Industrial rack-mounted uninterruptible power supplies (UPSs) are used in data centers or telecom central offices to provide backup power for servers and switching equipment in the event of failure. Historically, UPSs have relied on lead acid as the predominant battery type. With the introduction of the Open Compute Project (OCP) initiative and hyperscale data centers, lithium-ion batteries are gaining market share over the incumbent lead acid battery technology.
This article presents some of the fundamental considerations and tradeoffs when selecting a lithium-ion UPS system. Several critical considerations include the available chemistry options of lithium-iron-phosphate (LFP) versus lithium-nickel-manganese-cobalt-oxide (NMC), expected discharge time, active versus passive cooling, options for scalability, and the ability to support peak shaving as a secondary function.