Are Loose Lithium-ion Battery Cells Harmful?

The question follows warnings from the U.S. Consumer Product Safety Commission to avoid buying or using loose 18650 lithium-ion battery cells. The CPSC informs us that these cells are manufactured as industrial components of battery packs and not (at least by the original manufacturer) should be sold to consumers as individual Li-ion cells. However, the Commission also reports that these cells are often disconnected, repackaged and sold on the internet as new consumer batteries. Are these loose lithium-ion battery cells actually dangerous?

Given that individual Li-Ion cells make a big difference in small consumer products, especially power tools, steam products, and more, many of us may want to educate ourselves enough to make informed decisions.

Proper protection

Without proper protection, Li-ion batteries are prone to all kinds of fiery malfunctions. We’ve seen everything from battery immersion warnings to hoverboards exploding.

However, these protective measures are usually integrated into battery pack designs at tool manufacturers. Li-ion batteries have electronic and physical controls that cool the cells inside. This includes circuitry that communicates with tools and / or chargers to prevent overcharging, overdischarging, overheating, and other potential problems.

The problem with individual Li-ion battery cells is that when they are removed from a battery pack, they do not have any of these protections. This may increase the risk of your battery malfunctioning. It also opens up more opportunities for personal injury.

Publisher’s Note: At this point there is also a similar argument for avoiding replacement batteries for the aftermarket. While opinions differ on this issue, it is clear that you have no idea what protections third-party vendors are putting into their packages. They also don’t know what to take out to save manufacturing costs.

Let’s talk about Thermal Runaway

Individual Li-ion cells

Are loose lithium-ion battery cells dangerous? The simplest answer is: possibly yes. Without proper protection, individual Li-ion cells (loose cells) can pose a significant risk to consumers. You can overheat quickly under certain circumstances. This can occur in the event of improper handling, transport, storage or charging. Without proper thermal management, overheating and short circuits can occur when powering small devices such as flashlights.

Risk of short circuit

Because of the way these batteries work, loose lithium-ion battery cells present a particular hazard. The exposed positive and negative metal terminals have a higher potential risk than NiMH or alkaline cells. Short the terminals and they create a rather sudden and violent discharge.

This can happen if they come across metal objects like keys or change in your pocket.

After the short circuit, these individual lithium-ion cells can overheat, which leads to thermal runaway. This occurs when the cell’s internal materials ignite and the cell forcibly expels its burning innards. This leads to fire, explosions, and serious or worse injuries.

Do you think we’re exaggerating? Incidentally, the preference of the loose cell for seemingly spontaneous combustion is known. In fact, it has already led the Internal Civil Aviation Organization, US DOT, FAA, and IATA to label certain lithium-ion batteries as Class 9 HazMat.

Thermal runaway can also occur in loose cells when placed in a charger that allows charging beyond the cell’s specifications. As more and more smaller consumer products use loose cells for power, this scenario becomes more common. It is also difficult to determine whether a third party manufacturer is adequately protecting against these conditions.

What can be done

The CPSC is working with e-commerce sites, including eBay, to remove listings that sell bulk Li-ion cells. In our view, informed and responsible people can make their own decisions about how to power their small devices.

However, should you decide to take the risk of potentially dangerous loose lithium-ion battery cells, there are a few steps you can take to minimize this risk:

  • If you are traveling with loose cells, keep them in a suitcase. Never let them wander freely in a pocket where they can come in contact with keys or change.
  • Do not charge loose cells unattended or overnight
  • Always keep the batteries dry
  • Do not use or place batteries near fire or in temperatures above 70 ° C. It is best that your batteries avoid heat and direct sunlight.
  • Look out for deformities, rust, changes in color, damage to the packaging or battery leakage. Stop using it immediately if you experience any of these issues.
  • Make sure that the maximum continuous discharge rate of your battery is not exceeded. Check the specifications of your model for this information.

With that said, the CPSC would appreciate your reporting any lithium ion battery issues to them by clicking here. You can also learn more about high energy battery safety by visiting this link.

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