Forced Air Cooling Research Articles

Silicon dioxide-enhanced composite phase change materials for the thermal management of retired lithium-ion batteries

Lithium-ion batteries (LIBs) have been regarded as the hearts of electric vehicles (EVs). However, the thermal safety of LIBs is considered to be a common and crucial technical issue, especially for large-scale retired LIBs. In this study, a novel composite phase change material (CPCM) based on paraffin (PA)/cubic boron nitride (CBN)/silicon dioxide (SiO2) was proposed and further utilized for decommissioned battery modules. First, CPCMs with different SiO2 ratios were prepared by employing a physical mixing melting method. Then the effects of different ratios of SiO2 on the thermal properties, thermal conductivity, thermal stability, mechanical strength, electrical insulation properties, and flow properties of the CPCMs were studied from macroscopic and microscopic perspectives. Eventually, the CPCM possessing 5 % SiO2 was used in the battery module for thermal management evaluation. The corresponding results indicated that even under the severe conditions of high temperature (40 °C) and a 1.5C higher discharge rate uninterrupted charge–discharge cycle, the maximum temperature and maximum temperature difference of the CPCM battery module were reduced by 8.45 and 5.40 °C, respectively compared with forced air cooling (FAC). This outcome can provide fundamental data and theoretical support for the thermal management strategy and thermal safety improvement of high energy density power systems.

Forced Air Cooling for Battery Module on Series Connected Batteries: Temperature Variation Due to Non-Uniform Flow Across Channel

Cells in battery pack for electric vehicle are typically connected in series to meet system voltage requirement. In series connection, each cell will experience identical amount of current drawn, therefore the amount of heat generation for each cell will be relatively similar. Nevertheless, this depends on the cell internal resistance which causes joule heating. To mitigate increase in temperature in the pack, cooling system is necessary. Forced air cooling is the most straightforward cooling system as it pulls cool air from inside the vehicle cabin, and the air will be channeled through cooling routes in the battery module. Typically, the cell located close to the inlet of the cooling system gets the maximum cooling rate, and the cooling capacity reduces as air passes towards the last cell in the module. Two cooling designs are explored in which air velocity is varied by changing the cross-sectional area of inlet air whilst keeping the same mass flow rate. This causes the inlet air velocity to change, to which the airspeed for a small air inlet will be higher than a larger inlet. It shows that higher air speed promotes better cooling only at the first and last cell in the module with a temperature gradient up to 15°C. A battery module with a higher cross-sectional area provides a more uniform heat transfer rate whereby the individual cell temperature is relatively similar with 50% more consistent than the smaller cross-sectional area. This demonstrates that having a higher air speed is not the key attribute in determining the cooling factor of a battery module/pack.

Numerical Investigation of the Thermal Performance of a Hybrid Phase Change Material and Forced Air Cooling System for a Three-Cell Lithium-Ion Battery Module

The thermal performance of a lithium-ion battery module comprising three cells contained within a casing was investigated at discharge rates of 3C and 5C with three different cooling strategies: forced air, phase-change material (PCM), and a hybrid system using a combination of forced air and the PCM. Three levels of fan speed (5000 rpm; 7000 rpm; and 9000 rpm) for cooling air flow were considered. A numerical simulation of heat transfer was performed using the ANSYS Fluent software. The electrochemical modelling of a battery was developed based on the NTGK approach, and the phase-change phenomenon was treated as an enthesis–porosity problem. The composite PCM, aluminum metal foam embedded in n-octadecane, had better heat dissipation performance than forced air convection. The PCM is significantly more effective at heat dissipation than forced air. Interestingly, when using a hybrid cooling system that combines forced air and a PCM, although it meets the operational requirements for Li-ion batteries in regard to maximum temperature and temperature uniformity at a 3C discharge rate, the airflow appears to have a negligible effect on thermal management and yields an indiscernible change in temperature. This can be attributed to a complex flow pattern that developed in a casing as a result of the suboptimal design of the inlet and outlet. Further studies will be required for the optimal positioning of the inlet and outlet, as well as the effectiveness of combining liquid cooling methods.

Thermal management for the 18650 lithium-ion battery pack by immersion cooling with fluorinated liquid

In this work, a new battery thermal management system (BTMS) utilizing a SF33-based liquid immersion cooling (LIC) scheme has been proposed. Firstly, the comparative investigation focuses on the temperature response of the LIC and forced air cooling (FAC) modules in different scenarios. The results demonstrate that LIC module effectively mitigates heat accumulation, thereby presenting notable advantages in terms of temperature control and equalization, even though the LIC module works under the stage without phase change occurrence. During 2C and 3C charging, the highest temperatures of the LIC module are observed to be 10 °C and 19.1 °C only lower than those of the FAC module, respectively. Furthermore, the highest temperature differences of the LIC module are only 12.89 % and 8.57 % of the corresponding values exhibited by the FAC module. Moreover, the associated cooling energy consumption for the LIC module is greatly reduced, amounting to only 16.47 % and 43.76 % of that required by the FAC module. Subsequently, an active control scheme for the LIC is initially proposed, and the phase change process of the LIC under various discharging rates is recorded and analyzed using a high-speed camera. This study serves as a preliminary proof of concept for the feasibility of SF33-based LIC scheme in BTMS.

Experimental investigations of liquid immersion cooling for 18650 lithium-ion battery pack under fast charging conditions

In this study, a novel battery thermal management system (BTMS) based on FS49 is proposed and tested for cooling the cylindrical lithium-ion battery (LIB) module under fast charging conditions. Firstly, the temperature response of the battery module under 2 C and 3 C rates charging with forced air cooling (FAC) and liquid immersion cooling (LIC) is compared. The results indicate that the LIC has excellent heat dissipation performance, and the peak temperature of the module during 2 C and 3 C rates charging are reduced by 7.7 °C and 19.6 °C, respectively, compared with the FAC, while the corresponding cooling energy consumption of LIC is only 14.41% and 40.37% of the FAC. Meanwhile, the LIC embraces the advantages of minimizing the temperature non-uniformity in battery pack. The corresponding peak temperature difference of the module is just 1.1 °C and 1.2 °C, which is only 17.7% and 11.6% of that under FAC. Subsequently, the thermal management performance of the proposed LIC is investigated under conventional C rate discharging and different fast charging schemes. Finally, effect of condenser flow rate and cooling water temperature were investigated. This study demonstrates the application prospect of the LIC in the field of LIB fast charging.

Experimental and Numerical Investigations of a Thermal Management System Using Phase-Change Materials and Forced-Air Cooling for High-Power Li-Ion Battery Packs

The thermal management system of a power battery is crucial to the safety of battery operation; however, for the phase-change material (PCM) thermal management system of a battery, the thermal cycling of phase-change material under large discharge rate conditions will lead to thermal conductivity degradation and thermal stress problems. A method of manufacturing PCM containers with metal fins to package pure phase-change material is put forward to solve the problem. The system temperature under different conditions is studied using numerical and experimental methods. A thermal resistance model is built to analyze the thermal transfer performance of PCM containers with fins. The results show that the PCM container structure can effectively control the battery temperature within the suitable temperature range under the low discharge rate, but the maximum temperature of the battery pack at the high discharge rate of 3 C will exceed the optimum operating temperature range. Adding fins can reduce the maximum temperature and improve the system temperature uniformity. By combining fins with forced-air cooling, the maximum temperature and maximum temperature difference of the battery pack at a high discharge rate can be effectively reduced.

Experimental investigation and comparative analysis of immersion cooling of lithium-ion batteries using mineral and therminol oil

Renewable energy can potentially mitigate the adverse effects of energy and environmental crises. The Lithium-ion battery, a storage system investigated in the present study, has a potential to increase the penetration of renewable energy technologies, due to its high mass and volumetric energy density. However, thermal management strategies are necessary for lithium-ion battery electrical storage to grow technologically and gain widespread acceptability. In the present work, a comparative study of the different cooling methods, namely, forced air cooling (FAC), direct liquid contact cooling (i.e., Mineral oil cooling (MOC), and therminol oil cooling (TOC)) with low-cost coolants have been carried out on 20 cells of 10Ah lithium-ion battery-stack at a discharge rate of 1C, 1.5C, 2C, 2.5C, and 3C. It is found that the maximum temperature of the battery module is reduced by 43.83%, 49.17%, and 51.54% for forced air cooling, therminol oil cooling, and mineral oil cooling respectively, at 3C discharge rate, compared to the natural air-cooling method.Under the experimental conditions studied, the maximum temperature of the battery pack is found to be within the desired value during forced convection cooling only up to 1.5C discharge rate, while the immersion cooling performed satisfactorily up to 2C discharge rate. This study demonstrates direct liquid contact cooling with low-cost dielectric fluids as a safe and efficient thermal management technology for high-energy density and high-current lithium-ion battery applications.

Evaluation of precooling methods for shelf-life enhancement of pear (Pyrus spp.) fruits under ambient storage

Patharnakh pear fruits were freshly harvested at the physiological maturity during second week of July and subjected to different precooling treatments, viz. Hydrocooling (HC), Forced Air Cooling (FAC) and Evaporative Cooling (EC). The effect of these methods on fruit shelf-life and quality attributes under ambient conditions was investigated during the year 2021–22 at Punjab Horticultural Post harvest Technology Centre, Punjab Agricultural University, Ludhiana, Punjab. In all treatments, temperature of fruit pulp was regularly checked with digital pulp thermometer until a constant temperature was accomplished. Thereafter, the fruits were packed in corrugated fibre board boxes of 2 kg capacity and stored at ambient conditions (28–32°C and 70–80% relative humidity). The stored samples were assessed, periodically, at 5 days interval till 20 days for physiological and biochemical parameters. The results of the study revealed that FAC maintained lower physiological weight loss, spoilage and retained higher fruit firmness, sensory quality score, juice TSS, total sugars, acidity, vitamin C and total phenolic content during storage compared to the control. This method is an effective approach for maintaining the post-harvest shelf-life of perishable pear fruits for about 15 days in comparison to 10 days in the untreated control fruits.

Thermal Performance Improvement of Forced-Air Cooling System Combined with Liquid Spray for Densely Packed Batteries of Electric Vehicle

Thermal Performance Improvement of Forced-Air Cooling System Combined with Liquid Spray for Densely Packed Batteries of Electric Vehicle

Comparison of Three Cooling Methods (Hydrocooling, Forced-Air Cooling and Slush Icing) and Plastic Overwrap on Broccoli Quality during Simulated Commercial Handling

Broccoli is a highly perishable crop, due to its high respiration rate, and rapidly loses quality under inappropriate handling temperatures. The objective of this study was to evaluate the effect of commercial hydrocooling (HY), forced-air cooling (FA) or slushed-ice cooling (SI) on the quality and shelf-life of two commercial broccoli cultivars (‘Marathon’ and ‘Eastern Crown’) grown in northeast Florida during the early spring season. Following HY and FA, individual bunches (‘Marathon’) or crowns (‘Eastern Crown’) were placed in plastic film bags and stored at 1 °C for 7 days then transferred to 5 °C for 8 days to simulate retail conditions. It was found that HY removed the field heat 3.6 and 4.8 times faster than FA and SI, respectively. For both cultivars, using a texture analyzer, broccoli cooled by SI were softer (20.4 to 27.9 N) with higher head deformation than those by HY or FA (45.6 to 58.9 N) after 15 days of storage. Overall appearance of both cultivars decreased during storage if infected in the field by the fungal pathogen Alternaria brassicicola, which causes black spot disease. However, by the end of storage ‘Eastern Crown’ had a higher quality rating (6.2) than ‘Marathon’ (5.4). Broccoli floret moisture content was not affected during storage; however, ‘Marathon’ had higher moisture content (94.7%) than ‘Eastern Crown’ (89.2%). Yellowing was expressed more for ‘Marathon’, which had higher chroma* value (21.4) and lower hue* angle (h*) (122.3) value than ‘Eastern Crown’ after 7 days at 1 °C, plus 8 days at 5 °C. Carotenoid content was similar for both cultivars at harvest (2.3 mg/100 g) then decreased 39% for ‘Marathon’ and 12% for ‘Eastern Crown’ by day 15. Total chlorophyll was similar for both cultivars throughout storage (22.6 mg/100 g). Ascorbic acid decreased for both cultivars during storage but was higher in ‘Eastern Crown’ (92.0 to 101.9 mg/100 g) compared to ‘Marathon’ (80.7 to 88.6 mg/100 g). Hydrocooling and forced-air plus overwrapping have potential to reduce cooling costs during commercial handling.

Exploring novel carton footprints for improved refrigerated containers usage and a more efficient supply chain

Large quantities of fresh produce are exported every year to international markets across the world using refrigerated freight containers (RFCs). However, many packaging systems are legacy designs for older shipping technologies. For fruit, more than 10% of the RFC floor area is unused by current packaging systems, and designs often do not facilitate adequate cooling conditions. This study showed that novel packaging designs could improve packing density by up to 19%. Two new packaging systems were investigated using CFD to emulate conditions similar to forced-air cooling (FAC) and a RFC, respectively. The proposed packaging increased floor area utilisation to about 98%. The FAC energy efficiency was improved by 29%. An analysis of the results indicates considerable cooling improvements are possible by modifying vent hole designs and using taller cartons. The study thus demonstrated substantial merits to implementing new fruit packaging systems.

Experimental studies of liquid immersion cooling for 18650 lithium-ion battery under different discharging conditions

In this study, fluorinated liquid immersion cooling as a new cooling scheme has been tested and discussed for cooling the 18650 lithium-ion battery (LIB). SF33, with the boiling point of 33.4 °C, is chosen as the liquid for the immersion cooling. Comparison of the SF33 immersion cooling and forced air cooling (FAC) for the 18650 LIB under 2C, 4C and dynamic load conditions are made. It is found that the immersion cooling better cools the battery under all these conditions. Under 4C discharging, the maximum cell temperature rise is 14.06 °C for the FAC, while is 4.97 °C for the SF33 immersion cooling. As the temperature of SF33 basically governs the cell temperature, the SF33 temperature should not be too low. This study demonstrates that the LIB has non-negligible power losses under SF33 temperature of 10 °C and 15 °C, compared with the temperatures above 20 °C. Lastly, the two-phase boiling heat transfer mechanisms associated with immersion cooling are discussed with bubble dynamics analysis. It is found under a higher C rate, more aggressive boiling heat transfer is induced. The battery temperature is controlled to be below 34.5 °C even under 7C discharging condition.

Effect of in-process cooling on microstructure and mechanical properties of dissimilar AA2014 and AA7075 friction stir welded joints

Heat-carrying capacity of a cooling medium is critical as it governs microstructure evolution and tensile properties during friction stir welding (FSW). In this research, three cooling techniques: conventional air-cooling (CAC), forced air-cooling (FAC), and water flow cooling (WFC), were employed to study the effect on microstructure and mechanical properties in dissimilar FSW of AA2014 and AA7075. In-process cooling significantly influenced weld microstructure, zone size, microhardness, and tensile properties, which varied with the cooling medium. Water flow cooling was the most effective cooling technique due to its higher heat carrying capacity than CAC and FAC. Water flow cooling resulted in a drastically refined grains structure of smaller size in all zones, had higher tensile strength, elongation, and heat-affected (HAZ) hardness than CAC and FAC. Greatly refined grain structure and less dissolution of precipitates in weld nugget zone (WNZ) along with smaller HAZ and thermo-mechanically affected zone (TMAZ) are responsible for improved weld properties of WFC than the FAC and CAC. Forced air-cooling resulted in a higher microhardness value at WNZ, followed by WFC and CAC. Fractured surfaces of the tensile specimen were scrutinized by scanning electron microscope. Cooling did not affect the fracture side and location; however, fracture mode changed with cooling medium viz. ductile for FAC and WFC and mixed-mode for CAC.

Forced-air cooling of iceberg lettuces: Cooling efficiency in relation to commercial operating strategies

Commercial forced-air cooling (FAC) of iceberg lettuce is usually not ideal due to multiple uncontrollable factors in the pre-cooling facility, artificial non-standardized operations and operator experience used to select the pre-cooling time. This study aimed to investigate the cooling efficiency (cooling rate, heat load and energy consumption) during commercial FAC of iceberg lettuce under two kinds of operating mode. Our field studies demonstrated that when pallets were loaded in batches with a 20 min interval (Operation A) better cooling effectiveness and less energy consumption was achieved in comparison to when all pallets were loaded and pre-cooled simultaneously (Operation B). The seven-eighths cooling time (SECT) of pallets with the lowest cooling rate in the Operation A (227 min) and Operation B (325 min) were reduced by 43.2 % and 18.8 %, respectively, compared to worker experience estimated time (400 min). In addition, the heat load analysis results indicated that Operation A was an effective way to achieve the goal of enhancing the energy efficiency of the refrigeration unit and keeping the compressor operating under the design condition.

Multi-parameter analysis of air flow velocity on peach precooling efficiency using CFD

In the present work, a three-dimensional computational fluid dynamics (CFD) model was established to simulate the heat transfer process at different air-inflow velocities, and to predict the spatial and temporal variations of temperature distribution during forced-air cooling (FAC). Based on the conventional evaluation system, a more comprehensive multi-parameter evaluation system was proposed to determine an optimal precooling strategy of various air-inflow velocities. The current system employed a novel heterogeneity index to quantify the overall uniformity (OHI), and added a detailed theoretical calculation procedure of the cumulative moisture loss during the forced-convection cooling (M, mg). By analysing the effect of different airflow rates on SECT, precooling uniformity, moisture loss, and energy requirement, an airflow rate in the range of 1.5 - 2.5 m·s-1 was recommended as optimum for harvested peach precooling. Any further increase in air-inflow velocity led to excessive energy cost since it generated a relatively low decrease in SECT and overall heterogeneity index, so as moisture loss. At the same time, the moisture loss of peach primarily occurred in HCT, which was inversely proportional to airflow rate and cooling uniformity. An increasing power-law function relationship existed between energy consumption and airflow rate. The present work demonstrated the effect of various air-inflow velocities on peach precooling efficiency, and provided an integral evaluation system to optimise the precooling strategy of other horticultural fruits.

Structure Parameters Optimization of the Rain Cover and Ventilation Duct of Dry Air Core Reactor under the Forced Air Cooling Condition

In this paper, the three‐dimensional fluid field‐temperature field coupled model of air core reactor is established, the detailed temperature field distributions of reactor can be obtained, and the reason about the temperature rise of reactor is significant increased when adding the rain cover is given by analyzing the flow velocity of fluid in the air ducts. Considering the natural air cooling no longer meets the temperature rise requirement of the reactor, the forced air cooling is performed by installing ventilation duct and fan at the bottom of the reactor, combined with the finite element method and central composite experimental design method (CCD), the influence of structure parameters of rain cover and ventilation duct on the temperature rise of reactor are analyzed, meanwhile, the response surface model is established, which reflects the relationship between the temperature of reactor and the structure parameter of rain cover and ventilation duct, and the optimal design parameters can be obtained based on the quantum genetic algorithm, the maximum temperature of the reactor is only 59.3°C, the difference between the prediction of response surface and simulation result is only 0.1°C, and the correctness of the optimization method is validated, which provides an important guiding significance for the safe and stable operation of reactor in the system. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Modeling and Inconsistency Analysis of Parallel-connected Battery Module with Forced-air Cooling

Modeling and Inconsistency Analysis of Parallel-connected Battery Module with Forced-air Cooling

Influence of Interlayer Forced Air Cooling on Microstructure and Mechanical Properties of Wire Arc Additively Manufactured 304L Austenitic Stainless Steel

Wire‐and‐arc additive manufacturing (WAAM) is an innovative technology that involves deposition of subsequent layers of molten materials. Due to the high deposition rates, this technology is suitable for the production of large‐scale complex structures. Further enhancement in the productivity can be achieved by an interlayer cooling strategy that reduces idle time between depositions. However, the effect of the interlayer cooling on microstructure and mechanical properties has to be addressed. In this view, the present work compares microstructural features and mechanical properties of WAAM‐produced plates of austenitic AISI 304 L, focusing on the effect of both active interlayer air cooling and possible anisotropy induced by the additive process. Microstructural and mechanical characterization was conducted on samples extracted along the longitudinal, transverse, and diagonal directions to the deposition layers of WAAM plates, processed with and without interlayer active cooling. Results showed no remarkable influence of cooling conditions on the microstructure and mechanical properties of WAAM plates, which are indeed affected by the anisotropy induced by the additive process. The observed anisotropy in the elastic modulus, independent from different cooling conditions, was related to the crystallographic texture consequent to the highly oriented microstructure typically induced by the process.

Design and Optimization of Forced-Air Cooling System for Commercial Vehicle Brake System

Design and Optimization of Forced-Air Cooling System for Commercial Vehicle Brake System

Quality Change During MAP Storage of Strawberry (Fragaria × ananassa Duch.) After Forced-Air Cooling with Silicone Rubber Pads

Quality Change During MAP Storage of Strawberry (Fragaria × ananassa Duch.) After Forced-Air Cooling with Silicone Rubber Pads