Why Note 7 exploded, Samsung got the answer

Samsung revealed about why Note 7 batteries used to burst. In almost less than 3 months, Samsung recalled about 96% Note 7 from all around the world. 2 million Note 7 devices were sold in the last year. For the last three months, Oct, Nov & Dec, around 700 researches are investing on the Samsung note 7 battery explosion. 200000 note 7 devices were tested and 30000 batteries were attempted to replicate the reason behind the explosion. Everything were tested strating from wireless charging to USB Type C adapter.

What is the there behind this..??
The answer came out on 22 January, 2017 when Samsung Note 7 researches found that there were battery designing problems. And with that problematic design only, the batteries were manufactured. No one noticed about it. The batteries that were manufactured before August, 2016, were exploded, but the batteries manufactured on and after august, 2016, were all perfect. No explosion complain came. Both batteries were of same capacity i.e 3500mAh 13.48W 1|CP6/39/38

Nominal Voltage was : 3.85 V and Charging voltage was : 4.4V

The first manufacturer of the batteries was Dongguan ITM Electronics Co. Ltd.., a company in China who designed and manufactured those defective batteries.
The second manufacturer of the batteries was Ningole Ameperex Technology Limited.

Samsung Next Level Measures :

How the design made the negative electrode curved and touched each other which resulted in explosion and fire

    Durability Test – Conducting additional durability tests, including battery nailing, stress testing with extreme temperatures and overcharging tests.
    Visual Inspection – Visually checking the battery to compare it with samples confirmed to be in accordance with standardized criteria.
    X-Ray Test – Running X-ray tests to inspect any possible battery issue such as a deflection of the electrode, which we found to be one of causes of the Note7 issue.
    Disassembling Test – Disassembling the battery cell to perform a detailed check of the overall quality, including the battery tab welding and insulation tape conditions, which we found to be an issue with Note7.
    TVOC Test – Performing a test to detect leakage at the battery component and complete device levels.
    ΔOCV Test – Checking voltage change in a normal temperature.
    Charge and Discharge Test – Applying new large-scale charge and then discharge tests to all of the devices, which initiated with their investigation.
    Accelerated Usage Test – Engaging in 2 weeks of real-life consumer usability scenarios, which we were able to shorten to a five-day test period.