Thermal And Thermo-Mechanical Modelling of Polymer Overmoulded Electronics

This paper reports on the results from a research project investigating a novel technology for the manufacture of recyclable polymeric modules with embedded electronic controls and power distribution. The aim of this project is to develop a technology that fully encapsulates electronics for use in the demanding automotive environment. A two shot moulding technology will protect delicate electronic circuitry mounted outside of the passenger compartment from extremes of temperature, vibration and humidity. The resultant assemblies will also be readily recyclable, making it possible to cost-effectively separate electronic components from the polymer at the end of vehicle life, allowing the recovery of high purity recyclate. The encapsulating polymers will have low thermal conductivity, so the process of encapsulation will introduce a thermally insulating barrier around the electronics, which will impact on the dissipation of heat from the components. In addition, the thermal performance of the assembly will be further affected by the high temperature environments within which some of these electronic modules will have to operate, such as under the bonnet of a vehicle. This paper will present the results of preliminary models developed for investigating the thermal and mechanical issues arising during the operation of such encapsulated electronics. Analytical models and finite element techniques have been employed to simulate the thermo-mechanical behaviour of overmoulded printed circuit boards. 2