Wet and Dry Electrode Manufacturing and Thin-Film Technology

The performance of electrical energy storage devices is decisively influenced by the nature of the electrodes. According to the current state of the art, they are manufactured using a wet coating process. In this process, flowable masses consisting of active material, conductivity additives and the binder, dispersed in a solvent, are applied to electrically conductive carrier materials. The process chain – from the starting materials to the ready-to-use electrode – includes the process steps of mixing and dispersing, the wet application itself, the subsequent drying and, if necessary, calendering (densification). Each individual step must be adapted to the materials used and optimized with regard to the targets and requirements for the electrode. 

New materials and battery technologies often require the development of new manufacturing processes and techniques. To this end, we conduct research and development in the following areas: 

  • Mixing and coating technology, including scalability 
  • We offer recipe development and paste formulation for coating processes with doctor blade and slot die. The entire process can be carried out in both sheet-to-sheet and roll-to-roll processes under normal laboratory conditions (45% relative humidity) and under dry room conditions (relative humidity <2%). 
  • We produce electrodes for solid-state batteries with a sulfide-based electrolyte under an inert atmosphere
  • We also offer energy-efficient dry coating processes in a single-stage direct calendering process and a discontinuous hot pressing process
  • The Technical Center Vacuum Coating offers the possibility to carry out processes for thin-film batteries and corrosion protection layers.

Our R&D Services on the Topic »Wet and Dry Electrode Manufacturing and Thin-Film-Tehcnology« Include:

Wet Coating

Nassbeschichtung der Elektroden mit Rakel auf einem Filmziehgerät.
© Fraunhofer ISE
Wet coating of the electrodes with a doctor blade on a film casting machine.
Kalanderanlage des Fraunhofer ISE.
© Fraunhofer ISE
Calender system from the Fraunhofer Institute for Solar Energy Systems.
Vakuumtrocknungsofen mit programmierbarem Trocknungsrezept.
© Fraunhofer ISE
Vacuum drying oven with programmable drying recipe.

At Fraunhofer ISE, we are dedicated to the wet coating of cathode and anode materials, in particular for lithium-ion batteries. In addition to aqueous solvents, we also use N-methyl-2-pyrrolidone. The complete processing, from powder handling to calendered electrode, can be carried out under dry room conditions (<2% r.h.). We also process materials for sodium-ion batteries. 

 

Our R&D Services in the Area of “Wet Coating” Include:  

  • Binder premix production, solubility determination  
  • Paste formulations (active material, binder, conductive additive, solvent) up to 5 liters
  • Electrode production in a sheet-to-sheet process on a film drawing device with a doctor blade 
  • Electrode drying (electrode sheet & coils up to Ø300mm) 
    • ATEX temperature cabinets up to 150°C 
    • Vacuum drying  
      • Fine vacuum up to 10-3mbar
      • Jacket heating up to 150°C 
  • Electrode production in roll-to-roll process with doctor blade or slot die
  • Substrate width (roll material): max. 300mm, 3“ or 6” core
  • Maximum coating width: 280 mm
  • Inline grammage measurement with X-ray
  • Layer thickness measurement
  • Heavy-edge detection 
  • Inline convection drying (optional: (near-) infrared, laser, induction) 
  • Calendering of the electrodes either in sheet-to-sheet or roll-to-roll processes 
  • Substrate width (roll material): max. 300mm, 3“ or 6” core 
  • Coating width: 100mm – 295 mm 
  • Heatable calender rollers up to 150°C 
  • Line load up to 1.5 kN/mm  

Dry Coating

Kalanderaufbau zur Versuchsdurchführung von Direktkalandrierungen.
© Matthews International GmbH
Calender structure for conducting direct calendering trials.

In the field of dry electrode production, we are dedicated to the direct pressing of pre-prepared dry masses in a calender gap and to the hot-press process. We offer process development from (multi-stage) dry mixing or granulation to electrode production for lithium and sodium ion materials. Furthermore, we offer the option of dry electrode production in our drying room (<1 r.h., dew point down to -55°C). For zinc-ion technology, we also offer the development of thick-film electrodes. 

 

Our R&D Services in the Area of “Dry Coating” Include: 

  • Preliminary tests in the area of
  • Dry mixing
  • Post-structuring/grinding
  • Testing of premixes for direct pressing in the calender nip
  • Electrode widths between 100 and 200 mm 
  • Development of suitable feeding systems
  • Granulate development for use in the hot-press process 
  • Electrode production in the hot-press process up to 200 x 200 mm²

More Information on this Research Topic

 

Research Topic

Technology Evaluation for Batteries

 

Reserach Topic

Production Technology for Batteries

 

Research Topic

Battery Materials and Cells

 

Business Area

Electrical Energy Storage

 

R&D Infrastructure

Center for Electrical Energy Storage