Key to Tesla battery manufacturing is still in Germany

Tesla, the electric-car maker -- which still plans to make about 2,500 of the cars a week by the end of March -- designed a new automated system for module production at its battery factory near Reno, Nevada. The line is already working at Tesla’s German manufacturing unit Grohmann but needs to be shipped to the US next month to be put to use, Chief Executive Officer Elon Musk said.

"That’s got to be disassembled, brought over to the Gigafactory, and re-assembled and then brought into operation at the Gigafactory. It’s not a question of whether it works or not. It’s just a question of disassembly, transport and reassembly," he said on a conference call Wednesday. Once that milestone is completed, Tesla will next need to fix material-handling constraints at its Fremont, California, assembly plant before it can reach its goal to make 5,000 Model 3 sedans a week by the end of June.