A New Concept of Air Cooling and Heat Pipe for Electric Vehicles in Fast Discharging

This paper presents the concept of a hybrid thermal management system (TMS) including natural convection, heat pipe, and air cooling assisted heat pipe (ACAH) for electric vehicles. Experimental and numerical tests are described to predict the thermal behavior of a lithium titanate oxide (LTO) battery cell in a fast discharging process (8C rate). Specifications of different cooling techniques are deliberated and compared. The mathematical models are solved by COMSOL Multiphysics® (Stockholm, Sweden), the commercial computational fluid dynamics (CFD) software. The simulation results are validated against experimental data with an acceptable error range. The results specify that the maximum cell temperatures for the cooling systems of natural convection, heat pipe, and ACAH reach 56, 46.3, and 38.3 °C, respectively. We found that the maximum cell temperature experiences a 17.3% and 31% reduction with the heat pipe and ACAH, respectively, compared with natural convection.

Thermal Performance of Lithium Titanate Oxide Anode Based Battery Module under High Discharge Rates

A lithium titanate oxide (LTO) anode based battery has high power density, and it is widely applied in transportation and energy storage systems. However, the thermal performance of LTO anode based battery module is seldom studied. In this work, a heat generation theoretical model of the battery is explored. The thermal performance of LTO anode based battery modules under high discharge rates is studied by both experiment and simulation. It is found that the temperature rise of the battery can be estimated accurately with the calculation of the equivalent internal resistance under different discharge rates. In addition, under the same depth of discharge, both the temperature rise and the temperature difference in the battery module increase with the discharge rates.

Thermal Characterizations of a Lithium Titanate Oxide-Based Lithium-Ion Battery Focused on Random and Periodic Charge-Discharge Pulses

Thermal characterization of lithium-ion batteries is essential to improve an efficient thermal management system for lithium-ion batteries. Besides, it is needed for safe and optimum application. The investigated lithium-ion battery in the present research is a commercially available lithium titanate oxide-based lithium-ion battery, which can be used in different applications. Different experimental facilities were used to measure lithium-ion battery heat generation at different operating conditions and charge and discharge rates in this investigation. Isothermal battery calorimeter is the exclusive calorimeter globally, suitable for lithium-ion batteries’ accurate thermal measurements. Pulse charge and discharge in different increments of state of charge were applied to the lithium titanate oxide-based lithium-ion battery to designate the heat generation of the lithium-ion battery cell. Three different cases were studied. The precise effects of different state-of-charge levels and current-rates on lithium-ion battery total generated heat was investigated. The maximum heat generation during 13 A, 40 A, 50 A, 60 A and 100 A pulse discharges were 0.231 Wh, 0.77 Wh, 0.507 Wh, 0.590 Wh and 1.13 Wh correspondingly. It could be inferred that in the case of periodic charge and discharge pulses applied to the lithium titanate oxide-based lithium-ion battery, important parameters including state of charge, current rates, initial cycling, and temperature have a significant influence on total generated heat.

Applying Different Configurations for the Thermal Management of a Lithium Titanate Oxide Battery Pack

This investigation’s primary purpose was to illustrate the cooling mechanism within a lithium titanate oxide lithium-ion battery pack through the experimental measurement of heat generation inside lithium titanate oxide batteries. Dielectric water/glycol (50/50), air and dielectric mineral oil were selected for the lithium titanate oxide battery pack’s cooling purpose. Different flow configurations were considered to study their thermal effects. Within the lithium-ion battery cells in the lithium titanate oxide battery pack, a time-dependent amount of heat generation, which operated as a volumetric heat source, was employed. It was assumed that the lithium-ion batteries within the battery pack had identical initial temperature conditions in all of the simulations. The lithium-ion battery pack was simulated by ANSYS to determine the temperature gradient of the cooling system and lithium-ion batteries. Simulation outcomes demonstrated that the lithium-ion battery pack’s temperature distributions could be remarkably influenced by the flow arrangement and fluid coolant type.