CANON iP110 Mobile Inkjet Photo Printer

As a portable, does this include a battery, or is it compatible with the iP90 battery pack?

Does not come with a battery. According to the manual and product page, you can get the

LK-62 Battery Kit
This kit allows you to use the Canon printer in location where a power outlet is unavailable. The kit contains a battery pack and a battery attachment. To charge the battery, load the battery pack in the battery attachment, and attach it to the printer, and then connect the AC adapter to the printer. For details, refer to the kit’s instruction manual.

The battery bundle model includes the printer, battery pack, and battery attachment. However, you may not be able to purchase this model in some countries or regions.