Bloated Battery in Tablet - Fire Hazard

Hi all

We have two wall mounted tablets and one old tablet as an alarm clock on the nightstand.
Yesterday I realized, that the one on the nightstand looks a bit deformed. I took it out of it’s cover and saw that the battery is totally bloated and deformed the case and the display already.
Unplugged, switched off, and put it outside during the night. Nothing happened (yet?) but I assume at some point this could be a big fire hazard if going unnoticed.

The tablet was rather old and is constantly plugged in. But it got me concerned of course: this could happen to any of the wall mounted tablets at any time I guess.
Ideally, I could remove the battery from the wall mounted tablets as they are always plugged in.

Did anyone else have an experience like this?
Guess checking these old devices from time to time is not a bad idea…

I have not made that experience yet but I know that a series of laptops in the company that I work for had that problem some time ago.
Google for swollen battery if you haven’t done yet and you will find several reports.

Indeed, I have faced this issue with my wall mounted tablets and have to say, those are not old ones but had been new when I installed them. Issue occured about one year after I bought them.
Doing some research I found out that it was a common problem with those kind of Alcatel tablets.

There have been some advices how to avoid the issue with bloated batteries :

  • Remove the battery and operate the device by power supply only. I have done this for one of them, which was not that easy, as It would not boot without a battery. Therefore I had to “fake” battery existance and connect the power supply with some additional parts to the internal battery connectors.

  • Charge the battery up to 60% only. This should prevent bloating. Not sure if this really helps, never tried it, as my devices do not allow to limit charging level with the common tricks and tools.

Thanks for your replies! Googled a bit yes, and found several reports. They often mention specific models (laptop, mobiles or tablets). Mine was a Samsung Galaxy Tab 4, also found some reports for that but I guess you’ll find reports of any device if you start looking for it :wink:

Was also thinking about removing the battery (not on this one, I won’t touch that one anymore…). Often tablets are sealed completely so that won’t be easy though.
So if anyone has specific models where that’s possible, I’m all ears.

Not really sealed, but you have to be carefull to not break the “snappers”.
I have bought myself a toolkit for opening devices with several different plastic tools.
This prevents dmaging the case.

Still got a few of these plastic tools lying around. Maybe I’ll try to remove the bloated battery and see if I can still use it :+1:

I had this happen to a work computer. I didn’t realize that the battery was located where it was so continued on with it for awhile, thinking it just had a cheaply made case and keyboard. Didn’t experience a fire but the IT guy who I finally took it to said I was lucky and should have brought it sooner.

Bet the brand of those laptops rhymes with “swell”.

Check ifixit to see if they have a teardown of your make and model. I’ve replaced batteries and screens in phones using instructions on that website. Some are easier to deal with than others.

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OK, found a similar doc and took it apart, wasn’t too hard. I removed the battery, really quite bloated :flushed:

At the moment, the tablet doesn’t start anymore as mentioned by @hmerk above. When started, a logo appears showing that the battery is overheating… We’ll see if there’s a solution for that to trick the tablet into thinking there is a battery.

Anyway, thanks for the discussion. Guess it’s good to raise some awareness on this.

This is quite common. Batteries might have an internal temp sensor.
You should have three wires coming from the battery pack, „Plus“, „Ground“ and „Temp“.
You can try to put a 10k resistor between „Temp“ and „Ground“.
But try at your own risk :wink:.

Bloating results from outgassing as the battery chemistry breaks down. As you noted, it can happen to any battery in any device. I’ve seen it with Dells, Macbooks, Android phones/tablets, iPhones, iPads…pretty much anything with a rechargeable battery.

Rechargeable batteries always swell a little bit when they’re being worked hard. If I recall correctly, the Samsung Galaxy Note fiasco a few years ago was caused by the batteries not having enough space inside the phones to allow for swelling.

Yeah, pretty much. Usually the seams will start to burst as the battery puts pressure on the device. Sometimes the screen will crack. If you have old devices in drawers, you might want to check on them periodically (or just recycle them).

Newer Samsung devices have a feature to limit the battery charging to 85%. It’s true that the last 10-20% of capacity has the most impact on a battery’s health/longevity, which is why charging intentionally slows down to a trickle as you near 100%. Whatever the case, every rechargeable battery has a life span.

It really is. A lot of people just continue using the devices, but it’s a serious fire hazard.

Depending on the device, you might be able to find a replacement battery. However, they’re usually lower quality than the originals (even when they claim to be OEM).

Well, I’ve got 6 wires but 3 different colors: 2x red, 2x blue and 2x black. So I’ll see if I can find some information about it and try my luck. Can’t do more than brick the device, right :slight_smile:

Thanks a lot for the details. Looks like you know that stuff well.

Right, I use that on my S22 as it still lasts a whole day.

In an ideal world, they would simply stop working instead of exploding :smiling_imp:

True, found a few offers. But for the stationary tablets, I will try to find a solution without a battery.

This is not unusual, you have two battery cells.
Try with the two blue wires and the resistor.
Black should be the Ground wires…

Famous last words :upside_down_face:
Thanks a lot, appreciate. Will probably try that, have to find a 10k resistor first and will probably do it outside, you never know…
And for what it’s worth: ChatGPT strongly discouraged me from trying that :sweat_smile:

Yup, but that’s what stored energy likes to do whenever given a chance. When you think about it, it’s a little crazy that an internal-combustion engine is basically an ongoing series of controlled explosions.

I have three Hisense cheap tablets on my walls already for 6 years. Always on, connected to usb charger.
Couple of years ago in one of them I found that battery was swollen. I just took cover off, removed the battery, put USB charger back on and it did work again, still OK.

In my opinion one of the reasons was that they did not have battery temp sensor - it was always showing 30 degrees C.

I bought one newer tablet from Lenovo for bigger display. There is an option to keep it charged at 60%, so I did so and it works for couple of years.

Another thing to consider - good USB charger. If the USB charger outputs higher voltage I assume this could cause battery charge system to malfunction. I use original Apple USB chargers for US market - they are very compact but quite sophisticated. Actually I’m afraid of fire due to USB charger too - therefore temperature protection is a must there.

I can tell you multiple stories: I’ve had swollen Batteries in various devices during the last few years. 2 different Smart watches, a wireless IP phone, a RC Helicopter toy, and a tablet. On one of the smart watches the entire back lid that can be removed for battery replacement fell off. Not a big surprise, it’s easy to remove. Same thing for the IP phone. The other smartwatch lost most of it’s battery life so I decided to replace it, I then noticed the swollen battery. The most interesting device is the tablet: The back cover is hard to remove but the battery just broke the plastic hooks that hold it, then it came off.

I took all those batteries outside and did various experiments with it: Hitting it with a hammer so it ruptures, pushing a screwdriver into it, cutting it open and so on. Not a single battery exploded, caught fire or got hot. So if someone knows how to make them explode/catch fire that’d be interesting to know. I thought any damage/contact with oxygen would cause a thermal runaway.

However, many years ago I’ve had a battery pack that exploded during charging and caused a fire. So those batteries definitely can explode. That was a multi-cell-battery though, all the other ones are single cell batteries. The exploding battery was from a drone and it wasn’t swollen or anything.

One of the many reasons I chose a 24" touch screen monitor + rpi instead of using a tablet on the wall.

Nope, or else we’d all hear about this a lot more. Fires usually happen when bloated batteries are compromised internally and effectively short-circuit themselves. If the batteries were depleted, then there wouldn’t have been enough energy if you short-circuited them (which you probably did when you punctured and cut them).

Batteries always get hot and swell a little when under load. That’s why this happened:

Your drone battery probably had a minor defect, and it’s pretty much impossible to tell if that’s going to be the case (since it’s all happening inside of the battery).

The USB 5V specification is +/-5%, so an acceptable voltage is anywhere from 4.75-5.25V. Since USB cables aren’t 100% efficient, many chargers provide a little more to allow for some power loss at the other end. 5.1V is probably the most common voltage.

Quick Charge and USB Power Delivery use higher voltages and amperages, but those levels should only be delivered when all three parts of the equation (charger, cable, and device) can handle them.

If you want to prolong your phone/tablet’s battery life, stick with low-speed 5V charging. It takes longer, but generates less heat and puts less strain on the battery cells.

I just assume that when the device stops charging (as battery is 100% full) some cheap chargers might not handle it 100% correct and increase the output voltage to 5.25V or beyond this limit. This might cause problem to charging circuit as it can’t block the voltage anymore and battery starts to be overcharged.