Can Lithium-Ion Become The UPS Battery of Choice

Uninterruptible Power Supply systems typically use lead-acid batteries to provide power in case of an outage, but these solutions have not evolved much in the past few decades.

As backup power specialists with over 20 years’ experience in the industry we have installed and maintained thousands of UPS batteries across the UK.

However until the last few years, the only viable solution for backup storage in a UPS was to use Valve Regulated Lead Acid (VRLA) batteries.

With significant improvement in both the design and the production of Li-ion technology we are now getting asked more by our customers about lithium-ion alternatives.

At the same time, we are seeing the major UPS manufacturers that we work with offering Li-ion solutions in some of their product ranges, particularly in the data centre environment.

With space in comms rooms and data centres at a premium and organisations wanting more energy efficient solutions that have a lower cost of ownership and are friendlier to the environment, perhaps the advantages of li-ion will make this the industry standard in years to come.

As other industries like electric vehicles and smart phones have embraced this technology, it may not be long until li-ion batteries are commonplace in providing backup for UPS systems.

In this blog, our technical director Tony Quince looks at the benefits of Li-ion as an alternative to VRLA but also considers some of the questions that are being asked of this alternative battery technology.

The key difference between a Li-ion battery and a lead-acid battery is the mix of chemicals used in the electrodes and electrolyte within the battery.

Li-ion batteries use a metal oxide for the cathode, and a carbon-based material for the anode. The electrolyte is a lithium salt dissolved in an organic solvent.

A lead-acid battery uses lead dioxide for the cathode, a lead anode, and sulfuric acid as the electrolyte.

Whilst VRLA batteries remain a popular choice for Uninterruptible Power Supplies and will continue to do so in the next few years, there are some key advantages that come with Li-ion technology including:

• Up to x2 longer battery life.
• Less weight and easier to install.
• Smaller footprint to take up less space.
• Faster recharge time.
• Able to withstand higher operating temperatures.

Whilst costs are falling as developments in technology pick up pace, Li-ion batteries are generally more expensive than lead-acid batteries, but probably one of the most obvious advantages to compensate the initial extra outlay is that Li-ion batteries last considerably longer than Lead Acid batteries.

More information can be found on our battery replacement page but typically, over a 15 year life of a UPS, the lead acid batteries would need to be replaced two or three times depending on their operating environment.

All lead acid batteries are prone to natural decay and depending on the make and model, most batteries have a design life of between five and ten years.

To avoid any unnecessary and costly downtime should you get a mains power failure, our experts recommend changing VRLA batteries as follows:

• Every 4 years for a 5-year battery life
• Every 8-9 years for a 10-12 year battery life

The real advantage for Li-ion systems is their extended lifespan. In some cases, you may never need to replace a Li-ion battery during the operating life of a UPS resulting in lower cost of ownership (TCO) and lower maintenance costs due to no battery replacements under normal circumstances.

Depending on chemistry, technology, and temperature, Li-ion can provide a greater cycle life as the number of charge/discharge cycles range from 5000 to 9000 for li-ion compared to approximately 500 for VRLA batteries.

This can result in an extra life of the battery of between 8-10 years.

Li-ion batteries provide multiple times the energy and power density compared to valve-regulated lead-acid batteries so take up a much smaller space delivering the same power.

A UPS using Li-ion batteries takes up about one-third of the space or less of a VRLA supported UPS that delivers the same power.

Combined with a 60-80% weight advantage over a VRLA battery, Li-ion batteries are easier to install in racks providing more flexible installation options.

With a significantly reduced footprint, li-ion batteries deliver more runtime in a much smaller space. Particularly relevant in data centres where floor and rack space become increasingly squeezed.

Li-ion batteries also generate less heat and can operate at much higher temperatures than lead acid, meaning they don’t require as much air conditioning, which can reduce cooling costs. 

Li-ion batteries can also withstand higher ambient room temperatures than VRLA batteries with little effects on the performance of the battery.

Yuasa, one of the market leading UPS battery manufacturers we work with produced a fantastic Little Red Book of Batteries guide where they state that the battery life of a VRLA battery is reduced by half for every 10 degree increase above 20 degrees in the ambient room temperature.

However, Li-ion batteries are much less sensitive to fluctuations in room temperature and spikes in temperature.

Unlike VRLA batteries, Li-ion batteries come with a sophisticated battery management system (BMS) that provides a clear indication of battery runtime and battery health.

Around 70% of UPS power failures are due to undetected faulty batteries which are difficult to detect in lead acid batteries due to the makeup of the battery.

This would normally require a remote battery monitoring solution to ensure the battery setup is under constant review. This acts as an early warning system to any potential battery failure to individual blocks or whole strings.

Batteries are an important part of any UPS setup and therefore regular testing and maintenance is essential to keep a long life cycle of VRLA batteries.

However, the integrated monitoring system in a Li-ion battery monitors individual battery cells for any change in performance against temperature, current fluctuations and over or under charging issues.

Similar to the Li-ion battery on your smart phone, the BMS allows you to easily see how much battery life is left at any given time. It will also optimize the battery charging on an ongoing basis to maximize performance and increase the life of the battery.

With all new technology there will be pros and cons so it would be remiss of us to only highlight the benefits of Li-ion batteries before any decisions can be made.

There are a lot of benefits of using Li-ion batteries due to their smaller footprint, longer lifecycle, and integrated battery monitoring capabilities but this does come with a price meaning the initial investment is significantly higher.

Perhaps this is why large data centres have been early adopters with Li-ion as it helps reduce long term total cost of ownership and less about short term benefits.

Another thing to think about is the availability of the technology. With the major brands we work with there are still only a few of the products that support li-ion technology.

To help highlight those products we now have a dedicated Li-ion section to easily show what products are available.

We have discussed the use of Li-ion batteries in mobile phones and electric cars where these are commonly found, however the requirements and development of Li-ion batteries used in an Uninterruptible Power Supply are very different.

Batteries found in EV’s and mobile phones are designed to store lots of energy to last the longest it possibly can on a single charge.

The requirement for a UPS battery is usually to provide backup power for a few minutes up to a couple of hours depending on the UPS setup so the battery solution needs to be reliable and safe with a long life expectancy.

I hope from reading this blog that you have a better understanding of Li-ion battery technology but if you want to discuss anything about li-ion then get in touch with us today.

With over 20 years’ experience in supplying installing, maintaining, and replacing UPS batteries across all sectors our experts are the right place to start your li-ion journey.

Working with all the major UPS manufacturers such as Riello UPS, APC, Eaton, Socomec and Vertiv we can point you in the right direction whether its Li-ion or VRLA batteries you require.

Contact us today to find out how we can help with your power backup needs.