Overview of ternary lithium battery

 

There are many kinds of anode materials for lithium ion batteries. According to the different anode materials, they can be divided into lithium cobalt acid, lithium manganese acid, ternary materials, lithium iron phosphate and lithium titanate. Ternary lithium battery refers to the lithium battery which USES three kinds of transition metal oxides, namely nickel, cobalt and manganese, as the positive electrode materials. Because it combines the advantages of three kinds of materials, namely lithium cobalt acid, lithium nickel acid and lithium manganese acid, its performance is better than any of the above single component positive electrode materials. Experimental analysis shows that three different valences of elements form a superlattice structure, and there is an obvious synergistic effect between the three components, which makes the material more stable, and the discharge platform is as high as 3.6v, so it is considered as one of the most promising cathode materials. Ternary battery with high energy density, good stability and safety support high rate discharge excellent electrochemical properties, such as cost advantage and price moderate, in consumer digital electronic products, industrial equipment, medical equipment, and other areas of the small and medium-sized lithium battery won the widely used, and in intelligent robot and AGV logistics vehicles, unmanned aerial vehicles and new energy vehicles such as power lithium battery field showed a strong development potential.

 

At present, the research on ternary materials mainly focuses on the preparation of precursor, the synthesis of materials and the relationship between electrochemical properties and structures. Most of the transition metal elements in the material Ni, Co, Mn, respectively to + 2, + 3, + 4 valence state exists, in the process of charging and discharging, electrochemical reaction and Co3 + and Ni2 + / Ni4 + / Co4 +, Mn basic don't participate in the electrochemical reaction, just have the effect of stable material structure. As for the preparation methods, the commonly used synthesis methods in industry are: high temperature solid phase method, coprecipitation method, sol-gel method, hydrothermal synthesis method, combustion method and so on. Ternary material is a kind of superior comprehensive performance of lithium battery cathode material, within a certain range to change the molar ratios of three kinds of materials, and add the corresponding additive (binder, conductive agent, the collection of fluid, etc.), can be in one area for outstanding performance characteristics, such as ternary lithium battery power type, type of ternary lithium battery capacity, cryogenic ternary lithium battery and so on.

 

The ternary polymer lithium battery

Ternary polymer lithium battery is correct material using nickel cobalt manganese acid lithium (Li (NiCoMn) O2) ternary cathode material, and using the gel polymer electrolyte of lithium battery. As the transmission medium of ion movement, electrolyte is generally composed of solvent and lithium salt. Electrolyte of lithium secondary battery mainly includes liquid electrolyte, ionic liquid electrolyte, solid polymer electrolyte and gel polymer electrolyte. The gel polymer electrolyte is composed of polymer, organic solvent and lithium salt. In the form of gel, it has the advantages of both solid electrolyte and liquid electrolyte. As the electrolyte is limited in the polymer chain, it also has high ionic conductivity (up to 10-3s /cm) in a wide temperature range. Its biggest advantage is the high mechanical strength of the diaphragm, film provides a large surface area. The thinner the film, the higher the energy density, because more of the active material can be embedded in the battery. In addition, its electrochemical stability is also very good, high temperature resistance, most of the high-temperature batteries on the market are using polymer electrolyte.

 

 

Ternary lithium battery

The so-called power battery refers to the battery support high rate of large current discharge, high power density, the release of more energy per unit time. Discharge capacity refers to the charging and discharging rate increase, battery capacity of keeping ability. Charging and discharging rate expressed in xC, 1 c means the nominal capacity of battery can be finished in 1 h, and with 2 c discharge is available for 30 min.

 

The power/power performance of the battery is closely related to the design of the battery, and is affected by a variety of factors, such as electrolyte, membrane, type of active material, size of active particles, and so on. Among these factors, the thickness of electrode is the main factor affecting the capacity of large current discharge. The power of a multiplier discharge can be greatly improved by thinning the electrode, which has a smaller electrical and ionic impedance, while thinning the electrode leads to less active matter mass in the electrode and therefore a reduced battery capacity. So the ternary power lithium battery main technical challenge is not to reduce capacity increased under the condition of large current discharge capacity.

 

For ternary lithium battery, the company with the most research and the most mature technology is panasonic of Japan. In the experimental stage, it has been able to achieve 30C discharge, among which the power 18650 ternary lithium battery which has been successfully commercialized for large-scale production has a discharge rate of up to 12C and a capacity of up to 3300mAh. There are also domestic manufacturers to achieve a higher discharge rate, but the stability of the battery still needs to be improved, especially in the use of a period of time, its cycle life and discharge rate capacity will be greatly reduced. It has been reported that particle coating and modification can improve the multiplier performance of lithium battery.

 

Ternary low temperature lithium battery

 

Battery temperature characteristics are indicators of battery reliability, and battery performance can also be evaluated by changing the ambient temperature. The low temperature characteristics of lithium battery are mainly investigated from the low temperature discharge characteristics and cycle life. The most important thing of low temperature battery is to maintain the fluidity of materials under low temperature conditions, so that lithium ions can freely shuttle between the positive and negative poles to realize the charge and discharge of the battery. Such as the use of low melting point of electrolyte, reducing particle size of active material, will enhance the low temperature performance of the battery, this is because increased the lithium ion channels, to some extent makes up the defect of the low temperature lithium ions move slow.