Multilayer Ceramic Electrode Structure for Short-Circuit Insulation Recovery
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Solution Overview
Problem
Existing multilayer ceramic electronic devices face challenges in maintaining insulation and preventing heat generation after a short circuit, with a need for more versatile designs that ensure freedom in element body design.
Innovation Solution
A multilayer ceramic electronic device with external electrodes comprising a first layer containing a first insulator phase and first metal phases, and a second layer with a second insulator phase and second metal phases, where the area ratio of the first metal phases is between 8% and 30%, and the second metal phases have an average aspect ratio of 3.5 or more, allowing for insulation restoration properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal structure (compositions of ceramic layers and internal electrode layers) is optimized to prevent post-short circuit heat generation, then insulation can be maintained after short circuit, but degree of freedom in designing the element body is restricted
Solution Approach 1:
The external electrode is divided into two distinct layers: a first layer containing a first insulator phase and first metal phases, and a second layer containing a second insulator phase and second metal phases. This segmentation allows each layer to perform specific functions - the first layer provides insulation restoration through crack formation that cuts conductive paths, while the second layer provides electrical connection, thereby maintaining reliability without restricting element body design freedom
Solution Approach 2:
Different regions of the external electrode are given different properties - the first layer has specific metal phase area ratios (6-30%) and aspect ratios (3.5 or more) to enable insulation restoration, while the second layer has different composition for optimal electrical connection. This local differentiation allows the device to maintain insulation after short circuit while preserving design freedom for the element body
2Reliability
If a conventional single-layer external electrode structure is used, then manufacturing is simpler, but insulation cannot be maintained after short circuit causing heat generation
Solution Approach 1:
The external electrode is segmented into two layers with distinct compositions and functions. The first layer contains a first insulator phase and first metal phases with controlled area ratios (6-30%) and aspect ratios (3.5 or more), while the second layer contains a second insulator phase and second metal phases. This segmentation enables insulation restoration through crack-induced conductive path cutting in the first layer, achieving reliability without excessive complexity
Solution Approach 2:
The external electrode uses composite material structures - each layer combines insulator phases and metal phases with specific area ratios. The first layer's composite structure enables it to form cracks that cut conductive paths while maintaining electrical connection through the second layer, thus preventing heat generation after short circuit with manageable structural complexity
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 device maintains insulation and prevents heat generation from the element body after a short circuit by cutting conductive paths through cracks in the first layer, ensuring effective insulation restoration.
Implementation Method 1
the first metal phases have an average aspect ratio of 3.5 or more... can have insulation restoration properties... can maintain insulation even when the multilayer ceramic electronic device is energized after being short-circuited
Data Source
AI summary
A multilayer ceramic electronic device includes an element body including a ceramic layer and an internal electrode layer, and an external electrode formed on an outer surface of the element body and electrically connected to part of the internal electrode layer. The external electrode includes a first layer in direct contact with the element body and containing a first insulator phase and first metal phases, and a second layer in contact with an outer surface of the first layer and containing a second insulator phase and second metal phases. An area ratio of the first metal phases in the first layer is more than 8% and 30% or less. An area ratio of the second metal phases in the second layer is larger than the area ratio of the first metal phases in the first layer. The first metal phases have an average aspect ratio of 3.5 or more.