Take you to understand the principle and characteristics of lithium battery
Issuing time:2021-10-11 09:18
Lithium battery is a battery with lithium metal or lithium alloy as positive / negative material and non-aqueous electrolyte solution. The lithium battery has the advantages of extremely low self discharge rate and gentle discharge voltage, so that the pacemaker implanted into the human body can run for a long time without recharging. The nominal voltage of lithium battery is generally higher than 3.0V, which is more suitable for integrated circuit power supply. Manganese dioxide batteries are widely used in calculators, digital cameras and watches.
With the development of science and technology, lithium battery has become the mainstream. Lithium batteries can be roughly divided into two types: lithium metal batteries and lithium-ion batteries. Lithium ion battery can be charged, and its reliability, specific capacity, self discharge rate and cost performance are better than lithium ion battery. Due to the limitation of its own high-tech requirements, only a few countries' companies are producing this lithium metal battery.
Working principle of lithium battery:
1. Manganese dioxide is generally used as the cathode material of lithium battery, and lithium metal or its alloy metal is used as the cathode material and non-aqueous electrolyte solution. Discharge reaction: LiMnO2 = LiMnO2
2. Lithium battery: lithium ion battery generally adopts lithium alloy metal oxide as positive material, graphite as negative material and non-aqueous electrolyte. The reaction on the charged positive electrode is LiCoO2 = Li (1-x) coo2 XLI XE - (electron). The reaction on the charged negative electrode is 6C XLIX - = lixc6. The total reaction of rechargeable battery is LiCoO2 6C = Li (1-x) coo2 lixc6.
3. The weight of high energy density lithium battery is half of that of nickel cadmium or nickel hydrogen battery with the same capacity. The volume of 20 single lithium ion battery with nickel cadmium high voltage is 3.7V (average value), which is equivalent to three nickel cadmium or nickel hydrogen batteries in series. The pollution-free lithium-ion battery does not contain harmful metal substances such as cadmium, lead and mercury. It is not restricted by the regulations prohibiting the carrying of lithium batteries on passenger aircraft. Under normal circumstances, the charge and discharge cycles of lithium-ion batteries can exceed 500 times and lithium iron phosphate can reach 2000 times. The memory effect without memory effect refers to the decrease of capacity of nickel cadmium battery during charge discharge cycle. This effect does not exist in lithium ion batteries. Fast charging adopts a constant current and constant voltage charger with rated voltage of 4.2V, which can make the lithium-ion battery fully charged within 1.5-2.5 hours; The newly developed lithium iron phosphate battery can be fully charged in 35 minutes. 3、 Advantages and disadvantages analysis 1 advantages (1) higher energy.
Characteristics of lithium battery:
1. The energy storage density of lithium battery is high, which has reached 460-600wh / kg, about 6-7 times that of lead-acid battery; Long service life, up to more than 6 years. The battery with lithium iron phosphate as the positive electrode can be used for 10000 times at 1C (100% DoD); The rated voltage is high (the single working voltage is 3.7V or 3.2V), which is about equal to the series voltage of three nickel cadmium or nickel hydrogen rechargeable batteries, so as to form a battery power pack; The lithium battery can be adjusted to 3.0V through the new technology of lithium battery voltage regulator, which is suitable for small electrical appliances.
2. Lithium battery has high power carrying capacity. Lithium iron phosphate lithium ion battery for electric vehicle can reach the charge and discharge capacity of 15-30c, which is convenient for high-intensity start-up and acceleration; The self discharge rate of lithium battery is very low, which is one of the outstanding advantages of the battery. Generally, it can be less than 1% / month, less than 1 / 20 of that of Ni MH battery; Lithium battery is light, about 1 / 6-1 / 5 of lead-acid products under the same volume; 7) Strong adaptability to high and low temperature, can be used in - 20 - 60 environment, and can be used in - 45 environment after process treatment;
3. Lithium battery is green and environment-friendly. It does not contain or produce any toxic and harmful heavy metal elements, lead, mercury, cadmium and other substances, whether in production, use or waste.
4. Lithium battery production basically does not consume water, which is very beneficial to China, which is short of water. Specific energy refers to the energy per unit weight or volume. The specific energy is expressed in WH / kg or WH / L. wh is the unit of energy, W is watt and H is hour; Kg is the kilogram (unit of weight) and l is the liter (unit of volume).