ony way you can charge a device is via the method it retreives power. for a laptop this means one of two ways:

1. Power socket
2. Battery terminals

There isn't another way. The bottom line is that a laptop requires a lot of power, and even if you try and just charge the battery, your looking at a very small use time from the battery compared to how long it would take to charge. I'm not going to get into specifics, but your looking at very large panels to power a laptop.