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Cylindrical Lithium-Ion Batteries: Evolving to Meet Different Application Requirements

Cylindrical lithium-ion batteries are widely used in applications ranging from IT devices and power tools to micromobility and electric vehicles.

As their applications have expanded, the market has increasingly adopted the 21700 format alongside the established 18650 standard.

More recently, larger 46-series cylindrical cells have begun entering mass production.

This evolution is about more than simply increasing cell size. 

It also reflects the growing specialization of battery cells to meet application-specific requirements for capacity, power output, charging speed, and cycle life.

In this article, we explore the key characteristics of each format and the typical applications of representative Samsung SDI cylindrical battery models.

1. 18650 — The Established Cylindrical Battery Standard

The 18650 is a cylindrical cell measuring approximately 18 mm in diameter and 65 mm in height. 

It has long served as a standard format in the cylindrical lithium-ion battery market.

18650 cells have been used in a wide range of applications, including laptops, IT devices, small electronic products, and various battery packs. 

Samsung SDI's 18650 product portfolio includes models such as the 30Q, 25R, and 25S, which are widely associated with applications requiring high power output, including power tools.

Its standardized dimensions offer practical advantages, including relatively straightforward cell sourcing and battery pack design.

2. 21700 — A Key Format with Application-Specific Performance

The 21700 format measures approximately 21 mm in diameter and 70 mm in height.

Compared with 18650 cells, its larger size allows for greater capacity and power potential per cell, making it an important format for power tools and micromobility applications.

Samsung SDI's 21700 product portfolio can be broadly categorized by application requirements, as shown below.

Even within the same 21700 format, discharge performance, capacity, and cycle life can vary significantly between models. 

Selecting the right cell therefore requires careful consideration of the application's operating conditions and usage patterns.

3. 46-Series Cells — A New Generation of Larger Cylindrical Batteries

How Do 46-Series Cells Differ from 21700?

46-series cylindrical batteries are based on a diameter of 46 mm and represent a larger cell format designed to improve energy capacity and battery pack integration.

The diameter increases from 21 mm to 46 mm, more than doubling the cell's diameter compared with the 21700 format.

Key potential advantages include:

- Higher energy capacity per cell:  A single cell can store substantially more energy than a 21700 cell. 

   Industry comparisons often cite approximately six  times the energy capacity, depending on the specific cell designs being compared.

- Fewer cells per battery pack:  Fewer cells may be required to achieve the same total energy capacity, potentially reducing the number of cell connections.

- Improved pack integration and assembly efficiency :A lower cell count can help simplify pack architecture and reduce the complexity of interconnections and assembly processes.

In March 2025, Samsung SDI announced that it had begun mass production of its 4695 cylindrical battery, measuring 46 mm in diameter and 95 mm in height.

The company reported that initial supplies had begun for a U.S. customer for micromobility applications, with plans to expand into the electric vehicle market in the future.

46-series batteries are expected to find broader applications in areas requiring high energy capacity and efficient system integration, including electric vehicles, electric two-wheelers, and portable power systems.

4. The Key to Choosing a Battery Format Is Application Fit

Each cylindrical battery format offers different advantages depending on the product's requirements.

However, larger cells are not necessarily the best choice for every product.

Battery selection requires a comprehensive assessment of power consumption, required capacity, discharge current, charging conditions, available installation space, and expected service life.

The optimal format and model depend on how these factors interact within the intended application.

Looking for the Right Cylindrical Battery for Your Application?

Alphacell International supports cylindrical battery cell selection and application evaluation based on customers' product requirements and technical specifications.

If you are sourcing cells for power tools, micromobility products, outdoor power equipment, or industrial applications

 please share your target capacity, required power output, operating time, or existing battery model.

Our team can review the relevant specifications and recommend suitable products based on your application requirements.

For inquiries, please contact us via Contact Us or support@alphacell.co.kr.

Thank you

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