After Gutenberg

Mitsubishi Electric entered the photo voltaic market in the United States in mid-2005. At present, Japan is the second largest in terms of manufacture of solar cells, trailing Germany and leading China.

This is good news, at least in the opinion of GCC commentator sjc. Multi-crystalline cells are easier and cheaper to manufacture than mono-crystalline, but have been unable to reduce significantly the cost of solar power because they are less efficient.

Green Car Congress relays an announcement from Mitsubishi Electric that may mean multi-crystalline silicon solar cells regain some of the market share they have begun to lose to thin-film photo voltaic laminates. This blog recently relayed an opinion expressed by Jim Fraser that China’s largest manufacturers of photo voltaic solar cells would be providing some stiff competition to other manufacturers.

Suntech makes PVL with deposits of amorphous and micro-crystalline silicon on glass substrate. Material costs are kept low by using less than 2% of the silicon required to manufacture equivalent crystalline silicon PV products. Suntech currently projects an initial production cost of approximately $1.20 per watt (based on 6% solar conversion efficiency).

On the other hand, their thin film modules will have a solar conversion efficiency of 6% to 9%. Six percent conversion efficiency has become a minimal expect value in the business. Still Suntech forecasts a further decline in production cost, as both production scale and conversion efficiencies increase, which is a truism for the industry as a whole. Thus, the Mitsubishi Electric announcement is timely; they have achieved a photoelectric conversion efficiency rate of 18.0%, which should make them more competitive.

Mitsubishi added a low reflectivity surface texture on the multi-crystalline silicon, developed a process to print electrodes on the surface of the silicon (metallization) and reduced shade loss of the front grid electrodes. In the same surface area as previous products, the company achieved a 7% greater electric output.

“All Your Photons Are Belong to Us”

Main features:

1. Increased light absorption using a unique Reactive Ion Etching (RIE) method. Using a nano-sized mask material, the RIE method uses highly reactive ions generated by RF plasma, letting ions precisely etch the target materials. This decreases reflectivity from the texturized surface of the multi-crystalline silicon, increasing the amount of absorbed light. This process is based in part on the result of the NEDO (New Energy and Industrial Technology Development Organization) project for R&D of innovative next-generation photovoltaic system technology.

2. Suppresses reduced electrical performance in crystalline. New metal electrode material reduces metallization time by approximately half that of previous models, and sustains electrical performance of crystalline.

3. Expanded effective electrical output surface area. Using modified screens and front metal electrodes, Mitsubishi reduced shading loss of front grid electrodes by 40% compared with its conventional cells.

Mitsubishi plans to introduce this technology after the end of 2007. While the solar market is undergoing remarkable growth, it remains a very competitive business where the interplay between technological development and mass-production techniques can spell the difference in whether a company can succeed in making and selling photo voltaic modules.

This blog has noted with interest diversification by a company in India. With extensive experience in high volume manufacturing of optical media, Moser Baer has chosen to enter the photo voltaic market, first purchasing some production equipment from a U.S. company, then securing a solar wafer supply from a German company. Part of the interest is in what markets they hope to target.