Cylindrical and prismatic batteries are two primary packaging forms of
lithium-ion batteries. They are widely used in various fields such as electric vehicles, portable electronic devices, and
energy storage systems. Although their basic working principles are similar, there are some significant differences in design, structure, performance, and applications.
Packaging Shape
Cylindrical Batteries: Typically refer to batteries with a cylindrical shape, such as the commonly seen 18650 battery (18mm in diameter and 65mm in length).
Prismatic Batteries: These batteries have a rectangular or square shape and come in various sizes, which can be customized according to application requirements.
Design and Structure
Cylindrical Batteries: Have standardized sizes and structures, leading to mature and highly automated production processes that help reduce costs.
Prismatic Batteries: Feature flexible structural designs that can be customized in different sizes and shapes according to specific application needs, providing more design flexibility.
Thermal Performance
Cylindrical Batteries: The gaps between cylindrical cells allow for better airflow, improving heat dissipation efficiency.
Prismatic Batteries: Due to their tight arrangement, more complex cooling systems, such as liquid cooling plates, may be needed to maintain optimal operating temperatures.
Energy Density
Cylindrical Batteries: Standardized production helps improve energy density, but their size limitations restrict further enhancements.
Prismatic Batteries: Allow for flexible adjustments according to battery pack designs, offering more space to optimize energy density.
Cost
Cylindrical Batteries: Benefit from economies of scale and a mature supply chain, resulting in lower costs.
Prismatic Batteries: Typically have higher costs due to smaller production scales and higher customization levels.
Mechanical Stability
Cylindrical Batteries: Their structural characteristics provide good mechanical stability and strong impact resistance.
Prismatic Batteries: May require additional structural design to enhance mechanical stability.
System Integration
Cylindrical Batteries: Require more structural components, such as brackets and beams, to secure the cells in battery packs.
Prismatic Batteries: Can be more tightly integrated into battery packs, reducing the number of required structural components and improving volumetric efficiency.
Application Areas
Cylindrical Batteries: Widely used in portable electronic devices, power tools, and electric vehicles. Notable examples include the 18650 batteries used in early Tesla models.
Prismatic Batteries: Extensively used in electric vehicles and large energy storage systems. For instance, BMW i-series and Chevrolet Bolt use prismatic batteries.
Safety
Cylindrical Batteries: Have a good safety record due to their mature structure and production process, though managing safety can be complex when using large numbers of cells.
Prismatic Batteries: Offer a larger surface area for integrating safety features such as safety valves and temperature sensors.
Technological Development
Cylindrical Batteries: Although the technology is mature, they face challenges in increasing energy density and reducing costs.
Prismatic Batteries: With the growing demands for battery performance in electric vehicles, there is more room for technological innovation.
Conclusion
Cylindrical and prismatic batteries each have their advantages and limitations. The choice depends on specific application needs, cost budget, and design considerations. Cylindrical batteries, with their mature technology and lower costs, remain a preferred choice for many applications. On the other hand, prismatic batteries are increasingly favored in electric vehicles and large energy storage systems due to their design flexibility and integration advantages.
