While electronic manufacturers have stretched the boundaries of what our devices can do on a single charge, you may still turn to a portable power bank or external battery for extra juice.

Portable power banks are great for keeping your phone or laptop powered up, but they wear down like other rechargeable batteries and are susceptible to failure. If you have a portable battery, it's unlikely that it will malfunction in as extreme of fashion as some of the high-profile cases seen in the news

However, you may wonder why there are TSA battery rules or why certain batteries have to be recalled due to malfunction.

Keep reading to learn more about lithium-ion battery safety and what you can do to keep your portable power banks in good shape.

How Portable Power Banks Work

Most portable power banks use lithium-ion batteries to hold a charge and then pass power on to your devices that need a boost. Like other rechargeable batteries, lithium-ion batteries work using a chemical transfer to generate electricity.

Unlike single-use batteries (AA, AAA, C and D), lithium-ion batteries can reverse the charge and discharge process. 

According to the Office of Energy Efficiency & Renewable Energy, lithium-ion batteries can power our devices by transferring positively charged lithium ions from the anode to the cathode, generating electrons that power the device. 

The process is reversed when the battery is plugged into an outlet and the lithium ions are sent back to the cathode.

While rechargeable batteries don't last forever, they can last much longer, charging hundreds, if not thousands, of times before they are no longer usable. Portable power banks have a port that sends a charge to the device you connect to it. 

Power Bank Safety: How Do Batteries Catch Fire?

Defective Batteries: The Reality of the Electrical Age

While most rechargeable batteries found in external battery packs will never show a sign of malfunction, it's smart to know where battery defects come from and signs that your power bank or device may have a defective battery.

Power bank defects can occur from a variety of places. Poor manufacturing and metal impurities in the battery are common threads you see throughout the recalled batteries. In some instances, the electronics in the device, like small controller circuits, that regulate the intake of power are faulty and cause the battery to overcharge or get too hot.

Fires can start from batteries due to a chemical reaction called "thermal runaway." Thermal runaway is when your battery creates more heat than it's able to dissipate into its surroundings. The rising temperatures can cause an explosion or fire as the heat consumes the materials making up the battery. 

Other times, external forces may cause the battery to malfunction, like blunt force (dropping the battery) or the temperature/humidity of the area around the battery.

Your device or external battery pack may be faulty if the battery shows these signs:

  • Bulging/cracking
  • Hissing
  • Leaking
  • Bad odor
  • Rising in temperature
  • Smoking before or during use

Power Bank Safety: Steps Towards Safety

If you are using an external battery and see any of these signs, it's key that you stop using it immediately. Move the device away from yourself and any other flammable materials until it appears safe to handle again. Contact your local battery recycling center to see how you should dispose of it.

If you want to keep your external battery pack in its best shape, here are a few tips to help you make the most of your portable power.

  • Purchase portable battery packs from reputable brands, known for manufacturing high-quality power banks. Sticking with reputable brands can help you avoid hazardous malfunctions as they will have more stringent testing and safety precautions. Off-brand or discount battery packs may seem like a good idea due to the price tag but may lack the quality control or engineering of more expensive options.
  • Don't expose an external battery pack to intense heat, cold or humidity. Treat your portable power bank like you would your phone or laptop: avoid exposure to extreme elements. Temperature variance can affect the chemical components of a battery and put it at risk for a higher likelihood of malfunction.
  • Don't charge any devices through the battery while it's charging unless it has pass-through capability. Always follow the manufacturer's instructions for charging and use. Use the standard cable and wall adapter or recommended wall adapter voltage for charging to avoid overcharge.
  • Don't purchase an external battery with over 300 watt-hours. The Transportation Security Administration limits the size of batteries to one 300 watt-hour battery or two 160 watt-hour batteries while traveling on an airplane. Since portability is one of the main functions of a portable battery, it's smart to keep it within TSA limits to avoid restrictions while traveling.

TSA Battery Rules and Airline Battery Restrictions

If you've traveled on a plane in the past three to four years, you may wonder why there are restrictions on battery packs like the watt-hour limit. One of the biggest reasons is the fire hazard that large external batteries present. 

One of the first restrictions you will see is that all "smart luggage" or luggage with battery packs must have removable batteries. Since checked luggage is carried in the plane's cargo area, a battery could catch fire without anyone present to alert the crew of the danger.

Any external batteries you have must be under the 300-watt-hour limit and in your carry-on luggage. Don't purchase luggage with built-in batteries as they are strictly prohibited from flying. 

Stay Smart with Your Electrical Safety

Electrical hazards are an unfortunate reality. Learn more about how you can prevent these potential dangers at home, outside or on the go with our electrical safety content.