Investigation on enhanced heat transfer characteristics of hybrid convective cooling-phase change material composite systems for battery thermal management

Potential applications of phase change materials for batteries' thermal management systems in electric vehicles

This research contributes to the goal of the cost reduction of vehicle electrification by addressing the thermal management of Lithium-Ion energy storage systems. Lithium-Ion secondary batteries are currently the state of the art for energy storage for vehicle electrification; however, to operate efficiently over their entire lifetime, these batteries must be held in their optimal temperature range. Concurrently, thermal management system cost must be minimized in order to guarantee the economic viability of vehicle electrification. To do so, novel thermal management concepts must be identified and compared to determine the ideal solution. This research presents a method for efficiently and reproducibly comparing diverse battery thermal management concepts in an early stage of development to assist in battery system design. The basis of this method is a hardware-based simulation model of a prismatic Lithium-Ion battery, called the Smart Battery Cell (SBC). The SBC models the thermal behavior of a prismatic automotive cell without the use of active chemistry. By removing the active chemistry, enhanced reproducibility of the experimental conditions is possible and hardware-in-the-loop integration can be realized, allowing for rapid reconditioning between experimental trials. The elimination of active chemistry reduces the safety risks associated with Lithium-Ion cells, making the use of the SBC possible with thermal management systems in an early state of developed, and without costly safety infrastructure. The integration of thermocouples leaves the thermal contact surface undisturbed, allowing the SBC to be integrated into diverse thermal management systems. Eight SBCs are combined to a reference module, as the cell module consisting of multiple cells is the current state of the art in battery system layout. By analyzing the thermal management concepts at module-level, the effects between cells can be observed (versus the analysis of a single cell), and the results from the module-level analysis can be scaled to different battery system sizes. The multifactorial analysis performed at module-level considers not only the thermal performance of the battery thermal management systems, but also the energy consumption, vehicle suitability, production complexity and economic viability. From the analysis, recommendations are made for the development of optimal thermal management systems to facilitate the cost reduction of vehicle electrification.

Lithium-ion batteries are widely adopted as portable energy storage devices due to their high energy capacity and relatively lightweight. Under high-intensity usage, an effective thermal management system is essential to control battery pack temperature within the desired range to guarantee battery safety and ensure a proper life cycle. This study developed a pulsating heat pipe (PHP) based thermal management system to promote battery temperature control. The system was tested for a large battery pack (2 kWh) under mild and severe ambient conditions via ANSYS Fluent simulation. A sensitivity study identified optimal PHP dimensions regarding the battery pack. The performance of PHP for both small and large scales was also evaluated. The system's effectiveness was compared to classical battery thermal management (BTM) systems such as forced air cooling, sidewall water cooling, and traditional heat pipes. The results demonstrated that the developed PHP-based passive cooling system effectively controls temperature, saves space, and reduces power consumption.

This chapter aims to describe the impact of vehicle electrification on the different thermal management systems. The first section of the chapter recalls the classification of hybrid and fully electric vehicles. The second section addresses the impact of electrification on the cabin climate control. Reversible heat pump systems are key components to cover both cabin cooling and heating loads, while limiting the vehicle driving range decrease. Different architectures of heat pumps, using different heat sources and heat sinks, are discussed. The last section covers battery thermal management as well as e-motors and power electronics cooling. Finally, the thermal management of the hybrid or electric vehicle as a whole is discussed. This last section aims at showing the benefit of integrating all thermal energy management systems in a way to increase the energy performance of the vehicle.

A review of power battery thermal energy management

Thermal performance analysis of 18,650 battery thermal management system integrated with liquid-cooling and air-cooling

Assessment method of the integrated thermal management system for electric vehicles with related experimental validation

Experimental investigation of longevity and temperature of a lithium-ion battery cell using phase change material based battery thermal management system

In the development and validation of complex systems such as energy management for Battery Electric Vehicles (BEVs), important figures are driving cycle patterns and the frequencies and durations in the change of environmental conditions. The change in the environmental conditions directly leads to the activiation and deactivation of event-chains to control the flow of energy and the conditioning of energy storage. Starting with the design of these systems, it would be beneficial to include also timing and the variance in timing of changing conditions. To reflect different occurrence rates, Markov modelling can be used. In system reliability engineering statistical Markov analysis is well understood. Recently, the three-dimensional Stochastic Markov chain modeling was published, which aims to optimize energy management by predicting driving behavior. However, all these approaches stick to the limitations of Continous Time Markov Chains (CTMC). The usage and change of conditions of thermal energy management systems in electric vehicles does not strictly obey the Markov properties. Overcoming the Markov properties, in this paper it is presented how various timing characteristics by using different propability functions can be used in modeling. With this, it is possible to model different occurrence types and durations of changing conditions, reflecting their type of frequency and distribution. With different types of modeling elements and a case study we demonstrate the modeling approach. The resulting model can be interpreted as a stochastic source for a Semi-Markov process. This allows for further analysis such as the derivation of indicators about reliability.

Contemporary nano enhanced phase change materials: Classification and applications in thermal energy management systems

Transient thermal management of laser systems using Plate-Fin phase change heat Exchangers: Experimental and computational study

Lithium ion (Li-ion) batteries are low cost and have a high energy density and a small volume. Thus, battery packs comprised of multiple Li-ion batteries have become the dominant energy source for electric vehicles (EV) and hybrid electric vehicles (HEV), and have contributed to their current popularity, as has fast-charge technology, which is also used in EVs and HEVs. However, due to the high power requirement of EVs and HEVs under high-speed operating conditions or fast charging conditions, Li-ion battery packs suffer from high temperatures if no appropriate thermal management system is installed, leading to battery performance degradation and even thermal runaway [1]. The energy efficiency, safety, and life of power batteries, such as lithium-ion batteries, are very sensitive to temperature, and the performance and stability of Liion batteries are reduced in the abnormal temperature range [2]. The temperature change of batteries is usually inevitable because they are affected by environmental conditions and release heat by a series of chemical reactions during charging and discharging. Therefore, it is essential to develop a smart thermal management system that maintains the proper temperature range for power batteries. In this talk, key technologies for a smart thermal management system of power batteries for electric vehicles and energy storage system will be presented. The key technologies are based on our recent findings that utilize multiscale micro/nanostructured surfaces for integrated wicks [3]. These surfaces manipulate the nucleation site density that controls the heat transfer coefficient and critical heat flux for the evaporator of a heat spreader [4, 5]. The multiscale micro/nanostructured wick design and micro/nano multiscale structure fabrication techniques are crucial for controlling the capillary flow and evaporation that improve the effective thermal conductivity of the thermal management system for power batteries. We presented a novel technique for the thermal management of power batteries utilizing ultrathin heat spreaders. Temperature significantly affects the energy efficiency, safety, life, and performance of a lithium-ion battery pack in electric vehicles (EVs). Therefore, controlling the temperature of the battery pack within a certain range has become a challenge in the development of EVs, especially in fast charging with high charge rates (C-rates). An ultrathin thermal ground planebased battery thermal management system was developed, which utilized 0.4 mm thick ultrathin thermal ground planes and cooling fans as a heat sink. The thermal performance of the novel battery thermal management system was experimentally investigated at 2.2 C to 4 C FC regimes under environmental temperatures from 10 ℃ to 50 ℃. The battery thermal management system was able to maintain a mean surface temperature of 55Ah lithium iron phosphate (LiFeO_4, LFP) batteries below 42.7 ℃ even at a 4 C charge rate and achieve good surface temperature uniformity in all cases. At an ambient temperature as high as 50 ℃, the battery thermal management system can still maintain the mean battery surface temperature under 57.3 ℃. The temperature rise, temperature uniformity, and thermal resistance gained improvements of up to 23.3%, 28.4%, and 62.6%, respectively, compared to a battery thermal management system with the same dimensions as copper heat spreaders. The effects of different pores densities of the mesh in the ultrathin thermal ground plane were also studied. The battery thermal management system showed brilliant performance in controlling the temperature of the battery pack, which was capable of being a viable solution for high-power battery thermal management in EVs.

The lithium-ion battery is considered the primary power supply source for electric vehicles due to its high-energy density, long lifespan, and no memory effect. Its performance and safety highly depend on its operating temperature. Therefore, a battery thermal management system is necessary to ensure an electric vehicle (EV)’s performance. Air as a cooling medium is still used in a wide range of thermal management system applications, owing to its low-cost and lightweight. However, the conventional air-based cooling strategy shows an insufficient heat dissipation capacity and usually fails to block the thermal runaway propagation between batteries. Thus, it is of great importance for improving the heat dissipation of an air-based thermal management system. In this paper, three novel schemes (schemes B, C, and D) are introduced successively based on enhancing the heat transfer capacity and safety of a battery pack under a thermal runaway condition. Schemes B and C introduce a hollow spoiler prism and a spoiler prism filled with phase-change material with fins, respectively. The cooling effects of the three schemes are compared using computational fluid dynamics technology. The models of all the schemes are 3D symmetrical structures. In the CFD model, the battery heat-generating sub-model is incorporated through a user-defined function. The results indicate that all three schemes reduce the maximum temperature and the maximum temperature difference in the pack effectively compared with the conventional air cooling system. Scheme D presents the best cooling performance and hinders the propagation of the TR between adjacent batteries under a TR condition. The paper may provide a feasible method for improving the performance of an air-cooled thermal battery management system.

Due to the extreme sensitivity of temperature in Li‐ion batteries, thermal management is a significant issue that must be addressed. Since the battery in electric vehicles produces an enormous amount of heat, it reduces its efficiency and its performance. Currently, there is a need for electric vehicles (EVs) because conventional IC engines produce an enormous amount of pollution which affects the environment, so an electric vehicle produces a very small amount of pollution. It is now being recommended and used by many people. But the electric vehicle faces some major problems due to overheating in their battery module. Nowadays, battery temperature is regulated by a system called battery thermal management system (BTMS). Modern EVs use active and passive cooling systems. Thermal management tries to improve battery architecture for greater autonomy or quick charging. To meet future difficulties in thermal management, such as air or liquid cooling, are needed. As a result of the battery's overheating, the vehicle's performance, power, energy storage, charging, and discharging are all negatively impacted; hence, a reliable thermal management system for the battery is essential for resolving these problems. This study provides an overview of the BTMS of the future, beginning with the problems involving temperature and safety. The following is a list of the benefits and drawbacks of BTMSs, which are used to maintain acceptable temperatures for battery packs. In conclusion, an analysis of the progress made in developing temperature management systems for future batteries is presented. As a first look at potential BTMSs for locomotive applications, it has been proposed to conduct a comprehensive analysis and classification of both existing and potential battery management systems.

Liquid hydrogen storage, thermal management, and transfer-control system for integrated zero emission aviation (IZEA)