There's one lithium ion battery in the Soundlink Mini. It holds up to seven hours of battery life, which was enough to keep the party going and then some. I can't imagine taking this speaker outside, since its aluminum casing and fine metal mesh is so precious, but I can imagine it on the desk of some student or apartment dweller who's not quite ready to splurge on an audio system but still wants great sound that fits into a small space.
A charging cradle is included with the speaker. While it takes a bit of practice to line up the charging port with the cradle, I do love how elegantly and seamlessly the speaker fits into the dock. It keeps the cable out of the way, and it makes moving the Soundlink around after charging very simple. If you're moving to the kitchen from the bedroom, removing the device from the cradle is as simple as lifting it.