High-voltage positive temperature coefficient (PTC) heaters have a high heating capacity and are fast acting; thus, they function as the actual main heating equipment in electric cars, and considerable research is devoted to improving their heating performance and efficiency. We evaluated the heating performance of a high-voltage PTC heater for an electric car by building a closed-loop-type test system including an air channel, environment chamber, DC power supply, and data acquisition system, and designed an initial prototype with general characteristics. Using this test system, we analyzed the heating performance characteristics of the heater as a function of changes in the blower airflow, ambient temperature, and battery voltage. We changed the geometrical variables of the heater and conducted an analysis to improve the heating performance and output density of the initial prototype. Based on the heating performance of the initial prototype and its geometrical variables, we designed an improved prototype and compared its heating performance and output density with that of the initial prototype. As a result, we achieved a heating capacity of 5.52 kW, a pressure drop of 48.2 Pa, and an efficiency of 98%, whereas the output density was 3.45 kW/kg, which is a 24% improvement over the initial prototype.

Electric vehicles use positive temperature coefficient (PTC) heaters and heat pumps to warm the vehicle cabin. High-capacity PTC heaters are needed because heat pump performance decreases sharply in the winter months due to low outdoor temperatures. The weight of PTC heaters is an important heater design factor for improving the single-charge travel distance of electric vehicles. A fin shape is necessary to improve the heater’s heat transfer performance in comparison to its weight. To develop a 6 kW class high-capacity PTC heater for electric vehicles, this study presents a numerical analysis of heat flow according to a modified louver fin’s geometric shape variables and evaluates heating performance. Based on the geometric shape of an initial plate-shaped fin prototype, a numerical analysis was performed on the width, position, height, and angle to develop a modified louver fin while considering heat transfer performance and ease of manufacturing. An improved prototype was built using the developed modified louver fin, and its heating performance under standard conditions was evaluated. The improved prototype had a heating performance of 6.05 kW, an efficiency of 98.0%, a pressure drop of 18.3 Pa, and a heating density of 3.81 kW/kg. Compared to the initial prototype, its heating performance and heating density were improved by approximately 15.7%.