Over the years, technological advancements have led to the latest generation of Centiel UPS systems achieving approximately 97% efficiency. However, we have been using the same lead-acid or VRLA batteries for the backup energy storage of UPS systems for about 30 years! They still do their job, and they do it well, so why should we change this?
The challenge with VRLA batteries is that they still require a temperature of about 20 °C to optimize their lifespan. An industry-standard estimate is that for every 10 degrees above 20 °C, the lifespan of a VRLA battery is halved. For this reason, in relation to energy management, active efforts are being made to find alternatives.
Li-ion batteries offer an alternative to VRLA because they can operate smoothly at much higher temperatures, up to the high twenties/low thirties degrees Celsius. Most IT systems also function well at >25 °C, and UPS technology itself can work effectively up to 40 °C. Especially in many European countries, this could mean that the natural air temperature (which averages between 20-22 °C) could eliminate the need for air conditioning entirely. This would result in significant cost savings for data centers and a reduced carbon footprint.
Space-saving is also a potential advantage. Many data centers have sufficient space to accommodate lead-acid batteries without any issues. However, in cases where space is limited, Li-ion batteries typically require one-third of the physical space of equivalent VRLA blocks and are less than a quarter of the weight. These space-saving features can benefit smaller regional and edge data centers, for example, and allow for more rack space in a smaller technical room.
Up until now, a drawback of switching to Li-ion has been the higher upfront costs. However, prices have fallen in recent years, and the difference with VRLA has become considerably smaller. In general, the initial CAPEX costs of purchasing Li-ion batteries are typically up to twice as expensive as lead-acid batteries. However, Li-ion lasts twice as long. Lead-acid batteries with a design lifespan of 10/12 years are usually replaced after seven or eight years. With Li-ion, this is extended to 13-15 years. When considering this factor alongside the overall energy savings, Li-ion can reduce the total cost of ownership (TCO).
In the past, safety concerns related to Li-ion batteries have been raised. Nevertheless, technology has advanced. The management and testing of Li-ion batteries fall under the IEC62619 standard introduced internationally over two years ago, specifically addressing control systems in industrial batteries. Li-ion batteries are more sensitive to how they are charged and discharged, as some Li-ion materials release O2 at high temperatures during overload conditions or thermal runaway. Hence, the IEC62619 regulation mandates having an internal battery management system (BMS). This prevents the organic liquid electrolyte from becoming too hot due to overcharging or undercharging. The BMS issues a warning when the safe voltage range is exceeded, and the compatible UPS can respond. If this is ignored, a level-two alarm is triggered, associated with a circuit breaker to prevent further cell charging or discharging. This double protection level must be implemented and tested to comply with the IEC62619 regulation.
Every battery, including lead-acid batteries, has the potential for danger, but when managed correctly, Li-ion technology has now been developed to be safe for use in data centers and other facilities requiring critical power protection.
There are various types of Li-ion battery materials available; NCM, LCO, LMO, and LFP are the most commonly used. A material with high stability in all conditions is required. The safest and most reliable is LFP because the decomposition of LFP does not generate O2, which significantly reduces the risk of explosions.
In the very near future, the acceptance of Li-ion in the UPS industry will undoubtedly increase. However, systems must be Li-ion-ready, and UPS equipment manufacturers must ensure that their technology is compatible and can communicate with the Li-ion battery monitoring system.
Interestingly, the adoption of Li-ion within UPS systems has been greater so far in developing countries such as Africa and the Middle East, where the main power grid is less reliable than in, for example, the United Kingdom, and frequent power issues are more common. In these cases, UPS and battery systems need to be triggered multiple times a day. This higher adoption is mainly due to the longer lifespan of Li-ion: usually 3,000 power-up and down cycles compared to about 300 for VRLA technology.
This could indicate another application for Li-ion. With the increasing pressure on the energy supply of our cities, demand-side energy management could lead data centers to be paid for their excess energy. Stored energy can be fed back into the grid during downtime and the UPS can act as a hub, generating revenue by taking advantage of the demand for and use of power. The properties of Li-ion batteries allow for interesting alternative uses.
Centiel's Li-ion solution is already being installed by our most progressive customers who want to benefit from Li-ion's advantages over lead-acid batteries, such as being smaller, lighter, having high power density, a longer lifespan, and operating at higher temperatures. In the next five years, we expect a significant industrial shift to Li-ion. The good news is that CENTIEL's technology is already Li-ion-ready. Existing lead-acid battery installations have the potential to upgrade to Li-ion in the future without having to replace the UPS.
Looking for more information about Li-ion batteries? We are here to help! Send an email to info@elinex.com or call one of our power backup specialists at +31 180-415711.
Text: Gerado Lecuona, Co-founder and Global Sales Director, CENTIEL SA
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