23 Status of the aluminium battery

In 1997, patents were filed in Finland for a new aluminium secondary battery. The inventor was Rainer Partanen of Europositron Corporation who claims major improvements in power density and energy density for the new cell based on a 1.5 V EMF2. The author is interested in this problem because it represents one of the last major barriers to be overcome before the widespread introduction of electric and hybrid vehicles. In recent years, significant effort has been directed at improving secondary battery performance and this effort is beginning to bear fruit. We can now see advanced lead acid, nickel metal hydride and Lithium Ion products out in the market place with performance of up to 100 Wh/kg and 200 W/kg.

Market requirements fall into two distinct categories: (a) small peak power batteries of 500 Wh (2 kWh for hybrids) and (b) 30-100 kWh for pure electric vehicles. Each of the cell types has its own distinctive attributes but none has so far succeeded in making the breakthrough required for mass market EV implementation. The fundamental problem is one of weight. At the factory gate, vehicle cost is almost proportional to mass, as is vehicle accelerative and gradient performance. Consequently it will take at least 300 Wh/kg and 600 W/kg to achieve the performance/weight ratio for long range electrics we really desire. This would make one type of hybrid particularly attractive - the small fuel cell running continuously together with a large battery.

If we consider a low loss platform for a passenger car at 850 kg with N = 0.3, we have 250 kg for the battery. At 300 Wh/kg we obtain 75 kWh, which would give a range of more than 250 miles after allowing for auxiliary losses. A low loss platform would consume 5 kW at 60 mph + 5 kW for auxiliary losses - total 10 kW - this equates to 7.5 hours at 60 mph = 450 miles steady state. This level of performance is an order of magnitude better than lead-acid at the current time. Clearly a new approach to the problem is required.

0 0

Post a comment