Polymeric Outer Layer Edge Coverage in Electrolytic Capacitors
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Solution Overview
Problem
Existing processes for producing solid electrolytic capacitors with low equivalent series resistance (ESR) and high thermal stability face challenges in achieving reliable edge and corner coverage with polymeric outer layers, often resulting in inhomogeneous layers and increased residual current due to the use of additives like solid particles, which can make the outer layer brittle.
Innovation Solution
Applying a crosslinker comprising diamine, triamine, oligoamine, or polymeric amine derivatives to the capacitor body before applying a conjugated polymer solution or dispersion, which forms a polyvalent cation, enhances edge and corner coverage without the need for additional particles, thereby improving the homogeneity and stability of the polymeric outer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid particles are added to improve edge and corner coverage, then coverage reliability is improved, but the outer layer becomes brittle and residual current increases
Solution Approach 1:
The patent removes solid particles from the polymeric outer layer formulation. Instead of adding particles to improve edge and corner coverage, the invention uses a pure polymeric composition that achieves reliable coverage through the polymer's inherent properties and application process, eliminating the brittleness and residual current issues caused by particle additives.
Solution Approach 2:
The patent modifies the chemical composition parameters of the polymeric outer layer by selecting specific conjugated polymers and their derivatives that provide both good edge and corner coverage and mechanical flexibility. The formulation parameters (polymer type, molecular weight, processing conditions) are optimized to achieve reliable coverage without requiring brittle particle additives.
2Reliability
If polymeric outer layer is applied to reduce residual current, then electrical stability is improved, but thermal stability during soldering and operation may be compromised
Solution Approach 1:
The patent employs composite material strategies by selecting conjugated polymers with specific thermal and electrical properties. The polymeric outer layer is formulated as a composite system where the conjugated polymer structure provides both low residual current and high thermal stability, capable of withstanding soldering temperatures (approx. 260°C) and elevated operating temperatures (automotive sector requirements).
Solution Approach 2:
The patent optimizes the thermal and electrical parameters of the polymeric outer layer by selecting conjugated polymers with appropriate glass transition temperatures, decomposition temperatures, and electrical conductivity. The formulation parameters are adjusted to ensure the layer maintains its protective function across the full temperature range from room temperature to soldering and operating conditions.
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 process results in solid electrolytic capacitors with improved edge and corner coverage, reduced residual current, and enhanced thermal stability, maintaining low equivalent series resistance while preventing brittleness in the polymeric outer layer.
Implementation Method 1
Applying a crosslinker comprising diamine, triamine, oligoamine, or polymeric amine derivatives to the capacitor body before applying a conjugated polymer solution or dispersion, which forms a polyvalent cation
Implementation Method 2
a polymeric outer layer is formed by at least partly removing the solvent or dispersant d)
Data Source
AI summary
The invention relates to a process for producing electrolytic capacitors with low equivalent series resistance, low residual current and high thermal stability, which consist of a solid electrolyte and an outer layer comprising conjugated polymers, to electrolytic capacitors produced by this process and to the use of such electrolylic capacitors.