Changing perceptions: How Li-ion battery technology is carving a bigger niche in the UPS market

In addition, data centre operators are planning for flexibility by opting for modular infrastructure such as the UPS systems that provide backup and power conditioning.

Li-ion batteries fast gaining ground

Until recently, UPS systems featured valve-regulated lead acid (VRLA) batteries. However, Li-ion batteries are quickly gaining market share. This is due to their reduced size and weight, longer lifespan, faster recharge times and, importantly, growing affordability.

Because they are one third of the size and one sixth of the weight of VRLA batteries, Li-ion batteries require less installation space and require less civil engineering and structural support. As a result, they can offer significant savings, especially in city centre sites, where space and infrastructure comes at a premium.

They also offer long-term value due to their long calendar life and cycle life and low maintenance requirements. This drastically reduces the risk of outages and enhances sustainability.

Li-ion batteries can also operate reliably at high temperatures. For example, they can provide full performance at up to 40 ˚C over a life spanning 12 years. As a result, they need less cooling and enable operators to save energy on HVAC (heating ventilation and air conditioning) systems and can reduce carbon dioxide emissions.

In addition, while VRLA batteries require 8-12 hours to recharge fully following a full discharge, Li-ion batteries only need 75 minutes. This significantly improves availability of backup power.

Another major benefit for operators that want to implement digital monitoring and control is that Li-ion batteries can be integrated with data centre infrastructure management (DCIM) and building management systems. Because they are compatible with electronic management, Li-ion batteries can be integrated with industrial communication protocols such as Modbus,OPC, TCP/IP or CANopen.

As a result, operators can monitor their battery’s state of charge (SOC), state of health (SOH), temperature and other parameters in real time. That means they can better optimise their approach to UPS design and function. 

Compact and lightweight backup for Total’s Singapore HQ

Ass an example of what is possible, French oil and gas multinational Total recently opened its new regional headquarters in Fraser Tower, Singapore. The office hosts business functions and corporate trading activities that require constant availability of power. However, Total wanted to minimise the footprint of its UPS in the high-rise building so that it could maximise the space given to other business-critical services. This was a key factor in the favour of Li-ion battery technology.

Saft provided Flex’ion battery systems with a total power capacity of 360 kW to provide backup over 10 minutes until the building’s backup generator powers up. It offers a long calendar life and inherently safe electrochemistry and construction while combining high energy density and a compact size.

Another advantage is that Flex’ion’s electronic battery management can be integrated with control and management systems, such as building management systems (BMS) and supervisory control and data acquisition (SCADA) systems. The Li-ion battery systems feature smart monitoring capability so that the company’s facility managers can monitor and analyze the condition of critical equipment. If a fault occurs, the battery monitoring system alerts the UPS maintenance provider, raising awareness of an issue before failure occurs.

TCO is key for Sparkasse banking group Germany

Another institution to benefit from Li-ion battery technology for its data centre is Sparkasse, one of Germany’s largest public banking groups, which operates data centres through its IT subsidiary. Data integrity is essential for banks to protect customers and prevent massive financial losses in the event of a power outage. When Sparkasse was delivering maintenance servives and extending a facility, it wanted high reliability and operational safety, as well as delivery within a relatively short lead time.  

Sparkasse turned to Saft and Piller Group, which worked together in partnership to design and develop a UPS package that integrated Flex’ion Li-ion battery systems with Piller’s control and conversion technology.

The partners delivered two UPS systems which are sized to supply more than 2 megawatt (MW) over 15 minutes, even after a lifetime of 15 years. Importantly, it offers inherent safety as its electrochemistry is based on Saft’s proprietary Super Lithium Iron Phosphate blend, as well as a rugged mechanical design that ensures safe containment of cells and modules.

Hot-swappable solution for industrial data centre

Total has also installed Li-ion batteries at its High Power Computing (HPC) data centre in Pau, France. The site required a high-performance UPS and battery system to protect critical information and calculations for one of the world’s most powerful industrial supercomputers. The main criteria for the UPS were low Total Cost of Ownership (TCO), innovative hot-swapability, and integration with Total’s monitoring systems. The hot-swapability enables the load to be fully protected by on-line double conversion while individual UPS or battery modules are taken out of live service for maintenance.  

The project scope also included boosting the environmental performance of the data centre through increased energy efficiency and the ability to re-inject power from the UPS into the grid or to support other loads. To meet these requirements, Saft and Socomec worked together to integrate a Flex’ion battery system into the latter’s Delphys Xtend GP uninterrupted power supply.

The partners integrated two identical UPS with Flex’ion Li-ion batteries for redundancy. The battery system is sized to deliver 550 kW for up to seven minutes within the required voltage window after an operational life of 15 years.

A program of functional testing and certification demonstrated the electrical performance of the system, including the electronic control interface between the battery and the UPS.

Big changes for UPS batteries

As data centres continue to evolve, the role and function of the UPS system is also changing. UPSs have traditionally been specified to provide up to 15 minutes of backup duration to bridge until a diesel generator can come on line. However, we’re now seeing operators specify a shorter backup duration – typically from one to 10 minutes.

Battery performance is also improving fast and this will help data centre operators get higher power out of the same footprint. Current state-of-the-art Li-ion battery systems for data centres can deliver up to 140 kW from a standard cabinet. However, improvements in Li-ion chemistry and battery design mean that we will soon see a step change to 200 kW from the same size of cabinet.

And looking further ahead to the development of a future generation of battery technology, we’re now working on research and development of solid-state batteries, which are likely to provide a power rating of 250 or 300 kW within five years.

However, for the time being, Li-ion is still the technology of choice for power density, TCO, electronic monitoring and high safety standards.