In the project, safety-critical conditions for lithium-ion batteries are to be investigated. The investigations start from specially manufactured cells with deviating production parameters, such as incomplete electrolyte wetting or incorrect electrode positioning, in order to simulate aging-related effects in the cell that result in safety-relevant effects, such as lithium plating. In addition to the cells manufactured in-house commercially available cells that serve as a reference will also be investigated. The main component is the quantification of metallic lithium deposited on anode surfaces by gas chromatography. The aim is to establish a possible connection between production defects and lithium plating. Here, the analysis is performed on post-cycling cells that are opened in the glovebox under an argon atmosphere. For quantification, the stoichiometric reaction of metallic lithium with water is utilized, whereby lithium plating can be quantified via the hydrogen content. By cutting the anodes into smaller segments, a coarse spatial resolution of the gas chromatographic investigations can be achieved. For a more precise spatial resolution and to investigate the homogeneity and reversibility of the deposited lithium, the analysis of selected cells is performed by laser ablation ICP-MS (LA-ICP-MS). In addition, LA-ICP-MS studies provide information on the migration of transition metals from the cathode to the anode. Furthermore, anodes of the in situ cells are investigated by means of LA-ICP-MS to find out if reversible lithium plating can be detected after its reversible lithium plating can be detected qualitatively or even quantitatively.