Do you know what cylindrical lithium batteries are?

Compared with soft packs and square lithium batteries, cylindrical lithium batteries have the earliest commercialization, the highest degree of processing automation, and the lowest current cost of lithium batteries. At present, there are 18650 cylindrical lithium batteries and 21700 cylindrical lithium batteries in the market. Other common cylindrical lithium battery specifications are 14650, 17490, 18650, 21700, 26650 and so on. Cylindrical lithium batteries are divided into different systems of lithium iron phosphate, lithium sulphate, lithium manganate, sulphate manganese mixed, and ternary materials. The outer shell is divided into two types: steel shell and polymer. Different material systems have different advantages. At present, the cylinder is mainly composed of steel-shell cylindrical lithium iron phosphate batteries, which are characterized by high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, large current discharge, stable electrochemical performance, and use Safe, wide operating temperature range, and environmentally friendly. Cylindrical lithium battery structure: The single cell is mainly composed of positive electrode, negative electrode, diaphragm, positive and negative electrode collector, safety valve, overcurrent protection device, insulating part and shell. For the shell, there were many steel shells in the early days, and aluminum shells are the main ones at present. The design of the monomer overcurrent protection device is different from each manufacturer. According to the different safety requirements, the price will be different and can be customized. General safety devices mainly include PTC positive temperature coefficient resistors and fuse devices. PTC, when there is excessive current, resistance heating, and temperature accumulation will increase the PTC resistance value. When the temperature exceeds a threshold, it will increase suddenly, which is equivalent to isolating the faulty cell from the overall circuit and beware of further thermal runaway happened. The fuse device, in principle, is a fuse. When encountering excessive current, the fuse is blown and the circuit is disconnected. The difference between the two protection devices is that the former can be restored, while the latter's protection is one-time. Once a failure occurs, the system has to think that the defective battery cell can be replaced to work normally. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Do you know what are the basic technical indicators of lithium iron phosphate battery packs?