Champion Companies of Photovoltaics

Solar Frontier: Big-time CIS in Japan

Solar Frontier’s Kunitomi Plant is Japan’s largest solar module production facility, as well as the largest CIS factory in the world. With Solar Frontier’s existing plants, the company now has a total annual production capacity of around 1 gigawatt. The billion-dollar plant shipped its first commercial thin-film CIS solar modules in February, 2011, only 16 months after breaking ground.

“The Atsugi Research Center (ARC) functioned as a production laboratory where we were able to fine-tune processes from raw materials to finished modules until our modeling matched precisely what we wanted to see in production,” said Satoru Kuriyagawa, Solar Frontier’s Chief Technology Officer. “We increased the efficiency of the factory with ten-fold scale over Plant 2, added extensive automation while also increasing the size and efficiency of the modules coming off the Kunitomi production line.”

Solar Frontier says its modules are able to deliver higher overall power output (kWh) under real weather conditions. In operating conditions, the “light soaking” effect of CIS modules significantly increases output from initial values, while a lower temperature coefficient than crystalline silicon modules means more kWh produced under real conditions in a wide range of climates.

“We identified CIS thin-film technology in 1993 as having the greatest potential to succeed the maturing crystalline silicon standard. Successfully ramping up from breaking ground to gigawatt-scale production in just over 21 months demonstrates the comprehensive abilities of Solar Frontier,” said Shigeaki Kameda, CEO. “Not only are we proving the compelling features of our next-generation CIS modules though strong support from our customers, we have also now shown the world that we can scale this technology at speed.”

JinkoSolar: A quantum leap

JinkoSolar Holding Co., Ltd. recently announced commercial-scale production of its Q-1 Solar Modules, part of the Quantum Series. These modules are produced using pseudo-mono multi-crystalline cells, which combine the benefits of mono- and multi-crystalline cells to better align the crystalline structure and achieve a higher efficiency product, all while maintaining low production costs. The cells deployed currently perform at an 18.3% efficiency level. The Quantum-1 modules, with an array of 60 solar cells, can perform up to 250 Wp.

JinkoSolar has an integrated annual capacity of 900 MW each for silicon ingots, silicon wafers, solar cells and solar modules, and plans to expand its annual capacity to 1.5 GW each for silicon wafers, solar cells and solar modules by end of 2011.

When the new R&D center was announced in early 2011, JinkoSolar said it wanted to increase the conversion efficiency rate to more than 18.6 percent for monocrystalline solar cells and more than 17.5 percent for multicrystalline solar cells by the end of 2011. “We launched our new research and development center to focus on improving the conversion efficiency of our solar cells and next generation photovoltaic technologies,” said Xiande Li, Chairman of JinkoSolar. The company also recently announced a 10-year product warranty for Quantum-1 Modules, with the option for a positive tolerance of up to 0.3 percentin addition to an optional Linear Performance Warranty.

Roth & Rau: 20 percent output efficiency on 156mm wafers

The research line at Roth & Rau Switzerland AG has achieved an impressive cell output efficiency rate of 20 percent using 156mm industrial monocrystalline silicon wafers. How? Using heterojunction technology. Similar results were achived at the company’s pilot line in Hohenstein-Ernstthal, Germany, where the processes are already being scaled up for mass production. “The high level of output efficiency offered by heterojunction technology, combined with its excellent temperature coefficients (>5 percent additional energy yield per module), address the key cost factors in the photovoltaics market,” said Dr. Dietmar Roth, CEO of Roth & Rau AG.

The silicon heterojunction cells offer excellent surface passivation provided by H and extra band bending -- due to the larger band gap of a-Si:H compared to c-Si -- makes well-designed a-Si:H emitters superior to conventional emitters made by dopant diffusion. Furthermore, a thin layer of a-Si:H, doped the same as the base wafer provides a back collector with very effective back-surface field that reduces the recombination velocity.

The company has been developing high-efficiency solar cells based on heterojunction technology since May 2008. The latest achievement is the result of a joint development effort with EPFL/IMT at the Université de Neuchâtel. The two parties worked together to transfer the results of the Institute’s research then available into industrial processes and to systematically enhance these results.

Ferro: Focused on materials

While Ferro has become a leading supplier of materials to the thick film photovoltaics industry, Ferro knows widespread photovoltaic power generation will occur once grid parity is achieved and exceeded for all PV systems. The PV industry has long-recognized the dramatic effect that long-term outdoor exposure to harsh environments has had on module performance and lifetime. Because module failures and performance losses are the result of gradual accumulated degradation and corrosion, researchers at Ferro ECGM have spent much of the past year working to revolutionize solar module durability by taking the harsh environment out of the equation.

Ferro has recently commenced several large-scale projects to develop and commercialize materials that will strengthen solar modules at lower costs, thereby significantly reducing the Levelized Cost of Energy (LCOE). Ferro is currently partnering with Edison Welding Institute, StrateNexus Technologies, and The Ohio State University to develop and commercialize advanced durability sealing systems for solar cells. In this project, Ferro is engineering a vitreous frit system to provide reliable air-tight and water-tight seals for second and third generation thin-film solar cells. Ferro is also in the early stages of a project that will drastically improve encapsulation systems by developing and commercializing a high performance glass filled barrier coating. This coating will not only strengthen solar modules, but it will increase throughput by requiring less capital and less labor intensive methods.