If it's any of the main concerns of the Switch, it would be a possibility of having a short battery life (Less than 5 hours) but Nvidia has technology called BatteryBoost
It says in the description:
"BatteryBoost is a new ultra efficient mode that extends your gaming time by up to 2x on battery, while delivering the great 30+ FPS gaming experience you demand. BatteryBoost technology is completely automatic, turning on the second you fire up a game when you’re unplugged. Plus, it works hand in hand with NVIDIA Optimus technology, giving you extra-long battery life when running casual apps, and the best performance when you’re gaming."
So BatteryBoost (as the name states) boosts battery life, it's normally used for laptops but maybe the Switch can use BatteryBoost too to possibly solve the solution of having a short battery life.
Discussion started at here by super_ahmed109011