Ceramic Capacitor Internal Electrode Splitting Prevention
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Solution Overview
Problem
Ceramic capacitors face reliability issues due to the splitting of internal electrodes and poor contact between electrodes during sintering, caused by reduced metal powder size leading to lower melting points and increased shrinkage differences between electrodes and dielectric material.
Innovation Solution
The ceramic capacitor design incorporates high ceramic-column density portions with ceramic columns spaced 20 μm or less, which are firmly fixed within the capacitor body, ensuring better electrical connection and reliability by using distinct conductive pastes for opposed and extended portions and employing noncontact printing methods like inkjet printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the particle diameter of metal powder in conductive paste is reduced to increase capacitance by increasing internal electrode laminations, then the number of internal electrode layers can be increased, but the melting point of metal powder is lowered and sintered temperature is decreased, causing increased shrinkage difference between internal electrodes and dielectric material, leading to internal electrode splitting or poor contact with external electrodes
Solution Approach 1:
The patent applies local quality by using two different conductive pastes with different metal powder particle diameters in different regions of the internal electrode. The first conductive paste with smaller particle diameter (0.3-1.0 μm) is used for the first internal electrode to achieve fine lamination, while the second conductive paste with larger particle diameter (1.0-3.0 μm) is used for the second internal electrode to maintain high melting point and reduce shrinkage difference, preventing electrode splitting and ensuring reliable contact.
2Productivity
If the thickness of internal electrode is reduced to increase the number of laminations, then capacitance can be increased, but the internal electrode becomes more prone to splitting and poor contact during sintering
Solution Approach 1:
The patent applies parameter changes by adjusting the metal powder particle diameter parameter in the conductive paste formulation. By changing from small particle diameter (0.3-1.0 μm) to large particle diameter (1.0-3.0 μm) in different electrode layers, the sintering behavior and dimensional stability are optimized for each layer, allowing thin electrodes to be formed without splitting while maintaining manufacturing precision.
3Temperature
If the sintered temperature is decreased due to smaller metal powder size, then the conductive paste can be processed at lower temperature, but the difference in shrinkage rate between internal electrodes and dielectric material is increased, causing internal electrode splitting
Solution Approach 1:
The patent applies local quality by using conductive pastes with different metal powder particle diameters in different regions. The first conductive paste (smaller particles) allows lower sintering temperature for the first internal electrode, while the second conductive paste (larger particles) maintains higher sintering temperature for the second internal electrode, ensuring consistent shrinkage rate with dielectric material and preventing splitting.
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 internal electrode splitting and improves contact reliability, maintaining capacitance while enhancing the ceramic capacitor's overall reliability and reducing shrinkage differences between electrodes and dielectric layers.
Implementation Method 1
a sintered temperature of a conductive paste for forming an internal electrode is decreased
Implementation Method 2
when a size of the metal powder in the conductive paste is reduced, a melting point of the metal powder is lowered
Data Source
AI summary
A ceramic capacitor includes first and second first internal electrodes respectively including first and second extended portions that respectively include a plurality of ceramic columns penetrating the first and the second extended portions, respectively, in a thickness direction. The first extended portion includes a first high ceramic-column density portion in which ceramic columns are provided at intervals of about 20 μm or less along the length direction of the extended portion. The second extended portion includes a second high ceramic-column density portion in which ceramic columns are provided at intervals of about 20 μm or less along the length direction of the extended portion.