500W with quality panels gives you a daily average of 2kWh over the year in a sunny country, however on sunny summer days 3kWh could be possible.
Considering that the PHEV uses only 9.6kWh of the battery and the older battery of a 2015 model would be less, having the car standing in the full sun with those panels for 2-3 days could make sense or even just extending the EV range for a few km a day if it is parked at work in the sun.
Bendable panels like those stuck on some yachts are 2-3mm thick and will increase drag only very little.
You will still need some kind buffer battery for the inverter and the problem is if the car will only accept at least 6A with 230V (I am working on that), you will need a fairly sizeable battery and inverter to deliver the required energy for the charge in bursts. LiFePO4 would be the best as sealed lead acid have
a poor cycle life which is useless in this application as they could be fully cycled 2- 3 times a day and then would last only 3-4 months.
I am seeing the LiFe's for $500-600 per kWh lately but still a lot of cost to recuperate.
I think the cost exceeds the benefit, those bendable panels are also not that cheap.
However if this is for bush camping and also running a compressor fridge, the cost might be very well justified, after all this is a SUV with off-road capabilities, so why not use them.
There is no way I am going bush without icy cold beer