How to prevent short circuits during lithium-ion transport?

Safe transport of lithium-ion batteries is crucial for both defense and commercial applications. Short circuits during transport can lead to overheating, fire, and even explosions. To prevent this, specific measures are necessary, including proper packaging materials, insulation between battery terminals, protection against external damage, and compliance with international transport regulations. These measures help to control the risks and ensure safe transport of these powerful but potentially dangerous energy sources.

What are the risks of short circuits in lithium-ion batteries?

Short circuits in lithium-ion batteries can lead to a thermal chain reaction where the temperature rapidly rises to more than 500°C. This phenomenon, known as ‘thermal runaway’, causes fire and potentially explosions because the electrolyte in the battery is flammable and can ignite under pressure.

Short circuits occur when the positive and negative terminals of a battery come into direct or indirect contact with each other. In lithium-ion batteries, this is especially dangerous due to the high energy density and chemical composition. Unlike traditional batteries, lithium-ion cells can form lithium metal particles when damaged, which act as a kind of internal bridge and cause short circuits.

The consequences can be far-reaching:

• Overheating and fire hazard of the battery itself
• Release of toxic gases and vapors
• Spread of fire to surrounding materials
• Chain reaction when multiple batteries are in proximity to each other
• Explosion hazard due to pressure buildup in closed battery housings

What makes lithium-ion batteries particularly dangerous during transport is that damage is not always immediately visible. A battery can be internally damaged by shocks or vibrations during transport, after which it can take hours or even days before an actual short circuit and fire occurs.

What legal requirements apply to lithium-ion transport?

The transport of lithium-ion batteries is strictly regulated due to the inherent risks. International regulations are established in the UN recommendations for the transport of dangerous goods, with classification UN3480 (for lithium-ion batteries) and UN3481 (for batteries packed with or contained in equipment).

For road transport within Europe, ADR regulations apply (Accord européen relatif au transport international des marchandises Dangereuses par Route). These stipulate that:

• Batteries must be tested according to the UN Manual of Tests and Criteria, Part III, subsection 38.3
• Each shipment must have proper documentation and hazard markings
• Packaging must comply with specific UN packaging instructions (PI965 to PI967)
• Restrictions apply to the number of watt-hours (Wh) per battery and per package

For air transport, the IATA guidelines (Dangerous Goods Regulations) are even stricter. Since 2016, loose lithium-ion batteries (UN3480) can no longer be transported as passenger cargo, and strict load limits and packaging requirements apply for cargo aircraft.

As a shipper, you are fully responsible for correct classification, packaging, marking, labeling, and documentation. Non-compliance can lead to substantial fines, liability in case of incidents, and refusal of transport.

How do you protect lithium-ion batteries against external damage?

External protection of lithium-ion batteries begins with robust packaging materials that can absorb shocks and vibrations. This physical protection is the first line of defense against short circuits caused by external damage.

Effective protection methods include:

• Shock-absorbing materials such as special foam with different densities that is precisely cut to size for the battery or device
• Reinforced containers made of high-quality materials such as aluminum or impact-resistant plastic that can withstand extreme conditions
• Custom-fit packaging solutions where the battery or device is packaged to fit exactly to minimize movement during transport
• Protection against point loading through pressure-distributing materials that prevent sharp objects from piercing the battery

For military applications or transport in extreme conditions, there are specialized defense packaging solutions that meet MIL-STAN specifications. These offer extra protection against factors such as extreme temperatures, moisture, dust, and chemical influences.

In addition to the packaging itself, it’s important to protect batteries with individual casings or protective covers that shield the connection points. This prevents metal objects such as keys or coins from making direct contact with the terminals.

Why is electrical insulation crucial in battery packaging?

Electrical insulation is the most direct way to prevent short circuits. It involves creating a non-conductive barrier between the battery terminals and between different batteries. Without proper insulation, even small vibrations or shifts during transport can lead to unwanted contact and short circuits.

Effective insulation methods are:

• Individual cell packaging where each battery cell is separately packaged in non-conductive material such as plastic bags or special battery holders
• Terminal covering with insulating caps, tape, or protective covers that completely cover the positive and negative connection points
• Non-conductive dividers between batteries when multiple cells are transported together
• Insulating trays or inserts with custom-made recesses for each battery
• Anti-static materials that prevent static electricity from causing short circuits

When designing insulation, it’s important to consider the specific battery type and configuration. Cylindrical cells (such as 18650 batteries) have different insulation requirements than prismatic cells or battery packs.

Also note that the insulation materials themselves must be resistant to environmental conditions during transport. Some insulation materials can weaken at extreme temperatures or after prolonged exposure to vibrations.

When should you use specialized transport containers?

Standard packaging is not always sufficient for safely transporting lithium-ion batteries. There are specific circumstances where specialized transport containers become necessary:

• High energy density: Batteries with a capacity of more than 100Wh often require special UN-certified packaging
• Large volumes: When transporting multiple batteries at once, a container with compartmentalization is needed to prevent the spread of fire
• Long transport distances: Intercontinental transport or transport via multiple modes (road, sea, air) requires more robust protection
• Extreme climate conditions: Transport through areas with extreme heat, cold, or humidity requires thermally insulated containers
• Damaged batteries: For the transport of defective or damaged batteries, extra strict requirements apply, including special fire-resistant containers

Specialized containers offer advantages such as:

• Built-in fire-resistant properties that can contain a fire
• Pressure relief to minimize explosion hazards
• Temperature regulation to prevent overheating
• Monitoring of battery status during transport
• Certified compliance with international safety standards

For defense and security applications, where batteries often need to be transported under challenging conditions, containers with extra robust features and military certifications are available.

Conclusion

Safely transporting lithium-ion batteries requires a combination of proper packaging materials, electrical insulation, protection against external factors, and regulatory compliance. By carefully addressing these aspects, you minimize the risk of short circuits and their dangerous consequences.

Remember that the responsibility for safe transport lies with the shipper. Investing in the right packaging solutions is not only a legal obligation but also an investment in the safety of people and goods.

At Faes, we understand the complexity of safely transporting sensitive and potentially dangerous components such as lithium-ion batteries. We develop packaging solutions that not only comply with all regulations but are also practical and user-friendly for your specific application.