Wound Electrode Tab Layout for Battery Resistance and Impregnation
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Solution Overview
Problem
Existing tab-less secondary batteries face issues with resistance properties, cycle life properties, and manufacturing process efficiency due to variations in internal structure design.
Innovation Solution
An electrode assembly with a coated region and an uncoated region, featuring protrusions extending perpendicular to the winding direction, where the widths of the protrusions vary, and a margin portion is included to improve electrolyte impregnation and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire surface of the current collector plate is used as a conductor to transfer electrons, then internal resistance can be reduced and heat can be dispersed, but differences arise in resistance properties, cycle life properties and manufacturing process efficiency
Solution Approach 1:
The electrode current collector is designed with different regions having different properties: a coated region with active material for electrochemical reactions and an uncoated region serving as a tab region for electrical connection. This local differentiation optimizes both electrical conductivity and structural simplicity, resolving the contradiction between improving electrical properties and reducing device complexity.
Solution Approach 2:
The electrode assembly is segmented into multiple functional zones along the winding direction, including first and second tab regions with different protrusion widths. This segmentation allows optimized electrical contact at different positions while maintaining a relatively simple overall structure, addressing the contradiction between reliability and device complexity.
2Reliability
If the uncoated region includes protrusions with varying widths in different tab regions, then electrolyte impregnation properties are improved, but manufacturing precision requirements increase
Solution Approach 1:
Different tab regions (first tab region closer to winding start, second tab region farther away) are designed with different protrusion width characteristics. The first tab region has wider protrusions for better electrolyte impregnation at the winding start, while the second tab region has narrower protrusions. This local quality differentiation improves overall electrolyte distribution while providing clear manufacturing guidelines for each region.
Solution Approach 2:
The protrusions in the first tab region are designed with greater width (excessive action) to ensure sufficient electrolyte impregnation at the critical winding start area, while the second tab region uses standard width protrusions. This partial application of enhanced features improves electrolyte distribution without requiring excessive precision across the entire structure.
Data Source
AI summary
An electrode assembly according to embodiments of the present disclosure includes a separator and an electrode wound with the separator therebetween. The electrode includes an electrode current collector including a coated region and an uncoated region, and an active material layer formed on the coated region of the electrode current collector. The uncoated region includes a tab region including protrusions that extend in a direction perpendicular to the winding direction of the electrode and parallel to the coated region. The tab region includes protrusions having different widths.