Investigation of Fe-Ni Battery/Module for Grid Service Duty Cycles.

Area of Science:

• Electrochemistry
• Energy Storage Systems
• Materials Science

Background:

• Iron-nickel (Fe-Ni) batteries offer durability but face adoption hurdles due to low efficiency and high maintenance costs.
• Grid energy storage demands reliable and efficient battery technologies for applications like frequency regulation and peak shaving.

Purpose of the Study:

• To evaluate the feasibility and performance of Fe-Ni batteries in grid energy storage applications.
• To assess the impact of state of charge (SOC) on Fe-Ni battery efficiency and cyclability for grid services.

Main Methods:

• Frequency regulation (FR) testing at various states of charge (100%, 50%, 25%).
• Peak shaving (PS) testing under diverse load conditions.
• Extended cycling tests to evaluate long-term stability and reliability.

Main Results:

• Stable performance observed during FR testing at 100% and 50% SOC, with a 14% efficiency increase at 50% SOC compared to 100% SOC.
• Higher efficiency at 25% SOC was noted, but limited cyclability was observed due to discharge cutoff voltage.
• Fe-Ni batteries demonstrated stable results in PS testing and potential for long-term grid-scale applications through extended cycling.

Conclusions:

• Optimal SOC selection, battery monitoring, maintenance, and charging strategies are critical for effective FR applications of Fe-Ni batteries.
• Fe-Ni batteries show suitability and reliability for peak shaving applications.
• The study confirms the potential of Fe-Ni batteries for long-term grid-scale energy storage, particularly for FR and PS services.