Why are lithium batteries so dangerous?

The previous lead-acid battery rarely heard of an explosion, and many people will basically not have a big accident even if overcharged. However, once the lithium battery has an accident, it is the level of explosion and even fire. So why is that?

● Short circuit, overcharge, and overdischarge may cause fire

Shi Xunxian, director of the Industrial Safety Research Institute of the China Academy of Work Safety Science, explained that the lithium batteries commonly used on the market have the advantages of high energy density and long life, but at the same time, there are also risks of accidents such as thermal runaway. When the lithium battery encounters physical damage, internal short circuit, overcharge, overdischarge, poor environment and other conditions, it may catch fire.

● Some processes are not up to standard and some disassemble large battery packs

"It does not rule out that some manufacturers' production process is not up to standard, leading to quality problems such as unclean lithium battery composition and unreasonable ratio, and some manufacturers in order to reduce costs, directly disassemble the large battery packs of second-hand electric vehicles and use them for electric bicycles, which has great safety risks." Added an industry expert who studies lithium batteries.

What are the signs to replace the battery?

● Four abnormal situations must be vigilant

"The reasonable service life of lithium batteries is usually related to the number of cycles and conditions of use, the service life is usually 3 to 5 years, different properties of lithium batteries vary, but the specific life is also affected by a variety of factors such as use habits." Shi Xunxian said that once the battery is found to have "significantly reduced capacity, significantly extended charging time, battery appearance damage or bulge" and other abnormal circumstances, should consider replacing the battery as soon as possible.

Which habits pose risks?

"When I got home from work, I charged the battery first, but before I went to bed, I found that the display light on the charger was still red, so I left it until the next morning." Mr. Hu, a citizen, mentioned his "standard" charging process, unaware of anything wrong. He told reporters that this should be a common practice for the vast majority of e-bike users.

Recently, Mr. Hu also started charging his car in the shed downstairs. In the evening of April 10, it was raining lightly, because he was worried about rain damage to the charger, he found an old charger that had been used before, tried it, and the interface was also suitable, so "make the best use of it".

● Improper habits: overcharging, using unsuitable chargers

In the eyes of the industry, it is precisely this "common" and saving practice that brings great risks not only to the users themselves, but also to the neighbors. Director Shi Xunxian gave a detailed introduction to reporters about the situation of battery fire caused by improper use habits.

"The most common are overcharging, the use of inappropriate chargers, external damage to the battery, and circuit system failures." He introduced that overcharging of the battery will increase the internal temperature and pressure of the battery, accelerate the aging of the battery, and even lead to battery deformation and leakage, which will obviously increase the risk of fire and explosion of the battery.

The above lithium battery research experts also added to this: the charger has a "limiting constraint" effect on voltage and current, if the charger this protection mechanism fails, it will lead to overcharging of the lithium battery, and then cause the battery temperature to be too high, which lays a hidden danger for the fire.

Therefore, choose the original or meet the specifications of the charger, choose a regular manufacturer of lithium batteries. Because regular lithium battery manufacturers have a thermal management system designed by professional technicians, it will prevent the lithium battery from getting out of control. The small workshop three no products are often simple assembly, encounter risks without security.