Electrolytic Iron Foil Surface Control for Thin Battery Collectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of copper foils as current collectors in batteries faces challenges with strength reduction during manufacturing and handling due to heating, and achieving the necessary thickness and quality in iron foils is difficult, especially with rolling methods which can introduce impurities and work hardening.
Innovation Solution
An electrolytic iron foil with specific surface texture parameters, such as Sv/thickness ≤ 0.27, Sdq ≥ 0.06, and elongation ≥ 1.2%, is developed through electroplating, ensuring strength and elongation while minimizing breakage and tearing, suitable for both aqueous and nonaqueous battery applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper foil is used as current collector, then conductivity is improved, but strength is reduced during heating in manufacturing
Solution Approach 1:
The patent changes the material parameter from copper to iron, which has different thermal properties. Iron maintains its strength better at heating temperatures typical of battery manufacturing processes, thereby resolving the strength reduction issue during heating while still providing acceptable electrical conductivity for current collector applications.
2Productivity
If iron foil is manufactured by rolling to achieve thin thickness, then productivity is improved, but manufacturing precision deteriorates due to impurities and work hardening
Solution Approach 1:
The patent replaces the mechanical rolling process with an electroplating process. This substitution eliminates the mechanical compression and work hardening associated with rolling, preventing impurity engulfment and maintaining high purity while achieving the required thin thickness specifications for current collectors.
3Quantity of substance
If iron foil thickness is reduced to enhance battery capacity, then energy density is improved, but reliability deteriorates due to increased breakage and tearing
Solution Approach 1:
The patent changes the material composition from copper to iron, which fundamentally alters the mechanical properties. Iron provides superior strength and elongation characteristics that prevent breakage and tearing even at reduced thicknesses, thereby maintaining reliability while enabling thinner designs for enhanced battery capacity.
4Ease of manufacture
If electrolytic iron foil is produced with high iron content, then cost is reduced due to abundant resources, but manufacturing precision becomes difficult to control
Solution Approach 1:
The patent implements feedback control in the electroplating process by monitoring and controlling plating conditions such as current density, electrolyte composition, and temperature. This feedback mechanism enables precise control of surface texture parameters (Sv, Sdq) while maintaining high iron content, thereby achieving both cost-effectiveness and manufacturing precision.
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 electrolytic iron foil effectively prevents breakage and tearing during handling and maintains strength and elongation even under repetitive charging and discharging, addressing the limitations of copper foils and traditional iron foil manufacturing methods.
Implementation Method 1
manufacturing the iron foil by electroplating is considered to enable manufacture of an iron foil which has strength and elongation
Data Source
AI summary
[Object]An object of the present invention is to provide an electrolytic foil and a battery current collector capable of restraining the risk of breakage and tearing during manufacturing due to reduction in film thickness and further exhibiting sufficient strength and elongation during repetitive charging and discharging of a secondary battery.Solving MeansAn electrolytic iron foil in which the electrolytic iron foil is less than 20 μm in thickness, the electrolytic iron foil has a first surface and a second surface, and a value obtained by dividing a three-dimensional surface texture parameter Sv by the thickness is equal to or less than 0.27 in both the first surface and the second surface.