Electrolytic Aluminum Foil Cathode Roughness Control
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Solution Overview
Problem
The production of thin aluminum foil for lithium ion batteries is hindered by high production costs due to the need for multiple rolling steps and challenges in peeling aluminum foil from cathode drums, where the foil is prone to breakage and has reduced strength and elongation due to surface roughness issues and the use of 1-10 phenanthroline anhydride, which makes the film hard and brittle.
Innovation Solution
A method involving the deposition of aluminum film on a cathode with specific surface roughness characteristics (arithmetic average roughness Ra of 0.10 to 0.40 μm and ten-point average roughness Rz of 0.20 to 0.70 μm) using a titanium cathode and a molten salt electrolytic solution containing 1-10 phenanthroline monohydrate, with controlled current density and electropolishing to achieve smooth and peelable aluminum foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume 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 number of rolling steps must be increased leading to higher production cost
Solution Approach 1:
The patent changes the manufacturing method from mechanical rolling to electrolytic deposition, fundamentally altering the process parameters. By controlling electrolysis conditions (current density, electrolyte composition, cathode surface roughness), thin aluminum foil of 5-10 μm can be produced directly without multiple rolling steps, reducing production cost while achieving the desired thickness
2Manufacturing precision
If 1-10 phenanthroline anhydride is added to the electrolytic solution to improve smoothness, then the surface smoothness improves, but the aluminum film becomes hard and brittle reducing strength and elongation
Solution Approach 1:
The patent changes the chemical form of the additive from anhydride to monohydrate, and adjusts the concentration to 0.01-0.5 g/L. This parameter change maintains surface smoothness while preventing the aluminum film from becoming hard and brittle, thereby preserving strength and elongation properties
Solution Approach 2:
The patent uses a composite electrolytic solution containing multiple components: molten salt, 1-10 phenanthroline monohydrate, and water. This composite formulation achieves synergistic effects where the monohydrate form provides smoothness without the harmful brittleness caused by the anhydride form
3Quantity of substance
If deep valley portions and high peak portions are present on the cathode surface, then aluminum can be deposited, but the bitten portions provide resistance causing breakage or cutting of the aluminum foil during peeling
Solution Approach 1:
The patent specifies optimal ranges for cathode surface roughness parameters (Ra: 0.05-0.50 μm, Rz: 0.10-1.00 μm). These parameter changes ensure sufficient surface area for aluminum deposition while preventing excessive peaks and valleys that would cause biting and breakage during peeling, thus maintaining foil integrity
4Volume of moving object
If aluminum foil is made thinner to increase battery capacity, then miniaturization is achieved, but the foil becomes more prone to breakage and requires multiple rolling steps
Solution Approach 1:
The patent changes from rolling to electrolytic deposition method, and optimizes parameters including current density (10-100 mA/cm²), electrolyte composition, and cathode surface roughness. These parameter changes enable production of ultra-thin foil (5-10 μm) with improved mechanical properties and resistance to breakage, achieving miniaturization without sacrificing reliability
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 enables the production of high-quality electrolytic aluminum foil with improved peelability, strength, and elongation, reducing production costs and ensuring uniformity and appearance properties.
Implementation Method 1
a method for producing electrolytic aluminum foil, comprising steps of depositing an aluminum film on a surface of a cathode in an electrolytic cell supplied with an electrolytic solution
Implementation Method 2
the cathode has surface roughness of an arithmetic average roughness (Ra) of 0.10 to 0.40 μm and a ten-point average roughness (Rz) of 0.20 to 0.70 μm
Data Source
AI summary
A method for producing high quality electrolytic aluminum foil excellent in peelability from a cathode surface is provided. A method for producing electrolytic aluminum foil according to the present disclosure is a method for producing electrolytic aluminum foil, comprising steps of depositing an aluminum film on a surface of a cathode in an electrolytic cell supplied with an electrolytic solution and comprising the cathode; and peeling the deposited aluminum film from the surface of the cathode to provide aluminum foil, wherein the cathode has surface roughness of an arithmetic average roughness (Ra) of 0.10 to 0.40 μm and a ten-point average roughness (Rz) of 0.20 to 0.70 μm.