Integral Battery Tab Design for Jelly Roll Impedance
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Solution Overview
Problem
Existing battery designs, particularly jelly roll batteries, face challenges with high impedance, poor thermal properties, and complex manufacturing processes due to the need for precise alignment and welding of current collector tabs, which limits the number of tabs and affects overall cell performance.
Innovation Solution
The design integrates electrode tabs by extending bare electrode foil beyond the electrode coating and cutting out tab profiles after winding, eliminating the need for welding and allowing for multiple tabs per winding, which reduces impedance and improves thermal transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple conducting tabs are inserted by welding at carefully selected intervals within the structure before rolling, then electrical connections to battery terminals are provided, but the manufacturing process becomes complex and requires precise alignment and winding
Solution Approach 1:
The tabs are formed as integral extensions of the electrode sheets during the winding process itself, rather than being added separately before rolling. This preliminary integration eliminates the need for post-assembly welding operations and precise alignment procedures, while still providing reliable electrical connections.
Solution Approach 2:
The tab structure is merged with the electrode sheet as a single integral component. The tabs are formed from the same material and are created during the winding process, combining the electrode and tab functions into one unified structure that eliminates separate welding steps.
2Manufacturing precision
If tabs are welded prior to rolling, then electrical connections are established, but the jelly roll must be precisely wound to create aligned tabs in the final rolled cell
Solution Approach 1:
Instead of welding tabs to flat electrode sheets before rolling (which requires precise winding to maintain alignment), the tabs are formed by cutting the wound jelly roll itself. This inverts the traditional sequence, making the winding process simpler while achieving precise tab alignment through the cutting operation after rolling.
Solution Approach 2:
The electrode sheets are wound into the jelly roll structure first, establishing the compact cylindrical form. Only after this preliminary winding is complete are the tabs created by cutting, which automatically produces aligned tabs without requiring precise control during the winding process itself.
3Productivity
If the number of tabs per winding is increased, then impedance is reduced and thermal transfer is improved, but the manufacturing complexity increases due to more welding operations
Solution Approach 1:
The winding process itself creates the tab structures through cutting operations performed on the already-wound jelly roll. The system serves itself by using the wound structure as the basis for tab formation, eliminating the need for separate welding operations for each tab while still allowing multiple tabs per winding to improve electrical and thermal performance.
Data Source
AI summary
One aspect of the present disclosure relates to a wound electromechanical storage device assembly including a negative electrode sheet, a plurality of negative electrode tabs which are integral to and extend from the negative electrode sheet, a positive electrode sheet, a plurality of positive electrode tabs which are integral to and extend from the positive electrode sheet, and a separator sheet disposed between the negative and positive electrode sheets, wherein the negative electrode sheet, positive electrode sheet, and separator sheet are wound around a common axis to form a plurality of windings, and wherein each winding includes one negative electrode tab and one positive electrode tab.