Segmented Electrode Assembly for Battery Safety and Productivity
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Solution Overview
Problem
Conventional electrode assemblies, such as jelly-roll and stack/folding types, face issues with stress accumulation, deformation, internal short circuits, and low productivity due to complex preparation processes, leading to safety concerns and reduced battery performance.
Innovation Solution
A novel electrode assembly structure where a plurality of first unit electrodes and a second electrode sheet are wound with a separator sheet in between, ensuring opposite polarities and eliminating the need for welding second electrode tabs to a lead, thereby preventing short circuits and simplifying the preparation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If long-sheet type cathodes and anodes are densely wound in a jelly-roll type structure, then the battery can be manufactured with a compact form, but stress accumulation during charge and discharge causes electrode assembly deformation and internal short circuits
Solution Approach 1:
The electrode assembly is divided into multiple unit electrodes (first unit electrodes and second unit electrodes) that are separately wound around a core, rather than using a single long-sheet structure. This segmentation reduces stress accumulation and prevents deformation while maintaining compact form factor.
Solution Approach 2:
A core structure is introduced as an intermediary element around which the unit electrodes are wound. This core provides structural support and maintains the integrity of the electrode assembly during charge and discharge cycles, preventing the deformation that occurs in traditional jelly-roll structures.
2Manufacturing precision
If long-sheet type cathodes and anodes are wound to maintain uniform gap, then electrode performance is improved, but the winding process becomes difficult and productivity is lowered
Solution Approach 1:
The electrode assembly is segmented into multiple smaller unit electrodes that are wound separately around a core. This segmentation makes the winding process easier to control and maintain uniform gaps, while the modular approach enables faster production compared to winding a single long-sheet structure.
3Ease of manufacture
If unit cathodes and anodes are sequentially stacked in a stack type structure, then electrode arrangement is simplified, but additional transfer processes are required and productivity is lowered
Solution Approach 1:
The winding process merges multiple functions (arrangement, spacing, and assembly) into a single operation. Unit electrodes are wound around a core in a continuous process that simultaneously achieves proper electrode arrangement and maintains uniform gaps, eliminating the need for separate transfer and positioning steps required in stack type structures.
4Reliability
If a stack/folding type electrode assembly is used, then some problems of jelly-roll and stack types are solved, but electrode tabs may contact the battery body under external impact causing short circuits
Solution Approach 1:
The electrode assembly is divided into multiple unit electrodes wound around a core, creating a more compact and stable structure. This segmentation reduces the protrusion of electrode tabs and minimizes the risk of contact with the battery body under external impact, while maintaining the stability improvements of the stack/folding type.
Data Source
AI summary
Disclosed herein is an electrode assembly of a cathode/separator/anode structure, wherein a plurality of first unit electrodes and a second electrode sheet are wound so that the first unit electrodes are opposite to the second electrode sheet via a separator sheet, and a first electrode and a second electrode have opposite polarities.