Which raw materials do lithium-ion batteries generally consist of?
Lithium-ion batteries (Li-ion Batteries) are the development of lithium batteries. So before introducing Li-ion, introduce the lithium battery. For example, the button battery used in the previous camera was a lithium battery. The positive electrode material of the lithium battery is manganese dioxide or thionyl chloride, and the negative electrode is lithium. After the battery is assembled, the battery has voltage and does not need to be charged. This battery may also be charged, but the cycle performance is not good. During the charge and discharge cycle, lithium dendrites are easily formed, causing internal short circuit of the battery, so this is generally the case. The battery is forbidden to charge. Later, Sony Corporation of Japan invented a carbon material as a negative electrode and a lithium-containing compound as a positive electrode. In the process of charge and discharge, no metal lithium exists, only lithium ions, which is a lithium ion battery. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode has a layered structure, and it has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity. Similarly, when the battery is discharged (ie, the process we use the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions return to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity. During the charge and discharge process of Li-ion, lithium ions are in a state of motion from positive electrode to negative electrode to positive electrode. The Li-ion Batteries are like a rocking chair. The ends of the rocking chair are the two poles of the battery, and the lithium ions run back and forth in the rocking chair like an athlete. So Li-ion Batteries is also called a rocking chair battery.
Lithium-ion battery component
(1) Battery upper and lower cover
(2) Positive electrode - the active material is generally lithium cobalt oxide
(3) Separator - a special composite membrane
(4) Negative electrode - the active material is carbon
(5) Organic electrolyte
(6) Battery case (divided into steel case and aluminum case)
Lithium-ion batteries have the following advantages:
1) The voltage is high, the working 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, and the actual specific energy that can be achieved is 100-125Wh/kg and 240-300Wh/L (2 times Ni-Cd, 1。5 times Ni-MH)。 In the future, with the development of technology, the specific energy can be Up to 150Wh/kg and 400 Wh/L
3) Long cycle life, generally can reach more than 500 times, or even more than 1000 times. For small current discharge electrical appliances, the battery life will double the competitiveness of electrical appliances.
4) Good safety performance, no pollution, no memory effect。 As a lithium battery of Li-ion's predecessor, it is easy to form dendrites due to metal lithium, which reduces its application: Li-ion does not contain cadmium, lead, mercury, etc。 Elements that are polluting to the environment: One of the major drawbacks of Ni-Cd batteries in some processes (such as sintered) is the "memory effect", which severely constrains the use of batteries, but Li-ion does not have this problem at all。
5) Self-discharge is small, the self-discharge rate of Li-ion fully charged at room temperature after storage for 1 month is about 10%, 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. The 1C charging capacity can reach more than 80% of the nominal capacity.
7) The operating temperature range is high, and the operating temperature is -25~45°C。 With the improvement of electrolyte and positive electrode, it is expected to be widened to -40~70°C。
Lithium-ion batteries also have certain disadvantages:
1) The battery cost is high。 Mainly manifested in the high price of the positive electrode material LiCoO2 (Co resources are small), the electrolyte system is difficult to purify。
2) Can't discharge at high current. Due to the organic electrolyte system and the like, the internal resistance of the battery is larger than that of other types of batteries. Therefore, a smaller discharge current density is required, and the general discharge current is below 0.5 C, which is only suitable for small and medium-sized electrical appliances.
3) Need to protect line control.