It remains for us to really know what the real problem has been what has the Galaxy Note 7 had, since at first the Korean manufacturer said that it was the batteries, but when replacing new Note 7 they found themselves again with exploding batteries. The mystery continues, although now some light has been shed on where the shots could go ...
The batteries that Samsung uses in its smartphones are taken to tests in a laboratory that is owned of the company itself. While testing to make sure its phone batteries are certified by the American wireless industry group, the CTIA, Samsung's certified lab is inside its own facility, unlike Apple and Lenovo, which receive those tests by third parties.
La CTIA audits those third-party labs to ensure that the personnel are qualified, that the tests meet the standards, while checking that there is no undue influence from the manufacturers.
The batteries are tested without being assembled in the device, as well as when it is already located inside. The testing process focuses on how the battery behaves when it is charging or while on a call. The batteries are also put at very high temperatures to simulate the summer heat and check for opportunities where you can experience spikes from overheating.
The Korean company is still investigating the real problem for the Note 7 to explode. The device has used batteries from various manufacturers, including Samsung's own SDI. And it is that when the recall for substitutions was made, Batteries manufactured by ATL included, which did not experience the same problem, which also resulted in the devices exploding again.