Positive Electrode Particle-Size Mixing for Battery Kinetics
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Solution Overview
Problem
Mixing positive electrode active materials with significantly different particle sizes results in poor kinetic performance of lithium-ion batteries, despite potential increases in energy density.
Innovation Solution
A positive electrode plate design incorporating a combination of positive electrode active materials with large and small particle sizes, optimized in mass proportion and layering, to enhance energy density and mitigate impedance deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If positive electrode active materials with significantly different particle sizes are mixed in similar amounts, then energy density is improved, but kinetic performance deteriorates
Solution Approach 1:
The patent applies local quality by creating different particle size distributions in different regions of the positive electrode active material layer. Specifically, it defines a first particle size distribution in a first region and a second particle size distribution in a second region, with the ratio of average particle sizes between corresponding regions being controlled within 0.5 to 2.0. This spatial variation in particle size characteristics allows different regions to contribute differently to energy storage and kinetic performance, resolving the contradiction between energy density and kinetic performance.
Solution Approach 2:
The patent employs parameter changes by systematically varying the particle size distribution parameters across different regions of the active material layer. By controlling the ratio of average particle sizes (R1/R2) between 0.5 and 2.0, and defining specific particle size distributions in different regions, the patent optimizes both the quantity of active material (energy density) and the electrochemical response characteristics (kinetic performance) without compromising either parameter.
2Ease of manufacture
If a single type of positive electrode active material is used, then manufacturing is simple, but energy density and safety performance are limited
Solution Approach 1:
The patent applies composite materials by combining positive electrode active materials with different particle size distributions in a controlled manner. Rather than using a single uniform material, it creates a composite structure where materials with different particle sizes are distributed across different regions of the positive electrode, achieving enhanced energy density while maintaining manufacturing feasibility through defined spatial arrangements.
Solution Approach 2:
The patent uses segmentation by dividing the positive electrode active material layer into distinct regions (first region and second region) with different particle size distributions. This segmentation allows each region to be optimized for specific functions while maintaining overall manufacturing simplicity through systematic arrangement of the segmented structures.
Data Source
AI summary
A positive electrode plate, a battery, and an electric apparatus. The positive electrode plate includes a current collector and an active material layer disposed on at least one side surface of the current collector. In a mixed active material layer, a positive electrode active material includes a first positive electrode active material and a second positive electrode active material, an average particle size R2 of the second positive electrode active material is greater than an average particle size R1 of the first positive electrode active material, R2/R1≥2, and the first positive electrode active material or the second positive electrode active material accounts for 55% to 95% of a total mass of the positive electrode active material in the mixed active material layer.