I started off with some sketches of LaCie's existing Rugged hard drives to get some ideas flowing.
This page is a summary of my existing experience with portable battery chargers and the problems I currently have with them.
This idea isn't grounded in reality at all, but one major problem I currently have with my Xiaomi charger is its build and weight. The downside of its aluminium construction is the heft that comes with it and the sharpness of the edges which always make me scared I'll scratch something else in my backpack. This led me to thinking about soft, or even flexible chargers that won't harm anything else around it.
At the end of my explorations, the final idea I had solved the problem of tangled cables by hiding the cable within a small slot that both protects it and makes it easier to locate.
I had one more idea though, and despite it being so late at night (or early in the morning) I wanted to put it down on paper anyway.
This concept is a modular battery stack that solves the problem of slow recharge times with increasing battery sizes. Instead of waiting for your battery pack to slowly fill up, you can simply swap out the modules that are empty and replace them from the stack with a fresh one.