Shell may be known for its petroleum past and present but, it is also putting energy into the electric vehicle space. So to speak.
We already told you about some of its efforts building public and commercial charging infrastructure, its involvement in Formula E, and that it’s developing “E-Fluids.” It’s this last category that we want to talk about today. Turns out, this innocuous-sounding label covers an area that may transform electric vehicles and speed the transition away from burning fossil fuels.
The E-Fluids category covers three separate areas: greases, gearbox/motor fluid, and battery cooling fluids (so-called thermal fluids). To help us understand the role of each of these and how they improve electric vehicles, we spoke with Christopher Dobrowolski, who has the official title of E-Fluids Co-ordinator for Shell Lubricants, who patiently explained the role of each of these products.
Although grease has been around practically forever, there is still room for improvement. The advent of EVs brings some unique challenges and opportunities, particularly when it comes to lubricating bearings.
First up is noise reduction. Where they may have been muffled by the noise and vibration of an internal combustion engine in the past, the sound of wheels spinning on their axles is now something that needs to be taken into consideration. And that’s beside the never-ending struggle to reduce friction and longevity.
The bearing within the electric motor presents its own challenge. Besides its normal duties, this grease also needs to prevent electric current from reaching the surface of the bearing, which would cause it to degrade and fail prematurely. Dobrowolski informs us that this formulation requires dielectric properties to add the needed protection.
The fluid formulated by Shell is for a specific sort of electric drivetrain. You see, some automakers integrate the motor and gearbox into one unit – expect this in most of the next-generation electric vehicles, like the upcoming BMW iX3, for example – while others keep them separated. The more compact, integrated designs share fluid, so not only does the lubricant need to reduce friction and wear on the gears, but it also has a cooling function, flowing inside the motor. This fluid is not to be confused with the liquid – usually a glycol – used in the jacket of the motor specifically for cooling.
Conventional gear oil can still be used in most non-integrated designs just fine. However, Dobrowolski tells us that conventional gear oils do not take into account compatibility properties with the electrical and copper-containing components. Other challenges here include foaming. Some electric motors, like those used in Formula E, can spin over 20,000 RPM.
As a side note, this fluid (as well as that used for battery cooling) is not made from processed crude oil, exactly. According to Dobrowolski, these are gas-to-liquid (GTL) formulations. They use methane, which can come from natural gas or more “renewable” sources like refuse landfills, to create these sophisticated hydrocarbon products.
We’ve saved the (probably) most exciting E-Fluid for last. This GTL product – thermal fluid – may be key to transforming the transportation landscape. But it’s not so much about the substance itself, but rather the battery pack design that it enables. Most battery systems today use a method of indirect cooling – a water/glycol solution is pumped through conduits which run through the pack. This may lead to local hot spots which can speed the aging of cells. Because these coolants are incompatible with the battery cells, they need to be kept separate, hence the conduits.
Now, some pack designers are employing immersion cooling. In these packs, the coolant isn’t contained in tubes. Instead, thermal fluid, which has dielectric properties, is pumped through the pack and reaches every battery cell directly, absorbing their heat. This brings a number of advantages.
It allows for more efficient cooling, enabling up to 350 kW DC fast-charging as well as high, sustained rates of discharge. This is exciting because faster recharging speed is key to electric vehicle adoption. While we may not see 5-minute recharges any time soon, adding 300 miles of range in 10-to-15 minutes is a pretty compelling selling point. And besides the convenience to individual drivers, it also means a single charging station can service more cars in a given period of time, meaning fewer stations would be needed at a location. That’s a win-win for consumers and infrastructure providers.
While more efficient cooling also means less battery degradation and longer life, perhaps the biggest advantage is the space saved. Dobrowolski says battery packs with immersion cooling can be designed with up to 30% higher power density, compared to conventional designs with indirect cooling systems. We imagine that the gravimetric density of the pack (energy stored per unit of weight) could also improve with the removal of interior conduits.
Interestingly, immersion cooling is used in Formula E, where all the packs currently come from a common supplier(s): a partnership between Atieva and McLaren. While you have likely heard of McLaren, the other name is the technology arm for Lucid Motors.
We asked Lucid if this they would be using this battery pack design in its road cars, but they declined to answer. With obvious advantages, and every electric vehicle would-be manufacturer looking for a technological edge to help it stand out from the crowd, we’d be surprised if they weren’t using it.
As we noted at the beginning of this piece, Shell is known for its historical and current fossil fuel business. Petroleum products are still a major part of its portfolio. By leveraging its expertise and moving into E-Fluids and other EV-related areas like charging infrastructure, the company is not only making a space for itself in this blossoming market, but quite possibly speeding up the transition away from fossil fuels in transportation. That strikes us as slightly ironic, but it will be good for all concerned.
As the planet’s climate continues to worsen, profit from petroleum will become more difficult. If the businesses the company develops in this new sector can grow to a significant scale, it might just save itself from its exposure to a dying one.