Battery cell thermal runaway diagnosis method and device, sensor, automobile and storage medium

Abstract

The embodiment of the invention provides a battery cell thermal runaway diagnosis method and device, a sensor, an automobile and a storage medium, and relates to the technical field of battery safety. The method comprises the following steps: acquiring an MEMS resistance value of an MEMS gas sensor in real time by a detection unit of the MEMS gas sensor which is arranged in a battery pack of the electric vehicle and is connected with a battery management system of the electric vehicle; determining whether thermal runaway of the battery cell occurs in the battery pack or not by using the resistance value of each MEMS in the preset time window at the current moment; when it is determined that the battery cell thermal runaway occurs in the battery pack, a thermal runaway alarm signal is generated and transmitted to a battery management system, so that the battery management system uploads the thermal runaway alarm signal to a whole vehicle system of the electric vehicle, and the whole vehicle system prompts a user; and the thermal runaway of any battery cell in the battery pack can be timely detected and alarmed under any states of running, charging, static and the like of the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of battery safety technology, and in particular to a method, device, sensor, automobile and storage medium for diagnosing thermal runaway of a battery cell. Background Art

[0002] With the rapid development of the electric vehicle industry, OEMs around the world are committed to improving the safety of battery packs or systems. They are committed to providing a thermal event warning signal in advance before a single battery cell causes heat spread due to thermal runaway and then poses a threat to the passenger compartment, so as to ensure the safety of drivers and passengers.

[0003] At present, the main method to determine thermal runaway of battery cells is to use gas pressure sensors to monitor the rate of change of gas pressure. However, in cylindrical battery packs, when a single battery cell experiences thermal runaway, the layout of the gas pressure sensor may not accurately capture the pressure changes in the battery pack shell, resulting in the risk of missing thermal runaway faults. This situation urgently requires us to further optimize the detection technology to ensure the improvement of battery safety performance. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method and device for diagnosing thermal runaway of a battery cell, a MEMS gas sensor, an electric vehicle, and a computer-readable storage medium.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for diagnosing thermal runaway of a battery cell, which is applied to a detection unit of a MEMS gas sensor, wherein the MEMS gas sensor is installed inside a battery pack of an electric vehicle and connected to a battery management system of the electric vehicle, and the method comprises:

[0007] Acquire the MEMS resistance value of the MEMS gas sensor in real time;

[0008] Determine whether thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at the current moment;

[0009] When it is determined that thermal runaway of the battery cells occurs in the battery pack, a thermal runaway alarm signal is generated and transmitted to the battery management system, so that the battery management system uploads the thermal runaway alarm signal to the whole vehicle system of the electric vehicle, so that the whole vehicle system prompts the user.

[0010] Optionally, the step of determining whether thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at a current moment includes:

[0011] Using the steady-state value of the MEMS gas sensor to process each of the MEMS resistance values ​​that newly enters the preset time window at the current moment, obtain a MEMS resistance relative difference corresponding to each of the MEMS resistance values ​​that newly enters the preset time window at the current moment;

[0012] Whether thermal runaway of a battery cell occurs in the battery pack is determined by using a relative difference in MEMS resistance corresponding to the MEMS resistance value at a start time point and an end time point of the preset time window.

[0013] Optionally, the MEMS resistance relative difference corresponding to the MEMS resistance value satisfies the following formula:

[0014]

[0015] Wherein, V0 is the steady-state value of the MEMS gas sensor, V n is the MEMS resistance value, and d is the relative difference of the MEMS resistance.

[0016] Optionally, the step of determining whether thermal runaway of a battery cell occurs in the battery pack by using a relative difference in MEMS resistance corresponding to the MEMS resistance values ​​at a start time point and an end time point of the preset time window includes:

[0017] Calculating a relative difference slope using a MEMS resistance relative difference corresponding to the MEMS resistance value at a starting time point of the preset time window, a MEMS resistance relative difference corresponding to the MEMS resistance value at an ending time point of the preset time window, and a window length of the preset time window;

[0018] Whether thermal runaway of a battery cell occurs in the battery pack is determined according to the relative difference slope.

[0019] Optionally, the relative difference slope satisfies the following formula:

[0020]

[0021] Among them, d1 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the starting time point of the preset time window, d2 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the ending time point of the preset time window, t is the window length of the preset time window, and k is the relative difference slope.

[0022] Optionally, the step of determining whether thermal runaway of a battery cell occurs in the battery pack according to the relative difference slope includes:

[0023] If the relative difference slope is greater than a preset battery cell thermal runaway threshold, it is determined that a battery cell thermal runaway occurs in the battery pack;

[0024] If the relative difference slope is not greater than a preset battery cell thermal runaway threshold, it is determined that battery cell thermal runaway does not occur in the battery pack.

[0025] In a second aspect, the present invention provides a battery cell thermal runaway diagnostic device, which is applied to a detection unit of a MEMS gas sensor, wherein the MEMS gas sensor is installed inside a battery pack of an electric vehicle and connected to a battery management system of the electric vehicle, and the device comprises:

[0026] An acquisition module, used for acquiring the MEMS resistance value of the MEMS gas sensor in real time;

[0027] A determination module, used to determine whether a thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at a current moment;

[0028] The sending module is used to generate a thermal runaway alarm signal and transmit it to the battery management system when it is determined that thermal runaway of the battery cell occurs in the battery pack, so that the battery management system uploads the thermal runaway alarm signal to the whole vehicle system of the electric vehicle, so that the whole vehicle system prompts the user.

[0029] In a third aspect, the present invention provides a MEMS gas sensor, including a detection unit, wherein the detection unit is burned with machine executable instructions, and when the machine executable instructions are executed by the detection unit, the battery cell thermal runaway diagnosis method described in the first aspect is implemented.

[0030] In a fourth aspect, the present invention provides an electric vehicle, comprising a battery management system and a MEMS gas sensor as described in the third aspect above, connected to the battery management system.

[0031] In a fifth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a detection unit of a MEMS gas sensor, implements a method for diagnosing thermal runaway of a battery cell as described in any one of the aforementioned embodiments.

[0032] The battery cell thermal runaway diagnosis method provided by the embodiment of the present invention installs a MEMS gas sensor inside the battery pack of an electric vehicle and connects it to the battery management system of the electric vehicle. The detection unit of the MEMS gas sensor obtains the MEMS resistance value of the MEMS gas sensor in real time; uses each MEMS resistance value within the preset time window at the current moment to determine whether the battery cell thermal runaway occurs in the battery pack; when it is determined that the battery cell thermal runaway occurs in the battery pack, a thermal runaway alarm signal is generated and transmitted to the battery management system, so that the battery management system uploads the thermal runaway alarm signal to the whole vehicle system of the electric vehicle, so that the whole vehicle system prompts the user. Since the embodiment of the present invention installs a MEMS gas sensor capable of detecting and measuring specific gases or gas components in the environment in the battery pack, a data acquisition interface is provided for the MEMS gas sensor, the BMS, and the whole vehicle system, and the operating state of the battery pack is monitored and protected according to the real-time change of the MEMS resistance value of the MEMS gas sensor, so as to realize the timely detection and alarm of thermal runaway of any battery cell in the battery pack in any state such as running, charging, and stationary of the vehicle, and realize low-cost, highly integrated, all-weather battery cell thermal runaway safety protection to prevent heat diffusion.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A schematic block diagram of components of an electric vehicle provided by an embodiment of the present invention is shown;

[0036] Figure 2 A schematic flow chart of a method for diagnosing thermal runaway of a battery cell provided by an embodiment of the present invention is shown;

[0037] Figure 3 A schematic diagram of a thermal runaway test of a battery cell provided by an embodiment of the present invention is shown;

[0038] Figure 4 A functional unit block diagram of a battery cell thermal runaway diagnostic device provided by an embodiment of the present invention is shown.

[0039] Icons: 100-electric vehicle; 10-vehicle system; 20-battery management system; 30-MEMS gas sensor; 40-battery pack; 200-battery cell thermal runaway diagnostic device; 201-acquisition module; 202-determination module; 203-sending module. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0042] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article 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, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0043] like Figure 1 As shown, an embodiment of the present invention provides an electric vehicle 100, which includes a whole vehicle system 10, a battery management system 20, a MEMS gas sensor 30 and a battery pack 40, wherein the MEMS gas sensor 30 is installed inside the battery pack 40 of the electric vehicle 100 and connected to the battery management system 20 of the electric vehicle 100, and the battery management system 20 is connected to the whole vehicle system.

[0044] The MEMS gas sensor 30 includes a detection unit, and the battery cell thermal runaway diagnosis method provided in the embodiment of the present invention is applied to the detection unit, which will be described in detail below.

[0045] Please refer to Figure 2 The battery cell thermal runaway diagnosis method includes steps S101 to S103.

[0046] S101 , obtaining the MEMS resistance value of the MEMS gas sensor 30 in real time.

[0047] The MEMS gas sensor 30 is a miniaturized, integrated sensor manufactured using microelectronic processing technology, which can detect and measure specific gases or gas components in the environment.

[0048] In the embodiment of the present invention, by analyzing the gas components generated when the battery cell is in thermal runaway, a MEMS gas sensor 30 capable of detecting these characteristic gases, such as a MEMS H2 sensor, is selected and integrated into the battery pack.

[0049] The MEMS gas sensor 30 usually integrates one or more gas-sensitive materials, which are attached to the MEMS structure. When the gas-sensitive material comes into contact with molecules from the gas to be measured, its resistance value will change. This resistance change is detected by the detection unit and converted into an electrical signal, which is finally output as readable data.

[0050] It can be understood that the MEMS resistance value is the detected resistance value of the gas-sensitive material.

[0051] S102 , using the MEMS resistance values ​​within the preset time window at the current moment, determining whether thermal runaway of the battery cell occurs in the battery pack 40 .

[0052] In a possible implementation, step S102 may include sub-steps S102 - 1 to S102 - 2 .

[0053] S102-1, using the steady-state value of the MEMS gas sensor 30 to process each MEMS resistance value newly entering the preset time window at the current moment, to obtain a MEMS resistance relative difference corresponding to each MEMS resistance value newly entering the preset time window at the current moment.

[0054] The steady-state value of the MEMS gas sensor 30 refers to the resistance value when the gas-sensitive material is not in contact with molecules from the gas to be measured.

[0055] Each time the preset time window slides, a new MEMS resistance value enters the preset time window, and a previously entered MEMS resistance value exits the preset time window. For these newly entered MEMS resistance values, the steady-state value of the MEMS gas sensor 30 needs to be used to calculate their corresponding MEMS resistance relative differences.

[0056] It can be understood that the relative difference of the MEMS resistance can reflect the concentration of the gas to be measured in the battery pack 40 .

[0057] Since the corresponding MEMS resistance relative difference must be calculated for each MEMS resistance value when entering the preset time window, each MEMS resistance value in the preset time window has a corresponding preset time window.

[0058] Exemplarily, it is assumed that the preset time window slides once every 1 second. Each time it slides, a new MEMS resistance value enters the preset time window, and a previously entered MEMS resistance value exits the preset time window.

[0059] For each newly entered MEMS resistance value, the steady-state value of the MEMS gas sensor 30 is used for processing to obtain the MEMS resistance relative difference corresponding to each newly entered MEMS resistance value. The MEMS resistance relative difference corresponding to the MEMS resistance value satisfies the following formula:

[0060]

[0061] Wherein, V0 is the steady-state value of the MEMS gas sensor 30, V n is the MEMS resistance value, and d is the relative difference of MEMS resistance.

[0062] S102 - 2 , determining whether thermal runaway of a battery cell occurs in the battery pack 40 by using the relative difference in MEMS resistance corresponding to the MEMS resistance values ​​at the start time point and the end time point of the preset time window.

[0063] Optionally, the implementation process of step S102-2 may be:

[0064] S102-2-1, calculate the relative difference slope using the MEMS resistance relative difference corresponding to the MEMS resistance value at the starting time point of the preset time window, the MEMS resistance relative difference corresponding to the MEMS resistance value at the ending time point of the preset time window, and the window length of the preset time window.

[0065] Among them, the relative difference slope satisfies the following formula:

[0066]

[0067] Among them, d1 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the starting time point of the preset time window, d2 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the ending time point of the preset time window, t is the window length of the preset time window, and k is the relative difference slope.

[0068] S102-2-2: Determine whether thermal runaway of the battery cell occurs in the battery pack 40 based on the relative difference slope.

[0069] In an embodiment of the present invention, if the relative difference slope is greater than the preset cell thermal runaway threshold, it is determined that cell thermal runaway occurs in the battery pack 40 ; if the relative difference slope is not greater than the preset cell thermal runaway threshold, it is determined that cell thermal runaway does not occur in the battery pack 40 .

[0070] Among them, the preset battery cell thermal runaway threshold can be obtained through multiple test experiments.

[0071] The interior of the power battery pack used in new energy vehicles is a closed environment that meets the IP67 protection level. The detection value of the MEMS gas sensor 30 is relatively stable, and the relative difference slope K calculated by sliding the preset time window is approximately 0. When a thermal runaway event occurs in the battery cell, the steady-state environment is broken, and the relative difference slope K value calculated by sliding the preset time window will rise stepwise. When the K value is greater than the preset battery cell thermal runaway threshold, that is, 200, it is determined whether thermal runaway of the battery cell occurs in the battery pack 40, without being affected by single-point interference and environmental background noise.

[0072] S103, when it is determined that thermal runaway of the battery cells occurs in the battery pack 40, a thermal runaway alarm signal is generated and transmitted to the battery management system 20, so that the battery management system 20 uploads the thermal runaway alarm signal to the whole vehicle system 10 of the electric vehicle 100, so that the whole vehicle system 10 prompts the user.

[0073] In an embodiment of the present invention, the battery management system 20 receives the thermal runaway alarm signal uploaded by the MEMS gas sensor 30, and determines that thermal runaway has occurred, then uploads the alarm signal to the vehicle system 10 to prompt the user, and uploads it to the cloud backend alarm center to alert the original equipment manufacturer.

[0074] Based on the contents of the above embodiments, actual tests are performed, such as Figure 3 As shown, the blue line represents the relative difference slope calculated by the detection unit of the MEMS gas sensor 30 when the battery sends a thermal runaway signal, and the orange line represents the battery cell thermal runaway fault alarm flag. The flag is set to 1, which means that the battery management system 20 sends a battery cell thermal runaway alarm signal and sends a fault signal to the vehicle system 10. It can be seen that the battery cell thermal runaway diagnosis method provided in the embodiment of the present invention can realize timely detection and alarm of thermal runaway of any battery cell in the battery pack 40.

[0075] The present invention installs a MEMS gas sensor 30 inside the battery pack, and the detection unit of the MEMS gas sensor 30 runs the battery cell thermal runaway diagnosis method provided in the above embodiment, and provides a data acquisition interface between the MEMS gas sensor 30 and the battery management system 20 and the vehicle system 10, so as to monitor and protect the operating state of the battery pack 40, and realize timely detection and alarm of thermal runaway of any battery cell in the battery pack 40 when the vehicle is in any state such as running, charging and stationary. It realizes low-cost, highly integrated, all-weather battery cell thermal runaway safety protection and prevents heat diffusion.

[0076] In order to perform the corresponding steps in the above embodiments and various possible methods, a method for implementing a battery cell thermal runaway diagnosis device 200 is provided below. Figure 4 , Figure 4 This is a functional module diagram of a battery cell thermal runaway diagnostic device 200 provided in an embodiment of the present invention. It should be noted that the basic principle and technical effects of the battery cell thermal runaway diagnostic device 200 provided in this embodiment are the same as those of the above-mentioned embodiments. For the sake of brief description, for parts not mentioned in this embodiment, please refer to the corresponding contents in the above-mentioned embodiments. The battery cell thermal runaway diagnostic device 200 includes:

[0077] The acquisition module 201 is used to acquire the MEMS resistance value of the MEMS gas sensor 30 in real time.

[0078] The determination module 202 is used to determine whether thermal runaway of a battery cell occurs in the battery pack 40 by using each MEMS resistance value within a preset time window at the current moment.

[0079] The sending module 203 is used to generate a thermal runaway alarm signal and transmit it to the battery management system 20 when it is determined that thermal runaway of the battery cell occurs in the battery pack 40, so that the battery management system 20 uploads the thermal runaway alarm signal to the whole vehicle system 10 of the electric vehicle 100, so that the whole vehicle system 10 prompts the user.

[0080] Optionally, the determination module 202 is specifically used to process each MEMS resistance value that newly enters the preset time window at the current moment using the steady-state value of the MEMS gas sensor 30 to obtain a MEMS resistance relative difference corresponding to each MEMS resistance value that newly enters the preset time window at the current moment; and determine whether thermal runaway of the battery cell occurs in the battery pack using the MEMS resistance relative difference corresponding to the MEMS resistance values ​​at the start time point and the end time point of the preset time window; the MEMS resistance relative difference corresponding to the MEMS resistance value satisfies the following formula: Wherein, V0 is the steady-state value of the MEMS gas sensor 30, V n is the MEMS resistance value, and d is the relative difference of MEMS resistance.

[0081] Optionally, when the determination module 202 is used to determine whether thermal runaway of a battery cell occurs in the battery pack 40 by using the relative difference in MEMS resistance corresponding to the MEMS resistance value at the start time point and the end time point of the preset time window, it is specifically used to calculate the relative difference slope by using the relative difference in MEMS resistance corresponding to the MEMS resistance value at the start time point of the preset time window, the relative difference in MEMS resistance corresponding to the MEMS resistance value at the end time point of the preset time window, and the window length of the preset time window; determine whether thermal runaway of a battery cell occurs in the battery pack 40 according to the relative difference slope; the relative difference slope satisfies the following formula: Among them, d1 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the starting time point of the preset time window, d2 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the ending time point of the preset time window, t is the window length of the preset time window, and k is the relative difference slope.

[0082] Optionally, when the determination module 202 is used to determine whether thermal runaway of the battery cell occurs in the battery pack 40 based on the relative difference slope, it is specifically used to determine that thermal runaway of the battery cell occurs in the battery pack if the relative difference slope is greater than a preset thermal runaway threshold of the battery cell; if the relative difference slope is not greater than the preset thermal runaway threshold of the battery cell, it is determined that thermal runaway of the battery cell does not occur in the battery pack.

[0083] Optionally, the above modules can be stored in the form of software or firmware. Figure 1 The above modules are stored in the detection unit of the MEMS gas sensor and can be executed by the detection unit. Meanwhile, the data and program codes required to execute the above modules can be stored in the detection unit.

[0084] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0085] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0086] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for diagnosing thermal runaway of a battery cell, characterized in that: A detection unit applied to a MEMS gas sensor, wherein the MEMS gas sensor is installed inside a battery pack of an electric vehicle and connected to a battery management system of the electric vehicle, and the method comprises: Acquire the MEMS resistance value of the MEMS gas sensor in real time; Determine whether thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at the current moment; When it is determined that thermal runaway of the battery cells occurs in the battery pack, a thermal runaway alarm signal is generated and transmitted to the battery management system, so that the battery management system uploads the thermal runaway alarm signal to the whole vehicle system of the electric vehicle, so that the whole vehicle system prompts the user.

2. The battery cell thermal runaway diagnosis method according to claim 1, characterized in that: The step of determining whether thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at the current moment comprises: Using the steady-state value of the MEMS gas sensor to process each of the MEMS resistance values ​​that newly enters the preset time window at the current moment, obtain a MEMS resistance relative difference corresponding to each of the MEMS resistance values ​​that newly enters the preset time window at the current moment; Whether thermal runaway of a battery cell occurs in the battery pack is determined by using a relative difference in MEMS resistance corresponding to the MEMS resistance value at a start time point and an end time point of the preset time window.

3. The battery cell thermal runaway diagnosis method according to claim 2, characterized in that: The relative difference of the MEMS resistance corresponding to the MEMS resistance value satisfies the following formula: Wherein, V0 is the steady-state value of the MEMS gas sensor, V n is the MEMS resistance value, and d is the relative difference of the MEMS resistance.

4. The method for diagnosing thermal runaway of a battery cell according to claim 2, characterized in that: The step of determining whether thermal runaway of a battery cell occurs in the battery pack by using the relative difference of the MEMS resistance corresponding to the MEMS resistance value at the start time point and the end time point of the preset time window comprises: Calculating a relative difference slope using a MEMS resistance relative difference corresponding to the MEMS resistance value at a starting time point of the preset time window, a MEMS resistance relative difference corresponding to the MEMS resistance value at an ending time point of the preset time window, and a window length of the preset time window; Whether thermal runaway of a battery cell occurs in the battery pack is determined according to the relative difference slope.

5. The method for diagnosing thermal runaway of a battery cell according to claim 4, characterized in that: The relative difference slope satisfies the following formula: Among them, d1 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the starting time point of the preset time window, d2 is the relative difference of MEMS resistance corresponding to the MEMS resistance value at the ending time point of the preset time window, t is the window length of the preset time window, and k is the relative difference slope.

6. The method for diagnosing thermal runaway of a battery cell according to claim 4, characterized in that: The step of determining whether thermal runaway of a battery cell occurs in the battery pack according to the relative difference slope comprises: If the relative difference slope is greater than a preset battery cell thermal runaway threshold, it is determined that a battery cell thermal runaway occurs in the battery pack; If the relative difference slope is not greater than a preset battery cell thermal runaway threshold, it is determined that battery cell thermal runaway does not occur in the battery pack.

7. A battery cell thermal runaway diagnostic device, characterized in that: A detection unit for a MEMS gas sensor, wherein the MEMS gas sensor is installed inside a battery pack of an electric vehicle and connected to a battery management system of the electric vehicle, the device comprising: An acquisition module, used for acquiring the MEMS resistance value of the MEMS gas sensor in real time; A determination module, used to determine whether a thermal runaway of a battery cell occurs in the battery pack by using each MEMS resistance value within a preset time window at a current moment; The sending module is used to generate a thermal runaway alarm signal and transmit it to the battery management system when it is determined that thermal runaway of the battery cell occurs in the battery pack, so that the battery management system uploads the thermal runaway alarm signal to the whole vehicle system of the electric vehicle, so that the whole vehicle system prompts the user.

8. A MEMS gas sensor, characterized in that: It comprises a detection unit, the detection unit is burned with machine executable instructions, and when the machine executable instructions are executed by the detection unit, the battery cell thermal runaway diagnosis method according to any one of claims 1 to 6 is implemented.

9. An electric vehicle, characterized in that: The invention comprises a battery management system and the MEMS gas sensor as claimed in claim 8 connected to the battery management system.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the detection unit of the MEMS gas sensor, the battery cell thermal runaway diagnosis method according to any one of claims 1 to 6 is implemented.

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