Flat-Wound Electrode Body Positioning Method
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Solution Overview
Problem
The existing methods for producing flat-wound electrode bodies fail to consistently position the positive electrode end portion correctly, leading to uneven inter-electrode distances and potential metal precipitation due to the positive electrode end portion floating up during the flattening process, which affects the performance and reliability of batteries.
Innovation Solution
A method that involves winding the positive and negative electrode plates with separators into a cylindrical shape and then pressing them to form a flat-wound electrode body, ensuring the positive electrode end portion is positioned in the flat portion to prevent floating and maintain even electrode distances, with the circumferential position of the separator end portion serving as a reference for accurate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cylindrical-wound electrode body is pressed without controlling the circumferential position of the positive electrode end portion, then the pressing process is simple and fast, but the positive electrode end portion floats up causing uneven inter-electrode distances
Solution Approach 1:
The patent applies preliminary action by establishing a predetermined circumferential positional relationship between the positive electrode end portion and the first separator end portion during the winding process. This positioning is determined before pressing, allowing the pressing operation to proceed efficiently without real-time position adjustment while ensuring the positive electrode end portion ends up in the flat portion after flattening.
Solution Approach 2:
The patent replaces complex mechanical positioning systems with a reference-based method. Instead of using sophisticated mechanical devices to track and position the positive electrode end portion during pressing, the invention uses the easily observable first separator end portion as a reference marker, substituting complex mechanical control with a simpler reference-point approach.
2Ease of manufacture
If the positive electrode end portion is positioned in the R part of the flat-wound electrode body, then the winding process is simple, but the positive electrode end portion floats up causing unevenness in inter-electrode distance
Solution Approach 1:
The patent applies local quality by specifying that the positive electrode end portion must be positioned in a particular location (the flat portion) of the final electrode body, rather than uniformly distributing all end portions. This localized positioning requirement ensures that the critical positive electrode end portion is placed in the optimal location for preventing floating, while maintaining overall manufacturing simplicity.
3Productivity
If the circumferential position of the positive electrode end portion is not controlled, then the manufacturing process is simple and fast, but metal precipitation occurs due to uneven inter-electrode distances
Solution Approach 1:
The patent prevents metal precipitation by performing preliminary positioning of the positive electrode end portion relative to the first separator end portion during winding. This advance positioning ensures that after pressing, the positive electrode end portion will be in the flat portion with uniform inter-electrode distance, preventing the harmful effect of metal precipitation without slowing down the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures consistent positioning of the positive electrode end portion in the flat-wound electrode body, preventing metal precipitation and maintaining uniform inter-electrode distances, thereby enhancing the performance and reliability of batteries and battery modules.
Implementation Method 1
pressing the cylindrical-wound electrode body to be flattened to form the flat-wound electrode body
Data Source
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AI summary
A producing method of a flat-wound electrode body (1), which is formed by winding a strip-shaped positive electrode plate (10) and a strip-shaped negative electrode plate (20) via a pair of separators (30,40) into a flat shape, includes winding (S11) of forming a cylindrical-wound electrode body (1Z) by winding the positive electrode plate (10) and the negative electrode plate (20) interposed with the pair of separators (30,40) into a cylindrical shape, and pressing (S12) of forming the flat-wound electrode body (1) by pressing and flattening the cylindrical-wound electrode body (1Z). The pressing (S12) is to perform pressing to position a positive electrode end portion (10e) at a winding end of the positive electrode plate (10) in a flat portion (2) of the flat-wound electrode body (1).