A Multi-Physics Finite Element Analysis of Round Pin High Power Connectors

In the past decade, the general public´s means of transportation has begun to undergo a radical transformation, moving away from only using gasoline and moving toward using a combination of gasoline and electricity. One parameter that shouldn´t stand in the way is the overall reliability of the electric vehicle, which is dependent upon the electric connections between the power source and the motor. Using a multi-physics finite element software package and multiscale predictions of electrical and thermal contact resistance, a model was constructed to predict the behavior of a round pin, high power connector under normal vehicle operating conditions. To test the validity of the model, an experiment was devised to measure connector resistance and temperature. The theoretical and experimental results showed the same trends. The possible influence of fretting was also considered by artificially increasing the contact resistance. The model shows that for increasing current and increasing electrical contact resistance, that current becomes more concentrated along the path it travels through the connector. This constriction of current could lead to much higher surface temperatures than the model currently predicts, resulting in thermally induced softening or distortion in the connector.