Impact on global metal flows arising from the use of portable rechargeable batteries

The use of portable rechargeable battery cells and their effects on global metal flows were assessed for the following three cases: (1) the base case, which reflects the situation in 1999 of the global production of batteries; (2) the global production of portable nickel–cadmium batteries in 1999, assumed to be replaced by other battery types; and (3) assessment of the projected battery market in 2009. The study included the following battery technologies: nickel–cadmium (NiCd); nickel–metal hydride (NiMH) (AB5, AB2); and lithium-based batteries (Li-ion: Co, Ni, Mn; Li-polymer: V). Based on the lithospheric extraction indicator (LEI), which is the ratio of anthropogenic to natural metal flows, and the significance of battery production related to global metal mining, the potential environmental impact of metals used in different battery types was evaluated. The LEIs and average metal demand for the battery market in 1999, expressed as a percentage of global mining output in 1999, were estimated to be as follows: Ni 5.6 (2.0%); Cd 4.4 (37%); Li 0.65 (3.8%); V 0.33 (6.5%); Co 0.18 (15%); Nd 0.18 (8.4%); La 0.10 (9.5%); Ce 0.083 (4.4%); and Pr 0.073 (9.4%). The use of Ni and Cd is of the greatest environmental interest, due to their high LEIs. In the case of complete replacement of portable NiCd batteries by NiMH or Li-based batteries, the LEI for Ni (5.6) would change by −0.1–0.5% and the LEI for Cd would decrease from 4.4 to 3.0 (−31%). Meanwhile, the mobilization of metals considered less hazardous than Cd (LEI<0.65) would increase less than 7%. Based on this assessment, the replacement of NiCd batteries would result in decreased environmental impact. To decrease the impact on global metal flows arising from the use of portable batteries the following points should be considered: (1) development of battery technologies should aim at high energy density and long service life; (2) metals with high natural occurrence should be used; and (3) metals from disused batteries should be recovered and regulations implemented to decrease the need for mining of virgin metals. The method used enables an assessment early in the cause–effect chain, when few data about toxic effects are available. It can also be used to assess whether environmental problems are shifted from one to another.