Lithium battery safety issues attract attention

Lithium-ion batteries have the advantages of high energy, long cycle times and high efficiency. They are widely used in various electronic products. For example, our commonly used charging treasure consists of a 18650-cell lithium-ion battery. This battery also constitutes the battery of the notebook.

Of course, lithium-ion batteries have many other applications. For example, smart phones, the vast majority of mobile devices are already using lithium-ion batteries; electric bicycles, the electric vehicle industry is increasingly demanding lithium-ion batteries, in the future energy storage field, lithium-ion batteries will also be released Glorious.

However, while lithium-ion batteries benefit human beings, they also have potential dangers. The frequent burning and explosion of lithium-ion batteries poses a great threat to people's lives and property.

At 5:53 pm on May 31, 2016, a lithium battery fire and explosion accident occurred in Jiangsu Haisida Power Co., Ltd. in Qidong, Nantong, Jiangsu Province. The accident occurred in a three-layer lithium battery at the company’s Nanyuan West Road in Qidong City. Fully placed on the warehouse. After the fire officers and soldiers arrived, they quickly launched a rescue. During the disposal, an explosion suddenly occurred on the scene. The accident caused 12 employees and 8 firefighters to be injured on the spot. Subsequently, the injured were rushed to Nantong and Qidong Hospital for treatment. However, one firefighter and one Haidida employee died after being rescued.

At present, the cause of the accident initially investigated is caused by the internal short circuit of the battery, which causes rapid temperature rise and affects the explosion caused by the change of the adjacent battery.

There is also a fire in the Tesla model charging on January 1, 2016, and many electric vehicles in Beijing, Hefei, etc., are self-igniting, the Shenzhen battery factory has a sudden fire, and the lithium battery trucks in Hunan have been on fire.

Boeing Company of the United States warned passenger airlines that mass shipment of lithium-ion batteries could cause devastating fires. The US Federal Aviation Administration also issued a statement saying that its tests showed a huge risk in transporting lithium batteries.

Overall, according to FAA statistics, 27% of battery accidents occurred between 1991 and 2007 were lithium battery accidents, of which 68% were due to internal or external short circuits and 15% due to charging. Or caused by discharge, 7% due to unexpected start of equipment, 10% for other reasons. Once the lithium battery is burned, the combustion can be extinguished only after it is consumed, and the HALON1301 fire extinguishing agent equipped on the aircraft can not prevent the thermal runaway of the lithium battery, so the safety risk of lithium battery air transportation is even more protruding.

Although the lithium battery is small in size, it has high energy and contains a flammable electrolyte. If this kind of energy is applied, it is efficient energy. If it is not applied well, it will generate a lot of heat to cause combustion and form a disaster. A lithium-cobalt 18650 ion battery with a capacitance of 2-3Ah has an electric energy of 25-40KJ, and the chemical reaction can produce 280 kj of heat after combustion. That is to say, once the lithium-ion battery is out of control, the heat generated is very large, so its harmfulness is also great. You can see what happens when the lithium battery is out of control.

Researchers have shown that due to the internal temperature rise of the lithium battery, the internal thermal runaway reaction occurs, and the gas is generated to cause leakage of the positive electrode of the lithium battery, thereby forming a small orange-red torch-like flame; at the same time, the electrolyte inside the battery begins to eject and occurs. Burning, a strong flame is formed very quickly, and then a large number of white Mars are generated at the positive electrode and a loud sound is emitted, releasing a large amount of gas and burning violently. In a matter of seconds, this phenomenon is accelerated and an explosive reaction occurs, resulting in a loud sound. When the lithium battery is burned, the maximum temperature can reach more than 700 degrees, and the intensity of the combustion reaction can be seen.

Lithium battery safety issues attract attention

So what do we need to pay attention to when using lithium batteries?

Do not overcharge and discharge, overcharge and overdischarge will cause great damage to the lithium battery, it is also likely to cause the internal temperature of the battery to rise, causing combustion. The current lithium-ion battery or charging treasure will automatically stop charging when the battery is fully charged. That is to say, if your lithium battery is full, it will be white charger on the charger. And none of us can guarantee that the characteristics of the battery's charge and discharge protection circuit will never change and the quality will be foolproof, so your battery will be on the edge of danger for a long time. So try not to charge for a long time.

At the same time, it is not advisable to use the power of a photolithium battery. "Try to run out of battery power, it is best to use automatic shutdown." This practice is actually only a nickel battery, the purpose is to avoid memory effects, unfortunately it is also completely unsuitable on lithium batteries. If you insist on using the "first three 12-hour long charge activation" method that is circulated, it will not actually work.

The best way is to use it with your charge and use it with your charge.

Do not let the lithium battery come into contact with high temperatures. The effect of temperature on battery life is actually very large. The higher the temperature, the lower the life of the lithium battery. Experiments have shown that at more than 70 degrees, a spontaneous exothermic reaction occurs inside the battery cell, causing the temperature to rise sharply. At more than 130 degrees, the lithium battery will react with the gas, causing the internal pressure to be too large, and the battery is opened to cause a combustion explosion.

It is hoped that lithium batteries will benefit human beings while reducing the occurrence of safety accidents, and research on advanced technologies will be further developed!

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