Analysis of advantages and disadvantages of lithium-ion power lithium-ion batteries

Advantages of lithium-ion power lithium-ion battery a. High voltage: The working voltage of single battery is as high as 3.7-3.8V (cell voltage can be charged up to 4.2V), which is 3 times that of Ni-Cd and Ni-H batteries. b. Large specific energy: The actual specific energy that can be achieved at present is about 555Wh/kg, that is, the material can reach a specific capacity of more than 150mAh/g (3-4 times Ni-Cd, 2-3 times Ni-MH), It is close to about 88% of its theoretical value. c. Long cycle life: generally it can reach more than 500 times, even more than 1000 times, and the lithium iron phosphate can reach more than 2000 times. Regarding electric appliances with low current discharge, the life span of the battery will double the competitiveness of electric appliances. d. Good safety performance: no pollution and no memory effect. As the predecessor of Li-ion, the lithium battery is prone to short-circuit due to the formation of dendrites, which reduces its scope of use: Li-ion does not contain cadmium, lead, mercury, etc. Elements that pollute the environment: A major disadvantage of Ni-Cd batteries of some processes (such as sintered) is the memory effect, which severely restricts the use of batteries, but Li-ion does not have this problem at all. e. Low self-discharge: The self-discharge rate of Li-ion overflowing at room temperature for 1 month is about 2%, which is much lower than 25-30% of Ni-Cd and 30-35% of Ni and MH. f. Fast charging and discharging: The capacity can reach more than 80% of the nominal capacity after 30 minutes of charging. At present, the ferrophosphorus battery can be charged to 90% of the nominal capacity in 10 minutes. g. High working temperature range: working temperature is -25~55°C. With the improvement of electrolyte and positive electrode, it is expected to be expanded to -40~70°C. Disadvantages of lithium-ion power lithium-ion batteries: a. Ageing: Unlike other rechargeable batteries, the capacity of lithium batteries will slowly decline, which has nothing to do with the number of times of use, but with temperature. The possible mechanism is that the internal resistance gradually increases, so it is easier to reflect in electronic products with high working current. Replacing graphite with lithium titanate seems to extend life. The relationship between storage temperature and permanent loss of capacity: storage temperature of charging power 0℃ storage temperature 25℃ storage temperature 40℃ storage temperature 60℃ 40%~60% 2% 2%/year 4%/year 15%/year 25%/ 100%6%/year 20%/year 35%/year 80%/June b. Intolerance of overcharging: When overcharging, the excessively embedded lithium ions will be permanently fixed in the crystal lattice and cannot be released again. This results in short battery life and gas production, causing air bulging. c. Intolerance of over-discharge: During over-discharge, too much lithium ions will be released from the electrode, which can lead to the collapse of the crystal lattice, thereby shortening the life span and causing gas bulging. d. Multiple protection mechanisms are required: Since incorrect use will reduce the life span and may even cause an explosion, a variety of protection mechanisms have been added to the design of lithium batteries. Protection circuit: guard against overcharge, overdischarge, overload, and overheating. Vent: Beware of excessive pressure inside the battery. Diaphragm characteristics: high puncture resistance, guard against internal short circuits; it can melt when the internal temperature of the battery is too high, preventing lithium ions from passing through, blocking the battery reaction, and increasing the internal resistance (to 2kQ). Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Analysis of the advantages and disadvantages of ternary lithium batteries