SHANGHAI, April 18 (Reuters) – BHP Billiton aims to start producing nickel sulphate at its Nickel West project in Australia next year to tap demand from the battery sector, a company executive said on Wednesday, adding that the project was now targeting production of 90,000 tonnes of nickel metal. “This is an increase from our previously advised target of 84,000 tonnes by identifying additional de-bottlenecking opportunities,” said, Eduard Haegel, Nickel West asset president at BHP Billiton, speaking at a battery materials conference in Shanghai.