In the world of lithium-ion batteries, size and chemical formulation determine everything. From laptops to Tesla vehicles, cylindrical batteries of different specifications play distinct roles. This article will take an in-depth look at three mainstream cylindrical batteries: 18650, 21700, and 4680, analyzing their technological evolution, quality control challenges, and industry-leading testing solutions.
The evolution of lithium-ion cylindrical batteries
18650 battery: pioneer and founder
The 18650 battery was first commercialized by Sony in the 1990s, originally intended to provide longer battery life for video cameras. Its numbering convention (18mm diameter, 65mm length, 0 indicating cylindrical battery) became the naming paradigm for subsequent cylindrical batteries.
It is the "ancestor" of modern cylindrical lithium-ion batteries, with mature technology and a well-established industrial chain, serving as the industry standard for many years.
21700 battery: evolution of performance and efficiency
The 21700 battery, jointly promoted by Tesla and Panasonic, was first applied in the Tesla Model 3 in 2017.Referred to as the "2170" battery, Tesla hailed it as "the highest energy density and cheapest power battery in the world." It strikes the optimal balance between energy density, power, and cost, serving as the new standard for high-performance applications.
4680 battery: born for scale and revolution
The 4680 battery, unveiled by Tesla at its "Battery Day" in 2020, is the core of its electrification strategy.It represents not just a change in size but a system-level innovation. Designed to significantly reduce electric vehicle costs, increase range, and improve production efficiency through larger physical dimensions and new internal design (such as tabless technology).
Advantages of tabless technology:
Ultra-fast Charging: Low internal resistance and heat generation allow it to withstand extremely high charging currents, enabling 5-15 minute ultra-fast charging.
Ultra-high Power Discharge: Capable of instantly releasing massive current to meet acceleration and towing demands of high-performance vehicles like Cybertruck and Semi.
Improved Thermal Management: Uniform heat distribution and lower overall heat generation reduce thermal runaway risks, enhancing safety and lifespan.
Detailed attribute differences between 18650, 21700, and 4680
| Feature | 18650 | 21700 | 4680 |
Dimension | 18mm *65mm | 21mm *70mm | 46mm *80mm |
Typical Capacity | 1800mAh ~3500mAh | 4000mAh ~ 5000mAh | ~9000mAh (est.) |
Energy Densit | Medium (250Wh/kg) | High (300Wh/kg) | Very High (350Wh/kg) |
Power Output | Medium |
High | Extremely High |
Best For | Older tech, DIY | High-drain devices | Next-gen EVs & Storage |
Cost & Availability | Low & Excellent | Medium & Widely Available | High & Limited |
Testing Focus | Material performance research | Consistency and efficiency | High-power characteristics and thermal stability |
Comparison Table of 18650, 21700, and 4680 Battery Data
Technical challenges and quality control: the invisible cornerstone of battery production
With the rapid evolution of battery technology, from 18650 to 4680, quality control in battery production faces increasingly complex challenges. Especially against the backdrop of mass production and new technology applications, high-precision, high-efficiency testing equipment has become crucial to ensuring battery performance and safety.
Quality control difficulties for different battery types
Quality control for 18650 batteries
Despite mature technology, 18650 batteries still face consistency control challenges in mass production. As they are mainly used in consumer electronics, which demand high volumetric energy density and cycle life, each battery requires precise capacity and internal resistance screening.
Quality control for 21700 batteries
As the mainstream choice for power batteries, quality control of 21700 batteries focuses on charge-discharge efficiency and safety. Production lines need to ensure accurate monitoring of battery charge-discharge curves while increasing testing speed to screen out potentially abnormal cells.
Quality control revolution for 4680 batteries
The tabless design of 4680 batteries brings new quality control challenges:
Current Distribution Uniformity: Monitoring becomes more complex after eliminating traditional tab structures
Thermal Management Testing: Need to simulate thermal stability under various extreme conditions
Mass Production Consistency: Increased production variables caused by new processes
These challenges require testing equipment to have higher testing precision, wider measurement ranges, and stronger data analysis capabilities.
Innovation Directions in Battery Testing Technology
Balancing High Precision and Efficiency
Modern battery testing equipment must significantly improve testing efficiency while ensuring accuracy. The application of energy feedback technology allows electricity consumed during testing to be fed back into the grid, reducing energy costs and heat dissipation requirements, creating conditions for high-density testing.
Intelligent Testing Systems
The introduction of LIMS (Laboratory Information Management System) enables automation of testing processes and systematic data management. By integrating testing equipment, environmental control, and data analysis, researchers can focus more on innovations in battery materials and structures rather than tedious testing operations and data collation.
Customized Solutions
Different battery types and applications have varying requirements for testing equipment. Highly flexible testing systems can adapt to full-range testing needs from micro button batteries to large energy storage battery packs, and provide customized configurations based on specific customer requirements.
Cylindrical battery application scenarios and testing solutions
18650 battery:
Consumer Electronics: Laptops, high-end flashlights, drones, early power tools.
Characteristics: Suitable for space and weight-sensitive scenarios where absolute energy requirements are not the highest. Due to their maturity and availability, they are also common in various DIY projects and entry-level products.
Solution: NEWARE CT-9000 series provides high-precision charge-discharge curve analysis, helping researchers optimize electrode material formulations and electrolyte compositions to further improve the energy density and cycle life of 18650 batteries.
21700 battery:
Electric Vehicles: Tesla Model 3/Y, other emerging electric vehicle brands.
High-end Portable Devices: Top-tier power tools, high-power e-cigarettes, ultra-bright flashlights,
portable solar energy storage systems (such as some products from EcoFlow and Jackery).
Characteristics: Currently the best balance between performance and cost, making it the preferred choice for high-end, high-demand applications.
Solution: The CT/CE-4000 series testing equipment integrates high-precision testing modules and automated processing systems,
enabling significantly improved testing efficiency for power cells while ensuring quality, providing reliable guarantees for mass production.
4680 battery:
Electric Vehicles: Tesla Cybertruck, new Model Y, Semi trucks, and other future models.
Large-scale Energy Storage: Fixed energy storage systems like Tesla Megapack, leveraging advantages in low cost and high energy density.
Characteristics: Designed specifically for extremely large-scale, high-performance requirement systems. Its advantages are fully realized only in large battery packs consisting of thousands of cells.
Solution:The high-power characteristics of 4680 batteries place new demands on testing equipment. Specialized equipment like the CT/CE-8000 series offers wide-range testing capabilities from 100A to 1000A, combined with high-precision data acquisition and advanced thermal management systems, providing comprehensive testing solutions for tabless battery R&D and production. In practical applications, such high-performance testing systems have been adopted by several leading electric vehicle manufacturers for
4680 battery quality control processes.
Conclusion
Technological Inheritance and Innovation: While 18650, 21700, and 4680 batteries differ significantly in size and performance, they all based on the same lithium-ion working principle. The tabless design of 4680 represents a technological breakthrough from quantitative to qualitative change.
Key Role of Testing Technology: As battery technology advances, testing equipment plays an increasingly prominent role in ensuring
product quality and driving technological innovation.From laboratory R&D to mass production,professional testing solutions serve as
the critical bridge connecting battery innovation and practical applications.
Future Development Trends: Battery technology will continue moving toward higher energy density, faster charging speeds,and longer cycle life.This requires continuous innovation in testing equipment to adapt to challenges posed by new materials, structures, and processes.
In this rapidly developing field, professional battery testing solution providers, through continuous technological innovation, provide reliable quality control guarantees for battery R&D and manufacturing enterprises, driving the healthy development of the renewable energy industry.
