Battery thermal runaway analysis method, battery module and automobile

Abstract

The invention relates to the technical field of new energy automobiles, in particular to a battery thermal runaway analysis method, a battery module and an automobile. The battery thermal runaway analysis method comprises the following steps: designing the size of a test box body according to the volume of a battery module; performing simulation transformation on the test box body according to the internal and external environment information of the test box body; installing temperature sensors on a plurality of cylindrical battery cells of the battery module; performing thermal runaway triggering on one or more cylindrical battery cells, monitoring test data of the triggered cylindrical battery cell and test data of cylindrical battery cells around the triggered cylindrical battery cell in real time, and comparing the monitored test data with empirical data; and carrying out modification design on the battery module according to a data comparison result. According to the battery thermal runaway analysis method, the battery module and the automobile provided by the invention, the problem that a traditional battery module thermal runaway analysis method does not consider whether the surrounding cylindrical battery cells are influenced or not after thermal runaway of one or more cylindrical battery cells is solved.

Description

Technical Field

[0001] The present application relates to the technical field of new energy vehicles, and in particular to a battery thermal runaway analysis method, a battery module and a vehicle. Background Art

[0002] With the rapid popularization of electric vehicles, consumers and automakers are paying more and more attention to battery safety issues. Power batteries are not only the main power source and core components of electric vehicles, but also the main technical barrier to their rapid development. Lithium batteries are widely used in mobile phones, electric vehicles, mobile power supplies and other fields due to their high energy density, high cycle life and high environmental protection.

[0003] However, safety accidents such as lithium battery fires caused by thermal runaway and battery management systems have become a huge challenge for the development of new energy vehicles. According to statistics, there were 640 fires in new energy vehicles in my country in the first quarter of 2022, with an average of 7 new energy vehicles catching fire every day (including spontaneous combustion). The combustion of lithium-ion batteries is accompanied by a large amount of heat and gas, which is not only prone to explosion, but also produces a large amount of harmful gases during the combustion process, such as olefins, alkanes, ethers, hydrogen fluoride and other compounds, posing a threat to people's lives and property safety.

[0004] Therefore, it is very important to study and test the thermal runaway management of batteries. Taking the cylindrical battery cell battery module as an example, the traditional thermal runaway analysis of battery modules is to disassemble and analyze the samples after the thermal runaway of the cylindrical battery cell, and make relevant improvements to the cylindrical battery cell based on the analysis results.

[0005] However, the prior art does not take into account the impact of one or more cylindrical cells in the battery module on the surrounding cylindrical cells after thermal runaway, that is, it does not take into account whether the design of the entire battery module is reasonable. If the design of the entire battery module is unreasonable, when one or more cylindrical cells in the battery module thermally runaway, it will cause a safety accident in the entire battery module. The prior art does not take this into account. Summary of the invention

[0006] The purpose of the present application is to provide a battery thermal runaway analysis method, a battery module and a vehicle, thereby solving the problem that the traditional battery module thermal runaway analysis method does not take into account the rationalization of the entire battery module design, that is, it does not take into account whether the surrounding cylindrical battery cells will be affected when one or more cylindrical battery cells have thermal runaway.

[0007] According to a first aspect of the present application, a battery thermal runaway analysis method is provided, comprising:

[0008] The test box size design steps are as follows: the size of the test box is designed according to the volume of the battery module;

[0009] The test box simulation design steps include: performing simulation transformation on the test box according to the internal and external environment information of the test box;

[0010] Testing equipment installation steps, installing temperature sensors on multiple cylindrical cells of the battery module;

[0011] The test step includes triggering thermal runaway of one or more cylindrical cells, monitoring the test data of the triggered cylindrical cells and the test data of the cylindrical cells around the triggered cylindrical cells in real time, and comparing the monitored test data with the empirical data;

[0012] Analyze the modification steps and modify the design of the battery module based on the data comparison results.

[0013] In any of the above technical solutions, further, the test box simulation design step includes:

[0014] According to the position of the battery module and the internal and external pressures of the test box, a pressure relief valve is installed on the test box;

[0015] The steps for installing the testing equipment include:

[0016] Divide the multiple cylindrical cells of the battery module into multiple test areas, and install temperature sensors on the multiple cylindrical cells in each test area;

[0017] The experimental test steps include:

[0018] In each test area, thermal runaway is triggered for a cylindrical battery cell, and the test data of the currently triggered cylindrical battery cell and the test data of the cylindrical battery cells around the triggered cylindrical battery cell are monitored in real time, and the monitored test data is compared with the empirical data.

[0019] In any of the above technical solutions, further, after the battery module is modified and designed, the detection equipment installation step, the experimental test step and the analysis and modification step are repeated;

[0020] The battery module after the modified design includes a plurality of cylindrical cells, the plurality of cylindrical cells are divided into a plurality of rows, and the plurality of cylindrical cells in any two adjacent rows are staggered;

[0021] The steps for installing the testing equipment include:

[0022] The multiple cylindrical cells of the battery module are divided into multiple test areas, some of which are hexagonal. Among the multiple cylindrical cells in the hexagonal test area, the cylindrical cell at the center is the thermal runaway triggering cell;

[0023] Part of the test area is the corner area of ​​the battery module. Among the multiple cylindrical battery cells in the corner area, the cylindrical battery cells at the corner are thermal runaway triggering cells.

[0024] In any of the above technical solutions, further, after the battery module is modified and designed, the detection equipment installation step, the experimental test step and the analysis and modification step are repeated;

[0025] The battery module after the modified design also includes two liquid cooling plates, and the multiple cylindrical cells are divided into four rows, and the multiple cylindrical cells in any two adjacent rows are staggered;

[0026] A liquid cooling plate is arranged between the first row of cylindrical battery cells and the second row of cylindrical battery cells, and a liquid cooling plate is arranged between the third row of cylindrical battery cells and the fourth row of cylindrical battery cells. A water inlet is arranged at the first end of each of the liquid cooling plates, and a water outlet is arranged at the second end of each of the liquid cooling plates.

[0027] In any of the above technical solutions, further, after the battery module is modified and designed, the detection equipment installation step, the experimental test step and the analysis and modification step are repeated;

[0028] The battery module after the modified design also includes a water inlet pipe and a water outlet pipe, and the liquid cooling plate is corrugated;

[0029] The battery module has a width direction and a height direction. The water inlet pipe is introduced into the test box from the width direction and connected to the water inlets of the two liquid cooling plates. The water outlet pipe is introduced into the test box from the width direction and connected to the water outlets of the two liquid cooling plates.

[0030] In any of the above technical solutions, further, after the battery module is modified and designed, the detection equipment installation step, the experimental test step and the analysis and modification step are repeated;

[0031] The battery module with modified design also includes an exhaust channel, which is arranged at the bottom of the battery module and is provided with a through hole for installing the cylindrical battery cell.

[0032] In any of the above technical solutions, further, after the battery module is modified and designed, the detection equipment installation step, the experimental test step and the analysis and modification step are repeated;

[0033] The battery module after the modified design also includes thermal insulation glue, and the thermal insulation glue is arranged between adjacent cylindrical battery cells.

[0034] In any of the above technical solutions, further, the test box includes a lower box and a cover, and the lower box and the cover are both made of metal;

[0035] The cover head is connected to the upper edge of the lower box body by bolts, a sealing strip is arranged between the upper edge of the lower box body and the cover body, and the bolts can pass through the sealing strip.

[0036] In any of the above technical solutions, further, the experimental testing step also includes:

[0037] Thermal runaway is triggered by heating, puncturing or squeezing the cylindrical battery cells through a heating sheet.

[0038] In any of the above technical solutions, further, the battery thermal runaway analysis method also includes a secondary inspection test step after the battery module design is modified to meet the requirements:

[0039] In the secondary inspection test step, thermal runaway is continued to be triggered on one or more cylindrical battery cells. When the triggered cylindrical battery cell has thermal runaway, if the detection data of the adjacent cylindrical battery cell does not meet the requirements, the parameters of the cylindrical battery cell are modified and designed.

[0040] According to a second aspect of the present application, a battery module is provided, and the battery module is obtained by analyzing the battery thermal runaway analysis method as described above.

[0041] In any of the above technical schemes, further, the battery module includes a plurality of cylindrical battery cells and two liquid cooling plates, the plurality of cylindrical battery cells are divided into four rows, and the plurality of cylindrical battery cells in any two adjacent rows are staggered; one liquid cooling plate is arranged between the first row of cylindrical battery cells and the second row of cylindrical battery cells, and one liquid cooling plate is arranged between the third row of cylindrical battery cells and the fourth row of cylindrical battery cells, a water inlet is arranged at the first end of each of the liquid cooling plates, and a water outlet is arranged at the second end of each of the liquid cooling plates; the battery module also includes a water inlet pipe and a water outlet pipe, and the liquid cooling plate is corrugated; the battery module has a width direction and a height direction, the water inlet pipe is introduced into the test box from the width direction and is connected to the water inlets of the two liquid cooling plates, and the water outlet pipe is introduced into the test box from the width direction and is connected to the water outlets of the two liquid cooling plates.

[0042] In any of the above technical solutions, further, the battery module also includes an exhaust channel, which is arranged at the bottom of the battery module, and the exhaust channel is provided with a through hole for installing the cylindrical battery cell; the battery module also includes thermal insulation glue, and thermal insulation glue is arranged between adjacent cylindrical battery cells.

[0043] According to a third aspect of the present application, a car is provided, comprising the battery module as described above.

[0044] In any of the above technical solutions, further, when the battery module is installed in the car, the exhaust channel of the battery module is located at the bottom of the battery module.

[0045] The battery thermal runaway analysis method of this application includes:

[0046] First, design the size of the test box according to the volume of the battery module.

[0047] Then, the test box is simulated and transformed according to the internal and external environment information of the test box.

[0048] Next, temperature sensors are installed on multiple cylindrical cells of the battery module.

[0049] Next, thermal runaway is triggered on one or more cylindrical battery cells, and test data of the triggered cylindrical battery cells and test data of cylindrical battery cells around the triggered cylindrical battery cells are monitored in real time, and the monitored test data are compared with the empirical data.

[0050] Finally, the battery module design is modified based on the data comparison results.

[0051] According to the above technical features, the beneficial effects of this application are:

[0052] This application designs relevant battery modules and test boxes to simulate real power battery packs for testing. That is, to test the impact of thermal runaway of cylindrical cells on the surrounding areas. This application develops the entire process of thermal safety performance of cylindrical batteries, and monitors the test data of the triggered cylindrical cells and the test data of the cylindrical cells around the triggered cylindrical cells in real time, and compares the monitored test data with the empirical data, performs correlation analysis based on the mapping relationship, and modifies the design of the battery module based on the experimental results. For example, when the monitored test data does not meet the standards compared with the empirical data, the arrangement of the cylindrical cells can be modified, liquid cooling plates can be added, thermal insulation glue can be added, or heat dissipation gaps can be added.

[0053] The battery thermal runaway analysis method of the present application can accurately analyze the dynamic evolution mode of thermal runaway, conduct real-time testing and analysis, and make real-time modifications until the modified battery module meets the standards, at which time the test can be stopped. The battery thermal runaway analysis method of the present application can simulate whether the design of the entire battery module is reasonable, so as to reduce the impact of thermal runaway of one or more cylindrical cells on the surrounding cylindrical cells, thereby reducing the safety accidents of the entire battery module.

[0054] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application 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 paying creative work.

[0056] Figure 1A schematic diagram showing the overall structure of a test box according to an embodiment of the present application;

[0057] Figure 2 A schematic diagram showing the installation structure of a battery module according to an embodiment of the present application;

[0058] Figure 3 Show Figure 2 A structural diagram from another perspective;

[0059] Figure 4 Show Figure 6 Schematic diagram of the structure after hiding the cylindrical battery cell;

[0060] Figure 5 Show Figure 4 A structural diagram from another perspective;

[0061] Figure 6 A schematic diagram showing the overall structure of a battery module according to an embodiment of the present application;

[0062] Figure 7 A schematic diagram showing the distribution of the test area of ​​the battery module of an embodiment of the present application;

[0063] Figure 8 A schematic diagram showing the temperature change of a cylindrical battery cell.

[0064] Icons: 100-test box; 101-lower box; 102-cover; 103-pressure relief valve installation part; 104-sealing strip; 200-cylindrical battery cell; 300-liquid cooling plate; 301-water inlet pipe; 302-water outlet pipe; 400-fixing frame; 500-exhaust channel; 501-through hole; 10-hexagonal test area; 20-corner area. DETAILED DESCRIPTION

[0065] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0066] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0067] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0068] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0069] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0070] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0071] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0072] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0073] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0074] Taking cylindrical battery modules as an example, traditional thermal runaway analysis of battery modules involves disassembling and analyzing samples of cylindrical batteries after thermal runaway, and making related improvements to the cylindrical batteries based on the analysis results. However, the prior art does not take into account the impact of thermal runaway of one or more cylindrical batteries on the surrounding cylindrical batteries, that is, it does not take into account whether the design of the entire battery module is reasonable. If the design of the entire battery module is unreasonable, thermal runaway of one or more cylindrical batteries will cause safety accidents in the entire battery module, which is not considered in the prior art.

[0075] In view of this, the first aspect of the present application provides a battery thermal runaway analysis method to solve the technical problems existing in the prior art. Figures 1 to 8 The battery thermal runaway analysis method and battery module of the present application are described in detail.

[0076] The battery thermal runaway analysis method of this application includes:

[0077] First, design the size of the test box according to the volume of the battery module.

[0078] Then, the test box 100 is simulated and modified according to the internal and external environment information of the test box 100 .

[0079] Next, temperature sensors are installed on multiple cylindrical cells of the battery module.

[0080] Next, thermal runaway is triggered on one or more cylindrical battery cells, and test data of the triggered cylindrical battery cells and test data of cylindrical battery cells around the triggered cylindrical battery cells are monitored in real time, and the monitored test data are compared with the empirical data.

[0081] Finally, the battery module design is modified based on the data comparison results.

[0082] As mentioned above, the present application designs relevant battery modules and test boxes 100 to simulate real power battery packs for testing. That is, to test the impact of thermal runaway of cylindrical cells on the surrounding areas. The present application develops the entire process of thermal safety performance of cylindrical batteries, and monitors the test data of the triggered cylindrical cells and the test data of the cylindrical cells around the triggered cylindrical cells in real time, and compares the monitored test data with the empirical data, performs correlation analysis based on the mapping relationship, and designs and modifies the battery module based on the experimental results. For example, when the monitored test data does not meet the standards compared with the empirical data, the arrangement of the cylindrical cells can be modified, a liquid cooling plate 300 can be added, thermal insulation glue can be added, or heat dissipation gaps can be added.

[0083] The battery thermal runaway analysis method of the present application can accurately analyze the dynamic evolution mode of thermal runaway, conduct real-time testing and analysis, and make real-time modifications until the modified battery module meets the standards, at which time the test can be stopped. The battery thermal runaway analysis method of the present application can simulate whether the design of the entire battery module is reasonable, so as to reduce the impact of thermal runaway of one or more cylindrical cells on the surrounding cylindrical cells, thereby reducing the safety accidents of the entire battery module.

[0084] In addition, it is worth mentioning that the thermal runaway analysis methods in the prior art require the disassembly of the cylindrical battery samples after thermal runaway. However, in the disassembly and analysis process, interference factors are inevitably introduced, that is, the overall structure of the battery module is destroyed, resulting in misleading and interference with the true cause analysis, which is neither scientific nor precise. At the same time, due to the drastic changes in the physical and chemical forms of cylindrical batteries, the above disassembly and analysis methods are complex, have insufficient detection capabilities, and are not accurate, resulting in various problems in the cylindrical battery fault diagnosis process, resulting in a large amount of personnel costs, time costs, and equipment investment.

[0085] The battery thermal runaway analysis method of the present application can perform real-time testing and analysis based on the monitored test data, and can be modified in real time. There is no need to disassemble and analyze the cylindrical battery cell samples after thermal runaway as in the prior art, so that the overall structure of the battery module will not be damaged, and the analysis and modification of the battery module will not be misled or interfered with; at the same time, it will not require a lot of work to disassemble as in the prior art.

[0086] The battery thermal runaway analysis method of this application is specifically implemented as follows:

[0087] S1, test chamber 100 size design steps:

[0088] The size of the test box 100 is designed according to the volume, model and number of the battery modules.

[0089] S2, a simulation design step of the test box 100, performing simulation transformation on the test box 100 according to the internal and external environment information of the test box 100:

[0090] According to the position of the battery module, the internal and external pressures of the test box 100, and based on empirical data, a pressure relief valve ( Figure 1 , Figure 2 and Figure 3 The pressure relief valve installation portion 103 is used to install the pressure relief valve).

[0091] Metal material is selected to make the test box 100. Because changes in the external environment and heat generated by the battery itself will cause changes in battery temperature, which will affect the performance and service life of the battery module to a certain extent.

[0092] In step S2, a battery detection system is constructed and verified by simulating the working environment inside a real cylindrical battery pack.

[0093] S3, detection equipment installation steps, install temperature sensors on multiple cylindrical cells of the battery module:

[0094] The multiple cylindrical cells 200 of the battery module are divided into multiple test areas, and temperature sensors are installed on the multiple cylindrical cells 200 in each test area. In this way, in each test area, thermal runaway is triggered on a cylindrical cell, and the test data of the currently triggered cylindrical cell and the test data of the cylindrical cells around the triggered cylindrical cell are monitored in real time, and the monitored test data are compared with the empirical data.

[0095] In step S3, dividing into multiple test areas can, on the one hand, test the thermal runaway conditions of various positions of the battery module, increase the test accuracy, and reduce randomness; on the other hand, it can avoid the failure of the test due to trigger failure when only one cylindrical battery cell is triggered for thermal runaway.

[0096] In step S3 , a pressure sensor may be further installed to detect the pressure of the cylindrical battery cell and the pressure in the test box 100 .

[0097] S4, test step, in each test area, thermal runaway is triggered on one or more cylindrical battery cells, test data of the triggered cylindrical battery cells and test data of cylindrical battery cells around the triggered cylindrical battery cells are monitored in real time, and the monitored test data are compared with the empirical data.

[0098] The empirical data in step S4 refers to data that meets the requirements of the standard.

[0099] S5, analysis and modification steps:

[0100] The battery module design is modified based on the data comparison results.

[0101] For example, when the monitored test data does not meet the standards compared with the empirical data, the arrangement of the cylindrical battery cells 200 may be modified, a liquid cooling plate 300 may be added, thermal insulation glue may be added, or heat dissipation gaps may be added.

[0102] The following will describe the process of repeated testing and repeated modification of the battery module of the present application until the battery module composite meets the requirements.

[0103] Before the battery thermal runaway test analysis, the present application concluded through simulation software and self-design that the staggered arrangement of cylindrical cells will reduce the transmission of thermal runaway. In this regard, the present application analyzed and verified the battery thermal runaway based on the staggered arrangement of cylindrical cells.

[0104] That is, after modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps;

[0105] Specifically, Figure 2 and Figure 3 As shown, the battery module after the modified design includes a plurality of cylindrical battery cells 200, and the plurality of cylindrical battery cells 200 are divided into a plurality of rows, and the plurality of cylindrical battery cells 200 in any two adjacent rows are staggered.

[0106] The staggered arrangement of multiple cylindrical battery cells 200 can, on the one hand, improve the space utilization rate in the test box 100 (under the condition of the same capacity requirement); thus, while improving the space utilization rate, the space (gap) in the test box 100 will be increased, thereby further improving the air flow and reducing the risk of thermal runaway; on the other hand, the line contact of each cylindrical battery cell 200 can also reduce the risk of thermal runaway transmission.

[0107] The design improvement of the battery module this time has been shown through test data to significantly reduce the impact on surrounding cylindrical battery cells 200 when thermal runaway is triggered on one or more cylindrical battery cells 200 .

[0108] Furthermore, before the battery thermal runaway test analysis, the present application concluded through simulation software and self-design that adding a liquid cooling plate 300 at an appropriate position would further reduce the transmission of thermal runaway (simulating a real power battery pack). In response to this, the present application once again analyzed and verified the battery thermal runaway by adding a liquid cooling plate 300 at an appropriate position.

[0109] That is, after modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps;

[0110] Specifically, if Figure 4 and Figure 5 As shown, the battery module after the modified design also includes two liquid cooling plates 300. Figure 2 and Figure 3 As shown, the multiple cylindrical cells 200 are divided into four rows, and the multiple cylindrical cells 200 in any two adjacent rows are staggered, and the multiple cylindrical cells 200 in any two rows are arranged correspondingly. A liquid cooling plate 300 is arranged between the first row of cylindrical cells 200 and the second row of cylindrical cells 200, and a liquid cooling plate 300 is arranged between the third row of cylindrical cells 200 and the fourth row of cylindrical cells 200. A water inlet is arranged at the first end of each liquid cooling plate 300, and a water outlet is arranged at the second end of each liquid cooling plate 300.

[0111] Preferably, if Figure 4 , Figure 5 and Figure 6 As shown (the water inlet pipe 301 and the water outlet pipe 302 are not shown in the figure), the modified battery module also includes a water inlet pipe 301 and a water outlet pipe 302, and the liquid cooling plate 300 is corrugated; the battery module has a width direction and a height direction, the water inlet pipe 301 is introduced into the test box 100 from the width direction, and is connected to the water inlets of the two liquid cooling plates 300, and the water outlet pipe 302 is introduced into the test box 100 from the width direction, and is connected to the water outlets of the two liquid cooling plates 300.

[0112] With such an arrangement, the two liquid cooling plates 300 can not only cool all the cylindrical battery cells 200, but each liquid cooling plate 300 also cools two rows of cylindrical battery cells 200, and each liquid cooling plate 300 is allocated one-half of the liquid cooling liquid from the water inlet pipe 301. In this way, the two liquid cooling plates 300 cool the four rows of cylindrical battery cells 200 very evenly.

[0113] It is worth mentioning here that the water inlet pipe 301 and the water outlet pipe 302 are both introduced into the test box 100 in the width direction, so that the space in the height direction of the test box 100 will not be increased. On this basis, the design improvement of the battery module this time shows through test data that when thermal runaway is triggered on one or more cylindrical battery cells 200, the impact on the surrounding cylindrical battery cells 200 can be significantly reduced.

[0114] In the embodiments of the present application, on the one hand, in order to test the thermal runaway conditions at various locations of the battery module, the test accuracy is increased and the accidental nature is reduced; on the other hand, it can avoid the failure of the test due to the failure of the trigger when only one cylindrical battery cell is triggered for thermal runaway. The present application divides the multiple cylindrical batteries 200 of the battery module into multiple test areas, and each test is conducted simultaneously in multiple test areas.

[0115] Specifically, S3, the detection equipment installation step includes:

[0116] like Figure 7 As shown, the multiple cylindrical cells 200 of the battery module are divided into multiple test areas, wherein some test areas are hexagonal, and among the multiple cylindrical cells 200 in the hexagonal test area 10, the cylindrical cell 200 in the center is a thermal runaway trigger cell; some test areas are corner areas 20 of the battery module, and among the multiple cylindrical cells 200 in the corner area 20, the cylindrical cells 200 in the corner are thermal runaway trigger cells. After the multiple test areas are divided, temperature sensors are installed on the multiple cylindrical cells 200 in each test area.

[0117] S4, test steps:

[0118] In each test area, thermal runaway is triggered on one or more cylindrical battery cells, and the test data of the triggered cylindrical battery cells and the test data of the cylindrical battery cells around the triggered cylindrical battery cells are monitored in real time, and the monitored test data are compared with the empirical data.

[0119] In this step, thermal runaway is triggered by heating, puncturing or squeezing the cylindrical battery cell with a heating sheet.

[0120] Furthermore, the present application simulates a real power battery pack, and heat-insulating glue is provided between adjacent cylindrical cells. In this regard, the present application once again analyzes and verifies the thermal runaway of the battery. That is, after modifying the design of the battery module, the detection equipment installation steps, test test steps, and analysis and modification steps are repeated.

[0121] Furthermore, the present application simulates a real power battery pack, and the modified battery module also includes an exhaust channel 500, such as Figure 4 and Figure 5 As shown, the exhaust channel 500 is arranged at the bottom of the battery module, and the exhaust channel 500 is provided with a through hole 501 for installing the cylindrical battery cell 200.

[0122] like Figure 4 and Figure 5 As shown, the fixing frame 400 is installed on the exhaust channel 500 , and the cylindrical battery cell 200 , the water outlet pipe 302 , and the water inlet pipe 301 are installed on the fixing frame 400 .

[0123] The exhaust channel 500 is arranged at the bottom of the battery module. On the one hand, the material of the cylindrical battery cell thermal runaway will not affect the passenger compartment. On the other hand, the material of the cylindrical battery cell thermal runaway is discharged to the ground. The space between the battery pack and the ground is large, which is conducive to discharge and heat dissipation. In addition, the exhaust channel 500 is arranged at the bottom of the battery module, and can share a cavity with the anti-impact cavity of the battery pack to save space.

[0124] On this basis, the design improvement of the battery module this time shows through test data that when thermal runaway is triggered on one or more cylindrical battery cells, the impact on the surrounding cylindrical battery cells can be significantly reduced.

[0125] In summary, after repeated test design modifications, the test data finally showed that when thermal runaway was triggered on one or more cylindrical cells, the monitored test data was compared with the empirical data and met the standards.

[0126] For example, Figure 7 As shown, taking the three cylindrical cells 200 in the corner area 20 as an example, the trigger module is a ternary cell, and during the thermal runaway process, Figure 8 As shown, the temperature of the triggered cylindrical battery cell 200 reaches up to 614°C, and due to the structure of the improved battery module, the maximum temperature of the surrounding cylindrical battery cells 200 is kept below 39°C. This shows that the thermal safety solution of the power battery pack is relatively ideal.

[0127] It is also worth mentioning that the battery thermal runaway analysis method also includes a secondary inspection test step after the battery module design is modified to meet the requirements:

[0128] In the secondary inspection test step, thermal runaway is continued to be triggered on one or more cylindrical battery cells. When the triggered cylindrical battery cell has thermal runaway, if the detection data of the adjacent cylindrical battery cells do not meet the requirements, it means that there is a problem with the parameters of the cylindrical battery cell itself, so the design of the parameters of the cylindrical battery cell needs to be modified.

[0129] In summary, the thermal runaway analysis method of cylindrical batteries in the present application improves the detection accuracy by designing and processing the thermal runaway detection equipment corresponding to the cylindrical battery module, simulating the internal working environment of the cylindrical battery pack, constructing and simulating the battery detection system. After weighing the volume and accuracy of the battery module, metal materials were selected to make the battery module thermal runaway detection equipment. Changes in the external environment and the heat generated by the operation of the battery will cause changes in the battery temperature, which will affect the performance and service life of the battery pack to a certain extent. Therefore, the corresponding detection equipment for the power module is constructed, and sensors are installed in the above-mentioned device to perform relevant tests. By improving the estimation accuracy of the battery's accelerated runaway state, seamless management of the entire life cycle of the cylindrical battery can be achieved. Then, the causes and mechanisms of battery aging and failure are studied, which can fundamentally guide the improvement of lithium-ion batteries.

[0130] In addition, if Figure 1 , Figure 2 and Figure 3 As shown, the test box 100 includes a lower box 101 and a cover 102, both of which are made of metal; the cover head is connected to the upper edge of the lower box 101 by bolts, and a sealing strip 104 is provided between the upper edge of the lower box 101 and the cover 102, and the bolts can pass through the sealing strip 104. Whether the sealing strip 104 is set as a thermal conductive adhesive or a thermal insulating adhesive needs to be selected according to actual needs.

[0131] Compared with the current power battery test box, the test box of the present application can be further modified according to different test requirements due to the regulatory standards of the box, so that the detection capability and accuracy of the detection device are stronger. Secondly, the design of the test box of the present application is simplified, easy to install and disassemble, easy to clean, easy to process, and low cost.

[0132] In summary, the second aspect of the present application provides a battery module, including the battery thermal runaway analysis method as described above.

[0133] From the above battery thermal runaway analysis method, it can be seen that the battery module with the following structure meets the thermal runaway requirements:

[0134] The battery module includes a plurality of cylindrical cells 200 and two liquid cooling plates 300, the plurality of cylindrical cells 200 are divided into four rows, and the plurality of cylindrical cells 200 in any two adjacent rows are staggered; a liquid cooling plate 300 is arranged between the first row of cylindrical cells 200 and the second row of cylindrical cells 200, and a liquid cooling plate 300 is arranged between the third row of cylindrical cells 200 and the fourth row of cylindrical cells 200, and a water inlet is arranged at the first end of each liquid cooling plate 300, and a water outlet is arranged at the second end of each liquid cooling plate 300; the battery module also includes a water inlet pipe 301 and a water outlet pipe 302, and the liquid cooling plate 300 is corrugated. The battery module has a width direction and a height direction, the water inlet pipe 301 is introduced into the test box 100 from the width direction, and is connected to the water inlets of the two liquid cooling plates 300, and the water outlet pipe 302 is introduced into the test box 100 from the width direction, and is connected to the water outlets of the two liquid cooling plates 300. The battery module also includes an exhaust channel 500 , which is arranged at the bottom of the battery module. The exhaust channel 500 is provided with a through hole for installing the cylindrical battery cell 200 ; the battery module also includes a thermal insulation glue, and the thermal insulation glue is provided between adjacent cylindrical battery cells 200 .

[0135] A third aspect of the present application provides a car, comprising the battery module as described above; when the battery module is installed in the car, the exhaust channel 500 of the battery module is located at the bottom of the battery module.

[0136] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed in the present application, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be covered by the protection scope of the present application.

Claims

1. A battery thermal runaway analysis method, characterized in that: include: The test box size design steps are as follows: the size of the test box is designed according to the volume of the battery module; The test box simulation design steps include: performing simulation transformation on the test box according to the internal and external environment information of the test box; Testing equipment installation steps, installing temperature sensors on multiple cylindrical cells of the battery module; The test step includes triggering thermal runaway of one or more cylindrical cells, monitoring the test data of the triggered cylindrical cells and the test data of the cylindrical cells around the triggered cylindrical cells in real time, and comparing the monitored test data with the empirical data; Analyze the modification steps and modify the design of the battery module based on the data comparison results.

2. The battery thermal runaway analysis method according to claim 1, characterized in that: The test box simulation design steps include: According to the position of the battery module and the internal and external pressures of the test box, a pressure relief valve is installed on the test box; The steps for installing the testing equipment include: Divide the multiple cylindrical cells of the battery module into multiple test areas, and install temperature sensors on the multiple cylindrical cells in each test area; The experimental test steps include: In each test area, thermal runaway is triggered for a cylindrical battery cell, and the test data of the currently triggered cylindrical battery cell and the test data of the cylindrical battery cells around the triggered cylindrical battery cell are monitored in real time, and the monitored test data is compared with the empirical data.

3. The battery thermal runaway analysis method according to claim 2, characterized in that: After modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps; The battery module after the modified design includes a plurality of cylindrical cells, the plurality of cylindrical cells are divided into a plurality of rows, and the plurality of cylindrical cells in any two adjacent rows are staggered; The steps for installing the testing equipment include: The multiple cylindrical cells of the battery module are divided into multiple test areas, some of which are hexagonal. Among the multiple cylindrical cells in the hexagonal test area, the cylindrical cell at the center is the thermal runaway triggering cell; Part of the test area is the corner area of ​​the battery module. Among the multiple cylindrical battery cells in the corner area, the cylindrical battery cells at the corner are thermal runaway triggering cells.

4. The battery thermal runaway analysis method according to claim 3, characterized in that: After modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps; The battery module after the modified design also includes two liquid cooling plates, and the multiple cylindrical cells are divided into four rows, and the multiple cylindrical cells in any two adjacent rows are staggered; A liquid cooling plate is arranged between the first row of cylindrical battery cells and the second row of cylindrical battery cells, and a liquid cooling plate is arranged between the third row of cylindrical battery cells and the fourth row of cylindrical battery cells. A water inlet is arranged at the first end of each of the liquid cooling plates, and a water outlet is arranged at the second end of each of the liquid cooling plates.

5. The battery thermal runaway analysis method according to claim 4, characterized in that: After modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps; The battery module after the modified design also includes a water inlet pipe and a water outlet pipe, and the liquid cooling plate is corrugated; The battery module has a width direction and a height direction. The water inlet pipe is introduced into the test box from the width direction and connected to the water inlets of the two liquid cooling plates. The water outlet pipe is introduced into the test box from the width direction and connected to the water outlets of the two liquid cooling plates.

6. The battery thermal runaway analysis method according to claim 4, characterized in that: After modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps; The battery module with modified design also includes an exhaust channel, which is arranged at the bottom of the battery module and is provided with a through hole for installing the cylindrical battery cell.

7. The battery thermal runaway analysis method according to claim 4, characterized in that: After modifying the design of the battery module, repeat the test equipment installation steps, experimental test steps, and analysis and modification steps; The battery module after the modified design also includes thermal insulation glue, and the thermal insulation glue is arranged between adjacent cylindrical battery cells.

8. The battery thermal runaway analysis method according to any one of claims 1 to 7, characterized in that: The test box body comprises a lower box body and a cover body, and both the lower box body and the cover body are made of metal; The cover head is connected to the upper edge of the lower box body by bolts, a sealing strip is arranged between the upper edge of the lower box body and the cover body, and the bolts can pass through the sealing strip.

9. The battery thermal runaway analysis method according to any one of claims 1 to 7, characterized in that: The experimental test steps also include: Thermal runaway is triggered by heating, puncturing or squeezing the cylindrical battery cells through a heating sheet.

10. The battery thermal runaway analysis method according to any one of claims 1 to 7, characterized in that: The battery thermal runaway analysis method also includes a secondary inspection test step after the battery module design is modified to meet the requirements: In the secondary inspection test step, thermal runaway is continued to be triggered on one or more cylindrical battery cells. When the triggered cylindrical battery cell has thermal runaway, if the detection data of the adjacent cylindrical battery cell does not meet the requirements, the parameters of the cylindrical battery cell are modified and designed.

11. A battery module, characterized in that: The method is obtained by analyzing the battery thermal runaway analysis method according to any one of claims 1 to 10.

12. The battery module according to claim 11, characterized in that: The battery module comprises a plurality of cylindrical cells and two liquid cooling plates, the plurality of cylindrical cells are divided into four rows, and the plurality of cylindrical cells in any two adjacent rows are staggered; A liquid cooling plate is provided between the first row of cylindrical cells and the second row of cylindrical cells, and a liquid cooling plate is provided between the third row of cylindrical cells and the fourth row of cylindrical cells, a water inlet is provided at the first end of each of the liquid cooling plates, and a water outlet is provided at the second end of each of the liquid cooling plates; The battery module also includes a water inlet pipe and a water outlet pipe, and the liquid cooling plate is corrugated; The battery module has a width direction and a height direction. The water inlet pipe is introduced into the test box from the width direction and connected to the water inlets of the two liquid cooling plates. The water outlet pipe is introduced into the test box from the width direction and connected to the water outlets of the two liquid cooling plates.

13. The battery module according to claim 12, characterized in that: The battery module also includes an exhaust channel, which is arranged at the bottom of the battery module, and the exhaust channel is provided with a through hole for installing the cylindrical battery cell; The battery module also includes thermal insulation glue, and thermal insulation glue is arranged between adjacent cylindrical battery cells.

14. A car, characterized in that: comprising the battery module as claimed in claim 13; When the battery module is installed in the car, the exhaust passage of the battery module is located at the bottom of the battery module.

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