Electric Cars Presentation

Electric Cars Andrew D. Bushner Engineering 223A Electric Circuits Lab

Thesis  One

of the greatest engineering marvels that are becoming more and more popular today is the electric car, which has come a long way since they were first introduced in 1828.

What will be covered  History

of the electric car

 When

electric cars were first introduced  History to modern day 

How today’s electric cars work  Electric

motors and batteries  Charging 

Challenges with electric cars today

History  1828 

Ányos Jedlik invented an early type of electric motor that powered a tiny model car

 1839 

Robert Anderson invented the first electric vehicle that was powered by nonrechargeable primary cells

 1859 

Gaston Planté invented the rechargeable lead-acid storage battery, improved a few years later by Camille Faure

 1891 

William Morrison of Des Moines, Iowa built the first successful electric automobile in the United States  24

battery cells  4-horsepower  Top speed of 20 mph  Range of about 50 miles

 1897 



Electric Vehicle Company introduced electric taxicabs to New York City that could be driven about 50 miles on one charge By 1899 the city had more than 60 electric taxicabs



1900  

More than four thousand were cars on the road, electric cars made up about one third of them Electric cars had advantages over the other cars of its time Quicker to start up than the steam-powered cars  Ran cleaner than the internal combustion engines  Did better in the snow 

 1908 

 

Henry Ford introduced the Model T which cost only $850 compared to the average price of an electric car of about $2000 Model T’s had a better production method and eventually overtook electric cars Four years later, Charles Kettering invented the first practical electric automobile starter, making gasoline-powered cars even more practical



1920 

Electric cars ceased to be a viable commercial product 

  

 

Roads were more developed Consumers wanted to travel further Gasoline was inexpensive Electricity was not as readily available as gasoline

Electric cars became impractical and, by the late 1920s, were nearly gone from the market From the mid-1920s to the early 1990s, there was little large-scale production of electric cars

 1966 

Congress introduced an early bill that recommended the use of electric vehicles as a means of reducing air pollution

 1970s 

Concerns over soaring price of oil and the growing environmental movement resulted in renewed interest in electric cars

 1988 



Roger Smith, CEO of G.M., funded research to build a practical consumer electric car G.M. teamed up with California's AeroVironment to design the EV1

 Late 

A

1990s and early 2000s

G.M. unveiled the EV1 in 1996 which traveled 80 miles per charge

few thousand all-electric cars from big car manufacturers were produced, but most of them were available for lease only

 2003 

 

G.M. announced it would not renew leases on its EV1 cars saying that they can no longer supply parts to repair the vehicles By 2005, all the EV1s were collected and “recycled” The car was the subject of the 2006 film "Who Killed the Electric Car?" where General Motors spokesman stated that the EV1s were to be recycled, not just crushed

 2006 

Tesla Motors unveiled the Tesla Roadster which brought luxury to the electric car market  The

Tesla Roadster was priced over $100,000  They were meant for a high-income market and aimed to show off what an electric engine could accomplish  The car had 300 HP, 295 ft-lb of torque, 3phase 4-pole AC induction motor, and a 53 kWh Lithium-ion battery  Almost 250 mile range  Can accelerate from 0 to 60 mph in 3.7 seconds

 2010 

to present

Nissan released its new electric car called the LEAF (Leading, Environmentally friendly, Affordable, Family car)  Maximum

speed of 90 mph  Can travel 100 miles on a full charge  Capable of being recharged to 80% of battery capacity in 30 minutes 

Several new electric cars, including the BMW Mini E and Mitsubishi i-MiEV, have been produced and sold with a reported 3.8 million to be on the roads worldwide by 2016

Electric Motors 

 

Electric motors get their power from a controller, and the controller gets its power from rechargeable batteries The motor's controller is what takes the power from the batteries and delivers it to the motor The accelerator pedal is hooked up to a pair of potentiometers, which are variable resistors, and these potentiometers provide the signal that tells the controller how much power it is supposed to deliver

DC controller connected to batteries and a DC motor •

•

•

The DC controller reads the setting of the accelerator pedal from the potentiometers and regulates the power accordingly If the accelerator is pushed halfway down, the controller reads that setting from the potentiometer and rapidly switches the power to the motor on and off so that it is on half the time and off half the time If the accelerator is pushed onefourth of the way down, then the controller pulses the power so it is on one-fourth of the time and off three-fourths of the time

AC controller connected to AC motor •

•

• •

An AC controller creates three pseudo-sine waves by taking the DC voltage from the batteries and pulsing it on and off In an AC controller, there is the additional need to reverse the polarity of the voltage 60 times a second AC controllers need six sets of transistors For each of the three phases, one set of transistors is needed to pulse the voltage and another set to reverse the polarity so six transistors are needed

DC vs. AC motors  

Electric cars can have two different types of electric motors: a DC motor or an AC motor If the motor is a DC motor:    



It runs on voltage ranging from 96 to 192 volts They are more affordable and easier to control They have greater initial torque and higher peak power However, they have a tendency to overheat and become very large and heavy according to their power output

If the motor is an AC motor:    

 

They are a three-phase AC motor running at 240 volts AC with a 300 volt battery pack They are better for continuous power, which helps with climbing hills but starting power is slower They run at high RPM without overheating and because of this, they do not require a transmission They are best suited for regenerative braking systems, which is a feature present on many electric vehicles that recovers approximately 20% of the energy usually lost in the brakes to recharge the battery They run more smoothly and can be precisely controlled Conversely, they are more expensive and require a converter, so they take up a lot of space

Batteries  





There are three types of batteries found in electric cars: lead-acid batteries, nickel-metal hydride batteries, and lithium ion batteries Lead-acid batteries:  Are the cheapest and most common batteries available  Do not last long and typically need replacement every 3 years  End up being a significant portion of the final weight of the vehicle  Efficiency and storage capacity decreases with lower temperatures, and diverting power to run a heating coil reduces efficiency and range by up to 40% Nickel-metal hydride batteries:  Have an energy density higher than lead-acid  Have exceptionally long lives, being known to still operate well after 100,000 miles and over a decade of use  Are less efficient in charging and discharging than lead-acid batteries  Tend to have the poor efficiency, high self-discharge, finicky charge cycles, and poor performance in cold weather Lithium ion batteries:  Are considered to have the most potential for mass-market electric vehicles  Have a very high energy density, good power density, and 80 to 90% charge/discharge efficiency.  Have short cycle lives, usually few thousand charge cycles, and significant degradation with age  Are somewhat toxic and can pose a fire risk if punctured or charged improperly  Do not accept or supply power in cold conditions so expensive and energy inefficient systems are necessary to warm them up

Charging  



 

Chargers monitor current and make assumptions about average battery characteristics The chargers apply maximum current to the batteries up through eighty percent of their capacity, and drop the current back to a preset level for the final twenty percent to avoid overheating the battery Normal household 120-volt outlets typically have a 15-amp circuit breaker, meaning that the maximum amount of energy that the car can consume is approximately 1.5 kilowatt-hours per hour Most batteries need anywhere from 12 to 18 kilowatt-hours for a full recharge, so it can take over eight hours to fully charge the vehicle However, by using a 240-volt circuit, like an outlet for an electric dryer, the car will receive 240 volts at 30 amps, or 6.6 kilowatt-hours per hour, allowing significantly faster charging with a full recharge in about four to five hours

Problems  Batteries  

Heavy and take up a lot of space Need to be recharged  Charging

stations are a rarity in most cities  Take a long time to recharge  Need to replaced somewhat frequently  Range  Price

Resources  http://auto.howstuffworks.com/electric-

car2.htm  http://www.futurecars.com/futurecars/ele ctric_cars1.html  http://www.npr.org/2011/11/21/14236534 6/timeline-the-100-year-history-of-theelectric-car  http://www.vehix.com/articles/autopreviews--trends/electric-cars-a-briefoverview

Questions?