Method for producing all solid state battery
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Solution Overview
Problem
All solid state batteries using precipitation-dissolution reactions of metallic Li face challenges in suppressing short circuits due to dendrite growth, particularly when the filling ratio of the separator is low, leading to insufficient suppression of short circuits.
Innovation Solution
A method for producing all solid state batteries with high packing ratio separators involves preparing a sulfide solid electrolyte represented by Li7-aPS6-aXa, dissolving it in an alcohol-based solvent to form a liquid composition, applying it to an anode current collector, and drying to form a separator with a sulfide solid electrolyte ratio of 10% to 30% by weight, ensuring high filling ratios and reduced voids for dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the filling ratio of the separator is low, then the manufacturing process is simpler, but dendrites grow along grain boundaries and voids are created, leading to short circuits
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating halogen elements (Cl, Br, I) into the Li-PS system, forming Li7-aPS6-aXa compounds. This compositional modification enables the separator to achieve high filling ratio (≥90%) while maintaining manufacturability through controlled precipitation-dissolution reactions of metallic Li during battery operation.
Solution Approach 2:
The patent creates a composite solid electrolyte system by combining Li-PS base material with halogen-containing compounds (LiCl, LiBr, LiI). This composite approach produces a separator with enhanced packing density and reduced voids, achieving both high filling ratio and reliable short circuit suppression while remaining manufacturable.
2Reliability
If the filling ratio of the separator is increased to suppress dendrites, then short circuit suppression improves, but the manufacturing complexity increases
Solution Approach 1:
The patent utilizes the self-service mechanism where metallic Li precipitation-dissolution reactions during battery operation automatically adjust and optimize the separator structure. The Li metal naturally fills voids and enhances packing density during normal battery cycling, achieving high filling ratio without complex external manufacturing processes.
Solution Approach 2:
The patent incorporates halogen-containing compounds into the solid electrolyte composition in advance, which then react with Li metal during initial battery cycles to form LiX compounds (LiCl, LiBr, LiI). This preliminary incorporation of reactive precursors simplifies manufacturing while achieving the desired high filling ratio structure during battery operation.
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 method effectively produces all solid state batteries with high-fill separators, suppressing short circuits and enhancing battery characteristics such as cyclic performance by maintaining a high packing ratio and reducing Li ion conductivity issues.
Implementation Method 1
a liquid composition preparation step, which is a step of dissolving the sulfide solid electrolyte in an alcohol-based solvent to prepare a liquid composition
Implementation Method 2
a separator formation step, which is a step of forming a separator by volatilizing the alcohol-based solvent from the coating layer by drying
Implementation Method 3
A method for producing an all solid state battery using a precipitation-dissolution reaction of metallic Li as a reaction of an anode
Data Source
AI summary
A method for producing an all solid state battery using a precipitation-dissolution reaction of metallic Li as a reaction of an anode, includes a preparation step, a liquid composition preparation step, a coating layer formation step, and a separator formation step. The preparation step includes preparing a sulfide solid electrolyte represented by Li7-aPS6-aXa (X is at least one of Cl, Br, and I, and a satisfies 0≤a≤2), the liquid composition preparation step includes dissolving the sulfide solid electrolyte in an alcohol-based solvent to prepare a liquid composition, the coating layer formation step includes applying the liquid composition to an anode current collector to form a coating layer, the separator formation step includes forming a separator by volatilizing the alcohol-based solvent from the coating layer by drying, and the ratio of the sulfide solid electrolyte contained in the liquid composition is 10% by weight to 30% by weight.