How to handle a swollen lithium battery

Why do lithium batteries swell?

Lithium batteries swell because gas builds up inside the cell. The gas comes from electrolyte breaking down, usually as a result of overcharging, overheating, age, physical damage, internal defects, or deep discharge. The cell’s casing, especially in soft pouch cells, expands as the pressure rises, and the battery may look puffy, bulging, or may push apart the device around it. Swelling is a sign that the cell’s internal chemistry has been compromised. The battery may still seem to work, but its internal structure may be damaged, and the risk of short circuit or thermal runaway is higher.

A swollen battery should not be treated as a simple reduction in capacity. It should be treated as a safety problem and removed from service. Some swelling is caused by manufacturing defects, but heat is the most common trigger. Leaving a phone on a car dashboard, charging a laptop on a bed, or storing batteries in a hot warehouse all accelerate the breakdown. Understanding the cause helps you decide whether the problem is isolated or whether other batteries in the same environment are also at risk.

What should you do first if you find a swollen battery?

Stop using and charging the battery immediately. If it is in a device, power the device off, unplug it from any charger, and move it away from combustible materials if you can do so without squeezing or bending the battery. Do not try to flatten, puncture, or open it, because that can trigger a short circuit and fire. Keep people and pets away, and avoid leaving the device in a car, on a bed or sofa, or near a window in the sun. If the battery is hot, smoking, or hissing, leave the area and call 911 rather than moving it.

Once it is stable and cool, follow the isolation steps below. Do not keep using a device just because it still turns on. If the battery is inside a device that is plugged in, unplug it using a dry hand and by gripping the plug, not the cord, only if the area is clear of smoke. Avoid using water on a smoldering device unless guided by emergency responders. Call the local non-emergency number or the manufacturer if you are uncertain, and call 911 if there is any fire or strong chemical smell.

• Power off the device and disconnect the charger.
• Do not press, bend, puncture, or open the battery.
• Move it away from combustibles only if it is safe to do so.
• If it is hot or smoking, evacuate and call 911.

How do you isolate a swollen battery safely?

Isolate a swollen battery in a non-combustible container, away from other batteries and anything flammable. A ceramic or metal container with a lid can be used for short-term holding, and a layer of sand or another non-combustible, non-conductive filler such as vermiculite helps absorb heat and keep the battery from touching other surfaces. Do not seal the container so tightly that gas has no way out. Place the container in a cool, ventilated area, ideally outdoors or in a garage or storage room with nothing combustible nearby, and away from living and working spaces.

Do not store the battery in a closed vehicle or an attic. Label the container so others know not to touch it, and check it occasionally from a distance for heat, smoke, or odor. Keep a log of where swollen batteries are stored and when you placed them there. Check them regularly and do not leave them for long. A swollen battery that sits for months in a closet is a hazard waiting for a bad day. Arrange pickup or shipment promptly, because the situation only becomes riskier with time.

Should you tape the terminals of a swollen battery?

Yes, if you can do it without touching or stressing the swollen cell. Covering exposed terminals with non-conductive tape reduces the chance of a short circuit while the battery waits for pickup. If the battery is in a device and you cannot reach the terminals, leave it in the device and isolate the whole device instead of trying to remove it. Do not pull or pry at a swollen pouch cell. The layers inside may already be deformed, and a small cut or bend can start a short.

If you are unsure whether removal is safe, leave the battery in place and ask for guidance. A swollen battery inside a laptop, phone, or tool is often better shipped inside the device to a recycler that can handle it. Wear gloves and eye protection if there is any chance of leakage, and wash your hands after handling. If electrolyte contacts skin, rinse with water for several minutes and seek medical advice if irritation develops. Keep the battery away from sources of water, since moisture can corrode contacts and complicate packaging. Treat the whole event as a hazardous materials handling task.

Can a swollen battery be shipped or mailed?

A swollen battery is generally treated as a damaged or defective battery for shipping. Under DOT rules, damaged or defective lithium batteries cannot move under the simple small-package exceptions, and they should not be shipped by air. They need packaging designed to contain heat and prevent short circuits, and a carrier arrangement that allows them. Do not drop a swollen battery in a mailbox or at a parcel counter. Tell us what you have, the chemistry if you know it, the size, and how many units, and we’ll quote options for pickup or prepaid shipping with the right packaging.

Handling it correctly protects the carrier’s employees and everyone else in the supply chain. Because swollen batteries can deteriorate during transport, the packaging should hold the battery in place without pressing on it, with non-conductive filler around it. Recyclers often supply a container for this purpose. Follow their instructions exactly, and do not combine swollen batteries with healthy ones in the same box. Mark the box as containing damaged batteries as instructed.

What does DDR mean for lithium batteries?

DDR stands for damaged, defective, or recalled. It is a category used in lithium battery shipping and recycling for batteries that have been physically damaged, show signs of a defect such as swelling or leakage, or are subject to a manufacturer recall for safety reasons. These batteries carry a higher chance of overheating or fire. Recyclers treat DDR batteries differently from ordinary used batteries. They require more robust packaging, individual protection or non-conductive filler, and in many cases a higher handling cost.

Properly identifying a battery as DDR when you request a quote is important, because under-declaring the condition can create danger in transit and can lead to rejection at the facility. When in doubt, call it out. A recall notice or a known manufacturer defect changes the treatment as well. If your battery is part of a recall, contact the manufacturer or check the Consumer Product Safety Commission’s listings for instructions, and still arrange safe recycling afterward. Recalled batteries may qualify for replacement or reimbursement, so keep records and photos of the battery before it is shipped.

How can you prevent batteries from swelling?

You can reduce the chance of swelling by using the correct charger, avoiding heat and direct sun, and not leaving devices charging for extended periods. Do not use batteries that have been dropped, crushed, or exposed to water, and do not leave them fully depleted for months. Replace batteries that show reduced runtime together with other signs of aging. In a business setting, build inspection into routine maintenance. Check fleet devices, tools, and backup power systems for bulging, heat, and odd smells, and pull suspect batteries out of service immediately.

Keep a spare-battery program so that staff do not feel pressure to use a questionable pack. An early removal costs far less than a fire. For businesses, a written procedure should say who is authorized to handle swollen batteries, where the isolation container is located, and how to request pickup. Include the procedure in new-hire training for maintenance and fleet staff. Having an isolation kit with gloves, a lidded non-combustible container, filler, and tape ready makes it easy to respond correctly.