Testing device and testing method for expansion force of battery module

Abstract

The invention relates to a testing device and a testing method for expansion force of a battery module. The testing device comprises a mounting assembly, a pressure detection assembly and a battery management unit. According to the invention, the pressure detection assembly is arranged between two adjacent battery packs, and the battery management unit synchronously collects the cycle charge-discharge times and the expansion force of the battery packs, so that the dynamic correlation analysis of the charge-discharge process and the expansion force is realized. Therefore, whether the expansion force of the battery module is within the bearing range or not is determined by analyzing the relationship between the expansion force and the charging and discharging times, and the cycle life of the battery module and the damage degree of the mounting assembly are reasonably judged. Moreover, the fault trend of the battery cell can be predicted according to the dynamic correlation analysis of the charging and discharging process and the expansion force, and measures can be taken in advance for maintenance or replacement, so that the occurrence of battery faults is reduced, and the service life of the battery is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a test pile and a test method for the expansion force of a battery module. Background Art

[0002] During the production process of lithium-ion batteries, including the battery cells in a battery module, the thickness of the battery cells will change during the charge and discharge cycles. As the number of charge and discharge cycles increases, the thickness of the battery cells will gradually increase, and this expansion will not be completely pressed back when under pressure, resulting in the battery cells bulging. If the battery module is not properly designed, the expansion force generated by the battery module during long-term use will damage the module end plate, destroy the module structure, and lead to safety risks. Therefore, the test of the expansion force of the battery cells is extremely important, and it can be used as a key factor to evaluate whether the structure of the battery cells or the battery module is safe. Summary of the Invention

[0003] Embodiments of this application provide a test pile and a test method for the expansion force of a battery module to at least partially solve the above technical problems.

[0004] To achieve the above object, according to the first aspect of this application, a test device for the expansion force of a battery module is provided, including: a mounting assembly for carrying the battery module, the battery module including a plurality of battery packs and an acquisition and integration component electrically connected to the battery packs, and each battery pack including a plurality of battery cells; a pressure detection component disposed between two adjacent battery packs and capable of detecting the expansion force of the battery packs; and a battery management unit electrically connected to the acquisition and integration component and the pressure detection component respectively, the battery management unit receiving the number of charge and discharge cycles in the battery packs through the acquisition and integration component and receiving the expansion force corresponding to each charge and discharge cycle of the battery packs through the pressure detection component.

[0005] In some embodiments, the mounting assembly includes two first fixing beams disposed opposite to each other in the length direction and two second fixing beams connected between the two first fixing beams, and the four cooperate to enclose a mounting cavity, both the battery module and the pressure detection component are disposed in the mounting cavity, and the battery packs are clamped between the pressure detection component and the first fixing beams.

[0006] In some embodiments, the mounting assembly further includes: a carrying base, and both the first fixing beams and the second fixing beams are fixed on the carrying base; the test device further includes: a liquid cooling component fixedly installed on the carrying base and located between the carrying base and the battery module.

[0007] In some embodiments, the collection integrated component includes: a bus and a signal collection component, the bus is arranged on the side of the battery cell away from the supporting base, and is used to connect the poles of the battery cell; the signal collection component is arranged on the side of the battery cell away from the supporting base and is electrically connected to the bus, and is used to collect temperature information and / or voltage information of the battery cell; wherein the bus has a protrusion protruding toward the side away from the supporting base.

[0008] In some embodiments, the collection integrated component further includes: a jumper bar, which is arranged on a side of the battery cell away from the supporting base and is electrically connected to the bus bar, wherein the jumper bar and the pressure detection component are arranged opposite to each other in the vertical direction.

[0009] In some embodiments, the battery module expansion force testing device further includes: at least one insulating member disposed between the busbar and the battery cell, the insulating member having an opening for exposing the pole of the battery cell.

[0010] In some embodiments, the battery module expansion force testing device also includes: a first buffer structure, arranged between the supporting base and the first fixed beam and / or the second fixed beam; and / or a second buffer structure, arranged on the supporting base and located between the battery module and the first fixed beam and / or the second fixed beam.

[0011] In some embodiments, the pressure detection assembly includes two fixed plates arranged opposite to each other along the length direction and a pressure sensor. The pressure sensor is clamped between the two fixed plates. Each fixed plate is in contact with and fitted to at least one battery cell in the battery pack. The pressure sensor is electrically connected to the battery management unit.

[0012] In some embodiments, a positioning groove is provided on a surface of at least one fixing plate facing the other fixing plate, and the pressure sensor is disposed in the positioning groove.

[0013] In order to achieve the above object, according to a second aspect of the present application, a method for testing the expansion force of a battery module is provided, comprising:

[0014] Cyclic charge and discharge are performed on the battery pack under test, and expansion force test is performed on the battery pack under test by using a test device;

[0015] Record the number of charge and discharge cycles of the tested battery pack and the expansion force in each charge and discharge cycle;

[0016] Establish a relationship curve according to the number of charge and discharge cycles of the tested battery pack and the expansion force corresponding to each charge and discharge cycle;

[0017] The deformation amount of the battery module is determined according to the relationship curve.

[0018] The technical effect of this application is to provide a test device and a test method for the expansion force of a battery module. The pressure detection component is arranged between two adjacent battery packs, and the battery management unit synchronously collects the number of charge and discharge cycles and the expansion force of the battery packs to realize the dynamic correlation analysis of the charge and discharge process and the expansion force. Therefore, by analyzing the relationship between the expansion force and the number of charge and discharge cycles, it can be determined whether the expansion force of the battery module is within the tolerable range, and the cycle life of the battery module and the degree of damage of the installation component can be reasonably judged. Moreover, according to the dynamic correlation analysis of the charge and discharge process and the expansion force, the fault trend of the battery cell can be predicted, and measures can be taken in advance for maintenance or replacement to reduce the occurrence of battery failures, thereby improving the battery life.

[0019] Other features and advantages of this application will be described in detail in the following specific implementation section. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of this application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0021] In order to more fully understand this application and its beneficial effects, the following description will be made in conjunction with the drawings, where the same reference numerals represent the same parts in the following description.

[0022] Figure 1 is the structural schematic diagram of the test device provided in the embodiment of this application Figure 1 ;

[0023] Figure 2 is the exploded view of the test device provided in the embodiment of this application;

[0024] Figure 3 is the structural schematic diagram of the test device provided in the embodiment of this application Figure 2 ;

[0025] Figure 4 is the structural schematic diagram of the pressure detection component provided in the embodiment of this application Figure 1 ;

[0026] Figure 5 is the structural schematic diagram of the pressure detection component provided in the embodiment of this application Figure 2 。

[0027] Description of the Reference Numerals:

[0028] 100. Installation component; 101. First fixed beam; 102. Second fixed beam; 103. Installation cavity; 104. Bearing base; 200. Battery module; 201. Battery pack; 202. Acquisition integration component; 203. Jumper row; 111. Battery cell; 2021. Bus bar; 211. Protrusion; 2022. Signal acquisition component; 221. Flexible circuit board; 222. Acquisition terminal; 300. Pressure detection component; 301. Fixed plate; 302. Pressure sensor; 303. Positioning groove; 400. Battery management unit; 500. Liquid cooling component; 501. Liquid cooling plate; 502. Water inlet pipe; 503. Water outlet pipe; 600. Insulating component; 700. First buffer structure; 800. Second buffer structure. Detailed implementation manner

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0030] In the case where the structure design of the battery module is improper, the expansion force generated by the battery module will damage the module end plate, resulting in the destruction of the battery module structure and posing a safety risk. Therefore, in the design and development of the battery module, the calculation of the expansion force needs to be considered. The traditional battery module expansion force test only tests the expansion force at the battery cell level, and the module test cannot be equivalent to the battery cell in the whole package usage situation.

[0031] Therefore, the present application provides a test device and a test method for the expansion force of a battery module. The present application sets the pressure detection component between two adjacent battery packs, and synchronously collects the number of charge and discharge cycles and the expansion force of the battery pack through the battery management unit to realize the dynamic correlation analysis of the charge and discharge process and the expansion force. Therefore, by analyzing the relationship between the expansion force and the number of charge and discharge cycles, it is determined whether the expansion force of the battery module is within the tolerable range, and the cycle life of the battery module and the degree of damage to the installation component are reasonably judged. And, based on the dynamic correlation analysis of the charge and discharge process and the expansion force, the fault trend of the battery cell can be predicted, and measures can be taken in advance for maintenance or replacement to reduce the occurrence of battery failures, thereby improving the life of the battery cell.

[0032] As Figure 1 , Figure 2 and Figure 3 shown, the present application provides a test device for the expansion force of a battery module, including an installation component 100, a pressure detection component 300, and a battery management unit 400.

[0033] The mounting assembly 100 is used to carry the battery module 200. The battery module 200 includes a plurality of battery packs 201 and an acquisition and integration component 202 electrically connected to the battery packs 201. The battery pack 201 includes a plurality of battery cells 111. The pressure detection component 300 is disposed between two adjacent battery modules 200 and can detect the expansion force of the battery module 200. The battery management unit 400 is electrically connected to the acquisition and integration component 202 and the pressure detection component 300 respectively. The battery management unit 400 receives the number of charge and discharge cycles M of the battery module 200 through the acquisition and integration component 202, and receives the expansion force F corresponding to each charge and discharge cycle through the pressure detection component 300. Therefore, by detecting the magnitude of the expansion force of the battery module 200, it is determined whether the expansion force of the battery module 200 is within the tolerable range, and the cycle life of the battery module 200 and the degree of damage of the mounting assembly 100 are reasonably judged.

[0034] As Figure 1 shown, the mounting assembly 100 includes two first fixing beams 101 arranged opposite to each other in the length direction and two second fixing beams 102 connected between the two first fixing beams 101, and the four cooperate to enclose a mounting cavity 103. Both the battery module 200 and the pressure detection component 300 are disposed in the mounting cavity 103, and the battery pack 201 is clamped between the pressure detection component 300 and the first fixing beam 101.

[0035] Specifically, the mounting cavity 103 formed by the two first fixing beams 101 and the two second fixing beams 102 forms a solid frame structure. This design provides good support and stability, ensuring that the battery module 200 and the pressure detection component 300 maintain fixed positions during the test. The battery pack 201 is clamped between the pressure detection component 300 and the first fixing beam 101, enabling the pressure detection component 300 to directly sense the expansion force of the battery pack 201. This direct contact method improves the accuracy and sensitivity of pressure detection, ensuring the accuracy of the data.

[0036] As Figure 1 and Figure 2 shown, the mounting assembly 100 further includes a bearing base 104, and both the first fixing beam 101 and the second fixing beam 102 are fixed on the bearing base 104. The bearing base 104 can disperse and bear the weight and force from the battery module 200 and the pressure detection component 300, reduce the pressure on a single fixing beam, and extend the service life of the mounting assembly 100.

[0037] As Figure 1 and Figure 2As shown, the battery management unit 400, also known as the BMS (Battery Management System), is a system specifically designed to manage and monitor batteries, ensuring the safety, performance, and lifespan of the battery pack 201. The battery management unit 400 is disposed on the outer periphery of the mounting assembly 100.

[0038] As Figure 2 shown, the test device further includes a liquid cooling component 500. The liquid cooling component 500 is fixedly mounted on the carrying base 104 and is located between the carrying base 104 and the battery module 200. Therefore, by controlling the temperature of the battery module 200 through the liquid cooling component 500, the safety risks caused by overheating, such as thermal runaway or battery damage, are reduced, which helps to ensure the safety of the test process.

[0039] As Figure 2 shown, the liquid cooling component 500 includes a liquid cooling plate 501, an inlet water pipe 502 and an outlet water pipe 503 connected to the liquid cooling plate 501. The liquid cooling plate 501 is fixed on the carrying base 104. The liquid cooling plate 501 is arranged in a plate shape and can be connected by screws or blind rivets. The liquid cooling plate 501 is hollow inside. The inlet water pipe 502 is used for supplying coolant to flow into the liquid cooling plate 501. The coolant absorbs the heat of the battery pack 201 in the liquid cooling plate 501, and after absorbing the heat, it flows out from the outlet water pipe 503, taking away the heat of the battery module 200, so as to achieve the purpose of cooling the battery pack 201.

[0040] As Figure 1 and Figure 2 shown, the acquisition and integration component 202 (CCS component), as the core part of the battery safety monitoring center, plays a crucial role in the safety performance of the battery pack. Among them, the acquisition and integration component 202 includes a busbar 2021, a signal acquisition component 2022, etc. The busbar 2021 is disposed on the side of the battery cell 111 away from the carrying base 104 and is used to connect the electrode posts of the battery cell 111, providing a simplified and efficient electrical connection method, reducing the complex wiring requirements, and improving the convenience of installation and maintenance. And, the busbar 2021 can effectively transmit current, reduce the resistance loss, thereby improving the power transmission efficiency of the entire system.

[0041] As Figure 1 and Figure 2As shown, the signal acquisition component 2022 is disposed on the side of the battery cell 111 facing away from the carrier base 104 and is electrically connected to the bus bar 2021, and is used to acquire the temperature information and / or voltage information of the battery cell 111. The signal acquisition component 2022 includes components such as a flexible circuit board 221 and an acquisition terminal 222. The flexible circuit board 221 is electrically connected to the bus bar 2021 through the acquisition terminal 222, and can acquire the temperature information and / or voltage information of the battery cell 111 in real time, helping to detect abnormal conditions such as overheating or voltage imbalance, so that the monitoring system can quickly respond to changes in the state of the battery cell 111 and ensure the safety and stability of the system.

[0042] In one embodiment, as Figure 2 shown, the bus bar 2021 has a protrusion 211 protruding toward the side facing away from the carrier base 104, and the protrusion 211 can detect the deformation amount of a single battery cell 111 before and after expansion. Specifically, before the battery cell 111 expands, the first distance D1 in the Z direction between the protrusion 211 and the base is obtained; after the battery cell 111 expands, the first distance D2 in the Z direction between the protrusion 211 and the base is obtained; finally, the difference between the first distance D1 and the first distance D2 is obtained, and this difference is the deformation amount of the battery cell 111. Among them, both the first distance D1 and the first distance D2 are the maximum distances.

[0043] As Figure 1 and Figure 2 shown, the acquisition and integration component 202 further includes a jumper 203. The jumper 203 is disposed on the side of the battery cell 111 away from the carrier base 104 and is electrically connected to the bus bar 2021. Among them, the jumper 203 and the pressure detection component 300 are arranged opposite to each other in the vertical direction. It can be understood that the electrical connection between the jumper 203 and the bus bar 2021 provides an efficient current transmission path, further simplifies the electrical connection layout, helps to reduce resistance loss, and improves the power transmission efficiency. The relative arrangement of the jumper 203 and the pressure detection component 300 in the vertical direction ensures that while the electrical connection is made, the pressure can be effectively monitored, which helps to monitor the physical state of the battery cell 111 in real time and ensure that it is within a safe operating range.

[0044] As Figure 2As shown, the test device for the expansion force of the battery module further includes at least one insulating member 600, and at least one insulating member 600 is disposed between the bus bar 2021 and the battery cell 111. The insulating member 600 can prevent accidental metal contact or other conductive material contact with the pole of the battery cell 111, thereby avoiding potential short - circuit or electric shock risks. Moreover, the insulating member 600 not only provides electrical isolation but also can serve as a physical support layer to help fix the bus bar 2021 and the battery cell 111, increasing the structural stability of the entire assembly. The insulating member 600 is provided with an opening for exposing the pole of the battery cell 111 to achieve precise electrical connection between the bus bar 2021 and the pole while maintaining insulation for other parts.

[0045] In one embodiment, as Figure 2 shown, the test device for the expansion force of the battery module further includes a first buffer structure 700. The first buffer structure 700 is disposed between the bearing base 104 and the first fixing beam 101 in the vertical direction. Alternatively, the first buffer structure 700 is disposed between the bearing base 104 and the second fixing beam 102. Alternatively, the first buffer structure 700 is disposed between the bearing base 104 and the first fixing beam 101 and between the bearing base 104 and the second fixing beam 102. This can effectively absorb and relieve the expansion force generated by the battery cell 111 during charge and discharge, and helps protect the battery cell 111 and related components from mechanical stress damage.

[0046] In one embodiment, as Figure 2 shown, the test device for the expansion force of the battery module further includes a second buffer structure 800. The second buffer structure 800 is disposed on the bearing base 104 and is located between the battery module 200 and the first fixing beam 101. Alternatively, the second buffer structure 800 is disposed on the bearing base 104 and is located between the battery module 200 and the second fixing beam 102. Alternatively, the second buffer structure 800 is disposed on the bearing base 104 and is located between the battery module 200 and the first fixing beam 101 and between the battery module 200 and the second fixing beam 102, which helps to more effectively absorb and disperse the expansion force of the battery module, further reducing the mechanical stress on the test device.

[0047] In one embodiment, as Figure 2 shown, the test device for the expansion force of the battery module can include both the first buffer structure 700 and the second buffer structure 800 at the same time. Through the combined action of the first buffer structure 700 and the second buffer structure 800, double - buffer protection is provided.

[0048] In one embodiment, as Figure 4 and Figure 5As shown, the pressure detection component 300 includes two fixing plates 301 arranged opposite to each other along the length direction and a pressure sensor 302, and the pressure sensor 302 is clamped between the two fixing plates 301. The two fixing plates 301 provide a uniform contact surface, ensuring that the pressure sensor 302 can uniformly sense the pressure change on the surface of the battery cell 111, which helps to improve the accuracy of pressure measurement.

[0049] As Figure 2 and Figure 4 shown, each fixing plate 301 is in contact with and attached to at least one battery cell 111 in the battery pack 201, and the pressure sensor 302 is electrically connected to the battery management unit 400. Through the attachment of the fixing plate 301 to the battery cell 111, the pressure sensor 302 can directly sense the expansion force or pressure change of the battery cell 111 and provide accurate pressure data. The electrical connection between the pressure sensor 302 and the battery management unit 400 enables real-time data transmission, and the battery management system can immediately obtain the pressure state of the battery cell 111. Therefore, the pressure sensor 302 can detect the expansion force or pressure change of the battery cell 111 in real time and transmit the data to the battery management unit 400. This real-time monitoring helps to promptly identify abnormal situations, such as excessive expansion or too high pressure.

[0050] At least one side surface of one fixing plate 301 facing the other fixing plate 301 is provided with a positioning groove 303, and the pressure sensor 302 is arranged in the positioning groove 303. The positioning groove 303 can position the pressure sensor 302 in all directions, ensuring the accurate position of the pressure sensor 302 on the fixing plate 301 and preventing the sensor from shifting or deviating during use, thereby improving the measurement accuracy. Figure 4 and Figure 5 schematically show that each fixing plate 301 is provided with a positioning groove 303, providing double stability and support to ensure the precise positioning of the pressure sensor 302 in all directions.

[0051] The first test method for the deformation amount of the battery pack 201 is: calculating the total sum of the deformation amounts of each battery cell 111 in the battery pack 201 before and after expansion.

[0052] The second test method for the deformation amount of the battery pack 201 is: selecting the average value of the deformation amounts of some (more than two) battery cells 111 in the battery pack 201, and then multiplying this average value by the number of battery cells 111 in the battery pack 201, and the deformation amount of the battery pack 201 can be obtained.

[0053] The third method for testing the deformation amount of the battery pack 201 is as follows: Before the battery pack 201 expands, record the gap L1 between every two adjacent battery cells 111, the gap L2 between the battery cell 111 closest to the first fixed beam 101 and the first fixed beam 101, and the gap L3 between the battery cell 111 closest to the second fixed beam 102 and the second fixed beam 102; after the battery pack 201 expands, record the gap L4 between every two adjacent battery cells 111, the gap L5 between the battery cell 111 closest to the first fixed beam 101 and the first fixed beam 101, and the gap L6 between the battery cell 111 closest to the second fixed beam 102 and the second fixed beam 102; finally, obtain the difference between L1 and L4, the difference between L2 and L5, and the difference between L3 and L6, and reflect the deformation amount of the battery pack 201 through at least one of these differences.

[0054] Therefore, the influence of the cyclic test of the whole pack on the module structural parts can be simulated by recording the deformation amount of the battery pack 201.

[0055] The embodiment of the present application further provides a method for testing the expansion force of a battery module, including:

[0056] Perform cyclic charge and discharge on the battery pack 201 to be tested, and use a test device to perform an expansion force test on the battery pack 201 to be tested;

[0057] Record the number of cyclic charge and discharge times of the battery pack 201 to be tested and the expansion force in each charge and discharge cycle;

[0058] Establish a relationship curve according to the number of cyclic charge and discharge times of the battery pack 201 to be tested and the expansion force corresponding to each cyclic charge and discharge;

[0059] Determine the deformation amount of the battery module 200 according to the relationship curve.

[0060] The steps of performing cyclic charge and discharge on at least one battery cell 111 in the battery pack 201 to be tested and using a test device to perform an expansion force test on the battery cell 111 include: at a preset temperature, charge and discharge each battery cell 111 in the battery pack 201 to be tested with a constant current, and use the aforementioned test device to monitor the expansion force of the battery pack 201. Using the test device to perform an expansion force test can ensure the accuracy and reliability of the data. The test device can accurately measure the magnitude of the expansion force and record the relevant data of each cycle, providing a reliable basis for subsequent data analysis and processing.

[0061] The steps of recording the number of charge-discharge cycles of the battery pack 201 under test and the swelling force in each charge-discharge cycle include: performing multiple charge-discharge cycles on the battery cells 111 in the battery pack 201, and recording the number of charge-discharge cycles of each battery cell 111 and the swelling force in each charge-discharge cycle; or, performing multiple charge-discharge cycles on the battery cells 111 in the battery pack 201, and recording the number of charge-discharge cycles of some (more than two) battery cells 111 and the swelling force in each charge-discharge cycle. Therefore, this step performs multiple charge-discharge cycles on the battery cells 111 to simulate their service life in actual use, and records the change of the swelling force in each cycle to evaluate the long-term stability and durability of the battery cells 111.

[0062] This test method can record information such as the maximum value and average value of the swelling force, providing key data for evaluating the swelling degree of the battery cells 111 at different cycle stages. Establishing a relationship curve based on the number of charge-discharge cycles and the swelling force can intuitively reflect the correlation between the two. By analyzing parameters such as the slope and intercept of the curve, a battery health state evaluation model can be established to predict the remaining service life of the battery. When the change of the swelling force is abnormal, such as a sudden increase in the slope of the curve, it indicates that the battery cells 111 may have internal short circuits, lithium plating and other faults, and early warnings can be given in time to avoid further deterioration of the battery performance and even safety accidents. In addition, determining the deformation amount of the battery module 200 according to the relationship curve can real-time master the volume change of the battery during the charge-discharge process. If the deformation amount is too large, it may cause deformation of the installation component 100, damage to the internal structure, and even safety problems such as thermal runaway. By monitoring the deformation amount, measures can be taken in time to ensure the safety of battery use.

[0063] The above test method can test at least one battery cell 111 in the battery pack 201 under test, reducing the test workload and cost. At the same time, through the detailed test of a single battery cell 111, the performance change of the battery cell 111 can be more accurately understood, avoiding test errors caused by the mutual influence of multiple battery cells 111.

[0064] In the description of this application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined.

[0065] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0066] Among the embodiments, implementation manners and related technical features of this application, they can be combined and replaced with each other without conflict.

[0067] The above are only the preferred embodiments of the present application, and do not impose any formal restrictions on the present application. However, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A battery module expansion force testing device, characterized in that: include: A mounting assembly for carrying a battery module, wherein the battery module includes a plurality of battery packs and a collection integrated component electrically connected to the battery packs, and the battery pack includes a plurality of battery cells; A pressure detection component, disposed between two adjacent battery packs, capable of detecting the expansion force of the battery packs; A battery management unit is electrically connected to the acquisition integrated component and the pressure detection component, respectively. The battery management unit receives the number of charge and discharge cycles in the battery pack through the acquisition integrated component, and receives the expansion force corresponding to each charge and discharge cycle of the battery pack through the pressure detection component.

2. The battery module expansion force testing device according to claim 1, characterized in that: The mounting assembly includes two first fixed beams arranged opposite to each other along the length direction and two second fixed beams connected between the two first fixed beams, and the four cooperate to form a mounting cavity. The battery module and the pressure detection assembly are both arranged in the mounting cavity, and the battery pack is clamped between the pressure detection assembly and the first fixed beams.

3. The battery module expansion force testing device according to claim 2, characterized in that: The mounting assembly further includes: a load-bearing base, on which the first fixed beam and the second fixed beam are both fixed; The testing device further includes: a liquid cooling assembly fixedly mounted on the supporting base and located between the supporting base and the battery module.

4. The battery module expansion force testing device according to claim 3, characterized in that: The acquisition integrated component includes: a busbar and a signal acquisition component, wherein the busbar is arranged on a side of the battery cell away from the supporting base and is used to connect the pole of the battery cell; the signal acquisition component is arranged on a side of the battery cell away from the supporting base and is electrically connected to the busbar; Wherein, the bus bar has a protrusion protruding toward a side away from the supporting base.

5. The battery module expansion force testing device according to claim 4, characterized in that: The collection integrated component also includes: a jumper bar, which is arranged on a side of the battery cell away from the supporting base and is electrically connected to the bus bar, wherein the jumper bar and the pressure detection component are arranged opposite to each other in the vertical direction.

6. The battery module expansion force testing device according to claim 4, characterized in that: Also includes: At least one insulating member is disposed between the busbar and the battery cell, and the insulating member is provided with an opening for exposing the pole of the battery cell.

7. The battery module expansion force testing device according to claim 3, characterized in that: Also includes: A first buffer structure is arranged between the bearing base and the first fixed beam and / or the second fixed beam; and / or The second buffer structure is arranged on the supporting base and is located between the battery module and the first fixing beam and / or the second fixing beam.

8. The battery module expansion force testing device according to claim 1, characterized in that: The pressure detection assembly includes two fixing plates arranged opposite to each other along the length direction and a pressure sensor. The pressure sensor is clamped between the two fixing plates. Each fixing plate is in contact with and fitted to at least one battery cell in the battery pack. The pressure sensor is electrically connected to the battery management unit.

9. The battery module expansion force testing device according to claim 8, characterized in that: A positioning groove is provided on a surface of at least one of the fixing plates facing the other fixing plate, and the pressure sensor is arranged in the positioning groove.

10. A method for testing the expansion force of a battery module, characterized in that: include: Cyclic charge and discharge are performed on the battery pack under test, and expansion force test is performed on the battery pack under test by using a test device; Record the number of charge and discharge cycles of the tested battery pack and the expansion force in each charge and discharge cycle; Establish a relationship curve according to the number of charge and discharge cycles of the tested battery pack and the expansion force corresponding to each charge and discharge cycle; The deformation amount of the battery module is determined according to the relationship curve.

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