The packaging form of lithium-ion battery which is better: cylinder cell, square cell, or a pouch cell?

You can see there are various lithium battery types in the market. According to the different battery cell packaging form, the battery is divided into the cylindrical battery, square battery, and pouch battery. Different configurations also mean they have different characteristics, so let professional lithium battery manufacturers take you to have a look at their advantages and disadvantages.

Cylindrical Battery: Long term development, the most mature technology

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Cylindrical battery development is the longest process, the technology is the most mature, its standardization is high as well. And because cylindrical cells have more space between individual cells when they are assembled, they have a big advantage in terms of heat dissipation, and many models with cylindrical cells have adopted lower-cost air cooling technology.

Meanwhile, the cylindrical cell is more flexible, it has 18650, 21700,32650, and other popular models. For the small battery packs, for example, Ebike lithium battery pack in a certain space, the cylindrical battery is easier to assemble and can make full use of space.

But too many batteries also is a tricky problem. Even vehicles with high-energy-density batteries require thousands of cylinder batteries to be put together, which puts more demands on the vehicle’s Battery Management System. In addition, because cylindrical cells are made of steel, they are relatively heavy and, in theory, have a lower energy density than the other two types.

At present, many models on the market have adopted this type of battery, the more representative is the Tesla Model 3, a cylindrical cell of type 21700(where 21 means the diameter of the cylindrical cell is 21 mm, 70 means the length of the cell is 70 mm, and 0 means the type of the cylindrical cell) is used.

Square Battery: Simple Structure, Light Weight

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The popularity of square batteries in China is very high in recent years because the structure of square batteries is relatively simple, the production process is not complicated, and because square batteries do not use high strength stainless steel as shell like cylindrical batteries, so the energy density of square cells is theoretically higher than that of cylindrical cells. More and More Electric Vehicle battery apply square battery.

However, the square cell is usually customized, so it is difficult to unify the production process of the square cell, and its standardization is low. Currently, Celeste ES6, ES8, Dihao EV and other models are using square batteries.

Pouch Battery: high energy density, more flexibility in battery layout

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The pouch battery pack cells are stacked manufacturing process and are thinner in volume than the other two types, so their energy density is theoretically the highest of the three. And because the battery pack is small, it has more flexibility in battery layout than the other two.

But because the battery is superimposed inside, it needs a thin layer between the two batteries, which is filled with liquid and can be heated or cooled to keep the battery at the optimum operating temperature, this also means that flexible battery packs require more sophisticated battery control systems. At present, many AGV batteries and EV batteries apply such type battery.As we know, Cheetah CS9 EV, Linke 01 plug-mix version, Lingke 02 plug-mix version using flexible battery pack.

Conclusion

In the current New Energy Vehicle Market, Cylindrical, Square, Pouch three types of batteries are carried, and there is no absolute good or bad, can only be said to have advantages. In terms of energy density, the pouch battery is the highest, the square battery is the second, and the cylindrical battery is the lowest. Professional lithium battery factory will apply different model cells according to your different application scenarios.

SmartPropel Writer: Nancy

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