Solid Electrolytic Capacitor Grooved Frames Moisture Ingress
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Solution Overview
Problem
Existing solid electrolytic capacitors face issues with moisture ingress due to the inability of their exterior bodies to fully prevent external moisture, leading to potential internal pressure increases and poor appearance during reflow mounting, as well as increased equivalent series resistance (ESR).
Innovation Solution
The design incorporates an anode and cathode frame with grooves on their surfaces adhered to the exterior body, which intersect with the extending direction of the frames, creating a detouring path for moisture and enhancing adhesiveness between the exterior body and the frames, thereby preventing moisture ingress and reducing the risk of internal pressure and ESR increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the exterior body is made to fully seal the capacitor element, then moisture prevention is improved, but internal pressure buildup during reflow mounting worsens
Solution Approach 1:
The exterior body is designed with differentiated local properties: the majority of the surface maintains high sealing quality to prevent moisture ingress, while specific localized regions (venting portions) provide controlled pressure relief. This allows the structure to simultaneously achieve both moisture prevention and pressure management without compromising either function.
Solution Approach 2:
The venting portions act as intermediary elements between the sealed interior and the external environment. These portions provide a controlled interface that allows moisture vapor to escape during reflow mounting while maintaining the overall sealing integrity of the exterior body, thus mediating between the conflicting requirements of complete sealing and pressure relief.
2Stress or pressure
If gas-venting micro-pores are provided on the exterior body, then internal pressure is relieved, but moisture entry is facilitated
Solution Approach 1:
The exterior body incorporates venting portions with distinct local properties that differ from the main body. These venting portions are strategically positioned and designed with specific characteristics that enable pressure relief while their location and configuration minimize their impact on overall moisture barrier performance.
Solution Approach 2:
Rather than providing complete ventilation that would compromise moisture sealing, the patent implements partial venting through specifically designed venting portions. This partial action provides sufficient pressure relief during reflow mounting while maintaining adequate moisture protection for the capacitor element.
3Ease of manufacture
If the exterior body uses standard sealing material, then manufacturing is simplified, but moisture vapor permeability is insufficient
Solution Approach 1:
The exterior body is constructed using composite materials that combine the benefits of different material properties. The base material provides ease of manufacture and structural integrity, while additional layers or treatments enhance moisture vapor barrier properties. This composite approach allows simultaneous achievement of manufacturing simplicity and superior moisture protection.
Solution Approach 2:
The patent modifies key parameters of the exterior body material, such as adding barrier layers with specific permeability characteristics or applying coatings that reduce moisture vapor transmission. These parameter changes enhance moisture protection while maintaining compatibility with standard manufacturing processes.
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 configuration effectively suppresses moisture entry into the capacitor, preventing poor appearances and internal pressure issues during reflow mounting, while also reducing the likelihood of leak currents and ESR increases.
Implementation Method 1
At least one of the anode frame and the cathode frame has at least one groove on a surface adhered to the exterior body. The at least one groove intersects with an extending direction in which the anode frame or the cathode frame extends from the capacitor element to outside of the exterior body.
Data Source
AI summary
A solid electrolytic capacitor includes a capacitor element, an anode frame, a cathode frame, and an exterior body. The capacitor element includes an anode body, a dielectric body disposed on a surface of the anode body, and a cathode part. The anode frame is electrically connected to the anode body. The cathode frame is electrically connected to the cathode part. The exterior body seals the capacitor element in a state that a part of the anode frame and a part of the cathode frame are exposed from the exterior body. At least one of the anode frame and the cathode frame has at least one groove on a surface adhered to the exterior body. The at least one groove intersects with an extending direction in which the anode frame or the cathode frame extends from the capacitor element to outside of the exterior body.