The reason why Samsung Galaxy Note 7 batteries were catching fire is to be revealed on the press conference on Sunday (January 22). The details on the results of the internal investigation by Samsung are not released to public, but several publications came ahead of the official report.
According to WSJ, the core defect, causing phones to catch fire, is the battery, which was irregularly sized, causing overheating. Manufacturing defects were also cited as one of the reasons. It turns out, that the original batteries came from Samsung SDI affiliate. Once the manufacturing defects were detected, that led to the first recall, Samsung switched to different Chinese battery manufacturers. The defects in the new batteries caused Samsung to issue the second recall and kill the production of the phone.
The recall of Galaxy Note 7 phones turned out to be public relations nightmare for Samsung, undercutting reputation of the company. The frequent Galaxy Note 7 battery fires caused Samsung first to offer replacement phones, and then recall all the phones for a refund. The total cost of the recall is estimated as $5.3 billion. As the debacle progressed, the airline passengers were first asked to turn on all Galaxy Note 7 devices when on board, and later the phones were completely banned from all flights.