Preparing for the fire in lithium-ion batteries

As superyachts continue to embrace diesel-electric hybrid propulsion and advanced energy management systems, lithium-ion (Li-ion) batteries have become a cornerstone of modern yacht design. Increased demands for silent operation, reduced emissions, and greater energy efficiency have all driven the adoption of large-scale battery storage solutions across the industry.

With these benefits, however, comes a growing responsibility to understand and manage the unique risks associated with Li-ion technology.

Today's hybrid superyachts rely heavily on battery banks to support hotel loads, propulsion systems, and energy optimisation strategies. Larger battery capacities allow vessels to operate more efficiently, reduce generator running hours, and enhance guest comfort through quieter operation.

Beyond propulsion systems, Li-ion batteries are now found throughout the vessel. From tenders, e-bikes, and water sports equipment to guest electronics, mobile phones, tablets, laptops, power tools, and handheld UHF radios, battery-powered devices are part of everyday life onboard. As battery use increases, so does the potential exposure to battery-related incidents.

Unlike conventional fires, a Li-ion battery fire presents unique challenges. The primary hazard is a phenomenon known as thermal runaway: an uncontrollable chain reaction within the battery cell that generates extreme heat and can rapidly spread to adjacent cells.

Thermal runaway can be triggered by overcharging or charging system failures, physical damage or impact, manufacturing defects, internal short circuits, excessive heat exposure, saltwater ingress, and corrosion.

During thermal runaway, battery temperatures can exceed 700°C, releasing flammable gases and highly toxic combustion products. Alarmingly, these gases may be released before visible flames appear, creating a significant risk to personnel responding to the incident.

Adding to the challenge, Li-ion battery fires can reignite hours or even days after appearing to be extinguished, requiring prolonged monitoring and careful management.

Research and incident investigations continue to demonstrate that Li-ion battery fires do not always respond to traditional firefighting methods. While conventional firefighting strategies typically focus on removing heat, fuel, or oxygen, Li-ion batteries can continue to generate heat internally, making suppression significantly more complex.

For larger installations, dedicated battery rooms are increasingly being incorporated into yacht designs. These areas must have specific detection and be appropriately monitored. Alternative battery technologies, such as sodium-metal chloride (SMC) batteries, are beginning to emerge within the maritime sector. While generally offering lower energy density than Li-ion batteries, they provide certain safety advantages, including the absence of thermal runaway risk. However, Li-ion technology remains the preferred choice for most hybrid yacht applications due to its superior energy storage capability and efficiency.

When discussing battery safety onboard, attention is often directed towards large battery banks or high-profile equipment such as electric tenders and water toys. However, some of the most significant risks can come from much smaller devices.

Industry incidents have demonstrated how seemingly routine equipment, such as portable UHF radios, can cause serious damage when charging faults or battery failures occur. In one reported case, an unattended radio entered thermal runaway and caused extensive damage to a vessel's bridge before the fire was brought under control.

A damaged phone charging on a cabin bunk, an overheated laptop left unattended, or a faulty handheld radio connected to a charger can all become ignition sources in vulnerable onboard environments.

As Li-ion technology becomes increasingly embedded within modern yachting operations, effective risk management must become a routine part of onboard safety culture.

Captains and crew should maintain an inventory of Li-ion-powered equipment carried onboard, including personal devices belonging to crew and guests. Comprehensive risk assessments should identify potential hazards associated with charging, storage, transportation, and use.

Emergency drills should specifically address Li-ion battery scenarios. Realistic and focused exercises help ensure crew understand the unique behavior of battery fires and can respond confidently in an emergency.

George Self is Safety & Compliance Manager at Riela Yachts, part of the Riela Group. The Group provides specialist superyacht, technical, corporate, technology and cyber security services to Owners and their teams worldwide.