Battery monomer and battery pack

Abstract

The utility model discloses a single battery and a battery pack. The single battery comprises a shell, a battery cell and a top cover assembly, a containing cavity is formed in the shell, the battery cell is arranged in the containing cavity, and the containing cavity is provided with a cavity opening; the top cover assembly comprises a cover body and lower plastic, the cover body is arranged at the cavity opening and connected with the shell, and the lower plastic is arranged on the side, facing the containing cavity, of the cover body. A counter bore is formed in the side, facing the lower plastic, of the cover body, a connecting column is arranged on the side, facing the cover body, of the lower plastic, and at least part of the connecting column extends into the counter bore. The counter bore is provided with an opening and a bottom wall which are oppositely arranged, and the end face of the side, facing the bottom wall, of the connecting column or the bottom wall is provided with a concave-convex structure. According to the top cover assembly structure, ultrasonic energy can be more concentrated during ultrasonic welding, so that the connecting strength of the lower plastic and the top cover piece can be improved, meanwhile, the top cover assembly structure is simple in processing technology and more compact in structure, and the space utilization rate of a battery can be improved.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a battery cell and a battery pack. Background Technology

[0002] With environmental issues becoming increasingly prominent, the low-carbon economy has become the mainstream of future economic development, and new energy sources will gradually replace traditional polluting energy sources. As a representative of new energy, power batteries have gradually gained widespread application and attention.

[0003] The top cover assembly of the power battery consists of a top cover sheet and a lower plastic sheet. The top cover sheet and the lower plastic sheet need to be connected and fixed together. Currently, the top cover sheet and the lower plastic sheet are mainly fixed by combining multiple parts, which makes the assembly process of the lower plastic sheet complicated, with low production efficiency and high assembly cost. Utility Model Content

[0004] This application aims to provide a battery cell and battery pack that can solve the problems of complex assembly process, low production efficiency and high assembly cost of top cover components in existing batteries.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application propose a battery cell, comprising: a casing, a battery cell, and a top cover assembly; the casing has a receiving cavity, the battery cell is disposed within the receiving cavity, and the receiving cavity has an opening;

[0007] The top cover assembly includes a cover body and a lower plastic part. The cover body is located at the cavity opening and connected to the housing. The lower plastic part is located on the side of the cover body facing the receiving cavity. The side of the cover body facing the lower plastic part has a countersunk hole, and the side of the lower plastic part facing the cover body has a connecting post. The connecting post extends at least partially into the countersunk hole. The countersunk hole has an opening and a bottom wall that are arranged opposite to each other. The end face of the connecting post facing the bottom wall or the bottom wall has a concave-convex structure.

[0008] Optionally, the countersunk hole also has a sidewall, which is disposed between the opening and the bottom wall, and the sidewall has a protrusion protruding into the countersunk hole; along the thickness direction of the cover, a gap is formed between the protrusion and the bottom wall, and the connecting post is at least partially embedded in the gap.

[0009] Optionally, the surface roughness of the bottom wall is greater than or equal to 1.6 μm;

[0010] And / or, the surface roughness of the end face of the connecting post facing the bottom wall is greater than or equal to 1.6 μm.

[0011] Optionally, the bottom wall is a plane, and at least a portion of the bottom wall protrudes toward the countersunk hole to form the concave-convex structure;

[0012] Alternatively, at least a portion of the bottom wall may be recessed away from the cover to form the irregular structure.

[0013] Optionally, the bottom wall protrudes from the edge to the center toward the cover.

[0014] Optionally, along the thickness direction of the cover, the height difference between the center and the edge of the bottom wall is H; along the radial direction of the countersunk hole, the distance between the center and the edge of the bottom wall is L, satisfying: 1≤L / H≤10.

[0015] Optionally, along the thickness direction of the cover, the height difference H between the center and the edge of the bottom wall satisfies: 0.05mm ≤ H ≤ 0.5mm;

[0016] And / or, along the radial direction of the countersunk hole, the distance L between the center and the edge of the bottom wall satisfies: 0.5mm≤L≤5mm.

[0017] Optionally, the bottom wall is further provided with a plurality of flow guide grooves, and the connecting column is at least partially embedded in the flow guide grooves;

[0018] Optionally, the battery cell must satisfy at least one of the following conditions:

[0019] A. The multiple guide channels are radially distributed around the center of the bottom wall;

[0020] B. The multiple guide channels are staggered;

[0021] C. The flow channel extends from the center of the bottom wall to the edge, and the flow cross-sectional area of ​​the flow channel increases from the center of the bottom wall to the edge.

[0022] D. A boss is provided at the center of the bottom wall.

[0023] Secondly, embodiments of this application propose a battery pack comprising the battery cells described in the first aspect.

[0024] In the embodiments of this application, the battery cell is disposed in the receiving cavity of the housing, and the top cover assembly seals the opening of the receiving cavity. The top cover assembly includes a cover body and a lower plastic sheet. A connecting post is provided on the lower plastic sheet, and a countersunk hole is provided in the cover body. The connecting post extends at least partially into the countersunk hole, and ultrasonic welding can be used to connect and fix the connecting post to the cover body within the countersunk hole. Furthermore, by providing a concave-convex structure on the end face of the connecting post, or by providing a concave-convex structure on the bottom wall of the countersunk hole, the ultrasonic energy can be more concentrated during ultrasonic welding, allowing the hot melt post to melt quickly and fill the countersunk hole. This improves the hot melt efficiency and connection strength between the lower plastic sheet and the top cover sheet, preventing the lower plastic sheet from detaching from the top cover sheet. At the same time, the top cover assembly structure of this application not only simplifies the manufacturing process but also makes the structure more compact, helping to improve the space utilization of the battery.

[0025] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein:

[0027] Figure 1 This is a schematic diagram of a battery cell according to an embodiment of this application;

[0028] Figure 2 This is an assembly diagram of the top cover assembly according to an embodiment of this application;

[0029] Figure 3 yes Figure 2 The center circle shows an enlarged view of part A;

[0030] Figure 4 This is an exploded view of the assembly structure of the top cover assembly according to an embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the cover according to an embodiment of this application;

[0032] Figure 6 This is a cross-sectional view of the cover according to an embodiment of this application;

[0033] Figure 7 yes Figure 5 The center circle shows an enlarged view of the first structure at part B;

[0034] Figure 8 yes Figure 6 The center circle shows an enlarged view of the first structure at part C;

[0035] Figure 9 yes Figure 5 The center circle shows an enlarged view of the second structure at part B;

[0036] Figure 10 yes Figure 6 The center circle shows an enlarged view of the second structure at part C;

[0037] Figure 11 yes Figure 5 The center circle shows an enlarged view of the third structure at part B;

[0038] Figure 12 yes Figure 6 The center circle shows an enlarged view of the third structure at part C;

[0039] Figure 13 yes Figure 5 The center circle shows an enlarged view of the fourth structure at part B;

[0040] Figure 14 yes Figure 6 The center circle shows an enlarged view of the fourth structure at part C;

[0041] Figure 15 yes Figure 6 The center circle shows an enlarged view of the fifth structure at section C;

[0042] Figure 16 yes Figure 5 The center circle shows an enlarged view of the sixth structure at part B;

[0043] Figure 17 yes Figure 6 The center circle shows an enlarged view of the sixth structure at part C;

[0044] Figure 18 This is a schematic diagram of the lower plastic according to an embodiment of this application;

[0045] Figure 19 yes Figure 18 A magnified view of a structure at part D, shown in the middle circle;

[0046] Figure 20 yes Figure 18 The center circle shows an enlarged view of another structure at part D;

[0047] Figure 21 yes Figure 18 The middle circle shows an enlarged view of another structure at part D.

[0048] Figure label:

[0049] 10: Housing; 101: Receiving cavity; 20: Battery cell; 30: Top cover assembly; 31: Cover body; 310: Countersunk hole; 311: Opening; 312: Bottom wall; 313: Side wall; 30a: Concave-convex structure; 314: Boss; 315: Guide groove; 316: Protrusion; 317: Gap; 32: Lower plastic; 321: Connecting post; X: Thickness direction of top cover; Y: Radial direction of countersunk hole; 40: Hot melt equipment. Detailed Implementation

[0050] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0051] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0052] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0053] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0054] The battery cell and battery pack provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0055] like Figures 1 to 4 As shown, a battery cell according to some embodiments of this application includes: a housing 10, a battery cell 20, and a top cover assembly 30; the housing 10 has a receiving cavity 101, the battery cell 20 is disposed in the receiving cavity 101, and the receiving cavity 101 has an opening; the top cover assembly 30 includes a cover body 31 and a lower plastic 32, the cover body 31 is disposed at the opening and connected to the housing 10, and the lower plastic 32 is disposed on the side of the cover body 31 facing the receiving cavity 101; the side of the cover body 31 facing the lower plastic 32 has a countersunk hole 310, and the side of the lower plastic 32 facing the cover body 31 has a connecting post 321, the connecting post 321 at least partially extending into the countersunk hole 310; the countersunk hole 310 has an opening 311 and a bottom wall 312 disposed opposite to each other, and the end face of the connecting post 321 facing the bottom wall 312 and / or the bottom wall 312 has a concave-convex structure 30a.

[0056] In this embodiment, the battery cell 20 is disposed in the receiving cavity 101 of the housing 10, and the top cover assembly 30 covers the opening of the receiving cavity 101. The top cover assembly 30 includes a cover body 31 and a lower plastic 32. A connecting post 321 is provided on the lower plastic 32, and a countersunk hole 310 is provided in the cover body 31. The connecting post 321 extends at least partially into the countersunk hole 310. The connecting post 321 can be connected and fixed to the cover body 31 in the countersunk hole 310 by ultrasonic welding. Furthermore, by providing a concave-convex structure 30a on the end face of the connecting post 321, or by providing a concave-convex structure 30a on the bottom wall 312 of the countersunk hole 310, the ultrasonic energy can be more concentrated during ultrasonic welding, so that the hot melt post can melt quickly and fill the countersunk hole 310. This improves the heat-fusion efficiency and connection strength between the lower plastic 32 and the top cover sheet, preventing the lower plastic 32 from separating from the top cover sheet. At the same time, the top cover assembly 30 structure of this application not only simplifies the processing technology but also makes the structure more compact, which helps to improve the space utilization of the battery.

[0057] Specifically, the lower plastic 32 is located on the side of the cover 31 facing the receiving cavity 101, serving as insulation between the cover 31 and the battery cell 20, preventing electrolyte corrosion of the cover 31 and thus battery failure. The lower plastic 32 can be made of thermoplastic material, and a connecting post 321 is provided on the side of the lower plastic 32 facing the cover 31. Correspondingly, a countersunk hole 310 is provided on the side of the cover 31 facing the lower plastic 32. Figures 2 to 4 As shown, when assembling the battery, the connecting post 321 of the lower plastic 32 is aligned with the countersunk hole 310 in the cover 31, and then the lower plastic 32 is fastened to the cover 31. Then, the connecting post 321 is melted by ultrasonic welding. The melted connecting post 321 fills the countersunk hole 310 and combines with the cover 31, thus realizing the connection and fixation of the lower plastic 32 and the cover 31.

[0058] Furthermore, such as Figures 5 to 14 As shown, a concave-convex structure 30a can be provided on the bottom wall 312 of the countersunk hole 310 in the cover body 31. The cover body 31 can be made of metal material. By providing the concave-convex structure 30a on the bottom wall 312 of the countersunk hole 310, the surface roughness of the bottom wall 312 can be increased. In turn, during the ultrasonic heat melting process, the melting efficiency of the connecting post 321 can be further improved, so that the connecting post 321 can be melted quickly and fill the countersunk hole 310.

[0059] Or, as Figures 18 to 21 As shown, a concave-convex structure 30a can be provided on the end face of the connecting post 321 facing the bottom wall 312 of the countersunk hole 310. During the ultrasonic heat melting process, the protrusions in the concave-convex structure 30a contact the bottom wall 312, thereby concentrating the ultrasonic energy at the protrusions, enabling the heat-melting post to quickly and fully melt and fill the countersunk hole 310 of the cover 31. It should be understood that the concave-convex structure 30a on the end face of the connecting post 321 in this application is provided before heat melting. After the connecting post 321 is heat-melted, the concave-convex structure 30a may be partially retained or may be completely melted to form a filling structure adapted to the countersunk hole 310.

[0060] Of course, a concave-convex structure 30a can also be provided on the end face of the connecting post 321 and the bottom wall 312 of the countersunk hole 310 to further improve the melting efficiency of the connecting post 321. The specific setting of the concave-convex structure 30a can be flexibly set according to actual needs and is not limited here.

[0061] In some embodiments, the lower plastic 32 and the connecting post 321 can be designed as an integrally molded structure. The integral structure helps to improve the connection strength between the connecting post 321 and the lower plastic 32, reduces the risk of the connecting post 321 falling off before installation, and also improves the efficiency of battery assembly.

[0062] Of course, the lower plastic 32 and the connecting post 321 can also be designed as separate structures, that is, the lower plastic 32 and the connecting post 321 can be processed and molded separately, and then the connecting post 321 can be heat-fused or glued to the lower plastic 32. Adopting a separate structure facilitates flexible assembly of the connection structure of the lower plastic 32 and the connecting post 321, making it more flexible in use.

[0063] In some embodiments, such as Figures 7 to 10As shown, the bottom wall 312 is planar, and at least a portion of the bottom wall 312 protrudes into the countersunk hole 310 to form an uneven structure 30a. By making the bottom wall 312 at least a portion protrude into the countersunk hole 310 to form an uneven structure 30a, the surface roughness of the bottom wall 312 is increased, and the ultrasonic welding energy is also concentrated on the protrusion formed by the bottom wall 312, thereby enabling the connecting post 321 in contact with the bottom wall 312 to be rapidly heat-melted, and improving the connection strength between the connecting post 321 and the cover 31.

[0064] In other embodiments, such as Figure 11 and Figure 12 As shown, the bottom wall 312 is planar, and at least a portion of the bottom wall 312 is recessed in the direction away from the cover 31 to form an uneven structure 30a. By making at least a portion of the bottom wall 312 recessed inward to form the uneven structure 30a, the non-recessed portion of the bottom wall 312 forms a convex shape. This increases the surface roughness of the bottom and also concentrates the ultrasonic welding energy on the convex structure of the bottom wall 312, thereby enabling the connecting post 321 in contact with the bottom wall 312 to be rapidly heat-melted.

[0065] Alternatively, the surface roughness of the bottom wall 312 can be increased, for example, by... Figure 13 and Figure 14 As shown, an embossed or frosted textured structure is formed in the bottom wall 312 to improve the welding effect between the bottom wall 312 and the connecting column 321. Of course, the protruding structure formed in the bottom wall 312 is not limited to the structure of the above embodiment, and can be flexibly set according to actual needs, and is not limited here.

[0066] It is understandable that, such as Figures 18 to 21 As shown, the concave and convex structure provided on the bottom wall 312 can also be provided on the end face of the connecting column 321 facing the bottom wall 312. The concave and convex structure provided on the end face of the connecting column 321 can be implemented with reference to the structure of the bottom wall 312 described above, and will not be described again here.

[0067] In some embodiments, the surface roughness of the bottom wall 312 is greater than or equal to 1.6 μm. For example, the surface roughness of the bottom wall 312 can be set to: 1.6 μm, 3.2 μm, 6.3 μm, 12.5 μm, 25 μm, etc. In this application, by providing a concave-convex structure 30a on the bottom wall 312 and making the surface roughness of the bottom wall 312 greater than or equal to 1.6 μm, the friction between the bottom wall 312 and the contact surface of the connecting post 321 is increased, thereby improving the hot-melt welding effect between the connecting post 321 and the cover 31.

[0068] In other embodiments, the surface roughness of the end face of the connecting post 321 facing the bottom wall 312 is greater than or equal to 1.6 μm. For example, the surface roughness of the end face of the connecting post 321 facing the bottom wall 312 can be set to: 1.6 μm, 3.2 μm, 6.3 μm, 12.5 μm, 25 μm, etc. In this application, by providing a concave-convex structure 30a on the end face of the connecting post 321 and making the surface roughness of the end face greater than or equal to 1.6 μm, the friction between the contact surface of the bottom wall 312 and the connecting post 321 is increased, which helps to improve the hot-melt welding effect between the connecting post 321 and the cover 31.

[0069] It should be noted that, as Figure 5 As shown, the cover 31 can have multiple countersunk holes 310, which are arranged circumferentially around the cover 31. Correspondingly, the lower plastic 32 can have multiple connecting posts 321, each of which is inserted into a countersunk hole 310, thereby improving the overall connection strength between the cover 31 and the lower plastic 32. The location and number of the multiple countersunk holes 310 and multiple connecting posts 321 can be set according to actual needs and are not limited here.

[0070] Optionally, such as Figure 7 and Figure 8 As shown, the countersunk hole 310 also has a side wall 313, which is located between the opening 311 and the bottom wall 312. The side wall 313 has a protrusion 316 that protrudes into the countersunk hole 310. Along the thickness direction of the cover 31, a gap 317 is formed between the protrusion 316 and the bottom wall 312, and the connecting post 321 is at least partially embedded in the gap 317.

[0071] In this embodiment, a protrusion 316 is provided on the side wall 313 of the countersunk hole 310. A gap 317 exists between the protrusion 316 and the bottom wall 312. After the connecting post 321 melts, it can fill the gap 317 to form an undercut structure. Then, through the limiting cooperation between the undercut structure and the protrusion 316, the solidified connecting post 321 can be further prevented from coming out of the countersunk hole 310, thereby improving the bonding force between the connecting post 321 and the side wall 313 of the countersunk hole 310, and further enhancing the connection strength between the lower plastic 32 and the cover 31.

[0072] In some embodiments, such as Figure 7 As shown, the protrusions 316 on the sidewall 313 of the countersunk hole 310 can be continuously arranged around the circumference of the countersunk hole 310 to form an annular boss, and a gap 317 exists between the annular boss and the bottom wall 312. Alternatively, the protrusions 316 can also be arranged discontinuously around the circumference of the countersunk hole 310, that is, the protrusions 316 include multiple sub-protrusions, and the multiple protrusions are arranged at intervals around the circumference of the countersunk hole 310, and a gap 317 exists between each sub-protrusion and the bottom wall 312.

[0073] Understandably, during battery assembly, the high-frequency vibration waves generated by the ultrasonic hot-melt equipment 40 cause frictional heat between the connecting post 321 and the cover 31, causing the connecting post 321 to melt and fill the countersunk hole 310 in the cover 31. A protrusion 316 is provided on the sidewall 313 of the countersunk hole 310 so that the melted connecting post 321 can fill the gap 317 between the protrusion 316 and the bottom wall 312, forming an undercut structure. However, if the connecting post 321 does not melt sufficiently during the hot-melt process, the molten plastic liquid from the connecting post 321 may not flow sufficiently due to factors such as surface tension, and cannot effectively fill the gap 317, thus failing to form an effective undercut structure. In this embodiment, by providing a protrusion 316 on the sidewall 313 of the countersunk hole 310, and by providing a concave-convex structure 30a on the end face of the connecting post 321 facing the bottom wall 312 and / or on the bottom wall 312, the heat-melting efficiency of the connecting post 321 is improved, so that the connecting post 321 can melt quickly and fully, improving the wettability and fluidity of the connected post 321 after melting. The melted connecting post 321 is more likely to fill between the protrusion 316 and the bottom wall 312, thereby improving the connection strength between the lower plastic 32 and the cover 31.

[0074] In some embodiments, such as Figure 15 As shown, the bottom wall 312 of the countersunk hole 310 protrudes from the edge to the center toward the cover 31, so that the bottom wall 312 has a conical structure. This facilitates the flow of the molten plastic liquid after the connecting post 321 from the center to the edge of the bottom wall 312, which makes it easier for the plastic liquid to quickly fill the countersunk hole 310, thereby improving the connection strength between the solidified structure of the connecting post 321 and the cover 31.

[0075] Optionally, such as Figure 15 As shown, along the thickness direction of the cover 31, the height difference between the center and the edge of the bottom wall 312 is H; along the radial direction of the countersunk hole 310, the distance between the center and the edge of the bottom wall 312 is L, satisfying: 1≤L / H≤10. For example, L / H can be set to: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0076] In this embodiment, the bottom wall 312 is designed to protrude from the edge to the center toward the cover 31 to form a conical structure. By setting a reasonable range of L / H values, the taper of the conical surface formed by the bottom wall 312 can be controlled. This ensures that the bottom wall 312 is tilted to facilitate the flow of the molten plastic liquid after connecting the post 321 from the center of the bottom wall 312 to the edge, thereby fully filling the countersunk hole 310. At the same time, it avoids the taper of the bottom wall 312 being too large, which would increase the thickness of the cover 31 and occupy battery space. Also, an excessively large taper of the bottom wall 312 would make it difficult to process.

[0077] Optionally, such as Figure 15 As shown, along the thickness direction of the cover 31, the height difference H between the center and the edge of the bottom wall 312 satisfies: 0.05mm ≤ H ≤ 0.5mm. By setting the range of the height difference H between the center and the edge of the bottom wall 312, it is possible to ensure that the bottom wall 312 has a certain tilt angle to guide the molten plastic liquid after connecting the column 321, while avoiding the cover 31 being too thick, which would increase the overall weight of the top cover assembly 30 and the space it occupies.

[0078] Specifically, the height difference H between the center and the edge of the bottom wall 312 can be set to: 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, etc.

[0079] In other embodiments, such as Figure 15 As shown, along the radial direction of the countersunk hole 310, the distance L between the center and the edge of the bottom wall 312 satisfies: 0.5mm ≤ L ≤ 5mm. By setting the range of values ​​for the distance L between the center and the edge of the bottom wall 312, the size of the countersunk hole 310 provided in the cover 31 is limited. This avoids the countersunk hole 310 being too small to effectively connect with the connecting post 321, while also preventing the countersunk hole 310 from being too large, which would prevent the connecting post 321 from fully filling the countersunk hole 310 and thus reducing the connection strength between the connecting post 321 and the cover 31.

[0080] Specifically, the distance L between the center and the edge of the bottom wall 312 can be set to: 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, etc.

[0081] Optionally, such as Figure 16 and Figure 17 As shown, the bottom wall 312 is also provided with multiple flow channels 315, and the connecting post 321 is at least partially embedded in the flow channels 315. By providing multiple flow channels 315 on the bottom wall 312, the flow channels 315 can generate a capillary effect on the molten plastic liquid after the connecting post 321, allowing the plastic liquid to diffuse along the flow channels 315, thereby more fully filling the countersunk hole 310 and ensuring a full bond between the connecting post 321 and the cover 31 on the inner wall of the countersunk hole 310. At the same time, by providing flow channels 315 on the bottom wall 312, the contact area between the connecting post 321 and the cover 31 can also be increased, thereby further increasing the connection strength between the connecting post 321 and the cover 31.

[0082] In one embodiment, such as Figure 16As shown, multiple flow channels 315 are radially distributed around the center of the bottom wall 312. In this application, by setting multiple flow channels 315 radially distributed around the center of the bottom wall 312, the flow channels 315 are used to guide the molten plastic liquid after the connecting post 321 from the center of the bottom wall 312 to the edge, so that the plastic liquid can fully fill the countersunk hole 310, thereby improving the connection strength between the connecting post 321 and the cover 31.

[0083] In another embodiment, multiple guide grooves 315 can be arranged in an alternating manner to enable the molten plastic liquid after the connecting post 321 to fill different positions in the countersunk hole 310 more evenly, thereby improving the connection strength between the connecting post 321 and the cover 31.

[0084] In some embodiments, such as Figures 15 to 17 As shown, a boss 314 is provided at the center of the bottom wall 312. This is so that during the battery assembly process, the connecting post 321 is inserted into the countersunk hole 310 and contacts the boss 314. Then, the ultrasonic heat-melting device 40 is used to generate heat by friction between the connecting post 321 and the boss 314, so that the connecting post 321 melts and fills the countersunk hole 310 in the cover body 31.

[0085] Furthermore, a flow channel 315 is provided on the bottom wall 312 of the countersunk hole 310, and the flow channel 315 extends from the center of the bottom wall 312 to the edge, so as to guide the molten plastic liquid after the connecting column 321 from the center of the bottom wall 312 to the surrounding edges, so that the plastic liquid can quickly and fully fill the countersunk hole 310.

[0086] Furthermore, from the center to the edge of the bottom wall 312, the flow cross-sectional area of ​​the guide groove 315 increases, so that the molten plastic liquid after connecting column 321 can flow more easily from the center to the edge of the bottom wall 312, thereby improving the guiding effect of the guide groove 315. The flow cross-sectional area of ​​the guide groove 315 refers to the cross-sectional area along the direction perpendicular to the extension of the guide groove 315.

[0087] Optionally, embodiments of this application also provide a battery pack, including the battery cells described in the above embodiments.

[0088] In this embodiment, the battery cell 20 is disposed in the receiving cavity 101 of the housing 10, and the top cover assembly 30 covers the opening of the receiving cavity 101. The top cover assembly 30 includes a cover body 31 and a lower plastic 32. A connecting post 321 is provided on the lower plastic 32, and a countersunk hole 310 is provided in the cover body 31. The connecting post 321 extends at least partially into the countersunk hole 310. The connecting post 321 can be connected and fixed to the cover body 31 in the countersunk hole 310 by ultrasonic welding. Furthermore, by providing a concave-convex structure 30a on the end face of the connecting post 321, or by providing a concave-convex structure 30a on the bottom wall 312 of the countersunk hole 310, the friction between the connecting post 321 and the bottom wall 312 of the countersunk hole 310 can be increased during ultrasonic welding. At the same time, the ultrasonic energy can be more concentrated, allowing the hot melt post to melt quickly and fill the countersunk hole 310. This improves the connection strength between the lower plastic 32 and the top cover sheet, preventing the lower plastic 32 from separating from the top cover sheet. At the same time, the top cover assembly 30 structure of this application not only simplifies the processing technology but also makes the structure more compact, which helps to improve the space utilization of the battery.

[0089] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0090] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that, include: The housing (10), the battery cell (20), and the top cover assembly (30) are provided; the housing (10) has a receiving cavity (101), the battery cell (20) is disposed in the receiving cavity (101), and the receiving cavity (101) has an opening; The top cover assembly (30) includes a cover body (31) and a lower plastic (32). The cover body (31) is located at the cavity opening and connected to the housing (10). The lower plastic (32) is located on the side of the cover body (31) facing the receiving cavity (101). The side of the cover body (31) facing the lower plastic (32) has a countersunk hole (310). The side of the lower plastic (32) facing the cover body (31) has a connecting post (321). The connecting post (321) extends at least partially into the countersunk hole (310). The countersunk hole (310) has an opening (311) and a bottom wall (312) arranged opposite to each other. The end face of the connecting post (321) facing the bottom wall (312) or the bottom wall (312) has a concave-convex structure (30a).

2. The battery cell according to claim 1, characterized in that, The countersunk hole (310) also has a side wall (313), which is located between the opening (311) and the bottom wall (312). The side wall (313) has a protrusion (316) that protrudes into the countersunk hole (310). Along the thickness direction of the cover (31), a gap (317) is formed between the protrusion (316) and the bottom wall (312), and the connecting post (321) is at least partially embedded in the gap (317).

3. The battery cell according to claim 1, characterized in that, The surface roughness of the bottom wall (312) is greater than or equal to 1.6 μm; And / or, the surface roughness of the end face of the connecting post (321) facing the bottom wall (312) is greater than or equal to 1.6 μm.

4. The battery cell according to claim 1, characterized in that, The bottom wall (312) is a plane, and at least part of the bottom wall (312) protrudes into the countersunk hole (310) to form the concave-convex structure (30a); Alternatively, the bottom wall (312) may be at least partially recessed toward the direction away from the cover (31) to form the undulating structure (30a).

5. The battery cell according to claim 1, characterized in that, The bottom wall (312) protrudes from the edge to the center toward the cover (31).

6. The battery cell according to any one of claims 1-5, characterized in that, The bottom wall (312) is also provided with a plurality of guide grooves (315), and the connecting column is at least partially embedded in the guide grooves (315).

7. The battery cell according to claim 6, characterized in that, The multiple flow channels (315) are radially distributed around the center of the bottom wall (312), or the multiple flow channels (315) are staggered.

8. The battery cell according to claim 6, characterized in that, The flow channel extends from the center of the bottom wall (312) to the edge, and the flow cross-sectional area of ​​the flow channel (315) increases from the center to the edge.

9. The battery cell according to claim 6, characterized in that, The bottom wall (312) is also provided with a boss (314) at the center.

10. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1-9.

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