Can a Flashlight Ever "Explode" ?

The board and spring pad that back the head that's screwed into the body resist, not just the lens....
Yup, circuit board is very tough material (glassfiber/epoxy resin) and even a glass lens can be surprisingly strong when the pressure is distributed evenly.

Tbh I'm surprised in this day an age, that flashlights don't come with weak sections, areas that are meant to give way in order to prevent worse. Like on top of electrolytic capacitors. Design features like that should be standard fare for Li-ion powered lights, imho.
 
The title pretty much says it all.

Can a flashlight with whatever/any batteries in it ever explode due to whatever reason? I mean, if something goes wrong, is it

- EVER possible for the flashlight body to be torn apart/torn into pieces by a battery "explosion" inside the body?

- Or will the batteries (whatever their type) just leak?

- Or will the batteries create some chemical reaction inside the body, create some pressure and when you open the flashlight, it's gonna feel like...opening a bottle of champagne, let's say?


I don't know the first thing about batteries and use only rechargeable AAA/AAs, so.... yeah. I'm just curious.
I understand this is an older post, but I haven't come across many discussions about flashlights exploding.

I'm delving into this topic because my flashlight exploded in my hand, resulting in the loss of the tip of my finger and two surgeries on my eye to remove metal fragments.

I've been reading people's replies, and seeing them laughing as if it's a joke. Let me tell you, this is no F@cking joke! It can and does happen. While it may not be common, once was more than enough for me. This wasn't a mere poof or bang; it was a boom, akin to a cannon or bomb going off. Initially, I didn't understand what had occurred—I thought I had been shot. I couldn't see out of my left eye, blood was everywhere, and my hand was covered in blood, missing the tip of my middle finger. It was only when I searched for my flashlight and discovered the body with a tear in the metal, both ends missing, that I realized what had happened. How it occurred, I still don't know, but it did.

I reached out to the flashlight company (J5 Tactical "The Concealed Network"), and they basically told me to go away. I plan to contact Rayovac next, hoping for a different response.

I'm just trying to raise awareness that, indeed, flashlights or the batteries within them can explode.

No, I didn't modify anything.

No, there was no other electricity touching or near it.

Yes, I have proof: the damaged flashlight and battery pieces, along with pictures and hospital bills.

If anyone else has experienced something similar, please reach out to me.
 

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LoneWolf65 thank you for posting. As you say, this is not funny at all. This is why i got rid of my 2 x CR123 flashlights - just in case. Is your eye OK now?
 
First of all I am sorry your light exploded and I hope you make a full recovery. I would suggest you consult your doctor about hydrofluoric acid exposure, its nasty stuff with very few initial symptoms but can cause major damage. I would also suggest you read this thread Roar of the Pelican. So far it is the only thread I have found that seems to have any real explanation as to the cause of cr123 explosions without physical damage to the cells. Basically if one cell is at 60 to 70% charged and the other is around 100% it can cause one cell to go into thermal run away and it can eventually explode.

I'm generously curious about what caused this explosion so could you tell us a little more about what happened? The events prior to the explosion? Is it possible the light got wet? Possibility of hydrogen build up? The specs on the light? The cell that exploded ?As far as I can tell the J5 lights are all single AA/14500 cell formats.
 
LoneWolf65 thank you for posting. As you say, this is not funny at all. This is why i got rid of my 2 x CR123 flashlights - just in case. Is your eye OK now?
Toulouse42, yes my eye is better. I have a small rust stain, it can be ground out.. but I'm leaving it, my battle scar.
 
First of all I am sorry your light exploded and I hope you make a full recovery. I would suggest you consult your doctor about hydrofluoric acid exposure, its nasty stuff with very few initial symptoms but can cause major damage. I would also suggest you read this thread Roar of the Pelican. So far it is the only thread I have found that seems to have any real explanation as to the cause of cr123 explosions without physical damage to the cells. Basically if one cell is at 60 to 70% charged and the other is around 100% it can cause one cell to go into thermal run away and it can eventually explode.

I'm generously curious about what caused this explosion so could you tell us a little more about what happened? The events prior to the explosion? Is it possible the light got wet? Possibility of hydrogen build up? The specs on the light? The cell that exploded ?As far as I can tell the J5 lights are all single AA/14500 cell formats.
Ghostguy6, the power went out and I was using my flashlight to get a few candles going. I had it on for probably 15-20 minutes before the explosion. It was a J5 and it had a single cell AA lithium battery in it. It didn't get wet, I wAs in my house. It never felt warm or gave any signs before it blew, no glasses coming from it, no noise.. just kaboom. I mean it was really loud. It blew pieces all around the place. Three months later while cleaning out my toaster I found a piece of the battery in it..lol. I'd love to figure out what happened. To this day I won't use a flashlight. I hardly even keep my cell phone on me..
 
Ghostguy6, the power went out and I was using my flashlight to get a few candles going. I had it on for probably 15-20 minutes before the explosion. It was a J5 and it had a single cell AA lithium battery in it. It didn't get wet, I wAs in my house. It never felt warm or gave any signs before it blew, no glasses coming from it, no noise.. just kaboom. I mean it was really loud. It blew pieces all around the place. Three months later while cleaning out my toaster I found a piece of the battery in it..lol. I'd love to figure out what happened. To this day I won't use a flashlight. I hardly even keep my cell phone on me..
Ghostguy6, Thank you.
 
Without any information on the cell itself we wont likely be able to find a cause. Since you mentioned Rayovac in your first post, I looked into their cells. They do not produce lithium rechargables nor do they have lithium AA cells or 14500 cells.

Based on the limited information at this point I would speculate either there was some moisture inside the flashlight that somehow reacted with the lithium in the battery or the cell went into thermal run away from the heat of the LED. I'm not familiar with that particular light so I cant say what the heat-sinking is like. Its possible the heat was going into the cell more than the metal body of the light so you wouldn't feel it.

Here is an exert from a paper I found on lithium cells

Normal aging in a lithium-ion cell may or may not increase the risk of a fire, depending on the type of degradation experienced by the cell. One such degradation method that leads to an increased risk of fire is lithium plating, where environmental factors or charging conditions can induce metallic lithium to form on the negative electrode within the cell. This metallic lithium can lead to internal short-circuit and subsequently thermal runaway if the short is the appropriate resistance to generate sufficient heat. However, capacity and energy loss during use can limit the amount of energy stored within the system, which would limit the energy release in the event of a failure (i.e. failure of a new system with full capacity may be more severe than an older/used system with only 50% available energy remaining).

Another non-energetic failure mode of lithium-ion cells may involve internal corrosion of cells or mechanical damage to cells, where electrolyte may leak from the compromised cells (Mikolajczak et al. 2011). Electrolyte leakage can lead to other problems (such as short-circuiting electronics that initiates larger failures), but the electrolyte itself presents concerns from a ventilation perspective. Lithium-ion electrolyte is typically composed of a mixture of organic carbonates such as ethylene carbonate or dimethyl carbonate (Mikolajczak et al. 2011). Such leaked carbonates are ignitable and may present a combustion hazard. Note, however, that leaked electrolyte is not an expected occurrence during normal operation of lithium-ion batteries and represents a failure of the cell(s) involved. In addition, many lithium-ion cells do not contain a substantial quantity of available liquid electrolyte that may leak out of a damaged cell. Furthermore, a volatile organic compound detector may be sufficient to detect a leak, and electrolyte vapor has a fairly distinct smell that can be detected by a person in the vicinity of such a leak.

Energetic failures in lithium-ion batteries have the potential to release substantial gas and, therefore, may pose a hazard that can be mitigated through ventilation.

Thermal runaway may result from electrical contact between the negative and positive electrodes. Thermal runaway occurs when the active materials within the cell have an exothermic chemical reaction, resulting in a rapid release of stored energy (Mikolajczak et al. 2011). This stored energy takes the form of both electrical energy (stored as chemical potential energy) and chemical energy (stored in the form of combustible materials such as the carbonate electrolyte) (Mikolajczak et al. 2011). A thermal runaway reaction in a lithium-ion cell occurs when the rate of heat generation of the cell exceeds the cell's rate of heat loss to its surroundings and the temperatures inside the cell are present for a sufficient time to initiate self-heating of the internal cell materials. The time it takes to initiate a thermal runaway reaction in a lithium-ion cell will depend on a number of factors, including the manner in which heat is generated by (or applied to) the cell, the cell chemistry, the state of charge of the cell, and the cell's surroundings. Thermal runaway can result in flammable gases being vented from a cell which can then ignite or lead to a potential explosion hazard. The vented gases can include hydrogen, carbon dioxide, carbon monoxide, and hydrocarbons such as methane, ethylene, ethane, propylene, and propane (Somandepalli et at. 2014).
The original can be found here
 
Without any information on the cell itself we wont likely be able to find a cause. Since you mentioned Rayovac in your first post, I looked into their cells. They do not produce lithium rechargables nor do they have lithium AA cells or 14500 cells.

Based on the limited information at this point I would speculate either there was some moisture inside the flashlight that somehow reacted with the lithium in the battery or the cell went into thermal run away from the heat of the LED. I'm not familiar with that particular light so I cant say what the heat-sinking is like. Its possible the heat was going into the cell more than the metal body of the light so you wouldn't feel it.

Here is an exert from a paper I found on lithium cells


The original can be found here
There is another light listed in the J5 website that runs in three AAAs or one 18650. I wonder if the incident happened with cell that was actually a Li-ion and nothing to do with Rayovac?
 
There is another light listed in the J5 website that runs in three AAAs or one 18650. I wonder if the incident happened with cell that was actually a Li-ion and nothing to do with Rayovac?
In his previous post he said it was a lithium AA cell. From the photo you can tell it was a Concealed Network edition of the J5. There is not much online about it but I found one youtube video that said it was an AA / 14500 version of the light. I too am a little confused by the Rayovac mention in the previous post by LoneWolf65. Either it was an alkaline AA or a rechargeable NiMh cell from Rayovac or it was a lithium from another manufacturer. Given that this incident took place on or around 02/03,2023 I don't think we will be able to get all the details. Given the severity of the incident I'm sure LoneWolf was not too concerned about the cell details when it happened and probably was more focused on the injury. Either way the I just hope Lonewolf made a full recovery without any serious effects.
 
Wow, no surprises there, Rayovac makes the leakiest alkaline cells, only logical their lithium cells would be as bad. That brand I will never buy or use.
 
This could be why the SF A19 and other cell extenders had a hole drilled in them to allow gasses to escape.
 
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