New method to prevent short circuit of lithium ion battery pack

Posted by sere on February 17th, 2020

Lithium lion battery pack has the risk of internal short circuit due to the influence of material system and manufacturing technology. Although lithium ion batteries have undergone strict aging and self-discharge screening when they leave the factory, due to process failure and other unpredictable use factors, there is still a certain failure probability that leads to internal short circuit in the use process. For power batteries, there are hundreds or even tens of thousands of lithium-ion batteries in the battery pack, which greatly magnifies the probability of the occurrence of internal shortness of the battery pack. Due to the great energy contained in the power battery, the occurrence of internal short circuit can easily induce malignant accidents, resulting in casualties and property losses.

For parallel lithium-ion power battery modules, when one or several batteries are within a short time, other batteries in the battery module will discharge to them. The energy of the battery will cause the temperature of the inner short battery to rise rapidly, which will easily induce thermal runaway, and eventually lead to the battery fire and explosion.

Conventional temperature detection can tell IC to cut off the main circuit when the battery heats up, but it cannot prevent the continuous discharge inside the parallel battery module, and because the main circuit is cut off, all the energy of the battery module is concentrated in the internal short-circuit battery, which increases the probability of thermal runaway. Ideally, when a battery is found to be heating up due to internal shortness, the circuit connecting that battery to the other batteries in the module can be cut off.

The short circuit of lithium ion battery pack is very harmful, so it is necessary to protect the short circuit of battery pack. The above two solutions can effectively protect the circuit when the short circuit happens to the battery.