CN-116014322-B - Secondary battery

Abstract

A secondary battery includes an electrode body, a battery case including a case body and a cover, an external terminal, and a gasket for insulating the cover from the external terminal outside the battery case. The cover has a mounting hole for mounting the external terminal. The external terminal has a shaft portion inserted into the mounting hole, and a head portion disposed outside the battery case and extending in an outer diameter direction from one end of the shaft portion. The gasket has a support portion disposed between the bottom surface of the head and the cover, and a side wall standing upward from the support portion. The head has a chamfered portion that is chamfered in at least a portion of the outer periphery of the bottom surface. A gap is formed between the chamfer portion, the support portion and the side wall.

Inventors

• Yoneda Yukishiro

Assignees

• 泰星能源解决方案有限公司

Dates

Publication Date

20260512

Application Date

20221019

Priority Date

20211022

Claims (6)

1. 1. A secondary battery is provided with: An electrode body; A battery case including a case body having an opening and a cover closing the opening of the case body; An external terminal electrically connected to the electrode body and exposed to the outside of the battery case, and A spacer insulating the cover and the external terminal at the outside of the battery case, wherein, The cover has a mounting hole for mounting the external terminal, The external terminal has a shaft portion inserted into the mounting hole and a head portion disposed outside the battery case and extending in an outer diameter direction from one end of the shaft portion, The gasket has a supporting portion arranged between the head portion and the cover, and a side wall standing upward from the supporting portion, The head portion of the external terminal has: A flat bottom surface along the support portion of the gasket; a side peripheral surface surrounded by the side wall of the gasket, and A chamfer portion chamfered between the bottom surface and the side peripheral surface, A gap is formed between the chamfer portion, the support portion and the side wall, The gasket compresses the thickness of the supporting part to a compression ratio of more than 50% through the bottom surface of the head part and the cover, The side wall is inclined toward the side peripheral surface of the head portion.
2. 2. The secondary battery according to claim 1, wherein, The chamfer portion is C-shaped or R-shaped.
3. 3. The secondary battery according to claim 1, wherein, The cover has a continuous protrusion in the circumferential direction at a position overlapping the chamfer portion with the support portion of the gasket interposed therebetween, The support portion of the gasket is compressed by the protrusion of the cover and the chamfer portion.
4. 4. The secondary battery according to any one of claim 1 to 3, wherein, The chamfer is continuously provided in the circumferential direction of the head.
5. 5. The secondary battery according to any one of claim 1 to 3, wherein, The cover is of rectangular shape and, The chamfer is provided along the longitudinal direction of the cover.
6. 6. The secondary battery according to any one of claim 1 to 3, wherein, The cover is of rectangular shape and, The side wall of the gasket has a portion of 1.8mm or less from a peripheral edge portion of the cover.

Description

Secondary battery Technical Field The present invention relates to a secondary battery. Background Japanese patent application laid-open No. 2008-270167 discloses a sealed battery including an electrode external terminal having a flange portion and a columnar insertion portion, an insulating gasket, and a sealing plate. In the sealed battery disclosed in this publication, the cross section of the columnar insertion portion of the electrode external terminal is a non-perfect circle (non-complete circular shape). Thus, the columnar insertion portion is not easily rotated, and liquid leakage due to rotation of the electrode external terminal is not easily generated. Japanese patent application laid-open No. 2008-192552 discloses an electrode including a metal rivet serving as a conduction portion extending from the inside of a battery case and having an end enlarged by caulking at the outside, and a metal terminal having a portion provided with a through hole, the metal terminal being fixed to the battery case by penetrating the rivet through the through hole. The electrode is insulated from the cover by an insulator. In the electrode disclosed in this publication, at least the front end side of the rivet of the through hole of the metal terminal is a tapered hole that expands toward the front end side of the rivet. This can alleviate stress concentration on the rivet distal end side of the fixed electrode. Prior art literature Patent document 1 Japanese patent application laid-open No. 2008-270167 Patent document 2 Japanese patent application laid-open No. 2008-192552 Disclosure of Invention The external terminal exposed to the outside of the battery case is attached to the lid of the battery case via a spacer. The gasket has a sealing function of ensuring the air tightness inside the battery case, and an insulating function of the external terminal and the cover. For example, when a high voltage, a high temperature, a high pressure, or the like is applied to the gasket, the gasket may be damaged, and the sealing function, the insulating function, or the like may be impaired. The present inventors considered that it is desirable to propose a structure of a secondary battery that suppresses damage to a gasket. The secondary battery disclosed herein includes an electrode body, a battery case having a case body and a cover, the case body having an opening, the cover closing the opening of the case body, an external terminal electrically connected to the electrode body and exposed to the outside of the battery case, and a gasket insulating the cover from the external terminal at the outside of the battery case. The cover has a mounting hole for mounting the external terminal. The external terminal has a shaft portion inserted into the mounting hole, and a head portion disposed outside the battery case and extending in an outer diameter direction from one end of the shaft portion. The gasket has a support portion disposed between the bottom surface of the head and the cover, and a side wall standing upward from the support portion. The head portion of the external terminal has a chamfered portion that is chamfered in at least a portion of the outer periphery of the bottom surface. A gap is formed between the chamfer portion, the support portion, and the side wall. With the above structure, damage to the gasket is suppressed. The chamfer may be C-shaped or R-shaped. The gasket may have a portion where the thickness of the support portion is compressed to a compression ratio of 50% or more on a surface in contact with the bottom surface of the head portion. The chamfer may be continuously provided in the circumferential direction of the head. The cover may also be rectangular in shape. The chamfering portion may be provided along the longitudinal direction of the cover. The side wall of the gasket may have a portion of 1.8mm or less from the peripheral edge portion of the cover. Drawings Fig. 1 is a partial sectional view of a lithium ion secondary battery 10. Fig. 2 is a plan view showing a positional relationship between the cover 41b and the external terminal 61. Fig. 3 is a section view of fig. 1 in section III-III. Fig. 4 is a cross-sectional view schematically showing the shapes of the head 63 and the pad 70 of the external terminal 61. Fig. 5 is a cross-sectional view schematically showing the shapes of the external terminal 161 and the spacer 170 where no chamfer is provided. Fig. 6A is a cross-sectional view schematically showing the shape of the head 63 of the other embodiment. Fig. 6B is a cross-sectional view schematically showing the shape of the head 63 of the other embodiment. Detailed Description Hereinafter, an embodiment of the secondary battery disclosed herein will be described. The embodiments described herein are obviously not intended to be particularly limiting of the invention. The drawings are schematically drawn and do not necessarily reflect actual objects. The terms "A-B" and the like re