A power bank is a portable device that stores electrical energy, allowing users to charge their electronic devices on the go. It typically contains a rechargeable battery and has one or more USB ports for connecting devices like smartphones, tablets, and other gadgets. Power banks come in various sizes and capacities, making them convenient for travel or daily use. To use a power bank, simply connect your device to it using a charging cable. Once connected, the power bank transfers its stored energy to the device, providing a quick and efficient way to recharge without needing a wall outlet. Many power banks also feature built-in safety mechanisms to prevent overcharging and overheating.