I need help replacing the battery on a vector robot

I bought my vector robot brand new but his battery needs to be replaced. He only works when he's on his dock but as soon as he rolls of he shuts off, and it's a complicated because you would litterally have to take him apart to replace his battery and some how take the battery that's been soldered on to his main frame. I've seen videos of people doing it but I do not know how to solder nor would I be that smart enough to put him back together properly. Can someone please help me? Looking for people within the U.S