Design and Optimization of a Liquid Cooling Thermal Management System with Flow Distributors and Spiral Channel Cooling Plates for Lithium-Ion Batteries
Abstract and Figures
In this study, a three-dimensional transient simulation model of a liquid cooling thermal management system with flow distributors and spiral channel cooling plates for pouch lithium-ion batteries has been developed. The cooling plates play the role of uniforming temperature distribution and reducing the maximum temperature within each battery, while the flow distributors have the function of reducing the temperature difference between batteries in the battery module. The accuracy of the thermophysical properties and heat generation rate of the battery was verified experimentally. The optimal structure and cooling strategy of the system was determined by single factor analysis as well as orthogonal test and matrix analysis methods. The optimal solution resulted in a maximum battery module temperature of 34.65 °C, a maximum temperature difference of 3.95 °C, and a channel pressure drop of 8.82 Pa. Using the world-harmonized light-duty vehicles test cycle (WLTC) conditions for a battery pack in an electric car, the performance of the optimal battery thermal management system (BTMS) design was tested, and the results indicate that the maximum temperature can be controlled below 25.51 °C and the maximum temperature difference below 0.21 °C, which well meet the requirements of BTMS designs.
Figures - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
... The usage of a liquid cooling thermal management system with a dichotomous flow distributor and a liquid cooling plate with a spiral channel (Figure 7) suitable for highrate discharge circumstances was suggested in this study on pouch lithium-ion batteries conducted by Li et al. [51]. Orthogonal testing and matrix analysis procedures were used to optimize the liquid cooling plate's structural design. ...
... (a) Liquid cooling system of a battery module; (b) coolant flow path; (c) flow distributor structure; and (d) structure of the liquid cooling plates.[51] ...
Electric vehicles (EVs) have become a viable solution to the emerging global climate crisis. Rechargeable battery packs are the basic unit of the energy storage system of these vehicles. The battery thermal management system (BTMS) is the primary control unit of the energy source of the vehicles. EV performance is governed by specific power, charging/discharging rate, specific energy, and cycle life of the battery packs. Nevertheless, these parameters are affected by temperature, making thermal management the most significant factor for the performance of a battery pack in an EV. Although the BTMS has acquired plenty of attention, research on the efficiency of the liquid cooling-based BTMS for actual drive cycles has been minimal. Liquid cooling, with appropriate configuration, can provide up to 3500 times more efficient cooling than air cooling. Direct/immersive and indirect liquid cooling are the main types of liquid cooling systems. Immersive/direct cooling utilizes the technique of direct contact between coolant and battery surface, which could provide larger heat transfer across the pack; however, parameters such as leakage, configuration, efficiency, etc., are needed to be considered. Indirect cooling techniques include cold plates, liquid jackets, discrete tubes, etc. It could result in complex configuration or thermal non-uniformity inside the pack. The paper intends to contribute to the alleviation of these gaps by studying various techniques, including different configurations, coolant flow, nanoparticles, varying discharging rates, different coolants, etc. This paper provides a comprehensive perspective of various techniques employed in liquid cooling battery packs, identifying the shortcomings in direct/immersive and indirect liquid cooling systems and discussing their mitigation strategies.
... The role of the battery thermal management system (BTMS) is to regulate the temperature of the battery within suitable ranges during all operating conditions, including cooling and heating insulation, to maintain its optimal performance and state of charge. Depending on the cooling medium, the thermal management of the battery system can be classified into several forms, including air-cooling systems [21][22][23][24], liquid-cooling systems [25][26][27][28], phase-change material systems [29][30][31][32][33], heat-pipe cooling systems [34][35][36][37][38], and hybrid cooling systems [39][40][41][42][43]. ...
Given the growing demand for increased energy capacity and power density in battery systems, ensuring thermal safety in lithium-ion batteries has become a significant challenge for the coming decade. Effective thermal management plays a crucial role in battery design optimization. Air-cooling temperatures in vehicles often vary from ambient due to internal ventilation, with external air potentially overheating due to vehicle malfunctions. This article highlights the efficiency of lateral side air cooling in battery packs, suggesting a need for further exploration beyond traditional front side methods. In this study, we examine the impact of three different temperature levels and two distinct air-cooling directions on the performance of an air-cooling system. Our results reveal that the air-cooling direction has a more pronounced influence compared with the air-cooling temperature. By employing an optimal air-cooling direction and ambient air-cooling temperature, it is possible to achieve a temperature reduction of approximately 5 K in the battery, which otherwise requires a 10 K decrease in the air-cooling temperature to achieve a similar effect. Therefore, we propose an empirical formula for air-cooling efficiency under various conditions, aiming to provide valuable insights into the factors affecting air-cooling systems for industrial applications toward enhancing the fire safety of battery energy storage systems.
... The parallel flow channel cooling method showed a more uniform temperature distribution, with an optimized layout of parallel channels maintaining the maximum battery temperature below 36 • C while keeping the maximum temperature difference within 4.17 • C at a 3C discharge rate. The U-shaped lightweight liquid cooling method developed by Li et al. [21] improves the thermal safety and weight optimization of prismatic battery cells. It led to a 21% decrease in maximum battery temperature and a 45% reduction in cooling plate weight, showing promise for electric vehicle use. ...
The battery thermal management system (BTMS) for lithium-ion batteries can provide proper operation conditions by implementing metal cold plates containing channels on both sides of the battery cell, making it a more effective cooling system. The efficient design of channels can improve thermal performance without any excessive energy consumption. In addition, utilizing phase change material (PCM) as a passive cooling system enhances BTMS performance, which led to a hybrid cooling system. In this study, a novel design of a microchannel distribution path where each microchannel branched into two channels 40 mm before the outlet port to increase thermal contact between the battery cell and microchannels is proposed. In addition, a hybrid cooling system integrated with PCM in the critical zone of the battery cell is designed. Numerical investigation was performed under a 5C discharge rate, three environmental conditions, and a specific range of inlet velocity (0.1 m/s to 1 m/s). Results revealed that a branched microchannel can effectively improve thermal contact between the battery cell and microchannel in a hot area of the battery cell around the outlet port of channels. The designed cooling system reduces the maximum temperature of the battery cell by 2.43 °C, while temperature difference reduces by 5.22 °C compared to the straight microchannel. Furthermore, adding PCM led to more uniform temperature distribution inside battery cell without extra energy consumption.
This paper introduced for the first time a viscoelastic hybrid nanofluid as the coolant for direct contact cooling power battery. The governing boundary layer equations were established by adopting fractional Oldroyd-B model and fractional Buongiorno’s model. Second-order velocity slip boundary conditions were also considered. Then the solutions were numerically acquired by finite difference coupled with L1 algorithm. Impact of main physical parameters on the flow, heat and mass transfer of the viscoelastic hybrid nanofluid on the cylindrical battery was graphically presented and detailly discussed. Outcomes show that the heat transfer is improved by both Brownian motion(Nb) and thermophoresis(Nt) to different degrees. When Nb grows from 0.05 to 0.1, the average Nusselt number increases by 2.2%, higher than 0.027% of Nt. The slip behavior only affects the velocity distribution near the individual cell and slightly enhances heat and mass transfer. The velocity relaxation fractional derivative contributes to convection, heat and mass transfer on the cell wall, while velocity retardation fractional derivative behaves just the opposite. The proposed viscoelastic hybrid nanofluid with appropriate volume fractions of nanoparticles enhances heat transfer on the cell wall and is strongly recommended as a candidate for power battery coolant.
To ensure optimum working conditions for lithium-ion batteries, a numerical study is carried out for three-dimensional temperature distribution of a battery liquid cooling system in this work. The effect of channel size and inlet boundary conditions are evaluated on the temperature field of the battery modules. Based on the thermal behavior of discharging battery obtained experimental measurements, two temperature control strategies are proposed and studied. The results show that the channel width of the cooling plates has a great influence on the maximum temperature in the battery module. It is also revealed that increasing inlet water flow rate can significantly improve the heat transfer capacity of the battery thermal management system, while the relationship between them is not proportional. Lowering the inlet temperature can reduce the maximum temperature predicted in the battery module significantly. However, this will also lead to additional energy consumed by the cooling system. It is also found that the Scheme 5 among various temperature control strategies can ensure the battery pack working in the best temperature range in different depths of discharge. Compared with the traditional one with a given flow rate, the parasitic energy consumption in Scheme 5 can be reduced by around 80%.
Excellent thermal management is very significant in preserving lithium-ion battery cell work-performance and extending cell cycle-life. This work presents a method of thermal control for a large-scale pouch cell by using an existing liquid cooling plate with streamline channels. Numerically, influences of mass flow rates, cooling trigger-time, and glycol solution concentration on the cell thermal distribution are analyzed in detail. Experimentally, the simulation effectiveness is validated by a constructed thermal test system. It is shown that the increasing mass flow rate plays a positive role in crippling the cell temperature rise and difference. However, there is a marginal effect in this condition. Effect of postponing cooling trigger-time on promoting the cell thermal homogeneity is negative, when the cooling starts at 31 °C, the final cell temperature and temperature difference beyond 32 °C and 5 °C, respectively. The maximum cell temperature and channel pressure drop increase with increasing glycol solution concentration from 0 to 80%. Experimental validation suggests that the test and simulation results coincide with each other (within 2.5 °C), indicating that a promising availability dwells in present thermal management to manage the cell temperature field under a desirable range. This study would be valuable for one to develop a reliable cooling solution for a battery pack stacked with large-scale pouch cells.
Accurate characterization of the heat generation rate (HGR) of lithium-ion batteries is critical for driving towards a cost-effective and efficient design of a thermal management system for various applications. Because of the increases in battery cell dimensions, as well as more aggressive operating conditions, heat generation seen at the cell level is becoming increasingly unevenly distributed. Proper design of the heat management system requires measurement of heat generation distribution at the cell level as a function of operating conditions, such as charging and discharging profiles, states-of-charge (SOC), temperature, and state-of-health (SOH). Currently, few commercial calorimeters are available for measurement of heat generation distributions under dynamic and varying operating conditions at reasonable price. In this paper, a new calorimeter is developed that allows for measurement of HGR in two-dimensions for a pouch format lithium-ion battery cell in real time, which consists of two thermoelectric assemblies (TEAs) with heat flux sensors to measure the HGR and temperature sensors to regulate the temperature. Distributed HGR of a large format pouch cell for automotive applications are measured as a function of different charging and discharging rates and SOCs as well as the variation of heat generation distribution during cell aging.
Liquid cooling is an effective thermal management technique in reducing the peak temperature of lithium-ion batteries. To meet the development of the battery thermal management system's compact design, a liquid-based mini channel cold plate is utilised. Although several researchers proposed numerous designs of mini channels across the cold plate, a comparative assessment among these designs is limited. Therefore, a three-dimensional numerical method is introduced to explore the laminar flow of liquid coolant in six distinct mini channel designs. This includes serpentine, U-bend, straight, pumpkin, spiral, and hexagonal designs under a constant channel volume. Their cooling ability is evaluated in terms of pressure drop, temperature variation, a non-dimensional j/f factor, average temperature, uniformity factor, and cooling performance factor for varying mass flow rate and a fixed discharge rate of 3C. Results signify that the serpentine and hexagonal geometries could significantly improve temperature homogeneity, whereas the pumpkin model maintains a lower pressure drop and pumping power. Furthermore, a detailed analysis is conducted with all the channel designs for an ambient temperature and discharge rate varying from 25 °C to 45 °C and 1C to 5C, respectively. Also, a realistic drive cycle data US06 is utilised to assess the performance of optimal design serpentine channel-based battery module for on-road driving conditions.
To improve the temperature uniformity and cooling performance of the battery module, a hybrid battery thermal management system (BTMS) with liquid cooling and phase change materials (PCM) containing different expanded graphite contents is proposed. To adjust the heat transfer efficiency of composite phase change material (CPCM) along the direction of liquid flow, the segments of CPCM matrix contain different expanded graphite (EG) contents. Subsequently, the effects of the layout of CPCM matrix, length distribution of each segment, the structure parameters and cooling strategy on cooling performance of the battery module are investigated using computational fluid dynamics (CFD) model at 4 C discharge rate and ambient temperature of 308.15K. The results demonstrate that the maximum temperature (Tmax) and temperature difference (ΔT) of BTMS adopting segmented layout III are significantly reduced by 1.3K and 1.4K respectively compared with layout Ⅰ. Additionally, the layout III exhibits optimal cooling performance when length of each segment is 110 mm, 120 mm and 120 mm, respectively. Moreover, the Tmax and ΔT decrease with increase of cell-to-cell spacing (L) and diameter of liquid channel (d), and ΔT is only 2.2K under the condition of L24d5 (L=24mm, d=5mm). During the 1 C-charging and 4 C-discharging cycles, the Tmax of BTMS with normal strategy remains at 319.5K and ΔT lower than 3K; furthermore the strategy of delayed liquid cooling can significantly reduce power consumption by 33.3% without sacrificing the cooling performance.
The parasitic power consumption of the battery thermal management systems is a crucial factor that affects the specific energy of the battery pack. In this paper, a comparative analysis is conducted between air type and liquid type thermal management systems for a high-energy lithium-ion battery module. The parasitic power consumption and cooling performance of both thermal management systems are studied using computational fluid dynamics (CFD) simulations. The 48V module investigated in this study is comprised of 12 prismatic-shape NMC batteries. An experimental test bench is built up to test the module without any cooling system under the natural convection at room temperature, and the numerical model of the module is validated with experimental results. Two different cooling systems for the module are then designed and investigated including a U-type parallel air cooling and a new indirect liquid cooling with a U-shape cooling plate. The influence of coolant flow rate and coolant temperature on the thermal behavior of the module is investigated for a 2C discharge process. It was found that for a certain amount of power consumption, the liquid type BTMS results in a lower module temperature and better temperature uniformity. As an example, for the power consumption of around 0.5 W, the average temperature of the hottest battery cell in the liquid-cooled module is around 3 °C lower than the air-cooled module. The results of this research represent a further step towards the development of energy-efficient battery thermal management systems.
Battery thermal management systems (BTMSs) ensure that battery packs working in a suitable environment to guarantee the safety and stability of the battery packs. In this study, a new type of liquid cooling BTMS based on the vertical layout of the tube (VLT) and a combination of the gradient increment tube diameter and gradient ratio flow velocity of the fluid medium is proposed. The discrete model based on the battery equivalent circuit model are established to analyze the thermal performance of battery module involving 25 cells in an aluminium frame with straight tubes. The effects of two kinds of tube layouts, fluid velocity, tube diameter, gradient ratio flow velocity and gradient increment tube diameter on the thermal performance of the battery module are discussed. The results show that in a certain range of flow velocity, the battery module with the vertical layout of the tube has better performance than the horizontal layout. In addition, compared with the constant flow velocity and constant tube diameter, the strategy of the gradient ratio flow velocity or gradient increment tube diameter can reduce the battery temperature difference, and the combination of the two can further improve the temperature uniformity. Furthermore, the results show that when the ambient temperature is -10 ∘C and 60 ∘C, the temperature difference of the battery module is reduced by 52.16% and 50.11%, respectively.
Liquid cooling system was critical to keep the performance of lithium-ion battery due to its good conductivity to keep battery working in a cool environment. In this study, a novel double helix cooling structure was designed for an 18650 lithium battery. The numerical simulation was carried out to investigate the effects of the coolant mass flow rate (M), helix groove pitch (P) and flow diameter (D) on cooling performance. The design points obtained by Latin hypercube sampling were calculated numerically. Kriging approximate model method was adopted to reduce computing time. Using Non-dominated Sorting Genetic Algorithm II obtained the Pareto solution, and the multiple criteria decision making (MCDM) algorithm was used to sort the optimal solution set. The results showed that increasing mass flow rate can effectively lower the maximum temperature and temperature difference of the battery within a certain range of mass flow rate. When the mass flow rate increased to a certain value, the benefit from increasing the mass flow was limited. And the pitch and diameter would also have a tendency to the decrease of the maximum temperature or even the opposite result when they exceeded a certain value. The best cooling performance can be obtained when the mass flow rate is 1.94×10⁻³ kg/s, the pitch is 100 mm and the diameter is 0.4 mm. The novel cooling structure proposed in this study can provided a new approach for the structure design of the liquid-cooled cylindrical battery thermal management system.
Entropy coefficient and internal resistance of lithium-ion batteries are the key thermal properties needed for an optimal design of thermal management systems. Currently, these two parameters are measured separately with either potentiometric or calorimetric method and EIS or HPPC method, respectively, which requires different equipment and experimental time due to the time needed to reach an equilibrium at a given SOC (state of charge). In addition, both results are discrete at given SOC points, which does not provide the values in-betweens. In this paper, we proposed a fast and highly efficient calorimetric method based on an isothermal calorimeter that allows for simultaneous and continuous characterization of these two parameters. The method is based on the wavelet analysis technique, where a sinusoidal AC with a small DC offset is used as an input for battery and the heat generation rate is measured as an output using the calorimeter. Then, the two parameters are determined simultaneously in time-frequency domain. The results are compared with those measured by the potentiometric method and EIS analysis, respectively with respect to measurement time and accuracy. The saved time is 95%, and the proposed method maintains the accuracy. In addition, the obtained parameters are used to calculate the total heat generation, which shows a good agreement with the experimental measured one both in the shape and tendency.
Fundamental understanding of heat generation of lithium-ion batteries during operations is crucial to the cost-effective and efficient design of a thermal management system in electric vehicles. Accurate characterization of the heat requires a calorimeter that meets inherent dynamics of the heat with accuracy. Therefore, we have developed an isothermal calorimeter using the thermoelectric assemblies (TEAs) along with the temperature control and Kalman filter, which is used to measure the heat generation rate (HGR) of large format pouch type lithium-ion batteries as an example. The measured HGR is a function of charge and discharge rates, state-of-charge (SOC), and temperatures. Analysis has shown that both the HGR and the ratio of the total heat generation to the total energy stored or released (pheat) of the tested cells increase as the current increases or the temperature decreases. In addition, a new calorimetric method is developed which enables a simultaneous determination of the entropy coefficient and internal resistance in the reversible and irreversible heat source terms in the frequency domain. The method can reduce the testing time about 92% compared with those by the conventional potentiometric method and EIS analysis, respectively, and the determined parameters are in good accordance with the reference values. Moreover, the calculated reversible and irreversible heat sources terms are compared with the experimental measurement and matched each other.