Stella Li, BYD’s senior vice president and head of its US operations, said the holdup was caused by BYD’s efforts to make the car roomier, especially its rear-seat area that was cramped thanks to a beefy battery pack that needs to be stored under the seat. In a recent telephone interview, she denied that the delay had anything to do with a possible intellectual-property infringement on certain battery technology by BYD.

...She said BYD plans to ship as many as 50 e6 electric cars by the end of next year to fleet customers in Southern California, including the municipal government of Los Angeles. BYD earlier this year began selling e6 cars to taxi operators in the southern Chinese city of Shenzhen and is collecting field data to improve the car. Ms. Li said BYD will make the e6 available for purchases by private buyers in the US in 2012. She declined to forecast demand, saying it “will depend on gasoline prices and other peripheral factors.”