A lot of modern digital devices have their own battery power source in them due to the requirement to be carried around or in locations where electricity from the mains isn't available. Based on the use of the device the portable power source could have various features.
These are only a few examples of the variety of devices that require custom battery packs and the factors that need to be considered when creating mobile power technologies.
There are some that require the charge for a short period of time, or over a prolonged period of time, with intermittent peaking, while others might require the power required for an extended period of time; however, they will require a fast recharge capacity.
Since the introduction of the Mobile Telephone and the advancement of Laptop computing as well as Smart Phones, Battery Pack technology has been advancing rapidly over the last 10 years with improvements being developed every week.
These instruments have redesigned their design so that the power consumption cost has been reduced significantly along with the customized battery packs that they utilize have improved in efficiency to provide more power to longer periods of time, and more rapid recharge times and are significantly lighter.
These advancements have helped in the commercial growth of these well-known handheld devices and have allowed for a massive expansion in their usage.
The fact that they are also able to be carried throughout the world without being noticed (where they had to be powered by a source that was the size of a car battery to power it) has led to their widespread use across all walks of life and across all continents.