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Everything You Need to Know About EV Coolant

Here's what you need to know about EV Coolant

Just like ICE vehicles, EVs need to keep their internal systems from overheating. If your electric car’s battery gets too hot, it can overheat and affect the lifespan, and you may have to fork out for a brand-new battery.

Luckily, EVs are fitted with cooling systems to prevent this from happening. There are several ways your electric car may do this, and one of the options is liquid coolant, in the same way you put coolant in an ICE vehicle.

Do EVs Use Coolant?

Yes, EVs use coolant. The difference between ICE and EV coolant is that the battery needs to be kept cool, rather than the engine.

There are several different ways EV’s do this, with the two most popular being liquid and air.

What are the EV Cooling Systems?

Liquid

Liquid cooling works in one of two ways: directly, or indirectly.

Direct cooling is dependent on the coolant being a non-conductive liquid, as it involves submerging the battery into the coolant. It does come with safety concerns, which is why indirect cooling is the more popular option. This works by circulating liquid coolant throughout pipes that run alongside the battery, in a similar way to ICE coolant. This coolant needs to be non-corrosive as well as have a high heat tolerance.

Air

Air cooling works by running cool air along the surface of the battery. This cools the battery down by transferring the heat away from the battery pack.

Other

There have been other methods of cooling used on certain EVs, such as fan cooling, and phase change materials – when a substance absorbs and releases the heat – however they haven’t proved as successful as liquid or air cooling.

This is because they don’t align with the design, or even affect the performance of the vehicle.

This video from The Buzz EV does well to explain EV coolant:

What Type of EV Coolant Does My Electric Vehicle Use?

The majority of EVs use glycol-based coolants. This is because they are not conductive, and therefore work best alongside the lithium-ion battery. Some older models, such as the Nissan Leaf and the Renault Zoe, used air cooling upon their introduction.

It is important to ensure your EV has the correct coolant – using the wrong kind could be catastrophic. If your EV uses a liquid coolant, you’ll be able to find out the exact kind of coolant you need by reading your vehicle ownership manual or speaking to an EV-trained mechanic.

Which is Better – Liquid or Air?

Liquid cooling is an effect way to keep the temperature down inside your EV and keep everything running as it should do.

Air doesn’t have the same cooling power that glycol-based cooling fluids do. Liquid cooling allows for greater amounts of power and reduces the risk of overheating drastically.

Which EV Brands Use Liquid Cooled Batteries?

Tesla

The world’s most famous electric car brand uses liquid cooling, much to the approval of their founder Elon Musk – he even went as far to call Nissan’s air-cooling design ‘primitive’. Tesla have patented their system, named a ‘battery management system’ (BMS), which also helps keep the battery warm when the temperature outside drops.

The Model S uses a pump-based coolant, which uses a water-glycol coolant. Its battery requires an auxiliary water pump which is used to drive the coolant through the circuit. The patented serpentine design allows each battery cell to maintain full contact with the coolant, ensuring effective cooling every time.

BMW

German super brand BMW are investing in research into thermoacoustic, electrochemical, and absorption cooling, but for now, favour the liquid cooling method. The i3 uses AC fluid, which means that the air conditioning compressor is utilised to push the coolant around, rather than a water pump.

This method also means that the battery uses less coolant, however there is additional pressure on the air conditioning system. This means they need to be reinforced to keep up with the demand.

Chevrolet

Chevy have made use of several different systems over the years, from a ‘loop’ like Tesla’s BMS, and a bottom mounted AC system such as BMW’s.

The Chevrolet Bolt uses a bottom cooling plate, which uses a water-glycol mix rather than AC refrigerant. The Volt – the first commercially available plug-in hybrid- paved the way for liquid cooled electric cars, and without it, the market may have looked very different.

Ford

Ford stated in 2010 that they believed that ‘Active liquid systems are more effective than air systems at regulating lithium-ion battery temperature’, and proved this by fitting their first EV, the Ford Focus Electric, with a liquid cooling system.

The Focus is innovative as when connected to the electric grid to charge, the car uses ambient temperature data to adjust the battery, so that it is always charging at the optimal temperature. Many brands now try to make this a standard with EVs.

Jaguar

Jaguar’s I-PACE model has a sophisticated thermal management system which allows the temperature of the battery, the electric motors, and the passenger cabin to all be kept at the perfect temperature. It uses the heat generated by the motor and uses that to warm up a cold battery or the cabin – almost like regenerative braking for your heating system!

This is another innovative way in which electric car brands are repurposing energy otherwise lost, and Jaguar are doing it with liquid coolant.

Do You Need to Change Your EV’s Coolant?

It depends on the individual model of electric car, but the majority of EVs will not require you to change or top up the coolant over the lifespan of your vehicle.

This is because the coolant in your EV will have less exposure to extreme heat, meaning that it’ll last much longer. However, if you choose to change the coolant in your electric vehicle, you can extend your battery’s lifespan and keep it running like new.

We recommend you do not attempt to do this yourself, and instead take your EV to a qualified garage.