Comment by mrtksn

> The most likely is either some explosive besides the battery, or something that looks like a battery from the outside, but is actually half explosive

That is the most plausible explanation. It can’t be an obvious thing or someone would notice it. If it looks like a plain battery pack, nobody would think of cutting it open.

One easy way to conceal the explosive would be to overmold it in a cavity inside the plastic enclosure. This would escape all but the most thorough inspections. And since battery terminals are typically also embedded in the plastic this can provide a clandestine supply of power and signal with something like Dallas protocol to the fuse.

I work in the battery space.

All you have to do is build replacement batteries without the pressure relief vents. You can easily get a Chinese manufacture to do this for a fee and properly some complaining about how stupid it is to do.

Then wrap it in some nichrome wire and have a micro run some power through it. The nichrome wire will overheat the cell really quickly causing the cell to rapidly over pressurize and boom.

Small pouch or prismatic cells that would be used at the size of a pager generally won't burn. And I speak from experience of doing stupid shit to them in the name of testing, nothing like using the nail puller side of a hammer to puncture them, or rigging up a fixture with 3 concrete nail guns to shoot it or well, fun stuff

You are probably right but explosives risk detection, either by the militants or by the airport security if taken to a flight to a country with serious security.

I don’t think they’re saying you’d need to change the chemistry though, they’re saying they could have altered way it was packaged so that when it started burning there was nowhere for the gas to go.

Similar to how firecrackers work. If you take a firecracker apart and light the powder, you’ll get a flash and a lot of smoke, but no bang. The explosion comes from the pressure building up in an enclosure.

Disclaimer: not a chemist. Just a former unwisely curious kid

Yeah, this should remove any doubt that there were explosives involved. At the 500 to 1000 mA hour capacity typically used in pagers, even tampering with the battery's venting in an attempt to build up gas pressure would at worst result in a pop and some smoke from the top of the bag.

Blowing a hole in the side of the bag and sending debris for several meters is obviously not plausible with that quantity of lithium.

The explosion in the video does show visible smoke, but there is not a visible flame or fire.

[flagged]

whoever is good/evil aside...

hezbollah got totally owned and look like fools...relying on tech they just took at face value out of the box

Urg, I used exactly this brand in the past.

Is an interesting problem. Maybe the experts in the area could help here. I assume that a worn battery near the end of its life is more prone to explode, but I wonder...

Would the dead cells in the battery take part in that; or are just dead and not reactive.

In other words: if a battery has only a 30% remaining alive; or a laptop has a very worn battery, would an hypothetical explosion by overheating be much less severe? or is still so dangerous as new?.

Those are NiMHs, aren't they? WTF? That shouldn't be possible.

Any idea what prompted the explosion?

According to this post, the pagers that exploded had rechargeable batteries. They even used USB-C, so Hezbollah must be using somewhat fancy pagers: https://x.com/BabakTaghvaee1/status/1836082246538629490

So that Israel couldn't track their locations via cell networks. Sure you could use Signal or w/e but it's the cell IDs and knowing where people are that was the issue. The pagers do far less, if any, two way communication so it's not likely to give away location data.

Pagers don't have GPS devices embedded in them.

Apps (some more or less than others) represent a target for a nation state to pursue for information, graph analysis, bugging, etc.

Because cellphones transmit, pagers don't.

No, a pager is optimized to be a case size that's comfortable for carrying and reading. The electronics could be the size of the smallest wristwatch, which is already dominated by its own form factor requirements, not the PCB + battery + display subcomponents that are scarcely the size of a nickel.

A typical pager is about 60 x 40 x 20mm. Much of this volume requirement is driven by the 16mm diameter 34mm long CR123 battery, a lot of it could be empty.

That battery is a relatively safe lithium primary chemistry, not a rechargeable Lithium polymer pounch or lithium ion cylinder that would risk fire and explode if the overpressure vents were omitted and the BMS corrupted, but the primary lasts for years.

I bet you could use a CR1216 battery (1.6mm thin, 30mAh, instead if 34mm long and 1500mAh) instead and have quite a good deal of spare volume in the battery for an explosive. If you filled the entire pager, that would be even more room, but much more easily detected.

Because it takes a surprisingly small amount of high explosive to cause the kind of damage shown in the footage we’ve seen so far. All it would take is for the battery to be replaced with a combo package - part battery, part explosive. No need for additional internal space.

Disclosure: my first job was in the Australian Defence Science Technology Organisation, Materials Research Lab, Explosives Instrumentation Group.

I think it makes more sense to think of these as explosive devices manufactured by/for Israel that are just designed to pass as pagers.

If cost per unit isn’t a consideration, I suspect you can shrink the size of the electronic components used in the pager to make room for a 20 gram explosive charge.

Pagers—especially commodity models—aren’t profitable enough to warrant cutting edge tech with the latest advances in microelectronics. Lots of room to improve things if you are making a set of them at a loss.

One possibility is to replace part of the battery. The smaller battery can be designed to lie about its charge, or you can replace with a higher energy-density battery and use the space saved for a detonation system (perhaps even incorporating the battery itself into this) and a small quantity of high explosive, which is pretty stable and safe until detonated. Contrary to popular belief, high explosives are actually relatively safe, and usually even burn safely or are hard to ignite at all in some cases. Package it up into something that looks identical to an unmodified battery. Modify device firmware and battery control circuitry to detonate it on receipt of a specific signal and... boom.

Thinner (less durable, but who cares?) plastic shell to free up space for explosives, but would likely be obvious if someone opened it - which might be a common thing if these were being used as remote triggering devices.

If they were using a AA battery, replace the battery with something that provides you space to work (e.g. put in a AAAA or button cell that would provide appropriate power but lower capacity) because you don't really care if the battery life drops from months to weeks.

Pagers, by definition, are likely to be older technology.

The internals could be replaced with modern smaller and lower-power equivalents, requiring a smaller battery, and saving enough space.

(Or maybe somebody just donated a batch of innocent-looking devices to 'the cause', or offered a bargain on some 'extra secure' pagers?)