March 12, 2024
What to do with swollen lithium battery safely?
Until now, lithium batteries have been widely used in the market due to their high energy ratio and high security.
Although it does not have a higher level of security like polymer batteries, but because of its earlier development, so it is cheaper, and at the same time a lot of manufacturers are able to produce, which leads to unevenness, and the safety of lithium batteries sometimes can not be guaranteed, in addition to the fact that if used improperly.
In addition, if used improperly or limited production level, there are still some safety risks, such as swollen lithium battery.
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The basic structure analysis of lithium battery pack
The main material composition of lithium battery pack: anode and cathode materials, electrolyte, separator (isolation material) composition.
Cathode
From the perspective of battery weight composition, positive electrode material occupies a large proportion (generally 70%~80%), because the performance of positive electrode material directly affects the performance of lithium-ion battery, and its cost also directly determines the cost of battery.
Positive electrode material accounts for 30%~40% of the cost of lithium-ion battery, which also directly affects the energy density and performance of lithium-ion battery pack.
Anode
Negative electrode material is composed of material with lower potential relative to positive electrode, and has high specific capacity and better charge/discharge reversibility, so as to maintain good dimensional and mechanical stability (no serious deformation) in the process of embedded lithium.
Negative electrode materials mainly affect the efficiency of lithium battery packs, cycle performance, etc. The performance of negative electrode materials also directly affects the performance of lithium batteries, and negative electrode materials account for about 10~20% of the total cost of lithium batteries. The types of anode in lithium ion battery include carbon anode and non-carbon anode.
Electrolyte
Battery electrolyte plays the role of transporting charge between positive and negative electrodes (similar to the carrier in radio), and has high ionic conductivity, which generally should reach 1×10-3~2×10-2 S/cm.
It affects the energy density, wide temperature application, cycle life, power density, safety performance and other factors of lithium battery pack.
Separator
The lithium ion battery separator has a certain pore size and porosity to ensure low resistance and high ionic conductivity, good permeability to lithium ions, good wettability to the electrolyte and sufficient liquid absorption and moisturizing ability to maintain ionic conductivity, and at the same time, electronic insulation to ensure mechanical isolation of positive and negative electrodes.
In addition to sufficient mechanical properties such as puncture strength, tensile strength, and resistance to corrosivity of electrolyte and sufficient electrochemical stability. Power batteries have higher requirements for separator, usually using composite membranes.
Why is my lithium battery swollen?
There are three main reasons for swollen lithium battery:
Manufacturer production process problems
Many manufacturers in order to save costs, making the production environment is poor, the use of equipment to be eliminated equipment machines, etc., which makes the battery coating is not uniform, the electrolyte mixed with dust particles, etc..
These may make the lithium battery module in the user’s use of the phenomenon of bulging, and even greater danger.
User's daily use habits
The second lies in the user itself, if the user in the use of lithium battery products improper use, such as over-charging and over-discharging, or in the environment of the environment is extremely harsh environment, such as continuous use may also make the lithium battery bulging.
One of the reasons for overcharging and over-discharging of the bulging is as follows:
Overcharging
Overcharging will cause all the lithium atoms in the positive electrode material to run into the negative electrode material, resulting in the deformation and collapse of the originally full grid of the positive electrode, which is also a major reason for the decline in lithium battery power.
In this process, the negative electrode of lithium ions more and more, excessive accumulation of lithium atoms grow stump crystallization, making lithium batteries bulging.
- Over-discharge
During the first charge/discharge process of a liquid lithium ion battery, the electrode material and electrolyte react at the solid-liquid phase interface to form a passivation layer covering the surface of the electrode material.
The passivation layer can effectively prevent the passage of electrolyte molecules, but Li+ can be embedded and dislodged freely through the passivation layer, which has the characteristics of a solid electrolyte, so this passivation layer is called “solid electrolyte interface”, or SEI for short.
The SEI film has a protective effect on the negative electrode material, so that the structure of the material is not easy to collapse, and can increase the cycle life of the electrode material.The SEI film is not static, there will be a little change in the charging and discharging process, mainly part of the organic matter will be reversible changes.
After over-discharge of the battery, the SEI film will be reversibly broken, and the SEI that protects the negative electrode material will be destroyed and the negative electrode material will be collapsed, thus forming the bulging phenomenon.
These two factors will lead to the battery in the use of the process, the battery internal close to the short-circuit violent reaction, generating a large amount of heat, which in turn leads to the decomposition of the electrolyte gasification, the battery is bulging.
Long-term unused and improper storage
If any kind of product is not used for a long time, the original performance will basically decline, the battery is not used for a long time, and then also did not carry out a better preservation treatment. When it is not used for a long time exposed to the air, and full of electricity.
As the air is conductive to a certain extent, put too long is equivalent to the battery’s positive and negative poles in direct contact with a chronic short circuit, once the short circuit will heat, some electrolyte decomposition and even gasification, resulting in the occurrence of bulging.
Is a swollen lithium battery dangerous?
Yes, a swollen lithium battery is potentially very dangerous. The swelling is an indication of internal damage and gas buildup, which can lead to several hazardous situations:
- Risk of fire: The gases produced inside a swollen battery are highly flammable. If the battery casing ruptures, these gases can ignite, leading to a fire. This is particularly dangerous if the battery is in close proximity to other flammable materials.
- Risk of explosion: In extreme cases, the pressure from the gas buildup can cause the battery to explode. An explosion can scatter burning debris and toxic chemicals, posing a significant threat to both people and property.
- Toxic leakage: If the battery casing is compromised, the electrolyte – a corrosive and toxic substance – can leak out. This can cause skin irritation or more severe injuries if it comes into contact with the eyes or is ingested.
- Device damage: A swollen battery can exert pressure on the internal components of the device it is housed in, leading to physical damage. This can result in malfunction or complete failure of the device.
How to dispose of swollen lithium ion battery?
- Start recharging when about half of the battery power is used up, and only perform a complete discharge and full charge in very rare cases (for example, after several months to half a year, perform a complete discharge and charge once). Frequent full discharges and charges can easily lead to crystallization. This approach can greatly reduce crystallization and significantly slow down the swelling phenomenon.
- A swollen lithium battery can be discarded directly because its power capacity is already very low, and it has little power left after a short circuit.
- Lithium battery packs generally need to be recycled professionally to avoid pollution. If you can’t handle it, just throw it into a classified recycling bin.
These are the correct way to handle a swollen lithium battery pack.
Can a swollen lithium ion battery explode on its own?
Yes, a swollen lithium-ion battery can potentially explode on its own, especially if it is not handled properly. Here’s why:
- Gas pressure build-up: As the battery swells, the internal pressure increases due to the accumulation of gases. If this pressure exceeds the structural integrity of the battery casing, it can rupture, leading to an explosion.
- Thermal runaway: If a swollen battery is exposed to heat, it can undergo a thermal runaway – a self-sustaining reaction that generates more heat, causing further decomposition of the electrolyte and more gas production. This can eventually lead to an explosion.
- Short circuit: Internal damage caused by swelling can lead to a short circuit within the battery. A short circuit generates heat, which can ignite the flammable gases inside, causing an explosion.
- External factors: External pressure, such as accidentally crushing the battery or dropping it, can trigger an explosion. Even leaving a swollen battery in a hot environment, like inside a car on a sunny day, can cause it to explode.
Can you throw away swollen lithium batteries?
No, you should never throw away swollen lithium batteries in regular trash bins. The correct way to dispose of a swollen battery is to take it to a certified recycling or electronic waste disposal facility. These facilities are equipped to safely handle and process lithium batteries.
Is it safe to use a swollen lithium battery?
No, it is not safe to use a swollen lithium battery. Continuing to use a swollen battery can lead to serious risks.
The safest course of action is to stop using the swollen battery immediately and replace it with a new one. The swollen battery should be disposed of following the guidelines provided earlier.
Can a swollen battery shrink?
No, a swollen battery cannot shrink back to its original size. The swelling is caused by the buildup of gases inside the battery due to internal damage, and this damage is irreversible. It is a sign that it is no longer safe to use and should be disposed of responsibly.
How can you prevent a lithium battery from swelling?
Preventing lithium battery swelling involves following best practices for battery care and usage. Here are some key tips:
- Avoid overcharging
Never leave your devices plugged in for extended periods, especially overnight. Use chargers with built-in overcharge protection to stop the charging process once the battery is full.
- Keep batteries cool
Avoid exposing your devices to high temperatures, such as direct sunlight or leaving them in a hot car. High temperatures can accelerate chemical reactions inside the battery, leading to swelling.
- Use quality chargers
Always use chargers and cables that are recommended by the device manufacturer. Cheap or counterfeit chargers can deliver inconsistent power, leading to overheating and battery damage.
- Regularly monitor battery health
Some devices allow you to check the battery’s health through software. Regularly monitoring the battery’s condition can help you catch issues before they lead to swelling.
- Avoid deep discharges
Lithium batteries have a limited number of charge cycles. Frequently allowing the battery to fully discharge can shorten its lifespan and increase the likelihood of swelling. Aim to recharge your battery when it reaches around 20-30% capacity.
- Store batteries properly
If you need to store a battery for an extended period, keep it in a cool, dry place at about 50% charge. Avoid storing fully charged or fully discharged batteries for long periods.
- Replace old batteries
As batteries age, they become more prone to issues like swelling. Regularly replace old batteries with new ones to reduce the risk of swelling.
How do you safely remove a swollen lithium battery from a device?
Removing a swollen lithium battery from a device requires caution to avoid further damage or injury. Follow these steps for safe removal:
- Turn off the device: Before attempting to remove the battery, power down the device completely. Disconnect it from any power sources to reduce the risk of electrical shock or short circuits.
- Wear protective gear: Wear gloves and safety glasses to protect yourself from any potential leaks or sharp edges on the swollen battery.
- Use non-metallic tools: Use plastic or other non-metallic tools to pry the battery out of the device. Metal tools can cause a short circuit if they come into contact with the battery terminals.
- Handle with care: Gently remove the battery without applying excessive force. If the battery is stuck, do not attempt to puncture or bend it, as this could cause a fire or explosion.
- Place in a fireproof container: Once the battery is removed, place it in a fireproof container, such as a metal or ceramic container, to safely transport it for disposal.
- Dispose of properly: Follow the guidelines provided earlier for the safe disposal of swollen lithium batteries. Do not leave the battery lying around or attempt to dispose of it in regular trash.
If you are unsure or uncomfortable removing the battery yourself, it is advisable to take the device to a professional repair service. They have the tools and experience to safely handle and dispose of swollen batteries.
Conclusion
Swollen lithium batteries are a serious lithium battery safety concern that should not be taken lightly. Understanding the structure of lithium batteries, the causes of swelling, and the proper steps for handling and disposing of swollen batteries can prevent accidents and ensure both personal and environmental safety.
By following best practices for battery care and being vigilant about the signs of swelling, users can enjoy the benefits of lithium batteries while minimizing risks.
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Nancy
Nancy has worked hands-on with battery swap infrastructure for electric two- and three-wheelers since 2021, including deployment projects in South Asia. She regularly consults on EV fleet electrification and has contributed technical specifications to multiple swapping station manufacturers. Her market analysis is grounded in direct collaboration with importers, dealers, and RMV registration data.
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