Why is it easy to cause explosion and fire of lithium batteries when charging?

Compared with lead-acid batteries, lithium batteries are more prone to explosion and fire 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 in lithium batteries is organic matter, we can straightly understand it as gasoline, which is flammable. So, why can lead-acid batteries use aqueous solutions, but lithium batteries use relatively dangerous organic matter as the electrolyte? Simply put, it is because the maximum ionization voltage of the two is different. The highest ionization voltage of aqueous solution is 2V, and this ionization voltage is far from enough for lithium batteries. In order to increase the energy density, lithium 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. The destruction of the SEI membrane (ie, the solid electrolyte membrane) of the negative electrode is one of the most important reasons. Like lead-acid batteries, lithium batteries are also divided into positive and negative electrodes. The positive electrode is generally lithium 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 compounds appearing during charging cannot be properly placed, and huge heat will appear inside the battery. When the temperature rises, the positive electrode of the lithium battery will automatically release oxygen. When the temperature rises, the presence of combustibles, and the presence of oxygen are all available, the probability of explosion and fire will rise sharply. Because the positive electrode of a lithium battery automatically releases oxygen when the temperature rises, we cannot extinguish the fire by isolating oxygen, which means that dry powder fire extinguishers are useless. Therefore, it is very dangerous for lithium batteries to catch fire. So, how do we deal with the safety of lithium batteries? This is a systematic project, starting from the design of the battery, to the protection board of the battery, and then to charging. Therefore, users who have purchased a lithium battery car must use the battery in accordance with the regulations, be aware of some charging items that are prohibited in the manual, and recommend that everyone conduct a safety inspection of the battery once a year or so to prevent problems. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete.