Objective analysis for lithium-ion battery pure electric vehicles, from the cell level, charging is still a big problem, the multiplier performance of lithium-ion batteries on the one hand by the cathode / electrolyte / cathode electrode material with the intrinsic transmission characteristics of the system constraints. Therefore, "fast charging" has also become a gimmick for many manufacturers.
On the other hand, the electrode process and cell structure design also have a significant impact on the multiplier performance. Based on the embedded reaction mechanism, lithium-ion batteries are not suitable for "fast charging" in terms of the most intrinsic carrier conduction and transport behavior.
After all, the diffusion coefficients of Li-ion batteries in cathode materials and anode graphite anode materials are generally lower than the rates of heterogeneous redox reactions in other batteries, making the intrinsic carrier conduction and transport behavior of Li-ion battery systems dependent on the conductivity of cathode and anode materials and the diffusion coefficients of Li-ion batteries and the conductivity of organic electrolytes, which are the main factors.
The negative electrode of lithium-ion battery has a SEI film on its surface. Since the polarization of powder electrode in organic electrolyte is much more serious compared to the aqueous system, in fact, the multiplier performance of lithium-ion battery is largely controlled by the diffusion of lithium-ion battery in the SEI film. Under large multiplier charging conditions, the lattice of positive material is damaged, and the negative graphite flake layer is similarly damaged, and it can be said that under high multiplier or low temperature conditions These factors will accelerate the decay of capacity and make the cathode surface easy to precipitate lithium and bring serious safety hazards, thus seriously affecting the service life of power batteries.
Therefore, research results have confirmed that the nature of the embedded reaction determines that lithium-ion batteries are not suitable for high rate charging.
The cycle life of a single battery in fast charge and fast discharge mode will continue to decline, and the battery performance decays significantly in the later stages of use.
