In conjunction with the International Group of P&I Clubs, TT Club and ICHCA, Cargo Incident Notification System (CINS) published a report on transporting batteries inside containers titled “Lithium-Ion Batteries in Containers Guidelines”, reports Safety4sea.
Parts and Operation of a Lithium‐Ion Battery
Lithium‐Ion Batteries have the highest charge density of any comparable system. This means they can provide a lot of energy relative to their weight. A lithium‐ion battery is made up of several individual cells that are connected to one another. Each cell contains three main parts: a positive electrode (a cathode), a negative electrode (an anode) and an electrolyte.
If the separator is damaged, the electrodes can touch each other, causing electrical short circuit and significant Joule heating which triggers thermal runaway. The heat in a single cell is rapidly transferred from cell to cell in a cascading effect called thermal propagation. Eventually, the gases are vented from the cell, taking with them droplets of the organic solvent producing a white vapour cloud.
If this ignites immediately, long flare‐like flames are produced. If ignition is delayed, a vapour cloud explosion can occur, and indeed such VCEs have occurred involving Lithium‐ion Batteries in E‐scooters as well as grid‐scale Battery Energy Storage Systems (BESS).
Lithium-ion battery cargo issues
Under certain conditions there may be an increase in the internal temperature of a lithium‐ ion cell, which in turn can initiate exothermic reactions (these are reactions which release heat). This can create a heat‐temperature loop, leading to higher internal temperatures and further exothermic reactions.
If this heat does not dissipate, the battery cell temperature will elevate further, thereby accelerating the process of heat release. The battery enters an uncontrollable, self‐heating state.
This process is called thermal runaway. Thermal runaway will affect neighbouring cells in the battery and adjacent batteries, as well as other substances and commodities in the vicinity. These exothermic reactions can give off oxygen enabling combustion.
Lithium‐Ion Battery Hazards
The consequences of a Lithium‐Ion Battery fire can be severe. Typical fire risks, whether on board ship or ashore, are:
- Thermal runaway events and conditions
- Fire suppression
The effects of thermal runaway may start a fire which is difficult to extinguish. Normal fire extinguishing tools and materials may not be efficient and/or sufficient.
- Fire propagation and heat flux
Another effect is related to the related reactivity characteristics and the heat flux of the materials in the vicinity of the fire. Especially when other Lithium‐Ion Batteries are in the direct vicinity. This is known as “fire propagation”.
- Fire and explosion
The reaction and fire may evolve into an explosion, depending on the circumstances.
Thermal runaway reaction products contain many toxic substances, and prevention and protection is necessary. The substances are very toxic, highly toxic, and toxic which are the three most dangerous levels of poison classified under China National Standards.
These toxicity characteristics are applicable not only to the gas cloud and to the residue that remains after the fire. The thermal gas reactions generated different type of toxicity risks that were directly related to the state of charge of the Lithium‐Ion Battery with a battery at 100% state of charge being the most dangerous in terms of toxicity and hazards.
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