太阳能电池多晶硅表面激光制绒技术研究进展

太阳能作为一种绿色可持续的清洁能源，可以转化为热能或电能，是传统能源最重要的替代品。多晶硅太阳能电池由于具有较低的成本而被广泛用于光伏发电领域，降低多晶硅片表面反射率是提升多晶硅太阳能电池效率的重要手段之一。本文分析了硅基太阳能绒面微结构的吸光原理，梳理了各类常见制绒方法。在此基础之上，总结了激光制绒的各类加工方法，概括了不同激光加工方法对多晶硅片表面绒面产生的相应效果，其中，激光复合方法制绒的效果普遍优于单一激光制绒。随后从激光加工工艺的角度，分析了激光加工主要参数对绒面微结构形貌的影响：由于不同波长下多晶硅材料的吸收率不同，各加工效果亦不相同；通过调整脉冲激光加工中的重复频率、扫描速度等参数，可影响制绒面凹坑间距进而改变绒面微结构的密度，通过调整功率、单脉冲能量等因素则影响微结构的烧蚀程度或深度；而入射角度、能量分布及脉宽对制绒亦有明显效果。对比发现，各典型绒面微结构的形貌中，V形纹理比U形纹理更能有效地捕捉吸收光线，而二维复合型陷光微结构比单一型陷光微结构吸光性更好。在此基础之上，论述了化学后处理对提升多晶硅片绒面质量的作用体现，表明化学后处理能改善或消除多晶硅片经激光制绒后形成...     

多晶硅表面金属催化化学腐蚀法制绒研究现状

在多晶硅太阳能电池的生产过程中,金刚线切割(Diamond wire sawing, DWS)技术具有切割速度快、精度高、原材料损耗少等优点,受到了广泛关注。金刚线切割多晶硅表面形成的损伤层较浅,与传统的酸腐蚀制绒技术无法匹配,金属催化化学腐蚀法应运而生。金属催化化学腐蚀法制绒具有操作简单、结构可控且易形成高深宽比的绒面等优点,具有广阔的应用前景。本文总结了不同类型的金属催化剂在制绒过程中的腐蚀机理及其形成的绒面结构,深入分析和讨论了具有代表性的银、铜的单一及复合催化腐蚀过程及绒面结构和电池片性能。最后对金刚线切割多晶硅片表面的金属催化化学腐蚀法存在的问题进行了分析,并展望了未来的研究方向。     

金刚石线锯切割多晶硅片表面制绒工艺研

晶体硅片的制绒技术是太阳能电池制造工艺中的关键步骤。本研究以工业中酸制绒方法为基础, 研究了腐蚀时间、浓度对绒面结构以及反射率的影响。此外, 还采用金属催化化学腐蚀法进行制绒, 选用氢氟酸和硝酸银作为腐蚀液。而且对两种制绒方法效果进行了对比。研究获得的最优绒面结构及反射率结果的实验条件为: 氢氟酸浓度4.6 mol/L、硝酸银浓度0.02 mol/L, 室温下反应90 min, 得到的平均反射率为8%, 远低于目前多晶硅片制绒生产标准。     

金刚石线锯切割多晶硅片表面制绒工艺研究

晶体硅片的制绒技术是太阳能电池制造工艺中的关键步骤。本研究以工业中酸制绒方法为基础,研究了腐蚀时间、浓度对绒面结构以及反射率的影响。此外,还采用金属催化化学腐蚀法进行制绒,选用氢氟酸和硝酸银作为腐蚀液。而且对两种制绒方法效果进行了对比。研究获得的最优绒面结构及反射率结果的实验条件为:氢氟酸浓度4.6 mol/L、硝酸银浓度0.02 mol/L,室温下反应90 min,得到的平均反射率为8%,远低于目前多晶硅片制绒生产标准。     

超声低温等离子体在太阳能电池表面的改性作用

传统硅基太阳能制备工艺生产出的多晶硅太阳能电池的光电转换效率在17%左右~([1]),难以突破。利用超声低温等离子体设备对电池表面进行处理,结果显示,经过处理后,多晶硅太阳能电池的峰值功率与光电转换效率提升了5%左右。由此推测,利用超声低温等离子体处理多晶硅电池表面的方法,具有使氮化硅表面钝化、去除磷硅玻璃、清洗电池片以及优化表面绒面等作用,因此,利用该技术可提升太阳能电池片的产品性能。     

利用金属辅助化学腐蚀法在硅表面获得纳米绒面结构以提升多晶硅太阳电池效率

在硅片表面制备绒面结构能够有效降低太阳光在硅片表面的反射损失,是提高太阳能电池转换效率的一条重要途径。通过真空热蒸发法在多晶硅片上沉积纳米银颗粒,利用金属辅助化学腐蚀(MACE)法,制备了不同腐蚀时间下的纳米绒面结构,其中,腐蚀时间为60s的纳米绒面的平均反射率低至4.66%(300~1100nm)。同时,对腐蚀时间为60s的纳米绒面用KOH溶液进行优化处理,将KOH处理前后的多晶硅片采用常规电池工艺进行电池制备研究。对比发现,经过KOH处理后的电池效率比未经KOH处理的电池效率提高了0.43%。     

太阳能级多晶硅片表面制绒的研究

主要研究多晶硅太阳能电池片工业制绒的酸腐蚀过程,腐蚀液是由HNO3、HF和H2SiF6组成的混合液,未添加其他试剂作为反应缓释剂;采用SEM和紫外分光光度计对多晶硅片表面制绒形貌进行观察和检测分析。实验过程中,按照工业生产的实际模型,首先研究确定了最佳腐蚀时间为2min,之后主要研究了酸腐蚀过程中的H2SiF6浓度对多晶硅表面制绒效果的影响,优化得到H2SiF6的最低含量为2%,并确定最佳腐蚀工艺条件,为进一步回收利用腐蚀废液提供依据。     

含氟表面活性剂对多晶硅绒面微结构的影响

在酸制绒液中加入含氟表面活性剂,对多晶硅片制绒。然后通过扫描电子显微镜观察多晶硅表面织构,并在此基础上分析含氟表面活性剂对腐蚀效果的影响。实验结果表明:虽然传统酸液对多晶硅制绒是各向同性的,但加入含氟表面活性剂后,酸腐蚀出现各向异性腐蚀特性;由此制备的多晶硅片反射率从25.7%下降到了23.9%,表面出现变形的金字塔、三角形等,且不同晶面的金字塔和三角形的大小和倾斜角度不同。最后根据杨氏理论,从界面张力的角度解释了含氟表面活性剂对制绒的影响机理。     

两步酸修饰的多晶硅绒面结构

本文提出两步法制备多晶硅表面绒面技术,用两次化学腐蚀修饰多晶硅片的表面。实验中首先采用腐蚀液HF/NaNO2/H2O对多晶硅表面进行腐蚀,然后采用腐蚀液HF/HNO3/（NH4）2C2O4/H2O对其表面进一步修饰。通过多晶硅SEM表面形貌图分析,两步法修饰的多晶硅表面有形状如蚯蚓状的腐蚀坑,腐蚀坑的深度和分布密度相对较大。通过反射谱分析了多晶硅片表面陷光效果,并与用其它方法修饰的硅表面陷光效果进行了对比,与传统配方HF/HNO3/H2O获得的多晶硅表面相比,综合平均反射率下降了7%左右。这种方法获得的多晶硅表面能有效收集太阳光,有利于提高太阳能电池的转换效率。     

多晶硅太阳电池表面织构工艺优化

在太阳电池制备工艺中,多晶硅表面常需要进行绒面处理,在各种不同的工艺中,各向同性腐蚀法由于成本低且易于操作而适宜于大规模生产,已成为当前研究的重点。但不同配比的试剂在不同作用时间及工艺下会得到不同的效果,如何科学地评价这些差异,进而得到最佳的工艺参数用于指导生产实践,具有重要的意义。由于各参数间复杂的非线性耦合关系,使得参数的精确确定成为难题。在充分理解遗传算法(Genetic algorithm,GA)作用机理的基础上,以人工神经网络(Artificial neural network,ANN)为辅助手段,以腐蚀速度和光反射率为评价标准,从理论上提出了最佳工艺参数的确定方法,大量多晶硅表面制绒试验已经证明,此方法具有快捷、准确的优点。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.