This is my fairly new Dell XPS 13 (9360), 7 months old. The battery stopped working so I ordered a new one to replace it.
Disassembly / reassembly as specified in the IFIXIT article worked exactly as specified. I removed the original battery, opened up the package I had ordered with the new battery, and lo and behold, they had sent me a battery for a different machine, possibly an XPS 15. It was too big and NOT the same battery at all. So I reseated and attached the original battery, reassembled the back casing of the laptop, and voila - it worked and I didn't need to replace it after all. I'm now in the process of swapping the battery sent for the proper model.
If I did this again, I'd try removing and reseating the old battery before bothering to order a replacement. In the old days, whether with operating with server / desktop components (which were simple to access and reseat), or checking out the old fashioned click out/in "user replaceable" batteries, this would have been a no-brainer habit. Doing it on a thin, small laptop these days, having to deal with over a dozen tiny screws and tiny sockets and connectors, makes it tempting to skip reseating, assume the component will need replacing, and thereby save at least one disassembly/reassembly cycle. This was exacerbated by this being a fairly new and expensive laptop which is still under partial warranty, so didn't want to screw anything up (no pun intended). Lesson learned ...