The Science of Electric Vehicles

Size: px

Start display at page:

Download "The Science of Electric Vehicles"

Edward Miller
5 years ago
Views:

1 The Science of Electric Vehicles Alan Soule and Chris Jones North Bay Electric Auto Association Presentation to Science Buzz Café French Garden Restaurant, Sebastopol July 22, :30 PM This presentation is posted at

2 Alan Soule NBEAA PR Director Tesla Roadster owner Chris Jones NBEAA President Mustang EV Converter

3 Agenda Reasons to Drive an EV EV Components Buying an EV Driving an EV The Tesla Roadster EV Show and Tell

4 Reasons to Drive an EV Energy Independence 60% of 2006 US oil consumption was imported per the US Government Energy Information Administration Basic Petroleum Statistics, Greenhouse Gas Reduction Transportation accounted for 42% of greenhouse gas emissions in Sonoma County in 2000, according to the Climate Protection Campaign s January 2005 report Greenhouse Gas Emission Inventory for all sectors of Sonoma County, California, Air and Water Pollution Reduction Asthma cost $12.7B in 1998 and can be caused by vehicle exhaust, per the Center for Disease Control Asthma Speaker s Kit, See for more frequently asked EV questions.

5 Energy Independence 100% Non- Renewable Energy Consumed: 71% 24% 0% Efficiency: Petrol ICE EVs charged by ICE grid EVs offset by PVs made by ICE grid EVs offset by PVs made by PV grid Combustion 15% 35% 35% n/a Grid n/a 90% 90% 90% Energy Generation n/a n/a 300% 300% Charger n/a 90% 90% 90% Battery n/a 90% 90% 90% AC Drive System n/a 85% 85% 85% TOTAL 15% 21% 63% Infinite for 5.5B years Efficiency of fuel input to motor shaft output only. Energy to make EV can be higher, but it makes up a small amount of the total energy consumed from cradle to grave of an ICE. Emissions vary based on type of fuel used to power the grid.

6 Greenhouse Gas Reduction

7 Cost The great news: EVs cost far less to operate. Tesla Roadster: 71% less gas (Lotus Elise): $3 per gallon / 22 MPG = $.14 per mile electric: $.12 per kwh / 3.5 miles per kwh = $.04 per mile Mustang Conversion: 60% less gas: $3 per gallon / 20 MPG = $.15 per mile electric: $.12 per kwh / 2.0 miles per kwh = $.06 per mile Note: charging at peak rate is more, but less with an E9 Time of Use PG&E meter, solar, or free work or public charging.

8 Cost The bad news: EVs can cost more to own overall if you purchase or convert one with advanced technology, and gas prices remain low. The following examples for our vehicles assume car is scrapped in 10 years, the batteries deliver enough power and capacity for the life of the car, there is no significant difference in maintenance cost, and gas prices do not increase. Tesla Gas (Lotus Elise) electric Car purchase $60,000 $109,000 Fuel to travel 150K miles 41 miles per day 18% DOD $21,000 $6,000 Total $81,950 $115,000 $33,050 more $9.05 more per day: 3 medium Peet s lattes Mustang Gas electric Car purchase $10,000 $10,000 donor car $30,000 EV conversion Fuel to travel 73K miles 20 miles per day 50% DOD $10,950 $4,380 Total $20,950 $44,380 $23,430 more $6.42 more per day: 2 medium Peet s lattes

9 Cost The good news: EVs will cost less to own if EV prices come down, or if EV incentives or gas prices go up. The following example for the Nissan Leaf assumes car is delivered as announced, is scrapped in 10 years, the batteries deliver enough power and capacity for the life of the car, there is no significant difference in maintenance cost, and gas prices do not increase. Leaf Gas (Versa hatchback) electric Car purchase $15,000 $25,000 after federal rebate Fuel to travel 150K miles 41 miles per day 18% DOD $16,071 at 28 MPG $6,000 Total $31,107 $31,000 $107 more $.03 more per day: same cost at $3 per gallon

10 EV Components Motor Batteries and Electronics

11 2-Pole Series Wound DC Motor Demonstration Field Windings Armature Windings Commutator Brush Current flows through the brushes, commutator, armature windings and field windings to create electromagnetic forces that oppose each other, which causes the armature to turn.

12 Electric Motor Types type brushes Stator (stationary part) Rotor (rotating part) DC Series Yes Field windings Armature windings, commutated through brushes and split rings, in series with field DC Shunt Yes Field windings Armature windings, commutated through brushes, separately excited from field DC Brushed Permanent Magnet Yes Field permanent magnet Armature windings, commutated through brushes DC Brushless Permanent Magnet No Armature windings, PWM d via rotor position sensor Field permanent magnet AC Synchronous Yes Armature windings, PWM d via rotor position sensor Field windings, DC energized through brushes and slip rings AC Induction No Armature windings, PWM d via rotor position sensor Opposing magnetic field induced via eddy currents caused by slip between stator and rotor in copper or aluminum squirrel cage frame The field produces a magnetic field to be acted upon by armature; it can be an electromagnet or permanent magnet. The armature carries current normal to field to generate torque.

13 Electric Motor Types

14 Nail / Tube / Salt Water Battery Demonstration

15 Nail / Tube / Salt Water Battery Demonstration A chemical reaction between the zinc nail, salt water and copper tube causes current to flow through the LED, which causes it to light up.

16 Battery Types

batteries Not technically a battery, but MIT Nanotube

17 Batteries in Development Stanford University Silicon Nanowire electrodes have 3X capacity improvement expected for Lithium batteries Not technically a battery, but MIT Nanotube ultracapacitors have very high power, 1M+ cycle energy storage approaching Lithium battery capacity

18 Motor and Battery Charge Control via Pulse Width Modulation 100% duty cycle 75% on off on off 50% on off 25% 0% time on off on off Reducing the duty cycle reduces the power delivered to the load.

19 Switch Mode Power Supply Buck Regulator: a common building block for motor and charge control From power source: batteries, grid or motor in regen mode Filter capacitors From PWM control circuit Freewheel diodes To load: motor or batteries Power switching transistors: MOSFETs or IGBTs When power is applied to input, capacitors are charged up. When transistors are switched on, current flows from the batteries and capacitors to the motor. When the transistors are off, the capacitors are recharged by the batteries while current flows from the motor to the freewheel diodes while the motor s magnetic field collapses to keep from increasing the voltage across the transistor to the point of failure.

20 Buying an EV in the U.S. Refer to Plug In America Plug-in vehicle tracker Currently available EV s in California: Tesla Roadster ($109,000) EV s Scheduled for production: Audi e-tron 2011? BMW ActiveE 2011? CODA 2010 $45,000 Daimler Smart EV 2012? Ford Focus 2011? Hyundai i10 Electric 2012? Mitsubishi imiev 2010 $47,000 Nissan Leaf 2011 $22,000 Peugeot ion 2011? Rolls Royce 2010 ~$500,000 Tesla Model S 2012 $50,000 Toyota Rav4 (Tesla drivetrain) 2012?

21 Driving an EV The process of driving an EV is no different than drive an ICE car High torque for quick acceleration No shifting (no transmission) Regenerative braking monitoring your speed with the gas pedal No loss of Range going up hill, as long as you come down Charging outdoors in the rain is not a problem Accurate metering of charge to monitor how much Range is left HOV exemption for EV s until the end of 2015 Range is the biggest concern Charge at home at night and start out every day with full Range Wind resistance is the biggest factor affecting Range Currently, a trip that requires charging, requires planning because of limited public chargers

22 Tesla Roadster TESLA BATTERY ELECTRICAL CAPACITY: 52.8 KWHR CELL CAPACITY: 7.73 WHR (2.2 AMPHR) QUANTITY OF CELLS: 6,831 CELLS PER BRICK: 69 BRICKS PER MODULE: 9 MODULES PER BATTERY: 11 BATTERY WEIGHT: 970 LB.S (CHARGED OR NOT) ELECTRON CAPACITY: X 10 to the 23 rd WEIGHT OF FUEL : grams (GRAIN OF SALT) CRASH TEST: 50 MPH REAR IMPACT ACID LEAK TEST HANG CAR VERTICALLY FOR 12 HR.S

23 TESLA MOTOR 375 volt AC induction air-cooled electric motor with variable frequency drive Max Net Power: 248 HP ( rpm (40-65 MPH) Max rpm 14,000 Efficiency 92% average, 85% at peak power Torque 276 ft/lb ( rpm (0-40 MPH)

24 TESLA TRANSMISSION Single speed fixed gear with electrically-actuated parking lock mechanism and mechanical lubrication pump Overall Final Drive 8.28:1 Reverse direction of motor, limited to 15 mph

32 Tesla Battery Fabrication and Disposal Lithium is the lightest naturally occurring element Largest Producers are located in Chile (65% of world s total), Argentina, Australia and China with a large deposit being developed in Bolivia Largest manufacturer of Lithium products is China Tesla battery is manufactured in Japan. The manufacturer complies with the Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment After use in the car, batteries can be used to level off grid power The battery modules will be recycled by Toxco in British Columbia The results of the current recycling process are: 60% of the materials are recycled 10% of the materials are reused 25% of the materials are disposed of

The Sustainable Transportation Initiative

The Sustainable Transportation Initiative Stanton Ireland, NBEAA Public Relations Director Chris Jones, NBEAA President www.nbeaa.org February 7, 2008 What Do We Need to Do? Transition to a sustainable