Li-ion technology for UPS systems brings efficiency and savings
A new Schneider Electric white paper argues for the use of Lithium-ion technology over lead-acid battery systems in uninterruptible power supplies
31 January 2019 | 0
Schneider Electric has released a white paper providing guidance on the use of Lithium-ion (Li-ion) technology in uninterruptible power supply (UPS) systems, as Li-ion batteries become increasingly popular in edge computing and larger data-centre applications.
In a free white paper entitled “FAQs for Using Lithium-ion Batteries with a UPS”, Schneider Electric provides guidance on essential topics concerning Li-ion batteries in a question-and-answer format.
The white paper begins with an introduction into the basic science underlying Li-ion and traditional valve-regulated lead-acid (VRLA) batteries and then describes the various advantages and disadvantages Li-ion batteries have over VRLA batteries, the various types in use, and notable information surrounding their use and production.
With regard to the operating expense (OPEX), the Li-ion system has a clear advantage, says the white paper. Over a 15 year period, VRLAs would have to be replaced two to three times, whereas Li-ion systems may require none, or possibly one, replacement — significantly reducing costs and reducing the amount of maintenance required.
Li-ion batteries can also offer savings in cooling technology as the battery life cycle is sometimes specified at a higher temperature, 40C compared to a lead-acid system of 20-25C.
In general, a Li-ion battery system for a UPS will take up 50-80% less floor space and weigh 60-80% less than a comparable lead-acid system. These savings are due to the very high specific energy (energy density) typical of Li-ion batteries. The specific energy rating for Li-ion batteries available today range from 70Wh/kg to 260Wh/kg, with most being in the 120-200Wh/kg range. By comparison, a typical lead acid battery is in the 30-50Wh/kg range, says the white paper.
Analysis carried out by Schneider Electric has shown that, in general, Li-ion-based UPS systems have a total cost of ownership (TCO) that is 10-40% less (as of 2016) than that of a VRLA system, over a 10 year period.
These benefits do come as a premium to the consumer however and is the main factor in why the uptake of Li-ion technology in UPS systems has been slow. The white paper says that the installed cost of a Li-ion system is approximately 1.2-2 times more, as of 2018, than what it would cost for a VRLA battery system, at the same power level and runtime.
However, it is worth noting, that this cost difference was 10-times that of a VRLA system only a few years ago. With the decrease in cost, future technology enhancements, and additional gains in manufacturing efficiency, the white paper notes that this will likely lead to further cost reductions in the coming years.
Depending on the design configuration of a UPS system, it may also be possible to substitute Li-ion batteries for the existing VRLA units, with only a change in firmware required. However, this will depend on other elements of the UPS such as the inverter, charger and mechanical design being compatible with the different batteries.
The white paper can be read in full here.