Periodic Reporting for period 2 - COBRA (CObalt-free Batteries for FutuRe Automotive Applications)
Periodo di rendicontazione: 2021-05-01 al 2022-09-30
COBRA addresses the main shortcomings of xEV batteries that are now in the market by enhancing each component in the system holistically. The COBRA battery cells will be fabricated using electrodes containing no cobalt without compromising capacity and nominal voltage. The new components will allow rapid cell charging and enhanced safety at a reduced cost. At cell level, the main target is to maximize energy density and integrate smart sensors to improve safety. The battery pack will be constructed using sustainable and recycled materials, and the advanced BMS will ensure optimum battery performance and an extended lifetime for the system. The COBRA project will allow the development of European technology for generation 3b of Li-ion batteries, with an improved performance (electrochemical, economic, and environmental) that could be exploited at an industrial scale shortly after the project’s completion. The COBRA project is important for society in many aspects, including 1) decarbonizing road transport, 2) the production of innovative and sustainable materials and processes for battery production that can be easily adapted to production lines, 3) the reduction of CRM, especially Co, to improve aspects related to energy security, “conflict mineral” vs “ethical supply chain”, and toxicity associated to current Li-ion batteries, 4) reduce dependency on foreign suppliers 5) validate a cost-effective and sustainable technology for the end-user and 6) fulfill energy and power demands associated to xEV of the near future. Regarding COBRA objectives, COBRA will develop a Co-free Li-ion battery technology, demonstrate it at TRL6 (battery pack), and validate it on an automotive EV testbed. At the component level, the main objectives are as follows: a) high discharge capacity and fast C-rate discharge capacity for the cathode, b) useful cycle life of 2000 cycles and withstand high C-rates for the anode, c) stable electrolyte operation at > 4.5 V, d) energy density of at least 750 Wh/l at cell level, e) develop an advanced BMS including smart sensors, f) a more sustainable battery pack with improved characteristics, g) testing and validation of the battery pack for xEV applications and h) attain >95% recyclability of metals at large scale and avoid the use of Co by 100%.
GEN1 and GEN2 Li-rich oxide materials have been synthesized, and their structure and electrochemical performance evaluated to select the best candidates for GENX. Al0.01 GEN1 composition delivers a high discharge capacity ˃ 200 mAhg-1 with a capacity retention of 88.5% after 100 cycles. Cathode water processing afforded comparable results to NMP-based processing. Silicon samples have been recycled from different sources and tested electrochemically as active material in composite anode using graphite. The best-performing anode delivers a high discharge capacity of 650 mAhg-1 at C/3 and 438 mAhg-1 at 3C. In the frame of WP3, several electrolyte compositions were formulated and tested: salts were formulated in carbonate-based solvents or as ionic liquids and new additives, including flame-retardant ones, were also considered. For specific compositions, a polymer electrolyte has been fabricated, but its performance requires further optimization. Certain ionic liquids show promising results for full cells charged up to 4.7 V. Full cell cycling has been conducted for GEN1 and GEN2 as a function of voltage window and cell formation protocol to define pouch cell specifications. GEN1 and GEN2 pouch cells were delivered to partners for characterization. For GEN2, tests include ageing and safety. Regarding WP5, the testing activities for the smart sensor integration (strain, EIS) at the cell level have been accomplished, and the optical link communication system has been prototyped and validated at the module level. The advanced models and control algorithms for the new, innovative BMS, are progressing adequately. The MCU has been finalized while the BCU’s integrated application software’s interfaces have been aligned, and a new SW architecture for the software has been designed. The GEN0 battery pack was assembled and commissioned. The battery pack fabrication included light and strong components with recycled materials, and its design targets easy battery disassembly for 2nd life. For the validation of the battery packs (GEN0 and GENX), testing activities have been defined with the market needs and the current regulations. GEN0 battery packs have been tested and validated. Regarding life cycle assessment, the work carried out is centered in analyzing the components and processes used to manufacture GEN1 cells which will be extended to GENX cells eventually. The work on dissemination is focused on communicating project results and advances through social media and online events, together with the development of a website and the distribution of newsletters. An exploratory process to identify the main project outputs for commercialization was started. IREC has been monitoring the project activities and work progress. Additionally, all the management of financial and administrative activities necessary for the success of the project have been carried out.
Co-free oxide materials with a composite (R+M) structure have been prepared and tested as cathodes for generation 3b batteries. These materials are less toxic and less expensive than current cathode materials e.g. NMC622 or next-generation NMC811, since COBRA materials do not contain cobalt. Green GEN2 pouch cells were fabricated using water as the solvent for both the cathode and anode. The cathode, together and a selected electrolyte, can be cycled up to 4.7 V delivering a stable capacity at a laboratory scale. The anode composite fabricated using silicon obtained from recycling e.g. kerf from the photovoltaic industry, shows promising electrochemical results, and to our knowledge, no recycled material has been reported as an anode before. The anode delivers high capacity at a 3C rate allowing fast charging for the battery cell. Best-performing electrolyte compositions and new additives to improve safety have been characterized at the coin cell level. Some selected compositions, including ionic liquids, have been selected for polymer engineering, which will enhance the cell energy density and safety of battery cells and facilitate the transition towards solid-state battery cells (generation 4). The COBRA project will deliver a battery cell with electrochemical performance in the range of state-of-art Li-ion battery cells but without cobalt. The project aims to fulfil the cycle life target of 2000 cycles and 2.5C rapid charging to accelerate the implementation of generation 3b battery systems. The assembly of large 30 Ah pouch cells suitable for automotive applications will be conducted in a semi-automatic assembly line that will allow rapid integration and high flexibility for the manufacturing processes, including integrating smart sensors at the battery cell level. The battery pack is designed with innovative materials that reduce the environmental impact and the system’s weight while increasing its safety and fire resistance, and strength. Moreover, the gas sensor will be placed at pack level to monitor and prevent safety risks. The advanced BMS will centralize the control and safety of the battery and enhance its electrochemical performance.