A ternary lithium battery refers to a lithium battery that uses three transition metal oxides, nickel, cobalt, and manganese, as positive electrode materials. Due to its combination of the advantages of lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide, its performance is superior to any of the above single component positive electrode materials. The following are several common commercial ternary lithium batteries:
1. Ternary polymer lithium battery
Ternary polymer lithium battery refers to the lithium battery whose cathode material is lithium nickel cobalt manganate (Li (NiCoMn) O2) ternary cathode material and uses gel polymer electrolyte. As the transmission medium of ion movement, electrolyte is generally composed of solvent and lithium salt. The electrolyte of lithium secondary battery mainly includes liquid electrolyte, ionic liquid electrolyte, solid polymer electrolyte and gel polymer electrolyte. Gel polymer electrolyte is composed of polymer, organic solvent and lithium salt, which is prepared by mixing organic electrolyte and solid polymer matrix. Because it exists in the form of gelled state, it has the advantages of both solid electrolyte and liquid electrolyte. Because 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, and the thin film provides a large surface area. The thinner the thin film, the higher the energy density, as more active substances can be embedded in the battery. In addition, its electrochemical stability is also very good, and it is resistant to high temperatures. Most high-temperature batteries on the market use polymer electrolytes.
2. Three element power lithium battery
The so-called power battery refers to the battery that supports high rate and high current discharge, has a high power density, and releases more energy per unit of time. The rate discharge capacity refers to the ability of a battery to maintain its capacity when the charge discharge rate increases. The rate of charge and discharge is expressed as xC, where 1C means that the nominal capacity of the battery can be used up in 1 hour, while discharging at a rate of 2C can last for 30 minutes.
The power/rate performance of a battery is closely related to its design and is influenced by various factors, such as electrolyte, separator, type of active material, size of active particles, and so on. Among these factors, the thickness of the electrode is the main factor affecting the high current discharge capacity. The rate discharge capability can be greatly improved by thinning the electrode, as thin electrodes have smaller electronic and ion impedances. However, thinning the electrode results in less active material mass inside the electrode, leading to a decrease in battery capacity. So the main technical challenge of ternary power lithium batteries is to increase their high current discharge capacity without reducing capacity.
For ternary power lithium-ion batteries, Panasonic Corporation of Japan is currently the most researched and technologically mature company. In the experimental stage, it can achieve 30C discharge, and the power 18650 ternary lithium-ion battery, which has been successfully commercialized and mass-produced, has a discharge rate of 12C and a capacity of up to 3300mAh. There are also manufacturers in China that achieve high discharge rates, but the stability of batteries still needs to be improved, especially after a period of use, their cycle life and rate discharge capacity will be greatly reduced. There are research reports that the rate performance of lithium batteries can be improved through methods such as particle coating and modification.
3. Ternary low-temperature lithium battery
The temperature characteristics of a battery are an indicator of its reliability, and its performance can also be evaluated by changing the ambient temperature. The low-temperature characteristics of lithium batteries are mainly evaluated from their low-temperature discharge characteristics and cycle life. The most important aspect of low-temperature batteries is to maintain the fluidity of materials under low-temperature conditions, allowing lithium ions to freely shuttle between positive and negative electrodes, achieving the charging and discharging of the battery. For example, using electrolytes with low melting points to reduce the particle size of the active material will enhance the low-temperature performance of the battery. This is because it increases the channels for lithium ions, which to some extent compensates for the slow movement of lithium ions at low temperatures.
At present, most domestic and foreign manufacturers of ternary lithium batteries can achieve a discharge temperature of -20 degrees Celsius, with a discharge capacity greater than 50% and a cycle life of about 400 times, which can fully meet the needs of ordinary electrical appliances and scenarios. However, in special products such as aerospace and special equipment, or in harsh cold environments such as the north and mountains, lithium batteries must be able to reach lower discharge operating temperatures to meet harsh usage conditions. Dongguan Juda Electronics Co., Ltd. Special Cell Research Institute has gathered a large number of electrochemical experts and industry professors. With a strong research and development team, it has successfully developed ultra-low temperature lithium batteries with a discharge capacity of up to 67% at low temperatures of -40 degrees Celsius, mainly for military and special applications, and has successfully achieved commercial large-scale production.
Experimental analysis shows that three different valence elements form a superlattice structure, and there is a significant synergistic effect between the three components, making the material more stable. The discharge platform is as high as 3.6V, making it one of the most promising cathode materials. Triple element batteries have excellent electrochemical characteristics such as high energy density, good safety and stability, support for high rate discharge, and affordable cost advantages. They have been widely used in the field of small and medium-sized lithium batteries such as consumer digital electronic products, industrial equipment, medical instruments, and have shown strong development potential in the field of power lithium batteries such as intelligent robots, AGV logistics vehicles, drones, and new energy vehicles.