Cap assembly of lithium battery and lithium battery

Abstract

The utility model relates to the technical field of lithium battery manufacturing, in particular to a cap assembly of a lithium battery and the lithium battery. The cap assembly of the lithium battery comprises a top cover and a sealing ring, wherein the sealing ring comprises a top wall, the top wall is provided with a first end face and a second end face which are oppositely arranged, the first end face is provided with a first bonding layer, the second end face is provided with a second bonding layer, the first bonding layer is configured to be connected with the shell, and the second bonding layer is configured to be connected with the top cover; the elasticity of the first bonding layer is larger than that of the second bonding layer. The cap assembly of the lithium battery can improve the sealing performance of the buckling and sealing position of the lithium battery; the stress condition of the buckling and sealing position is improved, the service life of the sealing ring is prolonged, and cost is saved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery manufacturing technology, and in particular to a cap assembly for a lithium battery and a lithium battery. Background Technology

[0002] The cap assembly of a lithium battery is one of the important components of a lithium battery. It serves as a positive conductive terminal and a safety valve. At the same time, the cap of a lithium battery can also seal the cell to prevent electrolyte leakage.

[0003] In existing technologies, the cap assembly typically only applies adhesive between the sealing ring boss and the lower surface of the explosion-proof sheet. This can lead to a decrease in the sealing performance of the lithium battery during the encapsulation process, reducing the airtightness of the lithium battery. In addition, the current steel casing of lithium batteries is prone to local stress concentration at the sealing position, which affects the service life of the sealing ring and increases costs.

[0004] Therefore, there is an urgent need to design a cap assembly for a lithium battery and a lithium battery in order to solve the above technical problems. Utility Model Content

[0005] The primary objective of this invention is to provide a cap assembly for lithium batteries that improves the sealing performance of the lithium battery's sealing position; simultaneously, it improves the stress distribution at the sealing position, extends the service life of the sealing ring, and saves costs.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This utility model provides a cap assembly for a lithium battery, comprising:

[0008] Top cover;

[0009] A sealing ring, comprising a top wall having a first end face and a second end face disposed opposite to each other, a first adhesive layer being disposed on the first end face and a second adhesive layer being disposed on the second end face, the first adhesive layer being configured to connect with a housing and the second adhesive layer being connected with a top cover; the elasticity of the first adhesive layer being greater than the elasticity of the second adhesive layer.

[0010] As an optional technical solution for the cap assembly of a lithium battery, the elastic coefficient of the first adhesive layer is greater than that of the second adhesive layer.

[0011] As an optional technical solution for a cap assembly of a lithium battery, the ratio of the thickness of the first adhesive layer to the thickness of the top wall is 0.3 to 0.5; the ratio of the thickness of the second adhesive layer to the thickness of the top wall is 0.1 to 0.2.

[0012] As an optional technical solution for a lithium battery cap assembly, the width of the first adhesive layer is not greater than the width of the first end face, and the width of the second adhesive layer is not greater than the width of the second end face.

[0013] As an optional technical solution for the cap assembly of a lithium battery, the first adhesive layer includes silicone or rubber, and the second adhesive layer includes a two-component polyurethane adhesive.

[0014] As an optional technical solution for a cap assembly of a lithium battery, the cap assembly of the lithium battery further includes an explosion-proof sheet; the top cover is disposed on the explosion-proof sheet;

[0015] The sealing ring also includes a bottom wall opposite to the top wall and a side wall connecting the top wall and the bottom wall; the top cover and the explosion-proof sheet are located between the top wall and the bottom wall, and the edge of the top cover and / or the explosion-proof sheet abuts against the side wall;

[0016] The second adhesive layer is connected to the top cover or the explosion-proof sheet.

[0017] As an optional technical solution for a cap assembly of a lithium battery, the bottom wall protrudes towards the top wall to form a flange, and a receiving space is formed between the flange and the side wall, the receiving space being filled with an adhesive.

[0018] As an optional technical solution for the cap assembly of a lithium battery, the flange has an annular structure.

[0019] As an optional technical solution for a cap assembly of a lithium battery, the cap assembly of the lithium battery further includes a perforated plate, which is located below the explosion-proof sheet and is welded to the explosion-proof sheet.

[0020] As an optional technical solution for a cap assembly of a lithium battery, the cap assembly of the lithium battery further includes an insulating gasket, which is disposed between the perforated plate and the explosion-proof sheet.

[0021] The second objective of this invention is to provide a lithium battery that has good airtightness, improves the stress distribution of the sealing structure, avoids stress concentration, extends the service life of the sealing ring, and saves costs.

[0022] To achieve this objective, the present invention adopts the following technical solution:

[0023] This utility model provides a lithium battery, which includes a casing, a cell housed in the casing, and a cap assembly of the lithium battery as described in any of the above optional technical solutions. One end of the casing is provided with an opening, and the cap assembly of the lithium battery is sealed in the opening so that the sealing ring of the casing and the cap assembly of the lithium battery forms a snap-fit ​​structure.

[0024] As an optional technical solution for lithium batteries, the periphery of the casing is recessed with a roller groove, and the sealing ring of the lithium battery cap assembly is held between the roller groove and the fastening structure.

[0025] The beneficial effects of this utility model include at least the following:

[0026] This utility model provides a cap assembly for a lithium battery, which includes a top cover and a sealing ring. The sealing ring includes a top wall with a first end face and a second end face disposed opposite to each other. A first adhesive layer is disposed on the first end face, and a second adhesive layer is disposed on the second end face. The first adhesive layer is configured to connect to the housing, and the second adhesive layer is connected to the top cover. The elasticity of the first adhesive layer is greater than that of the second adhesive layer.

[0027] As described above, a first adhesive layer and a second adhesive layer are respectively provided on opposite sides of the top wall of the sealing ring. When the lithium battery casing and the lithium battery cap assembly are fastened together, the first adhesive layer can bond to the inner wall of the casing, and the second adhesive layer can bond to the top cap, thereby improving the sealing performance and airtightness of the lithium battery after fastening. Simultaneously, the elasticity of the first adhesive layer in this invention is greater than that of the second adhesive layer. This allows the first adhesive layer to undergo a larger deformation after the casing and the lithium battery cap assembly are fastened together. This larger deformation of the first adhesive layer improves the stress distribution at the casing fastening position, avoids stress concentration, improves the stability and sealing of the fastening position, extends the service life of the sealing ring, and saves costs.

[0028] This utility model also provides a lithium battery with good airtightness, which can improve the stress condition of the sealing structure (sealing position), avoid stress concentration, extend the service life of the sealing ring, and save costs. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the lithium battery provided in this embodiment of the utility model;

[0031] Figure 2 This is a cross-sectional view of the lithium battery provided in an embodiment of the present utility model;

[0032] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0033] Figure 4 This is a cross-sectional view of the cap assembly of the lithium battery provided in this embodiment of the present invention.

[0034] Figure Labels

[0035] 100. Explosion-proof sheet; 200. Top cover;

[0036] 300, sealing ring; 310, top wall; 320, bottom wall; 330, side wall; 340, flange; 350, receiving space;

[0037] 400, First adhesive layer; 500, Second adhesive layer; 600, Perforated plate; 700, Insulating gasket;

[0038] 10. Shell; 11. Roller groove. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown 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 utility model, and should not be construed as limiting this utility model.

[0046] This embodiment provides a cap assembly for a lithium battery, which can improve the sealing performance of the lithium battery's sealing position; at the same time, it improves the stress condition of the sealing position, extends the service life of the sealing ring, and saves costs.

[0047] like Figures 1-4As shown, the cap assembly of the lithium battery mainly includes a top cover 200 and a sealing ring 300. The sealing ring 300 includes a top wall 310, which has a first end face and a second end face disposed opposite to each other. A first adhesive layer 400 is disposed on the first end face, and a second adhesive layer 500 is disposed on the second end face. The first adhesive layer 400 is configured to connect with the housing 10, and the second adhesive layer 500 is connected with the top cover 200. The elasticity of the first adhesive layer 400 is greater than that of the second adhesive layer 500.

[0048] Based on the above design, by providing a first adhesive layer 400 and a second adhesive layer 500 on opposite sides of the top wall 310 of the sealing ring 300, when the lithium battery casing 10 is fastened to the lithium battery cap assembly, the first adhesive layer 400 can bond to the inner wall of the casing 10, and the second adhesive layer 500 can bond to the top cover 200, thereby improving the sealing performance and airtightness of the lithium battery after fastening. Simultaneously, in this embodiment, the elasticity of the first adhesive layer 400 is greater than that of the second adhesive layer 500. Thus, after the casing 10 is fastened to the lithium battery cap assembly, the first adhesive layer 400 can undergo a larger deformation. This larger deformation of the first adhesive layer 400 improves the stress distribution at the fastening position of the casing 10, avoids stress concentration, improves the stability and sealing of the fastening position, extends the service life of the sealing ring 300, and saves costs.

[0049] Optionally, in this embodiment, the ratio of the thickness of the first adhesive layer 400 to the thickness of the top wall 310 is 0.3 to 0.5; the ratio of the thickness of the second adhesive layer 500 to the thickness of the top wall 310 is 0.1 to 0.2. In other words, the thickness of the first adhesive layer 400 is greater than the thickness of the second adhesive layer 500. This allows the first adhesive layer 400 to further improve the stress condition at the sealing position of the housing 10, avoid stress concentration, extend the service life of the sealing ring 300, and save costs. At the same time, while ensuring that the second adhesive layer 500 can stably bond the sealing ring 300 to the top cover 200, the thickness of the second adhesive layer 500 is reduced as much as possible to save on sealing ring 300 materials and reduce costs.

[0050] Optionally, in this embodiment, the width of the first adhesive layer 400 is not greater than the width of the first end face, and the width of the second adhesive layer 500 is not greater than the width of the second end face. This avoids the phenomenon of adhesive overflow in the first adhesive layer 400 and the second adhesive layer 500, saves costs, and improves the product yield of the lithium battery cap assembly.

[0051] Optionally, in this embodiment, the first adhesive layer 400 comprises silicone or rubber, and the second adhesive layer 500 comprises a two-component polyurethane adhesive. In other words, the first adhesive layer 400 in this embodiment can be made of silicone or rubber, and the second adhesive layer 500 can be made of a two-component polyurethane adhesive. The elasticity of silicone and rubber is greater than that of the two-component polyurethane adhesive, thereby improving the stress condition at the fastening position of the housing 10 and avoiding stress concentration.

[0052] Furthermore, in this embodiment, the elastic modulus of the first adhesive layer 400 is greater than that of the second adhesive layer 500. For example, the elastic modulus of the first adhesive layer 400 is set to between 0.15 and 0.5, and the elastic modulus of the second adhesive layer 500 is set to between 0.01 and 0.1.

[0053] Of course, the first adhesive layer 400 and the second adhesive layer 500 in this embodiment can also be made of other materials, which will not be described in detail here.

[0054] like Figures 2-4 As shown, in this embodiment, the lithium battery cap assembly further includes an explosion-proof sheet 100; a top cover 200 is disposed on the explosion-proof sheet 100. The sealing ring 300 also includes a bottom wall 320 opposite to the top wall 310 and a side wall 330 connecting the top wall 310 and the bottom wall 320; the top cover 200 and the explosion-proof sheet 100 are located between the top wall 310 and the bottom wall 320, with the edges of the top cover 200 and / or the explosion-proof sheet 100 abutting against the side wall 330. A second adhesive layer 500 is connected to the top cover 200 or the explosion-proof sheet 100.

[0055] The explosion-proof plate 100 enhances the safety of the lithium battery. When thermal runaway is imminent inside the lithium battery, the explosion-proof plate 100 can open to relieve pressure. The top wall 310, bottom wall 320, and side wall 330 of the sealing ring 300 partially cover the explosion-proof plate 100 and the top cover 200, improving the overall integrity and stability of the lithium battery's cap assembly and extending its service life.

[0056] Optionally, in this embodiment, the top wall 310, bottom wall 320, and side wall 330 are integrally formed, which improves the processing efficiency and sealing performance of the sealing ring 300 and saves costs.

[0057] like Figure 4As shown, in this embodiment, the bottom wall 320 protrudes towards the top wall 310 to form a flange 340, and a receiving space 350 is formed between the flange 340 and the side wall 330. The receiving space 350 is filled with adhesive. This allows the adhesive to bond and fix the sealing ring 300 to the top cover 200 and / or the explosion-proof sheet 100, preventing the top cover 200 and / or the explosion-proof sheet 100 from loosening, ensuring the sealing performance of the lithium battery cap assembly, avoiding cell leakage, and improving the safety of lithium battery use.

[0058] Optionally, the adhesive in this embodiment can be a liquid glue with adhesive properties, and the sealing ring 300 can be made of polypropylene and EPDM material, which has elasticity and insulation.

[0059] Optionally, in this embodiment, the flange 340 is an annular structure, and the distance between the flange 340 and the sidewall 330 is the same everywhere. In other words, the flange 340, the bottom wall 320, and the sidewall 330 form an annular receiving space 350, which allows the receiving space 350 to hold more adhesive, thereby improving the stability and reliability of the bonding between the sealing ring 300 and the top cover 200 and / or the explosion-proof sheet 100.

[0060] Optionally, during assembly, adhesive can be pre-filled into the receiving space 350 of the sealing ring 300, and then the welded top cover 200 and explosion-proof sheet 100 can be placed between the top wall 310 and bottom wall 320 of the sealing ring 300. The sealing ring 300 can be hot-pressed to fix and seal the top cover 200 and explosion-proof sheet 100 with adhesive, thus ensuring the sealing performance of the lithium battery cap assembly.

[0061] Furthermore, the adhesive filling method can be mechanical filling. The sealing ring 300 is placed under the glue injection machine and rotated at a uniform speed. The glue injection machine injects a fixed amount of adhesive at a uniform speed, and the adhesive is evenly applied in the receiving space 350 of the sealing ring 300. Then, the sealing rings 300 coated with adhesive are neatly arranged in the drying device. After being dried with hot air for a certain period of time, the glue application is completed and it is ready for subsequent assembly.

[0062] like Figure 4 As shown, in this embodiment, the lithium battery cap assembly also includes a perforated plate 600, which is located below the explosion-proof sheet 100 and is welded to the explosion-proof sheet 100. Specifically, the perforated plate 600 can be ultrasonically welded, and then laser-welded to the electrode tab of the battery cell to achieve the positive electrode lead-out of the lithium battery.

[0063] Furthermore, the lithium battery cap assembly in this embodiment also includes an insulating gasket 700, which is disposed between the perforated plate 600 and the explosion-proof sheet 100. One side of the insulating gasket 700 is connected to the perforated plate 600, and the other side is connected to the explosion-proof sheet 100. The insulating gasket 700 prevents the perforated plate 600 and the explosion-proof sheet 100 from reconnecting after the cell CID is disconnected, thus preventing the cell from continuing to undergo chemical reactions and causing a short circuit hazard.

[0064] Alternatively, the insulating gasket 700 can be made of insulating materials such as plastic.

[0065] like Figures 1-3 As shown, this embodiment also provides a lithium battery, which includes a housing 10, a battery cell housed in the housing 10, and a cap assembly of the lithium battery. One end of the housing 10 is provided with an opening, and the cap assembly of the lithium battery is sealed in the opening so that the housing 10 and the sealing ring 300 of the cap assembly of the lithium battery form a snap-fit ​​structure.

[0066] Because this lithium battery has the cap assembly mentioned above, it has good airtightness, and at the same time, it can improve the stress condition of the sealing structure (sealing position), avoid stress concentration, extend the service life of the sealing ring 300, and save costs.

[0067] Alternatively, the housing 10 in this embodiment may be made of stainless steel.

[0068] like Figures 2-3 As shown, in this embodiment, a roller groove 11 is recessed on the periphery of the housing 10, and the sealing ring 300 of the lithium battery cap assembly is held between the roller groove 11 and the fastening structure. The roller groove 11 can support the sealing ring 300, thereby improving the stability and ease of installation of the lithium battery cap assembly and increasing assembly efficiency.

[0069] Optionally, the roller groove 11 in this embodiment is manufactured by roller pressing.

[0070] Obviously, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0071] Note that in the description of this specification, the references to terms such as "some embodiments," "other embodiments," 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 utility model. 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.

Claims

1. A cap assembly for a lithium battery, characterized in that, include: Top cover (200); A sealing ring (300) includes a top wall (310) having a first end face and a second end face disposed opposite to each other. A first adhesive layer (400) is disposed on the first end face, and a second adhesive layer (500) is disposed on the second end face. The first adhesive layer (400) is configured to be connected to the housing (10), and the second adhesive layer (500) is connected to the top cover (200). The elasticity of the first adhesive layer (400) is greater than that of the second adhesive layer (500).

2. The cap assembly for a lithium battery according to claim 1, characterized in that, The elastic modulus of the first adhesive layer (400) is greater than that of the second adhesive layer (500).

3. The cap assembly for a lithium battery according to claim 1, characterized in that, The ratio of the thickness of the first adhesive layer (400) to the thickness of the top wall (310) is 0.3 to 0.5; the ratio of the thickness of the second adhesive layer (500) to the thickness of the top wall (310) is 0.1 to 0.

2.

4. The cap assembly for a lithium battery according to claim 1, characterized in that, The width of the first adhesive layer (400) is not greater than the width of the first end face, and the width of the second adhesive layer (500) is not greater than the width of the second end face.

5. The cap assembly for a lithium battery according to claim 1, characterized in that, The first adhesive layer (400) comprises silicone or rubber, and the second adhesive layer (500) comprises a two-component polyurethane adhesive.

6. The cap assembly for a lithium battery according to claim 1, characterized in that, The cap assembly of the lithium battery also includes an explosion-proof sheet (100); the top cover (200) is disposed on the explosion-proof sheet (100); The sealing ring (300) also includes a bottom wall (320) opposite to the top wall (310) and a side wall (330) connecting the top wall (310) and the bottom wall (320); the top cover (200) and the explosion-proof plate (100) are located between the top wall (310) and the bottom wall (320), and the edges of the top cover (200) and / or the explosion-proof plate (100) abut against the side wall (330); The second adhesive layer (500) is connected to the top cover (200) or the explosion-proof sheet (100).

7. The cap assembly for a lithium battery according to claim 6, characterized in that, The bottom wall (320) protrudes towards the top wall (310) to form a flange (340), and a receiving space (350) is formed between the flange (340) and the side wall (330), and the receiving space (350) is filled with adhesive.

8. The cap assembly for a lithium battery according to claim 7, characterized in that, The flange (340) has a ring structure.

9. The cap assembly for a lithium battery according to claim 6, characterized in that, The cap assembly of the lithium battery also includes a perforated plate (600), which is located below the explosion-proof sheet (100) and is welded to the explosion-proof sheet (100).

10. The cap assembly for a lithium battery according to claim 9, characterized in that, The lithium battery cap assembly also includes an insulating gasket (700) disposed between the perforated plate (600) and the explosion-proof sheet (100).

11. A lithium battery, characterized in that, The lithium battery includes a housing (10), a cell housed within the housing (10), and a cap assembly for the lithium battery according to any one of claims 1-10. One end of the housing (10) is provided with an opening, and the cap assembly for the lithium battery is sealed to the opening so that the housing (10) and the sealing ring (300) of the cap assembly for the lithium battery form a snap-fit ​​structure.

12. The lithium battery according to claim 11, characterized in that, The housing (10) has a recessed roller groove (11) on its periphery, and the sealing ring (300) of the lithium battery cap assembly is held between the roller groove (11) and the fastening structure.

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