Progress towards an advanced lead–acid battery for use in electric vehicles

The attributes which are essential for a battery to be successful as the energy store for an electric vehicle are reviewed. These are then matched against the substantial advances in the technology of valve-regulated lead–acid (VRLA) batteries that have been posted during the course of the technical programme of the Advanced Lead–Acid Battery Consortium (ALABC). A project which was designed to draw together several desirable features, identified during the early years of the ALABC programme, into a test battery has provided much useful information. The design target for specific energy (36 W h kg−1) has been achieved successfully. Cycle-life is short, but it appears likely that an inappropriate charging regime with an unrestricted charge factor was largely responsible. Benchmark tests with a commercial product also yield very short life with this regime, but provide good performance when the charge factor is kept in check. Attention to the deployment of suitable charging regimes continues to be a fruitful area in extending the life of VRLA batteries, and the ALABCʹs programme to enhance both specific energy and life, while shortening recharge time, is making good progress.