One article understands the explosion principle and charging error of mobile phone lithium battery

In order to successfully expel a lithium battery, lithium atoms or lithium ions must be directly in contact with oxygen. The only way to create such conditions is to violently damage the battery casing (such as external force, fire, etc.), overcharge or short circuit, etc. Several, of course, the use of cottage inferior batteries are also included.

Let's see how the battery charges lithium. Initially, lithium atoms were stored only in positive and negative electrodes, separated by electrolytes or electrolytes between the two poles (lithium ion batteries are electrolytes, lithium polymer batteries are non-liquid electrolytes). In this case, the relative ratio of lithium in the poles is relatively stable. Especially in lithium polymer batteries, lithium exists in the form of a compound, so even if it is exposed to oxygen, it is not easy to directly explode.

When charged or discharged, the situation in the battery changes: the lithium atom in one electrode loses one electron, becomes a lithium ion, and passes through the middle electrolyte or electrolyte, enters another pole, and becomes an atomic state again. The most dangerous situation is precisely in the process of lithium ion migration. Here's how you torture these lithium-ion or electrolytes.

1, short circuit

Short circuit, I'm sure everyone understands how it works. After the lithium battery is short-circuited, the electrolyte or electrolyte will begin to accumulate heat. At first, a small amount of heat does not seem to be much of a problem, and once the heat reaches a certain level, the electrolyte will begin to expand, and the electrolyte will begin to change directly from liquid to steam. After all, the worst case scenario for this kind of problem is that the battery case is broken, so the lithium ion that is "moving" finally has the opportunity to "come into contact" with oxygen. The consequences can certainly be imagined.

2, overcharge

The principle of over-charge explosion is similar to short circuit, but the culprit is not the electrolyte or electrolyte, but the negative electrode. In the case where the battery is really overcharged, the lithium Atom with a relatively stable negative electrode will be transformed into a needle-shaped lithium metal crystal, piercing the diaphragm between the electrolyte(liquid) and the electrode, and the charge will be connected to the positive electrode, resulting in an internal short circuit., For the rest of the process, please refer to the first point.

3, battery shell damage

Not to mention, instead of relying on electrolytes(liquids) or overcharging with less than stimulating techniques, a knife is cut directly into the battery shell and a fish is broken. Therefore, oxygen successfully enters the battery. Before you could do the disassembly test, the battery was on fire or exploded.

Even so, lithium batteries are still safe

I heard that you are terrified. Is this lithium battery different from the big thunder and the second kick? The author wants to tell you that there is a difference. Let's talk about short circuit first. We have three insurances for this: use good quality charging wire to prevent external short circuit, internal protection mechanism of the mobile phone to prevent short circuit charging, and the inside of the battery can be closed to prevent lithium ions from continuing to move when overheating. With these three steps, the short-circuit directly causes the fire to explode, which is already a very small probability event. For overcharge, the current mainstream brand mobile phones have overcharge protection circuits that will not allow fully charged batteries to be continuously charged. Therefore, scientists have long thought of these dangers, and adopted a corresponding mechanism, so lithium batteries dare to enter our mobile phones, and these foreign amateurs do not have to worry.

The other thing, though, is to speak up for manufacturers, but we have to think about this: Apple, Samsung, and other products that ship millions or even tens of millions of dollars a year as mobile phones, and even small probability events will be magnified. So we get the illusion that the iPhone is poor, and when it comes back to the real danger, these brands aren't higher than other brands, let alone compare them to unreliable knockoffs. Don't most of our concerns about cell phone battery safety arise from these rare cases?

It's time to retire.

The way the battery explodes is believed to be well known. So if you want to avoid a battery explosion, what do you do? First of all, please throw away your universal charge! Charging the battery with universal charge is equivalent to directly giving up the battery protection measures on the mobile phone. Not only is the stability of the current not guaranteed, but it will not be turned off after filling, and it is easy to cause overcharging. As long as you use a non-counterfeit phone to charge the battery, overcharging this situation will not happen.

On the other hand, if your battery "drum pack", the first time to change the battery, do not reluctantly use, because such a battery has been short-circuited inside the situation, continue to use may allow the shell to burst, easily causing fire explosion. Finally, we must use genuine batteries, and we must not be greedy to buy local stalls. The original batteries are expensive. This is the most basic point to ensure safety.

Only to do the above points, your normal charging operation will not pose a fire explosion threat, do not say charge overnight, charge a year is nothing. Throw away your universal charge and your shoddy batteries, which are the ones responsible for the danger and are long overdue.

Let's look back at the death toll of the phone: girls were electrocuted in their sleep by the iPhone 4S and the iPhone screen exploded. According to common sense, the voltage for charging a mobile phone is only 5V, so high-voltage power can not be directly in contact with the human body. If there is high-voltage electricity entering the mobile phone, the most likely situation is that the charger fails, causing leakage of electricity, and at the same time short-circuiting the cell phone battery, causing an explosion, which may be related to the purchase and use of a low-quality charger. Therefore, we do not need to have a psychological shadow because of this incident. As long as we use the original accessories, we do not need to worry. We are afraid that some unscrupulous profiteers will steal chargers and batteries. We must be careful when buying mobile phones.

User issues

@Yuting _ Wu: How dangerous is it to charge and call at the same time?

A: For genuine mobile phones and batteries, it is not dangerous to call while filling. On the one hand, high-voltage electricity will be grounded on the charger and will not enter the phone and battery. On the other hand, there will be a small fever during the call, which is far from threatening the safety of the battery. However, it is recommended that people reduce the number of charging phone calls, because the use of mobile phones when charging will accelerate battery aging.

@ I want to love you better: is it safer to connect to a computer than to charge directly?

A: No, in theory, the safety is basically the same, and because the quality of the charger is uneven, more safety problems will occur on the charger than on the computer. So when buying a charger, don't be cheap.

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