Wound Battery Cell Tab Layout for Low Resistance and High Energy Density
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Solution Overview
Problem
Battery cells with embedded single-tab structures face high internal resistance and temperature rise issues during high-rate charging, while external tabs with insulation layers reduce energy density due to space requirements.
Innovation Solution
A battery cell design incorporating both embedded and external tabs, where the embedded tab structure avoids space for welding and the external tab structure reduces internal resistance, with optimized tab placement and overlap to enhance current channels and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an embedded single-tab structure is used on the anode electrode plate, then the energy density is improved by eliminating the need for uncoated regions, but the internal resistance becomes too large and the charging temperature rises excessively
Solution Approach 1:
The anode electrode plate is divided into multiple tabs (first tab and second tab) instead of using a single tab structure. This segmentation distributes the current flow paths, reducing current density at each tab location and thereby reducing internal resistance and heat generation during high-rate charging while maintaining the embedded tab configuration that preserves active substance coverage.
2Reliability
If external tabs with insulation coating are used on the cathode electrode plate, then the internal resistance is reduced and temperature rise is controlled, but the insulation layer requires additional space resulting in energy density loss
Solution Approach 1:
The insulation coating is removed from the cathode electrode plate edge and tab regions. The patent uses an embedded tab structure where the cathode tab is integrated into the active substance layer without requiring separate insulation layers, thereby eliminating the space occupied by insulation materials and improving energy density while maintaining acceptable electrical performance.
Solution Approach 2:
The cathode tab is embedded within the active substance layer rather than extending externally with insulation. The tab structure is nested into the electrode plate thickness, with the active substance layer covering the current collector at the tab location, creating a compact integrated structure that eliminates the need for external insulation space.
3Reliability
If multiple first tabs are provided on the anode electrode plate, then the quantity of current channels increases and internal resistance is reduced, but the complexity of tab arrangement and welding increases
Solution Approach 1:
The patent provides multiple first tabs at specific locations on the anode electrode plate rather than uniformly distributing tabs. The tabs are positioned at optimized locations (e.g., at thirds or quarters of the electrode plate length) to create adequate current channels while maintaining manageable welding complexity. Each tab location is carefully selected to balance current distribution with manufacturing feasibility.
Data Source
AI summary
A battery cell is formed by winding a first electrode plate, a separator, and a second electrode plate, the first electrode plate includes a first current collector, a first active substance layer disposed on a surface of the first current collector, and at least one first tab; the first active substance layer is provided with a first groove, and the first tab is disposed in the first groove and electrically connected to the first current collector; the second electrode plate includes a second current collector, a second active substance layer disposed on a surface of the second current collector, and at least one second tab; and the second tab and the second current collector are integrally formed.