Electric vehicles have heated components that need to be cooled. EVs come with liquid and air-cooled systems, but do they have water pumps as well?
Electric vehicles use multiple water pumps instead of one as a form of liquid cooling. This is because the mechanisms involved in powering an electric vehicle cannot be air-cooled.
Electric vehicles cannot be air-cooled, so they contain two separate water pumps for cooling. Read on to discover the water pumps that come with Electric vehicles and why they need them. We will discuss how water pumps in Electric vehicles work and the differences they have in comparison to regular pumps.
Why Electric Vehicles Need Water Pumps
Electric vehicles require water pumps because, like internal combustion engines found in gasoline-powered vehicles, they have multiple sources that generate a lot of heat. Though the heat produced by an electric vehicle is not as hot as the heat produced by an internal combustion engine, there is still a need to cool EV components with a water pump.
Some components that produce heat in an electric vehicle include:
- Electric Motor(s)
- DC Converter
All of these components require liquid cooling because air cooling could cause an electric vehicle to overheat. Air cooling is done when there is no water pump present in an EV to cool the various components. Though this is rare, there are Electric Vehicles on the market that are air-cooled, mostly in early models like the Nissan Leaf.
Newer electric water pumps can last longer than mechanical water pumps. Mechanical water pumps operate with parts like the serpentine belt that break down more frequently. Electric water pumps typically last between eight and ten years or over one hundred thousand miles. Serpentine belts often need replacing much sooner than that.
How An Electric Vehicle Water Pump Functions
Electric vehicles contain multiple electric water pumps that turn on and off as needed. The ECU, or Electronic Control Unit, a small device in the vehicle responsible for detecting the need for cooling, will turn the electric water pump on when circuits need to be cooled, then back off once they reach an appropriate temperature.
These systems have targeted cooling that helps reduce the load on the battery. Electric water pumps work with an indirect liquid cooling method, meaning the coolant is indirectly cooled by air from the radiator and circulated through the engine. A direct liquid cooling method is being tested, eliminating the need for water pumps in the future.
What is Indirect Liquid Cooling
Indirect Liquid Cooling is the method of cooling used by both Electric Vehicles and Internal Combustion Engine Vehicles. The systems in both options are very similar. A system of pipes that contain the liquid coolant runs through the vehicle. The liquid coolant transfers heat from the battery pack in order to control its temperature.
Indirect cooling systems are designed so that there is no contact between the air and the coolant used in the system. These systems use the water pump to circulate coolant through the pipes. The water then heats up when transferring heat away from the engine. The water is routed through a radiator, where a fan cools it. The water is then circulated back through the pipes, repeating the process.
In these systems, the air is never directly cooling the water; the two are kept separate, never mixing. Though indirect cooling comes with its disadvantages, like possible coolant leaks, there have been several advances in the technology accompanying indirect liquid cooling. Tesla has decreased the size of the piping that normally carries coolant through the engine into much smaller hoses that pose less of a risk for leaking.
What is Direct Liquid Cooling or Immersion Cooling
Direct Liquid Cooling is the method of immersing a battery into a dielectric coolant to keep it at the appropriate temperature. The dielectric coolant is circulated with a pump, similarly to indirect liquid cooling, transferred to a radiator, then back to the battery. One advantage of dielectric coolants is that they are non-toxic and biodegradable. Some dielectric liquid coolants are food-grade, making them more easily disposable than traditional coolants.
This type of cooling is not yet used in electric vehicles but is slated to be the future cooling method for most electric cars. Immersion cooling is being tested in various sectors of the energy industry in data centers and transformers. The environmental impact of a more environmentally friendly coolant is pushing the automotive industry to begin testing this method.
Some advantages of this type of cooling are:
- Opportunity for fast charging in electric vehicles
- Longer battery life
- Optimized heat transfer
- Fire suppression properties
Direct liquid cooling is being tested in the world of electric vehicles and is bound to be the future form of cooling, making water pumps mostly obsolete.
Differences Between EV Water Pumps and Regular Water Pumps
Electric vehicles usually come with multiple electric water pumps that cool the various heat-producing components of the vehicle. The electric water pumps in an EV turn off and on automatically when they are needed. These water pumps are under much less stress than mechanical pumps as they are not run 24/7 and are not used in combination with high-pressure belts.
Some Advantages of an Electric Water Pump include:
- Elimination of a belt, meaning less wasted engine power or electricity.
- No serpentine belt, meaning there are fewer parts to maintain
- Electric water pumps are smaller and save space in the engine compartment
Internal combustion engines typically work with one mechanical water pump that is driven by the serpentine belt and is always on and cooling. These ICEV water pumps work with indirect liquid cooling, just as the electric vehicle water pumps do. The only difference is that they are run constantly and at a high pressure since they are at the mercy of the serpentine belt operated by the engine.
Are There Electric Vehicles Without Water Pumps?
The Nissan Leaf is the one Electric Vehicle notorious for still using air cooling instead of liquid cooling even into 2021. Air-cooled engines rely directly on air circulation over fins or a fan located in the front of the car to keep the components at a proper temperature.
One variable that can cause an air-cooled engine or electrical components to overheat is the outside ambient temperature. On days with extreme heat, air-cooled engines may be prone to overheating because there is no liquid coolant present to transfer heat from the engine or components.
Electric vehicles with air-cooled components that are exposed to extreme temperatures are prone to overheating and severe degradation of the electrical components of the vehicle. Some of these components can completely shut off in extreme temperatures.
As an advantage, air-cooling comes without possible leakage and subsequent electrical shortages. Liquid-cooled EVs can experience leaks in the piping throughout the engine. If liquid gets onto any electrical components, it can cause a shortage in the vehicle and a costly repair for the owner.
Electric vehicles contain water pumps, just like gasoline-powered vehicles. The difference is that Electric vehicles include multiple electric water pumps instead of one mechanically operated pump. These electric water pumps use indirect cooling, just as an internal combustion engine does, to cool the various components under the hood. There are some electric vehicles, like the Nissan Leaf, that do not have water pumps. That vehicle uses an air cooling method that comes with several disadvantages when compared to the traditional liquid cooling method used in modern vehicles.