BMW has doubled battery production capacity at its plant in Spartanburg, South Carolina, in preparation for an onslaught of new plug-in hybrid models.

The plant is the biggest in BMW's global production network and currently responsible for the X3, X4, X5, X6 and X7 lines.

The automaker said Wednesday that it has invested more than $10 million to add an extra 86,000 square feet to the plant and install a new battery assembly line. This essentially doubles the capacity for battery production at the site, according to Michael Nikolaides, BMW's head of electrified drivetrains.

BMW vehicles in production at the Spartanburg, South Carolina plant

BMW vehicles in production at the Spartanburg, South Carolina plant

Approximately 120 staff will work on the battery assembly line, which also covers quality inspection along with end-of-line testing. An additional 225 staff will work on BMW's plug-in hybrids that will use the locally sourced batteries.

The batteries will initially go into plug-in hybrid versions of the X3 and X5 due on the market in 2020, namely the new X3 xDrive30e and X5 xDrive45e. Eventually, though, we should see the batteries used in plug-in hybrid versions of the X4, X6 and X7 as well.

BMW has a target to have 25 electrified vehicles in its lineup by the end of 2023. Of these, 12 will be battery-electric models and the remaining 13 will be plug-in hybrids.