Development of High-Pressure Hydrogen Storage System for New FCV

This paper describes the high-pressure hydrogen storage system developed for new FCV. With the aim of further popularizing FCVs, this development succeeded in improving the performance of the system and reducing costs. This new storage system consists of multiple tanks of different sizes, which were optimized to store the necessary amount of hydrogen without sacrificing the interior space of the vehicle. The new tanks achieved one of the highest volume efficiencies in the world by adopting high-strength carbon fiber, developed in conjunction with the carbon fiber manufacturer, and by optimizing the layered construction design which allowed the amount of carbon fiber to be reduced. To increase the amount of available hydrogen, the longer high pressure tanks were mounted under the vehicle floor unlike the previous model. This was accomplished by the following two measures: First, individual design and manufacturing measures for the tanks were adopted. The liner shape was optimized to adjust to rapid refueling at extremely low temperatures. The molding conditions were optimized to streamline the manufacturing process and prevent molding defects. Second, the high-pressure storage system was optimized as an integrated system. Despite adopting multiple tanks with different sizes, the same high filling efficiency of the previous system was ensured by optimizing the arrangement of the temperature sensor and the hydrogen ejection angle. Additionally, various cost reduction measures were adopted. The manufacturing time was reduced by accelerating the resin curing using a new material for CFRP (Carbon Fiber Reinforced Plastic) high pressure tanks, and by adopting a new machining method for the tank valves and regulator. These measures helped to significantly reduce the manufacturing costs of the new high-pressure hydrogen storage system.