Supercapacitors: market factors to consider

Supercapacitors are a promising application for advanced materials such as high surface area nanocarbons, but what are the translational issues and market factors that researchers need to consider to win-over commercial partners? To find out more on the topic, TMR+ spoke with Franco Gonzalez, a senior analyst at IDTechEx and co-author of ‘Electrochemical Double Layer Capacitors: Supercapacitors 2014-2024’ – a 10 year forecast analysing the market, applications, technology, patent and profit trends, and key players in the sector.

Advantages over batteries
Supercapacitors don’t rely on chemical reactions and this gives them several advantages over batteries including a higher power capacity per unit mass, superior operation at low temperatures and extended operational lifetime. Truck-makers are using supercapacitors to guarantee that vehicles will start in very cold weather – a scenario where lead-acid batteries perform poorly as their energy capacity can be reduced by as much as 50%.

The longer cycle lifetimes of supercapacitors compared with batteries can lower system maintenance costs and improve reliability. It makes devices attractive for large resource power applications, particular in remote locations. In wind farms, supercapacitors are used to power actuators that change the blade pitch in high winds to protect the turbines.

IDTechEx senior analyst, Franco Gonzalez

IDTechEx senior analyst, Franco Gonzalez

Energy recovery
Although supercapacitors store less energy than batteries, they can be charged very quickly without detriment (unlike batteries). This makes them ideal for regenerative breaking systems, for example on trains and trams, which convert kinetic energy into electricity. They can also be configured to recover potential energy stored in cranes operating at cargo loading and unloading sites. “At ports, these machines can be in use almost constantly, so it’s a great opportunity for energy recovery,” said Gonzalez. “The need to reduce CO2 emissions is driving the market.”

It often makes sense to pair a supercapacitor and a battery together. “Power surges reduce the energy capacity of a battery,” he explained. “But you can protect it using a supercapacitor.” The combination can be used to extend the lifetime of batteries in renewable energy systems, or in smart phones where power-demand fluctuates depending on the functions in use.

Industry factors
As a general rule, supercapacitors are well-suited to applications with highly-variable power demands. In principle, this means they are a great match for ‘stop-start’ systems fitted to modern cars, which switch-off the engine while you are waiting in traffic or at stop lights and then restart the vehicle when you engage the gearbox. Unfortunately, it’s not that simple.

“Different industries focus on different parameters,” Gonzalez cautioned. “Auto-makers are looking for supercapacitors that are half the price of current devices as they focus on the cost per unit energy and are concerned about the selling price of the car.”

Sales of electric buses and on the other hand are much less sensitive to the initial purchase price as buyers in this sector pay more attention to the total cost of ownership of the vehicle. In this case, because supercapacitors bring down the price per charging cycle, the market is more lucrative for developers.

Today, supercapacitors are more attractive to industrial users that are open to considering the system level cost rather than the cost per unit energy of devices. But, as Gonzalez points out, supercapacitor manufacturers are nevertheless working hard at the material level to reduce price and improve device performance to offer a better cost per unit energy to customers.

Device development
Advances in materials can contribute in a number of ways to making supercapacitors more competitive in the market. Increasing the surface area of the electrodes through activated carbons and nanomaterials will drive up the capacitance and benefit the energy storage capacity of the device. At the same time, finding ways to reduce the resistance (of the active material, the electrolyte, and the porous separator) will boost the power output.

However, it is the operation of supercapacitor cells at higher voltages (V) and finding the right materials to make this happen, which may impact performance in the short to medium term. Both the power and the energy of a capacitor are proportional to V2. “Electrolytes in organic solvents can withstand 2.7 V, but developers are also looking at ionic liquids – room temperature salts – that operate at 5V,” said Gonzalez.

Devices come in many shapes and sizes, and he highlights micro-supercapacitors as a particularly exciting and growing area of research. Gonzalez advises researchers to look at lower-cost materials and manufacturing methods in the first instance. “If you want to use expensive materials then you need to find an application that will pay for that,” he commented. “Researchers need to be aware of how the industry is changing and the relative sensitivity to price of the different applications.”

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Lightning lab to offer full waveform testing by end 2014

Aerospace is a prime destination for materials that are both light and strong, but that’s only part of the story. Translating promising materials into production aircraft brings additional selection criteria into play such as the ability to survive lightning strikes. To find out more, TMR+ visited the Morgan-Botti Lightning Laboratory in Cardiff, Wales – one of the world’s leading facilities in this area.

Zap: high-speed video stills showing a composite panel under test. Credit: Morgan-Botti Lightning lab.

Zap: high-speed video stills showing a carbon composite panel under test. Credit: Morgan-Botti Lightning lab.

The primary focus of the £1.6 million centre, which was set up by Cardiff University in collaboration with AIRBUS Group Innovations, is on the electromechanical characterization of carbon composites, and its goal is to understand and develop safer and more lightning resilient materials.

Using banks of giant capacitors and resistor stacks, the custom-built lab can generate lightning strikes based on protocols such as the EUROCAE ED-84 Aircraft Lightning Environment and Related Test Waveform Standard.

Hot spots
Directing the centre’s activities is Manu Haddad from Cardiff University. In the tour, he explained that the tips of the aircraft such as the wings or nose tend to be targets for the initial strike, but because the plane is in motion the main fuselage will also likely come into contact with the discharge and needs to be protected too.

Samples from Morgan-Botti lightning lab

Test results: carbon composite samples with and without copper mesh (inset).

Today, aircraft makers such as Airbus and Boeing use a copper mesh bonded to the skin of the carbon composite material to disperse the energy from the lightning strike, but this adds weight – typically an extra 3% – and so developers are motivated to optimize their designs and find lighter-weight alternatives.

The lab’s measurement chamber is kitted out with thermal and high-speed cameras to evaluate the dynamic performance of test pieces, and the facility has access to a range of other characterization equipment including scanning electron microscopes.

Electromagnetic issues
Without protection, the top layers of the composite are ripped from the surface as the local area jumps in temperature, which risks overall mechanical failure. Also, designers need to consider the damage caused by electromagnetic radiation penetrating the material, where it could disrupt sensitive equipment below such as wiring loops or sensors.

Resistor stack and capacitor bank for generating lightning waveforms.

Resistor stack and capacitor bank for generating lightning waveforms.

Haddad illustrated how aircraft parts can be modified by showing a composite nose cone fitted with aluminium strips on either side to draw lighting strikes away from the radar equipment often housed in this portion of the plane.

Airbus is a major research partner and played a key role in the lab’s founding back in 2007 together with support from the Welsh government, but today the facility is supporting more than just the aerospace industry. “Wind turbines also need to be protected and we’re working closely with the energy sector on this,” commented Haddad.

Networking opportunities
To encourage collaborative research on the direct effects of lightning on emerging materials, Cardiff University is co-ordinating an international network of academic and industry partners dubbed EMC3 (Electro-mechanical characterization of carbon composites).

For more details on the lab and on becoming a member of the EMC3 network, contact Haddad and his team –

Related reading

Lightning Hazards to Aircraft and Launchers (Aerospace Lab – Issue 5)

Lightning strike protection strategies for composite aircraft (Composites World)

AGU Fall Meeting 2014: Lightning never strikes twice? (

Related links

Advanced High Voltage Engineering Research Centre (Cardiff University)

Video archive – lightning tests (Morgan-Botti Lightning Laboratory)