Lithium Battery Anode Alignment to Suppress Edge Plating
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Solution Overview
Problem
Lithium secondary batteries face issues with lithium precipitation at the negative electrode active layer due to a reversed N/P ratio, leading to dendrite formation and safety concerns, especially under high-rate conditions, and increasing the negative electrode active material loading worsens rapid charging characteristics.
Innovation Solution
A negative electrode with a carbon-based active layer divided into a center, edge, and sliding region, where the alignment of the carbon-based material in each region satisfies specific ratios, and a manufacturing method involving a magnetic field application to achieve optimal orientation and thickness gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative electrode active material loading amount is increased to suppress lithium precipitation, then the safety is improved, but the rapid charging characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a thickness gradient in the negative electrode active layer, where the loading amount varies across different regions. The edge region has higher active material loading to suppress lithium precipitation, while the center region maintains lower loading to preserve rapid charging characteristics. This spatial variation in material distribution allows simultaneous optimization of safety and charging performance.
Solution Approach 2:
The patent segments the negative electrode active layer into distinct regions (edge region and center region) with different thickness characteristics. This segmentation enables independent optimization of each region's properties, allowing the edge region to focus on lithium precipitation suppression while the center region maintains fast ion transport pathways for rapid charging.
2Reliability
If the negative electrode active material loading amount is increased to suppress lithium precipitation, then the N/P ratio is improved, but the lithium ion travel distance increases
Solution Approach 1:
The patent implements local quality by creating a thickness gradient where the edge region has higher active material loading to improve the N/P ratio and suppress lithium precipitation, while the center region maintains lower loading to minimize lithium ion travel distance. This localized variation in material distribution allows the system to achieve improved N/P ratio without proportionally increasing ion transport path lengths.
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 prevents lithium precipitation and maintains excellent rapid charging performance by controlling lithium ion travel distance and adhesion, enhancing safety and energy density.
Implementation Method 1
a manufacturing method involving the application of a magnetic field to align the material effectively
Data Source
AI summary
A negative electrode for a lithium secondary battery includes a negative electrode active layer divided into a center region, an edge region, and a sliding region on a negative electrode current collector. The lithium precipitation at the end of the negative electrode active layer can be suppressed by the alignment (O.I) of each carbon-based negative electrode active material contained in the center region, the edge region, and the sliding region satisfying Equation 1 and Equation 2. A secondary battery including the same has the advantage of excellent rapid charging performance. A method of manufacturing the negative electrode is also provided.