Electrode Assembly Loading Profile for Mid-Region Lithium Plating
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Solution Overview
Problem
Lithium-ion batteries face challenges in safety due to lithium plating, which can occur during charging, especially in the middle area of the electrode plate, leading to potential abnormalities and reduced battery performance.
Innovation Solution
The electrode assembly is designed with a laminated and wound structure where the negative electrode plate has a higher active substance capacity per unit area in the main body portion compared to the edge portions, and the positive electrode plate has a lower active substance capacity per unit area in the main body portion compared to the edge portions, reducing the risk of lithium plating by optimizing the overlap and distribution of active material layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active substance capacity per unit area is increased in the middle area of the negative electrode plate to improve battery capacity, then the battery capacity is improved, but lithium plating occurs more easily leading to safety issues
Solution Approach 1:
The patent applies local quality by creating different active substance capacities in different regions of the electrode plate. Specifically, the middle area (first area) has a lower active substance capacity per unit area compared to the edge areas (second area), which prevents lithium plating in the middle region while maintaining overall battery capacity through the higher capacity edge regions.
2Ease of manufacture
If the active material layers are uniformly distributed across the electrode plate to simplify manufacturing, then manufacturing is easier, but lithium plating occurs in the middle area reducing safety
Solution Approach 1:
The patent implements local quality by designing non-uniform active material distribution where the middle area has reduced active substance capacity compared to the edge areas. This can be achieved through controlled coating processes that create different deposition rates or concentrations in different regions, maintaining manufacturing feasibility while preventing lithium plating.
Solution Approach 2:
The patent segments the electrode plate into different functional areas: a first area (middle region) with lower active substance capacity to prevent lithium plating, and second areas (edge regions) with higher active substance capacity to maintain battery capacity. This segmentation allows each region to serve its specific function while working together as a unified electrode structure.
Data Source
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AI summary
An embodiment of the present application provides an electrode assembly, a battery cell, a battery, and a manufacturing method and device for the electrode assembly, which belong to the technical field of batteries. The electrode assembly includes a negative electrode plate and a positive electrode plate. The negative electrode plate includes a negative active material layer located in the straight area, and the positive electrode plate includes a positive active material layer located in the straight area. A first direction is perpendicular to an axial direction of a winding structure. The negative active material layer includes a negative electrode main body portion and negative electrode edge portions located on both sides of the negative electrode main body portion, and an active substance capacity per unit area of the negative electrode main body portion is greater than an active substance capacity per unit area of the negative electrode edge portion; and/or, the positive active material layer includes a positive electrode main body portion and positive electrode edge portions located on both sides of the positive electrode main body portion, and an active substance capacity per unit area of the positive electrode main body portion is less than an active substance capacity per unit area of the positive electrode edge portion. The electrode assembly of this structure can effectively reduce the risk of lithium plating and improve the safety of the battery.