Heating and cooling battery electric vehicles-the final barrier

Battery electric vehicles (EVs) present a particular challenge to the development of more efficient and effective heating and cooling systems for automotive applications. Because heating-ventilating-air-conditioning (HVAC) systems are electrically powered, vehicle range is reduced when the HVAC system is operating. The alternative solutions to HVAC battery electric vehicles are identified and evaluated. These include a basis for determining HVAC boundary design assumptions and showing mathematical methods for estimating the HVAC load and energy requirements, and evaluation of the new European and Japanese approaches to wintertime heating, such as NaS battery, motor and component waste heat recovery, electric seat warmer, radiant foot warmer, electric windshield and backlight defrost, molten salt latent heat storage, metal hydride hydrogen storage and catalytic heater, and liquid fueled heater     

Comparison of AC drives for electric vehicles-a report on experts'opinion survey

It is recognized that wide applications of electric vehicles (EVs) will bring tremendous social, economical and ecological benefits. With the growing interests in electric vehicles, much effort is demanded for the development of efficient, reliable and economical AC drives' for EV propulsion purpose. Both induction motor (IM) drives and permanent magnet brushless DC motor (IM) drives have been applied to EVs. Switched reluctance motor (SRM) drives have been proposed as an alternative for EV propulsion. In order to assess the suitability of IM, BDCM and SRM drives for EV applications and to provide a technical support for the development and selection of future EV propulsion systems, the existing EV AC propulsion drives were compared, and a survey of experts' opinions was conducted. Comparison of the three AC drives was made on a relative and a quantitative basis using the survey questionnaires. According to the majority of the experts, induction motor drives are best suited for EV propulsion purpose, due to their low cost, high reliability, high speed, established converter and manufacturing technology, low torque ripple/noise and absence of position sensors. BDCM drives feature compactness, low weight and high efficiency and therefore provide an alternative for EV propulsion. The experts regard insulated gate bipolar transistors (IGBTs) as the most suited power semiconductor devices for AC drive converters at the present stage     

Ultra light electric vehicle parameters

A comparative assessment of the applications of ultralight technology to electric vehicles (EV) under development since 1990 has been made. The general nature of the mathematical model permitted EVs of all types, including bicycles and magnetic levitation vehicles, to be evaluated and compared for acceleration levels, elapsed time, and elapsed distance performance in a standardized framework, with acceptable accuracy in comparison to the performance results published in the public domain. The aerodynamic coefficients and the skin friction component of the total aerodynamic drag coefficient could be estimated     

Recent developments of electric vehicles and their propulsionsystems

Major recent electric vehicle (EV) programs in North America, Europe, and Japan are reviewed. The developments discussed include electric vehicles for fleet operation and electric passenger cars for urban transit. All major auto makers have had their own concept electric vehicle programs, targeted at commercial production in the late 1990s. It Is noted that, with different objectives for various electric vehicles, considerations such as cost, reliability, efficiency, maintenance, durability, weight, size, and noise level should be compromised for the propulsion system design. Consequently, DC motor drives, induction motor drives, and permanent magnet brushless DC motor drives will continually be used for EV propulsion systems in the future, with DC drives being gradually replaced by AC drives. The rapid advances in power semiconductor devices and microprocessors have made it possible to build reliable and cost-effective AC drive systems     

Advances in the development of ovonic nickel metal hydridebatteries for industrial and electric vehicles

The environmental advantages of ovonic NiH₂ batteries, due to the nontoxicity of ovonic alloys, are briefly discussed, and their general performance is described. Commercial progress in their development is summarized. Their use in electric vehicles is examined     

New maintenance free nickel-cadmium-traction-batteries in fibretechnology

The fiber plaque technology used in the alkaline Ni-Cd battery system known as FNC (fiber nickel cadmium) is discussed. An advanced design called FNC-Recom, which contains additional fiber plates that are used as a recombination device for rapid oxygen consumption, is described. The FNC-Recom cell design is explained, and performance data and experiences with their use in electric vehicles are reported     

Advanced materials for next generation NiMH portable, HEV and EVbatteries

While Ovonic NiMH batteries are already in high volume commercial production for portable applications, advances in materials technology have enabled performance improvements in specific energy (100 Wh/kg), specific power (600-1000 W/kg), high temperature operation, charge retention, and voltage stability. Concurrent with technology advances, Ovonic NiMH batteries have established performance and commercial milestones in electric vehicles, hybrid electric vehicles, as well as scooter, motorcycle and bicycle applications. As important as these advances, significant manufacturing cost reductions have also occurred which allow continued growth of NiMH technology. In this paper, advances in performance, applications and cost reduction are discussed with particular emphasis on the improved proprietary metal hydride and nickel hydroxide materials that make such advances possible     

无人驾驶飞行器的气动特点和设计

首先论述了发展无人驾驶飞行器(UAV)的重要性,集中介绍了2种UAV的平台,包括:高空长航时UAV和无人战斗机(UCAV)。讨论了这2种飞行器空气动力特点和气动设计的主要问题。对于高空长航时UAV设计中要重点发展的专用翼型的设计,介绍了一种新型的杂交设计思想和提出了基于CFD技术的多目标多点优化设计的工具。讨论了此类飞行器三维机翼设计的基本要求和三维后掠自然层流机翼的设计。UCAV设计中强调了气动/隐身综合设计的重要性,讨论了无尾布局时新型先进气动控制和矢量推进相结合的必要和难点。     

Making batteries last longer [for electric vehicles]

The early 1900's era of electric cars ended because the batteries didn't last long enough, and a new gasoline-engine-powered car cost less than a replacement battery. Long-life batteries are the key to achieving a low life-cycle cost for the electric vehicles that will help solve the air-pollution problem in our cities. New ways of making batteries last longer are discussed     

Perspective on ultracapacitors for electric vehicles

Recent advances in performance of chemical double layer capacitors (DLC) with aqueous and non-aqueous electrolytes have made it possible to seriously consider them for commercialization. Non-aqueous (organic) carbon based laboratory monopolar devices have recently met key U.S. Department of Energy (DoE) mid-term specifications (> 5 WNkg, >500 W/kg and >100,000 life cycles) for load-leveling electric vehicles batteries. All DLC technologies currently under development by DoE are discussed. Each technology has distinct advantages and none are clear winners at this time. A study has been completed by the General Electric Company on the interface electronics needed to best utilize the energy of capacitors for load-leveling batteries. System costs are presented based on this study, several battery technologies, and capacitor projections     

Electric vehicles (EVs): `a look behind the scenes'

The author addresses and summarizes some of the broader issues relating to electric vehicles including legislation, regulation, funding, infrastructure, niche markets, safety, and the near-term need for lead-acid batteries. The impact of low emission requirements is examined. The principle hazards associated with lead-acid batteries and the attendant liability issues are identified. Federal safety requirements are discussed in some detail     

Electric-vehicle batteries

Electric vehicles that can't reach trolley wires need batteries. In the early 1900's electric cars disappeared when owners found that replacing the car's worn-out lead-acid battery costs more than a new gasoline-powered car. Most of today's electric cars are still propelled by lead-acid batteries. General Motors in their prototype Impact, for example, used starting-lighting-ignition batteries, which deliver lots of power for demonstrations, but have a life of less than 100 deep discharges. Now promising alternative technology has challenged the world-wide lead miners, refiners, and battery makers into forming a consortium that sponsors research into making better lead-acid batteries. Horizon's new bipolar battery delivered 50 watt-hours per kg (Wh/kg), compared with 20 for ordinary transport-vehicle batteries. The alternatives are delivering from 80 Wh/kg (nickel-metal hydride) up to 200 Wh/kg (zinc-bromine). A Fiat Panda traveled 260 km on a single charge of its zinc-bromine battery. A German 3.5-ton postal truck traveled 300 km with a single charge in its 650-kg (146 Wh/kg) zinc-air battery. Its top speed was 110 km per hour     

Applications of aluminum-air batteries

Advances in aluminum-air batteries are described. These include alloys that show higher efficiencies and therefore lower hydrogen evolution, low-cost air cathodes that can be fabricated in production quantities, and methods for handling the aluminum hydroxide reaction product. Emphasis is placed on the advances in air cathodes. The application of this technology to new products and the implications for electric vehicles are discussed     

Industrial battery technologies and markets

Industrial battery market segments generally fall into two major categories--traction batteries, also called motive power batteries; and stationary batteries, also referred to as standby power batteries. The major industrial battery subcategories are discussed. Industrial trucks and rail and mine vehicles represent two major subcategories of motive power batteries. Industrial trucks include forklifts, automated guided vehicles (AGVs), various types of towing vehicles, floor cleaning equipment and so forth. Battery-powered rail and mine vehicles are used in mines where gas is present that could be ignited by spark ignition engines. Locomotive starting batteries and railcar emergency power batteries are also included in the second subcategory. The distinction is beginning to blur between valve-regulated industrial batteries and golf cart or marine batteries. Both industrial and SLI(starting/lighting/ignition)-derivative batteries are competing for markets in the future. The future trends in industrial battery production in Japan, USA and Europe are discussed     

View from the outside, at ISATA

The author discusses measures which can reduce petroleum consumption and reduce pollution. The topics discussed include: hybrid car propulsion; use of carbon-composite structures; electric vehicles production; and system engineering solutions     

Electric car progress

Our global temperature's rise is caused by our atmosphere's ever-increasing content of carbon-dioxide, most of which comes from the exhaust of transportation vehicles. This has resulted in a worldwide search for alternatives to the high-powered gasoline fueled automobiles in wide use today. Replacing gasoline-powered cars with electric and hybrid-electric vehicles has become the most popular tool for reducing carbon-dioxide emissions into our atmosphere. Evaluation of electric alternatives to gasoline-engine propulsion of cars covers such topics as the efficiency, weight, and lifetime of fuel cells, and increasing the charge/discharge life of the new lightweight lithium and nickel metal-hydride batteries. A summary of the work currently being carried out on battery and hybrid vehicles is included here     

Hybrid electric vehicles: year 2000 status

In the year 2000, the automotive manufacturers turned their attention to Hybrid Electric Vehicles (HEV). This re-direction of Electric Vehicle (EV) development effort was highlighted at the North American International Auto Show (NAIAS 2000), where, the World's major automobile manufacturers displayed twenty three HEVs. Thirteen HEV were configured with an internal combustion piston engine and electric traction motor, while, ten additional HEV were configured as fuel cell and battery pack hybrid vehicles (FCHV). Furthermore, the FCHV were fueled with hydrogen (H₂) from H₂ absorption metal hydride fuel tanks, or, from liquified hydrogen cryogenic fuel tanks. One conclusion for HEV was that the preferred configuration includes a compression ignition engine paired with an electric motor, and, four speed manual transmission with automatic shift. A second conclusion for FCHV was that the fuel of choice is H₂, and furthermore, these H₂ fueled FCHV were the precursor vehicles foreshadowing deployment of a hydrogen fuel infrastructure within the first quarter of the 21^st Century     

小型和微型无人机的气动特点和设计

讨论了当前包括固定翼、扑翼和微型旋翼的小型无人驾驶飞行器(SUAV)和微型无人驾驶飞行器(MAV)的进展和未来发展可能涉及的技术问题。讨论了低雷诺数空气动力特性,包括分离气泡和展弦比的影响。介绍了用于拍动翼的非定常空气动力特性和高升力机理。讨论了目前存在的2种设计方法——多学科/多目标优化设计和探索式/进化式的设计方法,以及在设计中柔性翼和主动智能控制的重要性。     

富锂锰基正极材料研究进展

随着社会发展,电动汽车、消费类(3C)电子产品、储能装置等对锂离子电池的能量密度提出了更高要求。富锂锰基正极材料具有高比容量(≈250 mAh/g)、高工作电压(≈3.6 V)及低成本等优势,有望成为下一代商用高比能电池正极材料。首次库仑效率低、倍率性能差、电压/容量衰减快等问题限制了富锂锰基正极材料的工程化应用。本文综述了富锂锰基正极材料的最新研究进展,重点从材料结构、电化学反应机理、失效机制和改性方法等几方面进行了阐述。研究表明,采用离子掺杂、表面包覆、晶体结构调控等技术,可显著改善富锂锰基正极材料的电化学性能。最后,对富锂锰基正极材料的发展方向进行了展望。     

可重复使用热防护材料应用与研究进展

可重复使用热防护系统是为高速重复使用飞行器而发展的关键性技术,涵盖了地球大气环境及非地球大气环境下的弹道式再入、高马赫数巡航等应用场景。根据现有高马赫数飞行器热防护现状,对高马赫数飞行器的主要热防护系统类型、特点和使用场景进行了简要介绍。在此基础上,结合国外里程碑式可重复使用飞行器（X-15、SR-71、航天飞机、X-33、X-37B、Spaceliner等）,梳理了可重复使用热防护材料的应用与研究进展,论述了代表性可重复使用热防护材料的发展、性能、研制进度、特点及应用前景。对国外在可重复使用热防护材料研制中的设计及发展思路,以及所存在的主要问题进行了总结归纳,为可重复使用热防护材料未来的发展提供了思路。