Laminated Ceramic Capacitor Thermal Shock Resistance via Mg-Li Oxide
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Solution Overview
Problem
Laminated ceramic capacitors face challenges in maintaining thermal shock resistance and high temperature load characteristics when dielectric ceramic layers are reduced in thickness and the number of layers is increased, leading to potential defects such as cracks during rapid temperature changes.
Innovation Solution
Incorporating a crystalline oxide containing Mg and Li in either the dielectric ceramic layers or internal electrodes, with 70% or more of this oxide in contact with Ni, and adding specific rare earth elements and metal elements to improve thermal shock resistance and high temperature load characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dielectric ceramic layer is reduced in thickness to increase the number of stacked layers, then the capacitance increases and size is reduced, but the thermal shock resistance degrades causing cracks during rapid temperature changes
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic layer by incorporating specific amounts of Mg (0.01-5 mol%) and Li (0.01-5 mol%) along with rare earth elements and metal elements. This compositional parameter change modifies the thermal and mechanical properties of the ceramic, enabling it to maintain high thermal shock resistance even when the layer thickness is reduced to 1 μm or less, thus resolving the contradiction between increased capacitance and degraded thermal shock resistance
Solution Approach 2:
The patent creates a composite dielectric ceramic material by combining barium titanate base ceramic with multiple additive elements (Mg, Li, rare earth elements, and metal elements). This composite structure synergistically improves both the thermal shock resistance and dielectric properties, allowing the capacitor to achieve high capacitance with thin layers while maintaining reliability under thermal stress
2Volume of moving object
If the dielectric ceramic layer is reduced in thickness to increase the number of stacked layers, then the size is reduced, but the high temperature load characteristics may deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of the dielectric ceramic by adding specific elements (Mg, Li, rare earth elements, and metal elements) in controlled amounts. This parameter change enhances the material's thermal stability and structural integrity, enabling the capacitor to maintain excellent high temperature load characteristics even with reduced layer thickness and increased layer count, thus achieving miniaturization without sacrificing reliability
3Productivity
If the number of stacked layers is increased to increase capacitance, then the capacitance increases, but the manufacturing complexity increases
Solution Approach 1:
The patent optimizes the chemical composition parameters of the dielectric ceramic and interface layer to achieve stable sintering characteristics and controlled grain growth. This parameter optimization allows for the formation of uniform, thin dielectric layers with consistent properties across hundreds of stacked layers, reducing variability and defect rates, thus enabling high-capacitance multi-layer structures to be manufactured reliably without excessive complexity
Data Source
AI summary
A laminated ceramic capacitor which provides favorable properties and characteristics such as dielectric characteristics, insulation properties, temperature characteristics, and high temperature load characteristics and provides favorable thermal shock resistance, even when dielectric ceramic layers are reduced in layer thickness to increase the number of layers has dielectric ceramic layers containing, as their main constituent, a barium titanate based compound represented by the general formula ABO3 and internal electrodes containing Ni as their main constituent, which are stacked alternately. A crystalline oxide containing at least Mg and Li is present in at least either one of the internal electrodes and the dielectric ceramic layers. The crystalline oxide is preferably present mostly in contact with Ni in the internal electrodes.