How to prevent a lipo battery from swelling

How to prevent a lipo battery from swelling

The RC LiPo battery swelling problem may have been bothering you. In our previous article, video explained why batteries swelling and failures. Lithium polymer (or lipo) batteries have a higher energy output than standard lithium batteries, they are primarily used in drones and RCs.

However, the battery pack inside a lipo battery can expand for a number of reasons, including heat, overcharging or over-discharging, and cause a fire or even an explosion. While all lipo batteries will naturally expand at some point, there are some ways to extend their life and ensure their safety in use.

Expansion of the battery has a certain risk, once the battery swell, the best is to stop using, so as not to cause other damage. Therefore, from the time we buy the RC lipo battery, we must start to prevent battery swelling and take some protection measures.

How to prevent a lipo battery from swelling

Table of Contents

Here’s a list of a few ways for you to prevent it.

Use a high quality charger.

Use a charger with high visibility. Basically, the charger will keep the current or charge rate constant until the battery reaches its peak voltage (4.2v per cell in the pack). It will then maintain that voltage while reducing the current. On the other hand, NiMH and NiCd batteries are best charged using the pulse charging method. Charging LiPo batteries in this way can be a damaging effect, so it is important to have a LiPo compatible charger.

Choose a charger with a balancing feature. This feature ensures that each battery releases the same amount of power, helping to improve battery performance and avoiding premature signs of battery weakness. There are actually many functions that the RC charger can have. If all the functions are integrated into one charger, the volume and weight will bring a certain degree of drag.

It is worth mentioning that Gens ACE‘s new IMARS III charger has the functions required by ordinary chargers, weighs only 0.4kg, is exquisite and compact, and is convenient to carry out.

How to prevent a lipo battery from swelling

Avoid overcharging and discharging.

Our previous experiments with overcharging batteries resulted in severe bulging, although the batteries did not explode. Overcharging and discharging are very damaging to the battery and may cause destruction of the electrode active material and loss of responsiveness.

Use and store the battery at room temperature.

Always store lithium polymer batteries at room temperature. Do not charge devices in direct sunlight or near a heat source, and do not store them in a hot garage or in a cold environment. LiPo batteries naturally get hot when used or charged, so before using or storing them, you need to give them some time to cool down and get them in normal as well as optimal condition.


The discharge of the battery is obtained by the reaction of substances inside the battery, and all extreme means will affect these substances and the effect of the reaction. Taking the right approach to use can bring you more energy, but also save costs and continue to power your devotion.

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How to prevent a lipo battery from swelling

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How to prevent a lipo battery from swelling

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How to prevent a lipo battery from swelling

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Lithium-ion and lithium polymer batteries have many advantages, such as a high energy density and long battery life. But there is also a disadvantage: lithium is a lot more reactive than most of the substances found in other batteries. The battery’s cells can produce a gas when overheated, and the pressure caused by that gas causes this odd swelling.

How to prevent a lipo battery from swelling

One symptom, many causes

The gas is produced if the battery gets too hot. This may happen if you charge the battery too often, if your battery is overused, or it may be the result of a production flaw or of using the wrong or a defective charger. Worried? There may be no immediate cause for concern. Devices with lithium-ion and lithium polymer batteries normally have built-in safety functions such as heat sensors and a network of circuits to prevent overcharging. Moreover, lithium ion and lithium polymer batteries have a sturdy casing. As a result, the gas cannot escape.

There is no point waiting for the battery to “shrink”. The ever growing pressure can cause damage to the entire device.

First aid for battery bulges

Turn your device off if you have any indication of swelling and take it to a service centre. There is no point waiting for the battery to “shrink”. The ever growing pressure can cause damage to the entire device. Leave the battery in the device only if it is stuck. Never try to “solve” the swelling yourself by pricking a hole in it or with any other creative stunt. That is very dangerous: not only is the gas flammable, but also toxic. The service centre will ensure that the battery ends up reaching Bebat.

OK, I’m flying some Turnigy 5000s in a 700 sized heli. 12S setup, composed of 2 6s packs. The outer cells ONLY in some of the packs are getting puffy. I mean really puffy. But they still fly GREAT.

I had a Turnigy 3000 (for a different heli) that got so puffy, and so old and tired, I decided to cut it open. Within the outer wrap, the pack itself was still a perfect brick. Kinda surprised me.

Therefore comes a question: Since my 5000 packs are still flying just fine, yet one of them is so puffy it no longer fits between the frames, what happens if I:

1) Pinhole the outer bag without touching the inner brick
2) Squeeze it flat
3) Seal the hole.

Now, I know there will be a bunch of folks who say "Don’t Try It"! just based on general paranoia around LiPo batteries. So, let’s assume that I have a totally safe place to charge, store, transport this pack. I will do it as an experiment. What do folks who ACTUALLY KNOW SOMETHING about LiPo chemistry and construction, and/or who’ve ACTUALLY TRIED THIS.

Yeah, I know, this is the internet, and just because I ask the question doesn’t mean I own/control the thread. but. to the best of our ability, let’s skip the uninformed speculation and focus on what is KNOWN about degassing a cell?

You can not de gas a cell.

You state you had puffy cells but when you openred the wrapper the cells were firm.

If the cells are puffed they are history.

I have never seen an air tight heat shrink covering on a LiPoly battery.

You can not de gas a cell.

You state you had puffy cells but when you openred the wrapper the cells were firm.

If the cells are puffed they are history.

I have never seen an air tight heat shrink covering on a LiPoly battery.

We must not be communicating.

The cell that I am considering degassing is not "history", it flies just fine. I’m not talking about Heat Shrink, as on the pack. I am talking about the actual silver bag of the cell itself. That is what I would puncture and reseal.

When I cut open the individual cell in that other pack (of the same brand), I opened the actual silver bag. The inner workings of the cell were absolutely square and firm. Just the silver bag had inflated. That cell was old in cycles, and ready for discard (the reason I cut it open). The cell that I’m considering degassing is still pulling hard, flying fine.

OK do what you feel is proper. LiPoly cells are sealed for a very good reason. I have read of all kind of saves such as freezing, strghting a curved one by placing a board on it and parking a car on it over night. Sealing holes / tears with hot gle,goop etc.

I have never owned a LiPoly that was worth risking, aircraft,equipment,house,shop, automobile or human lifes over. They are not the safest form of energy under je best of the best of conditions and damaged they are even less safe.

This is my last reply on this issue.

OK do what you feel is proper. LiPoly cells are sealed for a very good reason. I have read of all kind of saves such as freezing, strghting a curved one by placing a board on it and parking a car on it over night. Sealing holes / tears with hot gle,goop etc.

I have never owned a LiPoly that was worth risking, aircraft,equipment,house,shop, automobile or human lifes over. They are not the safest form of energy under je best of the best of conditions and damaged they are even less safe.

This is my last reply on this issue.

Thanks for the input, Charles. I have tremendous respect for the technical info you’ve posted over the years, and know you have a lot of data and a lot of expertise. With that respect in mind, let me, in turn, respectfully point out that you have no idea how I will treat this pack if I engage in this experiment. I can assure you that no houses, cars, or aircraft will be put at risk until I cycle the pack many times. Meanwhile, it will be stored in a flameproof bunker on my acreage property, well isolated.

Are there any facts related to the specific procedure I’m considering? I’m trying to find out if I’m wasting my time because this process has been tried and always fails. VS. no one has ever tried this based on general assumptions about LiPo safety.

Here is another thought: Do we have PROOF that the pack is more or less dangerous in its current state, or with pressure relieved? I certainly don’t know.

So, assumptions? Or Data? If data, please share. If assumptions only, it would be grand if that were your last post on this question.

How to prevent a lipo battery from swelling

My cousin recently came to me with a battery problem. He got a drone for Christmas, and he had not opened it for a while. “Last Christmas, right?”, I asked. Apparently, it was the Christmas before (i.e a year and a half of being in a box). “Uh-oh,” I say. I almost knew what was coming. The drone obviously did not work, and I got to see a picture of a very bloated Lithium Ion pouch cell. Your Lithium-Ion battery does need some attention from you every few months in the form of a periodic recharge, or you will end up with a cell that looks like the image below. (My colleagues have brought me plenty of gadgets with the plastic case popped open from a bloated battery)

How to prevent a lipo battery from swelling

Lithium-ion cells can swell due to many reasons, but somehow the issue of deep discharge swelling and the related hazards with charging such a battery seem to be widely underestimated.

Common causes of battery swelling include:

  1. Overcharge conditions which accelerate parasitic reactions between the electrodes and electrolyte, with release of heat and gases.
  2. Poor cell quality and design with low anode to cathode stoichiometric ratios, particulate contamination
  3. Mechanical damage to electrodes induced either during cell assembly or from the product application
  4. Excessive temperatures (Do not leave your cell phone inside your car)
  5. Deep discharge of cells

Anything that increases the self-discharge rate of a battery is bad (including poor manufacturing quality, and exposure to heat) and allows your battery to go into deep discharge quicker.

The CT scan below shows severe jellyroll distortion from gassing due to deep discharge. As you can imagine, a battery such as this one would not work very well.

How to prevent a lipo battery from swelling

CT scan of battery from deep discharge swelling (Image Courtesy of DfR Solutions)

A deep discharge condition can also create safety hazards. When a lithium-ion cell goes into deep discharge, it is in a highly de-intercalated state (The word intercalate means to insert between layers in a crystal lattice). In a lithium-ion battery both the anode and cathode have ‘cubbyholes’ for the lithium-ion to shuttle back and forth. When the battery is deep discharged, the protective passivation layer on the anode called the Solid Electrolyte Interphase (SEI) layer decomposes, with new electrode and electrolyte surfaces coming in contact and new SEI layer is formed. All of these reactions lead to gas formation.

How to prevent a lipo battery from swelling

Figure 2: Mechanism of Deep Discharge in a Lithium-Ion Battery (Reproduced under Wiki Commons license from

The copper current collector on the negative electrode also starts to dissolve as shown in Figure 2. Upon recharge these copper ions deposit on electrode or separator surfaces potentially leading to a copper short and the risk of thermal runaway (Battery folks call this an event, while normal folks call this an explosion).

Such a deeply discharged battery should not be recharged and a deep discharge voltage cutoff must be implemented in the battery protection system by the device manufacturer. This can include a trickle charge till a certain threshold voltage is reached within a given time and ramping up charge subsequently. Failure to reach the voltage threshold in the given time, would classify the battery as damaged and shut it down, preventing it from being used.

What can you do as a consumer to prevent a bloated battery situation? Do not buy cheap batteries, where you are not in a position to assess cell manufacturing quality. Do not buy aftermarket chargers, where protection adequacy is unknown. Do not expose your batteries to high temperature. And lastly, if you do get a drone (or other electronic gadget) for Christmas don’t wait for a year and half to open it – your battery does need a periodic recharge.

Join us on October 10th, 2019 for our webinar Mitigating Risks of Lithium-Ion Pouch Cells: Common Mistakes and How to Avoid Them presented by Vidyu Challa by clicking the registration link below!

My 2 year old lipo 11.1 V 20c 2100mAh battery for my fly zone sensei plane has begun to swell, still holds charge , I have many flights with battery, is it still safe to fly??

any advice would be greatly apreaciated,

The best answer is no. But, if the swelling is minor, it may still have some life left.
It depends a great deal on how much swelling. I’d also say that 3s 2100mah batteries are not expensive, and replacing the battery is good insurance.

How do you charge the battery, and how is it stored?
Both can have a great deal to do with how long a battery can be used, and if it swells or not.

As a comparison, I have several 4s 3300mah lipos from different mfrs. The Hyperions and one of the E-Flites are interesting, in that two have swelled to beyond what I consider safe use for flight, and three have not. Other brands of this size are mixed, in that one has slight swelling, and a couple of others no swelling, but have cell balance issues. All are at least one season old, with the oldest three seasons. A large mistake you might make is to store the lipos at full charge, or depleted. 3.85V per cell is the preferred long term storage voltage.

I thught the hobby battery companies all built to a standardized code of quality.

if the cells keep! their V, so no drifting and the swelling is minimal you might! use it but under strict observation for and after flight.

i just disassembled a 5S pack with only 20 flights with no visible puffing, but cell 3 was already bursted at the end and only visible after opeing the pack.

only indicator was that cell 3 did not keep it’s V.

A puffed LiPo is a sign of damage from a few causes such as over-capacity discharging (flying the battery for too long), over-current discharging (drawing too much current from the battery – unlikely in your case since you’re flying with the motor/propeller it was intended for) or simply many cycles and it’s naturally nearing the end of its life cycle.

A puffed LiPo means the internal resistance has built up so it will not be able to deliver maximum voltage during a flight.

Many people use slightly puffed LiPos, they just aren’t working to their maximum capability. Severely puffed LiPos can also be dangerous. If your battery still flies the plane and isn’t severely puffed it’s probably okay. Just keep an eye on that one and monitor while charging and store properly (good advice for all LiPos).

If you plan to fly the plane much probably should pick up a few new batteries.

Swollen LiFePO4 batteries are the result of too much current inside a cell of the battery, which causes a build-up of heat and gas. This can be caused by overcharging, deep discharge, overheating to battery or manufacturer defects, or environmental reasons. In this article, we discuss why that happens and how you can prevent that.

LiFePO4 battery swelling is one of the important physical characteristics before LiFePO4 battery failure. Sometimes LiFePO4 batteries puff/swell up to twice their original size. Worst case – they can explode.

What Causes a Swollen LiFePO4 Battery?

Causes of swollen LiFePO4 batteries

  • Abuse like over charge, over discharge;
  • Environmental reasons like high temperature, high humidity, ultra low pressure;
  • Production process reasons.

1. LiFePO4 battery swollen caused by overcharge

Overcharging will cause all the lithium atoms in the positive electrode material to run into the negative electrode material, resulting in the loss of lithium atoms in the positive electrode, which is also an important reason for the decrease in battery power. In this process, the positive electrode has fewer and fewer lithium atoms, and the negative electrode has more and more lithium atoms, which will cause the battery to bulge.

2. LiFePO4 battery swollen caused by over-discharge

LiFePO4 batteries will reversibly damage the passivation layer covering the surface of the battery after excessive discharge. The destruction of the passivation film that protects the negative electrode material will damage the negative electrode material and cause the battery to bulge.

3. The problem of production process

Lithium-ion battery bulging may be a problem in the production process of lithium iron phosphate batteries, because the electrode layer is uneven and the production process is relatively rough, resulting in battery bulging.

4. Long-term idle

If the battery is not used for a long time, swelling will also occur, because the air is also conductive to a certain extent, so the battery is placed for too long, which is equivalent to direct contact between the positive and negative electrodes of the battery, causing a chronic short circuit.

Can Swollen LiFePO4 Battery be Replaced?

There are two reasons for the swelling of lithium batteries:

One is the reversible deformation caused by changes in the positive and negative materials;

The other is the irreversible deformation caused by the gas generated inside the lithium battery.

Reversible deformation has always been accompanied by the cyclic charging and discharging process of lithium batteries. Irreversible deformation occurs under abuse conditions, such as overcharge, overdischarge, and overheating.

Those who make use of Lipo batteries will most likely come across a swollen or probably a puffy looking battery.

While most people wonder what to do next while staring at their swollen LiPo battery, it is vital to note that swollen LiPo is dangerous. There are so many reported cases of swollen batteries starting a fire.

However, not all swollen batteries will explode, but it still does not mean that people can make use of them.

Many people have asked how to fix swollen LiPo batteries; the answer remains it cannot be fixed but rather be disposed of as quickly as possible. LiPO Batteries Maintain and LIPO Battery Safety Tips can help you use lithium polymer battery more safely.

How to prevent a lipo battery from swelling

Many people have asked how to fix swollen LiPo batteries; the answer remains it cannot be fixed but rather be disposed of as quickly as possible. Another question pertaining to swollen LiPo batteries has to do with the cause of the batteries to swell up.

Basically, gas production in lithium-ion batteries is regular. It does not matter if you abuse your battery or not; the regular daily use of the said battery can produce gas via a process known as electrolyte decomposition.

This electrolyte decomposition happens rapidly if the battery is overcharged or there is overheating of the battery.

Swollen LiPo Battery Disposal

Generally, the first thing to do about swollen batteries from LiPo is to dispose of it carefully and quickly purchase a new one.

Swollen batteries can take place as a result of several reasons ranging from an overcharge or puncturing.

Furthermore, when individuals notice swollen batteries, it is highly safe to stop making use of it and throw it all away.

The LiPo batteries can be protectively disposed of with the traditional battery disposal service or possibly thrown in the bin so far they are discharged completely. However, there are other ways to dispose of the swollen LiPo battery such as;

· Check through the yellow pages to see if there is any local battery disposal service around as it is the easiest way to dispose of the battery

· There is also homemade battery disposal.

This entails draining the battery to 0V because lithium polymer batteries are secure if they do not carry any voltage. Next step is to take a bucket filled with sand and place the battery inside while outside.

Link either a led or small lamp to this battery and fully drain it as it is left connected for 24 hours. When the led stops glowing, one can cut off the connectors from the battery. The wires should be stripped as well as the black and red wires are joined to build a short circuit and stop any voltage build up. With the LiPo battery safely stabilized, one can safely place it in the common trash.

· Some people either shoot or nail their batteries. Though this is intriguing, it is not advisable.

All in all, any technique for disposing of the LiPo battery is safe so far it is carried out outside the home.

How to prevent a lipo battery from swelling

LiPo Battery Explosion

The lithium polymer batteries are likely the most dangerous aspects to be dealt with on a daily basis.

This has to do with its propensity to explode into little fireballs when maltreated basically, and due to the huge volume of power, they can drop out from the terminals.

LiPo battery explosions are simple to understand. The lithium ion in the LiPo hates being exposed to air.

All the explosions take place for a particular reason which centers around the cells in each pack getting punctured or somehow ruptured and exposing the innards to air.

The violent nature of the explosions will rely solely on the amount of electrical charge the battery actually has. Simply put, in a completely charged battery, its reactive elements are vulnerable to harsh chemical reactions whenever they are exposed to air.

So, when the battery is actually discharged, the same exact elements are kept in a decreased exothermic cocktail. Basically, overcharging is another way for the batteries to explode.

This overcharging takes place when an increased voltage is implemented all over the cells of a LiPo battery. A voltage higher than 4.2V will likely result in a chemical reaction that cannot be reversed.

This, in turn, will generate both gas and heat. The battery will then begin swelling, and the only next step is to explode. Also, overcharging can take place when a person tries to charge the battery faster than it can accept that particular charge.

Meanwhile, the best approach to protect the battery against issues of overcharging is to have a constant habit for charging that protects everyone from executing mistakes when charging the LiPo.

As for punctures, it could occur due to a serious crash or a general mishandling of the battery. The batteries will explode at once and probably chain the good cells during this process.

How to prevent a lipo battery from swelling

Best LiPo Battery Protection

There are battery producers like Dinogy that make battery packs with fiberglass protective layers on both sides of the battery. This helps to provide compelling protection from any form of an explosion caused by punctures.

However, it is vital to make use of LiPo compatible chargers for the LiPo batteries. This because the batteries demand special care and they charge by making use of a system known as CC/CV charging.

This basically stands for Constant Current/ Constant Voltage. The chargers will help to keep the charge rate or current constant till the battery attains its highest voltage which is 4.2v per cell.

With the LiPo compatible charger, the LiPo batteries are balanced to make sure every cell discharges exactly the same amount. It will help in the performance of the battery. It is also important for safety purposes.

How to prevent a lipo battery from swelling

Final Thoughts

In using LiPo batteries, it does not matter the likelihood of fire not occurring; every user must take safety precautions. Users should have a fire extinguisher around them. Though the extinguisher will not put off the fire, it will simply help to stop it from spreading.

LiPo batteries can as well be charged in fire-resistant containers although most users would rather purchase LiPo bags. LiPo batteries should never be left to charge without the user checking on them.

Akemi Iwaya has been part of the How-To Geek/LifeSavvy Media team since 2009. She has previously written under the pen name “Asian Angel” and was a Lifehacker intern before joining How-To Geek/LifeSavvy Media. She has been quoted as an authoritative source by ZDNet Worldwide. Read more.

How to prevent a lipo battery from swelling

Dealing with a lithium-ion battery that has gone bad and is swelling up is not a fun prospect, but what do you do if you are unable to properly dispose of it quickly? What is the best way to store it until you can get rid of it? Today’s SuperUser Q&A post has some helpful advice for a concerned reader.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

The Question

SuperUser reader A.Grandt wants to know how to safely store a defective (bulging) lithium-ion battery:

I have a defective lithium-ion battery, one that is bulging quite severely and is about 50 percent thicker in the middle than it is at the edges. While the battery still actually works, I have replaced it since it would no longer fit inside my mobile phone and was about to make the screen come loose.

I cannot safely dispose of it just yet, so my question is, is it safe to just leave it unused on a table until I can get around to disposing of it or would it be safer to keep it cool/frozen?

How do you safely store a defective (bulging) lithium-ion battery?

The Answer

SuperUser contributor Journeyman Geek has the answer for us:

How to prevent a lipo battery from swelling

I had this happen and had to store it until there was ample time to drop by a designated e-waste center that specifically accepted lithium-ion batteries. This is important! Throwing potentially inflammable materials in with regular trash is bad (only you can stop fires)!

There is likely no need to panic if it is just a week or two until you can properly dispose of it. You want to store it for as short a time as possible. For the most part, unless you stab it, an unused bloated battery ought to be reasonably safe.

On a practical note, you want to leave it somewhere cool and dry, so a refrigerator is not the best place. The refrigerator trick is used for dying batteries in some cases, but not dead ones.

I would suggest taping over the connectors to prevent accidental shorting and just leave it somewhere safe. Freezing a battery does not sound bad until you realize there will be a sudden change in temperature (potentially bad) and condensation (moisture) when you need to take it out.

It is also worth remembering that this happened over the course of weeks or even months before it became noticeable. There was some pressure on the screen and I had assumed it was an air bubble behind the screen protector. I noticed the bloating entirely by accident.

So, short of baking (inadvertently or otherwise), burning or stabbing your battery, or taking a few months to dispose of it, you probably do not need to massively baby the battery. Just do not charge it (and for once self-discharge is fine). A battery not in use is slightly less likely to spontaneously catch fire.

There are a few suggestions that I have seen online, like putting the battery in salty water (which sounds like a terrible idea, especially since lithium reacts violently with water and is a potential source of bloating anyway) or trying to discharge the battery (the energy flow could mean heat which could lead to a fire). The MSDS backs this up suggesting that the electrolyte reacts with water to form HF (which is nasty), the anode with H2, and many other scary things.

So leave it alone, keep an eye on it, avoid Viking funerals, and you should be fine.

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.