The Function of PTC Heaters
The heating and air conditioning in fuel-powered vehicles use waste heat from the engine. However, pure electric vehicles lack an engine, so preheating is not necessary; therefore, they require additional heat generation. PTC heaters are currently one of the most mainstream and technologically mature solutions.
PTC heaters have two functions:
1. Cabin heating: Providing warm air to the passenger compartment.
2. Battery pack heating: In low-temperature environments, they heat the power battery to quickly reach its optimal operating temperature (typically 10°C-30°C) to ensure charging efficiency, discharge power, and battery life.
There are two common types of PTC heaters: PTC air heaters and PTC water heaters(as shown in the figure below).
How PTC Heaters Work
1. How Air-Heated PTC Heaters Work:
When the driver turns on the heater and sets the temperature, the battery powers the PTC heater. The PTC heater rapidly heats up. The blower then blows cold air over the hot PTC heater, heating the air and delivering it to the cabin through the air duct, achieving the desired heating effect.
2. Working Principle of a Water-Heated PTC:
A PTC water-heating module is immersed in a box filled with coolant. When high voltage is applied, the PTC heater first heats the coolant. An electric water pump then pumps the hot coolant into a heater core (similar to the heater tank in a fuel-powered vehicle) or into the liquid cooling plate inside the battery pack, heating the cabin air.
This method is more complex, but it provides more even heat distribution and is particularly suitable for battery packs requiring high temperature consistency.
Many modern electric vehicles are equipped with both air-heating PTCs (for quickly raising the cabin temperature) and water-heating PTCs (for battery thermal management and maintaining a constant temperature).
