ACEEE factors in the lifetime emissions of the chemistry of the battery.

Some batteries, like NCA, have worse emissions than others.

Also: the grid is mostly coal and nat. gas today. Case in point: the Hummer EV burns more fossil fuels on electricity because it weighs 4 tons.

EV doesn't make anything automatically more efficient. Only the smallest and lightest EVs, like the Leaf, have high environmental scores.