Self-Doped Electrolyte Layer for Stable ESR in Electrolytic Capacitors
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Solution Overview
Problem
Electrolytic capacitors face a challenge in maintaining low equivalent series resistance (ESR) over a long period, particularly due to dedoping of dopants in the electrolyte layer, which leads to increased ESR with time.
Innovation Solution
The use of a self-doped conductive polymer and a non-aqueous solvent in the electrolyte layer, along with a polymer dopant containing an acidic group, helps to suppress the increase in ESR over time by minimizing dedoping, and the manufacturing method involves forming a polymer layer with these components adjacent to the dielectric layer and impregnating it with a non-aqueous solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conductive polymer electrolyte layer is used, then the capacitor achieves large capacitance and low initial ESR, but the ESR increases significantly over time due to dopant dedoping
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte layer by using self-doped conductive polymers where the dopant is covalently bonded to the polymer backbone, and by selecting specific non-aqueous solvents with controlled water content (0-50 wt%), thereby stabilizing the ESR over long periods
Solution Approach 2:
The patent creates a composite electrolyte layer combining self-doped conductive polymer materials with non-aqueous solvents, forming a hybrid system that leverages the stability of covalent bonding and the beneficial properties of non-aqueous environments to prevent dedoping
2Ease of manufacture
If aqueous solvents are used in the electrolyte layer, then the conductive polymer processes easily, but the ESR increases due to water-induced dedoping
Solution Approach 1:
The patent changes the solvent parameter from aqueous to non-aqueous, controlling water content at 0-50 wt%, which prevents water-induced dedoping while maintaining manufacturability through impregnation processes
Solution Approach 2:
The non-aqueous solvent acts as an intermediary that facilitates the impregnation of the polymer layer without causing dedoping, mediating between the polymer and the environment to prevent harmful water interaction
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
This approach results in an electrolytic capacitor with a low increase ratio of ESR over a long period, maintaining initial low ESR values even at high temperatures, thereby enhancing the capacitor's long-term performance.
Implementation Method 1
a step (ii) of forming a polymer layer containing a first conductive polymer to be adjacent to the dielectric layer by an impregnation treatment
Implementation Method 2
a step (iii) of impregnating the polymer layer with a non-aqueous solvent
Data Source
AI summary
An electrolytic capacitor includes a capacitor element. The capacitor element includes an anode body and an electrolyte layer. The anode body has a dielectric layer on a surface of the anode body. The electrolyte layer is disposed to be adjacent to the dielectric layer. The electrolyte layer contains a first conductive polymer and a non-aqueous solvent. The first conductive polymer is a self-doped conductive polymer.