According to the US Consumer Product Safety Commission (CPSC), thousands of thousands of incidents related to lithium battery fires are reported every year. Though lithium batteries are now a key component of our routine life, as they power solar backup systems, laptops, digital cameras, mobile devices, off-grid setups, and electric cars, users are worried about them catching fire.
People are even concerned about, "Can lithium batteries catch fire when not in use?". Are you one of them? You will get an answer to your query in this guide. Reliable performance, longer lifespans, and higher energy density make these batteries more popular, but they are not completely risk-free.
Though it is rare, yes, lithium batteries can pose fire risks under specific conditions, even when they are not in use. Different factors (such as manufacturing defects, improper storage, physical damage, and overcharging) play their part in the occurrence of fire incidents. We will discuss them later in this guide.
What It Means for a Battery to Be "Not in Use"?
When we say a lithium battery is not in use, it means it is not undergoing the charging process, not connected to any load, or not actively powering any device. Simply put, it is in an idle state. If this is the case, your battery is said to be in storage mode. It can be placed as a backup waiting to be used actively, during the off-season, or sitting in your RV.
When lithium batteries are not in use, it does not mean that they are completely dormant. These batteries naturally lose a small percentage of their total stored power over time. It is a slow process and is called self-discharge. This process occurs due to the chemical reactions within the batteries. Self-discharge is completely normal for lithium batteries and all other rechargeable batteries.
The self-discharge process indicates that lithium batteries are never fully inactive, but it doesn't contribute to fires. Since the internal chemistry of these batteries is always at work, proper storage and safe handling are crucial, even when they are not in use.
Do Lithium Batteries Pose a Fire Risk When Not in Use?
You may have heard of a couple of myths related to lithium battery fires. For example, people usually assume that these batteries won't catch fire if stored away and are unplugged. Well, this is not the reality. It is true that the risk of catching fire is much lower when a lithium battery is unplugged, but it is not zero, and can never be taken for granted.
The primary reason behind lithium batteries catching fire is a process called thermal runaway. It happens when a chemical reaction triggers inside the battery due to exposure to extreme heat, manufacturing defects, or internal damage. As a result, the battery cells are overheated uncontrollably (when the temperature exceeds 150 degrees Celsius), and they release energy much faster than it can be used.
In worst cases, thermal runaway leads to safety issues, such as explosion, fire, and smoke. This process can occur when your battery is in use or is connected to the charger. At the same time, batteries remain prone to thermal runaway even when they sit idle in a storage place. However, it may happen only if the battery is compromised in any way.
According to the National Fire Protection Association (NFPA), over 800 lithium-ion battery fire-related incidents have been reported in New York City since 2022. These incidents caused over 400 injuries and 30 deaths.
The reality is that unused lithium batteries can catch fire, but the chances are low. If you want to keep the risk of fire under control, pay close attention to storing your battery in a safe place, avoiding damage, and proper handling.
Causes of Lithium Battery Fires During Storage
Generally, lithium batteries are safe to use, but they can pose fire risks under particular conditions. These risks are mainly divided into three categories, as given below. Let's explore them one by one.
1. Internal Factors
According to the ABC Institute, internal faults lead to 25% lithium-ion batteries catching fire. When it comes to internal factors, two things come into play, i.e, manufacturing defects and internal short circuits.
Impurities inside the battery cells and poor-quality separators are the prominent manufacturing defects that cause internal short circuits. When internal short-circuiting happens, it may produce heat and initiate thermal runaway, even if your lithium battery is connected to the charger or load.
For example, a manufacturer of electric vehicles reported around 10 cases related to lithium battery fires in 2019. 70% of these cases were due to internal short circuits that occurred due to defective separators. It clearly highlights how important quality control is while manufacturing batteries.
2. External Factors
They cover both physical damage and exposure to extreme heat. Physical damage can be caused by crushing, puncturing, or dropping the battery during transportation. It may lead to weakening the protective layers. Therefore, transporting lithium batteries in protective cases is always recommended.
At the same time, extremely cold or extremely hot temperatures are equally dangerous to lithium batteries. Extreme temperatures accelerate chemical degradation. Moreover, moisture causes corrosion on internal components. They both may lead to fire risks.
When the temperature is around 130 degrees Celsius, it may decompose a common lithium battery. This is why you should avoid exposing your battery to direct sunlight or other heat sources, as extreme heat can destabilize the electrolyte.
3. Improper Storage
Proper storage plays a key role in defining the lifespan of lithium batteries. Don't stack batteries too tightly to avoid the buildup of physical stress and pressure. Moreover, store your lithium batteries away from incompatible materials (such as metal objects and flammable items), as they may lead to short circuits, which increases the chance of batteries catching fire.
The most recent fire incident was reported in January 2025, when the batteries in the world's largest battery facility - Vistra Energy Storage Facility - caught fire due to improper storage in California.
Safety Tips for Storing and Handling Lithium Batteries
If lithium batteries are treated properly, they are completely safe to store and use. At the same time, poor storage and mishandling may lead to various safety concerns. A few safety and handling tips are listed below. Following the given tips will help you ensure both longevity and enhanced safety.
1. Best Storage Practices
Always store or keep your batteries away from heat sources, such as heaters or direct sunlight. A cool, dry place is a perfect spot to store your lithium batteries. At the same time, avoid storing your batteries in humid or damp environments, as they can cause corrosion. Find more storage guidelines here.
Modern equipment has been introduced to ensure safe storage, such as fireproof battery bags and protective cases. They prevent batteries from short circuits, punctures, and accidental damage.
2. Charging Instructions
Using random chargers to recharge your lithium batteries is not a good practice. Always use a manufacturer-approved battery charger designed specifically to meet your battery needs.
Once the battery is fully charged, unplug the charger to avoid overcharging issues. Avoid charging your batteries in extremely cold or extremely hot conditions. Similarly, don't charge your lithium batteries near flammable material to avoid any inconvenience.
3. Safe Disposal and Recycling
If a lithium battery has completely failed or is damaged and is no longer in use, don't throw it in the household trash, as it may spark and catch fire. Instead, wrap each used battery in a non-conductive material and dispose of it properly or recycle it through local collection programs or certified recycling centers.
4. A Specific Advice
Always make a battery purchase from trusted and certified brands like Renogy that offer lithium batteries with built-in safety features, such as BMS protection and self-heating. Pro-Renogy 12V 100Ah Smart LiFePO4 Battery is a prime example of such batteries.
The built-in safety features in Renogy batteries safeguard them from various issues, such as overheating, over-discharging, and overcharging. Therefore, these batteries are a reliable choice for RV, off-grid, and solar applications.
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What to Do If a Battery Shows Warning Signs?
Though lithium batteries fail rarely, it is important to act fast if you notice any warning signs. The potential warning signs are as follows.
- A chemical-like, foul, sharp smell
- Unusual heat or melting plastic
- Popping or hissing sounds
- Sparks or smoke
- Bulging or swelling on the battery case
If you notice any of the above-mentioned signs, take immediate action, as listed below.
- Ensure personal safety by evacuating the affected area immediately.
- Don't use water to stop the battery fire. Instead, you can use a Class D fire extinguisher for small lithium batteries. You can also use dirt or sand to stop flames.
- Call emergency services for professional and timely assistance.
Once the incident happens, never repair or reuse the damaged battery. Instead, place it in a non-conductive container and take it to a certified recycling or waste facility for safe and proper disposal.
Frequently Asked Questions
Can a lithium battery catch fire when not being charged?
Yes, your lithium batteries can be at risk, even when they are not being charged. However, it is rare, as mentioned in the discussion above. The risk of catching fire usually increases with improper storage, internal defects, or damage. Proper storage and safe handling greatly reduce the chances of fire or thermal runaway.
Is it safe to keep a lithium battery in the house?
If you keep your lithium battery away from flammable materials and direct sunlight, and store it in a dry, cool place, it is absolutely safe to keep indoors. If you want to add extra protection to avoid any sort of inconvenience, use battery safety bags or fireproof storage containers.
Should you remove lithium batteries when not in use?
Yes, it is a good practice to remove your battery from all devices if it is not in use. Doing this helps you reduce the chance of the battery catching fire or undergoing thermal runaway. Make sure the battery is partially charged before you store it in a cool, dry place. It will preserve its health and maximize safety.
How long can a lithium battery sit unused?
Well, it all depends on how they are stored. If you have stored your lithium battery properly, it can sit idle or unused for a couple of months to one year. Remember, lithium batteries undergo self-discharge naturally; therefore, recharging and periodic checks are recommended.
Final Thoughts
Lithium batteries are reliable and efficient, but they need safe storage and careful handling like all other energy devices. It is true that lithium batteries can catch fire, but it is rare. In most cases, fires are preventable. If you want to get the maximum out of your lithium batteries, ensure you use manufacturer-approved chargers, store them in a cool, dry place, and always respond quickly to warning signs.
Renogy prioritizes safety and offers lithium batteries with modern Battery Management Systems (BMS) protection to prevent issues like fire risks, overheating, and overcharging. Whether you want to power an off-grid system, an RV, or a solar setup, you can always count on Renogy batteries, as they deliver both safety and performance.
