Video: Tesla’s New Liquid-Cooled Superchargers Pave the Way to Even Faster Charging

With the capability to add 170 miles of range in just 30 minutes to Tesla Motors’ flagship Tesla Model S luxury sedan. Tesla’s proprietary Supercharger rapid charging stations are the most powerful electric car charging stations in the world.

Tesla's superchargers are already impressive, but next-gen units now include liquid cooling too.

Tesla’s superchargers are already impressive, but next-gen units now include liquid cooling too.

Unlike other designs of rapid charging stations, which tend to house the heavy power electronics needed to turn high-voltage three-phase AC electricity into the direct current power needed to charge an electric car battery pack, Tesla’s Supercharger design houses its power electronics away from the actual charging stalls. This results in a smaller, more ascetically pleasing charging station that is connected to Tesla’s modular Supercharger units by a long, heavy cable which passes to the charging stall and then on to Tesla’s hidden Supercharge electronic units, often hidden to one side behind a wooden fence.

As any electronics engineer will tell you, the cable is the bulky thickness it is in order to allow 120 kilowatts of high-current electricity to pass along it without causing the cable to heat up and start a fire, with the cross-sectional area of the cable, the length of the cable, and the material it is made from dictating how much electricity can safely pass down it without major system losses.

But as Tesla CEO Elon Musk divulged during last week’s Tesla Motors Annual Shareholder meeting, Tesla engineers have found a way to make Tesla Supercharger cables lighter, more efficient, and easier to use: liquid cooling.

What’s more, thanks to YouTube Tesla Model S vlogger Christopher Allessi II — aka KmanAuto (via GreenCarReports) we’ve got a video of one of Tesla’s first liquid cooled superchargers in action, detailing how cool the cable remains in operation.

So how does Tesla’s new lighter, thinner liquid cable work? To explain, we’ll need to delve into a little physics.

Unlike these units, the next-gem Tesla Superchargers use lighter, liquid-cooled cables.

Unlike these units on the New Jersey Turnpike, the next-gen Tesla Superchargers use lighter, liquid-cooled cables.

While all metals are capable of conducting electricity to some degree or other, every metal has some degree of electrical resistance, meaning that the conductor has some opposition to the passage of electric current through it. For electric wiring, high-conductivity metals such as copper and aluminium are preferred, allowing an electric current to pass along as unimpeded as possible.

That opposition to current flow — or a wire’s resistance —  is dependent on what it’s made of, it’s length, cross-sectional area, temperature and the current being pushed through it.

Increasing a cable’s length, and the current flowing through it, and more of the electrons passing through it will collide with the atoms inside the cable, reducing its efficiency and turning some of the electrical energy into heat energy — which warms up the cable. Thanks to the wonders of particle physics, when atoms warm up, they gain more energy, meaning they move around more in the metal and increase the probability of so-called ‘collisional process’ within the wire. Which in turn raises the resistance of the cable further, reducing its efficiency even more and of course, leads to more energy being converted to heat.

The new design could pave the way for higher-current charging, reducing charge times further.

The new design could pave the way for higher-current charging, reducing charge times further.

(For those who are curious, that’s essentially what happens when you blow a fuse in an electrical circuit, but the wire inside the fuse is designed to quickly burn, breaking the electrical connection, if the current drain is too high.)

Here comes the clever part. To reduce the resistance of a cable for a given current, you can either increase the cable’s cross-sectional area, or reduce its temperature. A super-cooled cable is capable of carrying a much higher current than the same cable in a warm climate, so by cooling the cable along which the electricity passes, Tesla engineers have been able to improve the design of the Supercharger stall cables, replacing the bulky, stiff, unwieldy cables of early superchargers with a more flexible, smaller, liquid-cooled cable.

Just like liquid cooling of the power electronics inside each Tesla Model S, the liquid cooling system allows the supercharger stations to be more efficient, more compact, and capable of operating at full power across a far larger temperature range.

As the video above shows, water-cooled supercharger stalls are slightly different in their design to Tesla’s first-generation Supercharger stalls. First of all, there’s a small vent at the bottom of each stall where the cooling radiators sit. Next, the cable is thiner and lighter, with the actual charge plug replacing the mechanical switch of the original Supercharge connector with a capacitive tough-sensitive one, presumably to increase the area inside the connector for liquid cooling.

Taking an infra-red thermometer to the cabling, Christopher shows that the liquid-cooled cabling is also far cooler on its exterior than previous supercharger cabling, which results in it being more pleasant to handle, especially on a hot summer day.

It’s worth noting too that the cooling system used on this next-generation of Tesla Superchargers also opens up the possibility that Tesla may one day be able to increase the current and therefore the speed of supercharging its cars, especially if the cooling system can lower the temperature significantly enough to allow a higher charge current without sacrificing the smaller, more manageable cabling.

We can’t wait to see what innovation comes next.


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  • vdiv

    The older units shown are not on the New Jersey Turnpike, they are at the Delaware Welcome Center in Newark, DE 🙂

    • Whoops! Thanks. I had forgotten where I’d taken them! 😉

      • vdiv

        Same highway really (I-95). Also they are rarely found that empty anymore. Ah the good old days 😉

        • Dennis Pascual

          I was lucky the few times I used those chargers. At most it was just one other Model S and me.

  • Farmer_Dave

    Did you mean a capacitive TOUCH-sensitive connector switch?

  • Pingback: Tesla’s Liquid-Cooled Cables Could Lead To Faster Charging At Supercharger Stations - All Car News Australia()

  • This is awesome, so many innovations- thank you for making and sharing this- how did Christopher do the thermal imaging like that so nicely in the video? Cheers.

  • dogphlap dogphlap

    Those two air grills are I assume, an inlet and and outlet. If that is true the inlet is far too low. Even if it does not get blocked with leaves (which I bet it will) the amount of dirt that will end up coating the heat exchanger will be much greater than if if were even a foot (30cm) higher and a couple of inches of flood water would be extra bad. It may not look so nice but that inlet (if that is what it is) needs to be moved to a higher position.

  • Dennis Pascual

    Just charged at Mountain View and they are faster than the others and on a Thursday night (last night) it was also half full most of the time I spent there Range Charging.

    There is also a stall 3A that is handicapped preferred (signage explicity asks Model S users to use the stall last, unless they’re handicapped. Last night, on the drive back to LA from the Bay Area, I I took pictures with a Quarter on the cable comparing the width of the new ones with the older ones. I’ll post to flickr.

  • just someone old

    now the weakest link becomes the cables connecting the plug to the battery inside the car
    the supercharger may be able to charge much faster now, but if the cable inside the car overheats, charging will slow down
    will/has the cable between the plug and the car’s battery also liquid cooling? Maybe an unnoticed upgrade of the car?
    Things can go indeed much faster then!!!!!!!

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