Internal structure and advantages and disadvantages of 18650 cylindrical lithium battery
The 18650 cylindrical lithium battery cell is mainly composed of five parts: metal shell, positive electrode, negative electrode, film and electrolyte. They perform their respective functions to ensure normal charging and discharging. The detailed structure is as follows:
Positive electrode: The positive electrode materials of 18650 cylindrical lithium battery cells are generally lithium iron phosphate, lithium cobalt oxide, etc. The difference of each cathode material will directly affect the characteristics and cost of the 18650 lithium battery.
Negative electrode: The negative electrode material of 18650 cylindrical lithium battery cell includes tin-based negative electrode material, nano-scale negative electrode material, carbon negative electrode material, etc. In the battery, the negative electrode material plays the role of oxidation. Relative potential is low.
Electrolyte solution: Taking lithium iron phosphate as an example, it is divided into solute and solvent. Solute: Lithium salts are often used, such as lithium perchlorate, lithium hexafluorophosphate, and lithium tetrafluoroborate. Solvent: Li-ion batteries often use organic solvents, such as ether, ethylene carbonate, propylene carbonate, diethyl carbonate, etc.
The advantages of 18650 cylindrical lithium battery cells
1. Long cycle life: The cycle life of 18650 lithium battery can reach more than 500 times, which is more than twice that of ordinary batteries.
2. Large capacity: The capacity of 18650 cylindrical lithium battery cells is generally between 1200mah and 3100mah. It should be known that the general battery capacity is only about 800. This is just a single 18650 cylindrical lithium battery cell. If it is combined into a 18650 lithium battery pack, then breaking through 5000mah is not a problem at all.
3. High safety performance: In order to prevent the short circuit of the battery, the positive and negative electrodes of the 18650 lithium battery are separated. Therefore, the possibility of short-circuiting has been reduced to the extreme. High safety performance, no explosion, no burning.
4. High voltage: The voltage of 18650 lithium battery is generally above 3.6 and 3.7, which is much higher than the 1.2V voltage of nickel-cadmium and nickel-hydrogen batteries.
5. No memory effect: easy to use when charging and discharging.
Disadvantages of 18650 cylindrical lithium battery cells
1. Stability: Compared with polymer lithium batteries, 18650 lithium batteries are prone to short circuit or explosion.
2. Do not overcharge: 18650 lithium battery production requires a protection circuit to prevent the battery from being overcharged and causing discharge.
3. High cost: 18650 lithium battery requires high production conditions, which undoubtedly increases the production cost.