Positive Electrode Particle Structure for Solid-State Ion Contact
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Solution Overview
Problem
The challenge in manufacturing all-solid-state batteries is the difficulty in achieving effective physical contact between the electrode active material and the solid electrolyte due to the latter's inability to penetrate the pores of the electrode, leading to uneven distribution and reduced adhesion, which degrades battery performance.
Innovation Solution
Adjusting the size ratio of positive electrode active material particles and solid electrolyte particles to within a specific range, ensuring the solid electrolyte particles are 10 to 20% of the positive electrode active material particles, with a Span/D50 value of 0.25 micrometers or less, to enhance packing density and ion path formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte particles are used in all-solid-state batteries, then safety is improved by eliminating flammable solvents, but physical contact between electrode active material and solid electrolyte deteriorates due to inability to penetrate electrode pores
Solution Approach 1:
The patent changes the particle size parameter of solid electrolyte particles to 10-20% of the positive electrode active material particle size. This parameter change enables the solid electrolyte particles to effectively contact the electrode active material while maintaining the safety advantages of solid electrolytes.
Solution Approach 2:
The patent creates local quality differences by using bimodal or multimodal particle size distributions of solid electrolyte particles. This allows smaller particles to fill gaps and contact points between larger active material particles, ensuring effective physical contact at critical interfaces while maintaining overall structure integrity.
2Quantity of substance
If binder is dissolved in large amount of solvent for high-loading electrodes, then electrode loading is improved, but binder migration during drying process deteriorates adhesion and causes electrode unevenness
Solution Approach 1:
The patent optimizes the solvent content parameter and binder concentration parameter in the slurry formulation. By controlling these parameters, the patent achieves high electrode loading while preventing binder migration during the drying process, maintaining both adhesion and electrode uniformity.
3Quantity of substance
If particle density increases during manufacturing process, then packing efficiency is improved, but packed areas with high density cause degradation of battery performance
Solution Approach 1:
The patent creates local quality variations in particle density distribution by using bimodal or multimodal particle size distributions. This allows less dense regions to be formed in critical areas for ion transport while maintaining high overall packing efficiency, preventing performance degradation.
Data Source
AI summary
Positive electrode particles include a positive electrode active material layer having positive electrode active material particles, and a solid electrolyte layer surrounding the positive electrode active material layer, and having solid electrolyte particles, wherein the average size of the solid electrolyte particles is 10 to 20% of the average size of the positive electrode active material particles.