Jelly-roll Electrode Assembly Tab Protection
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Solution Overview
Problem
Conventional jelly-roll type electrode assemblies in secondary batteries are prone to electrical short-circuiting due to separator damage, especially at the points where electrode tabs are welded, and this issue is exacerbated by manufacturing defects like burrs, leading to increased manufacturing complexity and costs.
Innovation Solution
The electrode assembly incorporates additional protective separators positioned on the sides of the electrode strips attached with tabs, which are extended and bent to create a multi-layer structure, preventing short-circuiting by increasing insulation between the electrode strips and protecting against defects and heat-induced damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is used between electrode strips, then electrical insulation is provided, but the separator is prone to breaking at welded portions causing short-circuiting
Solution Approach 1:
The patent applies beforehand cushioning by extending the separator beyond the electrode strips to create overlapping regions. This extended separator portion acts as a protective cushion that prevents direct contact between electrode tabs of opposite polarity, thereby preventing short-circuiting before it can occur. The separator is positioned to overlap with electrode tabs in a direction perpendicular to the rolling direction, creating a buffer zone that absorbs potential damage.
2Ease of operation
If electrode tabs are welded to electrode strips, then electrical charge movement is enabled, but heating occurs causing separator breaking
Solution Approach 1:
The patent introduces an intermediary solution by extending the separator to overlap with the heated electrode tab regions. This extended separator acts as a thermal and electrical intermediary barrier between adjacent electrode tabs of opposite polarity. The separator material provides both electrical insulation and thermal protection, preventing heat-induced short-circuiting while allowing the electrode tabs to function normally for charge movement.
3Reliability
If manufacturing precision is maintained to avoid burrs, then separator damage is prevented, but manufacturing complexity and costs increase
Solution Approach 1:
The patent applies beforehand cushioning by extending the separator beyond the electrode strips to create overlapping regions. This extended separator portion acts as a protective cushion that prevents direct contact between electrode tabs of opposite polarity, thereby preventing short-circuiting before it can occur. The separator is positioned to overlap with electrode tabs in a direction perpendicular to the rolling direction, creating a buffer zone that absorbs potential damage.
4Reliability
If protective measures are added to prevent short-circuiting, then battery safety is improved, but battery volume and complexity increase
Solution Approach 1:
The patent applies universality by making the separator serve multiple functions: its primary function of electrical insulation between electrode strips, and a secondary protective function through the extended portions that overlap with electrode tabs. This multi-functional design provides short-circuit prevention without adding separate protective components, thereby avoiding increased battery volume and complexity while maintaining improved safety.
Data Source
AI summary
An electrode assembly including a first electrode strip having a first electrode collector coated with at least a first electrode active material, an exposed portion of the first electrode collector attached with a first electrode tab; a second electrode strip having a second electrode collector coated with at least a second electrode active material and is rolled together with the first electrode strip, an exposed portion of the second electrode collector is attached with a second electrode tab; and at least one inter-electrode strip separator is positioned between the first and second electrode strips, wherein at least one sheet of protective separator, which is extended from the inter-electrode strip separator, is further positioned on a side of the first electrode strip attached with the first electrode tab.