McLaren says it's testing pure-electric technology, but hasn't cracked the code for delivering the range and performance expected of a supercar.

Dan Parry-Williams, engineering and design director, says the company has an EV mule running around, but battery technology isn't yet conducive to flat-out driving.

“We’ve got a pure EV  mule and part of the reason for that is to ask how we can deliver driver engagement in a fully electric world,” Parry-Williams told Autocar. “But there’s still quite a journey from here to there in terms of our products.”

“Let’s say you want to drive on track for half an hour,” he continued. “If that was an EV, that car would have over 500 miles of [road] EV range, and it would be flat as a pancake at the end. The energy required to do really high performance on track is staggering. And then you have to recharge it.”

Above: Expect to see one of these in the next generation of McLarens 

Parry-Williams didn't just talk about range, he also mentioned power density as a factor holding electric supercars back.

While manufacturers are focusing heavily on energy density – crucial for extending range – the McLaren man said batteries capable of sustaining the power levels required for a supercar require a different development path altogether.

Before we see fully-electric McLaren supercars, expect to see hybrid augmentation spreading across the range. Half the range is expected to be electrified by 2022.