Why did lithium batteries become a bomb?

From a chemical point of view, there are many reasons for the explosion of lithium batteries, and a considerable part of the reasons have a lot to do with the shortcomings of the manufacturer's planning. As we all know, a major cause of battery blasting is battery short circuit (that is, there are no electrical appliances in the circuit where the battery is, so that the current through the battery is too large in a short period of time), and whether it is a battery short circuit or an overcharge (lithium battery blasting) Another important cause of this is that the battery charging voltage is higher than its set upper limit), which will cause a lot of heat and gas to accumulate in the lithium battery in a short period of time (the lithium battery will generate gas during operation). In this way, in order to release the pressure, the lithium battery will either activate the internal pressure release device, or it will crack the shell straight, and both of these situations will cause the internal data of the battery to touch the air straightly and then burn. Generally speaking, blasting and incineration of lithium batteries are rarely caused by external circuit failures, which means that most of the blasting and incineration of lithium batteries are due to the shortcomings of the battery's internal planning. For example, in the aforementioned Sony laptop battery blasting incident, metal impurities were detected in the electrolyte part of the problem battery. This incident was also due to the unexpected conduction of the metal impurities and the formation of an internal short circuit, which induced blasting. of. Coincidentally, the fire on the lithium battery of the Boeing 787 aircraft is also related to the fact that the function of the electrolyte of the aircraft battery is greatly reduced in a special environment, and then an internal short circuit is induced. Of course, in the two lithium battery explosion and incineration incidents, all touched are traditional lithium batteries, and the protagonist in the Samsung Galaxy Note 7 explosion incident is the lithium ion polymer battery, so the lithium ion polymer battery is in this category. What's special in the matter? In fact, generally speaking, because lithium-ion polymer batteries do not have a hard shell, the possibility of violent blasting and incineration has been greatly reduced. Such batteries will explode early due to the poor impact resistance of the shell when a blasting incident occurs. , And then usually manifests as slow incineration after blasting. However, the high degree of variability in the shape of lithium-ion polymer batteries can not only give equipment manufacturers more free planning space, but also often require additional planning for the battery pack. In this way, it is inevitable that the battery pack plan is not good enough, which will cause trouble. In the blasting of the Samsung Galaxy Note7, it has been preliminarily determined that the battery pack with major defects in the processing technology is probably the culprit of the blasting. 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.