Cover plate assembly and battery

Abstract

The cover plate assembly comprises a cover plate body and lower plastic cement installed below the cover plate body, the lower plastic cement comprises a body part, a first part and a second part, and the first part and the second part protrude in the direction away from the cover plate body. The first part and the second part are located at the two ends of the body part. In the thickness direction of the lower plastic, the first part is higher than the second part; along the direction parallel to the body part, the area S11 of the first part is larger than the area S12 of the second part, so that when the electrode assembly is subjected to a vibration working condition in a manufacturing process or a use process, most impact force of the electrode assembly can act on the second part with a larger overall stress area, the possibility of crushing of the electrode plate is reduced, the risk of short circuit is reduced, and the service life of the electrode plate is prolonged. And the stability and the safety of the battery are improved.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, specifically relating to a cover plate assembly and a battery. Background Technology

[0002] In the production process of existing dual-pass cells, the electrode assembly on one side along the length of the cover plate is easily damaged. Utility Model Content

[0003] Electrode components are easily damaged during battery production, transportation, and use. In view of the shortcomings of the prior art, the purpose of this invention is to provide a cover plate assembly and a battery to improve the problem of electrode component damage due to impact.

[0004] To achieve the above and other related objectives, this utility model provides a cover plate assembly, comprising:

[0005] The cover plate body and the lower plastic installed on one side of the cover plate body, the lower plastic including a body part and a first part and a second part protruding in the direction away from the cover plate body, the first part and the second part being located at both ends of the body part;

[0006] Along the thickness direction of the lower plastic, the height of the first part is higher than the height of the second part; along the direction parallel to the body part, the area S11 of the first part is greater than the area S12 of the second part.

[0007] In a specific embodiment of this utility model, the sum of the area of ​​the first part S11 and the area of ​​the second part S12 is S1, and the area of ​​the electrode assembly facing the cover plate body is S2, wherein 0.2S2≤S1≤0.5S2.

[0008] In a specific embodiment of this utility model, in the direction parallel to the main body, the ratio A of the area of ​​the first part S11 to the area of ​​the second part S12 is such that 2≤A≤5.

[0009] In one specific embodiment of this utility model, the bottom area of ​​the second part is greater than 100mm². 2 .

[0010] In a specific embodiment of this utility model, the distance between the first part and the second part is L1, and the width of the electrode tab of the electrode assembly is L2, wherein 1.1L2≤L1≤1.5L2.

[0011] In one specific embodiment of this utility model, along the thickness direction of the lower plastic, the ratio of the height of the second part to the height of the first part is B, where 1 < B ≤ 3.

[0012] In one specific embodiment of this utility model, the height of the first part is at most 8mm, and the height of the second part is at least 2mm.

[0013] In one specific embodiment of this utility model, the height difference between the first part and the second part is H, where 1mm≤H≤2mm.

[0014] In one specific embodiment of this utility model, the first part has a chamfered structure around the side facing away from the main body.

[0015] In one specific embodiment of this utility model, the side of the first part that faces away from the main body is a fully enclosed structure.

[0016] This utility model also proposes a battery, comprising:

[0017] case;

[0018] Electrode assemblies are installed inside the housing;

[0019] As described in any of the above embodiments, the cover plate assembly is welded to the housing, and the electrode post on the cover plate assembly is connected to the electrode tab of the electrode assembly.

[0020] In one specific embodiment of the present invention, along the thickness direction of the cover plate assembly, the height of the second part of the lower plastic is 1.1 to 1.3 times the distance between the base plate of the pole post and the electrode assembly.

[0021] This utility model has the following beneficial effects:

[0022] This application designs the lower plastic part to include a first part and a second part that protrude in the direction away from the cover plate body. The area of ​​the first part is larger than the area of ​​the second part, and the height of the first part is greater than the height of the second part to form a height difference. This allows the impact force to be mainly concentrated in the larger first part during the impact between the electrode assembly and the lower plastic part. When the electrode assembly is subjected to vibration during the manufacturing process or use, most of the impact force can be transferred to the second part, which has a larger overall force-bearing area. This reduces the force per unit area, thereby reducing the possibility of electrode damage, lowering the risk of short circuit, improving the stability and safety of the battery, and providing better protection for the safety of the battery in logistics and actual use. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the cover plate assembly in one embodiment of the present invention.

[0025] Figure 2 This is an isometric view of the cover plate assembly in one embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the assembly of the cover plate assembly and the electrode assembly in one embodiment of the present invention.

[0027] Figure 4 for Figure 3 Enlarged diagram of point D in the middle.

[0028] Label Explanation:

[0029] 100. Cover plate assembly; 10. Cover plate body; 20. Lower plastic; 21. Body part; 22. First part; 23. Second part; 30. Electrode assembly; 11. Electrode post; 12. Explosion-proof valve; 31. Electrode lug. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0031] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] A dual-channel battery cell is a type of battery cell with openings at both ends of its casing, formed by two cover assemblies connected to the two openings respectively. As is known from the background art, during the manufacturing and transportation of a dual-channel battery cell, the area where the electrode assembly and the cover assembly face each other along their length is easily damaged. One cover assembly of a dual-channel battery cell includes a cover body and a lower plastic component mounted on one side of the cover body. The lower plastic component includes a body portion and a first and a second protrusion located on the side of the body portion away from the cover body, with the two protrusions located at both ends of the lower plastic component along its length. The two protrusions press against the electrode assembly, preventing the electrode assembly from shaking within the casing during transportation and use. The applicant's research revealed that the two protrusions have different contact areas with the electrode assembly. Taking the area contacting the first protrusion as the first region and the area contacting the second protrusion as the second region, with the first region being larger than the second region, the electrode assembly undergoes acceleration, deceleration, and stopping processes on the logistics line. During deceleration, because the electrode assembly is not completely fixed within the assembly, inertia causes it to impact the plastic under the top cover. Furthermore, the finished electrode assembly is susceptible to vibration and impact during transportation or actual use. The force per unit area in the second region is greater than that in the first region, making the second region more prone to damage. Through further research, the applicant provides a cover assembly and battery in this application to reduce damage to the electrode assembly.

[0033] Please see Figures 1 to 4 As shown, this utility model proposes a cover plate assembly and a battery to improve the problem that electrode components are easily damaged due to impacts with the bottom of the lower plastic layer caused by inertia and vibration during battery production, transportation, and use. In this embodiment, the cover plate assembly 100 includes a cover plate body 10 and a lower plastic layer 20, which is installed on one side of the cover plate body 10. The lower plastic layer 20 includes a body portion 21, a first portion 22, and a second portion 23. The first portion 22 and the second portion 23 are located at opposite ends of the body portion 21, and the first portion 22 and the second portion 23 protrude in a direction away from the cover plate body 10. Along the thickness direction of the lower plastic layer, the height of the first portion 22 is higher than that of the second portion 23. Along the direction parallel to the body portion, the area S11 of the first portion 22 is larger than the area S12 of the second portion 23. When the electrode component is subjected to vibration during the manufacturing process or use, most of the impact force of the electrode component can be transferred to the second portion 23, which has a larger overall force-bearing area, reducing the possibility of electrode damage, reducing the risk of short circuit, and improving the stability and safety of the battery.

[0034] Please see Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, the sum of the areas of the first part S11 and the second part S12 is S1, and the area of ​​the electrode assembly 30 facing the cover plate body 10 is S2. The ratio of area S1 to area S2 is within the range of 0.2S2≤S1≤0.5S2. This ratio ensures that the total area of ​​the lower plastic 20 is large enough to fully exert its pressure-dispersing effect. In actual battery use scenarios, various external impacts are inevitable, such as bumps and vibrations during transportation and collisions that may occur during use. When area S1 is within this ratio range, the externally applied pressure can be evenly distributed over a larger area, thereby making the pressure borne by each part of the electrode assembly 30 relatively balanced, avoiding excessive pressure in local areas, and effectively protecting the internal structure and performance of the electrode assembly 30. In this embodiment, the preferred relationship between area S1 and area S2 is S1=0.35S2. In this embodiment, the processing can be achieved through mold design and injection molding process. The mold design should precisely control the area S11 of the first part 22 and the area S12 of the second part 23 and their ratio to ensure that the total area meets the requirements.

[0035] Understandably, this ratio helps maintain the integrity of the electrode assembly 30 by dispersing pressure. As the core component of the battery, the electrode assembly's internal electrode and electrolyte structures are extremely precise and fragile. Excessive local pressure can lead to electrode deformation, electrolyte leakage, and other problems, affecting the battery's charge / discharge performance, shortening battery life, and even causing safety accidents. A reasonable total area of ​​the lower plastic layer can reduce this risk and ensure the electrode assembly operates stably in various complex environments. If S1 is less than 0.2S2, the total area is too small, and its ability to disperse pressure is significantly reduced. When subjected to external impact, the lower plastic layer 20 cannot effectively disperse the pressure, causing pressure to concentrate in a localized area of ​​the electrode assembly 30. Excessive local pressure will cause the corresponding parts of the electrode assembly 30 to bear enormous stress, easily leading to impact damage, such as electrode breakage or separator damage, seriously affecting battery performance and safety. When S1 is greater than 0.5S2, the total area is too large, which will bring a series of new problems, the most significant of which is potential interference with the explosion-proof valve position. The explosion-proof valve is a crucial safety device for batteries. Its function is to open promptly when the internal pressure of the battery is too high, releasing pressure and preventing serious accidents such as battery explosion. If the area of ​​the lower plastic piece 20 is too large, it may cover or squeeze the explosion-proof valve during installation or use, affecting its normal opening and closing. If the explosion-proof valve malfunctions, it will be unable to release pressure in time when abnormal pressure rises inside the battery, thus increasing the risk of battery explosion or fire and seriously affecting battery safety performance. Furthermore, an excessively large lower plastic piece 20 will increase the overall weight and volume of the battery, reducing its energy density and portability. In this embodiment, the ratio of area S1 to area S2 is set to 0.2S2≤S1≤0.5S2. This not only effectively disperses pressure and protects the electrode components from damage but also avoids interference with the explosion-proof valve position, ensuring battery safety performance.

[0036] Please see Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, the ratio A of the area S11 of the first part 22 to the area S12 of the second part 23 is between 2 and 5. By optimizing the force distribution, it is ensured that the first part 22 bears more force, while the second part 23 also has sufficient area to disperse the pressure, thus improving the overall stability. It is understood that the first part 22 is usually located in a more critical stress-bearing position in the entire structure. When the ratio A is between 2 and 5, the first part 22 has a relatively large area. Under the same pressure, the larger area will result in a relatively smaller pressure on the first part 22, allowing it to bear more force without generating excessive pressure, thus avoiding structural damage caused by excessive local pressure. Simultaneously, it also ensures that the area S12 of the second part 23 meets the requirement of dispersing pressure. This allows the entire structure to evenly distribute pressure among its parts when subjected to external forces, reducing stress concentration and thus improving overall stability. In this embodiment, the area ratio A is preferably 4. When A equals 4, the mechanical properties of the first part 22 and the second part 23 can be well matched. The first part 22 bears more force while its stress distribution is more uniform, which can give full play to the mechanical properties of the material. The second part 23 also has enough area to disperse the pressure and avoid the problem of stress concentration. This balance and reasonable distribution of force enables the entire structure to remain stable when subjected to force, reducing the risk of damage caused by uneven local force.

[0037] Please see Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, the area S12 of the second portion 23 is greater than 100 mm². 2 Since the area S11 of the first part 22 is larger than the area S12 of the second part 23, the area S11 of the second part 22 must be at least 200 mm. 2 This ensures that the battery has a sufficient surface area to withstand the impact, effectively reducing local pressure when the electrode assembly 30 impacts it, preventing pressure concentration from damaging the electrode assembly, and thus improving the safety and stability of the battery during production, transportation and use.

[0038] Please see Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, the distance L1 between the first part 22 and the second part 23, and the width L2 of the tab of the electrode assembly 30, wherein 1.1L2≤L1≤1.5L2, ensures that the spacing of the lower plastic 20 matches the width of the tab, preventing interference between the electrode assembly and the cover plate during movement and improving the stability of the electrode assembly. If the distance L1 between the first part 22 and the second part 23 is too small, the tab will interfere with the cover plate when the electrode assembly moves. This interference will not only affect the normal movement and positioning of the electrode assembly, but may also cause the tab to bend, deform, or even break, thereby affecting the electrical performance and safety of the battery. For example, during the battery assembly process, when the electrode assembly is accurately placed in the designated position of the lower plastic 20, if L1 is too small, the tab may be squeezed by the first part 22 and / or the second part 23 when entering the space, causing damage to the tab. When 1.1L2≤L1, the tab has enough space to pass through, avoiding interference with the cover plate and ensuring the smoothness and accuracy of the electrode assembly movement. Within this range, the tabs can be placed relatively stably in this space, without the electrode assembly shaking due to excessive spacing or being squeezed due to insufficient spacing. Stable electrode assemblies help maintain the integrity of the battery's internal structure and reduce safety hazards such as internal short circuits caused by structural instability.

[0039] It is also understandable that the area of ​​the first part 22 and the second part 23 can be increased to the maximum extent possible within this spacing range, so that when the battery is subjected to external impact, the lower plastic 20 can disperse the impact force to a larger area and effectively reduce local pressure.

[0040] Please see Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, along the thickness direction of the lower plastic 20, the height ratio of the second part 23 to the height of the first part 22 is B, where 1 < B ≤ 3. If the height difference is large, the electrode assembly will shift to the shorter side. If the height difference is small, the small area of ​​lower plastic will directly impact the electrode assembly, causing damage to the stacked body.

[0041] Specifically, when the height difference is large, i.e., the ratio B is greater than 3, under the influence of gravity and other external forces, the electrode assembly 30 will shift to the shorter side (part 22). This shift may cause changes in the relative position of the electrode assembly with other internal components of the battery, affecting the battery's electrical connection performance. For example, the tabs may be twisted or stretched due to the shift of the electrode assembly, thereby increasing resistance, reducing the battery's charging and discharging efficiency, and even potentially causing localized overheating, posing a safety hazard. Furthermore, the shifted electrode assembly is more likely to collide with other components when the battery is subjected to vibration or impact, further damaging the battery's internal structure and shortening its lifespan.

[0042] When the height difference is small, i.e., the ratio B is close to or equal to 1, the small plastic area (part 23) will directly bear a larger impact force at the moment the battery is impacted. Due to its relatively small area, under the same impact force, the pressure borne by part 23 will be relatively large. This larger pressure will be directly transmitted to the electrode assembly, impacting it. The electrode assembly is usually composed of multiple layers of laminated sheets, which are relatively fragile and easily damaged by a large impact. For example, the separator between the laminated sheets may be ruptured, leading to a short circuit between the positive and negative electrodes, causing serious safety accidents such as battery fires and explosions. In addition, damage to the laminated sheets can also lead to problems such as decreased battery capacity and unstable performance, affecting the normal use of the battery.

[0043] When the ratio B satisfies 1 < B ≤ 3, the height difference between the first part 22 and the second part 23 is within a reasonable range. At this point, the electrode assembly receives relatively balanced support, reducing the possibility of lateral displacement and ensuring its positional stability within the battery. Simultaneously, upon impact, the lower plastic layer distributes the impact force relatively evenly across the electrode assembly, preventing excessive localized impact from the second part 23. This effectively protects the stacked body, reduces the risk of battery damage, and improves battery safety and reliability.

[0044] Please see Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, the maximum height of the first part 22 is 8mm, and the minimum height of the second part 21 is 2mm. If the height is too high, from a space utilization perspective, it will occupy a large amount of internal battery space. The internal space of a battery is already limited, requiring a reasonable layout of key components such as electrode assemblies and electrolytes to achieve efficient electrochemical conversion. Excessive space occupied by these two parts will compress the usable space of the electrode assemblies, thus limiting the battery capacity. From a weight perspective, increasing the height will increase the weight of the cover plate. In today's trend towards high energy density batteries, increased battery weight means more energy is needed to drive the battery itself, which significantly reduces the battery's energy density. Conversely, if the height is too low, its protection and support for internal battery components will be weakened, failing to provide sufficient support and cushioning for components such as electrode assemblies. Electrode assemblies will be easily damaged by external pressure, thus affecting the battery's safety and stability. Furthermore, an excessively low height may not meet the insulation and sealing requirements of the battery's internal structure.

[0045] Please see Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, the height difference between the first part 22 and the second part 23 along the thickness direction of the lower plastic is H, where 1mm ≤ H ≤ 2mm. When the height difference H is between 1mm and 2mm, the second part 23, with its smaller area and lower height, can avoid direct force during mechanical conduction. Energy will preferentially be conducted and dispersed along the first part 22, which has a higher height and larger area. This effectively prevents the electrode assembly from deforming or being damaged due to excessive impact, thereby ensuring the normal operation and lifespan of the battery. Furthermore, a reasonable height difference ensures that the various battery components maintain good balance and alignment during assembly. When the height difference is within this range, a stable support structure is formed between the first part 22 and the second part 23, preventing significant tilting of the battery during assembly. This not only improves assembly efficiency and accuracy, reducing assembly errors and defect rates caused by tilting, but also ensures close cooperation and stable connection between the various components inside the battery. A stable assembly structure helps improve the overall performance and reliability of the battery. This height difference design ensures that the electrode components are not damaged in impact environments, while also ensuring the smooth assembly of the battery and a stable structure, providing a solid guarantee for the battery's high performance and high safety.

[0046] Please see Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, the first part 22 and the second part 2 are of equal height and have a height of 7.5mm as a comparative example. The actual measurements are compared with those of Embodiment 1, Embodiment 2 and Embodiment 3. The comparison results are shown in the table below.

[0047] Table 1 Comparison of Actual Measurements

[0048]

[0049] The above comparison clearly shows that both designs with unequal heights on both sides effectively prevent electrode plate damage. Different height settings may be suitable for different types and characteristics of electrode assemblies. In practical applications, the most suitable lower plastic protrusion height difference design can be selected based on the specific shape, material, and assembly process of the electrode assembly to achieve optimal protection and improve battery production quality and safety.

[0050] Please see Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, a chamfered structure is provided around the side of the first part 22 facing away from the main body 21 to prevent damage to the electrode assembly due to excessive force when the first part 22 impacts the electrode assembly 30, thereby improving the impact resistance of the electrode assembly. The radius of the chamfered structure is designed to be 0.5mm to 1mm to ensure stress dispersion without affecting structural strength.

[0051] Please see Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, the side of the first part 22 facing away from the main body 21 is a fully enclosed structure, which improves the structural strength and rigidity of the first part 22 and avoids the appearance of protrusions or grooves, which would reduce the force-bearing area during impact. This ensures that it has a sufficiently large force-bearing area during impact, which can effectively reduce local pressure when the electrode assembly 23 impacts it, and avoid pressure concentration that could damage the electrode assembly, thereby improving the safety and stability of the battery during production, transportation and use. In some embodiments, the first part 22 has a plurality of hole structures on the side opposite to the body part 21. These hole structures correspond to the explosion-proof valve 12 of the cover plate and are used to release pressure when the battery experiences thermal runaway. At this time, the thickness of this surface can be increased to ensure that the first part 22 is more robust and can withstand greater forces, thereby improving the stability of the electrode assembly. At the same time, the thickening process can ensure the rigidity of the first part 22 and prevent protrusions or grooves from reducing the force-bearing area during impact. This ensures that it has a sufficiently large force-bearing area during impact, which can effectively reduce local pressure when the electrode assembly 30 impacts it, and prevent pressure concentration from damaging the electrode assembly. This improves the safety and stability of the battery during production, transportation and use.

[0052] Please see Figures 1 to 4 As shown, this utility model also proposes a battery, which includes a casing, an electrode assembly 30, and a cover plate assembly 10 as described above. The electrode assembly 30 is installed inside the casing, the cover plate assembly 10 is welded to the casing, and the terminal post 11 on the cover plate assembly is connected to the electrode tab of the electrode assembly 30. By integrating the cover plate assembly into the battery, the overall performance and safety of the battery are improved, and the stability of the electrode assembly during logistics and use is ensured.

[0053] Please see Figures 1 to 4As shown, in this embodiment, along the thickness direction of the cover plate assembly 10, the height of the second part 23 of the lower plastic 20 is designed to be 1.1 to 1.3 times the distance between the base plate of the electrode post 11 and the electrode assembly. If the height of the second part 23 is too large, it will encroach on the space that could be used to house the electrode assembly, resulting in the electrode assembly volume not reaching its optimal level, thereby reducing the energy density of the battery. When the height of the second part 23 is too small, redundancy will occur at the tab bend, which will affect the connection stability between the tab and other components, increase contact resistance, cause the battery to generate more heat during charging and discharging, reduce battery efficiency, and may also cause the tab to break due to vibration, friction and other factors during long-term use, leading to battery failure or even safety accidents.

[0054] This utility model proposes a cover plate assembly and a battery. By designing the lower plastic part to include a first part and a second part that protrude in the direction opposite to the cover plate body, the area of ​​the first part is larger than the area of ​​the second part, and the height of the first part is greater than the height of the second part to form a height difference. This allows the impact force to be mainly concentrated in the larger first part during the impact between the electrode assembly and the lower plastic part. When the electrode assembly is subjected to vibration during the manufacturing process or use, most of the impact force can be transferred to the second part, which has a larger overall force-bearing area, reducing the force per unit area. This reduces the possibility of electrode damage, lowers the risk of short circuit, improves the stability and safety of the battery, and provides better protection for the safety of the battery in logistics and actual use.

[0055] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

[0056] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this utility model, the other technical features will not be described in detail here.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate body and the lower plastic installed on one side of the cover plate body, the lower plastic including a body part and a first part and a second part protruding in the direction away from the cover plate body, the first part and the second part being located at both ends of the body part; Along the thickness direction of the lower plastic, the height of the first part is higher than the height of the second part; Along a direction parallel to the main body, the area of ​​the first portion S11 is greater than the area of ​​the second portion S12.

2. The cover plate assembly according to claim 1, characterized in that, The sum of the area of ​​the first part S11 and the area of ​​the second part S12 is S1, and the area of ​​the electrode assembly facing the cover plate body is S2, wherein 0.2S2≤S1≤0.5S2.

3. The cover plate assembly according to claim 1, characterized in that, The ratio A of the area of ​​the first part S11 to the area of ​​the second part S12 in a direction parallel to the main body is such that 2 ≤ A ≤ 5.

4. The cover plate assembly according to claim 3, characterized in that, The area of ​​the second part, S12, is greater than 100 mm. 2 .

5. The cover plate assembly according to claim 1, characterized in that, The distance between the first part and the second part is L1, and the tab width of the electrode assembly is L2, wherein 1.1L2≤L1≤1.5L2.

6. The cover plate assembly according to claim 1, characterized in that, Along the thickness direction of the lower plastic, the ratio of the height of the second part to the height of the first part is B, where 1 < B ≤ 3.

7. The cover plate assembly according to claim 6, characterized in that, The first part has a maximum height of 8mm, and the second part has a minimum height of 2mm.

8. The cover plate assembly according to claim 7, characterized in that, The height difference between the first part and the second part is H, where 1mm≤H≤2mm.

9. The cover plate assembly according to claim 1, characterized in that, The first part has a chamfered structure on all four sides of the side facing away from the main body.

10. The cover plate assembly according to claim 1, characterized in that, The side of the first part that faces away from the main body is a fully enclosed structure.

11. A battery, characterized in that, include: case; Electrode assemblies are installed inside the housing; The cover plate assembly as claimed in any one of claims 1 to 10, wherein the cover plate assembly is welded to the housing, and the electrode post on the cover plate assembly is connected to the electrode tab of the electrode assembly.

12. The battery according to claim 11, characterized in that, Along the thickness direction of the cover plate assembly, the height of the second portion of the lower plastic is 1.1 to 1.3 times the height between the base plate of the pole post and the electrode assembly.

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