Advanced Architecture and Design of Computer

Electric Cars

Abstract

This paper has been written to provide a comprehensive picture of electric cars by introducing the history, current status and the likely future development of electric cars. The paper also focuses on the batteries that are used to charge these electric cars, since it's considered the core component of such cars and the main factor of electric car's efficiency. In addition, the paper discusses other issues related to these electric cars such as: types of electric vehicles, comparison between gasoline and electric cars, disadvantages of electric cars and the effect of electric cars on the environment.

1. INTRODUCTION

Electric cars are classified under the electric vehicles (EVs) category, and you may be wondering what exactly an EV is. An EV can be simply defined as any form of transportation that depends on electricity as the main source of power for its motor that makes the vehicle move. This definition includes a wide variety of electric vehicle examples such as trolleys, golf carts, forklifts, and even your remote control car. Although the term EV covers a wide variety of vehicles, this paper focuses on electric cars used by ordinary citizens. You might also be wondering about the difference between batteries-powered and a gas-powered car, the basic difference is that an electric car uses an electric motor instead of an engine and a set of batteries instead of a gas tank.

2. WHAT IS AN ELECTRIC CAR?

An electric car is a car that its power is generated by an electric motor instead of a gasoline engine. The electric motor receives its energy from a controller, and based on the driver's use of an accelerator pedal the controller controls the amount of power generated for the electric motor. The electric car, which is also known as an EV, uses the energy stored in its rechargeable batteries which can be recharged by common household electricity, or other source onboard the vehicle, or from an external source in, on, or above the roadway [1].

The name "electric car" is often used to refer to electric vehicles that use batteries as the sole source of electric power. If the power source for an electric car is not explicitly an on-board battery, the electric car is generally referred to by a different name depending on the source of energy for its motors. For example, an electric car which uses the sunlight to power its motor is called a "solar car", or an electric car powered by a gasoline generator is a form of hybrid car [3].

3. HISTORY

The history of electric cars is in fact the story of how the progress of practical methods of storing electrical energy combined with the invention of methods of converting electrical to mechanical energy offered for the world environment and population the possibility of new, clean, and quiet methods of propulsion [2].

3.1 1830s to 1900s: Early Start

Electricity has been used since many years ago as one of the methods for automobile propulsion and still in use today, it predates the invention of Diesel's and Benz's Otto cycle-engines by several decades. Many people contributed to the invention of the electric vehicles. In 1828, Anyos Jedlik from Hungary worked to invent an early type of electric motor and used this motor to power a tiny model car as can be seen in figure-1. In 1834, Vermont Blacksmith installed the first American DC electrical motor which he has invented in a small model car and tested it on a short circular electrified track. In 1835, Professor Sibrandus Stratingh used non-rechargeable primary cells to power a small-scale electrical car. In 1838, an electric locomotive was built by Scotsman Davidson, it attained a speed of 6.4km/h. In the time between 1832 and 1839, a crude electrical carriage was invented by Robert Anderson from Scotland. The invention of improved battery technology in 1881 paved the way for electric cars to flourish in Europe [4].

3.2 1920s to 1980s: Domination of Gasoline

After the great success that electric cars achieved at the earlier time of the century, the electric cars started to loose its reputation and position in the automobile market. Its position was replaced by a number of developments. Firstly, the improvement of road infrastructure between American cities in 1920s encouraged the production of vehicles that can be used for greater range than the electric cars can reach. Secondly, the discovery of large wells of petroleum in Texas, Oklahoma, and California offered a wide availability of gasoline; this made the gas-powered cars less costly to drive over long distances. At that time gasoline-powered cars were able to travel longer distances at faster speeds than equivalent electric cars which were limited to urban use with limited speed and range. Thirdly, the invention of the electric starter by Charles Ketteing in 1912 offered a very easy use of gasoline cars since it eliminated the need of a hand crank for starting the gasoline engine. Finally, the initiation of mass production reduced the cost of gasoline powered cars to approximately half the price of its equivalent electric cars. After that, a number of years passed without any major revival in the development and use of electric cars [4].

3.3 1990s to present: Revival of electric cars again

"After years outside the limelight, the energy crises of the 1970s and 80s brought about renewed interest in the perceived independence electric cars had from the fluctuations of the hydrocarbon energy market" [4]. In the early 1990s, California Air Resources Board (CARB), started a push for electric vehicles as an ultimate solution for zero-emissions and environmentally friendly vehicles. In response to this push, automakers began to develop electric models including the Chrysler TEVan, GM EV1 and S10 EV pickup, Honda EV Plus hatchback, Nissan lithium-battery Altra EV miniwagon ,Ford Ranger EV pickup truck, and Toyota RAV4 EV. The automakers were forced to response to the requests of CARB in order to continue to be allowed to sell cars in the Californian market. But the public interests continued to choose the fuel-powered cars over the electric powered cars which caused the withdrawal of a large amount of electric cars production from the market and this also forced some manufacturers to destroy their cars

After that, American automakers decided to concentrate their product lines within the truck-based vehicles category, which were able to target higher profit margins than the smaller cars which were more preferable in areas like Europe or Japan. In 1999, North America was the first place to release the first hybrid car which was Honda Insight hybrid car since the little-known Woods hybrid of 1917, which featured a combined gasoline and electric power-train, were seen as a balance, offering an environment friendly image and progressed fuel economy, without being affected by the low range of electric vehicles, although with a higher cost than comparable gasoline cars. Sales were poor; the lack of interest was due to the car's small size and the lack of necessity for a fuel-efficient car at the time. The 2000s energy crisis brought renewed interest in hybrid and electric cars. In America, sales of the Toyota Prius (which had started to be on sale since 1999 in some markets) increased considerably, and a variety of automakers followed suit, building and developing hybrid models of their own. A large number of automakers were encouraged and started to produce new electric car prototypes, responding to consumers' interest and seeking for cars that do not get affected by the fluctuations of oil prices.

In 2004, the United States were having about 56,000 low-speed, battery powered vehicles in use, this number continued to increase considerably to reach about 76,000 vehicles in July 2006. In 2009, Mitsubishi Motors and PSA Peugeot Citron announced a joint venture to develop electric vehicle technology. Nowadays, a large number of electric vehicles is designed, manufactured and released in the market by different manufacturers [5].

4. TYPES OF ELECTRIC VEHICLES:

Electric vehicles can be divided into three main types:

Battery electric vehicles (BEVs): are vehicles which depend on the electricity stored in large batteries inside the vehicle as the sole source for power. The battery powers an electric motor, or motors, which then does its role of driving the vehicle. The batteries need to be recharged on regular basis by plugging into recharging points such as the mains electricity supply.

Hybrid electric vehicles (HEVs): are vehicles that are powered from two combined sources; electricity stored in batteries and either a petrol or diesel internal combustion engine. The most interesting thing about the hybrid vehicle is that it does not need to be plugged in to recharge its battery, as this its batteries are recharged automatically as the vehicle is being driven.

Plug-in hybrid electric vehicles (PHEVs) work similarly to conventional hybrids in that they operate using the vehicle's petrol or diesel engine or by using electricity to power an onboard electric motor. However, PHEVs have much larger batteries than conventional HEVs and so can also be charged from the mains when not in use - hence 'plug-in' - and this means the vehicle can cover a greater distance. There are two key types of PHEV:

o The first can run indefinitely with the petrol/diesel motor providing power as in a normal car.

o The second is effectively a battery-powered vehicle with a small onboard generator to extend the distance the car can travel.

Most new electric vehicles also use an advanced braking system known as 'regenerative braking' that allows the electric motor to re-capture the energy expended during braking that would normally be lost. This improves energy efficiency and reduces wear on the brakes.

5. COMPARISON BETWEEN GASOLINE AND ELECTRIC CARS

In fact, if you look at the two types of vehicles, electric and gasoline powered, you will not be able to identify any difference in the outside shape except that the electric vehicle does not have a tail pipe. But internally, it is completely a different look. According to the advanced transportation consortium in California, the difference in the vehicle's component parts between the electric and gasoline powered vehicles might reach up to 70% difference. The electric vehicle has more several unique components that serve the same function as the more common components in a gasoline-powered vehicle. There is also another significant difference between electric vehicles and gasoline-powered vehicles which is the total number of moving parts. An electric vehicle has only one moving part which is the motor, on the other hand a gasoline-powered vehicle can have hundreds of moving parts. Fewer number of moving parts in the electric vehicle leads to another important difference. The electric vehicle does not need regular maintenance and is more reliable. The gasoline-powered vehicle requires a wide range of maintenance, from frequent oil changes, filter replacements, periodic tune ups, and exhaust system repairs, to the less frequent component replacement, such as the water pump, fuel pump, alternator, etc. The electric vehicle's maintenance requirements are fewer and therefore the maintenance costs are lower. The electric motor has one moving part, the shaft, which is very reliable and requires little or no maintenance. The controller and charger are electronic devices with no moving parts, and they require little or no maintenance. State-of-the-art lead acid batteries used in current electric vehicles are sealed and are maintenance free. However, the life time of these batteries is very short and this requires that the batteries need to be replaced periodically. New batteries are being developed that will not only extend the range of electric vehicles, but will also extend the life of the battery pack which may eliminate the need to replace the battery pack during the life of the vehicle. Not only are electric vehicles easier and cheaper to maintain, they are also more efficient than the gasoline engine and are therefore cheaper to operate [8]. Figure-2 shows a comparison between electric and gasoline cars.

6. BATTERIES FOR ELECTRIC CARS

The performance and cost of batteries is one of the biggest potential obstacles to the success of EVs, as it defines the electric range, performance characteristics and costs. Lithium-ion batteries seem to be the most powerful battery type among the battery-types, although no studies expect their costs to reduce rapidly. . Studies and articles all agree that the widespread roll-out of electric vehicles (EVs) and plug-in electric hybrids (PHEVs) will depend on advances in battery technology, principally improvements in cost, performance and safety. Meanwhile, interest in developing batteries for cars is very high within industry, as the worldwide market for hybrid electric vehicles is expected to more than triple by 2015, to 2.3 billion USD as mentioned in [7].

6.1 Different kinds of batteries

It is a major technical challenge to produce batteries able to store large amounts of energy that can be released and recharged quickly. There are two kinds of battery: a standard battery allows a lot of energy to be stored, but the energy can be released or recharged only slowly; and a super-capacitor, which stores a limited amount of energy at the surface of the electrode and is quick to charge and discharge. A battery that can both store a lot of energy and discharge it rapidly is essential for electric cars [7].

6.1.1 Lead acid

First release of lead-acid batteries was in 1859, it was used in the first electric cars. Nowadays, lead-acid batteries make up about half of the worldwide rechargeable battery market. Small-sized lead-acid battery packs provide short bursts of power to starter motors in virtually all cars and they are also used in large back-up power systems. However, it is not expected that this technology would improve to the level to be used in PHEVs and EVs [7].

6.1.2 Nickel cadmium

Nickel-cadmium batteries were introduced around 1900 and used specifically in cases where a larger amount of power is needed to operate a system or a device. These batteries provide emergency backup power on planes and trains. For most of the 20th century lead-acid and nickel-cadmium cells dominated the rechargeable battery market, and both are still in use today. However, the toxicity of cadmium, plus the fact that the batteries store relatively limited energy for a given weight or volume, compared to newer technologies, undermines their potential [7].

6.1.3 Sodium nickel chloride

Sodium nickel-chloride (ZEBRA) batteries have mainly been tested for heavy duty vehicles and are characterized by their long lifetime and relative high-energy density at low costs. However, they do not meet the power requirements of EVs and HEVs, and are therefore only produced in low volumes [7].

6.1.4 Nickel-metal hydride

Nickel-metal-hydride (NiMH) batteries evolved from the nickel-hydrogen batteries used to power satellites. They are expensive and bulky, but do offer high energy-density and last a long time. Nickel-metal-hydride batteries have been adapted for use in cars, and are expected to work for eight to 10 years. They must endure hundreds of thousands of partial charge and discharge cycles as they absorb energy from regenerative braking, or supply short bursts of power to aid in acceleration [7].

6.2 Electric car battery testing study [10]

This section discusses an example of a study that has been done on electric car batteries testing. An electric utility company was interested in using electric vehicles for its meter readers and other customer service personnel. In order to determine the feasibility of this idea, engineers needed to evaluate the vehicle's operating parameters during operation and measure what effect they would have on its electrical requirements. In other words, they needed to determine how long the batteries would be able to power the vehicle under normal operating conditions.

6.2.1 Study summary

After an electrical propulsion system was installed in a small pickup truck; the engineers began to research methods for increasing the truck's operating efficiency and its operating range between battery charges. Some initial possibilities they considered were: solar panels to extend the battery life, regenerative braking to recover kinetic energy, lighter plastic components replacing the heavier stock vehicle components, and low resistance tires. All of these methods would extend the range of the vehicle; however, the relative merits of each needed to be quantified so that the value of each modification in terms of performance could be compared to the cost of its implementation. To obtain this data, the vehicle's operation needed to be measured both before and after each modification.

To make the measurements, the researchers needed a data acquisition system able to meet a demanding set of performance criteria. These criteria included portability, operability from a battery, ability to accommodate mixed analogue signals, a high channel count, and expandability. The system needed to run unattended after a relatively simple setup procedure. Furthermore, the system's sampling rate, resolution, accuracy, and data transfer speed needed to be sufficient.

6.2.2 IOtech's Solution

The data acquisition system that best met these criteria was IOtech's PC-based DaqBook data acquisition system. The DaqBook system was equipped with IOtech's thermocouple card and universal voltage and current card. The thermocouple card provided auto zero, cold-junction compensation, and programmable gain for a variety of temperature measurements. The signal conditioning card accommodated analog signals from transducers placed on the vehicle to measure voltage, current, temperature, and other variables. The data acquisition was controlled by a notebook PC using a custom software program; the PC's hard drive provided data storage. The DaqBook data acquisition system provided the accuracy needed to capture even the most rapidly changing variables. It also provided sufficient channels in the form of 8 differential or 16 single-ended analogue inputs, plus many additional output and digital input channels. Expandable to 256 analogue-input channels, the DaqBook system was capable of multiplexing all channels with individual gains for each channel. The DaqBook's rugged metal enclosure is roughly the same form factor (8 1/2" x 11" x 1 3/8") as the notebook PC, as is the optional expansion card enclosure and battery pack. The system was installed behind the driver's seat, and combined with the PC, weighed no more than 35 pounds, of which 15 pounds was mounting hardware.

6.2.3 Data acquisition system measurements

Battery charge and discharge characteristics were perhaps the most important variables measured on the electric vehicle, which used 20 six-volt lead/acid batteries connected in series to drive a 120 VDC motor. A voltage divider was used to scale down the aggregate voltage to 5 VDC for input into the data acquisition system. A clamp-on current sensor measured battery charge and discharge current, up to a maximum of 400A. The sensor output was set up for 5 VDC for 500A full-scale current flow in either direction. Voltage and current were also measured on a 12 VDC accessory battery used to operate windshield wipers and lights. To help determine the effects of charge and discharge characteristics on the batteries, temperatures were measured in various locations. Thermocouple probes were installed in selected cells to measure electrolyte temperatures inside the front and rear battery assemblies. Flush mount thermocouples measured the batteries' casing temperatures. Other temperature measurements included a flush mount thermocouple on the drive motor, and a thermocouple probe in the bed of the truck for ambient air temperature. Charge/discharge data was correlated with truck loading. Although the truck load itself was virtually constant, terrain affected both motor load and speed. Terrain was measured with an inclinometer installed behind the truck's seat in the centre of the cab. The output was scaled 0 to 3.6 VDC for 0 to 360 of rotation (incline). Vehicle speed was measured by attaching a pulse generator to the speedometer cable. The DaqBook data acquisition system's counter timer created the appropriate speed scale. The output from an electronic tachometer connected to the motor was used in a similar fashion to obtain motor speed.

6.2.4 Conclusion of this study

Using a single portable PC-based data acquisition system, the researchers were able acquire many channels of data of mixed signal types in a very easy and quick way. IOtech's DaqBook data acquisition system worked so well that the utility is considering alternative uses for it.

6.3 FUTURE IDEAS FOR BATTERY TESTING APPLICATIONS

One possible future application for electric cars battery level testing is to add a Global Positioning Satellite (GPS) system that would determine the vehicle's coordinates and those of its proposed destination. This information, combined with terrain data and battery-charge data, would allow the driver to decide whether the truck could make a trip of a certain distance on its current charge. Also, this application could be further improved so that when a car is forced to stop some where because of the complete loss of its charging it can send a help request signal to a server station that can determine the electric car position by the sent coordinates and send a charging help to that stuck electric car.

7. DISADVANTAGES OF ELECTRIC CARS

Although the electric vehicle will be less costly to operate and maintain, a number of challenges still exist for the owner of an electric vehicle.

First and foremost challenge is the limited range available with current battery technologies. The driving range between recharging using existing batteries is between 50 to 150 miles. New battery systems are being developed that will increase this range, and prototypes of these batteries have demonstrated ranges up to 200 miles between recharging.

The second challenge is the infrastructure to recharge the batteries, which is a very important issue. The most significant element of the recharging infrastructure already exists: electric power is available in almost all locations. The remaining element needed is to ensure that charging stations, with the proper types of service (i.e., maximum voltage and current), are available at strategic locations to support the electric vehicle. Arrangements must also be made to ensure off-peak charging to get the lowest utility rates.

The third challenge is that EVs contribute to higher emissions elsewhere. Although electric-powered vehicles create zero or fewer emissions than petrol or diesel cars when in use, there are emissions released when the any mains electricity used is actually being produced. These emissions should be taken into account when assessing the net environmental benefits of EVs. If renewable energy is used to generate the electricity then the impact on the environment is much less than other vehicle technologies. If nonrenewable energy is used, then the environmental benefits are reduced. In addition, hybrid electric vehicles cause greater pollution during manufacture and disposal than conventional vehicles [8] [9].

8. ELECTRIC CARS ARE NOT AS GREEN AS YOU THINK

The consideration of pollution is important. The dominant form of electricity generation in the United States is the burning of coal. Thus, an electric car shifts the pollution from the vehicle to the coal plant. That is an excellent factor for congested smog saturated areas. The coal plants operate at respectable efficiencies and have means to minimize pollution far better than what is practical for a gasoline vehicle. The only other option is nuclear as hydro-electric and other nature driven systems are limited in what they can produce. Thus, shifting to electric cars would result in a net reduction in pollution.

CONCLUSION:

The shift to electric cars is best done via natural growing cost disadvantages for gasoline and improving cost advantages for electric with advances in technology. Considering the benefits of reduced air, water, noise and thermal pollution and reduced greenhouse gas emissions, accommodating the modest increase in electrical demand is a challenge we should welcome. Further evaluation of the environmental impacts of battery disposal and recycling is required, and data on the energy consumption of battery production and recycling is lacking. Electric car battery level estimation researches and studies can open the doors for many future possibilities and applications depending on the data obtained from studying and estimating the electric car battery level.

REFERENCES

[1] " Electric cars: a definitive guide", [cited 2009 Dec 29], Available HTTP: http://www.hybridcars.com/electric-car

[2] M. Westbrook," The electric car: development and future of battery, hybrid and fuel-cell cars," IEE Power & Energy Series 38. UK, 2005, pp.6-28.

[3] "Electric automobile", [cited 2009 Dec 29], available HTTP: http://www.britannica.com/

[4] B. Ferrel," History of the electric car: 11828-1912, from Trouve to Morrison",[cited 2009 Dec 30], available HTTP: http://factoidz.com/history-of-the-electric-car-1828-1912-from-trouve-to-morrison/

[5] J. Saranow, "The electric car gets some muscle",2006, The Wall Street Journal, [cited 2009 Dec 30], available HTTP: http://www.post-gazette.com/pg/06208/709068-185.stm

[6] K. Kuhn, "An Economic Comparison between Gasoline and Electric Cars", 2008.

[7] European Federation for Transport and Environment AISBL, "Electric cars: from hype to reality", November 2009.

[8] "How Do Gasoline & Electric Vehicles Compare?", [online document], [cited 2010 Jan 1], available HTTP: avt.inel.gov/pdf/fsev/compare.pdf

[9] "Hybrid Electric and Battery Electric Vehicles", Buyer guide, Sustainable energy Ireland.

[10] "Electric Car Battery Testing - using DaqBook", [online document], [cited 2010 Jan 4], available HTTP: http://www.iotech.com/appnotes/an30.aspx

[11] Rembrandet, "Cost and environment impact of electric cars", February 2009.

[12] "Electric Car: American Industry and Innovation", the Gov, 2009.

[13] "Electric cars rolling out", 16 December 2009, [cited 2010 Jan 5], available HTTP: www.physorg.com/news180171314.html

[14] "New Battery For Electric Cars", May 2006, U.S. Patent.

Please be aware that the free essay that you were just reading was not written by us. This essay, and all of the others available to view on the website, were provided to us by students in exchange for services that we offer. This relationship helps our students to get an even better deal while also contributing to the biggest free essay resource in the UK!