Porous Solid Electrolyte Sheet for Thin Self-Supporting Batteries
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Solution Overview
Problem
Conventional solid electrolyte sheets for lithium ion solid state batteries are either too thick, leading to potential short circuits, or use materials with poor heat resistance and inadequate thickness for high energy density.
Innovation Solution
A solid electrolyte sheet with a support having a porosity of 60% to 95% and a thickness of 5 μm to 20 μm, made from heat-resistant fibers like aramid or Al2O3, filled with a lithium ion-conducting sulfide-based electrolyte, such as Li2S—P2S5, to maintain self-supporting properties and enhance ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the solid electrolyte sheet thickness is reduced to improve energy density, then the energy density increases, but the sheet loses self-supporting property and causes short circuits
Solution Approach 1:
The patent employs a porous support structure with controlled porosity (30-80%) that provides mechanical strength and self-supporting properties even at reduced thickness (10-20 μm). The porous structure allows adequate lithium ion transport while maintaining structural integrity to prevent short circuits between electrodes.
Solution Approach 2:
The patent uses a composite structure combining a porous support (such as porous polyolefin or heat-resistant fiber) with a solid electrolyte layer. This composite approach allows the thin sheet to maintain self-supporting properties through the support structure while achieving high energy density through reduced overall thickness.
2Ease of manufacture
If conventional polyethylene terephthalate is used for the support, then the manufacturing is easy, but the heat resistance is insufficient
Solution Approach 1:
The patent changes the material parameters of the support by selecting heat-resistant materials such as heat-resistant fibers (aramid, polyphenylene sulfide, polyether ether ketone) or porous ceramics instead of conventional polyethylene terephthalate. This material substitution maintains manufacturability while significantly improving heat resistance to enable high-temperature processing.
3Quantity of substance
If the support thickness is reduced below 10 μm to improve energy density, then the energy density increases, but the sheet becomes too thin to maintain structural integrity
Solution Approach 1:
The patent utilizes porous support materials with optimized pore structure that provide high specific strength. The porous structure allows the support to maintain adequate mechanical strength and structural integrity at thicknesses of 10-20 μm, preventing sheet rupture while enabling high energy density.
Solution Approach 2:
The patent employs hot pressing or sintering processes that rapidly consolidate the solid electrolyte and support structure, creating a mechanically robust thin film in one step. This rushed consolidation process achieves sufficient structural integrity at thin dimensions without requiring gradual thickness reduction.
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 provides a self-supporting, thin, and flexible solid electrolyte sheet that prevents short circuits, improves heat resistance, and enhances the energy density of solid state batteries while allowing high-temperature processing without interfacial resistance issues.
Implementation Method 1
The solid electrolyte layer has a function of conducting lithium ions
Implementation Method 2
the support has a porosity of 60% or more and 95% or less and a thickness of 5 μm or more and less than 20 μm
Data Source
AI summary
Provided is a solid electrolyte sheet having a self-supporting property while having a small thickness and flexibility. The solid electrolyte sheet is formed using a support having a specific porosity and a specific thickness. Specifically, the solid electrolyte sheet is formed in which a solid electrolyte is filled in a support having a porosity of 60% or more and 95% or less and a thickness of 5 μm or more and less than 20 μm.