超薄钛双极板微流道精密成型工艺研究

Research on micro-channel precision forming process of ultra-thin titanium bipolar plates

纯钛薄板因耐蚀性好、密度低和比强度高等特点,被认为是质子交换膜燃料电池双极板的理想材料。通过冲压工艺对厚度为0.1 mm的超薄钛板(纯钛薄板)进行冲压,实现了超薄钛双极板的微流道精密成型。研究了不同冲压载荷、保压时间及各向异性对超薄钛双极板微流道冲压成型的影响,并通过模具加热冲压试验,总结了温度对成型效果的影响规律。研究发现,室温时钛板沿轧制方向(Rolling Direction,RD)、对角线方向(Diagonal Direction,DD)和垂直轧制方向(Tangential Direction,TD)取向所能成型的流道极限深度分别为496.6、521.5和589.6μm;温度的升高会降低钛板的变形抗力,与室温成型相比,高温成型的双极板在流道深度大幅增加的同时流道局部壁厚集中减薄现象也有所改善,提高了双极板的整体成型效果。

Pure titanium thin plate is considered to be an ideal material for Proton Exchange Membrane Fuel Cell(PEMFC)bipolar plates due to its good corrosion resistance,low density and high specific strength.The ultra-thin titanium plate(pure titanium thin plate)with thickness of 0.1 mm was punched by stamping process,and the precision forming of ultra-thin titanium bipolar plate micro-channel was realized.The effects of different stamping loads,holding time and anisotropy on the micro-channel forming of ultra-thin titanium bipolar plate were studied,and the influence of temperature on the forming effect was summarized by stamping test with heating mould.The study found that the limit depth of the flow channel that the titanium plates can be formed along the Rolling Direction(RD),Diagonal Direction(DD)and Tangential Direction(TD)orientations at room temperature is 496.6,521.5 and 589.6μm,respectively,and the deformation resistance of titanium plates can be reduced by the increase of temperature.Compared with forming test at room temperature,the channel depth of bipolar plate formed at high temperature is greatly increased while the phenomenon of concentrated thinning of channel wall thickness is also improved,which improves the overall forming effect of the bipolar plates.