Safe.SIB

Brief Description

The project aims to develop and produce a safe, durable, and scalable sodium-ion battery (SIB) for stationary applications. These stationary storage systems are designed to store electricity over timeframes ranging from seconds to days. The key performance indicators (KPIs) for such systems are low costs (investment and operating), long lifetime (both cyclic and calendar), and high safety. In contrast to batteries for mobile applications, such as electric vehicles, energy density is of less importance. The characteristics of the emerging SIB technology show a very high compatibility with the required KPIs of stationary energy storage.

Within Safe.SIB, safe and durable sodium-ion batteries with a new electrolyte are being developed. For this purpose, pouch cells (5 Ah and 30 Ah) will be iteratively manufactured and characterized in terms of performance, durability, and safety in two phases. Based on the large-format pouch cells, a stationary storage system will then be designed, and a demonstrator will be built and tested.

The Project Schedule comprises six work packages:

WP 1: Optimized liquid electrolyte formulations with increased safety (FZJ/IEK-12)
The aim of this work package is to develop optimized non-flammable and non-aqueous liquid electrolyte formulations that are compatible with the anode and cathode defined in the project. The optimization includes variation of the concentration of the conducting salt, the solvent/co-solvent used (binary or ternary mixture) and the solvent fraction in the mixture, as well as the selection of suitable film-forming (SEI and CEI) and safety-relevant (flame-retardant) functional additives.

WP 2: Small-format cell production (MANUGY)
In WP2, MANUGY is developing the necessary system technology with a particular focus on the semi-assembly of the SIBs. The focus here is on the stacking technology (implemented as Z-folding), as this is regarded as key know-how for a reproducible and precise assembly of the SIB prototypes. A machine will be developed and implemented in which magazines with electrode sheets are inserted, which are then automatically assembled into a cell stack using the Z-folding process. Using existing infrastructure, the electrodes can be separated according to the magazines and then welded. To test the safe SIBs developed in this project during the development phase, the small-format pouch cells (5 Ah without electrolyte) will be made available to the project partners. WP2 also serves the (concept) development of a holistic SIB production line to prepare for the establishment of future SIB manufacturing lines. The work is supported by the development and optimization of a slot die for coating SIB electrodes (anode and cathode side), which can then be physically tested at Fraunhofer FFB.

WP 3: Large-format cell production (Fraunhofer FFB)
Within the framework of work package 3, and taking into account the requirements catalogue and the findings from small-format cell production, the following measures will be carried out:

1. Literature research, material selection and procurement

2. Recipe development and laboratory pre-tests

3. Upscaling and production of double-sided coated anodes and cathodes

4. Production of large-format multilayer pouch cells

5. EoL testing and electrochemical analysis

WP 4: Safety tests (ICT)
In WP4, the safety of the safe electrolyte developed in WP1 and the small-format pouch cells (5 Ah) produced from it in WP2 will be tested, and their key figures provided for the design of the large-format pouch cell (WP3) and prototype production (WP5), as well as the safety of these cells assessed. The safety tests carried out in WP1 at the electrolyte and laboratory cell level will serve as the basis. The test protocols will be coordinated with all partners in order to be able to design a safe storage system.

WP 5: Prototype production (IPT, Voltfang GmbH)
WP5 fulfills two essential functions within the project. On the one hand, the current requirements according to the applicable standards and regulations for stationary energy storage systems are to be taken into account. This is crucial to also support the project’s aim of a safe Na-ion-based storage solution from a regulatory perspective. In addition, WP5 aims to advance the development of a stationary storage system based on the Fraunhofer FFB’s pouch cells. With this approach, functional prototypes are to be designed and built that can demonstrate the efficiency and performance of the system.

WP 6: Project management (Fraunhofer FFB)
Project management is a work package that extends over the entire duration of the project. It includes administrative tasks for coordinating all project activities, schedule control, report management, risk management, and financial controlling.

The planned project will provide important insights into the processing of novel materials. The focus is not only on the active materials used for the anode and cathode, but also on the individual components of the liquid electrolyte. By using flame-retardant additives as well as additives for stabilizing the SEI and CEI, a new electrolyte system will be developed, enabling all participants to expand their technological understanding. The data generated during the development and production of sodium-ion batteries are not available to this extent and are of immense importance for future advancements.

Furthermore, all project partners will be informed and made aware of the key aspects involved in building a stationary storage system, allowing them to address future tasks related to stationary storage more quickly and effectively. In this way, the project enhances expertise in the fields of sodium-ion batteries, electrolyte development, and stationary energy storage. Indirectly, individuals not directly involved in the project will also be reached through presentations given by the participants, thereby raising awareness of these topics. As a result, the consortium partners will become recognized expert contacts for potential future projects.