Here's a couple solar powered electric bicycle design ideas..
http://www.lifeinthefastlane.ca/amazing-bicycle-powered-by-the-sun-invented/weird-science
In one case it has a canopy which goes over the top of what's effectively a recumbent bicycle. That kind of steering mechanism is right out of recumbent-land. The top of the canopy has a solar panel. I think the canopy can improve aerodynamics and provide a little protection from weather. But I suspect the solar panel would do very little to help.
The other is a more typical bicycle, specifically a Charger bike, with two rigid panels. The panels in this case look like they'll detract from aerodynamics.
Now that I look at this I think there's a better way to do solar panels for an e-bike. Instead of having the panels deployed while riding, they should be stowed in panniers during the ride. They won't contribute much electricity during a ride so why have them deployed during the ride where they're going to interfere with aerodynamics? You could deploy them while the bike is parked.
David
I think panels would make sense in a area where you do not have access to plug in recharge power. My parents house in the mountains is off the grid, that would be perfect for a Photovoltaic solution to recharge bike batteries. One other thing that might work is, say you are going cross country and have a bike trailer with solar cells on it, that might make sense. Otherwise I think most people would be better off putting their money towards a longer range battery allowing them to get to plug in recharging power.
Deron.