ELI5: Explain Like I'm 5

High capacity oceanographic lithium battery pack

High capacity oceanographic lithium battery packs are special batteries that are used for special activities underwater. These batteries are made to last a long time and provide a lot of energy all at once. They work like normal batteries, but can hold a lot more energy for a much longer time. Oceanographers use them when they go underwater for long periods of time, like on scientific research trips in submarines. This way, they don't have to worry about their batteries running out and can stay underwater for as long as they need.