Bellow-Folded Insulating Holder for Battery Case Short-Circuit Prevention
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Solution Overview
Problem
Existing electricity storage devices face challenges in preventing short-circuiting between the electrode body and the metal case due to direct contact, which necessitates the use of multiple insulating components, increasing costs.
Innovation Solution
An insulating holder formed by folding a sheet with a bellow-folded structure is used to accommodate the electrode body, providing reliable insulation between the electrode body and the case, thereby reducing the need for multiple insulating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple insulating components (insulating holder and press-contact member or bottom retainer) are used to prevent short-circuiting, then reliability of insulation is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the insulating holder and press-contact member (or bottom retainer) into a single integrated insulating holder structure. The insulating holder is designed with protruding portions that extend toward the electrode body, integrating both the insulation function and the press-contact function into one component, thereby reducing the total number of parts while maintaining reliable insulation and preventing short-circuiting
Solution Approach 2:
The insulating holder is designed to perform multiple functions simultaneously: it provides electrical insulation between the electrode body and case, maintains the tensioned state of the electrode assembly through its protruding portions, and prevents short-circuiting. This multi-functional design eliminates the need for separate press-contact members or bottom retainers, reducing device complexity while maintaining reliability
2Reliability
If a rigid insulating holder is used to maintain insulation, then insulation reliability is improved, but stress concentration on the electrode body occurs
Solution Approach 1:
The insulating holder features localized soft portions at specific contact areas where it interfaces with the electrode body. These soft portions are positioned precisely where contact occurs, allowing them to absorb stress and prevent concentration on the electrode body, while the rest of the holder maintains its rigid structure to ensure reliable insulation
Solution Approach 2:
The insulating holder is constructed using composite material properties, combining rigid regions for structural support and insulation with localized soft portions for stress absorption. This composite structure allows the holder to simultaneously maintain insulation reliability and prevent stress concentration on the electrode body
Data Source
AI summary
An electricity storage device includes: an electrode body including at least one positive electrode plate, at least one negative electrode plate, and a separator. an insulating holder that is formed by folding a sheet made of an insulating material and accommodates therein the electrode body; an outer case which has an opening and accommodates therein the electrode body with the insulating holder and an electrolyte; and a sealing plate. The outer case has a bottom plate part and a plurality of side walls standing from the bottom plate part, and the opening is formed in a position to face the bottom plate part. The insulating holder has a plurality of side surface parts respectively facing the plurality of side walls, and a bottom surface part that faces the bottom plate part. At least one of the side surface parts or the bottom surface part has a bellow-folded structure.