What are the important reasons for thermal runaway of lithium-ion batteries?

In essence, the thermal runaway of lithium-ion batteries is a positive energy feedback cycle process: 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 appear. 1. Overcharge often. 2. Unauthorized modification of the shell. 3. The temperature of the situation is 60C higher. 4. The tearing of the barrier between the negative electrode and the positive electrode of the lithium ion battery will cause a short circuit, and the short circuit will often cause thermal collapse. The main reason for the thermal runaway of lithium-ion batteries is that the internal heat generation is much higher than the heat dissipation rate, and a large amount of heat is accumulated inside the lithium-ion battery, which causes a chain reaction, which causes the battery to catch fire and explode. Participating in the thermal runaway response is the cobalt oxide chemical in lithium-ion batteries. When this chemical is heated to a certain temperature, it will start to fever spontaneously, and then grow into fire and explosion. Under certain circumstances, the release of pressure from this organic electrolyte can cause the battery to rupture. If it is exposed to high temperatures, it may be touching a spark, and it may also burn. The phenomenon of thermal runaway and its intensity are related to the size, setting, and number of battery units of the lithium-ion battery. Small lithium-ion battery packs have only a few lithium-ion battery units, so the time for thermal runaway to flow from the problematic battery unit to other units 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 unit is hot enough to ignite the electrolyte, the remaining battery units will quickly follow up. There are many factors that cause a fever out of control of lithium-ion batteries. Generally speaking, they are divided into two categories, internal factors and external factors. The important internal factors are: defects in the battery lead to an internal short circuit; improper use of the battery causes the internal lithium dendrites to stimulate the short circuit of the positive and negative electrodes. 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. Previous article: What are the important assembly methods for soft-pack lithium-ion batteries?