Why Is My Battery Pack Swollen and Is It Safe?

You may have either heard of or personally seen a swollen battery in a portable charger or smartphone. This article answers the following questions:

What causes this problem to happen?
Is it still safe to use the device?
How can I dispose of the battery safely?

Portable chargers and smartphones typically contain lithium-ion batteries. Some common causes of lithium-ion battery swelling are summarized in this article: https://www.dfrsolutions.com/blog/why-do-lithium-ion-batteries-swell

"Common causes of battery swelling include:

  1. Overcharge conditions which accelerate parasitic reactions between the electrodes and electrolyte, with release of heat and gases.
  2. Poor cell quality and design with low anode to cathode stoichiometric ratios, particulate contamination
  3. Mechanical damage to electrodes induced either during cell assembly or from the product application
  4. Excessive temperatures (Do not leave your cell phone inside your car)
  5. Deep discharge of cells"

From ifixit.com's guide:

"Lithium-ion batteries use a chemical reaction to generate power. As the battery ages, this chemical reaction no longer completes perfectly, which can result in the creation of gas (called outgassing), leading to a swollen battery."

ZMI battery packs have protections against battery overcharge and overdischarge. However, mechanical damage (i.e., dropping a battery pack) can potentially cause the battery to swell. Also, storing and operating the battery pack at high temperatures can cause a wide range of issues. In the summertime it is especially important to make sure not to leave your smartphone or battery pack in the car for long periods of time.

If you notice swelling of a battery, it is important to stop using the battery or the device containing the battery immediately and take steps to dispose of the battery properly.

To properly dispose of a swollen battery, make sure to place the battery on a non-flammable surface or inside a fire-proof container. Metal surfaces and sand work best. Do not throw the battery in the trash. Do not expose the battery to liquids and moisture. The battery should be disposed of at a recycling center that can handle e-waste. 

Here are a couple links to help you locate recycling centers that handle e-waste.



If you are unsure if your battery is swollen or not, or if you have other questions regarding the safety of our products, please contact us for help.

battery safety swelling swollen battery

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