Motor Mouth: Is this the breakthrough EVs have been waiting for?
Superconductors promise faster charging, greater efficiency, and greatly increased battery life, but can they really work?
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A week ago, a small South Korean research firm, Quantum Energy, rocked the geek-o-sphere. We’re talking the nerd equivalent of I-got-a-secret-portal-to-Taylor-Swift-tickets, here. If there were such a thing as an engineering equivalent of TMZ or PerezHilton.com, it would have been their most viral story of the year. Hell, the decade.
What Quantum claims to have discovered is the (room-temperature) superconductor, something that would theoretically allow extremely fast charging, greatly enhanced energy efficiency, and enhanced battery life for all electric vehicles. In simple terms, the superconductor is the Holy Grail — that which supposedly heals all wounds, delivers eternal youth, and generates everlasting happiness — of all electrical engineering. To fully understand the implications of such a monumental claim, Motor Mouth will (try to) walk you through how a superconductor works, what its implications for the future are, and why we don’t already have them.
What is a superconductor?
The name should be fairly self-explanatory, but the term is generally applied to any material that can, well, conduct electricity more efficiently. In actuality, superconductors might be better labelled “perfect conductors” because the reason they cause such excitement amongst the pocket-protector set is that they generate no resistance to the flow of electrical energy. They represent, in effect, the perfect transmission of energy to any device, at any voltage, over any distance, with absolutely no energy lost in the powering of said device. Like I said, Holy Grail.
Why don’t we already have them?
Actually, we do. The only problem is, they are lab rats. As in, while we humans have actually formulated the perfect conductor, the technology itself – like, say, nuclear fusion – only works under the most particular of laboratory conditions. For super-conductivity, those lab conditions are cold temperatures. Extremely cold temperatures.
How cold, you ask? Well, mercury becomes a superconductor at -269C, which, if you remember your high-school physics, is about four degrees from absolute zero, the absolutely coldest temperature possible and attainable only via the use of liquid helium. More recent research has postulated that something a little less extreme on the temperature scale might be possible, but so far, the best anyone could promise was “only” requiring liquid-nitrogen cooling.
Which is why if, like me, the news that LK-99 — named after its two lead researchers, Sukbae Lee and Ji-Hoon Kim — could actually super-conduct at good, old everyday room temperature is nothing short of biblical. And, in fact, that it could do so to above 120C just made it that much more practical. Throw in the fact LK-99 can be built from common everyday materials — copper, lead, phosphorus, and oxygen — and then constructed via relatively simple solid-state synthesis — i.e. baking — for truly Earth-shattering news. I hate to keep using the Holy Grail metaphor, but it is, quite literally, the only applicable metaphor.
How will they make electric vehicles better?
Well, as you can imagine, electric motors built using LK-99 would become more efficient thanks to less (no?) resistance, which would in turn make electric vehicles more efficient. That said, as EV proponents never let us forget, the electric motor is already decidedly more efficient than an ICE engine, so these improvements would be probably be the least of an EV’s superconductor benefits.
Batteries, on the other hand, will gain far more from the implementation of super-conducting materials. Heat, as I think everyone knows, is the enemy of battery efficiency and long life. Less well-known is that much of the heat generated by batteries is the simple by-product of the resistance to the current flowing through wires (the equivalent of heat lost in ICE combustion, if you will). The more resistance, the more heat generated.
Estimates vary, but roughly 50 per cent of the heat generated by batteries is from the resistance to current — called Joule’s first law of heating, after James Prescott Joule, whose investigations of electricity were originally directed at finding a more efficient energy supply for the family brewery — with the rest lost through either cathode reactions or something called entropic heat generation.
Whatever the exact proportion, cooling is probably the most important research currently being conducted in the battery technology field. Whether it’s to cool the sides of the cells, their ends, or both, is a major headache for battery manufacturers. Even the development of new battery chemistries will be affected. Greater energy density — that which will get us more range out of the same-sized battery — usually results in greater heat production, which requires more cooling, which, well—it gets complicated. Reducing the resistive portion of a battery’s heat generation would go a long way in simplifying the transition to battery-powered vehicles.
But even that isn’t the most important benefit.
How do they make for incredibly fast charging?
If the performance of a battery would be greatly improved by the development of superconductors, the act of recharging batteries could undergo a paradigm change. If not quite the two-minute refill of gas-powered ICEs, then at least the much-fabled five minutes we’ve all been promised might be finally attainable.
Heat is, in fact, by far the greatest impediment to fast-charging. With apologies for the return to the torture of high-school physics, that’s because heat generated in a wire goes up with the square of current, via the formula P=I2R. In other words, double the number of amps you put through a wire, and you generate four times the amount of heat. Double it again, you have 16 times the feverishness.
The heat generated while charging is sufficient that most DC fast-chargers have liquid-cooled cables. Yes, the cable you plug into your Tesla for rapid-charging actually has a dielectric glycol — think automobile radiator fluid, here — running through it, lest it a) overheat; and/or b) burn your hand. Even its handle may be liquid-cooled. Roughly speaking, anything pumping more than 200 amps is going to require cooling, and the most I have heard of being transmitted in a cable is the close-to-700-amps Tesla’s V3 Superchargers seem to be capable of.
This resistant to amperage is debilitating. It is why, for instance, many manufacturers have moved to 800-volt systems over previous 400V architectures. Apologies for getting technical again, but doubling the voltage means you can get the same power from half the current which, if you remember my previous nerdiness, means that four times less heat will be generated.
If not quite the two-minute refill of gas-powered ICEs, then at least the much-fabled five minutes we’ve all been promised might be finally attainable
The heat those cables are subjected to may even account for the greater reliability of Tesla chargers compared with the reliability of independent stations (and hence why everybody is signing up to charge with Lord Elon). Many of the problems that cause unreliable charging stations, say experts, is the fragility of their cables — the immense heat generated actually causes them to eventually wear out — compared with their Supercharger counterparts.
Even a simple thing as the length of the cable — resistance increases the longer the path — is part of the equation. One of the reasons that Superchargers can simultaneously carry more current and be more reliable is that they are shorter and less resistive. Yes, packaging even affects the speed and reliability of your charging experience.
Add it all up, and the superconductor-as-Holy-Grail metaphor is not at all over-hyped. Put simply, a reliable room-temperature superconductor could well make battery power the only mobility technology needed. The “fueling” advantage — if not quite the range — advantage of ICEs would be greatly diminished. Hydrogen, whose main advantage for mobility is quicker charging, would prove unnecessary. The advantage of perfect conduction might, in fact, make even long-haul battery-powered trucking viable (though I suspect that jumbo-jetting will still require a liquid fuel like hydrogen). A superconductive material would go a long way in curing the ills of EVs, except that many are wondering…
What if it’s all a hoax?
Since the bombshell news was released a week ago, laboratories around the world have been trying to replicate Quantum Energy’s results — the material’s simple construction would seemingly have allowed for quick rebuttals, after all. The vast majority — at least the vast majority of reputable labs — have since discounted the South Korean claims. It may be that LK-99 is nothing more than a novel magnet — one of the tests, the Meissner, for superconducting is the ability to levitate when subjected to a magnetism, which Quantum’s material in fact does.
Putting aside whether the tests were fraudulent — and what possible motive the researchers would have for such obvious subterfuge — there’s no question that last week’s announcement got the research world in something of a tizzy. On the one hand, there’s the promise out there of a totally practical electric vehicle. On the other, there’s the seeming impossibility of the quest.
Whichever this turns out to be, I have to admit that just the mere mention of a practical superconductor got me a lot more excited than Taylor Swift tickets going on sale. Call me a geek.
Author’s note: This explanation of superconductors and related subjects is the simplest possible, considering that it may be the most complicated subject in engineering. Or at least the engineering I studied. Any omissions are the responsibility of the author, who welcomes any corrections or enhancements.
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