PTFE-Conductive Binder Powder for Low-Resistance Battery Electrodes

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Solution Overview

Problem

Secondary battery electrodes using fibrillated polytetrafluoroethylene (PTFE) as a binder often exhibit high electrical resistance and uneven distribution of components, leading to reduced strength and flexibility.

Innovation Solution

A method for producing a secondary battery electrode using a non-aqueous electrolyte with a binder composed of fibrillated polytetrafluoroethylene resin and a conductive aid, such as ketjen black or carbon nanotubes, to ensure homogeneous mixing and reduce electrical resistance while maintaining strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fibrillated PTFE is used as a binder in the electrode, then the electrode can be formed with good mechanical strength, but the electrical resistance becomes high

Engineering Contradiction:
Improveelectrode strengthVSAvoidelectrical resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent combines PTFE binder and conductive aid into a single integrated powder mixture that is uniformly distributed throughout the electrode. This merging of functions allows the electrode to simultaneously achieve mechanical strength (from PTFE) and electrical conductivity (from conductive aid) without the high resistance problem associated with separate addition of these components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent emphasizes uniform distribution of the PTFE-conductive aid powder mixture throughout the electrode structure. This homogeneous distribution ensures that both mechanical strength and electrical conductivity are evenly maintained across the entire electrode, preventing localized high resistance areas while preserving overall structural integrity.

Inventive Principle:
Principle #33Homogeneity

2Ease of manufacture

If PTFE and conductive aid are mixed as separate powders, then the electrode can be manufactured, but the components become unevenly distributed leading to reduced strength and flexibility

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidcomponent distribution uniformity
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent merges PTFE and conductive aid into a pre-mixed powder composition before electrode fabrication. This combined powder mixture maintains uniform component distribution throughout the manufacturing process, ensuring consistent mechanical strength and flexibility while remaining easy to manufacture using standard electrode production techniques.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If vigorous kneading is applied to eliminate uneven distribution, then component distribution improves, but excessive PTFE fibrillation occurs reducing flexibility and strength

Engineering Contradiction:
Improvecomponent distribution uniformityVSAvoidelectrode strength and flexibility
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent achieves homogeneous component distribution through the uniform mixing of PTFE and conductive aid in powder form before electrode formation. This pre-established homogeneity eliminates the need for vigorous kneading during manufacturing, thereby preventing excessive PTFE fibrillation and preserving the electrode's flexibility and strength.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent performs the mixing and distribution of PTFE and conductive aid as a preliminary action before electrode fabrication. By establishing uniform component distribution in advance through powder mixing rather than through vigorous kneading during processing, the method prevents excessive fibrillation and maintains optimal mechanical properties.

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

The method achieves a significant reduction in electrical resistance and enhancement of electrode strength, improving the overall performance of the battery by ensuring even distribution of components and optimal fibrillation of PTFE.

Implementation Method 1

a binder composed of fibrillated polytetrafluoroethylene resin and a conductive aid, such as ketjen black or carbon nanotubes, to ensure homogeneous mixing and reduce electrical resistance

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a binder composed of fibrillated polytetrafluoroethylene resin and a conductive aid

Methodology Applied
Scientific EffectFibrillation:

Data Source

PatentUS20230378470A1Method for producing secondary battery electrode using non-aqueous electrolyte and binder for secondary battery electrode using non-aqueous electrolyte
Publication Date: 2023.11.23 DAIKIN INDUSTRIES LTD

AI summary

A method for producing a secondary battery electrode using a non-aqueous electrolyte, which includes: (1) preparing a composition for producing an electrode substantially free of a liquid medium by using a binder that is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material, and (2) preparing the composition into a sheet by applying shear stress to the composition in solvent content of 10% mass or less relative to the composition. Also disclosed is a binder for a secondary battery electrode using a non-aqueous electrolyte, that is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid in a proportion of 90:10 to 65:35 in terms of weight ratio and which is free of an electrode active material.