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Model S – A Game Changer of Electric Vehicle

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Presentation on theme: "Model S – A Game Changer of Electric Vehicle"— Presentation transcript:

1 Model S – A Game Changer of Electric Vehicle
Yih-Charng Deng (鄧益常) Technical Fellow, Crash Safety, Tesla Motors Weilin Chang (張維麟) Engineering Manager, Power & Vehicle Electronics, Tesla Motors

2 Transportation Issues Facing the Human Race
Global automobile population > 1 billion in 2010 (Ward’s Auto report) Will double by 2030 Not sustainable (petroleum & capacity for production, greenhouse gases emission) Sperling & Gordon, 2009, Two Billion Cars: Driving Toward Sustainability Vehicle transformation (hybrid, electric, etc.) Fuel transformation (biofuel, hydrogen, etc.) Mobility transformation (rapid mass transit, telecommunication, etc.)

3 History of EV In 1900: 40% steam, 38% electricity, 22% gasoline
In 1920s, IC engine vehicles started to dominate Air pollution problems in major US cities 1990 Clean Air Resources Board (CARB) of CA & Zero-Emission Vehicle (ZEV) mandate EV1 from GM ZEV abolished in 2003, EV1 program terminated by GM

4 Fuel Economy Drive 1975 – Corporate Average Fuel Economy (CAFÉ)
2007 – Energy Independence and Security Act (EISA), 35 mpg by 2020 2009 New Fuel Economy Proposal – 35.5 mpg by 2016 2011 US Government Agreement w/ 13 Car Manufacturers – 54.5 mpg by MY2025 Hybrid vehicles and new wave of EV

5 EV Advantages/Disadvantage
Higher efficiency (80%), 3 times that of IC engine Energy chain (source to wheels) – EV is 10-30% more efficient (expect to increase) Can use clean energy source at power plants (solar, wind, hydro) Current EV’s < 100 miles range 2012 Model S from Tesla Motors Over 300 miles range 0 to 60 mph in 4.4 sec.

6 Electric Vehicle Powertrain
Type of EV Electric Propulsion System Energy Storage System (Primary) Energy Storage System (Secondary) Electrical Charge Vehicle Model Battery EV All Electric Motor Battery Pack External Power Source & Regenerative Brake Tesla Roadster, Model S, Nissan Leaf Fuel Cell EV Fuel Cell Extended Range EV Hybrid (ICE as generator) Gasoline Tank for Generator External Power Source, Regenerative Brake & Generator (ICE) GM Volt Plug in EV Motor & ICE Gasoline Tank Fisker Karma, Toyota Plugin Prius Hybrid EV Regenerative Brake Toyota Prius

7 EV Energy Efficiency Electric Vehicle Efficiency
Internal Combustion Vehicle Efficiency Hybrids and Plug-In Hybrid Vehicle Efficiency

8 All Electric Powertrain
Energy Storage System (Battery Pack) Propulsion System: Motor Gearbox Inverter Charger

9 Battery Design Cell: Cell selection Energy & power density
Cycle and calendar life Module: Safety protection technology (open, short & propagation) Voltage balancing Package density Isolation and thermal management Battery Pack: Safety protection circuit Lightweight & durability Design for quick swap

10 Battery Cell Form Factor
Cylindrical Cell: Good cycling ability, mechanical stability, economical for manufacturing Heavy and relative low package density Prismatic Cell: Optimal use of space by using layered approach, improving space utilization, and allowing flexible design to achieve higher package density, the metallic housing providing mechanical stability More expensive, less efficient in thermal management, shorter cycle life Pouch Cell: Simple, flexible and lightweight solution to battery design, highest package efficiency, cost-effective for manufacturing Swelling factor, shortest cycle life and less durable

11 Cell Chemistry

12 Why Lithium-ion Advantages
Today’s lithium-ion cells have the highest density w/ a good balance of power density Relatively low self-discharge, less than half that of NiCd and NiMH Low maintenance, no periodic discharge needed No memory effect Challenges Requires protection circuit to limit voltage and current Subjects to aging, even if not in use Transportation regulations when shipping in larger quantities Higher cost

13 Lithium-Based Battery Comparison
Specifications Li-cobalt Li-manganese Li-phosphate NMC LiCoO2 (LCO) LiMn2O4 (LMO) LiFePO4 (LFP) LiNiMnCoO2 Voltage 3.60V 3.80V 3.30V 3.60/3.70V Charge limit 4.20V Cycle life2 500–1,000 1,000–2,000 Operating temperature Average Good Specific energy 150–190Wh/kg 100–135Wh/kg 90–120Wh/kg Wh/kg Specific power 1C 10C, 40C pulse 35C continuous 10C Safety Average. Requires protection circuit and cell balancing of multi cell pack. Requirements for small formats with 1 or 2 cells can be relaxed Very safe, needs cell balancing and V protection. Safer than Li-cobalt. Needs cell balancing and protection. Thermal. runaway3 150°C 250°C 270°C 210°C (302°F) (482°F) (518°F) (410°F) Cost Raw material high Moli Energy, NEC Hitachi, Samsung High In use since 1994 1996 1999 2003 Researchers, manufacturers Sony, Sanyo, GS Yuasa, LG Chem Samsung Hitachi, Toshiba Hitachi, Samsung, Sanyo, GS Yuasa, LG Chem, Toshiba A123, Valence, GS Yuasa, BYD, JCI/Saft, Lishen Sony, Sanyo, LG Chem, GS Yuasa, Hitachi Samsung Moli Energy, NEC Notes Very high specific energy, limited power; cell phones, laptops High power, good to high specific energy; power tools, medical, EVs High power, average Very high specific energy, high power; tools, medical, EVs specific energy, elevated self-discharge

14 Model S Battery Equipped with over 7000 lithium-ion cells to provide up to 85kWh total energy capacity Active liquid cooling/heating thermal management system Total weight about 600kg and located underneath the floor, resulting in low center of gravity for high resistance to rollover and excellent vehicle handling Model S achieves 320 miles range based on EPA-2 cycle procedure Touchsafe quick disconnect for battery replacement or maintenance Multi-layers of safety protection features from cell, module to pack design Capable of supercharge (high current charging) 8 years, unlimited miles warranty

15 Battery Pack Options of Model S

16 Factors Influence Range

17 Range vs. Speed Model S Cd = 0.24 EPA 2-cycle: 320 miles
New record for EV

18 Propulsion System Rear wheel drive propulsion system to provide better acceleration, road handling and no torque steering Fully integrated system (motor, gearbox and inverter) to provide world record power density and reduce transmission power lose between sub-systems to increase power efficiency Liquid cooling system for thermal management Significantly less moving parts compared with ICE resulting in simplicity, reliability, low material and operation cost IP6K9K ingress protection and IP8X under wading line depth Communicate with vehicle through CAN and generate desired torque based on paddle position and inputs from other modules

19 Propulsion System – Motor
Three-Phase, four- poles AC induction motor Why AC motor (vs. DC brushless motor): Cost, no rare-earth metal for permanent magnets Efficiency, adjustable magnet field strength Performance Max torque: 600 Nm (443 lb-ft) during rpm Max power: 416 hp (310 kW) during 5K-8.6K rpm Top speed: 1600 rpm (130 mph) Efficiency: Over 90%

20 Torque Speed and Power Curve

21 Propulsion System – Gearbox
Single speed, oil-cooled, open-differential transaxle gearbox Fixed gear reduction ratio 9.73 to optimize top speed and range No transmission and clutch to reduce system complexity and cost Electrically actuated park brake Design challenges High motor rpm Thermal management High power and torque Durability

22 Propulsion System - Inverter
Paralleling discrete IGBT’s forming half bridge power stage to convert DC to 3 phase AC Capable of converting AC back to DC to charge battery during regenerative brake Rated at 450A rms continuous current Digital controller generating PWM to control switch Coprocessor to ensure no misinterpretation of accelerator paddle position while generating torque Continuously monitoring inputs from vehicle and other modules to determine current needed for desired torque Several layers of safety features, hardware & software

23 Motor Control Algorithm
Vector control (also called FOC) is a variable frequency drive control algorithm to control speed and torque of motor. Vector control outperforms other motor control algorithm (such as Scalar and DTC) because the non-constant vehicle speed and quick response time requirements in real driving situation. Both direct and Indirect FOC to calculate rotor flux position Produce desirable torque through flux control and torque-producing current Commercial DSP available for vector motor control (Clarke and Park transformation)

24 Vector Control Block Diagram

25 Onboard Charger Each box is capable of 10KW charging, up to 31 miles per hour of charge for Model S Option to add 2nd charger in parallel to increase to 20kW charging capacity (62 miles/hour) Single phase, acceptable voltage range from V at frequency 45-65Hz Trickle charge if power source voltage is greater than battery voltage Peak charger efficiency of 92% Maximum charge current at normal condition 110V: 20A from power source 240V: 40A from single phase power source Program charging schedule through vehicle touch screen and check charging status remotely

26 Charging Infrastructure
Universal Mobile Connector: 110V, 240V and J1772 public charging station adaptors are standard to ensure compatibility to different electrical outlets through different regions or countries. GFCI protection Communicate charging status and fault condition through indicator light NEMA 4 environment sealed enclosure for outdoor usage High Power Wall Connector: Wall-mounted charger to provide up to 20kW charging capacity Enclosure design meets NEMA 3R for environmental protection Draw up to 80A from electrical outlet during charge Supercharger: Dedicated industrial graded high speed charge station Charge half the battery (85kWh) in 30 minutes

27 Powertrain Components from Taiwan
Existing Projects: Roadster & OEM Programs: PEM, Charger, stator, rotor, motor shaft … Model S Components: Motor steel laminations, gears … Taiwan Industry Strengths: Power and vehicle electronics Motor & gears Machining, sheet metal & die casting parts

28 Other Salient Features – Body
Lightweight aluminum materials for maximum mass savings Double octagon rails for high energy absorption in crash High strength steel used in the B-pillars and bumpers Superb side impact and rollover protection Structural reinforcement for rear impact protection

29 Chassis Double wishbone, virtual steer axis front suspension and independent multi-link rear suspension Optional air suspension Edmunds INSIDE LINE

30 Interior 17” Capacitive Touchscreen Optional all-glass panoramic roof

31 Safety 8 airbags Retractor pretensioners Load limiters
5 point belt systems for the optional 3rd row child seats Sensors to trigger high voltage battery cut-off Extensive CAE in the design and development phases

32 Compared with Other Cars
Motor Trend 8/27/12 Automobile Magazine’s 2013 Automobile of the Year Testing 10/9/12: Model S out-dragged BMW M5 (560 hp, 501 lb-ft torque) in mph race

33 Tesla Supercharger Network

34 Tesla Supercharger Network
6 locations unveiled on 9/25/12 Solar carport systems, free charge for Model S owners indefinitely Slight net positive power transfer back to the electricity grid More supercharger stations in the US, Europe and Asia in 2013

35 Concluding Remarks Team dedication Relentless pursuit of excellence
Open working environment 2012 production all reserved Extremely positive feedback from customers and car critics (WSJ, USA Today, Motor Trend, 2013 Car of the Year – Yahoo Autos, Automobile Magazine) A sea change of automotive landscape


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