With the popularity of many electric cars, more and more people are replacing their traditional cars with electric cars.
Conventional car can use the thermal energy by the engine work to provide heat to the cab when the temperature is low in winter.
And the electric car’s electric motor cannot produce enough thermal energy to heat the cab.
Also, in winter, the battery chemistry is not active and the battery power cannot be fully utilized because of the low temperature. electric car owners also need to heat the battery to raise its temperature in order to make full use of the battery’s electrical power.
According to these factors above, electric cars will need thermal management system more. And electric car heater is one of the very important parts of electric cars.
As an electric car manufacturer, you will know that the thermal management of electric car is much more complex than that of conventional car.
As you read this article, I believe you will have a general understanding of the thermal management system for electric vehicles.
If you are a new electric vehicle manufacturer, you will have an understanding of the thermal management systems available in the market for electric vehicles.
The knowledge in this article will provide some help to your company in choosing the right EV heater manufacturer.
Now, let’s get started.
What is thermal management for automobiles?
First, let’s understand what thermal management.
Thermal management refers to the dynamic heat management inside the car, to make the temperature inside the cabin rise in winter and to make the temperature inside the cabin decrease in summer.
Thermal management effectively manages the heat of the entire vehicle, including the heating and cooling of the engine, battery, electric motor and electronic control parts as well as the passenger compartment.
Heat map of conventional cars
For fuel vehicles, the heating system can effectively reduce engine wear and tear and increase the driving experience of the driver and the ride of the passengers.
For electric vehicles, the ev heating systems can effectively extend the winter range and passenger experience of electric vehicles.
This article focuses on the thermal management of electric vehicles, which is mainly for the temperature management of the battery and passenger cabin.
Types of electric car heaters
From the difference of heating medium, electric car heater can be divided into air heater and water heater.
Electric space heaters is a kind of heater that heats the cockpit of electric car. Its main function is to provide heat to the cockpit of electric car, so that the cockpit is at the right temperature and the driver and passengers can fully enjoy the comfort brought by the electric car.
The electric car water heater mainly heats the air conditioning system of the electric car. In summer when the temperature is high, the air conditioning system will lower the temperature of the cockpit and the battery pack.
EV PTC Heater
In winter when the temperature is low, the heater can provide heat for the cockpit and battery pack through the air conditioning system to keep the cockpit and battery pack at the right temperature.
Depending on the technology, electric car heaters can be divided into roughly six types of heating technology
Before we begin, let’s look at the characteristics of each technology
|Comparison Items||Electric heating technology||Diesel heating technology||Heat pump technology||Battery self-heating technology||Waste heat utilization technology||Phase change energy storage technology|
|Impact on battery range||Big||Little||Little||Medium||Little||Little|
Comparison of six heating technologies
Next, let’s learn more about the characteristics of each heating technology
Electric Vehicle Electric Heating Technology
Electric vehicle electric heaters mainly use PTC heating elements and thick film heating elements (TFE).
PTC electric heater
EV Coolant PTC Heater
PTC electric heater is a kind of heater using PTC thermistor element as the heating element, the resistance of PTC heating element will change with the temperature. Usually, the higher the temperature, the higher the resistance of the PTC.
PTC heaters are the choice of most electric vehicles today.
Depending on how the PTC heater is heated, there are two types of PTC heaters, one that warm air directly and another that heats the circulation system of the electric vehicle.
Here we look at the characteristics of these two heating methods.
|PTC Air Heater||PTC Coolant Heater|
|Advantages||Inexpensive||High heater output power|
|Easy cockpit temperature control||Simultaneous heating of the battery and cockpit|
|High voltage power supply, high efficiency|
|Disadvantages||Low heater output power||Expensive|
|Heated cockpit only||No precise control of cockpit heat|
|Low voltage power supply|
PTC air heater mainly cabin heating and defogs the front windshield of electric cars in winter. However, the popularity of PTC air heaters in electric cars is not very high.
PTC convection air heater is very suitable for use in electric buses. The PTC air heater used in electric buses uses convection heating, it can use DC 450V-700V voltage, and the maximum heating power of the heater is 5000-8000W.
PTC heater working diagram
The PTC liquid heater is the most widely used EV heater for electric cars at present. It can provide heating for the battery in the cold season and also provide heat for the cabin.
Thick film heating element (TFE)
Thick film heating element (TFE)
The thick film heating element is mainly a liquid heater, which heats the battery circulation system of electric cars.
Thick film heating element is capable of generating large amount of heat quickly, and at the same time, the power loss of thick film heating element is very small because there is little direct thermal resistance between heating element and coolant.
At the same time, thick film heating elements are compact and can be designed in a variety of different sizes and shapes.
The EV heater made of thick film heating element has the advantages of high power, small size and light weight. It is encapsulated in an aluminum housing with good electromagnetic shielding and will not cause electrical interference to the vehicle’s.
Diesel heaters can also be divided into two types: diesel air heaters and diesel coolant heaters. They correspond, respectively, to heating the air in the cabin and the coolant in the air conditioning system of the electric vehicle.
Diesel heaters are usually suitable for cold high latitudes because the temperature is particularly low and the battery chemistry will be greatly reduced during winter, which will result in the actual utilization of battery power being only about 50% of the normal temperature. This can reduce the range of an electric vehicle significantly.
The diesel heater, on the other hand, uses diesel fuel as fuel, which, when burned, generates heat to provide heat for the electric vehicle cabin and battery. And the power consumption of the diesel heater is only 30W, which is negligible for the electric car.
Because there is no fuel source on the electric vehicle, an additional fuel tank is needed for the electric vehicle to use the diesel heater. The fuel tank and the diesel heater form a separate heating system.
Diesel heaters are ideal for small electric vehicle manufacturers to choose. Small electric vehicles can be designed with enough space reserved for the heater and the fuel tank. And do a good job of sound insulation. During the use of the vehicle, the noise of the heater working will hardly affect the experience of the driver and passengers.
Contact us for more information. We can also provide customized services for your company.
Heat pump heating technology
Heat pump heating technology is already a very mature technology. It is used extensively in many places.
It works on the principle that the heat pumps system takes the outside heat and transfers it through the system to the interior of the vehicle. It can also transfer the hot air from the cabin to the outside of the cabin in summer, through the heat pump technology, to keep the cabin and battery at the right temperature.
Principle of heat pump type air conditioning system for electric vehicles
The application of heat pumps technology in electric vehicles is still in the initial stage, only a small number of electric vehicle manufacturers, such as Tesla, use heat pump technology in their production of electric cars.
Electric vehicle battery self-heating technology is mainly to let the battery return to normal temperature in low temperatures in winter.
Battery self-heating technology works by relying on the internal discharge of the battery to generate heat before the electric vehicle begins, allowing the battery temperature to rise to a normal temperature that allows the battery to release more power.
Battery self-heating technology is only a supplemental technology and, while the battery is releasing heat, it also loses battery power. Usually, electric vehicle manufacturing companies rarely use battery self-heating technology.
Waste Heat Utilization Technology
Waste heat utilization is also a type of auxiliary heating. It works on the principle that the heat generated by the electric vehicle motor drive, or the heat generated by the high power electronic components working, is collected by the electric vehicle’s equipment and passed through the battery cooling system or directly into the compartment and battery to supplement the heat of the compartment and battery.
The waste heat utilization technology should be used in combination with PTC heaters or thick film heaters to allow the PTC heaters or thick film heaters to save fuel.
It works similar to the heat pump technology, however, the efficiency is lower than the heat pump technology. Therefore, the waste heat utilization technology is slowly replaced by the heat pump technology.
Phase change energy storage technology
Phase change technology uses phase change materials to collect heat and then uses the phase change materials to release heat to heat the electric vehicle.
It works on the principle that the electric vehicle will generate heat from the electric motor or high power electronic components during the driving process, and the phase change material will absorb the heat generated by the electric motor and high power electronic components and store it in the phase change material.
The heat is then released to the interior of the vehicle as needed.
From the above six technologies can be seen, the real value of the use of electric heating technology, diesel heating technology and heat pump technology. These three technologies can effectively convert electrical or chemical energy into heat energy.
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