Composite Internal Electrodes for Thin High-Capacity MLCCs
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Solution Overview
Problem
Multi-layer ceramic capacitors face issues with internal electrode breakage during the sintering process due to mismatched sintering temperatures and coefficients of linear expansion, leading to discontinuous surfaces and voids.
Innovation Solution
Incorporation of a sintered structure using a metal-carbon composite and metal paste to form internal electrodes, which enhances mechanical reliability and prevents breakage during the sintering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal paste is used for internal electrodes, then the sintering process can be completed, but the internal electrodes break due to mismatched sintering temperatures and coefficients of linear expansion
Solution Approach 1:
The internal electrode uses a composite material consisting of metal particles (such as nickel or copper) dispersed in a glass matrix. This composite structure combines the high electrical conductivity of metal with the thermal stability and mechanical strength of glass, allowing the electrode to withstand the sintering process without breaking while maintaining electrical functionality.
Solution Approach 2:
The invention modifies the chemical composition parameters of the internal electrode material, specifically adjusting the ratio of metal particles to glass matrix and selecting specific glass compositions. These parameter changes enable the electrode to have matched thermal expansion coefficients with the ceramic body, preventing breakage during sintering while maintaining conductivity.
2Volume of moving object
If the capacitor size is reduced to meet compact device requirements, then the component becomes more suitable for modern electronics, but the capacity decreases
Solution Approach 1:
The invention applies different material properties to different regions of the capacitor. The internal electrode uses a composite material with locally optimized properties: high metal content for electrical conductivity in the electrode regions, while the glass matrix provides structural support. This local quality differentiation allows the capacitor to maintain high capacity in a compact form by maximizing the active electrode material where needed.
Solution Approach 2:
The composite internal electrode material enables higher volumetric capacity by efficiently utilizing space. The metal particles provide conductive pathways while the glass matrix fills the interstitial spaces, allowing for higher electrode density and better space utilization, thereby achieving high capacity in a reduced volume.
3Length of stationary object
If the thickness of the capacitor is reduced, then the component becomes more compact, but the structural integrity during sintering deteriorates
Solution Approach 1:
The glass-matrix composite structure provides enhanced mechanical strength and flexibility. The glass matrix acts as a binding phase that holds the metal particles together, creating a more robust electrode structure that can withstand the thermal and mechanical stresses of the sintering process even when the overall capacitor thickness is reduced.
Solution Approach 2:
By adjusting the glass composition parameters (such as adding specific oxides like B2O3 or SiO2), the viscosity and thermal properties of the glass matrix are optimized. This enables the thin electrode structure to maintain sufficient mechanical integrity during sintering while allowing for reduced overall capacitor thickness.
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 results in a multi-layer ceramic capacitor with a large capacity and reduced thickness, maintaining structural integrity and electrical conductivity.
Implementation Method 1
a sintered structure that includes a metal-carbon composite and metal paste
Data Source
AI summary
A multi-layer ceramic capacitor includes a ceramic body and an internal electrode formed inside the ceramic body and including a sintered structure of a metal-carbon composite and metal paste.