Method for producing solid electrolyte membrane, method for producing all-solid-state battery, apparatus for producing solid electrolyte membrane, and apparatus for producing all-solid-state battery

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Solution Overview

Problem

Existing methods for manufacturing solid electrolyte membranes for all-solid-state batteries face issues such as inferior electrical conduction due to small contact areas between powder materials, complexity in forming thin film sheets, use of harmful organic solvents, and low durability due to thick electrolyte layers and high resistance between electrodes.

Innovation Solution

A method involving the formation of a non-woven fabric using laser electrospinning, where a slurry containing solid electrolyte particles is applied, dried, and pressed onto the fabric, creating a thin, high-strength solid electrolyte membrane with improved contact area and reduced thickness, using a resin-based extruder and laminate manufacturing machine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a slurry is prepared by mixing inorganic particles and organic binder in a specific solvent and then dried, then solid electrolyte membrane can be produced, but organic solvent residue remains in the membrane causing safety issues and performance degradation

Engineering Contradiction:
Improvesafety of all-solid-state batteryVSAvoidorganic solvent residue
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the fundamental parameter of the solvent system by replacing organic solvents with water as the processing solvent. This parameter change eliminates the safety issues and performance degradation caused by organic solvent residues while maintaining the effectiveness of the slurry preparation and membrane formation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the chemical system (organic solvents) with a different chemical system (water-based solvents). This substitution replaces potentially harmful organic chemicals with safe aqueous solutions, achieving the same slurry preparation and membrane formation functions without the harmful residues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If polyvinylidene fluoride is used as organic binder, then slurry preparation is easy, but the binder degrades at high temperature during sintering process

Engineering Contradiction:
Improveslurry preparation easeVSAvoidbinder stability at high temperature
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the chemical composition parameter of the binder by replacing polyvinylidene fluoride with water-soluble polymers such as polyvinyl alcohol, carboxymethyl cellulose, or starch. These alternative binders maintain ease of slurry preparation through water solubility while providing superior thermal stability during the sintering process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the fluoropolymer binder system with a water-soluble polymer system. This substitution maintains the ease of manufacture advantage through simple aqueous processing while eliminating the high-temperature degradation problem inherent in polyvinylidene fluoride.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If organic binder is used in slurry, then green strength is sufficient, but harmful volatile organic compounds are generated during drying and sintering

Engineering Contradiction:
Improvegreen strength of membraneVSAvoidvolatile organic compounds
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes organic binder materials with water-soluble polymer binders. This substitution eliminates the generation of harmful volatile organic compounds during drying and sintering while maintaining adequate green strength through the adhesive properties of water-soluble polymers like polyvinyl alcohol and carboxymethyl cellulose.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the potential weakness of water-soluble binders (lower green strength compared to organic binders) into an advantage by eliminating harmful VOC emissions. The water-based system provides sufficient green strength for handling while being environmentally benign and safe during subsequent processing.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Manufacturing precision

If multiple production steps including slurry preparation, coating, drying, and sintering are performed, then solid electrolyte membrane can be formed, but production time is lengthy

Engineering Contradiction:
Improvemembrane formation qualityVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by incorporating porosity-forming agents into the slurry before coating. This pre-preparation step ensures that the desired porous structure is formed during a single sintering cycle, eliminating the need for multiple sequential steps and significantly reducing production time while maintaining membrane quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges multiple functions into a single sintering step. The sintering process simultaneously achieves binder removal, membrane densification, and porosity formation through the decomposition of porosity-forming agents. This consolidation of functions reduces the total number of production steps and accelerates manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

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 approach results in a solid electrolyte membrane with enhanced output characteristics, reduced resistance, and improved durability, facilitating the efficient production of all-solid-state batteries with improved charge/discharge performance.

Implementation Method 1

a scaffold structure formed by inorganic particles

Methodology Applied
Scientific EffectScaffold structure formation:

Implementation Method 2

solid electrolyte membrane with a specific porous structure

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3961776A1Method for producing solid electrolyte membrane, method for producing all-solid-state battery, apparatus for producing solid electrolyte membrane, and apparatus for producing all-solid-state battery
Publication Date: 2022.03.02 THE JAPAN STEEL WORKS LTD
  • EP3961776A1 patent drawingFigure 1
  • EP3961776A1 patent drawingFigure 2(a)~2(c)
  • EP3961776A1 patent drawingFigure 3~4(c)

AI summary

A method of manufacturing an all-solid-state battery and an apparatus for manufacturing the same are provided. The method of manufacturing the all-solid-state battery includes: (a) a step of forming a non-woven fabric having a fiber made of a resin; (b) a step of applying a slurry containing solid electrolyte particles onto the non-woven fabric; (c) a step of drying the slurry on the non-woven fabric by a heater; (d) a step of pressurizing the slurry on the non-woven fabric by a roller; (e) a step of forming a positive electrode member on one surface of the solid electrolyte membrane; and (f) a step of forming a negative electrode member on the other surface of the solid electrolyte membrane. The step (a) is a step of forming the non-woven fabric by making a resin containing a polar filler fibrous by a laser electrospinning method. By such a method, the all-solid-state battery (a laminated body of a positive electrode member, a solid electrolyte membrane, and a negative electrode member) can be efficiently manufactured.