piece used for hooping each single battery in the battery module; according to the vibration frequency of the hooping piece, the tensile force borne by the hooping piece is determined; and obtaining the internal expansion force of the battery module according to the drawing force borne by the hooping piece. According to the expansion detection method of the battery module provided by the embodiment of the invention, the accuracy of expansion detection of the battery module can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, electronic device and storage medium for detecting expansion of a battery module. Background Art

[0002] The expansion force of the battery cells inside the battery module will affect the performance of the battery module, so it is necessary to perform expansion testing on the battery module to detect its internal expansion force.

[0003] In the related art, the expansion detection method for the battery module is to implant a pressure sensor in the battery module to detect the internal expansion force of the battery module through the pressure sensor. However, this method requires the battery module to be disassembled and the pressure sensor to be implanted in order to determine the internal expansion force of the battery module. In the process of disassembling the battery module, the battery module will undergo plastic deformation due to the disassembly. After the pressure sensor is implanted, the battery module cannot be restored to the state before disassembly, resulting in the expansion force obtained by the pressure sensor being too different from the actual expansion force of the battery module, affecting the accuracy of the expansion detection of the battery module. Summary of the invention

[0004] In view of the above problems, the present application provides a method, device, electronic device and storage medium for detecting expansion of a battery module, which can improve the accuracy of expansion detection of the battery module.

[0005] In a first aspect, an embodiment of the present application provides a method for detecting expansion of a battery module, the method comprising: obtaining a vibration frequency of a clamping member used to clamp each battery cell in the battery module; determining a tensile force applied to the clamping member based on the vibration frequency of the clamping member; and obtaining an internal expansion force of the battery module based on the tensile force applied to the clamping member.

[0006] In the technical solution of the embodiment of the present application, the vibration frequency of the clamp used to clamp each battery cell in the battery module is obtained, and the tensile force on the clamp is determined according to the vibration frequency of the clamp, so as to obtain the internal expansion force of the battery module according to the tensile force on the clamp. Since the vibration frequency of the material is related to the stiffness coefficient of the material itself, when the expansion force is generated inside the battery module, the clamp will be squeezed and stretched, changing its stiffness coefficient, causing its vibration frequency to change. Therefore, the tensile force on the clamp due to battery expansion can be marked by the vibration frequency of the clamp, so as to use the tensile force to determine the internal expansion force of the battery module without disassembling the battery module, thereby improving the accuracy of expansion detection of the battery module.

[0007] In some embodiments, obtaining the vibration frequency of a clamping member used to clamp each battery cell in a battery module includes: obtaining the regional vibration frequencies of multiple regions on the outer surface of the clamping member; and determining the vibration frequency of the clamping member according to the regional vibration frequencies. This makes the obtained vibration frequency of the clamping member more consistent with the actual situation, improves the accuracy of the internal expansion force subsequently determined by the vibration frequency, and further improves the accuracy of the expansion detection of the battery module.

[0008] In some embodiments, the vibration frequency of the clamp is determined according to the vibration frequency of each region, including: determining the vibration frequency of the clamp according to the frequency peak of each region. Since the tensile force corresponding to the frequency peak in the vibration frequency of each component is most affected by the internal expansion force of the battery module compared with the tensile force corresponding to the vibration frequency of other regions, and can better reflect the actual situation of the internal expansion force, the frequency peak is determined as the vibration frequency of the clamp, so that the obtained vibration frequency of the clamp can more accurately reflect the influence of the internal swelling force on the vibration frequency of the clamp, so that the obtained vibration frequency of the clamp is more in line with the actual situation, and the accuracy of the internal expansion force determined by the vibration frequency is improved, thereby further improving the accuracy of the expansion detection of the battery module.

[0009] In some embodiments, the tensile force exerted on the hoop is determined according to the vibration frequency of the hoop, including: inputting the vibration frequency of the hoop into a fitting model representing the corresponding relationship between the vibration frequency and the tensile force, and determining the tensile force exerted on the hoop; wherein the fitting model is determined by the vibration frequency corresponding to the hoop under different tensile forces, so that when it is necessary to determine the tensile force exerted on the hoop, it is not necessary to determine it by searching for data, thereby reducing the situation where the tensile force corresponding to the vibration frequency of the hoop cannot be obtained by searching for data, and improving the efficiency of obtaining the tensile force. Moreover, by determining the tensile force exerted on the hoop by fitting the model, the determined tensile force can be made more accurate, and the accuracy of subsequent expansion detection of the battery module using the tensile force can be improved.

[0010] In some embodiments, the internal expansion force of the battery module is obtained according to the tensile force on the clamp, including: obtaining the internal expansion force of the battery module according to the preset expansion force corresponding to the target tensile force matching the tensile force among the preset tensile forces; wherein the preset tensile force corresponding to any of the preset expansion forces is determined according to the tensile force of the clamp when the internal expansion force of the battery module is the preset expansion force. Thus, the internal expansion force of the battery module obtained can be more consistent with the actual situation, thereby improving the accuracy of the internal expansion force obtained.

[0011] In some embodiments, the internal expansion force of the battery module is obtained according to the tensile force exerted on the clamp, including: inputting the tensile force into a preset model representing the corresponding relationship between the tensile force and the internal expansion force to obtain the internal expansion force of the battery module; wherein the preset model is determined by the tensile force corresponding to the clamp under different internal expansion forces of the battery module. Therefore, when it is necessary to determine the internal expansion force of the battery module, it is not necessary to determine it by searching for data, thereby reducing the situation where the internal expansion force corresponding to the tensile force cannot be obtained by searching for data, and improving the efficiency of obtaining the internal expansion force. Moreover, determining the internal expansion force of the battery module by using a preset model can make the determined internal expansion force more accurate, thereby improving the accuracy of expansion detection of the battery module.

[0012] In some embodiments, the method further includes: determining that the battery module has abnormal expansion according to the internal expansion force of the battery module, obtaining the component vibration frequency of the components in the battery module; and determining the expansion detection result of the components according to the component vibration frequency. Thus, when the battery module has abnormal expansion, the reliability of the components in the battery module can be effectively evaluated.

[0013] In some embodiments, determining the expansion detection result of the component according to the component vibration frequency of the component includes: comparing the component vibration frequency of the component with the initial vibration frequency of the component to obtain the expansion detection result of the component. Thus, the reliability of the component can be quickly evaluated, and the evaluation efficiency of the reliability of the component is improved.

[0014] In a second aspect, the present application provides an expansion detection device for a battery module, comprising: a frequency acquisition module for acquiring the vibration frequency of a clamping member in the battery module for clamping each battery cell; a stretching detection module for determining the stretching force applied to the clamping member based on the vibration frequency of the clamping member; and an expansion detection module for obtaining the internal expansion force of the battery module based on the stretching force applied to the clamping member.

[0015] In the technical solution of the embodiment of the present application, the vibration frequency of the clamp used to clamp each battery cell in the battery module is obtained, and the tensile force on the clamp is determined according to the vibration frequency of the clamp, so as to obtain the internal expansion force of the battery module according to the tensile force on the clamp. Since the vibration frequency of the material is related to the stiffness coefficient of the material itself, when the expansion force is generated inside the battery module, the clamp will be squeezed and stretched, changing its stiffness coefficient, causing its vibration frequency to change. Therefore, the tensile force on the clamp due to battery expansion can be marked by the vibration frequency of the clamp, so as to use the tensile force to determine the internal expansion force of the battery module without disassembling the battery module, thereby improving the accuracy of expansion detection of the battery module.

[0016] In some embodiments, the frequency acquisition module is specifically used to: acquire regional vibration frequencies of multiple regions on the outer surface of the clamp; and determine the vibration frequency of the clamp according to the vibration frequencies of each region.

[0017] In some embodiments, the frequency acquisition module is specifically used to determine the vibration frequency of the tightening member according to the frequency peak value of the vibration frequency of each of the regions.

[0018] In some embodiments, the stretching detection module is specifically used to: input the vibration frequency of the fastening member into a fitting model representing the corresponding relationship between the vibration frequency and the stretching force, and determine the stretching force exerted on the fastening member; wherein the fitting model is determined by the vibration frequency corresponding to the fastening member under different stretching forces.

[0019] In some embodiments, the expansion detection module is specifically used to: obtain the internal expansion force of the battery module according to the preset expansion force corresponding to the target stretching force matching the stretching force among the preset stretching forces; wherein the preset stretching force corresponding to any of the preset expansion forces is determined according to the stretching force of the tightening member when the internal expansion force of the battery module is the preset expansion force.

[0020] In some embodiments, the expansion detection module is specifically used to: input the tensile force into a preset model representing the correspondence between the tensile force and the internal expansion force to obtain the internal expansion force of the battery module; wherein the preset model is determined by the tensile force corresponding to the tightening member under different internal expansion forces of the battery module.

[0021] In some embodiments, the expansion detection module is also used to: determine whether the battery module has abnormal expansion based on the internal expansion force of the battery module, and obtain the component vibration frequency of the components in the battery module; and determine the expansion detection result of the component based on the component vibration frequency of the component.

[0022] In some embodiments, the expansion detection module is specifically used to compare the component vibration frequency of the component with the initial vibration frequency of the component to obtain the expansion detection result of the component.

[0023] In a third aspect, the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the method in the implementation of the first aspect when executing the computer program.

[0024] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the method in the implementation of the first aspect.

[0025] In a fifth aspect, the present application provides a computer program product, which, when running on a computer, enables the computer to execute the method in the first aspect or any optional implementation manner of the first aspect.

[0026] In a sixth aspect, the present application provides a battery management system having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the method in the implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings: Figure 1 A first flow chart of a method for detecting expansion of a battery module according to some embodiments of the present application; Figure 2 A schematic diagram of a battery module according to some embodiments of the present application; Figure 3 A schematic diagram of the corresponding relationship between the vibration frequency and the stretching force in some embodiments of the present application; Figure 4 A second flow chart of a method for detecting expansion of a battery module according to some embodiments of the present application; Figure 5 This is a schematic structural diagram of a battery module expansion detection device according to some embodiments of the present application; Figure 6 This is a schematic diagram of the structure of an electronic device according to some embodiments of the present application.

[0028] The reference numerals in the specific implementation manner are as follows: 301 - frequency acquisition module; 302 - stretching detection module; 303 - expansion detection module; 4 - electronic device; 401 - processor; 402 - memory; 403 - communication bus. DETAILED DESCRIPTION

[0029] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0031] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0032] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0034] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0035] A battery module is a combination of multiple battery cells connected in series, parallel or series-parallel. The expansion force of the battery cells inside the battery module will affect the performance of the battery module. Therefore, it is necessary to perform expansion testing on the battery module to detect its internal expansion force.

[0036] In the related art, the expansion detection method for the battery module is to implant a pressure sensor in the battery module to detect the internal expansion force of the battery module through the pressure sensor. However, this method requires the battery module to be disassembled and the pressure sensor to be implanted in order to determine the internal expansion force of the battery module. In the process of disassembling the battery module, the battery module will undergo plastic deformation due to the disassembly. After the pressure sensor is implanted, the battery module cannot be restored to the state before disassembly, resulting in the expansion force obtained by the pressure sensor being too different from the actual expansion force of the battery module, affecting the accuracy of the expansion detection of the battery module.

[0037] In response to the above technical problems, the embodiment of the present application obtains the vibration frequency of the clamping member used to clamp each battery cell in the battery module, and determines the tensile force on the clamping member according to the vibration frequency of the clamping member, so as to obtain the internal expansion force of the battery module according to the tensile force on the clamping member. Since the vibration frequency of the material is related to the stiffness coefficient of the material itself, when the expansion force is generated inside the battery module, the clamping member will be squeezed and stretched, changing its stiffness coefficient and causing its vibration frequency to change. Therefore, the tensile force on the clamping member due to battery expansion can be marked by the vibration frequency of the clamping member, so as to use the tensile force to determine the internal expansion force of the battery module without disassembling the battery module, thereby improving the accuracy of the expansion detection of the battery module.

[0038] The expansion detection method, device, electronic device and storage medium of the battery module disclosed in the embodiments of the present application can be applied to electronic devices for expansion detection of battery modules. Among them, the terminal device can be a mobile terminal, a desktop terminal, a vehicle-mounted terminal, a battery management system or a server. The server can be an independent server or a server cluster composed of multiple servers, and can also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence sampling point devices.

[0039] According to some embodiments of the present application, a battery module expansion detection method is provided, and the battery module expansion detection method can be applied to the aforementioned electronic device. Figure 1 As shown, the expansion detection method of the battery module includes: S101, obtaining a vibration frequency of a clamping member used to clamp each battery cell in a battery module; S102, determining the tensile force exerted on the tightening member according to the vibration frequency of the tightening member; S103, obtaining the internal expansion force of the battery module according to the tensile force applied to the clamp.

[0040] The battery module includes a plurality of battery cells and a clamp, and each battery cell is connected in series, in parallel, or in series and in parallel. The clamp is used to fix and support the battery module so that each battery cell in the battery module fits tightly. Figure 2 As shown. Exemplarily, the clamping member may be a strapping belt or a clamp, such as a steel strap clamp or a clamp made of other materials, to clamp each battery cell in the battery module to stabilize the position of the battery cell in the battery module.

[0041] When expansion detection of the battery module is required, the vibration frequency of the clamping member can be collected by a sensor, such as a vibration sensor, disposed on the outer surface of the clamping member, so as to obtain the vibration frequency of the clamping member through the sensor. For example, the vibration frequency of the middle position of the outer surface of the clamping member can be collected by the sensor, so as to determine the vibration frequency as the vibration frequency of the clamping member.

[0042] The vibration frequency f of the material is related to the material's own mass m and stiffness coefficient k, that is, , when the mass of the material itself remains unchanged, there is a fixed relationship between the vibration frequency and the stiffness coefficient k of the material. When the expansion force is generated inside the battery module, the clamp will be squeezed and stretched, causing plastic deformation, which will cause the stiffness coefficient of the clamp to change. Since there is a fixed relationship between the vibration frequency and the stiffness coefficient k of the material when the mass of the material itself remains unchanged, the tensile force on the clamp caused by the internal expansion force of the battery module can be reflected in the vibration frequency of the clamp.

[0043] Based on this, different tensile forces, such as 0-28000N tensile force, can be used in advance to test the tension of the same clamping member samples as the clamping member, and the vibration frequencies corresponding to the clamping member samples under different tensile forces can be detected to obtain a mapping table recording the corresponding relationship between each tensile force and each vibration frequency. After obtaining the vibration frequency of the clamping member in the battery module, the tensile force corresponding to the vibration frequency in the mapping table can be determined as the tensile force on the clamping member.

[0044] After determining the tensile force on the clamp, the internal expansion force of the battery module can be obtained according to the tensile force on the clamp. For example, the tensile force on the clamp can be determined as the internal expansion force of the battery module.

[0045] By obtaining the vibration frequency of the clamp used to clamp each battery cell in the battery module, and determining the tensile force on the clamp according to the vibration frequency of the clamp, the internal expansion force of the battery module is obtained according to the tensile force on the clamp. Since the vibration frequency of the material is related to the stiffness coefficient of the material itself, when the expansion force is generated inside the battery module, the clamp will be squeezed and stretched, changing its stiffness coefficient, causing its vibration frequency to change. Therefore, the tensile force on the clamp due to battery expansion can be marked by the vibration frequency of the clamp, so as to use the tensile force to determine the internal expansion force of the battery module without disassembling the battery module, thereby improving the accuracy of battery module expansion detection.

[0046] In order to further improve the accuracy of expansion detection of the battery module, in some embodiments, the vibration frequency of the clamping member used to clamp each battery cell in the battery module is obtained, including: obtaining the regional vibration frequencies of multiple areas on the outer surface of the clamping member; and determining the vibration frequency of the clamping member based on the vibration frequencies of each area.

[0047] In some embodiments, when it is necessary to determine the vibration frequency of the hoop, the vibration frequency of each area can be collected by sensors disposed in different areas of the outer surface of the hoop, so as to obtain the vibration frequency of each area on the outer surface of the hoop through the sensor, and the vibration frequency of a certain area is the regional vibration frequency. The outer surface of the hoop may refer to the surface of the hoop that is not in contact with the battery cell of the battery module, or the surface of the hoop that is exposed in the battery module. The area where each sensor collects the vibration frequency may be located at any position of the hoop, such as in the middle of the hoop, such as in the middle of the hoop. Figure 2 The position between the two dotted lines.

[0048] After obtaining the regional vibration frequencies of multiple regions, the vibration frequency of the clamp can be determined according to the vibration frequencies of each region. For example, the mode of the vibration frequencies of each region is determined as the vibration frequency of the clamp; or the average value of the vibration frequencies of each region is determined as the vibration frequency of the clamp. This makes the obtained vibration frequency of the clamp more consistent with the actual situation, improves the accuracy of the internal expansion force determined by the vibration frequency later, and further improves the accuracy of the expansion detection of the battery module.

[0049] In order to further improve the accuracy of expansion detection of the battery module, in some embodiments, the vibration frequency of the clamp is determined according to the vibration frequency of each of the regions, including: determining the vibration frequency of the clamp according to the frequency peak value of the vibration frequency of each of the regions.

[0050] In some embodiments, by performing tensile tests on multiple samples of the same clamp as the clamp with different tensile forces, the vibration frequencies of the clamp under different tensile forces can be determined. Through the tensile test, it can be determined that the tensile force of the clamp is positively correlated with the vibration frequency of the clamp, that is, the greater the tensile force on the clamp, the higher the vibration frequency of the clamp.

[0051] When the clamp is stretched due to the internal expansion force of the battery module, different regions may be subjected to different stretching forces, and the region subjected to the greatest stretching force is most affected by the internal expansion force, so the stretching force in this region can better reflect the actual situation of the internal expansion force. Since the stretching force of the clamp is positively correlated with the vibration frequency of the clamp, the vibration frequencies of each region can be compared, and the maximum regional vibration frequency, that is, the frequency peak, can be determined from the vibration frequencies of each region, so that the frequency peak can be determined as the vibration frequency of the clamp.

[0052] Since the tensile force corresponding to the frequency peak in the vibration frequency of each component is most affected by the internal expansion force of the battery module compared to the tensile force corresponding to the vibration frequency of other areas, and can better reflect the actual situation of the internal expansion force, the frequency peak is determined as the vibration frequency of the fastener, so that the obtained vibration frequency of the fastener can more accurately reflect the influence of the internal swelling force on the vibration frequency of the fastener, thereby making the obtained vibration frequency of the fastener more in line with the actual situation, improving the accuracy of the subsequent internal expansion force determined by the vibration frequency, and further improving the accuracy of expansion detection of the battery module.

[0053] After the vibration frequency of the clamp is obtained, the vibration frequency can be compared with a mapping table recording the corresponding relationship between each vibration frequency and each tensile force to determine the tensile force corresponding to the vibration frequency as the tensile force on the clamp.

[0054] In order to avoid an excessive amount of data recorded in the mapping table, and to avoid the inability to detect the internal expansion force of the battery module due to the inability to find the stretching force that matches the vibration frequency of the fastener, in some embodiments, the stretching force exerted on the fastener is determined according to the vibration frequency of the fastener, including: inputting the vibration frequency of the fastener into a fitting model that represents the corresponding relationship between the vibration frequency and the stretching force, to determine the stretching force exerted on the fastener; wherein the fitting model is determined by the vibration frequency of the fastener under different stretching forces.

[0055] In some embodiments, multiple fastener samples that are the same as the fastener may be subjected to tensile tests using different tensile forces in advance to obtain the vibration frequencies corresponding to each fastener sample under different tensile forces, so that the vibration frequencies corresponding to each fastener sample under different tensile forces can be determined as the vibration frequencies corresponding to the fastener under different tensile forces.

[0056] After obtaining the vibration frequencies corresponding to the tightening member under different tensile forces, function fitting or curve fitting can be performed on the corresponding relationship between each tensile force and each vibration frequency to obtain a fitting model representing the corresponding relationship between the vibration frequency and the tensile force.

[0057] For example, taking the steel belt as the clamping member, after determining the vibration frequency of the steel belt under different tensile forces through a tensile test of 0-28000N, a curve fitting can be performed on the vibration frequency under different tensile forces to obtain a curve representing the corresponding relationship between the vibration frequency and the tensile force as a fitting model, such as Figure 3 Alternatively, a function fitting can be performed on the vibration frequencies corresponding to different stretching forces to obtain a function representing the functional relationship between the vibration frequency and the stretching force as a fitting model.

[0058] After obtaining the fitting model representing the corresponding relationship between the vibration frequency and the tensile force, the vibration frequency of the clamping member can be input into the fitting model to determine the tensile force output by the fitting model as the tensile force exerted on the clamping member.

[0059] By inputting the vibration frequency of the clamp into a fitting model representing the corresponding relationship between the vibration frequency and the tensile force, the tensile force on the clamp is determined. Therefore, when the tensile force on the clamp needs to be determined, it is not necessary to determine it by searching for data, which reduces the situation where the tensile force corresponding to the vibration frequency of the clamp cannot be obtained by searching for data, and improves the efficiency of obtaining the tensile force. Moreover, by determining the tensile force on the clamp by fitting the model, the determined tensile force can be more accurate, and the accuracy of subsequent expansion detection of the battery module using the tensile force can be improved.

[0060] After determining the tensile force exerted on the clamp, the tensile force can be determined as the internal expansion force of the battery module. In order to further improve the accuracy of the internal expansion force obtained, in some embodiments, the internal expansion force of the battery module is obtained according to the tensile force exerted on the clamp, including: obtaining the internal expansion force of the battery module according to the preset expansion force corresponding to the target tensile force matching the tensile force among the preset tensile forces; wherein the preset tensile force corresponding to any of the preset expansion forces is determined according to the tensile force of the clamp when the internal expansion force of the battery module is the preset expansion force.

[0061] In some embodiments, a plurality of battery module samples with pressure sensors implanted therein may be subjected to different numbers of charge and discharge cycles. The battery module sample is a battery pack identical to the battery module. After a plurality of battery module samples are subjected to different numbers of charge and discharge cycles, the internal expansion force of any battery module sample is recorded by a pressure sensor. At the same time, the tensile force corresponding to the clamping member of the battery module sample at this time is recorded, such as measuring the vibration frequency of the clamping member of the battery module sample, and inputting the vibration frequency of the clamping member of the battery module sample into the fitting model to obtain the tensile force corresponding to the clamping member of the battery module sample at this time. Thus, the corresponding relationship between the internal expansion force of each battery module sample and the tensile force of the clamping member of each battery module sample can be obtained.

[0062] The internal expansion force of each battery module sample is recorded as the preset expansion force, and the tensile force of the clamp of each battery module sample is recorded as the preset tensile force in the data table, so as to obtain a data table recording the corresponding relationship between the preset expansion forces of the battery module and the preset tensile force of the clamp of the battery module.

[0063] Exemplarily, four battery module samples with pressure sensors implanted inside can be subjected to 100, 500, 1000 and 5000 charge and discharge cycles respectively, and then the pressure sensor is used to record the internal expansion force of the first battery module sample after 100 charge and discharge cycles and the tensile force corresponding to the clamp of the first battery module sample at this time. Similarly, the internal expansion force of the remaining three battery module samples after the corresponding number of discharge cycles and the tensile force corresponding to the clamp of the battery module sample at this time can be obtained. In this way, the corresponding relationship between the internal expansion force of each battery module sample and the tensile force of the clamp of each battery module sample can be obtained, and the expansion force is recorded as the preset expansion force, and the tensile force is recorded as the preset tensile force in the data table, so that a data table recording the corresponding relationship between each preset expansion force of the battery module and the preset tensile force of the clamp of the battery module can be obtained.

[0064] After obtaining the tensile force of the battery module, the preset tensile force equal to the tensile force can be obtained from the data table as the target tensile force, and the preset expansion force corresponding to the target tensile force is used as the internal expansion force of the battery module. In this way, the internal expansion force of the battery module obtained can be more consistent with the actual situation, thereby improving the accuracy of the obtained internal expansion force.

[0065] In order to avoid the inability to detect the internal expansion force of the battery module due to the inability to find the target tensile force that matches the tensile force of the clamp, in some embodiments, the internal expansion force of the battery module is obtained according to the tensile force applied to the clamp, including: inputting the tensile force into a preset model representing the correspondence between the tensile force and the internal expansion force to obtain the internal expansion force of the battery module; wherein the preset model is determined by the tensile force corresponding to the clamp under different internal expansion forces of the battery module.

[0066] In some embodiments, after obtaining the corresponding relationship between the internal expansion force of each battery module sample and the tensile force of the clamping member of each battery module sample through testing, the corresponding relationship between each internal expansion force and each tensile force can be subjected to function fitting or curve fitting based on the corresponding relationship between each internal expansion force and each tensile force, so as to obtain a preset model representing the corresponding relationship between the tensile force of the clamping member of the battery module and the internal expansion force of the battery module.

[0067] After obtaining a preset model representing the corresponding relationship between the tensile force and the internal expansion force, the tensile force of the clamping member can be input into the preset model to determine the internal expansion force output by the preset model as the internal expansion force of the battery module.

[0068] By inputting the tensile force on the clamp into a preset model representing the corresponding relationship between the tensile force and the internal expansion force, the internal expansion force of the battery module is obtained. Therefore, when the internal expansion force of the battery module needs to be determined, it is not necessary to determine it by searching for data, which reduces the situation where the internal expansion force corresponding to the tensile force cannot be obtained by searching for data, and improves the efficiency of obtaining the internal expansion force. In addition, by determining the internal expansion force of the battery module through the preset model, the determined internal expansion force can be more accurate, thereby improving the accuracy of the expansion detection of the battery module.

[0069] After obtaining the internal expansion force of the battery module, it can be determined whether the battery module has abnormal expansion based on the internal expansion force. For example, it can be detected whether the internal expansion force is greater than the preset expansion force. If so, it indicates that the battery module has abnormal expansion. Considering that when the battery module has abnormal expansion, it may squeeze other components of the battery module and cause deformation, such as causing the conductive components connected to the battery cells in the battery module, such as the bus, to expand and deform, affecting the reliability of the components. To this end, in some embodiments, the method further includes: determining that the battery module has abnormal expansion based on the internal expansion force of the battery module, and obtaining the component vibration frequency of the components in the battery module; and determining the expansion detection result of the components based on the component vibration frequency of the components.

[0070] In some embodiments, the internal expansion force of the battery module may be compared with a preset expansion force to determine whether the battery module has abnormal expansion. The preset expansion force may be set according to actual conditions.

[0071] If the internal expansion force of the battery module is greater than the preset expansion force, it can be determined that the battery module has abnormal expansion. At this time, the vibration frequency of the component can be obtained through a sensor provided on the outer surface of the component in the battery module, such as a vibration sensor. The component may include a conductive component or a connecting component between battery cells, such as a copper bar, an aluminum bar, a copper-aluminum composite bar, or a busbar.

[0072] As a possible implementation, after obtaining the component vibration frequency of the component, the tensile force to which the component is subjected can be determined according to the component vibration frequency of the component. For example, different tensile forces can be used to perform tensile tests on component samples that are the same as the component in advance, and the component vibration frequencies corresponding to the component samples under different tensile forces can be detected to obtain the corresponding relationship between each tensile force and each component vibration frequency. After obtaining the component vibration frequency of the component in the battery module, the tensile force corresponding to the component vibration frequency can be determined as the tensile force to which the component is subjected.

[0073] After obtaining the tensile force on the component, the tensile force can be compared with the tensile force threshold. The tensile force threshold can be set according to the actual situation. For example, the tensile force critical value that causes the component to expand and deform, that is, the minimum tensile force that can cause the component to expand and deform, can be used as the tensile force threshold. If the tensile force on the component is greater than or equal to the tensile force critical value, it may cause the component to expand and deform. At this time, the expansion detection result of the component can be determined as the component has expanded and deformed; otherwise, the expansion detection result of the component can be determined as the component has not expanded and deformed.

[0074] By determining whether the battery module has abnormal expansion based on the internal expansion force of the battery module, the vibration frequency of the components in the battery module is obtained, and the expansion detection results of the components are determined based on the vibration frequency of the components. This allows the reliability of the components in the battery module to be effectively evaluated when the battery module has abnormal expansion.

[0075] In order to improve the efficiency of evaluating the reliability of components in a battery module, in some embodiments, an expansion detection result of the component is determined based on the component vibration frequency of the component, including: comparing the component vibration frequency of the component with the initial vibration frequency of the component to obtain the expansion detection result of the component.

[0076] In some embodiments, when a battery module leaves the factory, the vibration frequency of a component of the battery module may be acquired through a sensor, and the vibration frequency may be recorded as the initial vibration frequency of the component.

[0077] After the component vibration frequency of the component is obtained, the component vibration frequency can be compared with the initial vibration frequency of the component. If the component vibration frequency is greater than the initial vibration frequency, it means that the component is stretched. At this time, the expansion detection result of the component can be determined as the component has expanded deformation; otherwise, the expansion detection result of the component can be determined as the component has not expanded deformation.

[0078] Alternatively, when the vibration frequency of the component is greater than the initial vibration frequency, the absolute value of the difference between the vibration frequency of the component and the initial vibration frequency can be detected. If the absolute value exceeds the threshold, it can be determined that the expansion detection result of the component is that the component has undergone expansion deformation; otherwise, it can be determined that the expansion detection result of the component is that the component has not undergone expansion deformation. The threshold can be set according to actual conditions, such as the absolute value of the difference between the maximum vibration frequency measured when the component does not undergo expansion deformation and the initial vibration frequency.

[0079] By comparing the component vibration frequency of the component with the initial vibration frequency of the component, the expansion detection result of the component is obtained, so that the reliability of the component can be quickly evaluated, thereby improving the evaluation efficiency of the component reliability.

[0080] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution in the present application will be described clearly and completely below. In some embodiments, Figure 4 As shown, the expansion detection method of the battery module includes: S201, obtaining regional vibration frequencies of multiple regions on the outer surface of a clamping member for clamping each battery cell in a battery module; S202, determining the vibration frequency of the clamping member according to the frequency peak value of the vibration frequency of each region; S203, inputting the vibration frequency of the clamping member into a fitting model representing the corresponding relationship between the vibration frequency and the tensile force, and determining the tensile force exerted on the clamping member; wherein the fitting model is determined by the vibration frequency corresponding to the clamping member under different tensile forces; S204, inputting the tensile force exerted on the clamp into a preset model representing the corresponding relationship between the tensile force and the internal expansion force to obtain the internal expansion force of the battery module; wherein the preset model is determined by the tensile force corresponding to the clamp under different internal expansion forces of the battery module.

[0081] In some embodiments, in addition to the above steps, the method further comprises: S205, determining that the battery module has abnormal expansion according to the internal expansion force of the battery module, and obtaining the component vibration frequency of the components in the battery module; S206, comparing the component vibration frequency of the component with the initial vibration frequency of the component to obtain the expansion detection result of the component.

[0082] Figure 5 A schematic structural block diagram of a battery module expansion detection device provided in an embodiment of the present application is shown. It should be understood that the device is Figure 1 as well as Figure 4 Corresponding to the method embodiment executed in, the steps involved in the aforementioned method can be executed. The specific functions of the device can be found in the description above. To avoid repetition, the detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in a memory in the form of software or firmware or solidified in the operating system (OS) of the device. Specifically, the device includes a frequency acquisition module 301, which is used to obtain the vibration frequency of the clamping member used to clamp each battery cell in the battery module; a stretching detection module 302, which is used to determine the stretching force exerted on the clamping member according to the vibration frequency of the clamping member; an expansion detection module 303, which is used to obtain the internal expansion force of the battery module according to the stretching force exerted on the clamping member.

[0083] In the technical solution of the embodiment of the present application, the vibration frequency of the clamp used to clamp each battery cell in the battery module is obtained, and the tensile force on the clamp is determined according to the vibration frequency of the clamp, so as to obtain the internal expansion force of the battery module according to the tensile force on the clamp. Since the vibration frequency of the material is related to the stiffness coefficient of the material itself, when the expansion force is generated inside the battery module, the clamp will be squeezed and stretched, changing its stiffness coefficient, causing its vibration frequency to change. Therefore, the tensile force on the clamp due to battery expansion can be marked by the vibration frequency of the clamp, so as to use the tensile force to determine the internal expansion force of the battery module without disassembling the battery module, thereby improving the accuracy of expansion detection of the battery module.

[0084] According to some embodiments of the present application, the frequency acquisition module 301 is specifically used to: acquire regional vibration frequencies of multiple regions on the outer surface of the clamp; and determine the vibration frequency of the clamp according to the vibration frequencies of each region.

[0085] According to some embodiments of the present application, the frequency acquisition module 301 is specifically used to determine the vibration frequency of the tightening member according to the frequency peak value of the vibration frequency of each of the regions.

[0086] According to some embodiments of the present application, the stretching detection module 302 is specifically used to: input the vibration frequency of the fastening member into a fitting model representing the corresponding relationship between the vibration frequency and the stretching force, and determine the stretching force exerted on the fastening member; wherein the fitting model is determined by the vibration frequency corresponding to the fastening member under different stretching forces.

[0087] According to some embodiments of the present application, the expansion detection module 303 is specifically used to: obtain the internal expansion force of the battery module according to the preset expansion force corresponding to the target stretching force matching the stretching force among the preset stretching forces; wherein the preset stretching force corresponding to any of the preset expansion forces is determined according to the stretching force of the clamp when the internal expansion force of the battery module is the preset expansion force.

[0088] According to some embodiments of the present application, the expansion detection module 303 is specifically used to: input the tensile force into a preset model representing the correspondence between the tensile force and the internal expansion force, so as to obtain the internal expansion force of the battery module; wherein the preset model is determined by the tensile force corresponding to the tightening member under different internal expansion forces of the battery module.

[0089] According to some embodiments of the present application, the expansion detection module 303 is also used to: determine whether the battery module has abnormal expansion based on the internal expansion force of the battery module, and obtain the component vibration frequency of the components in the battery module; determine the expansion detection result of the component based on the component vibration frequency of the component.

[0090] According to some embodiments of the present application, the expansion detection module 303 is specifically used to: compare the component vibration frequency of the component with the initial vibration frequency of the component to obtain the expansion detection result of the component.

[0091] According to some embodiments of the present application, Figure 6 As shown, an embodiment of the present application provides an electronic device 4, including: a processor 401 and a memory 402, the processor 401 and the memory 402 are interconnected and communicate with each other through a communication bus 403 and / or other forms of connection mechanisms (not marked), the memory 402 stores a computer program executable by the processor 401, and when the computing device is running, the processor 401 executes the computer program to execute a method executed by an external terminal in any optional implementation method, for example: obtaining the vibration frequency of a clamping member for clamping each battery cell in a battery module; determining the tensile force exerted on the clamping member based on the vibration frequency of the clamping member; and obtaining the internal expansion force of the battery module based on the tensile force exerted on the clamping member.

[0092] The present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method in any of the aforementioned optional implementations is executed.

[0093] Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable red-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0094] The present application provides a computer program product. When the computer program product is run on a computer, the computer is enabled to execute the method in any optional implementation manner.

[0095] The present application provides a battery management system, on which a computer program is stored, and when the computer program is executed by a processor, the method in any optional implementation manner is implemented.

[0096] 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 them; although the present application has been described in detail with reference to the aforementioned embodiments, those of ordinary skill 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; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes those falling within the claims. All technical solutions within the scope.

Claims

1. A method for detecting expansion of a battery module, characterized in that: The method comprises: Obtaining the vibration frequency of a clamping member used to clamp each battery cell in the battery module; Determining the tensile force exerted on the tightening member according to the vibration frequency of the tightening member; The internal expansion force of the battery module is obtained according to the tensile force applied to the clamp.

2. The method according to claim 1, characterized in that: Obtaining the vibration frequency of a clamping member for clamping each battery cell in a battery module, including: Acquire regional vibration frequencies of multiple regions on the outer surface of the clamp; The vibration frequency of the clamping member is determined according to the vibration frequency of each region.

3. The method according to claim 2, characterized in that Determining the vibration frequency of the clamping member according to the vibration frequency of each region includes: The vibration frequency of the clamping member is determined according to the frequency peak value of the vibration frequency of each region.

4. The method according to claim 1, characterized in that: Determining the tensile force exerted on the clamping member according to the vibration frequency of the clamping member comprises: Inputting the vibration frequency of the clamping member into a fitting model representing the corresponding relationship between the vibration frequency and the tensile force to determine the tensile force exerted on the clamping member; Wherein, the fitting model is determined by the vibration frequency corresponding to the tightening member under different tensile forces.

5. The method according to any one of claims 1 to 4, characterized in that: The internal expansion force of the battery module is obtained according to the tensile force exerted on the clamp, including: Obtaining an internal expansion force of the battery module according to a preset expansion force corresponding to a target stretching force that matches the stretching force among the preset stretching forces; The preset tensile force corresponding to any of the preset expansion forces is determined according to the tensile force of the clamping member when the internal expansion force of the battery module is the preset expansion force.

6. The method according to any one of claims 1 to 4, characterized in that: The internal expansion force of the battery module is obtained according to the tensile force exerted on the clamp, including: Inputting the stretching force into a preset model representing the corresponding relationship between the stretching force and the internal expansion force to obtain the internal expansion force of the battery module; Wherein, the preset model is determined by the tensile force corresponding to the clamping member under different internal expansion forces of the battery module.

7. The method according to any one of claims 1 to 4, characterized in that: The method further comprises: Determining that the battery module has abnormal expansion according to the internal expansion force of the battery module, and obtaining the component vibration frequency of the components in the battery module; The expansion detection result of the component is determined according to the component vibration frequency of the component.

8. The method according to claim 7, characterized in that Determining the expansion detection result of the component according to the component vibration frequency of the component includes: The component vibration frequency of the component is compared with the initial vibration frequency of the component to obtain the expansion detection result of the component.

9. A battery module expansion detection device, characterized in that: The device comprises: A frequency acquisition module, used to acquire the vibration frequency of a clamping member used to clamp each battery cell in the battery module; A stretching detection module, used to determine the stretching force exerted on the clamping member according to the vibration frequency of the clamping member; The expansion detection module is used to obtain the internal expansion force of the battery module according to the tensile force applied to the clamp.

10. An electronic device comprising a processor and a memory storing a computer program, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

12. A battery management system having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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