Chamfered Battery Terminal Head to Protect Gasket Sealing
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Solution Overview
Problem
The gasket in secondary batteries is prone to damage due to high voltage, high temperature, and high pressure, compromising its sealing and insulating functions when positioned near the external terminal and lid, especially when subjected to laser welding.
Innovation Solution
The secondary battery design incorporates a chamfered portion on the external terminal's head, forming a gap between the gasket's bearing portion and side wall, reducing deformation and damage during compression, and enhancing dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gasket is positioned near the external terminal and lid to provide sealing and insulating functions, then the sealing and insulating performance is improved, but the gasket is prone to damage under high voltage, high temperature, and high pressure conditions
Solution Approach 1:
The gasket is designed with different structural zones: a compressed bearing portion for sealing contact and a non-compressed portion with extended height for insulation. This local differentiation allows the gasket to simultaneously achieve sealing reliability and damage resistance by concentrating compression only where needed for sealing while maintaining structural integrity in the insulation region
Solution Approach 2:
The gasket is segmented into functionally distinct regions: a bearing portion for compression and sealing, and a side wall portion for insulation and mechanical support. This segmentation allows each region to be optimized independently - the bearing portion handles sealing loads while the side wall maintains dimensional stability and insulation under harsh conditions
2Device complexity
If the external terminal head is designed without a chamfered portion, then the structure is simpler, but the gasket bearing portion and side wall are prone to deformation and damage during compression
Solution Approach 1:
The chamfered portion is pre-formed on the external terminal head before assembly, creating a gradual transition surface that guides the gasket into proper position and distributes compression forces evenly. This preliminary structural preparation prevents deformation during the compression process and maintains dimensional accuracy without requiring complex post-assembly adjustments
Solution Approach 2:
The chamfered portion acts as a cushioning feature that gradually transitions the compression load from the external terminal to the gasket. This gradual load introduction prevents sudden stress concentration and deformation of the gasket bearing portion and side wall, protecting the structure before full compression is applied
Data Source
AI summary
A secondary battery disclosed here includes; an electrode body; a battery case including a case body and a lid; an external terminal; and a gasket insulates the lid and the external terminal at an outer side of the battery case. The lid has an attachment hole to which the external terminal is attached. The external terminal includes a shaft inserted in the attachment hole and a head extending radially outward from one end of the shaft. The gasket includes a bearing portion disposed between a bottom surface of the head and the lid, and a side wall rising upward from the bearing portion. The head has a chamfered portion in which at least a part of as outer periphery of the bottom surface. A gap is formed between the chamfered portion and each of the bearing portion and the side wall.