18650 cells are cylindrical lithium-ion rechargeable batteries, measuring 18mm in diameter and 65mm in length. These cells are widely used in laptops, flashlights, electric vehicles, and DIY electronics projects due to their high energy density, reliability, and long cycle life. In cybersecurity, 18650 cells can be relevant when assessing the power supply security of critical devices, as compromised or low-quality cells may pose risks such as overheating, fire, or device malfunction. Proper management and sourcing of 18650 cells are important to ensure both device safety and operational continuity.