Cause analysis of thermal runaway of lithium battery

In essence, the thermal runaway of lithium batteries is a positive energy feedback cycle: increased temperature will cause the system to heat up, and the system will heat up and increase the temperature, which in turn makes the system hotter. Thermal runaway is a very common phenomenon. From concrete curing to star explosions, thermal runaway may occur. 1. Overcharge often. 2. Unauthorized modification of the shell. 3. The ambient temperature exceeds 60C. 4. The tearing of the separator separating the negative electrode and the positive electrode of the lithium battery will cause a short circuit, and the short circuit will often cause thermal collapse. The thermal runaway of lithium batteries is important because the internal heat generation is much higher than the heat dissipation rate, and a large amount of heat is accumulated inside the lithium battery, which causes a chain reaction and causes the battery to catch fire and explode. Participating in the thermal runaway reaction is the cobalt oxide chemical in lithium batteries. When this chemical is heated to a certain temperature, it starts to heat up by itself, and then develops into fire and explosion. In some cases, the release of pressure from this organic electrolyte can cause the battery to rupture. If exposed to a high temperature environment, or encounter sparks, it may also burn. The phenomenon of thermal runaway and its intensity are related to the size, configuration and number of battery cells of the lithium battery. Small lithium battery packs have only a few lithium battery cells, so the chance of thermal runaway spreading from the problematic battery cell to other cells is relatively low. The huge battery packs of the Boeing 787 are another matter: they are housed in a sealed metal box and cannot emit waste heat. When a battery cell is hot enough to ignite the electrolyte, the remaining battery cells will quickly follow up. 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: What are the advantages and disadvantages of iron-lithium battery electric vehicles?