Solid Electrolytic Capacitor Terminal Design
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Solution Overview
Problem
Conventional solid electrolytic capacitors face manufacturing complexities due to the need for bending terminals and have issues with solder wettability and equivalent series resistance (ESR) or equivalent series inductance (ESL) due to terminal lengths, as well as exposure of insulating substrate edges affecting solder fillet formation and connection reliability.
Innovation Solution
A solid electrolytic capacitor design where the capacitor element is mounted on an insulating substrate with anode and cathode terminals formed on both surfaces, connected by conductive layers on the substrate's edge, eliminating the need for resin filling in vias and improving solder wettability by exposing conductive layers from the enclosure resin, thus simplifying manufacturing and enhancing connection quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor element is coated with an enclosure resin and terminals are bent along the outer peripheral surface, then the terminals can be positioned along the lower surface, but the manufacturing process becomes complicated and the equivalent series resistance (ESR) and equivalent series inductance (ESL) increase due to longer terminal lengths
Solution Approach 1:
The patent transitions from a three-dimensional bending process to a two-dimensional planar configuration by forming the anode terminal and cathode terminal along the lower surface of the enclosure resin in a straight line, eliminating the need for complex bending operations while maintaining proper terminal positioning and connection reliability
2Manufacturing precision
If the enclosure resin of appropriate thickness is interposed between the lower surface of the capacitor element and the lower surface electrodes, then the terminals can be properly positioned, but the equivalent series resistance (ESR) and equivalent series inductance (ESL) increase due to increased terminal lengths
Solution Approach 1:
The patent optimizes the geometric parameters of the terminal configuration by arranging the anode terminal and cathode terminal in a collinear fashion along the lower surface, minimizing the terminal length while maintaining the required insulation distance through the enclosure resin, thereby reducing ESR and ESL without compromising positioning precision
3Ease of manufacture
If the insulating substrate edges are exposed at positions above the lower surface electrodes, then the substrate structure is simplified, but the solder wettability of the lower surface electrodes deteriorates and fillet formation is poor
Solution Approach 1:
The patent applies different structural characteristics to different regions: the insulating substrate maintains its simplified structure in the central area, while the enclosure resin is extended to form side surfaces that expose the terminals in specific local regions, creating optimal conditions for solder wettability and fillet formation without compromising overall structural simplicity
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 design simplifies manufacturing, reduces ESR and ESL, and improves solder wettability, ensuring better connection reliability and easier solder fillet formation on the wiring board.
Implementation Method 1
an anode conductive layer which electrically connects the first anode section and the second anode section to each other, and a cathode conductive layer which electrically connects the first cathode section and the second cathode section to each other
Implementation Method 2
The anode section and the cathode section of the capacitor element are electrically connected to the first anode section and the first cathode section, respectively
Data Source
AI summary
A solid electrolytic capacitor includes a capacitor element coated with an enclosure resin, and an insulating substrate in which an anode terminal and a cathode terminal are formed. The anode terminal includes a first anode section formed on a first surface of the insulating substrate, a second anode section formed on a second surface of the insulating substrate, and an anode conductive layer which is formed on a side edge surface of the insulating substrate to electrically connect there anode sections to each other. The cathode terminal includes a first cathode section formed on the first surface, a second cathode section formed on the second surface, and a cathode conductive layer which is formed on the side edge surface of the insulating substrate to electrically connect there cathode sections to each other. And the anode conductive layer and the cathode conductive layer are exposed from the enclosure resin.