Inorganic Solid Electrolyte Slurry Preparation via Segmented Wet Grinding

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Solution Overview

Problem

The existing methods for preparing inorganic solid electrolyte composite slurry face challenges in reducing the particle size of large-sized powders obtained from high temperature solid phase reactions and efficiently drying ultrafine powders, leading to issues with coating thickness and grinding efficiency, which affects the safety and performance of lithium-ion batteries.

Innovation Solution

A method involving the preparation of a preparatory slurry A by mixing inorganic solid electrolyte powder with a solvent and wet grinding, followed by mixing a binder with a second solvent to form preparatory slurry B, then combining the two to create the inorganic solid electrolyte composite slurry, without the need for solvent separation, ensuring efficient grinding and preventing particle re-growth, thereby achieving a suitable particle size and coating thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the inorganic solid electrolyte powder is milled by wet grinding to reduce particle size, then the particle size is reduced, but the solvent removal becomes difficult and causes particle re-growth

Engineering Contradiction:
Improveparticle sizeVSAvoidsolvent removal
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the binder dissolution step from the conventional sequence, preparing the binder solution separately and adding it after wet grinding. This separation allows complete removal of grinding solvent without causing particle re-growth, while the binder solution is added later to form the final coating slurry.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The binder is dissolved in advance in a separate preparatory step, and the grinding solvent is removed completely before adding the binder solution. This preliminary preparation prevents the binder from interfering with the grinding process and avoids particle re-growth during solvent removal.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the binder is dissolved first and then the inorganic solid electrolyte powder is added for wet grinding, then the components are mixed, but the grinding efficiency decreases and sand mill clogging occurs

Engineering Contradiction:
Improvegrinding efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the slurry preparation into two independent segments: (1) wet grinding of inorganic solid electrolyte powder with grinding solvent to obtain ultrafine powder, and (2) separate dissolution of binder with binder solvent, followed by mixing. This segmentation eliminates the contradiction between mixing and grinding efficiency.

Inventive Principle:
Principle #1Segmentation

3Use of energy by moving object

If the coating thickness is kept thin to maintain energy density, then the battery performance is maintained, but the thermal stability and safety are insufficient

Engineering Contradiction:
Improveenergy densityVSAvoidthermal stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the particle size parameter of the inorganic solid electrolyte powder from conventional sizes (>5μm) to ultrafine sizes (D90 not more than 500nm). This parameter change allows thin coatings to provide sufficient thermal stability while maintaining high energy density, resolving the contradiction between coating thickness and safety.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces the particle size of inorganic solid electrolyte powders, enhances grinding efficiency, and ensures a thin, stable coating on lithium-ion battery components, improving battery safety and performance by preventing thermal runaway and maintaining energy density.

Implementation Method 1

mixing an inorganic solid electrolyte powder with a first solvent and wet grinding an obtained mixture to form a preparatory slurry A

Methodology Applied
Scientific EffectWet grinding: Abrasion

Implementation Method 2

mixing a binder with a second solvent to form a preparatory slurry B

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 3

mixing the preparatory slurry A with the preparatory slurry B to obtain the inorganic solid electrolyte composite slurry

Methodology Applied
Scientific EffectMixing: Stirring

Data Source

PatentEP3435446B1Inorganic solid electrolyte composite slurry, method for preparing, application and lithium-ion battery having the same
Publication Date: 2022.03.09 MICROVAST POWER SYST CO LTD
  • EP3435446B1 patent drawingFigure 1~2
  • EP3435446B1 patent drawingFigure 3~4
  • EP3435446B1 patent drawingFigure 5

AI summary

A method for preparing an inorganic solid electrolyte composite slurry includes: mixing an inorganic solid electrolyte powder with a first solvent and wet grinding an obtained mixture to form a preparatory slurry A; mixing a binder with a second solvent to form a preparatory slurry B; mixing the preparatory slurry A with the preparatory slurry B to obtain the inorganic solid electrolyte composite slurry. The inorganic solid electrolyte composite slurry prepared by the present disclosure effectively solves the problem that it is difficult to reduce the inorganic solid electrolyte powder particle size in the preparation process, or it is difficult to fully dry the inorganic solid electrolyte powder after sand milling. The present disclosure further provides an inorganic solid electrolyte composite slurry prepared by the method, an application of the inorganic solid electrolyte composite slurry, and a lithium-ion battery having the inorganic solid electrolyte composite slurry.