Hybrid electric battery solution

Foresight Vehicle brought together experts from the European Advanced Lead-Acid Battery Consortium, battery specialists EnerSys, Provector, Sheffield University and the University of Warwick. When in production, RHOLAB is expected to be £2000 cheaper than the nickel metal hydride units currently in use.

Although it uses acid, there is no free liquid in RHOLAB, the acid being absorbed within a glassfibre separator. The individual cells are round, not square, and spirally wound (like a Swiss-roll cake). Each 2v cell is fully sealed and, while technically each of RHOLAB's four 36v modules needs only 18 cells, the scientists have built in a 19th cell which is part of the battery's secret.

The presence of this cell means that each cell in the 144v unit can be recharged in turn, even when the car is not being driven. An electronically controlled battery management system, purpose-developed by automotive electronics specialist Provector, based near Cambridge, and the University of Warwick, constantly keeps the battery in peak condition.

Conventional lead-acid batteries cannot cope with the high power demands of hybrid cars, but these specially designed cells can. Additionally, existing nickel metal hydride batteries are very expensive and not easy to recycle, unlike their lead-acid competitors which are inexpensive and have a well-established recycling infrastructure.

The inventors have already put the RHOLAB battery, fitted to a Honda Insight, through tests and are planning a full, 50,000-mile trial at the Millbrook Proving Ground.