Toyota Motor Corporation (TMC) has been developing fuel cell vehicles (FCV) since 1992. In 2008 Toyota launched the "FCHV-adv" as part of a demonstration program. It established major technical improvements in key performance areas such as efficiency, driving range, durability and operation at subzero climate conditions. However, to attain commercialization and widespread adoption of FCV’s, further improvements in performance were required. During the FC system shutdown process of the FCHV-adv the purge process took a long time and output power was lower than normal operating conditions. The FC stack in the FCHV-adv required drying the electrolyte membrane to remove unneeded water from the stack. As a result, the resistance of the stack increased and caused low output power. In December 2014, TMC launched the world’s first commercially available FCV named the "Mirai" which greatly improved the power even after freezing start-up. To enable freezing start-up under high water content conditions oxygen diffusivity through the cell and a 3D fine mesh cathode flow channel were developed to improve the drainage control. In addition, control countermeasures were incorporated including water content measurement techniques and water purge control during parking (parking purge). The water content measurement uses low frequency impedance, which measures high water content accurately. Also, parking purge was developed to purge liquid water which migrates from the cathode to the anode during soak. Without the purge the water may clog the anode channel. As a result, the Toyota Mirai FC stack has improved output power after freezing start-up and shorter FC system shutdown operation.