*** Prius Hybrid Battery BOOOOOOOOOOOM!!! ***

2005 Toyota Prius w 152,000 Miles * A year ago i saved a few bucks and had this guy off offer up that worked out of his garage swap a couple modules and gave life back to my Prius hybrid battery.. Well last week i had a couple modules get weak on me and called this guy again. His son took over business and didnt seem as educated but i took a chance anyway. He did the same and swapped out some modules but car didnt start. Then he swapped out a couple more. Now i had back area open and clear on a 54 degree day and i started smelling something. Me being a dumbass thought it was the brakes to cement truck in front of me. So i kept driving until i heard a hissing sound from hybrid pack. i literally had less than a mile to get to my chicks place when BOOOOOOM!!!!!!!!! i literally thought back window blew out. Then came the gasses from battery which where so toxic i couldnt breath. i literally tuck and rolled out of the car in front of two police officers who called in firetruck because fumes were so bad and hissing out of the car. The hybrid battery broke the stabilizing bars from every module ballooning and expanding beyond belief.. (see pic)

My question, what do you think could have caused literally "every" module to overheat to the point of expanding three times the size?

and no the son wasnt licensed or even incorporated. i mentioned balancing and such to him and he danced around it. and when i asked to be refunded and compensated the little punk told me i talk a lot of sh*t and to pound sand.