today, batteries have become necessities of life, but do you know?
The battery is a very dangerous item. In recent years, the explosion caused by lithium batteries has been frequent. Living in the modern, whenever the eyesight, can always see something hidden battery: the head of the mobile phone, constantly tapping the laptop, the roadside parking car ... are secretly powered by Lithium-ion Batteries.
The problem of the safety of lithium-ion batteries in the discussion, has been constantly heard, after all, these batteries are born ' burst ' temper.
Why does lithium battery become a ' time bomb '?
Commercial Lithium-ion batteries are mainly composed of four parts, namely, positive, negative, diaphragm and Electrolyte. When charging, the lithium ions come out of the cathode, through the electrolyte, through the diaphragm to reach the cathode, the opposite of Discharge. so, with the use of batteries, lithium ions like a bus, carrying a charge as a passenger, constantly in between the two-way, to complete the function of charge and Discharge.
And the role of the diaphragm is to block the positive and negative, to prevent the occurrence of short.
This four-in-one design, to the lithium-ion battery has brought great success, but also in a number of ways to bury the hidden Trouble. first, the electrolyte inside the battery contains a large amount of organic matter, such as vinyl carbonate, diethyl carbonate, dimethyl Carbonate.
Each of these guys comes with a fire-blast attribute, and the face says ' keep away from ignition ' four characters. In addition, once the positive and negative pole of a battery is shorted, it will generate a lot of heat and even Spark.
Many people may have done such an experiment as a child: take the wire to a battery of the positive and negative poles together, The wire will become hot, even can be used to cut foam, is such a principle.
Since the short circuit is so dangerous, people naturally think of using something to separate the positive and negative poles, so the introduction of the DIAPHRAGM. however, modern batteries in pursuit of small volume, in order to ensure energy supply, both positive and negative polarity and electrolyte can not be less, then only to press the ' less important ' diaphragm volume. As a result, the battery diaphragm was ' cut ' to thinner, and the mainstream lithium-ion battery diaphragm was only about 20 microns Thick.
That is to say, the thickness of the two diaphragm folds, just close to the diameter of a hair. Once the film is broken, the problem will be serious. 2016, Samsung Note 7 Battery fire is because the diaphragm is too thin, easy to be some welding burr bad, causing the battery short-circuit caused by explosion.
It sounds as if these batteries were ' injured '.
Even without the ' work injury ' caused by these weld hairs, the battery itself is hidden from the pitfalls of piercing the diaphragm, a phenomenon called ' dendrite '. The problem with Dendrite is a disease written in the lithium battery ' gene '. Because of the dynamics and other factors, lithium batteries in the process of use, the surface of the electrode will form some ' tiny thorn ', These little thorn is called ' dendrite '.
And the longer the dendrite, the larger it will eventually penetrate the diaphragm, resulting in a short circuit.
This tiny little guy with only a few microns has once brought down a big company in the field of Batteries. In the late 1970, a battery that uses lithium metal as an electrode can store more power than other batteries under the same weight, and is therefore favored. The cell phone was using the Battery. This technology is owned by a Canadian company called Moli Energy. however, less than six months after the advent of this battery, due to dendrite problems occurred in a number of explosion accidents, was recalled Worldwide.
Flourished's Moli company, Since then, was eventually taken over by a Japanese company and left the site Hastily.
