Cause of the working principle of lithium ion battery and the cause of attenuation

ଲେଖକ: ଆଇଫ୍ଲୋପାୱାର - Leverancier van draagbare energiecentrales

Lithium-ion battery is the fastest secondary battery after cadmium and hydrogen-nickel battery. Users used should all know that the lithium battery will reduce the capacity after using a period of time. This article summarizes and analyzes the possible reasons for the working principle of lithium ion batteries, and the capacity attenuation, I hope to help you.

Lithium ion battery work principle Lithium ion battery is a secondary battery (rechargeable battery), which mainly relies on lithium ions to move between positive and negative electrodes. During the charge and discharge process, Li + is inserted and deserted between the two electrodes: When charging, Li + is escaled from the positive electrode, and the electrolyte is embedded in the negative electrode, the negative pole is in a lithium state; the discharge is reverse. Lithium battery discharge is based on chemical oxidation reactions.

When discharge is discharged, it is when we use the battery to consume power, its positive electrode will embed lithium ions, negative electrode lithium ions. When charging is, the opposite is. He has a certain voltage to form a certain amount of voltage so that the battery generates electricity.

During each charge and discharge cycle, lithium ion (Li) acts as a handling carrier of the electric energy, the movement from the positive electrode → negative electrode → the positive electrode from the positive and negative electrode materials, and converts chemical and electrical energy to each other. Implementing the transfer of charge, this is the basic principle of "lithium ion battery". Due to the electrolyte, the isolation film, etc.

is an electron insulator, so this circulation is not moved back and forth between the positive and negative poles, and they only participate in the chemical reaction of the electrode. Causes of lithium battery capacity attenuation is the fastest secondary battery after cadmium battery and hydrogen nickel batteries. The application of lithium-ion batteries is largely dependent on its stability of the charge and discharge cycle, and other secondary batteries , Lithium-ion batteries are inevitable during cycle.

1 Composition of components. 组分的转变容易引起相转移和物理相结构的变化。 The electrode material phase transition can cause changes in the lattice parameters and lattice mismatch, thereby generating induced stress causes the crushing of the grain, and causes crack propagation, resulting in mechanical damage to the structure of the material, thereby causing electrochemical performance attenuation.

2. The negative electrode material commonly used in the negative electrode material structure is carbon material, lithium titanate, etc., this paper analyzes the typical negative graphite.

锂电池容量衰减首次发生，此阶段负极表面形成SEI膜，消耗部分锂离子。 随着锂电池的使用，石墨结构的改变也会造成电池容量的下降。 Although the morphology of graphite is maintained, the half of its (002) crystal surface is large, resulting in a small grain size in the C-axis direction, and the change in the crystal structure causes cracks in the carbon material, which in turn disrupts the surface of the negative surface.

The film and promotes the repair of the SEI film, the excessive growth of the SEI film consumes active lithium, thus causing the non-reversible capacity attenuation of lithium batteries. 3. 电解液主要包括溶剂、电解质和添加剂三部分。

The decomposition of the solvent, the decomposition of electrolytes can cause lithium battery capacity loss. 电解液的分解及副反应是锂电池容量衰减的主要因素。 无论采用何种正负极材料，在何种工艺下，随着锂电池循环，电解液的分解以及正负极材料界面处的反应都会造成容量衰减。

4, the positive precision reaction is too low when the positive electrode active relative to the negative electrode active is too low, it is easy to charge. The lithium battery positive transition caused capacity loss mainly due to the generation of electrochemical inert substances (such as CO3O4, MN2O3, etc.), destroying the capacity balance between electrodes, and its capacity loss is irreversible.

5, electrode instability in the positive electrode active material instability during charging, reacting with electrolyte reactions. It affects the unstable factors of the positive electrode material, the structural defect of the positive electrode material, the carbon black content, too high of the charging potential, where the positive electrode material structure defect is the weight in the factors. As the available area of ​​the lithium battery is reduced, the filling energy is lowered, and the charging time is gradually shortened.

In most cases, the capacity of lithium battery is linearly decay due to cycle cycle and aging. 6. The storage temperature charge and discharge cycle is not the only reason for lithium battery capacity attenuation, and the lithium battery in high temperature can also cause capacity attenuation.

A full-charged lithium battery will cause 35% capacity loss in the case of 40 ° C (104 ° F) for one year without being used. Super fast charge is also harmful to the battery, which will reduce battery life, which is very obvious for monomer lithium batteries. Lithium battery pack is higher than energy, but it is particularly subtle due to differences in cell batteries.

Lithium battery needs often calculates its capacity attenuation and final life. Capacity attenuation to 80% requires replacement of battery packs, and the ultimate life limit of lithium battery pack should change according to the application of the application, and the user's preferences and the company's guarantee.