Samsung investigation reveals two manufacturing faults behind Galaxy Note 7 fiasco

Casings too small for electrode assembly, and punctures in component separating positive and negative electrodes found

Two separate battery issues were the cause of the fault in Samsung's Galaxy Note 7 smartphone, the company's own investigation has revealed.

The four-month-long investigation saw 700 engineers and researchers test 200,000 Galaxy Note 7 smartphones and 30,000 batteries. The company said that it had inspected both software and hardware, with the only faults being found in the batteries themselves.

"To find the cause of the Galaxy Note 7 incidents, Samsung examined every aspect of the Galaxy Note 7, including hardware, software and related processes over the past several months," the firm announced in an official statement.

"Samsung's investigation, as well as the investigations completed by three independent industry organisations, concluded that the batteries were the cause of the Galaxy Note 7 incidents."

Two separate battery flaws were to blame.

The first, as expected, related to how the Galaxy Note 7's original batteries were manufactured, with the company admitting that the batteries' casings were too small to safely fit the electrode assembly inside, which lead to short-circuiting.

Samsung didn't name and shame the third-party company it blames for the issue, but reports last week suggested Samsung SDI manufactured the first set of faulty batteries.

The company went on to admit that its second source of batteries had a different manufacturing defect that led to the same explosive result.

In this case, the fires were caused by punctures in a super-thin component that separates the positive and negative electrodes, and faulty insulation. This second batch of batteries was provided by Hong Kong's Amperex Technology Ltd.

However, Samsung's mobile president DJ Koh said that the ultimate responsibility falls on Samsung itself, for signing off on the mis-manufactured batteries ahead of the Galaxy Note 7's launch.

Koh announced a new eight-step inspection process that will be carried out on all future Samsung smartphones, including the Galaxy S8: a durability test, visual inspection, x-ray test, charge and discharge test, leak detection test, disassembling test, accelerated usage test, and battery voltage comparison test.

"To make an innovative Note 7, we set the target specification for the batteries, and feel a grave responsibility for failing to test the battery design and manufacturing process before launch. We will put safety and quality first going forward."

Out of 3.06 million Galaxy Note 7s distributed to the market, 96 per cent have been recalled globally, Samsung added.