Toyota Motor Corp's "Mirai" fuel-cell vehicle
Toyota Motor Corp's "Mirai" fuel-cell vehicle
[Click to enlarge image]

Toray Industries Inc announced Nov 19, 2014, that its thermoplastic carbon-fiber reinforced plastic (CFRP) has been employed for Toyota Motor Corp's "Mirai" fuel-cell vehicle to be launched Dec 15, 2014.

The CFRP is used as a stack frame that protects fuel cells. It is a large part that corresponds to the floor of the vehicle. The thermoplastic CFRP was co-developed by Toray and Toyota.

The part is made by evenly dispersing carbon fibers (cut into a certain length) in polyamide (PA) to form a sheet-like intermediate base material and pressing it into a shape. An about one-minute forming cycle was realized by taking advantage of the fact that thermoplastic resins do not need a hardening reaction. It is almost the same as the takt (cycle) time at auto assembly plants, making it easy to support auto production lines.

Compared with thermosetting CFRPs, which are more commonly used, thermoplastic CFRPs feature a high productivity and low cost. They are considered as the most promising CFRP for automobiles. However, the dimensional accuracy of thermoplastic CFRPs is inferior to that of thermosetting CFRPs, and that has been considered a problem.

General Motors (GM) Co and Teijin Ltd have been engaged in a joint project to apply thermoplastic CFRPs to vehicles to be mass-produced, and the project is in its final phase (See related article).

Toray also announced that its carbon fiber has been employed as the base material for the Mirai's fuel cell electrode and the structural material for the vehicle's high-pressure hydrogen tank.