Periodic Reporting for period 2 - SOLiDIFY (Liquid-Processed Solid-State Li-metal Battery: development of upscale materials, processes and architectures)
Reporting period: 2021-07-01 to 2022-12-31
The main objectives described in the project proposal are still accurate and extremely challenging as described below:
Today’s electric vehicles are equipped with lithium-ion battery cells that can deliver a little less than 700 Wh/L (230 Wh/kg) and thus a significant boost in performances is still needed while safety of the cells should remain ensured. A range of 700 km is considered a turning point in consumer interest. To reach this driving range, cells of > 900 Wh/L (> 500Wh/kg) will be needed. SOLiDIFY plans to demonstrate two generations of solid-state battery cells reaching 900 Wh/L and 1200 Wh/L, respectively.
In terms of charging time, customers expect to be able to recharge partially their battery in less than 20 minutes, which we set as a target to recharge our solid-state battery cells.
Finally, while current Li-ion battery cell cost is nowadays on average > 125 €/kWh, it is a project objective to achieve a manufacturing and material strategy to reach the cost target of < 100 €/kWh. Overall, the project comprises the development of a manufacturable solid-state battery technology based on a unique liquid-to-solid processed solid electrolyte which is easily impregnated into the electrodes providing multiple advantages towards cell performance and upscale manufacturing both directly in relation with the cost of the cell (€/kWh). The wider scope of the SOLiDIFY project entails the development of a novel and potentially European-lead solid-state battery technology and specifically targets upscaling of the processes and cells from demonstrated concepts in the lab to prototypes demonstrated in a pilot line environment.
Over the last 18 months, the different key components towards Gen S2 demonstrators have been developed, characterised, and assessed separately:
i) advanced cathode architectures (open current collector, single-step and trenched) incorporating NMC622 and NMC811 positive electrode(s) (cathode) consisting of these active material particles covered with a new thin coating and deposited on a current collector made of a thin (10 µm) aluminum foil (Umicore, Delft-IMP, Fraunhofer, imec, TU-Delft)
ii) advanced PIL-based solid electrolyte separator sheet being mechanically stable, thin, and conducting the Li+ ion at room temperature (imec, Solvionic, Empa), which can also be infiltrated into NMC cathodes. The addition of additives (imec) has been evaluated, further improving the mechanical strength and ionic conductivity and allowing the attainment of 100% areal capacity of partner cathodes (NMC622@TiO2).
iii) new group of advanced negative electrode(s) (anode) consisting of protected thin Lithium metal anode (Sidrabe, EMPA, imec, TU-delft) based on nitrification and PIL coatings on 20 µm Li metal on 10 µm Cu foils.
In addition, initial integration works have taken place under the coordination of imec and Fraunhofer, with the first Gen S1 (3×5) cm2 pouch cell assembled and upscaled components received ready for integration into (10×15) cm2 pouch cells at Fraunhofer.
A new cell was specifically designed by UHasselt to test solid-state battery cell and component performance as a function of temperature and pressure. Initial results on the newly developed solid-state electrolyte membrane were collected, and now directed towards PIL-based SCEs.
In concertation with all partners, the cell specifications, requirements, and testing protocols have been developed by the cell manufacturer and equipment supplier (Leclanché, Solith) and end users (CRF, VDL), respectively. Furthermore, pouch cell process flows have been developed and adapted according to the handling and requirements of the developed components, and communicated to all concerned partners. In parallel, the preparation work for the Life Cycle Analysis and cost analysis of new solid-state battery cell started (Gemmate, Leclanché), with requested data from all partners communicated and delivered to Gemmate for the preparation of the LCA for Gen S1 demonstrators.
Advanced materials and assembly processes have been, and continue to be, developed and (some) protected as patent applications to strengthen the patent portfolio of the partners and their position in the market. Such advancements are identified as key exploitable results (KER), which have recently been reviewed and consolidated into 20 KERs.
New models, methodologies and analysis techniques specific for Solid State Battery have been developed as part of the project and will contribute to strengthen the expertise of the partners, strengthening longer-term capabilities and thus fueling the EU modeling ecosystem. In parallel, SOLiDIFY developments will be conducted with full Life Cycle Analysis to ensure that a positive environmental impact is achieved with the developed technologies and materials. Environmental impact assessment of the full life cycle including recycling started, and is ongoing. Beside contributing to the preservation of the environment, the SOLiDIFY projects’ vision is to contribute to the European society via the strengthening of the European battery value chain through the development of a competitive and sustainable battery cell in Europe. In addition, the project aims to enable the development, in Europe, of a gender-diverse, highly qualified work force skilled in the latest battery materials and technologies.