172 views Yuda Electronic (HK) Technology Co.,Limited. 2018-05-29
Why cell phone battery will explode?
Most of the mobile phone batteries we use today are lithium ion batteries. There are two common causes of explosion of lithium-ion batteries: overheating and mechanical damage.
Overheating is the most common cause of explosions in lithium-ion batteries. This usually refers to the external factors caused by thermal runaway, which is the temperature of a part of the battery rise, and then lead to other parts of the temperature rise, so that more and more battery heat, forming a vicious cycle, the battery electrolyte began to expand, steam appears, Eventually the battery exploded due to excessive internal pressure.
Mechanical damage is another reason, in short, extrusion causes a short circuit. Lithium-ion batteries are lightweight and durable, and battery improvements play an important role. However, it is precisely because we are increasingly dedicated to the pursuit of lighter, lithium-ion battery in the design, the diaphragm between the housing and the positive and negative levels become thinner, which lays hidden dangers for battery safety. Because once the diaphragm is damaged, it may cause a short circuit, resulting in heat generation inside the battery.
So what is the reason for the Note 7 explosion? Some media speculated that the explosion of the Note 7 was caused by a mechanical damage. Because in a number of explosions, the parties did not charge the mobile phone and did not mention that the mobile phone was expansion before the explosion. From the post-explosion pictures, if the explosion is caused by overheating, the area burned by the mobile phone should be larger.
It should be noted that, regardless of the cause of the out of control, different battery cells have different forms of performance, and some may catch fire, but they do not necessarily explode.
In industry, lithium ion batteries use different safety technologies for different safety issues. For example, thermal fuses and thermistors can be used to prevent overheating caused by short circuits.
The most common solution to prevent battery explosion is to increase the safety valve. When the internal pressure of the battery is too high, gas can escape through the safety valve, thus preventing the explosion.
A similar approach is to make the battery case thin, which may sound a bit unbelievable. The thinner the battery case is, the easier it is to crack? However, in fact, it is precisely because the light and thin battery casing can withstand less pressure, so the thermal runaway can occur in the battery, but the pressure has not reached a particularly dangerous degree when the crack is opened in time, which is equivalent to the formation of a safety valve.
There is also the use of anti-flammable electrolytes. Lithium-ion battery electrolytes generally have the characteristics of low boiling point, low ignition point, once the battery is damaged, the electrolyte exposed to the air, it is likely to bring about the risk of explosion.
What kind of mobile phone battery is safer?
First of all, understand the battery classification. Mobile phone batteries have experienced nichrome batteries and nickel-metal hydride batteries. As mentioned above, lithium-ion batteries have become mainstream mobile phone batteries because of their obvious advantages in performance. But now, lithium-ion batteries have also derived many sub-categories.
According to the electrolytic materials used in lithium ion batteries, lithium ion batteries can be classified into liquid lithium ion batteries and polymer lithium ion batteries. The difference is that liquid lithium-ion batteries use liquid electrolytes, and polymer lithium-ion batteries replace solid polymer electrolytes. In addition, lithium-ion batteries have lower production costs. Compared with common liquid lithium-ion batteries, poly-lithium batteries not only have higher capacity and longer life, but also have higher safety due to the absence of liquid leakage problems.
How can I avoid battery explosion?
However, even a relatively safe lithium-ion battery may still explode due to high temperatures, short circuit, overcharge, or battery damage. In theory, no battery can be absolutely safe, and safety can only be compared to different standards.
What technologies can prevent the battery from exploding?
Therefore, in normal use, we still need to avoid extreme situations. Here are some guidelines for the safe use of lithium-ion batteries:
Use original mobile phone batteries, do not use batteries made by unknown manufacturers
Do not charge in an environment where the temperature is too high or too low (less than zero degrees). Overheating can easily cause the battery to overheat. When the temperature is too low, lithium metal will precipitate on the surface of the negative electrode to form lithium crystals. The deposition of lithium crystals will pierce through the separator. Causes a short circuit in the battery (but now some batteries have been added to prevent the charging technology in a low temperature environment);
First generation iPhone battery pictures
If you need to use some functions that are easy to heat the phone when you charge it, or charge it through the night, then it’s best to remove the phone cover to ensure that the battery is properly cooled;
Maintaining more than half of the battery’s power is helpful for extending battery life because lithium ion batteries are vulnerable to damage at low voltages;
Pay attention to the charging environment, try not to charge near flammable materials, in the car or in the safe passage;
Finally, don’t die out! You may often see online video-shake-out on the Internet: using a knife, smashing with a hammer, baking with a microwave oven, etc… You don’t have to waste time mimicking it. The ending is likely to be only one – explosion.
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