An explosive fire in a Lithium-Ion battery
In June 2018, a client of ours experienced an explosive fire in a Lithium-Ion battery used for a custom-built electric bike. The owner of the bike was about to show the battery to his family when it suddenly caught fire lying on the kitchen table! The battery was not connected, neither to the charger nor to the bike.
The fierce fire, experienced by our client as being like fireworks, could not be extinguished, and the fire spread to the interior and the building structure, causing a near total loss of the building.
Our own investigators have done technical studies of the damaged battery and the battery cells. The probable root cause of the fire is physical damage to the battery, causing thermal runaway in the battery. The built-up pressure was released through cracks in the first battery cell affected, causing thermal runaway in some of the other cells.
Fire statistics trends
Is there an increased risk of fire in introducing all these devices into our homes and workplaces? Our statistics do not show any clear trends, considering the enormous number of units. We receive fire claims caused by batteries in or charging for flashlights, electric bikes, drones, radios, and even children’s toys. But still the ‘normal’ root causes, such as electrical faults, not following safety manuals, oil fires, and hot work, are much more common sources of fire.
Looking across the Atlantic to the US, interesting stories unfold. During the past few years, up until 2017, more than 500.000 hoverboards were recalled after at least 99 reported events of smoking, fire, or explosions in devices, according to the Consumer Product Safety Commission. After introducing strict guidelines for approving batteries for hoverboards, the problem seems to have nearly disappeared in that market.
Electric cars are seldom the centre of attention related to battery fires, but there have been some examples of wrecked cars with heavy damage to the battery pack causing thermal runaway and fire. Not only can the batteries form a fire risk. In the case of electric cars, even though they have several built-in safety barriers in their battery and charging systems, the use of so-called emergency chargers in regular sockets can lead to overvoltage and fire in electrical switchboards or in sockets.
Remember the power needed to charge such large batteries might often create much larger resistance in the circuits than they were originally built for. Correctly dimensioned over-voltage protection must be fitted, alongside the use of fuses that are adequate for such charging.
Taking a step back, given all the devices on the market, the number of fire incidents is not very high. The problem is the fierce fire experienced, just as in our client case mentioned above. A Li-Ion fire is difficult to fight due to the chemical reaction continuously creating oxygen.
Mitigating fire risk
There are several mitigating actions taken by battery suppliers to prevent fire from occurring. As Helge Weydal Larsen explains, there would normally be built-in surveillance of charging and battery status. An X-ray of all batteries, to ensure the electrolytes are not polluted, is a precaution used by serious battery producers. Power tools are often considerably better protected from external impact and damage than regular consumer goods.
Why is all this important information for industrial businesses?
During our client visits, we often come across private devices such as radios brought to the workplace, power banks, and e-cigarettes.
A common recommendation issued in loss prevention reports is that the employer must keep track of these devices. Private electric and chargeable devices should be inspected and approved before allowing employees to bring them to work, regardless of the power source.
Means of getting around
In the larger industrial estates and warehouses, we can often find employees using kick-scooters to cover large distances rather than walking on foot. Introducing electric kick-scooters or fat scooters might be even more tempting. However, be aware that this might introduce a new fire hazard to the company. Tests done by our investigators clearly show that physical damage to battery packs might start a thermal runaway in the battery and consequently a fire. Rough handling of scooters at the workplace can therefore, in a worst-case scenario, cause injury to personnel or a fierce fire.
With the introduction of large battery banks storing power from PV panels for later use, a new fire risk can occur. These banks should be stored in separate fire compartments and protected with proper extinguishing systems, or preferably located an adequate distance from the production buildings. This could be the difference between an isolated battery fire and total damage of the location.
Better battery safety
Make sure the batteries used in your business are of high quality and approved according to relevant standards.
- Inform all employees of the possible fire hazard. This is also good employee policy, caring for their safety.
- Do not allow employees to bring personal Li-Ion devices to the workplace without approval.
- Ensure charging is done in a safe manner, and ensure that electrical systems are properly dimensioned.
- We recommend that charging is only done on a non-combustible base, away from any storage, and in areas with properly fitted smoke detection.
- Make sure that devices exposed to rough handling and damage are inspected. Greater than usual heating of the device when charging or during use is a sign that something is wrong.
- Make sure connections are properly fitted and undamaged, to prevent electric arcs.
- Follow airline regulations for transporting and handling battery-powered devices when travelling.