Battery Negative Electrode Composition for Higher Peel Strength

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Graphite with low particle internal porosity has poor binding properties with other materials, leading to reduced peel strength between the negative electrode mixture layer and the current collector, which can result in contact failure and capacity deterioration when combined with a Si-containing material.

Innovation Solution

A negative electrode comprising a mixture layer with graphite particles having a particle internal porosity of ≤5% and a Si-containing material dispersed in a carbon phase, with specific mass percentages of both components, enhances the peel strength by increasing the aggregation and contact area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If graphite particles with low particle internal porosity (≤5%) are used as negative electrode active material, then battery energy density is improved, but peel strength between negative electrode mixture layer and current collector is reduced

Engineering Contradiction:

Improvebattery energy densityVSAvoidpeel strength between negative electrode mixture layer and current collector

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent uses a composite material system consisting of graphite particles (with low porosity ≤5%), Si-containing material, and binder material. This composite structure allows the graphite to provide high energy density while the Si-containing material and binder material work together to ensure adequate peel strength and adhesion to the current collector.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges: graphite particle internal porosity ≤5%, Si-containing material content ≥1 mass%, and binder material content ≥1 mass%. By controlling these parameters within specific ranges, the patent achieves both high energy density (through low porosity graphite) and sufficient peel strength (through optimized content ratios of Si-containing material and binder material).

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If graphite particles with low particle internal porosity are combined with Si-containing material in silicate phase, then battery capacity is improved, but contact failure between negative electrode mixture layer and current collector occurs

Engineering Contradiction:

Improvebattery capacityVSAvoidcontact failure between negative electrode mixture layer and current collector

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent employs a composite material system where graphite particles (≤5% porosity) are combined with Si-containing material dispersed in a carbon phase, along with binder material. This composite structure maintains battery capacity while preventing contact failure through the synergistic interaction of components.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The binder material acts as an intermediary substance that mediates between the graphite particles/Si-containing material and the current collector. It provides adhesion and prevents contact failure while allowing the low-porosity graphite and Si-containing material to maintain high battery capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If densified carbon with low particle internal porosity is used as negative electrode active material, then energy density is improved, but binding properties with other materials deteriorate

Engineering Contradiction:

Improveenergy densityVSAvoidbinding properties with other materials

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent creates a composite material system where densified graphite particles (≤5% porosity) are combined with Si-containing material and binder material. The composite structure preserves the high energy density of densified carbon while the Si-containing material and binder material provide the necessary binding properties and stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes parameter ranges: graphite particle internal porosity ≤5% for high energy density, Si-containing material content ≥1 mass%, and binder material content ≥1 mass%. These parameter controls ensure that binding properties are maintained despite using densified carbon with low porosity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12567579B2Negative electrode for secondary battery, and secondary battery

Publication Date: 2026.03.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

This negative electrode for a secondary battery includes a negative electrode mixture layer that includes: a negative electrode active material containing graphite particles and a Si-containing material; and a binder. The Si-containing material includes a Si-containing material A that includes a carbon phase and silicon particles dispersed in the carbon phase. The graphite particles include graphite particles A with 5% or less particle internal porosity, and the content of the graphite particles A is at least 10% by mass with respect to the total mass of the negative electrode active material. The content of the Si-containing material A is at least 1% by mass with respect to the total mass of the negative electrode active material.