Folded Multi-Layer Separator for Wound Electrode Assemblies
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Solution Overview
Problem
Lithium-ion batteries face issues with short circuits due to lithium dendrite formation and electrode sheet burrs, leading to reduced service life and safety concerns, as existing separating members are prone to puncture and breakage during the winding process.
Innovation Solution
An electrode assembly with a multi-layer separating member, where the second separating member is formed by folding from the end of the first separating member, enhancing the strength and integrity of the separating member, particularly at bending positions, to prevent short circuits and extend battery life and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer separating member is used, then the device complexity is reduced, but the strength and reliability are insufficient leading to puncture and breakage
Solution Approach 1:
The separating member is divided into multiple layers (first separating member and second separating member) with different materials and functions. The first separating member provides basic separation, while the second separating member reinforces strength at critical bending positions, resolving the contradiction between strength and complexity through functional segmentation.
Solution Approach 2:
The second separating member is selectively positioned at bending positions where stress concentration occurs during winding. This local reinforcement approach increases strength where needed without adding complexity throughout the entire separating member structure.
2Reliability
If the separating member is made thicker to prevent breakage, then the reliability is improved, but the material cost and device complexity increase
Solution Approach 1:
Instead of uniformly thickening the separating member, the second separating member is applied locally at bending positions where breakage risk is highest. This maintains reliability by protecting critical areas while minimizing overall material consumption.
Solution Approach 2:
The second separating member extends slightly beyond the immediate bending position to ensure complete coverage of the stress concentration zone. This partial extension provides adequate protection without excessive material usage.
3Strength
If the second separating member is separately provided and fixed, then the strength at bending position is increased, but the manufacturing complexity and time increase
Solution Approach 1:
The second separating member is integrated with the first separating member by folding, eliminating the need for separate fixation processes. This merging of components maintains the strength enhancement while significantly simplifying the manufacturing process and reducing assembly steps.
Solution Approach 2:
The folding structure allows the second separating member to self-attach to the first separating member without external fixation mechanisms. The structure itself provides the connection, reducing manufacturing complexity and eliminating the need for additional fastening steps.
Data Source
AI summary
The present application discloses an electrode assembly and a related battery cell, battery, apparatus and manufacturing method therefor. The electrode assembly may include: a first electrode sheet and a second electrode sheet having opposite polarities; and a separator configured to separate the first electrode sheet and the second electrode sheet, the separator including at least two layers, where the first electrode sheet, the second electrode sheet and the separator may be wound to form the electrode assembly.