I have posted a link to a russian video that shows very clearly how to take the n9 apart and one of the steps is removing the battery. I get that you wont understand the language and the video isnt as detailed as maybe wanted by some thats why i have also posted a link to my thread at xda which tells you in every little detail how to take apart the lumia and also has a 20 min video(not mine) that is in english and explains everything very very well. Before everyone starts going crazy that im talking about the lumia, the two phones are almost identical when it comes to this. So you can combine the watching of the russian video and my notes from the lumia and you'll have your guide.

once again: russian n9 video-
http://www.youtube.com/watch?v=mSJtUbnM46E

my thread with another video and all the details and instructions you'll ever need:
http://forum.xda-developers.com/show....php?t=1526844