The Battery used in all models of AIBO is a Li-Ion (Lithium Ion) rechargable pack.
All AIBO models recharge the battery internally, although some AIBO Energy Stations are capable of charging another battery independently of the AIBO. There is the ERA-301P4 Portable Charger unit available for the ERA-201B1/ERA-301B1 and ERA-7B1 battery types, however, no specific portable battery charger is available for the ERA-110B battery. Although, there has been some success with the use of camcorder battery chargers, specifically the "Hahnel Twin V102"
There are many different types of battery available, and some are specific to particular models.
Failure of battery packs can be gradual or sudden manifesting as a shorter run time, complete lack of power or refusal to charge. Repacking of failed packs has been attempted among the community however at the time of writing this article, this process has produced little success.