Back Contact Solar Cell Arrays for Space
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Solution Overview
Problem
Conventional space solar array panels face challenges in achieving high packing density and efficient interconnection of solar cells due to the need for manual labor and labor-intensive processes, which increase costs, weight, and reduce performance.
Innovation Solution
The development of a solar cell array design with all backside contacts and integral interconnections on a supporting substrate, utilizing discrete conductive semiconductor elements and stand-off components to enable automated assembly and increased packing density, reducing the need for manual labor and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional solar cells are densely packed on rigid supporting panels with manual interconnection, then solar cell coverage area is maximized, but manufacturing complexity and labor intensity increase significantly
Solution Approach 1:
The solar cell array is segmented into modular units with standardized backside contacts, allowing automated assembly. Each solar cell is divided into functional regions (light-receiving surface with grid lines, back surface with contacts) that can be independently processed and then automatically interconnected, reducing overall system complexity.
Solution Approach 2:
Manual mechanical interconnection processes are replaced with automated welding or soldering systems. The interconnect components are designed to facilitate automated attachment to backside contacts, substituting labor-intensive manual operations with automated mechanical and thermal processes.
2Adaptability or versatility
If manual labor is used for interconnecting solar cells and mounting on panels, then interconnection flexibility is maintained, but manufacturing cost and time increase
Solution Approach 1:
The backside contact design serves multiple functions: electrical connection, mechanical support, and alignment reference for automated assembly. The interconnect components are designed with universal attachment methods that work across different solar cell configurations, enabling automated processing while maintaining design flexibility.
Solution Approach 2:
The invention changes the contact configuration parameter from conventional front-side or mixed contacts to all-backside contacts. This parameter change enables automated pick-and-place assembly and simplifies the interconnection geometry, allowing high-speed automated manufacturing while maintaining electrical performance.
3Reliability
If discrete metal interconnect elements are used between solar cells, then electrical connection is achieved, but packing density decreases due to spatial requirements
Solution Approach 1:
The interconnect elements are nested within the cropped corner regions of solar cells, utilizing otherwise wasted space. The interconnects are positioned in the corners and extend along the edges, nesting the electrical connection path within the cell boundary rather than requiring additional external space.
Solution Approach 2:
The electrical connection transitions from a planar arrangement to a three-dimensional configuration using the vertical dimension. Interconnect elements extend from the back surface through or beyond the cell thickness, utilizing the Z-dimension to establish electrical connections without occupying additional planar area.
4Strength
If conventional solar cell assemblies are manufactured with individual welding and mounting steps, then connection strength is ensured, but manufacturing time and labor costs increase
Solution Approach 1:
Interconnect components are pre-attached to solar cells in a preliminary manufacturing step before final array assembly. This preliminary action allows optimization of the attachment process under controlled conditions and enables parallel processing, reducing the overall manufacturing cycle time while maintaining connection strength.
Solution Approach 2:
Multiple manufacturing steps are merged into integrated processes. The attachment of interconnects to solar cells is combined with the mounting process on supporting substrates, and electrical interconnection is combined with mechanical attachment, reducing the total number of discrete steps and overall manufacturing time.
Data Source
AI summary
A back contact solar cell assembly and methods for its manufacture and assembly onto a panel for use in space vehicles are described. The solar cell assembly includes a compound semiconductor multijunction solar cell having a contact at the top surface of the solar cell, a conductive semiconductor element extending from the contact on the top surface to the back surface of the assembly where it forms a first hack contact of a first polarity type, and a second back contact of a second polarity at the back surface of the assembly electrically coupled to the back surface of the solar cell.