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The mechanical properties of aged and fresh lithium ion cell components are evaluated in this paper. Cells components were obtained from destructive physical analysis of 40Ah NMC/Graphite-based pouch cells before and after cycling and were subjected to mechanical testing. The aging tests comprised of cycling the cell across a voltage window of 4.1V to 3.0V at room temperature (25℃). Using a 2C charging rate and 1C discharging rate, the cells were subjected to over 5600 cycles before a 80% drop in the name-plate capacity was observed. Mechanical tests, including compression test, tensile test and indentation test, were conducted on the cell components to investigate differences in the mechanical performance. Comparison of the fresh and aged cells components shows that cycling the cells has different degrees of impact on the different cell components. Anodes suffered the most serious deterioration in mechanical properties while separators remained intact under the test condition investigated.

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An effective cooling mechanism is the backbone of a good automotive battery thermal management system (BTMS). In addition to prevention of extreme events such as thermal runaway, an automotive BTMS must be able to efficiently tackle aggressive environmental temperatures, and/or discharge and charge conditions during electric vehicle operation. Moreover, electrical performance and cycle life of the battery modules and packs are closely tied to the battery temperatures and thermal gradients, which increase with increase in C-Rates. In order to keep the battery temperatures to be under the operational temperature limit, it is crucial that the selected cooling mechanism provides efficient transport of the heat generated by the battery modules and packs to the cooling media under all discharge and charge conditions. Owing to its efficient thermal performance, liquid cooling is preferred by most electric vehicle manufacturers for battery thermal management. This usually incorporates battery modules exchanging heat with a flowing coolant via cold plate or cooling channels during operation. The current work aims to investigate different liquid cooling configurations and compare their relative thermal performance during operation of a high energy density Pouch Cell. The four configurations selected for this comparison are (1) Face cooling, (2) Single-Sided cooling, (3) Double-Sided cooling, and (4) a Hybrid cooling configuration. Test setups comprising of a commercially available 9 A-h NMC Pouch cell, cold plates, pump, heat exchanger, refrigeration cooling unit, and thermal sensors are built for the above four cooling configurations. During the tests, the selected cell is discharged at different discharge rates (C-Rates), i.e., 3C, 4C, and 5C. The overall cell temperatures and thermal gradient across the cell are measured using T-type thermocouples for the four cooling configurations. In order to capture the thermal gradient across the Pouch cell accurately, several thermocouples on the face of the cell are installed using a thermal interface material. Results show the superiority of Face cooling configuration in terms of overall thermal performance under all considered test conditions. Lowest cell temperatures and thermal gradients across the cell are observed for the Face cooling configuration, while highest temperatures and thermal gradients are observed for the Single-Sided cooling configuration. Much improved thermal performance is also observed in the case of the Hybrid cooling configuration as compared to the Single and Double-Sided cooling configurations. As implementation of the Face cooling configuration at the battery pack level may result in higher weight and cost of the battery pack, owing to its good thermal performance and straightforward scaling to battery pack level, the proposed hybrid liquid cooling mechanism provides a viable alternative to Face cooling for battery thermal management.

Objective. The prefrontal-limbic system is closely associated with emotion processing in both unipolar depression (UD) and bipolar depression (BD). Evidence for this link is derived mostly from task-fMRI studies, with limited support from structural findings. Therefore, this study explores the differences in the emotional circuit in these two disorders on a structural, large-scale network basis, coupled with the highly noted inflammatory and growth factors. Methods. In this study, 31 BD patients, 37 UD patients, and 61 age-, sex-, and education-matched healthy controls (HCs) underwent diffusion-weighted imaging (DWI) scanning and serum cytokine sampling. The study compared cytokine levels and prefrontal-limbic network alterations among the three groups and explored potential biological and neurobiological markers to distinguish the two disorders using graph theory, network-based statistics (NBS), and logistic regression. Results. Compared to BD patients, UD patients showed greater s-100β protein levels, higher efficiency of the right amygdala, and significantly elevated prefrontal-cingulate-amygdala subnetwork intensity. Importantly, the altered prefrontal-cingulate-amygdala subnetwork, nodal efficiency of the right amygdala, IL-8, IL-17, and s-100β levels were risk factors for the diagnosis of UD, whereas anxiety symptoms tended to closely correlate with BD. Moreover, binary logistic regression manifested these factors achieved an area under the curve (AUC) of the receiver operating characteristics (ROC) of 0.949, with 0.875 sensitivity and 0.938 specificity in UD vs. BD classification. Conclusions. These findings narrow the gap in the structural network of emotional circuits in bipolar and unipolar depression, pointing to distinct emotion-processing mechanisms in both disorders.