Papers by Keyword: Lithium-Ion

Abstract: The battery remains the primary choice of energy and power storage in electric vehicles. To optimize battery performance, manufacturers have developed various technologies, including the battery thermal management system (BTMS). In this study, an experimental investigation was conducted to determine the cooling performance and characteristics of a liquid cold plate cooling system for 18650 lithium-ion battery. The testing involved an 18650 SONY 2100 mAh lithium-ion battery and a 400 W DC Load Tester. Testing was carried out by discharging the battery module and taking data on battery temperature and working fluid temperature to get the heat transfer coefficient. The discharge current varied at 1.25 C, 1.5 C, 1.75 C, and 2 C, while the flow rate was set at 0.2 LPM, 0.5 LPM, and 0.8 LPM. The results indicate that the cooling rate increases as the flow rate rises. The battery temperature rises quicker near the negative pole than at the further location. Furthermore, the pressure drop on the liquid cold plate increases as the flow rate rises, while the highest heat transfer coefficient to pressure drop ratio is observed at 0.2 LPM.

Abstract: Lithium iron phospate-carbon composite (LiFePO₄/C) was successfully synthesized with various sintering temperature in order to find best synthesis condition resulting high quality of LiFePO₄/C that can be applied for environmentally friendly of cathode in lithium ion battery. It is found that the specific capacity and the stability capacity of LiFePO₄/C were improved to 17.6 mAh and 40.3% of capacity loss, respectively.

Abstract: Most African remote telecoms base stations are powered from diesel generators, however, these generators are losing attractiveness due to their less reliability in addition to high operational and maintenance costs. Over 65% of the loss of telecom services observed in remote areas are caused by outages resulting from diverse types of failures that these generators can suffer, on top of their impacts on the environment. As alternative, off-grid renewable energy systems are often employed in place of diesel generators due to their capability to provide reliable electricity at an acceptable cost. This study proposes an off-grid system based on PV generators and backup energy storage consisting of lithium-ion batteries as an extended solution for powering remote telecom base stations in Africa. Modelling and simulation is performed using Matlab/Simulink environment. The findings showed better characteristics of lithium-ion battery bank as compared to lead-acid unit; lithium-ion battery bank displayed higher initial current and voltage over lead-acid battery bank. Moreover, when, both battery banks reached 50 % of their state of charge, lithium-ion bank current was still higher than that of lead-acid bank. In the same vein, lithium-ion battery bank presented a slower discharge time than lead-acid battery bank on top higher values at 50 % and 70% state of charges. Lastly, the state of charge of the lead-acid battery at the end of the simulation was 50 %, while that of the lithium-ion battery bank was around 60 %.

Abstract: In this work, we prepared the sandwich-like carbon@SnO₂@carbon hollow spheres by templating against polystyrene spheres. The hollow spheres are characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD). The electrochemical performance as the anodes of lithium-ions batteries are studied by the cyclic voltammogram (CV) and galvanostatic discharge-charge voltage tests. Because of the interesting structure, the as prepared carbon@SnO₂@carbon hollow spheres deliver a reversible capacity of 492 mA h g^-1 after 50 cycles at a high current density of 400 mA g^-1.

Abstract: Both the performance and lifetime of battery pack are substantially reduced in the cold temperatures, and it influences the performance and cost of electric vehicle strongly. Reasonable and effective heating system becomes very critical for solving the problem. This paper introduces the research development of heating system in the world, including the primary cause of the poor performance of battery pack at cold temperatures and heating of batteries, analyses the methods of heating that have been used or are researching. The limitation of current heating systems is pointed out for the future research.

Abstract: The first-principle calculation method with plane-wave basis and pseudo-potentials was employed to investigate the intercalation/extraction mechanism of lithium in NiSn₃Sb₄. The insertion/substitution formation energies and the electronic structures of NiSn₃Sb₄ as well as its lithiated products were studied in order to research the migration path of lithium intercalation. The results show that lithium would firstly occupy interstitial sites, then Ni and Sn atoms are replaced gradually by additional lithium. The dissociated Ni atom can relieve the volume expansion and improve the recycling performance of the crystal. It can be also found that as lithium atoms insert into host material, intense electron transport from Li2s to Sn5p and Sb5p occurs at the Fermi level.

Abstract: The compositions La0.56Li0.33TiO2.95F0.05•xLiF (x=0-025) were prepared by addition of LiF to the disordered form of the well-known Li ion conductor La0.56Li0.33TiO3. Although the total conductivities improved, there was no change in the bulk conductivity with LiF addition. No reflections due to LiF were observed in their XRD patterns, and the profiles and the chemical shifts of their 19F MAS-NMR resonances were almost the same as those of LiF. The results indicate that no substitution of F takes place, and that the added LiF acts simply as a sintering assistant agent.

Abstract: In order to reproduce the observed ionic conductivities and activation energies computationally, the potential parameters (PMs) were optimized for classical molecular dynamic simulations on Li ion conduction in the A-site deficient perovskite solid solution La056Li0.33TiO3 with disordered A-site ion arrangement. By the use of the optimized PMs, the conductivities and the activation energies were improved considerably from 4.1×10-3 Scm-1 to 4.4×10-2 Scm-1 at 800 K and 0.02 eV to 0.2 eV, respectively. The pair correlation functions calculated with the optimized PMs reveal that the Li-ions are located somewhat broadly mainly in the vicinity of the midpoint between the center of the A-site and the center of the bottleneck formed by four O2-, and that the simulated Li location is significantly related to the conductivity.

Abstract: Phase studies and ac-conductivity measurements were carried out in the compositions M0.8In0.2Li0.2P2O7 [MILP] (M=Sn, Zr, Ti). The bulk conductivities were of the order of ~10-5 Scm-1 at 623 K and higher in the order of TiILP≥ZrILP>SnILP. The activation energies, as expected, became lower in the order of ZrILPSnILP in bulk conductivities were not correlated with that of the activation energies probably because of the impureness of the ZrILP sample.

Abstract: The locations and local environments of the Li ions in La0.56Li0.33TiO3 have been investigated by classical molecular dynamics (MD) simulations and first-principles (FP) calculations. The pair correlation functions of Li-O and Li-Ti indicate that the Li ions are located somewhat broadly mainly in the vicinity of the midpoint between the center of the A-site and the center of the bottleneck formed by four O2-. This is consistent well with that suggested from previous neutron diffraction and 6Li-NMR studies. The FP calculations suggest a different location of the Li ion in the vicinity of the midpoint between the centers of two adjcent bottlenecks; however it coincides with one of the locations shown by the trajectories simulated with the MD calculations.