Boosting UPS Performance with Lithium-ion Technology

Nick Shanley is the USA Sales Manager, Data Center, at Saft.

Almost every digital function in the world relies on data centers. They are becoming increasingly important to businesses for a number of reasons, such as streaming video services, processing customer transactions, providing employees with cloud computing and running e-commerce sites.  

The Cost of Data Center Downtime

So, as you can imagine if any downtime occurs it can be costly for businesses in more way than one. For an e-commerce site, it may be difficult to update production information or track sales. Problems could be simply annoying, with employees not being able to access files that they need. Alternatively, they could have serious financial implications, like the power outage that British Airways experienced in May 2017. A power interruption at its Heathrow data center resulted in the cancellation of 726 flights, many items of lost luggage, a financial loss of $108 million and damage to its reputation.

In total, the cost of downtime at a typical data center is estimated at $9,000 per minute so it’s vital to do all your research when investing in a reliable back up system as this plays an important role in reducing the number of outages. A well-designed UPS (Uninterruptable Power Supply) associated with an advanced battery system will ensure that even when power problems happen, operations will still be continuous with no down time.

UPS systems use battery power ranging from one to 15 minutes to maintain power until the switchgear swaps to an alternative utility supply, diesel generator or safely shutdowns down operation to another data center. UPSs can also act as a power conditioner by absorbing or injecting power to overcome the short-term spikes and sags in mains power. These are usually caused by voltage transients when other large grid-connected loads are switched on and off.

Leveraging Li-ion Batteries for Back-up Power

Recently there has been a shift in data centers from relying on Valve Regulated Lead-Acid (VRLA) batteries to Lithium-ion (Li-ion) batteries. In the next five years, it is expected that Li-ion will take at least 10 percent of the market share.

This is for a number of reasons. One of these is that Li-ion brings higher power capabilities and has greater energy density it can deliver more power with a reduced footprint and lower weight. Li-ion batteries can be up to three times more compact and six times lighter compared to VRLA batteries. In addition, it has higher cycle life than other battery technologies, which means that it has a longer life. In addition, they work more reliably in higher temperatures, requiring less cooling so reducing the batteries footprint.

While there are several types of Li-ion chemistry, those comprised of iron phosphate are ideal for industries and mission critical applications where safety, power density and calendar life are important. Li-ion batteries come with high availability, with no risk of sudden death, low maintenance requirements and fast discharging rates. This minimizes the risk of unplanned outages in data centers.

They can also be charged at much faster rates, increasing their availability after an outage or discharge. VRLA batteries normally need 12-24 hours to recharge, however, some can take as little as 75 minutes with the high-powered version taking just 15 minutes.

Staying Smart Prevents Failure

When predicting the lifetime of lead acid batteries, it can be difficult to know when they are reaching the end; and VRLA batteries can suffer from sudden death, where they lose all function completely overnight. So, it’s hard to judge if backup power will always be available. Data center operators either have to accept this risk or invest in further redundancy.

However, Li-ion battery systems can be equipped with smart monitoring so their State Of Charge (SOC) and "health" (SOH) can we be checked at any time by the operator. As a result, operators can make an informed judgement around when the batteries need to be replaced and don’t waste money on replacing them too early. It also prevents a loss of critical back-up power by eliminating the chance of sudden death.

Surviving the Heat

Applications that require higher operating temperatures are best suited to Li-ion technology batteries as it has the ability to withstand higher temperatures than VRLA batteries. As a result, data center operators will need to use less energy for cooling, helping to reduce their Power Usage Effectiveness (PUE).

These batteries can work at full performance for up to 20 years at 20 ̊ C. However, a VRLA battery under the same conditions would suffer reduced calendar life and degraded performance, so cooling equipment would be needed.

So, by investing in a Li-ion battery system, the size of HVAC equipment can be reduced, decreasing CAPEX and over the lifetime of the batteries there will be less energy consumption, decreasing OPEX.

Small and Mighty

In addition, because Li-ion has a higher power density and is more lightweight than VRLA batteries, data center operators can now switch to smaller and lighter batteries. By doing this, it makes the handling of batteries easier and minimizes the amount of space they take up. For enterprise and co-location data centers this could enable significant infrastructure savings and increase server space. 

Lithium-ion batteries are now used in everyday life from cell phones and tables to mega-watt energy storage in grid stabilization and solar applications, they are everywhere.  Data center applications are requiring less space, smart understanding of all equipment, faster up-times and optimization of the overall ecosystem including HVAC. Lithium-ion batteries can deliver the requirements of the data center of today and the future as use and critical needs keep improving and growing.

Opinions expressed in the article above do not necessarily reflect the opinions of Data Center Knowledge and Informa.

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