An ultra-fast battery charging system
Increased awareness of the effects of atmospheric pollution, especially in inner city areas, makes the use of electric vehicles more appealing. The lead-acid battery is one of the most viable power sources for such an application, due to its low cost. Unfortunately, it is one of the heaviest of such systems in use (in terms of energy stored per unit mass), and is traditionally slow to recharge. This can make it impractical for use in an electric vehicle as the largest usable battery only has a low capacity, yielding a short range. If electric vehicles are to become more commonplace, technological advances in the lead-acid battery system must be sought, not only to increase capacity, but also to reduce the charge time. It has been shown, using a constructed novel resonant power converter, that the overall charge time of a lead-acid battery can be reduced by a factor of five by employing a pulse charging technique, with further reductions possible, whilst evolving significantly less gas than a standard constant-current, constant-voltage technique. This increases battery life expectancy, especially in sealed cells. This method has also been proven suitable for recharging dry cells. It has also been shown that pasted plate cell performance can be improved by redesigning the grid structure. An increase in electrode current of 5%, and reduction of 25% in the lead used are both possible, without compromising cell performance. This is important for applications where portability is important. Lightweight electrodeposited lead plates are a feasible alternative to conventional pasted plates, although careful design is required to minimise cell weight.