The Runaway Review

Join Product Manager, JJ Hocken, as he reviews batteries and discusses the advantages and disadvantages of various chemistries impacting the UPS industry.

The Runaway Review

Join Product Manager, JJ Hocken, as he reviews batteries and discusses the advantages and disadvantages of various chemistries impacting the UPS industry.

Nickel Zinc

FEBRUARY 21, 2023


by J.J. Hocken, Product Manager Batteries & DC Technologies

Nickel-Zinc (NiZn) chemistry and technology has been around since 1901 when Thomas Edison patented the first rechargeable nickel-zinc battery system. Early battery designs had short cycle constraints typically brought on by dendrite formation and zinc migration in the battery cells. Cell dry out was also a common issue in early Nickel-Zinc battery design; however, the design has greatly advanced since the early 1900s.


The use of nickel hydroxide anode and zinc oxide cathode with a proprietary brand electrolyte has advanced the use of Nickel-Zinc batteries in many designs, including Uninterruptible Power Supply (UPS) systems. Different battery manufacturers may use a proprietary blend of electrolyte, but the most common chemical makeup would be potassium hydroxide (KOH).


The modern advancements in design and the ability to mass produce the battery has greatly improved the economics and commercial viability of the battery chemistry. Both nickel and zinc have low toxicity and are economically viable materials to source both domestically in the USA and abroad. 

Advantages of the NiZn battery chemistry in the UPS industry


Reduction in logistics and supply chain complexity due to reduced sourcing costs and domestic availability of non-hazardous materials



Very low risk of fire propagation and no risk of thermal runaway 



Longer life (typically a 15-year design lifespan depending on battery design)



Extended cycle life depending on use case and depth of discharge can be 600 cycles to 1500 cycles. This also depends on brand and design. Generally, NiZn batteries have a relatively long cycle life.  



Extended operating temperature profile typically 0°C to 35°C depending on battery brand. Degradation or deratings may apply while operating in this temperature range. 



Low internal resistance while retaining thermal stability



Can include a 10-year warranty depending on manufacturer



Smaller footprint than traditional VRLA, and in some instances, lithium ion



High favorable sustainability factors with estimated reduced carbon payback times and significant Green House Gas (GHG) emission savings



High recyclability and payback as Nickel and Zinc are easy to recycle



Favorable UL9540A test results for most known NiZn brands



Design driven safety: stable chemistry, no thermal runaway risk, and if needed, can be extinguished with carbon dioxide, dry chemical, or foam extinguishers


Disadvantages of the NiZn battery chemistry in the UPS industry



Potentially greater CAPEX pricing and cost per kWh than LMO/NMC lithium ion battery chemistries (dependent on manufacturer and system design parameters)



New technology which brings new challenges, long-term unknowns, and possible new service requirements to the UPS system market



Possible cool down period after 100% discharge before recharging (dependent on manufacturer, design, and exact chemistry of the NiZn batteries)


Depending on the manufacturer, the CAPEX cost of NiZn may be high at first, but the overall Total Cost of Ownership (TCO) can be attractive to many potential clients. NiZn is a sound choice if a client prioritizes TCO and not purely CAPEX costs. With environmental concerns taking center stage lately, the high sustainability and recycling factors of NiZn are often key drivers for clients.


Additionally, the safety factors of NiZn should not be overlooked, especially with new regulations and tighter restrictions from local AHJs. The current data suggests that NiZn batteries have no thermal runaway risk and possess a high fire safety rating, making these batteries a safer alternative to both Pure Lead VRLA and lithium ion batteries. NiZn may be a solid choice for an energy dense battery in data center and colocation applications for diversification.


However, NiZn is a new technology for UPS applications and does present unknowns.

Edited by Nicole Kristof, Digital Marketing Specialist and MarySandra Do, Content Marketing Specialist

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