Current Collector Corner Holes for Lithium Plating Control
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Solution Overview
Problem
Lithium precipitation between positive and negative electrode plates in secondary batteries during cyclic charging and discharging reduces the service life due to structural design defects in electrode assemblies.
Innovation Solution
A current collector with through holes in corner regions allows lithium ions to communicate across the electrode plate, balancing concentrations and reducing the risk of precipitation, while maintaining structural strength through controlled opening areas and stress region management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through holes are provided in corner regions of the current collector, then lithium ion communication and concentration balance is improved, but structural strength may be compromised
Solution Approach 1:
The patent applies local quality by providing through holes only in the corner regions of the current collector, not uniformly across the entire structure. This localized approach allows lithium ion communication specifically where concentration imbalance occurs during bending, while preserving the structural integrity of the main current collector body. The corner regions are specifically targeted because they correspond to bent portions of the electrode assembly where lithium precipitation is most likely to occur.
Solution Approach 2:
The current collector is segmented into corner regions and non-corner regions, with through holes provided only in the corner regions. This segmentation allows the structure to have different properties in different areas: the corner regions facilitate lithium ion communication while the rest of the current collector maintains structural strength. The through holes divide the corner regions into multiple sub-regions, enabling localized functional optimization.
2Reliability
If multiple through holes are provided in corner regions, then lithium ion concentration balance is improved, but stress concentration and fracture risk increase
Solution Approach 1:
The patent applies parameter changes by carefully controlling the number, size, and distribution of through holes in the corner regions. The parameters are optimized to achieve sufficient lithium ion communication while avoiding excessive stress concentration. The through holes are spaced at specific intervals and their dimensions are controlled to balance the competing requirements of ion transport and structural integrity.
Solution Approach 2:
The patent uses partial action by providing through holes only in the corner regions rather than across the entire current collector. This partial approach is sufficient to address the lithium precipitation problem in bent portions without unnecessarily compromising the overall structural strength. The through holes are strategically placed only where needed, avoiding excessive modification of the current collector structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively balances lithium ion concentrations across the electrode plate, reducing lithium precipitation and prolonging the service life of secondary batteries by ensuring dynamic balance and structural integrity.
Implementation Method 1
lithium ions on a convex side and a concave side of the electrode plate may communicate through the through holes, thereby ensuring that intercalated lithium concentrations on two sides of the electrode plate are balanced
Data Source
AI summary
The present application relates to a current collector, an electrode plate and a preparation method thereof, an electrode assembly, and a secondary battery. Through holes running through a current collecting body are provided in at least one corner region, so that the electrode assembly formed by winding electrode plates provided with the current collectors may feature the through holes in at least one layer of electrode plate in a bent portion. In this case, during cyclic charging, lithium ions on a convex side and a concave side of the electrode plate may communicate through the through holes, thereby ensuring that intercalated lithium concentrations on two sides of the electrode plate are balanced, reducing the risk of lithium precipitation between the negative electrode plate and the positive electrode plate in the bent portion, and prolonging the service life of the secondary battery.