Tesla's has announced that it is to become a technical partner in a nickel mine, nickel being vital for lithium-ion batteries that power electric cars

Elon Musk's car firm will also buy nickel from the Goro mine on the New Caledonia, small Pacific island, in order to secure its long-term supply. The move comes amid growing concerns about future supplies of nickel.

New Caledonia is the world's fourth largest nickel producer having seen a 26% rally in prices in the past year.

"Nickel is our biggest concern for scaling lithium-ion cell production," Musk said on Twitter last month.

Tesla will be a 'technical and industrial partner' to aid product and sustainability standards, but will not have an equity stake. However, the partnership will give it greater control over its battery supply chain.