Individual solar cells must be ganged in series to provide sufficient voltage for battery charging
. There is basically no way to get around a minimum number of cells in a series. Many panels have two parallel series groups so you you only loose half the panel if the shadow only passes over that side of the panel. The other way to avoid this problem is to use many smaller panels in Parallel. That way you loose a smaller percentage of your output if individual panels get shaded. It ends up being more expensive, but it will work.