Prismatic LiFePO4 cells are currently the most popular lithium battery for battery DIY enthusiasts. Since electric vehicles (EVs) have become more and more popular, prismatic LiFePO4 cells have gradually become more familiar and are used in more different scenarios. But it seems that few people will understand the cell.
What are Prismatic LiFePO4 Cells?
Compared with cylindrical LiFePO4 cells, prismatic LiFePO4 cells have a shorter history and have only become popular in recent years. Like the name, the prismatic LiFePO4 cells have a prismatic shape and contain all the materials that LiFePO4 batteries have inside, such as electrolyte, LiFePO4 positive electrode, and carbon negative electrode. When these components carry out chemical reactions, they can provide us with a steady stream of electricity.
The Construction of Prismatic LiFePO4 Cells
The structure of prismatic LiFePO4 cells can be divided into internal structure and external structure.
Image: Elithion from Diyelectriccar.com
The interior consists of four parts, the positive electrode, the negative electrode, the electrolyte, and the separator. The internal structure of the prismatic LiFePO4 cell adopts a laminated or wound design to maximize energy storage. The positive electrode material uses an olivine-structured LiFePO4 material, while the negative electrode material uses carbon. There is also a layer of polymer separator between the positive and negative electrode materials. This layer of separator only allows lithium ions to pass through, while electrons can only pass through the external circuit. Transportation, which is why batteries can generate electricity.
The external structure of prismatic LiFePO4 cells is slightly different than that of ordinary cells, but the whole is the same. The battery cell will be designed with an aluminum shell or stainless steel, and there are two wiring ports on the outside of the battery cell, that is, the positive electrode and the negative electrode, which are marked by “+” and “-” respectively. Some battery manufacturers will install two posts at the location of the battery terminal for better use by customers. These two posts are called battery terminals. There is a device with different colors between the external positive and negative electrodes of the prismatic LiFePO4 cells, which we call an explosion-proof valve, or a safety valve. Although LiFePO4 battery is a very safe battery, the existence of an explosion-proof valve is still necessary, which can prevent rare accidents.
In addition, there will be one thing that many people have doubts about, what is the blue or other color film wrapped around many LiFePO4 cells? In fact, this film is a material that can prevent electric shock, that is, an insulating layer, which can well prevent some accidents. In addition, some battery manufacturers will use a battery case to wrap the battery cells, such as CALB. Whether the film or the battery case is used, it is beneficial for the battery manufacturer and the customer.v
In addition, there is an accessory called Busbars, which is a connecting tool for connecting two cells when assembling a battery pack. There are also washers, nuts, etc… to connect into a complete battery pack, these simple little accessories shouldn’t be missed.
The pros of Prismatic LiFePO4 Cells
Compared with cylindrical LiFePO4 cells, it seems that prismatic LiFePO4 cells are more suitable for general customers. Prismatic LiFePO4 batteries will have a relatively high energy density and greater resistance to overcharge and over-discharge, are lighter in weight, and have a square shape that allows for more energy in a limited space, while for DIY hobbies For those, the biggest advantage is that the single-cell energy is very large. At present, the capacity of some mainstream LiFePO4 cells can reach more than 300Ah, which means that DIY is more convenient and it is easier to achieve a large system capacity.
Another very important point is that almost every battery manufacturer is currently researching and developing prismatic batteries, because the history of prismatic batteries is actually relatively short, which means that there is a lot of room for development. Prismatic batteries are evolving, which is a very important advantage.
Prismatic LiFePO4 cells are becoming more and more popular, and are gradually being widely used in many fields, such as home energy storage, signal base stations, marine boats, RVs, etc. Sufficient capacity and excellent performance are being recognized by more and more people, but when using prismatic LiFePO4 cells, it is also very important to understand them well.