高倍聚光GaInP/InGaAs/Ge三结太阳电池研究

在综述高倍聚光GaInP/InGaAs/Ge三结太阳电池的研究现状与发展趋势的基础上,对高倍聚光太阳电池的关键技术、性能提升方法和可靠性进行了研究。指出提高隧穿电流和降低串联电阻是高倍聚光三结太阳电池的关键技术,并提出了相应的解决方法。采用多异质结构隧穿结提高了隧穿电流,减小横向扩展电阻和栅线电阻降低了总的串联损耗。此外,通过分别提高GaInP顶电池和底电池禁带宽度、降低InGaAs中电池禁带宽度可进一步提高太阳电池的转换效率。最后探讨了高倍聚光太阳电池的可靠性测试标准。     

聚光光伏技术及研究进展

<正>聚光光伏技术是指利用光学元件将太阳光汇聚后,通过高转化效率的光伏电池(GaAs基)直接转换为电能的技术,被认为是太阳能发电未来发展趋势的第三代技术,即聚光光伏(CPV)。1.聚光光伏技术概述GaAs基太阳能电池可分为单结和多结叠层式太阳能电池两类。GaAs、Ge单结太阳电池理论效率27%,实验室效率达到     

透镜与电池间距对聚光光伏系统特性影响的实验研究

实验研究了聚光太阳电池上光照强度、短路电流、开路电压、电池温度和光电转换效率随菲涅耳透镜与电池的距离变化关系。结果表明,聚光条件下,太阳电池性能的提高主要源于短路电流的变化,而不是开路电压;聚光后,太阳电池与透镜距离为焦长时,输出功率可以达到最大值;太阳电池的最大单位光强转换效率需要把太阳电池放到透镜焦点前。本文研究结果对于聚光光伏系统的研制具有指导意义。     

槽式聚光太阳能系统太阳电池阵列

基于槽式聚光太阳能系统分别对单晶硅电池阵列、多品硅电池阵列、空间太阳电池阵列和砷化镓电池阵列进行测试实验.结果表明,聚光后,前3种电池阵列的Ⅰ-Ⅴ曲线都趋于直线,输出功率急剧减少,系统效率下降较快.而砷化镓电池阵列有较好的Ⅰ-Ⅴ曲线,其效率由聚光前的23.66%增加到26.50%,理论聚光比为16.92时,输出功率放大11.2倍,聚光光伏系统中町采用砷化镓电池阵列以提高效率.砷化镓电池阵列Pm、FF和η的温度系数分别为-0.12W/K、-0.10%/K和-0.21%/K,为避免温度的影响须采用强制冷却方式保证电池效率,同时对外供热.研究表明,10片单晶硅电池串联阵列最佳工作时的理论聚光比为4.23;16片空间太阳电池串联阵列最佳工作时的理论聚光比为8.46.研究工作对提高槽式聚光系统效率和大规模利用聚光光伏发电提供了依据.     

槽式聚光太阳能系统太阳电池阵列

基于槽式聚光太阳能系统分别对单晶硅电池阵列、多晶硅电池阵列、空间太阳电池阵列和砷化镓电池阵列进行测试实验. 结果表明,聚光后,前3种电池阵列的I-V曲线都趋于直线,输出功率急剧减少,系统效率下降较快. 而砷化镓电池阵列有较好的I-V曲线,其效率由聚光前的23.66%增加到26.50%,理论聚光比为16.92时,输出功率放大11.2倍,聚光光伏系统中可采用砷化镓电池阵列以提高效率. 砷化镓电池阵列Pm、FF和η的温度系数分别为-0.12W/K、-0.10%/K和-0.21%/K,为避免温度的影响须采用强制冷却方式保证电池效率,同时对外供热. 研究表明,10片单晶硅电池串联阵列最佳工作时的理论聚光比为4.23; 16片空间太阳电池串联阵列最佳工作时的理论聚光比为8.46. 研究工作对提高槽式聚光系统效率和大规模利用聚光光伏发电提供了依据.     

光强和温度对多结太阳电池的影响研究

基于模拟太阳光源的方法,在室内研究了在不同光照强度、不同工作温度下GaAs多结太阳电池的输出特性.通过实验得出:随着光源辐照强度的增加,太阳电池的特性参数:短路电流Isc线性增加,开路电压Voc对数增加,最大输出功率P线性增加,光电转换效率η随聚光比增加到一定程度后减小.对比分析了光强和温度对电池输出特性的影响,数据结...     

硅微纳结构及其在新型太阳电池中的应用

综述了近年来各种硅微纳结构的特征和制备技术,介绍了其在新型太阳电池中的应用现状与前景.首先,阐述了硅微纳结构在传统p-n结、新型径向p-n结以及异质结太阳电池结构设计中的研究进展;其次,从光吸收增强、表面修饰及钝化的角度,分析了硅微纳结构太阳电池的增效措施;最后,提出了柔性硅微纳结构太阳电池开发的新思路.     

基于光纤温度传感器监测的聚光光伏发电系统

针对聚光型太阳能光伏电池能量转换效率和使用寿命受温度影响较大的问题,基于砷化镓半导体吸收式光纤温度传感器,提出一种对聚光光伏发电系统的温度进行实时监测和控制的方法。数值仿真实验结果表明,当冷却水的流速降低、聚光光伏电池工作温度升高时,半导体的吸收波长增加,光纤温度传感系统检测出来的温度较高,这时可以通过节流阀增加冷却水的流速,提高聚光光伏电池与冷却水之间的传热系数,从而降低聚光光伏电池的温度。该方法对于延长聚光光伏电池的使用寿命和提高太阳能的利用率具有一定的理论指导意义。     

PERC结构多晶硅太阳电池的研究

高效、低成本是目前硅太阳电池追求的主要目标。多晶硅太阳电池成本低,但其电性能较差。背面钝化及局部背接触是提高多晶硅太阳电池电性能的主要技术。通过采用SiO2/SiNx叠层膜作为背钝化介质层,依次经过背面开槽、丝网印刷、烧结形成背面局部接触,制备钝化发射极和背表面电池(PERC)结构多晶硅太阳电池。采用恒光源I-V特性测试系统测试其电性能,结果表明:较之常规铝背场多晶硅太阳电池,PERC结构电池在开路电压Voc、短路电流密度Jsc、转换效率η方面分别提高了13 mV、1.8 mA/cm2和0.67%(绝对值),其转换效率达到17.27%。PERC结构多晶硅电池采用了常规丝网印刷工艺,有利于实现高效多晶硅电池的产业化生产,具有很高的实际意义。     

CdS/CdTe叠层太阳电池的制备及其性能

CdS/CdTe太阳电池是薄膜太阳电池研究工作的一个重要方向.为了提高开路电压Voc、改善电池的光谱响应,进而提高电池的转换效率,在此提出CdS/CdTe叠层太阳电池结构.文中,叠层电池的顶电池由CdS/CdTe超薄层构成;底电池由CdS/CdTe薄膜层构成.经分析测试,实验制备的CdS/CdTe叠层太阳电池具有明显的叠层结构,开路电压最高达到了852mV,短路电流密度最大为13mA/cm2,填充因子最高为55.2%,这种叠层电池的效率达到了8.16%(0.071cm2).研究表明相对于传统的单层CdS/CdTe太阳电池,CdS/CdTe叠层电池的制备对研究如何提高CdS/CdTe太阳电池的光伏性能有一定的参考价值.     

Optimization of grid design for solar cells

By theoretical simulation of two grid patterns that are often used in concentrator solar cells, we give a detailed and comprehensive analysis of the influence of the metal grid dimension and various losses directly associated with it during optimization of grid design. Furthermore, we also perform the simulation under different concentrator factors, making the optimization of the front contact grid for solar cells complete.     

太阳能电池栅电极优化设计

本文通过对聚光电池中常用的两种电极结构进行理论模拟,全面具体地分析了电池尺寸以及与电池上电极有关的各种损耗对栅电极优化设计的影响;并且对电极优化设计在不同聚光因子下的影响也进行了模拟,使太阳电池栅电极的优化设计更加完整。     

Maximization of conversion efficiency based on global normal irradiance using hybrid concentrator photovoltaic architecture

Maximization of module conversion efficiency based on global normal irradiance (GNI) rather than direct normal irradiance (DNI) was experimentally demonstrated using a hybrid concentrator photovoltaic (CPV) architecture in which a low‐cost solar cell (a bifacial crystalline silicon cell) was integrated with a high‐efficiency concentrator solar cell (III–V triple‐junction cell) to harvest diffuse sunlight. The results of outdoor experiments showed that the low‐cost cell enhanced the generated power by factors of 1.39 and 1.63 for high‐DNI and midrange‐DNI conditions, respectively, and that the resultant GNI‐based module efficiencies were 32.7% and 25.6%, respectively. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

Evaluation of the reliability of high concentrator GaAs solar cells by means of temperature accelerated aging tests

Evaluating the reliability, warranty period, and power degradation of high concentration solar cells is crucial to introducing this new technology to the market. The reliability of high concentration GaAs solar cells, as measured in temperature accelerated life tests, is described in this paper. GaAs cells were tested under high thermal accelerated conditions that emulated operation under 700 or 1050 suns over a period exceeding 10 000 h. Progressive power degradation was observed, although no catastrophic failures occurred. An Arrhenius activation energy of 1.02 eV was determined from these tests. The solar cell reliability [R(t)] under working conditions of 65°C was evaluated for different failure limits (1–10% power loss). From this reliability function, the mean time to failure and the warranty time were evaluated. Solar cell temperature appeared to be the primary determinant of reliability and warranty period, with concentration being the secondary determinant. A 30‐year warranty for these 1 mm²‐sized GaAs cells (manufactured according to a light emitting diode‐like approach) may be offered for both cell concentrations (700 and 1050 suns) if the solar cell is operated at a working temperature of 65°C. Copyright © 2012 John Wiley & Sons, Ltd.     

High‐irradiance degradation tests on concentrator GaAs solar cells

The present work summarises the results of an experiment of light‐soaking high‐concentrator MOVPE‐grown GaAs solar cells under monochromatic light (808 nm). The irradiance level was set so that the short‐circuit current obtained was 1100 times that produced with the AM1ċ5D spectrum at 1 kW/m². This test caused no morphological changes in the devices. The main phenomenon discovered has been a slight increase with time of the reverse current I₀₂. This increase is analogous to that observed in similar degradation experiments based on high forward currents. In general, the results of these tests show that the drop in performance is very limited, supporting the idea that concentrator GaAs solar cells are rugged devices, capable of achieving long lifetimes in field operation. Copyright © 2003 John Wiley & Sons, Ltd.     

单体聚光太阳电池的热分析和温度测试

A thermal model for concentrator solar cells based on energy conservation principles was designed. Under 400X concentration with no cooling aid, the cell temperature would get up to about 1200 ？C. Metal plates were used as heat sinks for cooling the system, which remarkably reduce the cell temperature. For a fixed concentration ratio, the cell temperature reduced as the heat sink area increased. In order to keep the cell at a constant temperature, the heat sink area needs to increase linearly as a function of the concentration ratio. GaInP/GaAs/Ge triple-junction solar cells were fabricated to verify the model. A cell temperature of 37 ？C was measured when using a heat sink at 400X concentration.     

Determination of spectral variations by means of component cells useful for CPV rating and design

A methodology is presented to determine both the short‐term and the long‐term influence of the spectral variations on the performance of multi‐junction (MJ) solar cells and concentrator photovoltaic (CPV) modules. Component cells with the same optical behavior as MJ solar cells are used to characterize the spectrum. A set of parameters, namely spectral matching ratios (SMRs), is used to characterize spectrally a particular direct normal irradiance (DNI) by comparison to the reference spectrum (AM1.5D‐ASTM‐G173‐03). Furthermore, the spectrally corrected DNI for a given MJ solar cell technology is defined providing a way to estimate the losses associated to the spectral variations. The last section analyzes how the spectrum evolves throughout a year in a given place and the set of SMRs representative for that location are calculated. This information can be used to maximize the energy harvested by the MJ solar cell throughout the year. As an example, three years of data recorded in Madrid shows that losses lower than 5% are expected because of current mismatch for state‐of‐the‐art MJ solar cells. Copyright © 2015 John Wiley & Sons, Ltd.     

Validated front contact grid simulation for GaAs solar cells under concentrated sunlight

In a common approach, the electric behavior of a solar cell is modeled by dividing it into smaller sub‐circuits and solving the resulting network by a circuit simulator. In this paper detailed network simulations are presented for a GaAs single‐junction solar cell. All resistive losses and losses influencing the diode saturation currents, such as recombination in the depletion region or at the perimeter are taken into account. With this model the maximum power point of a solar cell can be calculated for one‐sun and for higher illumination intensities. The results were validated experimentally using suitable test structures. This includes solar cell devices with varying dimensions, grid finger spacing and lengths. An excellent agreement between theoretical and experimental results was obtained. The network simulation model allows determining the optimum size and concentration ratio at which a solar cell operates at its maximum efficiency. In the case of a GaAs single‐junction solar cell this global efficiency maximum was found for an area of 1 mm² and at a concentration ratio of 450 suns. Under these conditions the largest loss mechanisms are the finger shading with 36.1% and the emitter resistance losses with 21.5% of the total power losses. Copyright © 2010 John Wiley & Sons, Ltd.     

Spectrally and angle‐resolved emission of thin film fluorescence collectors

Fluorescence collectors (FSCs) offer the possibility to collect and concentrate direct and ambient light and are, thereby, an option to decrease the cost of high‐efficiency solar modules. So far, scattering, absorption and reabsorption of the incoming and fluorescence light cannot be discriminated completely in experiments. Thus, the contribution to the discrepancy of experimentally achieved efficiencies from the theoretical one has not been identified. To understand the propagation of the fluorescence light by illumination at a certain distance from the edge of the FSC, we have developed a two‐dimensional analytical model based on geometrical optics that reproduces the experimental results. Under certain conditions for each distance from the edge regimes of detection angles exist for which no fluorescence light of the edge occurs. Copyright © 2011 John Wiley & Sons, Ltd.     

Design,fabrication, and analysis of transparent silicon solar cells for multi‐junction assemblies

Transparent silicon solar cells can lead to an increased efficiency of silicon‐based multi‐junction assemblies by transmitting near and below band gap energy light for conversion in a low band gap solar cell. This analysis shows that the maximum efficiency gain for a low band gap solar cell beneath silicon at a concentration of 50 suns is 5.8%, based on ideal absorption and conversion of the photons. This work analyzes the trade‐offs between increased near band edge absorption in the silicon and silicon solar cell transparency. Application of these results to real cases including a germanium bottom solar cell is analyzed, leading to a range of cases with increased system efficiency. Non‐ideal surfaces and real silicon and germanium solar cell device performance are presented. The range of practical system gains may be as low as 2.2 – 1% absolute when compared with the efficiency of a light‐trapped silicon solar cell for 1‐sun operation, based on this work. Copyright © 2012 John Wiley & Sons, Ltd.