Do you need those little connection pieces at the hinges to stay together? If that is what's wrong, it's because you didn't merge the vertices. Or maybe you thought you did, but you have face-caps in the way (you might need to delete the faces where 2 pieces connect in order to merge the vertices).
I don't really notice any "bendiness" unless it is happening at those little pieces and I can't see it so well. You can fix that by weight painting each solar panel solid red for only it's associated bone's vertex groups (and paint that region solid blue for all other vertex groups): select the mesh, go to "weight paint" mode (chosen from same drop down as Edit/Object modes dropdown). Press the N key. Click the weight paint tab in that menu if it isn't already open. Scroll down until you see the part that lets you control the Falloff. Select "constant" falloff. This will paint vertices a solid color.
Now go into the Data panel (the tab on the right that looks like a green triangle) and you will see your vertex groups for each bone. Select and work on those one at a time, coloring each vertex between the 'hinges' solI'd red (or erasing color if necessary) so each bone affects ALL of just one panel and it's half of those little end pieces.
That will do it. Easier than it sounds. Might take you 5 minutes.