The top things to consider when looking at Lithium-Ion batteries

Critical Power 1Yes, Lithium-Ion batteries are already having an impact, but what should you be considering when looking at the battery options? Asks Martin Pearce, Critical Power.

Many aspects of technology for uninterruptible power supplies (UPS) have rapidly advanced, but one that is still firmly rooted in a traditional approach is batteries. In particular, lead acid batteries still feature as a dominant and essential part of any typical energy storage mechanic within an UPS operation. The time is ripe for all the lessons learned in other technological environments, to spill over into the critical power world.

Prime time
The desire for data, power and information is not going to disappear. In fact it is rapidly accelerating with a danger of exceeding capability. Traditional lead-acid battery options are increasingly going to struggle to meet this demand. Significant capacity, delivering substantially more energy and power is another factor. Lithium-Ion batteries are ideally positioned to cope with the rising energy requirements that many operations now expect of their battery support. The power to space ratio that these batteries provide, taking up a third or less than conventional lead-acid batteries, means a reduced UPS footprint and, importantly, weight, which in turn means spaces can be used more effectively. The smaller size also translates into reduced cooling requirements, resulting in more flexibility of where to install, and also the associated costs of extensive cooling.

Reduced sensitivity
Temperature fluctuations have limited effect on Lithium-Ion battery life. They are able to withstand significantly wider temperatures ranges. There is also increased visibility, as more sophisticated battery monitoring systems mean energy storage and the battery’s health can be checked. Potentially UPS failures can be predicted this way.  Another advantage is an extensive life expectancy. The cost of battery replacement can be significantly reduced as Lithium-Ion batteries are expected to last far more than the usual 10 years. A UPS battery needs to kick in quickly and with quite some power and only really for a relatively short period of time, until the generator establishes itself. This is contrary to how many other batteries operate, which is where the right Lithium-ion battery is ideally suited to meet this instant and strong demand.

Lower total cost of ownership
Lithium-Ion batteries may initially be more expensive to purchase, but as they last almost twice as long, ultimately their pay-back is assured. As they are smaller, they save costs in terms of both the physical space they take up and their cooling requirements. However, it is important to not just consider the field life comparison, as the technology is very different. Traditional, sealed lead acid batteries require a pressure valve for releasing hydrogen gas should the gas recharging combination cycle run away with itself.

The Lithium-Ion battery
also eliminates the risk of release of COSH controlled chemicals and explosions.
Obviously being recyclable and not containing hazardous materials is important, but we need to consider the entire aspect of the Lithium-Ion battery and overall lower consumption of energy and cooling. This includes their requirement for less energy to keep them charged, plus they self-discharge at a lower rate than lead acid batteries. It is important to bear in mind, however, the need to have a battery management system, which might potentially consume an equivalent amount in terms of energy.

Data centres
With ASHRAE and other organisations recommending increasing data centre temperatures to save on cooling costs, Lithium-Ion batteries are much better suited to these warm environments than their traditional counterparts. The design of a data centre is likely to shift, as they may negate the need for separately climate controlled rooms, with them being installed alongside the UPS in the IT room. It will be interesting to see the ripple effect that the use of Lithium-Ion batteries are going to create in data centre design.