It seems as though the battery is failing to hold its charge and needs to be replaced. Even rechargeable batteries have a life span.
Unfortunately as I cannot find a guide on how to open the tablet to gain access to the battery, I'm hoping that this guide on how to replace the battery in an Irulu ax106 will be very similar to your model and will be of some help.
iRULU AX106 Battery Replacement
Here is a link to a supplier of a replacement battery for your tablet. It is not a recommendation to use them, it is shown just to give an idea of the price of the battery. there are other suppliers that may suit you better. Just search for Irulu ax922 battery for results.
Hopefully thisi sof some help.