The Samsung Galaxy Note 7 was supposed to be a hit. It followed the well-received Samsung Galaxy S7, which had been dubbed “the phone to beat in 2016.” Instead of building on earlier successes, Samsung had to recall the Galaxy Note 7 after receiving at least 92 reports of the phones catching fire in the United States. In some cases, these fires caused injuries and property damage.
You may be wondering what is causing the phones to explode. Samsung’s official statement says that the issue is related to the phone’s battery cells overheating. Without more information from the company itself, we can’t know exactly how the overheating process works. However, scientists have a pretty good idea.
The Galaxy Note 7 uses a lithium-ion battery, with layers of positive and negative electrodes divided by thin separators. While the phone is charging, the lithium ions are carried from the positive electrodes to negative electrodes through the electrolyte, a liquid or gel that conducts electricity. The opposite occurs when the battery is being used. Lithium-ion cells are great for smartphones because they can store a lot of energy in a very small space.
However, the way these batteries are constructed can also cause some serious problems. There seems to be a manufacturing defect in the Samsung phones with the “battery management system,” which monitors electrical current and stops the battery from overcharging once it is fully charged. If this system fails, the phones will overcharge if they are plugged in too long. This creates excess heat, which can tear one of the separators and cause the positive and negative electrodes to come into contact, creating a short circuit. The electrolyte used in lithium-ion cells is highly flammable, and has a high likelihood of catching on fire in the event of a short-circuit.
The resulting fire can cause serious damage to the people or possessions around the smartphone. Samsung is now facing a lawsuit from a man whose Galaxy Note 7 allegedly exploded in his pants pocket, causing second-degree burns on his thigh. As the number of reported incidents rises, Galaxy Note 7 users are strongly encouraged to trade in their phones for a free replacement phone that doesn’t have the defect. This manufacturing mistake is expected to cost Samsung hundreds of millions of dollars. The large amount of media coverage of the exploding smartphones has also created a PR nightmare for Samsung, which could potentially lose even more customers as consumers turn to other companies.