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    The Science of Electric Vehicles

    Alan Soule and Chris J onesNorth Bay Electric Auto Association

    www.nbeaa.org

    Presentation to Science Buzz CafFrench Garden Restaurant, Sebastopol

    J uly 22, 2010 6:30 PM

    This presentation is posted atwww.nbeaa.org/presentations/ev_science.pdf.

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    Alan Soule

    NBEAA PR Director

    Tesla Roadster owner

    Chris J ones

    NBEAA President

    Mustang EV Converter

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    Agenda

    Reasons to Drive an EV

    EV Components

    Buying an EV

    Driving an EV

    The Tesla Roadster

    EV Show and Tell

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    Energy Independence

    60% of 2006 US oil consumption was imported per the US Government EnergyInformation Administration Basic Petroleum Statistics,www.eia.doe.gov/neic/quickfacts/quickoil.html.

    Greenhouse Gas Reduction

    Transportation accounted for 42% of greenhouse gas emissions in Sonoma County in2000, according to the Climate Protection Campaigns J anuary 2005 reportGreenhouse Gas Emission Inventory for all sectors of Sonoma County, California,www.climateprotectioncampaign.org/news/documents/AP_INVEN.PDF.

    Air and Water Pollution Reduction

    Asthma cost $12.7B in 1998 and can be caused by vehicle exhaust, per the Center forDisease Control Asthma Speakers Kit, www.cdc.gov/asthma/speakit/default.htm.

    See www.nbeaa.org/bev_faq.htmfor more frequently asked EV questions.

    Reasons to Drive an EV

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    Energy Independence

    Efficiency: Petrol ICE

    EVs charged by

    ICE grid

    EVs offset by PVsmade by ICE grid

    EVs offset by PVsmade 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.

    Non-RenewableEnergyConsumed:

    100%

    71%

    24%

    0%

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    Greenhouse Gas Reduction

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    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% lessgas: $3 per gallon / 20 MPG = $.15 per mileelectric: $.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.

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    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 significantdifference in maintenance cost, and gas prices do not increase.

    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 Peets lattes

    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 Peets lattes

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    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, isscrapped in 10 years, the batteries deliver enough power and capacity for the life of thecar, there is no significant difference in maintenance cost, andgas prices do notincrease.

    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

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    EV Components

    Motor Batteries and Electronics

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    2-Pole Series Wound DC Motor Demonstration

    BrushCommutator

    Field Windings Armature Windings

    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.

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    Electric Motor Types

    No

    Yes

    No

    Yes

    Yes

    Yes

    brushes

    Opposing magnetic field inducedvia eddy currents caused by slipbetween stator and rotor in copperor aluminum squirrel cageframe

    Armature windings, PWMdvia rotor position sensor

    AC Induction

    Field windings, DC energizedthrough brushes and slip rings

    Armature windings, PWMdvia rotor position sensor

    AC Synchronous

    Field permanent magnetArmature windings, PWMdvia rotor position sensor

    DC BrushlessPermanent Magnet

    Armature windings, commutatedthrough brushes

    Field permanent magnetDC BrushedPermanent Magnet

    Armature windings, commutatedthrough brushes, separatelyexcited from field

    Field windingsDC Shunt

    Armature windings, commutatedthrough brushes and split rings, inseries with field

    Field windingsDC Series

    Rotor (rotating part)Stator (stationary part)type

    The fieldproduces a magnetic field to be acted upon by armature; it can be an electromagnet orpermanent magnet. The armaturecarries current normal to field to generate torque.

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    Electric Motor Types

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    Nail / Tube / Salt Water Battery Demonstration

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    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.

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    Battery Types

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    Batteries in Development

    Stanford University Silicon Nanowireelectrodes have 3X capacityimprovement expected for Lithiumbatteries

    Not technically a battery, but MITNanotube ultracapacitors have veryhigh power, 1M+ cycle energystorage approaching Lithium batterycapacity

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    Motor and Battery Charge Control via Pulse Width Modulation

    100%duty cycle

    75%

    50%

    25%

    0%

    on

    off

    on

    off

    on

    off

    on

    off

    on

    off

    time

    Reducing the duty cycle reduces the power delivered to the load.

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    Switch Mode Power Supply Buck Regulator:a common building block for motor and charge control

    Frompower

    source:batteries,grid or

    motor inregenmode

    To load: motor orbatteries

    Power switchingtransistors: MOSFETs

    or IGBTs

    FromPWMcontrolcircuit

    Freewheeldiodes

    Filtercapacitors

    When power is applied to input, capacitors are charged up. When transistors are switched on, current flowsfrom 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 motors magnetic fieldcollapses to keep from increasing the voltage across the transistor to the point of failure.

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    Buying an EV

    in the U.S.

    Refer to Plug In America Plug-in vehicle tracker

    Currently available EVs in California:Tesla Roadster ($109,000)

    EVs Scheduled for production:Audi e-tron 2011 ?BMW ActiveE 2011 ?CODA 2010 $45,000Daimler Smart EV 2012 ?Ford Focus 2011 ?

    Hyundai i10 Electric 2012 ?Mitsubishi iMiEV 2010 $47,000Nissan Leaf 2011 $22,000Peugeot iOn 2011 ?Rolls Royce 2010 ~$500,000Tesla Model S 2012 $50,000

    Toyota Rav4 (Tesla drivetrain) 2012 ?

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    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 EVs 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 becauseof limited public chargers

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    ELECTRICAL CAPACITY: 52.8 KWHR

    CELL CAPACITY: 7.73 WHR (2.2 AMPHR)

    QUANTITY OF CELLS: 6,831CELLS PER BRICK: 69

    BRICKS PER MODULE: 9

    MODULES PER BATTERY: 11

    BATTERY WEIGHT: 970 LB.S (CHARGED OR NOT)

    ELECTRON CAPACITY: 34.1328 X 10 to the 23rd

    WEIGHT OF FUEL: 0.003089 grams (GRAIN OF SALT)

    CRASH TEST: 50 MPH REAR IMPACT

    ACID LEAK TEST HANG CAR VERTICALLY FOR 12 HR.S

    Tesla Roadster

    TESLA BATTERY

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    TESLA MOTOR

    375 volt AC induction air-cooled electric motor with variable frequency drive

    Max Net Power: 248 HP (185 kW) @ 5000-8000 rpm (40-65 MPH)

    Max rpm 14,000 Efficiency 92% average, 85% at peak power

    Torque 276 ft/lb (375 Nm) @ 0-4500 rpm (0-40 MPH)

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    TESLA TRANSMISSION

    Single speed fixed gear with electrically-actuated parking lock mechanismand mechanical lubrication pump

    Overall Final Drive 8.28:1

    Reverse direction of motor, limited to 15 mph

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    Tesla Battery Fabrication and Disposal

    Lithium is the lightest naturally occurring element

    Largest Producers are located in Chile (65% of worlds 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 J apan. The manufacturer complies withthe Directive on the Restriction of the Use of Certain HazardousSubstances 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 recycled10% of the materials are reused25% of the materials are disposed of

    http://www.teslamotors.com/blog/mythbusters-part-3-recycling-our-non-toxic-battery-packs