Samsung blames two separate battery faults for Galaxy Note 7 fires

Tests on tens of thousands of devices found that both original and replacement batteries were responsible for the phones bursting into flames

Samsung has blamed lithium-ion batteries for causing its Galaxy Note 7 mobile phones to overheat and catch fire, a fault that led to the global recall of millions of devices and damaged consumer confidence in the worlds biggest maker of smartphones.

At a press conference on Monday, Samsung officials said exhaustive tests on tens of thousands of devices and batteries had ruled out any problems with the devices hardware or software.

But, it added, internal and independent investigations had concluded that batteries were found to be the cause of the Note 7 incidents.

In the case of the original battery, the casing was too small, causing it to short-circuit and ignite. It was replaced with a battery that had a different manufacturing defect but led to the same result.

Koh Dong-jin, the head of Samsungs mobile business, told reporters in Seoul: We sincerely apologise for the discomfort and concern we have caused to our customers.

The company said there would be no fire risk involving future devices, including its forthcoming S8 smartphone.

Samsung infographic showing the problems with the first type of battery in Galaxy Note 7 phone. Photograph: Samsung

We are taking responsibility for our failure to ultimately identify and verify the issues arising out of battery design and manufacturing, it said in a statement. We have taken several corrective actions to ensure this never happens again.

The South Korean conglomerate promised to reform its production and quality controls to prevent a repeat of the incident: We look forward to moving ahead with a renewed commitment to safety. The lessons of the past several months are now deeply reflected in our processes and in our culture.

Samsung was forced to recall more than 2.5m Note 7s in September after reports that they were overheating and catching fire. The crisis deepened when it emerged that replacement phones equipped with batteries from a different supplier were experiencing similar problems.

The company permanently ended production of its flagship smartphone in October a move that is expected to cost the company an estimated $5.3bn in lost profits.

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