Ulrik Grape and Pascal Boulanger

Ulrik Grape and Pascal Boulanger

A French startup, spun off from the nuclear industry, is using nanotechnology to make the next generation of battery. NAWA Technologies' Ultra Fast Carbon Battery is a carbon-based ultracapacitor that is claimed to be five times more powerful than existing ultracapacitors. Based near Marseille, the company is also developing 'structural batteries', using the same nanotechnology to turn ordinary items into objects that can hold charge e.g. a smartphone case or a window frame. To learn more about how this green and clean tech could rapidly charge an EV, we spoke to Ulrik Grape, CEO of NAWA Technologies and Pascal Boulanger, COO and Founder of NAWA Technologies. 

How does your Ultra Fast Carbon Battery work and how does it compare to conventional lithium-ion batteries for electric vehicles?

The simple explanation is that in the case of NAWA's technology, the electrical charge (ions) is absorbed on the surface of the carbon nanotubes, then transformed into electrons that are transported with almost no resistance all along the nanotubes, which is one of the main reasons for the ultra-fast charge and discharge we can achieve compared to other technologies. And because the structure of the NAWA carbon nanotubes is vertically aligned (i.e. straight), the charge has even easier path to enter (charge) and exit (discharge). In lithium-ion cells the charge has to first diffuse inside sponge-like tortuous structures which makes the pathway for the ions more cumbersome and thereby slower and then must penetrate the bulk of the structure instead of staying at the surface.

As the ions enter slowly into and exit from the structure, it continuously increases and decreases the volume, meaning that over time the structure will deteriorate (through expansion and collapse), which is one of the reasons why there is capacity loss over time and a limitation on the cycle life. As the lithium ions enter into the structure it can host more energy compared to NAWA's technology, but it also means that NAWA's technology is both more durable (up to one million cycles) and less prone to failure.

We understand that you can achieve different effects depending on the nanotube coating. Is that correct?

Yes, this is correct. While the vertically aligned carbon nanotubes alone have tremendous power capability (we measured a conductivity several hundred times higher than classical batteries allowing ultra-fast charge and discharge), by applying a coating we can increase the energy density of the technology.

There are many different types of electrode coatings that can be used (sodium, titanate, silicon, even lithium), which allows us to offer several types of Ultra Fast Carbon battery, optimising for power density or energy density.

What stage of development have you reached with it?

We are well on the path to industrialising the technology.

NAWA was spun off from the CEA (the French Alternative Energies and Atomic Energy Commission) five years ago with a single proof of concept. Today, the first breed of proprietary equipment to make the carbon nanotubes – designed and developed by NAWA – is already operational in our facility in the South of France, producing electrodes as we speak. The final design for the second-generation equipment is also in place. This will increase the speed and output of the electrodes. In other words, we are well on the path to industrialising the technology.

Will it be cheap and sustainable to produce?

None of the materials we use are rare earth materials or have a negative environmental impact.

Yes, both from the input materials and the production process. In terms of the input materials we use a carbon source and carbon is abundantly available, as well as another material that is also abundantly available. None of the materials we use are rare earth materials or have a negative environmental impact. This ensures that these are low cost. When it comes to the production process we have a unique and proprietary way of making the carbon nanotubes, which is based on the processes from the photovoltaic industry. The other steps in the manufacturing and assembly process are well known from the battery industry. As a result, we should be highly competitive on cost.

Is it possible to operate a car solely using carbon technology?

Yes. Ideally, this would be for city cars that are only used for shorter trips, which is what most of us do daily. The advantage is that the car could have a sufficient range for the city trips, and then could be charged up in just a few minutes, ready to go on the next trip.

This can be extended to other short distance vehicles like buses that would be recharged at stops, boats at each crossing, heavy-duty vehicles in harbours and airports as well as smaller Automated Guided Vehicles (AGV) or Forklifts that are operated in a closed environment like a warehouse. The room for improvement in terms of energy density is also very promising: we believe we could extend the range of these kinds of applications. Nobody knows what will be the future of electric car (batteries, hydrogen fuel cells or wireless continuous charging on road) but whatever the winner, one will need to use a fast charging technology.

To what extent are ultracaps able to take care of acceleration and regenerative braking power surges?

The short answer is better than any technology out there today – this is where the NAWA Ultra Fast Carbon Battery really has its most significant competitive advantage. While a lithium-ion battery may be able to recoup 20-30 per cent of the energy coming from regenerative braking (with the rest lost as heat), NAWA's technology would be able to accept 90 per cent of the energy, store it and have it available for the next acceleration. As a result, a much more efficient use of the energy that is available in vehicles.

The bigger the vehicle the more energy is recouped. For a car braking at low speed, the energy is measured in kilowatts, for a tram or a bus, the energy is measured in megawatts, who knows how much energy we could recoup from a landing aeroplane.

We hear that your carbon ultracap offers some big advantages over traditional lithium-ion battery cells but what are the drawbacks?

The main difference between a lithium-ion battery and NAWA's ultra-fast carbon battery technology is that lithium-ion batteries can store much more energy than our technology.

Although, this is less true when you talk about battery pack size because, historically, we have been compelled to oversize as a result of power peaks, or end-of-life (at the end of its life a lithium battery will have lost 80 per cent of its capacitance) or temperature (at 0°C you have lost more than 50 per cent of your battery energy). Ultra-fast carbon batteries do not need to be de-rated/oversized that much, reducing the gap in terms of available energy.

We do not see our technology as competing with lithium-ion batteries, but rather as complimentary.

Therefore we do not see our technology as competing with lithium-ion batteries, but rather as complimentary. Our technology is superior in terms of fast charging and discharging and handling the peak loads from acceleration and regenerative braking, and overall lifetime, while lithium-ion can take care of the longer duration tasks. There is also the potential advantage that as NAWA's technology takes care of the stressful loads that can cause faster deterioration of the performance of the lithium-ion batteries we can offer a longer life for the whole battery system. In other words, combining the best of both worlds in one battery system.

I will give you a rather extreme example. We have done a simulation on a Formula E battery using data from a co-operation partner of ours, and we've analysed it. When you combine our technology with the lithium battery, we could reduce the size and weight of the battery pack from 300kg to about 200kg– and you'd have a longer driving distance as well because we're much more efficient.

Why do you think the automotive industry has not already made the switch to carbon ultracaps in the EV space?

The reason is probably that there was a tremendous focus at the start of the EV revolution to increase the energy density and thereby the autonomy (driving distance) and to get the cost down to within striking distance of ICE vehicles. This is now more or less achieved, or the path is fairly clear to get there within the next 3-5 years. The attention will now turn to achieve better efficiency from the system and this includes faster charging and discharging, being able to harvest the energy from regenerative braking (high power) better and improving the lifetime (reducing the waste) and reducing the size and thus the cost of the battery system (reducing the environmental footprint and rare earth materials needed). These are the points where NAWA's technology will be highly competitive and provide competitive advantages for the automotive companies.

In addition to automotive, what other applications could make use of your carbon ultracap technology?

We are seeing strong interest and opportunities in the fast-growing Internet of Things (IoT), especially for sensors and transmitting,

We already have initial customers in the power tool market segment, we have a project for the use of our technology in material handling (AGVs) and heavy-duty truck applications for KERS (Kinetic Energy Recovery System), which is all about recuperating the energy from regenerative braking using it for acceleration. We are also seeing strong interest and opportunities in the fast-growing Internet of Things (IoT), especially for sensors and transmitting, where here again it is because those devices will need base energy and peak currents that can be 2,000 times the base load current level.

We are also developing a structural battery concept called NAWA Shell. This integrates our technology into components that would not normally store energy. Potential examples are a smartphone case (giving the user a useful top-up and extending the life of the phone's battery) or the body/chassis of a car (supplementing existing onboard batteries, again improving efficiency and extending battery life). There is huge potential here to completely change our approach to energy storage.

What are the possibilities for ultracaps buried in the road surface?

This is also a very interesting application and we have been in discussions with one of the leading companies in this space. This would be inductive charging and it could be a very attractive solution with the ultracapacitors located in the road surface so that when a vehicle with ultracapacitors onboard passes over the road surface the vehicle is charged up rapidly. One application where this could be especially attractive is for buses, or trams or AGVs.

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