Polyglycerol-Modified Solid Electrolyte Capacitors
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Solution Overview
Problem
Existing solid electrolyte capacitors face challenges with high equivalent series resistance (ESR) and limited breakdown voltage, especially at elevated temperatures, which affects their reliability and suitability for high-temperature applications such as in the automobile industry.
Innovation Solution
Incorporating polyglycerol into the solid electrolyte layer of capacitors, with a specific ratio of polyglycerol to conductive polymer, enhances the breakdown voltage and heat stability, improving the capacitor's performance at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If in situ polymerization is used to produce solid electrolyte capacitors, then the process can be simplified, but the breakdown voltage remains unsatisfactorily low
Solution Approach 1:
The conductive polymer is pre-synthesized and then applied to the oxide layer in dispersion form, rather than polymerizing in situ. This preliminary preparation allows for better control of polymerization conditions and results in higher breakdown voltages while maintaining process simplicity.
Solution Approach 2:
The patent changes the state of the conductive polymer from monomeric (for in situ polymerization) to polymeric dispersion form. This parameter change enables the polymer to be applied as a pre-formed coating, achieving both ease of manufacture and high breakdown voltage.
2Device complexity
If conventional solid electrolytes are used, then the capacitor structure is simple, but the equivalent series resistance increases at elevated temperatures
Solution Approach 1:
The patent uses a composite solid electrolyte consisting of conductive polymer particles dispersed in a polyglycerol matrix. This composite structure combines the high conductivity of the polymer with the thermal stability of polyglycerol, maintaining low ESR at elevated temperatures without complicating the capacitor structure.
Solution Approach 2:
Polyglycerol serves as an intermediary medium that binds the conductive polymer particles together and to the oxide layer. This intermediary material provides thermal stability and maintains electrical conductivity at high temperatures, resolving the contradiction between structural simplicity and ESR stability.
3Reliability
If polyethylene glycol is added to polymer dispersions to increase breakdown voltage, then breakdown voltage improves, but long-term stability at high temperatures deteriorates
Solution Approach 1:
The patent replaces polyethylene glycol with polyglycerol in the solid electrolyte composition. This parameter change in the chemical structure (from ethylene glycol backbone to glycerol backbone) provides both high breakdown voltage and superior long-term thermal stability, eliminating the trade-off present with polyethylene glycol.
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 use of polyglycerol significantly increases the breakdown voltage and maintains the electronic properties of capacitors, reducing ESR and capacitance loss over time, even at temperatures up to 150°C, making them more reliable for automotive applications.
Implementation Method 1
chemical or electrochemical polymerization to obtain a layer of conductive polymer
Implementation Method 2
chemical or electrochemical polymerization to obtain a layer of conductive polymer
Implementation Method 3
a dielectric which at least partly covers a surface of the electrode material and forms an anode body... on which a uniform, dielectric layer of tantalum pentoxide has been generated by anodic oxidation
Implementation Method 4
Incorporating polyglycerol into the solid electrolyte layer of capacitors, with a specific ratio of polyglycerol to conductive polymer, enhances the breakdown voltage and heat stability
Data Source
AI summary
Capacitors comprising a dielectric at least partly covering the surface of an electrode material and forming an anode body are described. The anode body may be at least partly coated with a solid electrolyte comprising a conductive polymer. The capacitor comprises at least one polyglycerol, where the ratio of the amount of polyglycerol (Mpg) to the amount of conductive polymer (Mpolymer) in the capacitor is Mpg/Mpolymer>0.15, and the polyglycerol contains more than 50 wt. % of a mixture of tri- and tetraglycerol, based on the total weight of the polyglycerol. Processes for the production of a capacitor, an electronic circuit and use of a capacitor in a dispersion are also described.