Project 1 - Simulating a BTMS

Lithium-ion batteries are widely used in electric vehicles (EVs) and hybrid electric vehicles (HEVs), in which proper measures have to be taken to ensure the batteries working with in a suitable temperature range. The air-cooling battery thermal management system (BTMS) is still a widely used solution for this purpose. Based on modeling and numerical simulation method, this paper aims to analyze and improve the cooling effect of the battery cells by optimizing the airflow configuration and layout employed in the U-type air-cooling BTMS. It is found that, for eighteen selected designs in the current study, the best cooling performance can be achieved when the number of both inlet and outlet manifolds is increased to be three. Further analysis is also carried out for the obtained optimum design to confirm its applicability in a wider range of total inlet airflow rates and temperatures.

Binder-free Co₃O₄ electrodes with hierarchical structures, nanoflowers and nanowire network, were directly grown on nickel foams with a facile hydrothermal strategy and subsequent annealing treatment. The architectures of the electrodes, flowers- or nanowires-dominated, can be selectively synthesized by simply controlling the reaction time of hydrothermal synthesis. It is clarified that the nanoflowers with mesoporous petals were constructed by the assembly of nanowires, resulting in the flowers-dominated Co₃O₄ electrode exhibiting enhanced electrochemical performance: including high specific capacitance (2.266 and 1.91 F cm⁻² at 1 and 10 mA cm⁻², respectively), remarkable rate capability and superior cycle stability. A cyclic voltammetry (CV) training technique was proposed to explore the full energy storage potential of Co₃O₄ electrode material for supercapacitors; after trained over 200 CV cycles at the scan rate of 5 mV s⁻¹, the specific capacitance of the flower-dominated electrode further enhanced from 2.266 to 4.472 F cm⁻² at current density of 1 mA cm⁻², coupled with excellent electrochemical performance: rate capability (80.3% capacity retention at 10 mA cm⁻²) and cycle stability (84.6% capacitive retention over 5000 GCD cycles). An asymmetric supercapacitor (ASC) was constructed by employing flower-dominated Co₃O₄ as positive electrode and activated carbon as negative electrode. The ASC device delivered a high energy density of 0.215 mWh cm⁻² at a power density of 1.49 mW cm⁻². This encouraging result reveals that the flower architecture is acceptable for electrode material and provides a highly efficient training process to significantly enhance the electrochemical performance for supercapacitors.