Single cell temperature difference of lithium-ion battery(LIB) module will significantly affect the safety and cycle life of the battery. The reciprocating air-flow module created by a periodic reversal of the air flow was investigated in an effort to mitigate the inherent temperature gradient problem of the conventional battery system with a unidirectional coolant flow with computational fluid dynamics(CFD). Orthogonal experiment and optimization design method based on computational fluid dynamics virtual experiments were developed. A set of optimized design factors for the cooling of reciprocating air flow of LIB thermal management was determined. The simulation experiments show that the reciprocating flow can achieve good heat dissipation, reduce the temperature difference, improve the temperature homogeneity and effectively lower the maximal temperature of the modular battery. The reciprocating flow improves the safety, long-term performance and life span of LIB.
A new functionalized heteroleptic iridium complex coordinated with 1-phenylisoquinoline(1-piq) and a functionalized β-diketone(G1),Ir(1-piq)2G1,was synthesized and characterized by 1H-NMR,mass spectrometry and elemental analysis.The larger conjugation of the replacement of acetylacetone(acac) by a functionalized β-diketonate ligand led to a significant decrease in the HOMO level toward vacuum level,while Ir(1-piq)2G1 and Ir(1-piq)2(acac) showed red phosphorescent emissions of about 620 nm in dichloromethane solution.The phosphorescent polymer light-emitting devices were achieved,with the complexes incorporated with polyfluorene(PFO) as a host polymer doped with 30% of 5-(4-biphenylyl)-2-(4-tert-butylphenyl)-1,3,4-oxadiazole(PBD) as electron transport material.The energy transfer mechanism of the devices was also discussed.The lower EL performance of Ir(1-piq)2G1 is ascribed to the inter-ligand energy transfer,indicating that it is important to control the energy level of the cyclometalated and ancillary ligands.
