Guidelines for Battery Electric Vehicles in the Underground Energy Storage Systems Rich Zajkowski Energy Storage Safety & Compliance Eng. GE Transportation
Agenda Terminology Let s Design a Battery System Safety Considerations Performance Standards Transportation Regulations Long Term Storage of Batteries Battery End of Life
Terminology: Electropedia.org (IEC) Cell: basic functional unit, consisting of an assembly of electrodes, electrolyte, container, terminals and usually separators, that is a source of electric energy obtained by direct conversion of chemical energy Electrolyte liquid or solid substance containing mobile ions which render it ionically conductive Lithium Metal Cell cell containing a non-aqueous electrolyte and a negative electrode of lithium or containing lithium Lithium Ion Cell secondary cell with an organic solvent electrolyte and positive and negative electrodes which utilize an intercalation compound in which lithium is stored Note A lithium ion battery does not contain lithium metal. Battery one or more cells fitted with devices necessary for use, for example case, terminals, marking and protective device. Battery System Battery plus enclosure, battery management system, thermal management system and connections to battery electric vehicle and battery charger
Designing a BEV Energy Storage System Select cell type for underground vehicle traction system Type Cell Voltage Energy Density (Wh / L) Specific Energy (Wh / kg) Cycle Life Maintenance Lead Acid 2.1 60-75 40 100 s Regular charging Nickel Cadmium 1.2 100 40 100 s Periodic exercise Nickel Metal Hydride 1.2 390 100 100 s Periodic exercise Nickel Zinc 1.6 280 100 100 s High self-discharge Lithium Ion 3.2-3.7 300-610 100-200 1,000 s Management System Diesel n/a 9,900 12,700
Designing a BEV Energy Storage System High energy density Reduced weight Long cycle life Maintenance free Non hazardous materials Type Cell Voltage Energy Density (Wh / L) Specific Energy (Wh / kg) Cycle Life Maintenance Lead Acid 2.1 60-75 40 100 s Regular charging Nickel Cadmium 1.2 100 40 100 s Periodic exercise Nickel Metal Hydride 1.2 390 100 100 s Periodic exercise Nickel Zinc 1.6 280 100 100 s High self-discharge Lithium Ion 3.2-3.7 300-610 100-200 1,000 s Management System Diesel n/a 9,900 12,700
Selecting a Lithium Ion Chemistry Selecting a Li-ion cell chemistry Considerations Power rating (W) Energy rating (Whr) Safety characteristics Minimum recharge time Operating environment Cycle life Cost Lithium Iron Phosphate (LFP) Lithium Nickel Cobalt Aluminum Oxide (NCA)
Arranging Cells into a Battery Battery electric vehicles (BEV) need high voltage Series connect cells to achieve 400-800 VDC V series = V cell x Qty cells Chose 600V = 3.3 V cell x 181 cells Energy requirements Energy = V series x Cell Ah 600V x 20 Ah = 12 kwh Assume LHD w/ 2 yd 3 uses 150 kwh rated battery 150 kwh / 12 kwh per series = 13 sets of 181 cells + Cell 1 Cell 2 Cell 3... _ Cell 181
Arranging Cells into a Battery Parallel connect series of cells to achieve 150 kwh How many cells are in battery system? 181 cells x 13 sets 2,353 cells Maintenance tasks: Balance cell voltages Measure cell state of charge Identify failing cells Isolate failed cells Monitor cell temperatures and current + _ Cell 1 Cell 2 Cell 3 + Cell 1 Cell 2 Cell 3...... Cell 181 _ Cell 181
Battery Management System System that monitors individual or groupings of cells Ensures cells operate in their safe zone Balances charge levels of individual cells Measure, monitor & communicate: Cell voltages, currents & temperatures Energy consumed by the vehicle System state of charge (SOC) System depth of discharge (DOD) Overall battery health and capacity I up T V Cell
Safety Considerations Risk analysis Never attempt maintenance or repair on your own OEM should provide: Preventative maintenance program Battery system inspection checklist Any special repair or maintenance procedures Complete risk analysis with assistance of the equipment manufacturer Risks can vary with cell chemistry, battery system design and environmental conditions
Potential Failure Modes Non Energetic: Loss of capacity Activation of battery system protective device Swelling of cells Electrolyte leakage or evaporation Battery no longer capable or operating vehicle Energetic (thermal runaway): Venting of hazardous and flammable gases Carbon dioxide, hydrogen, carbon monoxide, nitrogen, methane Venting of flames Extreme temperatures at failed cell Rapid disassembly of cell
Safety & Hazard Considerations Batteries present inherent hazards: Electric shock Cell voltage can t be turned off Arc flash Battery enclosure design should prevent accidental exposure to arc flash Lithium ion battery hazards may arise from: Charging and discharging at low temperature (may cause lithium plating) Over-voltage / over-charging Under-voltage / over-discharging Over-loading / over-current Over-temperature External short circuit Internal short circuit External over heating Chemical reactions Crush, shock, penetration or rupture of a cell
Safety Considerations Lithium ion battery hazards may arise from: Charging and discharging at low temperature (may cause lithium plating) Over-voltage / over-charging Under-voltage / over-discharging Over-loading / over-current Over-temperature External short circuit Internal short circuit External over heating Chemical reactions Crush, shock, penetration or rupture of a cell Battery Management System (BMS) primary mechanism to prevent these conditions
Safety Considerations Lithium ion battery hazards may arise from: Charging and discharging at low temperature (may cause lithium plating) Over-voltage / over-charging Under-voltage / over-discharging Over-loading / over-current Over-temperature External short circuit Internal short circuit External over heating Chemical reactions Overcurrent protection / fusing Crush, shock, penetration or rupture of a cell
Safety Considerations Lithium ion battery hazards may arise from: Charging and discharging at low temperature (may cause lithium plating) Over-voltage / over-charging Under-voltage / over-discharging Over-loading / over-current Over-temperature External short circuit Internal short circuit External over heating Chemical reactions Crush, shock, penetration or rupture of a cell Appropriate battery storage, physical protection, proper usage and handling
Safety Standards SAFETY Safety standards not globally harmonized Primarly targeting electric road vehicles CSA E62660-2 / IEC 62660-2 Secondary lithium-ion cells for the propulsion of electric road vehicles Part 2: Reliability and abuse testing UL 2580 Batteries for Use In Electric Vehicles UN ECE 324 Regulation 100, Uniform provisions concerning the approval of vehicles with regard to specific requirements for the electric power train Standard Over-charge Over-discharge Short Circuit Temperature Test Imbalance Charging Thermal Management Failure Shock / Vibration / Crush Thermal Cycling / Exposure to Fire CSA E62660-2 IEC 62660-2 X X (no fire exposure) UL 2580 UN ECE 324 X X (no crush)
Performance Standards Performance standards not globally harmonized Primarly address lithium-ion cell performance CSA E62660-1 / IEC 62660-1 Secondary lithium-ion cells for the propulsion of electric road vehicles Part 1: Performance testing SAE J2288 Life Cycle Testing of Electric Vehicle Battery Modules Standard Power Density Energy Density Charge Retention Cycle Life Energy Efficiency CSA E62660-1 IEC 62660-1 SAE J2288 X X X X
Transportation Regulations Majority of regulations reference UN 38.6 United nations: ST/SG/AC.10/11 Rev 5 (UN 38.3, lithium metal and lithium ion batteries) US CFR Parts 100-177 (173.185: Lithium Cells and Batteries) Canada TDG - Transportation of dangerous goods IMDG - International Maritime Dangerous Goods Code ADG Australian Code for Transport of Dangerous Goods, Edition 7.4 IATA - International Air Transport Association Dangerous goods regualtions Standard Altitude Thermal Shock / Vibration Short Circuit Impact Overcharge Forced Discharge UN 38.6 US CFR Parts 100-177 Canada TDG IMDG ADG 7.4 IATA
Li-Ion Transport Pre-Cautions Lithium ion transport regulations often require: Cell & battery packaging that meets UN 38.3 test criteria Specific markings and visibility requirements Damaged, defective or recalled cells & batteries be transported in authorized containers using defined packing methods Dangerous goods / hazmat training for persons packaging cells and batteries Regulations are frequently amended Maintain awareness: subscriptions, websites, newsletters Always consult with OEM before packaging or transporting battery systems or components
Long Term Battery Storage Consult OEM for storage conditions Temperature 15-20 C common recommendation, higher temperatures reduce life State of charge (SOC) when battery placed into storage typically 40-50% storing above 50% SOC may cause un-recoverable capacity loss Battery life without any periodic recharge 2-4% self discharge per month achievable under ideal conditions Life with periodic recharge Procedure and equipment used to maintain battery Procedures for handling failed or damaged batteries
Battery End of Life OEM should provide decommissioning and disposal instructions Warning: depleted batteries can contain significant amounts of energy BEV battery systems may find second use applications Solar (PV) applications Utility energy storage applications Lithium ion batteries should be disposed of or recycled according to local laws and regulations. Never burn or incinerate lithium-ion batteries
Questions? Thank you! Rich Zajkowski richard.zajkowski@ge.com 740-417-5373