Storyboard Phase:

The aim in this phase is to show the creative concept, messaging and direction of the story. Rough camera angle and movement are also shown to support the explanation of the concept. Depending on the size of the project, there may be several iteration of the storyboard.
See example here.

Animatic Phase:

An animatic is basically a moving storyboard. Using basic shapes,models and pictures, this phase aims to determine the:
1) timing i.e. what is the length of the animation, what are the lengths of each scene etc
2) basic animation of all major objects in the story.
3) determine the best camera angles
See example here.

Later iterations of the animatic will replace the basic shapes/models and pictures with more detailed models, textures, particle effects, refined animation and any creative changes.
See example here.

Final Render Phase:

Once the final animatics has been signed off, the final animation is then rendered and post-produced (i.e. adding special effects, colour correction, 2D animations etc etc).
See example here.