Battery pack deformation detection method and device

Abstract

The embodiment of the invention provides a battery pack deformation detection method and device, and belongs to the technical field of battery safety, and the detection method comprises the steps: collecting air pressure data in a battery pack; determining an air pressure change curve according to the air pressure data in combination with steady-state air pressure; according to the air pressure change curve, in combination with a battery pack preset state characteristic quantity curve, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state; and when the state of the battery pack is an elastic deformation state, an irreversible deformation state or a damaged state, substituting the air pressure change curve into a function model, and determining the deformation. According to the detection method and device provided by the embodiment of the invention, whether the battery is deformed or not is judged by detecting the air pressure change state and the air pressure value in the battery pack, and the deformation amount is determined; the deformation of the battery pack can be automatically detected in real time, and an alarm is given to prompt a user when a safety risk is found.

Description

Technical Field

[0001] The present invention relates to the field of battery safety technology, and in particular to a battery pack deformation detection method and device. Background Art

[0002] With the rapid development of new energy and lithium battery technology, the application scenarios of lithium batteries have been further expanded, such as providing power for new energy vehicles and electric bicycles. In actual industrial production, battery packs consisting of multiple battery cells connected in series and parallel are usually used. The battery pack has a protective shell that can reduce the interference of the external environment on the internal battery.

[0003] When a battery pack is collided or squeezed, the risk of deformation of the battery pack shell and internal battery cells will increase. When the internal battery cells are deformed, it is easy to cause failures and affect the power supply. Existing battery risk detection usually uses the SOH battery health as the evaluation standard. In reality, there are cases where the battery is swollen but the SOH is normal. The deformation problem is ignored and early warning cannot be given. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a battery pack deformation detection method and device. The implementation of the present invention can solve or partially solve the problems existing in the prior art.

[0005] In order to achieve the above object, an embodiment of the present invention provides a battery pack deformation detection method, the detection method comprising:

[0006] Collect air pressure data inside the battery pack;

[0007] Determine an air pressure change curve based on the air pressure data and in combination with the steady-state air pressure;

[0008] According to the air pressure change curve, combined with the preset state characteristic curve of the battery pack, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state;

[0009] When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is substituted into the function model to determine the deformation amount.

[0010] Optionally, the steady-state air pressure is the air pressure value corresponding to when the battery pack is not deformed.

[0011] Optionally, the air pressure change curve is a two-dimensional curve, the abscissa is time, and the ordinate is the difference between the air pressure data in the battery pack and the steady-state air pressure;

[0012] The battery pack preset state characteristic quantity curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data corresponding to the battery pack state and the steady-state air pressure.

[0013] Optionally, the function model is established by deforming the battery pack in advance and using a data set of deformation and air pressure data:

[0014] According to the relationship between the volume and pressure of the internal gas before and after the deformation of the sealed battery pack, the volume change value ΔV of the gas is calculated, and the volume change value is the deformation amount of the battery pack;

[0015] ΔV=p1V1T2 / (p2T1)-V1

[0016] The pressure of the gas inside the battery pack before and after deformation is p1 and p2 respectively; the volume of the gas inside the battery pack before deformation is V1; the temperature of the gas inside the battery pack before and after deformation is T1 and T2 respectively. Optionally, the method further includes, when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, giving an alarm and / or disconnecting the battery pack.

[0017] In another aspect, the present invention provides a battery pack deformation detection device, the device comprising:

[0018] A battery pack deformation detection device, characterized in that the device comprises:

[0019] A collection module, used to collect air pressure data in the battery pack;

[0020] A processing module, used to determine an air pressure change curve according to the air pressure data and in combination with the steady-state air pressure;

[0021] According to the air pressure change curve, combined with the preset state characteristic curve of the battery pack, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state;

[0022] When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is brought into the function model to determine the deformation amount;

[0023] Output module, used to output battery pack status and deformation.

[0024] Optionally, the steady-state air pressure is the air pressure value corresponding to when the battery pack is not deformed.

[0025] Optionally, the air pressure change curve is a two-dimensional curve, the abscissa is time, and the ordinate is the difference between the air pressure data in the battery pack and the steady-state air pressure;

[0026] The battery pack preset state characteristic quantity curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data corresponding to the battery pack state and the steady-state air pressure.

[0027] Optionally, the function model is established by deforming the battery pack in advance and using a data set of deformation and air pressure data:

[0028] According to the relationship between the volume and pressure of the internal gas before and after the deformation of the sealed battery pack, the volume change value ΔV of the gas is calculated, and the volume change value is the deformation amount of the battery pack;

[0029] ΔV=p1V1T2 / (p2T1)-V1

[0030] The pressure of the gas inside the battery pack before and after deformation is p1 and p2 respectively; the volume of the gas inside the battery pack before deformation is V1; the temperature of the gas inside the battery pack before and after deformation is T1 and T2 respectively. Optionally, the processing module further includes: when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, an alarm is issued and / or the battery pack is powered off.

[0031] Through the above technical scheme, the embodiment of the present invention provides a battery pack deformation detection method and device, which determines whether the battery is deformed and the amount of deformation by detecting the air pressure change state and air pressure value in the battery pack; it can realize real-time automatic detection of battery pack deformation and alarm the user when safety risks are found.

[0032] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0034] Figure 1 is a flow chart of the detection method provided by the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of the detection device provided by the present invention;

[0036] Figure 3 It is the characteristic quantity curve diagram corresponding to the battery pack in a normal state;

[0037] Figure 4 It is the characteristic quantity curve corresponding to the elastic deformation of the battery pack;

[0038] Figure 5 It is the characteristic quantity curve corresponding to the irreversible deformation of the battery pack;

[0039] Figure 6 This is the corresponding characteristic quantity curve when the battery pack is damaged. DETAILED DESCRIPTION

[0040] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0041] Figure 1 is a flow chart of the detection method provided by the present invention; Figure 3 It is the characteristic quantity curve diagram corresponding to the battery pack in a normal state; Figure 4 It is the characteristic quantity curve corresponding to the elastic deformation of the battery pack;

[0042] Figure 5 It is the characteristic quantity curve corresponding to the irreversible deformation of the battery pack; Figure 6 This is the corresponding characteristic quantity curve when the battery pack is damaged.

[0043] like Figure 1 As shown, an embodiment of the present invention provides a battery pack deformation detection method, the detection method comprising:

[0044] S101, collecting air pressure data in the battery pack;

[0045] It should be noted that multiple battery cells are integrated in the battery pack, and the outer shell of the battery pack is dustproof and waterproof; the sampling frequency can be set, and the air pressure sensor can be used to collect the air pressure data in the battery pack according to the preset sampling frequency, and the air pressure sensor can be installed at any position in the battery pack; wherein the material of the battery cell can be lithium iron phosphate, lithium manganese oxide, or sodium ion.

[0046] S102, determining an air pressure change curve according to the air pressure data and in combination with the steady-state air pressure;

[0047] Among them, the steady-state air pressure is the corresponding air pressure value when the battery pack is not deformed;

[0048] The air pressure change curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data in the battery pack and the steady-state air pressure.

[0049] It should be noted that due to the interference of altitude, temperature, speed and acceleration, there is a certain amount of noise in the air pressure change curve, and the air pressure change curve can be filtered to remove noise.

[0050] S103, determining the battery pack state according to the air pressure change curve and a preset battery pack state characteristic curve;

[0051] Wherein, the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state;

[0052] The characteristic curve of the preset state of the battery pack is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data corresponding to the battery pack state and the steady-state air pressure.

[0053] For example, when the pressure change curve is Figure 3 When the characteristic curve corresponds to the normal state, the battery pack is in a normal state; when the pressure change curve is Figure 4 When the characteristic curve in corresponds to , the battery pack is in an elastic deformation state, where a is the maximum air pressure value, and the deformation can be calculated based on the maximum air pressure value a; when the air pressure change curve, Figure 5 When the characteristic curve in corresponds to the state of irreversible deformation, the battery pack is in an irreversible deformation state, where b is the maximum air pressure value, and the deformation can be calculated based on the maximum air pressure value b; when the air pressure change curve corresponds to Figure 6 When the characteristic curve in corresponds to , the battery pack is in a damaged state, where c is the maximum air pressure value, and the deformation can be calculated based on the maximum air pressure value c.

[0054] S104. When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is brought into a function model to determine the deformation amount.

[0055] Furthermore, the function model is established by deforming the battery pack in advance and using a data set of deformation and air pressure data. Since the size, structure, and material of the battery pack shells of different products are different, it is necessary to design an experiment to determine the function model for calculating the deformation according to the air pressure value, such as building a battery pack deformation detection device, deforming the battery pack shell by artificial means, and establishing a function model for calculating the deformation according to the collected air pressure data.

[0056] For example, the volume change of the gas can be calculated based on the relationship between the volume and pressure of the internal gas before and after the deformation of the sealed battery pack, and the volume change is the deformation of the battery pack;

[0057] The gas state inside the battery pack satisfies the following ideal gas state equation before and after deformation:

[0058] p1V1=nRT1

[0059] p2V2=nRT2

[0060] Among them, the pressure of the gas inside the battery pack before and after deformation is p1 and p2 respectively; the volume of the gas inside the battery pack before and after deformation is V1 and V2 respectively; the temperature of the gas inside the battery pack before and after deformation is T1 and T2 respectively; n is the amount of gas substance; R is the molar gas constant, also called the universal gas constant;

[0061] The battery pack remains sealed. After the box is deformed, the volume and pressure of the internal gas change, but the gas mass remains unchanged, that is, n remains unchanged;

[0062] After deformation, the gas volume V2 inside the battery pack satisfies:

[0063] V2=p1V1T2 / (p2T1)

[0064] Then the volume change of the gas inside the battery pack, that is, the deformation of the battery pack ΔV, is obtained:

[0065] ΔV=p1V1T2 / (p2T1)-V1.

[0066] It should be noted that the detection method also includes, when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, issuing an alarm and / or cutting off the power to the battery pack.

[0067] For example, when the battery pack is in elastic deformation, the fault level is set to level 1; when the battery pack is in irreversible deformation, the fault level is set to level 2; when the battery pack is in damaged state, the fault level is set to level 3.

[0068] Correspondingly, when the fault level is greater than or equal to 1, the fault level will be announced by voice and the light will be indicated to remind the user; when the fault level is level 1 or level 2, the battery pack status and deformation amount can be pushed to the user; when the fault level is level 2, the BMS battery management system can be used to control the battery pack to limit power operation; when the fault level is level 3, the BMS battery management system can be used to control the battery pack to power off.

[0069] Figure 2 It is a schematic diagram of the structure of the detection device provided by the present invention, such as Figure 2 As shown, the device comprises:

[0070] A collection module, used to collect air pressure data in the battery pack;

[0071] Furthermore, the acquisition module can be an air pressure sensor installed inside the battery pack. The battery pack includes multiple battery cells integrated inside and a battery pack shell, and the battery pack is sealed inside. The air pressure sensor is used to monitor the air pressure value inside the battery pack in real time, and the air pressure sensor can be installed at any position inside the battery pack. The air pressure sensor transmits the collected air pressure data to the processing module for processing.

[0072] A processing module, used to determine an air pressure change curve according to the air pressure data and in combination with the steady-state air pressure;

[0073] According to the air pressure change curve, combined with the preset state characteristic curve of the battery pack, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state;

[0074] When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is brought into the function model to determine the deformation amount;

[0075] Furthermore, the processing module also includes, when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, issuing an alarm and / or cutting off the power of the battery pack.

[0076] It should be noted that the processing module can be implemented by a microcomputer, can be set on the outer surface of the battery pack shell, or can be set inside the battery pack. The processing module can also be connected to the sound and light alarm device, cloud platform, and BMS battery management system.

[0077] Correspondingly, when the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the processing module controls the sound and light alarm device to perform voice broadcast and light indication to broadcast the battery pack state and deformation amount;

[0078] When the battery pack is in an elastic deformation state or an irreversible deformation state, the processing module controls the cloud platform to push data to the user, including the battery pack state and deformation amount;

[0079] When the battery pack is in an irreversible deformation state, the processing module sends a signal to the BMS battery management system to control the battery pack to operate at limited power;

[0080] When the battery pack is in a severely deformed state, the processing module sends a signal to the BMS battery management system to control the battery pack to cut off power.

[0081] Furthermore, the processing module can control the sound and light alarm device to broadcast the remaining usable time of the battery pack before the battery pack is powered off; the processing module can control the cloud platform to push the remaining usable time of the battery pack to the user.

[0082] Output module, used to output battery pack status and deformation.

[0083] Correspondingly, the output module can be a user terminal, such as a smart speaker, mobile phone, smart watch, or car display, which can display the battery pack status, deformation amount, and remaining usable time; it can also be an audio and visual alarm device that broadcasts the battery pack status, deformation amount, and remaining usable time to prompt the user.

[0084] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0085] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0086] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0087] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0088] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0089] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0090] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0091] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0092] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A battery pack deformation detection method, characterized in that: The detection method comprises: Collect air pressure data inside the battery pack; Determine an air pressure change curve based on the air pressure data and in combination with the steady-state air pressure; According to the air pressure change curve, combined with the preset state characteristic curve of the battery pack, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state; When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is substituted into the function model to determine the deformation amount.

2. The method according to claim 1, characterized in that: The steady-state air pressure is the air pressure value corresponding to when the battery pack is not deformed.

3. The method according to claim 1, characterized in that The air pressure change curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data in the battery pack and the steady-state air pressure; The battery pack preset state characteristic quantity curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data corresponding to the battery pack state and the steady-state air pressure.

4. The method according to claim 1, characterized in that The function model is established by deforming the battery pack in advance and using a data set of deformation and air pressure data: According to the relationship between the volume and pressure of the internal gas before and after the deformation of the sealed battery pack, the volume change value ΔV of the gas is calculated, and the volume change value is the deformation amount of the battery pack; ΔV=p1V1T2 / (p2T1)-V1 Among them, the pressure of the gas inside the battery pack before and after deformation is p1 and p2 respectively; the volume of the gas inside the battery pack before deformation is V1; the temperature of the gas inside the battery pack before and after deformation is T1 and T2 respectively.

5. The method according to claim 1, characterized in that The method also includes, when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, issuing an alarm and / or cutting off the power to the battery pack.

6. A battery pack deformation detection device, characterized in that: The device includes: A collection module, used to collect air pressure data in the battery pack; A processing module, used to determine an air pressure change curve according to the air pressure data and in combination with the steady-state air pressure; According to the air pressure change curve, combined with the preset state characteristic curve of the battery pack, the battery pack state is determined, and the battery pack state is a normal state, an elastic deformation state, an irreversible deformation state or a damaged state; When the battery pack is in an elastic deformation state, an irreversible deformation state or a damaged state, the air pressure change curve is brought into the function model to determine the deformation amount; Output module, used to output battery pack status and deformation.

7. The device according to claim 6, characterized in that The steady-state air pressure is the air pressure value corresponding to when the battery pack is not deformed.

8. The device according to claim 6, characterized in that The air pressure change curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data in the battery pack and the steady-state air pressure; The battery pack preset state characteristic quantity curve is a two-dimensional curve, the horizontal axis is time, and the vertical axis is the difference between the air pressure data corresponding to the battery pack state and the steady-state air pressure.

9. The device according to claim 6, characterized in that The function model is established by deforming the battery pack in advance and using a data set of deformation and air pressure data: According to the relationship between the volume and pressure of the internal gas before and after the deformation of the sealed battery pack, the volume change value ΔV of the gas is calculated, and the volume change value is the deformation amount of the battery pack; ΔV=p1V1T2 / (p2T1)-V1 Among them, the pressure of the gas inside the battery pack before and after deformation is p1 and p2 respectively; the volume of the gas inside the battery pack before deformation is V1; the temperature of the gas inside the battery pack before and after deformation is T1 and T2 respectively.

10. The device according to claim 6, characterized in that The processing module further includes: when the battery pack is in a damaged state or the determined deformation amount is equal to or greater than a preset value, giving an alarm and / or cutting off the power of the battery pack.

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