Producers of electric-car batteries such as LG Chem Ltd. (051910) and Johnson Controls Inc. (JCI) are building new plants at such a pace that capacity will grow to almost double automakers’ demand, a Bloomberg New Energy Finance report shows.While manufacturers will have capacity to make 35 gigawatt hours of batteries by 2013, carmakers have committed to produce as many as 839,000 plug-in electric vehicles needing a total of 18 gigawatt-hours of storage, the London-based researcher said.“The larger, mainly Asian, conglomerates can cope with limited demand and compete by lowering prices but smaller pure- play battery makers will be left vying for an increasingly limited number of supply contracts,” said Ali Izadi-Najafabadi, an energy technologies analyst at New Energy Finance.The glut of factories may push smaller manufacturers out of the running for orders and into areas such as energy storage for surplus power from electricity grids, according to today’s report. Battery prices may also decline to $350 per kilowatt- hour in 2020 from $800 to $1,000 now, New Energy Finance said.Among Asian companies best able to cope with the surplus are LG Chem, South Korea’s biggest chemicals maker, Seoul-based SK Innovation Co., Toshiba Corp. (6502) in Tokyo and SB LiMotive, a joint venture between Samsung Electronics Co. and Robert Bosch GmbH, said Shu Sun, another analyst at the research group.LG Chem in April said it aims to spend 2 trillion won ($1.8 billion) by 2013 to expand its battery capacity for electric cars. Nissan Motor Co. plans to make 500,000 batteries a year by 2015 through its Automotive Energy Supply Corp. venture.Nissan, based in Yokohama, Japan, and Detroit-based General Motors Co. (GM) both began selling new electric cars in December. Battery making has surged in the U.S., where spending under the government’s Recovery Act has channeled about $2.4 billion into the products, their components and charging infrastructure for vehicles, according to U.S. Department of Energy figures.The U.S. is set to hold as much as 40 percent of capacity by 2015, up from 2 percent before the stimulus, according to the energy department. Of companies receiving funding, Ener1 Inc. (HEV)’s EnerDel unit is expected to struggle the most, Sun said. It received a grant of $118.5 million for a plant in Indianapolis.Brian Sinderson, a spokesman for Ener1, didn’t immediately reply to an e-mail and voicemail seeking comment.The department also provided $299.2 million for a Johnson Controls factory in Holland, Michigan, the largest grant under the program. Waltham, Massachusetts-based A123 Systems Inc. (AONE) got $249.1 million for plant at Romulus and Brownstown in the state.