【作者】 李春芳；

【导师】 左春柽；

【作者基本信息】 吉林大学 ， 机械设计及理论， 2011， 博士

【摘要】 随着经济迅猛发展,全世界汽车保有量迅速增加,这在对环境造成巨大破坏的同时也使石油资源面临枯竭。世界各国为了解决日趋严重的环境和能源问题,争先恐后的开发清洁能源,以期实现良性循环。太阳能是一种巨大能源,每秒的辐射量相当于500万吨煤。我国地处北半球欧亚大陆东部,幅员辽阔,太阳能资源十分丰富,随着太阳能光电技术的日趋成熟和推广应用,太阳能电池板转换效率大幅提高的同时价格日趋下降,使得太阳能电动车的研究取得了飞速发展。电动车具有高效、节能、噪音低、零排放等显著优点,在环保和节能方面具有不可比拟的优势。太阳能电动车把太阳能技术、电动车技术和其他高科技结合在一起,解决了经济发展造成的能源短缺和环境污染之间的矛盾,将为人类发展做出巨大贡献。本文的主要工作是在小型化、轻量化的指导思想下完成了太阳能电动车整车设计,详细论述了太阳能电动车车身和车架的设计要点；对车身进行了外围流场的数值模拟；提出了一种高效廉价的提高太阳能电池转换效率的新方法；建立了太阳能阵列光伏充电的Simulink数字仿真模型,验证了此方法的有效性。论文主要研究内容如下：1、研究了太阳能电动车的关键技术,论证了发展太阳能电动车的可行性本文首先研究太阳能在我国的分布及可利用情况,从光伏系统、电池系统、动力系统、传动系统和车身-底盘系统五个方面综述了国内外太阳能电动车的研究现状,分析了太阳能电动车的关键技术并对开发太阳能电动车的可行性进行了分析。2、构建了太阳能电动车实验和测试平台本文完成的电动车设计是为将来进行太阳能充电实验提供测试平台,设计的总体原则是小型化,轻量化。根据设计要求参数,确定了太阳能电动车的整体方案,并详细论述了车身轻量化重点部位车身和底盘的设计方案。车身外壳由玻璃钢制成,轻便且坚固。顶部具有一较大的平面,用于安装太阳能电池板组件。具有流线外形,降低风阻系数。满足以上条件的前提下,兼顾美观；车架由高强度钢管焊接形成,采用边框式结构。局部具体形状在前后桥设计完成后确定,便于各部件安装及固定；整车的速度采用电控方式,通过输入电动机的电压和功率调节转速及转矩,省略了传统的机械式变速箱和离合器等装置,进一步简化了机构。3、对车身进行数值模拟,根据分析结果改进车身造型车辆的空气动力学已逐步发展成为空气动力学的一个独立分支。设计空气动力性能良好的车辆,是提高其动力性和经济性的重要途径。由于目前太阳能电池板的转换效率较低,太阳能电动车设计定位主要针对短途、车速低、单人使用的电动车。本文根据电动车实际行驶环境,进行了基于空气动力学的车身设计。应用ANSYS ICEM-CFD软件划分网格,选用标准κ-ε高雷诺数模型作为湍流模型,在N-S方程的基础上采用fluent软件进行计算,根据分析结果优化车身造型。从阻力和升力系数的对比可以看出优化后模型分析结果好于原始模型,行驶起来风阻小,动力性、经济性都有很大改善。4、研究了太阳能电池的工作原理和提高太阳能电池转换效率的几种方法本文从太阳能电池的结构、工作原理出发,研究了外界条件对电池的主要性能参数(短路电流、开路电压、填充因子和光电转换效率等)的影响,对现有的几种提高太阳能电池输出效率的方法进行了比较分析,指出了各方法的优缺点5、提出了提高太阳能电池转换效率的新方法目前,太阳能电池光电转换效率低和生产成本高是制约其实用化的关键因素。研究显示太阳能电池板的光伏转换效率随太阳光入射角度增大及工作温度升高而下降。因此减小太阳光入射角度,保证太阳能电池板在最佳的工作温度范围,是提高其转换效率的有效方法。现有太阳能电池系统普遍采用与空气接触,直接散热的方式,优点在于无附加结构,成本低。但散热效果差,电池板温度高,光伏转换效率低。本文提出了一种利用水冷系统提高太阳能电池转换效率的新方法,通过在电池板表面增加滴流装置降低电池的运行温度。用水流进行表面冷却的一个好处是通过热交换带走热量,另一方面由于水的折射使入射角减小,从而增加了辐射的吸收。实验证明,此方法能以较低的成本有效的提高电池的转换效率。研究表明表面水冷方式只适用于电池的静态发电,不能满足太阳能电动车在行驶中使用。由此进一步研究了一种具有微流控散热结构的车载太阳能电池系统。此系统由水泵带动水在迷宫流道中循环流动,使太阳能电池板散热迅速且均匀,不仅提高了转换效率而且能满足车辆行驶要求。以上研究结果表明,论文设计的太阳能电动车满足小型化、轻量化要求,车身外围流场的数值模拟结果显示空气阻力满足要求,得到了较为理想的车身设计方案。本文研究的通过水冷提高太阳能电池转换效率的方法成本低、效果明显,具有普遍推广应用的价值,推动了太阳能电动车的实用化进程。更多还原

【Abstract】 With the explosive economic development and rapid increase in car ownership worldwide, the environment has suffered massive destruction in addition to the depletion of oil resources. In order to resolve the increasingly acute world environmental and energy issues, all nations rushed the development of clean energy in order to achieve a virtuous circle.Solar energy is a tremendous energy with the amount of radiation per second equivalent to 500 tons of coal. Since China is located in northern Eurasia of the northern hemisphere with a vast territory and abundant solar energy resources, solar photovoltaic technology has been promoted into application as a result of its maturity. Substantial increase in conversion efficiency of solar panels combined with declining prices contribute to rapid development in the research of solar electric vehicles. Electric vehicles are characterized by high efficiency, energy saving, low noise, zero emissions and other unparalleled significant advantages in environmental protection and energy saving. The perfect combination of solar technology, electric vehicle technology and other high technology as well ensure that the solar electric cars can cope with the contradiction between energy shortage and environmental pollution caused by the economic development and will subsequently make a great contribution to human development.The main work is to achieve the design for the overall solar electric vehicle under the guiding ideology of being small in size, lightweight too. It introduces the key for design in detail as to the body and frame. On this basis, the body is optimized for the design and performance simulation analysis. It, consequently, puts forward a new and cheap method to improve solar cell conversion efficiency. Meanwhile, it establishes the digital model of solar cell Simulink. The feasibility has been confirmed. The main work can be summarized as follows:1. Of the key technologies and feasibility analysis of solar electric carThis paper studies the distribution and availability of solar energy in China, summarizing the current research of domestic and international solar electric car from five aspects, namely the PV systems, battery systems, power systems, transmission and body-chassis systems, analyzing the key technologies of solar electric vehicle in addition to the feasibility of solar electric vehicles. 2. Construction of experiment and test platform for a solar electric carThe coming design of electric car aims to provide a test platform for the future experiment associated with solar-based power supply. The overall principle is small in size, lightweight. The overall program of solar electric vehicles is determined according to the parameters in the design. Furthermore, it discusses the design program for the significant parts like body and chassis so as to achieve lightweight in detail.Steel body shell is made from glass, light and strong, which has streamlined shape and can reduce the drag coefficient. The top has a larger plane for installing solar panels components. This car might satisfy the premise of the above conditions, taking aesthetic quality into consideration. The frame will be formed by the welding of high strength steel together with the use of frame-type structure. The local shape is to be determined by the completion of the design for bridge.This is easy to install and fix parts. Driven by electronic control means, the input voltage and power the motor speed and torque regulation, it omits the traditional mechanical gearbox and clutch and other devices, further simplifying the organization.3. Of the body to simulate and shape optimization based on the analysis resultsAerodynamics of the vehicle has gradually developed into an independent branch of aerodynamics. Good aerodynamic design of vehicles is an important way to increase its power and economy. Due to the low efficiency of current conversion of solar panels, solar electric cars are designed mainly for short-distance, low speed, single-use electric vehicles.In view of the actual driving environment, the electric vehicles were based on aerodynamic body design. ANSYS ICEM-CFD software will be applied to mesh, with a standard model as a high Reynolds number turbulence model, using fluent software for calculation based on the NS equations. The body shape is optimized based on the analysis. Seen from the comparison of drag coefficient, the optimized model can be better than the original model due to the fact that the wind resistance is smaller and powers as well as economy have been greatly improved.4. Studying the working principle of solar cells and presenting a couple of methods to improve the efficiency of solar cells conversion.This article intends to study the effects upon the main parameters of the battery (short circuit current, open circuit voltage, fill factor and energy conversion efficiency, etc.) from the solar cell structure, working principle, and the external conditions. It also compares several solar cell output efficiency, pointing out their strengths and weaknesses respectively.5. Proposing a new method to improve the conversion efficiency of solar cellsCurrently, the low solar cell conversion efficiency plus the higher production costs is the key factor to restrict it pragmatically. Studies have shown that solar conversion efficiency of photovoltaic solar panels decease with the increase of incident angle and rising working temperature. It is an effective method, therefore, to improve the conversion efficiency through reducing the incidence angle of sunlight and ensuring the best operating temperature range for solar panels.The existing solar cell systems commonly used employ the way of being in contact with air and direct cooling. The advantage lies in no additional structure in addition to low cost. But it is apparent that cooling effect is poor, solar panels have high temperature, and photovoltaic conversion efficiency is low.This paper proposes a use of water-cooling system to improve the conversion efficiency of solar cells as a new method. Additional trickle device is attached to the surface of solar panels to reduce operating temperature. One of the advantages concerning Surface cooling with water flow is that the heat become minimized through the heat exchange. On the other part, with the angle of water refraction decreasing, the absorption of radiation increase. Experiments show that this method can effectively improve the conversion efficiency of the battery at a low cost.The results show that surface water cooling is only available for battery static electricity, while it can not supply the solar electric vehicle in motion. Thus, a further cooling with micro fluidic structure of solar car battery system is explored. This system is driven by the water pump in the water circulation in the labyrinth, which guarantees the quick and even heat flow of solar panels. It can not only improve efficiency but also meet driving requirements.The study suggests that the solar electric vehicles designed by this paper can meet the small-in-size, lightweight standard. The simulation statistics on the part of flow field around solar electric car reveal that air resistance can meet the requirements. It would definitely be an ideal body design. This study further confirms that it is an effective and economical method to increase the efficiency of solar cells through water cooling. With The value of universal application, the practical process of solar electric vehicles can be highly promoted.更多还原