Objective analysisLithium Ion BatteryPure electric vehicles, from the level of batteries, the difficulty of charging is still a big problem.Lithium Ion BatteryThe rate performance is affected by the positive electrode on the one hand/Electrolyte/The negative electrode material is matched with the intrinsic transmission characteristics of the system, so "fast charging" has also become a gimmick for many manufacturers. On the other hand, the pole piece process and cell structure design also have a greater impact on the rate performance. Based on embedded reaction mechanism,Lithium Ion BatteryIn terms of the most intrinsic carrier conduction and transport,Lithium Ion BatteryNot suitable"Fast charge".
After all, lithium-ion batteryThe diffusion coefficient in cathode materials and graphite graphite anode materials is generallyotherLow rate of heterogeneous redox reactions in batteries, Making lithium ion batteriesThe intrinsic carrier conduction and transport of the system depends on the conductance andLithium Ion BatteryThe main factors are the diffusion coefficient and the conductivity of the organic electrolyte.
There is a layer on the negative electrode surface of the lithium ion batterySEIMembrane, because the polarization of the powder electrode in the organic electrolyte is much more serious than the water system,ActuallyLithium Ion BatteryThe rate performance is greatly affected byLithium Ion BatteryinSEIThe control of diffusion in the film, under the condition of large rate charging, the lattice of the positive electrode material is destroyed, and the negative electrode graphite sheet layer is the samemeetinggot damage,It can be saidAt high magnification or low temperature,These factors will accelerate the decay of capacity,MakeThe surface of the negative electrode is prone to lithium deposition and brings serious safety hazards, which seriously affects the service life of the power battery. Therefore, the research results have confirmed that the essential characteristics of the embedded response determineLithium Ion BatteryNot suitable for high rate charging. The cycle life of the single battery in the fast charge and fast discharge mode will bekeep falling, And the performance of the battery deteriorates significantly in the later period of use.
