印刷电路板散热过孔导热率计算方法及优化

为了对电源设备的印刷电路板(PCB)散热过孔的导热性能做优化提高,推导了一套理论计算公式,采用数值仿真、实验测试的方法验证了该公式的可靠性。通过该理论计算公式,研究了散热过孔的孔径、填充的材料以及过孔镀铜厚度对导热率的影响。研究结果显示,过孔内孔直径为0.45 mm为最优直径;填充材料为FR4或者Rogers时没有明显的改善,但是如果用焊锡等高导热率的材质填充时导热率有明显的提高;过孔镀层厚度对导热率的影响非常大,呈线性的增长关系。采用该结果推荐的三种散热过孔优化方案,能使导热率分别提高6.5%,35%及51%。

Calculation and optimization of thermal conductivity of via hole in PCB

to enhance the thermal conductivity of via hole in PCB of electrical power units, a formula was deduced to calculate the thermal conductivity of via hole. This formula was verified by both numerical simulation and experiment. With the formula, the impacts of via hole diameter, filling material and copper plating thickness on thermal conductivity are studied in this paper. The conclusions are that via hole diameter of 0.45 mm is the best value; FR4 or Rogers; filling material of the via hole can get minor benefit on thermal conductivity, but if filling with high conductivity material such as solder, the thermal conductivity is improved obviously; the plating layer thickness of via hole impacts the thermal conductivity most, which appears a liner growth relationship between the thickness and the conductivity. With the three recommend optimization methods, the thermal conductivity of via hole can increase by 6.5%, 35% and 51% respectively.