Jelly-Roll Electrode Tab Structure to Prevent Coating Detachment
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Solution Overview
Problem
Existing electrode assemblies in battery cells face issues such as active material coating layer detachment during tab slitting and separator burning during welding, due to the high bending strength of long tabs wound into a ring shape.
Innovation Solution
The electrode assembly incorporates a tab portion with a continuous region near the active material layer and a spacing region with multiple tabs spaced apart, formed by die-cutting. This design ensures a specified spacing between the tab and the current collector, preventing active material loss and improving battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long tabs are wound into a ring shape to form the electrode assembly, then the electrode assembly can be formed with continuous tabs for electrical connection, but the high bending strength of the long tabs causes active material coating layer detachment during tab slitting and separator burning during welding
Solution Approach 1:
The continuous tab portion is segmented into multiple discrete tabs by die-cutting, transforming the long continuous tab into several shorter tabs. This segmentation reduces the bending strength and flexibility of the tab material, preventing active material coating layer detachment during slitting and separator burning during welding, while still maintaining electrical connection functionality
Solution Approach 2:
The tab portion is designed with different structural characteristics in different regions: the continuous region maintains integrity for electrical connection, while the spacing region is die-cut into discrete tabs with reduced bending strength. This local differentiation allows the tab structure to simultaneously achieve reliable electrical connection and prevent harmful effects during processing
2Object-affected harmful factors
If the tab portion is die-cut into multiple spaced tabs, then the bending strength is reduced to prevent active material detachment, but the tab structure becomes more complex
Solution Approach 1:
The tab portion is divided into two functional regions: a continuous region that maintains structural integrity and electrical connection, and a spacing region that is die-cut into discrete tabs. This segmentation approach simplifies the overall structure compared to completely discrete tabs while still achieving the goal of reducing bending strength to prevent active material detachment
Solution Approach 2:
The continuous region of the tab portion serves multiple functions: it provides structural support, maintains electrical connection integrity, and facilitates handling during assembly. This multi-functionality reduces the need for additional supporting structures, thereby reducing overall device complexity while still preventing active material detachment
Data Source
AI summary
An electrode assembly includes a first electrode plate and a second electrode plate that are of opposite polarities, and includes a separator disposed between the first electrode plate and the second electrode plate. The first electrode plate, the separator, and the second electrode plate are wound along a winding direction to form a jelly-roll structure. At least one of the first electrode plate or the second electrode plate includes: a current collector; an active material layer, disposed at least on a surface of the current collector on a side near the separator; and a tab portion, connected to one lateral edge of the current collector, where the lateral edge extends along the winding direction.