Cover cap assembly, battery cell and battery

Abstract

A cover cap assembly (001), a battery cell, and a battery, relating to the technical field of batteries. The cover cap assembly (001) comprises a cover cap (012); the cover cap (012) comprises a top cover (121) and an explosion-proof piece (122); the top cover (121) has a first side surface and a second side surface which are arranged opposite to each other, the explosion-proof piece (122) being partially attached to the first side surface; the periphery of the explosion-proof piece (122) is provided with an edge part (1222); the edge part (1222) is arranged at the periphery of the top cover (121), the plane where the top surface of the edge part (1222) is located not exceeding the plane where the second side surface is located.

Description

Cap assembly, battery cell and battery

[0001] This application claims priority to Chinese patent application No. 202323435859.9 filed with the Patent Office of China on December 14, 2023. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a cap assembly, a battery cell and a battery. Background Art

[0003] In the related art, the main structure of a battery cell includes a steel shell, a cap and an electrode assembly. The cap and the steel shell cover each other to define an installation cavity, and the electrode assembly is arranged in the installation cavity. The negative electrode tab of the electrode assembly is electrically connected to the shell, so that the shell is negatively charged. The positive electrode of the electrode assembly is electrically connected to the cap, so that the cap is positively charged. A sealing ring is provided between the steel shell and the cap. In order to improve the sealing performance, the parts of the steel shell on both sides of the sealing ring need to be rolled to form buckle edges and rolling grooves on the steel shell. The buckle edge is formed at the end of the steel shell and wraps the periphery of the sealing ring. The rolling groove is formed on the side of the steel shell on the side of the sealing ring away from the buckle edge and squeezes the sealing ring. SUMMARY OF THE INVENTION

[0004] Since the flat section of the negatively charged buckle edge is relatively short, the electrical connection between the flat section of the buckle edge and related components is poor in operability and stability.

[0005] The present application provides a cap assembly, a battery cell, and a battery, which can improve the operability and electrical connection stability of the flat section of the buckle edge and related components.

[0006] In the first aspect, the present application provides a cap assembly, which includes a cap; the cap includes a top cover and an explosion-proof plate, the top cover has a first side surface and a second side surface arranged opposite to each other, the explosion-proof plate is partially attached to the first side surface, and the periphery of the explosion-proof plate is provided with an edge portion, the edge portion is provided at the periphery of the top cover, and the plane where the top surface of the edge portion is located does not exceed the plane where the second side surface is located.

[0007] In a second aspect, the present application provides a battery cell comprising a steel shell, an electrode assembly, and the aforementioned cap assembly. The steel shell has an opening; the electrode assembly is disposed within the steel shell; and the cap assembly seals the opening. The steel shell has a buckle edge disposed at the end near the opening. The buckle edge has a flattened section located on the side of the top cover facing away from the blast-proof disk and perpendicular to the axis of the blast-proof disk.

[0008] In a third aspect, the present application further provides a battery comprising a plurality of the aforementioned battery cells, wherein the plurality of battery cells are connected in series or in parallel. Beneficial effects

[0009] In the present application, by limiting the plane of the edge of the explosion-proof disk to not exceed the plane of the second side surface, the cap is configured as a non-edged structure, thereby reducing the height of the cap's perimeter and the overall height of the cap assembly's perimeter. This reduces the height of the steel shell that mates with the cap assembly, allowing this reduced height to be added to the length of the flat section of the buckle edge. This increases the electrical connection area between the flat section of the buckle edge and related components, ultimately improving the operability and stability of the electrical connection between the flat section of the buckle edge and related components. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a schematic structural diagram of a cap assembly in the related art;

[0011] FIG2 is a schematic structural diagram of a steel shell after groove rolling provided by an embodiment of the present application;

[0012] FIG3 is a schematic structural diagram of a steel shell after edge buckling provided by an embodiment of the present application;

[0013] FIG4 is a schematic structural diagram of a cap assembly provided in an embodiment of the present application;

[0014] FIG5 is an enlarged view of point A in FIG4 ;

[0015] FIG6 is a schematic structural diagram of another cap assembly provided in an embodiment of the present application;

[0016] FIG7 is a schematic diagram of the cooperation between the periphery of a top cover and the periphery of a burst-proof disk provided in an embodiment of the present application;

[0017] FIG8 is a schematic structural diagram of an explosion-proof disk provided in an embodiment of the present application;

[0018] FIG9 is a schematic diagram showing the cooperation between the periphery of another top cover and the periphery of a burst-proof disk provided in an embodiment of the present application;

[0019] FIG10 is a schematic structural diagram of another cap assembly provided in an embodiment of the present application;

[0020] FIG11 is an enlarged view of point B in FIG10 ;

[0021] FIG12 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0022] FIG13 is a schematic diagram of the cooperation between the cap assembly and the steel shell provided in an embodiment of the present application;

[0023] FIG14 is a comparison diagram of the increase in the length of the buckle edge provided in an embodiment of the present application;

[0024] FIG15 is an enlarged view of point C in FIG13 .

[0025] Description of Figure Numbers:

[0026] 001-cap assembly;

[0027] 011-sealing ring; 111-sealing groove; 112-inclined surface; 113-main body; 114-supporting part; 1141-first conical section; 1142-second conical section;

[0028] 012-cap; 121-top cover; 1211-outer circumference of the top cover; 122-explosion-proof disk; 1221-body; 1222-edge; 12221-inner circumference of the retaining ring; 1223-edge;

[0029] 014-well plate;

[0030] 015-gasket;

[0031] 002-Steel shell; 021-Buckling edge; 211-Flat section; 022-Grooving; 023-Opening;

[0032] 003-Electrode assembly. Modes for Carrying Out the Invention

[0033] Before introducing the cap assembly, battery cell and battery of the present application, relevant background information of the embodiments of the present application is first introduced.

[0034] In the related art, the cap assembly includes a sealing ring and a cap. The cap includes a top cover and an explosion-proof plate that is partially fitted with the top cover. The sealing ring wraps the periphery of the top cover and the explosion-proof plate. The cap has a edging structure. Specifically, the periphery of the explosion-proof plate is provided with an edging that wraps the periphery of the top cover, as shown in FIG1 , which is a structural schematic diagram of the cap assembly in the related art. In order to improve the sealing between the cap assembly and the steel shell, after the cap assembly is installed in the steel shell, the steel shell needs to be grooved and sealed in sequence. After grooving, a groove is formed on the surface of the steel shell, as shown in FIG2 , which is a structural schematic diagram of the steel shell after grooving provided in an embodiment of the present application; the upper edge of the groove is at a distance L1 from the end of the steel shell. Sealing is to seal the end of the steel shell so that the end of the steel shell forms a buckle edge that wraps the sealing ring, as shown in FIG3 , which is a structural schematic diagram of the steel shell after buckling provided in an embodiment of the present application. In FIG3 , after sealing, the dimension L1 correspondingly changes to the height dimension L2 , the rounded corner dimension L3 and the length of the flat section of the buckle edge L4 .

[0035] When the buckle edge serves as the negative terminal of a battery cell, its flat section length L4 is too small, which is not conducive to electrical connection between battery cells. Simply increasing the size of L1 would lead to increased material costs, changes in mold fixture dimensions, and process changes. Therefore, the purpose of this application is to increase the flat section length L4 of the buckle edge without increasing the size of L1.

[0036] Based on this, the present application provides a cap assembly, a battery cell and a battery, which are described in detail below.

[0037] Please refer to Figure 4, which is a structural diagram of the cap assembly 001 provided by an embodiment of the present application. The embodiment of the present application provides a cap assembly 001, which includes a cap 012, and the cap 012 includes a top cover 121 and an explosion-proof plate 122. The top cover 121 has a first side surface and a second side surface that are arranged opposite to each other. The explosion-proof plate 122 is partially attached to the first side surface. The periphery of the explosion-proof plate 122 is provided with an edge portion 1222, and the edge portion 1222 is provided at the periphery of the top cover, and the plane where the top surface of the edge portion 1222 is located does not exceed the plane where the second side surface is located, as shown in Figure 5, which is an enlarged view of point A in Figure 4.

[0038] As will be understood, cap assembly 001 also includes a sealing ring 011. A sealing groove 111 is provided on the inner circumference of sealing ring 011, into which the periphery of top cover 121 and the periphery of explosion-proof disk 122 are inserted, as shown in FIG6 , which is a schematic structural diagram of another cap assembly 001 provided in an embodiment of the present application. Sealing ring 011 is insulating. When cap assembly 001 is applied to a battery cell, sealing ring 011 insulates top cover 121 and explosion-proof disk 122 from the steel shell 002 of the battery cell.

[0039] The explosion-proof disc 122 is a metal sheet with a weak structure. When the pressure inside the battery cell reaches a threshold, the pressure breaks through the weak structure, relieving the pressure inside the battery cell. The top cover 121 serves as the positive electrode of the battery cell. The explosion-proof disc 122 is electrically connected to the top cover 121 to transmit the current and voltage of the positive electrode of the battery cell to the top cover 121.

[0040] In addition, the groove walls on both sides of the sealing groove 111 are respectively fitted with the top cover 121 and the explosion-proof disk 122 to form sealing surfaces on the top cover 121 and the explosion-proof disk 122 .

[0041] Exemplarily, sealing ring 011 is an insulating rubber ring resistant to electrolyte corrosion. Only the periphery of explosion-proof disk 122 is in contact with the periphery of top cover 121. Explosion-proof disk 122 is a metal sheet with multiple notches. The center portion of top cover 121 protrudes away from explosion-proof disk 122, creating a buffer space between top cover 121 and explosion-proof disk 122 to protect against high-pressure fluid impact.

[0042] In this embodiment, by limiting the plane of the edge portion 1222 of the explosion-proof disk 122 to not exceed the plane of the second side surface, the cap 012 is configured as a non-edged structure. This reduces the peripheral height of the cap 012 and the overall peripheral height of the cap assembly 001. This reduces the height dimension of the steel shell that mates with the cap assembly 001, allowing this reduced dimension to be added to the length of the flattened section 211 of the buckle edge 021. This increases the electrical connection area between the flattened section 211 of the buckle edge 021 and related components, improving the operability and stability of the electrical connection between the flattened section 211 of the buckle edge 021 and related components.

[0043] The height dimension of the steel shell that matches the cap assembly 001 is dimension L2 in Figure 3. In addition, the length L4 of the flattened section 211 is ≥ 1 mm.

[0044] Please refer to Figure 7, which is a schematic diagram of the cooperation between the periphery of a top cover 121 and the periphery of an explosion-proof plate 122 provided in an embodiment of the present application. In one embodiment, the explosion-proof plate 122 includes a main body 1221 and a retaining ring provided on the main body 1221. The main body 1221 is partially attached to the first side. The edge portion is the retaining ring. One side of the retaining ring is connected to the main body 1221, and the other side of the retaining ring does not exceed the second side, and the inner circumference 12221 of the retaining ring is in contact with the outer circumference 1211 of the top cover. Among them, the structure of the inner circumference 12221 of the retaining ring is shown in Figure 8, which is a schematic diagram of the structure of the explosion-proof plate 1222 provided in an embodiment of the present application.

[0045] It can be understood that the surface of the retaining ring includes an inner circumferential surface, an outer circumferential surface, a first end surface connected to one end of the outer circumferential surface and the inner circumferential surface, and a second end surface connected to the other end of the outer circumferential surface and the inner circumferential surface. The inner circumferential surface and the outer circumferential surface are parallel to the axis of the cap assembly 001, while the first end surface and the second end surface are perpendicular to the axis of the cap assembly 001. One side and the other side of the retaining ring are the first end surface and the second end surface, respectively, and the first end surface is connected to the body 1221.

[0046] In addition, the maximum height of the retaining ring is flush with the side of the periphery of the top cover 121 away from the explosion-proof plate 122, as shown in Figure 9, which is a schematic diagram of the cooperation between the periphery of another top cover 121 and the periphery of the explosion-proof plate 122 provided in an embodiment of the present application.

[0047] Exemplarily, the main body 1221 and the retaining ring are integrally formed, and the retaining ring can be formed by stamping a metal sheet, or by rolling a metal sheet to form a retaining ring structure. The inner circumference 12221 of the retaining ring abuts the outer circumference 1211 of the top cover, so that the inner circumference 12221 of the retaining ring and the outer circumference 1211 of the top cover have an interference fit. Optionally, the interference fit has an interference amount of 0 to 0.5 mm, including but not limited to 0, 0.1 mm, 0.2 mm, 0.3 mm, and 0.5 mm. Thus, by limiting the interference amount, it is possible to avoid excessive gaps, thereby avoiding insufficient sealing; and having a suitable interference amount facilitates the assembly of the top cover 121 and the explosion-proof disk 122.

[0048] In this embodiment, by abutting the inner circumferential surface 12221 of the retaining ring with the outer circumferential surface 1211 of the top cover, the friction force generated by the abutment can improve the stability of the fit between the top cover 121 and the explosion-proof plate 122, thereby improving the connection reliability between the top cover 121 and the explosion-proof plate 122.

[0049] 6 , in one embodiment, the end surface of the sealing ring 011 located at the end of the top cover 121 away from the explosion-proof disk 122 is a slope 112 , and the distance between the slope 112 and the top cover 121 gradually increases along the direction close to the axis of the sealing ring 011 .

[0050] It will be appreciated that, to facilitate electrical connection with related components, the flat section 211 of the buckle edge 021 is perpendicular to the axis of the burst-proof disk 122. Based on this, in this embodiment, by configuring the end face of the sealing ring 011 facing away from the burst-proof disk 122 as the inclined surface 112, the end face of the sealing ring 011 facing away from the burst-proof disk 122 can be tightly abutted against the flat section 211 of the buckle edge 021, thereby increasing the pressure between the flat section 211 of the buckle edge 021 and the end face of the sealing ring 011 facing away from the burst-proof disk 122, thereby improving the sealing performance between the flat section 211 of the buckle edge 021 and the end face of the sealing ring 011 facing away from the burst-proof disk 122.

[0051] Please refer to Figure 10, which is a schematic diagram of the structure of another cap assembly 001 provided in an embodiment of the present application. In one embodiment, cap assembly 001 further includes an orifice plate 014 and a gasket 015. Orifice plate 014 is located on the side of explosion-proof disc 122 facing away from top cover 121. The center of orifice plate 014 is connected to the center of explosion-proof disc 122. Gasket 015 is located at the periphery of orifice plate 014 and is disposed between orifice plate 014 and explosion-proof disc 122.

[0052] It can be understood that the orifice plate 014 can be electrically connected to the positive busbar of the electrode assembly 003.

[0053] Exemplarily, the gasket 015 is an annular structure, which is coaxially arranged with the sealing ring 011.

[0054] In this embodiment, the orifice plate 014 is insulated and supported from one side of the explosion-proof plate 122 by a gasket 015, so that except for the central portion, the explosion-proof plate 122 and the orifice plate 014 are connected to each other, and there is a gap between the remaining portions. Therefore, when the central portion of the orifice plate 014 is ruptured by the high-pressure gas in the battery cell, the electrical connection between the orifice plate 014 and the explosion-proof plate 122 can be disconnected, and then the battery cell can be disconnected from the circuit, thereby improving the safety of the battery cell.

[0055] Please refer to Figure 11, which is an enlarged view of point B in Figure 10. In one embodiment, the sealing ring 011 includes a main body 113 and a supporting portion 114 connected in sequence. The sealing groove 111 is provided on the main body 113. The supporting portion 114 is located on the side of the orifice plate 014 facing away from the top cover 121 and is disposed opposite the periphery of the orifice plate 014 along the axial direction of the sealing ring 011.

[0056] Exemplarily, the main body portion 113 and the supporting portion 114 are integrally formed, specifically, can be integrally injection molded.

[0057] Since only the center of the orifice plate 014 is connected to the center of the explosion-proof disc 122, the connection stability between the two is poor. In particular, when the battery cell vibrates or shakes, the orifice plate 014 is easily separated from the explosion-proof disc 122. Based on this, in this embodiment, by providing a supporting portion 114, when the rolling groove 022 is machined on the outer peripheral surface of the steel shell 002, the inner wall of the steel shell 002 located between the rolling groove 022 and the sealing ring 011 abuts against the supporting portion 114, and pushes the supporting portion 114 to move toward the orifice plate 014 and contact the orifice plate 014, so that the orifice plate 014 can be supported and limited by the supporting portion 114 to prevent it from separating from the explosion-proof disc 122, thereby improving the structural stability of the cap assembly 001.

[0058] 11 , in one embodiment, the support portion 114 is a conical ring structure having a large diameter end and a small diameter end. The large diameter end is connected to the main body 113 . The small diameter end is disposed opposite to the periphery of the orifice plate 014 along the axial direction of the sealing ring 011 .

[0059] In this embodiment, by configuring the supporting portion 114 as a conical ring structure, the material usage can be reduced and the resistance of the inner wall of the steel shell 002 when pushing the supporting portion 114 toward the orifice plate 014 can be reduced.

[0060] Exemplarily, the supporting portion 114 includes a first conical segment 1141 and a second conical segment 1142, and the second conical segment 1142 is connected to the main body 113 through the first conical segment 1141. When the groove is processed on the outer wall of the steel shell, the inner wall of the steel shell pushes the supporting portion 114 to move toward the orifice plate 014 until the second conical segment 1142 contacts the orifice plate 014, and the inner circumferential surface of the second conical segment 1142 fits against the side of the orifice plate 014 facing away from the explosion-proof plate 122.

[0061] Please refer to Figure 12, which is a schematic diagram of the structure of a battery cell provided by an embodiment of the present application. An embodiment of the present application provides a battery cell, which includes a steel shell 002, an electrode assembly 003 and a cap assembly 001 disclosed in some embodiments of the present application. The steel shell 002 has an opening 023; the electrode assembly 003 is arranged in the steel shell 002; and the cap assembly 001 blocks the opening 023. Among them, a buckle edge 021 is provided at the end of the steel shell 002 near the opening 023, and the buckle edge 021 has a flat section 211. The flat section 211 is located on the side of the top cover 121 away from the explosion-proof plate 122, and the flat section 211 is perpendicular to the axis of the explosion-proof plate 122, as shown in Figure 13. Figure 13 is a schematic diagram of the cooperation between the cap assembly 001 and the steel shell 002 provided by an embodiment of the present application.

[0062] It can be understood that the negative electrode of electrode assembly 003 is electrically connected to steel shell 002, thereby making steel shell 002 negatively charged. The positive electrode of electrode assembly 003 is electrically connected to explosion-proof disk 122, specifically through the tab, current collecting plate, and orifice plate 014, thereby making top cover 121 positively charged.

[0063] In this embodiment, by adopting the cap assembly disclosed in some embodiments of the present application, the height dimension of the portion of the cap assembly that cooperates with the edging 1223 is reduced, thereby reducing the height dimension of the steel shell that cooperates with the cap assembly 001, so that the reduced dimension of this part can be increased to the length of the flat section 211 of the buckle edge 021, thereby increasing the electrical connection area between the flat section 211 of the buckle edge 021 and related components, as shown in Figure 14, which is a comparison diagram of the increase in the length of the buckle edge 021 provided in the embodiment of the present application.

[0064] Please refer to Figure 15, which is an enlarged view of point C in Figure 13. In one embodiment, a rolling groove 022 is provided on the outer circumference of the steel shell 002, and the inner wall of the steel shell 002 located between the rolling groove 022 and the sealing ring 011 abuts against the sealing ring 011.

[0065] In this embodiment, the inner wall of the steel shell 002 located between the rolling groove 022 and the sealing ring 011 abuts against the sealing ring 011, which can squeeze the sealing ring 011, thereby increasing the pressure on the sealing surface of the sealing ring 011, and then improving the sealing between the steel shell 002 and the cap assembly 001.

[0066] An embodiment of the present application further provides a battery, which includes a plurality of battery cells disclosed in some embodiments of the present application, and the plurality of battery cells are connected in series or in parallel.

[0067] It can be understood that when multiple battery cells are connected in series, the flat section 211 of the buckle edge 021 of one battery cell among two adjacent battery cells is electrically connected to the top cover 121 of the other battery cell, specifically, they are electrically connected through the series connection bar.

[0068] The battery disclosed in this embodiment can be used in, but is not limited to, electrical devices such as electric toys, electric tools, ships, aircraft or vehicles. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles and spacecraft, etc. The vehicle can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid car or an extended-range car, etc. The battery can be set at the bottom, head or tail of the vehicle. The battery can be used as a control power source for the vehicle, and can also be used as a driving power source for the vehicle.

Claims

1. A cap assembly (001), comprising a cap (012), the cap (012) comprising a top cover (121) and an explosion-proof plate (122), the top cover (121) having a first side surface and a second side surface disposed opposite to each other, the explosion-proof plate (122) being partially attached to the first side surface, and an edge portion (1222) being disposed at a periphery of the explosion-proof plate (122), the edge portion (1222) being disposed at a periphery of the top cover (121), and a plane where a top surface of the edge portion (1222) is located does not exceed a plane where the second side surface is located.

2. The cap assembly (001) according to claim 1, wherein: The explosion-proof plate (122) includes a main body (1221) and a retaining ring arranged on the main body (1221), the main body (1221) is partially attached to the first side surface, the edge portion (1222) is the retaining ring, one side of the retaining ring is connected to the main body (1221), and the other side of the retaining ring does not exceed the second side surface.

3. The cap assembly (001) according to claim 2, wherein: The inner circumferential surface (12221) of the retaining ring abuts against the outer circumferential surface of the top cover (121).

4. The cap assembly (001) according to claim 2 or 3, wherein: The body (1221) and the retaining ring are integrally formed.

5. According to the cap assembly (001) according to any one of claims 1 to 4, the cap assembly (001) further comprises a orifice plate (014) and a gasket (015), the orifice plate (014) is located on the side of the explosion-proof plate (122) away from the top cover (121), the central part of the orifice plate (014) is connected to the central part of the explosion-proof plate (122), the gasket (015) is located at the periphery of the orifice plate (014), and the gasket (015) is arranged between the orifice plate (014) and the explosion-proof plate (122).

6. The cap assembly (001) according to claim 5, further comprising a sealing ring (011), wherein a sealing groove (111) is provided on an inner peripheral surface of the sealing ring (011), and the periphery of the top cover (121) and the periphery of the explosion-proof plate (122) are both inserted into the sealing groove (111).

7. The cap assembly (001) according to claim 6, wherein: The sealing ring (011) comprises a main body (113) and a supporting portion (114) which are connected in sequence, the sealing groove (111) is arranged on the main body (113), the supporting portion (114) is located on a side of the orifice plate (014) away from the top cover (121), and is arranged opposite to the periphery of the orifice plate (014) along the axial direction of the sealing ring (011).

8. The cap assembly (001) according to claim 7, wherein: The supporting portion (114) is a conical ring structure, and has a large diameter end and a small diameter end, wherein the large diameter end is connected to the main body (113); along the axial direction of the sealing ring (011), the small diameter end is arranged opposite to the periphery of the orifice plate (014).

9. A battery cell, comprising: A steel shell (002) having an opening (023); An electrode assembly (003) is disposed in the steel shell (002); The cap assembly (001) according to any one of claims 1 to 8, blocking the opening (023); The steel shell (002) is provided with a buckle edge (021) at the end close to the opening (023), and the buckle edge (021) has a flat section (211). The flat section (211) is located on a side of the top cover (121) away from the explosion-proof plate (122), and the flat section (211) is perpendicular to the axis of the explosion-proof plate (122).

10. The battery cell according to claim 9, wherein: The outer peripheral surface of the steel shell (002) is provided with a rolling groove (022).

11. A battery, comprising a plurality of battery cells as claimed in claim 9 or 10, wherein the plurality of battery cells are connected in series or in parallel.

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