It’s been a while since Samsung recalled the Galaxy Note 7 and we still didn’t know the exact reason which caused the device to explode in so many cases until today. Thanks to the guys at Instrumental, who completely tore down the device to analyze as to what actually was the issue with the popular phone. 
According to the report, the main reason behind the Note 7 explosion was the aggressive design. Samsung, in an attempt to put a bigger battery in the smallest possible frame compromised on the space around the border of the battery. Shockingly, the space between the frame and the battery was less than 0.1mm at some places. Ideally, there should be at least a 10 percent gap between the frame relative to battery size. The reason behind this lies in the science of how lithium-ion battery works which is well explained in the report. 
“When batteries are charged and discharged, chemical processes cause the lithium to migrate and the battery will mechanically swell. Any battery engineer will tell you that it’s necessary to leave some percentage of the ceiling above the battery, 10% is a rough rule-of-thumb, and over time the battery will expand into that space.” – notes the report.
On top of this, normal compression caused by the device being placed in pockets is what caused the Note 7 to catch fire or explode in some cases. Samsung didn’t have enough space to put a 3500 mAh battery and a smaller battery with the same design measurements would have solved the problem. However, in a race to go a step further than the previous generation Note 5, the South Korean giant took the gamble which backfired heavily.
So what Samsung initially believed to be a fault in the manufacturing process of the lithium batteries turned out to be a fault in the internal design of the frame which leads us to a conclusion that recalling the device was in fact the right decision as the situation would have got worse if Samsung had continued to sell the device. The strange fact is that Samsung couldn’t find out the exact cause for the issue after the first round of recall. Nevertheless, the Galaxy Note 7 episode seems to be truly behind the firm now and we hope Samsung along with other companies has learnt a hard lesson. When it comes to safety Murphy’s law rules, so stay away from risks.