Battery Cell Development

Prototype Cell Assembly

Fraunhofer IWS aims to transfer new Material Developments and innovative cell systems into multilayer pouch cells and to investigate them under application-oriented conditions. This is based on a flexible manufacturing chain and many years of experience in the assembly of prototype battery cells. Electrodes can be produced using conventional slot-die coating technology as well as the Fraunhofer IWS DRYtraec® process. In this way, we offer customer-specific solutions for the production of small series or experimental batches within the framework of pouch cell campaigns for the following cell chemistry systems:

• Lithium-sulfur
• Solid-state batteries (sulfide-based)
• Sodium-ion
• Lithium-ion

Electrode Manufacturing

To evaluate new materials in application-oriented pouch cells, electrode production is essential. At Fraunhofer IWS, various processes and equipment are available to produce double-sided coated electrodes from powdered starting materials. Processing can be done using liquid solvents or dry (DRYtraec®). In addition to producing electrodes from very small quantities into electrode sheets, it is also possible to manufacture electrode coils. Fraunhofer IWS equipment enables the handling of moisture-sensitive materials (e.g., high-nickel NCM, sulfide-based solid electrolytes) as well as special conductive additives such as carbon nanotubes. Furthermore, methods exist to produce next-generation anodes, such as thin lithium and columnar silicon thin films, via physical deposition.

Process Development for the Assembly of Lithium-metal Pouch Cells

A laser cutting system enables fully automated lithium anode slitting from the roll. The system is part of a complex for the automated production of multilayer pouch cells. A process innovation also allows burr-free cutting of lithium anodes – a challenge in lithium-metal battery manufacturing until now. In addition, an innovative method has been developed for laser welding lithium tabs to the current collector tab.

Process Development for the Assembly of Sulfide-based Solid-state Battery Pouch Cells

For the assembly of SSB pouch cells with sulfide-based electrolytes, various processes are applied and studied. In addition to the dry production of electrodes and separators using moisture-sensitive sulfide solid electrolytes, their processing via laser cutting, as well as uniaxial and isostatic pressing, are subjects of ongoing research and development. The evaluation of individual manufacturing steps can be carried out process-specifically or holistically within complete SSB pouch cells.

Cell Testing

The evaluation of battery cells is carried out according to application-specific test protocols and under defined external conditions. Temperature and cell pressure can be precisely controlled. A special experimental setup allows thickness monitoring during cell operation. More than 300 channels are available for testing.