Flattened Wound Electrode Assembly Separator Positioning
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Solution Overview
Problem
Conventional methods for manufacturing energy storage devices with electrode assemblies formed by winding plates and separators are inefficient due to the need for complex operations like thermal fusion bonding of separator end portions, which can lead to defects such as minute short-circuiting and reduced yield.
Innovation Solution
The energy storage device incorporates an electrode assembly with a flattened inner periphery having bent portions on opposite sides, where the end edge of the plate is positioned at one bent portion or nearby, suppressing separator floating and contaminant intrusion by eliminating the need for thermal bonding of adjacent separators and reducing the risk of short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal fusion bonding is used to bond end portions of two separators, then contaminant intrusion is prevented, but manufacturing complexity and time increase
Solution Approach 1:
The invention extracts and eliminates the thermal fusion bonding step from the manufacturing process. Instead of bonding separator end portions, the patent uses a single separator with an extended end portion that is folded back and secured, removing the need for complex thermal bonding operations between two separators while maintaining contaminant prevention functionality
Solution Approach 2:
Instead of bonding two separate separator end portions together (conventional approach), the invention inverts the approach by using one separator whose end portion is extended, folded back, and secured to the battery case or electrode assembly, thereby preventing contaminant intrusion without requiring thermal fusion bonding between two separators
2Stability of the object's composition
If thermal fusion bonding is used to bond separator end portions, then separator stability is improved, but manufacturing time and efficiency deteriorate
Solution Approach 1:
The separator is designed with an extended end portion that is folded back and secured during the winding process itself, rather than requiring a separate thermal fusion bonding step after winding. This preliminary integration of the stabilization function into the winding process improves manufacturing efficiency while maintaining separator stability
Solution Approach 2:
The separator structure itself provides the stabilization function through its extended and folded-back end portion, which is secured to the battery case or electrode assembly. This self-contained design eliminates the need for external thermal fusion bonding operations, thereby improving manufacturing efficiency while maintaining structural stability
3Manufacturing precision
If complex bonding operations are performed, then separator positioning precision is improved, but manufacturing complexity increases
Solution Approach 1:
The invention extracts the complex thermal fusion bonding operation from the manufacturing process and replaces it with a simpler method of folding back and securing the extended separator end portion, thereby maintaining positioning precision while reducing operational complexity
Solution Approach 2:
The invention changes the structural parameter of the separator by extending its end portion and folding it back, transforming the positioning method from thermal bonding to mechanical securing, thereby simplifying the bonding operation while maintaining positioning precision
Data Source
AI summary
An energy storage device includes an electrode assembly formed by winding a negative electrode plate, a separator and the like. An innermost periphery of the negative electrode plate, the separator and the like which are wound together has a flattened shape having a pair of bent portions disposed on opposite sides in a first direction as viewed in a direction of the winding axis, and an end edge of the negative electrode plate on an innermost periphery side is disposed at one bent portion out of the pair of bent portions or a position in the vicinity of the one bent portion.