Electrolytic Capacitor Electrode Layout for Lower ESL and ESR
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Solution Overview
Problem
Solid electrolytic capacitors face issues with high equivalent series inductance (ESL) and equivalent series resistance (ESR) due to long lead paths and resistance paths between the anode and cathode.
Innovation Solution
The electrolytic capacitor design includes a capacitor body with a short anode line exposed on one end surface and a cathode layer led out to the bottom surface, with external electrodes formed on these surfaces, reducing the path length and improving connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lead frame is used to lead out anode and cathode to external electrodes, then the capacitor structure is complete and functional, but the equivalent series inductance (ESL) increases due to long paths
Solution Approach 1:
The patent transitions from a planar lead frame structure to a three-dimensional configuration where the anode wire passes through the capacitor body and the cathode layer is led out to the bottom surface. This spatial reconfiguration shortens the current path by utilizing vertical and lateral dimensions simultaneously, reducing ESL while maintaining electrical connectivity.
Solution Approach 2:
The patent extracts the anode wire from the traditional lead frame structure and makes it pass directly through the capacitor body to the external electrode. This eliminates the unnecessary lead frame path, directly connecting the anode to the external electrode and reducing the inductive loop area.
2Stability of the object's composition
If one end surface of the anode wire is embedded in the porous sintered body, then the capacitor structure is stable, but the resistance path between anode and cathode becomes long, increasing equivalent series resistance (ESR)
Solution Approach 1:
The patent changes the anode wire configuration from a single-ended embedded structure to a through-wire structure that passes through the capacitor body. This allows the cathode layer to be positioned closer to the anode wire, shortening the resistance path while maintaining structural stability through proper anchoring at both ends.
Solution Approach 2:
The anode wire is pre-positioned to pass through the capacitor body before final assembly, ensuring optimal alignment and minimal resistance path. The cathode layer is then applied in proximity to the anode wire, pre-establishing short electrical paths before sealing.
Data Source
AI summary
The electrolytic capacitor includes a capacitor body, the capacitor body including: a first end surface; a second end surface opposite to the first end surface; a bottom surface adjacent to the first end surface and the second end surface; a capacitor element including an anode line passing therethrough, a dielectric layer, and a cathode layer on the dielectric layer; and a sealing material covering the capacitor element, wherein the anode line has a first end exposed on the first end surface of the capacitor body, the electrolytic capacitor includes an anode external electrode on the first end surface of the capacitor body, the anode external electrode is connected to the first end of the anode line, the cathode layer is electrically led out to the bottom surface of the capacitor body, the electrolytic capacitor includes a cathode external electrode on the bottom surface of the capacitor body, and the cathode external electrode is electrically connected to the cathode layer.