Flammability Characterization of Li-ion Batteries in Bulk Storage

Transcription

1 Flammability Characterization of Li-ion Batteries in Bulk Storage Benjamin Ditch Global Research Update: High Challenge Storage Protection 22 May 2014, London, England

2 Goal Develop sprinkler protection recommendations for bulk storage of Li-ion batteries

3 Markets Automotive industry Consumer electronics Power tools

4 How to Evaluate Li-ion Batteries Large-scale evaluation not feasible Provides direct evaluation of protection Requires multiple pallets loads Commodity expensive and difficult to acquire Reduced commodity approach Limit commodity to one pallet load per test Freeburn (no water)

5 Combustible Product (Li-ion batteries or standard commodity) Ring burner Non-combustible Rack storage configuration 3-tier storage Single-row rack Commodity lining ignition flue Bottom tier non-combustible Simulate fire from 1 st tier Propane ring burner, ~50 kw 5 MW Fire Products Collector Side Elevation View Ignition flue

6 Reduced-Commodity Approach 1. Estimate time-of-involvement of Li-ion Batteries Time in fire development where the batteries are observed to contribute to the fire severity 2. Characterize fire development up to theoretical sprinkler operation 3. Compare predicted sprinkler operation time versus time of battery involvement Ditch, B. and de Vries, J., Flammability Characterization of Lithium-ion Batteries in Bulk Storage, FM Global Research Technical Report, March 2013,

7 Heat Release Rate FM Global Fire Growth Comparison High Hazard Sprinkler operation Low Hazard Time

8 Commodities Baseline and Li-ion Batteries

9 Baseline Commodity Class 2 Cartoned Unexpanded Plastic

10 Array Configuration [50 kw] Class 2 Cartoned Unexpanded Plastic

11 Cylindrical Cells 19,200 cells total Cobalt oxide

12 Power Tool Battery Packs 200 power packs total 2,000 cells total Nickel mang. cobalt oxide

13 Polymer Cells 15,552 cells total Cobalt oxide

14 Results and Analysis

15 Fire Development 30 s 90 s 360 s 480 s Characterization period 75 ± 5 s for each commodity

16 Convective Heat Release Rate (kw) FM Global Heat Release Rate 5000 CUP - Test 7 Class 2 - Test Time (s)

17 Convective Heat Release Rate (kw) FM Global Heat Release Rate CUP - Test 7 Class 2 - Test 10 Li-ion Cylindrical Cells Li-ion Power Tool Packs Li-ion Polymer Cells Similar initial fire growth rate Packaging and mass impacts fire growth Involvement observed for polymer and cylindrical cells Time (s)

18 Sprinkler Link Response Measure convective flow from fire Calculate fire plume temp and velocity Rack storage height Clearance above commodity Calculate response of sprinkler link Link rating and response

19 QR Sprinkler Response Fire sprinkler operation Quick-response sprinkler, 74 o C link rating, 3 m clearance (165 o F link rating, 10 ft clearance )

20 Rack Storage Configuration Configuration Units Value Sprinkler RTI m 1/2 s 1/2 Link Rating Ceiling Clearance [ft 1/2 s 1/2 ] o C [ o F] m [ft] 27.6 and 170 [50 and 300] 74 [165] 3.0 and 4.6 [10 and 15]

21 QR Sprinkler, 3 m (10 ft) Clearance Commodity Link Operation Time (s) Q be (kw) Fire Growth Rate (kw/s) Class CUP Li-ion Cylindrical Cells Li-ion Power Tool Packs Li-ion Polymer Cells Fire size at sprinkler operation, Q be (kw)

22 Compiled Sprinkler Response (s) Commodity 3 m (10 ft) Ceiling 4.6 m (15 ft) Ceiling QR SR QR SR Class CUP Li-ion Cylindrical Cells Li-ion Power Tool Packs Li-ion Polymer Cells Excludes all sprinkler operation times greater than 75 ± 5 s

23 Convective Heat Release Rate (kw) FM Global Battery Involvement CUP - Test 7 Class 2 - Test 10 Li-ion Cylindrical Cells Li-ion Power Tool Packs Li-ion Polymer Cells Based on HRR curves Cylindrical cells: ~ 4-6 minutes Polymer cells: ~ 5-8 minutes Power tool packs: not discernable Nominal value: 5 minutes Time (s) Threshold values based on steady-state contribution from commodity, excluding Li-ion batteries Ditch, B., Yee G. and Chaos M., Estimating the Time-of-Involvement of Bulk Packed Lithium-Ion Batteries in a Warehouse Storage Fire, Fire Safety Science 11, 2014.

24 Convective Heat Release Rate (kw) FM Global A Timeline for Protection Suppression Time (s) 1. QR link 2. SR link 3. Batteries involved 4. Partial collapse 5. Fire fighting

25 Conclusions Initial fire growth similar for all commodities Dominated by carton material Battery involvement: Expected within 5 min after ignition Occurs after sprinkler operation Not observable for power tool packs Sprinklered fire tests needed with Li-ion batteries

26 Protection Recommendations Sprinkler protection recommendations, based on: Included in FM Global Technical Report Li-ion battery hazard assessment at sprinkler operation Commodities with analogous hazard characteristics, e.g., fire growth, projectiles, reignition, etc. Small format Li-ion batteries Cartoned in bulk storage

27 Disclaimer Unique test approach only used due to availability of Li-ion batteries Does not provide same information as Commodity Classification or sprinklered fire testing Protection recommendations may be amended with additional research specific to Li-ion battery hazard

28 Special Thanks to: Exponent, Inc. Property Insurance Research Group FM Global More Data at Search: lithium ion, FM Global