Positive Electrode Plate Layout to Limit Edge Lithium Plating
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Solution Overview
Problem
Lithium-ion batteries face challenges in increasing energy density while preventing edge lithium precipitation at the negative electrode, which degrades battery performance.
Innovation Solution
A positive electrode plate with a first active material layer in the middle region and a second active material layer at the edges, where the specific capacity of the first active material is greater than the second active material, optimizing the distribution to alleviate edge lithium precipitation and enhance cycling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If surface density of electrode plates is increased to improve energy density, then energy density is improved, but edge lithium precipitation of negative electrode plate occurs causing performance deterioration
Solution Approach 1:
The positive electrode plate employs different active materials with different specific capacities in different regions: the first active material layer with higher specific capacity is positioned in the middle region, while the second active material layer with lower specific capacity is positioned at the edge regions. This local differentiation optimizes lithium ion distribution and prevents edge lithium precipitation, allowing high energy density to be achieved without performance deterioration
Solution Approach 2:
The positive electrode active material layer is segmented into multiple regions with different materials and capacities. The edge regions use second active material with lower specific capacity to prevent lithium precipitation, while the middle region uses first active material with higher specific capacity to maximize energy density. This segmentation strategy resolves the contradiction between energy density and performance stability
Data Source
AI summary
Disclosed are a positive electrode plate and a battery including the same. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer disposed on either or both sides of the current collector. The positive electrode active material layer includes a first active material layer located in a middle region of a surface of the positive electrode current collector along a length direction and a second active material layer located at edges. A specific capacity of the first active material in the first active material layer is greater than that of the second active material in the second active material layer.