Picade console - battery power options?

Hi learned forum folks :)

I built the picade console recently. Got a nice long HDMI cable for using it with the “Big TV” but wondering, has anyone any experience of powering it with a Lithium Ion battery pack? I’m thinking something that could be used to plug the 5v Micro USB into the wall and power / charge the console at the same time but also power it on it’s own to avoid plugging it into a power source for TV’s / monitors that aren’t close to where you may be sitting with the console… I think there would be enough space inside the case for a pack - just not sure which components I would need… Any guidance please?