Since the market launch of lithium-ion cells for electric cars, electric bikes and energy storage systems, the detailed analysis of aged or defective batteries is increasingly gaining in importance. In the case of damage assessment, it is often a question of whether incorrect use, production errors or weakness in the construction caused the adverse effect.
Our core areas of expertise include cell opening and post-mortem analyses as well as non-destructive X-ray computed tomographic tests on batteries and cells. Our facilities comprise a very good infrastructure with professional work stations for cell opening and a X-ray computed tomograph.
We are specialised in cell opening and post-mortem analyses for analysing damage and assessing new or aged cells. The analytical results are essential for understanding ageing processes, potential safety risks and for optimising cell design.
All types of batteries are tested: from conventional lead-acid batteries and lithium-ion batteries to the new supercaps. All sizes can be professionally tested up to a capacity of 400 ampere hours, be they cylindrical cells, pouch cells or prismatic cell designs. For this purpose, our facilities include professional work stations for opening cells.
Damage mechanisms can be established from the result of the post-mortem analysis. For example, in a study with commercial 18650 lithium batteries we found that the ageing mechanism changes with the ambient temperature. The decomposition of the conducting salt on the surface of the anode occurs at higher temperatures, whereas at lower temperatures metallic lithium settles on the anode (see Figure).
Once the cells are opened, ZSW has a large range of physical-chemical analysis methods for investigating the damage mechanisms: using SEM, EDX, ICP-OES, XRD and GC-MS, we can comprehensively investigate all the cell components (anodes, cathodes, separators and electrolytes) at our facilities.