Electrode Assembly Tape Separator Contraction
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Solution Overview
Problem
Lithium secondary batteries are prone to internal short circuits due to the contraction of the separator, which causes the positive and negative electrode plates to come into contact, especially when exposed to heat or during charge/discharge cycles.
Innovation Solution
Attaching tape to the upper and lower parts of the wound separator or completely covering the end of the separator with tape to prevent contraction and ensure the electrodes remain separated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator is used without additional protective measures, then the battery structure remains simple, but the separator contracts during charge/discharge or thermal impact causing internal short circuits
Solution Approach 1:
The patent introduces an auxiliary tape as an intermediary component attached to the separator. This tape prevents the separator from contracting laterally during charge/discharge cycles or thermal expansion, thereby preventing internal short circuits between positive and negative electrode plates. The tape acts as a mediator that maintains the separator's dimensional stability without fundamentally changing the separator's material properties.
2Reliability
If the tape is attached to completely cover the end of the separator, then the prevention of separator contraction is maximized, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies the tape selectively to specific regions of the separator - particularly to the upper and lower parts of the separator's end - rather than requiring complete coverage of the entire separator. This localized application approach provides sufficient prevention of lateral contraction while reducing the complexity of the manufacturing process compared to complete coverage.
Data Source
AI summary
A secondary battery includes an electrode assembly designed to prevent an internal short circuit. The electrode assembly includes an electrode group formed by stacking and winding a first electrode plate, a separator and a second electrode plate, and a tape is attached to upper and lower parts of an end of the electrode group. An end of the separator is exposed externally, and the tape is attached to upper and lower parts of the end of the separator. Furthermore, a secondary battery having the electrode assembly is provided.