Marketing Manager

System architecture for traditional lead-acid and nickel-cadmium batteries has evolved in particular ways to meet specific application requirements. For example, valve-regulated lead-acid (VRLA) batteries for telecom outside plant (OSP) are deployed in multiple parallel strings, while vented batteries in utility substations are installed as single series strings. As users in these applications start to consider new technologies such as lithium-ion (Li-ion) there will be a natural tendency to maintain the same system architecture that has worked so well for them over the years. But is this the right decision? Li-ion battery systems include built-in monitoring and communication functions that are required to ensure operational safety. These functions provide a level of sophistication that is not seen in traditional batteries, and, combined with the increased energy density of Li-ion, can seem to make a compelling argument in favor of this new technology. However, with increased sophistication come new failure modes and new complications in battery application, and these issues can have a serious impact if the system architecture and battery integration are not modified accordingly. This paper addresses two applications – telecom OSP and utility substations – comparing existing battery solutions with Li-ion, and how the dc power system can be adapted and optimized to provide for successful application of Li-ion batteries. Recommendations are provided for the user to evaluate competing technologies, with particular reference to a soon-to-be published IEEE standards document