After months of investigation since it pulled the Galaxy Note 7 from sale, Samsung today detailed the cause behind the handset catching fire. The investigation was carried out by Samsung’s own high-level engineers and three other third-party investigators: UL, Exponent, and TUV Rheinland AG.
Samsung notes that it investigated over 200,000 units of the Galaxy Note 7 but did not find any issue with its internals. It examined various aspects of the device including its water-resistance capabilities, USB-C port, fast charging, iris scanner, software, and more.
The cause for the battery fires was ultimately narrowed down to faulty batteries supplied to Samsung from two of its suppliers. The initial Galaxy Note 7 units shipped with ‘Battery A’ which had an abnormality in their top-right corner where the negative electrode was deflected. The tip of the negative electrode was also located in the wrong area in the curve. These issues led to the positive and negative electrode of the battery coming in contact with each other thereby causing a short circuit.
As for ‘Battery B’ which were used by Samsung in the replacement Note 7 units, they were found to ship with “high welding burrs on the positive electrode” that led to the protective layer and the negative electrode coming in contact with the positive electrode. It also found that a number of batteries were missing the insulation tape completely.
Instead of blaming its suppliers, though, Samsung accepts that it was the company’s responsibility to check the batteries properly for any fault. So, going forward, the company has announced an 8-point battery check that will ensure the batteries used inside its devices go through a rigorous safety check which includes a durability test, X-Ray, disassembling, visual inspection, charge and discharge, TVOC test, Delta open circuit voltage test, and accelerated usage test. It also announced multi-layer safety measures protocol for every component that will be used in its devices going forward, including adding new brackets around the battery for protection.
Samsung also confirmed that it will not be launching the Galaxy S8 at MWC this year. While the company’s mobile chief did not provide any timeframe, the handset is rumored to launch in April. After rushing the Galaxy Note 7 to the market to beat the iPhone 7 and the battery fires that followed, Samsung sure has wisened up and is taking its own time to ensure something like this does not happen again in the future.