Lithium batteries are restricted or banned in specific contexts — particularly on aircraft and in checked luggage — because damaged or defective cells can enter thermal runaway, generating intense heat that's extremely difficult to extinguish mid-flight.
The core risk isn't LiFePO4 chemistry specifically; it's lithium-ion and lithium-polymer cells, which use cobalt-based cathodes that are far less thermally stable. Regulatory bodies like the FAA and IATA limit lithium battery transport based on watt-hour capacity and cell type because the energy density that makes lithium batteries useful also makes uncontrolled failure catastrophic in an enclosed space. LiFePO4 chemistry, with its iron-phosphate bond, is significantly more stable — but it still falls under broad lithium transport rules in many jurisdictions.
- FAA regulations ban lithium batteries over 100Wh from carry-on without airline approval; over 160Wh is generally prohibited entirely.
- Lithium-ion thermal runaway can reach temperatures exceeding 1,000°F — conventional aircraft fire suppression systems cannot extinguish it.
- LiFePO4 batteries are thermally stable up to roughly 518°F before breakdown, versus approximately 302°F for cobalt-based lithium-ion cells.
- IATA dangerous goods regulations classify lithium batteries as Class 9 hazardous material for shipping purposes.
- A 12.8V 100Ah LiFePO4 pack holds 1,280Wh — well above the threshold that triggers airline and freight carrier restrictions.