Battery Electrode Assembly Winding and Flattening Spacer Extraction
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Solution Overview
Problem
Existing battery production methods often result in creasing and strain during the pressing of electrode assemblies, leading to battery shape deformation and reduced quality, such as volumetric energy density and cycle characteristics, due to concentrated stress.
Innovation Solution
A method involving the insertion of a rod-shaped spacer parallel to the axial direction during winding, which is then pulled out before flattening, to disperse stress and prevent creasing and strain by positioning the spacer orthogonally to the pressing direction and symmetrically around the shaft center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If pressing is carried out with the spacer inserted in the electrode assembly, then the space formation in the electrode assembly is maintained, but the spacer prevents effective prevention of creasing and strain production during pressing
Solution Approach 1:
The spacer is extracted (pulled out) from the wound electrode assembly between the winding step and the flattening step. This extraction allows the electrode assembly to be pressed without the spacer present, enabling effective prevention of creasing and strain while maintaining the space formation achieved during winding.
Solution Approach 2:
The spacer is inserted during the winding step to preliminarily form spaces in the electrode assembly. This preliminary action creates the desired space structure before the spacer is removed, allowing the spaces to be established before pressing occurs.
2Manufacturing precision
If no spacer is used during pressing, then creasing and strain can be prevented, but space formation in the electrode assembly cannot be effectively maintained
Solution Approach 1:
The spacer performs the preliminary action of forming spaces in the electrode assembly during the winding step. After this space formation is accomplished, the spacer is removed before pressing, allowing both space formation and creasing prevention to be achieved through sequential operations.
Solution Approach 2:
The spacer is taken out from the electrode assembly after serving its space-forming function during winding. This extraction timing is critical - it remains during winding to form spaces, then is removed before pressing to allow effective flattening without creasing.
3Shape
If the electrode assembly is pressed without proper stress distribution, then flattening is achieved, but concentrated stress causes creasing and strain in the electrode assembly
Solution Approach 1:
The rod-shaped spacer acts as an intermediary element during winding, creating spaces that serve as stress distribution zones. When the spacer is removed and pressing is applied, these pre-formed spaces help distribute the stress more evenly throughout the electrode assembly, preventing concentrated stress points that would cause creasing.
Data Source
AI summary
A battery production method according to the invention includes a winding step of winding an electrode assembly around a winding core and a flattening step of pressing the electrode assembly wound in the winding step, in a direction orthogonal to an axial direction thereof to form a flattened shape in which the wound electrode assembly is flattened in a direction that is orthogonal to the pressing direction and the axial direction, wherein a rod-shaped spacer is inserted, in parallel to the axial direction, into the electrode assembly wound during the course of winding the electrode assembly around the winding core in the winding step, and wherein the spacer is pulled out between the winding step and the flattening step.