Can I embed this charger in a project?
Your can attach a charger to the battery, and use the device at the same time.  There's nothing special about charging the battery versus using the battery.  The portion of the input power the device doesn't use, will go into the battery.  

The only restrictions on this are that the charger isn't overloaded by the device's power requirements, and that the device doesn't take so much that the battery doesn't get a chance to charge.