A bipolar battery being developed in the UK could make hybrid cars more affordable.
Mansfield-based Atraverda is developing a prototype battery, based on a plate of conductive material, which weighs around half that of existing lead-acid designs but costs far less than the smaller nickel batteries used in hybrid vehicles such as the Toyota Prius and Honda Insight.
Nickel batteries cost £2,000-£2,500, while the cheaper lead-acid batteries used in conventional cars cannot be built at a voltage high enough for hybrids without becoming too large and heavy, said Dr Andrew Loyns, chief executive of Atraverda.Standard lead-acid batteries consist of separate plates for the positive anode and negative electrode, which are built up in number to increase the voltage.
In contrast, Atraverda has developed a conductive plate made from a form of titanium oxide. The positive components are placed on one side of the plate, and the negative elements on the other, reducing the size of the battery considerably.
Standard batteries also contain a large number of inactive parts, which do not contribute to the generation of power, as the plates all need to be joined together, said Loyns. ‘They are also smaller and lighter so we will be able to get close to nickel batteries in terms of size and energy levels, but at lead-acid prices.’
Atraverda is making a prototype bipolar battery, capable of producing more than 9kW of peak power, for feasibility tests as part of the EC’s Astor project (Assessment and Testing of Advanced Energy Storage Systems for Propulsion and Other Electrical Systems in Passenger Cars), which involves eight European car makers, including BMW and Fiat.
The battery can also be used in 42V electrical systems, said Loyns. Existing automotive electrical systems are 14V, but since the 1990s car makers have been investigating a move to a 42V system to meet the rising power demands.
The change would allow more electrically-powered systems to be introduced, fuel efficiency to be improved and emissions such as carbon dioxide to be reduced.