Oil cooling. Besides this is a peak power value, so thermal constraints don't matter. Continous power is given around 350-400 kW. (Sources: https://yasa.com/ne

Oil cooling. Besides this is a peak power value, so thermal constraints don't matter. Continous power is given around 350-400 kW. (Sources: https://yasa.com/news/yasa-smashes-own-unofficial-power-density-world-record-pushing-state-of-the-art-electric-motor-to-staggering-new-59kw-kg-benchmark/ https://yasa.com/news/yasa-smashes-own-unofficial-power-dens... and https://yasa.com/technology/ https://yasa.com/technology/)