No problem if you are using a laptop/notebook inside the car when battery status of the notebook/laptop is going to low (lowbat), because you can get the electric power source from the car battery, through the car cigarette lighter socket/terminal.
To get 220VAC electric power source from 12V DC(car battery) You must have 12V to 220V inverter. In the figure I use 200 watt inverter to drive my laptop adaptor.
Nowaday the price of inverter like in the figure is not expensive, below $30 US, and depends on capacity and brand name, more capacity of course will be more expensive. you can buy from computer accessories store or from online store. you can search this inverter using keyword 12 to 220 inverter.