Flat Wound Group Vibration Damping via Localized Holding Portions
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Solution Overview
Problem
Secondary cells, such as lithium ion cells, face electrolyte depletion due to expansion and contraction during charge and discharge, leading to increased resistance, and existing spacers are insufficient to prevent vibration and impact-induced damage.
Innovation Solution
A structure that uses insulating sheets with holding portions between the flat wound group and the cell case to stabilize the wound group, reducing vibration and preventing electrolyte depletion by maintaining a gap between the wound group and the case, thereby minimizing the risk of connection breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a holding portion is formed to precisely follow the curved portion of the wound group, then vibration is reduced, but manufacturing complexity increases due to close dimensional tolerance requirements
Solution Approach 1:
The holding portion provides support at specific localized contact points along the curved surface rather than requiring continuous precise conformity. This local quality approach reduces vibration at critical areas while allowing manufacturing tolerances to be more relaxed in non-critical regions.
Solution Approach 2:
The holding portion provides sufficient support at key locations along the curved surface without requiring complete and precise conformity throughout. This partial action approach achieves adequate vibration reduction while simplifying manufacturing by eliminating the need for tight dimensional tolerances across the entire curved surface.
Data Source
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AI summary
Provided is a secondary cell which is resistant to vibration and impact. The secondary cell includes a flat wound group supported, through an insulator, at a lid on which external terminals are arranged, and a cell case for housing the flat wound group. In the secondary cell, a flat portion of the flat wound group has a gap between the flat portion and a wide surface of the cell case, and is held on the wide surface near a cell case bottom through a holding portion.