Negative Active Material Ratio Tuning for Cycle and Storage Retention

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Solution Overview

Problem

Lithium batteries face challenges in simultaneously improving cycle performance and storage performance due to the trade-off between surface defects and side reactions, leading to low cycle and storage performance retention rates.

Innovation Solution

A negative active material with a controlled particle size distribution ratio (D90−D10)/D50 and defect degree (ID/IG) within the range of 6.0≤A/B≤7.2, which balances cycle and storage performance by optimizing the concentration of particles and surface defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface defects are increased to improve cycle performance, then dynamic performance and cycle capacity retention are enhanced, but side reactions during storage increase, reducing storage capacity retention and recovery rates

Engineering Contradiction:

Improvecycle performanceVSAvoidstorage capacity retention rate

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ratio of particle size distribution to defect degree within the specific range of 6.0≤A/B≤7.2. This parameter optimization balances the beneficial effects of surface defects on cycle performance with the need to minimize side reactions during storage, thereby simultaneously improving both cycle capacity retention and storage capacity retention rates

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining negative active material particles with specific size distributions and controlled surface defect densities. This composite approach allows the material to exhibit both high cycle stability (through optimized particle interactions) and low storage self-discharge (through controlled surface reactivity), resolving the contradiction between cycle performance and storage performance

Inventive Principle:

Principle #40Composite materials

2Reliability

If particle concentration is optimized to enhance intercalation and deintercalation performance, then cycle capacity retention improves, but manufacturing complexity and quality control difficulty increase

Engineering Contradiction:

Improvecycle capacity retention rateVSAvoidmanufacturing control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent simplifies manufacturing control by establishing a specific parameter range (6.0≤A/B≤7.2) that directly correlates with high cycle capacity retention. By controlling the ratio rather than independently optimizing multiple parameters, the patent reduces manufacturing complexity while maintaining high performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical processing and sorting operations with a chemically-based characterization approach using Raman spectroscopy (ID/IG ratio) and standardized particle size measurement. This substitution simplifies quality control by providing direct, rapid assessment of material properties that correlate with performance

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250006925A1Negative active material, negative electrode plate, battery, battery module, and electric device

Publication Date: 2025.01.02 HITHIUM TECH HK LTD

AI summary

Provided are a negative active material, a negative electrode plate, a battery, a battery module, and an electric device. A particle size distribution A of the negative active material is (D90−D10)/D50. a defect degree B of the negative active material is ID/IG. A ratio of the particle size distribution A of the negative active material to the defect degree B of the negative active material is 6.0≤A/B≤7.2.