Negative Electrode Binder Polymer for Warping-Resistant Processing

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Solution Overview

Problem

Non-fluoropolymer binders containing unsaturated carboxylic acid monomers face limitations such as a narrow processing window and difficulty in meeting the requirements of high-performance active materials, leading to issues like warping and edge cracking during the electrode plate manufacturing process.

Innovation Solution

A polymer comprising structural units derived from unsaturated carboxylic acid, unsaturated cyano, and flexible monomers, with a glass transition temperature between -60°C to 0°C, improves water solubility, ion transmission, and bonding strength, reducing warping and enhancing flexibility to widen the processing window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If non-fluoropolymer binder containing unsaturated carboxylic acid monomer is used, then cost is reduced and bonding force is improved, but processing window becomes narrow and warping occurs

Engineering Contradiction:

Improvebonding forceVSAvoidprocessing window

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent uses a composite polymer binder containing three types of monomer units: unsaturated carboxylic acid units (for bonding), cyano units (for adhesion), and flexible units (for processing). This composite structure combines the advantages of different monomer types to achieve both strong bonding and wide processing window.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the polymer structure by controlling the glass transition temperature of the flexible monomer units to be between -60°C to 0°C. This parameter adjustment optimizes the polymer's flexibility and processing characteristics while maintaining bonding performance.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If non-fluoropolymer binder containing unsaturated carboxylic acid monomer is used, then cost is reduced, but water solubility and ion transmission are insufficient

Engineering Contradiction:

ImprovecostVSAvoidion transmission

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent incorporates unsaturated carboxylic acid monomer units that provide both cost-effectiveness and improved water solubility. The combination with cyano and flexible units creates a composite structure that enhances ion transmission channels while maintaining low cost.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polymer structure creates ion transmission channels through its molecular arrangement, facilitated by the hydrophilic carboxylic acid groups and the flexible segments that enable proper chain spacing for ion conduction.

Inventive Principle:

Principle #31Porous materials

3Ease of manufacture

If flexible monomer with low glass transition temperature is added, then warping is reduced and processing window is widened, but bonding strength may be compromised

Engineering Contradiction:

Improveprocessing windowVSAvoidbonding strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent creates a balanced composite where flexible monomer units (providing low Tg and flexibility) are combined with unsaturated carboxylic acid units (providing bonding) and cyano units (provid adhesion). This ensures both processability and bonding strength are maintained.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the polymer chain have different functions: flexible segments provide local flexibility to reduce warping, while carboxylic acid segments provide local bonding capability. This local differentiation of properties resolves the contradiction between flexibility and bonding.

Inventive Principle:

Principle #3Local quality

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 polymer effectively reduces warping and edge cracking, improves processing performance, and enhances cycle stability of the electrode plate, ensuring high bonding force and low rebound rates, thereby improving the overall battery performance.

Implementation Method 1

A glass transition temperature of the flexible monomer is -60°C to 0°C, and optionally -55°C to -15°C

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

The containing of the structural unit derived from the unsaturated carboxylic acid monomer in the polymer can improve the water solubility of the polymer, and provide an ion transmission channel for lithium ions

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

The containing of the structural unit derived from the unsaturated cyano monomer in the polymer can improve the bonding strength between the polymer and an active material as well as a current collector

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4682994A1Polymer, preparation method, negative electrode sheet, secondary battery, and electric device

Publication Date: 2026.01.21 CONTEMPORARY AMPEREX TECHNOLOGY CO LTD

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AI summary

The present application provides a polymer, a preparation method, a negative electrode plate, a secondary battery, and a power consuming apparatus. The polymer contains a structural unit derived from an unsaturated carboxylic acid monomer, a structural unit derived from an unsaturated cyano monomer, and a structural unit derived from a flexible monomer. The glass transition temperature of the flexible monomer is -60°C to 0°C, and optionally -55°C to -15°C. The polymer can reduce warping of the electrode plate and widen a processing window of the electrode plate.