Insulating Member for Secondary Battery Electrode Assembly
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Solution Overview
Problem
Rechargeable batteries face challenges with electrode assembly insulation, leading to potential short circuits, irregular expansion, and performance deterioration due to non-uniform interfaces and instability between the electrode assembly and the case.
Innovation Solution
An insulating member with a base and extending plates is used to maintain the shape of the electrode assembly, preventing relative movement and providing a stable interface, while allowing for expansion and contraction, and is made from laminated films like polypropylene and polytetrafluoroethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film is installed between the electrode assembly and the case, then insulation is provided, but the film may be torn apart during installation causing internal short circuit
Solution Approach 1:
The insulating member is divided into a base portion and multiple plate portions extending from it. This segmentation allows the insulating structure to be installed without fragile thin films, as the plate portions can be positioned and fixed more reliably while maintaining insulation functionality.
Solution Approach 2:
The insulating member acts as an intermediary structure between the electrode assembly and the case. It provides insulation through its material properties while its robust plate structure prevents the installation issues associated with thin insulating films.
2Ease of manufacture
If the electrode assembly is pressed into a flat jelly-roll, then it can be housed in the case, but the flat part is thinner and cannot be stably attached to the case interface
Solution Approach 1:
The insulating member extends in the vertical dimension with plate portions that reach up to contact the electrode assembly. This adds a dimensional element that compensates for the thinness of the flat electrode assembly parts, providing stable attachment through the plate-electrode contact interface.
3Adaptability or versatility
If the electrode assembly is allowed to expand and contract freely, then battery operation is maintained, but irregular expansion and contraction deteriorates battery performance
Solution Approach 1:
The insulating member provides different functional qualities at different locations: the base portion provides insulation and structural support at the bottom, while the plate portions extend upward to provide localized support and shape maintenance at the electrode assembly interfaces, allowing controlled expansion while preventing irregular deformation.
4Ease of manufacture
If the electrode assembly has convex edges, then it can be formed by winding, but the flat part is relatively thinner and creates interface instability
Solution Approach 1:
The insulating member's segmented structure with base and plate portions allows it to interface with different parts of the electrode assembly (convex edges and flat parts) separately, compensating for the thickness variation and maintaining uniform interface characteristics.
Data Source
AI summary
A rechargeable battery includes: an electrode assembly including: a positive electrode, a negative electrode and a separator between the positive electrode and the negative electrode that are wound together; a case housing the electrode assembly; a terminal electrically connected to the electrode assembly; and an insulating member installed between the electrode assembly and the case wherein the insulating member has a base and four insulating plates extending from the base.