The WinZIB project delivers a modular zinc‑manganese battery system that can be stacked into multi‑kilowatt‑hour units for photovoltaic storage. Each base module holds roughly 1 kWh (84 Ah) and contains six cells in series, each about 2 V. Modules are electrically connected in series to form stacks, and each stack is managed by a dedicated control box that integrates battery‑management functions. The system can be paired with a range of DC‑coupled inverters, allowing flexible AC‑output power from 5 kW to 10 kW. In the reference comparison the WinZIB system uses a 5 kW inverter for the SubSahara off‑grid scenario and a 10 kW inverter for the on‑grid scenario, whereas the reference system employs two 5 kW inverters and a 10 kW PV array. The usable capacity of the WinZIB stack is 8.1 kWh in the off‑grid case and 10 kWh in the on‑grid case, meeting a 99.7 % reliability target without exceeding the required energy demand. The system efficiency ranges from 70 % to 76 %, with a C‑rate of 1 h for both charge and discharge. Long‑term cycling tests show more than 100 cycles with a state‑of‑health decline that matches literature values for similar chemistries. The projected lifetime of 10 years is achieved without the need for component replacement, provided the usable capacity remains above 8 kWh after a decade.

Cost analysis demonstrates a dramatic reduction compared to a conventional lithium‑ion reference. The battery part cost of the WinZIB stack is 33.4 €/kWh usable, versus 30.8 €/kWh for the reference, yielding a 91 % savings in the battery module. The overall system cost is 107 €/kWh usable compared with 91 €/kWh for the reference, a 76 % to 78 % total savings. The levelised cost of storage (LCOS) falls to 9–13 ct/kWh, a 66 % to 72 % reduction, while the levelised cost of electricity (LCOE) drops by 47 % to 41 %. In the German SPI scenario a 30 kWh usable capacity could further lower LCOS and LCOE by 2 ct/kWh each, although the higher capital cost would conflict with competition criteria. The system’s safety profile is enhanced by the use of abundant zinc and manganese, avoiding hazardous lead or toxic lithium compounds, and the modular design allows for straightforward maintenance and scalability.

The project was conducted under the German Pilot Innovation Competition “Weltspeicher”, targeting a globally deployable storage solution. Key partners include Fraunhofer institutes, which performed extensive patent searches and provided technical expertise; BYD Co. Ltd. and Pylon Tech Co. Ltd., whose modular stack designs were evaluated for freedom‑to‑operate; and several industrial collaborators who will establish large‑scale production lines. The consortium’s roles span chemistry development, system integration, performance testing, and market analysis. The competition framework set a deadline in 2024, with the project’s milestones aligned to deliver a prototype, conduct field trials, and prepare a commercial roadmap. Funding was provided through the competition’s grant mechanism, and the project’s outcomes are intended to support the transition to renewable energy in both developed and developing regions by offering a cost‑effective, safe, and scalable storage alternative to lithium‑ion and lead‑acid batteries.