Terminal Adhesion Segmentation for Vibration Resistance
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Solution Overview
Problem
In electronic devices, especially power conversion devices, external connection terminals with different potentials are prone to breaking due to thermal stress-induced vibration, as the distances between these terminals and the sealing resin body are minimized to reduce inductance, leading to potential disconnection.
Innovation Solution
The introduction of a surface on the external connection terminals with a higher adhesion part and a lower adhesion part, where the higher adhesion part has a roughened surface formed by an uneven oxide film and the lower adhesion part has a lower adhesion to the sealing resin body, allowing the sealing resin body to peel from the lower adhesion part during vibration, thereby increasing the vibration distance and preventing terminal breakage while maintaining the creeping distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the distance between the external connection terminal and the sealing resin body is reduced to minimize inductance, then the inductance is reduced, but the external connection terminal becomes susceptible to breaking due to vibration from thermal stress
Solution Approach 1:
The surface of the external connection terminal is segmented into distinct adhesion zones: a higher adhesion part (first region) and a lower adhesion part (second region). This segmentation allows the terminal to maintain secure attachment where needed while providing a controlled release zone that absorbs vibration stress, preventing terminal breakage without increasing overall distance
Solution Approach 2:
Different regions of the external connection terminal surface are assigned different adhesion qualities. The first region has higher adhesion to ensure stable electrical connection, while the second region has lower adhesion to allow controlled peeling during vibration. This local differentiation resolves the contradiction by providing both secure attachment and vibration absorption in appropriate locations
2Strength
If the sealing resin body is made to adhere strongly to the external connection terminal, then the terminal is secured, but the terminal cannot accommodate vibration without breaking
Solution Approach 1:
The adhesion strength is differentiated across the terminal surface: the first region maintains strong adhesion for secure mounting and electrical connection, while the second region provides weaker adhesion that allows controlled peeling during vibration events, protecting the terminal from breakage
Solution Approach 2:
The lower adhesion second region acts as a pre-designed cushioning zone that absorbs vibration energy before it can transmit to the terminal body. This beforehand cushioning allows the terminal to withstand thermal stress-induced vibration without breaking while maintaining strong adhesion in critical connection areas
3Reliability
If the distance between conductive members is increased to ensure creeping distance, then electrical safety is improved, but the inductance increases
Solution Approach 1:
The adhesion surface is segmented into functional regions that allow the terminal to maintain compact positioning (low inductance) while the lower adhesion second region provides a controlled peeling mechanism that effectively increases the electrical clearance path without increasing the physical distance between terminals
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 configuration effectively prevents the external connection terminals from breaking during vibration while ensuring the creeping distance remains unchanged, enhancing the reliability and durability of the electronic device.
Implementation Method 1
a higher adhesion part having a higher adhesion to the sealing resin body, and a lower adhesion part having an adhesion to the sealing resin body which is lower than that of the higher adhesion part
Data Source
AI summary
An electronic device includes an electronic component, a sealing resin body, and a plurality of conductive members electrically connected to the electronic component in the sealing resin body, including respective portions exposed from the sealing resin body to the outside of the sealing resin body, and having different potentials. The conductive members include a heat sink and a terminal extending from an inside to the outside of the sealing resin body. A surface of the terminal includes, as a part covered with the sealing resin body, a higher adhesion part and a lower adhesion part. The lower adhesion part is provided in an entire portion of a back surface of the terminal, the back surface being opposite to a connection surface of the terminal which is adjacent to a connection part electrically connected to the electronic component. The higher adhesion part is provided in the connection surface.