전기 자동차 배터리 냉각용 알루미늄 평판형 멀티 미니채널 써모사이폰의 열적 특성

Abstract

The design and development of pure and hybrid electric vehicles(PEV, HEV) is becoming a major focus area for the automotive industry due to their high energy efficiency. The effective operation of batteries plays a key role in the overall EV efficiency. Thermosyphon is a kind of heat pipes that transfers heat through convective heat transfer using phase change phenomena of working fluid and, it operates by continuous gravity circulation of the working fluid. It consists of an evaporator section at the bottom of thermosyphon and condenser section at the upper place of thermosyphon. Thermosyphon has main advantage which can manufacture easily because there is no wick structure. The advantage makes it possible to make to various shapes of products. The present research aims at proposing the flat plate multi-mini channel thermosyphon technology as a promising candidate for the thermal management of electronics mounted aboard vehicles. This study evaluated the effect of a various orientation on thermal performance in an flat plate multi-mini channel thermosyphon. A flat plate thermosyphon filled with Novec-7100 (charging ratio 20, 40, 60 voL.%) has been characterized at heat power 6W and 14W. The thermosyphon is an extruded thin aluminum plate of size 170W x 210H x 16T [mm] and had 56 channels. Installation angles of inclination is pitching, rolling, and yawing are used. Results indicate that the thermosyphon operated in the pitching, rolling, and yawing position allow it to reach good performance in terms of start-up heat input, effective thermal conductivity and operation stability. The results were summarized as follow: 1. It is confirmed that it has a constant heat flux for operation. The effect of charging ratio variation showed the best performance at 20%. 2. The thermosyphon with q=450W/m² and q=1000W/m² showed smooth flow behavior with enough cooling performance. At the heat input of 6W and charging ratio is 20%, the temperature source and the sink was 40~45℃. And 14W and charging ratio is 20%, the temperature of heater(battery surface) was 60~65℃. 3. The experimental result according to the pitching inclination angle, the thermosyphon operates at more than 3° and the rolling inclination angle, the thermosyphon operates at more than 30° and the yawing inclination angle, the thermosyphon operates in the whole angles (0 to 90°). 4. In the multi-mini channel thermosyphon, the limiting condition of the inclination angle need to bend the condensation side by 3 to 5° to overcome it.