Power battery housing

Abstract

Disclosed in the present invention is a power battery housing, comprising a housing side wall and a housing bottom wall. The housing side wall and the housing bottom wall are fixedly connected or integrally formed to form a power battery housing for accommodating a battery cell; the housing bottom wall comprises a structural portion, and a first soldering portion and a plurality of second soldering portions distributed on the structural portion; the bottom surface of the first soldering portion is lower than the plane where the bottom surface of the structural portion is located, and the first soldering portion is soldered to a busbar; and the second soldering portion is soldered to one of tabs of the battery cell or one of end surfaces of a busbar piece. In the present invention, by designing the first soldering portion protruding from a battery bottom housing, the busbar is in better contact with the bottom surface of the first soldering portion, that is, a soldering plane, thereby preventing a gap from existing between the first soldering portion and the busbar, reducing the phenomenon of pseudo soldering, and improving the soldering yield.

Description

A power battery casing Technical Field

[0001] This invention relates to the field of batteries, specifically a power battery casing. Background Technology

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage. A lithium-ion power battery generally includes an internal structure and an external structure. The internal structure mainly includes electrode arrays, while the external structure mainly includes a cover and a casing. The casing provides space for the electrode arrays, and the cover and casing are welded together to fix the electrode arrays within the internal space. Currently, when assembling lithium-ion batteries into packs, busbars are used to connect different cells together. In existing technologies, the two welding points between the individual cell and the busbar are located on the top cover and the bottom cover of the individual cell, respectively. Because the bottom cover is a planar structure, gaps may exist between the busbar and the bottom cover during welding, leading to incomplete welds and weak welds, posing potential safety hazards. Summary of the Invention

[0003] The purpose of this invention is to provide a power battery casing to solve the problems of incomplete welding and weak welding in the prior art, and this invention can improve the safety of the battery.

[0004] To achieve the above objectives, the technical solution of the present invention is: a power battery casing, comprising a side wall and a bottom wall, wherein the side wall and the bottom wall are fixedly connected or integrally formed to form a cavity structure that accommodates a battery cell with one end open; the bottom wall comprises a structural portion and a first welding portion and a plurality of second welding portions distributed on the structural portion; the bottom surface of the first welding portion is lower than the plane where the bottom surface of the structural portion is located; the first welding portion is welded to a busbar; and the second welding portions are welded to one of the tabs or one end face of the battery cell.

[0005] Furthermore, the first welded portion is located at the center of the structural portion, and the second welded portion is distributed around the first welded portion.

[0006] Furthermore, the thickness of the first welded portion is greater than or equal to the thickness of the structural portion, and the first welded portion is a protruding structure formed by a local outward protrusion of the structural portion.

[0007] Furthermore, the thickness of the second welded portion is less than or equal to the thickness of the structural portion, and the second welded portion is a groove-shaped structure formed by a local inward recess of the structural portion.

[0008] Furthermore, an explosion-proof valve is provided on the bottom wall of the shell.

[0009] Furthermore, the explosion-proof valve is provided with explosion-proof markings, which are located on the inner or outer surface of the explosion-proof valve.

[0010] Furthermore, the front projection of the explosion-proof valve does not interfere with the front projection of the manifold.

[0011] Compared with the prior art, the advantages and positive effects of the present invention are as follows: The present invention, by designing a first welding part that protrudes from the bottom shell of the battery, facilitates better contact between the busbar and the bottom surface of the first welding part, i.e., the welding plane, preventing gaps between the first welding part and the busbar, reducing the phenomenon of incomplete welding, and improving the welding yield.

[0012] The first welding part of the battery bottom shell of this invention has a simple structure. Compared with the traditional battery method that requires a separate terminal post to be designed at the bottom of the shell for connecting the busbar, the structure is extremely simple, with fewer production steps and lower cost. Compared with the same-side outlet tab, the method of directly welding the busbar at the bottom results in a shorter circuit path, lower internal resistance, and improved product performance.

[0013] The front projection of the explosion-proof valve and the front projection of the manifold of the present invention do not interfere with each other. The explosion-proof valve and the manifold are staggered to prevent the explosion-proof valve from impacting the manifold when it bursts open. The gas will not be blocked by the manifold when depressurizing, thus achieving better depressurization and improving battery safety. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 is a schematic diagram of the structure of the present invention;

[0016] Figure 2 is a bottom view of the present invention;

[0017] Figure 3 is a cross-sectional view at point AA in Figure 2 of the present invention;

[0018] Figure 4 is an enlarged view of section B in Figure 3 of the present invention;

[0019] Figure 5 is a schematic diagram of the present invention being welded to the battery cell and busbar.

[0020] In the diagram: 1. Bottom wall of the shell; 11. Structural part; 111. First welded part; 112. Second welded part; 113. Explosion-proof valve; 1131. Explosion-proof groove; 2. Side wall of the shell; 3. Busbar; 4. Battery cell. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] As shown in Figures 1-5, a power battery casing includes a side wall 2 and a bottom wall 1. The side wall 2 and the bottom wall 1 are integrally stamped to form a cavity structure with one end open to accommodate the battery cell. Alternatively, the side wall 2 and the bottom wall 1 can also be fixedly connected together by welding.

[0023] To improve welding yield and convenience, the bottom wall 1 of the shell includes a structural part 11 and a first welding part 111 and three second welding parts 112 distributed on the structural part 11. The first welding part 111 is a protruding structure formed by a partial outward protrusion of the structural part 11. The bottom surface of the first welding part 111 is lower than the plane where the bottom surface of the structural part 11 is located. The first welding part 111 is welded to the busbar 3 through the bottom surface of the protruding structure. The protruding structure of the first welding part 111 can facilitate better contact between the busbar 3 and the bottom surface of the first welding part 111, that is, the welding plane, reducing the phenomenon of incomplete welding and improving welding yield.

[0024] In this embodiment, in order to further improve the welding yield, the thickness of the first welding part 111 is greater than or equal to the thickness of the structural part 11 to prevent burn-through.

[0025] In this embodiment, the first welding part 111 is located at the center of the structural part 11 and is positioned between the busbar 3 and the first welding part 111, which facilitates subsequent welding work. Three second welding parts 112 are distributed around the first welding part 111. The second welding parts 112 are welded to one of the tabs of the battery cell 4. In some other embodiments, if a busbar is also provided between the bottom wall 1 of the casing and the battery cell 4, the second welding part 112 is welded to one end face of the busbar, and the other end face of the busbar is welded to one of the tabs of the battery cell 4.

[0026] In this embodiment, in order to facilitate welding, the thickness of the second welding part 112 is less than or equal to the thickness of the structural part 11. The second welding part 112 is a groove-shaped structure formed by a partial inward recess of the structural part 11. Therefore, the side of the second welding part 112 located on the inner side of the bottom wall 1 of the shell can be better welded to one of the tabs of the battery cell 4 or one end face of the busbar.

[0027] In this embodiment, to improve safety, an explosion-proof valve 113 is provided on the bottom wall 1 of the casing, and an explosion-proof groove 1131 is provided on the explosion-proof valve 113. When the explosion-proof valve 113 bursts open, it can burst along the explosion-proof groove 1131, reducing the risk of tearing the casing and further improving the safety performance of the battery cell. In terms of the design of the position of the explosion-proof groove 1131, the explosion-proof groove 1131 can be located on the inner surface or the outer surface of the explosion-proof valve 113.

[0028] In this embodiment, in order to prevent the explosion-proof valve 113 from impacting the manifold 3 when it bursts open, and also to ensure that the gas is not blocked by the manifold 3 during depressurization and achieve better depressurization, the front projection of the explosion-proof valve 113 and the front projection of the manifold 3 do not interfere with each other.

[0029] Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc., made by all other embodiments obtained by those skilled in the art without creative effort should be included within the protection scope of the present invention.

Claims

1. A power battery casing, comprising a side wall and a bottom wall, wherein the side wall and the bottom wall are fixedly connected or integrally formed to form a cavity structure that accommodates a battery cell with one end open, characterized in that: The bottom wall of the shell includes a structural part and a first welded part and several second welded parts distributed on the structural part; The bottom surface of the first welded part is lower than the plane where the bottom surface of the structural part is located, and the first welded part is welded to the busbar; The second welding part is welded to one of the tabs of the battery cell or one of the end faces of the busbar.

2. The power battery casing according to claim 1, characterized in that: The first welded part is located at the center of the structural part, and the second welded part is distributed around the first welded part.

3. The power battery casing according to claim 1, characterized in that: The thickness of the first welded part is greater than or equal to the thickness of the structural part, and the first welded part is a convex structure formed by a local outward protrusion of the structural part.

4. The power battery casing according to claim 1, characterized in that: The thickness of the second welded part is less than or equal to the thickness of the structural part, and the second welded part is a groove-shaped structure formed by a local inward recess of the structural part.

5. The power battery casing according to claim 1, characterized in that: An explosion-proof valve is installed on the bottom wall of the shell.

6. The power battery casing according to claim 5, characterized in that: The explosion-proof valve is provided with explosion-proof markings, which are located on the inner or outer surface of the explosion-proof valve.

7. The power battery casing according to any one of claims 1 or 5, characterized in that: The front projection of the explosion-proof valve does not interfere with the front projection of the manifold.

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