Depends on the relative efficiency, how the charging rate tapers, and whether the additional consumption leads to extra stops.How many folk travel over 500 miles at >=85 mph? Outside urban areas, when traffic is light, 85 is normally the slowest I go. Especially in areas with speed limits of 75mph or higher.
It makes no sense in going fast to cut travel time, when you must use the time savings to recharge more often.
In the Model S 85, due to the tapering of charging rate, it's better to drive faster up to about 100mph.
It's also worth noting that additional charging time is additional time out of the car.
Depends on the speed of the route and what you're doing for food. If you're driving a Model S90D at about 55mph, and stop at a Supercharger for lunch around the middle of the route ...A Volt should go 500 miles faster than any BEV. I don't even think it would be close.
Realistically, a BEV is never going to be as fast as an ICEV for long trips. Gas is typically pumped at 5 to 10 gallons per minute. Typical mid-size fuel tanks have 15 gallon fills. Get 30mpg and you get 450 miles for 3 minutes "charging".
But, what you lose on the long trips you gain on the daily grind. And, you don't have to listen to an engine.