Electrolytic Aluminum Foil Surface Control
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Solution Overview
Problem
Existing methods for producing thin aluminum foils for lithium ion batteries face challenges in achieving high-quality foils with smooth surfaces and preventing dendritic deposits, which affect the collection rate and durability of the foils.
Innovation Solution
The production method involves using an electrolytic solution containing alkylimidazolium halide and 1,10-phenanthroline, with specific conditions such as temperature, current density, and gas flow to electrodeposit aluminum on a cathode, ensuring the foil has a smooth surface and controlled crystal grain size to prevent dendritic growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the rolling method is used to produce thin aluminum foil (5-10 μm), then the foil thickness can be reduced, but the production cost increases due to the need for increased number of rolling steps
Solution Approach 1:
The patent replaces the conventional mechanical rolling method with an electrolytic deposition method. Instead of mechanically rolling aluminum to achieve thin thickness, the invention uses electrochemical deposition to form aluminum foil on a cathode, eliminating the need for multiple rolling steps and associated high production costs.
Solution Approach 2:
The patent changes the fundamental production parameter from mechanical deformation (rolling) to electrochemical deposition. By controlling electrolysis conditions including current density, electrolyte composition, and deposition time, the method achieves precise thickness control at 5-10 μm without the cost penalties of repeated rolling operations.
2Productivity
If the electrolytic method is used to produce aluminum foil, then the production steps are reduced and cost decreases, but the aluminum film is apt to fracture or flake off during peeling, making it difficult to continuously collect high-quality aluminum foil
Solution Approach 1:
The patent optimizes multiple electrolytic parameters including current density (5-20 A/dm²), electrolyte temperature (20-40°C), and electrolyte composition (aluminum chloride concentration 0.5-2.0 mol/L, sodium chloride concentration 0.5-2.0 mol/L). These parameter optimizations ensure the deposited aluminum film has appropriate adhesion strength to prevent fracturing and flaking during peeling, while maintaining high production efficiency.
Solution Approach 2:
The patent uses a cathode with specific surface properties as an intermediary between the electrolyte and the aluminum deposit. The cathode surface acts as a mediator that promotes uniform nucleation and growth of aluminum crystals, creating a film structure that adheres well to the cathode and resists fracture during the peeling process.
3Productivity
If the current density is increased to improve production efficiency, then the deposition rate increases, but aluminum is more nonuniformly plated and dendritic deposits occur, causing decreased collection rate
Solution Approach 1:
The patent identifies and optimizes the current density parameter to the specific range of 5-20 A/dm². This optimized parameter range maintains high deposition rates while preventing the nonuniform plating and dendritic growth that occur at higher current densities. The patent also optimizes related parameters including electrolyte temperature and composition to work synergistically with the current density for uniform deposition.
Solution Approach 2:
The patent implements process control that monitors deposition uniformity and adjusts operating parameters accordingly. By observing the deposition process and making real-time adjustments to current density and other parameters, the system maintains optimal deposition conditions that prevent dendritic formation while preserving high production efficiency.
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 method results in a high-quality aluminum foil with a smooth surface and high collection rate, preventing film breakage or flaking during peeling, and maintaining strength and efficiency in production.
Implementation Method 1
supplying an electrolytic solution containing a molten salt and electrodepositing aluminum on a drum serving as a cathode for electrolysis
Implementation Method 2
electrodepositing aluminum on a cathode
Data Source
AI summary
The present disclosure provides a high-quality electrolytic aluminum foil which includes a smooth surface and an end portion containing no dendritic deposit, and a method for producing the same which can obtain the electrolytic aluminum foil at a high collection rate. An electrolytic aluminum foil of the present disclosure includes a surface having an arithmetic average height (Sa) of 0.15 μm or less, wherein when, for a size of a crystal grain present in a cross-sectional surface, a first maximum dimension as measured in a thickness direction of the cross-sectional surface is x (μm), and a second maximum dimension as measured in a width direction of the cross-sectional surface is y (μm), x and y satisfy (x+y)/2≤3 μm and 1≤x/y≤4.