Why is lithium ion battery easy to catch fire when charging?

Compared with lead-acid batteries, lithium-ion batteries are more prone to safety accidents, mainly because the electrolytes of the two are different. The electrolyte of lead-acid batteries is generally an aqueous solution, which is not easy to catch fire; while the electrolyte of lithium-ion batteries is organic matter, which is flammable. So, why can lead-acid batteries use aqueous solutions, but lithium-ion batteries use relatively dangerous organic matter as the electrolyte? Simply put, the highest ionization voltages of the two are different. The highest ionization voltage of aqueous solution is 2V, and this ionization voltage is far from enough for lithium-ion batteries. In order to increase the electrical energy density, lithium-ion batteries must use organic matter as the electrolyte. When the organic electrolyte is sealed in a narrow space like the battery, there will be a higher risk of explosion and fire. Why do lithium-ion batteries easily catch fire when charging? The destruction of the SEI membrane (ie, the solid electrolyte membrane) of the negative electrode of a lithium ion battery is one of the most important reasons. Like lead-acid batteries, lithium-ion batteries are also divided into positive and negative electrodes. The positive electrode is generally lithium ion transition metal oxide, and the negative electrode is graphite and carbon. When the SEI film on the surface of the negative electrode is destroyed, the carbon and lithium ion compound that appears during charging cannot be properly placed, and huge heat will appear inside the battery. When the temperature rises, the positive electrode of the lithium-ion battery will automatically release oxygen. When the three combustion conditions of temperature rise, the presence of combustibles, and the presence of oxygen are met, the probability of explosion and fire will rise sharply. It is precisely because the positive electrode of a lithium-ion battery automatically releases oxygen when the temperature rises, so we cannot extinguish the fire by isolating oxygen, that is to say, dry powder fire extinguishers are useless. Therefore, it is very dangerous for lithium-ion batteries to catch fire. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Lithium-ion battery export materials and precautions during transportation