Yes, there is a grip and it contains an extra battery. That will double the capacity.
The grip is an add on accessory – it does not come with the camera. However, those who pre-ordered in the initial order will get a free grip.
There is the possibility of a grip in the future which will provide image stabilisation, as described at 50:10 here: spot.light.co/the-l16-under-the-hood/. Maybe such a grip might be made available when the video capability is added.