A number of "tandem-type" amorphous silicon thin film solar panels were exhibited at PV Japan 2009, an exhibition of photovoltaic technologies that is running from June 24 to 26, 2009, at Makuhari Messe in Chiba Prefecture, Japan.
A tandem-type panel consists of different kinds of solar cells and can convert light in a wider wavelength range to electricity. The exhibited tandem-type panels were composed of amorphous silicon and microcrystalline silicon and expected to be used for industrial photovoltaic systems.
AMAT displays large tandem-type panel
The tandem-type solar panels were showcased by Applied Materials Inc (AMAT) of the US, Ulvac Inc, Oerlikon Solar Ltd of Switzerland, Sharp Corp, Sanyo Electric Co Ltd and so forth. AMAT, Ulvac and Oerlikon Solar, which prepare entire production lines and sell them as "turnkey solutions," are actively competing against one another in price and performance.
This time, AMAT showed off a tandem-type thin film solar panel using an 8.5-generation, 5.7m2 glass plate.
"We developed the manufacturing equipment long ago, but it took long to get certification from IEC (International Electrotechnical Commission) because the panel is so large," AMAT said. "We aim to increase the module conversion efficiency after stabilization (from 8%) to 10% and achieve the grid parity* with a cost of $1/W in 2010."
*Grid parity here means that solar power generation cost is equal to the cost of grid electricity.
Ulvac claims advantages in performance, cost
Meanwhile, Ulvac announced June 23, 2009, the "CIM-1400," plasma CVD equipment for tandem-type solar panels. When the equipment is added to an existing production line for thin-film solar cells, it enables the line to manufacture tandem-type panels. The panel exhibited by the company was produced with this method.
"Unijunction panels look reddish, but tandem-type panels are blackish so that it can use light in a wider wavelength range," Ulvac said.
The panel measures 1.1 x 1.4m and has a conversion efficiency of 9% or more in the aperture area.
Ulvac fell behind AMAT and Oerlikon Solar in announcing the production of tandem-type panels but claims that it has advantages over its competitors in takt time, uniformity in film formation and yield.
Oerlikon takes lead in delivery record
Oerlikon Solar's panel was exhibited at the booth of Tokyo Electron Ltd, with which Oerlikon Solar announced a marketing alliance in the Asia and Oceania regions in February 2009.
"Oerlikon Solar's production equipment has already produced about 900,000 pieces of unijunction panels, which is more than double the numbers at other companies," Tokyo Electron said. "Also, Auria Solar Co Ltd of Taiwan started to mass-produce tandem-type panels, and a few firms are following it."
The size of its panel is 1.1 x 1.3m, which is slightly smaller than the panels of other manufacturers. But Oerlikon Solar plans to further improve the performance and reduce the cost in prospect of achieving a conversion efficiency of 9.3% by the fourth quarter of 2010.
Oerlikon Solar announced a tandem-type panel with a conversion efficiency of 11% in May 2009.
"It is an efficiency before stabilization, and it is expected to become 9.1 to 9.3% after stabilization," Tokyo Electron said.
Japanese manufacturers set to roll solar panels
Sharp, which manufactures solar panels in house, displayed a tandem-type thin film solar panel that is 1,409 x1,009mm in size. It features a module conversion efficiency of 9% and a power generation capacity of 128W, according to the company. Shipments have already begun in Europe and are slated to start in Japan within this year.
Sharp expects the panel to be used at apparel shops and convenience stores in suburban areas.
Sanyo showed off a tandem-type thin film solar panel developed by Sanyo Eneos Solar Co Ltd, which was jointly established by Sanyo and Nippon Oil Corp (Eneos) in January 2009, for the first time (See related article). It measures 1.4 x 1.1m. Sanyo did not reveal the conversion efficiency but reaffirmed the goal of achieving an efficiency of 10% by fiscal 2010.