Basic knowledge of lithium ion battery anode and cathode materials

Lithium ion battery is a kind of rechargeable battery. It mainly relies on lithium ions moving between the positive and negative poles to work. In the process of charging and discharging, Li + embedded back and forth between the two electrodes: when charge the rechargeable battery, Li + embedded from the anode and embedded in the cathode through electrolyte, so the cathode is in the rich lithium state; while discharge has the opposite condition. Commonly use electrode materials containing lithium as battery electrode, which is the representative of modern high-performance batteries.

Lithium ion batteries (Li - ion, lithium ion battery) : lithium ion battery has a light weight, large capacity, no memory effect, etc., and widely applied, now many of the digital devices are used the lithium ion battery as a power source, although its price is relatively expensive. High energy density lithium ion battery, its capacity is the same weight of 1.5 to 2 times of Ni-Mh batteries, and have very low self-discharge rate. In addition, the lithium ion battery has almost no "memory effect", and does not contain toxic substances etc. also is the main reason that it is widely used.

Working principle of the lithium ion battery:

Lithium ion batteries in the department of lithium battery of lithium ion battery principle structure lithium battery and lithium ion batteries. The current mobile phones and laptops are lithium ion battery, usually people commonly known as it is lithium battery. At present, such as mobile phone use lithium ion battery, and the true lithium-ion batteries because the risk is big, not applied to daily electronic products.

Lithium ion battery anode materials are:

Lithium ion battery cathode materials for carbon materials, lithium ion battery cathode material is a compound of lithium, no metal lithium exists, only lithium ion, this is the lithium ion battery. Lithium ion battery refers to the floorboard of the lithium ion embedded compounds as the anode material battery. Lithium ion battery charge and discharge process is the embedded lithium ion and embedded process. Embedded in lithium ion and embedded process, at the same time with lithium ion equivalent embedded electronic and embedded off (habit to use embedded or embedded said, on the positive and negative) inserted with insert or take off., in the process of charging and discharging lithium ion in the back and forth between positive and negative electrode embedded/embedded and insert/take off the plug, vividly called "rocking-chair batteries".

Lithium ion battery has a large energy density, the average output voltage. Small self-discharge, below 10% per month. No memory effect. Wide working temperature range for - 20 ℃ ~ 60 ℃.Loop performance is superior, can fast charge and discharge, charging efficiency is as high as 100%, and the output power. Long service life. No environmental pollution, known as the green cells.

Charging is one of the important steps, battery repeated use of lithium ion battery charging process is divided into two phases: constant current fast filling stage (light red or yellow) and constant voltage current decline stage (light green).Constant current fast filling stage, the battery voltage rise gradually to the standard voltage of the battery, then under the control chip into the stage of constant pressure, higher voltage is no longer in order to ensure that will not overcharge, current it as battery rise gradually reduced to zero, and the final finish charging. Electricity statistical chips by recording discharge curve can sample to calculate the capacity of the battery. Lithium ion battery after repeated use, discharge curve changes, lithium-ion batteries, although there is no memory effect, but improper charge will seriously affect the battery performance.

Lithium ion battery over charge and discharge can cause permanent damage to is negative. Lead to excessive discharge cathode carbon layer structure appeared to collapse, and failures can cause in the process of charging lithium ion cannot insert; Excessive charging excessive anode carbon lithium ion insertion structure, and cause some of the lithium ion can no longer be released.

Charge is equal to the amount of charging current multiplied by the charging time, in the case of charging control voltage must be, the greater the charging current (charging the faster), the smaller the rechargeable battery. Improper battery too fast and termination voltage control points, also will cause the battery capacity is insufficient, is actually part of the battery electrode active material has not been fully reaction stops charging, the charging the phenomenon of insufficient increased with the increase of cycling times.

Lithium ion batteries battery components:

1, steel shell/aluminum shell series

(1) the battery cover up and down

- (2) the positive active material for lithium cobalt oxide

(3) the diaphragm - a special kind of composite membrane

(4) negative - active substances for carbon

(5) the organic electrolyte

(6) battery shell (divided into two kinds of steel shell and aluminum shell)

2, flexible packaging series

- (1) the positive active material for lithium cobalt oxide

(2) The diaphragm - PP or PE composite membrane

(3) The negative - active substances for carbon

(4) Organic electrolyte

(5) Battery shell, lu: su composite membrane

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