Electric Vehicle Safety: Design & Research
Alvaro Masias Energy Storage Research, Ford Motor Company ARPA-E Crash-Safe Energy Storage Systems for Electric Vehicles Workshop Denver, CO – November 12, 2012
Page 1 Table of Contents
Design
Research
Page 2 Table of Contents
Design
Research
Page 3 Power of Choice ELECTRIFIED VEHICLES TRIPLING PRODUCTION CAPACITY
IN NORTH AMERICA BY 2013
Page 4 Ford Focus Electric
110 MPGe Advanced Li-Ion Battery
5 PASSENGER 25-30% smaller LIQUID-COOLED 23kWh FASTER CHARGING 50% lighter
LITHIUM-ION BATTERY PACK
MORE EFFICIENT BATTERY TEMPERATURES Page 5 Reliability
Researching and developing modern electrified vehicles for decades
1996 1998 2004 2009 2010
Cell Testing and Research Ford Escape Hybrid
Ford Ranger Electric Ford Fusion Hybrid
Page 6 Focus Electric Battery Location
BEV Upper Battery Pack is mounted in the trunk behind the second row seats. Lower portion of pack extends through trunk floor to the outside of the vehicle
BEV Lower Battery Pack is mounted under the vehicle below the second row seats
Page 7 Crash Requirements – FMVSS 305
30mph Rigid Barrier
30mph 50mph 70% Overlap 30 o Left & 33.5mph Left & Right V-to-V Left & Right Right o Angular 27 Crabbed Cart
Frontal Crash Events Side Crash Events Rear Crash Events
Page 8 Public Domain & Additional Ford Crash Testing
35mph NCAP 20mph Oblique th th% NCAP Left & Right Pole (5 /50 ) Rigid Barrier
High Speed V-to-V Left & Right 40mph 40% Rear High Speed IIHS Offset V-to-V Left & Right Side
38.5mph NCAP Left & Right Side MDB 31mph Left IIHS Cart
Page 9 FMEA Analysis
Noise Factors & Potential Prevent Stress Failure Modes Effects Actions Normal Conditions Over Temperature No Effect Vehicle Level Design Actions Over Charge Protection Noise Factors Activated Over Discharge Pack Level Damage/ Design Actions Off-Normal Conditions External Short Retention
Internal Cell Short Leakage Cell Level Failure Modes Design Actions Venting
Fire/Flame
Page 10 Vehicle, Pack & Cell Level Actions
Pack Level Actions
• Battery Pack Structure • Vent Management Sys • Pack Cooling Sys • Battery Controls Sys Vehicle Level Actions • Power Limits (Temp, Age, others) Cell Level Actions • Over Temp • Vehicle Structure • Over Charge/Discharge • Cell Chemistry • ENS Control • Vehicle Cooling Sys • Cell Balancing • Cell Design • Battery Sensors (V, I, T) • Vehicle Control Sys • Fusing • Cell Manufacturing (occurrence reduction) • Charging Control Sys
Page 11 Typical Testing & Verification
Examples of typical tests that may be conducted on battery cells, battery pack assemblies, and/or entire vehicles.
Vibration, Shock, Battery Enclosure Mechanical Integrity Electrical Short Circuit, Over Charge & Electrical Discharge Protection High/Low Temperature Exposure, Environmental Thermal Shock, Humidity and Moisture Exposure, Corrosion, Immersion
Page 12 Focus Electric – Vehicle Level Structural Components
Unique Designed (Material &/or gauge revised)
Structural additions for battery pack crash protection
Page 13 Focus Electric – Battery Pack Level Structural Components
Battery Pack Casing
Casing modifications for enhanced crash protection
Page 14 Focus Electric – Rear Body Structure
Page 15 Table of Contents
Design
Research
Page 16 Battery Safety Research
Battery Safety Hazards Project Summary
System: NHTSA Research Funding System • COTR Gorney (2yr) • Vehicle Lithium Ion Battery Hazard Test Method Development Mechanical Thermal Mechanical: Ford-MIT Alliance Funding • Prof. Wierzbicki (2yr) • Lithium ion battery mechanical crush modeling and prediction Thermal: Ford URP Funding • Prof. Sunderland/Stoliarov (3yr) • Lithium ion battery thermal hazard Electrical assessment & comparison Electrical: Ford-UM Alliance Funding • Prof. Mi (2yr) • Battery management system (BMS) controls & requirements Fundamental: TBA (Proposal Stage) Fundamental TBA • Prof. John Doe (1+1.5yr) • First Principles of Cathode / TBA Electrolyte Interactions
Page 17 NHTSA Solicitation: Overview
Scope HEV/PHEV/BEV Li-Ion Battery Develop Safety Test Methods & Purpose Performance Safety Metrics • Active – Single Failure Tasks • Passive – Single Failure + Loss of Control System • Mechanical: Crush, Penetration, Timing Vibration, etc. Solicitation 1/26/11 Fault • Electrical: Overcharge, Short Circuit, Proposal 4/21/11 Origin Overdischarge, etc. • Thermal: Fire Resistance, Thermal Award 9/30/11 Control, etc. Finish 9/29/13
Page 18 NHTSA Solicitation: Awards
Primary
Sub- contractor
Page 19 Ford Approach: Overview
• Goal: Repeatable vehicle level Li-ion based RESS safety performance test procedures
• Approach: Define vehicle level performance tests which draw upon the cell, module and pack level information.
Page 20 Ford Approach: Process
Test Method Fault Tree Analysis Survey Development Testing
Fault Tree Failure Mode Analysis & Analysis F Effects Analysis Refinement a • Design u • Design Independent l dependent t • Deductive • Inductive (Top Down) (Bottom Up) Iteration
Chose FTA for NHTAS RESS Project • Broadly applicable (Design Independent) • Event Path Dependence (Multiple Fault Scenarios) Page 21 Ford Approach: Fault Tree Analysis
Failure Categories
Thermal Electrical Chemical Mechanical
Page 22 Table of Contents
Design
Research
Page 23 Great Products, Strong Business, Better World
Page 24