Toyota has developed two new high-pressure hydrogen storage tanks featuring greater capacity and longer operational life for its fuel cell vehicles. The tanks offer 35 megapascal (350 bar or 5,000 psi) storage and 70 megapascal (700 bar or 10,000 psi) storage.
Toyota designed the new high-pressure tanks are with an all-composite structure wrapped by a carbon fiber exterior and with an anti-leak liner made of high-strength nylon resin with superior hydrogen permeation-prevention performance.
The use of a nylon resin tank liner allows the liner to be thinner, meaning that the new 350-bar tank can hold 10% more hydrogen than the same-exterior-size 350-bar tank Toyota used before.
The extra capacity extends the cruising range of Toyota’s hydrogen fuel cell hybrid passenger vehicle from 300 km (186 miles) to 330 km (205 miles) in the Japanese test cycle.
The new 700-bar tank stores approximately 1.7 times more hydrogen than the previous 350-bar tank, resulting in a cruising range of more than 500km (311 miles) in the Japanese test cycle.
Both tanks have been certified by the High Pressure Gas Safety Institute of Japan—the 35MPa tank in April of last year and the 70MPa tank this past January. Additionally, this April, the 35MPa tank met the Institute’s new technical standard established in March for compressed hydrogen automobile fuel tanks, allowing it to be used for 15 years, compared to three years for previous tanks.
Both tanks also feature a high-pressure valve developed within the Toyota Group. This valve follows a new design that positions a solenoid shut-off valve inside the tank for increased reliability.
Although Toyota is clearly better known for its hybrid vehicle development, the company has pursued hydrogen technology as a longer-term solution in parallel. Toyota has developed all major fuel cell system components for its fuel cell vehicles itself, including the fuel cell stack.
Since 2002, 11 Toyota FCHVs have been leased in Japan and five in the U.S. Toyota is also active in applying its fuel cell technology to buses. In addition to conducting real-world verification tests with a fuel cell bus prototype operating within Tokyo’s metropolitan public bus system, Toyota currently has eight units of its FCHV-BUS transporting visitors between various venues at the EXPO 2005, Aichi, Japan. (Earlier post.)
Toyota will present technical details of the newly developed hydrogen tanks at the 2005 JSAE Annual Congress (Spring) to be held at the Pacifico Yokohama complex from May 18.