With the continuous development of lithium-ion battery technology, cells of various structural forms are widely used in electric vehicles, energy storage systems, and consumer electronics.
Currently, the mainstream lithium-ion battery forms on the market include cylindrical cells, prismatic cells, and pouch cells.
Among them, cylindrical and prismatic cells are particularly prominent in the field of power batteries, and the debate over which is superior has never stopped.
1. Overview of Prismatic Cells
Prismatic cells are enclosed in a metal or aluminum alloy casing, forming a regular rectangular shape.
Due to their compact structure and high space utilization, multiple cells can be efficiently stacked like building blocks, facilitating module assembly.
Depending on the internal structure, prismatic cells are generally divided into two types:
Stacked Type: Offers higher discharge capacity per cell, suitable for high-power applications;
Rolled-Flat Type: Provides higher energy storage and longer cycle life.
Prismatic cells usually have larger capacities, making them suitable for electric vehicles, energy storage stations, and large power systems.
However, due to their larger size, they are not suitable for small devices such as mobile phones or electric toothbrushes.
2. Overview of Cylindrical Cells
Cylindrical cells are housed in a metal cylinder, with internal electrodes precisely wound to form a “jelly roll” structure.
This design not only allows mature and automated manufacturing but also effectively prevents battery swelling during use.
Early cylindrical cells were mostly used in laptops, with 3 to 9 cells per device.
They gained popularity when Tesla used large numbers of cylindrical cells (6,000–9,000) in the first Roadster and Model S.
Today, cylindrical cells are widely used in e-bikes, medical devices, drones, and satellites.
Their structural strength allows them to withstand extreme pressure and environmental conditions, such as in space exploration.
For example, Mars rovers and Formula E electric racing cars both use cylindrical cells.
Advantages of Cylindrical Lithium Batteries
- The cylindrical shape has a large specific surface area, which provides excellent heat dissipation.
- Cylindrical batteries are generally sealed, requiring no maintenance during use.
- The battery casing has high pressure resistance, and does not swell like prismatic or pouch batteries.
- Compared with pouch and prismatic batteries, cylindrical batteries have the longest development history, high standardization, mature technology, high yield, and low cost.
- Mature production process, lower PACK cost, high product yield, and good heat dissipation.
- Cylindrical cells have established a series of international standard specifications, making them suitable for large-scale continuous production.
3. Main Differences Between the Two Cell Types
1. Size and Energy Density
Prismatic cells have larger individual capacities and higher energy density.
A single prismatic cell can often replace dozens of cylindrical cells, providing an advantage in space-limited systems.
Cylindrical cells, being smaller in size with high power density, are more suitable for applications requiring flexible energy output.
2. Electrical Connections and Manufacturing Complexity
Fewer prismatic cells are needed, resulting in fewer welding points and a simpler structure.
This not only reduces manufacturing costs but also minimizes potential welding defects.
Cylindrical cells require more connections and welding steps, but offer advantages in modular repair and flexible configuration.
3. Power Output Characteristics
Cylindrical cells have better discharge capability and can deliver high current in a short time, making them suitable for high-performance applications such as electric racing cars and aerospace equipment.
Prismatic cells emphasize energy storage and endurance, suitable for long-range vehicles and energy storage systems.
4. Industry Trend: The Rise of Prismatic Cells
Currently, cylindrical cells still dominate the electric vehicle market, but prismatic cells are growing rapidly.
With optimized manufacturing processes, prismatic cells can reduce the number of connections while improving production efficiency, thus lowering overall costs.