A cylindrical lithium battery and a cylindrical lithium battery

Abstract

The utility model relates to a lithium cell, concretely relates to a cylindrical lithium cell's casing structure and a cylindrical lithium cell, casing structure includes casing and top cap, casing is hollow and top end is open, the casing is in on the bottom end face and is provided with the winding core welding area suitable for with winding core contact and weld, winding core welding area is provided with at least one winding core welding convex stripe, winding core welding convex stripe is preferably multiple and becomes radial distribution, the bottom end face of casing still is provided with liquid injection hole and pressure -relief structure, top cap is provided with connecting groove, and the open end of casing is connected with connecting groove and is connected and cooperates, makes top cap and casing close -fit, and through the design of connecting groove, can insulate heat in the process of welding to top cap and casing periphery, protects winding core in casing, cylindrical lithium cell has applied above -mentioned casing structure, has omitted negative pole current collector, thereby has simplified structural member spare and production technology, has reduced the internal resistance of electric core, has improved the space inside casing structure.

Description

Technical Field

[0001] This utility model relates to lithium batteries, specifically to a cylindrical lithium battery casing structure and a cylindrical lithium battery. Background Technology

[0002] With the popularization of new energy vehicles, lithium-ion batteries, as their power components, play a crucial role in the development and upgrading of new energy vehicles due to their advantages such as high energy density, good power performance, excellent cycle life, low self-discharge rate, and environmental friendliness. Currently, the power batteries on the market are mainly prismatic; however, this type of battery has shortcomings in safety. Thermal runaway can easily lead to safety hazards for the battery pack. Furthermore, lithium-ion batteries can expand in volume during cycling due to factors such as gas production from side reactions, which also poses safety risks to the battery pack. Large cylindrical batteries, due to their shape, can better improve safety and stability and are gradually gaining attention in the industry.

[0003] For safety reasons, thermoelectric separation has become one of the important requirements for large cylindrical cells in the current market. That is, the welding end of the connecting piece and the directional pressure relief end of the cell are located at the top and bottom of the cell, respectively. In traditional welded large cylindrical batteries, the pressure relief end and the welding end of the connecting piece are located at the top of the cell, which cannot meet this design requirement. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a cylindrical lithium battery casing structure and a cylindrical lithium battery. The design adopts a bottom one-way pressure relief and a top sealing design, which solves the technical problems disclosed in the background art. Furthermore, by omitting the negative electrode current collector, the structural components and manufacturing process are simplified, the internal resistance of the cell is reduced, and the internal space of the casing structure is increased.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a cylindrical lithium battery casing structure, including a casing and a top cover. The casing is a hollow cylindrical structure with an open top. A core welding area is provided on the bottom surface of the casing, and at least one core welding protrusion is provided in the core welding area. An injection hole and a pressure relief structure are also provided on the bottom surface of the casing. The top cover is fitted onto the open end of the casing, and a connecting groove is provided on the top cover. The upper edge of the casing extends into the connecting groove and connects with the top cover. The connecting groove on the top cover improves the connection effect between the top cover and the casing and also protects the core. The core welding protrusion on the bottom surface of the casing improves the installation and welding effect of the core.

[0006] As an optional technical solution, the core welding protrusions are arranged radially along the bottom end face of the shell, and each core welding protrusion is distributed circumferentially.

[0007] As an optional technical solution, the core welding protrusions are eight in number.

[0008] As an optional technical solution, the pressure relief structure includes a pressure relief valve.

[0009] As an optional technical solution, an explosion-proof wire is provided on the bottom surface of the shell, and the explosion-proof wire forms a pressure relief zone on the bottom surface of the shell.

[0010] As an optional technical solution, the pressure relief valve is installed in the pressure relief zone.

[0011] As an optional technical solution, the pressure relief zone is located at the center of the bottom end face of the shell, and the core welding rod protrusions are distributed on the outside of the pressure relief zone.

[0012] As an optional technical solution, the connecting groove is an annular groove and is located at the edge of the top cover.

[0013] Based on the same concept, this utility model also provides a cylindrical lithium battery, including a core, a positive electrode current collector and the above-mentioned housing structure. The core is disposed inside the housing, and the negative end of the core is welded to the welding protrusions of each core. The positive electrode current collector is disposed on the top cover and welded to the electrode post of the top cover. The top cover is closed on the housing, and the upper edge of the housing is embedded in the connecting groove of the top cover and the housing and the outer ring of the top cover are welded together by the periphery.

[0014] Compared with the prior art, the advantages of this utility model are as follows: 1. By utilizing the shell structure of this application, the negative electrode current collector of the battery can be omitted, and the core can be in direct and sufficient contact with the shell, which reduces the internal resistance of the cell, simplifies the production process, and reduces the production cost; 2. The top cover is provided with an annular connecting groove, which facilitates the connection between the top cover and the shell, and also helps to isolate the core during the peripheral welding process; 3. The bottom of the shell is provided with a pressure relief structure, which facilitates the thermal separation after the cells are assembled, and has good prospects for mass production application. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the shell structure; Figure 2 This is a schematic diagram of the bottom of the casing; Figure 3 This is a schematic diagram of the interior of the casing; Figure 4 This is a schematic diagram of the top cover; Figure 5This is a cross-sectional view of the bottom of a cylindrical lithium battery. Figure 6 This is a cross-sectional view of the top of a cylindrical lithium battery. In the diagram: 1. Shell, 2. Top cover, 3. Core welding protrusion, 4. Pressure relief structure, 5. Connecting groove, 6. Core. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Example 1 like Figures 1-4 As shown, a cylindrical lithium battery casing structure includes a casing 1 and a top cover 2. The casing 1 is a hollow cylindrical structure with an open top. A core welding area is provided on the bottom surface of the casing 1, and at least one core welding protrusion 3 is provided in the core welding area. The casing 1 is used to accommodate a core 6. After the core 6 is inserted into the casing 1 from the top, the aluminum foil at the negative end of the core 6 contacts the core welding protrusions 3, facilitating welding between the core 6 and the casing 1. The design of the core welding protrusions 3 ensures that after the top cover 2 is installed on the casing 1, the pressure of the top cover 2 ensures full contact between the core 6 and the casing 1, thereby ensuring a firm weld between the core 6 and the casing 1.

[0019] The cylindrical lithium battery using the casing 1 structure of this embodiment has the core 6 negative electrode directly welded to the bottom of the casing 1. Compared with existing lithium batteries, the negative electrode current collector is omitted, the usable space inside the casing 1 is effectively increased, and the battery structure, components and battery manufacturing process are simplified, and the internal resistance of the cell is reduced.

[0020] In a preferred embodiment, the core welding protrusion 3 is an elongated protrusion, arranged radially along the bottom end face of the housing 1, with each core welding protrusion 3 distributed circumferentially and arranged radially to facilitate complete welding of the core 6 to the bottom end face of the housing 1. Preferably, there are eight core welding protrusions 3.

[0021] A pressure relief structure 4 is also provided on the bottom end face of the housing 1 to ensure the safety of the core 6. The pressure relief structure 4 is a pressure relief valve. An explosion-proof line is also provided on the bottom end face of the housing 1. By etching the explosion-proof line on the bottom end face of the housing 1, a pressure relief zone is formed on the bottom end face of the housing 1. The pressure relief valve is located in the pressure relief zone, forming a double pressure relief. Alternatively, if only a pressure relief valve or only an explosion-proof line is provided on the bottom end face of the housing 1 to form a pressure relief zone, a unidirectional pressure relief effect can also be achieved, ensuring the safety of the core. The pressure relief valve and / or pressure relief zone is located at the center of the bottom end face of the housing 1, and the core welding protrusions 3 are distributed circumferentially outside the pressure relief zone / pressure relief valve.

[0022] A liquid injection hole is provided on the bottom end face of the casing 1 for injecting liquid into the casing 1 during the battery production process.

[0023] The top cover 2 is provided with a connecting groove 5, which is an annular groove adapted to the size of the top port of the housing 1. When the top cover 2 is closed on the housing 1, the top end of the housing 1 extends into the connecting groove 5. The housing 1 and the top cover 2 are welded by peripheral welding. The connecting groove 5 is located at the edge of the top cover 2. The top cover 2 is provided with a connecting groove 5 suitable for connecting with the housing 1. The top cover 2 can easily fit with the housing 1, which can ensure the stability of the fit between the top cover 2 and the housing 1. Moreover, during the peripheral welding process, it can also play a role in blocking high temperature and protecting the core.

[0024] Example 2 like Figures 1-6 As shown, a cylindrical lithium battery includes a core 6, a positive current collector, and the housing 1 structure described in Example 1. The positive current collector is disposed on a top cover 2 and welded to the terminal post of the top cover 2. The core 6 is installed into the housing 1 from the top, with the positive end of the core 6 facing upwards and the negative end facing downwards. The negative end of the core 6 is in contact with the welding protrusions 3 of each core. After the core 6 is placed into the housing 1, the top cover 2 is installed on top of the housing 1. The top cover 2 is welded to the housing 1 by peripheral welding. The closing force of the top cover 2 ensures that the negative end of the core 6 is fully in contact with the welding protrusions 3. By using external laser penetration welding, the welding protrusions 3 of each core are welded to the negative end of the core 6, achieving direct welding of the core 6 to the housing 1. This eliminates the need for a negative current collector, thereby reducing the internal resistance of the cell, simplifying the production process, and reducing production costs. The height and other specifications of the welding protrusions 3 of each core should be consistent. The mutual squeezing action can cause a slight indentation in the tabs of the core 6, which can also fix the core 6 and prevent it from shaking.

[0025] The injection hole at the bottom of the housing 1 is used to inject electrolyte. The top cover 2 is provided with a connecting groove 5, which helps to improve the fit between the top cover 2 and the housing 1, ensuring that the top cover 2 and the housing 1 can fit stably. Moreover, this design allows the top cover 2 and the housing 1 to block high temperature and protect the core during the peripheral welding process.

[0026] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. 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.

[0027] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A cylindrical lithium battery casing (1) structure, characterized in that: The shell (1) includes a housing (1) and a top cover (2). The housing (1) is a cylindrical structure with a hollow interior and an open top. The bottom surface of the housing (1) has a core (6) welding area. The core (6) welding area has at least one core welding protrusion (3). The bottom surface of the housing (1) also has an injection hole and a pressure relief structure (4). The top cover (2) covers the open end of the housing (1). The top cover (2) has a connecting groove (5). The upper edge of the housing (1) extends into the connecting groove (5) and connects with the top cover (2).

2. The casing (1) structure of a cylindrical lithium battery according to claim 1, characterized in that: The core welding protrusions (3) are arranged radially along the bottom end face of the shell (1), and each core welding protrusion (3) is distributed circumferentially.

3. The casing (1) structure of a cylindrical lithium battery according to claim 2, characterized in that: There are 8 core welding protrusions (3).

4. The casing (1) structure of a cylindrical lithium battery according to claim 2, characterized in that: The pressure relief structure (4) includes a pressure relief valve.

5. The casing (1) structure of a cylindrical lithium battery according to claim 4, characterized in that: An explosion-proof wire is provided on the bottom surface of the shell (1), and the explosion-proof wire forms a pressure relief zone on the bottom surface of the shell (1).

6. The casing (1) structure of a cylindrical lithium battery according to claim 5, characterized in that: The pressure relief valve is located in the pressure relief zone.

7. The casing (1) structure of a cylindrical lithium battery according to claim 5, characterized in that: The pressure relief zone is located at the center of the bottom end face of the shell (1), and the welding rod of the core (6) is distributed outside the pressure relief zone.

8. The casing (1) structure of a cylindrical lithium battery according to claim 1, characterized in that: The connecting groove (5) is an annular groove and is located at the edge of the top cover (2).

9. A cylindrical lithium battery, characterized in that: The structure includes a core (6), a positive current collector and a housing (1) as described in any one of claims 1-8. The core (6) is disposed inside the housing (1). The negative end of the core (6) is welded to the welding protrusions (3) of each core. The positive current collector is disposed on the top cover (2) and welded to the pole of the top cover (2). The top cover (2) covers the housing (1). The upper edge of the housing (1) is embedded in the connecting groove (5) of the top cover (2) and the outer ring of the housing (1) is welded to the top cover (2) by peripheral welding.

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