What are Tabless Battery Cells? A Technical Deep Dive

The demand for higher-performing lithium-ion batteries has never been greater, driven by the growth of electric vehicles, renewable energy storage, and advanced next-gen applications. As traditional cylindrical cells such as 18650 and 21700 reach their engineering limits, the industry is innovating with new designs that reduce inefficiencies and improve scalability. Among these innovations, tabless battery cells stand out as a breakthrough in performance, safety, and manufacturability. 

In this article, we’ll explore what tabless cells are, why they matter, and how their technical design addresses the limitations of conventional tabbed cells. 

Understanding the Basics: The Role of Tabs in Cylindrical Cells 

A cylindrical lithium-ion cell is essentially a jelly roll – a spirally wound structure of anode, cathode, and separator layers. In conventional cells, current is collected through tabs: strips of conductive metal (nickel, copper, or aluminum) welded at specific points on the electrodes. 

• Anode tab: connects the negative electrode to the cell can. 
• Cathode tab: connects the positive electrode to the cell cap. 

These tabs act like “doors” through which current enters and exits the electrode. However, because tabs are discrete and localized, the current flow must travel across the entire electrode sheet toward a few exit points. This creates longer internal pathways, higher resistance, and uneven current distribution.

What Makes a Cell “Tabless”? 

In a tabless cell, the electrodes are not restricted to just a few tabs. Instead, the current is collected continuousl along the edges of the jelly roll. This is done by notching or extending the electrode foils so that the entire edge is in direct contact with a current collector plate or the cell housing. 

In simple terms: 

• Tabbed design = few narrow exits for current. 
• Tabless design = the entire edge acts as a continuous tab.

This drastically reduces the bottlenecks inside the cell. 

Why Tabless Matters: Technical Advantages 

1)Reduced Internal Resistance 

• In tabbed cells, electrons must travel long distances through the electrode foil to reach the tab. 
• In tabless cells, current exits almost immediately through the continuous edge, shortening the pathway. 
• This reduces ohmic resistance, measured in micro-ohms, allowing higher current output. 

2)Better Thermal Management 

• Localized tabs create “hot spots” as high current flows through small areas. 
• Distributed connections spread the heat evenly across the electrode edges. 
• Result: cooler operation, lower risk of thermal runaway, and improved cycle life. 

3)Higher Power Capability 

• Lower resistance enables higher charge/discharge rates. 
• Cells can sustain fast charging with reduced degradation. 

4)Scalability in Larger Formats 

• As cylindrical cells grow (21700 → 4680), electrode length increases quadratically. 
• Longer electrodes in tabbed designs cause non-uniform current distribution. 
• Tabless designs solve this, enabling larger cells without proportionally higher resistance. 

Technical Insights: Jelly Roll Geometry and Resistance 

The jelly roll’s geometry plays a critical role in performance: 

• In tabbed cells: The winding diameter increases with every layer. Tabs compress certain areas, creating mechanical stresses and inhomogeneous coating thickness.  
• In tabless cells: Electrode edges remain more uniform, reducing localized stress. 

Resistance analysis: 

• Typical single-tab 18650 cells show ohmic resistance between 15–36 mΩ. 
• Multi-tab 21700 cells reduce this to ~10 mΩ. 
• Tabless cells achieve much lower internal resistance, often below 6 mΩ, enabling higher current flow, reduced heat generation, and better cycle life. 

Energy Density and Performance 

Interestingly, tabless design is not primarily about increasing energy density—it’s about improving power delivery and thermal stability. 

• Gravimetric energy density (Wh/kg) may remain comparable to tabbed cells. 
• But the usable energy at high C-rates (fast charge/discharge) is significantly higher in tabless cells because less energy is lost as heat. 
• Tabless also enables safer scaling, so manufacturers can increase electrode thickness and overall cell capacity without hitting thermal limits. 

The 5000T Series: Tabless Design in Action 

At Trydan Tech, the 5000T series represents a practical application of tabless cylindrical architecture. This cell combines high capacity with high power delivery by leveraging continuous current collection along the electrode edges. The result is lower resistance, better thermal stability, and higher sustained performance compared to traditional tabbed cells. 

Applications such as drones, e-mobility, and high-drain industrial equipment benefit directly from this design, gaining extended runtimes, faster charging, and reliable high-power bursts without compromising safety. With the 5000T series, tabless technology is no longer a concept—it’s a reality powering next-generation solutions. 

Conclusion 

Tabless cells represent a fundamental shift in cylindrical battery design. By eliminating discrete tabs and enabling continuous current collection, they reduce resistance, improve thermal management, and unlock higher performance at larger scales. 

While not all designs on the market today are fully tabless, the industry is clearly moving in this direction. For applications requiring fast charging, high power output, and safe thermal behavior, tabless cells will be the foundation of next-generation battery applications. 

As research advances and manufacturing matures, we can expect to see true fully tabless designs that redefine performance standards for the future of energy and electrification.