MAT4BAT Advanced materials for batteries Summer School June 2-4 th 2015 «Electrode formulation and processing» Dane Sotta (CEA-Liten, France) Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 1
Outline Introduction: CEA Battery Platform Electrode manufacturing: Description of main operations Focus on water-based electrode manufacturing Issues associated with water-based cathodes + LTO Results from Elibama FP7 project Results from Mat4Bat FP7 project Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 2
CEA Battery platform Presentation From lab-scale developments to technology transfer From material synthesis to pack integration and monitoring 40 M investment 200 technical experts 3000 m² including 1000 m² dry rooms 30+ industrial partners including Renault Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 3
CEA Battery platform Lithium-ion cell manufacturing : A complex process & environment Dry room 43±3 C DP ISO6 (class 1000) Materials: NMP solvent «Nano» powders (CEA specific) Electrical security (cell pack) Large scale Factories for Li-Ion Batteries, Dr. Klaus Eberhardt - M+W Group IPVEA PV Production and Battery Forum at PVSEC, Paris, 2013 Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 4
Electrode manufacturing Electrode manufacturing Materials selection, preparation and dosing Slurry preparation Electrode coating and drying Electrode calendering Electrode slitting Active material Conductor additives Polymer binders Solvent Collector foil 0,948 X_CMC 0,05 7 10 24 X_CB 0,948 39 34 22 0,000 5 47 33 40 17 45 0,000 1,00 X_Binder Materials fractions Mixing equipment Mixing sequence Dispersion time Dispersion speed Mixing T C Coating speed Dryer T C Slurry mass flow Calendering T C Applied pressure Process parameters BET surface area (m²/g) D50 (µm) Dry content (%) Tap density (g/cm 3 ) Viscosity (Pa.s) Density (g/cm 3 ) «Macro» scale parameters Electrode loading (mg/cm²) Porosity (%) Peel strength force (N/m) Flexibility Residual H 2 O (ppm) End-user spec: Voltage, Energy density, Power Capability, Cycle life «Micro» scale properties Materials interactions, microstructures, (electro)chemical reactions Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 5
Electrode slurry preparation Batch mixers High-speed dissolvers / dispersers Very versatile equipments Double wall tank for product cooling Basket mill for grinding High-shear planetary mixers Kneading of highly viscous slurries Slurries with higher solid content are achievable Slurry batch 1 20 L Slurry batch up to 60 L Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 6
Electrode slurry preparation Characterization Ink density Solid content Particle distribution / Agglomerates Grind gauge Particle size distribution Rheological properties Flow properties Surface energy Grind gauge Rheometer Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 7
Electrode coating Pre-pilot scale coating Comma-bar coating self-metered coating system One side coating Typical electrodes: L ~ 10 m Pilot-scale coating Slot-die coating pre-metered coating system 3m long dryer One side coated electrodes Typical electrodes: L ~ 100 m Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 8
Electrode coating Pre-industrial scale coating Slot-die coating Large area electrodes Double-side coated electrodes 6m long dryer Typical electrodes: L ~ 500 m Slurry feeding system Slot die Intermittent coating On-line monitoring (beta gauge, visio) Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 9 Electrode loading monitoring
Electrode processing Calendering: Decrease electrode porosity optimize electronic and ionic percolation, increase volumetric energy density Slitting: Electrode slitting with copper or aluminium foil Aspiration of small shavings Maximum width of electrode: 600 mm Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 10
Alpha = 228 Beta = 1 µm 2 1.8 1.6 1.4 1.73 µm 1.2 1 Electrode processing 198 µm 0.204 mm 0.8 0.6 0.4 0.2 0 Characterization Morphology / Structure: SEM, TEM Surface profilometry Residual moisture content Mechanical properties: peel strength test, flexibility test Electronic conductivity Electrochemical performances in coin cells Electrode surface profilometry 180 peel strength test Flexibility test Karl-Fischer titrator Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 11
Focus on water-based electrode manufacturing Reasons for a change: Environmental, health and costs concerns associated with the use of N-methyl pyrrolidone (NMP) NMP listed by ECHA as «Substance of Very High Concern» (SVHC) Restriction proposal 2013-2014: Public consultation Proposed solutions: Substitute NMP for a new solvent H 2 O is the best candidate to date Decrease or eliminate solvent content in the slurry Dry mix, extrusion Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 12
Focus on water-based electrode manufacturing Electrode manufacturing Materials selection, preparation and dosing Slurry preparation Electrode coating and drying Electrode calendering Electrode slitting Active material Conductor additives Polymer binders Solvent Collector foil Materials fractions Mixing equipment Mixing sequence Dispersion time Dispersion speed Mixing T C Coating speed Dryer T C Slurry mass flow Calendering T C Applied pressure Process parameters BET surface area (m²/g) D50 (µm) Dry content (%) Tap density (g/cm 3 ) Viscosity (Pa.s) Density (g/cm 3 ) «Macro» scale parameters Electrode loading (mg/cm²) Porosity (%) Peel strength force (N/m) Flexibility Residual H 2 O (ppm) End-user spec: Voltage, Energy density, Power Capability, Cycle life «Micro» scale properties Materials interactions, microstructures, (electro)chemical reactions Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 13
Issues associated with water-based cathodes + LTO Oxide active material instability in contact with water Surface hydroxides alkaline behaviour Li + /H + exchange Active material protection Slurry acidification M.A. Spreafico et al., PVDF Latex As a Binder for Positive Electrodes in Lithium- Ion Batteries, Industrial & Engineering Chemistry Research 53 (2014) 9094 9100 Mat4Bat project, Task 3.4 results: Electrode and aluminum surface micrographs NMC ink without ph regulation NMC ink with ph regulation Aluminum surface corrosion during coating / drying Slurry acidification Aluminum surface coating Corrosion inhibitors Thick electrode surface (wet thickness ~300µm) Scratched aluminum surface Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 14
Issues associated with water-based cathodes + LTO Issues regarding slurry wettability on aluminum Wettability improvement with surface pre-treatment (Corona ) Coating parameters adjustment ( coating window ) Poor electrochemical stability of polymer binders New polymer binders : PVdF latex, fluorine acrylic latex, polyvinyl acetate N. Yabuuchi et al., Electrochemical Properties of LiCoO2 Electrodes with Latex Binders on High-Voltage Exposure, Journal of the Electrochemical Society 162 (2015) A538 A544. Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 15
Results from Elibama FP7 project Objective: Coating of water-based LTO electrodes at pilot scale Manufacturing of 9 Ah NMC/LTO prismatic cells The ELIBAMA project is granted by the European Commission under the Nanosciences, nanotechnologies, materials & new production technologies (NMP) Theme of the 7th Framework Programme for Research and Technological Development. Slurry manufacturing process development in collaboration with Solvay Implementation of acidification step to avoid aluminum corrosion Water-based slurry parameters optimization to ensure good coating (solid content ) Low film formation temperature with Solef XPH-859 no need for thermal posttreatment Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 16
Results from Elibama FP7 project Pilot-scale coating of water-based LTO electrodes: Corona treatment as effective and «easy» method to degrease aluminum surface and improve surface wetting Improvement of wettability issues / No edge effect Improvement of coating process parameters to better coat LTO electrodes : slot die gap, dryer temperatures Homogeneous coating and electrode loading The ELIBAMA project is granted by the European Commission under the Nanosciences, nanotechnologies, materials & new production technologies (NMP) Theme of the 7th Framework Programme for Research and Technological Development. Great advantage of water-based process regarding electrode drying: Higher solid content / Lower furnace temperatures SIDE 1 Electrode characterization: Similar adhesion strength values Electrode flexibility OK for 10 Ah prototypes winding LTO (NMP, 2 sides) 1.3 mah/cm² LTO (H 2 O, 2 sides) 1.3 mah/cm² Pilot-scale coating 19.6 N/m 18.4 N/m 140 mm width Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 17
Results from Elibama FP7 project The ELIBAMA project is granted by the European Commission under the Nanosciences, nanotechnologies, materials & new production technologies (NMP) Theme of the 7th Framework Programme for Research and Technological Development. Cell manufacturing: Cell testing: H 2 O NMP @ RT LTO-NMP LTO electrode on the winding machine Winded cells with tabs NMP 140 mm 140 mm Cell with packaging (including extrapocket) H 2 O LTO-H 2 O Post-mortem analysis @ 55 C Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 18
Results from Mat4Bat WP4 Task 4.1 Electrode fabrication and cell assembly GEN1 electrode manufacturing of optimised formulations received from CIDETEC Slurry scale-up to 3kg (anode) and 6kg (cathode), coating and calendering Water-based formulation of Graphite anode materials from Imerys Water-based formulation of NMC 111 cathode material Mixing Coating Calendering Double-side coated electrode rolls manufactured for GEN1 cells Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 19
Results from Mat4Bat WP4 Task 4.1 Electrode fabrication and cell assembly GEN1 cell assembly: electrode cutting, electrode/separator lamination & stacking 54 stacks assembled: 50 cells to be sent for GEN1 electrolyte filling and formation by KIT Electrode die-cutting unit GEN1 cell: ~18Ah 17 anodes/16 cathodes VALIDATION : 4 cells filled with standard electrolyte under cycling tests at CIDETEC Cell stacking-winding unit Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 20
Conclusions & Perspectives Pilot lines in Europe are key facilities to help in electrode and cell technologies scaling-up Water-based electrode formulations: Great potential for European battery research and manufacturers: basic research, new materials, REACH regulation Scaling-up to ~ Ah cells level is now mandatory to address all issues Perspectives: Adapt today s process to up-coming new materials: high-voltage cathode, Sibased anodes, intercalation electrodes for Na-ion batteries Find new process evolutions to address next battery technologies: gelled electrolyte batteries, solid-state electrolyte batteries, metal-air batteries, etc. Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 21
MAT4BAT Advanced materials for batteries Summer School June 2-4 th 2015 «Electrode formulation and processing» Contact e-mail: dane.sotta@cea.fr Mat4Bat Summer School Dane Sotta (CEA) June 3 rd 2015 22