Actually I plan to replace it myself. It is made of several PCBs that plug together, The cell is soldered in (with welded tabs). I understand few guys are in a position to do this, hopefully the maker will provide replacements at reasonable costs when the time comes (as other makers seem to be doing).
You can see the (blue) cell under the top PCB. Since there's only one it's a cell, not a battery (which is two or more cells working together).
I pack it 'medium'. It's conduction, you need firm contact to get effective heating. However, I found the perforated metal plate was causing me problems. It could lie flat enough to cut off most of the tiny holes in the plate. I found bowing it up a bit (bent in my finger tips) so it can't lie flat made the draw easier by a lot.
Enjoy your Summit.
OF