iFixit: New MacBook Pro has first 'DIY-friendly' battery replacement design since 2012 - 9to5Mac
hardware - Macbook pro 13" mid-2012 not turning on, no battery leds (battery ok) - Ask Different
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
NewerTech® : Batteries : NuPower® Battery for MacBook Pro 15" Unibody Early & Late 2011, Mid-2012 Models