Positive Electrode Mixture Sequencing for Uniform Solid-State Battery Cathodes

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Solution Overview

Problem

All-solid-state batteries face challenges in achieving uniform distribution of the positive electrode mixture, leading to increased electrical resistance, reduced ion conductivity, and non-uniform current distribution, which affects the battery's performance and lifespan.

Innovation Solution

A method involving the dry-state mixing of a positive electrode active material with a solid electrolyte, followed by the addition of an additional solid electrolyte in a wet state and a conductive agent, utilizing pre-dispersion solutions to enhance the contact interface and uniform distribution of materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If solid electrolyte and active material are mixed in wet state with binder, then mixture has good processability, but contact interface between solid electrolyte and active material is disturbed and electrical resistance increases

Engineering Contradiction:
Improveprocessability of mixtureVSAvoidelectrical resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mixing process is segmented into two distinct stages: first dry mixing of solid electrolyte and active material to establish good contact interface, then wet mixing with binder for processability. This segmentation allows each stage to optimize for its specific purpose without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dry mixing of solid electrolyte and active material is performed as a preliminary action before adding the binder in wet state. This preliminary contact interface formation ensures low electrical resistance is established before the binder is introduced.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If solid electrolyte is pulverized into microscopic particles, then mixing with slurry is improved, but ion conductivity decreases due to physical restriction

Engineering Contradiction:
Improvemixing capabilityVSAvoidion conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The solid electrolyte particles are pulverized to microscopic size to improve local mixing capability and contact with active material, while the overall structure maintains sufficient ion conductivity pathways. The local particle size reduction is compensated by the triple point formation that ensures continuous ion transport routes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The electrode mixture forms a composite structure where pulverized solid electrolyte particles, active material, and conductive agent create triple points that provide both good mixing characteristics and maintained ion conductivity through the composite architecture.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If triple point is not formed in electrode, then manufacturing is simpler, but ion conductivity and electrochemical reaction are reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidion conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The manufacturing process merges dry mixing and wet mixing steps to achieve both manufacturing feasibility and triple point formation. The sequential mixing approach combines the benefits of simple process steps with the complex beneficial structure of triple points.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The particle sizes and mixing ratios of solid electrolyte, active material, and conductive agent are optimized to enable triple point formation. By controlling these parameters, the system transitions from simple mixing to structured triple point formation that enhances ion conductivity.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If positive electrode mixture is not uniformly distributed, then coating process is faster, but electrical resistance increases and current distribution becomes non-uniform

Engineering Contradiction:
Improvecoating speedVSAvoidelectrical resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The dry mixing of solid electrolyte and active material is performed as a preliminary action to establish uniform distribution and good contact interface before coating. This preliminary uniformity ensures that even with fast coating speeds, the electrical resistance remains low and current distribution is uniform.

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 approach improves the contact interface between the solid electrolyte, active material, and conductive agent, resulting in increased ion conductivity and uniform current distribution, enhancing the battery's capacity and efficiency.

Implementation Method 1

mixing a positive electrode active material and a solid electrolyte with each other in a dry state

Methodology Applied
Scientific EffectDry mixing:

Implementation Method 2

adding an additional solid electrolyte to the mixture of step a) and performing mixing in a wet state

Methodology Applied
Scientific EffectWet mixing:

Implementation Method 3

utilizing pre-dispersion solutions to enhance the contact interface and uniform distribution of materials

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 4

adding a conductive agent and performing mixing in a wet state

Methodology Applied
Scientific EffectWet mixing with conductive agent:

Implementation Method 5

increased ion conductivity and uniform current distribution

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3910705B1Method of manufacturing a positive electrode mixture for all-solid-state batteries and positive electrode mixture for all-solid-state batteries manufactured using the same
Publication Date: 2023.11.01 LG ENERGY SOLUTION LTD
  • EP3910705B1 patent drawingFigure 1~2
  • EP3910705B1 patent drawingFigure 3
  • EP3910705B1 patent drawingFigure 4

AI summary

Disclosed are a method of manufacturing a positive electrode mixture for all-solid-state batteries and a positive electrode mixture for all-solid-state batteries manufactured using the same, and more particularly a method of manufacturing a positive electrode mixture for all-solid-state batteries including mixing a positive electrode active material and a solid electrolyte with each other in a dry state, mixing the mixture with an additional solid electrolyte in a wet state, and adding a conductive agent and performing mixing in a wet state at the time of manufacturing the positive electrode mixture for all-solid-state batteries and a positive electrode mixture for all-solid-state batteries manufactured using the same.