Comparing Pouch and Cylindrical Cell Performance
Badland Batteries products are made with high-performance pouch cells
When it comes to battery manufacturing, there are two primary methods of cell structure – pouch and cylindrical. Both have benefits and drawbacks, with operational needs typically lending themselves to one cell type over the other, but from a pure performance stance, pouch cells are typically the better solution in most cases. This is because aside from the obvious differences in shape, there are also significant performance differences that define pouch versus cylindrical cell design.
First, let’s tackle the physical shape and size of the cells. Cylindrical are exactly what they sound like – cylinder-shaped cells, whereas pouches are typically rectangular and flat. Due to their shape, pouch cells can be tightly packed whereas cylindrical cells will naturally leave gaps as they are arranged in a pack. Because of this, cylindrical cells are not only more difficult to fit into compact or irregular shaped battery formats, but they also tend to be larger than a pouch cell equivalent battery pack. Weight is also a key consideration as materials such as the metal casings used for cylindrical assemblies are heavier than their pouch cell counterparts.
When it comes to performance, pouch cells are the superior choice for energy density and C-rate. Because pouch cells have a thin laminate shell versus the metal casing of a cylindrical cell, it means pouch cells have more energy per unit. For example, approximately 8-12% of the total mass of a cylindrical cell is the casing whereas it’s only 2-3% of a pouch cell. This means more of the mass is reserved for the cathode, anode, and electrolyte – providing higher energy density.
The C-rate is also higher in pouch cells because there is more surface area for ion exchange and current collection compared to a tightly wound cylindrical cell. With the electrodes stacked in flat layers, current paths are more uniform and dramatically shorter, leading to lower impedance and longer cycle life. The pouch format also lends itself to better toleration of expansion and thermal stress, as well as more rapid adoption of new technologies due to flexibility of the stacking process compared to the winding process used for cylindrical cells. Some cylindrical cells do have a high C-rate, but they also have a temperature cutoff limitation for the discharge currents specified due to the thermal limitations of the packaging so you can’t actually do a full discharge at the rates specified.
Finally, from a cost perspective cylindrical cells can be cheaper because they are mass produced. However, they also tend to not have the same types of quality testing as pouch cells and you will need more cells per battery which adds labor and points of failure during the assembly process. Pouch cells for Badland Batteries products are serialized and go through rigorous testing with traceability from the product serial number to the individual cells that go into it.
In general, pouch cells are a fantastic choice for drone batteries. If you’re looking for a high-powered, high-performance, high-quality battery solution, packs such as the Badland Batteries 17000mAh 12S or 6S made of cutting edge pouch cells are the superior choice.