I wasn't able to find a battery replacement (neither 54wh or 97wh) for my Dell XPS 15 9560.
This page only shows a power companion, which is pretty useless to me:
You can contact Dell Spare Parts department at 1-877-717-3355 to obtain a battery for your xps 9560. Below are some part numbers for the different batteries that were shipped with the system.
P/N YWYV6 BTRY,PRI,56WHR,3C,LITH,SDI
P/N 5XJ28 BTRY,PRI,97WHR,6C,LITH,LGC
P/N GPM03 BTRY,PRI,97WHR,6C,LITH,SMP
P/N 5D91C BTRY,PRI,56WHR,3C,LITH,LGC