Toshiba Corporation today announced the world’s first prototype of a small form factor direct methanol fuel cell (DMFC) for portable PCs, a clean energy breakthrough with the potential to end reliance on rechargeable batteries. The new fuel cell currently realizes average output of 12W and maximum output of 20W, and can achieve approximately five hours of operation with a single cartridge of fuel. It provides instant power supply, and achieves significant advances in operating times with replaceable methanol cartridges.
Toshiba will present the DMFC at CeBIT in Hannover, Germany from March 12 to 19.
The hardware capabilities of notebook PCs, cellular phones, PDAs and other portable devices continue to make rapid progress, However, faster CPUs, higher resolution displays, wireless connectivity and other advances all increase the demands on power supply and underline the limitations of current lithium-ion batteries.
Fuel cells are widely seen as a replacement for lithium-ion batteries, but companies working on their development have to overcome the problems of miniaturization and fuel delivery. Toshiba has achieved this with its DMFC.
Methanol in a fuel cell delivers power most efficiently when it is mixed with water in a 3 to 6% methanol concentration–a concentration requiring a fuel tank that is much too large for use with portable equipment. Toshiba overcame this by developing a system that allows a higher concentration of methanol to be diluted by the water produced as a by-product of the power generation process. This technology allows methanol to be stored at a much higher concentration, and achieves a fuel tank less than 1/10 the size of that required for storing the same volume of methanol in a 3 to 6% concentration. The current prototype can operate for approximately five hours on 50cc of high concentration methanol.
Alongside this, Toshiba realized essential technologies for miniaturization of a high performance fuel cell. These include interface and electric circuits to assure efficient control of power supply; sensors to monitor methanol concentration and liquid level; and a remaining quantity sensor to tell users when they need to change the methanol fuel cartridge. All these components, and low power liquid and air transmission pumps, are controlled by a super small DC-DC converter.
For the cell itself, Toshiba developed a new material that allows smaller cells, allowing for miniaturization of the cell stacks.
One of Toshiba’s main concerns in developing the DFMC was optimized operating efficiency, to assure that the fuel cell generates power at the required level, with minimal waste of energy. Towards this, the company investigated such factors as fuel density and circulation, and air supply levels, all in order to map the best operating conditions for a miniaturized fuel cell. In addition, the PC sends information on its operating status to the fuel cell in order to balance power demand and supply. Any unused energy is stored in the DMFC and can be drawn on when the PC requires extra power.
Toshiba has given the DMFC the same electrodes as found in lithium-ion batteries, allowing it to connect directly to a PC or other portable device in the same way as an lithium-ion battery. It can also be used as an alternative to lithium-ion batteries. The DMFC removes the need for proximity to a mains power supply to assure long operating times.
Toshiba will continue development of DFMC technology, with the aim of product commercialization within 2004. The current DMFC will be on display at Toshiba’s booth at CeBIT, in Hall 1 6h2.
Product Methanol fuel cell directly connected to the PC
Output Average 12W
Size 275 x 75 x 40mm (825cc)
Operating hours Approximately five hours with 50cc, and 10 hours with 100cc, of high concentration methanol fuel
Cartridge weight 120g (100cc), 72g (50cc) (Approximate)
Cartridge size 100cc: 50 x 65 x 35mm 50cc: 33x 65 x35mm