A battery and its cap

Abstract

The application discloses a battery and a cover cap thereof, the cover cap comprising a top cover, a bursting disc and a sealing ring; the top cover is connected above the bursting disc; the sealing ring is located at the circumferential side of the top cover and the bursting disc; the circumferential side of the top cover is bent downward and continues to bend inward, forming a wrapping part which wraps the circumferential side of the bursting disc; the bursting disc comprises a first body part and a wrapped part located at the circumferential side of the first body part, and the wrapped part is wrapped by the wrapping part; the bursting disc and the sealing ring are isolated by the wrapping part. The battery and the cover cap thereof can solve the problem that the bursting disc is deformed under stress during assembly, thereby improving the air tightness of the cover cap and reducing the loss of the off value.

Description

Technical Field

[0001] This specification relates to the field of battery technology, and in particular to a battery and its cap. Background Technology

[0002] The cap of a cylindrical lithium-ion battery is an important safety sealing component of the battery. It mainly consists of a top cover, an explosion-proof sheet, a connecting aluminum sheet, an insulating ring, and a sealing ring. It not only performs the function of conducting electricity, but also has safety protection functions such as sealing and preventing leakage, overpressure relief, and overpressure circuit breaking. It directly determines the battery's sealing performance, service life, and safety performance.

[0003] To further improve the utilization rate of internal space in battery cells and increase battery energy density, the industry is gradually optimizing the traditional fully enclosed cap structure into a semi-enclosed cap structure. The semi-enclosed cap structure, such as... Figure 1 As shown. Traditional full-coverage caps use an explosion-proof sheet to cover the top cover. Existing semi-coverage caps eliminate this large-area edge covering structure, effectively freeing up space above the battery cell, increasing the amount of active material filling, and improving battery energy density, thus gaining widespread adoption. However, the existing semi-coverage structure has a significant drawback: After eliminating the edge covering of the explosion-proof sheet, during the cap sealing assembly process, the assembly pressure directly acts on the explosion-proof sheet. Simultaneously, the sealing ring accumulates on the shoulder of the explosion-proof sheet under pressure, causing the shoulder to deform and open, creating a gap where it fits with the top cover. This leads to two major defects:

[0004] First, airtightness defects. For example... Figure 2 As shown, the shoulder of the explosion-proof sheet 2' is squeezed open by the assembly sealing ring, creating a gap at the joint with the top cover 1'. Simultaneously, after the explosion-proof sheet 2' undergoes plastic deformation such as bending and stretching due to assembly compression, the welded joint surface between the explosion-proof sheet 2' and the top cover 1' partially opens, creating microscopic gaps on the contact surface and reducing the consistency of the interface adhesion. During long-term storage, charging and discharging, and high and low temperature cycling, the electrolyte is prone to leaking from the gap between the top cover 1' and the explosion-proof sheet 2', causing battery leakage, corrosion, increased self-discharge, and other adverse effects, seriously affecting battery reliability. Figure 2 The red circle in the image indicates the deformation of the explosion-proof sheet 2'. Figure 2 The red arrows in the image indicate the direction of the leak (air / liquid).

[0005] Secondly, the safety performance is unstable. Explosion-proof sheets are precision functional components; their power-off threshold and burst value are determined by material thickness, flatness, and internal stress. When the explosion-proof sheet is deformed and subjected to residual stress due to assembly forces, its internal structure changes, directly leading to a decrease in the explosion-proof sheet's breaking threshold, an overall low power-off value with large dispersion. This makes the battery prone to abnormal power-off, seriously affecting normal battery use and failing to meet the high-quality requirements of power and energy storage batteries.

[0006] Currently, the industry can only improve the situation by adjusting assembly pressure and optimizing pressing stroke, but it cannot avoid the stress on the explosion-proof sheet from the structural level. The optimization limit is low and it cannot meet the needs of mass production and high-end battery use. Summary of the Invention

[0007] In view of the shortcomings of the prior art, one object of this specification is to provide a battery and its cap that can solve the problem of deformation of the explosion-proof sheet under stress during assembly, thereby improving the airtightness of the cap and reducing power loss.

[0008] To achieve the above objectives, this specification provides a battery cap, comprising: a top cover, an explosion-proof sheet, and a sealing ring; the top cover is connected above the explosion-proof sheet; the sealing ring is located on the periphery of the top cover and the explosion-proof sheet; the periphery of the top cover is bent downwards and continues to bend inwards to form a rim portion, the rim portion wrapping around the periphery of the explosion-proof sheet; the explosion-proof sheet includes a first main body portion and a covered portion located on the periphery of the first main body portion, the covered portion being wrapped by the rim portion; the explosion-proof sheet and the sealing ring are separated by the rim portion.

[0009] In a preferred embodiment, the edging portion includes a first portion located above the covered portion, a second portion located below the covered portion, and a third portion located around the covered portion, the third portion being connected between the first portion and the second portion; the top cover also includes a second main body portion connected to the first portion; the axial thickness of the edging portion does not exceed the sum of the axial thicknesses of the first main body portion and the second main body portion.

[0010] In a preferred embodiment, the thickness of the second main body is greater than the thickness of the first part.

[0011] In a preferred embodiment, the thickness of the first part, the thickness of the second part, and the thickness of the third part are all equal; the first part, the second part, and the covered part are arranged in parallel.

[0012] In a preferred embodiment, the thickness of the first part is 50% to 70% of the thickness of the second main body.

[0013] In a preferred embodiment, the thickness of the first main body portion is greater than or equal to the thickness of the covered portion.

[0014] In a preferred embodiment, the thickness of the covered portion is 35% to 100% of the thickness of the first main body portion.

[0015] In a preferred embodiment, the upper surface of the first portion is flush with the upper surface of the second main body portion, and / or the lower surface of the second portion is flush with the lower surface of the first main body portion.

[0016] In a preferred embodiment, the upper surface of the covered portion is higher than the upper surface of the first main body portion.

[0017] In a preferred embodiment, the axial thickness of the edging portion is equal to the sum of the axial thicknesses of the first main body portion and the second main body portion.

[0018] In a preferred embodiment, the cap further includes a connecting aluminum sheet and an insulating ring; the connecting aluminum sheet is disposed below the explosion-proof sheet; and the insulating ring is provided between the periphery of the connecting aluminum sheet and the explosion-proof sheet.

[0019] In a preferred embodiment, the second main body, the first part, the second part, and the third part are integrally formed.

[0020] In a preferred embodiment, the first main body and the covered part are integrally formed.

[0021] This specification also provides a battery comprising: a cap as described in any of the preceding embodiments.

[0022] Beneficial effects:

[0023] The battery cap provided in this embodiment has the following advantages:

[0024] 1. Transferring the load-bearing body of the assembly and thoroughly protecting the explosion-proof sheet: This invention forms an edge portion by bending the periphery of the top cover downward to wrap around the periphery of the explosion-proof sheet, and designs the explosion-proof sheet as the first main body and the covered part located on the periphery. The explosion-proof sheet and the sealing ring are isolated by the edge portion, so that all the pressure during the assembly of the cap sealing is transferred to the top cover and its edge portion. The explosion-proof sheet no longer bears any assembly compression and bending stress, will not undergo plastic deformation, has no residual internal stress, and always maintains the original state of the factory.

[0025] 2. Significantly improves the airtightness of the cap and eliminates leakage: The edge tightly wraps around the covered part, ensuring a tight fit between the top cover and the explosion-proof sheet. This eliminates the opening of the contact surface and micro gaps caused by the deformation of the explosion-proof sheet, effectively preventing electrolyte from seeping and leaking from the welded contact surface, and improving battery storage life and cycle stability.

[0026] 3. Stable power-off threshold of explosion-proof sheet: The explosion-proof sheet is not affected by external forces during assembly, and its mechanical properties, circuit breaking pressure and burst pressure will not decrease. The power-off value range is stable and has small dispersion, avoiding abnormal problems such as false circuit breaking and premature power-off during normal battery charging and discharging, thus improving product yield and safety of use.

[0027] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0028] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0029] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic cross-sectional view of a cap provided in the prior art;

[0032] Figure 2 This is a scanned image of the battery cap in the prior art;

[0033] Figure 3 This is a cross-sectional structural diagram of a battery provided in this embodiment;

[0034] Figure 4 for Figure 3 Enlarged structural diagram at point A;

[0035] Figure 5 This is a schematic diagram of the structure of a battery cap provided in this embodiment;

[0036] Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure at point BB;

[0037] Figure 7 for Figure 6 A magnified structural diagram at point C.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1' Top cover; 2' Explosion-proof sheet;

[0040] 10. Cap; 20. Steel shell; 201. Grooved structure; 30. Core; 1. Top cover; 11. Second main body; 12. Edge banding; 121. First part; 122. Second part; 123. Third part; 13. Welding joint; 2. Explosion-proof sheet; 21. First main body; 22. Covered part; 3. Connecting aluminum sheet; 4. Isolation ring; 5. Sealing ring; X, Axial direction. Detailed Implementation

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

[0042] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] Please see Figures 3 to 7 This application provides a battery cap 10, comprising: a top cover 1, an explosion-proof sheet 2, and a sealing ring 5.

[0045] Among them, such as Figure 4 As shown, the top cover 1 is connected above the explosion-proof sheet 2. The sealing ring 5 is located around the top cover 1 and the explosion-proof sheet 2, used to insulate and seal the cap 10 to the battery's steel casing 20. Figure 3 As shown, the battery includes a steel casing 20, a winding core 30 disposed inside the steel casing 20, and a cap 10 connected above the winding core 30. The cap 10 and the steel casing 20 are insulated and sealed by a sealing ring 5. The cap 10 and the positive terminal of the winding core 30 are connected.

[0046] like Figure 6 and Figure 7As shown, the periphery of the top cover 1 bends downwards and continues to bend inwards to form a rimmed portion 12. The rimmed portion 12 wraps around the periphery of the explosion-proof sheet 2. The explosion-proof sheet 2 includes a first main body portion 21 and a covered portion 22 located around the periphery of the first main body portion 21, and the covered portion 22 is wrapped by the rimmed portion 12. The explosion-proof sheet 2 and the sealing ring 5 are separated by the rimmed portion 12.

[0047] The battery cap 10 provided in this embodiment has the following advantages:

[0048] 1. Transferring the load-bearing body of the assembly and thoroughly protecting the explosion-proof sheet 2: The present invention forms a wrapping part 12 by bending the top cover 1 downward around its periphery to wrap the periphery of the explosion-proof sheet 2. The explosion-proof sheet 2 is designed as a first main body part 21 and a covered part 22 located on the periphery. The explosion-proof sheet 2 and the sealing ring 5 are isolated by the wrapping part 12, so that all the pressure during the sealing assembly of the cap 10 is transferred to the top cover 1 and its wrapping part 12. The explosion-proof sheet 2 no longer bears any assembly compression and bending stress, will not undergo plastic deformation, has no residual internal stress, and always maintains the original state of the factory.

[0049] 2. Significantly improve the airtightness of the cap 10 and eliminate leakage: The edge 12 tightly wraps the covered part 22, so that the contact surface of the top cover 1 and the explosion-proof sheet 2 are tightly fitted, eliminating the opening of the contact surface and micro gaps caused by the deformation of the explosion-proof sheet 2, effectively preventing electrolyte from seeping and leaking from the welded contact surface, and improving the battery storage life and cycle stability.

[0050] 3. Stable power-off threshold of explosion-proof sheet 2: Explosion-proof sheet 2 is not affected by external assembly forces, and its mechanical properties, circuit breaking pressure and burst pressure will not decrease. The power-off value range is stable and has small dispersion, avoiding abnormal problems such as false circuit breaking and premature power-off during normal battery charging and discharging, thus improving product yield and safety of use.

[0051] It should be noted that the top cover 1 is generally made of steel, while the explosion-proof sheet 2 is generally made of aluminum. The hardness of the top cover 1 is generally much greater than that of the explosion-proof sheet 2. Therefore, the squeezing force from the sealing ring 5 during assembly can be perfectly transferred and borne by the top cover 1, fundamentally solving the problem of deformation of the explosion-proof sheet 2 under stress.

[0052] In this embodiment, such as Figure 7As shown, the edging portion 12 specifically includes a first portion 121 located above the covered portion 22, a second portion 122 located below the covered portion 22, and a third portion 123 located around the covered portion 22, with the third portion 123 connecting the first portion 121 and the second portion 122. The top cover 1 also includes a second main body portion 11 connected to the first portion 121. The axial X thickness of the edging portion 12 does not exceed the sum of the axial X thicknesses of the first main body portion 21 and the second main body portion 11. The axial X thickness of the edging portion 12 is the sum of the thicknesses of the first portion 121, the covered portion 22, and the second portion 122.

[0053] It is understandable that the thicknesses of both the first main body portion 21 and the second main body portion 11 are conventional thicknesses, and there are no special settings for them in the prior art; they are conventional parameters. The thicknesses of the first main body portion 21 and the second main body portion 11 can also use conventional parameters. However, for the first part 121, the covered part 22, and the second part 122, the lower end face of the total thickness of these three parts is close to the sealing ring 5, and then the sealing ring 5 is in contact with the battery's groove structure 201 (such as...). Figure 4 As shown, the lower edge of the groove structure 201 directly determines the actual height of the internal core 30 of the battery. Therefore, the lower end face of the total thickness of the first part 121, the covered part 22, and the second part 122 (i.e., the lower end face of the edge-wrapping part 12, which is also the lower end face of the second part 122) actually affects the final height of the core 30, so the total thickness of the first part 121, the covered part 22, and the second part 122 cannot be too high. In other words, the total thickness of the first part 121, the covered part 22, and the second part 122 should preferably not exceed the sum of the thicknesses of the conventional first main body part 21 and the second main body part 11.

[0054] That is, preferably, the sum of the thicknesses of the first part 121, the covered part 22, and the second part 122 does not exceed the sum of the thicknesses of the first main body part 21 and the second main body part 11.

[0055] As an optional embodiment, the sum of the thicknesses of the first part 121, the covered part 22, and the second part 122 is equal to the sum of the thicknesses of the first main body part 21 and the second main body part 11.

[0056] As another optional embodiment, the sum of the thicknesses of the first part 121, the covered part 22, and the second part 122 is less than the sum of the thicknesses of the first main body part 21 and the second main body part 11, and the sum of the thicknesses of the first part 121, the covered part 22, and the second part 122 is greater than or equal to 75% of the thicknesses of the first main body part 21 and the second main body part 11.

[0057] In a preferred embodiment, the thickness of the second main body 11 is greater than the thickness of the first part 121. This is because the thickness of the top cover 121 is generally greater than the thickness of the explosion-proof sheet 2. In order to ensure that the axial X thickness of the edge-wrapping part 12 does not exceed the sum of the axial X thicknesses of the first main body 21 and the second main body 11, the thickness of each part of the edge-wrapping part 12 needs to be thinned.

[0058] In one embodiment, the thicknesses of the first portion 121, the second portion 122, and the third portion 123 are all equal, meaning the thickness of the edging portion 12 is uniform throughout. This ensures balanced material flow and uniform stress distribution during the stamping process of the top cover 1, preventing stress concentration or molding defects caused by local thickness differences. Simultaneously, the uniform thickness guarantees the overall strength uniformity of the edging portion 12, allowing for uniform transmission and bearing of assembly pressure during the sealing assembly process. This ensures symmetrical force distribution in all directions around the explosion-proof sheet 2, further enhancing its effectiveness in protecting against external assembly forces.

[0059] Preferably, the first part 121, the second part 122, and the covered part 22 are arranged in parallel, so that the entire edge portion 12 forms a regular "U" or "C" shaped structure in the axial X-section. The first part 121 and the second part 122 clamp the covered part 22 in parallel from the top and bottom directions, respectively, thereby achieving uniform and tight surface contact between the top cover 1 and the explosion-proof sheet 2. The clamping force is evenly distributed along the entire covered area, and there will be no local stress concentration or point contact caused by angular deviation or unevenness. At the same time, the parallel fit ensures that the top cover 1 and the explosion-proof sheet 2 will not tilt or shift relative to each other during assembly, ensuring the overall coaxiality and structural stability of the cap 10, and further improving the fit consistency and airtight reliability of the sealing surface.

[0060] Specifically, the thickness of the first part 121 is 50% to 70% of the thickness of the second main body 11 (e.g., 50%, 55%, 60%, 65%, 70%, etc.), which gives the edge area of ​​the top cover 1 good bending performance during edge forming. Within this thickness range, the material is neither too thick to be difficult to bend and form, nor too thin to lack strength, ensuring that the edge part 12 can tightly wrap the covered part 22 of the explosion-proof sheet 2. At the same time, the extrusion thinning process effectively controls the axial X thickness of the edge part 12, and the overall shoulder height does not increase due to the edge structure, taking into account both processing feasibility and the requirements of high energy density.

[0061] In this embodiment, the thickness of the first main body 21 is greater than or equal to the thickness of the covered part 22. That is, the edge of the explosion-proof sheet 2 (the covered part 22) can be thinned or the original thickness can be kept unchanged.

[0062] In one embodiment, the thickness of the covered portion 22 is equal to the thickness of the first main body portion 21, meaning that the edge of the explosion-proof sheet 2 is not thinned. In this case, for the top cover 1, the thickness of its first portion 121 is 50% of the thickness of the second main body portion 11, thereby making the axial X thickness of the edge portion 12 equal to the sum of the axial X thicknesses of the first main body portion 21 and the second main body portion 11.

[0063] In other embodiments, the thickness of the covered portion 22 is less than the thickness of the first main body portion 21, that is, the edge area of ​​the explosion-proof sheet 2 is thinned. When the edge portion 12 wraps around the covered portion 22, the deformation resistance of the covered portion 22 is significantly reduced, allowing it to be more tightly embedded in the edge portion 12, making the fit between the top cover 1 and the explosion-proof sheet 2 tighter. At the same time, the thinning of the edge makes the explosion-proof sheet 2 occupy less space in the overall axial X thickness, which is beneficial to controlling the total height of the cap 10 and leaving more space for the active material to fill inside the battery cell.

[0064] Specifically, the thickness of the covered portion 22 is 35% to 100% of the thickness of the first main body portion 21 (e.g., 35%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc.), so that the covered area at the edge of the explosion-proof sheet 2 has good embedding and deformation compliance while ensuring sufficient structural strength. The lower limit of the thickness (35%) ensures that the covered portion 22 will not break or fracture under stress.

[0065] Preferably, the thickness of the covered portion 22 does not exceed 80% of the thickness of the first main body portion 21, ensuring that the covered portion 22 can be tightly embedded in the edge portion 12 of the top cover 1, achieving a tight fit between the edge portion 12 and the covered portion 22, compacting the mating surface between the top cover 1 and the explosion-proof sheet 2, eliminating micro gaps, and further improving the sealing performance.

[0066] In this embodiment, the upper surface of the first part 121 is flush with the upper surface of the second main body 11, and / or, the lower surface of the second part 122 is flush with the lower surface of the first main body 21. Thus, the edge portion 12 of the top cover 1 and the explosion-proof sheet 2 form a flat mating interface in the axial direction X. The flushness of the upper surface of the first part 121 with the upper surface of the second main body 11 ensures the flatness of the top of the cap 10, facilitating its installation with other battery components. The flushness of the lower surface of the second part 122 with the lower surface of the first main body 21 ensures the flatness of the bottom of the explosion-proof sheet 2, which is beneficial for the welding and assembly of the connecting aluminum sheet 3, avoiding stress concentration or poor contact caused by the stepped structure, and ensuring the overall flatness and assembly accuracy of the cap 10.

[0067] like Figure 7As shown, in a preferred embodiment, the upper surface of the covered portion 22 is higher than the upper surface of the first main body portion 21, that is, the covered portion 22 protrudes upward relative to the first main body portion 21 to form a stepped structure. This step can be embedded in the corresponding receiving space formed inside the edge portion 12 of the top cover 1, so as to achieve a tight fit between the top cover 1 and the explosion-proof sheet 2, effectively improving the bonding strength between the edge portion 12 and the covered portion 22, preventing relative displacement between the two due to vibration or impact, and further enhancing the integrity and reliability of the structure.

[0068] In a preferred embodiment, the axial X thickness of the edge portion 12 is equal to the sum of the axial X thicknesses of the first main body portion 21 and the second main body portion 11, so that after the edge portion 12 of the top cover 1 completely wraps the covered portion 22 of the explosion-proof sheet 2, the lower surface of the edge portion 12 is flush with the lower surface of the first main body portion 21 of the explosion-proof sheet 2, and the overall shoulder thickness is equal to that of the traditional semi-enclosed structure. While realizing the structural improvement of the top cover 1 wrapping the explosion-proof sheet 2, it does not increase the space occupied at the top of the battery cell, and retains the core advantage of high energy density of the semi-enclosed structure to the greatest extent.

[0069] In another embodiment, the axial X thickness of the edge portion 12 is less than the sum of the axial X thicknesses of the first main body portion 21 and the second main body portion 11, and is greater than or equal to 75% of the sum of the axial X thicknesses of the first main body portion 21 and the second main body portion 11. In this case, the lower surface of the edge portion 12 can be higher than the lower surface of the first main body portion 21, and the overall shoulder thickness is smaller than that of the conventional semi-enclosed structure, which can make the height of the core 30 higher, thereby improving the energy density of the battery.

[0070] In this embodiment, the second main body 11, the first part 121, the second part 122, and the third part 123 are integrally formed, making the top cover 1 a single complete part. This eliminates the need for separate processing of multiple parts before assembly, simplifying the manufacturing process and assembly procedures. Simultaneously, the integral forming ensures the connection strength between the parts, avoiding gaps or welding defects that may exist in separate structures, further improving the airtightness and structural reliability of the cap 10, and reducing manufacturing costs.

[0071] Furthermore, the first main body 21 and the covered part 22 are integrally formed, so that there is no connecting interface or weld between the thickness reduction area of ​​the explosion-proof sheet 2 and the main body area. The material between the two is continuous and the structure is uniform. There are no stress concentrations or weak performance areas caused by welding or connection, which ensures the consistency and reliability of the overall mechanical properties of the explosion-proof sheet 2. At the same time, the integral forming simplifies the manufacturing process of the explosion-proof sheet 2, reduces production costs, and facilitates mass production.

[0072] In this embodiment, the top cover 1 and the explosion-proof sheet 2 are stacked one on top of the other and welded together, and the weld joint 13 is as follows: Figure 5As shown. The edge portion 12 of the top cover 1 (first part 121, second part 122 and third part 123) is in direct contact with the sealing ring 5, while the explosion-proof sheet 2 is not in contact with the sealing ring 5. When the cap 10 is assembled for sealing, the assembly pressure is entirely applied directly to the top cover 1 and its edge portion 12. The assembly extrusion pressure and bending force are all borne by the top cover 1. The explosion-proof sheet 2 is completely detached from the assembly force system and is not subjected to pressure or bending throughout the entire process.

[0073] The battery cap 10 balances high energy density with mass production compatibility. The thickness of the first main body 21 is greater than or equal to the thickness of the covered part 22, the thickness of the second main body 11 is greater than the thickness of the first part 121, and the axial X thickness of the edge part 12 does not exceed the sum of the axial X thicknesses of the first main body 21 and the second main body 11. The overall height is maintained or even lower than the original shoulder height, maximizing the space for the top of the battery cell and retaining the high capacity advantage of the semi-enclosed structure. At the same time, it does not require changes to existing assembly equipment and processes, has low modification difficulty and low production cost, and can be directly adapted to existing mass production lines.

[0074] To verify the superiority of the battery cap 10 provided in this application, the applicant conducted ten tests on the caps of the embodiments and comparative examples, including initial power-off values ​​and post-assembly power-off values, to obtain the power-off value loss. The cap 10 of the embodiments employs... Figure 6 The structure in the middle, the proportional cap adopts Figure 1 The structure and data are shown in Table 1 below:

[0075] Table 1 Comparison of initial power-off value and power-off value and airtightness of the cap after assembly

[0076]

[0077] According to the data in Table 1, the average power failure value loss of the cap 10 in the embodiment is 0.054 MPa, while the average power failure value loss of the cap in the comparative example is 0.184 MPa. Thus, the power failure value loss of the embodiment is less than that of the comparative example, which proves that the cap 10 of the embodiment can better stabilize the power failure threshold of the explosion-proof sheet 2.

[0078] In addition, the caps of the embodiments and comparative examples were subjected to an airtightness test of 2.5 MPa. It was found that the NG rate of the comparative example cap was 20%, while the NG rate of the embodiment cap 10 was 0%, thus proving that the embodiment cap 10 has good airtightness and can eliminate the problem of leakage.

[0079] The battery cap 10 has a strong versatility structure. Its simple structure and reasonable design can be adapted to the full range of cylindrical lithium-ion batteries such as 18650 and 21700, and can be widely used in consumer batteries, power batteries and energy storage batteries.

[0080] like Figure 6As shown, in a preferred embodiment, the cap 10 further includes a connecting aluminum sheet 3 and an insulating ring 4. The connecting aluminum sheet 3 is disposed below the explosion-proof sheet 2, and an insulating ring 4 is provided between the periphery of the connecting aluminum sheet 3 and the explosion-proof sheet 2, thereby achieving electrical isolation and structural support between the explosion-proof sheet 2 and the connecting aluminum sheet 3, ensuring the independence of the current transmission path and the insulation reliability of each component inside the cap 10.

[0081] Based on the same concept, such as Figure 3 As shown, this embodiment of the invention also provides a battery, including the cap 10 as described in any of the above embodiments.

[0082] It should be noted that the steel casing 20, the winding core 30, and other components of the battery provided in this embodiment can be selected from any suitable existing structures. To clearly and concisely illustrate the technical solution provided in this embodiment, the above-mentioned parts will not be described in detail here. However, it should be understood that this embodiment is not limited in scope as a result.

[0083] In this embodiment, the battery embodiment corresponds to the embodiment of cap 10. It can solve the technical problems solved by the embodiment of cap 10 and achieve the technical effects of the embodiment of cap 10. The specific details will not be repeated here.

[0084] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.

[0085] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0086] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0087] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0088] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0089] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A battery cap, comprising: A top cover, an explosion-proof sheet, and a sealing ring; the top cover is connected above the explosion-proof sheet; the sealing ring is located around the top cover and the explosion-proof sheet; characterized in that: The periphery of the top cover is bent downward and then bent inward to form a rim portion, which wraps around the periphery of the explosion-proof sheet; the explosion-proof sheet includes a first main body and a covered portion located on the periphery of the first main body, which is wrapped by the rim portion. The explosion-proof sheet and the sealing ring are separated by the edge portion; the explosion-proof sheet and the sealing ring are not in contact; The edging portion includes a first portion located above the covered portion, a second portion located below the covered portion, and a third portion located around the covered portion, the third portion being connected between the first portion and the second portion; the top cover also includes a second main body portion connected to the first portion; the axial thickness of the edging portion does not exceed the sum of the axial thicknesses of the first main body portion and the second main body portion; The upper surface of the first part is flush with the upper surface of the second main body, and / or the lower surface of the second part is flush with the lower surface of the first main body.

2. The cap according to claim 1, characterized in that, The thickness of the second main body is greater than the thickness of the first part, or the thickness of the first part is 50% to 70% of the thickness of the second main body.

3. The cap according to claim 2, characterized in that, The thickness of the first part, the thickness of the second part, and the thickness of the third part are all equal; the first part, the second part, and the covered part are arranged in parallel.

4. The cap according to claim 1, characterized in that, The thickness of the first main body is greater than or equal to the thickness of the covered part, or the thickness of the covered part is 35% to 100% of the thickness of the first main body.

5. The cap according to claim 1, characterized in that, The upper surface of the covered portion is higher than the upper surface of the first main body portion.

6. The cap according to claim 1, characterized in that, The axial thickness of the edging portion is equal to the sum of the axial thicknesses of the first main body portion and the second main body portion.

7. The cap according to claim 1, characterized in that, The cap also includes a connecting aluminum sheet and an insulating ring; the connecting aluminum sheet is disposed below the explosion-proof sheet; the insulating ring is provided between the periphery of the connecting aluminum sheet and the explosion-proof sheet.

8. A battery, characterized in that, include: The cap as described in any one of claims 1-7.

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