Could immersion cooling be the key to superfast charging and a reduction in range anxiety? Mark Lashbrook, technical manager at M&I Materials, gives us his insight.
The electric vehicle (EV) revolution is well underway. In the UK and around Europe, deadlines are being set for last orders on internal combustion engine (ICE) vehicles and companies with various visions are taking early steps in developing both EVs and charging infrastructure.
Yet progress is hampered by the same perennial thorns in the sector’s side, namely: range anxiety and charging speeds.
Some argue that changing behaviour patterns is the solution here, altering our relationship with our cars. Yet, we shouldn’t be too quick to write off an engineering solution.
We think that, as the EV sector hots up, immersion cooling can play a crucial role in reducing range anxiety and increasing charging speeds. Although range anxiety and super-fast charging are two separate challenges, the solution for both could be the same.
Road blocks to EV uptake
Buying a new car is a big purchase, which usually raises a lot of questions. Which brand/model to choose? How many doors? Colour? Now, drivers have the option to have fully electric vehicles, hybrids and plug-in hybrids amongst others.
This increase in choice brings about an increase in questions. How will I charge it? Where will I charge it? How often do I need to charge it? Sixty-four per cent of respondents to a recent JD Power survey are concerned about the availability of charging stations and 59% are concerned about range.
In context, most respondents said they’re only willing to wait 30 minutes to charge their vehicle to travel for 200 miles.
In built up urban areas, lack of off-street parking can make home-charging more of a challenge, leaving potential buyers with no easy answer on where to charge their car.
Some might be able to charge at work. Others will be left thinking they’ll need to charge their car in the same way they currently fill up their ICE vehicles, with a trip to a fuel station.
Here’s where a lack of superfast charging can become an everyday problem rather than a challenge reserved just for motorway journeys.
Right now, you drive up, fill up and leave all within a five to ten-minute window, this same experience needs to be replicated for the EV market. In an ideal world, on your way home in the evening you pull up to a charging station, you plug in, you pop in, you get a coffee, shop for a few minutes, when you come back out the car is charged.
This barrier to entry needs to be removed to ensure electric vehicles are widely adopted, but are also the desired choice well before consumers are unable to purchase ICE vehicles.
But what can be done? Unfortunately, it isn’t as simple as installing more or faster charge points. Batteries are a bit like people, they like to be kept within a small temperature range.
Keeping batteries between 15-35°C keeps them working at optimum performance. When undertaking superfast charging the power flows are greater which increases heat in the batteries. To enable superfast charging, the batteries (and charger) need to be effectively cooled to keep them within the optimal range.
A chemical solution
It isn’t all doom and gloom, however. Engineers have devised a solution to the range anxiety and superfast charging problem – immersion cooling.
Immersion cooling is a method of thermal management that can keep batteries and charge points cool. The former involves batteries being fully submerged in liquid to carry the heat away, whilst the latter comprises liquid flowing from a charge point cable to a connector in a temperature controlled loop. This has already been tried and tested in other sectors, including data centres, subsea cables and transformers.
Immersion cooling was considered an early frontrunner for EVs. However, at this point the composition wasn’t right and the proposed fluid too heavy. Keeping the weight of EVs down is crucial to their success, so alternative cooling methods were pursued.
There are a few ways batteries can be cooled – air cooling, plate cooling and pipe cooling. All come with their different benefits and applications, but none offer the best possible solution for superfast charging.
Air cooling is typically used in more budget ranges of EVs and the vehicles are passively cooled. This can lead to slower charging speeds and more wear on the battery.
Plate and pipe cooling offer a more sophisticated approach of pulling heat away from the battery. Refinements and efficiencies are being made in both of these technologies which is why we can see faster charging and higher power output vehicles, but charging still typically takes between 30 and 40 minutes.
The fastest charge speeds are only available for the first few minutes and quickly have to be reduced to protect the battery cells from overheating. While these technologies can be developed and improved further, a step change in our thinking around cooling might be the key to solving the superfast charging challenge.
That’s why immersion cooling deserves a second look. So, M&I Materials, which has a rich heritage in dielectric fluids, has developed a new chemical formula specifically designed for EV batteries – MIVOLT DF7.
The improvement in cooling technology goes past range anxiety and superfast charging. At the most basic level, a better cooled battery is a better performing battery. This means higher performance, more range on a single charge and a longer cell life, all increasing the value proposition for electric vehicles.
The road ahead
So, where could this technology take us? The use of MIVOLT’s dielectric fluid in charging cables and car batteries will enable a future where the user experience of fuelling cars remains similar to today, but the environmental impact considerably reduced.
This is especially true when it’s considered that MIVOLT is a fully biodegradable and non-toxic fluid that doesn’t hamper the recycling of batteries.
This isn’t the first mobility revolution we have gone through. Previously horses were swapped for cars and the necessary infrastructure delivered – forecourts built, car parks created and mechanics trained. This transition could be less revolutionary.
The forecourts of the future could look very similar to the forecourts of today. Where super-fast charging drivers can pull up, quickly charge where the pumps used to be, and drive off. Existing urban infrastructure can have charge points installed to minimise impact of new infrastructure on the city environment.
Tomorrow’s future could be closer to today than we think.
