Electrode-Separator Composite With Reinforced Edges for Reliable Welding
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Solution Overview
Problem
The existing electrode separator networks for lithium-ion cells face challenges in welding the thin power collectors, which can lead to mechanical sensitivity and potential short circuits due to the thin edge areas, making it difficult to achieve reliable electrical contact and high energy density.
Innovation Solution
The electrode separator network features a composite structure with anode and cathode current collectors having a main area loaded with electrode material and a marginal area coated with a support material, which provides mechanical stability and prevents deformation during welding, ensuring reliable electrical contact and reduced internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thin current collectors are used to increase energy density, then energy density is improved, but mechanical stability and welding reliability deteriorate
Solution Approach 1:
The current collector is segmented into two functional zones: a thin main area (5-20 μm) for high energy density and a thicker edge area (15-30 μm) for mechanical stability and welding reliability. This segmentation allows each zone to optimize its specific function without compromising the other.
Solution Approach 2:
Different thicknesses are applied locally to different regions of the current collector. The central region maintains thinness for energy density, while the edge region is thicker to provide mechanical support and welding stability. This local quality variation resolves the contradiction between thinness and reliability.
2Quantity of substance
If thin current collectors are used to increase energy density, then energy density is improved, but mechanical stability deteriorates
Solution Approach 1:
The current collector structure is segmented into a thin main body for energy storage and a thicker edge border for mechanical strength. This segmentation enables the thin central region to maximize energy density while the thicker edge region provides the necessary mechanical stability.
Solution Approach 2:
The current collector exhibits local quality variation with different thicknesses in different regions. The thin central area (5-20 μm) optimizes energy density, while the thicker edge area (15-30 μm) provides mechanical stability and structural support.
3Quantity of substance
If edge areas are thinned to increase energy density, then energy density is improved, but electrical contact reliability deteriorates
Solution Approach 1:
The current collector is segmented into a thin active area for energy density and a thicker edge area for electrical contact. This segmentation ensures that the thinning process does not compromise the reliability of electrical contacts at the edges.
Solution Approach 2:
Different thicknesses are applied locally: the main active area is thin (5-20 μm) for high energy density, while the edge area maintaining electrical contact functions is thicker (15-30 μm) for reliable connectivity.
Data Source
Figure 1A~1D
Figure 2~3
Figure 4
AI summary
An electrode-separator assembly (104) for an electrochemical energy storage element (100) comprises at least one anode (105) and at least one cathode (108) as electrodes, as well as at least one separator (116) or at least one solid electrolyte with the sequence anode (105) / separator (116) or solid electrolyte / cathode (108). The anode (105) comprises an anode current collector (106), and the cathode (108) comprises a cathode current collector (109). The current collectors (106, 109) are thin, electrically conductive substrates having a top, a bottom, and a rim (106a).The anode current collector (106) and/or the cathode current collector comprise a main region (106c, 109c) loaded on both sides with a layer of negative electrode material (107) or positive electrode material (110), and a marginal region (106b, 109b) extending in a strip along the edge (106a, 109a) and not loaded with the respective electrode material. The assembly (104) has a side (104a or 104b) from which the edge (106a) of the anode current collector (106) or the edge (109a) of the cathode current collector (108) protrudes. The edge region (106b, 109b) extending along the edge (106a or 109a) emerging from the side (104a or 104b) is partially or completely coated with an electrically non-conductive layer of a support material (133).The electrode, whose current collector encompasses the edge (106a or 109a) emerging from the side (104a or 104b), has a first mean thickness D1 in the main region of its current collector and a maximum thickness D2 in the edge region coated with the layer of support material (133). D2 is less than D1.