What are the advantages and disadvantages of nickel-metal hydride batteries and lithium batteries?

Advantages and disadvantages of nickel-metal hydride batteries: 1. High energy density, 1.5 times that of nickel-cadmium batteries; 2. The battery voltage is 1.2v-1.3v, which is equivalent to nickel-cadmium batteries; 3. No memory effect, Long cycle life; 4. Large current discharge, strong ability to withstand overcharge and over discharge; 5. No pollution, green battery. Disadvantages of nickel-metal hydride batteries: 1. The price is higher than that of nickel-cadmium batteries, and the anode material is rare-earth alloy materials; 2. The self-discharge speed is high. Advantages and disadvantages of lithium batteries: Advantages of lithium batteries a. High voltage: The working voltage of a single battery is as high as 3.7-3.8V (the battery 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 above 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 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 due to metal lithium, which reduces its application fields: 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. Small self-discharge: The self-discharge rate of fully charged Li-ion at room temperature after 1 month storage 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. Now the ferro-phosphorus battery can be charged to 90% of the nominal capacity in 10 minutes. g. High working temperature range: working temperature is -25~55C. With the improvement of electrolyte and positive electrode, it is expected to be expanded to -40~70C. Disadvantages of lithium 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: During overcharging, the excessively embedded lithium ions will be permanently fixed in the crystal lattice and cannot be released again. This leads to short battery life and gas production, causing air drums. 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. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: What is a graphene battery? What are its advantages?