Battery module with constant battery cell pre-tightening force

Abstract

The utility model relates to the technical field of batteries, and discloses a battery module with constant battery cell pretightening force, which comprises a bottom plate and two end plates, the two end plates are perpendicular to the bottom plate and are arranged at two ends of the bottom plate, the end plates comprise a first end plate and a second end plate, the second end plate is fixedly connected with the bottom plate, and the bottom plate is fixedly connected with the bottom plate. The first end plate can move relative to the second end plate; and the constant force device is connected with the end plates, and the constant force device provides restoring force for the first end plate to move towards the second end plate. The constant force device provided by the utility model provides a pre-tightening force which is more favorable for the use of the battery cell, and the deformation of the expansion shell during the charging and discharging of the battery cell is controlled, so that the stability of the battery cell is improved, and the service life of the battery cell is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a battery module with a constant pre-tightening force for battery cells. Background Art

[0002] With the rapid development of the new energy industry, lithium battery energy storage is also developing rapidly. However, during the charging / discharging process of lithium batteries, gas may be generated inside the battery cells, and due to the generated gas, the expansion phenomenon of the battery cells expanding or contracting may occur repeatedly. In particular, there is a problem that as the battery cells are repeatedly charged / discharged, the thickness of the battery cells increases, and the housing of the battery module is deformed.

[0003] To solve the above problems, the prior art basically uses a clockwork constant force spring to connect the upper and lower covers of the module, and relies on the clockwork constant force spring to provide tension to maintain a constant force state between the battery cells. However, there are some problems: First, the constant force device using the clockwork constant force spring will not cause the load to increase linearly with the increase of displacement. This means that during the operation of the battery module, the load cannot be effectively adjusted and cannot autonomously adapt to the changing needs under different working conditions, which will lead to excessive or insufficient compression force, thus affecting the performance and life of the battery module. Second, the design of the clockwork constant force spring is complex, the manufacturing cost is high, and it is easily affected by the external environment, such as temperature change, mechanical fatigue, etc. This may cause the spring to deform or be damaged, thereby affecting the working effect of the entire battery module. Third, the space occupied by the clockwork constant force spring device in the module is relatively large, which becomes an obstacle to the improvement of the module capacity.

[0004] Therefore, it is necessary to provide a new type of battery module with a constant pre-tightening force for battery cells to solve the above problems. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a battery module with a constant pre-tightening force for battery cells, aiming to solve the technical problem that the battery cells expand and contract during the charging and discharging process, resulting in the deformation of the housing and thus affecting the service life of the battery cells.

[0006] To achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A battery module with a constant pre-tightening force for battery cells, comprising

[0008] a bottom plate and two end plates. The two end plates are perpendicularly arranged at both ends of the bottom plate. The end plates include a first end plate and a second end plate. The second end plate is fixedly connected to the bottom plate, and the first end plate is movable relative to the second end plate;

[0009] A constant force device, which is connected to the end plate and provides a restoring force for the first end plate to move towards the second end plate.

[0010] Further, the constant force device includes a metal strip assembly after heat treatment, the metal strip assembly is connected to the two end plates, and the battery cell is arranged between the first end plate and the second end plate.

[0011] Further, the constant force device includes a cable tie and an elastic member, and the elastic member is fixedly connected to the first end plate;

[0012] The first end plate and the second end plate are connected by the cable tie, and the two ends of the cable tie are connected. The cable tie provides a restoring force for the first end plate to move towards the second end plate through the elastic member.

[0013] Further, it further includes multiple groups of partition plates, and multiple groups of the partition plates are arranged between the battery cells.

[0014] Further, multiple air ducts are arranged in the partition plate, and the two ends of the air duct are communicated with each other for ventilation and heat dissipation of the battery cell.

[0015] Further, the module further includes a top plate, the top plate is connected to the two end plates, and the top plate is arranged opposite to the bottom plate.

[0016] Further, the metal strip assembly includes a first metal strip, a second metal strip and a third metal strip, wherein the first metal strip is arranged on the side far from the bottom plate, and the second metal strip and the third metal strip are respectively arranged on the two sides adjacent to and close to the bottom plate of the first metal strip.

[0017] Further, the first end plate is provided with a fixing groove, and the elastic member is arranged in the fixing groove.

[0018] Further, it further includes a baffle, and the baffle is arranged between the first end plate and the battery cell.

[0019] Further, multiple groups of the elastic members are included, and multiple groups of the elastic members are respectively arranged in multiple fixing grooves.

[0020] Beneficial effects:

[0021] In the technology of the present utility model, the constant force device connects the first end plate and the second end plate through a pre-tightening force and provides a certain restoring force, so that the battery cell maintains a constant pre-tightening force, ensuring that it will not loosen or be interfered by external forces during the working process. At the same time, the use of the elastic member and the cable tie can provide a more adjustable pre-tightening force to adapt to the needs of different battery cells. Providing the pre-tightening force is more beneficial to the use of the battery cell, and controls the deformation of the bulged shell during the charging and discharging of the battery cell, thereby improving the stability and service life of the battery cell. Description of the Drawings

[0022] Figure 1 FIG. 1 is a schematic structural diagram of an embodiment of a battery module with a constant pre-tightening force for the battery cells of the present utility model;

[0023] Figure 2 FIG. 2 is a schematic diagram of a metal strip of an embodiment of a battery module with a constant pre-tightening force for the battery cells of the present utility model;

[0024] Figure 3 FIG. 3 is a schematic structural diagram of another embodiment in the figure of a battery module with a constant pre-tightening force for the battery cells of the present utility model;

[0025] Figure 4 FIG. 4 is a schematic structural diagram of a cable tie of an embodiment in the figure of a battery module with a constant pre-tightening force for the battery cells of the present utility model;

[0026] Figure 5 FIG. 5 is a schematic structural diagram of a partition of an embodiment of a battery module with a constant pre-tightening force for the battery cells of the present utility model;

[0027] Figure 6 FIG. 6 is a schematic structural diagram of a top plate of an embodiment of a battery module with a constant pre-tightening force for the battery cells of the present utility model.

[0028] Wherein: 1, battery cell; 2, bottom plate; 31, first end plate; 32, second end plate; 41, first metal strip; 42, second metal strip; 43, third metal strip; 5, cable tie; 6, elastic member; 7, partition; 71, air duct; 8, fixing groove; 9, baffle; 10, top plate.

[0029] The realization, functional features and advantages of the object of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiments

[0030] It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0031] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, 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 of the said features. In the description of the present utility model, "a plurality" means two or more unless otherwise specifically and clearly defined.

[0032] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0034] Refer to Figures 1 to 6, the present utility model provides a battery module with a constant pre-tightening force for the battery cell 1, comprising: a bottom plate 2 and two end plates, the two end plates are perpendicularly arranged at both ends of the bottom plate 2, the end plates include a first end plate 31 and a second end plate 32, the second end plate 32 is fixedly connected to the bottom plate 2, and the first end plate 31 is movable relative to the second end plate 32; a constant force device, the constant force device is connected to the end plates, and the constant force device provides a restoring force for the first end plate 31 to move towards the second end plate 32.

[0035] In the above embodiment, the bottom plate 2 connects the two end plates, and the two end plates are connected to form a stable module structure. At the same time, the first end plate 31 is movable through the constant force device. This connection method can flexibly adjust the distance between the two end plates as needed. The constant force device is connected to the end plates to ensure that the first end plate 31 has a restoring force to move towards the second end plate 32. This connection method can not only improve the structural stability of the module, but also provide a certain elasticity to adapt to different usage requirements; through the restoring force provided by the constant force device, the first end plate 31 can always apply a certain pressure to the second end plate 32, so as to keep the pre-tightening force of the battery cell 1 stable, which helps to ensure that the battery cell 1 does not loosen during use, and improves the reliability and safety of the battery module; since the connection distance between the first end plate 31 and the second end plate 32 can be adjusted, the distance between the two end plates can be adjusted according to needs. This flexibility makes the battery module applicable to battery cells 1 of different specifications, and also facilitates the installation and maintenance of the module; the connection between the bottom plate 2 and the two end plates forms a stable module structure, which can effectively support and protect the battery cell 1. This structural stability helps to prevent the battery cell 1 from being damaged during transportation or use, and extends the service life of the battery module; the restoring force provided by the constant force device has a certain elasticity, which can adapt to the expansion and contraction of the battery cell 1 during use. This elastic adaptability helps to reduce the stress concentration between the battery cell 1 and the module, and improves the stability and durability of the module; providing a pre-tightening force is more beneficial to the use of the battery cell 1, and controls the deformation of the bulged shell of the battery cell 1 during charging and discharging, thereby improving the stability and life of the battery cell 1. Using the natural cooling in the energy storage usage scenario reduces the cost.

[0036] In one embodiment, the constant force device includes a metal bar assembly after heat treatment, the metal bar assembly is connected to the two end plates, and the battery cell 1 is arranged between the first end plate 31 and the second end plate 32.

[0037] In the above embodiments, the constant force device includes a metal strip assembly after heat treatment. The metal strip assembly is connected to two end plates, and the metal strip assembly is in an arcuate shape. After heat treatment, the metal strip has a certain strength and elasticity. It is connected to the two end plates, and by connecting with the end plates, it provides a restoring force for the movement of the first end plate 31 towards the second end plate 32; the metal strip assembly has an arcuate design, which enables it to form a spring-like structure and is stronger than a spring. When the first end plate 31 moves away from the second end plate 32, the metal strip assembly will be stretched and store elastic energy. When the external force decreases or disappears, the metal strip assembly will release the stored elastic energy, causing the first end plate 31 to return to its original position; the metal strip assembly has a constant elasticity and can provide a relatively constant pre-tightening force within a certain range. This helps to maintain a constant contact pressure between the battery cells 1, prevent them from loosening or falling off. At the same time, the constant pre-tightening force can also ensure the normal operation of the battery cells 1 and extend their service life; the arcuate design of the metal strip assembly gives it a large deformation range and elasticity, enabling it to adapt to the expansion and contraction of the battery cells 1 during use. This design helps to reduce the impact of external forces on the battery cells 1 and stress concentration, improving the reliability and durability of the module; the connection between the metal strip assembly and the two end plates is relatively simple, easy to manufacture and install. This simple connection method can reduce production costs and improve production efficiency; the design of the metal strip assembly can be adjusted as needed. By changing the material, size or shape of the metal strip assembly, the magnitude and range of the pre-tightening force can be adjusted to meet the requirements of different application scenarios.

[0038] In one embodiment, the constant force device includes a cable tie 5 and an elastic member 6. The elastic member 6 is fixedly connected to the first end plate 31; the first end plate 31 and the second end plate 32 are connected by the cable tie 5, and the two ends of the cable tie 5 are connected to each other. The cable tie 5 provides a restoring force for the movement of the first end plate 31 towards the second end plate 32 through the elastic member 6.

[0039] In the above embodiments, a combined connection method using a cable tie 5 and an elastic member 6 is adopted. Specifically, the first end plate 31 and the second end plate 32 are connected by the cable tie 5, and the two ends of the cable tie 5 are connected to form a closed loop. At the same time, the elastic member 6 is fixedly connected to the first end plate 31, and by being connected to the cable tie 5, it realizes the restoring force for the first end plate 31 to move towards the second end plate 32; the cable tie 5, as a connecting element, has the characteristics of being simple, easy to use, and flexible. It can firmly fix the battery cell 1 and the end plate, and form a stable connection with the bottom plate 2, thereby ensuring the stability and reliability of the device; the elastic member 6 supplies the restoring force for the first end plate 31 to move towards the second end plate 32 by being connected to the cable tie 5, and its restoring force can be adjusted as needed. By selecting different materials or adjusting parameters such as the size and shape of the elastic member 6, different restoring forces can be adjusted to meet the requirements in different application scenarios; at the same time, if it is necessary to replace or adjust the constant force device, only need to untie the cable tie 5 and replace the elastic member 6, which is convenient and fast.

[0040] In one embodiment, it further includes multiple groups of partition plates 7, and multiple groups of the partition plates 7 are arranged between the battery cells 1 and the battery cells 1.

[0041] In the above embodiments, multiple groups of partition plates 7 are used as elements for connecting between the battery cells 1. Multiple groups of partition plates 7 are arranged between the battery cells 1 to play a role of fixing and isolating. The specific connection method can use methods such as screws, nuts, welding, and bonding to connect the partition plates 7 and the battery cells 1 together, ensuring close contact between the partition plates 7 and the battery cells 1, and ensuring the firmness and reliability of the connection; the main function of the partition plates 7 is to isolate and protect between the battery cells 1. In some application scenarios, a certain isolation distance needs to be maintained between the battery cells 1 to prevent safety problems such as short circuits and current leakage. The arrangement of multiple groups of partition plates 7 can effectively isolate each battery cell 1, thereby improving the safety and stability of the entire system; by arranging multiple groups of partition plates 7 between the battery cells 1, the structural stability of the entire system can be increased. The presence of the partition plates 7 can prevent the relative displacement of the battery cells 1 during use, and reduce damage or loosening caused by external forces, vibrations and other factors, which helps to extend the service life of the device and reduce the frequency of maintaining and replacing the end plates; the arrangement of multiple groups of partition plates 7 can also provide optimization of thermal management. When the battery cells 1 are working, heat will be generated. If there are no effective heat dissipation measures, it may cause the temperature of the battery cells 1 to rise, thereby affecting performance and life. By arranging partition plates 7 between the battery cells 1, heat dissipation channels can be increased, promoting heat conduction and dissipation, and improving the thermal management ability of the entire system to ensure that the battery cells 1 work within an appropriate temperature range.

[0042] In one embodiment, a plurality of air ducts 71 are arranged in the partition plate 7, and both ends of the air ducts 71 are communicated with each other for ventilation and heat dissipation of the battery cell 1.

[0043] In the above embodiments, multiple sets of partition plates 7 are used as elements for connecting the battery cells 1. A plurality of air ducts 71 are provided inside the partition plates 7, and both ends of these air ducts 71 are communicated, realizing the fixation and ventilation and heat dissipation between the battery cells 1, effectively increasing the contact area between the surface of the battery cells 1 and the external environment, which is beneficial to heat dissipation. When the battery cells 1 are working, a large amount of heat will be generated. If it cannot be dissipated in time, it may cause the temperature of the battery cells 1 to rise, thereby affecting the performance and lifespan. By providing the air ducts 71 inside the partition plates 7, more heat dissipation channels can be provided, promoting the conduction and dissipation of heat, thereby improving the heat dissipation effect of the entire system; the arrangement of the plurality of air ducts 71 can optimize the ventilation performance. The presence of the air ducts 71 can improve the air circulation inside the battery cells 1 and accelerate the discharge of hot air. By making both ends of the air ducts 71 communicate, the air flow between the battery cells 1 can be realized, effectively eliminating or reducing the formation of hot spots and improving the ventilation effect. This optimization of the ventilation performance helps to reduce the temperature of the battery cells 1 and improve the stability and reliability of the system; the arrangement of multiple air ducts 71 inside the partition plates 7 also helps to enhance the safety of the system. When the battery cells 1 are working, due to the concentrated heat generation, if the heat dissipation is not smooth, it may cause the battery cells 1 to overheat or even cause safety problems such as fires. By providing the air ducts 71, the heat dissipation channels can be effectively increased, promoting the conduction and dissipation of heat, and taking away the heat in time to avoid the occurrence of safety hazards.

[0044] In one embodiment, the module further includes a top plate 10, the top plate 10 is connected to the two end plates, and the top plate 10 is disposed opposite to the bottom plate 2.

[0045] In this embodiment, the top plate 10 is disposed opposite to the bottom plate 2 to ensure the close contact between the top plate 10 and the end plates, and to ensure the firmness and reliability of the connection; by connecting the top plate 10 to the two end plates and disposing the top plate 10 opposite to the bottom plate 2, a stable module structure can be formed, increasing the stiffness and stability of the entire module, enabling it to withstand external pressure and weight. Whether during transportation or use, the module can remain stable, preventing damage or deformation caused by external factors; adopting the connection method of the top plate 10 and the end plates makes the disassembly of the module more convenient. When it is necessary to repair, clean or replace components of the module, only the screws or nuts connecting the top plate 10 and the end plates need to be loosened to disassemble the module, without the need for destructive disassembly of the entire structure, which can save time and effort and improve the maintenance efficiency.

[0046] In one embodiment, the metal strip assembly includes a first metal strip 41, a second metal strip 42 and a third metal strip 43, wherein the first metal strip 41 is disposed on the side away from the bottom plate 2, and the second metal strip 42 and the third metal strip 43 are respectively disposed on the two sides adjacent to and close to the bottom plate 2 of the first metal strip 41.

[0047] In this embodiment, it includes a metal strip assembly including a first metal strip 41, a second metal strip 42, and a third metal strip 43. Among them, the first metal strip 41 is disposed on the side away from the bottom plate 2, that is, the top plate side, while the second metal strip 42 and the third metal strip 43 are respectively disposed on both sides adjacent to and close to the bottom plate 2 of the first metal strip 41. By using the metal strip assembly and connecting it to the top plate 10 and the bottom plate 2, a stable structure can be formed. The setting of the metal strip assembly can increase the overall stiffness and stability of the module, enabling it to withstand external pressure and weight. This connection method can effectively prevent the deformation or breakage of the module, ensuring its stability during battery use; by disposing the first metal strip 41 on one side of the top plate 10, and disposing the second metal strip 42 and the third metal strip 43 on both sides adjacent to and close to the bottom plate 2 of the first metal strip 41, the load of the module can be effectively dispersed and borne. This connection method can improve the overall stiffness of the module, reduce the risk of structural deformation, thereby better protecting the battery cell 1 inside the module, and the second metal strip 42 and the third metal strip 43 are disposed on both sides close to the bottom plate 2, so that the first end plate 31 will not deflect when moving.

[0048] In one embodiment, the first end plate 31 is provided with a fixing groove 8, and the elastic member 6 is disposed in the fixing groove 8.

[0049] In this embodiment, in addition to using the elastic member 6 to connect components, the first end plate 31 is provided with a fixing groove 8, and the elastic member 6 is disposed in the fixing groove 8, which can provide additional support and stability, ensuring the accuracy and durability of the connection. Even under external forces or vibrations, the elastic member 6 can be kept stable; the fixing groove 8 can adopt various shapes and materials, and the shape of the fixing groove 8 is also customized according to the specific shape and size of the elastic member 6. The fixing groove 8 can be rectangular or circular to adapt to different-shaped elastic members 6, or it can have a serrated or threaded internal structure to increase the friction with the elastic member 6, thereby preventing loosening or slipping during use. The presence of the fixing groove 8 can prevent excessive deformation of the elastic member 6. When the external force applied exceeds the range that the elastic member 6 can bear, the fixing groove 8 will play a limiting role to prevent the elastic member 6 from continuing to deform, thereby protecting the integrity and durability of the structure.

[0050] In one embodiment, it further includes a baffle 9, and the baffle 9 is disposed between the first end plate 31 and the battery cell 1.

[0051] In this embodiment, a baffle 9 is further introduced. The baffle 9 is arranged between the first end plate 31 and the battery cell 1, playing the roles of isolation, protection and support. The baffle 9 is inserted between the first end plate 31 and the battery cell 1 to ensure that there is a certain contact area between it and the two, and the baffle 9 is firmly connected to the end plate and the battery cell 1 by means such as screws, clamping, welding, etc. The selection and design of the baffle 9 need to be carried out according to the requirements of specific applications. For example, in some cases, the baffle 9 can completely conform to the shapes of the end plate and the battery cell 1 to provide the maximum contact area and support force. In other cases, the baffle 9 may need to have specific openings or holes to adapt to the installation of other components or the passage of wire harnesses. The setting of the baffle 9 can play an isolation role, separating the battery cell 1 from the end plate to avoid their direct contact or mutual interference, which is for preventing the battery cell 1 from being affected by external impacts, vibrations or abrasions, thereby prolonging the service life of the battery cell 1 and increasing the stability of the battery pack; the baffle 9 also has a protection function. It can prevent foreign substances or liquids from entering the gap between the battery cell 1 and the end plate, reducing the corrosion, pollution or damage of the external environment to the battery cell 1. The baffle 9 can also prevent the battery cell 1 from being affected by moisture, dust, chemical substances, etc., improving the reliability and safety of the overall system; the presence of the baffle 9 can provide additional support. It can strengthen the connection between the end plate and the battery cell 1, increasing the rigidity and stability of the entire structure, which is of great significance for the position fixation of the battery cell 1 and the stability of the battery pack under vibrations or impacts. The support function of the baffle 9 can effectively reduce the looseness and swing between components, improving the overall performance and reliability of the battery module.

[0052] In one embodiment, the elastic members 6 include multiple groups, and the multiple groups of elastic members are respectively arranged in multiple fixing grooves 8.

[0053] In this embodiment, the elastic members 6 are composed of multiple groups, and the multiple groups of elastic members are respectively arranged in multiple fixing grooves 8. The connection method can use methods such as screws, welding, gluing, etc. to connect the elastic members 6 with other components; arranging multiple groups of elastic members 6 in multiple fixing grooves 8 can provide sufficient elastic performance. The design and material selection of the elastic members 6 can make them have a certain compression elastic force and resilience performance. When external pressure or deformation is applied, they can quickly return to their original state, thereby realizing the buffering and protection effects on the entire structure, and can disperse and absorb forces from different directions, reducing the direct contact and collision between components, thereby reducing the risk of wear and looseness of the connecting components; the setting of multiple groups of elastic members 6 can provide a certain degree of adjustability. By adjusting the tightness of the fixing screws, the compression degree of the elastic members 6 can be changed, thereby adjusting the elasticity and stability of the entire structure. This adjustability makes this connection method applicable to different application scenarios and can meet different pressure and load requirements.

[0054] The above are only the preferred embodiments of the present utility model, and thus do not limit the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present utility model.

Claims

1. A battery module with constant cell preload, characterized in that: include: A bottom plate and two end plates, wherein the two end plates are perpendicular to the bottom plate and are arranged at two ends of the bottom plate, the end plates include a first end plate and a second end plate, the second end plate is fixedly connected to the bottom plate, and the first end plate is movable relative to the second end plate; A constant force device is connected to the end plate, and provides a restoring force for the first end plate to move toward the second end plate.

2. The battery module with constant cell preload according to claim 1, characterized in that: The constant force device comprises a heat-treated metal bar assembly, the metal bar assembly is connected to the two end plates, and the battery core is arranged between the first end plate and the second end plate.

3. The battery module with constant cell preload according to claim 1, characterized in that: The constant force device comprises a cable tie and an elastic member, and the elastic member is fixedly connected to the first end plate; The first end plate and the second end plate are connected by the cable tie, and both ends of the cable tie are connected. The cable tie provides a restoring force for the first end plate to move toward the second end plate through the elastic member.

4. The battery module with constant cell preload according to claim 1, characterized in that: It also includes a plurality of groups of partitions, wherein the plurality of groups of partitions are arranged between the battery cells.

5. The battery module with constant cell preload according to claim 4, characterized in that: A plurality of air ducts are arranged in the partition, and the two ends of the air ducts are connected to each other for ventilation and heat dissipation of the battery core.

6. The battery module with constant cell preload according to claim 1, characterized in that: The module also includes a top plate, which is connected to the two end plates and is arranged opposite to the bottom plate.

7. The battery module with constant cell preload according to claim 2, characterized in that: The metal strip assembly includes a first metal strip, a second metal strip and a third metal strip, wherein the first metal strip is arranged on a side away from the bottom plate, and the second metal strip and the third metal strip are respectively arranged on two sides adjacent to the first metal strip and close to the bottom plate.

8. The battery module with constant cell preload according to claim 3, characterized in that: The first end plate is provided with a fixing groove, and the elastic member is arranged in the fixing groove.

9. The battery module with constant cell preload according to claim 3, characterized in that: It also includes a baffle, which is arranged between the first end plate and the battery core.

10. The battery module with constant cell preload according to claim 8, characterized in that: The elastic members include a plurality of groups, and the plurality of groups of elastic members are respectively arranged in a plurality of fixing grooves.

Images