Multi-notched Anode for Electrolytic Capacitor Delamination
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Solution Overview
Problem
Conventional solid electrolytic capacitors face challenges in achieving good adhesion between the carbonaceous layer and the solid electrolyte, leading to delamination and increased electrical series resistance (ESR), which affects their electrical performance.
Innovation Solution
A solid electrolytic capacitor design featuring a sintered, porous anode body with notches on its surface, a dielectric layer, a solid electrolyte containing conductive polymers, and an external coating with a carbonaceous and metal layer, where the anode geometry enhances adhesion and prevents delamination, thereby reducing ESR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polymeric outer layer is disposed between the carbonaceous layer and the graphite layer to improve adhesion, then adhesion between layers is improved, but achieving good adhesion between each layer remains difficult and delamination can still occur
Solution Approach 1:
A silane coupling agent is applied to the carbonaceous layer to serve as a chemical intermediary that enhances bonding between the carbonaceous layer and solid electrolyte. The silane coupling agent creates chemical bonds that bridge the interface between these two layers, preventing delamination and reducing ESR without requiring additional polymeric outer layers.
2Ease of manufacture
If conventional layers are applied without notches, then manufacturing is simpler, but delamination occurs and ESR increases
Solution Approach 1:
The anode body is segmented with notches that create distinct regions for layer application. These notches allow the solid electrolyte and carbonaceous layer to be applied in a controlled manner, ensuring proper penetration and adhesion while maintaining manufacturing simplicity. The notches divide the surface into regions that facilitate uniform layer distribution.
Solution Approach 2:
The anode body is made porous with notches that allow the solid electrolyte and carbonaceous layer to penetrate into the substrate. This porous structure enhances mechanical interlocking and chemical bonding between layers, preventing delamination while maintaining ease of manufacture through conventional sintering processes.
3Device complexity
If the carbonaceous layer is in direct contact with the solid electrolyte, then the structure is simpler, but resistance increases due to poor adhesion
Solution Approach 1:
The silane coupling agent serves as a chemical intermediary at the interface between the carbonaceous layer and solid electrolyte, creating strong adhesive bonds that reduce electrical resistance. This approach maintains structural simplicity by not adding extra layers,而是 enhancing the existing interface through chemical treatment.
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 capacitor exhibits improved mechanical robustness and electrical performance with reduced ESR and leakage current, maintaining excellent electrical properties even after reflow cycles.
Implementation Method 1
The sintered, porous anode body has a plurality of notches located on one or more exterior surfaces of the anode body
Implementation Method 2
a dielectric overlying the anode body
Implementation Method 3
the solid electrolyte contains a first conductive polymer layer
Data Source
AI summary
A solid electrolytic capacitor that includes an anode body, a dielectric overlying the anode body, a solid electrolyte that contains one or more conductive polymers and overlies the dielectric, and an external coating that overlies the solid electrolyte, is provided. The external coating includes at least one carbonaceous layer and at least one metal layer. In addition to the aforementioned layers, the external coating can also include at least one conductive polymer layer that can be disposed between the carbonaceous and metal layers. Among other things, such a conductive polymer layer can reduce the likelihood that the carbonaceous layer will delaminate from the solid electrolyte during use. Further, the notched geometry of the anode body itself is selected to minimize the risk of delamination of the external coating layers from the anode body. This combination of characteristics can increase the mechanical robustness of the part and improve its electrical performance.