Thus far, the Roadster, Model S and Model X have used commodity 18650 format cells. Other manufacturers with their own factories have instead gone for large format cells. Tesla's decision was pragmatic in that economies of scale kept costs low, but that much wiring is complex and has other issues. Now that Tesla will have their own battery factory, I don't personally see any reason not to follow what everyone else has done--large format batteries. I predict that this will happen with the Model 3 release and completion of the Gigafactory. What do you think?