Liquid Cooling System Research Articles

Simulation and Experimental Study on Heat Transfer Performance of Bionic Structure-Based Battery Liquid Cooling Plate

This study presents a bionic structure-based liquid cooling plate designed to address the heat generation characteristics of prismatic lithium-ion batteries. The size of the lithium-ion battery is 148 mm × 26 mm × 97 mm, the positive pole size is 20 mm × 20 mm × 3 mm, and the negative pole size is 22 mm × 20 mm × 3 mm. Experimental testing of the Li-ion battery’s heat generation model parameters, in conjunction with bionic structure and micro-channel features, has led to the development of this innovative cooling system. The traditional bionic liquid cooling plate’s structure is often singular; however, the flow path of the liquid cooling plate designed in this paper is based on the combination of the distribution of human blood vessel branches and the structure of insect wing veins. The external dimension of the liquid cooling plate is 152 mm × 100 mm × 6 mm (length × width × height). Utilizing numerical simulation and thermodynamic principles, we analyzed the heat transfer efficacy of the bionic liquid cooling module for power batteries. Specifically, we investigated the impact of varying coolant flow rates and the contact radius between flow channels on the thermal performance of the bionic battery modules. Our findings indicate that a liquid flow rate of 0.6 m/s achieves a stable maximum surface temperature and temperature differential across the bionic battery liquid cooling module, with a relatively low overall system power consumption, suggesting room for further enhancement of heat transfer performance. By augmenting the contact radius between flow channels, we observed an initial increase in the maximum surface temperature, temperature differential, and inlet–outlet pressure differential at a flow rate of 0.2 m/s. However, at flow rates equal to or exceeding 0.4 m/s, these parameters stabilized across different design Scenarios. Notably, the pump power consumption remained consistent across various scenarios and flow rates. This study’s outcomes offer valuable insights for the development of liquid-cooled battery thermal management systems that are energy-efficient and offer superior heat transfer capabilities.

Experimental study on the thermal management performance of immersion cooling for 18650 lithium-ion battery module

Direct liquid cooling technology stabilizes the battery module at the ideal operating temperature by leveraging the coolant's high heat capacity and its heat dissipation ability through circulation. This study introduced a forced-flow immersion cooling method employing transformer oil as the cooling medium for 18650 lithium-ion battery modules. The performance of this cooling system design was assessed under various discharge rates, coolant flow rates, and channel positions. Experimental data reveals that the average temperature of the oil-immersion-cooled battery module was around 26.3% lower than that of the naturally air-cooled battery module under a 2C discharge condition with zero flow rate. The cooling capacity of the oil-immersion system was limited, with theoretical analyses indicating an optimal flow rate of 200mL/min. Four unique cooling channel configurations was designed: side center inlet to center outlet, side upper inlet to lower outlet, front upper inlet to lower outlet, and front center inlet to center outlet. The peak temperatures of the battery module for these setups were 31.7 ℃, 31.0 ℃, 31.0 ℃, 31.0 ℃, and 31.6 ℃, respectively, with a temperature difference of about 2 ℃. Notably, the side upper inlet to lower outlet channel configuration displays superior cooling performance. These findings contribute to advancing more efficient cooling systems and offer valuable insights for optimizing direct liquid-cooled thermal management systems for lithium-ion batteries in the future.

Simulation of hybrid air-cooled and liquid-cooled systems for optimal lithium-ion battery performance and condensation prevention in high-humidity environments

As demand for higher discharge rates surges, the trend towards colder liquid cooling in high-humidity environments poses condensation risks in lithium-ion battery thermal management systems, potentially leading to electrical safety hazards. This study introduces an innovative hybrid air-cooled and liquid-cooled system designed to mitigate condensation in lithium-ion battery thermal management systems (BTMS) operating in high-humidity environments. The proposed system features a unique return air structure that enhances the thermal stability and safety of the batteries by recirculating air through the battery box, thereby utilizing residual heat to prevent condensation. Computational Fluid Dynamics (CFD) simulations were employed to analyze and optimize the system’s thermal management performance under various airflow velocities and temperature conditions. The study results show that compared to traditional liquid cooling systems, the proposed hybrid system reduces the condensation area by approximately 39.68 % at a wind speed of 0.5 m/s, and the temperature difference decreases by 0.35 K. The integration of flow deflectors further improves the anti-condensation effect, achieving a phase change rate greater than 0 in the cooling area, thereby enabling condensation-free operation throughout the entire cooling zone. A comprehensive evaluation using the entropy weight-TOPSIS method and nonlinear surface fitting was conducted to assess multiple schemes regarding heat dissipation, anti-condensation measures, and energy consumption. The optimal operating conditions were identified as an airflow velocity of 1.29 m/s and a liquid flow velocity of 0.22 m/s, resulting in a maximum temperature difference of 3.98 K, a maximum temperature of 302.36 K, and energy consumption of air cooling and liquid cooling is 0.158 J and 0.192 J. The proposed composite cooling system with a recirculation structure not only addresses the thermal management challenges of lithium-ion batteries but also effectively ensures the insulation safety of electronic components in high-humidity environments.

Comparative Study on Heat Dissipation Performance of Pure Immersion and Immersion Jet Liquid Cooling System for Single Server

Heat dissipation has emerged as a critical challenge in server cooling due to the escalating number of servers within data centers. The potential of immersion jet technology to be applied in large-scale data center server operations remains unexplored. This paper introduces an innovative immersion jet liquid cooling system. The primary objective is to investigate the synergistic integration of immersion liquid cooling and jet cooling to enhance the heat dissipation capacity of server liquid cooling systems. By constructing a single-server liquid cooling test bench, this study compares the heat dissipation efficiencies of pure immersion and immersion jet liquid cooling systems and examines the impact of inlet water temperature, jet distance, and inlet water flow rate on system performance. The experimental outcomes show that the steady-state surface heat transfer coefficient of the immersion jet liquid cooling system is 2.6 times that of the pure immersion system, with increases of approximately 475.9 W/(m2·K) and 1745.0 W/(m2·K) upon adjustment of the jet distance and flow rate, respectively. Furthermore, the system model is streamlined through dimensional analysis, yielding a dimensionless relationship that encompasses parameters such as inlet water temperature, jet distance, and inlet water velocity. The correlation error is maintained below 18%, thereby enhancing the comprehension of the immersion jet cooling mechanism.

Optimization Control Strategies and Evaluation Metrics of Cooling Systems in Data Centers: A Review

In the age of digitalization and big data, cooling systems in data centers are vital for maintaining equipment efficiency and environmental sustainability. Although many studies have focused on the classification and optimization of data center cooling systems, systematic reviews using bibliometric methods are relatively scarce. This review uses bibliometric analysis to explore the classifications, control optimizations, and energy metrics of data center cooling systems, aiming to address research gaps. Using CiteSpace and databases like Scopus, Web of Science, and IEEE, this study maps the field’s historical development and current trends. The findings indicate that, firstly, the classification of cooling systems, optimization strategies, and energy efficiency metrics are the current focal points. Secondly, this review assesses the applicability of air-cooled and liquid-cooled systems in different operational environments, providing practical guidance for selection. Then, for air cooling systems, the review demonstrates that optimizing the design of static pressure chamber baffles has significantly improved airflow uniformity. Finally, the article advocates for expanding the use of artificial intelligence and machine learning to automate data collection and energy efficiency analysis, it also calls for the global standardization of energy efficiency metrics. This study offers new perspectives on the design, operational optimization, and performance evaluation of data center cooling systems.

Optimization design of liquid-cooled battery thermal management system based on wavy tube

Optimization design of liquid-cooled battery thermal management system based on wavy tube

Liquid Hydrogen Cooling System for 100 kW-Class HTS Rotor Thermal Design

Liquid Hydrogen Cooling System for 100 kW-Class HTS Rotor Thermal Design

Two novel dual-tube photovoltaic-thermal collector designs with improved performance for liquid-cooled photovoltaic-thermal systems

Photovoltaic-thermal (PVT) collectors developed over the years have achieved reduced photovoltaic (PV) panel temperature and improved electrical efficiency mostly based on single-tube spiral and serpentine configurations of the cooling pipes. However, the design and analysis of PVT collector configurations incorporating multiple serpentine tubes, capable of simultaneously reducing both the average PV panel temperature and temperature non-uniformity within the panel, are rare. The present work introduces two novel designs PVT collector systems by incorporating dual-tube arrangements, namely, the Dual-Tube Uni-Directional (DTUD) and the Dual-Tube Opposite-Directional (DTOD) systems. The new collectors' performance is numerically analysed through three-dimensional (3D) simulations. The highest net powers are obtained with 32 cooling loops in both the DTUD and DTOD designs for the given flow rate and panel area. The DTUD-based PVT system yields up to 10.39 % and 10.36 % gains in electrical efficiency and net power, respectively. On the contrary, the DTOD system also results in gains of these parameters, albeit marginally less than the DTUD arrangement. However, the DTOD arrangement results in reduced maximum PV panel temperature, which can positively impact the panel's life span.

A topology optimization-based-novel design and comprehensive thermal analysis of a cylindrical battery liquid cooling plate

In previous studies, the designs of the liquid cooling channel for battery packs usually paid emphasis on optimizing the predefined cooling channels. This significantly restricts the possibilities for geometric modifications of cooling channels, consequently placing limitations on the potential improvement in heat dissipation performance. To address these limitations, this study proposes a Topology optimization-based-novel design and comprehensive thermal analysis of a cylindrical battery liquid cooling plate. The aim of using topology optimization is to overcome these constraints, enabling more flexible and global domain designs. Three different inlet–outlet configurations of the cooling plate structure were designed using a dual-objective optimization function. A comprehensive numerical analysis was conducted and the topology-optimized liquid cooling plate system was compared with two other cooling pipe liquid cooling systems. The effects of coolant flow rate, battery discharge rate, and cooling plate thickness and quantity on the heat dissipation performance of the liquid cooling system were investigated. Findings demonstrate that the topology-optimized cold plate system with four inlets and two outlets exhibits optimal heat dissipation performance. Increases in coolant flow rate, cold plate thickness, and quantity contribute to enhanced cooling performance of the liquid cooling system. Taking into account factors such as pump power consumption, system weight, and heat dissipation performance, a liquid-cooled system with three cold plates and an inlet flow rate of 2.5 × 10-6 m3/s is considered the optimal choice for cooling the battery pack in this study. Under the cooling of this cold plate system, at a coolant and ambient temperature of 25 °C and a discharge rate of 3C, the battery pack’s maximum temperature and temperature difference are 30.9 °C and 4.87 °C, respectively.

Analysis and design of module-level liquid cooling system for rectangular Li-ion batteries

To promote energy conservation and emission reduction, the electric vehicles (EVs) are developing rapidly. An effective battery thermal management system (BTMS) can extend the service life of batteries and avoid thermal runaway. In this study, a liquid-cooling management system of a Li-ion battery (LIB) pack (Ni-Co-Mn, NCM) is established by CFD simulation. The effects of liquid-cooling plate connections, coolant inlet temperature, and ambient temperature on thermal performance of battery pack are studied under different layouts of the liquid-cooling plate. Then, A new heat dissipation scheme, variable temperature cooling of the inlet coolant, is proposed. Results indicate that connecting two sets of liquid coolant plates in a 3-series, 1-parallel configuration can effectively reduce the maximum temperature of the battery pack from 48.73 ℃ to 30.75 ℃, while controlling the maximum temperature difference to 3.98 ℃ at the end of discharge. Simultaneously, the proposed cooling scheme reduces the maximum temperature difference within the battery pack by 36.09 % at the beginning of the discharge period. This study provides a valuable reference into advancing BTMSs of battery pack-level for EVs.

Temperature regulation for liquid-cooled fuel cell based on adaptive sliding mode control

The liquid cooling system (LCS) of the proton exchange membrane (PEM) fuel cell suffers from large time delay, coupling, uncertainties, and various disturbances, making it susceptible to temperature regulation overshoot and control oscillation. This article focuses on a composite control scheme for the LCS that has effectively addressed the aforementioned issues. We first propose a two-layer control approach for the pump to minimize coupling, and an average delay model (ADM) for radiator whose parameter uncertainties are removed by equilibrium optimizer (EO). To overcome disturbances, an adaptive sliding mode control (ASMC) based on extended state observer (ESO) is presented, and its finite-time convergence is demonstrated. Additionally, the indirect regulation for the stack temperature is designed to considerably reduce the time delay in the fan control loop. Co-simulation results indicate that the proposed ASMC significantly suppresses the chattering phenomenon compared with regular sliding mode control (SMC). In contrast to incremental fuzzy control, the proposed scheme possesses superiorities in response speed, tracking accuracy, anti-disturbance, as well as suppression of overshoot and oscillation.

Durable slippery liquid-infused porous surfaces for effective corrosion protection of aluminum alloy in ethylene glycol-water solutions

Aluminum (Al) alloys are extensively utilized in liquid-cooling heat dissipation systems owing to their superior strength-to-weight performance, ease of processing, and high thermal conductivity. However, they are susceptible to corrosion in the cooling medium, such as ethylene glycol-water solutions. This study presents a straightforward and cost-effective method to create a slippery liquid-infused porous surface (SLIPS) designed to effectively prevent corrosion of the 6061 Al alloy in ethylene glycol-water solutions. Micro/nano hierarchical structures were achieved on the SLIPS through plasma electrolytic oxidation and hydrothermal treatment. Following the modification of low-surface-energy materials and the infusion of silicone oil, the SLIPS exhibited an outstanding slippery property, allowing ethylene glycol-water droplets to effortlessly slide down the inclined surface at an angle of 1.1°. Additionally, the SLIPS demonstrated remarkable anti-corrosion performance against ethylene glycol-water solutions, with a minimum corrosion current density (Icorr) of 2.4 × 10−10 A·cm−2. Crucially, long-term immersion test results on corrosion resistance revealed that the SLIPS provided reliable corrosion protection for the 6061 Al alloy, exhibiting an Icorr increased by 4 orders of magnitude compared to a smooth substrate. These findings hold significant potential for advancing the widespread application of SLIPS in liquid-cooling heat dissipation systems.

A numerical investigation on a liquid-cooled battery thermal management system: Effect of inlet temperature and flow rate

Battery thermal management systems (BTMSs) and their stable operation are crucial for safety and efficiency of electrical vehicles. A BTMS utilized a cold plate is proposed in this paper for cooling of a cylindrical Li-ion Battery Pack (BP) arranged in 2×18 layout. The main focus of the study is on the effects of cooling fluid inlet temperature to cooling efficiency, and it is numerically investigated for 2C discharge rate at various flow rates from 0.1 to 1.0 l/min. The maximum temperature difference (ΔT max ) inside the BP and the maximum cell temperature (Tmax ) are analyzed via ANSYS Fluent software. Based on the comprehensive analysis of all system evaluation criteria, it can be concluded that the optimum flow rate is 0.5 l/min, and the optimum inlet temperature is 20 °C.

전기자동차 배터리 냉각 플레이트의 유동 형상에 따른 냉각 성능에 관한 연구

The performance of lithium-ion batteries in electric vehicles is significantly affected by temperature. To ensure battery stability and extend its lifespan, an effective cooling system must be developed for heat dissipation. Therefore, researchers are focusing on liquid-cooled systems that use fluids with higher thermal conductivities compared with conventional air-cooling systems. However, studies regarding the flow shapes of crucial cooling plates in indirect liquid-cooling systems are scarce. In this study, the optimal flow shape of cooling plates with high cooling performance for dissipating heat generated during battery charging and discharging is determined. Four models with different structural features are analyzed via computational fluid dynamics simulations and then validated experimentally. Model 1, which features a small stagnation region, exhibits better cooling performance compared with Model 2, which features smoother curved flow paths. Models with large stagnant regions demonstrate inferior cooling performance, which is attributed to the effect of heat absorption, based on the residence time of the coolant in the cooling plate. Improvement in cooling efficiency is confirmed, which implies the feasibility of applying the model to enhance the performance of electric vehicles in the future.

A novel hybrid liquid-cooled battery thermal management system for electric vehicles in highway fuel-economy condition

A hybrid liquid cooling system that contains both direct and indirect liquid cooling methods is numerically investigated to enhance the thermal efficiency of a 21700-format lithium-ion battery pack during the discharge operation. One of the most significant challenges that liquid-based direct cooling systems face is the filling of the heat capacity of the coolant during the cooling process, hindering the effective dissipation of heat generated from batteries. This paper aims to introduce a battery thermal management system to address this issue. In the present study, the influences of immersion and flow cooling methods using HFE-7100 and water (as working fluids), inflow velocities of cooling channel and tubes, parallel and counter flow, battery cell space, and highway fuel-economy test on the temperature distribution of batteries were studied comprehensively. Results highlight that immersion cooling with water outperforms due to the lower thermal conductivity of HFE-7100. In addition, Flow cooling significantly reduces the battery pack's highest temperature and non-uniformity compared to immersion. According to the numerical results, using cooling tubes as an indirect cooling system integrated with the direct flow cooling method can remarkably improve the thermal efficiency of the battery pack. Moreover, results exhibited that counterflow between cooling tubes/channels can keep the highest temperature and temperature variance of Li-ion battery package below 32.15 °C and 3.04 °C, respectively. Varying battery cell spaces shows that a 14 mm space reduces the battery package's highest temperature by 1.54 °C compared to a 10 mm space. Finally, highway fuel-economy condition is applied to the simulations of this study, illustrating the effect of an innovative hybrid battery thermal management system for a 21700-type Li-ion battery pack.

Experimental Design of High-Performing Open-Cathode Polymer Electrolyte Membrane Fuel Cells

Open-cathode polymer electrolyte membrane fuel cells (PEMFCs) utilize a unique air-cooled system design to eliminate the humidifiers, air compressor, and liquid cooling loop of conventional, liquid-cooled PEMFC systems, thereby greatly reducing system cost. However, the open-cathode PEMFC performance is restricted by poor humidification, high membrane and charge transfer resistances, and overheating due to inefficient thermal and water management. This work aims to strategically modify the membrane electrode assembly (MEA) design to overcome these issues and achieve high open-cathode PEMFC performance that approaches that of liquid-cooled systems. The use of thinner membrane along with short side chain ionomer is found to elevate the cell performance due to increased water retention at the cathode catalyst layer (CCL) and decreased ohmic losses. Thinner gas diffusion layers with high porosity enable additional cell performance increment by improving oxygen availability at the CCL. An overall current density rise of 88% at 0.6 V and 53% at 0.4 V is achieved by the strategically designed MEA for open-cathode cells. The enhanced power density enabled by the custom MEA can both reduce the stack cost and expand the power range of open-cathode PEMFCs, thus expanding their potential use for low-cost fuel cell system applications.

Sensitivity Analysis and Optimization of a Liquid Cooling Thermal Management System for Hybrid Fuel Cell Aircraft

The objective of this work is to perform a comprehensive system analysis of a liquid-cooling thermal management system for a hybrid-electric aircraft using fuel cells for general aviation by sizing and optimizing the system with respect to a given objective. A sensitivity analysis on the different design parameters and model assumptions is also performed and their impact on the aircraft and its performances will be assessed. Firstly, the case study is defined and an optimization is run with some initial assumptions leading to a feasibility study for the implementation of this system. The sensitivity analysis is then undergone for the chosen coolant type and fuel cell stack temperature selected after the first optimization. Incorporating the findings of this analysis, a second optimization is run on the thermal management system with improved inputs in order to demonstrate a scenario with reduced penalty on the aircraft. Preliminary results show that implementing this hybrid propulsion system along with its thermal management is feasible with a reduction in payload and range. In addition, it can be concluded that initial assumptions and design choices are shown to have a significant impact on the system’s sizing and should be considered in aircraft sizing design loops.

Experimental study on the bionic microchannel heat sink integrated with a piezoelectric pump

The increased integration of electronic chips and the miniaturization of electronic products significantly raise the heat generated by electronic devices. To meet the cooling requirements of highly integrated electronic devices and enhance the cooling performance of the piezo-driven cooling system, a piezo-driven microchannel liquid-cooling system for CPU chip cooling was developed. The system integrated a bionic microchannel heat sink and a piezoelectric pump with umbrella valves (PP-UV). The piezoelectric pump was used as the driving source to propel the coolant flow, and the output of the piezoelectric pump pulsated, contributing to the convective heat transfer of the fluid in the microchannel. The spider web microchannel heat sink (SWM-HS) was designed and compared with the tandem Y-shaped microchannel heat sink (T-YMHS). The performance of the piezo-driven microchannel heat sink system with different structured microchannel heat sinks was studied by combining experimentation and simulation. The results indicated that the SWM-HS cooling system exhibited better fluid transmission and cooling characteristics, along with lower input power (3.32 mW). When the drive voltage was 100 V, the output flow of the SWM-HS cooling system was 56.4 mL/min. With a thermal power consumption of 30 W, the CPU temperature remained stable at approximately 55 °C, while the total thermal resistance measured 0.183 °C/W. In comparison with T-YMHS, the internal pressure drop of the SWM-HS decreased by 20.7 %, the Nusselt number increased by 13.7 %, and it achieved a cooling efficiency of 64.48 %. The experimental results aligned well with the simulation results. This work contributes to advancing the application of piezoelectric devices in electronic cooling and enhancing the cooling efficiency of miniature cooling systems.

Numerical investigation and parameter optimization on a rib-grooved liquid-cooled plate for lithium battery thermal management system

To increase the effectiveness of liquid-cooled battery thermal management systems (BTMS) in electric vehicles, a unique liquid-cooled plate with a discrete, inclined, and alternating arrangement of ribs and grooves inside the plate was invented during this study. A numerical study was carried on to analyze the thermal performance between this rib-grooved liquid-cooled plate and a conventional straight-channel one. Firstly, a battery module's 1D/3D electrochemical-thermal coupled model was constructed to analyze the thermal performance in the case of actual electrochemical heat production. Then numerical results were obtained by solving this coupled model with different plates. The results indicated that ribs effectively equalize the flows between different channels and multiple longitudinal swirl flows are formed due to grooves, which improves the liquid-cooled system's temperature control performance with a small increase in pressure drop. The maximum battery temperature is 0.74 °C lower, the temperature standard deviation of the contact surface is 0.18 °C lower, and the pressure drop is 55.37 Pa higher in the BTMS with the rib-grooved liquid-cooled plate than it is in the conventional one. After that, an orthogonal design of experiments was used to investigate the effect of four features, including rib-groove tilt angle, column spacing, row spacing, and rib-groove length, on the thermal performance and energy consumption of the battery module. The optimum structure of the rib-grooved liquid-cooled plate is obtained through range analysis: the rib-groove inclination angle is 45°, the row spacing is 13.5 mm, the column spacing is 11.5 mm, and the rib-groove length is 9 mm. This research on the rib-grooved liquid-cooled plate offers a fresh concept that considerably enhances its capacity to regulate the temperature of the liquid-cooled BTMS.

Review of Thermal Management Strategies for Cylindrical Lithium-Ion Battery Packs

This paper presents a comprehensive review of the thermal management strategies employed in cylindrical lithium-ion battery packs, with a focus on enhancing performance, safety, and lifespan. Effective thermal management is critical to retain battery cycle life and mitigate safety issues such as thermal runaway. This review covers four major thermal management techniques: air cooling, liquid cooling, phase-change materials (PCM), and hybrid methods. Air-cooling strategies are analyzed for their simplicity and cost-effectiveness, while liquid-cooling systems are explored for their superior heat dissipation capabilities. Phase-change materials, with their latent heat absorption and release properties, are evaluated as potential passive cooling solutions. Additionally, hybrid methods, such as combining two or more strategies, are discussed for their synergistic effects in achieving optimal thermal management. Each strategy is assessed in terms of its thermal performance, energy efficiency, cost implications, and applicability to cylindrical lithium-ion battery packs. The paper provides valuable insights into the strengths and limitations of each technique, offering a comprehensive guide for researchers, engineers, and policymakers in the field of energy storage. The findings contribute to the ongoing efforts to develop efficient and sustainable thermal management solutions for cylindrical lithium-ion battery packs in various applications.