The deposition of metallic lithium, so called lithium plating, is a critical aging mechanism in lithium ion cells. Lithium plating occurs mainly at low temperatures or due to high charging currents and leads to a rapid decrease in cell capacity and power. Moreover, lithium plating can negatively affect the safety of a lithium ion cell. Thus, operating conditions under which lithium plating can occur should be determined carefully and avoided during normal operation. Furthermore, lithium plating presents a major challenge for aging modeling and simulation of lithium ion cells. Common empirical aging models are based on accelerated cell tests. If these tests are accelerated by increasing the charging currents above the limits for normal operation, lithium plating can occur which makes it challenging to draw conclusions from these tests for cases where lithium plating is actively avoided. In this thesis aging tests have been performed on automotive lithium ion cells to investigate the transferability of accelerated cycle tests to scenarios where regular longer rest periods are expected. It was observed that the cell capacity can increase significantly during rest periods. This behavior has been linked to the occurrence of lithium plating in the preceding cycles. In addition to this short term behavior cells which had regular rest periods during cycling showed overall longer life times compared to cells which were cycled without rest periods. Thus, a microscopic model is postulated to explain this effect. It is assumed that repeatedly occurring lithium plating can be encapsulated by an electronically insulating layer but still remains in mechanical contact to the anode particles. During rest periods some electrons cross the insulating layer which reactivates the encapsulated lithium ions. This mechanism should be kept in mind when developing and parameterizing aging models. In order to further investigate the influence of lithium plating on the aging behavior respectively the influence of other aging mechanisms on the lithium plating behavior, a novel 3-electrode cell design has been developed in this work. Thus, an aluminum mesh coated with lithium titanate (LTO) is inserted in between the anode and the cathode of lab sized lithium ion cells. The LTO acts as a reference electrode which allows the detection of the anode and cathode potentials independently during cell operation. The observation of the anode potential during charging gives insight into the lithium plating behavior since the anode potential has to fall below 0V vs. Li/Li+ before it can occur. Thus, the maximum charging current can be measured with respect to cell temperature and state of charge which just avoids lithium plating. Therefore, 3-electrode measurements allow the determination of an optimized charging current profile. Since LTO is chemically inert inside the cell, these 3-electrode cells can undergo aging tests like regular cells and allow insight into the lithium plating behavior even after aging. Using this, it was found that aging under demanding conditions can lead to increased susceptibility to lithium plating. In contrast to this, aging under less challenging conditions appears to reduce the susceptibility for lithium plating at first.weiterlesen