There’s been some threads discussing the panels in those backpacks:
If I were going to use one of those matrices (I have one, unused BTW), I would desolder the controller, and wire up a SmartLED Shield to the matrix signals on the board. It looks like there are HUB75-compatible signals on the board. No one has posted here that they’ve tried it and it works yet.
is there a way to create a led matrix 64x64 that work with a powerbank (5V 2A) ?
I don’t think there’s much special about that matrix to make it work with a power bank. I’ve used some of my matrices (32x32 P6 is the only one I can remember trying) with a powerbank. Just watch that the brightness isn’t too high and you’ll probably have good results.
This doesn’t take care of actually needing to drive the matrix from an Android app. I don’t have many suggestions there.