Porous Solid Electrolyte Sheet for Thin Crack-Resistant Batteries
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Solution Overview
Problem
Solid-state batteries face challenges in achieving high strength for thinner electrolyte sheets to prevent cracking and shorting, especially during high-pressure pressurization and mass production, which affects energy density and safety.
Innovation Solution
A solid electrolyte sheet with a porous base material, a solid electrolyte material filling voids, and a binder content of at least 10% by mass, providing improved strength and preventing cracking, while allowing for a thinner design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the solid electrolyte sheet is made thinner to improve energy density, then the energy density is improved, but the strength is reduced causing cracks and shorting
Solution Approach 1:
The patent applies composite materials by combining a porous base material (providing structural framework), solid electrolyte material (providing ion conduction), and binder (providing adhesion and strength). This composite structure enables the sheet to be thinner while maintaining sufficient strength to prevent cracking and shorting, thereby improving energy density without sacrificing mechanical integrity.
Solution Approach 2:
The patent uses a porous base material as the foundation of the solid electrolyte sheet. The porous structure provides both mechanical support and pathways for ion transport. By optimizing the porosity and pore size distribution, the sheet achieves high ion conductivity while maintaining structural strength even at reduced thickness, resolving the contradiction between thinness for energy density and strength for crack prevention.
2Strength
If the amount of binder is increased to improve strength during pressurization, then the strength is improved, but the ion conductivity is reduced
Solution Approach 1:
The patent optimizes the binder content parameter to a specific range (5-20 mass%, preferably 8-15 mass%). This parameter optimization ensures sufficient strength during high-pressure pressurization in roll presses while maintaining adequate ion conductivity. The precise control of binder quantity resolves the contradiction between needing enough binder for mechanical strength and limiting binder to preserve ion conduction pathways.
Solution Approach 2:
The patent distributes the binder locally within the composite structure, adhering to the base material and solid electrolyte particles at critical interfaces. This local concentration of binder provides strength where needed during pressurization while leaving other regions with higher ion conductivity. The non-uniform distribution of binder functionality resolves the contradiction between localized strength requirements and overall ion conductivity.
3Productivity
If a roll press is used for mass production pressurization, then productivity is improved, but anisotropic deformation occurs causing shorting
Solution Approach 1:
The composite structure with porous base material, solid electrolyte, and binder creates a mechanically robust sheet that can withstand the anisotropic deformation forces of roll press manufacturing. The interconnected porous network and binder matrix distribute stresses uniformly, preventing the sheet from deforming unevenly during high-speed mass production pressurization, thus maintaining manufacturing precision while achieving high productivity.
Solution Approach 2:
The patent performs preliminary formation of the composite structure with optimized binder adhesion before the final pressurization step. This preliminary structuring ensures that when the sheet undergoes rapid pressurization in roll presses during mass production, the deformation is more uniform and controlled, preventing shorting while maintaining the productivity benefits of roll press technology.
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
The solution results in a solid electrolyte sheet with enhanced strength, preventing cracking and improving lithium ion conductivity, leading to increased energy efficiency and charge-discharge capacity in solid-state batteries.
Implementation Method 1
a solid electrolyte material filling voids in the base material
Implementation Method 2
a binder adhering to the base material
Implementation Method 3
a solid electrolyte layer is interposed between a positive electrode and a negative electrode. The solid electrolyte layer functions to conduct lithium ions
Data Source
AI summary
To provide a solid electrolyte sheet with high strength that allows for a thinner sheet, and a solid-state battery provided with such a solid electrolyte sheet. A solid electrolyte sheet 31 is provided with a porous base material 33, a solid electrolyte material filling voids in the base material 33, and a binder adhering to the base material 33, wherein when 100% by mass is taken to mean an entirety of the solid electrolyte sheet 31, content of the binder is equal to or higher than 10% by mass. A solid-state battery 1 is provided with a positive electrode layer 11, a negative electrode layer 21, and a solid electrolyte layer 30 located between the positive electrode layer 11 and the negative electrode layer 21, wherein the solid electrolyte layer includes the solid electrolyte sheet 31.