All-Solid Battery Margin Layers for Blocking Unwanted Ion Conduction
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Solution Overview
Problem
All solid batteries face issues with unexpected cell reactions due to ion conduction in margin and cover layers when stacked, as these layers can mutually diffuse with the solid electrolyte layer, leading to performance degradation and reduced capacity density.
Innovation Solution
The battery design incorporates margin and cover layers with a main component of solid electrolyte having lower ionic conductivity than the solid electrolyte layer, specifically using oxide-based materials with reduced Zr ratios to minimize diffusion and conduction, thereby suppressing unwanted cell reactions and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the margin layer is made of a material with the same composition as the solid electrolyte layer to prevent mutual diffusion, then mutual diffusion between layers is suppressed, but unexpected cell reactions occur through the margin layer due to ion conduction
Solution Approach 1:
The patent applies local quality by differentiating the ionic conductivity property between the solid electrolyte layer and the margin layer. The solid electrolyte layer maintains high ionic conductivity for battery operation, while the margin layer uses solid electrolyte material with lower ionic conductivity to prevent both mutual diffusion and unwanted cell reactions. This localized property differentiation resolves the contradiction between compositional stability and cell reaction stability.
2Stability of the object's composition
If the cover layer is made of a material with the same composition as the solid electrolyte layer to prevent mutual diffusion during firing, then mutual diffusion is suppressed, but unexpected cell reactions occur through the cover layer due to ion conduction when cell units are stacked
Solution Approach 1:
The patent applies local quality by assigning different ionic conductivity characteristics to the cover layer compared to the solid electrolyte layer. The cover layer uses solid electrolyte material with lower ionic conductivity to simultaneously achieve compositional stability during firing and prevent cell reactions between stacked cell units, while the main solid electrolyte layer retains high ionic conductivity for battery function.
3Productivity
If multiple cell units are stacked to improve capacity density, then capacity density is improved, but unexpected cell reactions occur through cover layers due to ion conduction
Solution Approach 1:
The patent uses the cover layer as an intermediary between stacked cell units. By making the cover layer material have lower ionic conductivity than the solid electrolyte layer, it acts as a blocking barrier that prevents ion conduction between adjacent cell units, thereby suppressing unwanted cell reactions while allowing the stacking configuration to maintain high capacity density.
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 design effectively suppresses mutual diffusion and unexpected cell reactions, improving the operational stability and capacity density of the all solid battery by reducing ionic conductivity in the margin and cover layers, ensuring reliable performance even when terminals are connected in reversed states.
Implementation Method 1
a solid electrolyte layer; a positive electrode layer provided on a first face of the solid electrolyte layer
Implementation Method 2
a main component of the first margin layer and the second margin layer is solid electrolyte of which ionic conductivity is lower than that of the solid electrolyte layer
Data Source
AI summary
An all solid battery includes: a solid electrolyte layer; a positive electrode layer provided on a first face of the solid electrolyte layer, a part of the positive electrode layer extending to a first edge portion of the solid electrolyte layer; a first margin layer that is provided on an area of the solid electrolyte layer where the positive electrode is not provided; a negative electrolyte layer provided on a second face of the solid electrolyte layer, a part of the negative electrolyte layer extending to a second edge portion of the solid electrolyte layer; a second margin layer that is provided on an area of the second face of the solid electrolyte layer where the negative electrolyte layer is not provided; wherein a main component of the first margin layer and the second margin layer is solid electrolyte of which ionic conductivity is lower than that of the solid electrolyte layer.