Electrode Assembly Winding Thickness Reduction
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Solution Overview
Problem
The irregular thickness of electrode assemblies in lithium ion secondary batteries, caused by conductive tabs and insulation tape, leads to difficulties in insertion into cans or pouches, resulting in deformation and potential degradation of battery capacity.
Innovation Solution
The electrode assembly design features active materials coated on the outer surfaces of collectors near the conductive tabs, with specific spacing to minimize overall winding thickness, allowing for easier insertion and reducing protrusion, thereby improving workability and maintaining battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive tabs and insulation tape are added to the electrode assembly, then electrical connection and insulation are improved, but the overall thickness increases and insertion difficulty increases
Solution Approach 1:
The patent extracts the harmful protrusion effect by removing active materials from the regions where conductive tabs and insulation tape are located. This prevents these components from creating excessive thickness while maintaining their essential electrical functions.
Solution Approach 2:
The patent applies local quality by creating different active material thicknesses in different regions of the electrode assembly. Specifically, active materials are omitted from regions corresponding to conductive tabs and insulation tape, while maintaining normal thickness in other regions, thus optimizing both electrical performance and insertion characteristics.
2Ease of operation
If the electrode assembly is pressed or squeezed to achieve desired insertion, then insertion difficulty is reduced, but active materials are compressed and battery capacity degrades
Solution Approach 1:
The patent performs preliminary action by pre-configuring the active material distribution to account for the conductive tabs and insulation tape positions before assembly. This prevents the need for post-assembly compression that would damage the active materials and reduce battery capacity.
3Reliability
If active materials are coated on regions overlapping conductive tabs, then battery capacity is maximized, but winding thickness increases and deformation occurs
Solution Approach 1:
The patent applies local quality by creating different active material thicknesses in different regions of the electrode assembly. Specifically, active materials are omitted from regions corresponding to conductive tabs and insulation tape, while maintaining normal thickness in other regions, thus optimizing both electrical performance and insertion characteristics.
Data Source
AI summary
An electrode assembly and a lithium ion secondary battery using the electrode assembly having reduced winding thickness. Active materials are coated on a first region of a negative electrode collector to which a negative electrode conductive tab is welded, and on an adjacent region overlapping the first region. Active materials are also coated on a first region of a positive electrode collector, to which a positive electrode conductive tab is welded, and an adjacent region overlapping the first region. Parts of the electrode assembly corresponding to the conductive tabs do not protrude from the electrode assembly, allowing for easy insertion of the electrode assembly into a can or pouch.