unless the laptop is a power ohg
It should be possible. In fact there are two ways you could consider.
Firstly, there are inverters that plug into the cig lighter and provide a 220/240 power source.
However as most laptops only really need around 12-20v, with a load of between 1-2 amps, a regular DC charger should be available for your model. Do an Internet search for something like :
laptop car charger dell latitude
I had like 90 hits with that search pattern. Be aware of phrases such as this one though :
In car charger for Dell Latitude D400/D600/D800/M60, and Inspiron 8500/300m/400m/500m/600m notebooks. Please note that Dell has built technology into some of its newer models that will not allow charging by anything other than a Dell adapter, so on those models this item will work as a power adapter but will not charge the battery.