Samsung used unsafe design for Note7

Samsung likely deliberately forewent safety for aggressive innovation in the design of the discontinued Galaxy Note7 smartphones, a decision that blew up in their faces when the devices’ batteries started exploding, according to Instrumental Technology.

The hardware design consulting company recently conducted a teardown of a Note7 device. The company discovered that design of the device did not allow for a required ceiling above the lithium-polymer battery, which “any battery engineer” can attest is necessary as a safety measure.

Lithium-polymer batteries are designed to allow energy to flow between positive and negative layers, but if those layers come into contact, energy flows directly into the electrolyte, overheating it and typically causing an explosion.

The batteries naturally expand over time, and accumulated pressure on the back of a device, such as that caused by sitting on a phone in a back pocket, can increase the risk of the positive and negative layers coming into contact.

Instrumental Technology said this is the reason for the required ceiling above the battery, which as a rule of thumb should be 10% of the size of the battery.

“Our two-month-old unit had no ceiling: the battery and adhesive was 5.2 mm thick, resting in a 5.2 mm deep pocket,” Instrumental Technology CEO and founder Anna-Katrina Shedletsky said.

“There should have been a 0.5 mm ceiling. This is what mechanical engineers call line-to-line — and since it breaks such a basic rule, it must have been intentional. It is even possible that our unit was under pressure when we opened it.”

The design indicates that Samsung attempted to mitigate this risk by housing the battery within a CNC-machined pocket to protect the battery from being poked by other components of the device.

If this was the reason for the exploding battery issue that led to a global recall, it would explain why the decision was made to terminate the entire line rather than making alterations — it would require a major redesign.

While the issue could have been avoided by using a smaller battery, this would result in the Note7 having a shorter battery life than its predecessor and the rival iPhone 7 Plus, Shedletsky added.

Apple is currently grappling with its own faulty battery issue, although this is related to the previous-generation iPhone 6s and is not a safety issue.

The company recently announced that “a very small number of iPhone 6s devices may unexpectedly shut down” as a result of a faulty battery. This follows reports of some iPhone 6s smartphones repeatedly shutting down at around 30% charge.

The company is providing an online tool to check whether their devices' serial numbers fall within the range of affected devices, and will replace the battery free of charge for devices within this range.

But some Chinese iPhone 6s users are reporting that devices outside the range have been affected as well.

Apple responded stating that the company will be including a diagnostic tool in an iOS software update that may help the company improve the algorithms used to manage battery performance and trigger shutdowns to protect the device’s electronics. Any improvements can be delivered in future software updates.

Photo credit: Instrumental Technology