Solid Electrolyte Membrane Composition for Crack-Resistant Densification
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Solution Overview
Problem
The brittleness of solid electrolyte membranes increases during the densification process in large-area and mass production, leading to microcracks and fractures, which affect the battery cell assembly process.
Innovation Solution
A solid electrolyte membrane is developed using a high-molecular-weight polymer binder and a low-molecular-weight non-polar liquid rubber as a plasticizer, improving the membrane's flexibility and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solid electrolyte membrane is subjected to pressing and drying processes to reduce pores and increase density, then the manufacturing efficiency and membrane density are improved, but the brittleness of the solid electrolyte rapidly increases, resulting in microcracks or fractures
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte membrane by incorporating a polymer binder and plasticizer in specific ratios. This modifies the physical properties of the membrane, making it more flexible and resistant to cracking during pressing while maintaining manufacturing efficiency.
Solution Approach 2:
The patent creates a composite solid electrolyte membrane by combining multiple materials: solid electrolyte particles, polymer binder, and plasticizer. This composite structure provides both the ionic conductivity of the solid electrolyte and the flexibility of the polymer-plasticizer matrix, preventing microcracks during pressing operations.
2Volume of stationary object
If the solid electrolyte membrane is subjected to pressing processes to increase density, then the membrane density is improved, but the flexibility of the membrane deteriorates due to increased brittleness
Solution Approach 1:
The patent modifies the physical and chemical parameters of the membrane by adding plasticizer (5-20 wt%) which lowers the glass transition temperature and increases chain mobility of the polymer matrix. This allows the membrane to maintain flexibility even at high densities after pressing.
Solution Approach 2:
The polymer binder acts as an intermediary material between the rigid solid electrolyte particles. It provides a flexible matrix that binds the particles together while accommodating density changes during pressing, preventing direct stress concentration that would cause cracking.
3Ease of manufacture
If a conventional polymer binder is used in the solid electrolyte membrane, then the membrane can be formed, but the membrane exhibits insufficient flexibility and high brittleness after pressing
Solution Approach 1:
The patent changes the molecular weight parameter of the polymer binder, specifying a range of 75,000-1,000,000 g/mol. This high molecular weight provides long polymer chains that entangle and provide flexibility, while the specified ratio (3-20 wt%) ensures sufficient binding without excessive rigidity.
Solution Approach 2:
The plasticizer serves as an intermediary that modifies the polymer binder's properties. It penetrates the polymer matrix, increases free volume, and enhances chain mobility, thereby improving flexibility without compromising the binder's adhesion function.
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 improved flexibility and density of the solid electrolyte membrane reduce the occurrence of microcracks and fractures, enhancing the stability of all-solid-state secondary batteries.
Implementation Method 1
a low-molecular-weight non-polar liquid rubber (non-polar elastomer), wherein the low-molecular-weight non-polar liquid rubber has a weight average molecular weight of about 2,000 g/mol to about 75,000 g/mol, and a viscosity of about 1 centipoises (cps) to about 100,000 cps
Data Source
AI summary
A solid electrolyte membrane includes a solid electrolyte, a high-molecular-weight polymer binder having a weight average molecular weight of about greater than 75,000 gram/mole (g/mol) but less than or equal to 1,000,000 g/mol, and a low-molecular-weight non-polar liquid rubber (non-polar elastomer), wherein the low-molecular-weight non-polar liquid rubber has a weight average molecular weight of about 2,000 g/mol to about 75,000 g/mol, and a viscosity of about 1 centipoises (cps) to about 100,000 cps. An all-solid-state secondary battery includes the solid electrolyte membrane.