Life Evaluation Of Valve Regulated Lead-acid Batteries For Cycling Applications

Argonne National Laboratory (ANL) is conducting a life evaluation of valve-regulated lead-acid (VRLA) batteries for cycling applications. Two technologies are being evaluated: (1) gelled-electrolyte modules from Johnson Controls, Inc. (JCI) and (2) absorbed electrolyte modules from GNB, Inc. A matrix of operating temperature and depth-of-discharge (DOD) conditions is being used to accelerate in the end-of-life for given modules. In May 1989, two modules from each manufacturer were placed on life test at 30{degree}C (80 and 100% DOD), and third module was placed on accelerated life testing at 50{degree}C (100% DOD). The GNB module operating to 100% DOD at 30{degree}C still retains {approximately}87% of its initial capacity after{approximately}470 cycles. The GNB module operating to 80% DOD at 30{degree}C has accrued {approximately}600 cycles and retains {approximately}92% of its initial 80% DOD capacity. After a high-temperature charge procedure was established, a fourth GNB module was placed on test at 50{degree}C (80% DOD) in September 1989. Both GNB modules tested at 50{degree}C have accrued {approximately}170 cycles; the 100% DOD module retains {approximately}84% of its initial capacity, and the 80% DOD module retains {approximately}89% of its initial 80% DOD capacity. Only one of the gelled-electrolyte JCI modules remains on test (30{degree}C, 80% DOD). It retainsmore » {approximately}86% of its initial 80% DOD capacity after >450 cycles. The other two JCI modules were removed from test because they reached end-of-life. Teardown analyses at JCI indicate that a manufacturing defect caused premature failure of one module. The second module is undergoing teardown analyses at ANL. 2 refs., 5 figs., 5 tabs.« less