A summer caution regarding your 18650 Lithium Ion-Battery

Lithium-ion batteries have become an indispensable part of our modern lives. From powering our smartphones to electric vehicles (i.e Tesla Model S & Model X), the compact and efficient 18650 lithium-ion battery is a popular choice because of its high energy density and rechargeable capabilities- in which OraliQ uses for its PBM Lights as a power source. However, like any power source, these batteries require careful handling, especially during hot summer months when the risk of overheating and potential hazards increases. Here we will discuss the safety issues associated with 18650 batteries and essential tips to prevent overheating dangers during scorching summers. 


The “18650” battery is a rechargeable lithium-ion battery named after its physical dimension. It is 18mm in diameter and 65mm in length. The “0” number indicates that it’s a cylindrical cell. Cylindrical cells incorporate a similar design that has been standard for the popular AA battery cells. It is the “workhorse” of the lithium-ion battery industry. 

Lithium-Ion Battery Hazards: 

Lithium-ion battery fire hazards are associated with the high energy densities couples with the flammable organic electrolyte such as ethylene carbonate or diethyl carbonate. This creates a challenge for use, storage, and handling. Studies have shown that physical damage, electrical abuse such as short circuits and overcharging, and exposures to elevated temperatures can cause a thermal runaway (this refers to rapid self-heating). Batteries may explode, burn, or cause a fire if misused or mishandled. 

  1. Overheating and Thermal Runaway: One of the primary safety concerns with 18650 batteries is overheating, which can lead to a phenomenon called "thermal runaway”. 
  1. Short-Circuiting: Short-circuiting can happen if the positive and negative terminals of the battery come into direct contact, creating a surge of energy that may lead to overheating and safety hazards.
  1. Overcharging and Overdischarging: Charging 18650 batteries beyond their capacity or discharging them to extremely low levels can cause stress on the battery and compromise its safety and overall lifespan.

Do and Don’ts of Safety Issues with 18650 Lithium-Ion Battery 


  1. 1. Do: Check for Damage

Regularly inspect your 18650 batteries for any signs of physical damage such as dents, scratches, or leaks. If your battery's wrap is damaged or peeling, replace it immediately.

  1. 2. Do: Store Batteries Properly

Store your 18650 batteries in a cool, dry place away from direct sunlight, flammable materials, and metal objects that could cause short-circuiting. Avoid keeping batteries in your car, purse, or pocket during hot summer days. If the battery is not being used, it must be stored in a protective box. 

  1. Do: Allow Cooling of Battery or In Between Operations of PBM Lights 


  1. 1. Don't: Expose Batteries to Extreme Temperatures or Liquids

Extreme temperatures, both hot and cold, can negatively impact battery performance and safety. 

  1. 2. Don't: Overcharge or Over-discharge

Always charge your 18650 batteries before they are completely depleted and avoid overcharging them. Remove batteries from chargers once they reach their full capacity.

  1. 3. Don’t: Ignore when the battery emits an unusual smell, feels hot, changes color or shape, or appears in an abnormal way. 

Safety Tips for Handling 18650 Batteries Especially During Hot Summers

  1. Optimal Charging: Charge your batteries in a cool and well-ventilated area. Avoid leaving them on charge unattended for a long period of time. 
  1. Limit Direct Sunlight Exposure: When using devices powered by 18650 batteries, try to avoid direct sunlight exposure, as this can raise the battery's temperature significantly.
  1. Allow Cooling Periods: If your device becomes noticeably warm during use, power it off and let it cool down before continuing to use it.


Source: “Lithium-Ion Battery Safety”, University of Washington, Environmental Health & Safety. Pg. 1-6 

1 comment

  • Chong Altenburg

    I had a problem with PBM Light+; it doesn’t hold power for less than 5 minutes and I requested return but I realized it’s a problem with a battery, not a PBM Light because it works fine with another battery. How can I exchange a non-working battery?

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