A push to offer long warranties for batteries used in electric cars is one factor forcing lithium miners to change the way they sell their product, according to one of Australia's biggest producers.

US company Albemarle, which owns 49 per cent of the lithium-rich Greenbushes spodumene mine in Western Australia, said battery manufacturers are increasingly demanding 10-year contracts in a bid to secure supply. The comments came as the New York listed company indicated first production on its $400 million lithium hydroxide plant in WA may come a year later than previously expected.