My answer to What is wrong with Samsung's Note 7 battery?
Answer by Allen He:
Why did Galaxy Note 7 catch fire even explode?
The explosion was triggered by the battery heating and fire while charging, according to the description of the victim of Galaxy Note 7 battery explosion, the charger and charging cable he used were not genuine, he applied an old Type-C adaptor which was connected with an unbranded cable, some bloggers deduced a conclusion that unmatched charger and cable caused Galaxy Note 7 battery explosion, hence, charging with original Samsung charger and cable is highly recommended.
Is that all? Probably not. Citing an unnamed company official, it is said that Samsung’s investigation found that faulty batteries caused the phone to catch fire. The number of the Galaxy Note 7 phones with a faulty battery accounts for “less than 0.1 percent” of the products in the market. Some shipments are being delayed due to additional tests being conducted for product quality. People started to worry that the Galaxy Note 7 on hand hit that 0.1 percent.
Samsung officials did not reply to questions about how Samsung determined which phones are deemed safe and which require further testing. It did not say if those phones are different from the ones sold in South Korea. As the latest iteration product of Samsung, several Galaxy Note 7 battery explosion cases happened within such a short period after the launch, it created a perfect chance for the upcoming iPhone 7 to take the lead again.