Segmented Capacitor Electrodes for Thermal Stress Relief
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Solution Overview
Problem
Capacitors experience thermally induced cracking due to mismatched coefficients of thermal expansion between dielectric and end electrodes, leading to failure, especially in environments with wide temperature ranges.
Innovation Solution
The end electrodes are segmented and connected with flexible conductors to allow independent movement, matching the thermal expansion and contraction of the dielectric material while maintaining electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid end electrodes are used to maintain structural stability, then the capacitor body has good mechanical strength, but thermally induced cracking occurs due to mismatched coefficients of thermal expansion between dielectric and end electrodes
Solution Approach 1:
The end electrodes are divided into multiple segments that can move independently relative to each other. This segmentation allows the electrode structure to accommodate thermal expansion and contraction of the dielectric material without generating excessive stress that would cause cracking, while still maintaining overall structural integrity and electrical connectivity through flexible conductors.
Solution Approach 2:
The end electrode structure transitions from a rigid, fixed configuration to a dynamic, adaptable configuration. The segmented electrodes can adjust their positions and orientations in response to thermal changes, allowing the capacitor to maintain reliability across varying temperature conditions while preserving mechanical strength through the coordinated movement of segments.
2Reliability
If the dielectric material is allowed to thermally expand and contract freely, then thermal stress is reduced, but electrical connectivity between end electrodes and internal electrodes may be compromised
Solution Approach 1:
Flexible conductors are used to connect the segmented end electrodes to the internal electrodes. These flexible conductors can accommodate the thermal expansion and contraction of the dielectric material while maintaining continuous electrical connectivity. The flexibility allows the conductors to deform with thermal changes without breaking or losing electrical contact.
Solution Approach 2:
The flexible conductors act as intermediaries between the segmented end electrodes and the internal electrodes. They mediate the thermal expansion and contraction movements, allowing the dielectric to change dimensions freely while ensuring that electrical connectivity is maintained throughout the thermal cycling process.
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 solution reduces thermally induced damage by distributing stress and preventing cracking, enhancing the reliability and capacitance of capacitors across varying temperatures.
Implementation Method 1
the dielectric having a different Coefficient of Thermal Expansion (CTE) than the CTE of the end electrode. In some instances, the CTE of the dielectric is an order of magnitude greater than the CTE of the end electrode. When the CTE of the dielectric is greater than the CTE of the end electrode, the dielectric expands at a greater rate than does the end electrode.
Implementation Method 2
The end spray metal has a coefficient of thermal expansion that is different than a coefficient of thermal expansion of the dielectric material. The first electrode segments are arranged to allow the dielectric material to thermally expand and contract while the segments remain electrically connected to the different portions of the lengthwise edge at the first end.
Data Source
Figure 1~2
Figure 3~4
AI summary
An exemplary embodiment providing one or more improvements includes a capacitor with a segmented end electrode and methods for segmenting an end electrode of a capacitor for reducing or eliminating instances of thermally induced damage of the capacitor.