Samsung has pinned the blame on its exploding Galaxy Note 7 phones on two separate problems with the handsets’ lithum-ion batteries — one problem affecting the first units the company released, and a second issue affecting the replacement units Samsung rushed out.
At a press conference earlier today, Samsung officials said the original battery casing was too small, which caused it to dangerously short circuit.
The second battery replacement, after Samsung recalled more than 2.5 million of the handsets, had an issue caused by punctures in a component separating the positive and negative electrodes, along with faulty insulation.
As part of the investigation, 700 Samsung engineers reportedly carried out tests on 20,000 fully-assembled Galaxy Note 7 handsets and over 30,000 batteries.
“We are taking responsibility for our failure to ultimately identify and verify the issues arising out of battery design and manufacturing,” Samsung said in a statement. “We have taken several corrective actions to ensure this never happens again.”
Samsung’s exploding Note 7 handsets were one of the biggest tech stories of the last year, and one of the biggest botched product launches in mobile phone history. Soon after the initially-celebrated handsets were released, reports started to circulate about their tendency to burst into flames.
It didn’t take long before horror stories started to emerge, like the Note 7 that torched a family’s jeep or the one which caused the evacuation of a Southwest Airlines flight after a passenger’s Note 7 emitted a thick grey-green smoke and burned a hole in the plane’s carpet.
Samsung issued a worldwide recall, only to find that the replacement units it had issued also caught fire. Ultimately, Samsung cancelled the device, bricked the remaining units, and issued a full page apology in the newspaper.
A previous report from Instrumental, placed the cause of failure for the Note 7 on too little space being provided for the device’s battery to expand into. The widest gap between the Note 7 battery and its case was reported to be 0.5mm, while at one point it measured less than 0.1mm.