All-Solid Battery Electrolyte Powder for Thin Layers and Ionic Conductivity
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Solution Overview
Problem
When the particle diameter of the solid electrolyte powder in all solid batteries is excessively small, the ratio of crystal grain boundary in the fired solid electrolyte layer increases, leading to degraded ionic conductivity.
Innovation Solution
The use of solid electrolyte powder with specific particle diameter ranges (D10%: 0.05 μm to 0.6 μm, D50%: 0.08 μm to 1.5 μm, D90%: 4 μm or less) and a BET value of 3 m2/g to 20 m2/g, which allows for a balanced thickness of the solid electrolyte layer and maintains adequate ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the particle diameter of solid electrolyte powder is reduced to decrease solid electrolyte layer thickness, then battery capacity is improved, but ionic conductivity is degraded due to increased crystal grain boundary ratio
Solution Approach 1:
The invention changes the particle size parameters of solid electrolyte powder to a specific range (D10%: 0.05-0.6 μm, D50%: 0.08-1.5 μm, D90%: 4 μm or less) with controlled BET surface area (3-20 m2/g). This parameter optimization allows achieving thin solid electrolyte layers while maintaining adequate ionic conductivity by balancing particle packing density and crystal grain boundary formation.
2Volume of moving object
If the particle diameter of solid electrolyte powder is excessively small, then the solid electrolyte layer thickness is reduced, but the ratio of crystal grain boundary increases
Solution Approach 1:
The invention optimizes particle size parameters (D10%, D50%, D90%) and BET surface area to control crystal grain growth during firing. By maintaining particles within specific size ranges, the invention achieves thin layer thickness while controlling crystal grain boundary formation, preventing excessive grain boundary ratios that would occur with excessively fine particles.
3Manufacturing precision
If the BET value of solid electrolyte powder is increased to improve green sheet smoothness, then manufacturing precision is improved, but particle diameter becomes excessively small leading to degraded ionic conductivity
Solution Approach 1:
The invention establishes an optimal BET surface area range (3-20 m2/g) that balances green sheet smoothness and ionic conductivity. This parameter control ensures adequate particle fineness for smooth sheet formation while preventing excessive fineness that would cause high crystal grain boundary ratios and degraded ionic conductivity after firing.
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
This approach enables the achievement of favorable battery capacity and ionic conductivity in all solid batteries by optimizing the particle size distribution and surface area of the solid electrolyte powder.
Implementation Method 1
the solid electrolyte layer is a sintered structure of solid electrolyte powder
Implementation Method 2
the solid electrolyte layer is provided on a collector
Data Source
AI summary
An all solid battery includes: an oxide-based solid electrolyte layer; a first electrode provided on a first main face of the solid electrolyte layer; a second electrode provided on a second main face of the solid electrolyte layer, wherein the solid electrolyte layer is a sintered structure of solid electrolyte powder, wherein the solid electrolyte powder has D10% diameter of 0.05 μm or more and 0.6 μm or less, D50% diameter of 0.08 μm or more and 1.5 μm or less, D90% diameter of 4 μm or less, and a BET value of 3 m2/g or more and 20 m2/g or less.