The fuel cell stack with a high output density
The fuel cell stack with a high output density
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Toyota Motor Corp had a press conference to explain its technologies Sept 24, 2012, in Japan and unveiled its fuel cell stack that the company has been developing for its fuel-cell vehicle (sedan) to be launched in 2015.

"At this point, it has the world's highest output density of 3kW/L," Toyota said.

The output density of the new fuel cell stack is more than twice as high as that of the "FCHV-adv," the company's existing fuel cell stack, while the company reduced volume by about half.

What contributed most to the improvement of output density is a technology to form electrodes. Specifically, a production technology for applying a platinum-based catalyst whose particles have a diameter of several micrometers without condensing it greatly contributed to the improvement.

"We made low-profile improvements to a method for kneading it, a method for applying it and so forth," Toyota said.

This time, Toyota applied the catalyst to a support medium by using a spray. The company has been developing fluorine-based and carbon hydride-based polyelectrolyte films at the same time. And it has not yet decided which will be employed. The company decided to employ a metal separator, considering to use titanium alloy.

The stack is integrated with several hundred cells, a booster converter and auxiliaries such as a pump to circulate water. Because of its small size, the fuel cell stack can be installed under a front seat of a vehicle. And the booster converter can be placed between the driver's seat and the front passenger seat.

"The price of the fuel-cell vehicle will be set so that it becomes acceptable to customers," Toyota said.