Fuel Cell and Battery Management with Supercapacitors
Supercapacitors are progressing in assisting battery management in modern consumer portable electronics. The first efforts were conducted by Cap-XX some years ago when introducing supercapacitors for camera flashes in mobile phones. At Supercapacitors Europe 2014, Dr Pritesh Hiralal mentioned that this was one of the items that inspired his research at the University of Cambridge. Dr Hiralal opened the conference with his presentation about the integration of supercapacitors into the fabric of flexible printed circuits. This is a supercapacitor which fully integrates with the flexible printed circuit (FPC) production process and can be easily manufactured by any FPC producer. This is one of the many topics IDTechEx has followed during our Supercapacitor series of conferences.
A key finding at the event was that in the future, the electric vehicle industry, regardless as to whether it is hydrogen fuel cells or batteries, both will have longer lifetimes and perform better with supercapacitors. IDTechEx has raised this point since our first Supercapacitor conference when showcasing the Riversimple fuel cell electric car in our conference in Washington in 2012. Last week we had an update on the topic from Imperial College's Dr Billy Wu. He talked about Supercapacitors as Fuel Cell Life Extenders.
According to Dr Wu, supercapacitors in fuel cell cars can:
- Increase 17% efficiency over a pure FC system
- Allows removal of the DCDC converter which reduces the cost of the overall system
- Allows downsizing of the FC (therefore potentially reducing the cost of the car)
- Act as a low pass filter to the FC reducing highly dynamic loads on the FC
- Addresses the issue of PEMFC (Proton Exchange Membrane Fuel Cell) degradation in automotive applications: rapid load cycling and no load idling
By addressing the degradation of the PEMFC, the supercapacitor is effectively increasing its lifetime. Dr Wu mentioned that he had a similar study on lithium batteries.
At our Supercapacitors USA 2013 show, Dr Priya Bendale from Maxwell Technologies revealed a study that confirms the impact of using supercapacitors on battery performance: cycle battery capacity degradation was decreased by a factor of 2 and the impedance degradation reduced by a factor of 6. Why is this relevant? As you know, lithium batteries account for half of the cost of an electric vehicle, and price is still one of the barriers for their mass uptake.
Environmentally friendlier and safer materials
IDTechEx's Supercapacitors Conference has been the forum for presenting new trends in cost effective environmentally friendlier materials and this year was not the exception. One of the main topics is how aqueous electrolyte supercapacitors are closing the performance gap as compared with their organic electrolyte counterparts. In previous conferences we had contributions on this topic from the company Elbit Systems and in this edition of the conference we followed the progress on this topic with Hutchinson (Total Group) and their presentation about safer inorganic based supercapacitors. The French company has avoided the use of organic electrolytes and NMP, hence reducing dramatically the toxicity of the materials used in their supercapacitor assemblies. On this same topic, Professor Beguin from Poznan University of Technology and based on his latest research, showed how supercapacitors using salt aqueous solutions as electrolytes with additives can operate down to -40°C with good charge propagation. Dr Antonio Varsi from WWU Munster did a very interesting contribution in relation to non-active electrode materials. Whilst most of the attention is on active electrode materials, non-active materials such as electrode binders have a strong influence in the manufacturing process. Current binders based on fluorinated materials (such as PTFE and PVdF) are expensive and in environmental terms they are difficult to dispose at the end of the life of the product. Dr Varsi presented a clever process in which cellulose is used as a binder along with ionic liquids to facilitate the electrode coating process.
Because supercapacitors performance does not only rely on electrodes and electrolytes, but also in separators, IDTechEx included a presentation on this topic from Dreamweaver Europe. They spoke about their thin nanofiber separator which can allow high power supercapacitor performance based on their very low resistance. In addition, this product improves supercapacitor safety as it does not consume when set on fire, therefore preventing the contact of electrodes during fire events.
Performance progress in supercapacitors
As usual IDTechEx also presented the latest progress of the leading European supercapacitor companies. Skeleton Technologies presented their production roadmap to Q2/2015 on his new manufacturing site in Bautzen/Radeburg which will be led by Dr Kai Vuorilehto, former manufacturing manager at European Batteries Oy. According to Dr Andrew Burke from University of California, Davis; Skeleton Technologies together with Yunasko have the best performance of supercapacitors.
In this respect Dr Burke from UC Davis spoke about the different methods for measuring performance in supercapacitors and the latest performance results measured in many supercapacitors available in the market. It is worth mentioning that both Yunasko and JM Energy presented performance in their hybrid supercapacitor devices.
New supercapacitor implementations in transport
JM Energy presented some very interesting tests results of the implementation of their ULTIMO Lithium Capacitor (hybrid capacitor) as energy storage solution in hybrid buses. This system comprises 180 prismatic ULTIMO Lithium Ion Capacitors, delivering 0.55 kWh and 135 kW. This system allows a reduction in weight of approx. 200kg, using less volume (150 dm3 less) as compared with a standard symmetric supercapacitor system, allowing both energy delivery and recovery during the bus operation.
Finally, given that developing manufacturing technology is as important as developing new performance materials, IDTechEx offered a space for innovative approaches and solutions in supercapacitor manufacturing. In this topic, VTT presented their supercapacitor manufacturing process by printing technology and the performance of the manufactured product (electrical properties and lifetime). Enerize Corporation spoke about their solutions to test the safety and reliability of supercapacitors during the manufacturing process that replace destructive methods, a very important step in assuring the quality and performance at large scale manufacturing.
IDTechEx's Supercapacitors conference is the place to learn about the latest research in this new emerging energy storage industry. Our next event will be on November 19-20, 2014. www.IDTechEx.com/SCUSA