How to manage lithium-ion battery risk in production facilities
Lithium-ion batteries have become part of the fabric of modern manufacturing, powering the cordless tools, automated guided vehicles, forklifts and test equipment that keep a production line moving, and in a growing number of plants the batteries, or the products that contain them, are what the facility makes. That usefulness comes with a hazard that deserves respect, because a single failed cell can lead to a fierce, fast and stubborn fire. Drawing on the guidance published by the Fire Protection Association, of which we are a member, in particular its Need to Know Guide RE2 on lithium-ion battery use and storage, this article sets out how production facilities can manage that risk in a practical way.
Why production facilities carry particular risk
Several features of a production environment combine to raise the stakes. Batteries are often used, charged and stored in significant numbers, the charging that presents the highest fire risk may go on around the clock, and the surrounding plant, stock and work in progress represent a value that a fire can destroy in minutes. For manufacturers in the aerospace and defence sectors, which form a substantial part of the industrial base across our region, the importance of continuity and the sensitivity of the sites add further weight to getting this right, and the same is true for the automotive and electric vehicle plants where batteries are handled at scale. Whatever the sector, the principle holds, which is that the controls should be proportionate to the quantity of batteries and the way they are used.
How lithium-ion battery fires start
Most lithium-ion battery fires begin with thermal runaway, a chain reaction that takes hold when a cell generates more heat than it can dissipate. It can be triggered by mechanical damage such as piercing or dropping, by manufacturing defects or internal short circuits, by exposure to heat from an outside source, or by overcharging or over-discharging. Once it begins, the cell breaks down its own flammable electrolyte and releases a mix of gases, including hydrogen, carbon monoxide and highly corrosive hydrogen fluoride, which can ignite immediately or build up and then deflagrate if they meet a source of ignition. Because the reaction generates its own oxygen, these fires are very difficult to put out, and the greatest risk arises during charging, particularly where a cell is already defective. It is worth knowing that the flat pouch and prismatic cells common in many devices are more vulnerable to this kind of failure than the sturdier cylindrical and button formats.
Thermal runaway in a lithium-ion battery, showing how quickly a single cell can fail.
The key pointA lithium-ion fire generates its own oxygen and can reignite hours or even days later, so the priority is to prevent one starting rather than to rely on putting it out.
Controlling the risk in daily use
The Fire Protection Association sets out a set of basic controls that should apply wherever batteries are used, charged or stored, and they translate readily to a production setting:
- Buy from reputable manufacturers and suppliers, and charge only with the correct manufacturer or compatible charger for the specific cells or packs in use.
- Inspect batteries for damage before use, and take any that are damaged or defective out of service straight away.
- Avoid charging in unoccupied areas, and disconnect batteries once charging is complete rather than leaving them on charge indefinitely.
- Keep batteries away from conductive materials, from sharp objects that could puncture a cell, and from anything flammable or combustible.
- Use and store batteries in dry, reasonably cool and well-ventilated places, out of direct sunlight and away from sources of heat.
- When batteries are not in use, keep them in a purpose-made enclosure such as a metal battery cabinet or a fire-resisting safety bag.
- Provide smoke detection, ideally combined smoke and carbon monoxide detection, in the areas where batteries are handled and stored.
- Set out emergency procedures, and train staff specifically in how to deal with a damaged or faulty battery.
Storing batteries safely
Storage deserves separate thought, because a store holds concentrated energy in one place. The guidance recommends keeping stored batteries at a state of charge of no more than around 60%, since a lower charge reduces the likelihood of thermal runaway. Where modest, incidental quantities are kept in a sprinkler-protected area, the FPA guidance points to sensible limits such as holding the storage area to no more than 20 square metres, keeping the stack height below about 1.8 metres, and leaving aisles of at least 3 metres between separate storage areas. Larger or dedicated stores call for more, including storage rooms separated from the rest of the building by construction offering at least two hours' fire resistance, smoke and carbon monoxide detection throughout, and, for external storage, non-combustible containers set a safe distance from other buildings. The precise specification should be set by a competent person as part of the assessment, but the direction is clear, which is to limit quantities, control the charge, separate the store and detect a problem early.
If a battery overheats or catches fire
Lithium-ion fires do not fall neatly into a single fire class, and only suitably trained people should ever attempt to tackle one, and then only at the earliest stage and when it is safe to do so. Control relies on cooling, usually with generous amounts of water, to bring the temperature below the point of reignition. For small fires, specialist extinguishers using an aqueous vermiculite dispersion can be applied directly to the cells to cool them and starve them of oxygen, and although this type is not currently listed under BS 5306, it may be suitable as a first-aid measure for an incipient fire where the assessment supports it, staff are trained, and the equipment is serviced. Proprietary containment bags can help with a small device that is beginning to overheat but can still be handled safely. Larger arrays are a different matter, often needing the fire and rescue service to apply water for a long period, with cooling continued for hours or even days to prevent reignition, which is the clearest possible argument for designing the risk out wherever you can.
A demonstration of how dangerous it is to tackle a lithium-ion battery fire without training or the right equipment.
Handling damaged or defective cells
A damaged battery can retain stranded energy and stay dangerous, so any cell that is damaged or defective should be removed from use, handled with care and prepared for safe disposal. The guidance is to pack such cells in line with the carriage of dangerous goods regulations, encased in a non-combustible, non-conductive insulating material such as vermiculite, and to hold them apart from the working areas, in a room with two hours' fire resistance or a non-combustible external container set well away from buildings, until a licensed carrier removes them. Establishing a regular collection prevents a hazardous accumulation building up on site.
Where this fits in your fire risk assessment
The thread running through all of this is that lithium-ion batteries should be addressed explicitly in your fire risk assessment, which needs to cover their handling, storage, use and charging, and which must be carried out by a competent person. From there it connects to the wider arrangements on site, such as the fire doors and compartmentation that would contain a fire, the detection that would raise the alarm early, and the staff training that turns a written plan into the right actions on the day. In a building that also holds significant stored stock, it sits alongside the broader controls we describe on our warehouse fire safety page.
Supporting manufacturers across our region
We work with manufacturers and production facilities right across our region, which carries a deep base of advanced manufacturing, automotive and electric vehicle production, and aerospace and defence work. In the North West, that includes plants and industrial sites around Ellesmere Port, Crewe, Warrington, Manchester and Liverpool. Across North Wales, we support manufacturers in Deeside and Wrexham, and throughout Flintshire and Wrexham, where the region's aerospace cluster is concentrated. In the West Midlands, we work with production facilities in Telford and Shrewsbury.
Managing batteries in your facility?
If your production or manufacturing site uses, charges or stores lithium-ion batteries, we can help you assess and manage the risk in a practical, proportionate way, across the North West, North Wales and the West Midlands. To discuss your premises, please get in touch.
Get in touch Fire risk assessmentThis article is provided for general information and does not constitute legal advice or a fire risk assessment. It draws on guidance published by the Fire Protection Association and RISCAuthority, in particular Need to Know Guide RE2 on lithium-ion battery use and storage. Specific advice should be sought from a competent person for your own premises.