What are the ways to guard against short circuits in lithium battery packs

Due to the influence of many factors such as material system and manufacturing process, lithium batteries have the risk of internal short circuit. Although lithium batteries have undergone strict aging and self-discharge screening before leaving the factory, due to process failure and other unpredictable use factors, there is still a certain failure probability that causes internal short-circuits during use. Regarding power lithium-ion batteries, there are hundreds or even tens of thousands of lithium batteries in their battery packs, which greatly magnifies the probability of internal shortfalls in the battery pack. Because the energy contained in the power lithium-ion battery pack is extremely large, the occurrence of an internal short circuit can easily induce malignant accidents, leading to casualties and property losses. TE's PPTC and MHP-TA series products provide a possible solution to prevent the occurrence of vicious accidents once the power lithium-ion battery has an internal short circuit. Regarding parallel-connected lithium-ion power lithium-ion battery modules, when one or several batteries have an internal short-circuit, the other batteries in the battery module will discharge it, and the energy of the battery pack will cause the temperature of the internal short battery to rise rapidly , It is easy to induce thermal runaway, and eventually cause the battery to catch fire and explode. As shown in Figure 1. Conventional temperature detection can tell the IC to cut off the main circuit when the battery is heating up, but it cannot prevent the continuous discharge inside the parallel battery module. Because the main circuit is cut off, all the energy of the battery module is concentrated in the internal short-circuit battery, which is new. Increase the chance of thermal runaway. The ideal method is to cut off the connection circuit between the battery and other batteries in the module when it is found that a certain battery is short and heats up. As shown in Figure 2, assembling TEPPTC or MHP-TA series products on a single battery, when an internal short circuit occurs, TE protection devices can effectively block the connection between the internal short circuit battery and other batteries in the module, and beware of the occurrence of vicious accidents. . Regarding the power lithium-ion battery pack with a large number of single cells, the battery and device internal resistance consistency requirements are high when the battery is assembled, and the MHP-TA has a very good consistency of device resistance due to its internal bimetal structure, which can greatly Meet the requirements on the internal resistance of the battery. Li-ion power lithium-ion battery short circuit is extremely harmful, so it is essential to do a good job of short-circuit protection of the battery pack. The above two treatment methods can effectively protect the circuit when the battery is short-circuited. 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: Analysis of the top ten advantages of lithium batteries for electric vehicles