EV battery
Lithium battery '' thermal runaway
by:Vglory
2020-10-31
80% of lithium ion battery accident is due to short circuit, short circuit after the battery fire and explosion accident caused by frequent press power lithium battery safety was again pushed to the forefront of public opinion.
Short circuit is causing more severe consequences associated with 'thermal runaway phenomenon.
Battery material thermal stability is always an important factor and the safety of power lithium battery cathode material compared to the anode material of low energy density and power density with the electrolyte fluid is also considered in the development of thermal runaway.
So looking for good cathode material thermal stability becomes the key to power lithium batteries.
Essentially speaking, 'thermal runaway energy is a positive feedback loop process: rising temperatures will lead to system gets hot, raise the temperature system becomes hot, and this, in turn, let the system become more hot.
Thermal runaway is a very common phenomenon, from the concrete curing to exploding stars, all the possible thermal runaway.
Lithium ion batteries in thermal runaway of the following several reasons: 1, often the overcharge.
2, unauthorized modification of the shell.
3, environmental temperature, more than 60 & deg;
C。
4, isolation of lithium ion battery cathode and anode diaphragm in the tear can lead to short circuit, and short circuit often cause thermal breakdown.
Participate in the 'thermal runaway reaction is lithium cobalt oxide chemical in the battery.
Heating the chemicals reaches a certain temperature, it begins to spontaneous heat, and then developed into the fire and explosion.
In some cases, the organic electrolyte release pressure can lead to cell rupture.
If exposed to high temperature environment, or spark, it is likely to burn.
Thermal runaway of probability related to lithium battery base, China, South Korea and Japan lithium battery production is increased year by year, especially in the field of widely used mobile phone/laptop, battery accident seems to be a bit more.
Between 2006 and 2011, many big electronics companies have happened related event, since entering the 2012 years later, happened in small electronic products is less, but in large applications, such as airplane accidents are common, which explains the following phenomena.
Thermal runaway phenomenon and its strength and the size of the lithium battery, configuration and the number of cells.
Only a few small lithium battery lithium battery unit, so there is something wrong with the thermal runaway from the cells of the opportunity to spread to other unit is relatively low.
And Boeing 787 huge battery is another matter: they are placed in a sealed metal box, not emissions of waste heat, when a unit is hot enough to ignite battery electrolyte, the rest of the cells will quickly follow.
Batteries, lithium metal surface deposition is very easy to form branches lithium dendrite, which pierced the diaphragm, causing direct short circuit is negative.
Moreover, metallic lithium is very lively, can be directly and electrolyte exothermic reaction, its melting point and low, even if the surface of metal lithium dendrite not pierced diaphragm, as long as the temperature a little higher, the lithium metal dissolve, causing short circuit.
The higher the temperature of the material in REDOX dicating, showed that its oxidation ability is weak, the anode material of oxidation ability stronger, react more intense, is the easier to cause safety accidents.
Regardless of the size of the lithium-ion battery pack need maintenance on a regular basis in order to prolong the life, all of the lithium ion battery are usually should be replaced every every 36 months or so.
And, whenever power down to 20% of the time, you should be to charge it, can be damaged by excessive discharge of lithium batteries, thus increasing the possibility of 'thermal runaway' and other accidents.
Lithium-ion batteries, electric vehicles, lithium battery manufacturer, storage battery manufacturer scooter battery manufacturers, product by the supervision and inspection institute of guangdong province, through international CE certification, by the ping an insurance company of China national group, two years warranty, the first in the New Year.
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