Electrode Assembly Capacity Gradient for Mid-Area Lithium Plating
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Solution Overview
Problem
Lithium plating is a safety concern in rechargeable batteries, particularly in the middle area of the electrode plates, leading to issues with electrolyte infiltration and increased risk of lithium plating on the negative electrode.
Innovation Solution
The electrode assembly design includes a negative and positive electrode plate structure where the negative electrode main body portion has a higher active substance capacity per unit area than the edge portion, and the positive electrode main body portion has a lower capacity per unit area than the edge portion, with overlapping areas configured to minimize lithium plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active substance capacity per unit area is increased in the middle area of the negative electrode plate, then the risk of lithium plating is reduced, but the active substance capacity per unit area in the edge area becomes insufficient
Solution Approach 1:
The patent applies local quality by differentiating the active substance capacity per unit area between different regions of the electrode plate. Specifically, the middle area (first area) has a higher active substance capacity per unit area than the edge area (second area), allowing each region to be optimized for its specific functional requirements - the middle area for preventing lithium plating and the edge area for maintaining sufficient capacity
Solution Approach 2:
The electrode plate is segmented into distinct regions (middle area and edge area) with different active substance capacity characteristics. This segmentation allows independent optimization of each region's capacity to address the conflicting requirements of lithium plating prevention and sufficient capacity maintenance
2Reliability
If the active substance capacity per unit area is decreased in the middle area of the positive electrode plate, then the lithium plating risk is reduced, but the overall capacity of the positive electrode plate is compromised
Solution Approach 1:
The positive electrode plate applies local quality by creating a capacity gradient where the middle area (first area) has lower active substance capacity per unit area compared to the edge area (second area). This local differentiation prevents lithium plating in the middle area while maintaining sufficient overall capacity through the higher capacity edge regions
3Reliability
If the electrode plate structure is optimized to prevent lithium plating, then battery safety is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent implements parameter changes by adjusting the active substance capacity per unit area as a key parameter across different regions of the electrode plate. This approach achieves safety improvement through a relatively simple parameter modification rather than complex structural changes, maintaining manufacturability while enhancing battery safety
Data Source
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. The electrode assembly of this structure can effectively reduce the risk of lithium plating and improve the safety of the battery.