New technology, old solutions?

It is easy to forget just how ubiquitous lithium-ion rechargeable batteries are for a 21^st century lifestyle. From the smallest hearing aid to the ten tonne storage batteries in commercial and industrial facilities, they provide a large capacity electricity source in a relatively low weight and compact form, ideal for commercial, military and leisure uses.

But in the last few years there have been a growing number of serious incidents involving these batteries and lives have been lost or significant damage caused as a result. According to The Guardian newspaper, there have been at least 12 deaths and 190 injuries in the UK where e-bikes or e-scooters have been involved as the likely cause of the fire since 2020.

As with all new technologies, there are often teething problems and new sources of mass energy storage, such as lithium-ion battery plants, are unlikely to be fully implemented without problems. It is also worth remembering that prior to the advent of George Stephenson’s Rocket locomotive in 1829, it was believed that human beings travelling at more than 30 miles an hour would be asphyxiated as the air would be moving so fast breathing it in would be impossible!

Although there has been a continuing improvement in the safety of the batteries themselves, the sheer volume of numbers and ever-increasing applications being found, the seismic changes they have allowed (think laptop computers, mobile phones, electric cars, hearing aids the size of a fingertip), have changed everyone’s lives. Nevertheless, the new technology, developed in the 1970s and 1980s, has been offered commercially since 1991 and management of its risks has been evolving ever since.

Burgeoning Demand

The international market for lithium-ion batteries is around $56 billion in 2023 and is expected to reach around $187 billion by 2032, a compounded annual growth rate (CAGR) of 14 per cent, while in the UK the CAGR is predicted to be around 11 per cent, possibly as a result of being ahead in its historic large uptake of batteries and usage.

The use of such batteries includes the growing use of electric vehicles, encouraged by government to support the delivery of the “net zero” carbon targets by 2050 (or whatever the deadline is determined to be this week/month/year), personal mobility systems – e-scooters, e-bikes and mobility scooters, uninterrupted powers supplies, electric tools, solar energy storage etc.

The lithium-ion battery has a high energy density and low weight and is used in a wide variety of electronic devices. Another type is the lithium iron phosphate battery, used in electric vehicles, which has a greater stability and longer lifespan. These batteries are made up of four components: the cathode material such as lithium iron phosphate; the anode material where the lithium-ions are stored; the electrolyte through which the electricity flows and is made up of additives, solvents and salts; and the separator which isolates the anode and cathode from each other. Individual cells are small and are joined together to make “modules”. A small battery may have as few as ten cells. On the other hand a TESLA car battery contains around 7,000 cells.

The high energy density and relatively small size means that they are volatile when subjected to stresses such as damage from impact, crushing or penetration, incorrectly charging, overheating and product defects or malfunction. Disposal of batteries has come to the fore in the UK recently with a number of large fires attributed to batteries being disposed through recycled waste systems. The physical nature of recycling plants has led to a battery being crushed leading to overheating and an ignition of flammable electrolyte which spreads to other waste materials.

It has been estimated in 2021 by researchers that lithium-ion batteries cause around 48 per cent (201) of all waste fires and costs the economy around £158 million each year. In addition to these fires there are hundreds more caused by ignition of batteries in waste transport vehicles both while travelling or parked. Despite local and national campaigns to raise awareness of the risks posed by batteries inadvertently thrown away this does appear to be a growing issue of concern for recycling companies and waste site managers.

 

“While there have been deaths related to battery fires in mobility scooters, they are rare and are far outweighed by deaths associated with road use and in deliberate fires by arsonists”

 

Global Impact

The manufacture of lithium-ion batteries has not been without challenges and the industry was plagued by a series of fires across the globe in the early 90’s. Ultralife Batteries Ltd, one of the first industrial scale manufacturers, were particularly unlucky. Their Abingdon factory produced batteries for use in sea water equipment. It had a series of particularly destructive fires in September 1995 (loss of £145,000), and December 1996 (£3.5 million). At the time the cause of both fires were unknown but a further small fire was used to examine and identify the probable cause and mechanism for the rapid development of the fire. Forensic scientists, loss adjusters and fire investigators concluded that heating resulted from a defect in the battery which caused expansion of the electrolyte – this led to a leak from the battery as joints were split. Ignition by a short circuit ignited the flammable vapour that heated the next battery leading to a second leak that ignited.

In this particular instance, a factory technician was able to extinguish the fire which involved two batteries and permitted a detailed investigation. At the earlier fires, no one was in the vicinity before the fire had reached a thermal runaway stage. This led to a chain reaction which engulfed pallets of batteries with an estimated two minutes causing the significant interventions by the FRS.

As an industry, lithium-ion batteries production still has a high number of production facility fires, but given the increase in production since the 1990s, the rate of fires has decreased. The Ultralife Battery facility in Abingdon had a final moment of notoriety when an early morning fire broke out on June 5, 2004 as a ground floor store became fully involved in fire. Batteries blew up for over an hour. A firefighter was blown over by the force of one explosion, which also blew out the gable wall of the building.

E-vehicle Fires

Fires in vehicles and personal transportation systems have become more frequent during the last five years or so with the increased popularity of e-scooters and e-bikes. Mobility scooters have been available for nearly three decades and there have been challenges, in regard to them blocking the means of escape in buildings. This is especially where the owners are recharging the batteries with the vehicles “parked” in common areas such as corridors in blocks of flats and multi-occupied buildings. The vehicle is also capable of obstructing egress, particularly from flats with only one access/egress point.

While there have been deaths related to battery fires in mobility scooters, they are rare and are far outweighed by deaths associated with road use and in deliberate fires by arsonists. While mobility scooters give those with some mobility issues a new freedom, greatly enhancing quality of life. The introduction of cheap individual scooters for as little as £299 and e-bikes from £399 have revolutionised personal transport giving motorised transportation to groups of society otherwise excluded due to financial and/or geographical (rural or no bus routes available) reasons. Unfortunately, it appears that as with many other things in life, you get what you pay for and there have been a growing number of serious fires caused by batteries in e-scooters, sometimes causing deaths as batteries to explode and trap occupants, again, particularly in properties with limited egress. Most often the fires start when batteries are being charged and there have been claims that this is mainly due to substandard or modified products.

London Fire Brigade attended 37 e-bike and e-scooter fires to the end of March 2023, a 60 per cent increase on the same period in 2022 and said that it appeared that cheaper, possibly defective batteries purchased from online sources may not comply with UK safety regulations and are “more likely to fail and present an increased fire safety risk”. There are also concerns about conversion kits which upgrade normal bicycles to e-bikes.

Incompatibility between batteries and charging units has also become seen as another critical failing with Adam Smith, Inner North London Assistant Coroner, issuing a Regulation 28 report to prevent future deaths after the ninth death in six fires in one year attributed to faulty lithium-ion batteries. At this incident, the victim died when a faulty battery on one of several e-bikes within an overcrowded flat used by several food couriers ignited. Incompatibility between battery and charger led to the thermal runaway and failure of the battery. The report demanded that action should be taken to prevent future deaths and asked the Office for Product Safety and Standards (OPSS), part of the Department of Business and Trade, to use their powers to do so.

The government has said that research was being undertaken by the University of Warwick and will report before changes to regulations. The charity Electrical Safety First (ESF) has been campaigning on this issue for some time and the report Battery Breakdown: Why are e-scooter and e-bike batteries exploding in people’s homes and what can be done about it? is available at (https://www.electricalsafetyfirst.org.uk/media/sgyikuwb/esf_batterybreakdown_report_2023_v7_-final.pdf). It is an essential read for those tackling what appears to be a growing risk in all communities. The National Fire Chiefs Council has produced a guide to safe practice with regard to charging, storage and buying e-bikes and e-scooters and warns against purchases from disreputable or unverified sources, particularly online where standards may be compromised or not complied with.

 

“The number of fires involving electric cars are disproportionately low with some experts insisting that ordinary car fires are likely to occur 4.5 times more frequently”

Fires in Aircrafts

The universal presence of lithium-ion batteries means that there is virtually no form of transport that is not reliant on these powerful energy sources. Unsurprisingly, there has been fires in aircraft caused by failures of the lithium-ion battery packs. On July 12, 2013 a parked Boeing 787 Dreamliner of Ethiopian National Carrier caught fire at Heathrow just one week after the international fleet of 787s had  been brought back into service having previously been grounded because of battery malfunctions. The Air Accident Investigation Branch (AAIB) studied the events and concluded the fire was in the location of the emergency locator transmitter (ELT). The fire on the aircraft was initiated by a release of stored energy from the lithium-ion battery within the ELT module. Battery wires had crossed and become trapped under the battery compartment cover plate, damaged its insulation and created a short circuit which allowed the rapid uncontrolled discharge of the battery. The compromised seal on the battery cover plate allowed flames to impinge directly on the composite structure of the aircraft, and this led to a fire in the rear fuselage crown. The fire spread as other materials caught fire, including the resin in the composite material which allowed the fire to continue, even when the battery energy was exhausted.

After further research, Boeing installed more insulation between individual battery cells and a new steel box to contain any potential fire. As ever, the continuous improvement processes of the international aviation industry have built on the lessons of this failure and reduced the risk of this event occurring again.

Wembley Blaze

If problems with batteries in aircraft seem a little remote from everyday life then a fire in Wembley in 2022 brings things a little closer to home for most of us. On the hottest day of the year so far, July 19 – you may have missed this incident due to the numerous wildfires and major incidents that were being declared across the UK – a BMW 3i caught fire in a car park and spread, eventually destroying eight business, some of which had to have parts of the buildings damaged. The cause of the fire was put down to an ‘unknown fault within the battery system’ by the LFB investigators.

Fires involving electric cars have generated a disproportionately high level of media interest in recent years. Stories of fires being unextinguishable are common, but in fact the number of fires involving electric cars are disproportionately low, with some experts insisting that ordinary car fires are likely to occur 4.5 times more frequently than those in electric vehicles ,according to the automotive research centre in Thatcham, Berkshire. It may be because electric cars are less common and generally newer than the majority of other types of cars using diesel and petrol.

Extinguishing Methods

Extinction of electric car fires can be more complex than other vehicle types but generally large volumes of water to cool the battery pack is still the most cost-effective way to extinguish the fire. Unfortunately, the fire can restart when the battery packs dry out, but by that time a strategy to permanently extinguish the fire and remove the vehicle should have been arranged. Other techniques include the use of fire blankets to suppress flames and using breathing apparatus allowing crews to attack the fire in a traditional approach.

Other, alternative techniques such as suffocating the fire with inert gases are problematic – wind, eddy currents etc – and will be unsuccessful as the fire does not require oxygen. Separation of the unaffected cells will reduce the risk of a wider thermal runaway.

Once the fire is out, removal of the vehicle will remain a hazardous activity and often fire and rescue teams will escort a damaged car on a trailer to the scrapyard to ensure no further fires occur. A ‘fail safe solution’ would be to submerge the vehicle in water, but the pollution impact is something that needs consideration before attempting this, and submersion in sea water is not recommended as the reaction with lithium-ion will produce chlorine gas!

Paul Christensen, Professor of Pure and Applied Electrochemistry at Newcastle University, said: “We don’t need to be worried about the small incidence of fires involving electric vehicles, but we do need to be aware. A lithium-ion battery stores a huge amount of energy in a very small space. Since 2008, the adoption of such batteries has outstripped our appreciation of their risks. We’re running to catch up, but we will do,” he concludes.

Increasing Demand

Looking to the future, the “net zero” initiative/commitment will lead to an increase in demand for the larger battery storage “repositories” where excess electrical energy for solar, wind or nuclear sources can be held until required. There are already nearly 40 such sites in the UK with another 400 planned for the next year or so. Moves are now afoot to make FRS approval conditional for the location of plants which are believed to be of relatively high fire risk.

With the changing energy footprint in the UK, we are faced with many challenges ahead. Many are not new – lithium-ion batteries have been in use for over 30 years but only now are we coming to terms with some of the issues and consequences to their adoption. Electricity storage plants are a fact and for the FRS, at least, planning for the consequences of fires and other incidents is an essential and not a “would like to do”. The learning is already there in most cases and taking a strategic perspective rather than a “wait and see” approach should mean approaches will be anticipated and thought through so that “knee-jerk” reactions, particularly at national and governmental levels, are not required having already developed the foresight to make emergencies solvable and not become wicked problems.

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