Periodic Reporting for period 1 - greenSPEED (Green and Sustainable Processes for Electrode Production)
Berichtszeitraum: 2022-07-01 bis 2023-12-31
Lithium-ion technology is the means to greener and more sustainable mobility and other mobile applications. Unfortunately, the process of cell manufacturing is still energy consuming and is using environmentally harmful substances. The greenSPEED project offers solutions for new sustainable electrode and cell manufacturing processes with reduced energy consumption, lower carbon footprint and ZERO Volatile Organic Compounds (VOCs) emissions.
Introducing the dry electrode production technique for the cathode in greenSPEED, the use of organic casting-solvents such as NMP as slurry dispersing media is completely eliminated. This enables to avoid large capital investment costs associated to casting-solvent recovery systems.
Further, a special method enables a solvent free anode processing technique. During this process, silicon will be deposited on optimised copper foil. No binders and no conductive agents are required which leads to work on pure silicon anode with less cost and energy consuming fabrication. greenSPEED will replace conventional graphite with this type of anode.
Three main objectives (O) are set:
O1: Develop electrode and cell manufacturing techniques, enable European leadership
O2: Low cost and environment friendly electrode coating production techniques for increased efficiency and better cycle life
O3: Digital twin for production processes, industrialising closed loops and sustainable process design to reduce mining efforts
Introducing the dry electrode production technique for the cathode in greenSPEED, the use of organic casting-solvents such as NMP as slurry dispersing media is completely eliminated. This enables to avoid large capital investment costs associated to casting-solvent recovery systems.
Further, a special method enables a solvent free anode processing technique. During this process, silicon will be deposited on optimised copper foil. No binders and no conductive agents are required which leads to work on pure silicon anode with less cost and energy consuming fabrication. greenSPEED will replace conventional graphite with this type of anode.
Three main objectives (O) are set:
O1: Develop electrode and cell manufacturing techniques, enable European leadership
O2: Low cost and environment friendly electrode coating production techniques for increased efficiency and better cycle life
O3: Digital twin for production processes, industrialising closed loops and sustainable process design to reduce mining efforts
WP1 Requirements: The high level industrial and automotive cell requirements for the project-cell have been defined. Following this task, the validation- and test-protocols for the project cell in respect of calendar, cycle-life, performance and safety behavior have been defined and documented.
WP2 Anode: One approach is to increase the specific capacity of the negative active material. This can be achieved by introducing Silicon (Si) into the anode. In general, in greenSPEED two different types of anodes are developed: 1) Water-based Si/C composite electrode 2) direct deposition of Si on the current collector via microwave plasma enhanced chemical vapor deposition.
Both types of anode parameters are optimized according to cell lifetime, homogeneity, porosity, performance, etc. In addition, studies were carried out to evaluate the properties for pre-lithiation as an input for a decision on which setup to pick for the further project work towards the final greenSPEED cell generation.
WP3 Cathode: The binders and the foils have been characterized with a particular focus on properties regarding their behaviour in processing. Especially, the interaction of different foil types with different grades of binder was investigated. As the most relevant parameter, adhesion was analysed for wet processing as a reference and – along with the development of new methods – for dry preparation in comparison.
All data collected in the different process steps and machines can now be transferred to the cloud. First algorithms are established that convert this data to a ML-ready form. This was already successfully tested for the extruder data.
Regarding the roll-to-roll transfer process of the flat composite film onto the current collector, adhesion turned out to be the most relevant issue. As a result, the content of EC can be reduced only slightly and is accompanied by an increase of the minimum possible mass loading. As a more promising approach, future work will focus on the use of customized binders and aluminium foils.
WP4 Cell: Different generation of cells have been defined, whereas the baseline chemistry for the greenSPEED has been tested in laboratory format cells. First tests with stacked pouch cells have been started. A state-of-the-art (SotA) electrolyte has been used as baseline. Furthermore, varying the electrolyte content and additives has been tested in half- and full cells. The greenSPEED Gen1 cells have been studied in small scale cells- varying the Si content from 70-80%. The variation on electrolyte has shown significant influence on performance of the cell, as well the binder content and changing the parameters of the copper foil. The pure Si anode is firstly demonstrated on lab cell level and results in a good performance but a low cycle life. Furthermore, the pure Si anode has been investigated by varying the applied pressure and the breathing and swelling of the cell during formation and cycling.
WP5 Modelling: Cell component tests have been conducted, especially tensile tests for the current collectors. The procedure of evaluating the test data and validating the material models has been established and will be used for the future pending tests. A meso-mechanical cell model for the bi-layer pouch has been set up resembling the full layer structure of the cell. Python scripts have been written for a fast adaptation of the mesh. Material models were parameterised, validated, and implemented using already available data from greenSPEED materials. The first iteration of simulations has been performed comprising a cell compression step and cell charging using an expansion model for the anode.
The enhancement of a physical equivalent circuit model by AI methods is currently investigated.
WP6: greenSPEED cost engineers have started to prepare cost and CO2e models in the software as a preparation step for the partner alignments. Input templates regarding Cost and Sustainability assessment were sent out to the consortium members.
WP7: The greenSPEED management quality process is implemented, and social media presence is established. An initial data management plan is developed and interfaces to the project environment (BEPA and LiPLANET associations and advisory board) are established.
WP2 Anode: One approach is to increase the specific capacity of the negative active material. This can be achieved by introducing Silicon (Si) into the anode. In general, in greenSPEED two different types of anodes are developed: 1) Water-based Si/C composite electrode 2) direct deposition of Si on the current collector via microwave plasma enhanced chemical vapor deposition.
Both types of anode parameters are optimized according to cell lifetime, homogeneity, porosity, performance, etc. In addition, studies were carried out to evaluate the properties for pre-lithiation as an input for a decision on which setup to pick for the further project work towards the final greenSPEED cell generation.
WP3 Cathode: The binders and the foils have been characterized with a particular focus on properties regarding their behaviour in processing. Especially, the interaction of different foil types with different grades of binder was investigated. As the most relevant parameter, adhesion was analysed for wet processing as a reference and – along with the development of new methods – for dry preparation in comparison.
All data collected in the different process steps and machines can now be transferred to the cloud. First algorithms are established that convert this data to a ML-ready form. This was already successfully tested for the extruder data.
Regarding the roll-to-roll transfer process of the flat composite film onto the current collector, adhesion turned out to be the most relevant issue. As a result, the content of EC can be reduced only slightly and is accompanied by an increase of the minimum possible mass loading. As a more promising approach, future work will focus on the use of customized binders and aluminium foils.
WP4 Cell: Different generation of cells have been defined, whereas the baseline chemistry for the greenSPEED has been tested in laboratory format cells. First tests with stacked pouch cells have been started. A state-of-the-art (SotA) electrolyte has been used as baseline. Furthermore, varying the electrolyte content and additives has been tested in half- and full cells. The greenSPEED Gen1 cells have been studied in small scale cells- varying the Si content from 70-80%. The variation on electrolyte has shown significant influence on performance of the cell, as well the binder content and changing the parameters of the copper foil. The pure Si anode is firstly demonstrated on lab cell level and results in a good performance but a low cycle life. Furthermore, the pure Si anode has been investigated by varying the applied pressure and the breathing and swelling of the cell during formation and cycling.
WP5 Modelling: Cell component tests have been conducted, especially tensile tests for the current collectors. The procedure of evaluating the test data and validating the material models has been established and will be used for the future pending tests. A meso-mechanical cell model for the bi-layer pouch has been set up resembling the full layer structure of the cell. Python scripts have been written for a fast adaptation of the mesh. Material models were parameterised, validated, and implemented using already available data from greenSPEED materials. The first iteration of simulations has been performed comprising a cell compression step and cell charging using an expansion model for the anode.
The enhancement of a physical equivalent circuit model by AI methods is currently investigated.
WP6: greenSPEED cost engineers have started to prepare cost and CO2e models in the software as a preparation step for the partner alignments. Input templates regarding Cost and Sustainability assessment were sent out to the consortium members.
WP7: The greenSPEED management quality process is implemented, and social media presence is established. An initial data management plan is developed and interfaces to the project environment (BEPA and LiPLANET associations and advisory board) are established.
The beyond state-of-the-art results within greenSPEED are described as follows:
- Implementation of a chemically self-anchoring cathode binder in combination with an activated aluminium surface without the use of a thin primer layer.
- Implementation of a mechanically self-anchoring copper surface for pure silicon anodes which sustains the large volume expansion of silicon.
- Development of accelerated gassing tests for stacked pouch cells to evaluate possible side reactions of the used materials.
- Successful precharging and prelithiation of all-silicon electrode for improved lifetime and energy density.
- Industrialization of precharged electrodes.
- A meso-mechanical model for estimating the consequences of cell compression in combination with cell expansion for various boundary conditions and one for the simulation of the rolling process for cylindrical cells and the assessment of different production related parameters on the stresses in the jelly roll.
- Implementation of a chemically self-anchoring cathode binder in combination with an activated aluminium surface without the use of a thin primer layer.
- Implementation of a mechanically self-anchoring copper surface for pure silicon anodes which sustains the large volume expansion of silicon.
- Development of accelerated gassing tests for stacked pouch cells to evaluate possible side reactions of the used materials.
- Successful precharging and prelithiation of all-silicon electrode for improved lifetime and energy density.
- Industrialization of precharged electrodes.
- A meso-mechanical model for estimating the consequences of cell compression in combination with cell expansion for various boundary conditions and one for the simulation of the rolling process for cylindrical cells and the assessment of different production related parameters on the stresses in the jelly roll.