Analysis of effects of front and back surface dopants on silicon vertical multi-junction solar cell by 2D numerical simulation

The silicon vertical multi-junction(VMJ)solar cell has a good potential in high concentration,but it requires high quality front and back surface passivation layers to keep its high efficiency.We try to add dopants into the front and back surfaces of the VMJ cell to release this strict requirement in this work.The effects of recombination velocities,doping types and doping profiles of front and back surfaces on the performance of the P-type VMJ cell were calculated under 1 sun and 1000 suns.The 2D numerical simulation tool TCAD software was used.The performance of the VMJ cell without front and back surface dopants was also calculated for comparison.It was found that the requirement of high quality front and back surface passivation layers could be released remarkably by adding either N-type or P+-type front and back surface dopants.For the two types of front surface dopants,the highest efficiencies of the cells were got by light dopant;for the two types of back surface dopants,the doping type and profile affected little on the performance of the cell in our calculation range.It was also found that the series resistance of the VMJ cell with N-type front surface dopant was decreased by the 2D effect of front surface emitter.The VMJ cell with P+-type front surface dopant had the highest efficiency under 1000 suns and the VMJ cell with N-type front surface dopant had the highest efficiency under 1 sun in our calculation range.     

Experimental and numerical analysis of the hydraulic and thermal performances of the gradually-varied porous volumetric solar receiver

A gradually-varied porous structure is designed to increase the thermal performance of the porous volumetric solar receiver.Based on the replica method and multilayer recoating technique, the silicon carbide porous ceramic with linear-changed geometrical parameters is fabricated. The performances of the uniform and gradually-varied porous volumetric solar receivers are studied by both experiment and numerical simulation. An optimization method combining genetic algorithm and computational fluid dynamics analysis is applied to determine the optimum porosity distribution. The results present that porous volumetric solar receiver with linear-changed geometrical parameters exhibits better thermal performance than the uniform porous volumetric solar receivers, especially when the thickness of the receiver is small. Larger porosity in the front is beneficial for increasing the solar radiation penetration depth, which limits the reflectance and thermal radiative losses. Smaller porosity in the rear traps more solar radiation and increases the convective heat transfer. When the receiver's thickness is larger, the performance of the gradually-varied volumetric solar receiver is nearly identical to that of the uniform receiver with largest porosity. The double-layer configuration is found to be the optimized structure of the gradually-varied porous volumetric solar receiver. The thermal efficiency could be further improved using genetic algorithm with an 11 K increase of the outlet temperature.     

补偿掺杂i层对n-ZnO/i-ZnO/p-Si薄膜太阳能电池性能影响的模拟研究

提出一种新型n-ZnO/i-ZnO/p-Si太阳能电池结构,使用AMPS软件对该结构太阳能电池进行了模拟研究,探索H,N杂质补偿掺杂形成本征i层对该结构太阳能电池的影响。研究发现在掺杂浓度为H=1.7×1017,N=2.8×1017时太阳能电池的转换效率可达15%,并对其转换机理进行了研究。     

n-i-p型非晶硅太阳电池中p/ITO界面特性研究

采用射频等离子体增强化学气相沉积(RF-PECVD)技术,制备n-i-p型非晶硅(a-Si)太阳电池,采用反应热蒸发法制备ITO薄膜作为太阳电池的前电极。通过改变B2H6的掺杂浓度获得了不同晶化率的p层,详细研究了p层性能对p/ITO界面特性以及电池性能的影响。结果表明,在合适晶化率的p层上沉积ITO薄膜有利于优化p/ITO界面的接触特性,将其应用于n-i-p型a-Si太阳电池,能够显著改善电池的开路电压(Voc)和填充因子(FF),最终,在不锈钢(SS)衬底上获得了转换效率为6.57%的单结a-Si太阳电池。     

不同曲率下日光温室钢骨架变形特性分析

在宁夏地区大量的拱形日光温室的建造和维修过程中,日光温室钢骨架普遍存在拱形前屋面后段较为平缓的现象,这一现象会对目光温室的应用造成不利影响．针对不同曲率的前屋面拱架后段钢骨架建立数值分析模型,应用有限元软件进行数值模拟,分析了日光温室前屋面拱架后段不同曲率条件下的结构承载力及变形特点,发现钢骨架的弯曲程度不同,对其承栽能力以及钢骨架整体变形形式都会造成明显的变化,曲率半径越小其承载力越大,并提出在加工钢骨架时应使其后段整体保持一定程度的弯曲以提高其承载力及抵抗变形的能力．为进一步规范我区日光温室钢骨架加工及维修提供参考．     

太阳能电池最大功率点跟踪仿真研究

在太阳能电池电路模型和数学模型的基础上,利用Simulink模块搭建太阳能电池仿真模型,通过设定光照强度,能准确直观地反映出太阳能电池输出特性以及最大功率点的存在,验证了太阳能电池输出的非线性．在此基础上,分析了占空比扰动算法跟踪最大功率点的原理,结合DC／DC变换器实现了太阳能电池输出的最大功率跟踪,使太阳能电池能够迅速达到最大功率点附近并维持在最大功率点附近,为有效提高太阳能的利用率和系统的输出功率提供了一种新的方法．     

利用微纳结构提高太阳能薄膜电池效率

太阳能电池的吸收效率低是制约太阳能电池性能的主要因素之一。为了解决这一问题提出了一种新的结构模型。该模型可以激发局域表面等离子体共振、表面等离子体共振、光子模式、磁极子激元这4个效应。通过时域有限差分法对该模型的效果进行了模拟,并对其结构进行优化,从而使各个效应能够互相耦合,使吸收层吸收率达到一个优值。结果表明,最终优化完成的结构的总体提升系数较常规太阳能电池提高了2.39倍。     

光伏电池输出特性与最大功率点跟踪研究

根据太阳能电池内部结构和等效电路研究其输出伏安（I-V）特性,利用Matlab工具,使用牛顿迭代法求解伏安特性,模拟不同太阳光照强度、环境温度下的光伏阵列I-V特性。同时基于扰动观测法,对光伏系统的最大功率点跟踪进行了仿真研究。     

界面态对ZnO／AlSb太阳能电池性能影响的模拟研究

运用AMPS软件对n-ZnO／i—AlSb／p—A1Sb异质结太阳能电池的性能进行模拟,针对n／i异质结界面态对电池填充因子和转换效率的影响进行研究。结果表明,随着界面态密度增大,电池的填充因子和转换效率迅速下降,具体表现为界面态密度的增加促进光生载流子的复合从而电池并联电阻减小,最终导致电池的转换效率降低。     

水库坝前水温结构日变化规律研究

水库水温结构受来流水温和气象要素的影响,在年内呈现周期性变化,但对其日内变化规律的认识较为缺乏。以龙滩水库为研究对象,于2011年11月～2012年9月分六期对龙滩水库坝前水温进行了原型观测。资料分析结果表明：龙滩水库库区水温除1月外,其余各月均存在分层现象,在7月和9月出现了双温跃层;表层水温年内变化较大,库底水温全年较为稳定;气象要素对坝前水温影响深度与季节有关,夏季影响深度最大;气温越高水温最大值出现的时间越早;水温结构日变化的影响因素主要是气温和太阳辐射,此外坝前水温结构日内变化明显的范围仅为库表20m以内,表层水温的日内变化几乎不对电站发电取水水温构成影响。     

A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally

A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally (3D-cell) is proposed in this paper. We studied its performance both in solar simulator and in nature sunlight. Spiral photo-electrode of 3D-cell can receive sunlight from all directions and therefore can track the sun passively. And it is much insensitive to solar azimuth angle and shade. In addition, it increases the area to obtain scattered sunlight and reflected light. Compared with the dye-sensitized solar cells using sandwich structure, it would be more advantageous in the sealing technique.     

益阳市典型天气条件下3种硅太阳能电池的光电效率测试比较

测试了益阳市4种典型天气（晴天、少云、多云、阴雨）条件下的太阳能单晶硅电池、多晶硅电池、非晶硅薄膜电池的性能参数,比较了3种太阳能电池的光电转换效率,测试结果表明：在晴天和少云的天气下,单晶硅太阳能电池效率最高,约为10.0%左右,多晶硅电池次之,为9.0%左右,非晶硅电池的光电效率最低,为4.5%左右,随着云层的增厚,单晶硅、多晶硅电池光电效率下降,而非晶硅薄膜电池光电效率略有上升,该测试结果对长江中游地区应用太阳能光伏系统具有一定的参考价值.     

透明插板对太阳能烟囱通风的增强效应

为了提高太阳能烟囱的热效率,通过在烟囱内部增设构件,探究增加热边界层数量对烟囱通风的增强效应. 在高1.2 m 宽0.4 m 深0.5 m 的太阳能烟囱实验模型中,插入玻璃板,通过测量烟囱入口段流速的变化,研究透明插板对太阳能烟囱通风量的提高效果. 实验在相对封闭的大厅中进行,并在烟囱入口处布置挡风板以排除环境风速的干扰. 从10月到12月间,共获得7组实际太阳辐射下烟囱的通风量,包括内部有无插板的对比实验. 结果表明,烟囱流量主要与吸热板的得热量有关. 在太阳辐射强度几乎不变的情况下,插入1块普通玻璃板可使得烟囱通风量增加5%~9%. 实验结果证实,在烟囱通道内增加热边界层可以提高烟囱热效率.     

Experimental Study of the Temperature Distribution of Solar Collector Pavement

Black asphalt road have excellent properties to collect the solar radiation and good use of asphalt absorb solar energy is a new energy technology. Asphalt is a sticky plastic material,its modulus and strength will change with temperature and the actual bearing capacity of pavement structure will change as well. A new method was used to evaluate the temperature change of asphalt pavement. By simulate solar radiation on asphalt sample to study the change of the temperature field. The temperature distribution of the asphalt concrete under the same light radiation and circulating water was also studied. The results indicate that this method can be a good simulation of solar collectors on the surface temperature field.     

清末民初马褂标本连裁肩袖线偏斜的纸样技术

通过对清末民初马褂实物标本的测量与复原,发现古典华服的连裁肩袖线存在向前中偏斜,平面结构前身大于后身的现象.通过对衣片结构的模拟复原,运用平测和全息数据采集的方法,进行连裁肩袖线朝前中偏斜不同角度的系列实验,验证了此件马褂标本连裁肩袖线偏斜的结构,并确定了其偏斜角度的范围,此研究可以帮助我们更好地了解古典华服纸样设计的科学性和古人的智慧.     

Effects of different CdCl_2 annealing methods on the performance of CdS/Cd Te polycrystalline thin film solar cells

In this paper, the effects of different Cd Cl2 annealing methods, including vapor annealing and dip-coating annealing, on the performance of Cd S/Cd Te polycrystalline thin-film solar cells are studied. After annealing, the samples are lightly etched with 1% bromine in methanol to remove surface oxides. Both annealing methods give Cd Te polycrystalline thin films with good crystallinity and complete structure. For solar cells containing the annealed Cd Te films, cell efficiency first increases and then decreases as the concentration of Cd Cl2 solution used for dip-coating annealing increases, and the optimized Cd Cl2 concentration is 12%. The uniformity of the performance of all cells is analyzed by calculating the relative standard deviation for each parameter. The uniformity of cell performance can be improved dramatically by dip-coating annealing instead of vapor annealing. Most notably, an appropriate concentration of Cd Cl2(12%) acts as a protective layer that is conducive to realizing uniform high-performance Cd S/Cd Te solar cells. According to the location of depletion regions, the Cd Te films treated by dip-coating annealing show a relatively low doping concentration, except for the sample treated with a Cd Cl2 concentration of 6%, which is consistent with the changes of short-circuit current density of the cells. It is believed that these results can be applied to the large-scale production of Cd Te polycrystalline thin-film solar cells.     

热成型钢板在汽车前横梁上的应用

通过对原有车型前横梁结构进行分析和研究,得出基于目前车型结构,存在两种更改方案。针对双层板和单层板两种设计更改方案,分别采用了两种材料对前横梁进行相应的结构设计,然后再对其进行整车碰撞性能测试、CAE分析。结果表明,采用热成型钢板BTR165设计的前横梁单板结构,相对普通板材B340/590设计的前横梁双层板结构,不仅可以提高整车的碰撞安全性能,而且可以降低汽车的自重,因而具有重要的现实应用意义。     

Studies of key technologies for CdTe solar modules

In this paper, CdS thin films, which act as the window layer and n-type partner to the p-type CdTe layer, were prepared by chemical bath deposition (CBD). CdTe thin films were deposited by the close-spaced sublimation (CSS) method. To obtain high-quality back contacts, a Te-rich layer was created with chemical etching and back contact materials were applied after CdTe annealing. The results indicate that the ZnTe/ZnTe:Cu complex layers show superior performance over other back contacts. Finally, by using laser scribing and mechanical scribing, the CdTe mini-modules were fabricated, in which a glass/SnO₂:F/CdS/CdTe/ZnTe/ZnTe:Cu/Ni solar module with a PWQC-confirmed total-area efficiency of 7.03% (54 cm²) was achieved. Supported by the Hi-Tech Research and Development Program of China (Grant No. 2003AA513010), and the Science and Technology Program of Sichuan Province, China (Grant No. 05GG021-003-3)     

光伏电池最大功率点跟踪芯片的设计

为提高光伏电池的光电转换效率,设计一种基于开路电压法的光伏电池最大功率点跟踪（MPPT）控制芯片.利用光伏电池开路电压与最大功率点电压存在近似线性关系的特性,周期性采样光伏电池的开路电压,计算得到最大功率点电压.所设计的芯片结构简单、成本低、稳定性好,除能够较精确地控制实现光伏电池的MPPT外,还能周期采样、定时更新当前MPPT电压,并实时监测光伏电池的输出电压,使环境条件变化时系统具有快速的动态响应.芯片除包含参考基准、电压调节器、振荡器及误差放大器等基本模块外,还集成了采用自举技术的驱动电路,提高了输出电压.电路采用1.5 μm双极型-CMOS-DMOS （BCD）工艺设计制造,优化后的芯片面积约为3.0 mm×2.6 mm.测试结果表明,预期的电路功能已经基本实现.     

基于前后台码的产品信息分类编码系统的开发研究

根据信息化企业对产品信息分类编码的要求,提出了一种新颖的前后台码的产品信息分类编码系统,并庆用于某企业的ＰＤＭ和ＭＲＰⅡ的实施工作中,实施实践表明,前后台码的体系结构可以满足ＰＤＭ和ＭＲＰⅡ对产品信息分类的需求,有助于这些系统在企业的顺利实施。