Solid Electrolytic Capacitor Layer Structure Against Oxygen Ingress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid electrolytic capacitors experience a decrease in electrostatic capacity due to oxygen entering the capacitor element from the outside air, which is exacerbated at high temperatures, leading to deterioration of the solid electrolyte layer.
Innovation Solution
The design incorporates a solid electrolytic capacitor element with a porous anode body, a dielectric layer, and a cathode part, featuring a first and second solid electrolyte layer where the second solid electrolyte layer has a thickness of at least 1 μm in a specific region to prevent oxygen entry, and the use of an adhesive agent and insulating resin to enhance oxygen barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the solid electrolyte layer is made thin to reduce capacitor element size, then the capacitor element becomes more compact, but oxygen enters more easily causing deterioration of electrostatic capacity
Solution Approach 1:
The solid electrolyte layer is segmented into two distinct layers: a first solid electrolyte layer with thickness of 0.01 μm or more but less than 1 μm, and a second solid electrolyte layer with thickness of 1 μm or more. This segmentation allows the first layer to provide electrostatic capacity while the second layer acts as an oxygen barrier, resolving the contradiction between compact size and reliability.
Solution Approach 2:
Different regions of the solid electrolyte structure are assigned different qualities: the first solid electrolyte layer has high conductivity for electrostatic capacity, while the second solid electrolyte layer has thick barrier properties for oxygen prevention. This local differentiation of properties allows simultaneous optimization of both compactness and reliability.
2Reliability
If the second solid electrolyte layer is made thick to prevent oxygen entry, then oxygen barrier properties improve, but the capacitor element size increases
Solution Approach 1:
The solid electrolyte layer is divided into two functional segments: a thin first layer (0.01-1 μm) for electrostatic capacity and a thick second layer (≥1 μm) for oxygen barrier properties. This segmentation enables the oxygen barrier function to be achieved without requiring the entire solid electrolyte structure to be thick, thus maintaining compact element size while improving reliability.
Solution Approach 2:
The first solid electrolyte layer serves dual functions: it provides electrostatic capacity through its conductivity while also serving as part of the overall oxygen barrier system when combined with the second layer. This multi-functionality allows the structure to achieve both compact size and superior oxygen barrier properties.
3Reliability
If the first solid electrolyte layer is made thin to increase the second layer thickness for oxygen barrier, then oxygen protection improves, but electrostatic capacity decreases
Solution Approach 1:
The solid electrolyte layer is segmented into a first layer (0.01 μm or more but less than 1 μm) optimized for electrostatic capacity and a second layer (≥1 μm) optimized for oxygen barrier properties. This segmentation ensures that the first layer maintains sufficient thickness for adequate electrostatic capacity while the second layer provides robust oxygen protection, resolving the contradiction between these two requirements.
4Reliability
If the solid electrolyte layer thickness is increased to prevent oxygen entry, then oxygen barrier properties improve, but manufacturing precision requirements increase
Solution Approach 1:
The solid electrolyte layer is segmented into two layers with clearly defined thickness ranges: the first layer (0.01-1 μm) and the second layer (≥1 μm). This segmentation simplifies manufacturing precision requirements by establishing distinct thickness specifications for each layer, making it easier to control overall thickness while ensuring adequate oxygen barrier properties through the second layer.
Data Source
AI summary
A solid electrolytic capacitor element includes an anode body including a porous part, a dielectric layer, and a cathode part. The cathode part includes a solid electrolyte layer covering the dielectric layer. The anode body includes a first anode body part on which the solid electrolyte layer is disposed and a second anode body part on which the solid electrolyte layer is not disposed. The solid electrolyte layer includes a first solid electrolyte layer disposed in the porous part and a second solid electrolyte layer disposed outside the porous part. When a length of the first anode body part in a longitudinal direction thereof is defined as a length L, a thickness of the second solid electrolyte layer in a first region is more than or equal to 1 μm. The first region is a region between boundary between the first anode body part and the second anode body part and a position located away from boundary in a length 0.05 L in the first anode body part.