Electrolytic Capacitor Electrolyte for High-Temperature Durability
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Solution Overview
Problem
Existing electrolytic capacitors face challenges in maintaining high heat resistance and durability when exposed to high-temperature environments, due to issues with solvent evaporation, viscosity, and swelling of the sealing body.
Innovation Solution
The use of a liquid component comprising a sugar alcohol component and a polyalkylene glycol component in electrolytic capacitors, which enhances the solubility and dissociability of the solute, reduces viscosity, and prevents swelling of the sealing body, thereby improving heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a non-aqueous solvent is used in the electrolytic solution to achieve small size and large capacitance, then the capacitance increases, but the solvent evaporates at high temperatures causing durability degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolytic solution by introducing sugar alcohol components (sorbitol, mannitol, xylitol, erythritol, or their derivatives) in combination with non-aqueous solvents. This compositional parameter change allows the solution to maintain low viscosity and high ion conductivity while achieving high boiling point and evaporation resistance, thus resolving the contradiction between capacitance performance and high-temperature durability.
Solution Approach 2:
The patent creates a composite electrolytic solution system by combining multiple components: non-aqueous solvent (cyclic carbonate chain carbonate), sugar alcohol component (providing high boiling point and evaporation resistance), and conductive salt. This composite material approach synergistically combines the high capacitance capability of non-aqueous solvents with the thermal stability of sugar alcohols, simultaneously achieving both improved capacitance and durability.
2Quantity of substance
If the electrolytic solution viscosity is reduced to improve ion mobility, then the capacitance increases, but the sealing body swells causing reliability degradation
Solution Approach 1:
The patent optimizes the viscosity parameter of the electrolytic solution by carefully selecting the molecular weight and structure of the non-aqueous solvent and adjusting the concentration ratios of electrolyte components. The sugar alcohol component concentration is controlled at 5-50 mass% to achieve the optimal balance between low viscosity (for high ion mobility and capacitance) and sufficient viscosity (to prevent sealing body swelling).
Solution Approach 2:
The patent applies different functional properties to different components of the electrolytic solution: the non-aqueous solvent provides low viscosity and high ion mobility in the bulk solution, while the sugar alcohol component provides localized structural stability and swelling resistance at the sealing body interface, achieving both high capacitance and reliability.
3Reliability
If a sugar alcohol component is added to the electrolytic solution to prevent sealing body swelling, then the reliability improves, but the viscosity increases causing capacitance degradation
Solution Approach 1:
The patent precisely controls the concentration parameter of the sugar alcohol component within 5-50 mass% to optimize the balance between reliability and capacitance. At this controlled concentration range, the sugar alcohol provides sufficient swelling resistance to the sealing body while maintaining the electrolytic solution viscosity at an acceptable level, thus achieving both improved reliability and preserved capacitance performance.
Solution Approach 2:
The patent uses a moderate amount of sugar alcohol component (5-50 mass%) rather than excessive amounts, which is sufficient to prevent sealing body swelling but not so much as to cause excessive viscosity increase. This partial action approach achieves the minimum necessary effect for reliability improvement while minimizing the negative impact on capacitance.
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 proposed solution achieves high heat resistance and durability for electrolytic capacitors, allowing them to maintain performance in high-temperature environments for extended periods without significant degradation.
Implementation Method 1
The use of a liquid component comprising a sugar alcohol component and a polyalkylene glycol component in electrolytic capacitors, which enhances the solubility and dissociability of the solute
Implementation Method 2
reduces viscosity
Implementation Method 3
prevents swelling of the sealing body
Data Source
AI summary
An electrolytic capacitor includes a capacitor element and a liquid component. The capacitor element includes an anode body that includes a dielectric layer on a surface of the anode body and a conductive polymer that covers a part of the dielectric layer. The liquid component includes a sugar alcohol component and a polyalkylene glycol component. The sugar alcohol component contains at least one selected from the group consisting of a sugar alcohol having four or more hydroxy groups and a derivative of the sugar alcohol.