Share a few improve the security of the lithium ion battery

Source: 2020 - 04 - 15 it hits: time to improve the security of the lithium ion battery based on the above analysis of the lithium ion battery safety, can from the following three aspects: to improve the safety of the lithium ion battery: one is to improve the thermal stability of the electrode material, actively improve the performance of the battery; Second, improve the lithium ion battery electrolyte, electrolyte using security; Third, through external means, optimize the design of the lithium ion battery and management, real-time monitoring of lithium ion battery charge and discharge process, deal with abnormal problem in time, ensure the safety of the lithium ion battery. 1. Improve the thermal stability of the electrode material in general, thermal stability of battery material is the root cause of the lithium ion power battery safety. Therefore, in order to fundamentally improve the safety of the lithium ion battery, it is necessary to start from thermal stability of the battery material itself. ( 1) Research has shown that positive electrode material is caused by the reaction between anode materials and electrolyte battery is one of the main reasons for high temperature safety problems. Therefore, looking for the anode material with good thermal stability is an effective means to improve the safety of lithium-ion batteries. At present, lithium transition metal oxide is a major anode materials of lithium ion batteries. At present, the layered lithium cobalt oxide ( Li C o O2) Lithium, nickel acid ( LiNi O2) , manganese acid lithium ( LiMn2O4) And polyanion lithium iron phosphate ( 人生如果e P O4) The most widely is the study of cathode materials. Among them, LiCoO2 moderate thermal stability, electrochemical performance is excellent, but the price of cobalt of the storage capacity is small, high and great toxicity limits its application. Although LiNiO2 capacity is high, but the preparation of demand is high, especially the thermal stability is poor, not suitable for as the anode material; Spinel LiMn2O4 has the raw material of low cost, simple synthesis process, high thermal stability, good resistance to overcharge, the advantage of high discharge voltage platform materials; LiFePO4 is cheap, stable, environmental protection, heat resistance. McNeil [ 5] Different cathode materials research under the charging status of the thermal stability, the results show that the thermal stability of the lithium iron phosphate is one of the best, and other materials, the thermal stability of LiNi3 o1/8 c / 4 mn3 / O2 & gt; Li1 - xMn2 - xO4 > LiCoO2 > LiNi0。 7 Co0。 2 Ti0. 05年Mg0。 05 O2 > LiNi0。 8 Co0。 2 O2 > LiNiO2。 Yang and others have come to the same conclusion, namely LiFePO4 is higher than the thermal stability of LiCoO2, LiNiO2 and LiM n2O4, under the charging status, when the electrolyte is below 340 ℃, LiFePO4 is not showed obvious endothermic or exothermic phenomenon. Although find a cathode material with good thermal stability is very important, but for the anode materials were modified to improve its thermal stability is not allow to ignore. Research method is optimum synthesis condition, improvement of synthetic method, improvement of electrode materials, etc. Modification of electrode material is the measures to improve the thermal stability of lithium-ion batteries. Commonly used methods of modification surface coating modification and doping modification. The surface coating can reduce the reaction between active material and electrolyte, reducing the anode material in the process of overcharge release oxygen, stable base material [ 7] Phase change, so as to improve the thermal stability of lithium-ion batteries. At present, the type of cladding material is more, such as: 3 oxidation 2 aluminium oxide coating ( Alumina) , titanium dioxide ( Titanium dioxide) , phosphoric acid, MPO4) Coating ( Aluminum (M = Al) , iron ( Fe) The cobalt ( C o) , aluminum hydroxide ( Al ( 哦) 3) Coatings, carbon coated with organic coating, though not in theory to determine what types of cover material is most suitable for the surface modification, but to a certain extent, improve the thermal stability of the positive electrode material. Ch o et al. [ 8] Found in LixCoO2 coated on the surface of nano aluminum phosphate ( AlPO4) Particles can effectively restrain exothermic reaction between anode materials and electrolyte.