Segmented Negative Electrode Layout for Better Electrolyte Wetting
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Solution Overview
Problem
Existing lithium secondary batteries face issues with non-wetted areas in the negative electrode, leading to defects such as lithium precipitation and performance deterioration.
Innovation Solution
The negative electrode active material layer is designed with first and second layers having different specific capacities and densities, with the second layer having a higher specific capacity and lower density, allowing the electrolyte solution to penetrate effectively and minimize non-wetted areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform negative electrode active material layer is used, then the manufacturing process is simple, but non-wetted areas form leading to lithium precipitation and performance deterioration
Solution Approach 1:
The negative electrode active material layer is segmented into multiple sub-layers with different specific capacities arranged in an alternating pattern. This segmentation allows the electrolyte to penetrate more effectively through the electrode structure, eliminating non-wetted areas and preventing lithium precipitation while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the negative electrode active material layer are assigned different specific capacities to create local quality variations. The alternating high and low specific capacity regions facilitate better electrolyte distribution and penetration throughout the electrode, resolving the wetting issue without requiring complete structural redesign.
2Quantity of substance
If the specific capacity of the negative electrode active material layer is increased, then the energy density is improved, but the electrolyte penetration becomes insufficient creating non-wetted areas
Solution Approach 1:
The high capacity active material is segmented into alternating layers with lower capacity materials, creating a stratified structure that maintains overall high capacity while ensuring electrolyte penetration pathways are preserved throughout the electrode thickness.
Solution Approach 2:
The specific capacity parameter is varied across different layers of the negative electrode active material layer. By creating alternating regions of high and low specific capacity, the structure achieves high overall capacity while the lower capacity regions facilitate electrolyte penetration and prevent non-wetted area formation.
Data Source
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AI summary
Disclosed are a negative electrode for a lithium secondary battery, a lithium secondary battery including the same, and a method for manufacturing the lithium secondary battery. A negative electrode active includes a negative electrode current collector and a negative electrode active material layer on the negative electrode current collector, the negative electrode active material layer has a long axis in a first direction, the negative electrode active material layer includes first negative electrode active material layers spaced apart from each other in a second direction that crosses the first direction and a second negative electrode active material layer between respective ones of the first negative electrode active material layers, and a ratio of a specific capacity of the first negative electrode active material layer to a specific capacity of the second negative electrode active material layer is 0.75 to 0.95.