Cover plate assembly and lithium ion battery

Abstract

The utility model provides a cover plate assembly and a lithium ion battery. The cover plate assembly comprises a cover plate body, a lower insulating part laminated with the cover plate body, a pole arranged on the cover plate body and an anti-explosion valve, the pole sequentially penetrates through the lower insulating part and the cover plate body, a pole bottom plate is arranged on the side, away from the cover plate body, of the pole, a first protruding part and a second protruding part are arranged on the side, away from the cover plate body, of the lower insulating part, the first protruding part corresponds to the anti-explosion valve in position, and the second protruding part is located at the end, away from the first protruding part, of the lower insulating part; the surface, far away from the cover plate body, of the second protruding part comprises a plane area and a curved surface area which are connected, the curved surface area is arranged close to the pole bottom plate, the minimum size of the orthographic projection of the curved surface area on the cover plate body in the length direction is L1, the minimum distance between the plane area and the pole bottom plate is L0, and L1 / L0 is larger than or equal to 0.5 and smaller than or equal to 0.9. The cover plate assembly and the lithium ion battery provided by the utility model are simple in structure and convenient to manufacture, and can effectively avoid the crushing phenomenon of the electrode assembly and ensure the stability of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate assembly and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are rechargeable batteries that primarily function by the movement of lithium ions between the positive and negative electrodes. Their working principle is as follows: during charging, lithium ions are extracted from the positive electrode, pass through the electrolyte, and embed into the negative electrode, leaving the negative electrode in a lithium-rich state; during discharging, the reverse occurs, with lithium ions migrating from the negative electrode to the positive electrode, releasing the stored energy. Lithium-ion batteries typically consist of a casing and a cover assembly, with the electrode assembly housed within the casing. The electrode assembly mainly comprises the connecting body and tabs, while the cover assembly mainly consists of riveting components, terminals, the cover body, upper insulation components, and lower insulation components. Currently, some lithium-ion batteries experience damage to the electrode assembly caused by the cover assembly; therefore, there is an urgent need for a lithium-ion battery that avoids this damage. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a cover plate assembly and a lithium-ion battery to solve the related problems mentioned in the background art.

[0004] In a first aspect, this application provides a cover plate assembly, comprising: a cover plate body, a lower insulating member stacked with the cover plate body, an electrode post disposed on the cover plate body, and an explosion-proof valve; the electrode post sequentially penetrates the lower insulating member and the cover plate body, and an electrode post base plate is provided on the side of the electrode post away from the cover plate body; the lower insulating member is provided with a first protrusion and a second protrusion on the side away from the cover plate body, the first protrusion corresponding to the position of the explosion-proof valve, and the second protrusion located at the end of the lower insulating member away from the first protrusion; the side of the second protrusion away from the cover plate body includes a connected planar area and a curved area, the curved area being disposed close to the electrode post base plate, the orthographic projection of the curved area on the cover plate body being a first projection, the minimum dimension of the first projection in the length direction of the cover plate assembly being L1, and the minimum distance between the planar area and the electrode post base plate being L0, satisfying 0.5≤L1 / L0≤0.9.

[0005] Furthermore, the dimension of the first projection along the length direction of the cover plate assembly is 0.1 mm to 2 mm.

[0006] Furthermore, the length of the cover plate assembly is 50mm to 150mm, and the minimum distance between the second protrusion and the pole base plate is greater than 0mm and less than or equal to 10mm.

[0007] Furthermore, a portion of the second protrusion near the base plate of the pole post extends toward the base plate of the pole post to form a cantilever, and the curved area is formed on the side of the cantilever away from the cover plate body.

[0008] Furthermore, the thickness of the cantilever is 0.1 mm to 1 mm.

[0009] Furthermore, a transition section is provided on the side of the cantilever near the cover plate body.

[0010] Furthermore, both the transition section and the curved surface area have rounded corners. The radius of the rounded corners of the curved surface area is 0.7 mm to 2 mm, and the radius of the rounded corners of the transition section is equal to the radius of the rounded corners of the curved surface area minus the thickness of the cantilever.

[0011] Furthermore, the second protrusion is provided with a cantilever, the size of which is less than or equal to the size of the second protrusion along the width direction of the cover plate assembly.

[0012] Furthermore, the second protrusion is connected to a plurality of cantilever arms, which are spaced apart along the width direction of the cover plate body.

[0013] Furthermore, the second protrusion has an opening groove on the side near the cover plate body, and the bottom of the opening groove away from the cover plate body has a through hole.

[0014] Furthermore, the through holes are spaced apart from the curved surface area.

[0015] A second aspect of this application provides a lithium-ion battery, comprising: a housing; a cover assembly as described in the first aspect above, the cover assembly enclosing the housing; an electrode assembly disposed within the housing, the electrode assembly including a body and tabs extending from the body, the tabs being connected to a base plate; and a minimum distance between the tabs and a second protrusion greater than or equal to 1 mm and less than or equal to 3 mm.

[0016] As can be seen from the above description, the cover plate assembly and lithium-ion battery provided in this application include: a cover plate body, a lower insulating member stacked with the cover plate body, an electrode post disposed on the cover plate body, and an explosion-proof valve; the electrode post passes through the lower insulating member and the cover plate body in sequence, and an electrode post base plate is provided on the side of the electrode post away from the cover plate body; a first protrusion and a second protrusion are provided on the side of the lower insulating member away from the cover plate body, the first protrusion corresponds to the position of the explosion-proof valve, and the second protrusion is located at the end of the lower insulating member away from the first protrusion; the side of the second protrusion away from the cover plate body includes a connected planar area and a curved area, the curved area is disposed close to the electrode post base plate, the orthographic projection of the curved area on the cover plate body is the first projection, the minimum dimension of the first projection in the length direction of the cover plate assembly is L1, and the minimum distance between the planar area and the electrode post base plate is L0, satisfying 0.5≤L1 / L0≤0.9. By incorporating both planar and curved areas in the second protrusion, the contact area between the second protrusion and the electrode assembly can be increased, reducing the pressure on the contact surface. This is especially beneficial under conditions of impact and vibration, preventing damage to the electrode assembly. Furthermore, by limiting the L1 / L0 ratio, battery stability is ensured. This avoids situations where the first projection ratio is too large, resulting in an excessively close distance between the second protrusion and the electrode tab, leading to spatial interference; conversely, it also avoids situations where the first projection ratio is too small, resulting in a small contact area between the second protrusion and the electrode assembly, making it susceptible to damage. This lithium-ion battery has a simple structure, is easy to manufacture, and effectively prevents electrode assembly damage, ensuring battery stability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a lithium-ion battery according to an embodiment of this application;

[0019] Figure 2 This is an exploded view of a cover plate assembly in an embodiment of this application;

[0020] Figure 3 for Figure 2 A partial cross-sectional schematic diagram of the mating of the middle cover plate assembly and the electrode assembly;

[0021] Figure 4 This is a schematic diagram of another type of cover plate assembly and electrode assembly working together.

[0022] Reference numerals: 1. Cover plate body; 2. Upper insulating component; 3. Riveting component; 4. Lower insulating component; 5. Electrode post; 5-1. Electrode post base plate; 6. Explosion-proof valve; 7. Second protrusion; 7-1. Planar area; 7-2. Curved area; 7-3. Cantilever; 7-4. Transition part; 7-5. Opening groove; 7-6. Through hole; 8. Electrode assembly; 8-1. Main body; 8-2. Electrode tab; 9. Housing; 10. Cover plate assembly; 11. First protrusion. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0024] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] A lithium-ion battery is a rechargeable battery that primarily functions by the movement of lithium ions between the positive and negative electrodes. Its working principle is as follows: during charging, lithium ions are extracted from the positive electrode, pass through the electrolyte, and embed into the negative electrode, leaving the negative electrode in a lithium-rich state; during discharging, the reverse occurs, with lithium ions migrating from the negative electrode to the positive electrode, releasing the stored energy. A lithium-ion battery typically consists of a casing and a cover assembly, with the electrode assembly housed within the casing. The electrode assembly mainly comprises the connecting body and tabs, while the cover assembly mainly consists of riveting components, terminals, the cover body, an upper insulating component, and a lower insulating component.

[0026] In the process of developing this application, it was discovered that some lithium-ion batteries experience damage to the electrode assembly caused by the cover plate assembly. Analysis of this problem suggests that it is due to uneven pressure distribution between the cover plate assembly and the electrode assembly, resulting in damage. Specifically, for example... Figure 1The diagram shows a schematic of a dual-channel battery cell. A dual-channel battery cell is a battery in which positive and negative electrode tabs extend from opposite ends of an electrode assembly 8. Correspondingly, the positive electrode tab is electrically connected to the positive electrode post of the positive electrode cover assembly located at one end of the housing 9, and the negative electrode tab is electrically connected to the negative electrode post of the negative electrode cover assembly located at the other end of the housing 9. Figure 2 The diagram shows a schematic of a cover plate assembly 10 for a dual-channel battery cell, such as a negative electrode cover plate assembly. The lower insulating member 4 has a protrusion at each end along its length L; these two protrusions abut against the body 8-1 of the electrode assembly 8 to support the electrode assembly 8. Due to the different contact areas on both sides, stress concentration occurs on the side with the smaller contact area, especially under impact or vibration conditions, which can easily damage the electrode assembly 8. Therefore, for such small-sized cells (e.g., dual-channel cells or ejector cells with a cover plate assembly length less than 150mm), there is an urgent need for a lithium-ion battery that avoids damage caused by pressure.

[0027] It is possible to consider increasing the contact area between the narrower protrusion of the cover plate assembly 10 and the electrode assembly 8 to reduce the pressure on the contact surface and avoid damaging the electrode assembly 8. However, because the protrusion and the electrode base plate 5-1 are spaced apart, for smaller cover plate assemblies 10 (e.g., the length of the cover plate assembly 10 is less than 150 mm and the width is less than 3 mm), the length of the cover plate assembly 10 is short, which limits the size design of the protrusion. If the contact surface between the protrusion and the main body 8-1 is simply extended along the plane, the increase in size is limited, the space utilization is low, and the improvement effect is insufficient. Through further research and development, this application provides a solution in which a curved area 7-2 is added to the protrusion, thereby increasing the contact area between the protrusion and the electrode assembly 8 in the same space, thus protecting the electrode assembly 8.

[0028] The following describes specific embodiments in conjunction with the appendix. Figures 1 to 4 The technical solution of this application will be described in further detail.

[0029] In some embodiments of this application, a cover plate assembly 10 is provided, including: a cover plate body 1, a lower insulating member 4 stacked with the cover plate body 1, an electrode post 5 disposed on the cover plate body 1, and an explosion-proof valve 6; the electrode post 5 passes through the lower insulating member 4 and the cover plate body 1 in sequence, and an electrode post base plate 5-1 is provided on the side of the electrode post 5 away from the cover plate body 1; the lower insulating member 4 is provided with a first protrusion 11 and a second protrusion 7 on the side away from the cover plate body 1, the first protrusion 11 corresponding to the position of the explosion-proof valve 6, and the second protrusion... 7 is located at the end of the lower insulating member 4 away from the first protrusion 11; the side of the second protrusion 7 away from the cover plate body 1 includes a connected planar area 7-1 and a curved area 7-2. The curved area 7-2 is located close to the pole base plate 5-1. The orthographic projection of the curved area 7-2 on the cover plate body 1 is the first projection. The minimum dimension of the first projection in the length direction of the cover plate assembly 10 is L1. The minimum distance between the planar area 7-1 and the pole base plate 5-1 is L0, satisfying 0.5≤L1 / L0≤0.9.

[0030] like Figure 2 The diagram shows an exploded view of a cover plate assembly 10, where L represents the length of the cover plate assembly 10 and W represents its width. The cover plate assembly 10 includes a cover plate body 1, which may be, for example, an aluminum plate, but is not specifically limited thereto. The cover plate assembly 10 includes a terminal post 5 penetrating the cover plate body 1, which may be, for example, a positive or negative terminal post. One end of the terminal post 5 is located on the side of the cover plate body 1 facing the electrode assembly 8, where a terminal post base plate 5-1 is provided for electrical connection with the electrode tab 8-2 of the electrode assembly 8; the other end of the terminal post 5 is located on the side of the cover plate body 1 away from the electrode assembly 8, for electrical connection with an external circuit. An upper insulating member 2 is provided on the side of the cover plate body 1 away from the electrode assembly 8, and a lower insulating member 4 is provided on the side closer to the electrode assembly 8. The insulating members are, for example, plastic, to ensure insulation between the cover plate body 1 and the terminal post 5. A riveting element 3 is provided on the side of the upper insulating member 2 facing away from the electrode assembly 8. The riveting element 3 is, for example, a conductive block, which can be electrically connected to an external circuit. The pole post 5 passes through the lower insulating member 4, the cover plate body 1, and the upper insulating member 2 in sequence, and is riveted and fixed to the riveting element 3. Those skilled in the art should know that this embodiment is illustrated by taking a riveted pole post as an example. In other embodiments of this application, it can also be an injection-molded pole post.

[0031] like Figure 3 As shown, Figure 2A partial cross-sectional diagram of the middle cover plate assembly 10 and the electrode assembly 8 is shown. The electrode assembly 8 includes a connecting body 8-1 and a tab 8-2. The lower insulating member 4 has a first protrusion 11 and a second protrusion 7 on the side near the electrode assembly 8. The protrusions are, for example, cuboid structures, but are not specifically limited. The protrusions abut against the body 8-1 for support and can also cooperate with the housing 9. The cover plate body 1 is equipped with an explosion-proof valve 6. In the event of battery thermal runaway, high-temperature gas can be discharged from the housing 9 through the explosion-proof valve 6 to prevent an explosion. The first protrusion 11 corresponds to the position of the explosion-proof valve 6, and the second protrusion 7 is located at the end of the lower insulating member 4 away from the first protrusion 11. The length of the first protrusion 11 is greater than the length of the second protrusion 7.

[0032] The second protrusion 7, near the electrode assembly 8, includes a connected planar area 7-1 and a curved area 7-2. The curved area 7-2 is located near the electrode base plate 5-1, and its cross-sectional shape is, for example, a downwardly convex arc, without specific limitation. The planar area 7-1 directly abuts against the main body 8-1, while the curved area 7-2 abuts against the main body 8-1 or the tab 8-2 when the electrode assembly 8 is compressed. By providing the planar area 7-1 and the curved area 7-2 in the second protrusion 7, the contact area between the second protrusion 7 and the electrode assembly 8 is increased, which can reduce the pressure on the contact surface. Especially under conditions such as impact and vibration, it can prevent damage to the electrode assembly 8. In the same space, the curved area 7-2 has a larger contact area than the planar design, and it is more compatible with the root of the tab 8-2, resulting in higher space utilization. While improving the damage phenomenon, it can also increase the battery energy density.

[0033] like Figure 3 As shown, the orthographic projection of the curved area 7-2 onto the cover plate body 1 is the first projection. The minimum dimension of the first projection along the length of the cover plate assembly 10 is L1, and the minimum distance between the planar area 7-1 and the electrode base plate 5-1 is L0, satisfying 0.5≤L1 / L0≤0.9. For example, L1 / L0 can be 0.5, 0.6, 0.7, 0.8, or 0.9, etc., without specific limitations. By limiting the ratio of L1 / L0, battery stability is ensured, avoiding an excessively large proportion of the first projection, which would result in the second protrusion 7 being too close to the electrode tab 8-2, causing spatial interference; and also avoiding an excessively small proportion of the first projection, which would result in a small contact area between the second protrusion 7 and the electrode assembly 8, making it easy to damage the electrode assembly 8.

[0034] The cover plate assembly 10 has a simple structure and is easy to manufacture. It can effectively avoid the damage to the electrode assembly 8 and ensure the stability of the battery.

[0035] In some embodiments, the dimension of the first projection along the length direction of the cover plate assembly 10 is 0.1 mm to 2 mm.

[0036] like Figure 3As shown, the first projected length L1 of the curved area 7-2 is 0.1mm to 2mm, for example, L1 is 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, 1.5mm or 2mm, etc., and there is no specific limitation, which can ensure the stability of the battery. The connection between the tab 8-2 and the main body 8-1 is usually chamfered, or the tab 8-2 may be misaligned during manufacturing and become larger. If the first projected length is too long, the distance between the curved area 7-2 and the tab 8-2 will be too close, and it will be subject to spatial interference. In addition, if the curved area 7-2 is too long, it will also greatly reduce the contact area between the flat area 7-1 and the main body 8-1, resulting in poor battery stability. If the first projected length is too short, the contact area between the second protrusion 7 and the electrode assembly 8 will be small, and the electrode assembly 8 will still be easily damaged. The length L2 of the planar region 7-1 is 4mm to 10mm, for example, L2 is 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc., and there is no specific limitation. If the length of the planar region 7-1 is too long, it will affect the layout of the tab 8-2; if the length of the planar region 7-1 is too short, it will damage the electrode assembly 8.

[0037] In some embodiments, the length of the lower insulating member 4 is 116 mm, the length of the first protrusion 11 is 55 mm, the length of the planar region 7-1 of the second protrusion 7 is 4 mm, and the length of the first projection is 1.5 mm.

[0038] In some embodiments, the length of the cover plate assembly 10 is 50 mm to 150 mm, and the minimum distance between the second protrusion 7 and the pole base plate 5-1 is greater than 0 mm and less than or equal to 10 mm.

[0039] The length of the cover assembly 10 is, for example, 50mm, 70mm, 100mm, 120mm, or 150mm, etc., without specific limitation, to ensure the energy density of the battery. The minimum distance between the second protrusion 7 and the terminal base plate 5-1 is greater than 0mm and less than or equal to 10mm, for example, the distance is 1mm, 3mm, 5mm, 7mm, or 10mm, etc., without specific limitation, which can improve space utilization.

[0040] In some embodiments, a portion of the second protrusion 7 on the side near the pole base plate 5-1 extends toward the pole base plate 5-1 to form a cantilever 7-3, and a curved area 7-2 is formed on the side of the cantilever 7-3 away from the cover plate body 1.

[0041] like Figure 4The diagram shows another structural schematic of the cover plate assembly 10 and the electrode assembly 8. In the diagram, the bottom of the second protrusion 7 near the electrode base plate 5-1 extends towards the electrode base plate 5-1 to form a cantilever 7-3. The cantilever 7-3 can be integrally formed with the second protrusion 7. The surface of the cantilever 7-3 facing away from the cover plate body 1 has a transition design, forming the aforementioned curved surface area 7-2. By setting the cantilever 7-3, not only is the contact area between the second protrusion 7 and the electrode assembly 8 increased, but the buffering effect is also improved. Because the cantilever 7-3 is relatively thin and has a certain degree of flexibility, when the battery is subjected to impact, vibration, or other conditions, the cantilever 7-3 is easily deformed by compression, absorbing the impact force of the electrode assembly 8 and playing a buffering role, further preventing damage to the electrode assembly 8.

[0042] In some embodiments, the thickness of the cantilever 7-3 is 0.1 mm to 1 mm.

[0043] At the connection between the cantilever 7-3 and the second protrusion 7, the thickness of the cantilever 7-3 is, for example, 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, or 1 mm, etc., with no specific limitation, but preferably 0.7 mm, which can ensure the structural stability of the cantilever 7-3. This avoids the cantilever 7-3 being too thick, resulting in poor flexibility and reduced buffering effect on the electrode assembly 8; it also avoids the cantilever 7-3 being too thin, resulting in poor connection strength and easy breakage.

[0044] In some embodiments, the cantilever 7-3 has a transition portion 7-4 on the side near the cover plate body 1.

[0045] like Figure 4 As shown, a transition portion 7-4 is provided on the side of the cantilever 7-3 near the cover plate body 1. The transition portion 7-4 is located near the pole lug 8-2. The transition portion 7-4 is, for example, an angled or rounded corner, to facilitate the deformation of the cantilever 7-3 when it is squeezed.

[0046] In some embodiments, both the transition portion 7-4 and the curved surface region 7-2 are rounded corners, the radius of the rounded corner of the curved surface region 7-2 is 0.7 mm to 2 mm, and the radius of the rounded corner of the transition portion 7-4 is equal to the radius of the rounded corner of the curved surface region 7-2 minus the thickness of the cantilever 7-3.

[0047] Both the transition section 7-4 and the curved surface area 7-2 can be set to rounded corners. The rounded corner radius of the curved surface area 7-2 can be, for example, 0.7mm, 1mm, 1.5mm or 2mm, and the rounded corner radius of the transition section 7-4 can be, for example, 0.6mm, 0.8mm or 1mm, etc. There are no specific limitations, which facilitates manufacturing and meets deformation requirements.

[0048] In some embodiments, the second protrusion 7 is provided with a cantilever 7-3, the size of which is less than or equal to the size of the second protrusion 7 along the width direction of the cover plate assembly 10.

[0049] The second protrusion 7 can be provided with only one cantilever 7-3 on the side near the electrode 8-2. This cantilever 7-3 extends along the width direction of the cover plate assembly 10, which can effectively increase the contact area between the second protrusion 7 and the electrode assembly 8. The structure is simple and easy to manufacture. Along the width direction of the cover plate assembly 10, the size of the cantilever 7-3 is less than or equal to the size of the second protrusion 7 to avoid interfering with battery assembly.

[0050] In some embodiments, the second protrusion 7 is connected to a plurality of cantilever arms 7-3, which are spaced apart along the width direction of the cover plate body 1.

[0051] The second protrusion 7 can be connected to multiple spaced-apart cantilevers 7-3 on the side near the electrode tab 8-2, such as two, three or four, etc., without any specific limitation. Because the cantilevers 7-3 are spaced-apart and the size of a single cantilevers 7-3 is relatively narrow, they are more likely to deform when squeezed, which further improves the buffering effect of the cantilevers 7-3 and avoids damaging the electrode assembly 8.

[0052] In some embodiments, the second protrusion 7 is provided with an opening groove 7-5 on the side near the cover plate body 1, and the bottom of the opening groove 7-5 away from the cover plate body 1 is provided with a through hole 7-6.

[0053] like Figure 3 As shown, the second protrusion 7 is a hollow structure with an open groove 7-5 inside and a through hole 7-6 at the bottom of the groove to facilitate the flow of electrolyte and avoid affecting the wetting effect of the electrode assembly 8.

[0054] In some embodiments, the through hole 7-6 is spaced apart from the curved surface area 7-2.

[0055] like Figure 3 As shown, the through hole 7-6 and the curved surface area 7-2 are spaced apart, which facilitates manufacturing and avoids affecting the contact area of ​​the curved surface area 7-2.

[0056] In some embodiments of this application, a lithium-ion battery is provided, comprising: a housing 9; a cover assembly 10 as described in any of the above embodiments, the cover assembly 10 enclosing the housing 9; an electrode assembly 8 disposed within the housing 9, the electrode assembly 8 comprising a main body 8-1 and an electrode tab 8-2 extending from the main body 8-1, the electrode tab 8-2 being connected to an electrode post base plate 5-1; the minimum distance between the electrode tab 8-2 and the second protrusion 7 is greater than or equal to 1 mm and less than or equal to 3 mm.

[0057] like Figure 1 The diagram shows a schematic of a lithium-ion battery. The lithium-ion battery includes a housing 9, an electrode assembly 8, and a cover assembly 10. The housing 9 is, for example, an aluminum housing, and can be welded to the cover assembly 10.

[0058] The minimum distance between the second protrusion 7 and the tab 8-2 is greater than or equal to 1 mm and less than or equal to 3 mm. For example, the distance is 1 mm, 2 mm or 3 mm, etc., and there is no specific limitation. This ensures the energy density of the battery and avoids affecting the battery assembly.

[0059] This lithium-ion battery can be used in electrical devices, including vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0060] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the above embodiments of this application, which are not provided in detail for the sake of brevity.

[0061] Furthermore, given that details have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0062] Although this application has been described in conjunction with embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0063] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A cover assembly, characterized by The cover plate assembly comprises a cover plate body, a lower insulating member laminated with the cover plate body, a pole post arranged on the cover plate body, and an explosion-proof valve; The pole post penetrates the lower insulating member and the cover plate body in sequence, and a pole post bottom plate is arranged on the side of the pole post away from the cover plate body; a first protruding part corresponding to the position of the explosion-proof valve and a second protruding part located at the end of the lower insulating member away from the first protruding part are arranged on the side of the lower insulating member away from the cover plate body; the side of the second protruding part away from the cover plate body comprises a connected planar area and a curved area, the curved area is arranged close to the pole post bottom plate, the first projection of the curved area on the cover plate body is a first projection, the minimum size of the first projection in the length direction of the cover plate assembly is L1, and the minimum distance between the planar area and the pole post bottom plate is L0, and 0.5≤L1 / L0≤0.9 is satisfied.

2. The cover plate assembly of claim 1, wherein, The size of the first projection in the length direction of the cover plate assembly is 0.1mm to 2mm.

3. The cover plate assembly of claim 2, wherein, The length of the cover plate assembly is 50mm to 150mm, the minimum distance between the second protruding part and the pole post bottom plate is greater than 0mm and less than or equal to 10mm.

4. The cover plate assembly of claim 1, wherein, The part of the second protruding part close to the side of the pole post bottom plate extends in the direction of the pole post bottom plate to form a cantilever, and the side of the cantilever away from the cover plate body forms the curved area.

5. The cover plate assembly of claim 4, wherein, The thickness of the cantilever is 0.1mm to 1mm.

6. The cover plate assembly of claim 4, wherein, The side of the cantilever close to the cover plate body is provided with a transition part.

7. The cover plate assembly of claim 6, wherein, The transition part and the curved area are both rounded, the radius of the rounded corner of the curved area is 0.7mm to 2mm, and the radius of the rounded corner of the transition part is equal to the radius of the rounded corner of the curved area minus the thickness of the cantilever.

8. The cover plate assembly of claim 4, wherein, The second protruding part is provided with one cantilever, and the size of the cantilever in the width direction of the cover plate assembly is less than or equal to the size of the second protruding part.

9. The cover plate assembly of claim 4, wherein, The second protruding part is connected with a plurality of cantilevers, and the plurality of cantilevers are arranged at intervals in the width direction of the cover plate body.

10. The cover plate assembly of claim 1, wherein, The side of the second protruding part close to the cover plate body is provided with an open slot, and the slot bottom of the open slot away from the cover plate body is provided with a through hole.

11. The cover plate assembly of claim 10, wherein, The through hole is arranged at intervals with the curved area.

12. A lithium-ion battery, characterized by, It comprises: a shell; the cover plate assembly of any one of claims 1-11, the cover plate assembly enclosing the shell; an electrode assembly arranged in the shell, the electrode assembly comprising a main body and a tab extending from the main body, the tab being connected with the pole post bottom plate; the minimum distance between the tab and the second protruding part is greater than or equal to 1mm and less than or equal to 3mm.

Images