Sulfide Solid Electrolyte Particle Shaping via Two-Step Milling

Solution Overview

Problem

Existing methods for producing sulfide solid electrolyte particles in spherical form are inefficient due to the need for weak grinding energy, which prolongs the process and results in non-uniform distribution of conductive materials on the particle surface, affecting capacity retention in batteries.

Innovation Solution

A two-step mechanical milling process is employed, where the sulfide solid electrolyte material is first ground to form flattened particles using strong energy, followed by grinding with weak energy to achieve spherical particles, with specific kinetic energy ranges and temperatures to optimize particle size and surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If strong grinding energy is applied to obtain fine spherical particles, then particle fineness is improved, but particle shape becomes flattened and surface area increases

Engineering Contradiction:

Improveparticle finenessVSAvoidparticle shape

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The grinding process is divided into two distinct stages: a first grinding step using strong grinding energy to achieve fine particle size, and a second grinding step using weak grinding energy to restore spherical shape. This segmentation allows each stage to optimize for its specific purpose without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first grinding step performs the preliminary action of reducing particle size to the desired fineness level before the second grinding step adjusts the shape. By preparing the particles with the correct size first, the subsequent shaping step can focus solely on morphology without the constraint of size reduction.

Inventive Principle:

Principle #10Preliminary action

2Shape

If weak grinding energy is applied to maintain spherical shape, then particle shape is improved, but grinding time increases and productivity decreases

Engineering Contradiction:

Improveparticle shapeVSAvoidgrinding efficiency

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The grinding process is divided into two distinct stages: a first grinding step using strong grinding energy to achieve fine particle size, and a second grinding step using weak grinding energy to restore spherical shape. This segmentation allows each stage to optimize for its specific purpose without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second grinding step applies only the minimal necessary weak grinding energy required to restore spherical shape, rather than continuously applying strong energy. This partial action achieves the shaping goal while minimizing energy consumption and time, thereby improving productivity.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If particles are ground to fine spherical form, then capacity retention is improved, but the process becomes time-consuming and inefficient

Engineering Contradiction:

Improvecapacity retentionVSAvoidgrinding time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The grinding process is divided into two distinct stages: a first grinding step using strong grinding energy to achieve fine particle size, and a second grinding step using weak grinding energy to restore spherical shape. This segmentation allows each stage to optimize for its specific purpose without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first grinding step performs the preliminary action of reducing particle size to the desired fineness level before the second grinding step adjusts the shape. By preparing the particles with the correct size first, the subsequent shaping step can focus solely on morphology without the constraint of size reduction.

Inventive Principle:

Principle #10Preliminary action

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 method efficiently produces sulfide solid electrolyte particles in fine spherical form with a small surface area, improving capacity retention and uniformity, particularly suitable for solid-state batteries with alloy-based anode active materials.

Implementation Method 1

grinding the sulfide solid electrolyte material by mechanical milling to obtain particles in flattened form

Methodology Applied

Scientific EffectMechanical milling: Abrasion

Implementation Method 2

A (J) is a kinetic energy (1/2(mv2)) per grinding medium used in the first grinding step, and B (J) is a kinetic energy (1/2(mv2)) per grinding medium used in the second grinding step

Methodology Applied

Scientific EffectKinetic energy transfer: Impact Force

Data Source

PatentUS11108081B2Method for producing sulfide solid electrolyte particles

Publication Date: 2021.08.31 TOYOTA JIDOSHA KK

AI summary

A method for efficiently producing sulfide solid electrolyte particles which are particles in spherical form and which have a small particle diameter. The method comprises: preparing a sulfide solid electrolyte material, grinding the sulfide solid electrolyte material by mechanical milling to obtain particles in flattened form (a first grinding step), and grinding the particles in flattened form by mechanical milling to obtain sulfide solid electrolyte particles in spherical form (a second grinding step), wherein a relationship A (J)>B (J) is satisfied, where A (J) is a kinetic energy (½(mv2)) per grinding medium used in the first grinding step, and B (J) is a kinetic energy (½(mv2)) per grinding medium used in the second grinding step.