Aluminum Electroplating Solution for High-Purity Foil Production

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Solution Overview

Problem

Current methods for producing aluminum foil by electrolysis face challenges such as high chlorine concentration in plating solutions leading to equipment corrosion, low film formation rates, and difficulty in handling due to high melting point solvents, making it hard to achieve high-ductility and high-purity aluminum foils at a high film formation rate.

Innovation Solution

A plating solution for aluminum electroplating is developed with specific blending proportions of dialkyl sulfone, aluminum halide, and a nitrogen-containing compound, ensuring a low freezing point, allowing for fluidity at 25°C and high film formation efficiency, without the need for toxic organic solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plating solution with high chlorine concentration is used for aluminum electroplating, then aluminum foil can be produced by electrolysis, but equipment corrosion occurs due to hydrogen chloride gas generation

Engineering Contradiction:
Improvealuminum foil productionVSAvoidequipment corrosion
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the plating solution by replacing traditional high-chlorine electrolytes with a novel system containing lithium halide (0.5-2.0 mol/L), hydrogen halide salt of amine (0.1-1.0 mol/L), and cyclic carbonate (20-80 vol%). This parameter change eliminates hydrogen chloride gas generation while maintaining effective aluminum deposition, thus preventing equipment corrosion.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If rolling method is used to produce thin aluminum foil, then current collector thickness can be reduced, but further thickness reduction is difficult on industrial scale

Engineering Contradiction:
Improvefoil thicknessVSAvoidindustrial production capability
Core Design Contradiction:
Length of moving objectVSProductivity

Solution Approach 1:

The patent replaces the mechanical rolling process with an electrochemical deposition process. By using electrolysis to deposit aluminum onto a substrate, the method achieves precise thickness control down to micrometer and sub-micrometer levels without the physical limitations of rolling mills, thereby enabling industrial-scale production of ultra-thin foils.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If traditional plating solutions are used for aluminum electroplating, then aluminum foil production is possible, but film formation rate is low and electricity consumption is high

Engineering Contradiction:
Improvefilm formation rateVSAvoidelectricity consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes multiple parameters of the plating solution simultaneously: lithium halide concentration (0.5-2.0 mol/L), hydrogen halide salt of amine (0.1-1.0 mol/L), cyclic carbonate (20-80 vol%). This optimized parameter combination enhances aluminum ion conductivity and deposition efficiency, achieving high film formation rates with reduced electricity consumption.

Inventive Principle:
Principle #35Parameter changes

4Temperature

If plating solution freezing point is not lowered, then solution stability is maintained, but electroplating treatment cannot be performed at 25°C due to solidification

Engineering Contradiction:
Improveoperating temperatureVSAvoidsolution fluidity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent changes the physical parameters of the plating solution by selecting cyclic carbonate solvents (ethylene carbonate, propylene carbonate, butylene carbonate) which inherently possess low freezing points. The combination of these solvents with lithium halide and hydrogen halide salt of amine creates a fluid solution at 25°C, enabling electroplating treatment at ambient temperature without solution solidification.

Inventive Principle:
Principle #35Parameter changes

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 solution enables the production of high-ductility, high-purity aluminum foils with improved film formation rates and reduced electricity usage, facilitating the miniaturization of electrical storage devices and reducing environmental hazards.

Implementation Method 1

a method for aluminum electroplating comprising preparing a plating solution for aluminum electroplating

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

an aluminum film is formed on a surface of a substrate by electrolysis

Methodology Applied
Scientific EffectElectrodeposition: Electrodeposition

Implementation Method 3

the blending proportions of the dialkyl sulfone, the aluminum halide, and the nitrogen-containing compound in a preparation of a plating solution are such that per 10 mol of the dialkyl sulfone, the aluminum halide is 3.5 + n to 4.2 + n mol, and the nitrogen-containing compound is n mol (wherein n is 0.001 to 2.0 mol), thereby providing the plating solution with a freezing point of 25°C or less

Methodology Applied
Scientific EffectFreezing point depression: Freezing

Data Source

PatentEP2821529B1Method for electrical aluminum plating and method for producing aluminum foil
Publication Date: 2019.02.13 PROTERIAL LTD
  • EP2821529B1 patent drawingFigure 1~2
  • EP2821529B1 patent drawing

AI summary

An object of the present invention is to provide a method for preparing a plating solution for aluminum electroplating useful for the production of a high-ductility, high-purity aluminum foil at a high film formation rate, etc., which is an easy-to-handle plating solution that does not solidify and allows for an electroplating treatment even at 25°C. The present invention as a means for achieving the object is characterized in that in a preparation of a plating solution containing at least (1) a dialkyl sulfone, (2) an aluminum halide, and (3) a nitrogen-containing compound, the blending proportions of the dialkyl sulfone, the aluminum halide, and the nitrogen-containing compound are such that per 10 mol of the dialkyl sulfone, the aluminum halide is 3.5 + n to 4.2 + n mol, and the nitrogen-containing compound is n mol (wherein n is 0.001 to 2.0 mol). In addition, a plating solution for aluminum electroplating prepared by the method of the present invention allows for an electroplating treatment with high aluminum deposition efficiency relative to the current flow, and is thus advantageous in that electricity usage can be reduced, resulting in excellent economic efficiency.