You can use 8x AAs if there isn’t a place to plug in.
The pump parts can be tough to disassemble. Be ready to buy replacement parts.
Not that we have much say when it comes to breast pumps, but if you do come face to face with one of these, it helps to have some tips. It is pretty straightforward to use and my wife went back to using this for #2 instead of using the brand new hospital-grade Spectra that we got.
Keep batteries ready in the battery pack and keep them fresh, but this should be a last-resort power source.
Have an inverter in the car to plug into if she wants to pump while driving or parked.
Keep tongue and groove pliers in case there is a pump part that needs loosening (the part that milk drips from into the bottle). Have small brushes to clean the pump parts.
Buy replacement pump parts early. Trust me.