Thursday, 24 January 2008

Improvements in lead-acid batteries.

Some good news for the hybrid and electric car market - further advances on lead-acid batteries see the prospect of a 250mile, rapid charge EV closer.

The chaps over at the Commonwealth Scientific and Industrial Research Organisation in Australia have been combining within the battery casing the components of an accumulator - i.e. battery - and a capacitor. Batteries can store large amounts of charge and retain it for a long time, but are not very good at absorbing and releasing it quickly - doing so tends to create heat and damage their chemistry. Capacitors, on the other hand, can be charged and discharged very rapidly many thousands of times, but they have limited bulk storage and tend to let charge leak away fairly rapidly. Combining the two has been done many times before, but within the same carcass is innovative.

Capacitors are key as they enable regenerative braking to be adopted. It makes electric and hybrid cars extend their range significantly, for, once this is in place, the energy put into acceleration and hill climbing are recouped*. Cars like the Toyota Prius do not have regenerative braking as their battery systems are incapable of absorbing the significant amounts of electrical energy produced. Even if they did have a capacitor, the Toyota's motor, which would work as the regenerative brake, is just too feeble to perform the task. As I blogged earlier, a Mini with near total conversion drive and braking needs 640bhp - 160bhp at each wheel to perform braking. It makes for a quick little car, though, and the full regenerative braking means the range is significantly extended.

Cars like the parallel hybrid Prius are clumsy, over complex and not really efficient at all - a decent French diesel could do better and be more fun to drive**. It is a shame they went down that path for a series hybrid - no mechanical connection between engine and wheels - has been out for over 100 years!

One day. One day. And today, that day gets closer.

*except for wind, rolling and conversion losses.
** unless you count being an ignorant no-nothing smug twat fun.

1 comment:

Mark Wadsworth said...

Looks very promising.