Fortescue chief executive Elizabeth Gaines has defended the $US223 million ($311 million) price tag the iron ore miner has put on the company that supplies batteries to the Formula E electric vehicle racing championship, saying it is common for technology deals to be priced on revenue rather than profits.

Fortescue has agreed to buy a battery and engineering company with historic links to the famous Williams Formula One motorsport team, in a deal the miner says will help it build batteries for trucks and trains.