Cell Concepts

Group

Components and characterization of ceramic solid-state batteries.
Bipolar cell concept for Li-ion batteries.
Battery test stand for the characterization of IKTS lab cells.

The Cell Concepts working group actively develops, builds and characterizes test and demonstrator cells for novel battery concepts. The group focuses on all-solid-state technologies, where the electrolyte is replaced by other materials, from polymers to fully inorganic concepts. An integrated system consisting of several gloveboxes is available for the production of the cells for solid-state batteries. It allows to cover all processes, starting with the manufacture of the individual cell components and including contacting (lithium, metals, etc.), through to cell assembly in an argon protective atmosphere.

For use in solid-state batteries, Fraunhofer IKTS develops and synthesizes active materials with optimized electrochemical properties and adapted particle morphology as well as inorganic electrolytes based on ion-conducting glasses and ceramic materials, but also specially structured and built composites from active materials, a conductivity additive and a solid electrolyte. Furthermore several cooperation initiatives exist with various partners, for instance for the development and synthesis of polymeric electrolyte materials. Based on these innovative materials, the Cell Concepts working group develops novel cell structures with monopolar or bipolar design.

Another point of activity is the characterization of commercial Li-ion batteries and cells, as well as their post-mortem analysis. The group benefits from its vast experience in the cell types it has analyzed and assessed (coin, pouch, bipolar and commercial cells). In terms of experimental tools, the institute’s analytical equipment is complemented by special gloveboxes in addition to the battery test stands, and by transfer devices. The focus is on the analysis of defects in the cell structure as well as signs of degradation due to material and process reasons. The extensive analytical capabilities of IKTS are available for this purpose.

In addition to the development of new cell concepts for the next generation of batteries, recycling strategies are also playing an increasingly important role. The working group is working on concepts for safe and fast deep discharge as well as the resynthesis of battery materials from recovered raw materials. The focus is always on the adaptation or even new development of recycling processes as well as their economic and ecological evaluation. Another focus is on cell optimization in terms of design and materials technology with a view to the recycling process, i.e., the recycling-friendly design of battery cells.

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Services offered#

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  • Electrical, electrochemical and material-analytical characterization of materials and components for solid-state batteries and Li-ion batteries
  • Material and technology characterization based on test and demonstrator cells (coin, pouch and bipolar cells)
  • Technology assessment of solid-state batteries and consulting on cell concepts
  • Characterization of performance and aging properties of solid-state batteries under defined conditions (-20 to 120 °C)
  • Investigations with impedance spectroscopy and cycle tests up to 400 A
  • Post-mortem analyses of conventional cells to identify root causes for cell failure and aging mechanisms
  • Definition of simulation parameters based on post-mortem analyses of battery cells (e. g. lithium-ion batteries)
  • Modeling of deep discharge processes
  • Characterization of (resynthesized) active materials
  • Economic and ecological evaluation of recycling processes
  • Design of battery cells suitable for recycling

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Technical equipment#

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  • Integrated glovebox system under argon atmosphere with powder preparation technology, furnace technology (up to 1200 °C) and hot press as well as a vapor deposition chamber for lithium and other metals in a vacuum
  • Glovebox system for handling sulfidic solid electrolytes (thiophosphates), for component and cell production
  • Two gloveboxes for the manufacture of coin, pouch and bipolar cells
  • Dedicated glovebox for post-mortem analysis
  • Various potentiostats for electrochemical characterization (approx. 120 channels)
  • Measuring station with Faraday cage (e.g. for Hebb-Wagner polarization measurements or high-impedance testing)
  • Measuring station for electrical conductivity
  • Equipment for the manufacture of electrodes at laboratory scale (material tests), mixing technology, film applicator
  • Equipment for coin and pouch cell production
  • Equipment for sampling and transport in protective atmosphere for subsequent material analytics

Current research

Development of processes for sulfide electrolyte-based solid-state batteries

Current research

EMBATT – bipolar lithium-ion battery for safe driving with great range

Topic

Battery recycling

Topic

Cell benchmarking and post-mortem analysis of commercial lithium batteries

Topic

Cell design and validation in test cells

Topic

Material development and assessment

Topic

Solid-state battery