Dear Luis, I would have your battery cable checked and probably replaced. If it is that hot to the touch, it is worn and creating some related problems. In my '01 C70, my independent Volvo mechaninc replaced my positive battery cable because it was very hot and worn and the car only has 40,000 miles. Also, my mechanic replaced the cable that connects from the fuse box as it also was extremely hot and worn.
The car now runs much better and I believe it was the replacement of both cables. Perhaps you have a good indy Volvo mechanic in Albuquerque.
Good luck, Fred.