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TOKYO -- A fuel cell technology that promises a quick fix for dead or dying mobile phone batteries may make its world debut in Japan in 2007, according to representatives of Japan's two biggest mobile communications carriers today at the Wireless Japan 2005 Expo.

For years, DMFCs (direct methanol fuel cells), which typically work by mixing methanol with air and water to produce electrical power, have been promoted as an alternative to the lithium ion batteries used in notebook PCs and other portable electronics gear. DMFCs are useful because power can be obtained instantly by inserting a fuel cartridge recharger, developers say.

Some of Japan's biggest consumer electronics companies have been developing DMFCs, but prototypes shown to date have been too big and bulky or have been incapable of producing enough power to permit commercial production.

That seems to be changing though.

NTT DoCoMo and KDDI, Japan's number one and number two mobile communications carriers, plan to have fuel cell rechargers for mobile phones in shops the year after next, officials from both companies said.

Japan's mobile phone vendors spent years trying to get the battery life of third-generation mobile phones to match that of the country's second-generation digital phones. Next year a new problem will hit vendors when they put power-hungry digital TV receivers into phones and when the country's digital TV network goes nationwide. The antennas will knock usage time back down and that's where DMFCs will help, vendors and carriers say.

Prototype on Display

In DoCoMo's case, the company has a prototype charger on display at Wireless Japan. The device, which DoCoMo is developing in association with Fujitsu Laboratories, will appeal to members of the carrier's base of nearly 50 million subscribers who are looking for a quick power fix, said Kazuhiko Takeno, a manager at the company's Technical Support Group.

The recharger, which has a cradle design, is still a bit bulky at 5.9 inches by 2.2 inches by 1 inch, and it weighs 6.7 ounces. But it has enough juice to do the job. The carrier's customers should be able to buy a commercial version around mid-2007, Takeno said.

The version on display at the Expo improves considerably on an earlier model that the company showed last September, he said. That's because, despite being about the same size and volume as the older model (which is marginally thinner), the new prototype has enough power to recharge a mobile phone battery three times, which is much nearer to being worthwhile for customers, he said.

The latest version uses a 0.6-ounce shot of fuel, just as the older model did; the prior model, however, could recharge a battery only once, Takeno said.

Improved Technology

Fuel-cell technology is also looking viable for KDDI's customers, according to Youichi Iriuchijima, an assistant manager at the company's IT Development Division.

At last October's Ceatec Japan 2004 exhibition, Iriuchijima showed prototype rechargers from Hitachi and Toshiba, saying that improved versions would be on the market in 2006. That schedule has slipped to January 2007, mainly because that's when regulations will be changed to allow passengers to carry methanol on planes, he said.

Both Hitachi and Toshiba have improved their technology over the past nine months, he said.

Whereas the designs shown last October were only mock-ups and displayed under glass, this year's versions actually produce electricity. To prove the point, he took a vial of diluted methanol and plugged it into the side of the Hitachi recharger, and the mobile phone it was supposed to power immediately sprang into electronic life.

The two working prototypes take a different approach to Fujitsu's models, however, being boxes that use cords to feed power to the mobile phones.

The Hitachi version is 4.8 inches by 3 inches by 3 inches, weighs about 6 ounces and offers two recharging options. A 0.06-ounce vial of fuel, which snaps into the side of the device, can power a mobile phone for about an hour, while a 0.5-ounce vial yields about 5 hours of power, Iriuchijima said.

The Toshiba version is bigger, at 4.5 inches by 4.4 inches by 1 inch, and the prototype weighs 8.8 ounces, about twice the weight of a typical Japanese-model third-generation mobile phone. But size brings power in Toshiba's case: A 0.7-ounce vial of fuel can deliver 20 hours of power, he said.

These specifications weren't available last year and will change for the commercial models, Iriuchijima said. He did not reveal pricing or other details.