Thermal Management Of Li-ion Batteries Research Articles

Liquid cooling plate with drop-shaped deflectors based on Coanda Effect - For Li-ion battery thermal management

Battery thermal management system (BTMS) can maintain the operating temperature and temperature difference of Lithium-ion batteries (LiBs) within the ideal range. In this paper, three kinds of liquid cooling plates with mesh structures (LCP-MSs) were proposed, and they were compared with the LCP with straight channel (LCP-SC). The results show that the LCP-MSs can effectively improve the temperature uniformity of the LiB and reduce the heat concentration. Among the three proposed LCP-MSs, the LCP with drop-shaped deflectors (LCP-DD) is particularly outstanding in reducing the pressure drop (∆P) of coolant. At the same time, in terms of cooling performance, the gap between LCP-DD and the other two LCP-MSs is very small. To further study the cooling performance and ∆P of LCP-DD, structural parameters, number of deflectors, layout of deflectors, and inlet velocity were investigated. The results show that the heat dissipation performance of LCP-DD was improved with the increase of the deflector size/number and the inlet velocity, while ∆P shows an increasing trend. Finally, the orthogonal test was carried out to optimize the design of the proposed LCP-DD. The optimal solution can control the maximum temperature, maximum temperature difference and pressure drop at 301.3 K, 3.1 K, and 251 Pa, respectively.

Experimental study of Li-ion battery thermal management based on the liquid-vapor phase change in direct contact with the cells

Experimental study of Li-ion battery thermal management based on the liquid-vapor phase change in direct contact with the cells

Design optimization of Air-Cooled Li-ion battery thermal management system with Step-like divergence plenum for electric vehicles

Air-cooled Battery Thermal Management System (BTMS) technology has been proven and is frequently employed to regulate the distribution of temperature in a battery pack of an electric vehicle. In this study, a step-like divergence plenum was introduced to a standard Z-type BTMS to alter its airflow distribution pattern and thus improve its cooling effectiveness. The impacts of the number and length of steps in the divergence plenum on the cooling responses of the BTMS were investigated using a validated Computational Fluid Dynamics (CFD) method. Analysis of 1-step, 3-step, 4-step, and 7-step BTMS models were conducted and findings showed that the step quantity has a significant impact on the battery pack's ability to dissipate heat. For a step length of 30 mm, a 7-step case model offered the best system’s maximum temperature of 324.9 K and cell temperature difference of 1 K which were both 3.94 K and 5.93 K, respectively lower than that of the standard Z-type model. Furthermore, the step case models were optimized by observing the impacts of their step length on system's thermal performance. The outcomes showed that there was a substantial impact of the step length on cooling performance for all case models. For instance, a 4-step case model with a 45 mm step length offered a reduction in maximum temperature of 3.61 K and maximum temperature difference of 6.01 K when compared to the standard Z-type model. Finally, the behaviour of each case model was examined under increasing inlet air velocity and it shows that at higher airflow velocity, the 7-step case model performed substantially well than other investigated cases.

Liquid-cooled cold plate for a Li-ion battery thermal management system designed by topology optimization

Liquid-cooled cold plate for a Li-ion battery thermal management system designed by topology optimization

Thermal Management Analysis of Proton Exchange Membrane Fuel Cell Filled with Phase Change Material in Cooling Channel

Passive thermal management using a phase-change material (PCM) for proton exchange membrane fuel cells (PEMFCs) has been proposed and widely used in the thermal management of Li-ion batteries. A three-dimensional and nonisothermal numerical model of a PEMFC with a PCM cooling channel (PCC) is established in this study. The PCC is better than an air-cooling channel (ACC) in terms of reactant distribution and water removal. Its temperature at the interface of the gas diffusion layer and catalyst layer is lower, and the uniformity of temperature is better. The peak current and power density of the PCC are 4.60% and 5.14% higher than those of the ACC, respectively. Furthermore, the PCC does not increase parasitic power, unlike the ACC. In addition, owing to the high temperature near the outlet, the cooling effects of filling 1/3 PCM and filling 2/3 PCM near the outlet and filling of all PCM are investigated, which shows that the filling of 2/3 PCM provides a better cooling performance.

Numerical study on ultrathin wide straight flow channel cold plate for Li-ion battery thermal management

Complex channel can enhance heat transfer performance of cold plate. Therefore, until now the research on straight channel cold plate used in Li-ion Battery Thermal Management System (BTMS) is very few, in which narrow straight channel is focused on. However, pressure drop of straight channel is much lower than of complex channel. Thus, an ultrathin Wide straight flow channel Cold Plate (WCP) is designed, investigated and compared with representative complex channel cold plates based on a novel parameter total inlet driving force instead of commonly used mass flow rate. Results indicates WCP shows excellent comprehensive performance. Compared with Serpentine, Bifurcated and U-turn channel cold plates, the maximum temperature of WCP decreases by a maximum of 4.31 K, 19.31 K, 45.50 K, respectively, while the standard deviation of temperature of WCP decreases by a maximum of 47.51 %, 45.40 %, 65.08 %, respectively. The better performance of WCP is achieved with less power consumption. Besides, WCP with lateral channel and wide channel width shows better performance than WCP with longitudinal channel and narrow channel width. Considering the processing difficulty of WCP is obviously lower than that of complex channel, if ultrathin WCP is popularized, the performance of BTMS can undoubtedly be significantly improved.

Thermal management of Li-ion battery by using active and passive cooling method

To enhance the safety of Li-ion batteries, it is crucial to understand their behavior when exposed to high temperature. The structural arrangement and identical cell spacing are key aspects related to safety of Li-ion batteries. In this study a series of charge and discharge experiments on battery packs were carried out to evaluate the effects of thermal management on the performance of the battery pack. The temperature distribution among the cells was analyzed by varying surrounding conditions and using phase change material to improve thermal management. The general charging discharging patterns of cell shows the temperature difference as high as about 10 °C as compared with ambient temperature when no thermal management was employed, which ultimately reduce the cell performance with time on long term use. Active cooling (Air cooling) improves the thermal management inside the battery pack showing the temperature difference of about 6 °C as compared with ambient temperature. Whereas passive cooling significantly improves the thermal management inside the battery pack showing temperature difference of about 3.5 °C as compared to ambient temperature, which shows that the thermal management of battery pack using PCM can be a veritable method to enhance the battery pack life and safety.

Effect of Different Inlet/Outlet Port Configurations on the Thermal Management of Prismatic Li-Ion Batteries

Abstract The performance and life cycle of Li-ion batteries are governed by the maximum temperature and uniformity of temperature distribution in the battery pack, and an efficient thermal management system is highly desired to keep the operating temperature of the battery pack within safe operating limits. Air cooling has received extensive attention in the area of battery thermal management. However, performance intensification of air-cooling modules is essential while keeping the simplicity of design to satisfy the weight and space constraints of electric vehicle (EV) applications. In the current work, efforts have been made to design a simple and generalized air-cooling module for efficient thermal management of Li-ion batteries. The current work explored the effect of two common air flow configurations: side inlet and side outlet (SS) and side inlet and front outlet (SF), with different number of inlet/outlet ports (single inlet and single outlet, single inlet and two outlets, two inlets and single outlet, and two inlets and two outlets) on the thermal and hydraulic performance of Li-ion battery pack. Subsequently, a new design of battery module with an open outlet port is proposed. It is observed that the way fluid leaves the cooling module significantly influences the flow and temperature distribution uniformity of the battery pack. Significant improvement in the fluid flow distribution and lower temperature fluctuation are maintained by the SF designs as compared to the SS designs. Among all SS designs, only SS-Ib at Vin ≥ 5.6 m/s and SS-IV at Vin ≥ 4.8 m/s are found suitable for the thermal management of Li-ion battery pack, whereas all SF designs maintained desired Tmax and ΔTmax conditions at Vin ≥ 4.8 m/s. Furthermore, the new design (SF-V) with an open outlet results in the reduction of Tmax by 7 °C and ΔTmax by 64.5% as compared to base design (SS-Ia) at the same pressure drop penalty.

Study the thermal management of Li-ion batteries using looped heat pipes with different nanofluids

The production of electric vehicles and their accessories is grooming day by day in the automotive industry. The heart of these electric vehicles is the power source, which is known as batteries. The capacity and performance of such batteries demand a high rating, due to the customer's need and improved vehicle features. Unfortunately, the batteries are facing thermal failures caused by the poor thermal management approach. Li-ion batteries are the most familiar ones which have a very high energy density compared to others. But, these batteries lead to the breakdown of ions and lithium plating because of the fluctuation in temperature distribution and fast charging characteristics. The temperature distribution varies with respect to loading and application. However, this process is accompanied by thermal runaway, which may result in the fatal destruction of batteries. To overcome such issues, the present work selected looped heat pipes (LHP) as a device to transfer the excessive temperature on batteries using nanofluids. Water, Ethylene glycol and acetone were selected as working fluids along with graphene oxide (GO) Nanoparticles. The experiment is conducted for a constant heat input of 30W and various filling ratios (20%, 35%, 50%, 65%). Stability, thermal conductivity, thermal resistance and temperature distributions are discussed. The experiment results are validated with Computational fluid dynamics.

Numerical study of PCM thermal behavior of a novel PCM-heat pipe combined system for Li-ion battery thermal management

A three-dimensional numerical model is developed and validated against experimental data for a cylindrical lithium-ion battery module with a compact hybrid cooling system of phase change material (PCM) and heat pipes. This cooling system is particularly well-suited for small or medium-sized battery module or pack. The PCM process and its effect on battery thermal behavior are numerically investigated for cases based on different C-rate discharge processes (0.5C, 1C and 2C), different PCM properties (different mass fractions of expandable graphite) and different charge–discharge cycles of the battery module. The results indicate that the PCM liquid fraction distribution is not uniform during the discharge process, the PCM starts to melt from its outermost neighboring the batteries and its upper part gets more liquid due to natural advection of liquid PCM. The different melting rates within the PCM lead to slightly enlarged temperature difference between batteries. Increasing discharge C-rate further accentuates this temperature difference. A tested composite PCM of 12 wt% EG (expanded graphite) shows better heat dissipation performance than that of pure PCM, and consequently it is better suited for battery thermal management systems. The simulations for different charge–discharge cycles indicate that lowering C-rate and increasing recovery time can improve thermal performance of the battery module and thermal control is thus more effective.

Theory and Practices of Li-Ion Battery Thermal Management for Electric and Hybrid Electric Vehicles

This article surveys the mathematical principles essential for understanding the thermal management of Li-ion batteries, the current technological state of the art, and the solution. Since the thermal management of electric drive vehicles has environmental, economic, and safety impacts, this review focuses on the efficient methods of battery thermal management (BTM) that were proposed to overcome the major challenges in the electric vehicle industry. The first section examines the perspective of battery-driven vehicles, the principles of Li-ion batteries with a thermal runaway, and their implication for battery safety. The second section discusses mathematical approaches for effective BTM modeling, including the thermal-fluidic network model, lumped capacitance model, spatial resolution lumped capacitance model, equivalent circuit model, impedance-based model, and data-driven model. The third section presents the current state-of-the-art technologies, including air-based, liquid-based, PCM-based, in situ BTM methods, and heat pipe and thermoelectric module-based methods. The conclusion section summarizes the findings from existing research and the possible future directions to achieve and employ better thermal management techniques.

Unification of intensive and extensive properties of the passive cooling system under a single envelope for the thermal management of Li-ion batteries

Vehicle electrification can pave the way towards zero emission transport sector, provided renewable sources fulfil the major stakes of the electricity demand. While pushing this technology for a global scale implementation, several performance hurdles of the electric vehicle (EV) power unit are to be overcome. Many of the predicaments arise due to the negative sensitivity of Lithium-ion battery performance to elevated working temperatures. For the seamless operation of EVs in a hot climate, we examine a novel passive cooling system in this study. This cooling system features two distinct types of heat extraction media: a) PCM based isothermal storage-based heat sink and b) fin based augmented thermal transport-based heat sink. These two sub-components are investigated in mutually competitive and complementing scenarios to understand the relative contributions of each component in heat extraction and realize the maximum cooling potential achievable from a combined implementation. We analyse on a case-by-case basis the variations in the different heat extraction modes arising due to intensive material properties such as thermal diffusivity and extensive properties such as retrofit dimensions. Comparison of heat rates for the two cooling mechanisms shows that PCM and fin sub-components share a mass ratio (MR) and length ratio (LR) of 0.8 and 1, respectively, in their combined operation to achieve maximum cooling of 142.1 W. A maximum temperature drop of 29.3 K could be realized with the proposed passive cooling system, which is sufficient to maintain a favourable operating temperature for the EV power unit in a hot climate. A new index, VSR has been introduced based on non-dimensional input parameters. Finally, this study develops a set of two correlations that can be used to estimate the thermal performance of a battery pack with different retrofit materials and design variables.

Numerical analysis of pressure drop and heat transfer of a Non-Newtonian nanofluids in a Li-ion battery thermal management system (BTMS) using bionic geometries

In the total efficiency of the systems employed in these devices, efficient cooling techniques in thermal management of lithium-ion battery (LIB) systems have been extremely significant problems. To decrease the temperature of the battery pack system (BPS) during operation, these cooling methods should be cost-effective and low-consumption. In this study, a plate LIB is investigated. The LIB pack consists of several cells. In this study, paths of the nanofluids (Nfs) are placed on the right and left sides of each cell for the cooling process. Non-Newtonian nanofluid (NN-Nfs) flows in embedded channels modeled using natural bionic systems. In this study, the thermal behavior of the LIB is investigated. For this purpose, the finite element technique and COMSOL software is used to solve the governing equations of the Nfs flow and the LIB. The results show that the addition of nanoparticles (NPs) to the base fluid reduces the thermal resistance of the cooling system and enhances the temperature uniformity at the LIB surface. The increment in fluid velocity has the same effect. Also, enhancing the velocity and volume percentage of NPs reduces the maximum LIB temperature. An increment in the inlet velocity from 0.01 to 0.05 m/s enhances the amount of pumping power by 12.62 and 14.53 times, respectively, for water and nanofluid with the volume fraction of 3%. The maximum enhancement in heat transfer coefficient, which is equal to 14%, occurs by adding 3% NPs at a velocity of 0.01 m/s compared to the pure fluid under the same conditions.

Shape-stable and fire-resistant hybrid phase change materials with enhanced thermoconductivity for battery cooling

Thermal safety issues related to the thermal runaway problems in Li-ion batteries have been greatly concerned due to their wide applications. In this study, a low-cost and facile strategy for Li-ion battery thermal management was enabled by packing hydrated salt into organic paraffin and further stabilization of the composite by adsorption into a porous supportive material (expanded graphite, EG). The resultant composite phase change material (HPC@EG) demonstrated good shape stability and enhanced thermal conductivity (TC, 1.53–4.35 W m−1 K−1 at EG loadings of 5–15 wt%). HPC@EG also exhibited high latent heat (196.6 J/g) with sustained thermal storage performance over at least 500 heating / cooling cycles. The favorable performance of HPC@EG resulted from the paraffin acting both as a sealant and nucleating agent for the hydrated salt and as a co-phase change material, and the contribution of EG to the shape-stability and thermal conductivity. An added advantage of using hydrated salt and EG was their intrinsic fire-resistance which was also inherited by the HPC@EG composite. Such a combination offered effectiveness in preventing overheat of Li-ion batteries as we demonstrated, showing great promise in Li-ion battery thermal management in respect of price, safety and the cooling performance.

Lauric acid encapsulated in P-doped carbon matrix with reinforced heat storage performance for efficient battery cooling

Driven by the growing of electric vehicle, there is an urgent need to develop efficient thermal management of Li-ion battery. Promising phase change materials (PCMs) supported on carbon supports, especially nitrogen doped porous carbon, work efficiently to cool battery with reinforced heat storage performance. In this research, P-doped porous carbon via phosphorization of ZIF-67 (P/ZIF-C) was utilized to encapsulate lauric acid (LA) and form PCM composite. P-doping can improve structure porosity and percentage of pyridinic N in ZIF-C, both of which work to enhance LA loading content, heat transfer and shape-stability of the PCM composite. Consequently, LA@P/ZIF-C exhibits higher loading content (80%), enhanced thermal conductivity (1.05 mW/K) and shape-stability (10 °C above m.p.) comparing with LA supported on ZIF-67 derived carbon. The LA@P/ZIF-C composite worked efficiently to reduce temperature of working battery by 10% and enhance discharge capacity by 20%, which show great potential in thermal management of electric vehicle battery.

Spider Web-Inspired Graphene Skeleton-Based High Thermal Conductivity Phase Change Nanocomposites for Battery Thermal Management

HighlightsA three-dimensional spider web-inspired structured graphene skeleton is constructed.The spider web-like skeleton endows paraffin wax with a significantly high longitudinal and transverse thermal conductivity enhancement of ~1260% and ~840%, respectively, at 2.25 vol% skeleton.The resultant composites exhibit outstanding performance on the thermal management of Li-ion batteries.

Laser wobble welding of fluid-based cooling channel joining for battery thermal management

Aluminium alloys are increasingly used to fabricate cooling channels for the thermal management of Li-ion batteries. Cooling channel fabrication involves a number of manufacturing operations including material extrusion, forming and joining/welding. In general, welding of aluminium alloys is challenging as they are both highly reflective and thermally conductive. To address the joining challenges, this paper is focused on developing an optimised joining process to connect a thin, flanged cooling channel to the thick module manifold of the battery thermal management system to create a watertight joint with high mechanical strength. As continuous seam welding was required, laser welding was the preferred as it is a non-contact process combining high speed and precision. For this application, 0.4 mm Al cooling channel was welded with 1.5 mm Al endplate/module manifold using a wobble head integrated with 1 kW CW fibre laser system. The effect of process parameters including line energy, incident angle, laser power, welding speed and beam offset were investigated to optimise both the weld geometry and strength. Microstructure, micro-hardness and grain formation analyses were carried out to understand the metallurgical behaviour of the weld. Beam offset had the most significant effect on the responses such as weld strength, throat thickness and modified throat thickness, and laser power had a significant influence on two key geometric features of the fusion zone, i.e. penetration depth and weld width. Weld strength was optimised using a developed surrogate model and a maximum load of 646.89 N was achieved using 0.2 mm beam offset, 331.82 W laser power and 659.10 mm/min welding speed. Using this optimum combination, a leak-proof cooling channel and module manifold joint were produced for battery thermal management.

Battery thermal management based on multiscale encapsulated inorganic phase change material of high stability

• An effective method to prevent dehydration and improve stability of inorganic PCM. • Applies a nonflammable inorganic PCM for battery thermal management. • Inorganic PCM has a large thermal conductivity, small subcooling and high stability. • Inorganic PCM shows better cooling performance in a battery pack than organic PCM. This paper proposes a battery thermal management system with an inorganic phase change material(PCM). A multiscale encapsulation method is presented to solve the inherent problems of the inorganic PCM-sodium acetate trihydrate (SAT)-Urea. This method adopts microscale encapsulation with expanded graphite (EG) to enhances the thermal conductivity of the PCM to 4.96 W/m·K and eliminates the liquid leakage. Further macroscale encapsulation with the organosilicon sealant significantly improves the long-term stability of the salt hydrate, because it completely cuts off the dehydration channel of the salt hydrate, maintaining a stable composition in the PCM. This effective multiscale encapsulation paves the way of applications of the inorganic PCMs in Li-ion battery thermal management. This inorganic PCM is compared with an organic PCM in the fire resistivity and cooling performance for a 20-cell battery pack. The results confirm that the inorganic PCM is safer because it is not flammable and offers a cooler but a more uniform thermal environment for the battery. The competitive inorganic PCM owns advantages in price, safety and cooling performance, showing great prospects in commercial battery thermal management systems.

Investigation of the Applicability of Helium-Based Cooling System for Li-Ion Batteries

This paper proposes a novel He-based cooling system for the Li-ion batteries (LIBs) used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). The proposed system offers a novel alternative battery thermal management system with promising properties in terms of safety, simplicity, and efficiency. A 3D multilayer coupled electrochemical-thermal model is used to simulate the thermal behavior of the 20 Ah LiFePO4 (LFP) cells. Based on the results, He gas, compared to air, effectively diminishes the maximum temperature rise and temperature gradient on the cell surface and offers a viable option for the thermal management of Li-ion batteries. For instance, in comparison with air, He gas offers 1.18 and 2.29 °C better cooling at flow rates of 2.5 and 7.5 L/min, respectively. The cooling design is optimized in terms of the battery’s temperature uniformity and the battery’s maximum temperature. In this regard, the effects of various parameters such as inlet diameter, flow direction, and inlet flow rate are investigated. The inlet flow rate has a more evident influence on the cooling efficiency than inlet/outlet diameter and flow direction. The possibility of using helium as a cooling fluid is shown to open new doors in the subject matter of an effective battery thermal management system.

Effects of micro heat pipe arrays on thermal management performance enhancement of cylindrical lithium‐ion battery cells

The performance of lithium-ion (Li-ion) batteries in a battery module is significantly affected by the operating temperature. Temperatures above 40°C can speed up the battery aging and shorten the lifespan and may even lead to thermal runaway. Besides, the maximum temperature deviation between the cells inside the battery module is normally expected to be less than 5°C. Among various cooling strategies used in thermal management of Li-ion batteries, application of micro heat pipe arrays (MHPAs) has received little attention. Hence, in the present study, a feasibility study has been conducted to assess the thermal performance of such a thermal link in controlling both the maximum temperature and temperature dispersion within the desired range. The MHPA-assisted cooling system was tested under various rates of heat generations (10-25 W total) and degrees of inclination (−90° to +90°). Experimental results have revealed a significant influence of the MHPA angle of inclination on the temperature of the evaporating section of the heat pipe. The best thermal performance was found to be at an angle of inclination of −15° where the condenser is located above the evaporating section. Performance degradation was observed for all the MHPA orientations where the condenser is located below the evaporating section. The thermal performance of the MHPA-assisted cooling system is also influenced by the rate of generated heat. The maximum effective thermal conductivity for the MHPA was measured to be about 75 000 W/m2 °C. A dimensional figure of merit is defined for the MHPA-assisted cooling system.