Apple has announced a free battery recall and replacement program for MacBook Pros with Retina display sold between September 2015 and February 2017. The company says that the batteries in these units are likely to overheat and pose a safety risk. Customers can check the serial number of their MacBook Pro on Apple's website for eligibility.
https://www.notebookcheck.net/Apple-announces-a-voluntary-battery-recall-program-for-certain-15-inch-MacBook-Pro-laptops.424901.0.html