Copolymer Binder Composition for Flake-Resistant Li-Ion Electrodes

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Solution Overview

Problem

Existing binders in lithium-ion batteries are rigid, fragile, and poorly resistant to electrolytic solutions, leading to detachment and flaking of electrode plates, which affects the battery's bonding performance and cycle stability.

Innovation Solution

A copolymer-containing binder with a propylene monomer and a second monomer, such as ethylene or butadiene, is developed, with controlled crystallinity and molar ratios to achieve a softening point of 70-90°C and high bonding force, resistant to electrolytic solutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If existing rigid binders are used, then structural strength is maintained, but bonding performance deteriorates and electrode plate detachment occurs

Engineering Contradiction:
Improvebonding forceVSAvoidbonding performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by using copolymerization of propylene monomer (30-95 mol%) with second monomers (5-70 mol%), controlling crystallinity (10-40%), and adjusting softening point (70-90°C) to achieve optimal bonding performance while maintaining structural strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder system by combining copolymer with emulsifier, defoamer, and water, where the copolymer provides structural strength and the composite formulation enhances bonding performance and resistance to electrolytic solution

Inventive Principle:
Principle #40Composite materials

2Reliability

If existing binders are used, then initial bonding is achieved, but resistance to electrolytic solution deteriorates after soaking

Engineering Contradiction:
Improveresistance to electrolytic solutionVSAvoidbonding force after soaking
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent selects specific copolymer parameters including crystallinity (10-40%) and softening point (70-90°C) that provide chemical stability against electrolytic solution, preventing degradation and maintaining bonding force after prolonged soaking

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If rigid binders are applied to electrode plate, then coating is formed, but powder flaking occurs

Engineering Contradiction:
Improvecoating formationVSAvoidpowder flaking
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent adjusts the binder's softening point (70-90°C) and crystallinity (10-40%) to achieve optimal adhesion properties that prevent powder flaking during electrode plate manufacturing processes such as hot calendering and winding

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240010769A1Copolymer-containing binder and electrochemical device containing same
Publication Date: 2024.01.11 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A copolymer-containing binder and an electrochemical device containing the binder. The copolymer includes a polymer formed by copolymerizing a first monomer and a second monomer. The first monomer is a propylene monomer. A crystallinity of the copolymer is 10% to 40%. A molar percent of an amount of the first monomer in a total amount of all monomers in the copolymer is 30 mol % to 95 mol %. A molar percent of an amount of the second monomer in a total amount of all monomers in the copolymer is 5 mol % to 70 mol %. An electrode plate containing the binder according to this application is more resistant to powder flaking after being hot-calendered or wound, and is of higher quality. In addition, the binder is highly resistant to an electrolytic solution, thereby improving performance of the electrochemical device.