Most people know of the Lithium-ion battery technology in use mainly due to their overwhelming presence in mobile sets. Those who use uninterruptible power supplies for backing up their systems are familiar with the lead-acid cells and the newer lithium-ion cells. Another alternative technology is also coming up mainly for mission-critical facilities such as for data centers. This is the Nickel-Zinc technology, and it has better trade-offs to offer.
But the Nickel-Zinc battery technology is not new. In fact, Thomas Edison had patented it about 120 years ago. In its current avatar, the Nickel-Zinc battery offers superior performance when used in UPS backup systems. They offer better power density, are more reliable, safe, and are highly sustainable.
For instance, higher power density translates into smaller weight and size. This is the major difference between a battery providing energy and a battery providing power. In a data center, the UPS must discharge fast for a short period for maintaining operational continuity. This is what happens during brief outages, or until the backup generators spin up to take over the load. This is the most basic power battery operation, where the battery must deliver a high rate of discharge, and it does so with a small footprint.
On the other hand, Lead-acid and Lithium-ion technologies offer energy batteries. Their design allows them to discharge energy at a lower rate for longer periods. Electric vehicles utilize this feature, and the automotive industry is spending top dollars for increasing the energy density of such EV batteries so that the user can get more mileage or range from their vehicles. This is not very useful for data center backup, as the battery must have a higher energy storage footprint for supporting short duration high power output requirements.
This is where the Nickel-Zinc battery technology comes in. With an energy density nearly twice that of a Lead-acid battery, Nickel-Zinc batteries take up only half the space. Not only is the footprint reduced by half, but the weight also reduces by half for the same power output. As compared to Lithium-ion batteries, Nickel-Zinc batteries not only excel in footprint reduction, but they charge at a faster rate while retaining thermal stability. This feature makes them so useful for mission-critical facility uptime.
Nickel-Zinc batteries have proven their reliability as well. They have clocked over tens of millions of operating hours for providing uninterrupted backup power in mission-critical applications. Another feature very useful for data center operations is the battery string operations of the Nickel-Zinc technology.
When a Lithium-ion or a Lead-acid battery fails, the battery acts as an open circuit, preventing other batteries in the string from transferring power. On the other hand, a weal or a failed Nickel-Zinc cell remains conductive, allowing the rest of the string to continue operations, with a lower voltage. In emergency situations, this feature of the Nickel-Zinc battery is extremely helpful, as the faulty battery replacement can proceed with no operational impact and at a low cost.
In parallel operation also, Nickel-Zinc batteries are more tolerant of string imbalances, thereby maintaining constant power output at significantly lower states of health and charge as compared to batteries of other technologies.