EP-4738600-A1 - BATTERY CELL, ASSEMBLY METHOD FOR BATTERY CELL, AND BATTERY PACK

EP4738600A1EP 4738600 A1EP4738600 A1EP 4738600A1EP-4738600-A1

Abstract

A battery cell (1), a method for assembling the battery cell (1), and a battery pack are provided. In the battery cell (1), a tab (22) in an electrode assembly (20) extends in a first direction (X) without bending. A connecting sheet (31) is provided on an end surface (2221) of a second end (222) of a tab (22) exposed from a main body (21), and the connecting sheet (31) is welded to the end surface (2221) of the second end (222) to form a welding mark (32) extending in a second direction (Y). The tab (22) only needs to be exposed from the main body (21) by a short distance to achieve connection with the connecting sheet (31), thereby increasing the capacity of the battery cell (1) and enhancing the energy density of the battery cell (1).

Inventors

YANG, WEI
ZHANG, MENG

Assignees

Sunwoda Mobility Energy Technology Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20240520

Claims (15)

A battery cell, comprising: a housing having an accommodating cavity; wherein the battery cell further comprises: an electrode assembly, provided in the accommodating cavity, and comprising a main body and a tab connected to the main body; the main body has a first direction, and the tab extends only along the first direction; the tab has a second end, and the second end is located on a side of the tab away from the main body; a connecting assembly, provided on a side of the second end away from the main body, and fixed to an end surface of the second end by welding; a welding mark is formed at a welding position between the connecting assembly and the end surface of the second end; at least part of the welding mark penetrates the connecting assembly and partially extends along the first direction into the second end of the tab; the tab comprises a plurality of tab sheets stacked along a second direction, and the welding mark is arranged along the second direction; wherein the first direction intersects with the second direction; the housing is provided with an opening, and a side of the main body facing the opening has a mounting surface perpendicular to the first direction; in the first direction, a distance between the end surface of the second end of the tab and the mounting surface is L, wherein 0.1 mm ≤ L ≤ 10 mm.
The battery cell according to claim 1, wherein 0.5 mm ≤ L ≤ 5 mm.
The battery cell according to claim 1, wherein the housing is provided with the opening, and the side of the main body facing the opening has the mounting surface perpendicular to the first direction; an orthographic projection of the welding mark onto the mounting surface has two maximum contour points opposite to each other in the second direction, and a line segment extending along the second direction is provided between the two maximum contour points; a length L 1 (mm) of the line segment is a maximum dimension of the orthographic projection of the welding mark onto the mounting surface in the second direction; the housing comprises two side walls opposite to each other along the second direction, and a distance between the two side walls in the second direction is L 2 (mm), satisfying: 0.5 ≤ L 1 /L 2 < 1.
The battery cell according to claim 3, wherein 0.6 ≤ L 1 /L 2 ≤ 0.95.
The battery cell according to claim 1, wherein the connecting assembly comprises a connecting sheet and a terminal; the connecting sheet comprises a first segment and a second segment connected along a third direction, and the first segment is fixed to the end surface of the second end by welding; the terminal is provided on a surface of the second segment away from the main body in the first direction, and the terminal is electrically connected to the tab through the connecting sheet; the first direction, the second direction, and the third direction are perpendicular to each other.
The battery cell according to claim 5, wherein the welding mark is formed at a welding position between the connecting sheet and the end surface of the second end, and at least part of the welding mark penetrates the connecting sheet along the first direction, and partially extends into the second end of the tab; in the first direction, the connecting sheet has a thickness of H 1 mm, and the welding mark has a depth of H 2 mm, satisfying: 0.5 mm+H 1 ≤H 2 ≤1.5 mm+H 1 .
The battery cell according to claim 5, wherein the housing has the opening connecting the accommodating cavity to the outside; the battery cell further comprises a top cover plate and a baffle plate, and the top cover plate covers the opening of the housing; the top cover plate is provided with a first through-hole and a second through-hole arranged spaced apart along the third direction, and the terminal is inserted into the first through-hole; the second through-hole is provided opposite to the second end of the tab along the first direction, and the baffle plate is provided within the second through-hole, wherein the first direction, the second direction, and the third direction are perpendicular to each other.
The battery cell according to claim 7, wherein the battery cell further comprises an insulating sheet provided between the baffle plate and the first segment to electrically insulate the connecting sheet from the baffle plate.
The battery cell according to claim 1, wherein a shape of the welding mark comprises at least one of a circle, an arc, an oblique line, and a polyline.
The battery cell according to claim 9, wherein the welding mark has a shape of an oblique line, each connecting sheet is provided with a plurality of welding mark units, and the plurality of welding mark units form the welding mark; and an angle is formed between a length direction of each welding mark unit and the second direction, and the angle is within a range of 10°-80°.
The battery cell according to claim 3, wherein a preset angle α is formed between the line segment and the third direction, and the preset angle α satisfies: 0° < α ≤ 90°.
The battery cell according to claim 11, wherein the preset angle α satisfies: 85° ≤ α ≤90°.
A method for assembling the battery cell according to any one of claims 1-12, comprising the following steps: inserting the electrode assembly into the housing, wherein the second end of the tab of the electrode assembly in the first direction faces the opening of the housing; welding at least part of the end surface of the second end of the tab with the connecting sheet to form the welding mark, wherein the welding mark extends along the second direction.
A battery pack, wherein the battery pack comprises the battery cell according to any one of claims 1-12.
A battery pack, wherein the battery pack comprises the battery cell assembled by the method for assembling the battery cell according to claim 13.

Description

The present application claims priority to Chinese patent application No. 202311010207.2 filed with China National Intellectual Property Administration on August 11, 2023, and entitled "Battery Cell, Method for Assembling Battery Cell, and Battery Pack", which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present application relates to the technical field of batteries, in particular to a battery cell, a method for assembling the battery cell, and a battery pack. BACKGROUND In existing battery cells, tabs of a cell generally protrude from a main body of the cell along a third direction of the cell. To connect with adapter sheets, the tabs extending along the third direction needs to be bent, and the bent tabs are connected to the adapter sheets. This will increase the bending process, affecting the assembly efficiency of the battery cell. TECHNICAL SOLUTION In a first aspect, the present application provides a battery cell, including: a housing having an accommodating cavity; where the battery cell further includes: an electrode assembly, provided in the accommodating cavity and including a main body and a tab connected to the main body, where the main body has a first direction, and the tab extends only along the first direction, the tab includes a second end, and the second end is located on a side of the tab away from the main body; a connecting assembly, provided on a side of the second end away from the main body and fixed to an end surface of the second end by welding, where a welding mark is formed at a welding position between the connecting assembly and the end surface of the second end, at least part of the welding mark penetrates the connecting assembly and partially extends along the first direction into the second end of the tab, the tab includes a plurality of tab sheets stacked along the second direction, and the welding mark is arranged along the second direction, where the first direction intersects with the second direction; the housing is provided with an opening, and a side of the main body facing the opening has a mounting surface perpendicular to the first direction; in the first direction, a distance between the end surface of the second end of the tab and the mounting surface is L, where 0.1 mm ≤ L ≤ 10 mm. Optionally, 0.5 mm ≤ L ≤ 5 mm. Optionally, the housing is provided with the opening, and the side of the main body facing the opening has the mounting surface perpendicular to the first direction; a orthographic projection of the welding mark onto the mounting surface has two maximum contour points opposite to each other in the second direction, and a line segment extending along the second direction is provided between the two maximum contour points; a length L1 (mm) of the line segment is a maximum dimension of the orthographic projection of the welding mark onto the mounting surface in the second direction; the housing includes two side walls opposite to each other along the second direction, and a distance between the two side walls in the second direction is L2 (mm), satisfying: 0.5 ≤ L1/L2 < 1. Optionally, 0.6 ≤ L1/L2 ≤ 0.95. Optionally, the connecting assembly includes a connecting sheet and a terminal; the connecting sheet includes a first segment and a second segment connected along a third direction, and the first segment is fixed to the end surface of the second end by welding; the terminal is provided on a surface of the second segment away from the main body in the first direction, and the terminal is electrically connected to the tab through the connecting sheet; the first direction, the second direction, and the third direction are perpendicular to each other. Optionally, the welding mark is formed at a welding position between the connecting sheet and the end surface of the second end, and at least part of the welding mark penetrates the connecting sheet along the first direction, and partially extends into the second end of the tab; in the first direction, the connecting sheet has a thickness of H1 mm, and the welding mark has a depth of H2 mm, satisfying: 0.5 mm + H1 ≤ H2 ≤ 1.5 mm + H1. Optionally, the housing has the opening connecting the accommodating cavity to the outside; the battery cell further includes a top cover plate and a baffle plate, and the top cover plate covers the opening of the housing; the top cover plate is provided with a first through-hole and a second through-hole arranged spaced apart along the third direction, and the terminal is inserted into the first through-hole; the second through-hole is provided opposite to the second end of the tab along the first direction, and the baffle plate is provided within the second through-hole, where the first direction, the second direction, and the third direction are perpendicular to each other. Optionally, the battery cell further includes an insulating sheet provided between the baffle plate and the first segment to electrically insulate the connecting sheet from the baff