Teijin Showcases Ultra-light Electric Concept Car

Apr 1, 2010
Motohiko Hamada, Nikkei Automotive Technology & Tsunenori Tomioka, Nikkei Monozukuri & Tatsuhiko Hayashi, Nikkei Automotive Technology
The PU_PA EV concept car
The PU_PA EV concept car
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Teijin Ltd made a concept car whose mass is less than 500kg by using its group businesses' materials and technologies, imaging a vehicle to come five to 10 years from now.

The concept car, which the company calls the "PU_PA EV," was made with technologies for trimming weight, hybrid electric vehicles (HEVs) and electric vehicles (EVs). It is exhibited at Teijin Mirai Studio, the company's exhibition hall, from March 30, 2010.

The PU_PA EV has a body made with Teijin's materials. The parts for the electric system including a motor and batteries as well as the parts for the driving and steering systems were purchased from other companies. The vehicle can actually be driven.

However, the EV has some safety problems to be solved and cannot be driven on a public road with a number plate. For example, the heat-absorbing polycarbonate resin that is used for its windows has half a density as glass and cannot be used for the front window. Also, the lights of the vehicle do not have enough light intensity, and it is not equipped with air-bags.

Teijin plans to find out about people's needs and collaborate with its clients including auto makers and parts makers by showing its auto-related technologies.

The mass of the PU_PA EV is 437kg, which is about half that of a normal EV. It is a two-seated vehicle with a normal speed of 60km/h and can run 100km per charge.

Reducing number of parts

The components of the vehicle were modularized by using, for example, an integral molding technology so that the number of parts can be reduced to about 100 (20 modules). If such an EV is made with a normal method, the number of parts will be 20,000 to 30,000.

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Reducing weight of body

The weight of the body was reduced by employing the core structure design of carbon composite material. The core structure is made by sandwiching a pre-formed urethane foam material between prepreg sheets and pressing them with heat to integrate them.

With the method, it is possible to enhance the rigidity of even a thin carbon fiber sheet. The shape forming was conducted at GH Craft Ltd, an affiliate company of Teijin.

Other materials, parts used for PU_PA EV

The interior materials for the sheets and mats are made with a biodegradable polyethylene terephthalate (PET), which contains fibers made from plant-derived ethylene glycol (30% by mass).

Also, Teijin used the "Teflex," a metallic film that eliminates the need for plating, so that a laser radar device, etc can be placed behind a metallic ornament. Though the film is coated with silver color and looks like aluminum, it actually is made of resin. It was employed for a suitcase of the Zero Halliburton brand.

As a code for the peripheries of tires (radial direction), Teijin used the "Teonex" PEN (polyethylene naphthalate) fiber to reduce road noise. The Teonex has already been employed for Bridgestone Corp's Regno GR9000 and Sumitomo Rubber Industries Ltd's Veuro VE302, which are tires developed in the aim of reducing noise.

Furthermore, the company used the "Cell Form" two-dimensional communication sheet, which enables multiple devices to wirelessly communicate with one another. It is made by arraying conductive fibers in a reticular pattern between two PEN sheets. With the sheet, electric devices such as a car navigation system can be placed anywhere on the dashboard.

Correction Notice: We replaced the sentence, "the heat-absorbing polycarbonate resin that is used for its windows ... can fly apart if it is broken," in the fourth paragraph with the sentence, "the heat-absorbing polycarbonate resin that is used for its windows ... cannot be used for the front window."