Solid Electrolytic Capacitor Terminal Design for Low ESR
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Solution Overview
Problem
Solid electrolytic capacitors face structural constraints that limit capacitance expansion and increase impedance due to the exposure of anode and cathode terminals, leading to higher ESR values.
Innovation Solution
A solid electrolytic capacitor design where the anode terminal is bent at an acute angle to reduce signal length, with a conductive paste connecting the cathode terminal to the capacitor element, and a molding portion exposing only the lower surfaces of the terminals to minimize external exposure and maximize contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the anode terminal and cathode terminal are exposed through both side surfaces of the capacitor, then the assembly is simplified, but the lead frame length increases causing increased ESR
Solution Approach 1:
The patent transitions from exposing terminals through both side surfaces (vertical arrangement) to exposing terminals through the lower surface only (horizontal arrangement). The anode terminal and cathode terminal are positioned on the same lower surface, changing the spatial dimension of terminal exposure and reducing the lead frame length required for electrical connection.
2Reliability
If the volume of the tantalum element is expanded to increase capacitance, then capacitance improves, but structural constraints prevent further expansion
Solution Approach 1:
The patent repositions the anode terminal from the side surface to the lower surface along with the cathode terminal. This dimensional rearrangement creates additional space within the capacitor structure, allowing the tantalum element volume to be expanded for increased capacitance without compromising the electrical connection structure.
3Reliability
If the lead frame length is reduced to decrease ESR, then ESR improves, but the electrical connection between terminals and capacitor element becomes more difficult
Solution Approach 1:
The patent merges the anode terminal and cathode terminal positions onto the same lower surface plane. This consolidation allows both terminals to be electrically connected to the capacitor element from the same side, simplifying the manufacturing process while maintaining short lead frame lengths for low ESR.
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 enhances capacitance by up to 20% and reduces ESR by 2% or more compared to typical capacitors, while preventing appearance defects and ensuring reliable electrical connections.
Implementation Method 1
The cathode terminal may be electrically connected to the capacitor element through a conductive paste
Implementation Method 2
electrically connecting a bending portion of an anode terminal, which functions as an anode lead frame, to a capacitor element at an acute angle to reduce an electrical signal length
Data Source
AI summary
The present invention relates to a solid electrolytic capacitor and a production method thereof.A solid electrolytic capacitor of the present invention includes: a capacitor element having an anode wire inserted in one side surface thereof; a cathode terminal disposed on one side under the capacitor element to be electrically connected to the capacitor element; an anode terminal disposed on the other side under the capacitor element and having a bending portion integrally formed to be inclined to the capacitor element for electrical connection with the anode wire; and a molding portion surrounding the outside of the capacitor element and formed to expose lower surfaces of the cathode terminal and the anode terminal.