A year and a half ago, Apple Inc (AAPL.O) had applied for just eight patents related to auto batteries. Recently, it has hired a bevy of engineers, just one of whom had already filed for 17 in his former career, according to a Thomson Reuters analysis. The recent spate of hires and patent filings reviewed by Reuters shows that Apple is fast building its industrial lithium-ion battery capabilities, adding to evidence the iPhone maker may be developing a car.