A significant focus of the eCAIMAN project is on the development of active materials for an automotive cell, i.e. active materials for cathode and anode, and a corresponding compatible electrolyte. Extensive cell engineering to harmonize compatibility of the developed active materials with the needed inactive materials in the cell, such as separators, binders, current collectors, etc., is also undertaken.
For the cathode, eCAIMAN worked with LNMO (LiNi0.5Mn1.5O4). Different synthesis approaches to producing the spinel were pursued in parallel by three partners in the consortium. Structural modifications to the spinel, such as doping and substitution strategies, were also investigated to optimize the performance of the synthesized LNMOs. Finally, surface treatments of the spinel were applied to reduce undesirable reactions between the active material and the electrolyte. The most promising LNMOs were selected and subjected to performance testing, and finally the best-performing, an Al-doped and an Fe-doped LNMO, were scaled up to pilot scale (~1kg each). Since the module demonstrator in the project requires a larger number of cells, commercial LNMO was purchased and the parameters for cell harmonization were determined. One hundred pouch cells were produced with the commercial LNMO for use in the demonstrator modules.
For the anode, two generations of modified synthetic carbons as active material were developed. The second generation was selected for further use in the cells developed in the project. An investigation on partial replacement of carbon by tin dioxide (SnO2) was undertaken utilizing different techniques. SnO2 particles -pure and doped- were synthesized. The possibility of enhancing SnO2 performance via a surface modification leading to better SEI properties was also explored (SnO2+g-C3N4).
For the electrolyte, a reference generation was used as a baseline. The initial gas formation and attendant cell swelling could be overcome with the next iteration of the electrolyte, “eCAIMAN1”. This led to significantly reduced swelling as compared to the baseline electrolyte, and enabled the assembly of a set of cells with commercial LNMO cathode, graphite anode and eCAIMAN1 electrolyte developed in the project.
To investigate the integration of the cells into two-wheelers, cars and trucks, the technical requirements of the three vehicle OEMs participating in the project were harmonized. This enabled the design of a flexible module that is suitable for all three vehicle classes. The battery management system was updated to enable operation with high-voltage cells.
The developed cells were subjected to out-of-operation/abuse testing to determine their safety, and the power electronics (BMS) were examined from a safety perspective as well.
In cooperation with two other projects funded under the same call (SPICY and FIVEVB), eCAIMAN issued a white paper with harmonized recommendations on cell testing for this new generation of high energy/high voltage cells. The findings are intended for uptake by standardization bodies, and this is promoted by the members of the project consortia active in these bodies.
