There's a CR-2032 lithium battery inside -- yes, you can replace just the battery.  Just wrap the leads tightly in dielectric tape (soldering or heating not recommended -- the battery is not going to stand up to heat without dramatic effect).  
[IMAGE] I have the laptop open to clean out dust and do new thermal paste. I want to replace the CMOS battery, but it's a sealed unit. The battery is covered in plastic with wires exiting from the plastic "envelope". Is it possible to open it up and replace with a standard coin cell battery, connecting the wires to the bare metal battery? Or, must I buy one of those sealed units like what I removed?
Inspiron 14 N4050: replace CMOS battery (a.k.a. BIOS battery) - sealed