An effective battery thermal management system (BTMS) is essential to ensure that the battery pack operates within the normal temperature range, especially for multi-cell batteries. This paper ...studied the optimal configuration of an air-cooling (AC) system for a cylindrical battery pack. The thermal parameters of the single battery were measured experimentally. The heat dissipation performance of a single battery was analyzed and compared with the simulation results. The experimental and simulation results were in good agreement, which proves the validity of the computational fluid dynamics (CFD) model. Various schemes with different battery arrangements, different positions of the inlet and outlet of the cooling system and the number of inlets and outlets were compared. The results showed that an arrangement that uses a small length-width ratio is more conducive to promoting the performance of the cooling system. The inlet and outlet configuration of the cooling system, which facilitates fluid flow over most of the battery pack over shorter distances is more beneficial to battery thermal management. The configuration of a large number of inlets and outlets can facilitate more flexible adjustment of the fluid flow state and can slow down battery heating to a greater extent.
Efficient fast-charging technology is necessary for the extension of the driving range of electric vehicles. However, lithium-ion cells generate immense heat at high-current charging rates. In order ...to address this problem, an efficient fast charging–cooling scheduling method is urgently needed. In this study, a liquid cooling-based thermal management system equipped with mini-channels was designed for the fast-charging process of a lithium-ion battery module. A neural network-based regression model was proposed based on 81 sets of experimental data, which consisted of three sub-models and considered three outputs: maximum temperature, temperature standard deviation, and energy consumption. Each sub-model had a desirable testing accuracy (99.353%, 97.332%, and 98.381%) after training. The regression model was employed to predict all three outputs among a full dataset, which combined different charging current rates (0.5C, 1C, 1.5C, 2C, and 2.5C (1C = 5 A)) at three different charging stages, and a range of coolant rates (0.0006, 0.0012, and 0.0018 kg·s−1). An optimal charging–cooling schedule was selected from the predicted dataset and was validated by the experiments. The results indicated that the battery module’s state of charge value increased by 0.5 after 15 min, with an energy consumption lower than 0.02 J. The maximum temperature and temperature standard deviation could be controlled within 33.35 and 0.8 °C, respectively. The approach described herein can be used by the electric vehicles industry in real fast-charging conditions. Moreover, optimal fast charging–cooling schedule can be predicted based on the experimental data obtained, that in turn, can significantly improve the efficiency of the charging process design as well as control energy consumption during cooling.
The application of lithium‐ion batteries especially for electric vehicles has been limited by the factors of safety, lifetime, charging time, and cost. One of the principal limitations is that the ...performance of Li‐ion batteries drops intensely in a cold environment. Cold environment dramatically reduces the available capacity of the batteries and increases its internal impedance at the same time. Therefore, the estimation of state‐of‐health is of great importance in battery performance evaluation and lifetime prediction. Furthermore, the heating methods need to be developed to ensure that batteries work in abnormal temperature conditions. This paper conducts a comprehensive review specifically on the poor performance of lithium‐ion cells under severe conditions. The content contains three sections. First, a comprehensive study on the aging mechanisms of lithium‐ion batteries at cold temperatures is undertaken. Second, the estimation methods of the health state of the batteries are conducted, which is vital to understand the fundamentals and quantify the performance and aging effects for lithium‐ion batteries. Third, the heating methods are classified and studied in detail to reduce the degradation mechanism and promote the performance of lithium‐ion batteries under sub‐zero conditions.
This paper conducts a comprehensive study of the aging mechanisms at cold temperatures. Estimation methods of the state of health for the batteries are conducted. The heating methods (internal) are classified and studied in detail.
An energy-storage system comprised of lithium-ion battery modules is considered to be a core component of new energy vehicles, as it provides the main power source for the transmission system. ...However, manufacturing defects in battery modules lead to variations in performance among the cells used in series or parallel configuration. This variation results in incomplete charge and discharge of batteries and non-uniform temperature distribution, which further lead to reduction of cycle life and battery capacity over time. To solve this problem, this work uses experimental and numerical methods to conduct a comprehensive investigation on the clustering of battery cells with similar performance in order to produce a battery module with improved electrochemical performance. Experiments were first performed by dismantling battery modules for the measurement of performance parameters. The k-means clustering and support vector clustering (SVC) algorithms were then employed to produce battery modules composed of 12 cells each. Experimental verification of the results obtained from the clustering analysis was performed by measuring the temperature rise in the cells over a certain period, while air cooling was provided. It was found that the SVC-clustered battery module in Category 3 exhibited the best performance, with a maximum observed temperature of 32 °C. By contrast, the maximum observed temperatures of the other battery modules were higher, at 40 °C for Category 1 (manufacturer), 36 °C for Category 2 (manufacturer), and 35 °C for Category 4 (k-means-clustered battery module).
As a rotational speed controller, a hydro-viscous clutch (HVC) is usually used in the constant pressure water supply system to maintain the needed water pressure constant. However, when the ...hydro-viscous clutch is working, it often suffers from the problem of output rotational speed fluctuation since the spool of proportional relief valve can easily get stuck. Consequently, water pressure will fluctuate too. A special pump control system of HVC was proposed based on the Fuzzy-PID controller for the purpose of reducing the fluctuation rate. The MATLAB simulation was carried out according to the mathematical model and the results show that the Fuzzy-PID control strategy is superior to traditional PID control. The corresponding experiment was performed and the result indicate that through applying the Fuzzy-PID controller based pump control system, the rotational output speed fluctuation of HVC can be inhibited from ±60π to ±6π rad/min, and the water pressure fluctuation is dropped from ±0.1 to ±0.002 MPa.
The thrust system of a tunnel boring machine plays a crucial role by driving the machine ahead and supporting the gripper shoes stably. A thrust hydraulic control system, assembled with a ...proportional flow control valve and a pressure relief valve, is established with system operating parameters. The mathematical model of a thrust electrohydraulic system is presented. To improve the control characteristics of the thrust system, a self-tuning fuzzy PID controller was introduced in synchronization motion control situations. To attain the best control parameters, three synchronization motion control systems were used to control the thrust propel cylinders. Tests on a Ø2.5 m scaled TBM test rig were carried out to verify the capabilities of the ISCS, SRSCS and CRSCS. Comparative tests were conducted, and the results showed that the thrust system adopting SRSCS achieved the least oscillation and the quickest response. The steady-state displacement error decreased by about 33.3% in contrast to the ISCS and CRSCS.
•Experimental study for ultrasonic welding process of polymer blends is undertaken.•Data comprising of two measured outputs (weld strength, heat generation) is obtained.•Artificial neural network is ...applied to build the predictive models for each output.•2-D and 3-D plots of models give detailed insights into welding parameters.•Optimization of models using NSGA II results in maximum value of weld strength.
This paper presents a study undertaken with an objective to establish ultrasonic welding process for joining polymer blends expressed to aid the eco-friendly qualities desired in manufacturing sectors. Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) blends are welded after creating suitable parts with energy directors using injection molding techniques. It is imperative to estimate the performance of the weld preferred in industrial sectors to be expressed in terms of strength along with the maximum heat generated. Experiments are conducted by varying three of the process parameters namely amplitude, pressure and weld time with measurement of responses such as the tensile strength and heat generated. Artificial neural network (ANN) algorithm is then used to formulate models for each of the measured response. NSGA II is then applied for optimization of models for achieving higher weld strength created with an optimal level of heating. The weld strength of 6.02 N mm−2 is achieved with the welding parameters of amplitude (33.14 µm), pressure (4.03 bar) and weld time (3.35 s). The heat generated at the weld (146.20 °C) is achieved with the welding parameters of amplitude (40.89 µm), pressure (4.29 bar) and weld time (4.52 s).
•Battery heat generation model is analysed with experiments to get thermal parameters.•Temperature standard deviation is analysed in thermodynamics for heat uniformity.•Maximum pressure, which ...affects running cost, is considered in fluid dynamics.
Thermal management of lithium-ion battery modules is essential to avoid thermal issues such as overheating and thermal runaway. Liquid-cooling is an efficient cooling method, and many publications can be found in this area. However, a parametric study on the influence of structural parameters on the cooling effect is still lacking. This article proposes a comprehensive way to quantitively evaluate the cooling effect of a liquid-cooled battery module. Computational fluid dynamics is used to establish the fluid-solid coupled heat dissipation model, using the thermal parameters values from experiments. Parameter combination samples are generated using the Latin Hypercubes method, and the effect of structural parameters on heat dissipation performance is determined using sensitivity analysis. Multi-Objective optimization is then performed to develop a cooling system with lower temperature and lower energy consumption. The optimized design is then verified by heat-dissipation experiments of a battery module set-up. The proposed method can be easily implemented in industrial battery pack manufacturing. The results show that with the same input power, the temperature reduction will be higher, 1.87 °C; and the temperature deviation can also be controlled within a small range, 0.35 °C.
•Surrogate thermal models and optimization to improve air cooling performance.•Optimized battery pack behaves better cooling effect and occupies less space.•Easily applied methodology for industrial ...battery pack with hundreds of cells.
The battery packs in electric vehicles usually operate at high current discharge rates which leads to the higher heat generation. This may have safety issues and negative impact on the battery performance over the period. Existing researches focused more on the configurations and design of battery cells/modules arrangements to reduce the maximum temperature rise of the battery pack. However, temperature differences are more important and difficult to manage. It is also known that smaller the size of the battery pack, higher the space can be saved. This article proposes a comprehensive methodology to design an efficient air-cooling system, which is hybrid of system volume and cooling performance. The proposed methodology comprises of the four steps: the design of air cooling battery, setup of the computational fluid dynamics codes, design of experiments (DoE), evaluation and selection of surrogate models. These models are then optimized using the multi-objective optimization approach for the selection of optimum scheme for air cooling battery module. The optimization results show that the optimized air cooling battery module has higher thermal performance. The proposed methodology will be useful for industrial battery pack design process to reduce maximum temperature, temperature difference and the volume of battery pack.
•Heat dissipation model considering the inconsistent thermal property of batteries is established.•Inlet and outlet in the same side of the battery pack guarantees better thermal performance than a ...both-side placement.•Maximum temperature is more dependent on inlet vent height than on outlet vent height.•Uneven gap design contributes to better thermal performance than even gap design.
A lithium-ion battery pack is the power source of an electric vehicle, and its temperature rise is one of the main concerns. Existing research mainly focused on the design of cooling systems, and always used computational fluid dynamics to analyze the thermal behavior of batteries, regardless of the individual differences of batteries. In this paper, the heat dissipation performance of air-cooled battery packs considering the different thermal performance of different batteries was studied. A more realistic thermal model of the battery pack at 1C discharge rate was obtained through equivalent calculation and experimental verification. The results showed that the temperature of batteries with different thermal performance rose faster and the temperature difference was larger. At the same time, the thermal performance of the battery can be improved by placing the outlet and inlet on the same side. The thermal performance was more sensitive to the inlet exhaust height than to the outlet exhaust height. The research results can provide a basis for exploring the design method of battery packs with better heat dissipation performance, lower energy consumption, and a smaller volume.
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