Experimental evaluation of thermal conductive materials (resins) for increasing the electric motors continuous performances

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : CLIMAT, ENVIRONNEMENT ET ÉCONOMIE CIRCULAIRE, ÉNERGIES RENOUVELABLES, MOBILITÉ DURABLE et HYDROCARBURES RESPONSABLES.

L’engagement d’IFPEN en faveur d’un mix énergétique durable se traduit par des actions visant :

• à gagner en efficacité énergétique ;
• à réduire les émissions de CO2 et de polluants ;
• à améliorer l’empreinte environnementale de l’industrie et des transports ;

tout en répondant à la demande mondiale en mobilité, en énergie et en produits pour la chimie.

Dans cet objectif, IFPEN développe des solutions permettant, d’une part, d’utiliser des sources d’énergie alternatives et, d’autre part, d’améliorer les technologies existantes liées à l’exploitation des énergies fossiles.

Experimental evaluation of thermal conductive materials (resins) for increasing the electric motors continuous performances 

IFP Energies nouvelles (IFPEN) is a major player in research and training in the fields of energy, transport and the environment. IFPEN focuses its efforts on providing solutions to the societal and industrial challenges of energy and climate, in the service of the ecological transition. Its action in the field of sustainable mobility aims at developing solutions for efficient transport, with low environmental impact and limited cost.

Electric and electrified vehicles seem to be the preferred solution to reduce CO2 emissions related to mobility. Whatever the architecture of the future vehicles propulsion system (fuel cell, hybrid or battery electric), the presence of at least one electric machine on board is certain, and this strategic component relies on numerous constraints (cost, environmental impact, supply resilience, compactness, end-of-life treatment, etc.) to which are added the growing need for continuous performance and performance density.

IFPEN is working on the development of high-efficiency motors with the current objective of reducing the mass of strategic raw materials on the one hand and increasing the continuous performances. The common obstacle to these 2 objectives is the greatly increased thermal load, the resistance of the materials and their characteristics in relation to the efficiency of the complete system. 

To meet this challenge, the solution of replacing air, a low thermal conductor, with thermally conductive resins called “potting” or encapsulation is used in IFPEN high power density electric motors.

Potting is a process in which a low viscosity polyurethane, epoxy or silicone material is poured into a predefined shape to encapsulate a heat source element. In an electrical machine this process is used on the stator, which once encapsulated transfers directly by conduction the heat produced by copper and iron losses to the cooling system.

However, the thermal gain of this solution is complex to quantify by the diversity of the types of products used, their method of implementation, their aging, sensitivity to humidity or even by the geometry imposed by the machine to achieve its function effectively. Moreover, the effects of thermal expansion which causes thermomechanical constraints on the formed resin are also poorly known, which requires implementing clearances during assembly which penalizes the quality of cooling by the absence of contact between the potting and the cold source located in the housing. 

We offer an internship activity with the aim at:

• Defining and implementing resin evaluation methods,
• Characterizing experimentally diverse potting materials,
• Modelling materials (thermal and mechanical) and applying them to the electric motor.
• Defining the methods and potting implementation know-how during the machine design phase

This activity will be supported by a bibliographic synthesis, simulations (Ansys) and the proposal for an experimental protocol to characterize the elements.

Desired candidate profile:

Last year of engineering school or second year of a master's degree with major in thermal and/or mechanical engineering.

• Knowledge of ANSYS Mechanical software exploitation, Fluent is a plus.
• Open-mindedness and proactive in ideas proposal.

Keywords: Thermal engineering, electric motor, finite element calculation
Duration and period of the internship: 6 months between January and December 2024
Internship location: Rueil-Malmaison (near Paris), France