Crosslinked Polyimide Electrode Plate for Low-Resistance Li Batteries

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Solution Overview

Problem

Existing rechargeable lithium batteries face challenges in achieving high adhesive strength between active materials and current collectors while minimizing the use of fluorine-containing binders to comply with environmental regulations, which affects battery resistance and lifespan.

Innovation Solution

Employing a fluorine-free polyimide-based binder crosslinked with diamine, amino alcohol, or dialcohol compounds to enhance adhesive strength and increase active and conductive material content, thereby reducing resistance and improving battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If PVDF binders are used to provide strong oxidation resistance and high adhesive strength, then adhesive strength is improved, but fluorine content increases which violates environmental regulations

Engineering Contradiction:

Improveadhesive strengthVSAvoidfluorine content

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent removes fluorine-containing PVDF binders from the electrode composition and replaces them with fluorine-free alternatives such as polyacrylic acid, polyacrylamide, carboxymethyl cellulose, or starch binders. This extraction of the harmful fluorine component while maintaining binding functionality resolves the contradiction between adhesive strength and environmental compliance.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters of the binder from fluorine-containing PVDF to fluorine-free polymers and carbohydrates. By adjusting binder composition, molecular weight, and crosslinking degree, the patent achieves high adhesive strength without fluorine, thereby resolving the contradiction between strength and environmental harm.

Inventive Principle:

Principle #35Parameter changes

2Strength

If binder content is increased to improve adhesive strength, then adhesive strength is improved, but active material and conductive material content decrease, increasing resistance

Engineering Contradiction:

Improveadhesive strengthVSAvoidresistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent replaces physical mechanical adhesion through conventional binders with chemical adhesion through crosslinked binder networks. The crosslinking creates strong chemical bonds between active material particles and current collector, achieving high adhesive strength with minimal binder content (0.1-5 wt%), thereby reducing resistance caused by excessive binder.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a composite binder system combining multiple fluorine-free polymers and carbohydrates with crosslinking agents. This composite approach synergistically enhances adhesive strength while maintaining low binder content, allowing maximum active material loading and minimizing resistance.

Inventive Principle:

Principle #40Composite materials

3Strength

If conventional binders are used to ensure adequate adhesion, then adhesive strength is maintained, but rate capability and lifespan are limited due to higher resistance

Engineering Contradiction:

Improveadhesive strengthVSAvoidlifespan

Core Design Contradiction:

StrengthVSDuration of action of moving object

Solution Approach 1:

The patent replaces conventional mechanical adhesion with chemical crosslinking bonds that create a robust, stable network structure. This crosslinked structure maintains adhesive strength during battery cycling and operation, reducing degradation and extending lifespan while enabling better rate capability through reduced resistance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent optimizes binder molecular weight, crosslinking density, and composition ratios to achieve optimal performance. By adjusting these parameters, the patent creates a binder system that provides both high adhesive strength and excellent electrochemical stability, improving rate capability and lifespan simultaneously.

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

The solution results in rechargeable lithium batteries with improved adhesive strength, reduced resistance, and extended lifespan, while being environmentally friendly by eliminating fluorine-containing binders.

Implementation Method 1

a crosslinked product of a binder and a crosslinking agent, the binder includes a polyimide based binder, and the crosslinking agent includes at least one of a diamine based compound, an amino alcohol based compound, or a dialcohol based compound

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentUS20250279432A1Electrode plate for rechargeable lithium battery, and rechargeable lithium battery including the same

Publication Date: 2025.09.04 SAMSUNG SDI CO LTD

AI summary

An electrode plate for rechargeable lithium batteries and a rechargeable lithium battery including the same are disclosed. The electrode plate for rechargeable lithium batteries includes a current collector and an active material layer on the current collector, wherein the active material layer includes an active material; and a crosslinked product of a binder and a crosslinking agent. The binder includes a polyimide based binder, and the crosslinking agent includes at least one of a diamine based compound, an amino alcohol based compound, and a dialcohol based compound.