Lid cooling for notebooks

In this paper, we investigate the effective use of the notebook lid area for passive heat dissipation. We address the hinge design challenges associated with this and propose different spreader options for increasing the overall effectiveness of this solution. For transferring the heat to the lid, we have designed and developed a novel thermo-mechanical hybrid hinge that can provide the required torque and simultaneously conduct the heat from the component in the base to the lid. The mechanical and thermal performances and its reliability were evaluated under an accelerated degradation testing environment over a period of 22,000 cycles. The performance degradation observed was within the experimental error of 5%. While a standard Aluminium spreader does increase overall passive dissipation, it was found that this could be further increased by 80% through the use of advanced graphite spreaders. As a second low cost alternative, we also found that an aluminium spreader with 3 flattened heat pipes (1 mm thick) attached to its surface increased cooling by 40% as compared to an Aluminium spreader. Final experiments on a notebook by use of the hybrid hinge and an advanced graphite spreader based lid cooling solution demonstrated a 60% increase in passive dissipation over a regular notebook without lid cooling.