Ni-YSZ|YSZ|LSM固体氧化物燃料电池性能测试

研究出平板式Ni-YSZ|YSZ|LSM单体电池；设计组装了电池性能测试系统；以H2为燃料，O2为氧化剂气体，在温度为500－900℃时测试了电池开路电压随温度和燃料气体流量变化而变化的对应关系；并分析了变化的原因，同时考察了电流电压特性和电流功率特性，发现电池的输出电流和输出功率随温度的升高而明显提高。     

平板式固体氧化物燃料电池的初步研究

研制出平板式Ni-YSZ|YSZ|LSM单体电池 ,电池以H2 为燃料 ,O2 为氧化剂气体。设计组装了电池性能测试系统 ,在 4 0 0～ 10 0 0℃的温度范围内 ,测试了电池开路电压与温度变化的关系 ,分析了变化的原因 ;考察了单体电池的电流电压特性和电流功率特性 ,计算了电池的效率     

液相进料直接甲醇燃料电池性能的实验研究

利用美国Arbin公司燃料电池测试装置，对液相进料直接甲醇燃料电池的性能进行了实验研究。通过电流．电压曲线，研究了燃料电池工作温度和压力、阴阳极差压、甲醇和氧气流量、甲醇浓度等参数对电池性能的影响。实验结果表明：较高的电池温度可以提高电池的性能；阴阳极差压提高，电池性能降低；在甲醇浓度较低时，燃料电池工作压力、工质流量和浓度的增加均使燃料电池性能有不同程度的提高。图8参7     

Cu(In,Ga)Se2集成电池吸收层的三步共蒸工艺

利用三步共蒸法工艺在10cm×10cm玻璃衬底上生长出电池吸收层CuIn_(0．7)Ga_(0．3)Se_2薄膜。通过XRF和XRD谱,分析了不同预置层(Precursor)(In_(0．7)Ga_(0．3))_2Se_3生长温度下CuIn_(0．7)Ga_(0．3)Se_2薄膜的结构特性。预置层生长温度分别为300、340和400℃时,所制备的集成组件的转换效率对应为4．23%、5．16%和7．03%(测试条件为：AM1．5,1000W/cm~2)。其组件效率的提高,归因于在预置层生长温度为400℃时所制备的CuIn_(0．7)Ga_(0．3)Se_2薄膜具有良好的结构特性和组份均匀性。     

染料敏化太阳电池中电子传输性能

通过检测染料敏化TiO2纳米晶太阳电池中TiO2膜厚度和入射光的强度对电池光电转换性能的影响来研究电池中电子的传输性能。结果表明：TiO2膜厚度和入射光强度对电池性能有很大的影响。当TiO2膜厚度增大时，电池的短路电流(Isc)加大，而填充因子(ff)下降，开路电压(Voc)先上升后下降，电池的单色光光电转化效率(IPCE)增大；当光强度加大时，电池的短路电流和开路电压均增加，但是电池的填充因子降低。并用UV-Vis等手段表征了染料RuL2(SCN)2。     

纳米非晶硅(na-Si:H)P-i-n太阳电池

该文报道了通过适当氢稀释(RH=15)和合适的衬底温度(Ts=170℃)下，用PECVD制备得到的宽带隙氢化纳米非晶硅(na-Si：H)薄膜，并将其用作pin太阳电池的本征层。经过电池结构和工艺条件的优化设计，在p／i，i/n界面插入渐变带隙缓冲层，制备出了glass／ITO／p—a-SiC：H／i—na-Si：H／n—nc-Si：H／Al结构的pin太阳电池。电池初始开路电压(Voc)高达0．94V，同时还能保证0．72的填充因子(FF)。光电转换效率(Eff)达到8．35％(AM1．5，100mW／cm^2)。     

太阳能热气流发电系统的性能分析

基于太阳能热气流发电系统的原理,分析了系统的发电功率和能量转换效率.数学模型的建立考虑了太阳辐射和系统尺寸参数对系统最大输出功率和最大能量转换效率的影响.以西班牙试验电站系统为例进行了数值模拟,数值计算结果与理论分析具有良好的一致性.系统最大输出功率不仅是烟囱高度的函数,同时也与系统其他尺寸和环境参数有关;在太阳辐射强度为1000W/m2条件下,当烟囱高度为300m时,系统的最大能量转换效率达到1%,当烟囱高度为1000m时,系统的最大能量转换效率可超过3%.     

CuPc-G-PAn/Perylenes异质结太阳电池性能研究

对聚苯胺材料进行染料接枝改性,将其用作异质结光伏电池的p型材料,制作出结构为导。电玻璃／酞菁铜接枝聚苯胺（p型）／Pei（n型）／Al）简写为ITO／CuPc-G-PAn(p型）／Pei（n型）／A1)的有机p-n异质结光伏电池。该电池在37．2W／m^2的碘钨灯照射下,开路电压Voc=802mV,短路电流I=41μＡ／cm^2,填充因子FF＝58％,能量转换效率大约为0．51％,它比聚苯胺及Pei肖特基电池大得多。通过测量其电流－电压J－V和电容－电压C－V特性,研究了其光伏效应及电学性能。J－V特性表明,二极管的曲线因子约为6．3,比1大得多;C－V特性表明,在CuPc-G-PAn／Pei界面处的耗尽层约为231nm,从p/n层的光吸收谱可知,光激活层在CuPc-G-PAn／Pei界面处,它们分别与ITO及铝形成欧姆接触,对在暗场及光照下电荷传输机理作了较详细的分析。     

低催化剂载量直接甲醇燃料电池性能实验研究

利用自行设计的直接甲醇燃料电池实验系统研究了电池温度、阴极侧压力、甲醇溶液浓度和流量、氧气流量对低催化剂载量（阳极Pt-Ru载量为0．4mg／cm^2；阴极Pt载量为0．4mg／cm^2）直接甲醇燃料电池性能的影响。重点分析了运行参数对电池内部传质的影响。实验结果表明提高甲醇溶液浓度和流量不仅会强化甲醇向阳极催化剂层的传递，也会加剧甲醇窜流。另外，还研究了电流变化时电池电压的动态响应，结果表明甲醇窜流对电池动态响应起关键作用。     

梭式窑烟气废热利用的模拟研究

采用商用CFD软件,通过数值模拟和正交实验分析了蜂窝陶瓷的结构参数及各工况条件对换热性能和压力损失的影响,优化了工况参数。数值模拟结果为：进入稳定工作期后,加热期温度效率为94．6％,冷却期温度效率为93．7％,压力损失为457．7Pa。在此基础上,设计了梭式窑高温空气燃烧（HTAC）系统,构建实体模型进行实验,研究余热回收系统的温度效率及烟气在蜂窝陶瓷内压力损失。研究结果表明,加热期与冷却期的温度效率分别为：92．0％,93．2％,测量热烟气和预热空气的压力损失分别为126．3,107．8Pa。     

Indirect fuel cell based on a redox-flow battery with a new structure to avoid cross-contamination toward the non-use of noble metals

An indirect fuel cell system is constructed. The system is composed of a redox flow battery (RFB) to extract electrical energy and two chemical reactors (anolyte and catholyte regenerators). A quinone as a redox mediator is reduced by a mixture of hydrogen and carbon monoxide in the anolyte regenerator, whereas a polyoxometalate as another redox mediator is oxidized in the catholyte regenerator, followed by a steady-state power generation at the RFB using the two redox mediators as active materials. This system demonstrates how to reduce the amount of platinum required in a proton-exchange membrane fuel cell (PEMFC), especially when using a fuel other than pure hydrogen. The RFB in our system contains two gas-diffusion electrodes (GDEs) with a platinum electrocatalyst to insert a “pure hydrogen gas phase” between the anolyte and catholyte to avoid cross-contamination. These two GDEs participate in the hydrogen evolution reaction and hydrogen oxidation reaction, respectively, and require only a small amount of platinum. In addition, the catalysts used in the anolyte regenerator are rhodium complexes. However, these catalysts are in a dissolved state (molecular catalysts) with micromolar-order concentrations, and very little noble metal is used. A carbonaceous catalyst without platinum is used in the catholyte regenerator. This eliminates the need for a noble metal for the oxygen reduction reaction, which is the main reason why platinum is used in a large amount in a conventional PEMFC. Steady-state operations of the anode side, the cathode side, and the total system are demonstrated in this work. Although a small amount of noble metal is still required at this stage, this work may contribute to the complete elimination of noble metals from a PEMFC.     

Current–voltage characteristics of electrovoltaic and electrophotovoltaic cells

Electrovoltaic (EV) effect provides a way of generating voltage across an unbiased junction under dark. Electrovoltaic (EV) cell in its simplest form is a device based on n⁺–p–n⁺ (or p⁺–n–p⁺) like structure in which if one p–n junction is subjected to an external forward bias, then, a voltage is developed across the other p–n junction such that the n-side gets a negative polarity with respect to the p-side. Connecting to a load across one of the n⁺–p junctions a bipolar transistor can be operated as a three-terminal EV cell. A new device henceforth known as electrophotovoltaic (EPV) cell wherein EV and PV effects could be expected to work cooperatively was also realized. It is based on a structure which is a combination of n⁺–p–n⁺ EV and n⁺–p–p⁺ photovoltaic (PV) cell structures having a common n⁺–p junction and is able to operate in EV, PV and EPV modes. We have developed one-dimensional physical models of EV and EPV cells and have applied them to explain the observed I–V characteristics of an n–p–n silicon bipolar transistor 2N3055 in EV mode and the EPV cell in EV, PV and EPV modes. While the photovoltaic efficiency η_PV decreases slowly with d/L, where d is the thickness and L is the diffusion length of minority carriers in the base region, the electrovoltaic efficiency η_EV has a strong dependence on d/L and decreases sharply with increase in d/L. Transistor 2N3055 with d/L=0.7 demonstrated η_EV>60%, whereas, our EPV cell with d/L>2.7 had η_EV<3%. However, in the EPV cell, the PV and the EV effects were indeed found to work cooperatively and the output power was enhanced in the EPV mode over the PV mode value although the efficiency η_EPV was less than 4.5%. To achieve substantially high values of efficiencies in EV and EPV modes the EPV cell should be designed to have d/L1.     

Fuel cells: History and updating. A walk along two centuries

This paper reviews the history of fuel cells. Its follows the path from the invention of the fuel cell up to present days. Fuel cell types as well as their advantages, disadvantages and principal applications nowadays are explained. History teaches once again that devices perceived by the public as recent inventions, are actually the product of many years (almost two centuries in this case) of arduous research.     

Full day modelling of V-shaped organic solar cell

Folded and planar solar cells are examined with optical simulations, with the finite element method. The maximum photocurrent densities during the full day are compared between cells of different geometries and tilting angles. The change of incident angle and spectrum over time are handled in this analysis. The results show that the light trapping effect of the folded cell makes these cells show higher maximum photocurrent densities than the planar cells during all hours of the day. This is the case for both single and tandem cells. The results also indicate that balancing the currents in the tandem cells by adjusting the active layer thickness may be more cumbersome with the folded tandem cells than the stacked planar cells.     

Economics of hydrogen production and utilization strategies for the optimal operation of a grid-parallel PEM fuel cell power plant

This paper integrates the hydrogen production and utilization strategies with an economic model of a PEM fuel cell power plant (FCPP). The model includes the operational cost, thermal recovery, power trade with the local grid, and hydrogen management strategies. The model is used to determine the optimal operational strategy, which yields the minimum operating cost. The optimal operational strategy is achieved through estimation of the following: hourly generated power, thermal power recovered from the FCPP, power trade with the local grid, and hydrogen production. An evolutionary programming-based technique is used to solve for the optimal operational strategy. The model is tested using different seasonal load demands. The results illustrate the impact of hydrogen management strategies on the operational cost of the FCPP when subjected to seasonal load variation. Results are encouraging and indicate viability of the proposed model.     

Effects of operating conditions on the performances of individual cell and stack of PEM fuel cell

In this study, experiments were carried out to study the effects on the performances of individual cell and stack of PEM fuel cell. In the experiment, there are four key operating conditions that affect the cell performance, and they are gas humidification temperature, cell temperature, assembled torsion, and gas flow rate. A 5-cell stack of PEMFC was used to measure the voltage and current density for individual cell in this experiment. Results reveal that the performances of the center fuel cells are relatively lower than those of the cells on both sides of the stack. It is also shown that stack performance increases with the increase in the anode humidification temperature as well as the center cell of the stack. As for the effect of cell temperature, results indicate that stack performance increases with the increase in cell temperature. It is also disclosed that the performances of individual cell and stack do not change with the increase in the anode gas stoichiometric ratio, but increase with the increase in the cathode gas stoichiometric ratio. In addition, the experiment results also show that the whole stack's performance is enhanced with the increase in the assembling torsion.     

Use of Fluoroscein-EDTA System in Photogalvanic Cell for Solar Energy Conversion

Abstract

Fluoroscein has been used as a photosensitizer in photogalvanic cell for solar energy conversion. EDTA was used as an electron donor. The photopotential and photocurrent generated by this cell were 418 mV and 42 μA, respectively. The effect of various parameters like pH, light intensity, diffusion length, reductant concentration, dye concentration, etc. on the electrical output of the cell has been studied. The current voltage (i–V) characteristics of the cell has also been observed and a tentative mechanism for the generation of photocurrent has been proposed. Performance of the cell was determined in dark at its power point.     

Study for improvement of solar cell efficiency by impurity photovoltaic effect

This paper is to study for efficiency improvement of solar cells by utilizing impurity traps introduced in the band gap of semiconductor, that is, impurity photovoltaic (IPV) effect. It is revealed theoretically that there is a certain energy range where impurity-traps act as stepping stones in two-step excitation of electrons from the valence band to the conduction band under suppression of carrier recombination through such traps. Indium is selected as one of proper impurities that satisfy this condition in crystalline silicon, and theoretical prediction is experimentally verified. A good agreement between theory and experiment is obtained concerned with photoconductive properties. It is concluded that the IPV effect is useful to improve the cell efficiency.     

Experimental study and mitigation of abnormal behavior of cell voltage in a proton exchange membrane fuel cell stack

The aim of this study is to investigate the abnormal behavior of cell voltage in a proton exchange membrane fuel cell stack and a mitigation strategy. The proposed strategy is simple and requires only a three‐way solenoid valve to replace the direct way solenoid valve of the original system. It is applied to a proton exchange membrane fuel cell stack with a dead‐ended anode to verify its validity. The behavior of the cell voltages in the stack is discussed in detail, especially the cell reversal process. The results show that the proposed strategy can significantly reduce the severity of hydrogen starvation. And the maximum power of the stack is increased by 10.67%. It is a sudden increase related to cell reversal mitigation. Uneven hydrogen distribution is the cause of low cell voltage and cell reversal. This strategy increases the cell voltage by increasing the hydrogen content in the anode flow channel downstream. It also significantly reduces the fluctuations in cell voltage and improves the uniformity of the cell voltage. This experimental study contributes to mitigate hydrogen starvation in cells of proton exchange membrane fuel cell stacks in application.     

阴极流道分流进气对燃料电池性能影响的实验研究

针对高工作电流密度下,燃料电池内局部水淹导致的传质损失问题,本研究提出了一种阴极流道多进口分流进气方式。实验研究了三种典型分流口位置及分流进量对电池性能的影响。研究发现随着分流口远离阴极主进气口,电池性能呈现先上升后下降的趋势,且当分流口靠近主进气口时,增加分流量有助于电池性能提升,但分流量的增加对电池性能的提升存在一个极限值;因此,在对电池进行分流进气优化时需综合考虑分流口位置和分流量的影响。当分流口为SIP-30%且分流量为按化学当量比ξc = 0.75取值时,分流进气方式相比传统进气方式,电池的最大功率密度高出17.8%。