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Towards Structural Batteries

Rendering of a structural battery using carbon fibre yarn as reinforcement and electrode material in the composite. Each strand of yarn consists of 24,000 individual fibres. Illustration credit: Yen Strandqvist

If you open the hood of your car you’ll see, among many other parts, the battery. Take an electric car and you’ll see plenty of batteries.

Researchers and engineers have been at work for a while to remove those batteries and embedding them into the car’s chassis and the bodywork of the car. Now, embedding is probably a bad wording since it gives the impression that you simply move the batteries inside the structure of the car, whilst that is not the point. Rather the goal is to use batteries as the structure of the car.  This is what structural batteries are: a structural component of an object that is able to store and deliver electrical power.

As shown in the picture the idea is to create a material that replaces the car sheet metal doubling up as both energy storage and structural element. In the picture is an example of creating the substitute sheet metal using carbon fibre yarn (this is already used in race sailing boats, both for the sails and for the keel) interwoven with fiberglass acting as insulator and polymers embedding the cathodes and the anodes (in the plural since the sheet will be formed/contains multiple cells).

What could be good for a car can also be good to any other object needing to access power and store it locally (anything that today needs a battery, like our smartphone, an Mp3 player, our car’s key, the television remote control and so on).

The progress in the area of smart materials is leading into this direction. A very nice article has just been published on Wired discussing the status and perspectives of structural batteries.

Europe launched as part of its cooperative research effort an initiative on structural batteries aimed at future electrical vehicle, StorAGE. The research terminated with three demonstrations of a structural energy storage, one in form of a battery and two in form of supercapacitors (these latter formed the hood and the roof of a truck and a car, respectively).

That was back in 2013. Structural batteries were shown feasible but unfortunately not commercially sustainable. It is both the manufacturing aspect that was too expensive and the operating cost. Imagine having a minor accident, hitting or being hit and creating a “dent” in the body of your car. Repair would be extremely expensive since the overall structural integrity would need to be guarantee.

That is why we haven’t seen structural batteries so far. However, manufacturing processes and new smart materials seems to offer new opportunities and these may find application in … unexpected areas: appliances and airplanes! In case of appliances the structural battery can become the external and internal material, making the battery invisible. In case of airplanes (this will take some time) it can become the wings and fuselage solving one of the big problems in creating electric planes; the weight of the batteries. Mind you, structural batteries weight as much as normal batteries, the difference is that this weight will no longer be in addition to the weight of the plane, but it will replace the weight of aluminium, titanium and steel used in the making of the fuselage and wings. The use of carbon fibres can provide the same kind of structural hardness and flexibility of titanium, aluminium, steel (newer airplanes already have a number of parts, including wings, using carbon fibres) and in addition can store energy.

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the New Initiative Committee and co-chairs the Digital Reality Initiative. He is a member of the IEEE in 2050 Ad Hoc Committee. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.