What Is The Difference between A Square Lithium Battery And A Cylindrical Lithium Battery?

What is the difference between square and cylindrical Li-ion batteries?

There are three main types of lithium-ion (Li-ion) batteries: cylindrical, square and soft pack. In the electric vehicle industry, the most promising developments center around cylindrical and square batteries. While the cylindrical battery form has been the most popular in recent years, there are several factors that suggest square batteries may dominate.

Square batteries are batteries where the chemistry is encapsulated in a rigid casing. Their rectangular shape allows multiple cells to be efficiently stacked in a battery module. There are two types of square cells: the electrode tabs (anode, diaphragm, cathode) within the housing are either stacked or rolled up and flattened. For the same volume, a stacked square battery releases more energy at once and provides better performance, while a flattened square battery contains more energy and provides higher durability.Square batteries are mainly used in energy storage systems and electric vehicles. Their larger size makes them unsuitable for use in smaller devices such as e-bikes and cell phones. Therefore, they are more suitable for energy-intensive applications.

Cylindrical batteries are batteries encapsulated in a rigid cylindrical canister. Cylindrical batteries are small and round, so they can be stacked in devices of all sizes. Unlike other battery forms, the shape of a cylindrical battery prevents expansion, an undesirable phenomenon that causes gases to build up in the battery case. Cylindrical batteries were originally used in laptops, which contain three to nine cells. Later, cylindrical batteries became popular when Tesla used them in its first electric cars (the Roadster and Model S), which contained between 6,000 and 9,000 cells.

Cylindrical batteries are also used in electric bicycles, medical devices and satellites. Because of their shape, they are also indispensable in space exploration; other battery forms are deformed by atmospheric pressure. For example, the last Mars rover used cylindrical batteries, and the Formula E high-performance electric race car uses exactly the same batteries as the rover.

The main differences between square and cylindrical batteries:

1. Shape is not the only factor that distinguishes square and cylindrical batteries. Other important differences include their size, number of electrical connections and power output.

2. Size: Square batteries are much larger than cylindrical batteries and therefore contain more energy per cell. Roughly speaking, a single square cell can contain the same amount of energy as 20 to 100 cylindrical cells. The smaller size of cylindrical cells means they can be used in applications that require less power. As a result, they can be used in a wider range of applications.

3. Connection: Since square cells are larger than cylindrical cells, fewer cells are needed to get the same amount of energy. This means that for the same volume, batteries with square cells require fewer electrical connections to be soldered. This is a major advantage of square cells because there is less chance of manufacturing defects.

4. Energy: Cylindrical batteries may store less energy than square batteries, but they have more power. This means that cylindrical batteries can release energy faster than square batteries. The reason for this is that they have more connections per ampere-hour (Ah). Therefore, cylindrical batteries are ideal for high-performance applications, while square batteries are ideal for optimizing energy efficiency.

5. Examples of high-performance battery applications include Formula E racing cars and the Ingenuity helicopter on Mars. Both require extremely high performance in extreme environments.