Stationary Battery Safety An Overview of the Process of Verifying the Safety of Battery Systems Laurie Florence Principal Engineer Batteries, Fuel Cells & Capacitors Laurie.b.florence@us.ul.com 1-847-664-3782
Leader in Advanced Battery Safety Science Research Design Advisory Thought Leadership Testing & Certification Battery Standards UL 810A: Electrochemical Capacitors UL 1973: Stationary Applications UL 2271: Light Electric Vehicles UL 2580: Electric Vehicles UL 9540: Energy Storage Systems 2
Agenda Applications for Stationary Batteries Importance of Safety Codes and Standards Affecting Stationary Batteries Safety Approach of UL 1973 Approaches to Validating Safety of Stationary Batteries Introduction to UL 9540 Timelines & Future Work 3
Applications for Stationary Batteries Support for renewables: mitigating intermittency of renewables Transmission and distribution support Grid support: load leveling, frequency response, peak shaving, etc. Smart Grid and micro grids:
Applications for Stationary Batteries Critical power backup: datacenters, hospitals, etc. Residential applications: Other Commercial applications
Importance of Safety US Department of Energy (DOE) Energy Storage Safety Strategic Plan (Dec 2014) Safety of any new technology can be broadly viewed as having three intimately-linked components: 1) a system must be engineered and validated to the highest level of safety possible 2) techniques and processes must be developed for responding to incidences if they do occur 3) the best practices and system requirements must then be reflected through standardized safety determinations in the form of codes, standards and regulations (CSRs) so that there is uniform written guidance for the community to follow when designing, building, testing and deploying the system.
Importance of Safety The safety approach depends upon a number of factors: Technology Traditional vs Emerging Location Urban vs rural Industrial/ Commercial vs Residential Application Power vs Energy Continuous vs Intermittent Size and Scale
The Importance of Safety Fires As an energy source, an electric energy storage system may represent a potential energy hazard, which could lead to Hazards: Energy Explosions 8
The Importance of Safety Electric Shock As a source of electricity, an electric energy storage system may represent a potential electrical hazard, which could lead to: Hazards: Electrical Arc Flash 9
The Importance of Safety Depending upon technology, etc., systems may be a potential source of exposure to harmful materials, which could result in: Concentrations of hazardous gases Hazardous liquid spills Hazards: Hazardous Materials Exposures to hazardous solids 10
The Importance of Safety There may be potential for physical hazards associated with the EESS such as: Burns Hazardous Moving Parts or Pinch Parts Hazards: Physical Slip or other physical hazard 11
Codes and Standards Affecting Safety of Stationary Batteries Codes NFPA 70, National Electrical Code (NEC) Art. 480 New Art. 706 (under dev.) NFPA 1, Fire Code Chp. 52 ICC IFC (International Fire Code) Sec. 608 ICC IBC (International Building Code) Sec. 509 Standards ANSI/UL 1973, Batteries for Use in Light Electric Rail (LER) Applications and Stationary Applications UL 991/1998 or UL 60730-1 UL 60950-1 UL 746C IEEE 1375, Guide for the Protection of Stationary Battery Systems IEC 62485-2, Safety requirements for secondary batteries and battery installations Part 2: Stationary batteries UL 9540, Energy Storage Systems and Equipment ANSI/UL 1973 ANSI UL 1741 IEEE 1547 and 1547.1
Codes and Standards Affecting Stationary Batteries UL 1973 Batteries for Use in Light Electric Rail (LER) Applications and Stationary Applications Scope Safety standard Cells, Modules, Batteries and Battery Systems for: Stationary applications Light electric rail (LER) applications Non-chemistry specific but includes specific criteria for: Lithium ion Ni-cad and NimH Sodium sulfur (NAS) and Sodium nickel chloride (ZEBRA) Lead acid Flow batteries Electrochemical capacitors
Safety Approach of UL 1973 Safety Analysis Analysis of battery with single fault conditions FMEA, FTA, etc. Construction Materials Enclosure Electrical Spacings Insulation Wiring and Components Safety controls/ protection Cells Testing Electrical Mechanical Environmental Markings, Instructions, Production tests
Safety Approach of UL 1973 Safety Analysis Applies to parts, components and circuits affecting safety Risk assessment, FMEA, FTA, etc. IEC 60812, IEC 61025, etc. can be used as a guide ID critical safety controls Single fault conditions Safety critical electronics and software Must meet functional safety requirements UL 991/UL 1998, UL 60730-1, IEC 61508 Determine severity level, performance level or class
Safety Approach of UL 1973 Materials Construction Plastics, non-metallic: flammability, temperature, insulation, strength, resistance to chemicals Metal Corrosion resistance, strength Enclosure Strength, material properties, openings Electrical Spacings (creepage and clearances) Insulation levels & grounding Wiring Components Safety controls Piping & pressure vessels Spill containment UL Subject 2436 Cells Lithium ion Clause 5.11 or Appendix E Ni-Cad, Ni-mH Clause 5.11 Sodium beta Appendix B Lead acid Clause 5.11 & UL 1989 Flow batteries Appendix C Electrochemical capacitors UL 810A
Safety Approach of UL 1973 Battery Testing - General Combustible concentration determination Monitoring method Spark ignition method - Toxic gas monitoring Applicable to indoor units and walk in units Shock hazard determination Dielectric voltage withstand Observation period 1 hour After test cycling If operational General test ambient 25 ± 5 C MOSOC Typically 100% SOC Battery Samples Representative of production One per test Representative subassemblies Can use samples for multiple tests If doesn t affect results Can do minor repairs 17
Safety Approach of UL 1973 Battery Electrical Tests Overcharge Short Circuit Overdischarge Protection Imbalanced Charging Temperature & Operating Limits Check Dielectric Voltage Withstand Continuity Failure of Cooling/Thermal Stability System Working Voltage Measurements Battery Mechanical Tests Static Force Impact Drop Impact Wall Mount Fixture/Handle Test Mold Stress Battery Environmental Tests Resistance to Moisture Salt Fog External Fire Exposure Internal Fire Exposure
Safety Approach of UL 1973 (Pack/Module) Overcharge Short Circuit Overdischarge Protection Battery Pack/Module Tests Temperature & Operating Limits Check Imbalanced Charging Dielectric Voltage Withstand Failure of Cooling/Thermal Stability System Static Force Impact Drop Impact Resistance to Moisture Salt Fog External Fire Exposure Internal Fire Exposure Noncompliant Results Criteria A E, F, C, V, S, L, R, P E, F, C, V, S, L, R, P E, F, C, V, S, L, R, P E, F, S, L, R E, F, C, V, S, L, R, P S E, F, C, V, S, L, R, P E, F, C, V, S, L, R, P E, F, C, V, S, L, R, P E, F, C, S, L, R, P E, F, C, V, S, L, R, P E, F, C, V, S, L, R, P Results Key: E Explosion, F Fire, C Combustible vapor, V Toxic gas concentration, S Dielectric breakdown, L External leakage, R Rupture, P Loss of protection controls A Additional criteria for some tests outlined in specific sections. E E, F
Safety Approach of UL 1973 - Cell Overcharge UL 1973 Cell Tests L, S High Rate Charge L, N, Short Circuit Forced Discharge Vibration Shock Crush Impact Drop Temperature Cycling Heating Altitude Simulation Projectile L, N, S, F L, N L, N, S, F L, N, S, F L, N L, N L L, N, S L, N, S L L, N Chemistry Chemistry Key: L Lithium ion, N Nickel Cadmium or Nickel Metal Hydride, S Sodium Beta, F- Flow Battery Stack NOTE: In 2 nd ed., Lithium ion will have a choice between 5.11 test program or App. E test program
Approaches to Validating Safety of Stationary Batteries Depends upon AHJ Location of installation/ Application Technology/ Chemistry Labelled equipment? Codes? Utility, Commercial, Residential New vs old chemistry Region, State, City Unique designs
Approaches to Validating Safety of Stationary Batteries Verification of stationary battery safety: Self Verification Use of 3 rd Party to Verify Safety Certification 3 rd party testing and evaluation (without certification) Field Evaluation by 3 rd party What are the Codes & Regulations for installation? Does code require Listing? What does AHJ want? 22
Approaches to Validating Safety of Stationary Batteries Why Certification? Ease of acceptance & installation Due diligence Local requirement AHJ UL 1973 referenced in 4.3.8 of UL 60950-1 for stationary batteries 2017 NEC will require Listed equipment for EESS What Does 3 rd Party Certification Entail? Listing Certification Process Compliance to UL 1973 Battery System Listed; and Component Batteries, Modules and Cells Recognized under UL 1973 certification programs see www.ul.com/database Ongoing production inspection UL Listing or Recognition Mark Field Evaluation Conducted on installed product with cooperation of AHJ Non-destructive evaluation No production inspections Field label marking 23
Approaches to Validating Safety of Stationary Batteries Modular Approach to Listing/Recognition Investigation Preliminary review of construction Certification FMEA BoM ID and review of critical components Technical documentation Test program parameters Address outstanding items of preliminary investigation Testing Finalization of certification documents Set up ongoing production documents and UL labels
Introduction to UL 9540 UL 9540, Energy Storage Systems and Equipment: Scope Safety Standard Includes electrical energy storage (EES) systems that are: Standalone to provide energy for local loads; In parallel with an electric power system, electric utility grid; or Able to perform multiple operational modes For use in utility-interactive applications in compliance with IEEE 1547 and IEEE 1547.1 or other applications intended to provide grid support functionality May include balance of plant and other ancillary equipment of the system Electrical Energy Storage DC/AC PCS Auxiliary Equipment Electrical Energy Storage System System boundary Electrical Connection Point (ECP) Circuit Breaker Power Grid
Overview of UL 9540 Requirements Thermal Under development Mechanical Under development Types of Energy Storage Systems Chemical Electrochemical UL 1973 26
Timelines & Future Work UL 1973, 1 st edition Feb 2013 ANSI/UL 1973, 2 nd Edition 3 rd quarter 2015 ANSI/UL 1973, US & Canada Bi-national Standard 4 th quarter 2015
Timelines & Future Work UL 9540 Bulletin2nd quarter 2015 ANSI UL 9540 1 st edition, 4 th quarter 2015 UL Subject 9540, June 2014
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