The Australian Maritime Safety Authority (AMSA) has published an outline of safety lessons learned from an incident wherein a domestic commercial vessel suffered an onboard fire caused by a thermal runaway event involving a lithium-ion battery system.
An explosion occurred on a charter fishing vessel whilst berthed. The investigation identified that the ignition source was a lithium-ion battery that was not holding charge connected to a battery charger in a way that bypassed the battery management safety system.
The vessel was beyond repair following the explosion.
At 23:30 on the date of the incident, a berthed charter fishing vessel experienced an explosion. The force of the explosion scattered debris up to 30 metres and ejected a 200kg deck winch and a section of deck, which came to rest at the vessel's stern.
AMSA said that, while there was evidence of smoke and fire, the destruction was caused by the explosion itself.
The vessel owner reported previously having issues with the lithium-based battery system attached to the pot winch on board. They had purchased a new charger and installation services from an auto electrician on the afternoon of the incident.
The electrician was working on the vessel and fitting the new charger temporarily to the system to be left to charge overnight. The electrician stated they left the vessel at approximately 19:30 and set the charger shortly before departure.
The explosion happened at night and while the vessel was berthed. Fortunately, no one was on board at the time and no injuries were sustained.
However, the vessel itself was considered beyond repair.
AMSA said that, although the extent of the damage made conclusions from the explosion problematic, it appears the installation of the new battery charging system potentially bypassed the battery management system.
It was also noted that the location of the lithium-ion battery installation was not ventilated as required by the Australian Standards.
Vessel owners/operators should develop and implement a procedure for onboard charging of electronic devices and battery systems. This should consider the risk of a thermal runaway, including venting of toxic and flammable gases and compounds.
When a lithium-ion battery enters thermal runaway, there is an intense release of heat and toxic gases, some of which are also explosive. These types of thermal runaway events can also lead to fires that are extremely difficult to extinguish.
Lithium-ion batteries are required to be installed in accordance with the National Standard for Commercial Vessels Sub-section C5B Electrical.
AMSA added that it is essential that lithium-ion battery installations include an approved battery management system to avoid potential overcharging events. Ventilation air flows must also be in accordance with manufacturer's specification.
