Positive Electrode Active Material Hardness Mix for Adhesion and Density

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Solution Overview

Problem

The initial output and packing density of energy storage devices using lithium transition metal compounds with a polyanion structure as positive electrode active material particles are compromised due to low adhesion between the positive electrode base material and the active material particles, leading to deformation and difficulty in embedding the particles effectively.

Innovation Solution

Incorporating first active material particles with a destructive test force of 5.0 mN or more and second active material particles with a destructive test force of 4.2 mN or less, where the first particles have higher hardness and the second particles are softer, allowing for better adhesion and packing density, respectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If positive electrode active material particles containing a lithium transition metal compound having a polyanion structure are used, then the energy storage device can be constructed with known materials, but the initial output is decreased due to low adhesion between the positive electrode base material and the active material particles

Engineering Contradiction:

Improveadhesion between positive electrode base material and active material particlesVSAvoidinitial output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The invention changes the physical parameter of particle hardness by classifying active material particles into two groups: first particles with hardness of 5.0 mN or more, and second particles with hardness of 4.2 mN or less. This parameter change enables different particles to fulfill different functional requirements - harder particles for adhesion and softer particles for packing density

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by assigning different hardness characteristics to different particle populations within the same electrode system. The first particles with higher hardness are specifically suited for positions requiring strong adhesion to the base material, while second particles with lower hardness are suitable for filling interstitial spaces, creating localized functional optimization throughout the electrode structure

Inventive Principle:

Principle #3Local quality

2Reliability

If positive electrode active material particles are used to increase adhesion, then initial output may improve, but the packing density (electrode density) of the positive electrode active material particles is compromised

Engineering Contradiction:

ImproveadhesionVSAvoidpacking density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention segments the active material particles into two distinct populations based on hardness characteristics. First particles with hardness of 5.0 mN or more provide structural integrity and adhesion, while second particles with hardness of 4.2 mN or less efficiently fill void spaces. This segmentation allows each particle type to optimize for its specific function without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite particle system combining two types of active material particles with different hardness properties. This composite approach leverages the complementary strengths of harder particles (adhesion) and softer particles (packability), achieving both high adhesion and high packing density simultaneously

Inventive Principle:

Principle #40Composite materials

3Power

If harder particles are used to improve adhesion, then initial output increases, but softer particles are needed to fill voids effectively for high electrode density

Engineering Contradiction:

Improveinitial outputVSAvoidvoid volume in electrode

Core Design Contradiction:

PowerVSVolume of stationary object

Solution Approach 1:

The invention utilizes parameter changes in particle hardness to resolve the contradiction between adhesion and void filling. By establishing two distinct hardness thresholds (5.0 mN for first particles, 4.2 mN for second particles), the system enables harder particles to maintain structural integrity for adhesion while softer particles deform to eliminate void spaces, achieving both high power output and high electrode density

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4693497A1Positive electrode active material particles, positive electrode active material mixture, positive electrode for power storage element, power storage element, and power storage device

Publication Date: 2026.02.11 GS YUASA INT LTD

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AI summary

Positive electrode active material particles according to one aspect of the present invention include: first active material particles and second active material particles, in which the first active material particles and the second active material particles each contain a lithium transition metal compound having a polyanion structure, and a destructive test force of the first active material particles is 5.0 mN or more, and a destructive test force of the second active material particles is 4.2 mN or less.