As global electric vehicle adoption skyrockets, automotive supply chains face the unprecedented challenge of shipping millions of lithium-ion batteries safely as these items represent one of the most volatile cargo risks in modern logistics history. Last year, a cargo ship that had been delivering new vehicles to Mexico caught fire in the North Pacific Ocean. According to CNN, the Morning Midas, which departed the Chinese ports of Yantai in May 2025, was loaded with 3,000 new vehicles, including 70 fully electric and about 680 hybrid models. Since fires involving EVs are harder to extinguish, the crew members onboard had no choice but to evacuate to a lifeboat, and the fire is said to have burned for more than a week.
The shipping industry has arrived at a critical crossroads as shipping powerful and chemically reactive batteries requires rewriting the maritime safety playbook. To mitigate these catastrophic risks, manufacturers and logistics providers are focusing on the battery’s State of Charge (SoC), which refers to the amount of energy stored in a battery relative to its total capacity. To ship vehicles safely, here’s how EV manufacturers and automotive logistics balance battery charge and transport risk.
Balancing Efficiency and Safety
Thermal runaway is the most dangerous hazard for an electric vehicle battery. This phenomenon occurs when an internal short circuit triggers an uncontrollable, self-sustaining spike in temperature. Ultimately, the energy stored within the cell directly determines the severity of the resulting fire or explosion, and it’s why most new EVs ship completely uncharged. This results in a safer transport, but as EVs have to be driven onto open trailers, enclosed containers, or Roll-on/Roll-off ocean vessels, it creates a major logistics challenge. So how do you safely move an electrical vehicle that has no electrical power to move itself?
Shipping a battery completely dead may be the safest option, but it has its limitations. To address shipping challenges, international regulators and industry leaders have established strict limits on transport energy levels. The International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) mandate a maximum State of Charge of 30 percent for lithium-ion batteries shipped as cargo. At 20 to 30 percent SoC, the battery contains enough energy to allow logistics drivers to drive the vehicle short distances, such as up a RoRo ramp, but it will lack the volatile energy density required to sustain a catastrophic thermal runaway chain reaction.
Deep Discharge vs. Battery Health
For EV manufacturers, releasing their vehicles for transport at zero percent SoC is completely unfeasible due to the chemistry of the batteries. If a battery drops into a state of deep discharge during a long ocean transit, this may cause the copper to drop into the electrolyte and create dendrytes, which are microscopic, needle-like metallic lithium crystals that grows on the anode during charging and recharging. These dendrites can cause internal short circuits, increasing the risk of a fire hazard after the vehicle is delivered to the dealership or consumer. Meanwhile, shipping a vehicle with a 50 to 100 percent SoC not only results in heightened risks of intense, inextinguishable fires, but it also accelerates battery degradation.
To successfully walk the fine line between battery safety and chemistry protection, automotive supply chains have started using a new strategy to protect shipping crews, consumers, and their vehicles. EV assembly plants now use end-of-line software calibrations to systematically discharge or charge battery packs to exactly 25 to 30 percent SoC prior to tracking and loading onto RoRo vehicles. Major brands such as Tesla and BYD have already adjusted their factory exit or port staging charging protocols to comply with carrier and maritime limits rather than shipping vehicles at 100 percent full capacity.
Preventing EV Battery Fires at Sea
To keep crews and cargo safe, forward-thinking logistics providers are embedding temporary smart sensors into vehicle fleets. These sensors track temperature spikes inside cargo holds, alerting the ship’s crew to a potential thermal event hours before visible smoke or flames appear. Shipping lines are also retro-fitting vessels with fire blankets that are specially designed to smother EV fires, in addition to high pressure water lances that can penetrate battery casings from a safe distance to cool the cells.
Another technique that ships use is cargo segregation. Instead of clustering EVs tightly together, the vehicles are isolated or spaced out on specific vehicle decks. Doing so limits the rapid spread of fire if a single battery experiences thermal runaway.
The logistics of EV shipping requires an ongoing, delicate balance of maximizing State of Charge efficiency and minimizing transport risk. As technologies evolve, the automotive supply chain should continue to innovate to ensure safety and efficiency while meeting electric vehicle demand in different parts of the world.
About the author
Carina Black is a writer who loves to transform intricate concepts into engaging narratives. She is always eager to expand her audience and share her insights across diverse platforms. When she’s not writing, she enjoys discovering quaint cafes and spending quality time with her loved ones.
