Cylindrical Lithium-ion Battery Research Articles

Investigation on the temperature control performance and optimization strategy of a battery thermal management system combining phase change and liquid cooling

For ensuring the safety of lithium-ion batteries in application, keeping the temperature of the battery pack in the desired range is crucial under different operating condition. This paper incorporates experiments and the numerical model to design a novel thermal management system with the combination of the phase change material and liquid cooling for twelve cylindrical lithium-ion batteries. The experimental results reveal that at the ambient temperature of 35 °C, the maximum temperature and temperature difference of the blank control system during 1 C charge and 2 C discharge are 57.6 °C and 4.1 °C, while the maximum temperature difference is 3.6 °C with single liquid cooling. Compared with them, the maximum temperature of the coupled system is only 44.8 °C and the maximum temperature difference is less than 2 °C with superior cycling performance. Moreover, an electric-thermal model is proposed to study the cooling effect of coolant, from which controlling the coolant flow within 250 mL/min is the best choice. Based on these results, an optimization strategy of hierarchical management is proposed for the coolant flow and inlet temperature by monitoring the maximum temperature of the battery pack and ambient temperature. This strategy not only controls the temperature of the system in desired range under different ambient temperatures, but also reduces the unnecessary energy consumption of liquid cooling. The proposed system is scalable to be applied to the other types of batteries for thermal management.

Novel procedure to determine the stress-strain relation of Lithium-ion Batteries through indentation test

This study proposes a novel approach to convert the load–depth curve measured in the experimental indentation test into stress–strain curves. Due to the lack of the tensile test results for the cylindrical lithium-ion battery (LIB) cell, a combination of the analytical analysis and the inverse optimization approach is first conducted as a reference point to determine the elastoplastic constitutive equation, which can predict the response of cylindrical LIB cell cells under the cylindrical indenter. The obtained load-depth curves from the robust optimization algorithm are in good agreement with the experimental loading–unloading curves. This novel approach includes a new definition of the contact area between the cylindrical indenter and the cylindrical LIB cell. Finite element models validate the measured contact area values from the analytical approach. The analytical approach in this study can accurately capture the stress–strain curve validated with optimization results. Afterward, different single indentation tests are conducted to estimate the reduction of Young’s modulus through the increasing indentation depth. Noteworthy, a definition of the indentation strain can physically interpret the indentation strain in the case of two crossed cylinders. The cell voltage is measured during the indentation test to detect the internal short circuit in the LIB cell. In homogenized modeling, the damage of the LIB cell is considered, which is an essential indicator of the internal short circuit of a LIB cell and possible thermal runaway.

Analytical solution, optimization and design of a phase change cooling pack for cylindrical lithium-ion batteries

Due to the world’s transition to clean energy, the utilization of energy and power storage systems such as lithium-ion batteries has been widely welcomed. The most crucial problem of using these batteries is the large amount of heat production during their operation, which can affect their correct function. Many methods have been investigated to manage and control the temperature of these batteries. One of these methods is to employ phase change materials (PCMs). Despite numerous experimental and numerical studies about cylindrical lithium-ion batteries, there is still a gap in an analytical solution for PCM-based thermal management of them. In the present study, the cooling process of 18650 cylindrical lithium-ion batteries through PCM has been analytically investigated in cylindrical coordinates. For this purpose, the exact solution of the phase transition in cylindrical coordinates is generalized and coupled with the thermal resistance method for the cooling process of this type of battery. In this solution, the temperature distribution in both solid and liquid phases has been considered. Also, the effect of two different types of PCM, namely calcium chloride hexahydrate (PCM1) and paraffin wax (PCM2), and parameters such as ambient temperature, rate of charge/discharge, and thermophysical properties of the PCM on the battery cooling process have been investigated. Moreover, the effect of considering cell internal temperature field and natural convection of the liquid PCM has been evaluated. The results show that for PCM1 in discharge rates of 2C, 4C, and 6C the corresponding required PCM thicknesses are 1.5, 3.1, and 3.8 mm, respectively. In addition, their temperature rises are 2.4, 3.7, and 4.6 °C, in their maximum operation times, respectively. Also, since the thermal conductivity of PCM1 (ks=1.008, kl=0.561W/(m.K)) is higher than that of the PCM2 (ks=0.21, kl=0.18W/(m.K)), the temperature rise in the cell is about 6 °C lower when the former is applied for a single cell. Eventually, the obtained results are generalized for the design of the optimal battery pack which contains 18650 cells surrounded with PCM.

Thermal performance assessment for an array of cylindrical Lithium-Ion battery cells using an Air-Cooling system

Modern society depends on energy storage systems like Lithium-ion (Li-ion) batteries. Li-ion battery cells are delicate to changes in temperature. Extreme environmental conditions affect their life cycle and performance. Therefore, effective cell temperature management is a must for secure and dependable battery operation. Additionally, the high production costs of electric cars must be countered by the adaptability of the battery pack design for modern electric vehicles. As the chemical reactions generate more heat and raise the battery's temperature, it may cause the battery to explode and cause fires in the workplace. To address this issue, the present work attempts to numerically study a novel design of an efficient air-cooling system for improving the performance of lithium-ion batteries by reducing the operational temperatures under a different coolant flow rate. The main output of the presented study is the analysis of a novel design of an efficient air-cooling system for lithium-ion batteries. The study aims to reduce the operational temperatures of the batteries under different coolant flow rates to improve their performance and service life. The numerical simulations are carried out using a finite volume-based computing tool with the K-epsilon (k-ε) turbulence model. The analysis is performed for various pertinent parametric ranges, including the spacing between the batteries, Reynolds numbers, and average Nusselt numbers. The results indicate that increasing air inlet velocity (Re) substantially reduces the average air temperature of the cooling pack and temperature difference (ΔT) of the battery cells, and the cooling pack's average heat transfer rate (Nu) increases monotonically as the Re increases.

Performance Analysis of an Innovative PCM-Based Internal Cooling Design for Cylindrical Lithium-Ion Battery Considering Compact Structure and Uniform Temperature

Performance Analysis of an Innovative PCM-Based Internal Cooling Design for Cylindrical Lithium-Ion Battery Considering Compact Structure and Uniform Temperature

Effect of mechanical vibration on phase change material based thermal management system for a cylindrical lithium-ion battery at high ambient temperature and high discharge rate

The performance and safety of lithium-ion batteries (LIB) in electric vehicles (EV) depend strongly on the operating temperature, so an effective battery thermal management system (BTMS) is essential. Battery thermal management (BTM) technology based on phase change material (PCM) is currently considered to be one of the most promising approaches. Electric vehicles are inevitably affected by vibration during operation, and many studies have shown that mechanical vibration can enhance natural convection heat transfer. The effect of mechanical vibration on the PCM-based battery thermal management module of a single cylindrical lithium-ion battery at high ambient temperature and high discharge rate is studied by numerical simulation for the first time in this paper. N-octadecane is selected as the PCM application in the cylindrical battery's periphery. The results show that: (1) mechanical vibration enhances the heat transfer of natural convection to limit the excessive temperature rise and improve temperature uniformity of the lithium-ion battery, and when the PCM is 12 mm, the mechanical vibration has the most significant impact on the PCM-based BTMS (2) when the vibration frequency is 10 Hz, the cooling effect of the battery thermal management module is the best, which is 28.05% lower than when there is no vibration. when the vibration frequency is 50 Hz, the temperature uniformity of the battery is the best, with a maximum temperature difference of 3.86 K. (3) when the vibration amplitude is 100 mm, the maximum temperature difference of the battery is 1.89 K, and the maximum temperature decreases by 27.74%. This study provides a new perspective for the thermal management system of lithium-ion batteries for electric vehicles.

Numerical analysis of cylindrical lithium-ion battery thermal management system based on bionic flow channel structure

To improve the thermal and flow performance of the battery thermal management system (BTMS), a heat exchanger with a bionic flow channel structure was designed and applied to a cylindrical lithium-ion battery module in this work. To accurately reflect the transient thermal behavior of the battery, a battery thermal model was obtained by experimentally collecting thermodynamic parameters. A computational fluid dynamics model of the BTMS was established. The influences of different bionic flow channel structure parameters on the thermal performance of the BTMS were investigated by a multi-factor optimization analysis. In addition, the thermal performance was also compared with that of a heat exchanger with a bionic honeycomb-like structure and a traditional helical structure. The results show that at the optimum structural parameters, the maximum temperature, maximum temperature difference, and pressure drop of the BTMS were calculated as 302.656 K, 3.726 K and 29.69 Pa respectively. For the same volume fraction and geometrical parameters, the heat exchangers with a spider web-like structure has better thermal and flow characteristics than honeycomb-like and traditional helical structures.

Towards Determining an Engineering Stress-Strain Curve and Damage of the Cylindrical Lithium-Ion Battery Using the Cylindrical Indentation Test

Mechanical internal short circuit (ISC) is one of the significant safety issues in lithium-ion battery design. As a result, it is possible to subject LIB cells to thorough mechanical abuse tests to determine when and why failure may occur. The indentation test is a recommended loading condition for evaluating mechanical damage and ISC. In this study, 18,650 cylindrical battery cells underwent indentation tests and a voltage reduction following the peak force identified by the ISC. Due to the complexity of the contact surface shape between two cylinders (LIB cell and indenter), a new phenomenological analytical model is proposed to measure the projected contact area, which the FEM model confirms. Moreover, the stress-strain curve and Young’s modulus reduction were calculated from the load-depth data. In contrast to previously published models, the model developed in this paper assumes anisotropic hyperelasticity (the transversely isotropic case) and predicts the growing load-carrying capacity (scalar damage), whose variation is regulated by the Caputo-Almeida fractional derivative.

Numerical investigation of a compact and lightweight thermal management system with axially mounted cooling tubes for cylindrical lithium-ion battery module

To construct a compact and lightweight cooling system for cylindrical batter module, developing cooling tubes inserted into spaces between batteries is a promising way. Yet, the constant distance kept between adjacent cells in battery array makes the reported weight ratio values not satisfactory enough. Merits and demerits between different battery arrangement modes (staggered and aligned) are also unclear. Therefore, in this work, a novel liquid cooling thermal management system with axially mounted cooling tubes inserted into spaces between tightly assembled batteries is presented to provide a compact and lightweight solution to the cooling of cylindrical battery module. Designs with staggered and aligned battery arrangements are compared. Corresponding results show that design with staggered battery arrangement is superior to the aligned one based on the trade-off of different design requirements including cooling performance, system weight and volume cost. BTMS with staggered design reports a remarkably high performance in terms of the lightweight extent, which only accounts for 5.4 wt% of the battery module, much lower than those in previous studies. Further, extended studies are performed for the optimization of BTMS with staggered battery arrangement and the results could provide useful guidance in the future design of BTMS for cylindrical battery modules.

Experimental studies of reciprocating liquid immersion cooling for 18650 lithium-ion battery under fast charging conditions

In this study, the reciprocating liquid immersion cooling has been proposed and tested for cooling the cylindrical lithium-ion battery (LIB) under fast charging conditions. First, the temperature responses of LIB under fast charging conditions with liquid immersion cooling and natural convection are compared. Experimental results show that the reciprocating liquid immersion cooling possesses better heat dissipation performance than natural convection, not only can precisely control the cell temperature to around 50 °C during fast charging, but also can improve the cell temperature uniformity. Meanwhile, the reciprocating system enables rapid cooling of the battery during the resting process, which consequently achieves asymmetric control of high-temperature charging and room temperature discharging. Then, the effects of different charging rates and different charging protocols are explored, and the high-speed photography is used to observe and record the liquid-gas phase transition phenomenon under three different charging rates. Finally, the temperature response and energy consumption analysis of LIB in the fast-charging process with three different assembly schemes are investigated. This study provides preliminary proof for the advantage of applying liquid immersion cooling for LIB under fast charging.

Research on thermal runaway process of 18650 cylindrical lithium-ion batteries with different cathodes using cone calorimetry

The complex chemical reactions and the safety properties of lithium-ion batteries (LIBs) with different cathode materials are various from each other. In this article, a cone calorimeter was used to measure the mass change, heat generation and gas release characteristics of three types of 18650 cylindrical LIBs with lithium iron phosphate (LFP), lithium cobalt oxide (LCO) or lithium nickel manganese cobalt oxide (NMC) as the positive electrode material. All samples were tested under 9 kinds of conditions combined state of charge (SOC) of 33 %, 66 %, 100 % with heat flux of 30 kW/m2, 45 kW/m2, 60 kW/m2, respectively. Especially, the principal component analysis (PCA) method was applied to further analyze the difference of thermal runaway (TR) behavior for the three kinds of batteries. Moreover, the influence of SOC and heat flux on the safety features of 18650-cylinder LIBs was analyzed. After comparing parameters such as mass loss rate (MLR), gas generation/consumption, heat release, toxicity among the tested 18650 cylindrical LIBs, the results displayed that the influence of external heat flux on the intensity of battery TR reactions was lower than that of SOC. The TR risk of LCO and NMC batteries with relatively high SOC was higher than that of LFP ones in large fire scenarios. When the fire scale was relatively small, the main factor that determined the risk of battery fire was the type of cathode, while which became SOC under the opposite situation of large-scale fire. PCA results showed that LFP and NMC batteries presented almost completely different TR characteristics, which could provide important references for battery design, corresponding fire investigation and attack.

Evaluating the heat generation characteristics of cylindrical lithium-ion battery considering the discharge rates and N/P ratio

Although lithium-ion batteries (LIBs) have received more attentions as the increasing number of new energy vehicles, in-depth exploration for the heat generation characteristics of LIBs during operation remains challenging. This paper establishes an electrochemical-thermal model (ETM) to evaluate the heat generation characteristics of cylindrical LIBs considering the discharge rates and the ratio of negative to positive electrode capacity (N/P ratio). To ensure a wider range of research on thermal characteristics of LIBs, the proposed ETM is validated based on the experimental data under the ambient temperature of 25 °C and 35 °C. Subsequently, the distribution profiles of heat generation characteristics of LIBs under different conditions are numerically investigated. More innovatively, the effects of different discharge rates and N/P ratios on battery heat generation are comprehensively analyzed. The results show that the heat generation in the negative electrode occupies a major part and the influences of reversible term on the total heat generation of LIB cell cannot be ignored, especially at low discharge rates. Additionally, it is found that the proper selection of N/P ratio can improve the total heat generation of LIBs, which is helpful for optimizing performance in the early stages of battery design and thermal management.

Simulation Study on Heat Generation Characteristics of Lithium-Ion Battery Aging Process

Lithium-ion battery heat generation characteristics during aging are crucial for the creation of thermal management solutions. The heat generation characteristics of 21700 (NCA) cylindrical lithium-ion batteries during aging were investigated using the mathematical model that was created in this study to couple electrochemical mechanisms, heat transfer, and aging loss. These findings indicate that, at the same operating current, the heat generation power of the cell increased significantly with battery aging. This increase was primarily due to the energy loss caused by the growth of the solid–electrolyte interface (SEI) and a reduction in the negative porosity and other physical characteristics of the SEI, such as its ionic conductivity and molar volume, which also had an impact on the heat generation power. By investigating the variations in battery heat generation in different aging modes, the electrochemical mechanisms underlying the effects of aging on battery heat generation can be comprehended in depth.

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.

Improving the cooling performance of cylindrical lithium-ion battery using three passive methods in a battery thermal management system

Developing a high-performance battery thermal management system (BTMS) to keep the temperature of lithium-ion battery (LIB) in a suitable range has become of great interest for electric vehicle (EV) applications. Hence, this study has been set out to design a BTMS by utilizing various combination of phase change material (PCM), metal foam, and fins that keeps the battery surface temperature at the lowest level in normal and harsh environmental conditions under discharging with 3C current rate. Considering these three passive methods, four different cases of BTMS have been designed separately. Moreover, the effects of various fin shapes including rectangular, triangular, trapezoidal, I-shape, and wavy fins are studied for the optimum BTMS. The two-equation local non-equilibrium thermal model has been used which is more precise than the traditional thermal equilibrium model in simulating heat transfer between the PCM and metal foam. The numerical results demonstrated that the optimum BTMS, which is the combination of PCM, metal foam, and fins (fourth case), can reduce the battery surface temperature by 3 K. Furthermore, the maximum delay of about 470 s in melting of the PCM has been reported for this case. Additionally, the applied fins in the fourth case are acting as a network of heat sources to spread heat in the middle of the system, and utilized metal foam can create a uniform distribution of heat between LIB and ambient. Analyzing the effect of different fin shapes on the performance of optimum BTMS showed that there are no remarkable changes between the battery surface temperature of various fin shapes and it would be hard to find a suitable shape of fins for all environmental conditions.

Dynamic Crushing Behaviors of Cylindrical Lithium-Ion Battery Under Multiple Impacts: An Experimental Study

Abstract To understand the dynamic failure mechanisms of cylindrical lithium-ion battery (LIB) under different impact loadings, the crushing behaviors of 18650 LIBs were experimentally investigated in this work. The drop weight impact tests with different impactor heads were conducted to analyze the crushing responses of the LIBs. By changing the state of charge (SOC) of the battery, impactor types, and impact energy, the force-electric responses of a LIB under multiple impacts were explored. Macro- and micro-deformation of the batteries were further studied including SOC dependency and the failure modes of the separator. Results show that except for impact energy, the mechanical responses and failure behaviors of the LIBs under repeated impacts also depended upon the SOC and impactor types. The relationship between impact velocity and the minimum impact times was established when a hard internal short circuit (ISC) appeared to evaluate the dynamic safety of the LIBs. These results can provide guidance for the crashworthiness design and safety assessment of the batteries under multiple impacts.

Thermal management and temperature uniformity enhancement of cylindrical lithium-ion battery pack based on liquid cooling equipped with twisted tapes

BackgroundThe technology of lithium-ion batteries is adopted as a brilliant energy source for electric vehicles because of its outstanding benefits, such as constant power, long shelf life, lightweight, fast and safe charging, etc. A channeled liquid cooling system is one of the forceful techniques in the thermal management of battery packs. MethodsA cooling system equipped with diverse configurations of twisted tapes is established for a battery module consisting of sixteen commercial ICR18650–26 J lithium-ion batteries. First, the effects of the specific design factor of twisted tapes are investigated. Then to improve the temperature uniformity of the module, nonuniform patterns of twisted tapes are introduced. Significant FindingsThe corresponding findings corroborate the effectiveness of using twisted tapes. It is found that the maximum battery temperature can be controlled at around 305 K when the number of twist pitches is seven. However, the results express that the performance changes are not noticeable for increasing this parameter by more than five. It is ascertained that the cooling system with nonuniform twisted tapes is superior to the conventional case. The temperature difference in the battery module is stabilized within 11.25 K by using the twisted tape having an intensified ratio of 1.5.

Thermal performance of a hybrid thermal management system based on the half helical coil coupled with air jet cooling for cylindrical Lithium-ion battery

The Battery Thermal Management System (BTMS) is crucial for the efficient and safe operation of Lithium-ion batteries (LIBs). It is challenging for liquid cooling to apply to areas of battery modules with complex surface forms, such as the positive and negative cell terminals, cell holders, etc. Herein, the thermal management scheme integrated with the half helical coil and air jet impingement is proposed for cylindrical LIBs. Heat is transferred from the LIBs' sides by helical flow and dissipated from the LIBs' ends by air jet impingement. The three-dimensional computational fluid dynamics model of battery modules with cell holders is developed. The thermal performance of the LIBs at various BTMS strategies, the number of turns of the helical coil, airflow inlet velocity, inlet temperature, and contact resistance are investigated. When the impinging air jets are arranged on both ends of the cylindrical form, the maximum values of temperature difference (ΔT) of the LIBs fall from 5.7°C to 4.0°C compared with that of liquid-based BTMS. The arrangement of the half helical duct divided into two separate sections reduces the coolant flow path length, which decreases the maximum temperature (Tmax) and ΔT to 28.9°C and 3.6°C. The proposed BTMS exhibits an enhanced heat dissipation performance and provides a design guideline for developing the hybrid BTMS.

Passive thermal management system of lithium-ion batteries employing metal foam/ pcm composite for the development of electric vehicles

ABSTRACT Electric vehicles with a pack of lithium-ion batteries (LIBs) are taking a significant place in the field of transportation. Since lithium-ion battery efficiency relies on battery pack temperature, the temperature of the battery pack must be maintained within the safe limits for proper working of the system. This paper proposes a novel experimental method to dissipate and maintain the thermal energy emitted by LIBs based on a nickel foam/paraffin composite and a composite of copper foam/paraffin for thermal management of Panasonic NCR 18650B cylindrical lithium-ion battery cells. The results indicate that the surface temperature of the battery is reduced by 30.95% by comparing with ambient air convection and 24% temperature reduction by comparing with PCM by the application of nickel foam at a 2C discharge rate. By using copper foam/paraffin composite 34% and 25% temperature reduction by comparing with ambient air convection and PCM (paraffin) accordingly was achieved at a 2C discharge rate. Additionally, the result of temperature uniformity on the thermal management of the battery pack was also studied.

Thermal management scheme and optimization of cylindrical lithium-ion battery pack based on air cooling and liquid cooling

Battery thermal management system (BTMS) ensures the batteries work in a safe and suitable temperature range. In this study, a hybrid BTMS based on air cooling and liquid cooling is proposed. The heat generated by the battery is transferred to the coolant by heat conducting blocks (HCBs) which are evenly spaced along the axial direction of it to maintain the normal operation of the battery pack. Air cooling is then introduced to maintain the battery's temperature uniformity at the battery pack's edge. A three-dimensional simulation model was designed and established to explore the number and size of HCBs, the effects of flow rate and the addition of air cooling on the comprehensive performance of BTMS. The results indicate that a good balance of cooling performance, power consumption, and lightweight will be achieved when the number of HCBs is three, the diameter of the cooling channel on the heat exchanger block is 6 mm and the flow rate of each cooling channel is 0.002 kg/s. In this case, the maximum temperature (Tmax) is 34.41 °C and the maximum temperature difference (ΔT) is 1.53 °C. The addition of air cooling lowers Tmax and ΔT by 3.75 °C and 0.96 °C, respectively, and lowers the maximum temperature difference of single battery cell from 6.31 °C to 3.86 °C. Additionally, when intermittent air cooling is used, system power consumption is decreased while the battery pack can operate within the proper temperature range.