Wound Electrode Assembly With Local Active Material in Bending Zones
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Solution Overview
Problem
Existing technologies face challenges in efficiently addressing the issue of improper distribution of active substance in electrode plates, which is less cost-effective.
Innovation Solution
The electrode assembly is designed with a winding structure that includes a negative electrode plate and a positive electrode plate, where the bending portions are configured to have varying active substance capacities per unit area, ensuring proper distribution and reducing lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If active substance is uniformly distributed in electrode plates, then manufacturing is simple, but active substance is improperly distributed in bending zones causing lithium precipitation and reduced performance
Solution Approach 1:
The patent applies local quality by making the active substance layer thickness non-uniform specifically in the bending zone. The active substance layer thickness in the bending zone is set to be greater than in the flat zone, creating a locally optimized structure that prevents lithium precipitation during winding while maintaining overall manufacturing feasibility.
2Reliability
If active substance layer thickness is increased in bending zones, then lithium precipitation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-designing the active substance layer with different thicknesses in different zones before the winding process. The active substance layer is formed with greater thickness in bending zones and lesser thickness in flat zones in advance, so that during winding, the thicker bending zone material prevents lithium precipitation without requiring real-time adjustment during manufacturing.
3Quantity of substance
If electrode plates are wound tightly, then energy density is improved, but active substance distribution becomes improper causing lithium precipitation
Solution Approach 1:
The patent resolves this contradiction by applying local quality to the active substance layer thickness distribution. The bending zone, which experiences compressive stress during tight winding, is given greater active substance layer thickness to prevent lithium precipitation, while the flat zone maintains lesser thickness to maximize energy density. This localized differentiation allows tight winding while preventing improper active substance distribution.
Data Source
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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. At least one innermost bending portion in the negative electrode plate is a first bending portion, and an active substance capacity per unit area in an outer part of the first bending portion is greater than an active substance capacity per unit area in an inner part of the first bending portion; and/or at least one innermost bending portion in the positive electrode plate is a second bending portion, and an active substance capacity per unit area in an outer part of the second bending portion is greater than an active substance capacity per unit area in an inner part of the second bending portion. With such structure, active substance is more properly distributed in at least partial zones of the electrode plates in the electrode assembly, which is more cost-efficient.