Multilayer Ceramic Capacitor Electrode Oxidation for Creepage Distance
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with short-circuiting between internal electrodes and the generation of microcracks at the boundary between ceramic dielectric and covering ceramic dielectric layers due to inadequate insulation and creepage distance.
Innovation Solution
The capacitors are designed with a ceramic laminate structure where internal electrodes are arranged with specific metal phases (Ni, Ni-O, Ni-Mg-O) and covered with ceramic dielectric layers, ensuring adequate insulation and microcrack prevention through controlled firing conditions and the use of Mg compounds in the dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the end portions of internal electrodes are exposed to side surfaces of the ceramic laminate, then the acquisition efficiency of electrostatic capacitance is increased, but the creepage distance between internal electrodes is reduced causing short-circuiting
Solution Approach 1:
The patent introduces a new spatial dimension by forming convex portions that protrude from the side surface of the ceramic laminate in the width direction. These convex portions create additional insulation space in the width direction (perpendicular to the lamination direction), effectively increasing the creepage distance between internal electrodes without compromising the capacitance efficiency achieved through electrode exposure.
2Reliability
If covering ceramic dielectric layers are formed on side surfaces to cover exposed internal electrodes, then insulation is improved, but microcracks are likely to be generated at the boundary between ceramic dielectric layers
Solution Approach 1:
The patent applies local quality by forming convex portions with specific material composition and structure only at critical locations where internal electrodes are exposed on the side surfaces. These convex portions have different properties from the main ceramic dielectric layers, providing localized insulation and stress relief exactly where needed, while maintaining the overall structural integrity of the ceramic laminate.
3Reliability
If the thickness of ceramic dielectric layer is increased to prevent short-circuiting, then insulation distance is improved, but the capacitance efficiency is reduced
Solution Approach 1:
Instead of increasing the dielectric layer thickness in the lamination direction (which would reduce capacitance efficiency), the patent creates insulation space in the width direction by forming convex portions that protrude from the side surface. This dimensional approach allows adequate creepage distance to be achieved without compromising the thin dielectric layer design that enables high capacitance efficiency.
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 effectively prevents short-circuiting and microcrack formation, enhancing the insulating properties and reliability of the capacitors.
Implementation Method 1
in the width direction of the ceramic laminate, the one end portion of the first internal electrode includes metal phases of Ni, Ni—O, and Ni—Mg—O arranged in this order from a first internal electrode side to the first side surface of the ceramic laminate
Implementation Method 2
manufacturing methods of such multilayer ceramic capacitors
Data Source
AI summary
In a width direction of a ceramic laminate, one end portion of a first internal electrode and one end portion of a second internal electrode each include metal phases of a Ni region, a Ni—O region, and a Ni—O—Mg region disposed in this order from a first internal electrode side and a second internal electrode side, respectively, to a first side surface of the ceramic laminate. The other end portion of the first internal electrode and the other end portion of the second internal electrode each include metal phases of a Ni region, a Ni—O region, and a Ni—O—Mg region disposed in this order from the first internal electrode side and the second internal electrode side, respectively, to a second side surface of the ceramic laminate.