ADVANTAGES AND DEFECTS:

• When compared to Li-ion batteries, Li-Poly batteries have a higher degradation rate over their life cycle. However, recently, manufacturers have declared that they have reached a number of 500 charge/discharge cycles before the capacity is reduced by 80% (see Sanyo ). Another variant of lithium polymer batteries is the “rechargeable lithium thin film battery” which has made more than 10 000 charge and discharge cycles possible. One of the great advantages of Li-Poly technology is that manufacturers can shape the batteries more or less however they want, this may be important for mobile phone manufacturers who are constantly working on ever smaller, thinner and lighter phones. Another advantage of lithium-polymer batteries over Ni-Cd (nickel-cadmium) and NiMH (nickel-metal hydride) batteries is that the no-load discharge rate is much lower. One of the main flaws of the technology is the need to use specific chargers, to avoid fires and explosions. The battery can explode if short-circuited, due to the very low internal resistance and the resulting tremendous impulse current that flows through the cell. Furthermore, a Li-Poly cell can easily catch fire if punctured, so batteries are, in various applications, covered in a plastic casing which should prevent punctures. In specific applications (e.g. radio-controlled cars), furthermore, electronic torque controls are required for the electric motors connected to the cell, in order to contain the discharge currents and consequently the damage to the battery. A problem with lithium-based batteries is the supply of the raw material: lithium is available in nature in limited quantities and requires particularly complicated and expensive extraction processes; the market is in the hands of a few producers, FMC and CHEMETALL.