Unresolved airplane crashes that were likely caused by batteries catching fire onboard during flight include the Asiana Airlines 747 near South Korea in July 2011, a UPS 747 in Dubai, UAE in September 2010 and a UPS DC­8 in Philadelphia, PA in February 2006. These events prompted changes to the UN Manual of Tests and Criteria in how batteries are certified for transport under UN 38.3.

Safety prompted authorities to tighten the rules when transporting batteries. Although lithium batteries get the most attention, the Federal Aviation Administration (FAA) says that based on records from 1991 to 2007 it was only a factor in 27 percent of all incidents. Lead acid, NiMH, NiCd and alkaline are also to blame. Reports say that short circuit, a preventable problem that can be solved with better packaging, is the largest problem

Lead Acid

Spillable lead acid batteries are regulated as dangerous goods under Class 8, controlled by UN 2794. These batteries are considered dangerous goods because of the possibility of fire if shorted. Furthermore, an acid spill can cause personal injury and property damage.

When transporting Class 8 goods, note that a vehicle can only carry one type of hazardous material. Stack batteries upright on a wooden pallet, place honeycomb cardboard between layers and limit stacking to three layers per pallet. Wrap the pallet with shrink­wrap to improve stability. Add the “Corrosive” label, UN 2794 identification number and mark: “Wet, filled with acid.” Provide bill of lading with description of hazardous material, company and shipper’s name. Following picture shows do’s and don’ts.

Some wet, non­spillable sealed lead­acid batteries grouped under UN 2800 are exempt from Class 8. The battery manufacturer must declare how a battery is regulated on its associated Material Safety Data Sheet (MSDS) and most AGM (absorbent glass mat) batteries can be shipped under the simpler UN 2800 directive. MSDS contains information on the potential health effects of exposure to chemicals or dangerous substances and on safe workplace procedures when handling chemical products.

Different rules apply when shipping damaged batteries. A lead acid battery is considered damaged if the possibility of leakage exists due to a crack or if one or more caps are missing. Transportation companies and air carriers may require draining the batteries of all acid prior to transport. Place damaged batteries in an acid­resistant container and add soda ash to neutralize any acid that might spill. Separate damaged and intact batteries.

Nickel­based Batteries

Nickel­based batteries have no transport limitations; however, some of the same precautions apply as for lead acid in terms of packaging to prevent electrical shorts and safeguard against fire. Regulations prohibit storing and transporting smaller battery packs in a metal box. If there is a danger of an electrical short, wrap each battery individually in a plastic bag. Do not mix batteries with coins and house keys in your pocket.

Lithium­based Batteries

The largest changes in shipping directive are with lithium batteries, and with good reasons. Li­ion is the fastest growing battery chemistry and already in 2009, 3.3 billion Li­ion were transported by air. Safety is an ongoing concern, and an airline­pilot association asked the FAA to ban lithium batteries on passenger aircraft. This came into effect in 2016 and lithium batteries are now shipped in cargo airplanes only.

Lithium batteries can only be transported after passing UN 38.3 testing requirements. In spite of these precautions, the U.S. Federal Aviation Administration (FAA) recorded 138 airport and air incidents between 1991 and 2016 involving lithium batteries. They involved smoke, heat and fire related to battery­operated devices such as e­cigarettes, laptops and mobile phones. Some incidents occurred before takeoff and the batteries were removed from the aircraft. Battery fires in flight were extinguished with halon type fire extinguishers and water, by placing the damaged device in a thermal battery containment bag that some airlines carry. Failing batteries in the cargo hold that were inadvertently checked into luggage required emergency landings.

Not all incidents are reported to the FAA, but the number of reported incidents is up from 2015. Recorded failures in 2016 alone involved 13 e­cigarettes, four laptops, seven mobile phones/tablets and seven spare batteries. E­cigarette incidents increased notably, while mobile phone and laptop events remain moderate considering the number of such devices in use.

Since 2008, lithium batteries can no longer be placed in checked baggage; they must be carried onboard. Air travelers are reminded of how many batteries they can carry with a portable device and as spares. Quick access to a fire extinguisher enables putting out a fire in the cabin should one take off. A coffee pot served as the fire extinguishing device for a flaming laptop battery in one reported incident. This is not possible with a burning battery in the cargo hold.

Transported lithium­based batteries are divided into two types: The rechargeable lithium­ion is primarily found in mobile phones and laptops; the non­rechargeable lithium­metal with added restrictions because of its high lithium content is used in sensing devices as well as in some consumer grade AA, AAA and 9V formats. Airlines allow both types as carry­on, either installed in devices or carried as spare packs as long as they don’t exceed the following limitation of lithium or equivalent content:

• 2 grams per battery for non­rechargeable lithium batteries, also known as lithium­metal.
• 8 grams per battery for a rechargeable lithium­ion. This amounts to a 100Wh battery.
• 25 grams total per passenger for all Li­ion combined, amounting to 300Wh.

The lithium content of a lithium­metal battery is printed on the label. Li­ion, on the other hand, uses equivalent lithium content (ELC) that is calculated by multiplying the rated capacity (Ah) times 0.3. For example, a 1Ah cell has 0.3 grams of lithium. A modern 18650 cell with a capacity of 3.3Ah contains about 1 gram. The 8­gram limit permits a 26Ah battery, or 95Wh (Ah multiplied by the Li­ion cell voltage of 3.6V equals Wh). The 18650 is a standardized Li­ion cell of 18mm in diameter and 65mm in length, and is used in laptops, power tools and other devices. Most laptop batteries are in the 60Wh range.

While regulations limit the Li­ion battery to no larger than 100Wh, each passenger is allowed to carry two spare packs of 160Wh each, not exceeding 320Wh in total. The airlines recommend placing each battery in a clear plastic bag to prevent electric short. Batteries that are contained (non­removable) within a device and are not easily removable are exempt from the rules. These include electric watches, smartphones and laptops but not power tools with interchangeable battery packs

All lithium batteries are considered to be dangerous goods and transporting them requires compliance with Class 9 directives. However, exemptions are made when shipping these batteries in small quantities. Personnel transporting lithium batteries commercially must be trained. Organizations such as iHazmat or the International Compliance Center (ICC) educates shippers and packers in the handling of dangerous goods consistent with to International Air Transport Association (IATA) requirements and issues a certificate of compliance to those participants who pass a written examination. Those not familiar with these restrictions often ask some of the following questions:

Q:	Must consumer­type lithium­ion batteries always be shipped under Class 9

A:	No. Most Li­ion in consumer products are less than 100Wh and an exemption is made here but CAUTION labeling is required.

Q:	What quantities can I ship outside of Class 9
A:	Cells with a maximum rating of 20Wh and not exceeding 8 in quantity, or 2 batteries with a maximum rating of 100Wh each as part of Section II.

Q:	When does Class 9 apply
A:	Lithium­based batteries classified under Section IA and IB.

Q:	Must lithium­ion batteries be tested for shipment
A:	Yes, all Li­ion must be tested according to UN 38.3. Exceptions are made for prototypes and testing purposes. Refer to CFR 49 173.185 (e) for requirements regarding the shipment of cells or batteries that have not been tested to the requirements to UN 38.

Since 2016, lithium batteries can no longer be carried in passenger aircraft as cargo. Transporting them are organized by Packaging Instructions (PI) numbers. The most common designations include:

PI 965	Loose Li­ion cells and packs (UN 3480)
PI 966 & 967	Li­ion with/in equipment (UN 3481)
PI 968	Lithium­metal cells and battery packs (UN 3090)
PI 969 & 970	Lithium­metal with/in equipment (UN 3091)

Each PI is further divided into Sections representing IA, IB and II (Roman numerals). IA is most stringent, and for simplicity this article lists the less restricted packaging first:

Carry­on	Maximum 100Wh, passenger can take 2 spares up to 160Wh each, not exceeding 320Wh. No check­in allowed.
Section II	Shipment of small Li­ion in low numbers. These can include up to 8 cells not exceeding 20Wh each and up to 2 packs not exceeding 100Wh each at a total weight of 2.5kg. Batteries must be at 30 percent state­of­charge (SoC) for shipment. Persons preparing such shipment is exempt from dangerous goods training, but must be provided with “adequate instruction.”
Section IB	Shipment of small Li­ion in low numbers. These can include up to 8 cells not exceeding 20Wh each and up to 2 packs not exceeding 100Wh each at a total weight of 2.5kg. Batteries must be at 30 percent state­of­charge (SoC) for shipment. Persons preparing such shipment is exempt from dangerous goods training, but must be provided with “adequate instruction.”
Section IA	Larger Li­ion products under Class 9 dangerous goods. Cells can be larger than 20Wh and battery packs can exceed 100Wh, but the package limit is 35kg. Batteries must at 30 percent SoC. Training and certification is mandatory.