Aluminum Electrode Hydration Control for Capacitor Leakage Current
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Solution Overview
Problem
The existing methods for producing aluminum electrolytic capacitors face challenges in reducing leakage current due to defects in the hydrated film generated during the pure water boiling process, which cannot be adequately addressed by existing techniques, leading to increased leakage current even with additional steps.
Innovation Solution
The method involves using a hydration treatment liquid with a hydration inhibiting agent, such as organic or inorganic compounds, to control the hydration reaction rate, ensuring the thickness ratio of the hydrated film from the surface to the deep part satisfies 0.6 ≤ t2 / t1 ≤ 1, thereby reducing clogging and gas breakage during chemical formation, and employing a two-step chemical formation process with organic and inorganic acids to improve electrostatic capacitance and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure water boiling is performed before chemical formation, then electrostatic capacitance is improved and power consumption is reduced, but leakage current increases due to defects in the hydrated film
Solution Approach 1:
The patent changes the parameters of the hydration treatment by introducing a hydration inhibiting agent into the boiling water, adjusting the chemical composition to control the hydration reaction rate and prevent excessive hydration that causes defects
Solution Approach 2:
The hydration inhibiting agent acts as an intermediary substance that mediates between the aluminum electrode and water, controlling the hydration reaction to form a defective-free hydrated film while maintaining the beneficial effects of pure water boiling
2Stability of the object's composition
If pure water boiling is performed, then the hydration reaction is strong and forms a hydrated film, but the hydrated film becomes porous with many defects
Solution Approach 1:
The patent modifies the hydration treatment parameters by adding a hydration inhibiting agent to control the hydration reaction rate, preventing excessive hydration that leads to porous and defective film structure
Solution Approach 2:
The hydration inhibiting agent serves as a mediator that regulates the interaction between aluminum and water, enabling controlled hydration that forms a dense, defective-free film
3Reliability
If chemical formation is performed at voltage of 400 V or more, then higher electrostatic capacitance is achieved, but leakage current increases due to insufficient defect removal
Solution Approach 1:
The patent performs preliminary defect prevention by controlling the hydration treatment to form a defective-free hydrated film before chemical formation, eliminating the need for extensive depolarization treatment and enabling high voltage operation with low leakage current
Solution Approach 2:
The patent changes the hydration treatment parameters to control the hydration reaction, creating a high-quality hydrated film that can withstand high voltage chemical formation without generating excessive leakage current
4Stability of the object's composition
If strong hydration reaction occurs during pure water boiling, then bubbles are intensely generated, but the pits become clogged and hydration reaction cannot progress in deep parts
Solution Approach 1:
The patent adjusts the hydration reaction parameters by introducing a hydration inhibiting agent, reducing the reaction intensity to prevent bubble generation and pit clogging while ensuring uniform hydration throughout the electrode
Solution Approach 2:
The hydration inhibiting agent acts as a mediator that moderates the hydration reaction, preventing excessive bubbling and pit clogging while maintaining adequate hydration penetration into deep parts of the electrode
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 approach effectively reduces leakage current and improves hydration resistance while maintaining high electrostatic capacitance, even at chemical formation voltages of 400 V or more, without requiring significant changes to production processes or facilities.
Implementation Method 1
aluminum has high reactivity with water and thus the hydration reaction of the aluminum electrode with water during the pure water boiling is strong
Implementation Method 2
chemical formation treatment is carried out
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
Provided is a method for producing an electrode for an electrolytic capacitor, the method comprising: a hydration step in which an aluminum electrode is immersed in a hydration treatment solution having a temperature of 80°C or higher; and a chemical conversion step in which the aluminum electrode is subjected to chemical conversion treatment up to a formation voltage of at least 400 V. The hydration treatment solution contains a hydration inhibitor. The thickness of a hydrated film formed in the hydration step satisfies the following condition, 0.6 ≤ t2/t1 ≤ 1, wherein t1 is the average thickness of the hydrated film formed in a depth range of up to 100 µm from the surface of the aluminum electrode, and t2 is the average thickness s of the hydrated film formed in a deep portion at least 100 µm from the surface of the aluminum electrode.