Toyota Motor Corp will build batteries for its hybrids in North America eventually, as part of a plan to drive down the production costs of fuel-efficient models like its top-selling Prius.As part of that strategy, Toyota expects that its next-generation Prius will have a profit margin close to that of a traditional sedan like the Corolla, a senior executive said on Friday.Toyota, like other major automakers, does not typically detail vehicle-by-vehicle profitability. But the high cost of developing new hybrid systems and batteries has widely been seen as a constraint on the initial profitability of such models.U.S. automaker General Motors Corp (GM.N: Quote, Profile, Research, Stock Buzz) has said it expects to lose money initially by selling its all-electric Chevy Volt, due to the high cost of battery packs.