115 ated ranges, these achieve a pleasant climate in the passenger compartment within an ex- tremely short time, even at low outside tem- peratures. The High-Voltage Coolant Heater BorgWarner’s HVCH is available in power vari- ants from 3 to 10 kW and replaces the internal combustion engine as a source of heat for bat- tery and cabin heat management systems in electric cars. By assisting battery conditioning, it improves the service life and increases the range of the vehicle. In addition, the low ther- mal mass of this innovative technology allows rapid reaction times for heating up and cooling down, leading to a permanent homogenous temperature distribution between the battery packs and cells. Durable Thick Film Heating Elements (TFE) (Fig. 1) are at the heart of the HVCH – here a stainless steel substrate carries the dielectric layers and the heating resistors. The technol- ogy, which BorgWarner offers in “single- plate” and “dual-plate” versions, also allows integrated hot plate temperature measure- ment (Fig. 2). Both versions are integrated into a robust aluminum die-cast housing and display a high power density at the TFE. In addition, the design has a high resistance to thermal shock as well as vibrations, oscilla- tions and mechanical stresses. The crucial ad- vantage of the compact “dual-plate” system is that it has two hot plates allowing it to offer up to 80 percent more heat transfer area. Moreover, the heating packages are covered with coolant and only cause minimum heat losses – leading to a higher efficiency – and the three-part aluminum housing provides ex- cellent electromagnetic shielding. BorgWarner has also developed a safety strat- egy for its intelligent solution and its robust power electronics which ensures the preven- BorgWarner www.borgwarner.com Website tion of thermal events such as overheating. As soon as the system detects an error, it switches off automatically. The High-and Low-Voltage Air Heater BorgWarner offers the Air Heater with its weight of 3.24 kg as an easy-to-integrate “plug & play” modular solution and uses it in hybrid and electric vehicles with up to 450 V. By rapidly heating up the air flow coming from the fan, the device with its power of up to 7 kW provides the required temperatures in an ex- tremely short time. Thanks to its low weight and its compact de- sign, the Air Heater is the ideal solution for modern lightweight construction concepts. In addition, the completely enclosed heating el- ement provides maximum protection against high voltages. In conjunction with the fin de- sign of the Air Heater, the heating element en- sures low pressure losses of less than 37 Pa (at 400 m 3 /h), and this in turn allows the fan to work at lower speeds and reduces the noise level in the passenger compartment. The two-zone functionality (Fig. 3) of the Air Heater allows the precise individual regulation of the air flow for driver and passengers – the heat distribution is controlled depending on the demand, and energy losses are avoided. The Air Heater has Protection Class IP67 and is controlled via a high-power CAN (Controller Area Network) bus. PTC components (temperature-sensitive non- linear resistors with a positive temperature coefficient) are the technological components at the heart of the Air Heater. Whereas they operate reliably, provide high heating power, display a low electrical resistance and allow a high electricity flow at low surface tempera- tures, the effect is reversed as temperatures increase. The electricity flow is then reduced by the rising resistance of the ceramic stones and the system releases less heat – in other words, it regulates itself and prevents over- heating. Conclusion When the usable exhaust heat of the internal combustion engine is limited or missing com- pletely, it is a challenge to heat up the passen- ger compartment. As a result of the progres- sive electrification of the powertrain, electric heaters will soon be indispensable. With its ad- vanced high-voltage auxiliary heater systems, BorgWarner not only offers vehicle manufac- turers around the globe an intelligent solution for higher battery-operated ranges, but also a safe air-conditioned passenger compartment in hybrid and electric vehicles which is com- fortable at all times. Fig. 3: The two-zone functionality of the Air Heater allows precise and uniform temperature delivery for the driver and passenger area – with no transfer of heat between the two zones. Fig. 2: BorgWarner offers its HVCH in two versions: the “single- plate” version (right) and the “dual-plate” version (left).