Automated assembly and mounting of solar cells on space panels

Patent metadata

Field	Value
Publication number	US-2016359079-A1
Application number	US-201615170269-A
Country	US
Kind code	A1
Filing date	Jun 1, 2016
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

The present disclosure provides methods of fabricating a multijunction solar cell panel in which one or more of the steps are performed using an automated process. In some embodiments, the automated process uses machine vision.

First claim

1 . A method of fabricating a multijunction solar cell array panel comprising one or more of the steps of:
fabricating a wafer utilizing a metal organic chemical vapor deposition (MOCVD) reactor; metallizing the backside of the wafer; lithographically patterning and depositing metal of the front side of the wafer; forming a mesa on the front side of the wafer by lithography and etching; depositing an antireflective coating (ARC) over the wafer; dicing one or more solar cells from the wafer; testing the functionality of the one or more solar cells; attaching interconnects to the one of more solar cells, wherein one of the interconnects is welded to a bottom metal contact layer of the one of more solar cells; attaching a cover glass to each solar cell to form a Cell-Interconnect-Cover Glass (CIC); forming a string configuration of CICs; interconnecting string configurations of CICs; bonding string configurations or interconnected string configurations to a substrate; configuring and wiring a panel circuit; configuring a blocking diode; wiring a first terminal and a second terminal of first and second polarities, respectively, for the solar cell panel; and testing the functionality of the solar cell panel; wherein at least one of the method steps is performed using an automated process.

2 . The method of claim 1 wherein the automated process uses machine vision.

3 . The method of claim 1 wherein at least one of the automated processes uses a robot.

4 . The method of claim 1 wherein at least one of the automated processes uses a pick and place assembly tool; a wire bonding machine or a laser welding machine for attaching interconnects to one or more solar cells; automatic vapor deposition equipment; automatic metal plating equipment; automatic lithographic techniques; automatic etching techniques; automatic dicing techniques; automatic testing equipment; automatic soldering or laser welding equipment; automatic dispensing equipment; automated wiring equipment; and/or automatic application of pressure and/or heat.

5 . The method of claim 1 wherein the solar cells each have a surface area of less than 5 cm 2 .

6 . The method of claim 1 wherein the solar cells are III-V compound semiconductor multijunction solar cells, and fabricating the wafer comprises:
providing a metal organic chemical vapor deposition (MOCVD) system configured to independently control the flow of source gases for gallium, indium aluminum, and arsenic;
selecting a reaction time and temperature and a flow rate for each source gas to form the continuously-graded interlayer disposed on the bottom subcell,
wherein the source gas for indium is trimethylindium (InMe 3 ), the sources gas for gallium in trimethylgallium (GaMe 3 ), the source gas for arsenic is arsine (AsH 3 ), and the source gas for aluminum is trimethylaluminum (Al 2 Me 6 ).

7 . The method of claim 1 wherein the panel is flexible and is composed of a poly(4,4′-oxydiphenylene-pyromellitimide) material.

8 . The method of claim 1 wherein the step of fabricating a wafer comprises:
providing a first substrate;
depositing on the first substrate a sequence of layers of semiconductor material forming at least first, second, and third solar cells;
forming a grading interlayer on said first, second, and/or said third solar cell;
depositing on said grading interlayer a second sequence of layers of semiconductor material forming a fourth solar cell, the fourth solar cell lattice mismatched to the third solar cell;
mounting and boding a surrogate substrate on top of the sequence of layers; and
removing the first substrate, wherein forming the graded itnterlayer comprises:
picking an interlayer composed of InGaAlAs;
using a computer program to identify a set of compositions of the formula (In x Ga 1-x ) y Al 1-y As defined by specific values of x and y, wherein 0<x<1 and 0<y<1, each composition having a constant bandgap;
identifying a lattice constant for one side of the graded interlayer that matches the middle subcell and a lattice constant for an opposing side of the interlayer that matches the bottom subcell; and
identifying a subset of compositions of the formula (In x Ga 1-x ) y Al 1-y As having the constant bandgap that are defined by specific values of x and y, wherein 0<x<1 and 0<y<1, and wherein the subset of compositions have lattice constants ranging from the identified lattice constant that matches the adjacent subcell to the identified lattice constant that matches the bottom subcell.

9 . A method of fabricating a multijunction solar cell array on a carrier using one or more automated processes, the method comprising:
providing a first multijunction solar cell including a first contact pad disposed adjacent the top surface of the multijunction solar cell along a first peripheral edge thereof; attaching a first electrical interconnect to the first contact pad of said first multijunction solar cell; welding attaching a second electrical interconnect to a second contact pad disposed adjacent a bottom metal contact layer and along the first peripheral edge of the first multijunction solar cell; positioning said first multijunction solar cell over an adhesive region of a permanent carrier using an automated machine/vision apparatus; mounting a cover glass over said first multijunction solar cell; and bonding said first multijunction solar cell to said adhesive region using pressure and/or heat.

10 . The method of claim 9 wherein at least one of the automated processes uses machine vision.

11 . The method of claim 9 wherein at least one of the automated processes uses a robot.

12 . The method of claim 9 wherein at least one of the automated processes uses a pick and place assembly tool; a wire bonding machine or a laser welding machine for attaching interconnects to one or more solar cells; automatic vapor deposition equipment; automatic metal plating equipment; automatic lithographic techniques; automatic etching techniques; automatic dicing techniques; automatic testing equipment; automatic soldering or laser welding equipment; automatic dispensing equipment; automated wiring equipment; and/or automatic application of pressure and/or heat.

13 . The method of claim 9 wherein the solar cell is a III-V compound semiconductor multijunction solar cell prepared from a fabricated wafer, and fabricating the wafer comprises:
providing a metal organic chemical vapor deposition (MOCVD) system configured to independently control the flow of source gases for gallium, indium aluminum, and arsenic;
selecting a reaction time and temperature and a flow rate for each source gas to form the continuously-graded interlayer disposed on the bottom subcell,
wherein the source gas for indium is trimethylindium (InMe 3 ), the sources gas for gallium in trimethylgallium (GaMe 3 ), the source gas for arsenic is arsine (AsH 3 ), and the source gas for aluminum is trimethylaluminum (Al 2 Me 6 ).

14 . The method of claim 9 wherein the panel is flexible and is composed of a poly(4,4′-oxydiphenylene-pyromellitimide) material.

15 . The method of claim 9 wherein the solar cell is a III-V compound semiconductor multijunction solar cell prepared from a fabricated wafer, and fabricating the wafer comprises:
providing a first substrate;
depositing on the first substrate a sequence of layers of semiconductor material forming at least first, second, and third solar cells;
forming a grading interlayer on said first, second, and/or said third solar cell;
depositing on said grading interlayer a second sequence of layers of semiconductor material forming a

Assignees

• Solaero Tech Corp

Inventors

• Clevenger Marvin Bradford
• Richards Benjamin C
• Tourino Cory
• Yang Lei
• Aiken Daniel
• Derkacs Daniel
• Blumenfeld Philip E

Classifications

• H10P74/207

  Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics · CPC title

• Y02E10/544

  Solar cells from Group III-V materials · CPC title

• H01L31/0508

  Electricity · mapped topic

• H01L31/0443

  Electricity · mapped topic

• H01L31/0516

  Electricity · mapped topic