Mechanism of Thermal Stress Relaxation of Non-bonded Al/Graphite laminated Roll Composite

Miniaturization and high-density packaging of power modules for use in vehicles increases the amount of heat they generate. To prevent damage from heat in such packages, we designed, optimized, and fabricated a composite roll laminated with a non-bonded graphite sheet and Al foil. To find the optimal design of this material, we used finite element analysis to model a non-bonded Al/graphite laminated roll composite, using this simulation to assess how the geometry of its constituent materials influenced its thermal stress. Based on this work, we found that the larger the aspect ratio of the Al foil, the greater the deformability of the composite and the higher its stress relaxation effect. In addition, we found that sandwiching the graphite sheet between the Al foil deforms the foil into a convex shape, and that the Al/graphite laminate composite shows higher thermal stress relaxation than the Al foil does on its own.