Negative Electrode Filler Gradient for Battery Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional negative electrodes with a two-layer structure experience non-uniform electrolyte distribution due to differing volume change ratios during charge and discharge, leading to increased battery resistance, especially during high-speed charge-discharge cycles.
Innovation Solution
A negative electrode with a mixture layer comprising graphite particles, solid inorganic fillers, and hollow inorganic fillers, where the first region (near the current collector) has a higher volume change ratio and more solid filler, and the second region (opposite side) has a lower volume change ratio and more hollow filler, optimizing filler content to suppress electrolyte exudation and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a two-layer structure with compound layer and carbon material layer is used to increase capacity, then the battery capacity is improved, but the electrolyte distribution becomes non-uniform due to different volume change ratios, leading to increased battery resistance
Solution Approach 1:
The patent applies local quality by creating three distinct regions within the negative electrode mixture layer, each with different filler compositions tailored to their specific volume change characteristics. The first region (near current collector) contains more solid filler to handle high expansion, the second region (intermediate) has balanced filler content, and the third region (outer surface) contains more hollow filler to manage contraction. This localized optimization of filler distribution ensures uniform electrolyte distribution across all regions while maintaining high battery capacity.
2Productivity
If high-speed charge and discharge is repeated, then the power output is improved, but the battery resistance increases due to electrolyte non-uniformity
Solution Approach 1:
The patent applies parameter changes by systematically varying the filler composition parameters across different regions of the negative electrode. The solid filler content and hollow filler content are adjusted as gradient parameters from the current collector side to the outer surface, creating an optimized parameter distribution that maintains low battery resistance even during repeated high-speed charge-discharge cycles.
Data Source
AI summary
This negative electrode comprises an electrode current collector, and an electrode mixture layer provided on a surface of the electrode current collector. When, with respect to the thickness direction of the electrode mixture layer, a range from the surface on the side of the electrode current collector to 40% of the thickness of the electrode mixture layer is defined as a first region, and a range from the surface on the side opposite to the electrode current collector to 40% of the thickness of the electrode mixture layer is defined as a second region, the first region and the second region have different volume change ratio upon charge and discharge, and the region having the larger volume change ratio upon charge and discharge has a higher content of a solid inorganic filler and a lower content of a hollow inorganic filler than the region having the smaller volume change ratio.