Using a lithium metal negative electrode may give lithium metal batteries (LMBs), higher specific energy density and an environmentally more benign chemistry than Li-ion batteries (LIBs). This study asses the environmental and cost impacts of in silico designed LMBs compared to existing LIB designs in a vehicle perspective. The life cycle climate and cost impacts of LMBs show a similar pattern: the use phase has more climate and cost impacts than the production phase. As compared to LIBs and with respect to the positive electrode, Lithium Nickel Manganese Cobalt Oxide (NMC) is preferable to Lithium Iron Phosphate (LFP). The cell cost is highly dependent on the cost of lithium metal; a cost reduction of 50% causes a cell cost reduction of 8–22% depending on the choice of positive electrode material and if the cell is optimised for power or energy. For electric vehicle usage, the total cost per km is mainly dependent on the energy consumption per km and the capacity of the positive electrode, representing cost saving potentials of about 10%. These generic results can be used as a base for investigations of other battery technology using lithium metal electrodes.