First, it was 3000 kilometers, not miles. Second, the energy source is the oxidization of Aluminum. It takes specific preparation (e.g. thermite) to release t

First, it was 3000 kilometers, not miles. Second, the energy source is the oxidization of Aluminum. It takes specific preparation (e.g. thermite) to release that all at once. The contents of this "battery" are as safe as carrying around a bunch of crumpled up beer cans (very safe) and whatever the heck that solvent is (unknown). The solvent may be toxic, acidic, etc. but hopefully no worse than what's in your car battery, which is actually pretty nasty but not terribly dangerous unless you deliberately try to make it so (e.g. by shorting out the terminals). Aluminum is currently under $2K/1000kg, so the yearly aluminum battery replacement would probably run a few hundred dollars. Aluminum is the most abundant metal on earth and this reaction is reversible, so costs should stay low. The real cost is likely to be the solvent.