Planar Busbar Assembly With Laser-Formed Openings for Insulation Reliability
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Solution Overview
Problem
Laminated-type busbar assemblies face challenges in ensuring reliable electric insulation due to thin insulating resin layers, which can lead to leakage currents and compromised connection strength, especially when trying to minimize size.
Innovation Solution
A busbar assembly with conductive flat plate busbars arranged in a common plane and an insulative resin layer that is transparent in a half-cured state and nontransparent in a completely cured state, featuring gap filling and surface laminate parts with center openings to prevent pinhole formation during laser machining, allowing for precise alignment and maintaining insulation and connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the insulating resin layer is made thin to downsize the busbar assembly, then the vertical size is reduced, but the electric insulation reliability deteriorates and leakage current may occur
Solution Approach 1:
The invention transitions from a vertical lamination structure to a planar arrangement where busbars are disposed in the same plane with gaps between them. This dimensional change allows the assembly to be downsized in the vertical direction while maintaining insulation reliability through the gap structure filled with insulative resin, preventing leakage current paths that would exist in thin vertical laminations.
Solution Approach 2:
The insulative resin is selectively applied to fill gaps between busbars at specific locations where electrical insulation is critical. The resin layer is configured to extend beyond the busbar edges in the width direction, providing enhanced local insulation coverage. This localized quality enhancement ensures reliable insulation without requiring a uniformly thick resin layer across the entire assembly, thus maintaining compact size while preventing leakage current.
2Manufacturing precision
If laser beam machining is performed to form openings in the insulative resin layer, then precise alignment and exposure regions are created, but pinholes may form in the gap filling part compromising insulation
Solution Approach 1:
The insulative resin layer is formed and cured to create a solid, pinhole-free base structure before laser beam machining is performed. By establishing the complete insulative resin layer with proper curing beforehand, the substrate is prepared in advance to resist pinhole formation during subsequent laser processing. The pre-formed resin structure provides a stable foundation that prevents harmful pinholes even when laser openings are created for component mounting.
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 enables the busbar assembly to maintain insulation properties and connection strength while minimizing size, preventing pinhole formation and allowing semiconductor elements to be mounted close to the gap without compromising insulation.
Implementation Method 1
Irradiating a laser beam to a center laser area including a first surface-side first center opening formation area corresponding to the first surface-side first center opening, a first surface-side second center opening formation area corresponding to the first surface-side second center opening, and an intermediate area sandwiched between the first surface-side first center opening formation area and the first surface-side second center opening formation area in a state that the insulative resin material provided on the entirety of the first surface of the busbar connection body is half-cured
Implementation Method 2
the insulative resin layer being formed by an insulative resin material that is transparent in a half-cured state and nontransparent in a completely cured state
Data Source
AI summary
A busbar assembly of the present invention includes a plurality of busbars disposed in parallel in a common plane with a gap between adjacent busbars, and an insulative resin layer including a gap filling part and a first surface-side laminate part, the first surface-side laminate part having a plurality of first surface-side center openings that expose predetermined parts of first surfaces of the plurality of busbars respectively to form a plurality of exposure regions, the insulative resin layer being formed by an insulative resin material that is transparent in a half-cured state and nontransparent in a completely cured state.