Photovoltaic Modules

About

Technology This innovation is a high throughput thin film device manufacturing process that produces stable, high efficiency devices and, at the same time, limits environmental and occupational exposure to toxic compounds. The technology consists of a comprehensive apparatus and system for large scale inline manufacturing of CdTe photovoltaic modules in which all steps are performed within a single vacuum boundary at modest vacuum pressures. Manufacturing steps performed by the apparatus include rapid substrate heating and cooling, deposition of CdS, deposition of CdTe, CdC12 treatment, and ohmic contact formation. The system also includes formation of a back electrode via a low cost spray process and module scribing by means of abrasive blasting or mechanical brushing through a mask. A sophisticated module conveyance system transports modules into and out of the vacuum environment. Multiple advantages accrue as a result of performing all manufacturing steps within a vacuum. Selective heating of substrates and films, exposure of substrates and films to vapor with minimal vapor leakage, deposition of thin films onto a substrate, and stripping thin films from a substrate are all facilitated by the vacuum environment. Furthermore, by utilizing inline vacuum processing to form all of the critical layers without breaking vacuum, an improvement in process throughput, film quality, device efficiency, and device stability is realized, while at the same time avoiding pinhole formation. Having all processing under vacuum is also advantageous in that it limits the production of toxic waste and environmental and occupational exposure to toxic compounds. This innovation is part of a large portfolio of thin film technologies specifically developed for CdTe photovoltaic devices but potentially applicable to a wide variety of thin film technologies. Thin film coated substrates are ubiquitous in today's society and have been used for numerous aspects of consumer electronics (from integrated circuit fabrication to cell phone, computer and television display coatings), optics (e.g., coating glass), microparticle fabrication, photovoltaic fabrication, and packaging (e.g., aluminum coating on plastic for potato chip bags).