Cargo Ship Fires: How Safe Are Electric Vehicle Batteries?
15-08-2023 | By Robin Mitchell
Recently, a large cargo vessel caught fire off the Netherlands coast and is widely believed to have been caused by an EV battery. What exactly happened on the boat? Is this the first time that Lithium-based batteries have caused massive fires, and is this further evidence against their use?
Maritime Mishap: A cargo ship engulfed in flames at sea.
Cargo Ship Ablaze – Possibly EV Source
Last week, a large cargo ship caught fire while off the coast of the Netherlands, and a massive salvage operation has been undertaken to save the ship and its contents. At the time of writing, there have been no reports of a successful mission or even putting out the fire, indicating that efforts are still underway. The ship, which is around 27km north of Ameland Island, is believed to contain around 3,500 vehicles, of which 500 are electric. However, reports from the Dutch Coastguard have stated that only 25 are electric.
However, recent reports from Electrek suggest that the media might be misreporting the cause of the fire. The Dutch Coast Guard has not officially confirmed the source of the fire, and it's crucial to differentiate between confirmed facts and speculations.
Regardless of whether there are 500 or 25 EVs onboard, one fact that remains almost certain is that the fire on the ship was caused by one of the EVs. According to a radio transmission released by RTL, one of the crew members can be heard stating that the first started in one of the EVs batteries. As it is likely that the EVs were positioned next to each other, it wouldn’t take long for such a fire to spread uncontrollably and be virtually impossible to put out with typical fire-suppression systems.
While most of the crew were able to escape, it is believed that one died in the fire, with some of the crew jumping almost 30 meters into the water to escape the blaze. Furthermore, authorities are concerned that the sinking of the vessel could do harm to nearby migratory birds.
But if we ignore the mating rituals of migratory birds for a moment, this fire demonstrates a growing concern surrounding large lithium storage systems; flammability. While it may be the least reactive alkali metal, Lithium is notorious for its catastrophic nature when used in batteries, and it doesn’t take much to upset such batteries.
Any internal shorting of a Li-based battery will lead to a runaway cycle whereby the high current results in a temperature increase which further degrades the battery resulting in more current flow. As both the contents of lithium batteries and the gasses released during failure are highly flammable, such batteries can quickly turn into a pool of molten destruction, burning and melting anything it touches.
In the case of the cargo ship, batteries used in EVs have to be large, able to store as much 100kWh of energy, and such a massive amount of energy has the capacity to cause immeasurable damage. To make matters worse, unlike traditional fires, which can easily be put out with water, lithium fires can initially be doused with large volumes of water but then reignite hours afterwards. This has led to some firefighting forces turning to specialised containers that can be packed with sand to prevent a burning vehicle from reignition.
While protection methods can be integrated into lithium batteries, such as charge protection circuits, and overvoltage/overcurrent detection, nothing can protect against physical damage to a battery. Once two electrodes are shorted, either internally or externally, there is very little that can be done.
Have such fires happened before?
This fire is only one of many that have occurred since Lithium became a dominant battery technology. Everything from small cellular devices to vehicles has suffered from the consequences of using Lithium.
For example, a recent fire in the UK caused by an e-bike battery resulted in the deaths of a woman and two children. It is likely that the fire started overnight when the battery was being charged, and the ferocity of such batteries during failure would have made early warning extremely challenging.
Another demonstration of Lithium’s catastrophic capabilities was the failure of multiple Tesla Megapacks. These facilities were constructed to demonstrate the capability of lithium systems to store vast amounts of energy during peak production from renewable sources and then source the energy back into the grid during high demand.
However, it didn’t take long for fires to start at these facilities due to the massive amounts of energy stored and vast quantities of lithium metal in the batteries. Fortunately, no one was harmed in these incidences, but the large quantity of toxic materials spread into the local environment posed a serious health risk to those nearby.
Do such fires provide evidence against the use of Lithium in the future?
When it comes to small devices, banning Lithium is completely unnecessary, as the risk from small batteries is minimal. Even if such a fire occurs in a high-risk environment (such as an aeroplane), they are rarely able to cause significant damage (of course, they can still cause house fires, but their intensity is far less than those found in e-bikes).
However, in the case of larger systems, such as those found in electric vehicles, a strong argument can be made regarding their safety. While traffic collisions between any vehicles carry the risk of fires (as both fuel and batteries are flammable), stationary EVs left in garages and/or charge stations carry a fire risk simply not found in traditional vehicles. As such, rules could be introduced that require both alarms and suppression systems fitted into spaces where EVs are expected to be left unattended.
Another area that needs to be addressed with regard to safety is smaller EVs, such as e-bikes and scooters. As these devices see almost no regulation, it is easy for low-quality products to make their way into the design.
Furthermore, it is believed that a number of e-bike and e-scooter fires have resulted from using generic chargers as opposed to an official charger. By using such chargers, it is possible for critical safety systems found in the official charger to go unused, resulting in overcharging, undercharging, or overvoltage incidences.
So, what can engineers do to better protect users from the dangers of Lithium? One option is for larger batteries to have in-built charging circuits and accept standardised power sources (such as the mains voltage). By doing so, users will be able to eliminate the need for generic external chargers, thereby increasing the overall safety of the system. However, with regards to lithium fires in the first place, besides using incredibly thick shielding to protect against damage, there is little that can be done. The only hope for engineers on this front is that solid-state batteries become a reality, and while such batteries would still generate massive amounts of heat, they would not release vast quantities of hydrogen gas when they fail.
While the dangers of lithium batteries are real, it's essential to approach such incidents with a balanced perspective. Relying on confirmed information, understanding the broader context, and avoiding premature conclusions will ensure a more informed and accurate understanding of such events.