A ROBUST ANALYTIC MODEL OF FOLDED FIN COLD PLATES FOR AUTOMOTIVE POWER ELECTRONICS COOLING
The development of high power density automotive power electronics led to newer, and often more costly, cooling
solutions in pursuit of maintaining desirable operating temperatures. This has been followed by a shift of focus
from proving new technologies to producing low-cost electric and hybrid-electric vehicles accessible to more customers, resulting in renewed interest in low-cost solutions to power electronics cooling. Folded fins are one such solution, common on mass produced heat exchangers, and have been applied in legacy power electronics cooling systems. This paper presents an analytic model that allows for an expedient, robust, and accurate thermal analysis of a folded fin cold plate. The model combines empirical and algebraic approaches to capture heat transfer effects in a 3-dimensional, multi-phase domain including the transistor, cold plate, and coolant. In practice,
computational analysis is often used in place of empirical and mathematical methods. The methods described here have the advantages of allowing for broader and more efficient trade studies due to vastly shorter solution times and providing junction temperature estimates within 5 °C of computational methods, and therefore complement
computational methods. Lastly, use of the model to design a cold plate for an insulated-gate bipolar transistor cooling system in a hybrid electric vehicle is described. The model is used to explore manufacturability constraints, fouling criteria, assembly methods, fin types, and materials of construction. The result is a design that provides a comparable operating junction temperature in the IGBTs with a significant cost reduction compared to a more exotic legacy design.