The explosion of smartphones often regarded as an accident, but the same chemical reactions underlying the battery life can make them prone to fire. Samsung had its own bitter experience, the victim of a recent campaign for the recall of defective devices, – in our case – its new smartphone Galaxy Note7, due to the fact that its gloomy batteries exploding.
When gloomy batteries exploding, most often wine producer, negligent otnёsshegosya to check components on fire. Exploding batteries may be the result of actions too impatient companies in their desire to squeeze the last drop from existing technologies. Since our screens are becoming more and smartphones, each time getting more powerful, they need more energy, but many of us are not willing to sacrifice the time of the device and fast charging.
According to Linden Archer (Lynden Archer), scientist and materials scientists from Cornell University (Cornell University), we have already reached almost 90% of the maximum battery life of the theoretically possible for lithium-ion batteries, so producers in various ways trying to expand beyond the capabilities just to add at least little energy. “It has become something of an arms race, where every smartphone manufacturer wants to get the highest battery life battery”, – he says. – “This is the trend in the production of more and more increases the tendency to excessive load on the battery, so all of these examples of failures in the work are becoming more common.”
Samsung Galaxy Note7 review explains the fact that in some devices, the two parts of the battery, which under no circumstances should not have been in contact, began to communicate with each other. In fact, there are many common ways to destroy the lithium-ion battery, and it usually is because we constantly demand too much from our devices. (Batteries are lithium-ion type is almost universally used in smartphones and various electronic gadgets. The engineers used lithium because it is lightweight and can hold a large amount of energy).
As we reported earlier, Samsung emphasized that the problem of the battery posts are less than 0.1% ( 24 devices per 1 million ) of the total units sold; while there is no doubt that the global review – it’s more than just a small hitch for the consumer electronics giant. Note7 came just a few weeks ago and was met with mostly positive reviews .
No less important is the fact that Samsung has managed to create a stir in the smartphone market in just a few weeks before Apple launched its long-awaited new iPhone. Now, the successful launch of sales of Samsung has been marred by bombings batteries.
To understand what makes the battery safe, useful to know how they work. There are two electrodes or electrical conductors disposed on opposite sides of the battery. One electrode comprises positively charged ions, and is called the cathode. The cathode is filled with lithium (to be precise nanostructured cathode material (lithium-iron-phosphate LiFePO 4)) and that it is stored in the “fuel” the battery. The opposite electrode contains negative ions and is called the anode.
During charging, lithium ions move from the cathode to the anode. When the battery is in operation mode, the lithium particles are moving in the opposite direction. The space between the electrodes is filled with a chemical called an electrolyte that conducts current, facilitating easier movement of ions between the two electrodes. Despite the fact that the ions have to move from side to side, the anode and cathode themselves should never touch each other, otherwise, they will redirect the energy of the electrolyte. To prevent this phenomenon, battery manufacturers place separators between them.
The cause of the incident with Galaxy Note7 steel separators incorrectly chosen, whereby both electrodes began to touch each other (turned out to be short-circuited). “This is the worst option of all possible errors since it can certainly cause a fire or even an explosion,” – says Archer. When the electrodes are in contact, all the energy generated is pumped into the accumulator and goes directly into the electrolyte contacts the electrodes in place.
It is worth recalling that the electrolyte itself is not very stable and is intended to improve the conductivity of the ion flux, which also leads to an additional uncertainty. When high heat – whether due to contact of two electrodes, or, for example, due to the high-temperature environment – this may cause the electrolyte reacts with other chemicals and gas is emitted, thus More releases more heat. Whenever chemicals react to emit gasses, more and more heat, the temperature begins to rise faster and faster. This creates an uncontrolled positive feedback (the so-called “thermal dispersal of the battery”), which may cause a fire.
That is why many smartphones are automatically switched off at high temperatures. But there are other reasons, because of which are the explosive battery. They also may fail when charged above the set limit or charge the battery too quickly.
Overcharging batteries can be compared to filling a bucket with water. No matter how fast you lёte important not to pour too much, otherwise the bucket is full. In the case of battery overcharging happens when too many passes in lithium anode. This does not mean that you risk overexposing the phone, leaving it connected all night – most batteries provided automatically to prevent overcharging. More likely, it is the manufacturer’s mistake, which may occur when the circuit is designed to prevent this situation, is faulty.
Shterengarts Dan (Dan Steingart), a professor at Princeton University, compares the battery with a rubber band: when you charge the battery, you stretch the tape; when using it – let go. Like a rubber band may rupture if it is too much to stretch too much energy on one side can destroy the battery.
Based on the foregoing, the issue of what happened with the Galaxy Note7 lies in excessive speed. This means that the manufacturer has tried to set too high a charging rate for the so-called “quick-charging technology”, which is a danger to the battery. (Although in theory, the problem should not be here, the Samsung has its own arsenal of quick-charging technology). If the charger for some reason is not compatible with the battery, the battery can also close. This can be avoided by making sure that the charger and battery designed to work together (perhaps here it is worth remembering the incident with a Chinese flight attendant who died from an electric shock during the charging iPhone uncertified memory).
the level of excess or too high a charging rate can lead to a problem called “plating”. Imagine that the battery – it is two trays out of the eggs. Lithium ions must be run from the cell into the cell between the two trays to be stored securely inside – says Shterengarts. If you charge the battery slowly in lithium have time to find their place in the cells of the tray until it is moved back and forth. But too fast or too much charge the lithium begins to settle on the outside of the egg tray, and later on these deposits. Over time, each time you recharge your gadget, Li starts to be postponed ( “pan out”) on itself and forms needle-like structures called dendrites, which can cause an internal short-circuit the battery.
The latter, quite common case of failure happens when companies try to make more capacious batteries store more energy by increasing the voltage. Voltage is a measure of the electromotive force. Imagine that voltage – a height waterfall, while current – the amount of water. The higher the voltage, the greater the battery power so the manufacturers try to “inflate” it is added to the lithium elements such as nickel. But again, the higher the voltage, the higher the probability that the electrolytes due to such actions can mix that will lead to their fire.
Some scientists are working to create a special type of electrolyte which will not easily ignite. “These electrolytes, called” ionic liquids “require much more heat to start to give off flammable gas”, – says Moganti Surya (Surya Moganty), a chemical engineer and Chief Information Technology Officer of the company Nohms Technology. “Often they are much safer, but there may be problems with battery lifetime”, – he says.
However, while these technologies are not available, most of us are stuck with lithium-ion batteries. “The fact that these works are” a miracle of engineering, “- says Shterengarts – will not solve the problem of instability of the device. All that can accommodate as much energy, and at the same time you can potentially get all the energy for a few minutes, to be considered as a potential bomb no matter from which it is made, “- he adds.
Battery technology is constantly evolving, but not as rapidly as our desire for faster charging and longer battery life in one package – and this is a problem that must lie on the shoulders of producers who are obliged to keep this in mind and to protect us from our own runaway desires.
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