The concept of the electric vehicle has been around for over two hundred years. In 1828 Hungarian inventor Anyos Jedlik designed and built a small model carriage, complete with electric motor. This sparked a mini-evolution over the next century or so, with many inventors and pioneers creating electric-powered vehicles, including one Ferdinand Porsche, whose very first car, the P1, was an EV (Electric Vehicle) – take that Mr Musk. In fact, until Henry Ford came along and changed the game in 1908 by using something called the internal combustion engine, electric power was the source of choice for the fledgling car industry.
And then? Not a lot. Electric powered vehicles were pretty much ignored until the 1960s when the first mumblings of climate change caused by car emissions became a ‘thing’. It wasn’t until 1997 that a hybrid became available (take a bow Toyota), and Tesla launched their first commercial model in 2008. We now find ourselves are in the middle of an EV revolution, car manufacturers falling over themselves to gradually switch their models to hybrids or full electric. When viewed objectively it’s clear that the EV industry is still very young – and while the technology is accelerating exponentially, there are still challenges. Charging infrastructure is currently woeful, many models are still financially beyond the average buyer, there are few incentives for switching and range anxiety is a big issue.
This last point is possibly the biggest factor in attracting new users, and how far a car can travel before requiring a recharge is mostly down to the batteries employed. There are three types of battery used in EVs – ‘traditional’ lead-acid which have been around since the 1800s; nickel metal hydride (NiMH) and lithium-ion (Li-ion). Of these, the Li-ion type is fast becoming the de-facto choice for EVs due to their extremely high energy density – in other words they hold lots of energy in a small space – they are light, portable and are by far the best at retaining charge when not being used (this is called self-discharge). There are some issues related to lithium batteries however. They can get incredibly hot and have been known to burst into flames, staying alight for days. Not a good look for an EV.
To date, engineers have used layers of glass, plastic or air insulation as a guard against excess heat – and generally these work well in laptops, smartphones and EVs. But as the race to increase EV range and power accelerates, so does the risk. Researchers across the globe have been looking into how to make lithium batteries completely safe, even more efficient and cheaper to produce.
The answer may well come from nanotech; Stanford University have recently published a paper* which demonstrated how stacking several atomically-thin sheets of nanoparticles above hot spots has the same effect as that of glass – but is up to one hundred times thinner. The more efficient the heat exchange, the more power can be squeezed from the batteries – safely. This approach is still in its early stages but could help to increase EV range over time.
Another challenge with Li-ion batteries is chemical ageing – we see this in laptops and particularly smartphones, and although EV batteries are far more robust, the ageing issue still persists due to chemical reactions between the negative electrode and electrolyte. In addition, where in the world an EV is driven can also have a bearing. Li-ion ageing can also be affected by particularly cold or warm climes. At present there is no fixed solution for this, but advances in both cathode compounds and silicon compound anodes could help – although one tends to offset the other (cathode compounds improve performance and life cycle, whereas silicon anodes increase energy density but also mechanical degradation).
One interesting area of development is that of combining the use of special nanoparticles with any of the previously mentioned solutions. There are nanoparticles in existence that are incredibly efficient at absorbing heat, reducing the affects of chemical reaction within a battery or harnessing energy. If such nanoparticles can be put into a coating-like solution and deployed as part of battery development, the era of EVs getting us far further down the road might not be too far away.
Sharc Matter is a nano-based technology using silica nanoparticles that can be used across many different applications. For more information please visit www.sharcmatter.com