Right battery size for the purpose is an important choice
Ricardo released a new Life Cycle Assessment (LCA) study for the Low Carbon Vehicle Partnership (LowCVP), concerning various types of vehicles and noticed big differences in environmental impacts depending on powertrain type over the entire life of the vehicles (manufacturing and driving).
One of the important things is that battery-electric vehicles affect the environment mostly during the production process (20-95% of the total over entire life), as they don't emit any CO2 or GHG while driving (even emissions from power plants are relatively low). Battery production will be the single-biggest factor we believe (because it's the heaviest and biggest part).
Typically, BEVs notes 40-60% lower CO2 emissions than internal combustion engine cars, but benefits could be decreased/lost if vehicles are equipped with two or three times bigger batteries (at least until higher capacity is not the result of a technological progress, but increase of the size of the battery).
"For electric and plug-in hybrid vehicles the carbon intensity of the power grid is, of course, also a key factor in terms of the vehicle’s full life cycle emissions. Well-to-wheel CO2e emissions of current electric vehicles are already significantly lower (40-60%) as a proportion of full lifetime emissions than those of typical current passenger cars (70-85%) and this difference can increase as the electricity grid becomes increasingly decarbonised. However, if a race for bigger and bigger batteries is left unchecked, EVs doing low mileages could undermine some of the potential benefits."
The problem is especially big if mileages remain low and people start to carry unnecessary batteries in their long-range BEVs. Moreover, weight will affect other parts of the vehicles like tires.
That leads us to the conclusion that battery capacity should increase within the size and weight of the current or even previous generation of electric cars instead of turning cars into battery-haulers. The other conclusion is that customers should have choice to purchase particular cars with smaller or bigger batteries, depending on rational needs.