Aluminum Capacitor Electrode Hydration Cycles to Prevent Porous Clogging
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Solution Overview
Problem
Existing methods for producing aluminum electrolytic capacitors face challenges in increasing electrostatic capacitance without forming thick hydrated films, which leads to clogging and reduced hydration resistance and capacitance, especially at higher chemical formation voltages.
Innovation Solution
A method involving a first hydration treatment, dehydration at 150° C to 350° C, and a second hydration treatment followed by chemical formation, which reduces the formation of thick hydrated films and increases the amount of highly crystalline pseudo-boehmite, thereby enhancing electrostatic capacitance and reducing clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the boiling time is extended to increase the amount of pseudo-boehmite and improve electrostatic capacitance, then the electrostatic capacitance increases, but the hydrated film becomes too thick and clogs the porous part of the aluminum electrode
Solution Approach 1:
The patent divides the single prolonged boiling process into multiple separate hydration treatment steps with intermediate dehydration steps. This segmentation allows the hydrated film to be formed in controlled amounts multiple times rather than forming a single thick film, preventing clogging while accumulating sufficient pseudo-boehmite content for high electrostatic capacitance.
Solution Approach 2:
The patent performs preliminary dehydration treatment at 100-200°C before the final chemical formation step. This preliminary action removes excess water from the hydrated film, preventing it from becoming too thick and clogging the porous structure, while preserving the pseudo-boehmite content needed for high capacitance.
2Quantity of substance
If the boiling time is extended to increase the amount of pseudo-boehmite, then the electrostatic capacitance improves, but the hydration resistance of the chemical formation film deteriorates
Solution Approach 1:
By segmenting the hydration process into multiple steps with intermediate dehydration, the patent prevents the formation of excessively thick hydrated film that would compromise hydration resistance, while still accumulating sufficient pseudo-boehmite through repeated formation cycles to achieve high electrostatic capacitance.
Solution Approach 2:
The patent changes the temperature parameter during dehydration (100-200°C) to optimize the removal of excess water while preserving the crystalline structure of pseudo-boehmite. This parameter control ensures that pseudo-boehmite content increases for high capacitance without creating conditions that would reduce hydration resistance.
3Quantity of substance
If the boiling time is extended to increase the amount of pseudo-boehmite, then the electrostatic capacitance increases, but the thickness of the hydrated film increases causing clogging
Solution Approach 1:
The patent segments the hydration process into multiple steps with intermediate dehydration, allowing pseudo-boehmite to accumulate in a controlled manner without the hydrated film thickness increasing proportionally. Each hydration-dehydration cycle builds pseudo-boehmite content while removing excess water, decoupling the relationship between pseudo-boehmite amount and film thickness.
Solution Approach 2:
The preliminary dehydration step at 100-200°C before chemical formation removes excess water from the hydrated film, preventing thickness increase and clogging, while the pseudo-boehmite content accumulated during hydration remains intact for high electrostatic capacitance performance.
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 increases electrostatic capacitance while minimizing clogging and maintaining high hydration resistance, particularly effective at chemical formation voltages of 400 V or more, and significantly improves performance at 600 V or more.
Implementation Method 1
a dehydration step of heating the aluminum electrode in an atmosphere having a temperature of 150° C. or more and 350° C. or less after the first hydration treatment step
Implementation Method 2
the ratio of crystal water eliminated at 350° C. or more is increased. Consequently, the amount of highly crystalline pseudo-boehmite can be increased
Implementation Method 3
a first hydration treatment step of forming a hydrated film onto an aluminum electrode including a porous layer by immersing the aluminum electrode into a first hydration treatment liquid having a temperature of 80° C. or more
Implementation Method 4
forming a hydrated film onto an aluminum electrode including a porous layer by immersing the aluminum electrode into a first hydration treatment liquid
Implementation Method 5
a chemical formation step of performing chemical formation of the aluminum electrode after the second hydration treatment step
Data Source
AI summary
In production of an electrode for an aluminum electrolytic capacitor, a hydrated film is formed onto an aluminum electrode including a porous layer by immersing the aluminum electrode into a first hydration treatment liquid having a temperature of 80° C. or more in a first hydration treatment step (ST1) and thereafter the aluminum electrode is heated in an atmosphere having a temperature of 150° C. or more and 350° C. or less in a dehydration step (ST2). Subsequently, a hydrated film is formed onto the aluminum electrode by immersing the aluminum electrode into a second hydration treatment liquid having a temperature of 80° C. or more in a second hydration treatment step (ST3) and thereafter chemical formation of the aluminum electrode is performed at 400 V or more and further 600 V or more in a chemical formation step.