Um, right.
500kg - 1200lbs - projected weight.
I guess the "team" hasn't worked around cars very much.
The 24kWh of Nissan Leaf cells I have sitting in the shop weigh about 384 lbs. 1/2 that - 12kWh - close to their 10kWh is 192lbs.
The 50kW Toyota MGR motor/gearbox I have in the shop weighs 92lbs dry.
Believe me, I'm trying very hard to re-design the motor to reduce weight. And those batteries - that is the cell weight alone, without any box to protect them. Chargers and motor controllers also weigh something. OH, then we need a car - steering, suspension, wheels, windshield, seats etc etc.......
Good luck! You're shooting for less than weight of a completely optimised, stripped out F1 racecar.
https://en.wikipedia.org/wiki/Formula_One_car