Had a bit of fun with some LiPo batteries today. I had an opportunity to purposely burn up some LiPo cells today to see if a simply aluminum enclosure can contain the heat generated when they let loose.
I had 4 Turnigy nano-tech 4400mah 7S Batteries in the box, connected to create a single 8800mah 14S pack. Starting with the cells fully charged, I pushed 4 amps of current into them for a little over an hour before they finally gave up. It hit 72 volts right before everything went wrong with the cells. Impressive to say the least… my money was on them failing much sooner. Temperature inside the enclosure went over 1370 degrees Celsius (the limit of my data logger) for a few seconds before settling down to 900 degrees for 5 or 6 minutes. It took about 30 minutes for it finally the cool down to 400C. The cell closest to the camera looks like it blew first and hardest… it managed to blow a penny sized hole in the aluminum at some point. That side of the enclosure was bent and cracked from the heat also.
The initial smoke is caused by the first cell letting go. The second blast which hits the camera is the other three cells from what I can see. The next test will be with 8 cells and a stronger box. 😉