Wound Electrode Assembly With Graded Active Material at Bends
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Solution Overview
Problem
The improper distribution of active substance in electrode plates of lithium-ion batteries leads to inefficiencies, resulting in excess active substance in the inner parts and insufficiency in the outer parts, which is less cost-effective.
Innovation Solution
The negative and positive electrode plates are designed with specific bending portions where the active substance capacity per unit area is greater in the outer parts than in the inner parts, ensuring a more even distribution and reducing the likelihood of lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active substance is uniformly distributed in electrode plates, then manufacturing is simple, but there is excess active substance in inner parts and insufficiency in outer parts leading to improper distribution
Solution Approach 1:
The patent applies local quality by creating non-uniform active substance distribution that matches the local requirements of different electrode plate regions. Specifically, the outer parts of bending portions have higher active substance capacity per unit area than inner parts, compensating for the expansion-compression effects during winding and ensuring optimal performance in each local zone rather than uniform distribution throughout.
2Reliability
If active substance capacity per unit area is increased in outer parts of bending portions, then lithium precipitation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-distributing active substance in a non-uniform pattern during electrode plate manufacturing, before the winding process occurs. The outer parts of bending portions are designed with higher active substance capacity per unit area in advance, so that when the electrode plates are wound and bending portions form, the distribution automatically compensates for expansion-compression effects and prevents lithium precipitation without requiring complex post-processing.
Data Source
AI summary
Embodiments of this application provide an electrode assembly, a manufacturing method and manufacturing system of same, a battery cell, and a battery. The electrode assembly includes a negative electrode plate and a positive electrode plate, where the negative electrode plate and the positive electrode plate are wound in a winding direction to form a winding structure, and the winding structure includes a bending zone. The negative electrode plate and the positive electrode plate each include a plurality of bending portions located in the bending zone.