Power bank for tent camping

I don’t mean to be a diva, because it’s noise related (tho I am aware of festival temps lol) - but I need a box fan to sleep even in the dead of winter…suggestions for a power bank that I can plug a fan into for each night? The only ones I’ve found seem pretty heavy duty so I just want to make sure I’m looking at the right stuff - thank you!! 🙏🏻