As the UK moves closer to decarbonise its energy grid and infrastructure, we will likely come to rely more and more on Lithium-Ion battery technology for efficient energy storage.
We already use this technology in many items, such as vehicles, power tools, domestic appliances and technologies including mobile phones.
When used as intended, on a day-to-day basis, these batteries do not present a significant risk to the user. However, they do contain flammable components which can cause runaway reactions.
A thermal runaway reaction occurs when, at elevated temperatures, decomposition of the battery cell materials and metals inside starts to occur. Eventually, this can lead to the battery self-heating.
If the battery self-heats more rapidly than the heat can dissipate into the surrounding area, then the temperature rises exponentially causing the battery to lose its structural integrity. This in turn releases the energy (and the fire) into the areas surrounding the battery allowing it to spread. Quite often the release of energy is so violent that the battery will explode.
The most common causes of thermal runaway in these batteries are from:
- Manufacturing defects
- Physical damage
These triggers may cause damage on an individual basis (such as a phone battery catching fire) but can cause greater issues when these devices and batteries are stored on mass. Unfortunately, there have been recent cases where such fires have occurred.
Therefore, there are important factors to consider within your workplace in relation to Lithium-Ion batteries, we’ve included some of them below.
Make sure you have an up-to-date fire risk assessment that covers the use and storage of Lithium-Ion Batteries and that it’s been conducted by a competent person. Be honest with the assessor and draw their attention to any storage facilities you may have – if they are stored within crates, it may not be immediately obvious, and you may miss out on vital knowledge.
You may also need to consider stock you hold –on your behalf or on behalf of your clients – because if you’re, for example, a freight/distribution company you may well be processing these items without realising the risk.
If your fire risk assessment is out of date, or if you’ve recently introduced new processes or equipment reliant on Lithium-Ion Batteries, we recommend having it reviewed to make sure these risks are captured and that suitable controls are implemented.
If your fire risk assessment indicates that you need to implement additional control measures to prevent a Lithium-Ion battery fire, it’s critical you implement these additional control and record them on your fire risk assessment.
You may also be required to liaise with your local fire and rescue service in order to coordinate a response with them.
Storage and use requirements
Make sure that you follow the manufacturers’ guidelines when storing Lithium-Ion batteries. Wherever possible, ensure that the batteries are protected from:
- Physical damage: such as strikes, being dropped, pierced or crushed
- Extreme temperatures: avoid them becoming overheated or plunged into excessive cold (refer to individual manufacturers storage requirements)
- Over-charging: try to prevent batteries from becoming over-charged, connected to the wrong charger or otherwise short-circuited
We also recommend regular visual inspections to ensure that damaged batteries aren’t used.
It’s sensible to leave gaps around significant quantities of batteries so that in the event of thermal runaway, the fire is less likely to spread to other batteries, preferably storing them within a designated, fire-resistant compartment or container.
Some batteries will give off gases and vapours when charged, so you need to make sure that suitable levels of ventilation are in place. The HSE’s guide ‘INDG139 – Using Electrical Storage Batteries Safely’ offers guidelines on how to do this.
Emergency procedures should be an essential part of any workplace to ensure that your workers know what to do should the unexpected happen.
The main objective is to respond quickly and effectively to emergencies so that incidents are managed, and lives are saved.
The level of detail and cover necessary within your workplace should be covered within your Fire Risk Assessment. However, where Lithium-Ion batteries are stored and used in significant quantities, it’s essential that documented response procedures are written, communicated to staff with regular training and drills undertaken.
It’s also recommended that you install extinguishers capable of suppressing Lithium-Ion battery fires. These should only be used to aid escape and not to otherwise tackle fires.
Aqueous Vermiculite Dispersion (AVD) fire extinguishing agent is recommended for use on Lithium-Ion batteries.
This new technology is an aqueous dispersion of chemically exfoliated vermiculite. It’s applied to lithium battery fires as a mist, extinguishing them and preventing the spread of the fire.
The vermiculite particles within the mist are deposited on the surface of the burning fuel to create a film over the top of the fire. This film instantly dries, and the particles bind together to form a non-flammable oxygen barrier between the fuel and the atmosphere.
This process also has a cooling effect on the fuel source and, as the water content in the extinguisher is evaporated, the vermiculite layer begins to build up and the fire is brought under control.
It will extinguish uncontrollable flames, quickly cool the excessive heat and prevent reignition, something that an ABC powder extinguisher or other liquid-based extinguishers will not be able to do on a Lithium-ion battery fire and so should be considered.