The nightmares of sudden Galaxy Note 7 explosions with shards of glass flying around still plague Samsung. This flagship smartphone was pronounced dead well over a month ago but the Korean behemoth is having trouble identifying the cause of the humongous number of fires and blasts.
But a fresh report from the manufacturing company Instrumental believes to have discovered the real reason behind all the explosions. After performing a teardown of a defected Galaxy Note 7, the manufacturer found that Samsung has crammed the internals within the device. Thus, the design of the device is fundamentally flawed and the battery doesn’t have enough breathing space or room for error.
The researchers at the manufacturing facility found that the phone’s design is enough to compress the battery during normal operation – no external force is required for the same. To understand the primary cause of the explosions, we first need to know the internal structure of the battery. The report describes it as under:
The Note 7’s lithium-polymer battery is a flattened “jelly-roll” consisting of a positive layer made of lithium cobalt oxide, a negative layer made of graphite, and two electrolyte-soaked separator layers made of polymer. The separator layers allow ions (and energy) to flow between the positive and negative layers, without allowing those layers to touch.
Now, the report says that it the two layers come into contact with each other then the energy flowing goes directly into the electrolyte. This heats the same and caused more-than-required energy to flow through the battery – causing it to go kaboom. The polymer separator layers enable the two layers to not come in contact and protect the battery.
Samsung stated that these separator layers may have been thin to start with due to aggressive manufacturing parameters. Add some pressure due to normal mechanical swell from the battery or accumulated stress through the back cover (e.g. from being sat on in a back pocket), and that pressure could be enough to squeeze the thin polymer separator to a point where the positive and negative layers can touch, causing the battery to explode,
reads the report.
When batteries are charged regularly, they tend to swell a little over time. The report says that around 10 percent extra space is required but the Galaxy Note 7s battery completely accommodated its 5.2-millimetre-deep pocket. This left almost negligible space around the edges and thus, the risk of explosions were heightened.
It further states that the condition would’ve only worsened if the Korean giant, Samsung, hadn’t recalled all devices from the market. It could’ve included a smaller battery during the recall but new battery technology would be required to cram that into the said design of the phone. The report also adds,
Looking at the design, Samsung engineers were clearly trying to balance the risk of a super-aggressive manufacturing process to maximize capacity, while attempting to protect it internally. Samsung took a deliberate step toward danger, and their existing test infrastructure and design validation process failed them.
Samsung still hasn’t released any official comment for the cause of repeated Galaxy Note 7 explosions. But this will surely give it more insight into where to look for the error it made. #RIPNote7
