Fuel tank made of polyketone and method of manufacturing the same

A method of manufacturing a fuel tank using polyketone, comprising:

• injection-molding an upper cover and a lower cover using an injection-molding machine;
• placing the upper cover and the lower cover, injection-molded in the injection-molding, at a relatively high position and a relatively low position, respectively, and assembling the upper cover and the lower cover with each other;
• and
• bonding contact surfaces between the upper cover and the lower cover, assembled with each other in the assembling, to each other using a laser beam,
• wherein the upper cover and the lower cover, injection-molded by the injection-molding machine, are made of polyketone so as to improve rigidity thereof,
• the method further comprises pressurizing an outer side surface of at least one of the upper cover and the lower cover using at least one roller between the assembling and the bonding,
• the bonding is performed while the roller pressurizes the outer side surface of at least one of the upper cover and the lower cover in the pressurizing,
• the upper cover and the lower cover have edges having shapes corresponding to each other such that one of the upper cover and the lower cover has a protruding portion formed on the edge thereof and a remaining one has an insertion recess formed in the edge thereof, into which the protruding portion is fitted, and
• each of the protruding portion and the insertion recess has at least one support surface formed in one side surface thereof, the support surface being parallel to outer side surfaces of the upper cover and the lower cover so as to support a pressurization force of the roller pressurizing the outer side surface of at least one of the upper cover and the lower cover in the pressurizing,
• wherein the injection-molding includes injection-molding an intermediate cover, the intermediate cover having insertion recesses formed therein, into which a lowermost edge of the upper cover and an uppermost edge of the lower cover are fitted,
• the assembling includes assembling the intermediate cover between the upper cover and the lower cover, and
• the bonding includes bonding contact surfaces between the upper cover and the intermediate cover to each other and bonding contact surfaces between the lower cover and the intermediate cover to each other using the laser beam.