Folded Lithium-Metal Electrode Assembly for Deformation Control
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Solution Overview
Problem
Conventional electrode assemblies face issues with deformation due to stress accumulation during charge and discharge, leading to performance degradation and safety risks, especially when using lithium metal as a negative electrode, and have low productivity due to complex manufacturing processes.
Innovation Solution
A novel electrode assembly structure with a negative electrode interposed between two separating films, divided into stack and folding portions, and wrapped by folding portions to minimize lithium metal processing, allowing for improved process efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If jelly-roll electrode assembly is made by winding long sheet of positive electrodes and negative electrodes in dense state, then battery capacity is improved, but stress accumulation during charge and discharge causes deformation and performance degradation
Solution Approach 1:
The electrode assembly is divided into multiple electrode units, each comprising positive electrodes, negative electrodes, and separating films stacked in sequence. This segmentation allows each unit to independently accommodate expansion and contraction during charge-discharge cycles, preventing stress accumulation and deformation while maintaining high battery capacity through the aggregation of multiple units.
2Quantity of substance
If jelly-roll electrode assembly is wound in dense state, then battery capacity is improved, but manufacturing complexity increases due to difficulty in maintaining constant spacing
Solution Approach 1:
The electrode assembly is divided into multiple electrode units, each comprising positive electrodes, negative electrodes, and separating films stacked in sequence. This segmentation allows each unit to independently accommodate expansion and contraction during charge-discharge cycles, preventing stress accumulation and deformation while maintaining high battery capacity through the aggregation of multiple units.
3Stability of the object's composition
If stackable electrode assembly requires sequential stacking of multiple positive electrodes and negative electrode units, then electrode deformation is reduced, but productivity decreases due to time-consuming stacking process
Solution Approach 1:
The electrode units are pre-assembled with separating films positioned between positive and negative electrodes before final stacking. This preliminary arrangement ensures proper spacing and alignment are established in advance, reducing the time and complexity of the final stacking process while maintaining electrode stability and preventing deformation.
4Quantity of substance
If lithium metal is used as negative electrode material, then battery capacity is improved, but processing difficulty increases due to high ductility and viscosity making cutting difficult
Solution Approach 1:
The lithium metal negative electrode is configured as a thin film structure with sufficient flexibility to be wrapped around the electrode units. This thin film configuration reduces processing difficulty compared to bulk lithium metal, as thin films can be more easily handled, positioned, and integrated into the electrode assembly without requiring extensive cutting operations.
Data Source
AI summary
An electrode assembly, including: a negative electrode structure; and a plurality of positive electrodes, wherein the negative electrode structure includes first and second separating films, and a lithium metal layer interposed between the first and second separating films, wherein the negative electrode structure is divided into a plurality of stack portions, a plurality of folding portions, and first and second wrapping portions, wherein the stack portion and the folding portion are located alternately between the first and second wrapping portions located at an end of the negative electrode structure, respectively, and the first and second wrapping portions abut the stack portion, wherein the plurality of stack portions are sequentially positioned side by side in a thickness direction by the folding portion, and at least one positive electrode is positioned between the stack portions adjacent each other in the thickness direction, and wherein the second wrapping portion is positioned to abut the first wrapping portion, and an outer surface of the electrode assembly in the thickness direction and in a longitudinal direction is surrounded by the second wrapping portion, or by the second wrapping portion and at least one of the first wrapping portion and an outermost stack portion.