R.L. Mitchell

PVMaT advances in the photovoltaic industry and the focus of future PV manufacturing R&D

The DOE Photovoltaic Manufacturing Technology (PVMaT) Project has conducted cost-shared manufacturing R&D with the photovoltaic industry for over 10 years. During this time, research has focused on the projects stated objectives of improving photovoltaic manufacturing processes and products, lowering manufacturing costs, and providing a foundation for the scale-up of US photovoltaic (PV) manufacturing. Progress made by each of the US PV industry participants in this project has resulted in a significant reduction in the industrys direct PV module-manufacturing costs and an impressive scale-up in US PV manufacturing capacity. The majority of the efforts have been module related. Results in terms of automation, yield, and throughput have provided a significant reduction in direct manufacturing costs. Cost reductions and capacity increases resulting from these efforts are discussed.

Polycrystalline thin film photovoltaics

Significant progress has recently been made towards improving the efficiencies of polycrystalline thin-film solar cells and modules using CuInSe/sub 2/ and CdTe. The history of using CuInSe/sub 2/ and CdTe for solar cells is reviewed. Initial outdoor stability tests of modules are encouraging. Progress in semiconductor deposition techniques has also been substantial. Both CuInSe/sub 2/ and CdTe are positioned for commercialization during the 1990s. The major participants in developing these materials are described. The US DOE/SERI (Solar Energy Research Institute) program recognizes the rapid progress and important potential of polycrystalline thin films to meet ambitious cost and performance goals. US DOE/SERI is in the process of funding an initiative in this area with the goal of ensuring US leadership in the development of these technologies. The polycrystalline thin-film module development initiative, the modeling and stability of the devices, and health and safety issues are discussed.<<ETX>>

CuInSe2 and CdTe Scale-up for Manufacturing

Two candidate polycrystalline thin film materials, CuInSe2, and CdTe, have emerged as potential leaders in the effort to develop low-cost photovoltaics. Until recently, most progress in these materials was on a laboratory scale. For instance, small CuInSe2 cells have reached 14.1% (ARCO Solar), Photon Energy and Ametek have achieved 12.3% and 11% efficiencies for CdTe. However, both technologies are now moving toward commercial products and are being developed for power modules. Issues relating to their scale-up to manufacturing are increasingly germane.

Status of the photovoltaic manufacturing technology (PVMaT) project

The PVMaT Project and the work carried out under its Phase 1 are described. Phase 1 subcontracted research included silicon technology, ten on flat-plate thin film modules (one on thin films crystalline silicon, five on amorphous silicon, and four on polycrystalline thin films), six on concentrator systems, and two working on general equipment/production options. A brief discussion of the second and third phases is also presented.<<ETX>>

POLYCRYSTALLINE THIN FILM PHOTOVOLTAIC TECHNOLOGY

Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and thin-film CdTe solar cells. NCPV/NREL scientists have achieved world-record, total-area efficiencies of 19.3% for a thin-film CIGS solar cell and 16.5% for thin-film CdTe solar cell. A number of technical R&D issues related to CIS and CdTe have been identified. Thin-film power module efficiencies up to 13.4% has been achieved thus far. Tremendous progress has been made in the technology development for module fabrication, and multi-megawatt manufacturing facilities are coming on line with expansion plans in the next few years. Several 40-480 kW polycrystalline thin-film, grid-connected PV arrays have been deployed worldwide. Hot and humid testing is also under way to validate the long-term reliability of these emerging thin-film power products. The U.S. thin-film production (amorphous silicon[a-Si], CIS, CdTe) is expected to exceed 50 MW by the end of 2005.Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and thin-film CdTe solar cells. NCPV/NREL scientists have achieved world-record, total-area efficiencies of 19.3% for a thin-film CIGS solar cell and 16.5% for thin-film CdTe solar cell. A number of technical R&D issues related to CIS and CdTe have been identified. Thin-film power module efficiencies up to 13.4% has been achieved thus far. Tremendous progress has been made in the technology development for module fabrication, and multi-megawatt manufacturing facilities are coming on line with expansion plans in the next few years. Several 40-480 kW polycrystalline thin-film, grid-connected PV arrays have been deployed worldwide. Hot and humid testing is also under way to validate the long-term reliability of these emerging thin-film power products. The U.S. thin-film production (amorphous silicon[a-Si], CIS, CdTe) is expected to exceed 50 MW by the end of 2005.

The DOE/SERI polycrystalline thin film subcontract program

The authors give a summary of the status of polycrystalline thin film solar cells. The requirements for them to meet the Department of Energy (DOE) cost-competitive goals, program highlights, research issues, manufacturability, and future plans are presented. A table showing funding for polycrystalline thin films is also given.<<ETX>>

Benefits from the US photovoltaic manufacturing technology project

This paper examines the goals of the Photovoltaic Manufacturing Technology (PVMaT) project and its achievements in recapturing the investment by the photovoltaic (PV) industry and the public in this research. The PVMaT project was initiated in 1990 with the goal of enhancing the worldwide competitiveness of the US PV industry. Based on the authors analysis, PVMaT has contributed to PV module manufacturing process improvements, increased product value and reductions in the price of todays PV products. An evaluation of success in this project was conducted using data collected from 10 of the PVMaT industrial participants in late fiscal year (FY) 1995. These data indicate a reduction of 56% in the weighted average module manufacturing costs from 1992 to 1996. During this same period, US module manufacturing capacity has increased by more than a factor of 6. Finally, the analysis indicates that both the public and the manufacturers will recapture the funds expended in R&D manufacturing improvements well before the year 2000.

Recent progress in the Photovoltaic Manufacturing Technology Project (PVMaT)

The Photovoltaic Manufacturing Technology (PVMaT) Project was initiated in 1990 to help the US photovoltaic (PV) industry extend its world leadership role in manufacturing and commercially developing PV modules and systems. It is being conducted in several phases, staggered to support industry progress. The four most recently awarded subcontracts (Phase 2B) are now completing their first year of research. They include two subcontracts in CdTe, one on spheral solar cells, and one on cast polysilicon. These subcontracts represent new technology additions to the PVMaT Project. Subcontracts initiated in earlier phases are nearing completion, and their progress is summarized. An additional phase of PVMaT, Phase 4A, is being initiated which will emphasize product-driven manufacturing research and development. The intention of Phase 4A is to emphasize improvement and cost reduction in the manufacture of full-system PV products. The work areas may include, but not limited to, issues such as: improvement of module manufacturing processes; system and system component packaging, integration, manufacturing, and assembly; product manufacturing flexibility; and balance-of-system development with the goal of product manufacturing improvements.

Progress in phases 2 and 3 of the Photovoltaic Manufacturing Technology project (PVMAT)

The first year of the process-specific activities of the Photovoltaic Manufacturing Technology (PVMaT) project has been completed, and the first subcontracts for teamed efforts on R&D of a general nature have been awarded. A second solicitation for process-specific research and development (R&D) is in the evaluation stage for award of subcontracts. This paper describes the technical accomplishments of the first process-specific subcontracts (Phase 2A), the status of the teamed research (Phase 3A), and the status of the solicitation for the second process-specific solicitation (Phases 2B).<<ETX>>

Decade of PV industry R&D advances in silicon module manufacturing

The US photovoltaic (PV) industry has made significant technical advances in crystalline silicon (Si) module manufacturing through the PV Manufacturing R&D Project during the past decade. Funded Si technologies in this project have been Czochralski, cast polycrystalline, edge-defined film fed growth (EFG) ribbon, string ribbon, and Si-film. Specific R&D Si module-manufacturing categories that have shown technical growth and are discussed are in crystal growth and processing, wafering, cell fabrication, and module manufacturing. These R&D advancements since 1992 have contributed to a 30% decrease in PV manufacturing costs and stimulated a sevenfold increase in PV production capacity.