The battery of an electric vehicle is the most important part. Lithium-ion batteries are sensitive to extreme temperatures and must be prevented from overheating at all costs. If your EV’s battery dies, you’re basically left with a useless case.
This is why EV manufacturers have developed systems to help monitor the battery and keep it working properly, including proper battery cooling. But how do EV battery cooling systems work and how do they keep your EV’s battery safe?
Why is battery temperature regulation important in an EV?
Lithium-ion batteries, the type of batteries used in most EVs, don’t like high temperatures. Keeping your electric vehicle battery away from extreme heat is one of the best ways to take care of your EV’s battery. These batteries work best at temperatures that are not at the extreme ends of the scale.
This means that the batteries should not drop to freezing temperatures, and care should also be taken not to overheat them. Charging a battery at freezing temperature is not recommended; therefore, some manufacturers offer options to prepare the battery before charging in freezing scenarios.
Icy conditions can damage your EV’s battery, but extreme heat can do the same or worse. If your EV’s battery gets too hot and isn’t cooled enough, especially while charging, the battery may experience a thermal event. If the heat gets too out of hand, it can eventually start a fire.
It’s clear that EV car makers should prioritize proper battery cooling, and they certainly have. Modern EVs are equipped with advanced thermal monitoring and control systems, which monitor the temperature of the battery and ensure that the battery does not get too hot.
If the battery gets too hot while charging, these systems can fine-tune the charging speed. By doing this, overheating of the battery can be prevented.
Some EVs use liquid cooling to regulate battery temperature
There are several ways to keep an EV battery cool, and as with combustion engine vehicles, one of these methods is to use liquid coolant. This method is an alternative to simply cooling the battery with air. Air cooling has been around forever and has become famous in vehicles like the Porsche 911, which used air cooling before the newer generations switched to liquid cooling. Air cooling is a simple system that eliminates leaks, for which liquid cooling systems have a clear predisposition.
But ultimately, liquid cooling systems are better at cooling than air, because liquids have a vastly superior ability to transfer heat. That’s not to say that air cooling is terrible, and some popular EVs, like the Nissan Leaf, use this method successfully. Although, it must be said that it is still preferable to have liquid cooling systems in very hot climates.
EVs that use liquid coolant to cool their batteries have a system similar to that of a traditional ICE car. In an ICE vehicle, the coolant is circulated through the engine through channels made specifically for the coolant. The coolant absorbs heat from the engine and is then transferred to the radiator, where a fan blows air onto it and cools it. This method of cooling vehicles is quite effective and ICE vehicles can use the heat from the engine to warm the cabin.
In the case of liquid-cooled EVs, the battery is the component that needs constant cooling. The cooling system routes coolant around the battery, absorbing heat and then directing it to a radiator. Once the hot coolant reaches the radiator, a fan can help lower the coolant temperature by blowing on the radiator.
These systems, of course, differ slightly from manufacturer to manufacturer, and the cooling channels around the battery can differ between car manufacturers. It is important to note that EVs have less maintenance requirements than ICE vehicles, which is one of the benefits of owning an EV, coolant eventually needs to be maintained.
The coolant prevents corrosion, except for heat transfer, so it is important to keep the coolant fresh to protect the cooling system passageways. Unfortunately, the maintenance of an electric car is still a bit of a taboo. Many think that these vehicles are black boxes that should not be touched unless you are a certified tech from the manufacturer. The truth is that many of the components of an EV are very similar to conventional cars, and maintaining them shouldn’t seem like a mythical undertaking.
Some EVs use air cooling for the battery
Liquid cooling for EV batteries is definitely the more advanced alternative and apparently the more efficient as well. Liquid coolants will always outperform the air in dissipating heat away from the battery. Simply blowing air over a battery will help somewhat with heating problems, but liquid coolants can dissipate much more heat from the battery.
Regardless of the physical side of things, some EVs, like the Nissan Leaf, have decided to embrace air cooling. Air cooling isn’t something you’re likely to see applied to high-power EVs, especially large vehicles over 800 horsepower. But this technology gets the job done in less demanding applications. For example, Nissan has been deprived of liquid cooling for years on the Leaf. In fact, even after its redesign, the Leaf is still a proud air-cooled EV.
Many owners have complained about the Leaf being air-cooled, and it’s possible that the lack of water-cooling could lead to premature battery wear. Anyway, Nissan sticks with this one.
Liquid cooling is the future for EV batteries
EV batteries have very strict thermal requirements and must be kept within a certain temperature range for optimal functionality. Liquid cooling seems to be the most promising technology for keeping the temperature of an EV at bay.