Nested V-Shaped Interconnects for PV Thermal Stress Relief
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Solution Overview
Problem
Photovoltaic systems face stress due to temperature differences and varying thermal expansion coefficients of materials, which existing electrical interconnects struggle to accommodate effectively, often requiring complex and costly manufacturing processes.
Innovation Solution
The development of electrical interconnects with a continuous central portion and angled legs, featuring gaps between legs to allow for in-plane and out-of-plane flexing, enabling relative motion between photovoltaic cells and metalized substrates, thus reducing stress and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical interconnects use complex shapes with out-of-plane features to accommodate thermal expansion, then stress relief capability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The interconnect is segmented into multiple planar layers with through-traces that create flexible zones. The through-traces act as hinges allowing relative movement between layers, providing stress relief without requiring complex out-of-plane features. This segmentation approach maintains manufacturing simplicity while achieving the desired flexibility.
Solution Approach 2:
The invention transitions from traditional single-plane interconnects to multi-layer stacked structures. By adding the vertical dimension with multiple planar layers connected by through-traces, the design achieves out-of-plane flexibility while maintaining planar manufacturing processes. The through-traces enable bending and flexing in the vertical direction without requiring complex 3D shaping.
2Reliability
If enclosed voids are added to interconnects to accommodate thermal expansion, then stress relief capability is improved, but manufacturing complexity increases due to additional cutting steps
Solution Approach 1:
Instead of creating enclosed voids within single layers, the structure is segmented into multiple layers with strategic gaps between corresponding features. The through-traces connect these layers, creating a flexible stacked structure that accommodates thermal expansion without requiring void cutting operations. This approach achieves stress relief through layer separation rather than material removal.
Solution Approach 2:
The multi-layer structure with gaps between layers creates a porous-like configuration that allows for thermal expansion accommodation. The through-traces provide structural connectivity while the gaps between layers enable flexing and stress relief, mimicking the benefits of porous structures without requiring actual void formation through complex cutting processes.
3Ease of manufacture
If traditional rigid interconnects are used, then manufacturing simplicity is maintained, but stress relief capability deteriorates under temperature cycling
Solution Approach 1:
The interconnect structure transitions from rigid to dynamically flexible through the multi-layer stacked design with through-traces. The through-traces act as flexible hinges that allow the layers to move relative to each other under thermal stress, providing dynamic stress relief. This maintains manufacturing simplicity by using standard planar fabrication processes while achieving the reliability benefits of flexible interconnects.
Solution Approach 2:
Each layer in the stacked structure functions as a flexible thin film that can bend and deform to accommodate thermal expansion. The through-traces connect these flexible films while allowing relative movement, creating a structure that combines the manufacturing simplicity of thin-film deposition with the stress relief capabilities of flexible interconnects. This approach avoids the need for complex rigid structures while maintaining ease of manufacture.
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
These interconnects provide stress relief, maintain high current carrying capacity, reduce manufacturing costs, and allow for repeated temperature cycling without failure, while avoiding efficiency-reducing reflections and simplifying the manufacturing process.
Implementation Method 1
These temperature differences and differences in thermal expansion coefficients of materials used in the photovoltaic system may apply significant stress to the electrical interconnect, the photovoltaic cells, and the metalized substrate.
Implementation Method 2
The gaps enable movement of the first set of connector pads relative to the second set of connector pads
Data Source
AI summary
A method including forming an interconnect in a metal member. The interconnect includes multiple repeating, nested V-shaped structures forming a continuous central portion. A vertex of each of the multiple repeating, nested V-shaped structures adjoins a next vertex of a next V-shaped structure of the multiple repeating, nested V-shaped structures. The method further includes separating the interconnect from the metal member.