US-12617048-B2 - Welding apparatus including electrode tab fixing portion

US12617048B2US 12617048 B2US12617048 B2US 12617048B2US-12617048-B2

Abstract

A welding apparatus may include an electrode tab fixing portion capable of maintaining the distance between and the shape of electrode tabs while minimizing damage to electrode tabs when welding the electrode tabs.

Inventors

Gil Sang Son
Jin Hak KONG
Dong Yeon Kim
Kyu Hyun Choi

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260505
Application Date: 20210823
Priority Date: 20201021

Claims (12)

1 . A welding apparatus comprising: a tab guide assembly configured to gather a plurality of electrode tabs protruding from an electrode assembly to form a single tab bundle; a welding jig configured to weld the single tab bundle; and an electrode tab fixing assembly configured to be disposed between the electrode assembly and the tab guide assembly, the electrode tab fixing assembly being configured to maintain a space between the electrode tabs of the single tab bundle, the electrode tab fixing assembly comprising left and right fixing portions configured to be disposed between adjacent ones of the electrode tabs at left and right opposite lateral sides of each of the electrode tabs, respectively, wherein the left and right opposite lateral sides of the electrode tabs extend away from the electrode assembly in an extension direction of the electrode tabs, and wherein the left and right fixing portions are separable from one another and removable from the single tab bundle after welding.
2 . The welding apparatus according to claim 1 , wherein the electrode tab fixing assembly comprises: insertion portions configured to be inserted between adjacent ones of the electrode tabs; and a body portion coupled to the insertion portions, the body portion maintaining the insertion portions spaced apart from each other therein.
3 . The welding apparatus according to claim 2 , wherein the insertion portions are configured to be inserted between the electrode tabs parallel to the electrode tabs.
4 . The welding apparatus according to claim 3 , wherein the insertion portions are configured to be inserted between the electrode tabs in a tight-fitting manner.
5 . The welding apparatus according to claim 1 , wherein the welding apparatus is configured such that the electrode tab fixing assembly is configured to be disposed closer to the tab guide assembly than the electrode assembly.
6 . The welding apparatus according to claim 1 , wherein the tab guide assembly comprises: an upper tab guide configured to press against the electrode tabs from a position above the electrode tabs; and a lower tab guide configured to press against the electrode tabs from a position under the electrode tabs.
7 . The welding apparatus according to claim 6 , wherein the upper tab guide and the lower tab guide are configured to press the electrode tabs partially facing each other and oriented parallel to one another while forming the single tab bundle.
8 . The welding apparatus according to claim 1 , wherein a portion of the tab guide assembly that faces the electrode tabs is curved.
9 . The welding apparatus according to claim 8 , wherein the portion of the tab guide assembly that faces the electrode tabs has an inclined curve shape configured such that when the tab guide assembly is disposed adjacent to the electrode tabs, a portion of the tab guide assembly farthest from the electrode assembly is closest to the electrode tabs.
10 . The welding apparatus according to claim 1 , wherein the welding jig is configured to perform welding using ultrasonic waves.
11 . The welding apparatus according to claim 10 , wherein the welding jig includes a horn and an anvil.
12 . The welding apparatus according to claim 1 , wherein the welding jig is configured to weld a portion of the single tab bundle farthest from the electrode assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/KR2021/011177, filed on Aug. 23, 2021, which claims priority to Korean Patent Application No. 10-2020-0136428, filed on Oct. 21, 2020, the disclosures of which are hereby incorporated herein by reference in their entireties. The present invention relates to a welding apparatus including an electrode tab fixing portion and an electrode tab welding method using the same, and more particularly to a welding apparatus including a tab guide configured to gather electrode tabs and an electrode tab fixing portion configured to prevent damage to the electrode tabs when the electrode tabs are gathered by the tab guide and an electrode tab welding method using the same. BACKGROUND ART With recent diversification of devices that use batteries, demand for high-capacity and high-density batteries has increased. Thereamong, a lithium secondary battery, which has high energy density and discharge voltage, has been commercialized and used in various forms. As an example, secondary batteries are classified into a cylindrical secondary battery, a prismatic secondary battery, and a pouch-shaped secondary battery depending on the shape thereof. In addition, a secondary battery may have a structure in which an electrode assembly is received in any one of various cases. The electrode assembly may be a jelly-roll type assembly, which is configured to have a structure in which a long sheet type positive electrode and a long sheet type negative electrode are wound in the state in which a separator is interposed therebetween, a stacked type assembly which is configured to have a structure in which a rectangular positive electrode and a rectangular negative electrode are stacked in the state in which a separator is interposed therebetween, a stacked and folded type assembly, which is configured to have a structure in which unit cells are wound using a long separation film, or a laminated and stacked type assembly, which is configured to have a structure in which unit cells are stacked and attached to each other in the state in which a separator is interposed therebetween. Thereamong, an electrode assembly configured to have a structure in which one or more positive electrodes and one or more negative electrodes are stacked, such as a stacked type assembly, a stacked and folded type assembly, or a laminated and stacked type assembly, is preferred for reasons that the capacity of the electrode assembly compared to the density thereof is increased, the electrode assembly is easily manufactured, and the shape of the electrode assembly is easily changed. In the stacked type electrode assembly, electrode tabs protruding from the electrode assembly are gathered and welded to an electrode lead, which is electrically connected to the outside. FIG. 1 is a schematic view of a stacked type electrode assembly before being pressed by a conventional welding apparatus, and FIG. 2 is a schematic view of the stacked type electrode assembly after being pressed by the conventional welding apparatus. As can be seen from FIGS. 1 and 2, the conventional welding apparatus welds an electrode assembly 10 and a plurality of electrode tabs 11 protruding from the electrode assembly 10. The electrode assembly 10 may be any one of a stacked type assembly, a stacked and folded type assembly, and a laminated and stacked type assembly. The electrode tabs 11 are gathered by a tab guide 20 to form a tab bundle 12, and the tab bundle is pressed and welded through a welding jig 30 constituted by a horn 31 and an anvil 32. The horn 31 and the anvil 32 apply high-frequency vibration generated by an ultrasonic wave having a high frequency of about 20 kHz, and vibration energy is converted into thermal energy between the electrode tabs 11 and an electrode lead, whereby rapid welding is performed therebetween. However, ultrasonic welding using vibration energy may shock the electrode assembly 10, the electrode tabs 11, and the electrode lead, and cutting of the electrode tabs 11 or between the electrode tabs 11 and the electrode lead may be caused. In order to prevent this, the conventional welding apparatus secures a relatively long length of the electrode tabs 11 through the tab guide 20. The tab guide 20 may be constituted by at least two tab guides, such as an upper tab guide 21 and a lower tab guide 22, and the length of the electrode tabs 11 may be secured using one tab guide 20. When the electrode tabs 11 are gathered while being pressed by the tab guide 20, however, the electrode tabs 11 may be damaged, or the electrode tabs 11 may be cut at the portion of the electrode tabs at which the electrode tabs are gathered by the tab guide 20. In particular, when the electrode tabs 11 are pressed at a steep angle, a danger of the electrode tabs 11 being cut is further increased. In Patent Document 1, an electrode tab is pressed such that