How to ensure the safety and life of lithium-ion batteries?

Source: 2020 - 03 - 25 20:52 hits: how to ensure the safety and life of lithium-ion batteries? For lithium ion batteries, may face in the process of application of different test, some application scenarios may even more of a challenge for lithium ion batteries. We hope that the lithium ion battery can be more intelligent, lithium ion battery using policies to stop in time according to the use environment adjustment, on the one hand, to ensure the safety of the lithium ion battery, lithium ion battery, on the other hand also can guarantee function and service life. 1. Smart ego to protect lithium ion battery is the basic function of lithium ion batteries, lithium ion battery pack now BMS system based on can over temperature protection, current protection function, but it is in system level protection, lithium ion battery and intelligent planning may protect themselves at the levels of lithium ion battery, such as adding additional battery electrodes induction, add temperature reaction intelligent materials, by adding some smart structures in the lithium ion battery and materials, and intelligent planning on lithium ion batteries. 1. 1 internal short-circuit prevention programmes internal short circuit is a serious problem affecting the safety of lithium-ion batteries. Lithium-ion battery caused by lithium dendrite, excess material such as short circuit often can cause serious security problems. In order to solve the lithium-ion battery, lithium dendrite growth caused by internal short circuit accident, people developed a variety of methods to monitor the growth of lithium-ion battery lithium dendrite. Wu and others planning function of the diaphragm, for example, the diaphragm in the center of the traditional polymer diaphragm also participated in a metal layer, the layer of metallic lithium dendrite detector function, by monitoring the voltage difference between metal and the cathode, can complete the lithium dendrite monitoring, make the function of the diaphragm is to save the traditional diaphragm, and lithium dendrite monitoring in the end. The characteristics of the diaphragm is the center of the diaphragm layers involved in sio2. When lithium dendrite growth to a certain extent, the diaphragm is breakdown, sio2 can react with metallic lithium, lithium dendrite, thereby preventing the further growth of lithium dendrite. 1. 2 intelligent avoid overheating lithium-ion batteries, lithium-ion battery assumption overheating ( Such as external heating, heat released during the process of short circuit, etc. ) Leads to the diaphragm contraction, which leads to the positive and negative electrode short circuit, leading to thermal runaway. Traditional pp - pe- Pp composite membrane under low temperature, can end locking function, and then prevent the positive and negative electrode reaction, the effect of suppressing batteries overheating, but if high temperature cross, pp layer also shrink, the three layer composite diaphragm will be invalid. In order to solve the problem of safety of lithium ion batteries overheating, Yim, etc. Ordinary flame retardant electrolyte have been known to have a significant impact on the function of the lithium ion battery, so it is difficult to use in the practical application. Yim, such as flame retardants was placed in a separate capsule, the capsule of the outer wall material in the electrolyte is very stable, generally will not affect the function of the lithium ion battery. When the temperature exceeds 70 ℃, flame retardant DMTP under the action of vapor pressure, result in the crack of the shell, will be released into the electrolyte flame retardants, lead to sharp decline in the electrical conductivity of electrolyte, to prevent further reaction of the battery. Above the protection of lithium ion battery method is one-off, that once the protection mechanism is activated, it means the battery failure. In order to solve this problem, Yang and others designed a kind of protection method, using smart electrolyte can prevent temperature under the influence of reversible sol-gel Gel shift, which can activate the protection method again and again. The electrolyte is mainly composed of PNIPAM/AM. When the temperature exceeds the transition temperature, PNIPAM will be changed from hydrophilic to hydrophobic, thereby significantly inhibit the proliferation of the ion. Importantly, the reaction is complete, reversible, when the temperature drops, so repeated protect battery can end. The technology can be applied to river on the super capacitor, protect the safety of the capacitor.