LFP Electrode Material Nanoscale Particle Control for Low-Temperature Power

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Solution Overview

Problem

Current lithium iron phosphate (LFP) materials for lithium-ion batteries have limitations in extreme temperature environments, such as low energy storage at temperatures below 0°C, and require improvements in impedance, power during cold cranking, high rate capacity retention, and charge transfer resistance.

Innovation Solution

The synthesis of lithium iron phosphate (LFP) active material using a high-purity ammonium iron phosphate precursor, spheniscidite, with specific particle size and surface area characteristics, which forms nano-sized primary particles and secondary particles with controlled d50 size and carbon content, enhancing electrochemical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If current LFP materials are used, then synthesis is relatively simple, but energy storage at low temperatures (below 0°C) is insufficient

Engineering Contradiction:
Improveenergy storage at low temperatureVSAvoidperformance consistency across batches
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent changes the particle size parameter to nanoscale dimensions (5-50 nm diameter) and controls the morphology as spherical particles. This parameter change enables improved low-temperature energy storage while maintaining batch consistency through controlled synthesis methods that produce uniform particle characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the LFP material into very fine nanoscale primary particles (5-50 nm) that are then aggregated into secondary particles with controlled morphology. This segmentation increases the surface area to volume ratio, which improves ionic conductivity and electrochemical activity at low temperatures while maintaining manufacturing consistency.

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If LFP material with improved low temperature performance is synthesized, then capacity at low temperature increases, but impedance increases

Engineering Contradiction:
Improvecapacity at low temperatureVSAvoidimpedance
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the particle size parameter to nanoscale dimensions (5-50 nm) which fundamentally alters the impedance characteristics. The reduced particle size decreases the ionic diffusion path length and increases surface area for electrochemical reactions, thereby improving capacity at low temperature while actually reducing overall impedance despite the increased surface area.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from bulk LFP material to nanoscale particles, effectively moving to a different dimensional regime. This dimensional change enables simultaneous improvement of low-temperature capacity and reduction of impedance by creating a size regime where surface effects dominate and ionic transport is dramatically enhanced.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Power

If LFP material is optimized for power during cold cranking, then power output improves, but high rate capacity retention deteriorates

Engineering Contradiction:
Improvepower during cold crankingVSAvoidhigh rate capacity retention
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the particle size parameter to a specific nanoscale range (5-50 nm) that simultaneously enhances power output during cold cranking and maintains high rate capacity retention. The controlled nanoscale dimensions provide optimal balance between surface area for rapid discharge and internal structure for sustained capacity at high rates.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a dynamic structure where nanoscale primary particles are arranged in spherical aggregates that can adapt to different discharge rates. The nanoscale morphology enables rapid ion transport for high power applications while the spherical aggregate structure maintains structural integrity and capacity retention during high-rate cycling.

Inventive Principle:
Principle #15Dynamics

4Object-affected harmful factors

If LFP material with reduced particle size is used, then charge transfer resistance decreases, but manufacturing precision becomes more difficult to control

Engineering Contradiction:
Improvecharge transfer resistanceVSAvoidparticle size control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent establishes a specific nanoscale parameter range (5-50 nm) that achieves reduced charge transfer resistance while remaining manufacturable. This parameter range is optimized to balance the benefits of small particle size with the practical constraints of manufacturing control, ensuring consistent particle morphology and size distribution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs preliminary controlled synthesis steps that establish the nanoscale particle size and spherical morphology before final material formation. By controlling nucleation and growth conditions in advance, the method achieves precise particle size control at the nanoscale, enabling reduced charge transfer resistance with manufacturable precision.

Inventive Principle:
Principle #10Preliminary action

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 resulting LFP material exhibits improved capacity at low temperatures, reduced impedance, increased power during cold cranking, and enhanced charge transfer resistance, leading to improved battery performance across a broader range of temperatures.

Implementation Method 1

The mixture may then be dried and fired to obtain the lithium iron phosphate

Methodology Applied
Scientific EffectThermal decomposition: Decomposition (biological)

Implementation Method 2

The plate-shaped single-phase ammonium iron phosphate spheniscidite precursor is used in the synthesis of nano-sized lithium iron phosphate active primary particles

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Implementation Method 3

During charge the anode intercalates lithium ions from the cathode and during discharge releases the ions back to the cathode

Methodology Applied
Scientific EffectIon intercalation: Absorption (physical)

Implementation Method 4

Lithium-ion (Li-ion) batteries are a type of rechargeable battery which produce energy from electrochemical reactions

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Data Source

PatentEP3412631B1High power electrode materials
Publication Date: 2023.05.03 A123 SYSTEMS LLC
  • EP3412631B1 patent drawingFigure 1A~1B
  • EP3412631B1 patent drawingFigure 2A~2B
  • EP3412631B1 patent drawingFigure 3A~3B

AI summary

An LFP electrode material is provided which has improved impedance, power during cold cranking, rate capacity retention, charge transfer resistance over the current LFP based cathode materials. The electrode material comprises crystalline primary particles and secondary particles, where the primary particle is formed from a plate-shaped single-phase spheniscidite precursor and a lithium source. The LFP includes an LFP phase behavior where the LFP phase behavior includes an extended solid-solution range.