This idea is still in progress.
The hole idea is to use the sun as a charger.
Sometimes people are in a hurry for a appointment with there friends to have a nice beer at a sunny day. While you are running to your appointment, you suddenly remember you forgot to charge your phone. But luckily you have your portable solar key with you. So you can charge your phone while you drinking a nice cold beer at a sunny day.
For now one you can always charge your mobile. And i'm sure you won't forget to take this portable charger with you, because this product is together with your keys (house key(s)).
REMEMBER, I STILL NEED TO DEVELOP THIS PRODUCT