Amazon.com: A1417 Battery Only for (Mid 2012 & Early 2013) A1398 MacBook Pro - Replacement Battery for A1398 MacBook Pro 15-inch Retina (Mid 2012, Early 2013 Version) - EMC 2512 or 2673 [11.26V/99Wh] : Electronics
Apple Will Finally Replace Batteries in Mid 2012 and Early 2013 MacBook Pros
How to Replace the Battery in the 15-Inch Retina MacBook Pro: EveryMac.com