Galaxy Note 7 battery explodes due to aggressive design

A beautiful and dangerous smartphone from Samsung

Samsung has invested a lot of effort and money in developing the newest flagship of the company, Samsung Galaxy Note 7, and in promoting this product. Unfortunately for the company, after the phone entered the market, everything went wrong, as planned. At the end of August, several messages appeared on social networks about the explosion or burning of phone batteries . The company acknowledged the problem, saying that it was caused by some shortcomings in the process of producing batteries. All owners of Galaxy Note 7 offered to replace their phones, strengthening the battery protection. But this did not solve the problem of ignition - the modified smartphones already began to explode.

What happened is a nightmare for any technology company. To prevent this from happening again, Samsung continues to analyze what happened. Engaged in the study of the situation and outside experts. Until November, several suggestions were made about what could be the cause of a fire. In particular, the company's engineers suggested that the layers of the battery too compressed during the production process. Another assumption is poor-quality insulation or a defect in the production of battery cells. But it seems that the problems here are not only with the battery, but also with the design of the case and components of the phone.

The company so far says nothing about this, but that the problem lies not so much in the batteries as in the design of the phone and the placement of the elements, most experts are sure. To confirm this point of view, the employees of the company instrumental.ai purchased the mentioned phone and decided to disassemble it. To ensure their own safety (and to attract attention to the photo), a fire extinguisher was installed near the workplace.
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Looking ahead, it is worth saying that the problem, as far as can be judged, was revealed . Due to design errors, the battery is sometimes squeezed during normal use of the phone.

Why does it matter? The fact is that the Note 7 battery is a Li-Ion battery of a flattened form, which consists of a positively charged layer made of a cobalt-nickel oxide and a negatively charged layer of graphite. Separates both layers of polymeric material impregnated with electrolyte. As in any other battery, the polymer layer allows ions to move freely, in the process of which current is generated. But if a positively and negatively charged layer is in contact, there is a significant heating of the electrolyte, more energy is released, the battery heats up and an explosion occurs with a fire. If you press on the battery, which is used in Galaxy Note 7, then sometimes this situation may arise. And too much pressure is not necessary.



In order to make the phone thin, the polymer was made thin, it seems too thin. As a result, the battery can start to warm up even if the user puts the phone in the side pocket of his pants and sits down, not to mention the pressure that occurs when the user puts the phone in the back pocket and sits down directly on the device. In some cases, this is enough to heat and ignite the battery. In some cases, the battery expands slightly during operation. But there is no place in the case, and the increased battery constantly tests the pressure of the case elements.

An interesting problem arises here - manufacturers seem to have come close to the border when it is already difficult to find a middle ground between security requirements and marketing. For the sake of users who like everything “the most subtle, the most productive, the most ...” technologists have to make concessions. In order to ensure the safety of the battery, the engineers of the company created a special durable "pocket" inside the case. This pocket, according to the developers, should keep the battery intact in the event of factors such as pressure or deformation affecting the phone. But due to the fact that the body was created too thin, this structural element does not help in all cases.

It may well be that in the process of developing a new phone, the company decided to update the technical process of battery production. The prototypes of the phone were tested with the batteries of the previous type, and the company simply did not have time to test the batteries in full (this takes about a year and thousands of batteries). This is one of the scenarios that have led to the current disastrous result.

Let me remind you that on September 2, the company announced the recall of all Galaxy Note 7 applicants. After the device from the “safe” party exploded right on board the aircraft, the company had to completely stop production and withdraw all of its devices.


The results of high-speed computed tomography of the lithium-ion battery cell 15 seconds before the accident (above) and 1 second before the accident (below). Source: “ In-operando high-speed tomography of lithium-ion batteries during thermal runaway ” research paper, Nature Communications 6, Article number: 6924 (2015), doi: 10.1038 / ncomms7924 (publicly available)

Probably the problem can be solved by using a smaller battery. But the company initially did not want to reduce the battery capacity for the sake of marketing. The fact is that in this case the battery capacity would be less than that of the Galaxy Note 5 and the iPhone 7 Plus.

The corporation took the risk and lost. The results were terrible. According to experts, the solution to the situation will cost Samsung about $ 5 billion dollars. This does not include reputational losses, which later may also lead to significant financial losses. After all, millions of people have learned about the incident, who will now be wary of the products of the South Korean company. It may well be that Samsung will return these devices to the market, but after all the problems with the batteries have been resolved.