[Science] Advantages and disadvantages of lithium-ion batteries2021-06-23
(1) The voltage is high, and the operating voltage of the single battery is as high as 3.6-3.9V, which is 3 times that of Ni-Cd and Ni-H batteries.
(2) The specific energy is large. The actual specific energy that can be achieved at present is 100-125Wh/kg and 240-300Wh/L (2 times Ni-Cd, 1.5 times Ni-MH). With the development of technology in the future, the specific energy Up to 150Wh/kg and 400 Wh/L
(3) The cycle life is long, generally reaching more than 500 times or even more than 1000 times. For electrical appliances with low current discharge, the battery life will double the competitiveness of electrical appliances.
(4) Good safety performance, no pollution, 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, or mercury 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.
(5) The self-discharge is small. The self-discharge rate of fully charged Li-ion at room temperature is about 10% after 1 month, which is much lower than 25-30% of Ni-Cd and 30-35% of Ni and MH.
(6) It can be charged and discharged quickly, and the capacity of 1C charging can reach more than 80% of the nominal capacity.
(7) The working temperature range is high, the working temperature is -25~45°C. With the improvement of electrolyte and positive electrode, it is expected to be expanded to -40~70°C.
Lithium-ion batteries also have certain disadvantages
(1) The battery cost is relatively high. It is mainly manifested in the high price of LiCoO2 as the cathode material (the resource of Co is less), and the purification of the electrolyte system is difficult.
(2) Do not discharge with high current. Due to the organic electrolyte system and other reasons, the internal resistance of the battery is larger than that of other types of batteries. Therefore, a smaller discharge current density is required. Generally, the discharge current is below 0.5C, which is only suitable for small and medium current electrical appliances.
(3) Need to protect the circuit control.
A. Overcharge protection: Battery overcharge will destroy the positive electrode structure and affect performance and life; at the same time, overcharge will decompose the electrolyte, and the internal pressure will cause problems such as leakage; therefore, it must be under a constant voltage of 4.1V-4.2V Charge.
B. Over-discharge protection: Over-discharge will cause difficulty in the recovery of active materials, so protection circuit control is also required.
(4) Definition of rechargeable battery
Rechargeable batteries, also known as accumulators and secondary batteries, are batteries that can be recharged and used repeatedly. Common ones are: lead-acid batteries (commonly known as "batteries" when used in automobiles), nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries.