SAFER CITIZENS THROUGH SKILLED FIREFIGHTERS FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018 Battery technology – past, present and future
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SAFER CITIZENS THROUGH SKILLED FIREFIGHTERS
FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018
Battery technology – past, present and future
SAFER CITIZENS THROUGH SKILLED FIREFIGHTERS
FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018
The Past
SAFER CITIZENS THROUGH SKILLED FIREFIGHTERS
What are batteries?
• What is a battery and cell? • A cell is a single unit that converts chemical energy into electrical
energy. • A battery is a combination of cells
• What is a primary and secondary battery? • A primary cell or battery is using a chemistry that can not be
“recharged” – single use/disposable • A secondary cell or battery is using chemistry that can be
“recharged”
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Example of cells are galvanic cell, Daniel cell, Leclanche cell Examples of batteries are lead-acid battery, lithium-ion battery, magnesium ion battery Primary cells include lithium metal and many zinc based chemistries (alkaline was primary until rechargeable developed in 1990s) Secondary include lithium ion, lead acid (lithium metal are being developed to be rechargeable)
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Daniell cell (1836)
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Example of cells are galvanic cell, Daniell cell, Leclanche cell Examples of batteries are lead-acid battery, lithium-ion battery, magnesium ion battery Primary cells include lithium metal and many zinc based chemistries (alkaline was primary until rechargeable developed in 1990s) Secondary include lithium ion, lead acid (lithium metal are being developed to be rechargeable)
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What types are there and where are they used?
• Lead-acid • Nickel-cadmium (NiCd) • Nickel metal hydride (NiMH) • Lithium metal • Lithium ion • Lithium air • Lithium sulfur
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Lead-acid
• Lead electrodes (PbO2 & Pb) • Sulfuric acid electrolyte (approx. 30% soln) • Rechargeable • Low energy density • High surge current • Low cost
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More comment on hazards – corrosive put also heavy metal
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Lithium
• Soft, malleable metal • Pyrophoric (ignites in air) • Normally stored under oil to protect it • Metal will burn • Flame temp ~1000 °C • Reacts violently with water
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Explain connection with lithium, potassium and sodium
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Lithium metal
• Wide range of chemistries • Most common is Li/MnO2 • Lithium metal electrode • Flammable electrolyte
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Change image
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Lithium ion
• Most common systems: • LiMnO2 / Graphite • LiCoO2 / Graphite • No metallic lithium! • Flammable electrolyte
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Bit more focus on no metallic lithium.
SAFER CITIZENS THROUGH SKILLED FIREFIGHTERS
FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018
• Shutdown seperator • Cell vent or tear away tab • Current interrupt device (CID) • Positive temperature coefficient (PTC) • Current limiting fuses • Diodes • Battery management system (BMS)
• Failure rate estimated at 1 in 10 million for lithium ion battery cells • Typical EV has 80 – 100 cells (BMW i3) but others may contain 7,000 cells (Tesla S).
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Governed by IEC 62133 Battery packs using Li-ion require a mandatory protection circuit to assure safety under (almost) all circumstances. Governed by IEC 62133, the safety of Li-ion cell or packs begins by including some or all of the following safeguards. Built-in PTC (positive temperature coefficient) protects against current surges. CID (circuit interrupt device) opens the circuit at a cell pressure of 1,000kPa (145psi). Safety vent releases gases on excessive pressure buildup at 3,000kPa (450psi). Separator inhibits ion-flow by melting process when exceeding a certain temperature threshold.�(See BU-306: What is the Function of the Separator?) The PTC and CID work well in a smaller 2- or 3-cell pack with serial and parallel configuration, however, these safety devices are often omitted in larger multi-cell batteries, such as those for power tools, because the shutdown can occur in a cascade format. (See BU-302: Series and Parallel Battery Configurations) While some cells may go offline early, the load current causes excess current on the remaining cells. Such overload condition could lead to a thermal runaway before the remaining safety devices activate.��In addition to internal cell safeguards, an external electronic protection circuit prevents any cell from exceeding 4.30V on charge. In addition, a fuse cuts the current if the skin temperature of any cell approaches 90°C (194°F). To prevent the battery from over-discharging, a control circuit cuts off the current path at about 2.20V/cell.��Each cell in a string needs independent voltage monitoring. The higher the cell count, the more complex the protection circuit becomes. Four cells in series had been the practical limit for consumer applications. Today, off-the-shelf chips also accommodate 5–7, 7–10 and 13 cells in series. For specialty applications, such as the hybrid or electric vehicle delivering several hundred volts, specialty protection circuits are made. Monitoring two or more cells in parallel to get higher current is less critical than controlling the voltage in a string configuration.��Protection circuits can only shield abuse from the outside, such as an electrical short or faulty charger. If, however, a defect occurs within the cell, such as a contamination of microscopic metal particles, the external protection circuit has little effect and cannot arrest the reaction. Reinforced and self-healing separators are being developed for cells used in electric powertrains, but this makes the batteries large and expensive.��Li-ion commonly discharges to 3.0V/cell. The lowest permitted “low-voltage” power cut-off is 2.5V/cell. It is not advised to keep the battery at that level as self-discharge could bring the cell to its cut-off voltage, causing the battery to go into sleep mode. Most chargers ignore Li-ion packs that have gone to sleep and a charge is no longer possible. (See BU-808a: How to Awaken Sleeping Li-ion.)��In the ON position, the internal protection circuit has a resistance of 50–100mOhm, lower on power packs. The circuit typically consists of two switches connected in series; one is responsible for the high cut-off, and the other for the low cut-off. Larger packs need a more careful design than a smaller battery, and single cell packs for mobile phones and tablets get away with a voltage and current limit in addition to some intrinsic cell protection. (See BU-802a: How does Rising Internal Resistance affect Performance?)��Some low-cost consumer chargers may rely solely on the battery’s protection circuit to terminate the charge. Redundancy is paramount for safety, and unknowingly to the buyer, low-cost consumer chargers may be offered that do not have properly functioning charge algorithms. This could be a vehicular charger for a mobile phone or an e-cigarette.��A further concern arises if static electricity has destroyed the battery’s protection circuit. A shorted solid-state switch is permanently fused in the ON position without the user knowing. A battery with a faulty protection circuit functions normally but it fails to provide protection. The cell voltage could rise above a safe level and overcharge the battery. Heat buildup and bulging are early signs of malfunction, but some batteries explode without warning.��Low prices make products from Asia attractive, but safety standards my not be equal to those in branded products. A wise shopper spends a little more money and buys recognized brands. (See BU-809a: What Everyone Should Know about Aftermarket Batteries.)� �Manufacturers of lithium-ion batteries do not mention the word “explosion” but refer to “venting with flame” or “rapid disassembly.” Although seen as a slower and more controlled process than explosion, venting with flame or rapid disassembly can nevertheless be violent and inflict injury to those in close proximity.� Simple Guidelines for Using Lithium-ion Batteries Exercise caution when handling and testing lithium-ion batteries. Do not short-circuit, overcharge, crush, drop, mutilate, penetrate with foreign objects, apply reverse polarity, expose to high temperature or disassemble packs and cells. Use only lithium-ion cells with a designated protection circuit and approved charger. Discontinue using the battery and/or charger if the pack temperature rises more than 10ºC (18ºF) on a regular charge. The electrolyte is highly flammable and battery rupture can cause physical injury. Use a foam extinguisher, CO2, dry chemical, powdered graphite, copper powder or soda (sodium carbonate) to extinguish a lithium-ion fire. Only pour water to prevent the fire from spreading. If the fire of a burning lithium-ion battery cannot be extinguished, allow the pack to burn out on its own in a controlled and safe manner.
Doughty, Dan; Roth, E. Peter. "A General Discussion of Li Ion Battery Safety" (PDF). The Electrochemical Society Interface (Summer 2012).
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Presentatienotities
In Fig. 3, an external source of heat (that simulates an abuse event) is used to raise the temperature of the cell to the Onset Temperature, T(onset). A practical definition of T(onset) is typically a self-heating rate of 0.2°C/min. for thermal ramp experiment. (ARC sensitivity is 0.02°C/min., an order of magnitude more sensitive.) This low heat generation can usually be accommodated and dissipated in the battery packs. Increased reactivity is a consequence of SEI decomposition, exposing the reactive anode to the self-heating reactions involving the electrolyte.9 If this heat is not dissipated, the temperature will continue to rise due to sustained exothermic reactions. The region above the onset temperature is denoted as stage 2 (acceleration), which is characterized by more rapid and accelerating heat release. Stage 2 results from increased electrolyte reduction at the anode due to continuing loss of the SEI and to onset of electrolyte oxidation at the active cathode surface. These reactions depend on the active material chemistries and state of charge. Venting and release of smoke may occur during stage two. Additional heating causes the cell to enter Stage 3 (runaway), in which the high-rate cathode and/or anode reactions cause temperature to rise rapidly (thermal runaway) and flame or rapid disassembly may follow. Thermal runaway is loosely defined as a self-heating rate of 10°C/min or greater. At this self-heating rate, it is highly unlikely that any intervention or external cooling mechanism could quench the ensuing thermal runaway. Runaway temperature, T(runaway), is a strong function of cell size, cell design, and materials in the cell. T(runaway) can vary from 130°C to well over 200°C in lithium ion cells. Cathode materials that release oxygen at high temperatures have especially high reaction rates and reaction enthalpies. The timing of thermal runaway can be delayed by minutes or several hours or days, since it depends on particulars of construction of the battery pack and the operating environment. Incubation time of hours has been observed in accidents investigated by the U.S. Dept. of Transportation (DOT).11 Events such as these have resulted in DOT banning shipment of lithium batteries on passenger aircraft.12 Accurate and easy-touse thermal abuse models of modules and packs would be a tremendous benefit in understanding the thermal environment of cells and packs under off-normal conditions
Emission data from a complete vehicle fire is scarce. Lönnermark and Blomqvist6 have made measurements both on a full scale fire and parts of a vehicle like door panels, dashboard etc. The vehicle tested in the full scale fire was a medium class model from 1998. No HF could be detected in these tests either in the small-scale tests or in the full scale test but significant amounts of HCN (NGV 1.8 ppm, TGV 3.6 ppm), HCl (TGV 5 ppm) and SO2 (NGV 2 ppm, TGV 5ppm). Recently Lecocq, Bertana, Truchot and Mairlair reported emission data from both a fullscale fire of a fully charged Electric Vehicle (EV) and a full-scale fire of a similar Diesel vehicle fully gassed. This showed an initial peak of HF produced for both vehicles. This peak was higher than the amount of HF produced later in the fire stage when the battery started to burn in the EV but the amount of HF produced by EVs were at least twice the amount from the Diesel vehicles. The amounts reported are presented in Table. The initial HF peak might have been caused by the AC liquid. The battery cells tested in this study were power optimized cells that one could find in a plug-in hybrid electric vehicle (PHEV). A typical PHEV could have 432 cells (9.7 kWh, 345.6 VDC nom, 108s4p, cell: 7Ah, 3.2 V nominal). This means that the emissions reported in the battery cell tests should be multiplied with a factor of 432/5 = 86.4 to reflect a case where the complete battery is consumed in a fire. This results in a value of 400-1200 g HF depending on SOC with a low value for a high SOC. This is in the same order of magnitude as the valued reported by Leqoqc et. al. (657 and 919 respectively) as presented in Table 18.
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How do we recognise different vehicles?
Sourced from Hyundai Ioniq emergency response guides available at NFPA: https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Response-Guides/
• Sources that may assist with identifying an AFV include:
• The driver or passengers • Information gathered by the fire control room • Vehicle markings, such as the use of the term 'hybrid' • Bright orange cabling • Information stored on systems such as mobile data terminals (MDT) • Vehicle documents or handbooks
DVLA holds information on fuel type in UK but need identifying marks from vehicle involved.
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Electric Vehicles
Sourced from Tesla S 2016+ emergency response guides: https://www.tesla.com/firstresponders
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Presentatienotities
High voltage electrical equipment present Diagram from TESLA – most manufacturers produce emergency response advice like this but it isn’t standardised/ Shouldn’t cut until isolated but isolation can vary from vehicle to vehicle Normally manufacturer specific guides are freely available on line NFPA provides general guidance document which details all of the vehicles available on the American market and how to turn them off BUT American vehicles are named slightly differently to UK equivalents.
Cut away of the chassis of a lithium ion battery powered vehicle showing battery bank, which is held in an armoured compartment under the floor of the vehicle. Battery packs in cars are difficult to access and well sealed to prevent ingress of water. It is therefore difficult to put fire out and can keep causing re-ignition of fire (can control structure and interior but can’t get to source)
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Examples of EV incidents
• October 2013 – EV caught fire after hitting metal debris in the USA.
• March 2017 – EV caught light at charging station in China.
• October 2017 – EV caught fire in Austria after hitting concrete barrier.
• December 2017 – EV caught fire in Germany and was ultimately immersed in water.
• March 2018 – EV caught fire whilst charging in Thailand.
• May 2018 – EV drove off road in USA hitting concrete wall.
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Example of this from Seattle – head on collision an off ramp behind Recommendation from manufacturer to let vehicle burn – this would consume the most hazardous material in the fire, have less environmental impact (both plume and run-off) Tried to extinguish vehicle but kept reigniting for reasons discussed Actually decided to puncture battery bay and flood with water to bring to conclusion Spike of fire axe into armoured compartment full of this type of battery – wisdom????
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Electric Vehicles
Electrical hazard – isolate
Batteries inaccessible
Safe to use water
Battery fires difficult to extinguish & can reignite
Contaminated run-off
Consider a controlled burn
EV operational advice
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FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018
Mobile batteries – reputable batteries and engineering defects that were causing issues. Reengineered so batteries no longer overcharged. Cargo flights – why are flights are specifically causing issues.
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787 APU Fire
• Auxiliary power unit (APU) • Two incidents within days in 2013. • NTSB accident investigation:
• Lorry carrying 26 tonnes of batteries in 40ft container.
• Crashes off bridge onto A12 at rush hour. • Batteries caught fire. • Unsafe to commit crews into the container. • Recovery operations undertaken after midnight. • Next morning batteries reigniting. • 27 hours to remove vehicle to safe site.
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Can we use images from incident in public domain for case study?
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FIRE, RESCUE & NEW CHALLENGES SEMINAR NOVEMBER 9-10 2018
The Future
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Large Scale
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Problem with renewable energy – supply not constant Energy industry going towards energy storage rather than dumping into grid at periods of low consumption
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Large Scale
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Battery farms have their own air con and fire suppression Solar farm Each shipping container could contain up to 48 x 20kg lithium ion batteries (although battery technology will vary)
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Large Scale
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Also in warehouses – gives an idea of scaled required Have started catching fire
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Large Scale
First Wind Hawaii Grid storage facility - 12,000 lead acid batteries 3 separate fires: 1. Burnt out. 2. Burnt out. 3. Destroyed the battery
facility.
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Fires caused by dodgy transformers Transformers taking power from large wind turbine 3rd fire spread to facility as assumed it would burn out First Wind Hawaii Previous fires had burnt out without serious damage. Company had stockpiled dry agent. Honolulu County Fire Department arrived to find established fire. Dry agent was ineffective at this stage. Unsafe to commit crews into building. Fought defensively, prevented fire from spreading. Used waterjets to contain fire but did not direct them at the fire to avoid runoff and electrocution risk. Requested bulk CO2 but found it was ineffective. Active fire for 13 hours, 36 hours to be fully extinguished. Resulted in $30 million of damage to facility and bankrupted the inverter’s manufacturer.
• Large number of cells will be in circulation in coming decades. • Battery technology is evolving although lithium expected to be used into 2030s. • Lithium metal batteries may become mainstream due to advantages. • Manufacturing quality control important to keep failure rate low. • Increased spread of energy storage and electric vehicles. • Second use applications after EV being evaluated. • Waste and recycling could pose future challenges to emergency services.
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Mention added risk of spread of EV. Identifying EV and where batteries are as well as isolating power source.
