Flexible Membrane Solar Generator with Heat Welded Photovoltaic Units
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Solution Overview
Problem
Existing solar generator systems for satellites face challenges in achieving high power density and low on-board mass due to rigid panels and adhesives, which are costly, complex, and add mass, while also failing to provide optimal mechanical, electrical, and thermal performance.
Innovation Solution
A flexible membrane with a main substrate and photovoltaic units connected via heat welding using thermoplastic polymers, eliminating the need for adhesives and allowing for a compact, high-power solar generator with improved mechanical, electrical, and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid panels with articulation are used for solar generators, then structural strength and stability are improved, but on-board mass increases and power density decreases
Solution Approach 1:
The patent replaces rigid solar panels with flexible membranes that can be wound during launch and deployed in orbit. The membrane incorporates photovoltaic cells integrated into a flexible substrate with reinforcing elements, eliminating the need for heavy rigid structures while maintaining structural integrity during deployment and operation.
Solution Approach 2:
The solar generator transitions from a static rigid structure to a dynamic system that can change configuration - wound into a compact form during launch and deployed to a large surface area in orbit. This dynamic capability allows the same structure to meet both launch constraints and operational power requirements.
2Strength
If structural adhesive is used to assemble photovoltaic cells on substrate, then bonding strength is improved, but manufacturing time and cost increase due to polymerization requirements
Solution Approach 1:
The patent replaces chemical bonding (adhesive polymerization) with mechanical bonding through friction stir welding. This process mechanically interlocks the substrate and photovoltaic cell assemblies, eliminating the need for chemical adhesives and their associated polymerization times while maintaining strong bonding.
3Ease of manufacture
If double-sided adhesive is used for assembly, then implementation complexity is reduced, but bonding strength and radiation resistance decrease
Solution Approach 1:
The patent replaces adhesive bonding with friction stir welding, which provides superior bonding strength and radiation resistance. The mechanical interlocking created by the friction stir welding process maintains integrity under the extreme conditions of space radiation and thermal cycling, unlike adhesive bonds.
4Ease of manufacture
If adhesive bonding or mechanical fastening is used, then assembly is simplified, but thermal conductivity between elements decreases
Solution Approach 1:
The patent replaces adhesive or mechanical fastening with friction stir welding, which creates direct metal-to-metal contact between the substrate and photovoltaic cell assemblies. This direct contact maintains high thermal conductivity, enabling effective heat dissipation from the photovoltaic cells without the thermal barrier introduced by adhesives or fasteners.
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 a compact, high-power solar generator with reduced mass, enhanced mechanical and thermal performance, and simplified assembly and repair, while maintaining electrical efficiency and thermal conductivity.
Implementation Method 1
The lower surface of the secondary substrate of the photovoltaic unit and the upper surface of the main substrate being at least partially heat welded
Data Source
AI summary
A membrane capable of passing from a configuration wound about a first axis Z to a configuration deployed along a second axis X substantially perpendicular to the first axis Z, includes a. a main substrate comprising an upper surface covered at least partially with a first layer comprising a first thermoplastic polymer, b. at least one electrically conductive track, c. a photovoltaic unit comprising a secondary substrate and at least one photovoltaic cell fixed to an upper surface of the secondary substrate, the photovoltaic unit being designed to produce an electric current, and being electrically connected to the at least one electrically conductive track, the secondary substrate comprising a lower surface, opposite the upper surface of the secondary substrate and oriented towards the upper surface of the main substrate, the lower surface of the secondary substrate being covered at least partially with a second layer comprising a second thermoplastic polymer, the lower surface of the secondary substrate of the photovoltaic unit and the upper surface of the main substrate being at least partially heat welded.