Philosophiae Doctor - PhD / Energy storage systems represent a viable option to integrate renewable energy sources into the grid network. Multiple energy storage technologies are available such as mechanical, electrical, thermal, and electrochemical storage technologies. Battery Energy Storage Systems are considered as an accepted solution for energy storage with advantages such as, sustained power delivery, geographical independence and, fast response capability. This thesis describes the development of rechargeable bipolar Nickel-Iron batteries as potential candidates for cost effective energy storage solutions. The first objective of this work was to design a bipolar electrode comprising an Iron (Fe)-based anode, a Nickel (Ni)-based cathode and a flexible bipolar plate and to optimise its production process in order to attain high performance in terms of capacity and efficiency. Research questions to be answered included;