Power banks are among the most useful accessories for smartphones and other electronic devices and become especially important when traveling or in places with limited access to electricity. However, these devices have a limited lifespan and the lithium-ion batteries used in them degrade over time and with repeated use.
Battery wear or damage can turn a power bank from a useful device into a safety hazard. For this reason, being aware of signs of battery failure and stopping use of a defective power bank is very important.
1. Swelling or deformation of the case
Swelling of a power bank is one of the clearest signs of battery failure and if observed the device should be taken out of service immediately. If the power bank no longer sits properly on a flat surface or there are bulges and cracks in its casing, it should not be connected to power or used to charge other devices.
Swelling is usually caused by gas buildup in the lithium-ion battery cells. Aging of the battery, exposure to very high or low temperatures, and improper charging are among the factors that can contribute to this condition.
Continued use of a swollen battery can increase the risk of fire and in certain circumstances even lead to an explosion. Therefore, a swollen battery should not be subjected to pressure, punctured, or reconnected to a device for reuse.
2. Excessive heating
Moderate warming of a power bank while charging a phone or recharging itself, especially when using fast-charging technologies, can be normal. However, if the power bank’s temperature rises to the point that it is difficult to hold, it should be considered a serious warning sign.
Abnormal heating can result from increased internal resistance of the battery or faults in protection and temperature control systems. Excessive heat can also damage the cable and the charging port of the connected device.
If the power bank becomes unusually hot during use or charging, it is better to disconnect it from the power source and not use it until it has been inspected or replaced.
3. Rapid discharge
If a power bank that is fully charged loses a large portion of its capacity in a short time, its battery has likely reached the end of its useful life.
Lithium-ion cells lose their ability to store and deliver stable energy over time and with repeated use. As a result, the actual capacity of the power bank decreases and its runtime becomes shorter.
A sharp drop in capacity does not necessarily mean the power bank is about to catch fire, but it can indicate battery wear or a problem in the device’s circuitry. For this reason, if the capacity loss is accompanied by overheating, sudden shutdowns, or other unusual signs, it is better to stop using the power bank.
4. Physical damage or unusual odor
Frequent drops, heavy impacts, or the power bank being subjected to pressure can damage the battery cells and other internal components. For this reason, large cracks, significant dents, or deformation of the casing-especially after a severe impact-should not be ignored.
Long-term exposure of a power bank to very hot environments, such as inside a parked car in direct sunlight, can also damage the battery.
A burning smell or an unusual chemical odor is a more serious warning and may indicate internal damage or leakage of battery chemicals. In such cases, the device should not be reconnected to power for testing.
How to dispose of a defective power bank?
If a power bank is swollen, damaged, or has a serious defect, it should not be thrown in household trash or regular recycling bins. Damaged lithium-ion batteries can pose a fire risk and therefore must be disposed of properly.
The best option is to deliver the damaged power bank to collection centers or battery and electronic waste recycling facilities that accept lithium-ion batteries. Of course, the disposal method for these batteries may vary by region and should be done in accordance with local guidelines.
In summary, swelling or deformation, abnormal heating, sharp reduction in runtime, and physical damage or unusual odor are four important signs that may indicate a problem with a power bank. If these signs are observed, continuing to use the device is not worth risking the safety of the user and electronic equipment.