skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules

Abstract

Cogenra’s Dense Cell Interconnect system was designed to use traditional front-contact cells and string them together into high efficiency and high reliability “supercells”. This novel stringer allows one to take advantage of the ~100 GW/year of existing cell production capacity and create a solar product for the customer that will produce more power and last longer than traditional PV products. The goal for this program was for Cogenra Solar to design and develop a first-of-kind automated solar manufacturing line that produces strings of overlapping cells or “supercells” based on Cogenra’s Dense Cell Interconnect (DCI) technology for their Low Concentration Photovoltaic (LCPV) systems. This will enable the commercialization of DCI technology to improve the efficiency, reliability and economics for their Low Concentration Photovoltaic systems. In this program, Cogenra Solar very successfully designed, developed, built, installed, and started up the ground-breaking manufacturing tools required to assemble supercells. Cogenra then successfully demonstrated operation of the integrated line at high yield and throughput far exceeding expectations. The development of a supercell production line represents a critical step toward a high volume and low cost Low Concentration Photovoltaic Module with Dense Cell Interconnect technology and has enabled the evaluation of the technology for reliability andmore » yield. Unfortunately, performance and cost headwinds on Low Concentration Photovoltaics systems including lack of diffuse capture (10-15% hit) and more expensive tracker requirements resulted in a move away from LCPV technology. Fortunately, the versatility of Dense Cell Interconnect technology allows for application to flat plate module technology as well and Cogenra has worked with the DOE to utilize the learning from this grant to commercialize DCI technology for the solar market through the on-going grant: Catalyzing PV Manufacturing in the US With Cogenra Solar’s Next-Generation Dense Cell Interconnect PV Module Manufacturing Technology. This program is now very successfully building off of this work and commercializing the technology to enable increased solar adoption.« less

Authors:
 [1]
  1. Cogenra Solar, Fremont, CA (United States)
Publication Date:
Research Org.:
Cogenra Solar, Fremont, CA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1413447
Report Number(s):
DOE-COGE-06812
DOE Contract Number:
EE0006812
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY

Citation Formats

Okawa, David. Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules. United States: N. p., 2017. Web. doi:10.2172/1413447.
Okawa, David. Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules. United States. doi:10.2172/1413447.
Okawa, David. 2017. "Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules". United States. doi:10.2172/1413447. https://www.osti.gov/servlets/purl/1413447.
@article{osti_1413447,
title = {Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules},
author = {Okawa, David},
abstractNote = {Cogenra’s Dense Cell Interconnect system was designed to use traditional front-contact cells and string them together into high efficiency and high reliability “supercells”. This novel stringer allows one to take advantage of the ~100 GW/year of existing cell production capacity and create a solar product for the customer that will produce more power and last longer than traditional PV products. The goal for this program was for Cogenra Solar to design and develop a first-of-kind automated solar manufacturing line that produces strings of overlapping cells or “supercells” based on Cogenra’s Dense Cell Interconnect (DCI) technology for their Low Concentration Photovoltaic (LCPV) systems. This will enable the commercialization of DCI technology to improve the efficiency, reliability and economics for their Low Concentration Photovoltaic systems. In this program, Cogenra Solar very successfully designed, developed, built, installed, and started up the ground-breaking manufacturing tools required to assemble supercells. Cogenra then successfully demonstrated operation of the integrated line at high yield and throughput far exceeding expectations. The development of a supercell production line represents a critical step toward a high volume and low cost Low Concentration Photovoltaic Module with Dense Cell Interconnect technology and has enabled the evaluation of the technology for reliability and yield. Unfortunately, performance and cost headwinds on Low Concentration Photovoltaics systems including lack of diffuse capture (10-15% hit) and more expensive tracker requirements resulted in a move away from LCPV technology. Fortunately, the versatility of Dense Cell Interconnect technology allows for application to flat plate module technology as well and Cogenra has worked with the DOE to utilize the learning from this grant to commercialize DCI technology for the solar market through the on-going grant: Catalyzing PV Manufacturing in the US With Cogenra Solar’s Next-Generation Dense Cell Interconnect PV Module Manufacturing Technology. This program is now very successfully building off of this work and commercializing the technology to enable increased solar adoption.},
doi = {10.2172/1413447},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Technical Report:

Save / Share:
  • As a result of this work, Evergreen Solar, Inc., is now poised to take String Ribbon technology to new heights. In the ribbon growth area, Project Gemini-the growth of dual ribbons from a single crucible-has reached or exceeded all the manufacturing goals set for it. This project grew from an R&D concept to a production pilot phase and finally to a full production phase, all within the span of this subcontract. A major aspect of the overall effort was the introduction of controls and instrumentation as in-line diagnostic tools. In the ribbon production area, the result has been a 12%more » increase in yields, a 10% increase in machine uptime, and the flattest ribbon ever grown at Evergreen. In the cell area, advances in process development and robotic handling of Gemini wafers have contributed, along with the advances in crystal growth, to a yield improvement of 6%. Particularly noteworthy in the cell area was the refinement of the no-etch process whereby the as-grown ribbon surface could be controlled sufficiently to allow this process to succeed as well as it has. This process obviates any need for wet chemistry or etching between ribbon growth and diffusion.« less
  • This report summarizes the work done under a three-year PVMaT Phase 5A2 program. The overall goal was to attain a continuous, highly automated, fully integrated PV production line. In crystal growth, advances were made that resulted in lower substrate costs, higher yields, and lower capital and labor costs. A new string material was developed and implemented. Following this development, better control of the edge meniscus was achieved. A completely new furnace design was accomplished, and this became the standard platform in our new factory. Automation included ribbon thickness control and laser cutting of String Ribbon strips. Characterization of Evergreen's Stringmore » Ribbon silicon was done with extensive help from the NREL laboratories, and this work provided a foundation for higher efficiency cells in the future. Advances in cell manufacturing included the development of high-speed printing and drying methods for Evergreen's unique cell making method and the design and building of a completely automated cell line from the beginning of front-contact application to the final tabbing of the cells. A so-called no-etch process whereby substrates from crystal growth go directly into p-n junction formation and emerge from this sequence without needing to go in and out of plastic carriers for any wet-chemical processing was developed. Process development as well as automation were brought to bear on improvements in soldering technology and cell interconnection in general. Using state-of-the-art manufacturing science, the Fraunhofer USA Center for Manufacturing Innovation at Boston University facilitated layout and process flow for the operation of our new factory. Evergreen Solar's new factory began operations in the second quarter of 2001. A good measure of the significant impact of this PVMaT subcontract is that virtually all of the manufacturing developments stemming from this project have been incorporated in this new factory.« less
  • SunPower Corp. describes its research to develop low-cost, next-generation SunPower modules with 30-year warranties and at least 50% higher energy production per area relative to today's typical multicrystalline Si modules.
  • The goal this project was to accelerate the deployment of innovative solar cell and module technologies that reduce the cost of PERC-based modules to best-in-class. New module integration technology was to be used to reduce the cost and reliance on conventional silver bus bar pastes and enhance cell efficiency. On the cell manufacturing front, the cost of PERC solar cells was to be reduced by introducing advanced metallization approaches to increase cell efficiency. These advancements will be combined with process optimization to target cell efficiencies in the range of 21 to 21.5%. This project will also explore the viability ofmore » a bifacial PERC solar cell design to enable cost savings through the use of thin silicon wafers. This project was terminated on 4/30/17 after four months of activity due financial challenges facing the recipient.« less
  • This report describes Evergreen Solar, Inc., String Ribbon Si PV technology resulting in an advanced generation of crystalline silicon PV module manufacturing technology applied to a virtually continuous, fully integrated manufacturing line. General objectives for this first year (or Phase I) are listed here, followed by the principal accomplishments for each of these objectives: (1) scale-up of a production-worthy method for doping feedstock; (2) development of a multiple-ribbon growth system (Project Gemini); (3) development of wrap-around contacts for making monolithic modules; (4) accelerated testing of small-size (25 W) monolithic modules; (5) development of an in-line production machine to form solarmore » cell contacts using Evergreen's unique contact printing technology.« less