Bus Bar Module Structure to Reduce Spacer Warpage
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Solution Overview
Problem
Conventional bus bar modules experience insulation deterioration due to thermal expansion coefficient differences between bus bars and spacers, leading to warpage and cracking, which compromises insulation performance.
Innovation Solution
A bus bar module design featuring bus bars with holes and a spacer with overlapping holes, filled with encapsulation resin, to reduce stress on the spacer and enhance adhesion to the resin mold, thereby minimizing warpage and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bus bar and spacer are entirely encapsulated with insulating resin through insert molding, then insulation performance is improved, but warpage occurs due to thermal expansion coefficient difference between bus bar and spacer
Solution Approach 1:
The contact face between the bus bar and spacer is divided into two regions: a first region where the bus bar and spacer are adhered together, and a second region where they are not adhered. This segmentation allows the adhered first region to provide thermal expansion compensation and prevent warpage, while the non-adhered second region maintains insulation performance through resin encapsulation.
Solution Approach 2:
Different regions of the contact face are given different properties: the first region has adhesion property to compensate for thermal expansion differences, while the second region has insulation property through resin encapsulation. This local differentiation resolves the contradiction between preventing warpage and maintaining insulation.
2Reliability
If the area of parallel planar region of bus bars is increased to reduce interconnection inductance, then the length of non-adhered region increases, causing increased warpage
Solution Approach 1:
The contact face is segmented into adhered and non-adhered regions, allowing the bus bar structure to maintain large parallel planar areas for low inductance while the adhered first region provides localized thermal expansion compensation to control warpage despite the increased size of the overall structure.
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 solution effectively suppresses insulation property deterioration, improves reliability, and enhances quake resistance by reducing warpage and stress concentration, while maintaining large parallel planar areas for reduced interconnection inductance.
Implementation Method 1
the resin mold is adhered to each of the bus bar 1a, the bus bar 1b and the spacer 2 even in the through-hole 20H
Implementation Method 2
Since a difference in thermal expansion coefficient between the bus bar and the spacer is large, when the conventional bus bar module is exposed in high and low temperature environments, in the bus bar not joined to the spacer, warpage may occur due to a thermal strain difference between them caused by the temperature change
Data Source
AI summary
An object herein is to provide a bus bar module which is highly reliable in insulation performance, by reducing stresses imposed on its spacer to thereby suppress deterioration in the insulation property thereof. The bus bar module includes: a bus bar having a hole in its parallel planar region and made of an electrically conductive material; a bus bar opposed to the bus bar, having a hole in its parallel planar region and at a position corresponding to the hole, and made of an electrically conductive material; a spacer made of an insulating material, which is sandwiched between the bus bars, and in which a hole is provided so as to overlap with the hole and the hole; and a resin mold covering these bus bars and the spacer; wherein a through-hole that is established by the holes, is filled with a portion of the resin mold.