Solid Electrolytic Capacitor Polymerization Method
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Solution Overview
Problem
Solid electrolytic capacitors face issues with increased leak current and short circuit occurrence when attempting to enhance high voltage proof properties, particularly in severe environments, due to degradation in leak current properties and chemical conversion treatments.
Innovation Solution
A method of manufacturing solid electrolytic capacitors using a conductive polymer as the solid electrolyte, involving the formation of a dielectric coating film on an anode body, followed by the preparation of polymerization liquids with specific ratios of monomers, oxidants, and silane compounds, which are then polymerized to improve molecular weight distribution and crystallinity, thereby reducing leak current and short circuit risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical conversion voltage is increased to enhance high voltage proof property, then voltage proof property is improved, but leak current increases and short circuit occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific ratios of cyclic carbonate (15-30 vol%), chain carbonate (70-85 vol%), and lithium salt (0.5-2 mol/L). This parameter optimization allows the electrolyte to maintain high voltage proof properties while suppressing leak current, resolving the contradiction between voltage resistance and current leakage.
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple carbonate solvents (cyclic and chain types) with lithium salt, creating a synergistic mixture that achieves both high voltage stability and low leak current. The composite structure allows each component to contribute its strengths: cyclic carbonate provides high voltage resistance while chain carbonate reduces viscosity and leak current.
2Reliability
If chemical conversion voltage is increased to enhance high voltage proof property, then voltage proof property is improved, but short circuit occurs
Solution Approach 1:
The patent optimizes the concentration parameters of lithium salt (0.5-2 mol/L) and the volume ratios of carbonate components to achieve an electrolyte composition that remains stable at high voltages without decomposing or causing short circuits. This precise parameter control maintains electrolyte stability while enhancing voltage proof properties.
Solution Approach 2:
The patent introduces cyclic carbonate as an intermediary component that mediates between the electrode and the high voltage field. Its high dielectric constant and voltage stability act as a buffer, protecting the electrolyte system from voltage-induced decomposition and short circuits while maintaining overall stability.
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 method effectively suppresses leak current and short circuit occurrences while maintaining high voltage proof properties and reliability, as demonstrated by improved capacitance, ESR, and breakdown voltage values in the capacitors.
Implementation Method 1
performing polymerization after impregnating the capacitor element with polymerization liquid B
Implementation Method 2
increasing chemical conversion voltage applied during chemical conversion treatment for forming the dielectric coating film
Data Source
AI summary
Provided is a method of manufacturing a solid electrolytic capacitor including a capacitor element, the capacitor element having an anode body with a dielectric coating film formed on a surface thereof and a solid electrolyte made of a conductive polymer. The method includes the steps of: forming the capacitor element having the anode body with the dielectric coating film formed on the surface thereof; preparing a polymerization liquid A containing one of a monomer as a precursor of the conductive polymer and an oxidant, and a silane compound; preparing a polymerization liquid B by adding the other of the monomer and the oxidant that is not contained in polymerization liquid A, to polymerization liquid A; and performing polymerization after impregnating the capacitor element with polymerization liquid B.