I am trying to set a dynamic id to my div within my ng-repeat. Let me show an example.
To answer your question, try this:
While the above should work, this might be not what you want really (!). Please note that this is rather rare with AngularJS to manipulate elements by referring those by id.
You should focus on your model, declarative describe UI and let AngularJS do the rest without doing low-level DOM manipulations "by hand".