“In God We Trust:” The U.S. National Motto and the Contested Concept of Civil Religion

In this essay, “In God We Trust”, the official motto of the United States, is discussed as an illustration of the contested character of American civil religion. Applying and evaluating assumptions from Robert N. Bellah and his critics, a conceptual history of the motto is presented, showing how from its first appearance to today it has inspired debates about the place of civil religion in American culture, law, and politics. Examining these debates, the changing character of the motto is explored: its creation as a religious response to the Civil War; its secularization as a symbol on the nation’s currency at the turn of the twentieth century; its state-sponsored institutionalization during the Cold War; its part in the litigation that challenged the constitutionality of civil religious symbolism in the era of the culture wars; and its continuing role in the increasingly partisan political battles of our own time. In this essay, I make the case that, while seemingly timeless, the meaning of the motto has been repeatedly reinterpreted, with culture, law, and politics interacting in sometimes surprising ways to form one of the nation’s most commonly accepted and frequently challenged symbols. In concluding, I speculate on the future of the motto, as well as on the changing place of civil religion in a nation that is increasingly pluralistic in its religion and polarized in its politics

Durable Fast Charging of Lithium-Ion Batteries Based on Simulations with an Electrode Equivalent Circuit Model

Fast charging of lithium-ion batteries is often related to accelerated cell degradation due to lithium-plating on the negative electrode. In this contribution, an advanced electrode equivalent circuit model is used in order to simulate fast-charging strategies without lithium-plating. A novel parameterization approach based on 3-electrode cell measurements is developed, which enables precise simulation fidelity. An optimized fast-charging strategy without evoking lithium-plating was simulated that lasted about 29 min for a 0–80% state of charge. This variable current strategy was compared in experiments to a conventional constant-current–constant-voltage fast-charging strategy that lasted 20 min. The experiments showed that the optimized strategy prevented lithium-plating and led to a 2% capacity fade every 100 fast-charging cycles. In contrast, the conventional strategy led to lithium-plating, about 20% capacity fade after 100 fast-charging cycles and the fast-charging duration extended from 20 min to over 30 min due to increased cell resistances. The duration of the optimized fast charging was constant at 29 min, even after 300 cycles. The developed methods are suitable to be applied for any given lithium-ion battery configuration in order to determine the maximum fast-charging capability while ensuring safe and durable cycling conditions

Electrical Characterization of Li-Ion Battery Modules for Second-Life Applications

The reuse and repurposing of lithium-ion batteries for transportation in stationary energy systems improve the economic value of batteries. A precise suitability test at the beginning of the second life is therefore necessary. Common methods such as electrochemical impedance spectroscopy (EIS) and current interrupt (CI) analysis, as well as capacity analysis, can be used for testing. In this paper, these methods are studied from the aspects of test duration, sensitivity and acquisition costs of the measuring instruments. For this purpose, tests are carried out on battery modules, which were used for transportation. It is shown that subtle differences are better detected with EIS and less accurately with the CI method. The test duration is fastest with the CI method, followed by EIS and the capacity test. Strongly aged modules are reliably detected with all methods

Key Figure Based Incoming Inspection of Lithium-Ion Battery Cells

The cell characterization in the incoming inspection is an important but time and cost intensive process step. In order to obtain reliable parameters to evaluate and classify the cells, it is essential to design the test procedures in such a way that the parameters derived from the data allow the required statements about the cells. Before the focus is placed on the evaluation of cell properties, it is therefore necessary to design the test procedures appropriately. In the scope of the investigations two differently designed incoming inspection routines were carried out on 230 commercial lithium-ion battery cells (LIBs) with the aim of deriving recommendations for optimal test procedures. The derived parameters of the test strategies were compared and statistically evaluated. Subsequently, key figures for the classification were identified. As a conclusion, the capacity was confirmed as an already known important parameter and the average cell voltage was identified as a possibility to replace the usually used internal resistance. With regard to capacity, the integration of CV steps in the discharging processes enables the determination independently from the C-rate. For the average voltage cycles with high C-rates are particularly meaningful because of the significant higher scattering due to the overvoltage parts