Cover plate assembly and battery

Abstract

The present application relates to the technical field of batteries. Disclosed are a cover plate assembly and a battery. The cover plate assembly comprises: a cover plate; a support member, which is arranged on one side of the cover plate and is provided, on the side of the support member away from the cover plate, with a first boss and a second boss spaced apart in the direction of length of the support member, the first boss and the second boss protruding in a direction away from the cover plate, a recess being formed between the first boss and the second boss, and the recess being adapted to accommodate a tab arranged on an electrode assembly; and a protective plate, which is arranged on the side of the support member away from the cover plate and comprises a base plate and a support rib, wherein the side of the base plate close to the support member is fixedly connected to the support rib, the base plate abuts against the bosses arranged on the support member, the other side of the base plate away from the support rib is a flat surface, a clearance groove is formed in the base plate and configured for the tab to pass therethrough, the clearance groove is spaced apart from the support rib, and the support rib is located in the recess and abuts against the bottom surface of the recess. The flat surface of the protective plate comes into contact with the electrode assembly, thereby improving the uniformity of stress distribution of the electrode assembly.

Description

Cover assembly and battery

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410970680.3, filed on July 19, 2024, entitled “Cover Assembly and Battery”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, specifically to cover plate assemblies and batteries. Background Technology

[0004] Lithium-ion batteries typically consist of components such as a casing, electrode assembly, cover plate, and support components. The cover plate and casing are fixed together by laser welding, providing a sufficiently strong, sealed protective space for mounting the electrode assembly. The support component, located between the cover plate and the electrode assembly, serves as insulation and protection. A recess is formed on the side of the support component facing the electrode assembly to provide space for the electrode tabs to bend. The portion outside the recess forms a boss that abuts against the electrode assembly to support it and prevent it from shifting.

[0005] Because the cover plate integrates multiple functions such as explosion-proof valves, terminals, electrolyte filling holes, and temperature sensing zones, space design is often very tight. With the increasing demands on the overcurrent of battery structural components, it is necessary to maximize the width of the tabs to meet overcurrent requirements. To make reasonable use of the space on the cover plate, the terminals on the cover plate are usually designed off-center. Therefore, the tabs on the electrode assembly usually need to be designed off-center. Correspondingly, the off-center design of the recess on the support component results in the two protrusions on both sides of the recess being of different sizes. The contact area between the smaller protrusion and the electrode assembly is much smaller than that between the larger protrusion and the electrode assembly. After battery assembly, the forces on both sides of the electrode assembly corresponding to the two protrusions are uneven. The smaller protrusion exerts higher pressure on the electrode assembly, which can easily lead to overpressure on the electrode assembly on the side corresponding to the smaller protrusion. The proportion of electrode assembly damaged by pressure is very high, affecting the battery assembly yield. Summary of the Invention

[0006] In view of this, this application provides a cover plate assembly and a battery to solve the problem of uneven force distribution on the electrode assembly.

[0007] In a first aspect, this application provides a cover plate assembly, comprising: a cover plate; a support member disposed on one side of the cover plate, wherein the support member has a first protrusion and a second protrusion spaced apart along the length direction of the support member on the side away from the cover plate, the first protrusion and the second protrusion protruding in a direction away from the cover plate, and a recessed portion formed between the first protrusion and the second protrusion, the recessed portion being adapted to accommodate an electrode tab on an electrode assembly; and a protective plate disposed on the side of the support member away from the cover plate, the protective plate comprising a base plate and a support rib, wherein the support rib is fixedly connected to the side of the base plate near the support member, the base plate abutting against the protrusion on the support member, the other side of the base plate away from the support rib being planar, and a clearance groove is formed on the base plate for the electrode tab to pass through, the clearance groove being spaced apart from the support rib, and the support rib being located within the recessed portion and abutting against the bottom surface of the recessed portion.

[0008] Beneficial effects: By adding a protective plate to the side of the support member away from the cover plate, a protective plate is added between the support member and the electrode assembly when the cover plate assembly is installed in the battery. The flat side of the protective plate's base plate contacts the electrode assembly, meaning the protective plate abuts against the electrode assembly through its flat surface. Compared to the traditional method where the electrode assembly only contacts the cover plate through protrusions on the support member, this increases the contact area between the cover plate assembly and the electrode assembly. This avoids uneven force distribution at both ends of the electrode assembly along its length due to unequal sizes of the first and second protrusions on the support member. Therefore, when the cover plate assembly presses down on the electrode assembly, it improves the uniformity of force distribution on the electrode assembly, prevents localized overpressure, and enhances the pressure balance at both ends of the electrode assembly along its length, preventing... The concentrated stress on the electrode assembly reduces the risk of damage from crushing and improves battery assembly yield. Furthermore, by setting support ribs on the protection plate, the structural strength of the protection plate is increased. The support ribs are located in the recess between the first and second protrusions on the support member. The support ribs support the substrate and the support member, preventing the corresponding part of the substrate and the recess from bending and deforming towards the support member, which would cause separation from the electrode assembly. This further improves the uniformity of stress on the electrode assembly. At the same time, by opening clearance grooves on the substrate, clearance space is provided for the tabs on the electrode assembly, ensuring that the tabs can pass smoothly through the protection plate and enter the recess of the support member, so as to facilitate the connection between the tabs and the terminal posts on the cover plate.

[0009] In one alternative embodiment, the clearance groove opens toward one side of the substrate.

[0010] Beneficial effects: By opening the clearance groove on one side of the substrate, it is easier to process and shape the clearance groove, and it is also easier to assemble with the electrode tab. At the same time, it also provides more design space for the support rib, which helps to improve the structural strength of the support rib, thereby improving the reliability of the protection plate.

[0011] In one optional embodiment, the dimension W1 of the clearance groove along the width direction of the protective plate ranges from 2.3mm to 3.5mm.

[0012] Beneficial effects: By setting the dimension W1 of the clearance groove in the width direction to be within the range of 2.3mm-3.5mm, sufficient clearance space can be reserved for the electrode tab to prevent damage to the electrode tab, uneven stress on the electrode group can be avoided, and the structural strength of the protection plate can be guaranteed.

[0013] In one optional embodiment, the ratio between the dimension W1 of the clearance groove along the width direction of the protective plate and the thickness H0 of the tab is in the range of 2.3 ≤ W1 / H0 ≤ 11.7.

[0014] Beneficial effects: By setting the ratio of the width W1 of the clearance groove to the thickness H0 of the electrode lug within the range of 2.3-11.7, it can ensure that the clearance groove provides sufficient clearance space for the bending of the electrode lug, prevent interference between the protective plate and the electrode lug, thereby avoiding damage to the electrode lug, and also ensure that the protective plate has sufficient structural strength and avoid uneven stress on the electrode assembly.

[0015] In one optional embodiment, the clearance groove has a dimension of L1 along the length of the protective plate, and the tab has a dimension of L2 along the length of the protective plate, wherein L1 is greater than L2, and the difference between L1 and L2 is 6mm-8mm; and / or, the thickness H1 of the substrate is in the range of 0.8mm-1.2mm.

[0016] Beneficial effects: By setting the dimension L1 of the clearance groove along its length to be larger than the dimension L2 of the tab along its length, and the increase of L1 over L2 being within the range of 6mm-8mm, it is possible to ensure that the clearance groove provides sufficient space for the tab, preventing damage to the tab, and also to improve the uniformity of stress on the tab. By setting the thickness H1 of the substrate within the range of 0.8mm-1.2mm, it is possible to ensure that the substrate can be formed smoothly and has sufficient structural strength, ensuring the uniformity of stress on the electrode assembly, and also to avoid the protection board occupying too much internal space of the battery and damaging the electrode assembly, and to avoid the energy density of the battery being affected by the excessive weight of the protection board.

[0017] In one optional embodiment, the height H2 of the support rib is in the range of 2.5mm-3mm; and / or, the dimension W2 of the support rib along the width direction of the protective plate is in the range of 3mm-5mm; and / or, the distance W3 between the support rib and the clearance groove is in the range of 1.5mm-2.5mm.

[0018] Beneficial effects: By setting the height H2 of the support rib within the range of 2.5mm-3mm, the support rib can ensure stable support between the substrate and the support component, improving the stability of the protective plate and preventing localized damage to the electrode assembly and corresponding bosses due to poor contact between the middle section of the protective plate and the electrode assembly. It also prevents excessive compression of the support rib from damaging the electrode tab. By setting the width W2 of the support rib within the range of 3mm-5mm, sufficient support strength and adequate width of the clearance groove are ensured, thus preventing damage to the electrode tab. By setting the distance W3 between the support rib and the clearance groove within the range of 1.5mm-2.5mm, sufficient space is provided for bending of the electrode tab, ensuring adequate clearance and preventing damage. This also ensures sufficient support strength of the support rib, improving structural stability.

[0019] In one optional embodiment, a buckle is provided on the side of the substrate facing the support member, and a corresponding slot is provided on the side of the support member facing the protective plate, wherein the buckle engages with the slot.

[0020] Beneficial effects: By setting buckles on the substrate and corresponding slots on the protective plate, the substrate and the protective plate can be assembled through the cooperation of the buckles and slots. The buckle and slot structure is simple, easy to form, and the cooperation method is firm and reliable. The cooperation process is easy to operate, which helps to improve the stability of the protective plate and the support after assembly and improves the assembly efficiency.

[0021] In one alternative embodiment, the buckle includes two latching portions spaced apart from each other, each latching portion including a connecting segment and a hook, the connecting segment connecting the base plate and the hook, and each hook bending away from the other hook.

[0022] Beneficial effects: By setting the buckle to include two spaced-apart snap-fit ​​parts, with the hooks on the two snap-fit ​​parts extending in opposite directions, when the buckle is inserted into the slot, the side wall of the slot squeezes the hooks, the connecting section undergoes slight elastic deformation, and the tops of the two snap-fit ​​parts move closer to each other to facilitate the hooks entering the slot. After the hooks enter the slot, the connecting section springs back, realizing the snap-fit ​​between the buckle and the slot, which facilitates the buckle entering the slot and provides high stability after assembly.

[0023] In one alternative embodiment, the substrate is thermally fused to the support member.

[0024] Beneficial effects: The substrate and boss are fixed by hot pressing, eliminating the need for additional connection structures. The structure of the protective plate and support is simple, the hot-melt process is easy to operate, and the cost is low.

[0025] Secondly, this application also provides a battery, comprising: a housing having an open end; an electrode assembly disposed within the housing, the electrode assembly having tabs; and the aforementioned cover assembly, the cover assembly being disposed at the open end of the housing, a support member and a protective plate being located within the housing, and the cover being welded to the housing to seal the housing. Since the battery includes the cover assembly and has the same effect as the cover assembly, it will not be described in detail here. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 is an exploded view of the positive electrode side of a traditional battery;

[0028] Figure 2 is an exploded schematic diagram of the negative electrode side of a traditional battery;

[0029] Figure 3 is a structural schematic diagram of a support member according to an embodiment of this application;

[0030] Figure 4 is a schematic diagram of the structure of a protective plate according to an embodiment of this application;

[0031] Figure 5 is a magnified view of part A in Figure 4;

[0032] Figure 6 is a schematic diagram of another protective plate according to an embodiment of this application;

[0033] Figure 7 is a schematic diagram of the positional relationship between the protective plate and the support member before assembly according to an embodiment of this application;

[0034] Figure 8 is a schematic diagram of the structure after the protective plate and support are assembled according to another embodiment of this application;

[0035] Figure 9 is a schematic diagram of the structure of a support member, a protective plate and an electrode tab after assembly according to an embodiment of this application;

[0036] Figure 10 is a schematic diagram of the structure of a battery according to an embodiment of this application;

[0037] Figure 11 is a front view of the battery shown in Figure 10;

[0038] Figure 12 is a left view of the battery shown in Figure 10;

[0039] Figure 13 is a cross-sectional view along the BB direction in Figure 12.

[0040] Explanation of reference numerals in the attached drawings: 1. Cover plate; 101. Pole post; 102. Cover plate protective patch; 2. Support member; 220. End plate; 201. First boss; 202. Second boss; 203. Recess; 204. Slot; 3. Protective plate; 301. Base plate; 302. Support rib; 303. Clearance groove; 304. Buckle; 305. Snap-fit ​​part; 315. Connecting section; 325. Hook; 335. Guide surface; 4. Pole group; 401. Pole tab; 5. Housing; 501. Blue film; 6. Side plate; 7. Bare cell insulating sheet. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] As shown in Figures 1 and 2, a battery typically consists of a casing 5, electrode assembly 4, blue film 501, cover plate 1 (integrating terminal posts 101, explosion-proof valve, electrolyte filling hole, etc.), support components, cover plate protective patch 102, side plate 6, bare cell insulating sheet 7, electrolyte, etc. The blue film 501 and cover plate protective patch 102 are mainly applied to the outer surfaces of the casing 5 and cover plate 1, providing mechanical protection and insulation. The side plate 6 and bare cell insulating sheet 7 mainly cover the outside of the electrode assembly 4, protecting it from external damage and providing insulation. The support components mainly provide space for electrode tab bending, insulation protection, support for the electrode assembly 4, and prevent electrode assembly 4 from shifting. The cover plate 1 and casing 5 are fixed by laser welding, providing a sufficiently strong sealed protective space for the electrode assembly.

[0043] Because the cover plate 1 integrates multiple functions such as explosion-proof valve, terminal post 101, liquid injection hole, and temperature sensing area, the space design is often very tight. In addition, with the continuous increase in the demand for fast charging of batteries, the requirements for overcurrent of structural components are constantly increasing. It is necessary to maximize the cross-sectional area of ​​the tab 401 to meet the overcurrent requirements. In order to make reasonable use of the space on the cover plate, the tab 401 needs to be eccentrically designed. The first protrusion 201 on the support is larger than the second protrusion 202. Therefore, the contact surface between the second protrusion 202 and the electrode group 4 is much smaller than the contact surface between the first protrusion 201 and the electrode group 4. This results in uneven force on both sides of the electrode group 4 when the cover plate assembly is inserted into the shell, resulting in overpressure on the side of the electrode group 4 corresponding to the second protrusion 202. The proportion of electrode group 4 damaged by pressure is very high, which affects the cell assembly yield.

[0044] The embodiments of this application are described below with reference to Figures 3 to 13.

[0045] According to an embodiment of this application, in one aspect, a cover plate assembly is provided, as shown in Figures 1 to 9. The cover plate assembly includes: a cover plate 1, a support member 2, and a protective plate 3. The support member 2 is disposed on one side of the cover plate 1. The side of the support member 2 away from the cover plate 1 has a first protrusion 201 and a second protrusion 202 spaced apart along the length direction of the support member 2. The first protrusion 201 and the second protrusion 202 protrude in a direction away from the cover plate 1, and a recess 203 is formed between the first protrusion 201 and the second protrusion 202. The recess 203 is adapted to accommodate the electrode tabs 401 on the electrode assembly 4. The protective plate 3 is disposed on the side of the support member 2 away from the cover plate 1, protecting... The plate 3 includes a base plate 301 and a support rib 302. The support rib 302 is fixedly connected to the side of the base plate 301 near the support member 2. The base plate 301 abuts against the boss on the support member 2. The other side of the base plate 301 away from the support rib 302 is flat. A clearance groove 303 is provided on the base plate 301 for the tab 401 to pass through. The clearance groove 303 and the support rib 302 are spaced apart. The support rib 302 is located in the recess 203 and abuts against the bottom surface of the recess 203.

[0046] It should be noted that the length direction refers to the "length direction" indicated by the arrow in Figure 3; the bosses on the support member 2 refer to the first boss 201 and the second boss 202; the bottom surface of the recess 203 refers to the surface of the support member 2 located in the area of ​​the recess 203 facing the protective plate 3; the tab 401 passes through the relief groove 303 and then bends into the recess 203. The bent tab 401 is used for electrical connection with the pole post 101 on the cover plate 1. The bent tab 401 is located between the support rib 302 and the bottom surface of the recess 203. The support rib 302 presses the tab 401 onto the support member 2, that is, the support rib 302 indirectly abuts against the support member 2 through the tab 401; since the tab 401 has solder marks, the support rib 302 abuts against the solder marks of the tab 401 and will not damage the tab 401.

[0047] In this embodiment, the cover plate assembly adds a protective plate 3 to the side of the support member 2 away from the cover plate 1. When the cover plate assembly is installed in the battery, the protective plate 3 is added between the support member 2 and the electrode group 4. The flat side of the substrate 301 of the protective plate 3 contacts the electrode group 4, that is, the protective plate 3 abuts against the electrode group 4 through the flat side. Compared with the traditional form where the electrode group 4 is only contacted by the boss on the support member 2, the contact area between the cover plate assembly and the electrode group 4 is increased. This avoids uneven force on both ends of the electrode group 4 along the length direction due to the unequal size of the first boss 201 and the second boss 202 on the support member 2. Therefore, when the cover plate assembly presses the electrode group 4, the uniformity of the force on the electrode group 4 is improved, local overpressure on the electrode group 4 is avoided, the pressure balance at both ends of the electrode group 4 along the length direction is improved, and damage due to local force concentration on the electrode group 4 is prevented. This reduces the risk of the electrode assembly being damaged by pressure and improves the battery assembly yield. Furthermore, by providing support ribs 302 on the protection plate 3, the structural strength of the protection plate 3 is increased. The support ribs 302 are located in the recess 203 between the first boss 201 and the second boss 202 on the support member 2. The support ribs 302 are supported between the substrate 301 and the support member 2, preventing the corresponding part of the substrate 301 and the recess 203 from bending and deforming towards the support member 2, which would cause separation from the electrode assembly 4, and further improves the uniformity of the force on the electrode assembly 4. At the same time, by opening a clearance groove 303 on the substrate 301, clearance space is provided for the tabs 401 on the electrode assembly 4, ensuring that the tabs 401 can pass smoothly through the protection plate 3 and enter the recess 203 of the support member 2, so as to facilitate the connection between the tabs 401 and the pole post 101 on the cover plate 1.

[0048] Specifically, the protective plate 3 is made of insulating material, serving as an insulating and protective element. Optionally, the protective plate 3 is made of PP (polypropylene), which has good insulation properties.

[0049] Optionally, the support rib 302 is integrally formed with the substrate 301, the support rib 302 protrudes from the surface of the substrate 301, and the support rib 302 is a long strip extending along the length direction of the protective plate 3.

[0050] Optionally, the support member 2 is the lower plastic on the negative electrode side of the battery. Further referring to Figure 2, the lower plastic on the negative electrode side is assembled with the cover plate 1. The lower plastic has a first boss 201, a second boss 202, and a recess 203. The second boss 202 is smaller than the first boss 201. Correspondingly, the tab 401 is the negative electrode tab. It can be understood that, as an alternative implementation, the support member 2 can also be the end plate 220 on the positive electrode side of the battery. Further referring to Figure 1, the lower plastic on the positive electrode side is directly connected to the cover plate 1 without any bosses. The end plate 220 is located between the cover plate 1 and the electrode group 4. The end plate 220 has a first boss 201, a second boss 202, and a recess 203 on the side facing the electrode group. Correspondingly, the tab 401 is the positive electrode tab.

[0051] In one embodiment, the clearance groove 303 opens on one side facing the substrate 301. By opening the clearance groove 303 on one side of the substrate 301, it facilitates the processing and forming of the clearance groove 303, and also facilitates the assembly with the tab 401. At the same time, it also provides more design space for the support rib 302, which helps to improve the structural strength of the support rib 302, thereby improving the reliability of the protective plate 3. Further referring to Figures 4 and 6, the clearance groove 303 penetrates the substrate 301 along the thickness direction of the protective plate 3. The clearance groove 303 is provided on one edge of the substrate 301 along the width direction. The tab 401 bends at the clearance groove 303. After passing through the clearance groove 303 and around the protective plate 3, the tab 401 enters the recess 203 of the support member 2 for further welding with the pole post 101 on the cover plate 1. Here, the width direction refers to the "width direction" indicated by the arrow in Figures 4 and 6; the thickness direction refers to the "thickness direction" indicated by the arrow in Figures 4 and 6.

[0052] In one embodiment, further referring to Figure 4, the dimension W1 of the clearance groove 303 along the width direction of the protective plate 3 ranges from 2.3mm to 3.5mm. It should be noted that the dimension W1 of the clearance groove 303 along the width direction of the protective plate 3 is the width of the clearance groove 303. The clearance groove 303 provides clearance for the tab 401. If the width W1 of the clearance groove 303 is less than 2.3mm, the dimension of the clearance groove 303 along the width direction is too small, providing insufficient space for the tab 401 to bend and turn, which is not conducive to the passage of the tab 401 and may easily cause damage to the bending point of the tab 401, thus affecting the battery performance. If the width W1 of the clearance groove 303 is greater than 3.5mm, the dimension of the clearance groove 303 along the width direction is too large, and the width of the solid portion on the substrate 301 corresponding to the clearance groove 303 along the width direction is too small, affecting the substrate... The weakening of the strength of 301 affects the structural strength and makes it easier for the bend of the tab 401 to be damaged. Furthermore, the contact area between this solid part and the electrode assembly 4 is too small, causing an imbalance in the pressure on the electrode assembly along the width direction. Additionally, the design space left for the support rib 302 on the substrate 301 is too small, which is not conducive to the placement of the support rib 302 and will affect the structural strength of the protective plate 3. Therefore, by setting the clearance groove 303 with a width dimension W1 within the range of 2.3mm-3.5mm, sufficient clearance space can be reserved for the tab 401 to prevent damage to it, uneven stress on the electrode assembly 4 can be avoided, and the structural strength of the protective plate 3 can be guaranteed. Here, the width direction refers to the "width direction" indicated by the arrow in Figure 4.

[0053] In one embodiment, the ratio between the dimension W1 of the clearance groove 303 along the width direction of the protective plate 3 and the thickness H0 of the tab 401 ranges from 2.3 ≤ W1 / H0 ≤ 11.7. It should be noted that the thickness H0 of the tab 401, as shown in Figure 13, is related to the type and capacity of the battery, and varies from 0.3 to 1.0 mm depending on the battery. The larger the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401, the more clearance groove 303 makes room for the tab 401, and the less interference there is. If the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 is less than 2.3, the ratio is too small. Given a fixed thickness H0 of the tab 401, the width of the clearance groove 303 is too small, and it cannot provide sufficient bending and turning space for the tab 401. This makes it easy for the protective plate 3 to interfere with the tab 401, potentially leading to… If the bending point of the tab 401 is damaged, it will affect the battery performance. If the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 is greater than 11.7, the ratio is too large. Although the clearance groove 303 provides sufficient clearance space for the tab 401, the excessive width of the clearance groove 303 will result in the width of the solid part on the protection plate 3 being too small, weakening the structural strength of the protection plate 3, which is not conducive to the protection and support function of the protection plate 3, and may also cause the electrode group 4 to be under unbalanced pressure along the width direction. Therefore, by setting the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 within the range of 2.3-11.7, it can be ensured that the clearance groove 303 provides sufficient clearance space for the bending of the tab 401, preventing interference between the protection plate 3 and the tab 401, thereby avoiding damage to the tab 401, and also ensuring that the protection plate 3 has sufficient structural strength and avoiding uneven stress on the electrode group 4.

[0054] In one embodiment, further referring to Figures 4 and 10, the dimension of the clearance groove 303 along the length direction of the protective plate 3 is L1, and the dimension of the tab 401 along the length direction of the protective plate 3 is L2, wherein L1 is greater than L2, and the difference between L1 and L2 is 6mm-8mm. It should be noted that if the difference between the dimension L1 of the clearance groove 303 and the dimension L2 of the tab 401 along the length of the protective plate 3 is less than 6mm, then the clearance groove 303 is too small compared to the tab 401, which cannot provide enough space for the bending of the tab 401. The substrate 301 is likely to touch the tab 401, making it inconvenient to operate the tab 401 to bypass the protective plate 3. If the difference between the dimension L1 of the clearance groove 303 and the dimension L2 of the tab 401 is greater than 8mm, then the clearance groove 303 is too large compared to the tab 401. The clearance groove 303 occupies too much space on the substrate 301, which weakens the strength of the substrate 301 and reduces the contact area between the substrate 301 and the electrode group 4, which is not conducive to improving the uniformity of the force on the electrode group 4. Therefore, by setting the dimension L1 of the clearance groove 303 along the length direction to be larger than the dimension L2 of the electrode tab 401 along the length direction, and the increase of L1 over L2 being within the range of 6mm-8mm, it can be ensured that the clearance groove 303 provides sufficient space for the electrode tab 401 to prevent damage to the electrode tab 401, and the uniformity of force on the electrode tab 401 can also be improved. Here, the length direction refers to the "length direction" indicated by the arrow in Figure 4.

[0055] In one embodiment, the thickness H1 of the substrate 301 ranges from 0.8mm to 1.2mm. One side of the substrate 301 abuts against the support member 2 and the other side abuts against the electrode assembly 4. If the thickness H1 of the substrate 301 is less than 0.8mm, the thickness of the substrate 301 is too small, resulting in low structural strength, weak support strength, difficulty in ensuring the uniformity of stress on the electrode assembly 4, and difficulty in molding. If the thickness H1 of the substrate 301 is greater than 1.2mm, the thickness of the substrate 301 is too large, occupying too much space inside the battery, which will excessively compress the electrode assembly 4, causing damage to the electrode assembly 4 and affecting the performance of the battery. Furthermore, an excessively thick substrate 301 will increase the weight of the protection plate 3, which is not conducive to improving the energy density of the battery. Therefore, by setting the thickness H1 of the substrate 301 within the range of 0.8mm-1.2mm, it is possible to ensure that the substrate 301 can be smoothly formed and has sufficient structural strength, ensuring the uniformity of stress on the electrode assembly 4. It also prevents the protective plate 3 from occupying too much internal space of the battery and damaging the electrode assembly 4, and avoids the energy density of the battery being affected by excessive weight of the protective plate 3. Optionally, the thickness H1 of the substrate 301 is 1mm. Here, thickness refers to the dimension along the "height direction" indicated by the arrow in Figure 4.

[0056] In one embodiment, the height H2 of the support rib 302 ranges from 2.5mm to 3mm. The support rib 302 is supported between the base plate 301 of the protective plate 3 and the support member 2. If the height of the support rib 302 is less than 2.5mm, the height of the support rib 302 is too small, the distance between the support rib 302 and the bottom surface of the recess 203 is too large, the support rib 302 cannot abut against the support member 2 through the tab 401, the support rib 302 cannot play a supporting role, the stability of the protective plate 3 is poor, and there may be poor contact force between the middle section of the protective plate 3 and the electrode group 4, resulting in the boss damaging the electrode group 4 locally. If the height of the support rib 302 is greater than 3mm, the height of the support rib 302 is too large, exceeding the accommodation range of the recess 203, resulting in the support rib 302 excessively squeezing the tab 401, causing damage to the tab 401. Therefore, by setting the height H2 of the support rib 302 within the range of 2.5mm-3mm, it is possible to ensure that the support rib 302 can provide stable support between the substrate 301 and the support member 2, thereby improving the stability of the protective plate 3 and preventing local damage to the electrode group 4 and the corresponding boss caused by poor contact between the middle section of the protective plate 3 and the electrode group 4. Furthermore, it is also possible to prevent excessive compression of the support rib 302 from damaging the electrode tab 401. Here, height refers to the dimension along the "height direction" indicated by the arrow in Figure 4.

[0057] In one embodiment, the dimension W2 of the support rib 302 along the width direction of the protective plate 3 ranges from 3mm to 5mm. The support rib 302 is disposed on the substrate 301, and at least a portion of the support rib 302 corresponds to the clearance groove 303. If the width dimension W2 of the support rib 302 is less than 3mm, the width of the support rib 302 is too small, resulting in low structural strength, easy bending, and weak support capacity. If the width dimension W2 of the support rib 302 is greater than 5mm, the width dimension of the support rib 302 is too large, occupying too much space in the width direction of the protective plate 3. Correspondingly, it will compress the width dimension of the clearance groove 303. If the width dimension of the clearance groove 303 is too small, it cannot provide enough space for the bending of the tab 401, which can easily damage the tab 401 and thus affect the performance of the battery. Therefore, by setting the width W2 of the support rib 302 to be within the range of 3mm-5mm, it is possible to ensure that the support rib 302 has sufficient support strength and that the clearance groove 303 has sufficient width, thereby avoiding damage to the tab 401.

[0058] In one embodiment, the distance W3 between the support rib 302 and the clearance groove 303 ranges from 1.5mm to 2.5mm. If the distance between the support rib 302 and the clearance groove 303 is less than 1.5mm, the support rib 302 and the clearance groove 303 are too close, and the tab 401 is easily damaged after bending. If the distance between the support rib 302 and the clearance groove 303 is greater than 2.5mm, the support rib 302 and the clearance groove 303 are too far apart. Since the width of the substrate 301 is fixed, the design space left for the support rib 302 along the width direction of the substrate 301 is too small, resulting in the support rib 302 being too narrow. This leads to low structural strength of the support rib 302, making it easy to be bent, resulting in weak support capacity and an increased damage rate of the tab 401. Therefore, by setting the distance W3 between the support rib 302 and the clearance groove 303 to be within the range of 1.5mm-2.5mm, it can ensure that there is enough space for bending of the tab 401, that there is enough clearance for bending of the tab 401, and that the tab 401 is not damaged. At the same time, it can ensure that the support rib 302 has sufficient support strength and improve the structural stability.

[0059] In one embodiment, a buckle 304 is provided on the side of the substrate 301 facing the support member 2, and a corresponding slot 204 is provided on the side of the support member 2 facing the protective plate 3. The buckle 304 engages with the slot 204. By providing the buckle 304 on the substrate 301 and the corresponding slot 204 on the protective plate 3, the assembly of the substrate 301 and the protective plate 3 is achieved through the cooperation of the buckle 304 and the slot 204. The buckle 304 and the slot 204 have simple structures, are easy to form, and have a firm and reliable engagement. The engagement process is easy to operate, which helps to improve the stability of the protective plate 3 and the support member 2 after assembly and improves the assembly efficiency.

[0060] Optionally, there are two buckles 304. One buckle 304 is provided on each side of the support rib 302 along the length of the protective plate 3. A slot 204 is provided on the first boss 201 and the second boss 202 of the support member 2. The two buckles 304 and the two slots 204 are matched one-to-one. The protective plate 3 is connected to the bosses at both ends of the support member 2 to improve the stability of the assembly of the protective plate 3 and the support member 2.

[0061] In one embodiment, the snap fastener 304 includes two spaced-apart snap-fit ​​portions 305. Each snap-fit ​​portion 305 includes a connecting section 315 and a hook 325. The connecting section 315 connects the substrate 301 and the hook 325. Each hook 325 is bent away from the other hook 325. By providing two spaced-apart snap-fit ​​portions 305 with hooks 325 extending in opposite directions, when the snap fastener 304 is inserted into the slot 204, the sidewall of the slot 204 presses against the hook 325, causing the connecting section 315 to undergo slight elastic deformation. The tops of the two snap-fit ​​portions 305 move closer to each other, facilitating the entry of the hook 325 into the slot 204. After the hook 325 enters the slot 204, the connecting section 315 springs back, thus snapping the snap fastener 304 into the slot 204. This facilitates the snap fastener 304's entry into the slot 204 and provides high stability after assembly.

[0062] Optionally, the slot 204 is a through hole through the solid part of the boss. The distance between the outer edges of the two hooks 325 corresponding to each buckle 304 is greater than the size of the corresponding through hole. The boss refers to the first boss 201 and / or the second boss 202. A chamfer is provided on the side of the hook 325 away from the connecting section 315 to form a guide surface 335. During the process of the buckle 304 being inserted into the slot 204, the guide surface 335 provides guidance for the buckle 304, making it easier for the hook 325 to pass through the slot 204.

[0063] In other embodiments, the substrate 301 and the support member 2 are thermally fused together. During assembly, after the protective plate 3 and the support member 2 are aligned, the bosses of the substrate 301 and the support member 2 are hot-pressed. After the substrate 301 and the bosses are fused, the protective plate 3 is fixed to the bosses at both ends of the support member 2, thus achieving a fixed connection between the protective plate 3 and the support member 2. By hot-pressing to fix the substrate 301 and the bosses, no additional connection structure is required. The structure of the protective plate 3 and the support member 2 is simple, the hot-melt process is easy to operate, and the cost is low.

[0064] The following describes an actual production example, comparing and analyzing the damage to electrode group 4 after the cover plate assembly with added protective plate 3 and the cover plate assembly without protective plate 3 were welded into the shell.

[0065] Table 1. Statistics on the Percentage of Pressure Injuries in the Polar Group

[0066] It should be noted that after battery assembly, any damage to the electrode assembly constitutes a defect, and the electrode assembly damage ratio represents the percentage of defective products. For the batteries in Examples 1 to 6, a protection plate 3 was added, and all parameters on the protection plate 3 were within the range defined in this application. Each example includes several batteries, and the percentage of batteries with damaged tabs in that group is the electrode assembly damage ratio for that example. For the batteries in Comparative Examples 1 to 6, there is no protection plate 3. The difference between each example and its corresponding comparative example lies only in the presence or absence of the protection plate 3; the other battery structures are the same. Specifically, Comparative Example 1 corresponds to Example 1, Comparative Example 2 corresponds to Example 2, and so on. As shown in Table 1, the electrode assembly damage ratio of the batteries with the added protection plate 3 is lower than that of the batteries without the protection plate 3. This means that adding the protection plate 3 can effectively improve the situation where uneven force on the electrode assembly during traditional cover plate insertion leads to localized damage, greatly improving the battery assembly yield.

[0067] The following describes the assembly results of batteries assembled with protection boards using different parameter values, in order to verify the parameter values ​​of protection board 3.

[0068] Table 2 shows the statistical results of the proportion of electrode damage when the ratio of the dimension W1 of the clearance groove 303 along the width direction and the dimension W1 of the clearance groove 303 along the width direction to the thickness H0 of the electrode tab 401 are taken with different values.

[0069] Table 2. Statistics on the percentage of electrode damage corresponding to different sizes of clearance grooves and their ratio to electrode thickness.

[0070] As shown in Table 2, for the batteries of Examples 7 to 14, the width W1 of the clearance groove 303 on the protection plate 3 is in the range of 2.3mm-3.5mm, the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 is in the range of 2.3 to 11.7, and the proportion of tab damage is in the range of 0.39% to 0.62%, which is relatively small. For the batteries of Comparative Examples 7 and 8, the width W1 of the clearance groove 303 is less than 2.3mm, which is not within the range limited by this application, and the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 is less than 2.3, which is also not... Within the scope defined in this application, the percentages of tab damage were 3.65% and 2.3%, respectively, both higher than the percentages of tab damage in Examples 7 to 14. For the batteries of Comparative Examples 9 and 10, the width W1 of the clearance groove 303 was greater than 3.5 mm, which is also outside the scope defined in this application. The ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 was also greater than 11.7, which is also outside the scope defined in this application. The percentages of tab damage were 0.94% and 1.01%, respectively, which are lower than the percentages of tab damage in Comparative Examples 7 and 8, but still higher than the percentages of tab damage in Examples 7 to 14. In summary, when the width W1 of the clearance groove 303 is within the scope defined in this application and the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 is also within the scope defined in this application, the percentage of tab damage after battery assembly is relatively small. That is, when the width W1 of the clearance groove 303 and the ratio of the width W1 of the clearance groove 303 to the thickness H0 of the tab 401 are both within the range defined in this application, the damage to the tab can be reduced and the battery assembly yield can be greatly improved.

[0071] Table 3 shows the statistical results of the proportion of electrode ear damage when the distance W3 between the support rib 302 and the clearance groove 303 on the protective plate 3 takes different values.

[0072] Table 3. Statistics on the percentage of tab damage corresponding to different distances between the support rib and the clearance groove.

[0073] As shown in Table 3, for the batteries of Examples 15 to 22, the distance W3 between the support rib 302 and the clearance groove 303 is in the range of 1.5mm-2.5mm, and the percentage of tab damage is in the range of 0.53% to 0.84%. For the batteries of Comparative Examples 11 and 12, the distance W3 between the support rib 302 and the clearance groove 303 is less than 1.5mm, which is not within the range defined in this application, and the percentages of tab damage are 2.41% and 1.69%, respectively, both higher than the percentages of tab damage in Examples 15 to 22. For the batteries of Comparative Examples 13 and 14, the distance W3 between the support rib 302 and the clearance groove 303 is greater than 2.5mm, which is not within the range defined in this application, and the percentages of tab damage are 1.54% and 2.31%, respectively, both higher than the percentages of tab damage in Examples 15 to 22. In summary, when the distance W3 between the support rib 302 and the clearance groove 303 is within the range defined in this application, the proportion of tab damage after battery assembly is lower than the proportion of tab damage after battery assembly when the distance W3 between the support rib 302 and the clearance groove 303 is not within the range defined in this application. That is, when the distance W3 between the support rib 302 and the clearance groove 303 is within the range defined in this application, tab damage can be reduced, and battery assembly yield can be greatly improved.

[0074] According to an embodiment of this application, another aspect provides a battery, as shown in Figures 10 to 13. The battery includes: a housing 5, an electrode assembly 4, and the aforementioned cover plate assembly. The housing 5 has an open end; the electrode assembly 4 is placed inside the housing 5, and the electrode assembly 4 has tabs 401; the cover plate assembly is disposed at the open end of the housing 5, the support member 2 and the protective plate 3 are located inside the housing 5, the protective plate 3 abuts against the electrode assembly, and the cover plate 1 is welded to the housing 5 to seal the housing 5. The battery of this embodiment, by using the protective plate 3 between the support member 2 and the electrode assembly 4, can effectively improve the situation where the electrode assembly 4 is locally damaged due to uneven force when the cover plate assembly is inserted into the housing, greatly improving the battery assembly yield. Furthermore, the implementation method is simple and basically does not increase costs. Optionally, the battery is a lithium-ion battery.

[0075] In this embodiment, by adding a protective plate 3 between the support member 2 and the electrode group 4, the battery can effectively improve the situation in the traditional solution where the electrode group 4 is locally damaged due to uneven force when the cover plate assembly is inserted into the shell, which greatly improves the battery assembly yield and is simple to implement with virtually no increase in cost.

[0076] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A cover assembly, characterized by The application relates to a cover plate assembly. The cover plate assembly comprises a cover plate, a support arranged on one side of the cover plate, and a protection plate arranged on the side of the support away from the cover plate. The first and second bosses on the support are arranged at intervals along the length direction of the support, and the first boss and the second boss are raised towards the side away from the cover plate, and a recess is formed between the first boss and the second boss. The recess is adapted to accommodate the tab on the pole group.

2. The cover plate assembly of claim 1, wherein, The protection plate comprises a base plate and a support rib.

3. The cover plate assembly of claim 1, wherein, The support rib is fixedly connected to the base plate on the side of the base plate close to the support.

4. The cover plate assembly of claim 3, wherein, The base plate and the support on the support are in abutment.

5. The cover plate assembly of claim 1, wherein, The side of the base plate away from the support rib is a plane to abut the pole group. The base plate is provided with a relief groove for the tab to pass through.

6. The cover plate assembly of claim 1, wherein, The relief groove is arranged at intervals with the support rib. The support rib is located in the recess and abuts the bottom surface of the recess. The relief groove is open towards the side of the base plate.

7. The cover plate assembly of any one of claims 1 to 6, wherein, The size W1 of the relief groove along the width direction of the protection plate is 2.3-3.5 mm.

8. The cover plate assembly of claim 7, wherein, The ratio between the size W1 of the relief groove along the width direction of the protection plate and the thickness H0 of the tab is 2.3<=W1 / H0<=11.

7.

9. The cover plate assembly of any one of claims 1 to 6, wherein, The size of the relief groove along the length direction of the protection plate is L1, and the size of the tab along the length direction of the protection plate is L2.

10. A battery, characterized by The thickness H1 of the base plate is 0.8-1.2 mm. The height H2 of the support rib is 2.5-3 mm. The size W2 of the support rib along the width direction of the protection plate is 3-5 mm. The distance W3 between the support rib and the relief groove is 1.5-2.5 mm. The base plate is provided with a buckle towards the support. The support is provided with a clamping groove towards the protection plate. The buckle comprises two clamping portions arranged at intervals. Each clamping portion comprises a connecting segment and a clamping hook. The connecting segment is connected between the base plate and the clamping hook. Each clamping hook is bent away from the other clamping hook. The base plate and the support are hot-melt connected. The application relates to a cover plate assembly. The cover plate assembly comprises a cover plate, a support arranged on one side of the cover plate, and a protection plate arranged on the side of the support away from the cover plate. The cover plate assembly is arranged at the open end of the shell. The support and the protection plate are located in the shell. The cover plate is welded to the shell to close the shell.

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