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缩短寒冷地区质子交换膜燃料电池的启动时间是目前车用氢燃料电池冷启动亟待解决的难题之一。研究通过热传递数据分析,应用COMSOL有限元仿真软件,对比分析2种不同外形尺寸的30 kW氢燃料电池电堆低温保存恒温系统所需的热量,提出一种应对车用氢燃料电池低温存储和冷启动难题的方法。研究结果表明,在-30℃低温环境中,长宽比较小的电池堆维持恒温时更节能,使用33.93 kg纯石蜡的相变潜热,或消耗1.15 L纯甲醇燃料所提供的6 786 kJ能量,即可使氢燃料电池堆维持在0℃以上13 h,为车用氢燃料电池低温存储和冷启动提供了一种新途径。 相似文献
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采用微波辅助化学浴沉积法快速制备了硫化镉薄膜(CdS),并对薄膜进行了X射线衍射(XRD)、紫外透射和吸收光谱的测试和分析.利用测试结果计算CdS薄膜的带隙宽度与以往结果相同.由于传统制备方法中热量从外向内传播,而微波有很强的穿透能力可在很短时间内均匀加热,所以此种方法制得的CdS薄膜质量较好,沉积速度明显提高. 相似文献
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Electrochemical impedance spectroscopy (EIS) is widely used in fuel cell impedance analysis. However, for ohmic resistance (RΩ), EIS has some disadvantages such as long test period and complex data analysis with equivalent circuits. Therefore, the current interruption method is explored to measure the value of RΩ in direct methanol fuel cells (DMFC) at different temperatures and current densities. It is found that RΩ decreases as temperature increase, and decreases initially and then increases as current density increases. These results are consistent with those measured by the EIS technique. In most cases, the ohmic resistances with current interruption (RiR) are larger than those with EIS (REIS), but the difference is small, in the range from –0.848% to 5.337%. The errors of RiR at high current densities are less than those of REIS. Our results show that the RiR data are reliable and easy to obtain in the measurement of ohmic resistance in DMFC. 相似文献