Solid Electrolytic Capacitor Conductive Sheet ESR Reduction
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Solution Overview
Problem
Conventional solid electrolytic capacitors face challenges in reducing equivalent series resistance (ESR) in high frequency ranges due to issues with conductive adhesive application, leading to increased ESR, leakage current, and potential short circuits, as well as difficulties in forming adhesive layers with high precision.
Innovation Solution
The use of a conductive sheet made from a mixture of flaky silver and epoxy binder resin, applied between cathode layers and shaped to match the lamination planes, which minimizes deformation and gas generation, thereby stabilizing the bonded area and reducing ESR without increasing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conductive adhesive paste is applied to bond cathode layers, then cathode layers can be bonded together, but organic solvent vaporizes during heating causing cavities and increasing ESR
Solution Approach 1:
The patent extracts and removes the organic solvent component from the conductive adhesive formulation, replacing it with a solvent-free or water-based binder system. This eliminates the source of gas generation during heating while maintaining the adhesive's bonding capability, thus preventing cavity formation and reducing ESR.
Solution Approach 2:
The patent changes the chemical composition parameters of the conductive adhesive by substituting organic solvents with alternative binders that do not vaporize at processing temperatures. This parameter change maintains adhesion strength while eliminating harmful gas evolution, resolving the contradiction between bonding quality and ESR reduction.
2Reliability
If conductive adhesive is applied insufficiently, then leakage current is reduced, but bonded area decreases causing increased ESR
Solution Approach 1:
The patent employs a conductive adhesive formulation that achieves optimal bonding with minimal application quantity, effectively treating the adhesive as a highly efficient, low-consumption material. The improved formulation requires less material to achieve the same bonding effect, preventing both insufficient bonding and excessive adhesive application issues.
3Strength
If conductive adhesive is applied too much, then bonded area is increased reducing ESR, but adhesive is pushed out causing protrusions and increasing leakage current
Solution Approach 1:
The patent modifies the rheological and adhesive parameters of the conductive paste to achieve optimal spreadability and bonding efficiency at controlled application thickness. The formulation changes ensure that the adhesive remains within the cathode layer boundaries during processing, preventing protrusion formation while maintaining sufficient bonded area for low ESR and low leakage current.
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 approach results in a solid electrolytic capacitor with reduced ESR and minimized leakage current, achieving a more stable and efficient performance in high-frequency applications.
Implementation Method 1
a conductive sheet made from a mixture of flaky silver and epoxy binder resin, applied between cathode layers
Implementation Method 2
a conductive sheet made from a mixture of flaky silver and epoxy binder resin
Data Source
AI summary
A solid electrolytic capacitor includes a plurality of laminated capacitor elements; an anode terminal connected to an anode portion where anode exposed portions of the capacitor elements are connected together; and a cathode terminal connected to a cathode portion where cathode layers of the capacitor elements are bonded together. Between lamination planes of the cathode layers of the capacitor elements, a conductive sheet is disposed. The capacitor elements are coated with a packaging resin layer in such a manner that a part of the anode terminal and a part of the cathode terminal are exposed.