Wound Capacitor Structure for Electrostriction Crack Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face issues such as cracks due to electrostriction and step differences caused by variations in internal electrode stacking, especially under high temperature and high voltage conditions, which can lead to failure and reduced reliability.
Innovation Solution
A capacitor component design featuring a dielectric layer and internal electrodes alternately disposed and wound around an axis, with external electrodes on opposing surfaces, minimizing shrinkage differences and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multilayer ceramic capacitors are miniaturized with higher capacitance, then capacitance per unit volume is improved, but cracks occur due to electrostriction under high temperature and high voltage conditions
Solution Approach 1:
The capacitor is divided into multiple layers with internal electrodes and dielectric layers stacked alternately. This segmentation allows the structure to better distribute and manage electrostriction stresses, reducing crack formation while maintaining high capacitance density in the miniaturized component.
Solution Approach 2:
The capacitor uses composite material structure combining conductive internal electrodes with dielectric layers having specific piezoelectric coefficients. By selecting materials with appropriate piezoelectric properties, the composite structure suppresses electrostriction-induced cracks while achieving high capacitance in a small volume.
2Ease of manufacture
If internal electrodes are stacked with variations in degree, then manufacturing flexibility is improved, but step differences occur in margin portions
Solution Approach 1:
The patent addresses step differences by extending electrode patterns onto side surfaces of the capacitor body, utilizing the third dimension (side surfaces) to compensate for stacking variations. This dimensional extension ensures complete electrode coverage regardless of stacking precision, eliminating step differences while maintaining manufacturing flexibility.
3Power
If dielectric layer shrinkage and expansion occur due to piezoelectricity, then capacitance response is improved, but cracks form between internal electrodes and dielectric
Solution Approach 1:
The patent optimizes the piezoelectric coefficient parameters of the dielectric layer to control shrinkage and expansion behavior. By carefully selecting dielectric materials with appropriate piezoelectric properties, the structure achieves good capacitance response while the stress from shrinkage/expansion remains within adhesive strength limits, preventing crack formation.
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
Suppresses crack formation and improves capacitance and reliability by stabilizing the structure against electrostriction, while maintaining effective volume and productivity.
Implementation Method 1
cracks may occur due to shrinkage and expansion (electrostriction) of a dielectric layer due to piezoelectricity
Data Source
AI summary
A capacitor component comprises a body that includes a dielectric layer and first and second internal electrodes alternately disposed with the dielectric layer interposed between them. The internal electrodes and dielectric layer are wound around an axis which extends in a second direction. The component further includes external electrodes disposed on opposing third and fourth surfaces of the body in the second direction. The body also has a first surface and a second surface opposing each other in a first direction, which is perpendicular to the second direction, and a fifth surface and a sixth surface opposing each other in a third direction, perpendicular to both the first and second directions.