laptop charge

Hello! I managed to get this box from work, and I’ve decided to turn it into a portable PS2. The main question right now is: what am I missing? I know I’ll need batteries, and as you can see, there’s quite a lot of room inside the case. I’m assuming I’ll also need a charging module...

My goal is to achieve automatic & continuous charge and play when an external PSU is connected. I’ve been digging up peoples’ solutions, and there are some sophisticated ones (i.e. USB-C PD)! I’d like to implement a simpler solution using dedicated Power Path ICs. Since what I want is...