Silane-Bonded Solid Electrolytic Capacitor for Low Leakage Stability
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Solution Overview
Problem
Conventional solid electrolytic capacitors using in situ polymerized polymers exhibit high leakage current and capacitance degradation at high temperatures and voltages, limiting their performance.
Innovation Solution
A capacitor assembly is designed with a porous anode body, a dielectric layer of valve metal oxide, and a solid electrolyte comprising a conductive polymer and hydroxy-functional polymer, bonded by an organofunctional silane compound to enhance interfacial adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a liquid electrolyte is used in the solid electrolytic capacitor, then the capacitor can be manufactured with conventional liquid electrolyte processes, but the capacitor occupies more space and has lower reliability due to leakage risks
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using a solid electrolyte that maintains the advantages of liquid electrolytes (ease of manufacture) while eliminating the disadvantages (leakage, space occupation). The solid electrolyte is formed by drying the liquid electrolyte-containing porous layer, transforming it from a liquid-filled structure to a solidified structure that retains porosity for ion conduction.
2Reliability
If a solid electrolyte is used in the capacitor, then the capacitor occupies less space and has higher reliability, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the porous layer with liquid electrolyte first using conventional manufacturing processes, then subsequently drying it to form the solid electrolyte. This two-step approach allows the use of standard liquid electrolyte filling techniques followed by a simple drying process, avoiding the need for complex solid electrolyte deposition equipment from the outset.
Solution Approach 2:
The patent uses the liquid electrolyte as an intermediary substance that is temporarily present during manufacturing and then transformed into the solid electrolyte. The liquid electrolyte serves as a precursor that fills the porous structure easily, and its subsequent drying converts it to the desired solid state, bridging the gap between conventional manufacturing and solid electrolyte benefits.
3Ease of operation
If the external terminals are exposed on the surface of the capacitor, then the connection is simple and direct, but the terminals are susceptible to external impacts and environmental damage
Solution Approach 1:
The patent applies the nesting principle by placing the external terminals inside the sealing structure of the capacitor body. The terminals are nested within the sealed case, protected from external environment while maintaining electrical connection functionality. This internal nesting provides mechanical protection and environmental sealing while preserving ease of connection.
Solution Approach 2:
The patent introduces the sealing structure as an intermediary between the external terminals and the external environment. This sealing layer acts as a protective mediator that shields the terminals from moisture, oxidation, and physical damage while allowing electrical signals to pass through, thus protecting the terminals without compromising their connection function.
4Productivity
If the capacitor uses a conventional structure without porous layer drying, then the manufacturing process is simpler and faster, but the capacitor has higher equivalent series resistance and lower reliability
Solution Approach 1:
The patent changes the moisture content parameter of the electrolyte layer from high (liquid-filled) to low (dried solid) to transform the electrolyte properties. This drying process reduces the equivalent series resistance by creating a solid electrolyte with optimized ion conduction pathways, while the process itself is designed to be quick and integrated into the manufacturing flow to maintain productivity.
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 capacitor assembly maintains high capacitance stability and low leakage current under high temperatures and voltages, with wet-to-dry capacitance percentage exceeding 50% and leakage current below 50 microamps, even after exposure to 105°C and 125°C for extended periods.
Implementation Method 1
the solid electrolyte has adsorption and desorption properties, the solid electrolytic capacitor assembly can maintain a low equivalent series resistance even when exposed to changes in temperature and humidity
Data Source
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AI summary
A capacitor assembly that is capable of exhibiting good electrical properties even under a variety of conditions is provided. More particularly, the capacitor assembly includes a capacitor element, which comprises a porous anode body that contains a valve metal compound, a dielectric that overlies the anode body and includes an oxide of the valve metal compound, and a solid electrolyte that overlies the dielectric. The solid electrolyte includes a conductive polymer and a hydroxy-functional polymer. Further, the capacitor element comprises an organofunctional silane compound that is bonded to the oxide of the dielectric and is capable of bonding to the hydroxy-functional polymer.