Tantalum Capacitor Lead Frame Inclination Angle Design
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Solution Overview
Problem
Conventional tantalum capacitors face limitations in capacitance due to internal lead frames reducing the tantalum material volume and increased ESR from multiple contact materials, as well as reduced internal volume fraction when terminals are led out without a frame, leading to compromised performance in mechanical strength and breakdown voltage.
Innovation Solution
A tantalum capacitor design featuring a tantalum body with a tantalum wire exposed and surrounded by a molding portion, an anode lead frame with a specific inclination angle, and a cathode lead frame spaced apart, which increases the tantalum body volume, reduces ESR, and enhances mechanical strength and breakdown voltage by optimizing lead frame geometry and contact areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an internal lead frame is used to connect the tantalum material and the electrode, then the terminal can be extracted to the outside, but the space occupied by the tantalum material in the molding portion is reduced, limiting capacitance
Solution Approach 1:
The patent removes the internal lead frame structure from the capacitor design. Instead of using a lead frame to connect the tantalum material to the electrode, the terminal is directly extracted to the outside, eliminating the space occupation problem and maximizing the tantalum material volume for higher capacitance.
Solution Approach 2:
The patent changes the spatial arrangement by positioning the cathode lead frame on the side surface of the product rather than inside the molding portion. This dimensional reorganization allows the anode lead frame to be directly connected to the tantalum material without space constraints, increasing the effective tantalum material volume.
2Volume of moving object
If a terminal is led out to the outside without a frame, then the tantalum material volume is maximized, but the ESR of the capacitor is increased due to increased contact resistance from multiple contact materials
Solution Approach 1:
The patent extracts the lead frame from the internal structure and positions it on the side surface, eliminating unnecessary contact interfaces. This reduces the number of contact materials and their associated contact resistances, thereby lowering the overall ESR of the capacitor.
3Strength
If a cathode lead frame is located on the side surface of the product to secure welding distance, then the terminal can be connected, but the internal volume fraction of the tantalum material is reduced, deteriorating capacitance
Solution Approach 1:
The patent repositions the cathode lead frame from inside the molding portion to the side surface of the product. This spatial relocation maintains the necessary welding distance for mechanical strength while maximizing the internal volume fraction available for tantalum material, thereby preserving capacitance.
Data Source
AI summary
A tantalum capacitor includes a tantalum body including tantalum powder, and having a tantalum wire exposed to one end surface; a molding portion including fifth and sixth surfaces opposed in a first direction, third and fourth surfaces opposed in a second direction, and first and second surfaces opposed in a third direction, and formed to surround the tantalum body; an anode lead frame exposed to the second surface of the molding portion, and connected to the tantalum wire; and a cathode lead frame spaced apart from the anode lead frame, and exposed to the second surface of the molding portion. The anode lead frame includes a first connection portion and a first bent portion, and the first bent portion forms an inclination angle within a range of less than 70° toward the tantalum body, based on the first connection portion.