Li-ion batteries are not without fl

Li-ion batteries are not without flaws. For one, they have a somewhat poor life cycle (300 to 500 charges/discharges). Specifically, the Li+ trans- port is increasingly impeded by deposits which form in the electrolyte and which gradually decrease the conductivity and thus, the current which can be drawn. This requires more frequent charging. Second, the shelf life, i.e. without use, is said to be 3–5 years. Third, elevated temperatures (storage of laptops in hot cars and poorly ventilated laptops!) diminish permanently the storage capacity. Specifically, Li-ion batteries lose irreversibly 20% to 30% of their capacity per year, depending on their storage temperature. (They should be stored in a cool place at 40% charge.) Fourth, power tools which require large currents are better served with Ni-Cd’s or Ni–MH batteries. Fifth, they are expensive to manufacture. Finally, safety concerns, particu- larly for batteries with high energy density (electric cars) and after mechan- ical abuse, have been mentioned already at the beginning. It is, however, anticipated that the above-explained problems will be solved over time.