This is from last year, but some may have not seen it yet. It means a brand new free battery if you are affected:

http://support.lenovo.com/us/en/documents/hf004122

Executive summary: units shipped approx Oct 2010 and Apr 2011 incl: ThinkPad T410, T420, T510, W510, X100E, X120E, X200, X201, X201s Series Edge 11, Edge 13, and Edge 14 Series

Must match battery serial #'s against the web site.