Ohhh, ok. At first I thought you wanted to power an electric wheel chair with solar
Ok, so first off, you'd need a solar panel that can withstand being sat at, and also perhaps things being dropped on. Otherwise, it'd be dead after first accident. Flexible panels might work for this. If your chair is flat seated, then you might be able to use a properly sized panel with tempered glass for the seat. Unless you don't plan on putting the seat with the panel. The back could also use a panel.
You could use laptop batteries for this, yes. Since you want to power small devices, you don't need to go 48V route, but 24V would suffice, as everything would be bucked down to the proper voltage. Maybe even "12v" would work (4s or 5s for this, as 3s would be too low) as long as the mppt charge controller can work in the voltage range. 24V (7s) would be more amiable for this application.
Depending on the size of your chair, you wouldn't even need to put the cells in the legs. You could have them lay flat against the underside of the seat. Would only add about 25mm to the bottom of the seat, which isn't much. Then depending on the space available, put as many in parallel as possible for the voltage your choose. The mppt controller could probably be mounted on the back of the seat to keep it hidden, out of the way, easy to get access to if need be.
I'd reserve the legs/arms for the wiring and not put cells in there.