Battery lattepanda Alpha ?

Hello everyone, like many users, I'm looking for a battery to connect hard the dedicated port. In order to move my Lattepanda Alpha without turning off this one. I could read that the port to use is the same as that of (cube i8 but the batteries are 7.4v). This battery should be recharged if the pc is mains. Do you have a solution ? thank you in advance for your help.