Monolithic Ceramic Capacitor Inner Electrode Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Monolithic ceramic capacitors face reliability issues due to cracking caused by the expansion of inner electrodes during the baking process of outer electrode formation, which compromises the mechanical and thermal stress resistance of the ceramic element body.
Innovation Solution
Incorporating a gap between inner electrodes with a width of 0.2 μm to 2 μm, which can be filled with air or materials like Ni or Ni-Cu alloy, to allow for expansion in the length direction while restricting expansion in the stacking and width directions, thereby preventing cracks from forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inner electrodes are formed without gaps, then electrical connectivity and capacitance are improved, but cracks occur due to expansion during baking
Solution Approach 1:
The patent introduces gaps that segment the inner electrodes in the stacking direction, dividing the continuous electrode structure into separate sections. This segmentation allows each section to expand independently during the baking process without generating harmful stresses, while maintaining electrical connectivity through the outer electrodes and preventing crack formation in the ceramic element body.
2Reliability
If gaps are introduced between inner electrodes, then expansion stress is reduced and cracks are prevented, but electrical connectivity may be compromised
Solution Approach 1:
The patent specifies precise parameter ranges for the gap width (0.2 μm to 2 μm) and the proportion of dielectric layers with gaps (5% to 90%). By controlling these parameters within defined ranges, the design balances the need for expansion accommodation with maintaining sufficient electrical connectivity, ensuring reliable capacitor operation while preventing crack formation.
3Reliability
If gaps are provided in all dielectric layers, then expansion restriction is maximized, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies gaps to only a proportion of the dielectric layers (5% to 90%) rather than all layers. This partial application of the gap structure provides sufficient expansion accommodation to prevent cracks while reducing manufacturing complexity and cost compared to implementing gaps in every dielectric layer, thereby improving productivity.
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
The solution effectively restricts the expansion of inner electrodes, preventing cracks and enhancing the reliability and durability of the ceramic capacitors by allowing controlled expansion in the length direction while maintaining structural integrity in the width and thickness directions.
Implementation Method 1
when the conductive paste for forming the outer electrodes is baked in a manufacturing process thereof, the inner electrodes 102 may expand in a stacking direction (thickness direction or T direction) of the inner electrodes 102 and a width direction (direction orthogonal to a direction in which the inner electrodes extend or W direction) of the inner electrodes 102
Data Source
AI summary
A monolithic ceramic capacitor includes an outer electrode arranged on a ceramic element body including inner electrodes, and a dielectric layer present between a pair of the inner electrodes adjacent in a stacking direction and extending to one of a pair of end surfaces of the ceramic element body that defines an inter-electrode dielectric layer. A gap extending in a direction connecting the inner electrodes sandwiching the inter-electrode dielectric layer is present in about 5% to about 90% of inter-electrode dielectric layers in the ceramic element body at a position near or adjacent to at least one of the pair of end surfaces of the ceramic element body.