In the prototypes exhibited, a DMFC powers a device with current output between 550 and 600mW. The Li-ion acts as a secondary battery to supplement power when the output demand grows to more than 600mW. When the power need is less than 550mW, the DMFC’s excess power is channeled back to charge the Li-ion battery.

Sony’s designs, showcased at the FC Expo 2009, included a cordless speaker system and two mobile device chargers (portable and standard version), using an integrated hybrid fuel cell and lithium-ion battery. All of the designs showcased contain varying amounts of fuel methanol in a see-through tank – the portable design holds 10cc, the standard 100cc, and the wireless speaker 270cc of fuel.

The mobile device chargers may be connected to mobile phones or MP3 players via a USB connection. The portable device charger, with the 10cc methanol tank, has the power capacity equivalent to 13Wh when combined with the 3.7Wh Li-ion battery. In functional terms, this degree of power can fully charge a 3.4 to 4Wh mobile phone several times before requiring a refill. 

The larger version comes with a 100cc methanol tank, Li-ion battery, and two USB ports for simultaneous connection of two different devices. With a larger tank, this device can handle 25 power charges during a one-month period. The portable design resembles a small retro radio and can be carried in your hand or pocket. The larger version is intended as an indoor power source which you can move from one area to another, but is not intended to be carried with you.The cordless speaker system contains four fuel cells and a Li-ion battery, all embedded within the speaker.

A 270cc methanol tank, prominently located under the DMFCs, is illuminated by colored LEDs underneath the transparent tank. The speaker can be used 2-3 hours a week for a year before there is a need to refill the methanol tank. Up to 2W is supplied by the four 550-to-600mW DMFCs and the maximum output of the speaker is about 10W. If the power output of the speaker exceeds 2W, the Li-ion secondary battery will automatically assist in meeting the power needs.

Current DMFCs may be limited in the power they can produce, but they have a very high energy density which can be stored in a fairly small space, producing a small amount of power over a long period of time.  DMFCs are presently a poor choice for directly powering vehicles for example, but ideal for devices such as mobile phones, digital cameras, MP3 players, or laptops. While Sony has no plans for a commercial launch of the DMFCs in the immediate future, they continue with their research and development of alternative energy sources.

TFOT has recently covered Toshiba’s prototype DFMC internet viewer on display at the recent CES show in Las Vegas. In 2007 TFOT covered a battery that generates electricity from carbohydrates (sugar) developed by Sony. TFOT also covered numerous stories related to fuel cells and alternative energy sources, including the world's smallest fuel cell, platinum free fuel cell, super fuel cells, and bio-based solar cells.

More information on Sony’s hybrid fuel cell can be found here.