Package Multi-Layer Thin Film Capacitor Crack Resistance
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Solution Overview
Problem
Conventional multi-layer thin film capacitors are prone to cracks due to external impact and heat, as these stresses are directly transferred through the external electrode to the ceramic sintered body, which is formed from different materials with varying coefficients of expansion, leading to structural integrity issues, especially in applications requiring large capacitance like electric vehicles.
Innovation Solution
The package type multi-layer thin film capacitor incorporates a lead member system with increased surface area connection electrodes and strategically positioned slots in the ceramic sintered body to prevent direct stress transfer, enhancing Equivalent Series Resistance (ESR) and Equivalent Series Inductance (ESL) characteristics by using lead members to manage heat and impact, and allowing for selective employment of ESR and ESL characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external electrode is directly bonded on the soldering pad of the printed circuit board, then the electrical connection is established, but the impact or heat from outside is directly transferred to the ceramic sintered body causing cracks
Solution Approach 1:
The patent introduces a lead member as an intermediary component between the external electrode and the ceramic sintered body. This lead member absorbs and dissipates impact and heat energy, preventing direct transfer to the ceramic structure. The lead member acts as a buffer zone that protects the brittle ceramic from mechanical and thermal stress while maintaining electrical connectivity.
Solution Approach 2:
The patent employs beforehand cushioning by designing a lead member structure that anticipates and prepares for external impacts and heat exposure. The lead member is positioned and configured in advance to absorb and mitigate harmful effects before they can reach the ceramic sintered body, effectively pre-positioning a protective mechanism against potential damage.
2Quantity of substance
If the green sheet layer is manufactured as a thin film to increase the number of layers, then the capacitance is increased, but the surface area becomes significantly wider making the capacitor more susceptible to cracks
Solution Approach 1:
The patent applies segmentation by dividing the capacitor structure into distinct functional zones: the ceramic sintered body containing multiple thin-film layers for capacitance, and the external lead members for connection and protection. This segmentation allows the thin-film section to maximize capacitance while the separate lead member section handles mechanical stress and heat, preventing cracks in the ceramic structure.
3Adaptability or versatility
If the ceramic sintered body is formed of different materials such as dielectric material and metal material, then the multi-layer structure is created, but cracks occur due to different coefficients of expansion
Solution Approach 1:
The lead member serves as an intermediary that accommodates the different coefficients of thermal expansion between dielectric and metal materials. By positioning the lead member between these dissimilar materials, it absorbs the differential expansion stresses, preventing crack formation at the material interfaces while maintaining the multi-material construction necessary for capacitor functionality.
Data Source
AI summary
Provided is a package type multi-layer thin film capacitor for large capacitance, including: a ceramic sintered body formed with slots on one side and another side thereof, respectively; a plurality of first internal electrode layers formed within the ceramic sintered body; a plurality of second internal electrode layers formed within the ceramic sintered body to be positioned between the plurality of first internal electrode layers; a pair of first main connection electrode members inserted into the slots to be connected to the first internal electrode layers or the second internal electrode layers, respectively; a pair of first main lead members inserted into the slots and to be connected to the first main connection electrode members, respectively; and a sealing member sealing the ceramic sintered body to partially expose each of the pair of first main lead members.