After months of speculation as to the reason behind the Note 7’s tendency to spontaneously combust, Samsung has finally concluded its investigation of the issue. Based on the results Samsung has gathered, the Korean company officially confirms that battery issues are the reason why the original batch and replacement batch of smartphones malfunctioned as they did.
With the original batch of Note 7, the main cause of the battery failure is due to a design flaw that is located at the upper-right corner of the smartphone.
Due to the way the Note 7 is designed, the positive and negative electrodes could come into contact with each other should the protective layer that separates them gets damaged. If the electrodes were to come into contact with one another, it would cause a short circuit which would ignite the battery.
As for the replacement batch of Note 7, the fault lies with the manufacturing of the battery. In Samsung’s haste to push out the replacement Note 7 to the public, some of the batteries that were designed for the replacement models came with a welding defect.
This welding defect damages the insulation tape that separates the positive and negative electrodes, allowing both electrodes to come into contact with one another and short-circuiting the battery. In some cases, Samsung even found that there was no insulation tape to separate both electrodes from one another to begin with.
In order to prevent future Samsung phones from exploding like the Note 7 did, the company has announced that it will be implementing changes to its device manufacturing process.
Some of the changes include assigning teams to conduct the final checks for each device’s core components, as well as an eight-point test of the battery that ranges from visual inspection to x-ray inspection and even a full disassembly
Source: Android Authority