Battery Current Collector Edge Coating for Stable Welding
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Solution Overview
Problem
Existing lithium-ion cells face challenges in welding the thin current collector edges due to mechanical sensitivity, which can lead to deformation, melting, and potential short circuits.
Innovation Solution
The electrode-separator assembly features an anode and cathode current collector with a strip-shaped edge region not loaded with electrode material, which is partially or completely coated with an electrically non-conductive support material, ensuring mechanical stability and preventing unintended deformation during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the current collector edges are made thin to reduce weight and increase energy density, then the energy density improves, but the mechanical stability deteriorates causing deformation and melting during welding
Solution Approach 1:
The current collector is segmented into a thin main region (for high energy density) and a thicker edge region (for mechanical stability and welding). This segmentation allows different parts of the same component to have different thicknesses, optimizing both energy density and weldability without compromising overall structural integrity
Solution Approach 2:
The current collector exhibits local quality variation through its non-uniform thickness distribution. The main region maintains thinness for high energy density, while the edge region is locally thickened to provide mechanical support during welding operations. This local quality adjustment resolves the contradiction between thinness and mechanical stability
2Quantity of substance
If the current collector edges are made thin to improve energy density, then the energy density improves, but the manufacturing precision deteriorates due to deformation and melting during welding
Solution Approach 1:
The current collector is divided into a thin main region and a thicker edge region. This segmentation ensures that the welding process acts only on the thicker edge region, which has sufficient mechanical stability to maintain manufacturing precision, while the thin main region preserves high energy density
Solution Approach 2:
By creating a local thickness variation with a thicker edge region, the manufacturing precision is improved in the welding zone without affecting the overall thinness and energy density of the current collector. The local quality change confines the welding process to a stable region
Data Source
AI summary
An electrochemical energy storage element includes an electrode-separator assembly that includes an anode, a cathode, and at least one separator or solid electrolyte. The anode and cathode each include an anode current collector in the form of an electrically conductive substrate having a top side, a bottom side, and an edge. The anode current collector and/or the cathode current collector includes a main region loaded on both sides with a layer of electrode material and an edge region not loaded with the electrode material that extends in a strip-shaped manner along the edge of the current collector. The electrode-separator assembly has a side from which a respective edge protrudes. A respective edge region extending along the respective edge is partially or completely coated with an electrically non-conductive layer of a support material.