Coated Active Material Slurry Drying for Battery Performance

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Solution Overview

Problem

Existing methods for producing active material composite powders for lithium ion batteries face challenges in achieving high processing speed and quality due to issues with granule formation, leading to increased reaction resistance and reduced productivity.

Innovation Solution

A coating solution with a surface energy of 72 mN/m or less is used, mixed with an electrode active material to form a slurry, which is then dried in an air flow to produce a coated active material with a lithium-containing oxide, utilizing a spray dryer and cyclone apparatus to enhance processing speed and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a tumbling fluidized bed coating method is used to spray coating solution onto active material, then coating coverage is improved, but large granules are formed due to weak disintegrating force, leading to increased reaction resistance and reduced processing speed

Engineering Contradiction:

Improvecoating coverageVSAvoidprocessing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The coating process is divided into two distinct stages: (1) spraying coating solution onto active material particles in a fluidized bed to achieve uniform coverage, and (2) subsequently adding a disintegrating agent to break apart formed granules. This segmentation allows each stage to optimize for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A disintegrating agent is introduced as an intermediary substance to mediate between the coating process and the final particle size control. This agent specifically targets and breaks the bonds formed during coating without affecting the coating coverage already achieved.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the spraying rate of coating solution is reduced to prevent granule formation, then granule formation is suppressed, but processing speed decreases, reducing productivity

Engineering Contradiction:

Improvegranule size controlVSAvoidprocessing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The coating is applied at a higher spraying rate to achieve rapid and uniform coverage of active material particles. The granule formation issue is then addressed in a subsequent step by adding the disintegrating agent, rather than limiting the spraying rate from the beginning.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The granule formation problem is extracted and addressed as a separate issue from the coating process. Instead of reducing spraying rate to prevent granule formation, the coating is applied first, and granule breakup is handled by introducing a disintegrating agent in a separate subsequent step.

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If ALD apparatus is used for vapor deposition coating, then coating quality is improved, but vacuum process requirement reduces processing speed

Engineering Contradiction:

Improvecoating qualityVSAvoidprocessing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The complex vacuum-based ALD mechanical system is replaced with a simpler fluidized bed coating system using atmospheric pressure operation. This substitution maintains coating quality while dramatically improving processing speed and productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach allows for both high processing speed and high processing quality, reducing reaction resistance and improving battery performance by suppressing granule formation and enhancing coverage of the electrode active material.

Implementation Method 1

a coating solution with low surface energy is used, and (2) an electrode active material and the coating solution are mixed in advance to prepare a slurry, and then the slurry is dried in an air flow

Methodology Applied

Scientific EffectSurface energy: Surface Tension

Implementation Method 2

drying the slurry in an air flow

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

utilizing a spray dryer and cyclone apparatus to enhance processing speed and quality

Methodology Applied

Scientific EffectCyclone separation: Cyclone Separation

Data Source

PatentUS20230045543A1Coated active material and method for producing the same

Publication Date: 2023.02.09 DOWA ELECTRONICS MATERIALS CO LTD

AI summary

Provided are a coated active material having excellent properties that can reduce the reaction resistance of a battery, and a method for producing a coated active material that can achieve both a high processing speed and high processing quality. The method for producing a coated active material includes: mixing an electrode active material and a coating solution containing Li and an element M and having a surface energy of 72 mN/m or less to prepare a slurry; and drying the slurry in an air flow and thereby causing a Li-containing oxide to adhere to at least a portion of the surface of the electrode active material, to obtain a coated active material, where the element M is at least one element selected from Nb, F, Fe, P, Ta, V, Ge, B, Al, Ti, Si, W, Zr, Mo, S, Cl, Br, and I.