Li-Ion Electrode Binder Composition for High-Temperature Cycle Life

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Solution Overview

Problem

Nonaqueous electrolyte batteries using lithium ions face issues with output reduction and shortened lifespan due to side reactions and binder swelling in high temperature environments, such as engine rooms of vehicles.

Innovation Solution

An electrode with a binder containing a polymer monomer with a nitrogen atom, specifically acrylonitrile or imide compounds, is used, ensuring a pore size distribution where the pore specific surface area to pore median diameter ratio (S/D) is greater than or equal to 35, which enhances the electrode's ability to resist swelling and maintain performance at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a nonaqueous electrolyte battery is mounted in a high temperature environment (engine room), then the space inside the vehicle can be expanded and wirings can be simplified, but side reactions between electrode active material and electrolytic solution occur, causing output reduction and shortened lifespan

Engineering Contradiction:
Improveinstallation convenienceVSAvoidbattery lifespan
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by incorporating nitrogen-containing functional groups (such as nitrile groups from acrylonitrile or imide groups from N-substituted maleimide compounds). This compositional parameter change enhances the binder's thermal stability and resistance to side reactions, allowing the battery to maintain reliability in high temperature engine room environments while preserving installation convenience

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a nonaqueous electrolyte battery is mounted in a high temperature environment (engine room), then the space inside the vehicle can be expanded and wirings can be simplified, but binder swelling and deterioration occur, causing output reduction

Engineering Contradiction:
Improveinstallation convenienceVSAvoidbinder stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The binder's chemical composition is modified by incorporating nitrogen-containing functional groups (nitrile groups from acrylonitrile or imide groups from N-substituted maleimide compounds). This compositional change increases the binder's resistance to swelling and deterioration at high temperatures, maintaining structural stability while allowing flexible installation in the engine room

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder system combining polymers with nitrogen-containing functional groups (acrylonitrile or N-substituted maleimide compounds) with other binder components. This composite structure provides both the swelling resistance needed for high temperature stability and the adhesive properties required for electrode integrity, resolving the conflict between installation flexibility and compositional stability

Inventive Principle:
Principle #40Composite materials

3Device complexity

If conventional binders are used in high temperature environments, then the electrode structure is simple, but side reactions occur and binder swelling reduces output

Engineering Contradiction:
Improveelectrode structureVSAvoidbattery output
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The patent modifies the binder's chemical composition by incorporating nitrogen-containing functional groups (nitrile groups from acrylonitrile or imide groups from N-substituted maleimide compounds). This compositional parameter change enhances resistance to side reactions and binder swelling, maintaining high battery output performance while preserving relatively simple electrode structure without requiring complex multi-layer designs

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 electrode achieves high output and excellent high temperature durability by effectively suppressing side reactions and maintaining cycle life characteristics, even under repeated charge and discharge cycles in high temperature conditions.

Implementation Method 1

The binder includes a polymer that contains a monomer containing a nitrogen atom... effectively suppressing side reactions

Methodology Applied
Scientific EffectChemical resistance:

Implementation Method 2

In the pore size distribution of the electrode, the following formula (1) is satisfied: S/D≥35... maintaining cycle life characteristics

Methodology Applied
Scientific EffectPorosity control: Porosity

Data Source

PatentEP3540827B1Electrode, secondary battery, battery pack, and vehicle
Publication Date: 2023.08.30 KK TOSHIBA
  • EP3540827B1 patent drawingFigure 1~2
  • EP3540827B1 patent drawingFigure 3~4
  • EP3540827B1 patent drawingFigure 5

AI summary

According to one approach, an electrode is provided. The electrode includes a binder, and an active material represented by a general formula LixMyO2, where 0 ≤ x ≤ 1.33 and 0.5 ≤ y ≤ 1 are satisfied and M contains at least one element selected from the group consisting of Ni, Co, and Mn. The binder includes a polymer that contains a monomer containing a nitrogen atom. In the pore size distribution of the electrode according to mercury porosimetry, the following formula (1) is satisfied when the pore median diameter is represented by D [µm] and the pore specific surface area is represented by S [m2/g] : S/D≥35