Cover plate assembly and single cell

Abstract

The application provides a cover plate assembly and a single battery. The cover plate assembly comprises a cover plate and a pole connected to the cover plate. The cover plate comprises a cover plate body, the cover plate body comprises a first surface and a second surface arranged oppositely along a first direction. The pole comprises a first connecting part and a second connecting part along the first direction, the first connecting part and the second connecting part are connected to each other and form a connecting surface, and the materials of the first connecting part and the second connecting part are different. The first connecting part comprises a first main body part in a column shape and a first protruding part arranged circumferentially around the outer wall of the first main body part. The connecting part of the first main body part and the outer wall of the first protruding part forms a corner, and the minimum distance H5 from the corner to the connecting surface is greater than or equal to 0.1 mm. The application provides the cover plate assembly and the single battery. The weight and cost of the cover plate assembly can be effectively reduced.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a cover plate assembly and a single battery cell. Background Technology

[0002] With increasingly fierce cost competition in the lithium battery industry, the cover plate assembly of a single cell is a key component of lithium batteries, and its cost directly affects the overall cost of lithium batteries.

[0003] The cover plate assembly includes a cover plate body and an electrode post that penetrates and connects to the cover plate body. The electrode post is usually a structural component made of metal, which has a high material cost. Therefore, how to reduce the cost of the electrode post is a technical problem that urgently needs to be solved in battery technology. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a cover plate assembly and a single cell to at least partially solve the problem of high cost of the cover plate assembly.

[0005] To achieve the above objectives, a first aspect of this application provides a cover plate assembly, comprising: a cover plate, and a pole connected to the cover plate; the cover plate includes a cover plate body, the cover plate body including a first surface and a second surface disposed opposite to each other along a first direction; the pole includes a first connecting portion and a second connecting portion along the first direction, the first connecting portion and the second connecting portion being interconnected to form a connecting surface, the first connecting portion and the second connecting portion being made of different materials; the first connecting portion includes a columnar first main body portion, and a first protrusion disposed circumferentially around the outer wall of the first main body portion; the connection between the outer wall of the first main body portion and the first protrusion portion forms an angle, the minimum distance H5 from the angle to the connecting surface being 0.1 mm or more.

[0006] Optionally, the corner is rounded.

[0007] Optionally, the second connecting portion includes a columnar second main body portion and a second protrusion circumferentially disposed around the outer wall of the second main body portion; the connecting surface includes a main connecting surface and a protruding connecting surface, the main connecting surface being located between the second main body portion and the first main body portion, and the protruding connecting surface being located between the second protrusion and the first protrusion; along the first direction, the protruding connecting surface is located on the side of the main connecting surface closer to the second main body portion.

[0008] Optionally, the first main body and the second main body constitute the pole body of the pole; the end face of the pole body near the second surface along the first direction is the first end face; along the first direction, the minimum straight-line distance between the middle part of the main body connecting surface and the first end face is H1, and the minimum straight-line distance between the part of the main body connecting surface near the outer wall of the pole body and the first end face is H2, where H1 > H2.

[0009] Optionally, the main connecting surface includes an arc-shaped surface that protrudes from the center away from the first end face.

[0010] Optionally, the first main body and the second main body constitute the pole body of the pole, and the first protrusion and the second protrusion constitute the protrusion of the pole, wherein the protrusion is circumferentially arranged around the outer wall of the pole body. The volume ratio of the first protrusion to the total volume of the protrusion is at least 60%; or... The dimension of the protrusion along the first direction is H3; the end face of the pole body close to the first surface along the first direction is the second end face; the minimum straight-line distance from the protrusion along the first direction to the second end face is H4; and the ratio of H3 to H4 is less than 1.

[0011] Optionally, along the first direction, the minimum straight-line distance between the protruding connecting surface and the main connecting surface is H8, and the maximum size of the first protrusion is H9, where H9 < H8.

[0012] Optionally, the second connecting portion includes a columnar second main body portion; The minimum dimension of the first main body portion along the first direction is H6, and the minimum dimension of the second main body portion along the first direction is H7, where H6 ≤ H7; or, The projected area of ​​the first main body part along the first direction is smaller than the projected area of ​​the second main body part along the first direction.

[0013] Based on the same inventive concept, a second aspect of this application also provides a single-cell battery, including a housing, an electrode assembly, and a cover assembly as described in the first aspect. The cover assembly is connected to the housing, and the electrode assembly is disposed within the space formed by the cover assembly and the housing. The electrode post is configured as the negative electrode of the single-cell battery. The first connecting part is made of copper, and the second connecting part is made of aluminum. The electrode assembly is connected to the electrode post via an adapter piece, and the adapter piece is welded to the first connecting part.

[0014] Optionally, in the first connecting portion, the area welded to the adapter piece has a larger dimension along the first direction than the dimension along the first direction of the non-welded area.

[0015] As can be seen from the above, the cover plate assembly and single cell provided in this application are constructed into poles by using a first connecting part and a second connecting part made of different materials. This can ensure that the poles form a stable, reliable and electrically good connection with the tabs of the electrode assembly through the first connecting part, and can also form the second connecting part with a material with lower density and lower cost, thereby reducing the overall weight and cost of the poles.

[0016] Meanwhile, designing the minimum distance H5 from the corner to the connection surface to be more than 0.1 mm ensures that the first connection part has sufficient thickness to isolate the second connection part and the electrolyte, effectively preventing the electrolyte inside the single cell from passing through the first connection part and contacting the second connection part, and effectively reducing the risk of the second connection part being corroded by the electrolyte. 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 top view schematic diagram of the cover plate assembly of the first structure according to an embodiment of this application; Figure 2 for Figure 1 Partial cross-sectional diagram of section AA; Figure 3 for Figure 2 Enlarged schematic diagram of part B in the middle; Figure 4 The cover plate assembly of the second structure in the embodiments of this application is in Figure 2 Enlarged schematic diagram of part B in the middle; Figure 5 This is a partial cross-sectional schematic diagram of the pole and the sealing part in the natural state of the cover plate assembly of the second structure in this application embodiment; Figure 6 This is a partial cross-sectional schematic diagram of the pole post of the cover plate assembly of the second structure according to an embodiment of this application; Figure 7 This is a schematic diagram of a single battery cell according to an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 1000, Cover plate assembly; 100. Cover plate; 110. Cover plate body; 111. Mounting hole; 112. First surface; 113. Second surface; 1111. First end; 1112. Second end; 120. First fixing part; 130. Second fixing part; 200, pole post; 210, pole post body; 211, first end face; 212, second end face; 220, protrusion; 230, first connecting part; 231, first main body part; 232, first protrusion; 240, second connecting part; 241, second main body part; 242, second protrusion; 250, connecting surface; 251, main body connecting surface; 252, protruding connecting surface; 260, corner; 300, lower insulating component; 400, insulating part; 500, sealing part; 2000, Housing; 3000, Electrode Assembly; 4000, Adapter Plate; 5000, Solder Mark. Detailed Implementation

[0020] 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.

[0021] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0022] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[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] Figure 1 A top view schematic diagram of the cover plate assembly 1000 of the first structure is shown. Figure 2 Showing Figure 1 Partial cross-sectional diagram of section AA. Figure 3Showing Figure 2 Enlarged diagram of part B.

[0026] like Figure 1 , Figure 2 and Figure 3 In some embodiments, the cover plate assembly 1000 includes: a cover plate 100, and a pole post 200 connected to the cover plate 100; the cover plate 100 includes a cover plate body 110 and a second fixing part 130, and the cover plate 100 is provided with a direction along a first direction (e.g., Figure 3 The cover plate body (110) has a through mounting hole 111 in the Z direction. The cover plate body (110) includes a first surface (112) and a second surface (113) arranged opposite to each other in the first direction. The second fixing part 130 extends at least from the second surface 113 toward the central axis of the mounting hole 111, and the free end of the second fixing part 130 forms the second end 1112 of the mounting hole 111. The first direction is the thickness direction of the cover plate body 110.

[0027] It should be noted that the free end of the second fixing part 130 is the end of the second fixing part 130 that is away from the cover plate body 110.

[0028] For example, the second fixing part 130 and the cover plate body 110 can be connected by welding or integral molding.

[0029] like Figure 3 The portion of the second fixing part 130 near the cover plate body 110 extends from the second surface 113 in a direction away from the first surface 112, and the portion of the second fixing part 130 near its free end extends in a direction toward the central axis of the mounting hole 111. At this time, the second fixing part 130 can protrude from the second surface 113.

[0030] In addition to the structure described above, the second fixing part 130 can also extend uniformly towards the central axis of the mounting hole 111. In this case, the second fixing part 130 can be flush with the second surface 113.

[0031] For example, the pole post 200 overlaps with the projection portion of the second fixing part 130 along the first direction, so that the pole post 200 can only partially extend out of the inner hole formed by the second fixing part 130, preventing the pole post 200 from passing entirely through the inner hole formed by the second fixing part 130.

[0032] Understandably, in the cover plate assembly 1000, the end of the electrode post 200 near the second surface 113 along the first direction is electrically connected to the tab of the electrode assembly 3000, and the end near the first surface 112 is electrically connected to an external circuit (e.g., a busbar assembly or a switch). Therefore, the material selection of the electrode post 200 needs to consider its material compatibility with the tab of the electrode assembly 3000 to ensure a reliable connection between the electrode post 200 and the tab. However, if only the above factors are considered when selecting the material of the electrode post 200, it may result in excessively high material costs and excessive weight for the electrode post 200.

[0033] Taking the negative electrode post 200 (hereinafter referred to as the negative electrode post), which serves as the negative electrode of a single battery cell, as an example, the material of the negative electrode tab of the electrode assembly 3000 is copper. In order to reliably connect the negative electrode post and the negative electrode tab, the negative electrode post can be formed using only copper material. However, copper material has a high cost and high density. If the entire negative electrode post is made of copper material, it will be detrimental to both the cost and energy density of the single battery cell.

[0034] The applicant's research found that, in order to reduce the cost and weight of the electrode post 200, at least two different materials can be used to form a composite electrode post. For example, the part of the electrode post 200 that is electrically connected to the tab of the electrode assembly 3000 can be made of the same material as the tab, while the part of the electrode post 200 that is not in contact with the tab can be made of a material with lower density or unit price, so as to reduce the overall weight and cost of the electrode post 200.

[0035] Figure 4 The second type of cover plate assembly 1000 was demonstrated. Figure 2 An enlarged diagram of part B in the middle. Figure 5 A partial cross-sectional view of the pole post 200 and the sealing part 500 in their natural state is shown for the cover plate assembly 1000 of the second structure.

[0036] In view of this, such as Figure 4 and Figure 5In some embodiments, the cover plate assembly (1000) includes: a cover plate (100) and a pole post (200) connected to the cover plate (100); the cover plate (100) includes a cover plate body (110), the cover plate body (110) including a first surface (112) and a second surface (113) disposed opposite to each other along a first direction; the pole post (200) includes a first connecting portion (230) and a second connecting portion (240) along the first direction, the first connecting portion (230) and the second connecting portion (240) being connected to each other. The first connecting part (230) and the second connecting part (240) are made of different materials; the first connecting part (230) includes a columnar first main body part (231) and a first protrusion (232) arranged circumferentially around the outer wall of the first main body part (231); the connection between the outer wall of the first main body part (231) and the first protrusion (232) forms an angle (260), and the minimum distance H5 from the angle (260) to the connecting surface (250) is 0.1 mm or more.

[0037] It should be noted that the outer wall of the first main body 231 surrounds the central axis of the pole post 200 (e.g., Figure 4 (Dotted and dashed lines in the text) settings.

[0038] For example, the first main body 231 can be a cylinder with a circular cross section (unless otherwise specified, the cross section in the following description is a cross section perpendicular to the central axis of the pole post 200), or it can be a cylinder with a polygonal cross section.

[0039] For example, the outer contour shape of the cross-section of the first protrusion 232 may be the same as or different from the cross-sectional shape of the first main body 231.

[0040] For example, the first connecting part 230 and the second connecting part 240 can be connected by processes such as friction welding, casting and rolling composite, high-temperature diffusion composite or brazing composite.

[0041] For example, H5 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm.

[0042] by Figure 4 Using the structure and orientation shown as an example, the lower first connecting part 230 is used to connect to the tab of the electrode assembly 3000, and the upper second connecting part 240 is used to connect to an external circuit. The material of the first connecting part 230 can be the same as the material of the tab of the electrode assembly 3000 to ensure a reliable connection between the electrode post 200 and the tab. The material of the second connecting part 240, while ensuring connection to the external circuit, can be a material with lower density and / or lower cost, thereby reducing the overall material cost and weight of the electrode post 200.

[0043] The second connection portion 240 is at risk of being corroded by the electrolyte because it is made of a different material than the first connection portion 230 (the first connection portion 230 is made of the same material as the tab of the bare cell electrode assembly 3000, so it is not corroded by the electrolyte). If the second connection portion 240 is corroded by the electrolyte, it will not only affect the connection between the electrode post 200 and the external circuit, but may also cause the electrode post 200 to fail to compress the sealing portion 500, thereby causing the cover plate assembly 1000 to fail to seal and the electrolyte to leak out.

[0044] To address the aforementioned issues, the second connecting portion 240 can be isolated and protected by the first connecting portion 230. However, if the thickness of the first connecting portion 230 is too small, it may break during the assembly and use of the cover assembly 1000, exposing the second connecting portion 240 at the point of breakage. Electrolyte may then come into contact with the second connecting portion 240 through this breakage, leaving it at risk of corrosion.

[0045] Combination Figure 5 In the first connecting portion 230, the part with the smallest thickness is the corner 260 between the first main body portion 231 and the first protrusion 232. In order to prevent the corner 260 from being damaged due to its small thickness, this embodiment limits H5 to H5≥0.1mm, which can make the first connecting portion 230 more reliably isolate the electrolyte from the second connecting portion 240 and effectively reduce the risk of corrosion of the second connecting portion 240.

[0046] The cover plate assembly 1000 provided in this embodiment uses a first connecting part 230 and a second connecting part 240 made of different materials to form the electrode post 200. This ensures that the electrode post 200 forms a stable, reliable, and electrically effective connection with the electrode tab of the electrode assembly 3000 through the first connecting part 230. Furthermore, the second connecting part 240 can be formed using a material with lower density and cost, thereby reducing the overall weight and cost of the electrode post 200. Simultaneously, designing the minimum distance H5 from the corner (260) to the connecting surface (250) to be greater than 0.1 mm ensures that the first connecting part 230 has sufficient thickness to isolate the second connecting part 240 from the electrolyte, effectively preventing the electrolyte inside the single cell from passing through the first connecting part 230 and contacting the second connecting part 240, thus effectively reducing the risk of the second connecting part 240 being corroded by the electrolyte.

[0047] like Figure 4 and Figure 5In some embodiments, the first protrusion 232 is located on the side of the second fixing part 130 near the first surface 112, and a sealing part 500 is connected between the first protrusion 232 and the second fixing part 130; when the sealing part 500 is in its natural state, along the first direction, the orthographic projection of the sealing part 500 on the first protrusion 232 does not exceed the outer contour of the first protrusion 232.

[0048] For example, the material of the sealing portion 500 may include an elastic insulating material, such as rubber or plastic.

[0049] For example, the sealing part 500 may be disposed around the outer wall periphery of the first main body part 231, and the sealing part 500 may be fitted onto the first main body part 231.

[0050] The terminal post 200 and the cover plate 100 are sealed by the sealing part 500 to prevent the electrolyte in the single cell from leaking out.

[0051] When the sealing part 500 is connected to the pole post 200 and is in its natural state, the area in contact between the sealing part 500 and the first protrusion 232 is called the first area. For example... Figure 4 When the electrode post 200 and the second fixing part 130 cooperate to compress the sealing part 500, it is understandable that the first protrusion 232 will directly apply compressive force to the sealing part 500. Therefore, the aforementioned first region is the area where the sealing part 500 experiences greater compressive force, resulting in greater deformation and correspondingly better sealing performance. When the sealing part 500 is deformed under pressure and achieves a reliable seal, the electrolyte will at most not exceed the aforementioned first region. That is, even if the electrolyte enters between the sealing part 500 and the electrode post 200, it will only contact the first connecting part 230 and will not contact the second connecting part 240 along the sealing part 500. This ensures that the second connecting part 240 will not be corroded by the electrolyte.

[0052] like Figure 4 and Figure 5 In some embodiments, the 260° angle is rounded.

[0053] If the corner 260 is a right angle, the thickness of the first connecting portion 230 at that right angle will be too small, meaning the minimum distance from the corner 260 to the connecting surface 250 will be too small. During the assembly and use of the electrode post 200, this right angle is prone to damage, exposing the second connecting portion 240 at the damaged point. Electrolyte may come into contact with the second connecting portion 240 through this damaged point, and the second connecting portion 240 will still be at risk of corrosion.

[0054] To avoid the aforementioned problems, this embodiment sets the corner 260 as a rounded corner. Compared to the aforementioned right-angle structure, the rounded corner structure can have a filling effect, effectively increasing the thickness at this location, making it easier for H5 to meet process requirements, and more reliably isolating the electrolyte from the second connection part 240, effectively reducing the risk of corrosion of the second connection part 240.

[0055] Meanwhile, setting the corner 260 as a rounded corner is more conducive to the demolding of the pole post 200 from the molding die, which helps to reduce the manufacturing difficulty of the pole post 200.

[0056] like Figure 4 In some embodiments, the cover plate 100 further includes a first fixing part 120, which extends from the first surface 112 in a first direction away from the cover plate body 110, and the free end of the first fixing part 120 forms the first end 1111 of the mounting hole 111; along the first direction, the first protrusion 232 is located between the first fixing part 120 and the second fixing part 130.

[0057] It should be noted that the free end of the first fixing part 120 is the end of the first fixing part 120 that is away from the cover plate body 110. The shape of the inner hole formed by the first fixing part 120 and the inner hole formed by the second fixing part 130 can be circular or polygonal, and is not limited here.

[0058] For example, such as Figure 4 The portion of the first fixing part 120 near the cover plate body 110 extends from the first surface 112 in a first direction away from the cover plate body 110, and the portion of the first fixing part 120 near its free end extends in the direction of the central axis of the mounting hole 111.

[0059] Of course, the first fixing part 120 may also extend only from the first surface 112 in the first direction away from the cover plate body 110.

[0060] For example, the first fixing part 120 and the cover plate body 110 can be connected by welding or integral molding. The connection method between the first fixing part 120 and the cover plate body 110 can be the same as or different from the connection method between the second fixing part 130 and the cover plate body 110.

[0061] In addition to the connection methods described above, the first fixing part 120 and the second fixing part 130 can be connected by welding or integral molding to form a structural component, which is connected to the cover plate body 110 by welding or integral molding.

[0062] For example, along the first direction, the second surface 113 may be connected to the lower insulating member 300.

[0063] For example, the projections of the first fixing part 120 and the pole post 200 along the first direction do not overlap, so that the pole post 200 can pass through the inner hole formed by the first fixing part 120.

[0064] The first protrusion 232 and the sealing part 500 are located within the space defined by the first fixing part 120 and the second fixing part 130, which can limit the pole post 200 and the sealing part 500 to a certain extent, so that the sealing part 500 and the second fixing part 130 can be located in a preset relative position, which helps to prevent the sealing part 500 and the second fixing part 130 from shifting, and helps the sealing part 500 to maintain a good sealing effect.

[0065] like Figure 4 In some embodiments, the cover plate assembly 1000 further includes an insulating portion 400, which is at least connected between the first fixing portion 120 and the pole post 200.

[0066] For example, the insulating portion 400 can be formed by injection molding.

[0067] For example, the insulating portion 400 may be located only within the mounting hole 111, or it may extend outward and cover the first fixing portion 120.

[0068] When assembling the cover plate assembly 1000 of this embodiment, the pole post 200, to which the sealing part 500 is connected, is inserted into the mounting hole 111, and the sealing part 500 is compressed by the pole post 200, causing the sealing part 500 to deform under pressure and achieve a sealing effect. Afterwards, the first fixing part 120 and the pole post 200 can be connected by the insulating part 400 to achieve relative fixation between the pole post 200 and the cover plate 100, forming a reliable connection. At this time, the sealing part 500 remains in a state of compression deformation to achieve a stable and reliable sealing effect.

[0069] Meanwhile, by connecting the cover plate 100 and the pole post 200 through the insulating part 400, the amount of metal material used in the cover plate assembly 1000 as a whole can be reduced, thereby reducing material costs and weight, which is beneficial for mass production.

[0070] Figure 6 A partial cross-sectional view of the pole post 200 of the cover plate assembly 1000 of the second structure is shown.

[0071] like Figure 4 , Figure 5 and Figure 6In some embodiments, the second connecting portion 240 includes a columnar second main body portion 241 and a second protrusion 242 circumferentially disposed around the outer wall of the second main body portion 241; the connecting surface (250) includes a main connecting surface (251) and a protruding connecting surface (252), the main connecting surface (251) being located between the second main body portion (241) and the first main body portion (231), and the protruding connecting surface (252) being located between the second protrusion (242) and the first protrusion (232); along a first direction, the protruding connecting surface 252 is located on the side of the main connecting surface 251 closer to the second main body portion 241.

[0072] For example, the main connecting surface 251 and the protruding connecting surface 252 form a smoothly transitioned arc surface or stepped surface.

[0073] Combination Figure 5 Taking the structure and orientation shown as an example, compared to the protruding connecting surface 252 and the main connecting surface 251 being flush along the first direction, when the main connecting surface 251 is located below the protruding connecting surface 252, it can be understood as further reducing the volume ratio of the first main body portion 231 in the pole post 200, and the reduced portion of the first main body portion 231 can be supplemented by the second main body portion 241. Since the second main body portion 241 can be formed using materials with lower cost and density, reducing the first main body portion 231 and correspondingly increasing the second main body portion 241 can effectively reduce the overall material cost and weight of the pole post 200.

[0074] Meanwhile, the main connecting surface 251 and the protruding connecting surface 252 form a structure with a height difference, which means that the first connecting part 230 and the second connecting part 240 can fit into each other, which helps to improve the connection strength of the first connecting part 230 and the second connecting part 240, prevent the connection failure of the first connecting part 230 and the second connecting part 240, and ensure the reliability of the connection between the single battery and the external circuit.

[0075] like Figure 4 and Figure 5 In some embodiments, the first main body portion 231 and the second main body portion 241 are configured as the pole body 210 of the pole 200; the end face of the pole body 210 close to the second surface (113) along the first direction is the first end face 211; along the first direction, the minimum straight distance between the middle part of the main body connecting surface 251 and the first end face 211 is H1, and the minimum straight distance between the part of the main body connecting surface 251 close to the outer wall of the pole body 210 and the first end face 211 is H2, where H1 > H2.

[0076] For example, the first end face 211 can be directly or indirectly electrically connected to the tab of the electrode assembly 3000.

[0077] Understandably, in order to achieve electrical connection between the electrode assembly 3000 and the electrode post 200, the tabs of the electrode assembly 3000 will be directly welded to the first end face 211. The welding position will be concentrated in the middle of the first end face 211. In other words, when welding the electrode post 200, the middle of the first end face 211 receives a larger amount of welding heat.

[0078] If H1 is too small, the middle part of the first main body 231 may be welded through when welding the terminal 200, which will have an adverse effect on the electrical performance of the terminal 200 and the safety performance of the single cell. At the same time, the second connection part 240 is also more susceptible to corrosion by electrolyte.

[0079] To avoid the above problems, in this embodiment, H1 is designed to be H1 > H2, so as to increase the thickness of the position in the first main body 231 used for welding with the electrode tab, reduce the risk of the first main body 231 being welded through, help to ensure the electrical performance of the electrode post 200, improve the safety performance of the single cell, and at the same time, help to reduce the risk of the second connection part 240 being corroded by the electrolyte.

[0080] like Figure 5 In some embodiments, the main connecting surface 251 includes an arcuate surface that protrudes from the center away from the first end face 211.

[0081] If the main connecting surface 251 has sharp edges, there may be a large stress concentration at the sharp edges, which may lead to cracks inside the pole post 200, which will have an adverse effect on the structural strength and electrical performance of the pole post 200.

[0082] To avoid the above problems, this embodiment designs the main connecting surface 251 to include an arc-shaped surface, which can prevent large stress concentration inside the pole post 200, reduce the risk of cracks inside the pole post 200, and help ensure the structural strength and electrical performance of the pole post 200.

[0083] like Figure 4 and Figure 5 In some embodiments, the first main body portion 231 and the second main body portion 241 are configured as the pole body 210 of the pole 200, and the first protrusion 232 and the second protrusion 242 are configured as the protrusion 220 of the pole 200. The protrusion 220 is circumferentially arranged around the outer wall of the pole body 210; the volume ratio of the first protrusion 232 to the volume of the protrusion 220 is at least 60%.

[0084] Combining the foregoing content and Figure 4It can be seen that when the sealing part 500 is compressed by the pole post 200, the protrusion 220 is the main part that applies the compressive force to the sealing part 500. If the structural strength of the protrusion 220 is low, then when the sealing part 500 is compressed, the protrusion 220 may deform under the elastic force of the sealing part 500, or even cracks may appear at the connection between the protrusion 220 and the pole post body 210.

[0085] Understandably, the material density of the first connecting portion 230 is relatively high, and correspondingly, its structural strength is also relatively high. In this embodiment, the volume ratio of the first protrusion 232 to the volume of the protrusion 220 is designed to be greater than or equal to 60%. By increasing the material proportion of the first connecting portion 230 in the protrusion 220, the structural strength of the protrusion 220 can be effectively improved, so as to ensure that the protrusion 220 can provide a stable and reliable compressive force to the sealing portion 500, and ensure that the sealing portion 500 can achieve a better sealing effect.

[0086] like Figure 4 and Figure 5 In some embodiments, the protrusion 220 has a dimension of H3 along the first direction; the end face of the pole body 210 close to the first surface (112) along the first direction is the second end face 212, the minimum straight distance from the protrusion 220 to the second end face 212 along the first direction is H4, and the ratio of H3 to H4 is less than 1.

[0087] For example, the ratio of H3 to H4 can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.7, 0.8 or 0.9.

[0088] For example, H3 can be 0.5mm to 1.5mm.

[0089] For example, H4 can be 2.5mm to 3.5mm.

[0090] If the ratio of H3 to H4 is too small, one possibility is that the thickness of the protrusion 220 (i.e., H3) is too small, resulting in low structural strength of the protrusion 220. Another possibility is that the height of the portion of the electrode body 210 above the protrusion 220 (i.e., H4) is too large, resulting in an excessively large extension of the electrode body 210 beyond the cover plate 100, occupying too much space in the height direction of the individual cells. When the individual cells are assembled into a battery pack, this will occupy a large amount of space within the battery pack, leading to a lower energy density. If the ratio of H3 to H4 is too large, it indicates that the height of the portion of the electrode body 210 above the protrusion 220 is too small, which may result in an insufficient extension of the electrode body 210 beyond the cover plate 100. When the electrode 200 is connected to the external circuit, the external circuit may interfere with the insulation portion 400, adversely affecting the reliability of the connection between the electrode 200 and the external circuit.

[0091] To avoid the aforementioned problems, this embodiment designs the ratio of H3 to H4 to be less than 1, which ensures the structural strength of the protrusion 220. Simultaneously, it allows for a suitable height for the electrode post body 210 extending beyond the cover plate 100, ensuring a reliable connection between the electrode post 200 and the external circuit, while also reducing the space occupied by individual cells within the battery pack and contributing to increased energy density.

[0092] like Figure 6 In some embodiments, the minimum dimension of the first main body portion 231 along the first direction is H6, and the minimum dimension of the second main body portion 241 along the first direction is H7, where H6 ≤ H7.

[0093] For example, both H6 and H7 are greater than 1 mm. If H6 is too small, it may penetrate the first main body 231 when the electrode post 200 is welded to the tab of the electrode assembly 3000, causing the connection between the electrode post 200 and the electrode assembly 3000 to fail, and also increasing the risk of corrosion of the second connection part 240. If H7 is too small, it may penetrate the second main body 241 when the electrode post 200 is welded to the external circuit, causing the connection between the electrode post 200 and the external circuit to fail. Therefore, H6 and H7 can be designed to be greater than 1 mm, which can effectively prevent the first main body 231 or the second main body 241 from being welded through, ensuring the connection reliability of the electrode post 200, the electrode assembly 3000 and the external circuit, and further preventing the second connection part 240 from being corroded.

[0094] Based on the foregoing, it can be seen that the material of the second connecting part 240 has a lower material cost and lower density. If H6 > H7, then the effect of reducing the overall material cost and weight of the pole post 200 by setting the second connecting part 240 is not significant.

[0095] Therefore, in this embodiment, H6 and H7 are limited to H6≤H7, which can effectively reduce the overall material cost and weight of the pole post 200.

[0096] like Figure 4 and Figure 6 In some embodiments, along the first direction, the minimum straight-line distance between the protruding connecting surface 252 and the main connecting surface 251 is H8, and the maximum size of the first protrusion 232 is H9, where H9 < H8.

[0097] For example, H8 < 2 mm.

[0098] If H9 > H8, it means that the interlocking depth between the first main body 231 and the second main body 241 is too small, which will result in a low connection strength between the first connecting part 230 and the second connecting part 240, which may cause the pole post 200 to fail.

[0099] To avoid the above problems, in this embodiment, H9 and H8 are designed to be H9 < H8, which helps to improve the connection strength between the first connecting part 230 and the second connecting part 240 and ensure the electrical performance of the pole 200.

[0100] like Figure 6 In some embodiments, the projected area of ​​the first main body portion 231 along the first direction is smaller than the projected area of ​​the second main body portion 241 along the first direction.

[0101] Taking the example that both the first main body 231 and the second main body 241 are cylindrical structures, the outer diameter of the first main body 231 is D1, and the outer diameter of the second main body 241 is D2, where D2 > D1.

[0102] When the outer wall of the first protrusion 232 is flush with the outer wall of the second protrusion 242, designing D1 to be smaller helps to increase the area of ​​the bottom surface of the first protrusion 232, thereby making the contact area between the first protrusion 232 and the sealing part 500 larger, which helps to improve the sealing performance of the sealing part 500.

[0103] Meanwhile, because the material of the second connection part 240 has low material cost and low density, designing D2 to be larger helps to reduce the overall material cost and weight of the terminal 200. It also helps to improve the reliability of the connection between the terminal 200 and the external circuit.

[0104] Based on the same inventive concept and in conjunction with the description of the cover plate assembly 1000 in the above embodiments, this embodiment provides a single battery cell that has the corresponding technical effects of the cover plate assembly 1000 in the above embodiments, which will not be repeated here.

[0105] Figure 7 A schematic diagram of a single battery cell is shown.

[0106] like Figure 4 and Figure 7 A single battery includes a housing 2000, an electrode assembly 3000, and a cover assembly 1000 as described in the above embodiments. The cover assembly 1000 is connected to the housing 2000, and the electrode assembly 3000 is disposed within the space formed by the cover assembly 1000 and the housing 2000. The electrode post 200 is configured as the negative electrode of the single battery. The first connecting part 230 is made of copper, and the second connecting part 240 is made of aluminum. The electrode assembly (3000) is connected to the electrode post (200) through an adapter piece (4000), and the adapter piece (4000) is welded to the first connecting part (230).

[0107] It should be noted that the end of the pole post 200 of the cover plate assembly 1000 that is close to the electrode assembly 3000 can be exposed in the space where the electrode assembly 3000 is located, so that the pole post 200 and the tab of the electrode assembly 3000 can be electrically connected.

[0108] It should be noted that the adapter piece (4000) can be a sheet structure, with one part of its area being welded to the tab of the electrode assembly 3000 and another part being welded to the electrode post 200. Specifically, one side surface of the adapter piece 4000 is attached to the first connecting part 230 of the electrode post 200, while the opposite side surface forms a solder mark 5000 after welding.

[0109] When the terminal post 200 is configured as the negative electrode of a single cell, the first connection portion 230 is made of copper to ensure reliable connection between the first connection portion 230 and the negative electrode tab of the electrode assembly 3000 formed of copper foil via the adapter piece 4000. The second connection portion 240 is made of aluminum to reduce the material cost and weight of the second connection portion 240, thereby reducing the overall material cost and weight of the terminal post 200.

[0110] like Figure 4 In some embodiments, in the first connection portion (230), the area welded to the adapter piece (4000) has a larger dimension along the first direction than the dimension along the first direction of the non-welded area.

[0111] It should be noted that in the first connecting part 230, the welding area is the area covered by the solder mark 5000, while the non-welding area is the area not covered by the solder mark 5000.

[0112] As described above, when the adapter piece (4000) is welded to the first connecting portion 230, the welding area receives a larger amount of welding heat, while the non-welding area receives relatively less. To prevent the first connecting portion 230 in the welding area from being welded through, this embodiment designs the welding area to be larger in the first direction, i.e., the thickness of this area is larger. Meanwhile, for the non-welding areas with a lower risk of being welded through, their thickness is designed to be smaller, thereby reducing the volume ratio of the first connecting portion 230 in the pole post 200, which helps to reduce the overall weight and cost of the pole post 200.

[0113] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0114] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0115] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0116] 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 is limited to these examples; under the concept 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 embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0117] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0118] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. 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 plate assembly, characterized in that, include: A cover plate, and a pole connected to the cover plate; the cover plate includes a cover plate body, the cover plate body including a first surface and a second surface disposed opposite to each other along a first direction; The pole post includes a first connecting portion and a second connecting portion along the first direction. The first connecting portion and the second connecting portion are connected to each other to form a connecting surface. The first connecting portion and the second connecting portion are made of different materials. The first connecting portion includes a columnar first main body portion and a first protrusion circumferentially arranged around the outer wall of the first main body portion. The first main body and the outer wall of the first protrusion form an angle at the connection point, and the minimum distance H5 from the angle to the connection surface is 0.1 mm or more.

2. The cover plate assembly according to claim 1, characterized in that, The corners are rounded.

3. The cover plate assembly according to claim 1, characterized in that, The second connecting portion includes a columnar second main body portion and a second protrusion circumferentially arranged around the outer wall of the second main body portion; the connecting surface includes a main connecting surface and a protruding connecting surface, the main connecting surface being located between the second main body portion and the first main body portion, and the protruding connecting surface being located between the second protrusion and the first protrusion; Along the first direction, the protruding connecting surface is located on the side of the main body connecting surface closer to the second main body portion.

4. The cover plate assembly according to claim 3, characterized in that, The first main body and the second main body constitute the pole body of the pole; the end face of the pole body near the second surface along the first direction is the first end face; along the first direction, the minimum straight-line distance between the middle part of the main body connecting surface and the first end face is H1, and the minimum straight-line distance between the part of the main body connecting surface near the outer wall of the pole body and the first end face is H2, where H1 > H2.

5. The cover plate assembly according to claim 4, characterized in that, The main connecting surface includes an arc-shaped surface that protrudes from the center away from the first end face.

6. The cover plate assembly according to claim 3, characterized in that, The first main body and the second main body constitute the pole body of the pole, and the first protrusion and the second protrusion constitute the protrusion of the pole, the protrusion being arranged circumferentially around the outer wall of the pole body; The volume ratio of the first protrusion to the total volume of the protrusion is at least 60%; or... The dimension of the protrusion along the first direction is H3; the end face of the pole body close to the first surface along the first direction is the second end face; the minimum straight-line distance from the protrusion along the first direction to the second end face is H4; and the ratio of H3 to H4 is less than 1.

7. The cover plate assembly according to claim 1, characterized in that, Along the first direction, the minimum straight-line distance between the protruding connecting surface and the main connecting surface is H8, and the maximum size of the first protrusion is H9, where H9 < H8.

8. The cover plate assembly according to claim 1, characterized in that, The second connecting portion includes a columnar second main body portion; The minimum dimension of the first main body portion along the first direction is H6, and the minimum dimension of the second main body portion along the first direction is H7, where H6 ≤ H7; or, The projected area of ​​the first main body part along the first direction is smaller than the projected area of ​​the second main body part along the first direction.

9. A single-cell battery, characterized in that, The device includes a housing, an electrode assembly, and a cover plate assembly as described in any one of claims 1 to 8, wherein the cover plate assembly is connected to the housing, and the electrode assembly is disposed within the space formed by the cover plate assembly and the housing; the electrode post is configured as the negative electrode of the single cell, the first connecting part is made of copper, the second connecting part is made of aluminum, the electrode assembly is connected to the electrode post via an adapter piece, and the adapter piece is welded to the first connecting part.

10. The single-cell battery according to claim 9, characterized in that, In the first connecting portion, the area welded to the adapter piece has a larger dimension along the first direction than the dimension along the first direction of the non-welded area.

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