Fuel-cell Assisted Bike Comes With

Li-ion Battery

Mar 9, 2010 10:03 Tsunenori Tomioka, Nikkei Monozukuri

Iwatani Corp exhibited a fuel-cell assisted bicycle that charges a lithium-ion (Li-ion) battery by using a polymer electrolyte fuel cell (PEFC) system with an output of about 60W.

The bicycle was showcased at FC Expo 2010, which took place from March 3 to 5, 2010, in Tokyo. And it is now being tested at the Kansai International Airport. The Li-ion battery (26V, 4Ah) supplies electricity to a motor. The PEFC system is mounted on the luggage carrier above the rear tire of the bicycle.

Hydrogen, which is used as a fuel, is stored in a hydrogen cartridge. When the cartridge is full and the battery is fully-charged, the bicycle can travel about 45km (it may change depending on driving conditions). The PEFC system can generate electricity for about three hours.

The PEFC system consists of the hydrogen cartridge, a coupler for connecting the cartridge, an adjusting valve for reducing the pressure of hydrogen coming from the cartridge, PEFC, a blower for sending air to the PEFC and a DC-DC converter.

The hydrogen cartridge stores hydrogen by using a hydrogen absorbing alloy. With an internal capacity of 0.25L, it can store 7g of hydrogen (equivalent to 80L under a pressure of 1 atm). It uses 750g of the hydrogen absorbing alloy that contains titanium zirconium.

With the coupler, the hydrogen cartridge can be attached just by inserting the inlet/outlet of the cartridge. When it is inserted, the adjusting valve opens. Though the pressure of the hydrogen coming from the cartridge does not exceed 1MPa, it is still high. Therefore, the valve is used to lower the pressure before the hydrogen is supplied to the PEFC system.

The output voltage of the PEFC is 30 to 35V. And it is lowered by the DC-DC converter to 26V to charge the Li-ion battery. The mass of the PEFC system is 1.1kg.

To fill the cartridge with hydrogen, a device called “bomb stocker” is used. It is installed in the Kansai International Airport.

According to Iwatani, the PEFC’s output power of 60W is not enough.

“Depending on driving conditions, it sometimes cannot supply the bicycle with enough electricity,” it said.

Currently, the company is not considering commercializing the bicycle, but it is aiming to enhance the output power of the PEFC system.

Sourced and published by Henry Sapiecha 16th March 2010

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