Wet Electrolytic Capacitor Thin Powder Anodes Low ESR
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Solution Overview
Problem
Conventional wet electrolytic capacitors face challenges with high equivalent series resistance (ESR) and sensitivity to frequency due to limited surface area and size constraints, making them less suitable for applications requiring high volumetric efficiency.
Innovation Solution
A wet electrolytic capacitor design featuring a plurality of thin anodes with a thickness of 1500 micrometers or less, formed from a powder composition of valve metals, and a cathode with a high surface area, along with a working electrolyte, to minimize ESR and maximize capacitance while maintaining compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If porous sintered bodies (slugs) are used to increase surface area, then capacitance increases, but ESR increases and frequency sensitivity increases
Solution Approach 1:
The patent employs a porous anode structure formed from valve metal powder that provides high internal surface area for increased capacitance while maintaining low ESR and frequency sensitivity through controlled porosity and particle arrangement
Solution Approach 2:
The anode is constructed as a composite material combining valve metal powder particles with a binder, creating a structure that optimizes both electrical properties (low ESR) and surface area for high capacitance
2Quantity of substance
If anode slugs are used to provide high surface area, then capacitance increases, but device size increases reducing volumetric efficiency
Solution Approach 1:
The porous anode structure provides high surface area within a compact volume, achieving high capacitance without proportionally increasing device size, thus maintaining high volumetric efficiency
Solution Approach 2:
The invention transitions from dense solid anode structures to porous three-dimensional structures, utilizing internal porosity to increase effective surface area without increasing external dimensions
3Quantity of substance
If metallic foil surface is etched to increase area, then capacitance increases, but surface area is still limited
Solution Approach 1:
Instead of surface etching, the patent uses inherently porous valve metal powder that provides high surface area through its three-dimensional pore structure, eliminating the need for complex etching processes
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 design achieves excellent electrical properties with reduced ESR and enhanced capacitance, suitable for applications needing high volumetric efficiency and frequency response.
Implementation Method 1
a working electrolyte disposed in electrical contact with the cathode and anodes
Implementation Method 2
the electrostatic capacitance of the capacitor is proportional to its electrode area
Data Source
AI summary
A wet electrolytic capacitor that includes a plurality of anodes, cathode, and working electrolyte that is disposed in electrical contact with the anodes and current collector is provided. Any number of anodes may generally be employed, such as from 2 to 40, in some embodiments from 3 to 30, and in some embodiments, from 4 to 20. The anodes are thin and typically have a thickness of about 1500 micrometers or less, in some embodiments about 1000 micrometers or less, and in some embodiments, from about 50 to about 500 micrometers. By employing a plurality of anodes that are relatively thin in nature, the resulting wet electrolytic capacitor is able to achieve excellent electrical properties. For example, the equivalent series resistance (“ESR”)—the extent that the capacitor acts like a resistor when charging and discharging in an electronic circuit—may be less than about 1500 milliohms, in some embodiments less than about 1000 milliohms, and in some embodiments, less than about 500 milliohms, measured with a 2-volt bias and 1-volt signal at a frequency of 1000 Hz.