Can you imagine your cat powering your electric car?
Do you remember petting your cat gently and getting an unexpected electric shock? Have you ever thought why this happens? Have you ever thought you can feed motors with this electric energy?
Cat's fur is good at generating static electricity. The latter is an imbalance of electric charges within or on the surface of a physical material. This imbalance emerges when two surfaces contact and separate and – at least – one of the surfaces has a good resistance to electric current. When you touch the cat, you become the electric conductor and set the electricity “free”. Through your body.
In other words, when your cat rubs against carpets, blankets and couches, its fur (or surface #1) generates and accumulates electricity. The cat gets very fluffy then. It can accumulate thousands volts! These volts can’t break free because of the dry air. The air (or surface #2) simply doesn’t allow them to break free as it’s resistant to currents. And then you touch the cat...
The “problem” with your cat is that its fur does both: generates and discharges energy fast. It can discharge (read: hit you) in a microsecond. Therefore, it has high power density (i.e. fast immediate discharge), but not energy density (i.e. slow gradual discharge). For cars, the latter is much more important (unless you’d like to accelerate brutally fast on short distances).
But the cat’s powering technology can be further improved!
The Chariot Motors company put five innovative electric buses on the streets of Belgrade, Serbia, in 2018. The buses are powered by static energy units, called supercapacitors (or ultracapacitors), which work very similarly to the cat’s fur. They are very fast at charging and discharging. They store energy in electric field. They aren’t li-ion chemical batteries!
Now, you may ask: Why on hell do we keep li-ion batteries then and continue polluting environment? The answer is that the supercapacitors today hold less energy in the same amount of space. And they can’t hold it for long (hours, not days). This means that the Chariot’s e-buses need recharge almost at every bus stop (but the recharge takes seconds). And this means that big supercapacitors work for big buses, not cars.
Buuuuut, good news is coming! The graphene thing was discovered in 2004 in Manchester, UK (and then won the Noble price in 2010)! It is a wonder material consisting of a thin layer of carbon atoms. It is the lightest, strongest, thinnest, best heat- and electricity- conducting discovery ever made. It is ~200 times (!) stronger than the steel and five times lighter! As a supercapacitor, graphene provides an incomparable surface area to its rivals (as it’s one atomic layer thin), what allows it to allocate incomparable volumes of energy in the electric fields. Much more than the furriest cat can handle!
Moreover, you can produce the graphene by yourself! All you need to have is a lump of graphite (f.e. the one from the pencil) and tape dispenser. Put the graphite onto a sticky side, pull it away, and you have the graphene layer “glued” to the tape!
What does the graphene discovery mean for electric vehicles? The leap to the unknown. With its amazing properties, none of the scholars and engineers can predict where the graphene will lead us to. The most modest assumptions are manufacturing energy-efficient cars which can be fully charged in seconds (f.e. on traffic lights). Their chassis will be super-strong and super-light. They will keep on rolling for decades as graphene does not lose its energy-storing capacity with time; graphene does not rust either. These cars will also have no bulky batteries, as you can mount the graphene supercapacitors even inside the steering wheel.
Elon Musk and his chaps are believed to work on graphene supercapacitors for an on-land and outer-space exploration (but they seem to deny this). Chinese company HKG (or Hybrid Kinetic Group) presented their H600 Pininfarina-designed concept with the graphene-rich power-units (805 HP and 1000 km range) in 2017.
Apart from cars, we can also create indestructible human-piloted robots and spaceships!
The bad news, however, is that the graphene researches are in their “teenage years”. There remains a lot of unknown about this material. Its properties are still being discovered. Its properties are tested in combination with other materials. Apart from this, no one knows how to produce it efficiently on the industrial scale.
So, we need to wait. But me and my cat are already very hyped!
Liked the article? Consider joining the Academic Driving tribe:
Here is why I think the li-ion batteries are dead end of electric propulsion:
Here’re my sketch about robo-cars: