New Technologies and Energy Harvesting
Rohm – New hydrogen fuel cells deliver higher efficiency and increase safetySep 19 2012 - New Technologies and Energy Harvesting [More New Technologies and Energy Harvesting Articles]
Rohm, together with Kyoto-based Aquafairy Corp. and Kyoto University, have co-developed compact, lightweight, high-power hydrogen fuel cells designed to power smartphones and other portable devices. The fuel cells overcome the drawbacks of dry cells, lithium-ion cells, and direct methanol fuel cells, significantly reducing weight and increasing output power while providing a higher level of safety, making it possible to provide power in places where AC power is not available or cannot be used, says the trio.
Fuel cells can be made smaller, lighter, and more efficient than conventional storage and rechargeable cells, and thus are expected to drive expansion into new markets and applications. In fact, there is already extensive use of fuel cells using methanol and hydrogen. However, methanol fuel cells have several disadvantages that prevent widespread acceptance. Unlike hydrogen fuel cells, it is difficult to increase power output. And hydrogen fuel cells require the use of cylinders, making them harder to handle and hinder efforts towards greater miniaturization.
Rohm and Aquafairy have recently succeeded in solidifying calcium hydride in a sheet configuration using proprietary technologies, generating approximately 4.5 litres of hydrogen from a sheet less than 3cc in volume (measuring 38 x 38 x 2mm), providing a power output of 5Whr. The hydrogen fuel cells are compact and can operate at ambient temperatures, making them suitable for use in smartphone chargers, tablet PCs, as power sources outdoors and in remote areas, and in emergency backup power supplies. In addition, they emit no carbon dioxide or hazardous gases and can be disposed of as general waste.
the trio will continue to work on assessing reliability and making further improvements, with production scheduled for April 2013. The fuel cells will be displayed at CEATEC (October 2012 in Tokyo) and Electronica (Munich, November 13-16, 2012).
In addition to expanding its lineup of hydrogen fuel cells for smartphone chargers, Rohm and Aquafairy, in collaboration with Kinkei System Corp., are also developing fuel cells for powering seismometers in remote areas that prevent the use of traditional power supplies. Compared with conventional lead batteries, the cells reduce weight by 1/4 with same capacity, making it possible to provide 400Whr from a device that weighs only 3kg. Example devices will be showcased at electronica in Munich (Nov. 13-16), Hall A5-542.
Summary by Professor Hirao, Kyoto University (presented at a news conference) : In recent years it has been often suggested we use hydrogen as an energy source since it is a type of clean energy. This brought about the development of hydrogen fuel cell powered vehicles. Since gases emitted from these vehicles contain no nitrogen oxides, particulate matters, carbon dioxide, or other harmful substances, they are expected to significantly reduce environmental pollution and global warming. However, hydrogen requires a large storage volume, making it impractical for automotive applications. Up to now, hydrogen-generating devices are equipped with a resolver that resolves a hydrogen source composed of ammonia and hydrazine through a catalytic reaction in order to supply hydrogen to the fuel cells. But the use of ammonia brings up another problem since it is designated as a deleterious substance.
There is also an increasing demand for fuel cells to become more compact for use as a replacement for AC-DC converters with rechargeable secondary cells used in mobile phones, portable information terminals, digital cameras, and notebook computers.
The hydrogen fuel cells co-developed by ROHM and Aquafairy offer distinct advantages over conventional types of fuel cells in terms of compactness and output power levels. One is a proprietary technology that solidifies calcium hydride (a calcium compound) into a compact sheet configuration in order to stably produce hydrogen through the water drop method, and another is a low-profile, integrated cell-forming technology.
Rohm and Aquafairy have also launched a joint project for a compact, lightweight 400W fuel cell system with Kinkei System Corporation, which is expected to become mainstream once the power generation capacity is increased.
We at the laboratory of Professor Kazuyuki Hirao in Kyoto University’s Graduate School of Engineering have also joined in the collaboration, and have already discovered a new, high-efficiency, low-priced calcium compound that can be incorporated in fuel cell systems and easily broken down into raw materials and recycled using a special laser. This next-generation regenerative recycling hydrogen-generating agent is currently being developed at the Kyodai Katsura Venture Plaza adjacent to Kyoto University’s Katsura Campus.