Development of the Fuel Cell System in the Mirai FCV 2016-01-1185

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) system technology since 1992. In 2008 the Toyota "FCHV-adv" was released as part of a demonstration program. It established major improvements in key performance areas such as cold start/drive capability, efficiency, driving range, and durability. However, in order to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs), improvements in performance and further reductions in size and cost were required.In December 2014, Toyota launched the world’s first commercially available fuel cell vehicle (FCV) the "Mirai" powered by the Toyota Fuel Cell System (TFCS). Simplicity, reliability and efficiency have been significantly improved within the Toyota TFCS. As a result, the Mirai has become an attractive vehicle which could lead the way towards full-scale popularization of FCVs. In order for a fuel cell system to generate power stably, the humidity of the electrolyte membrane must be controlled appropriately. Conventional humidity control is acheived by implementing an external humidifier. However, an external humidifier will increase air system pressure loss which increases the load of the system and requires extra parts increasing system complexity. Therefore, TFCS took on the challenge of adopting the world’s first FC system without an external humidifier through improving water management within the fuel cell itself and technical innovation of the control logic. An equivalent cruising range to conventional gasoline vehicles is another distinguishing characteristic of FCVs. Despite having less hydrogen capacity than the Toyota FCHV-adv due to packaging and cost constraints, the Mirai achieved a similar cruising range to gasoline vehicles by incorporating measures in the TFCS that improved fuel economy by approximately 20% by reducing crossover and increasing the efficiency of the air compressor.