Comparison of the differences between cylindrical lithium batteries and square lithium batteries

Cylindrical lithium batteries are divided into three different systems: lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, cobalt manganese mixture, and ternary materials. The outer shell is divided into two types: steel shell and polymer. Different material systems have different advantages for batteries. At present, steel shell cylindrical lithium iron phosphate batteries are mainly used as the main type of batteries. These batteries have high capacity, high output voltage, good charge discharge cycle performance, stable output voltage, high current discharge, stable electrochemical performance, safe use, wide working temperature range, and environmental friendliness. They are widely used in solar lamps, lawn lamps, backup energy, electric tools, and toy models.

Square lithium batteries usually refer to aluminum or steel shell square batteries, and the popularity of square batteries is very high in China. So, what are the differences between cylindrical lithium batteries and square lithium batteries?

Comparison of differences between cylindrical lithium batteries and square lithium batteries

1. Battery shape: The size of the square can be designed arbitrarily, while cylindrical batteries cannot be compared.

2. Multiplication characteristics: Due to the process limitations of welding multipole ears in cylindrical batteries, the multiplication characteristics are slightly worse than those in square multipole ear batteries.

3. Discharge platform: A lithium battery using the same positive and negative electrode materials and electrolyte should theoretically have a consistent discharge platform, but the discharge platform inside a square lithium battery is slightly higher.

4. Product quality: The manufacturing process of cylindrical batteries is relatively mature, and the probability of secondary cutting defects in the electrode is low. In addition, the maturity and automation level of the winding process are relatively high. Currently, the lamination process is still semi manual, which has a negative impact on battery quality.

5. Pole ear welding: The pole ear of cylindrical batteries is easier to weld than that of square lithium batteries; Square lithium batteries are prone to false soldering, which affects the quality of the battery.

6. PACK grouping: Cylindrical batteries have a more user-friendly feature, so PACK technology is simple and has good heat dissipation effect; When packing square lithium batteries, it is necessary to solve the problem of heat dissipation.

7. Structural features: The chemical activity at the corners of the square lithium battery is poor, and the energy density of the battery is prone to decay after long-term use, resulting in a short battery life.

With the rise of automotive power batteries in recent years, the contradiction between car range and battery capacity has become increasingly prominent. Domestic power battery manufacturers mainly use aluminum shell square batteries with higher energy density. Because the structure of square batteries is relatively simple, unlike cylindrical batteries that use high-strength stainless steel as the shell and accessories with explosion-proof safety valves, the overall weight of accessories is lighter and the relative energy density is higher.

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