Multilayer Electrolytic Capacitor Layout for Lower ESR Contact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multilayer electrolytic capacitors, displacement of cathode ends during stacking leads to a small exposed area, resulting in high equivalent series resistance (ESR) due to poor contact between cathodes and external electrodes, which cannot be effectively reduced.
Innovation Solution
The electrolytic capacitor design includes a stack with cathodes displaced in a specific manner, where the first cathode end is closest to the second external electrode, and the second cathode end is second closest, with a first external electrode connected to the anode and a second external electrode connected to both cathodes, ensuring optimal contact area even when cathodes are displaced, and using a sealing resin to form a sealed body with exposed anodes and electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stack is sealed by a sealing resin before forming an external electrode connected to the cathodes, then the capacitor elements are protected and sealed, but the area of the cathodes exposed from the sealing resin becomes small due to displacement, resulting in high ESR
Solution Approach 1:
The external electrode is formed on the cathodes before the sealing resin is applied. This preliminary formation of the electrode ensures that even if cathodes are displaced during stacking, the electrode material can bridge the gaps and maintain adequate contact area. The sealing resin is then applied to seal the stack, but the electrode connection is already established.
Solution Approach 2:
The external electrode acts as an intermediary element between the displaced cathodes and the external circuit. By forming this electrode layer before sealing, it serves as a mediator that can accommodate the displacement of cathodes while maintaining electrical connection, thus preventing high ESR caused by poor contact.
2Quantity of substance
If multiple capacitor elements are stacked to form a multilayer electrolytic capacitor, then the capacitance is increased, but the cathode ends become displaced at the end surface, reducing the contact area with external electrodes
Solution Approach 1:
The external electrode is formed on the cathodes before the sealing resin is applied. This preliminary formation of the electrode ensures that even if cathodes are displaced during stacking, the electrode material can bridge the gaps and maintain adequate contact area. The sealing resin is then applied to seal the stack, but the electrode connection is already established.
Solution Approach 2:
The patent changes the formation sequence of components - specifically, the external electrode is formed before the sealing resin is applied. This parameter change in the manufacturing process allows the electrode to be deposited on potentially displaced cathodes, and the subsequent sealing preserves this configuration rather than requiring perfect alignment.
Data Source
AI summary
An electrolytic capacitor that includes a stack having multiple capacitor elements stacked in a thickness direction perpendicular to a length direction, wherein a first end of a first cathode is first closest to a second external electrode among all of ends of the cathodes of the multiple capacitor elements, a second end of a second cathode is second closest to the second external electrode, and an end of the second external electrode is closer to a first external electrode than the second end of the second cathode.