For a full battery, the forming factor of the first efficiency is also related to the side reaction of the first charge and discharge and the difference in the voltage range of the first charge and discharge.

    The first is the influence of the specific surface area of ​​the graphite negative electrode. When the specific surface area of ​​the graphite negative electrode is larger, the area of ​​the SEI film will be larger, which will consume more lithium ions and reduce the first-time efficiency of the full battery.

    Another factor influencing efficiency for the first time is the formation charging system. When the SEI film formed by chemical conversion is thinner and denser, the consumption of lithium ions in this process can be reduced, and the first-time efficiency can be improved. In order to ensure the formation effect of the SEI film, the chemical charging capacity is an important consideration.

    In addition, too large an excess of the negative electrode requires the formation of more SEI film, so it will also reduce the first-time efficiency to a certain extent. The addition of PC solvent to the electrolyte will widen the operating temperature window of the lithium-ion battery, but if there is no corresponding film-forming additive pair to protect the negative electrode, it will easily cause the PC to peel off the graphite negative electrode and reduce the first time of the full battery. efficiency.

    To sum it up, first of all, the editor introduces the calculation method of the first efficiency of the full battery, which is the divided discharge capacity/(formation charge capacity divided charge first step charge capacity). In addition, we know the determinants of the first effect of the full battery: the first effect of the full battery is equal to the lower of the first effect of the positive and negative poles. Finally, several influencing factors of the first effect of a full battery are introduced. In order to increase the product capacity, we must hope that the higher the first efficiency of the full battery, the better, so can the first efficiency of the full battery be significantly improved by relying on the several first efficiency factors mentioned above? The answer is no. The above several improvement measures either have little effect or cause other negative effects. In short, they are not effective ways to improve the efficiency of the first time.