Why 18650 Battery Would Explode
As a very important invention in history, the emergence of batteries has indeed solved many problems, and the 18650 battery is the oldest but commonly seen Type. Since lithium battery still widely used at present, its safety is particularly important.
This article will introduce the knowledge of the 18650 battery and explain why there is an explosion. But First, Let’s take a closer look at the Charging and discharging of 18650 lithium battery.
Why Explain charging and discharging process and principle first?
Because 18650 Battery explosion happens when it’s charging and discharging.
1 18650 Lithium Battery Charging Process.
18650 Lithium battery charge control is divided into two phases.
The first phase is constant current charging. When the battery voltage is lower than 4.2 V, the charger will charge with a constant current.
The second stage is the constant voltage(CV) charging stage.
When the battery voltage reaches 4.2 V, due to the characteristics of the lithium battery, if the voltage is high, it will be damaged, the charger will fix the voltage at 4.2 V, and the charging current will gradually decrease when the current When it is reduced to a certain value (usually when 1/10 sets the current), the charging circuit is cut off, the charging completion indicator is on, and charging is completed.
Overcharge and discharge of lithium-ion batteries will cause permanent damage to the positive and negative electrodes. Excessive discharge leads to the collapse of the negative carbon layer structure, and the collapse will cause the insertion of lithium ions in the charging process; overcharging will cause too much lithium ions to be inserted into the negative carbon structure, causing some of the lithium ions to no longer be released.
According to lithium batteries industry standards, the nominal capacity is generally the minimum capacity. This capacity is determined At room temperature of 25 degrees, it is first filled with CC/CV 0.5 c and left standing for a while (It is usually 12 hours).
Discharge with 0.2 C current and discharge to 3.0 v (there is also another standard of 2.75 V, but the impact is not significant, since from 3v to 2.75 v, the battery will drop soon and not much capacity will be lost), the value of the released capacity , due to a certain number of batteries must have an individual.
The difference is the actual discharge capacity value of the battery with the lowest capacity. That is, the actual capacity of any battery in this batch should be greater than or equal to the nominal capacity.
2, 18650 Lithium Battery Charging Principle(From Chemical/Material Perspective)
The working principle of lithium-ion battery refers to its charge and discharge principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte.
The carbon as a negative electrode has a layered structure, and it has many micropores, and lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer. The more lithium ions are embedded, the higher the charging capacity.
In the same way, when the battery is discharged (ie, we use the battery), the lithium ions embedded in the carbon layer of the negative electrode escape and move back to the positive electrode. The more lithium ions returning to the positive electrode, the higher the discharge capacity. The battery capacity we usually refer to is the discharge capacity.
It is not difficult to see that during the charge and discharge of a lithium-ion battery, lithium ions move from the positive electrode → negative electrode → positive electrode.
If we compare the lithium-ion battery to a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium ion is like a good sportsman, running back and forth on both ends of the rocking chair. Therefore, the experts gave the lithium-ion battery a cute name rocking chair battery.
3, 18650 Lithium Battery Explosion (Actual Problems).
The vast majority of 18650 batteries are housed in a steel case, and batteries with poor quality, due to their lack of protection, can cause their internal pressure to suddenly increase when overcharged (overcharging), and explode when they exceed the acceptable value.
Problems such as short circuit, high temperature, or deformation or even puncture of the battery may cause the battery to explode.
In normal use, the 18650 batteries that get explosion are generally inferior batteries. The safety of regular lithium-ion batteries is actually quite good. The main reason that can cause the lithium battery to explode is that the battery with poor quality is prone to the internal short circuit during use.
When an internal short circuit occurs, it will generate high temperature and high-pressure gas in a short period of time, which is too late to be released through the exhaust valve. An explosion will occur.
After 30 years of development, the 18650 battery preparation process has been very mature, in addition to the performance has been greatly improved, its safety is also very perfect. In order to avoid the explosion of the sealed metal enclosure, the 18650 battery is now equipped with a safety valve at the top.
The safety valve is standard for every 18650 battery and is the most important explosion protection barrier. When the internal pressure of the battery is too high, the top safety valve will open the exhaust decompression to avoid the explosion.
However, when the safety valve is opened, chemical substances leaked into the battery will react with oxygen in the air under high-temperature conditions, and there is still the possibility of fire.
In addition, some 18650 batteries are now equipped with protection board, with overcharge and over-discharge and short circuit protection and other functions, safety performance is very high.
Want More Details: Download our battery design ebook.Lithium Battery Design Design Ebook Download(2M, 20 pages, PDF)
Well, we have discussed about the charging process and charging princeple of lithium battery and talked about some actual problem of battery explosion.
We can easily know that,
Almost lithium-ion battery catch fires and explosions because of short circuiting which will happen when the plastic separator fails and lets the anode and cathode touch togethor. And once those two get together, the battery gets short circuiting. And then the process of short circuiting will generate a lot of heat. Once the battery temperature over the limitation, battery will catch fire or explode.
There are some main reasons which will cause lithium battery short circuiting:
1.Bad Manufacturing Design:
Like Some easily-exploding battery brand, bacause of poor design, there was not enough space for separator and electrodes inside the lithium battery. We know that the separator is between the anode electrode and cathode electrode. If there was no enough space for separator and electrodes, short circuiting will easily occur. Even a well designed battery can fail if quality control isn’t kept tight enough or there’s some defect in manufacturing.
2.Thermal Runaway and Multiple Cells:
While not relevant to single cell batteries like those found in most smartphones (the iPhone X actually has two cells), only one battery cell needs to fail for the whole battery to go. Once one cell overheats, you get a domino effect called “thermal runaway.” For batteries with hundreds of cells—like those in the Tesla Model S—thermal runaway has the potential to be a really big problem.
3.Charger Problems:
A lithium ion battery also can be damaged by a poor quality charger. According to our daily experence of charging a battery, we easily find that the charger will generate heat. If the charger short or generate two much heat near the battery, this hot charger can do enough damage to catch fire. That is the reason why we suggest people using offical chargers. Lithium-ion batteries do have built in protections to stop them overcharging. While very rare, if these safety precautions fail, overcharging is a good way to overheat a battery.
4.External Factors:
Extreme heat is nearly guaranteed to cause a failure. Batteries left too close to a heat source—or caught in a fire—have been known to explode. Other external factor can cause a lithium-ion battery to fail, too. If you drop your phone too hard (or too many times), there’s a chance you’ll damage the separator and cause the electrodes to touch. If you pierce the battery (either by accident or deliberately), then you’ll almost certainly cause a short circuit.
What is the best way to safely prevent a 18650 battery from exploding?
To start with, do not over charge it. What you need to know is that the highest charge voltage of a bare 18650 cell is 4.2V, so do not charge your lithium battery witch a 4.35V charger, even though there is just 0.15V higher than 4.2V. You’d better charge your dear 18650 battery pack/cell with a matched charger which can prolong battery life.( for lifepo4 battery,
Secondly, do not put two terminals together which will cause short circuit. Both of the two terminals just like shorttube lycoris, positive pole can not see the negative pole. Once they touch each other, battery will die and release a large amount of heat which will increase the risk of explosion.(PS: when your battery have a pieriod day-off, you’d better put lithium batteries in plastic cases and keep these batteries alway from loose change, keys and any other metals which are conductive.)
Thirdly, be careful with your 18650 cells. Just like a infant, you can not drop it, you can not pierce it with needle, you can not drawn it in the water. You just need to protect it from all physical damaged.
The last but never the least, plz purchase good cells like us DNK POWER. We stick to provide safe chemistries such as Lithium Cobalt Oxide cells
4 Choose Branded 18650 Battery Charger
From consumers end, One of the important things we can do to avoid possible 18650 battery explosion is to buy high-quality battery charger?
The Easier way? Buy Branded chargers.
Some chargers that customer buy are made using inexpensive charging Chips/Designs and are not good enough in sending out accurate current, which can easily cause abnormal battery charging and even damage the battery. When choosing the charger, try to choose the top brand of 18650 lithium-ion battery charger, they have good quality control, and after-sales service, and thus can extend your battery life.
Branded 18650 battery charger has four basic protections: short-circuit protection, over-current protection, over-voltage protection, and battery reverse protection.
Over-Charge Protection: When the charger overcharges the lithium-ion battery, it needs to terminate the charging state immediately to prevent the possible internal pressure from rising since the internal battery temperature will rise if the battery is charged full already.
For this reason, It’s also suggested that a protection IC on the BMS of the battery is required to monitor the battery voltage. When it reaches the battery overcharge voltage, it activates the overcharge protection function and stops charging.
Over-Discharge Protection: In order to prevent the over-discharge status of the lithium-ion battery, when the lithium-ion battery voltage is lower than its over-discharge voltage detection point, over-discharge protection is activated, the discharge is stopped, and the battery is maintained in a low quiescent current standby mode.
Over-Current and Short-circuit Protection: When the lithium-ion battery discharge current is too large or a short circuit condition occurs, the protection device will activate the over-current protection function.
For lithium batteries, the reason for the explosion will be understandable, after all, in the past, the stability of the grass will not be so severe, but the 18650 as a very high-performance lithium battery, its application is certainly Will become more and more extensive, after all, in terms of such indispensable batteries, 18650 lithium battery is the best choice.
5. 3 Storage Tips for 18650 Battery
The most important storage condition of 18650 lithium battery is temperature and humidity. Generally, room temperature has little effect on the performance of lithium battery, but there should be no direct sunlight. High temperature can easily cause the model lithium battery to bulge or explode.
Here are some storage suggestions:
1. Do not put the 18650 lithium battery into the water, or use the battery in a humid environment; do not store the battery when the ambient temperature is higher than 65 °C.
2, the best charging environment for lithium batteries is at 20 ~ 26 ° C, please do not charge outdoor high temperature in the summer noon and low temperature outdoor charging in winter night. If the temperature is too high, it is easy to overcharge. If the temperature is too low, it will easily lead to low voltage, which will have a bad effect on the performance and use of the lithium battery.
3. If the lithium battery is not used for a long time, please take out the lithium battery and put it in a cool and dry place. If it is stored for a long time, charge the battery to 40% and store it.
6. 4 Tips for 18650 Battery Manufacturer and Engineers
The safety problem of 18650 lithium-ion battery is burning or even exploding. The root cause of these problems lies in the thermal runaway inside the battery. In addition, some external factors such as overcharge, fire source, extrusion, puncture, short circuit, etc. Will cause the battery to explode.
We here come up with some tips for battery manufacturers and enigineers.
1, 18650 lithium battery electrolyte and positive and negative electrodes have high reactivity, especially at high temperatures, in order to improve the safety of the battery, improve the safety of the electrolyte is one of the more effective methods. The safety hazard of the electrolyte can be effectively solved by adding functional additives, using new lithium salts and utility model solvents.
2. For the 18650 lithium battery anode material, since the surface is often the most prone to thermal chemical decomposition and exotherm in the lithium ion battery, improving the thermal stability of the SEI film is the key method to improve the safety of the anode material.
3, the installation of battery safety valve, thermal fuse, series with positive temperature coefficient components, the use of heat-sealed diaphragm, loading special protection circuit, dedicated battery management system, etc., will also enhance the safety of 18650 battery.
4. Lithium batteries will release heat during work. If they are too late to release, they will spontaneously ignite and explode. It can be managed by a battery thermal management system, which is a subsystem in the battery management system that enables the battery to cool when the temperature is too high, while the temperature is low. Then preheating is performed, thereby better exerting the performance of the battery.
With the advancement of the times, the development and manufacturing of lithium battery materials technology will continue to improve. It can be foreseen that under the continuous development of battery technology, lithium batteries will become more and more secure, and consumers do not need to worry too much about safety.
Related Post: Why does Lithium Battery Leak and How to Deal with it?
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Thank You a life savor I have recently bought energy batteries from EBAY out of 300 batteries one overheated the minute I hooked it to the bank.I charged another battery and it overcharged and exploded in my face luckily I was wearing glasses.I was checking another wanting to know if it actually was 10000mah it blew up ? testing now I found your article and I understand much more and closer to building a safer 12vdc battery for my camper.
Thank You so much for this Life-Saving Article God Bless.. wantfithammerit@EBAY, HOBBYIST AND VETERAN.
thanks for your feedback, it’s our pleasure that the post can help you
Realize that most 18650 batteries advertised over 3500 mAH are probably dangerous FAKES. If they come from China (most do) be sure to find a US company that backs and warrantees the specifications. Getting cheap Chinese counterfeit batteries is very dangerous. All 9000 mAh are for sure FAKEs and I have seen some tested and they show only 750 mAH. I wont trust any Chinese vendor direct on any battery. I have used US companies with a clear return policy if the batteries do not test. Chinese vendors like to state ‘free returns’ but in the fine print you pay shipping to some rural address in China that costs multiples you pay for the crap dangerous junk they pedal. I have seen stories of some that dissect these so called Chinese super batteries to find a smaller battery hidden inside with sand filling most of the case.
super correct
There is insufficient discussion of what happens when an UNprotected cell is over-discharged during TYPICAL use. For example, a flashlight left switched-on.
This is a REAL-LIFE scenario, and 2 lithium cells in a parallel configuration is VERY common in LED headlamps. What exactly is likely to happen if 2 UNprotected cells in parallel are in an LED headlamp and the headlamp is left switched-on too long while the user is wearing it?
(note: these cheap LED headlamps typically purchased and used do NOT have any automatic switch-off function when the lithium cell voltage gets too low. The LED just keeps getting dimmer and dimmer is the only “warning” provided and in some situations will not be obvious until lithium cell voltage is well below 2.5 Volts. Also, there usually is no advice in the LED headlamp documentation that advises using self-protected lithium cells)
From our experience, there is no explosion when batteries are over-discharged, as the battery would be dead then. however, if you are over-charging the batteries, it might explode if the BMS is not working properly. This happens when you are using batteries that are just too cheap.
This is good stuff that any 18650 user should be aware of.
Good job.
Would leaving 18650 battries (in flashlight) be recommended because of high temps of car in Georgia summers?
please refer to your specifications of the battery, it has all the details.
PS: in our experience, no flashlight battery manufacturer would make battery that can be used at high temperature(up to 80°C) environment.it will need special formula on the battery cell itself and price could be much higher(at least price will be double).
in general, battery are suggested to store or be used under 55°C
can you recomend a charger, for my powerwall that i am building it will be 14.80v 4p70
Our recomandation is to buy branded(top 10) charger.
So you can google “top 10 powerwall charger”
“top 10 18650 charger”
“top 10 36V charger”
“top 10 ebike charger” etc
we recommend to read articles that are not affiliated (like amazon) or sponsored.
What does overcharge mean? At what voltage and for how long a battery may explode? If I continue apply 5v, 0.2 A to a full battery for 10 hours, will that make the battery explode?
Hi Steve,
please always refer to your user manual, it’s really hard to decide, let’s say, for a 5V 100Ah battery, it won’t explode, if for a 5V 1Ah battery, it may a danger if no over charging protection included.
over charge protection can be from charger as well as battery, so if you cann’t decide if the battery has such protection, you can always rely on branded chargers.
I have inserted 2 18650 rechargeable batteries by ultrafire into the charger sent with the batteries ( from amazon). A blue light shows for each battery. How long should I charge them? Will the light color change when charged?
it really depends on the charger, please always refer to your ultrafire charger user manual
PS: in common sense, blue light means the battery is full already, red means the battery is charging.
Why not just replace a 5v 3A 18650 battery in a work light with an ordinary rechargeable one?
you can replace primary battery with rechargable lithium 18650 battery, so long as the voltage is the same
Hi, i was just wanting to make sure I was storing the 18650 batteries correctly – in a battery case, the positive ends should all be facing the same way right?
that’s a good way to store them.
what’s the chemical reaction for extracting lithium from spent lithium ion batteries
we will write a post on this, stay tuned.
I have 18650 DIY battery bank case . When it was charging 2×18650 =2×2200 mah sony battery, it takes 4200 mah approx 6 hrs for full charging, when it discharging it takes 2hrs, when I charge through my phone I get only 65% battery for 1st charge , My phone has 3400mah capacity.
What’s happening
all batteries can’t be discharged 100% when BMS included, for power bank, it will lift the battery cell voltage of 3.7V to 5V, there is energy loss in that phrase, overall, 3400mah as DIY project is still good to go.
Hi. I was just reading your article about charge characteristics. I have some solar/USB camp lanterns that came with 2×18650 soldered in parallel. Not sure whether it is safe to have them charge & discharge in parallel
Use 18650 chargers that is specially designed for 18650 and has features of over charge protection(give more budgets if you want to keep safe)
does 18650 batteries explodes if youre not charging or not even using? coz i got 3 18650 batteries at my home but i cant get them coz i dump them do they explode?
There is no need to worry about that
Hi, I leave my laptop plugged in and don’t use the battery. I’m not sure what kind it is.
Is this safer?
Please let me know.
please follow the instructions of the laptop user manual, most of the time it’s safe.
can i charge a 18650 to a direct small solar 5 volt panel
please don’t charge 18650 cell at 5V panel, the end voltage for 18650 battery is 4.2V, please always use the correct charge to charge batteries(any batteries will apply this rule)
i own a couple of 18650 samsung batteries
that kind for e cigs
yesterday i accidentaly sank them in alcohol
the alcohol evaporated since yesterday and today i fully charged them
my question is..is it safe for me to use them?
the kind of alcohol that i dropped them into is 70% medicinal alcohol
i m kinda afraid since i don t want them to explode :-??
since alcohol can be evaporated quickly, so no problem to go on use them.
if you are still worried, buy new ones.
i just had an IMR 18650 battery explode in my LUC V4 charger. It caused alot of damage in my house including but not limited to over 20 burns in my carpet and many black marks on my ceiling. I have been using this charger for a couple of years and it has performed perfectly until now. Im just not sure if it is a charger problem or a battery problem. The battery vented shot to the ceiling then exploded like an airburst missile. it was actually pretty cool despite all of the damage. do you know what’s wrong with the battery?
maybe there is some problem with the IMR 18650 battery(fake batteries or manufacuturing defects etc)
im just confuse in my battery because some battery may be explode
how to avoid the explosion?
im using 3 pcs 18650 battery for my vape
everyone is talking about fake battery, but what brand is not fake?
there are many ways to define it’s fake or not
1 google: how to check xxx fake battery
2 use youtube/tiktok
3 check with the battery manufacturer or vendor
I value safety first, so my first question would have to do with making sure I don’t get a model that might explode
Do you know any resources that could point me to past instances when the IMREN 18650 battery has exploded?
please google words like “IMREN explosion”, or check some popular battery forum, and make your own decision to use it or not.
PS: there are many cases to cause battery explosion, even samsung has many explosion, so no need to be over-sensitive to it.
JUST TRYING TO FIND OUT IF THAT MY7.4V 1500MAH IS GOING TO EXPLODE
ITS GETTING PRETTY BIG AND IT GOES TO A DRONE THAT IS PRETYY NICE AND DONT WANT A FAILIER
please dont use batteries that are bulged. simply replace them
this is quite important for drone batteries, as it requires high discharging current.
be careful.
My 18650 batteries are in a 4 series to run a small vacuum. They seeed to work OK. So I charged with the vacuum charger 26v 2500ma now they get hot and run down in seconds.
Apparently you are using the wrong charger, correct charger should 16.8V charger
So please always refer to your user manual and buy the correct charger.
The bottom line, check your battery label, it has all information about the battery input.
I want to ask what reason can cause 18650 li battery exploded
cause the high discharge make li battery 18650 explode?
Abnormal charging can cause internal pressure of the lithium battery to suddenly increase when overcharged (overcharging), and explode when they exceed the acceptable value.
Problems such as short circuit, high temperature, or deformation or even puncture of the battery may cause the battery to explode.
could please tell me some information on how the 18650 Lithium-ion batteries could damage or explode? If so I would be very grateful, currently I am working on a project containing these batteries so I am a little concerned. Thank you!
see above answer
can i use a 10 WATT SOLAR PANEL to charge 2 18650 3400 mah batteries inside a surveillance camera?
If Your surveillance camrera user manual states 18650 battery is OK, then go with it.
the botton line is your replacement battery should have the same volatge as the original battery
yes how badly can a new 18650 battery explode
the worest case, it can cause the house burn down. so be careful to follow guidance of your batteries.
Yes I have purchased 24 sanyo 18650 3500 10A batteries and they are unprotected. I may need many more like this but im not sure i can use unprotected
it depends on your design, you can send us your final application to our email sales@www.dnkpower.com and we will take a look
The terrible smell caused from one of these battery explosions, is it even safe to be in the room afterwards and to breathe in whatever chemicals was just let into the air?
there is no such report it will do harm to our health so long as the window is open
Excellent source of information. Keep up the good work.
Our Pleasure
Hi. My 18650 battery shows a voltage of 2 v and the charger cannot charge it. Because the volts is below the safe level. Is it possible to bump up the charge using a separate 6 volt battery to raise the voltage to above 2.7 volts so that the charger will accept it and charge? Is it safe?
in our testing, if you are using 6V to charge the 2V battery, it will not be charged, instead you should use chargers like 3V 100mAh charger, (notice here we are not using 4.2V 18650 charger, as it won’t charge for 2V battery)
for batteries less then 2.5V, we suggest to use voltage that just a little above it and at tricle charging(0.1A or even less ), when the voltage goes up to 2.75V, you can use normal 18650 chargers.
above is for correct charging method of batteries less then 2.75V, as long as safety concerns, we normally don’t suggest customers to use batteries that’s only 2V, as it might be dead battery.
How do you dispose of 18650 3.7V 3000mah batteries? I found 2 in an apartment that I rented out. Don’t know if they’re charged or not.
The easy and responsible way to get rid of them is to find the nearest store/agency that has a battery disposal or battery collection area and drop them off there
I have purchased 100 Panasoinc 18650 batteries and What I am going to do is to use them in a detap vmount battery for cinema cameras and gimbals
i dont want to cause my expensive equipment to explode
what can i do please
Please check your cinema cameras and gimbals user manual about the correct parameters of the battery/power supply
Make sure it meets all the requested parameters includes battery voltage, working current etc.
Silly question, but just trying to be safe , I have a EFEST LUC V6 charger for 18650 batteries for my Vape
I also just bought a flashlight that also runs off of 2x 2600 mah batteries, is it safe to say that this charger will charge them without any problems?
It is charging the batteries right now as i text
This charger I’m sure you are knowledgeable with this charger, it has a safety mechanism that stops charging at 4.20v I am keeping an eye on it , I’m sure it will do just fine I’ve charged others like it just thought I’d ask since I saw this article or site rather when I Googled it
Ok, thanks anyway
if the 2* 2600mah battery charging end voltage also 4.2V as the V6 charger, then it’s good to go
I had a battery explode and the smell is awful. Is it even safe to be breathing this in??
That awful smell is not that bad to influence your health, but why not stay in clean air and you can have your rest of your day happy mood.
Want to know if you can use the 18650 3500mAh 3.7 battery in the SMOK ARCFOX SAFELY
Think its lithium battery
Will they explode
the SMOK ARCFOX should have requirement for it’s battery, please refer to the manual or specifications
I went to a Batteries Plus specialty store to buy 18650 batteries for my new headlamp and was told that these batteries are way too powerful and dangerous for that kind of use. He refused to order them for that use. Comments?
in that case, please buy the battery from the headlamp vendor.
hi, how many BTU of heat energy are given off when a fully charged 18650 battery burns?
since 1 W is equal to 3.41 BTU/h. so 18650 2.6Ah battery is 32.8 BTU and 3.5Ah battery is 44.1 BTU
Is it dangerous to short a 18650 battery on a human?
I did it on mishappen. Now im scared of heart freaquenzy
no need to worry about that, The rule of thumb is 50 VAC or 120 VDC is considered the danger limit,so it’s quite safe for you to short one signle 18650 battery cell on human
Hi, im looking to buy some 18650 batteries, the ones i have are a few years old now and one exploded yesterday, i have been told to buy 30q batteries and am wondering if these are what i need and what the 30q means. Thanks
it’s better to check the application and see which may fits best
I was just wondering if my battery would explode from sitting in my bag unused
no worries, as long as you don’t throw the batteries in fire or heating them, no fire, no explosion