Cylindrical Power Battery Research Articles

Analysis and optimization of thermal management system for cylindrical power battery based on distributed liquid cooling plates

Analysis and optimization of thermal management system for cylindrical power battery based on distributed liquid cooling plates

Promotion of practical technology of the thermal management system for cylindrical power battery

Amidst the industrial transformation and upgrade, the new energy vehicle industry is at a crucial juncture. Power batteries, a vital component of new energy vehicles, are currently at the forefront of industry competition with a focus on technological innovation and performance enhancement. The operational temperature of a battery significantly impacts its efficiency, making the design of a reliable Thermal Management System (TMS) essential to ensure battery safety and stability. Cylindrical power batteries are widely utilized in the industry. This article outlines the four main structures and their drawbacks of TMS for cylindrical power batteries. Among these structures, air cooling falls short in meeting high heat dissipation requirements. Liquid cooling is expensive, intricate, and adds considerable weight. Phase Change Materials (PCM) are not yet prevalent in practical applications. Similarly, heat pipes are relatively uncommon in large high-power battery packs. To better align with the new energy vehicle industry’s demands for top-notch performance, cost-effectiveness, eco-friendliness, and reliability, this paper strongly recommends delving deeper into composite cooling solutions. The construction of an economically viable and fully optimized composite cooling method is poised to become a significant scientific challenge for future research endeavors.

Experimental study of a novel strategy to construct the battery thermal management module by using tubular phase change material units

For the thermal management of cylindrical power battery module, the classical cuboid-like phase change material (PCM) module still remains problematic, because the bulky structure remarkably decreases the energy density and secondary heat-dissipation capability of the battery module. Here a novel strategy to construct the PCM module was proposed by substituting the bulky cuboid PCM module with tubular PCM units. Compared to the classical cuboid module, the assembled tubular PCM module confers numerous naturally-formed channels for air flow, an enlarged outer surface area for secondary heat dissipation, and a greatly reduced module weight. As a result, the tubular PCM module demonstrates a superior heat-dissipation performance for cylindrical power batteries. For example, with forced air convection, the temperature and temperature difference can be controlled below 47.2 and 1.0 °C respectively under an extreme working environment, i.e., 10 charge and discharge cycles at a high environment temperature of 40 °C. More importantly, this novel strategy also benefits the flexible assembling and maintenance of the modules, and saves 54% of the PCM amount, thus increasing the energy density of the battery module from 75.5 to 94.4 Wh kg−1.

Thermal performance of PCM and branch-structured fins for cylindrical power battery in a high-temperature environment

Battery modules with phase change material (PCM) cooling inevitably suffer from heat-storage saturation and poor secondary-heat dissipation, especially in high-temperature environments or hot regions. To optimize thermal management, this study firstly explores the thermal behaviors of PCMs with different phase change temperatures (PCTs) in a high-temperature environment. The experimental results show that a PCM with a PCT of 46 °C offers the best cooling effect at a high ambient temperature of 40 °C in this study. For example, the maximum temperature of a cell without PCM reaches 53.3 °C, whereas that of the cell with PCMs having PCTs 40, 46, and 55 °C, are 59.2, 51.6, and 57.5 °C, respectively, during the dynamic cycling process. Nevertheless, the application of above PCM is still unsatisfying because the maximum temperature of the battery in the PCM module exhibits obvious increasing trend with cycles in 40 °C environment. On this basis, several novel fins with multiple heat-flow channels (of V, Y and X shapes) are designed and introduced into the PCM module to enhance the secondary heat dissipation capability. These fins with innovative branch structures deliver excellent performance in alleviating the battery temperature than the traditional rectangular fins, which can be attributed to the ability of the branch structures to increase the heat transfer area by adding heat transfer channels. The results of this work show that the X-shape delivers the best performance in a high-temperature environment of 40 °C by maintaining the maximum temperature of the cell below 47 °C.

Optimization of liquid cooling technology for cylindrical power battery module

Liquid cooling technologies for large battery modules are facing challenges of optimizing their structure due to the many variable factors. In this work, a simplified yet effective strategy coupling single-factor analysis with orthogonal test is proposed to overcome this barrier in large battery modules. We systematically study the influence of the inlet velocity, channel number and contact angle on the cooling performance and thereby optimize the structure. The influence rank of the factors follows the order of “contact angle” > “inlet velocity” > “channel number”, indicating that the contact angle has the most significant influence on the cooling performance, which should be fixed at about 70°. Channel number shows slight influence on the cooling performance in large battery modules. The suitable values of the inlet velocity and channel number are variable within the ranges of 0.2–0.5 m·s−1 and 1–2, respectively, based on different specific applications, particularly those targeting higher cost-efficiency.

An experimental and numerical examination on the thermal inertia of a cylindrical lithium-ion power battery

Thermal issues are increasingly critical for the scaling-up and integrated deployment of lithium-ion batteries (LIBs). To make battery temperature control more accurate, a concept of thermal inertia was proposed to cylindrical power batteries in the current study. Experimental results showed that the thermal inertia of the battery can greatly affect the thermal behavior during battery discharging process, based on which a battery thermal model was created by COMSOL Multiphysics with infrared imaging technology adopted to experimentally investigate the thermal inertia for a LiFePO4 (LFP) battery. It is evidenced that the model and the corresponding simulation can provide helpful guidance for the thermal behavior control and improve thermal performance. Furthermore, the temperature distribution and variation of the slack period (after discharge) were studied, including internal temperature, surface temperature and temperature difference. Results showed that the battery radius (R) and discharge rate (C) were the major factors that influenced the thermal inertia. In addition, a thermal inertial calculation model was proposed for predicting battery thermal inertia under different operating conditions.

Numerical analysis and experimental visualization of phase change material melting process for thermal management of cylindrical power battery

Organic phase change materials (PCMs) have been of increasing interest in battery thermal management due to their high latent heat and excellent cycling stability. This paper reports both numerical analysis and visualization experiments for the melting process of paraffin PCM surrounding a cylindrical power battery. Specifically, two different housing materials are considered, one made of metal and the other made of acrylics. For the metal housing case, the PCM exhibits a melting front isolated both from the battery and housing wall with accelerated melting in the B∼C stage, accounting for the isothermal temperature plateau observed in both the numerical modeling and experimental measurements. For the acrylic housing case, the unmelted PCM instead adheres to the inner wall of housing all the way, melting at the rate slower than the metal housing case. In both housing cases, the numerically predicted liquid fractions are found to agree with our experimentally visualized results. The battery top to bottom temperature variation is also examined with regard to the melting process. Moreover, the instantaneous Nusselt number is obtained to identify the different heat transfer characteristics in the different melting stages.

Experimental study on the thermal management performance of phase change material coupled with heat pipe for cylindrical power battery pack

The battery thermal management technology is vital for the development of new energy vehicles. In order to understand the performance of the phase change material/heat pipes (PCM/HP) coupled thermal management system for cylindrical power battery, an PCM/HP coupled BTM module was designed and tested experimentally in detail. The results showed that the effect of temperature control based on PCM is improved comparing to air-based BTM under natural convection. The maximum temperature of PCM/HP coupled BTM can be controlled below 50°C for longer time than those of the air-based case and PCM-based case under the same conditions. The temperature difference can be reduced about 33.6% through filling PCM and it can progress a decline of 28.9% further through embedding HP into the PCM. The maximum temperature difference of PCM/HP coupled BTM can be controlled below 5°C for longer time than those of the two other cases, air-based BTM and PCM-based BTM. It is almost the same in the first 620s under different velocities, which are all less than 5°C.

Numerical analysis of phase change materials for thermal control of power battery of high power dissipations

Solid-fluid phase change materials have been of increasing interest in various applications due to their high latent heat with minimum volume change. In this work, numerical analysis of phase change materials is carried out for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density is applied at the battery cell, which is surrounded by phase change material (PCM) of paraffin wax type and contained in a metal housing. A two-dimensional geometry model is considered due to the model symmetry. The effects of power densities, heat transfer coefficients and onset melting temperatures are examined for the battery temperature evolution. Temperature plateaus can be observed from the present numerical analysis for the pure PCM cases, with the temperature level depending on the power densities, heat transfer coefficients, and melting temperatures. In addition, the copper foam of high thermal conductivity is inserted into the copper foam to enhance the heat transfer. In the modeling, the local thermal non-equilibrium between the metal foam and the PCM is taken into account and the temperatures for the metal foam and PCM are obtained respectively.

Thermal management of cylindrical power battery module for extending the life of new energy electric vehicles

Thermal management especially cooling plays an important role in power battery modules for electric vehicles. In order to comprehensively understand the heat transfer characteristics of air cooling system, the air cooling numerical simulation battery models for cylindrical lithium-ion power battery pack were established in this paper, and a detailed parametric investigation was undertaken to study effects of different ventilation types and velocities, gap spacing between neighbor batteries, temperatures of environment and entrance air, amount of single row cells and battery diameter on the thermal management performance of battery pack. The results showed that the local temperature difference increased firstly and then decreased with the increase of wind speed. Reversing the air flow direction between adjacent rows is not necessarily appropriate and the gap spacing should not be too small and too large. It is prone to thermal runaway when the ambient temperature is too high, and the most suitable value of S/D (the ratio of spacing distance between neighbor cells and cell diameter) is gradually reduced along with the increase of cell diameter.

Simulation of heat dissipation with phase change material for cylindrical power battery

AbstractIn order to better understand the heat dissipation performance of power battery for electrical vehicles, a three-dimensional model based on phase change material (PCM) cooling for individual cylindrical battery cell has been developed. The model takes into account the effects of unsteady heat generation, internal conduction and external natural convection to investigate the temperature response and distribution. The simulation results showed that the PCM with thermal conductivity higher than 0·8 W m−1 K−1 can be used for keeping the maximum temperature below 50°C in a battery cell under a constant heat generation rate of 170 000 W m−3. The unsteady discharge simulated results demonstrated that the heat transfer coefficient was another important factor for heat transfer enhancement. The PCM based power battery thermal management system indicated effective cycle application because the PCM can store most of the thermal energy during discharge and release it to the outer air during charge or non-star...