The most common reason cited is the significantly longer service life. Lithium-ion also provides a greater cycle life (the number of charge/discharge cycles ranges from 5000 to 9000, versus approximately 500 for VRLA batteries), as well as a longer warranty. Furthermore, the lighter weight and smaller footprint are additional benefits.
In addition, IT professionals can easily deploy lithium-ion UPSs without the maintenance and refresh challenges of those utilizing lead acid. The extended battery life provided by lithium-ion enables users to align their UPS refresh cycles with the rest of IT stack, saving time and money spent on labor and replacement batteries. Furthermore, lithium-ion UPSs boast a “set it and forget it” value proposition, which is especially conducive at sites where UPSs protect critical network operations yet IT resources are not extensive.
In general, they vary from slightly more expensive than good-quality VRLA, to two to three times more expensive, especially when shipping costs and commissioning services are considered. Lithium batteries can be sensitive to high temperatures during transit, requiring manufacturers to ship loose batteries in refrigerated trucks at a 30 percent state of charge (SOC). In addition, Eaton requires a customer service engineer to be on site for large battery cabinet startup service, which isn’t needed for VRLA batteries.
It is important to note that in the near future, when vendors start shipping battery cabinets pre-loaded with batteries, we expect the shipping costs for lithium batteries will actually be slightly less than that of VRLA batteries.
If the battery modules are connected together, i.e. installed in a cabinet, the storage times are six months at 25 degrees C. This is due to parasitic losses from the BMS.
If the battery modules are NOT connected together (either power or communication connections), then the storage times are one year at 25 degrees C.
Note: Samsung requires a "voltage check" of the batteries every 180 days during storage.
With the absence of a standardized commissioning test for lithium batteries, we expect that commissioning would be somewhat similar to that of VRLA, and should include the following:
Lithium-ion batteries are disposable and, while currently not readily recyclable, new options are expected in the future.
To read more about recycling lithium-ion batteries, visit Eaton's battery recycling page.