NEW YORK - Tesla Motors has unveiled plans for a "gigafactory" to assemble advanced batteries for electric cars.It's part of a plan to move from niche manufacturer to the big-time for battery cars.The company said on its blog that the factory required an investment of around R49-billion and would include partners; some reports mention Japanese group Panasonic.MEGA PRICE CUTS Tesla said: "The gigafactory is intended to reduce cell costs much faster than the status quo and by 2020 to produce more lithium-ion batteries a year than were produced worldwide in 2013."The idea is to cut the price per kiloWatt hour of battery packs by more than a third. Tesla said it would invest $2-billion an equivalent of R22-billion of its own money in the factory.The company said in a document filed with US regulators: "At full implementation the Tesla gigafactory is expected to have 6500 dedicated Tesla and production partner employees. It is expected to attain full production capacity in 2020, sufficient for about 500,000 vehicles a year, and stationary storage applications."The company expected the factory to be built in Arizona, Nevada, New Mexico or Texas and Japanese daily newspaper Nikkei said it would handle everything from processing raw material to assembly.Panasonic said: "It was studying every possible way to strengthen ties with Tesla". But would not confirm the report.