Electrolytic Capacitor Lead-Out Chamfers to Prevent Exterior Cracks
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Solution Overview
Problem
Electrolytic capacitors face reliability issues due to cracking of the exterior body when exposed to high temperatures, leading to reduced sealability and reliability, primarily at the interface where the exterior body and lead-out portions contact.
Innovation Solution
The electrolytic capacitor design incorporates a chamfered shape for at least a part of the lead-out portion's corner portion, alleviating stress concentration and suppressing crack formation by forming a chamfered shape corner portion in the cross-section parallel to the outer surface where the lead-out portion is exposed, which is covered by the exterior body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead-out portion has a sharp corner shape, then the exterior body can be tightly sealed around the lead-out portion, but stress concentration occurs at the corner portion leading to crack formation in the exterior body
Solution Approach 1:
The patent applies curvature by forming a chamfered shape at the corner portion of the lead-out portion instead of using a sharp corner. This chamfered shape creates a gradual transition surface that eliminates stress concentration points, preventing crack formation in the exterior body while maintaining proper sealing. The curved/chamfered geometry distributes mechanical stress evenly across the interface between the lead-out portion and exterior body.
2Volume of stationary object
If the exterior body is made thin to reduce size, then the capacitor can be miniaturized, but the exterior body becomes more susceptible to cracking at the interface with the lead-out portion
Solution Approach 1:
The chamfered shape corner portion provides a stress-distributing geometry that allows the exterior body to be made thinner without compromising structural integrity. By eliminating sharp corners that act as stress concentrators, the design enables miniaturization while maintaining crack resistance even in thin-walled constructions.
Solution Approach 2:
The patent applies local quality by modifying only the corner portion of the lead-out portion with a chamfered shape, while the rest of the structure can be optimized for minimal thickness. This localized geometric modification provides enhanced stress distribution precisely where needed at the interface, allowing the exterior body to be thin overall without sacrificing reliability at critical stress points.
Data Source
AI summary
An electrolytic capacitor includes a capacitor element, an exterior body covering the capacitor element, an anode terminal electrically connected to an anode body of the capacitor element, and a cathode terminal electrically connected to a cathode portion of the capacitor element. Each of the anode terminal and the cathode terminal includes a connection portion in contact with the capacitor element, a lead-out portion led out from the connection portion to an outer surface of the exterior body, and an external terminal portion disposed along the outer surface of the external body and having an exposed surface exposed from the external body. At least a part of a covered portion of the lead-out portion, the covered portion being covered with the exterior body, has a cross-sectional shape including a chamfered shape corner portion in a cross section parallel to a surface region of the outer surface of the exterior body where the lead-out portion is led out.