Solid Electrolytic Capacitor with Adhesive Bonding and Insulated Lead Frames
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Solution Overview
Problem
Conventional solid electrolytic capacitors face issues with heat damage during manufacturing, leading to increased costs and reduced capacitance due to high-temperature welding and large lead frame sizes, which affect the capacitor's size and performance.
Innovation Solution
A solid electrolytic capacitor design with an anode wire inserted into a lower portion of the capacitor element, a cathode extraction layer, and lead frames bonded using insulating and conductive adhesives, with a molding portion exposing the lead frames' surfaces and using electroless plating for terminals, allowing for reduced size and enhanced capacitance while minimizing heat exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct welding of anode wire and anode lead frame is performed, then electrical connection is achieved, but high-temperature heat damages the capacitor element and destroys dielectrics
Solution Approach 1:
The patent introduces an intermediate bonding structure consisting of an anode lead frame with a pressing portion that mechanically and electrically connects the anode wire to the capacitor element without direct welding. The anode wire is pressed and bonded to the anode lead frame's pressing portion, which then connects to the capacitor element, serving as a heat-isolating intermediary that prevents high-temperature damage while maintaining electrical connection reliability.
2Reliability
If large lead frames are used, then electrical connection and structural support are ensured, but the capacitor element size is reduced and capacitance decreases
Solution Approach 1:
The patent transitions from planar lead frame structures to a three-dimensional configuration where the anode lead frame extends vertically with a pressing portion that protrudes upward. This dimensional change allows the lead frame to provide structural support and electrical connection in a compact vertical arrangement, maximizing the capacitor element's horizontal space within the epoxy case while maintaining connection reliability.
Solution Approach 2:
The anode lead frame is segmented into distinct functional portions: a base portion embedded in the epoxy case for structural support, and a pressing portion protruding upward for electrical connection. This segmentation allows each portion to be optimized independently - the base portion provides support without occupying capacitor element space, while the pressing portion enables reliable connection with minimal space requirements.
3Ease of manufacture
If simplified manufacturing process is implemented, then manufacturing cost is reduced, but manufacturing precision and quality control become more challenging
Solution Approach 1:
The anode lead frame is pre-formed with the pressing portion and bonding structure before assembly. The anode wire is pre-positioned and bonded to the pressing portion in a controlled manner before the final epoxy molding. This preliminary preparation of connection structures allows for better quality control in controlled environments while simplifying the final assembly process, reducing overall manufacturing complexity without sacrificing precision.
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 design simplifies the manufacturing process, reduces manufacturing costs, maximizes capacitance, and achieves a low Equivalent Series Resistance (ESR) characteristic, addressing heat-related damage and size constraints.
Implementation Method 1
an insulating adhesive, and a cathode bonding portion, which is bonded to the capacitor element through a conductive adhesive
Implementation Method 2
an insulating adhesive, and a cathode bonding portion, which is bonded to the capacitor element through a conductive adhesive
Implementation Method 3
using electroless plating for terminals
Data Source
AI summary
Provided is a solid electrolytic capacitor including a capacitor element with a positive polarity; an anode wire inserted and connected to a lower portion of the capacitor element; a cathode extraction layer formed on the capacitor element; an anode lead frame provided on one side of the lower surface of the capacitor element so as to be electrically insulated from the cathode extraction layer, the anode lead frame having an insertion portion into which a projecting lower portion of the anode wire is inserted; a cathode lead frame provided on the other side of the lower surface of the capacitor element so as to be electrically connected to the cathode extraction layer; a molding portion formed to surround the capacitor element and exposing the lower end surface of the anode wire, the lower surface of the anode lead frame, and the lower surface of the cathode lead frame; an anode lead terminal provided on the molding portion so as to be electrically connected to the lower end surface of the anode wire and the lower surface of the anode lead frame; and a cathode lead terminal provided on the molding portion so as to be electrically connected to the lower surface of the cathode lead frame.