The Use of Lithium-Ion Batteries in Uninterruptible Power Supplies

Uninterruptible power supplies need a stored energy reserve if they are to keep critical loads running during a power outage. It’s coming at a good time because customers are facing some difficult challenges with respect to UPSs, whether they’re for data centers, critical buildings, industrial processes, or critical infrastructure. These challenges are driving the need for specific UPS requirements, including:

More recently UPS manufacturers are offering lithium batteries as a potential alternative but what are the advantages of this type of battery and what’s the roadmap for a lithium UPS battery system?

The Traditional Role of UPS Batteries

● The role of an uninterruptible power supply is to provide a continuous source of AC (alternating current) and to protect its critical load(s). A connected battery set can provide several roles depending on how it is sized:

● To ride through momentary power outages of the type when a storm goes overhead or there is utility network substation switching.

● To provide enough time for a standby generating set to start-up and run-up to full speed. Typically of only 1-2 minutes unless the generator is poorly maintained and/or fails to start.

● To provide enough time for an automated shutdown of the critical loads. This applies principally to small server configurations. Most large server rooms and data centers may take several hours to power down or mirror operations to another site and a planned complete power down is a rare event.

● To provide an extended runtime capability of several hours using battery extension packs in place of a standby generating set.

In addition to the above, the UPS system also protects from mains borne pollution including spikes, sags, surges, and brownouts, and should provide a digitally generated sinewave output whose quality should be more than that can be drawn from a local mains power supply.

Lead-acid or more predominantly valve-regulated lead-acid (VRLA) batteries have become the de facto choice for most UPS applications. The technology is well suited to the passive and standby role of the battery set in its traditional critical power role. Momentary power outages are rare and when they do occur can include one or two or more rapid occurrences and the UPS typically has enough charge to cover these periods. Even during longer mains power supply failures, the battery typically only performs a standby role until the output from a local generating set kicks-in.

When mains power is restored the standby battery is recharged, typically using a not very sophisticated trickle charging system to ensure that the battery is recharged to around 80% within 24 hours. Rapid charging generates too much heat within a lead-acid battery and is life reducing and a potential fire risk.

UPS Systems With Lithium-Ion Batteries

UPS Systems with Lithium-Ion Batteries can be the perfect choice for your three-phase UPS. Lithium-ion batteries offer several advantages over traditional valve-regulated, lead-acid batteries commonly used in UPSs today.   Benefits

Longer life expectancy – Lithium-ion technology can double or triple battery service life, reducing the risks of downtime or load interruption during maintenance or replacement. Lithium-Ion batteries also offer up to 10X the cycle life of VRLA batteries.

More power in less space – Lithium-ion batteries provide multiple times the energy and power density compared to VRLA. As a result, UPSs built with Li-ion batteries take up only about one-third the space of a VRLA-based solution that delivers the same power.

More forgiving in a wide range of temps – Li-ion batteries can withstand a wider temperature range than VRLA batteries.

Reduced cooling requirements and costs – The smaller footprint and wider temp range of lithium-ion batteries can reduce the space needed in a battery room and increase the optimal operating temperature range.

Less weight – Lithium-ion batteries offer at least a two-thirds reduction in weight, at least. That means customers have more flexibility in terms of where they install the systems and can often avoid costly building modifications.

Battery monitoring systems included – Li-ion batteries always come with sophisticated battery monitoring systems (BMS) that provide a clear picture of battery runtime and health.

Lithium-Ion UPS brings a whole new dynamic to the UPS game with smaller and more compact systems and batteries that lithium-ion can provide. With this development, we can see longer runtimes for UPS just on internals and an even longer when you get into EBM territory. These lithium-ion batteries are made to last longer than regular batteries that you buy for UPS which means that the total cost of ownership is lower than normal UPS batteries saving you money in the long run.

For more information about Lithium-Ion Batteries for Large UPS Systems, call +86 752 2819469 or email [email protected].