The New K2 3.0V/3000F Cell

The newest addition to Maxwell Technologies’ K2 family of ultracapacitors is the 3-volt, 3000-farad cell. Maxwell’s first 3-volt cell meets the same typical life performance criteria as the 2.7-volt cell, with the added benefit of increased power capability—a 31% increase over the 2.7-volt cell and a 15% increase over the 2.85-volt cell.

Our new 3-volt cell gives customers the flexibility to:
  • Increase available power and energy in the same volume
  • Cost-optimize system designs with fewer cells or modules while maintaining the same power and energy
  • Reduce overall system weight and improve cost-effectiveness in terms of dollars per watt hour
Existing K2 2.7-volt and 2.85-volt cell customers can seamlessly upgrade to the 3-volt cell, which features the industry-standard 60 mm diameter cylindrical design and an electrostatic storage capability that can cycle a million charges and discharges without performance degradation. The cell is available in quick- and easy-to-implement threaded terminals.

As the world leader in ultracapacitor cell technology, Maxwell takes the responsibility to provide its high-volume manufacturing capability so that customers have access to fully reliable and cost-effective energy storage solutions, now and into the future.
"Either used alone or in hybrid configurations with batteries, this new 3V large cell will help to reduce the overall cost and weight of the system and support in attaining operational efficiencies. This product is going to be a game changer for the ultracapacitor industry."

—Vishal Sapru
Research Manager and Growth Consultant, Energy & Power Systems, Frost & Sullivan

Reliable and Economical for all Applications
The 3-volt cell’s higher voltage and increased energy density contributes to overall system optimization and is ideal for a variety of applications, including:
  • Transportation – The 3-volt cell provides overall higher energy density for all transportation applications including hybrid/plug-in hybrid bus and wayside or onboard rail
  • Automotive – Provides extended power and energy availability for longer periods in automotive subsystems
  • Grid – The 3-volt cell provides more energy and more power for grid applications, effectively smoothing voltage dips and enabling frequency regulation

Working with Batteries to Maximize Operational Efficiency
The 3-volt cell can work alone or in tandem with batteries for applications that require both a constant power discharge for continual function and a pulse power for peak loads. In these applications, the 3-volt cell can relieve batteries of peak power functions, extend battery life, reduce overall battery size and cost, and maximize space and energy efficiency in the system.

Resilience in High Shock and Vibration Environments: The DuraBlue® Advantage

The 3.0V cell incorporates Maxwell’s DuraBlue® Advanced Shock and Vibration Technology, which combines Maxwell’s patented dry electrode formulation and manufacturing process with a robust proprietary cell structure. The result: an ultracapacitor cell that meets or exceeds the transportation market’s most demanding shock and vibration requirements. DuraBlue technology increases vibrational resistance by approximately three times and shock immunity by four times when compared to ultracapacitor-based competitive offerings. Maxwell’s 3-volt cell will benefit all applications where ultracapacitors are used in rugged environments. 


  • Highest voltage and power of K2 series
  • DuraBlue® Advanced Shock and Vibration Technology
  • Up to 1,000,000 duty cycles or 10 year DC life*
  • 16 kW/kg of specific power
  • 3.75 of stored energy
  • 60 mm diameter cylindrical design


  • Hybrid and plug-in hybrid bus
  • Grid energy storage (stationary)
  • Wind turbine pitch control
  • Rail (onboard or wayside)
  • Automotive (including hybrid vehicles)
  • Heavy industrial equipment
  • UPS and telecom systems
*Results may vary. Additional terms and conditions, including the limited warranty, apply at the time of purchase. See the warranty details and datasheet for applicable operating and use requirements.