Often used in power tools, portable equipment and plant machinery, lithium-ion batteries, also known as Li-ion, can pose a serious safety risk if not stored, maintained and disposed of properly and with caution.
There is a difference between lithium and lithium-ion batteries. Lithium batteries are generally single use whereas lithium-ion batteries can be recharged and have a higher energy output. Often lithium-ion batteries do not have to be removed from the device it charges. Many personal electronic items which enter the workplace will contain lithium-ion batteries such as laptops, phones and cameras.
Risks of fire
Firstly, why are they used if there is a risk of fire?
Lithium-ion batteries are compact and lightweight, hold considerable energy for their size and perform well despite being regularly re-charged and discharged.
The risks of fires are generally caused by defective batteries, incorrect chargers and items being left on charge for too long. Third-party batteries which can be bought cheaply on the internet – and don’t always meet safety standards – are also to blame.
Storage of batteries can be a concern and should, wherever possible, be kept to a minimum number and kept in a fire-resistant container.
How to reduce the risk
Always follow the battery fire safety advice when charging your equipment:
- Avoid storing, using, or charging lithium-ion batteries at very high or low temperatures
- Don’t leave items continuously on charge after the charge cycle is complete, e.g., don’t leave your tools or equipment plugged in overnight
- Never cover chargers or charging devices
- When in transit, avoid keeping items containing lithium-ion batteries together
- Don’t overload your sockets
- Avoid fast charging an aged or low performing battery
- Stop using both the charge and battery if either rises more than 10ºC on a regular charge
- Avoid storing devices in places with high temperatures, such as a warm vehicle or a even a warm pocket.
Tell-tale signs of bad batteries
Warning signs that a lithium-ion battery pack or cell is likely to fail include:
- The battery appearing to bulge or swell
- Discharging too fast
- And/or the battery being hot to the touch.
Electric vehicles – risk of fire
Electric vehicles in the workplace are also subject to the same sorts of risk. Because of the risks, electric vehicles should be charged away from buildings and have a good separation between them, generally two metres, to reduce the risks of fire spread.
Warning – if involved in an accident
If an electric vehicle is involved in an impact, it is important that it is taken to a garage that is capable and proficient in dealing with cars with electric batteries, either fully EV or hybrid.
The vehicle will need to be stored outside and away from other vehicles until the stability of the battery is confirmed.
All work with an EV, or hybrid, requires the people involved to have a higher level of awareness and competence and should have completed specific training – which should be recorded and reviewed regularly as required by best practice or legislation.
With any ‘bad’ battery it should be removed from the product (where possible) and stored in a suitable fire-proof and sealed storage container. However, adding multiple ‘bad’ batteries together can greatly increase the risk of thermal runaway.
A real, and significant problem when it comes to an EV fire is in trying to put it out. Electric vehicle fires are known to reignite hours, days or even weeks after the initial event, and they can do so many times.
How lithium-ion batteries ignite
Once a battery fails or ‘runs away’ the cells usually start to give off smoke. Thermal runaway, the chemical process within the lithium-ion battery, produces heat and flammable toxic chemical gases very quickly, often before any flame appears.
It is important not to try to cool, or extinguish flames, with water as this can react with the toxic gases produced by the battery, which include; carbon monoxide, carbon dioxide, hydrogen fluoride, hydrogen chloride, sulphur dioxide, and multiple hydrocarbons – up to and including hydrogen cyanide.
The causes of thermal runaway can be numerous:
- Damage on impact
- Short circuit
Controlling a fire
This is a specialist operation and requires specialist extinguishers, or blankets, as this type of fire can spontaneously reignite several days later.
A lithium-ion battery fire blanket is designed for use on lithium-ion battery fires, although it may also be used as a precautionary measure whilst charging, transporting, or handling batteries and battery-operated devices.
AVD (Aqueous Vermiculite Dispersion) – a nontoxic and revolutionary extinguishing agent, is contained within each Lith-Ex extinguisher and is deployed as a mist. When sprayed over the battery, it then creates a film over the surface which instantly dries to cool down the flames, prevent reignition, and creates an oxygen barrier so that the fire burns itself out.
Disposal of lithium-ion batteries
Batteries should be collected by a professional waste management company, and regularly removed from the premises to avoid substantial accumulation. Lithium-ion batteries have been linked to hundreds of waste fires after being disposed of as standard household waste.
Many businesses in the hire industry rely on tools and equipment charged by lithium-ion batteries.
Advice from Risk Managers includes:
- Put in place reasonable fire safety precautions.
- Review and update existing fire risk assessments.
- Purchase specific fire extinguishers designed for use on fires involving lithium-ion batteries.