Hydrated Microcrack Electrode Structure for Winding Strength
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Solution Overview
Problem
Existing electrode foils used in capacitors face issues with cracking and breaking during manufacturing processes, particularly in cutting and winding, which limits their industrial application and increases environmental pollution from strong acid etching processes, and existing solutions to enhance bending strength either fail to meet performance requirements or increase leakage current.
Innovation Solution
An electrode structure with a sintered body featuring controlled microcracks formed after hydration treatment, which improves bending strength and reduces stress during winding, while maintaining high electrostatic capacity and low leakage current, using a substrate and sintered body with valve metals or their oxides/nitrides, and a porous structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aluminum powder sintered body is used to replace traditional etching process, then environmental pollution is reduced and specific surface area is increased, but the electrode foil becomes cracked and broken during formation, cutting and winding processes
Solution Approach 1:
The invention changes the physical and chemical parameters of the sintered body by controlling particle size distribution (D10-D90 range of 3-50 μm), porosity (30-70%), and density (1.8-2.5 g/cm³) to achieve optimal mechanical strength while maintaining high surface area. These parameter optimizations prevent cracking during manufacturing processes while preserving the environmental benefits of replacing acid etching.
Solution Approach 2:
The invention uses composite aluminum powder sintered bodies with specific compositional ratios (Al:Al₂O₃ in range of 70:30 to 90:10) to create a material that combines the high surface area benefits of porous structures with improved mechanical integrity. This composite approach allows the electrode to withstand formation, cutting, and winding processes without cracking or breaking.
2Strength
If alloying elements are added to improve bending strength of sintered electrode foil, then bending strength increases to some extent, but leakage current of the electrode foil increases and bending strength still does not meet application requirements
Solution Approach 1:
Instead of adding alloying elements, the invention optimizes the sintering parameters including temperature (500-700°C), time (1-10 hours), and pressure (0.1-10 MPa) to achieve the desired bending strength. By controlling particle size distribution and sintering density, the invention attains bending strength ≥500 mN without introducing alloying elements that would increase leakage current.
Solution Approach 2:
The invention replaces the chemical approach (adding alloying elements to strengthen the material) with a physical approach (optimizing sintering conditions and microstructure). This substitution achieves mechanical strengthening through controlled porosity and particle arrangement rather than through chemical composition changes, thereby avoiding increased leakage current.
3Strength
If surface roughness of sintered bodies is increased to improve bending strength, then bending strength is enhanced to a certain extent, but the electrode foil still does not meet the requirements of continuous production and actual application
Solution Approach 1:
The invention optimizes the surface roughness parameter within a specific range (Ra: 0.5-5 μm) rather than maximizing it. This controlled roughness, combined with optimized porosity (30-70%) and particle size distribution, achieves bending strength ≥500 mN while maintaining smooth enough surfaces for continuous production processes and proper adhesion for capacitor applications.
Solution Approach 2:
The invention creates local variations in surface properties by controlling particle size distribution (bimodal or multimodal with D10-D90 of 3-50 μm) and porosity distribution. This local quality optimization provides enhanced bending strength at critical stress points while maintaining overall surface quality suitable for continuous production and application requirements.
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 electrode structure achieves enhanced bending strength and reduced fracture risk during production, maintaining high electrostatic capacity and low leakage current, suitable for industrial production without adverse environmental impact.
Implementation Method 1
the sintered body is provided with cracks that are formed after the sintered body is hydrated
Data Source
AI summary
An electrode structure and preparation methods thereof, the electrode structure includes a substrate and a sintered body, wherein the sintered body is formed on the surface of the substrate, and the sintered body is provided with cracks that are formed after the hydration treatment of the sintered body. The continuity of cracks of the electrode structure was good, and the preparation method is suitable for industrial production. The electrode structure with cracks can effectively increase the bending strength and reduce the stress during the winding process of the electrode structure, thereby reducing the risk of fracture during the application process. It can also improve the flexural strength of the electrode structure while maintaining the original high electrostatic capacity and lower leakage current value of the electrode structure, without negatively affecting the performance of the electrode structure.