So batteries are too expensive, but space launches aren't? Even assuming the light can be sufficiently focused to bypass the inverse-square law, it'll still need precision manufacturing to actually deliver the power to the panels reliably. And that's assuming mirrors are enough, and you don't need space-side solar panels and microwave/laser beams (which will be even more expensive than hundred-mile-focus mirrors).

Push am (ever so slightly) larger fraction of the sun's energy output into our atmosphere, what could possibly go wrong!

I know, the amount of net electricity per added total energy might end up no worse than in a fusion power best case scenario, but still... When you add the climate effect of re rocket launches required I don't think it could ever become worthwhile.