Samsung has finally revealed the reason behind the Galaxy Note 7 catching fire. Following the fiasco of Galaxy Note 7 and its global recall, the company conducted its own internal investigation and shared the conclusion on the Samsung NEWSROOM US.
Samsung in its press release stated that the company had examined the Galaxy Note 7’s software, hardware and related process over the past several months. Samsung along with three industry organisations, UL, Exponent and TUV Rheinland concluded that the battery caused the Galaxy Note 7 devices to explode.
There were two reasons that caused damage to the Galaxy Note 7 device. The battery casing had a design flaw. Apparently, there was no space in the battery container, causing the electrodes inside to bend when they should remain straight. The electrodes, as a result caused a deformation in the battery particularly in the upper right corner. As lithium-ion batteries comprise of one positive and one negative electrode, the deformation in any of the electrodes could deteriorate the separators and cause failure. The separators are used to avoid short circuit in between two electrodes.
The ultra-sonic welding process used to attach the positive tab caused higher than usual welding bars to be present on the positive electrode. This was the second cause to be identified during the investigation. The welding bars caused penetration of the insulation tape and the separator and led to direct contact with the negative electrode. Furthermore, the negative electrodes were not placed correctly in the battery assembly.
Samsung in its press statement said, “A short circuit within the battery may occur when there is damage to the separator that allows the positive and negative electrodes to meet within the jellyroll. Based on a detailed analysis of the affected batteries, both Battery A from the 1st recall and Battery B from the 2nd recall, we identified separate factors originated in and were specified to the two different batteries.”
The Galaxy Note 7 was reported to first catch fire in early September last year. The US Consumer Product Safety Commission made a complete recall of the Galaxy Note 7 units in the country. Followed by a global recall including Canada, Asia and throughout Europe. Samsung made a recall of almost 2.5 million Galaxy Note 7 devices globally. The crisis had an effect of 4.54 trillion Korean won ($4.0 billion) in the third quarter last year.