Zigzag Folded Electrode Tracks for Lithium-Ion Battery Safety
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Solution Overview
Problem
Existing electrode arrangements in lithium-ion batteries face issues with dendrite formation and material expansion, leading to high internal resistance and potential short circuits, which reduce the battery's service life and safety.
Innovation Solution
The electrode arrangement features a layer structure with conductive tracks in zigzag folds, separated by an insulating track, where the conductive tracks are coated with active material only on one side to prevent detachment and have gaps at fold edges, and the insulating track is made of ceramic material for enhanced mechanical strength and temperature resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode arrangements are used in lithium-ion batteries, then the battery can store and release electrical energy, but dendrite formation and material expansion occur leading to high internal resistance and potential short circuits
Solution Approach 1:
The patent applies local quality by coating the conductive tracks with active material only on one side rather than uniformly on both sides. This selective coating prevents material detachment at fold edges while maintaining electrochemical functionality in the required areas, thereby reducing dendrite formation and material expansion that lead to short circuits.
Solution Approach 2:
The patent segments the conductive tracks by introducing gaps at the fold edges where active material is not applied. This segmentation isolates the potential harmful areas (fold edges) from the active material, preventing dendrite formation and material expansion at these critical locations while preserving battery functionality.
2Strength
If the separator is made of conventional insulating material, then it provides basic electrical insulation, but it lacks sufficient mechanical strength and temperature resistance
Solution Approach 1:
The patent uses ceramic material for the insulating track instead of conventional organic insulators. Ceramic materials provide superior mechanical strength and temperature resistance, preventing deformation and failure under thermal and mechanical stress, thereby enhancing overall battery safety and reliability.
3Quantity of substance
If the conductive tracks are coated with active material on both sides, then the electrochemical capacity is maximized, but material detachment occurs at fold edges leading to performance degradation
Solution Approach 1:
The patent implements local quality by applying active material coating only on one side of the conductive tracks. This selective coating strategy maintains sufficient electrochemical capacity while eliminating the problem of material detachment at fold edges, as the uncoated edges remain flexible and adherent during folding operations.
Data Source
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AI summary
The invention relates to an electrode assembly (110), which comprises a layer structure. Said layer structure has at least one first electrode (112), at least one second electrode (130), and at least one separator (116) inserted between the first electrode (112) and the second electrode (130). The first electrode (112) has at least one first conductive track (114), wherein the first conductive track (114) is folded in a first zig-zag fold, wherein a plurality of first layers (120, 122) lying one over the other is formed by the first zig-zag fold and wherein first folded edges (134, 136) of the first zig-zag fold lying opposite each other define a first folding direction (138) of the first zig-zag fold. Furthermore, the second electrode (130) has at least one second conductive track (132), wherein the second conductive track (132) is folded in a second zig-zag fold, wherein a plurality of second layers (128, 140) lying one over the other is formed by the second zig-zag fold and wherein second folded edges (142) of the second zig-zag fold lying opposite each other define a second folding direction (144) of the second zig-zag fold. According to the invention, the first layers (120, 122) and the second layers (142) are arranged parallel to each other, wherein the first folding direction (138) and the second folding direction (144) assume an angle of at least 60° and at most 120° to each other, and wherein the separator (116) is present in the form of at least one insulating track (118), wherein each two adjacent first layers (120, 122) lie one over the other in such a way that said first layers form a double layer (124, 126), and a second layer (128, 140) is inserted between two double layers (124, 126). The invention further relates to a method for producing such an electrode assembly (110), and to an electrochemical cell, comprising at least one such electrode assembly (110), at least one electrolyte, at least one first conductor for the first electrode (112), and at least one second conductor for the second electrode (130).