Battery Cell Connecting Structure for Separator Shrinkage Control
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Solution Overview
Problem
Existing lithium-ion batteries face safety issues due to separator shrinkage during impacts, leading to short-circuits and potential fires, especially at the tab positions where adhesive tape application is impractical.
Innovation Solution
The battery cell design incorporates a first connecting piece and a second connecting piece that surround the respective end faces of the electrode assembly, featuring via holes to secure the tab and prevent separator shrinkage, while additional connecting pieces ensure fixation and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pieces of adhesive tape are affixed to the head and end of the electrode assembly, then the separator at the head and end is prevented from shrinking, but the separator in the gaps between adhesive tape pieces and at the tab position is not fastened and remains prone to shrinkage
Solution Approach 1:
The connection structure is divided into multiple segments: first connecting piece at the head, second connecting piece at the end, and third connecting piece at the tab position. Each segment independently fastens the separator in its specific region, ensuring comprehensive coverage without gaps and preventing separator shrinkage at all critical positions.
Solution Approach 2:
Different connecting pieces are strategically positioned at different locations (head, end, and tab) with different structural characteristics. The third connecting piece specifically addresses the tab position where adhesive tape cannot be applied, providing localized protection where it is most needed.
2Reliability
If adhesive tape is used to fasten the separator, then the separator is prevented from shrinking at the head and end, but adhesive tape cannot be applied at the tab position, leaving the separator there unprotected
Solution Approach 1:
The third connecting piece acts as an intermediary structure that bridges the tab and the separator. It provides a mechanical fastening solution for the separator at the tab position, replacing the adhesive tape method that cannot be applied there, thereby extending protection to previously unprotected areas.
3Device complexity
If the separator is not fastened at the tab position, then the structure remains simple, but the separator is prone to shrinkage causing short-circuit and fire hazards
Solution Approach 1:
The third connecting piece is pre-installed at the tab position to fasten the separator before any potential shrinkage can occur. This preliminary fastening action prevents the separator from moving or shrinking during battery operation, eliminating the risk of short-circuit and fire hazards before they can manifest.
Data Source
AI summary
A battery cell includes an electrode assembly, a tab, a first connecting piece, and a second connecting piece. The electrode assembly includes a first end face and a second end face that are disposed opposite to each other, and a first surface and a second surface that are connected to the first end face and the second end face respectively. The tab protrudes from first end face. The first connecting piece surrounds the first end face and is connected to the first surface and the second surface separately. A first via hole is made on the first connecting piece. The tab is threaded out of the first via hole. The second connecting piece surrounds the second end face and is connected to the first surface and the second surface separately. A plurality of second via holes are made on the second connecting piece.