Samsung Electronics on Monday blamed batteries supplied by two manufacturers for the overheating and even explosions of some Galaxy Note7 phones, as it tried to provide a long due explanation for the issues surrounding the smartphone.
The announcement by the company, a day ahead of it reporting its fourth quarter results, had experts from TUV Rheinland, Exponent and UL stating that internal manufacturing and design defects of the batteries, including missing insulating tape in some cases, and not the design of the phones were responsible for the battery issues.
The negative electrode windings in the battery of an unnamed “manufacturer A,” who first supplied the batteries for the Note7 phones, were found in some cases to be damaged and bent over because the cell pouch did not provide enough volume to accommodate the battery assembly, said Kevin White, Exponent’s principal scientist, at a press conference that was webcast.
There were signs of internal short circuit at different locations of the cells from five of the damaged devices, said Sajeev Jesudas, president of the consumer business unit of UL. He also pointed to deformation of the upper corners of the batteries, missing insulation tapes on the tabs, and the use of thin separators as some of the factors that could contribute to a short circuit.
After incidents were reported on the field, Samsung turned to another supplier, referred to by the company as “manufacturer B.” But welding defects in “some incident cells were found to be tall enough to bridge the distance to the negative electrode foil,” raising the possibility of short circuits and self-heating, White said.
Samsung turned to Amperex Technology in Hong Kong to supply batteries for the replacement Note7 phones after issues were reported with batteries supplied by affiliate Samsung SDI, the Wall Street Journal reported, citing people familiar with the matter.
Samsung’s team of investigators checked the Note7’s features such as fast charging, water resistance and its newly-introduced iris scanner for a possible role in the explosions but found those had not had an impact, said D.
