Read this: US testing of lithium batteries alarms aviation officials http://news.yahoo.com/us-testing-lithium-batteries-alarms-aviation-officials-200358046—finance.html
International aviation officials are trying to quickly come up with safer packaging for cargo shipments of lithium-ion batteries on passenger planes after U.S. testing confirmed that aircraft fire suppression systems can’t prevent overheated batteries from causing powerful explosions and fires.
“The attraction of a lithium-ion battery is that lithium is the least dense metallic element, which means that weight-for-weight it can pack more power than other types of battery. But lithium is also a highly reactive substance; it belongs to the alkali metal group, which contains sodium and potassium, the high reactivity of which will be familiar from school chemistry classes.
“Like all batteries, lithium ones consist of two electrodes separated by an electrolyte. Typically for a lithium cell the electrolyte is a solution of lithium salts and organic solvents. When the battery is charged, lithium ions are driven from the electrolyte into a carbon anode. When the battery is discharged they flow back, creating a balancing flow of electrons in a circuit that powers the device.
“The trouble comes about if there is a small fault or damage is caused to the extremely thin separators that keep the elements of the battery apart. This can lead to an internal short-circuit and a subsequent build-up of heat. This can trigger what is known as a “thermal runaway” in which the battery overheats and can burst into flame. That can cause adjacent battery cells to overheat, which is why groups of cells in some battery packs (such as those used in Tesla cars) are kept in separate protective compartments.
“Lithium batteries can also be damaged by using them in hot environments, and by excessive discharging and charging—which is why most lithium batteries contain special circuits to prevent this. Catching fire if something goes wrong, then, is in their nature.”
http://www.economist.com/blogs/economist-explains/2014/01/economist-explains-19
The solution is relatively simple. They should use Lithium Iron (LiFePO4) batteries. They are much more stable, less prone to thermal runaway. They do weigh a little more than LiIon or LiPO batteries but are still lighter than NiCd, Nimh, or Lead acid batteries.
'Safer packaging' isn't going to help much, because something that will actually contain a lithium fire is going to add so much to the bulk and weight of the package so as to eliminate the weight and size advantages that LiIon and LiPO give.