LFP Positive Active Material Particle Mix for Low-Impedance Electrodes

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Solution Overview

Problem

Lithium iron phosphate-based positive electrode materials in lithium-ion batteries suffer from high internal resistance and poor conductivity, limiting performance improvements.

Innovation Solution

Control the volume percentage ratio of lithium iron phosphate particles with sizes greater than 5 μm to those smaller than 1 μm within a range of 0.5 to 2.8, optimizing particle distribution for enhanced compacted density and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If lithium iron phosphate particles with uniform size are used, then manufacturing process is simple, but conductivity and compacted density are poor

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidconductivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the lithium iron phosphate particles into different size ranges (first particles: 3-8 μm, second particles: 0.5-3 μm) to resolve the contradiction. This segmentation allows the electrode to benefit from both large particles (good compacted density) and small particles (good conductivity and filling ability), achieving optimal performance while maintaining a relatively simple manufacturing process through controlled particle size distribution.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different particle sizes to different functional roles within the electrode structure. Larger particles serve as the main active material providing capacity, while smaller particles fill interstices and provide conductive pathways. This local differentiation of particle sizes optimizes both conductivity and compacted density without requiring complex manufacturing processes.

Inventive Principle:

Principle #3Local quality

2Reliability

If particle size is reduced to improve conductivity, then conductivity improves, but compacted density decreases

Engineering Contradiction:

ImproveconductivityVSAvoidcompacted density

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent employs the nested doll principle by having smaller lithium iron phosphate particles (0.5-3 μm) nest into the interstices between larger particles (3-8 μm). This nested arrangement maximizes the utilization of space, maintaining high compacted density while ensuring that small particles are distributed throughout the electrode to provide continuous conductive pathways and improve overall conductivity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Volume of stationary object

If large particles are used, then compacted density improves, but internal resistance increases

Engineering Contradiction:

Improvecompacted densityVSAvoidinternal resistance

Core Design Contradiction:

Volume of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent introduces smaller lithium iron phosphate particles as an intermediary between the large particles and the electrolyte/conductive network. These intermediate-sized particles (0.5-3 μm) bridge the gap by filling spaces between large particles, creating additional conductive pathways, and reducing the overall internal resistance of the electrode while maintaining the high compacted density provided by the large particles.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12548773B2Positive active material, positive electrode plate, lithium-ion battery, and electrical device

Publication Date: 2026.02.10 HITHIUM TECH HK LTD

AI summary

Provided are a positive active material, a positive electrode plate, a lithium-ion battery, and an electric device. The positive active material includes lithium iron phosphate particles. A volume percentage of the lithium iron phosphate particles having a particle size smaller than 1 μm is x, and a volume percentage of the lithium iron phosphate particles having a particle size greater than 5 μm is z, z/x ranging from 0.5 to 2.8.