AVESTOR/spl trade/ lithium-metal-polymer batteries: conclusions to be drawn from field trial results

AVESTOR has developed a revolutionary design for stationary lithium-metal-polymer (LMP) batteries, a first in the industry. Through 20 years of extensive research and development, AVESTOR´s efforts have resulted in a battery that offers new levels of high energy density, reliability and long life under the most extreme environmental conditions. The AVESTOR LMP battery is now into its commercialization phase with the telecommunications sector being the first commercial market. In this paper, data collected from AVESTOR IMP battery systems in uncontrolled environments will be analysed. AVESTOR has been monitoring almost 100 batteries, installed in nearly 30 field trial sites in telecommunications stationary applications chosen by the telecom operators, some of which have been in service since 1999. In these sites, AVESTOR LMP batteries replaced existing lead acid batteries and have been supporting real service loads and been subject to event-triggered discharges as well as forced discharges. Lithium-metal-polymer batteries in these trials operated in harsh environments and, in most cases, regularly experienced very high temperature conditions. At each field trial site, forced discharge tests were performed on a regularly scheduled basis. Forced discharges were provoked by disconnecting the site primary power source and allowing the batteries to carry the system load for a period of time roughly equal to that expected to utilize the full capacity of the battery reserve. The total field trial plan to date has provided a database covering over 87 forced discharges tests, covering a range of loads equivalent to C/4 to C/22 conditions and discharges that lasted from 2.8 to 21.5 hours. Extensive data has been collected at all installations using AVESTOR´s remote monitoring system. This system, in communication with the battery module´s integrated electronic control system, is able to track individual electrochemical cell parameters, in real time, permitting internal temp- - eratures, cell voltage levels, and current to be studied in detail during charge, discharge or float operation. In this paper, this data is analysed and compared to laboratory data, demonstrating the battery system performance and assessing any impact of real application environments on battery functionality and capacity.