The firm’s mobile division chief Koh Dong-jin said the company discovered an issue in battery cells and the smartphone itself had no problem.
Koh said the layer of plastic separating the positive and negative sides of the battery was punctured during the manufacturing process.
If the layer of plastic had a problem or was too thin, it could put negative and positive poles into contact and ignite, according to Doh Chil-hoon, a researcher at the Korea Electrotechnology Research Institute.
Following the announcement, Samsung SDI’s stock price plunged and Samsung Electronics replaced all the batteries of the Galaxy Note 7 with Chinese battery-maker ATL.
However, as the explosions continued even after the problem batteries were replaced, there has been growing speculation the smartphone design was problematic in the first place.
“(Samsung) appeared to have made rash decisions. It should have looked into the problem by looking at all the possibilities,” said Park Chul-whan, a former chief of the Korea Electronics Technology Institute’s battery research division.
Samsung’s new features of making the Note 7 dustproof and waterproof may have caused the problem, industry sources said.
“The functions block all the holes to prevent dust and liquid from coming inside. The device without holes may rapidly increase the temperature of the phone and puncture the layer of the separation,” an industry source said.
Another point of speculation is the Galaxy is using for the first time quick-charging batteries, which provide excess current to make charging faster. But, if the system has an error and keeps providing excess current even if as battery has an issue, it may cause further problems.
Further speculation is that the new phone’s high-performance software, such as iris recognition and the S Pen stylus, may be causing overloads.
“We haven’t found out the real cause of (the explosions) and we are now precisely looking into the problem,” a Samsung Electronics’ spokesperson said Tuesday.
The Samsung Galaxy Note 7 is not the only smartphone that has had problems with explosions.
Samsung’s smartphone arch rival Apple is also investigating a number of reports that iPhones have started to explode or catch fire.
According to news reports, there was an explosion of a new Apple iPhone 7 during a delivery last month. Another incident saw an iPhone 6s Plus explode while inside a student’s back pocket while in a classroom.
By Shin Ji-hye/The Korea Herald (firstname.lastname@example.org)