Carbon-Coated Lithium Iron Phosphate Slurry Cooling for Stable Carbon Content

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Solution Overview

Problem

Conventional carbon coating processes for lithium iron phosphate materials face issues with temperature fluctuations leading to oxidation and decomposition of the carbon source, affecting the solubility of lithium salts and resulting in unstable carbon content and quality.

Innovation Solution

A manufacturing method that controls slurry temperature between 25 °C to 40 °C using a liquid cooling jacket during grinding, ensuring consistent lithium solubility and preventing carbon source oxidation, followed by drying and sintering to form a carbon-coated lithium iron phosphate material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional carbon coating process is used with alkaline slurry and grinding, then carbon coating is applied to lithium iron phosphate, but temperature rise causes oxidation and decomposition of carbon source

Engineering Contradiction:
Improvecarbon content stabilityVSAvoidslurry temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies preliminary cooling action by pre-cooling the slurry to a specific temperature range (20-40°C) before adding the carbon source, and maintains this temperature during the grinding process. This preliminary temperature control prevents the carbon source from oxidizing and decomposing due to temperature rise, thereby ensuring stable carbon content in the final product.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the temperature parameter of the slurry from uncontrolled/high temperature to a controlled range of 20-40°C. This parameter change is achieved through cooling measures during the grinding process, which prevents carbon source decomposition and ensures reliable carbon coating on lithium iron phosphate particles.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional grinding process is used without temperature control, then mixing and grinding are completed, but temperature fluctuations affect lithium salt solubility and product stability

Engineering Contradiction:
Improvegrinding efficiencyVSAvoidlithium salt solubility consistency
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent implements temperature feedback control during the grinding process by monitoring the slurry temperature and adjusting cooling measures to maintain temperature within the 20-40°C range. This feedback mechanism ensures that lithium salt solubility remains consistent throughout the grinding process, preventing composition instability while maintaining grinding efficiency.

Inventive Principle:
Principle #23Feedback

3Speed

If high temperature environment is used during grinding, then grinding process proceeds faster, but carbon source oxidizes and decomposes

Engineering Contradiction:
Improvegrinding speedVSAvoidcarbon source loss
Core Design Contradiction:
SpeedVSLoss of substance

Solution Approach 1:

The patent creates a low-temperature environment (20-40°C) during the grinding process, which acts as a protective condition preventing oxidation and decomposition of the carbon source. This controlled temperature environment allows the grinding to proceed effectively while minimizing carbon source loss through oxidation.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

Guarantees optimal carbon content and enhances the stability of the carbon-coated lithium iron phosphate material by maintaining temperature consistency and avoiding decomposition, resulting in improved product quality.

Implementation Method 1

the slurry temperature is controlled by employing liquid cooling method through a cooling jacket

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a liquid flows in the cooling jacket to absorb a heat generated from the second slurry in the first chamber

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a liquid flows in the cooling jacket to absorb a heat generated from the second slurry in the first chamber

Methodology Applied
Scientific EffectHeat absorption: Heat Sink

Implementation Method 4

drying and sintering the third slurry to form the carbon-coated lithium iron phosphate material including a core layer and a coating layer coated on the core layer

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP4434938B1Manufacturing method of carbon-coated lithium iron phosphate material
Publication Date: 2025.07.02 ADVANCED LITHIUM ELECTROCHEMISTRY CO LTD
  • EP4434938B1 patent drawingFigure 1
  • EP4434938B1 patent drawingFigure 2A
  • EP4434938B1 patent drawingFigure 2B

AI summary

A manufacturing method of a carbon-coated lithium iron phosphate material is disclosed. The manufacturing method includes steps of: (a) providing a first slurry, a carbon source and a lithium source, wherein the first slurry is formed from an iron source and a phosphorus source; (b) mixing the first slurry, the carbon source and the lithium source to form a second slurry, and grinding the second slurry in a tank (1) at a first temperature to form a third slurry, wherein the first temperature is ranged from 25 °C to 40 °C; and (c) drying and sintering the third slurry to form the carbon-coated lithium iron phosphate material including a core layer and a coating layer coated on the core layer, wherein the core layer is formed from the lithium source, the iron source and the phosphorus source, and the coating layer is formed from the carbon source.