Nov 08, 2012 Dr Peter Harrop
This article shares some of the research in the new IDTechEx report, Supercapacitor/Ultracapacitor Strategies and Emerging Applications 2013-2025.We establish what is needed to create a billion dollar supercapacitor manufacturer: someone will. A prediction is provided of the coming shakeout in the industry including the number of manufacturers involved. We have investigated the successes and future strategies of 78 manufacturers of supercapacitors and their variants, discovering that, as befits an enabling technology, they are extremely widely applied already, with more to come. Sometimes they replace aluminium or tantalum electrolytic capacitors and often they replace lead acid, nickel cadmium and lithium-ion rechargeable batteries. Reasons include cost of ownership, compactness, reliability, long life and making new things possible, for example making mobile phones and toys cleverer.
Focus of applications
With numbers and interviews, we have confirmed the well-known fact that conventional and electric vehicles are the main focus now. However, by close examination, we reveal strategies that vary from the oil industry to toys as future applications and widespread implementation, notably in East Asia, of use of supercapacitors in remotely reading of utility meters for example. In fact, there is also a strong move to prioritising utility applications, starting at the small devices such as emergency pitch control of wind turbines in storms. This is then moving to large banks of supercapacitors for grid frequency control, power factor correction and smoothing of supply from green energy sources. Company strategies involve creation and piloting of special versions for some of these needs and a trend towards a few large companies buying from a few large suppliers.
Focus of technology
Largely unreported, there is now a spectrum of variants between electrolytic capacitors and rechargeable batteries. This includes a hybrid of a tantalum electrolytic capacitor and a supercapacitor and three forms of variant between a supercapacitor and a rechargeable battery. They are supercabatteries ie. Asymmetrical Electrochemical Double Layer Capacitors (AEDLC) with lithiated anode (entirely electrostatic) or with lithium intercalation in a battery like cathode (partly electrochemical "Faradaic" in action) and the pseudocapacitor. Company strategies typically focus on one or two of these, rarely more. This is linked to the chosen addressable markets that become feasible over the next decade as the business continues to grow rapidly to multi-billion dollar levels and specialisation becomes the order of the day, not horizontal marketing to almost all applications as the leaders attempt today. We detect remarkable lack of strategy and modernisation in many manufacturers, just as very few manufacturers of traditional capacitors or batteries are entering the field even though the supercapacitor threatens their sales. The more alert players, often those new to the business, are content to let the traditionalists sleep on.
In the popular targeting of higher energy density without sacrificing price, life and so on, there is considerable diversity of approaches. Will organic electrolytes be replaced with non-flammable organic versions that are less toxic or is aqueous the only truly green route? Ionic liquids often incorporate both inorganic and organic components: will their advantages outweigh their disadvantages in the marketplace? Will the disadvantages be overcome? How much of the eye-watering theoretical potential of graphene and carbon nanotube active electrodes and their variants will be realised and by when? We track the considerable disagreement on all of this, something now extending to products on sale with disputed characteristics and true costs hidden by special offers. There is even disagreement between those that see symmetrical devices gaining the highest energy density (a minority) and those backing asymmetrical ones for this. They cannot all be right. All the same, no one technology will win given the ever greater diversity of applications.
Forecasting must take into account that it is not just the different types of supercapacitor and variant that are competing with each other, batteries and other alternatives are also improving. To take one example, the pure electric car, to reach lift-off in sales, will attain the necessary affordable 320-480 km/200-300 miles range in ten years because there are so many development routes to this including the following:
• Lithium-ion batteries: Altria 300Wh/kg & Toyota reported by Nikkei as working on 600Wh/kg.
• Graphene supercapacitors: many professors say 1000Wh/kg or more in potential, beyond even the limit of lithium-ion batteries
• Supercabatteries in the form of lithium-ion capacitors
• Lots of little things including multiple energy harvesting, lightweight aerodynamic bodies, composites, more efficient and printed electrics to save 40% of cost, space, weight
However, although supercapacitors will have a part to play in the future success of these pure electric cars, we believe that will not be as the primary source of power even by the end of the coming decade. Supercapacitors will be across the battery in a minority of cases. In our opinion, what will cause the tipping point will be a combination of the first and the last of the options above.
However, cars are the last to adopt most of the new technologies for land, water and airborne vehicles for a number of good reasons, not just conservatism. For example, most of us want our car to act like an urban bus as well as an inter-city bus - two completely different powertrains. We care a great deal about up-front cost but think little about cost of ownership. Recharging must be an open, standardised system with many payment modes - electric boats, aircraft, buses, trucks, trams, trolleybuses and light rail have much simpler specifications in some respects and there is more money available to pay for them.
Only a few years ago, the major automotive and railway rolling stock manufacturers rarely saw supercapacitors as part of their toolkit. However, nowadays almost all of them do. A Siemens view presented in 2012 of the elements of Electrical Bus Rapid Transit eBRT, for example, mentioned supercapacitors as part of the new design toolkit. Supercapacitors and their variants are replacing, or partly replacing other components, particularly rechargeable batteries, this despite their energy density being inferior as yet. As energy density improves - a priority we have observed in research - the pace of replacing batteries will quicken. However, for "fit and forget" opening of doors in emergency, regenerative braking backup and the storage of the regenerative braking energy, supercapacitors already win hands down and their applications increase every day.
For more information see IDTechEx reports Supercapacitor/Ultracapacitor Strategies and Emerging Applications 2013-2025" and Batteries and Supercapacitors for Smart Portable Devices 2013-2023. Supercapacitors are also the topic of an IDTechEx event this week being held in Washington DC - Supercapacitors USA 2012.