It is most likely glued together. I opened a battery for my HP-XE3 once, it was not easy to get it opened and when I finally did, I could not get it to fit inside the computer any more. You will probably destroy the plastic if you try to open it.

I'd like to try the same thing.  Did you have any success opening the battery?  If so, how did you do it?

Dell Inspiron 8200, BIOS A11, 512KB L2 Cache
Windows XP Professional, SP1
1.7GHz Intel P4-M
DIMM_A: 512MB PC2100 DDR KingMax
DIMM_B: 512MB PC2100 DDR KingMax
Hitachi Travelstar , 60GB, 7200rpm
Samsung 15" SXGA+, 1400x1050
64MB ATi Radeon Mobility 9000
Toshiba DVD-ROM SD-R2002
Dell TrueMobile 1300 MPCI Wireless

I'd like to try the same thing.  Did you have any success opening the battery?  If so, how did you do it?Dell Inspiron 8200, BIOS A11, 512KB L2 Cache
Windows XP Professional, SP1
1.7GHz Intel P4-M
DIMM_A: 512MB PC2100 DDR KingMax
DIMM_B: 512MB PC2100 DDR KingMax
Hitachi Travelstar , 60GB, 7200rpm
Samsung 15" SXGA+, 1400x1050
64MB ATi Radeon Mobility 9000
Toshiba DVD-ROM SD-R2002
Dell TrueMobile 1300 MPCI Wireless

Nice idea, i reckon you have to carefully split the battery in half along the joining part but you might damage its shape. You are most probably better off buying the space saver module which is an empty piece of plastic weighting nothing and costing nothing either. One came with my i3800.