AABC 2014 ECCAP Symposium - Large EC Capacitor Technology and Application - Session 2

Today supercapacitors are no more the Cinderella of power supply but can be considered as a proven technology that covers many applications related with load leveling the batteries, regenerative braking or various backup systems to compensate short-term voltage surges or drops. Still there are many directions for technology improvements and, being aimed at developing the best SC devices, Yunasko team’s efforts are focused at:

• further reducing the internal resistance in order to increase the SC efficiency and power output;
• developing the hybrid devices with their energy density of about 40 W.h/kg and/or cycle life of the order of 10⁵ charge-discharge cycles;
• increasing the operating temperature limit up to 100 °C;
• increasing the working voltage up to 3V;
• reducing the cost of SC devices.

Cost reduction can be achieved due to both performance improvement and the use of low cost but still effective components. Some most recent results will be presented in our talk.

There are cities with hundreds, thousand and even tens of thousands of municipals buses circulating, hundreds of Kilometers every day.
Buses have to work under very stringent conditions, where the engine is not allowed to obtain the best working efficiency.
They have to operate with many stops, short distances between stops and at very low fuel economic conditions.

Aim:

1. Cost Reduction in the fuel Cost.
2. Reduction of the pollution produced by Municipal buses.

Project stages:

1. Understand the everyday working conditions of municipal buses.
2. Collecting and interpretation the data and the interpretation.
3. Design and test prototypes
4. Comparing before and after of the results.
5. Design an automatic system that meets the starting aim and satisfy the customer’s needs.
6. Market the final solution.

Ultracpacitor technology has long been a technology of promise and debate in transportation. This talk is intended to provide insights into recent and rapid adoption of Ultracapacitors in a vast array markets and applications. Consumer demand, Governmental policy, and superheated competition in commercial markets have become market drivers for reduced emissions and continued innovation in the Automotive, Trucking, New Energy Bus, Train and Rail Markets to mention just a few. As Ultracapacitors “cross the chasm” and demand increases at exponential rates Maxwell readies itself for the next phase of growth and innovation.

High power is the main reason for applying electrochemical capacitors. Power is limited by the inner resistance of the capacitor. However, there are many definitions for the inner resistance; data sheets, impedance spectroscopy measurements and cycling experiments give quite different numbers for the resistance.

The alternating current (AC) resistance is rather easily determined by measuring the impedance at 100 Hz frequency. The AC resistance value corresponds to the contact resistance of tabs, welds, current feeders and aluminum/carbon contacts. Additionally, the electrolyte resistance inside the separator causes contact resistance.

The direct current (DC) resistance includes the AC resistance and the electrolyte resistance in the porous carbon structure. The measurement is less straightforward, and the result depends on current and time.

In this presentation, various components of the resistance are discussed:

• tabs
• welds
• aluminum foil
• aluminum/carbon contact
• electrolyte in the separator
• electrolyte in the porous carbon.

Some methods for resistance measurement are shown:

• 10ms method
• 5s method
• impedance spectroscopy
• capacitor cycling

Finally, the importance of resistance for different applications is discussed.

This presentation discusses ultracapacitor technologies, describes the different commercial offerings, their relative pros and cons and the markets they serve.

The industry expectation is for higher performance and lower cost. The presentation will try to normalize these two attributes with respect to application.

Finally the path forward. How will the industry keep up with technology as the solution?

Demand of ESS ( Battery or Ultracapacitor ) have been increasing for advanced vehicle application such as Micro Hybrid/Start_Stop, Mild Hybrid, EV, PHEV, and Full HEV because of the global requirement for the minimization to the environmental impact, improvement of fuel consumption and GHG emission reduction.  The price reduction and the performance improvement would be serious requirement in the automotive industry to implement ESS into the advanced vehicles mentioned above. Here in the presentation will be discussed the cost, new DLCAP,  roadmap and the outcome.

Focusing pints here in this presentation are:

• Cost trend
• New development for automotive application
• Outcome

Energy storage in electrochemical capacitors is of great interest because of its high reversibility, long cycle life, and safe operation.  Global activities continue to develop improved materials offering higher performance and increased durability.  However, a testing platform is needed for the new advanced materials and for developing a better understanding of normal degradation processes.  We have built the Case Capacitor Prototyping Facility (CCPF) at Case Western Reserve University in Cleveland Ohio to evaluate advanced electrochemical capacitor materials.  Materials are evaluated for their functional performance in nominal 100-F-size, spiral-wound prototype cells, which is a common commercial mid-size product.  Carbon electrode materials, electrolyte, separator, additives, and package seal materials can be evaluated using these test vehicles.  The facility’s equipment and processing capability allows mixing of electrode materials, electrode slurry coating on a foil substrate, roll calendaring, current contact tab attachment, roll winding of coated foils and separator into a bobbin, bobbin drying, electrolyte addition and package crimp sealing under dry conditions, and package labeling.  Fabricated prototype devices allow initial electrical property and performance measurements of specific materials or designs as well as the long-term stability and durability testing of construction materials.

Within a few days the Case Capacitor Prototyping Facility is able to produce many tens of nominally identical cells and thus allow collection of statistically significant information to aid in the optimization of advanced construction materials.  A goal of the CCPF, in addition to the training of students and supporting fundamental materials and performance research, is to facilitate commercialization of advanced electric double layer capacitor materials by providing functional performance information consistent with general industry needs.
We will describe this facility, discuss its capabilities in detail, and present examples of performance information for capacitor devices fabricated using typical commercial materials.

• The motivation for building the Case Capacitor Prototyping Facility
• A description of the processing steps and capability of the facility
• Examples of an experimental design and testing results of fabricated capacitors
• How the facility can be used to advancing capacitor developement

Automakers have been mass producing hybrid electric vehicles (HEVs) for well over a decade, and the technology has proven to be very effective at reducing per-vehicle gasoline use. However, the battery cost in HEVs contribute to higher incremental cost of HEVs (a few thousand dollars) than the cost of comparable conventional vehicles, which has limited HEV market penetration. Significant cost reductions/performance improvements to the energy storage system (ESS) can improve the vehicle-level cost vs. benefit relationship for HEVs. Such an improvement could lead to larger HEV market penetration and greater aggregate gasoline savings. After significant analysis by the National Renewable Energy Laboratory (NREL), the United States Advanced Battery Consortium (USABC) and Department of Energy (DOE) Energy Storage program suggested a new set of requirements for ESS for power-assist HEVs for cost reduction without impacting performance and fuel econmoy significantly. This was based on the NREL's conclusion that significant fuel savings could still be delivered from an ESS with much high-power, lower energy ESS. USABC issued a new set of lower-energy ESS (LEESS) targets that could be satisfied by a variety of technologies, including high-power batteries, ultracapacitors, or asymmetric capacitors. With support from DOE, NREL has developed an HEV test platform for in-vehicle performance and fuel economy validation testing of the hybrid system using such LEESS devices. This poster will describe development of the LEESS HEV test platform, and LEESS laboratory as well as in-vehicle evaluation results. The first LEESS technology tested was lithium-ion capacitors (LICs)—i.e., asymmetric electrochemical energy storage devices possessing one electrode with battery-type characteristics (lithiated graphite) and one with ultracapacitor-type characteristics (carbon). We will discuss the performance and fuel saving results with LIC with comparison with original NiMH battery.

The supercapacitor is the only energy storage device that stores electricity in the same form—ELECTRICITY!! The battery, in contrast, stores electricity in the form of chemical energy. This fact has profound implications for the response speed and the life of the device.

Batteries are much slower to deal with pulse inputs and outputs, and their life under pulse loads is seriously degraded.  This could be the case for the acceleration and braking of Electrical Vehicles, and pulse discharge during wireless transmission of sensor networks, M2M and so forth. Supercapacitors thrive under these conditions. They both extend the life of batteries, and in some cases, by combining with energy harvesters, entirely replace batteries. 

This study focuses on the enhancement of performance and life of Lithium Ion coin cells used for pushing electrical signals wirelessly using the OptiXtal’s small supercapacitors, which are unique in not being cylindrical, but being flat, ultrathin and flexible. They are also one of the smallest supercapacitors in the world. In many cases, the form factor, size, and shape of the supercapacitors allow custom build a supercapacitor to fit the existing space, thus eliminating a costly package redesign.

By combining a supercapacitor with an energy harvester, sensors, and wireless communicator, OptiXtal has already developed a self-sustaining battery-free system, which seems to be the first in the world.  This system is useful in wireless sensor networks (WSNs) where the cost of replacing dead batteries can be a major cost center.

This study will demonstrate a Building Energy case, and show data on its use to understand and motivate demand side consumption of building energy.