262 research outputs found
Cerberus: A Deep Learning Hybrid Model for Lithium-Ion Battery Aging Estimation and Prediction Based on Relaxation Voltage Curves
The degradation process of lithium-ion batteries is intricately linked to
their entire lifecycle as power sources and energy storage devices,
encompassing aspects such as performance delivery and cycling utilization.
Consequently, the accurate and expedient estimation or prediction of the aging
state of lithium-ion batteries has garnered extensive attention. Nonetheless,
prevailing research predominantly concentrates on either aging estimation or
prediction, neglecting the dynamic fusion of both facets. This paper proposes a
hybrid model for capacity aging estimation and prediction based on deep
learning, wherein salient features highly pertinent to aging are extracted from
charge and discharge relaxation processes. By amalgamating historical capacity
decay data, the model dynamically furnishes estimations of the present capacity
and forecasts of future capacity for lithium-ion batteries. Our approach is
validated against a novel dataset involving charge and discharge cycles at
varying rates. Specifically, under a charging condition of 0.25C, a mean
absolute percentage error (MAPE) of 0.29% is achieved. This outcome underscores
the model's adeptness in harnessing relaxation processes commonly encountered
in the real world and synergizing with historical capacity records within
battery management systems (BMS), thereby affording estimations and
prognostications of capacity decline with heightened precision.Comment: 3 figures, 1 table, 9 page
Investigating the critical characteristics of thermal runaway process for LiFePO4/graphite batteries by a ceased segmented method
Lithium-ion batteries (LIBs) are widely used as the energy carrier in our daily life. However, the higher energy density of LIBs results in poor safety performance. Thermal runaway (TR) is the critical problem which hinders the further application of LIBs. Clarifying the mechanism of TR evolution is beneficial to safer cell design and safety management. In this paper, liquid nitrogen spray is proved to be an effective way to stop the violent reaction of LIBs during the TR process. Based on extended-volume accelerating rate calorimetry, the liquid nitrogen ceasing combined with non-atmospheric exposure analysis is used to investigate the TR evolution about LiFePO4/graphite batteries at critical temperature. Specifically, the geometrical shape, voltage, and impedance change are monitored during the TR process on the cell level. The morphologies/constitution of electrodes and separators are presented on the component level. Utilizing the gas analysis, the failure mechanism of the prismatic LiFePO4/graphite battery is studied comprehensively
In-Plane Anisotropies of Polarized Raman Response and Electrical Conductivity in Layered Tin Selenide
The group IV-VI compound SnSe, with an orthorhombic lattice structure, has
recently attracted particular interest due to its unexpectedly low thermal
conductivity and high power factor, showing great promise for thermoelectric
applications. SnSe displays intriguing anisotropic properties due to the
puckered low-symmetry in-plane lattice structure. Low-dimensional materials
have potential advantages in improving the efficiency of thermoelectric
conversion, due to the increased power factor and decreased thermal
conductivity. A complete study of the optical and electrical anisotropies of
SnSe nanostructures is a necessary prerequisite in taking advantage of the
material properties for high performance devices. Here, we synthesize the
single crystal SnSe nanoplates (NPs) by chemical vapor deposition. The angular
dependence of the polarized Raman spectra of SnSe NPs shows anomalous
anisotropic light-mater interaction. The angle-resolved charge transport of the
SnSe NPs expresses a strong anisotropic conductivity behavior. These studies
elucidate the anisotropic interactions which will be of use for future
ultrathin SnSe in electronic, thermoelectric and optoelectronic devices.Comment: 25 pages, 9 figures, 3 table
A method to prolong lithium-ion battery life during the full life cycle
Extended lifetime of lithium-ion batteries decreases economic costs and environmental burdens in achieving sustainable development. Cycle life tests are conducted on 18650-type commercial batteries, exhibiting nonlinear and inconsistent degradation. The accelerated fade dispersion is proposed to be triggered by the evolution of an additional potential of the anode during cycling as measured vs. Li/Li. A method to prolong the battery cycle lifetime is proposed, in which the lower cutoff voltage is raised to 3 V when the battery reaches a capacity degradation threshold. The results demonstrate a 38.1% increase in throughput at 70% of their beginning of life (BoL) capacity. The method is applied to two other types of lithium-ion batteries. A cycle lifetime extension of 16.7% and 33.7% is achieved at 70% of their BoL capacity, respectively. The proposed method enables lithium-ion batteries to provide long service time, cost savings, and environmental relief while facilitating suitable second-use applications
Optical investigation of the charge-density-wave phase transitions in
We have measured the optical reflectivity of the quasi
one-dimensional conductor from the far infrared up to the
ultraviolet between 10 and 300 using light polarized along and normal to
the chain axis. We find a depletion of the optical conductivity with decreasing
temperature for both polarizations in the mid to far-infrared region. This
leads to a redistribution of spectral weight from low to high energies due to
partial gapping of the Fermi surface below the charge-density-wave transitions
at 145 K and 59 K. We deduce the bulk magnitudes of the CDW gaps and discuss
the scattering of ungapped free charge carriers and the role of fluctuations
effects
Early patterning of cloned mouse embryos contributes to post-implantation development
AbstractSeveral research groups have suggested that the embryonic–abembryonic (Em–Ab) axis in the mouse can be predicted by the first cleavage plane of the early embryo. Currently, it is not known whether this early patterning occurs in cloned embryos produced by nuclear transfer and whether it affects development to term. In this work, the relationship between the first cleavage plane and the Em–Ab axis was determined by the labeling of one blastomere in cloned mouse embryos at the 2-cell stage, followed by ex-vivo tracking until the blastocyst stage. The results demonstrate that approximately half of the cloned blastocysts had an Em–Ab axis perpendicular to the initial cleavage plane of the 2-cell stage. These embryos were classified as “orthogonal” and the remainder as “deviant”. Additionally, we report here that cloned embryos were significantly more often orthogonal than their naturally fertilized counterparts and overexpressed Sox2. Orthogonal cloned embryos demonstrated a higher rate of post-implantation embryonic development than deviant embryos, but cloned pups did not all survive. These results reveal that the angular relationship between the Em–Ab axis and the first cleavage plane can influence later development and they support the hypothesis that proper early patterning of mammalian embryos is required after nuclear transfer
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