Quite some time ago I got a Powermonkey Explorer set (the one with a solar panel charger) at a substantial closeout discount. After the marketspeak dissipates, it’s a single lithium-ion cell with a boost regulator and USB charger inside a screaming yellow case (the new ones seem more subdued) that’s somewhat water resistant, along with a kit of adapters for various widgets & phones. It stopped charging from the solar panel or a USB port, which suggested that I had little to lose by cracking it open.
It’s an odd shape, but grabbing it across the equator and applying gentle pressure cracked one side:
Wedging a screwdriver in the opening and twisting a bit freed the other side:
Then it was just a matter of pulling gently to expose the cell & circuitry within:
That seems to be a standard 18650, presumably similar to that 2.2 A·h cell.
I didn’t find anything obviously wrong, so I buttoned it up with screaming yellow silicone tape, put it on its wall-wart charger for a bit, and now it’s all good again: a shining example of a laying-on-of-hands repair.
The single button has much more travel than it should, so I think the internal foam supports have lost their springiness.