Cylindrical Lithium-ion Battery Research Articles

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.

Heat generation rates and anisotropic thermophysical properties of cylindrical lithium-ion battery cells with different terminal mounting configurations

This paper investigates the variation in the heat generation rates and anisotropic thermophysical properties of cylindrical 18,650 and 21,700 lithium-nickel-manganese-cobalt-oxide (NMC) battery cells when the negative terminal is mounted at different points on the cell surface. We developed a methodology that combines experimental data with a numerical inverse heat transfer (IHT) model to quantify the differences in these properties under two strategies for connecting the negative terminal to the cell surface. In the first, the negative terminal is connected at the top rim of the cell, adjacent to the positive terminal; in the second, the negative terminal is connected at the bottom of the cell, adjacent to the negative current collector. Applying this methodology, we found that the total heat generation over 1000 s for 18,650 and 21,700 cells with the negative terminal at the top rim is higher than that for batteries with the negative terminal at the bottom by up to 4.6 % and 10.7 %, respectively. The additional heat was concentrated in the cell canisters, resulting in non-uniform heat generation across the cell volume. Without considering this non-uniformity in the numerical IHT model, the characterization process yielded 15–22 % discrepancies in the predicted thermal conductivities. By considering the canister and jelly roll of the cell as separate heat generation domains, the discrepancies were reduced below 6 % and 7 % for 18,650 and 21,700 cells, respectively. This work developed an improved battery cell characterization methodology taking into account localized heat generation and extrinsic terminal mounting effects. The results underline the importance of high-fidelity cell characterization in the battery cell design process.

An investigation on thermal runaway behaviour of a cylindrical lithium-ion battery under different states of charge based on thermal tests and a three-dimensional thermal runaway model

A significant risk for lithium-ion batteries (LIBs) is fire and explosions caused by thermal runaway (TR). A TR model for LIBs with various states of charge (SOCs) can help design safer battery modules. In this work, the TR mechanism of a commercial Li[Ni5Co2Mn3]O2/graphite 18650 type cylindrical battery with various SOCs has been investigated through differential scanning calorimetry (DSC) tests on the single and mixed components. Then, a three-dimensional (3D) TR model is developed to predict the battery TR behaviours under different SOCs. This model fits well with the accelerating rate calorimetry (ARC) test results of the batteries with various SOCs. Furthermore, the validated model and ARC experiment results are employed to investigate the TR mechanism of different SOC batteries. The results show that the reaction onset temperature for cathode-anode and anode-electrolyte roughly advances as the SOC increases and the reaction enthalpy of the cathode-anode, anode-electrolyte and cathode increases with the increase of SOC. Cathode-anode, anode-electrolyte are the main heat generation in the process of battery TR, and their proportion of heat generation will decrease with the decrease of SOC.

Investigation and Optimization of Fast Cold Start of 18650 Lithium-Ion Cell by Heating Film-Based Heating Method

In this paper, based on the multi-scale multi-domain (MSMD) battery modeling approach, the NTGK model was used to model the 18650 cylindrical lithium-ion single battery on the electrochemical sub-scale. The model was successful, as it was able to fit the experimental voltage and temperature of the battery at different temperatures. Lithium-ion battery discharge capacity and energy output can be improved during cold starting by preheating and insulation, as demonstrated by a comparison of the impacts of heat transfer coefficient and preheating duration at −20 °C ambient temperature. For the traditional heating method, the heating model of heating film (HF) and liquid-cooled plate (LCP) is constructed in this paper, and the heating performance of both is compared by Fluent. Analysis of the energy balance of Li-ion battery at low temperatures has been presented, showing that Li-ion battery requires a suitable start-up temperature to maximize energy output. Taking care of the problem of excessive temperature difference inside the battery due to excessive heating power, we investigated the effects of axial thermal conductivity, heating power, and heating area on the heating uniformity of the battery in this paper. Finally, a multi-stage stepped power (MSP) heating method was proposed to improve the temperature control accuracy of HF. A level orthogonal test L16(43) without interaction was designed to determine the degree of influence of each parameter on the temperature control performance and the optimal level combination, revealing that the optimized maximum temperature and temperature control rate were reduced by 4.09% and 40.53%, respectively, when compared to direct heating.

Experimental study of liquid immersion cooling for different cylindrical lithium-ion batteries under rapid charging conditions

Experimental study of liquid immersion cooling for different cylindrical lithium-ion batteries under rapid charging conditions

Experimental and numerical investigation of a hybrid battery thermal management system based on copper foam-paraffin composite phase change material and liquid cooling

• A liquid cooling-based BTMS using CPCM was investigated under different Re , current rates and ambient temperatures. • Elevated Re of liquid cooling will increase temperature non-uniformity within the battery pack, while the temperature differences will decrease once Re further improves. • For each battery pack, parametric study needs to be carried out to reach the equilibrium between the T max , Δ T max and pump power. • Liquid cooling controls the maximum battery temperature under high ambient temperature and warms up the battery under low ambient temperature. The battery thermal management system is essential to the electric vehicle. In this paper, a battery pack consisting of 20 cylindrical lithium-ion batteries, along with the copper foam/ paraffin composite phase change material, and liquid cooling channels were set up. A numerical model was built based on the physical model, which was validated by the experimental results. The experimental and numerical test revealed elevated Reynold numbers ( Re ) will increase temperature non-uniformity within the battery pack, while the temperature differences will decrease once Re further improves. Under 0.5C discharge, the maximum temperature difference ( Δ T max ) within difference cells increased from 0.2 to 1.2 K as Re increased from 0 to 28, then it decreased to 0.4 K with Re increased to 112. The study on the current rate effect revealed that a higher current rate could lead to both higher maximum battery temperature and higher Δ T max . Under different ambient temperatures, liquid cooling is necessary as it can help with warming up the battery in a cold environment or reducing the maximum temperature in a hot environment. Compared with pure phase change material (PCM) cooling, at the end of discharge, the hybrid PCM/liquid cooling formed an 8 K temperature increase and a 13K temperature decrease under a low initial temperature of 288 K and a high initial temperature of 318 K, respectively.

Artificial neural network-based multi-objective optimization of cooling of lithium-ion batteries used in electric vehicles utilizing pulsating coolant flow

Due to the enhancement of production and development of electric vehicles, their improved performance has attracted much attention. Lithium-ion battery packs that supply the energy needed for electric vehicles require cooling to enhance their function, reduce costs and increase lifetime. The current work investigates the effect of using pulsating flow instead of steady flow on batteries' maximum temperature and temperature difference. In this respect, two different arrangements have been utilized with a commonly used cylindrical lithium-ion battery named 18650. The results demonstrate that pulsating flow decreases the maximum temperature and maximum temperature difference by 27% and 50%, respectively, in an optimal setting. The influence of three main characteristics of pulsating flow on the battery pack cooling system has been studied. These characteristics are the Strouhal number and the oscillation amplitude, while the Reynolds number is taken as a parameter. In both arrangements, by increasing the amplitude, maximum temperature and maximum temperature difference are reduced. As expected, increasing the Reynolds number would improve cooling performance. The effect of the Strouhal number on the maximum temperature and maximum temperature difference indicates the existence of extremum points in both arrangements. Moreover, the optimum points in both battery packs are different, which means the optimum point depends on the geometry. A double-objective optimization was carried out using a surrogate model obtained by artificial intelligence to find the Pareto front for minimizing both the maximum temperature and the maximum temperature difference. Moreover, for the best points on the Pareto front, the optimal Strouhal number in the staggered and in-line arrangement of batteries are 0.5457 and 0.369, respectively.

Thermal performance of honeycomb-type cylindrical lithium-ion battery pack with air distribution plate and bionic heat sinks

• •Air distribution plate with bionic channel is designed in the honeycomb-type battery pack. • •Temperature difference of battery module with air distribution plate is reduced by 7.0 K. • •Installing bionic heat sinks enhance the temperature uniformity of the battery module. • • An estimation method is proposed to analyze the temperature range of the battery pack. In this paper, the thermal performance of air-cooled battery thermal management (BTM) for honeycomb-type cylindrical lithium-ion battery pack is studied. The battery pack consists of twenty-four hexagonal battery modules, and the pipe network in battery pack transports cooling air to each battery module. Then, an air distribution plate (ADP) is designed for the battery module to improve temperature consistency, and the cooling performance and velocity distribution are studied numerically with computational fluid dynamics (CFD). As compared with the normal battery module without ADP at inlet velocity of 12 m/s and discharge rate of 3 C, the maximum temperature and temperature difference of ADP battery module are reduced by 1.7 K and 7.0 K, respectively. Meanwhile, improving the structure of the ADP and installing some bionic heat sinks in the spaces of batteries can maintain the temperature difference of the battery module within 2 K. In addition, an estimation method is proposed to analyze the temperature range of the battery pack, which uses a simplified model to simulate the relationship between the inlet velocity and pressure drop of battery module. The estimation results show that the temperature difference of battery pack with optimal design of pipe arrangement can be controlled to 2.5 K.

Thermal reliability assessment and sensitivity analysis of 18,650 cylindrical lithium-ion battery

In order to solve the problems of thermal safety and thermal reliability of the battery, a method of thermal reliability assessment and reliability sensitivity analysis for an 18,650 cylindrical lithium-ion battery is proposed. The finite element analysis (FEA) software is used to establish an electrochemical-thermal coupling model of the lithium-ion battery. By comparing the expected and experimental results, the accuracy of the proposed model is verified, and the model is subsequently used to analyze the thermal reliability. The adaptive Kriging method is used to establish the thermal reliability performance function model and assess the thermal reliability of the lithium-ion battery. Additionally, in order to study the influence of the material parameters on the thermal reliability of the battery, gradual reliability and reliability sensitivity analyses are conducted. The results show that when the density is 3150 kg/m3, the reliability reaches 0.993, which is 14.4 % higher than that of the existing battery, while the sensitivity value decreases. When the specific heat capacity is 1310 J/kg·K, the reliability of the battery reaches 0.986, which is 13.6 % higher than that of the existing battery, while the sensitivity value decreases. Lastly, the thermal conductivity has little influence on the thermal reliability of the battery.

Influence of Breathing and Swelling on the Jelly-Roll Case Gap of Cylindrical Lithium-Ion Battery Cells

Cylindrical 18650 and 21700 lithium-ion batteries are produced with small gaps between the jelly roll and the case. The size of these gaps and the mechanical attachment of the jelly roll to the case can have a significant impact on the thermal and mechanical properties of cells. To investigate the influence of the state of charge (SOC) and state of health (SOH) on the size of the gap, computed tomography (CT) and gray-value analysis was conducted with various cell types at 0% and 100% SOC and after cycling. The results show a significant influence of the SOC on the gap for new cells and a substantial reduction in the gap during the first cycles.

Multi-objective optimization of an air cooling battery thermal management system considering battery degradation and parasitic power loss

The battery thermal management system (BTMS) can effectively ensure that the batteries work in a safe temperature range and solve the problems caused by high temperature. This paper investigates an air cooling BTMS with 32 cylindrical lithium-ion batteries (LIBs). Previous BTMS studies pay little attention to cost, this work focuses on the economic cost to address the cost problem caused by the parasitic power consumption of BTMS. First, the battery degradation model is established, and the cycle life of the battery is determined through capacity loss. Second, the computational fluid dynamics (CFD) simulation is used to study the influence of design parameters on the maximum temperature (MT) of the battery module and the pressure drop. Then, this study proposes to use cyclical cost (including battery cycle life and parasitic power loss) to evaluate the economy. The MT and cyclical cost are simultaneously considered as the optimization objectives to form an optimization model via the surrogate model method. Finally, two multi-objective optimization algorithms are used to drive the optimization process. The results suggest that the MT drops from 314.58 K to 314.22 K, while the cyclical cost drops from 0.92 €/cycle to 0.85 €/cycle, a reduction of 7.6 %. The developed method could improve the economy while ensuring the heat dissipation performance of the battery, which provides guidance for the design of BTMS to meet the needs of consumers.

Thermal Investigation of Cylindrical Lithium-ion Batteries for Different Loading using Experimental and Numerical Techniques

With growing concerns over climate change due to automotive emissions and fossil fuel depletion, electric vehicles (EVs) have gained more interest as a mode of transportation. Mostly, lithium-ion batteries are being used as an energy storage system in EVs. Temperature plays a major role in lithium-ion battery performance, degradation, and safety. Thermal investigation of cylindrical lithium-ion batteries of different chemistry and shape factors (18650 NMC and 21700 NCA) is conducted for different charging/discharging rates (0.5 C, 1 C, 1.5 C) and surrounding temperatures (26 °C and 45 °C) using numerical and experimental techniques. The numerical technique involves the determination of the surface temperature of the battery by solving the energy balance equation using a suitable numerical method. The numerical technique proposed in this study is validated using the experimental technique and can predict the temperature with at least 90% accuracy during the entire charging and discharging cycle from a lower to higher loading rate and different surrounding temperatures. The impact of different battery internal and external parameters on battery temperature is carried out using validated numerical technique. Thermal investigation conducted in this research can help in deciding the operating strategies of the battery management system and further in designing the proper thermal management system.

Numerical Simulation of the Combination of Novel Spiral Fin and Phase Change Material for Cylindrical Lithium-Ion Batteries in Passive Thermal Management

This paper uses ANSYS Fluent to simulate the heat dissipation of a phase change material (PCM)-based cooling system combined with novel spiral fins for a single battery cell. Compared with a circular fin, a spiral fin with the same contact length can reduce the battery temperature by 0.72 °C, and has a superior temperature uniformity. For the PCM-based system with spiral fins, increasing the spiral width from 2 mm to 8 mm can reduce the battery temperature from 41.27 °C to 39.9 °C. As the number of spiral turns increases from two to eight, the maximum temperature rise of the battery shows a downward trend, and six turns can effectively satisfy the heat dissipation requirements of the battery. With respect to the effect of ambient temperature on the cooling performance, the system with a PCM-spiral fin still exhibits optimal cooling effectiveness compared with the pure PCM and PCM-circular systems.

Stress and Displacement of Cylindrical Lithium-Ion Power Battery during Charging and Discharging

During the charging and discharging process of a lithium-ion power battery, the intercalation and deintercalation of lithium-ion can cause volume change in the jellyroll and internal stress change in batteries as well, which may lead to battery failures and safety issues. A mathematical model based on a plane strain hypothesis was established to predict stresses in both the radial and hoop directions, with the hoop stress of each winding layer of the jellyroll obtained. Displacements of the steel case, the jellyroll, and the core of the battery during the charging and discharging processes were also analyzed, with the effect of lithium-ion concentration and the battery size discussed. The research results can explain well the wrinkling and fracture of the jellyroll.

Impact of Current Collector Design and Cooling Topology on Fast Charging of Cylindrical Lithium-Ion Batteries

The 18 650 and 21 700 cell format are state of the art for high-energy cylindrical lithium-ion batteries, while Tesla proposed the new 4680 format with a continuous ”tabless” design as the choice for electric vehicle applications. Using an experimentally validated multidimensional multiphysics model describing a high energy NMC811/Si-C cylindrical lithium-ion battery, the effects of tabless design and cooling topologies are evaluated for 18 650, 21 700, and 4680 cell formats under varying charging protocols. Mantle cooling is found to be the most efficient cooling topology for a segmented tab design, whereas tab cooling performs equally well for tabless cells and achieves better performance for the 4680 format. By massively reducing polarization drops (approx. 250 mV at 3C) and heat generation inside the current collectors (up to 99%), the tabless design increases cell homogeneity and enables format-independent scalability of fast-charging performance with a tab-cooling topology. In addition, the 0 to 0.8 SoC charge time can be reduced by 4 to 10 min compared to cells with a segmented tab design, resulting in 16.2 min for the 18 650 and 21 700, and 16.5 min for the larger 4680 cell format.

Cooling performance and optimization of a new hybrid thermal management system of cylindrical battery

To enhance the temperature uniformity of liquid cooling system, an effective strategy was proposed based on liquid cooling and micro heat pipe array (MHPA) for prismatic batteries. But whether this hybrid battery thermal management system (BTMS) still works effectively for cylindrical lithium-ion batteries needs to be verified and its optimal design has not been worked due to complex factors and paraments of hybrid BTMS. In this paper, a novel hybrid BTMS for the cylindrical batteries is proposed based on MHPA and liquid cooling, whose cooling performance is investigated experimentally and numerically. The result shows that compared with the module without MHPA, the maximum temperature of the hybrid module is reduced by 34.11 % and the temperature difference is decreased from 3.66 °C to 0.66 °C, in 1C discharging progress. Even in 3C, the maximum temperature and temperature difference decreased to 41.03 °C and 2.16 °C, respectively. To optimize the energy density and cooling performance, multi-objective optimization is applied based on the Non-dominated Sorting Genetic Algorithm Ⅱ (NSGA-Ⅱ) coupled with the Response Surface Methodology (RSM). According to the Pareto-optimal solution, the energy density of the optimized BTMS can increase 13.75 % to 122.39 Wh/kg with the cooling performance changed lightly, compared with the original module.

Effect of Thermal Abuse Conditions on Thermal Runaway of NCA 18650 Cylindrical Lithium-Ion Battery

In energy storage systems and electric vehicles utilizing lithium-ion batteries, an internal short circuit or a thermal runaway (TR) may result in fire-related accidents. Particularly, under non-oxygenated conditions, a fire can spread as a result of TR. In this study, a TR experiment was performed on a nickel–cobalt–aluminum 18650 cylindrical lithium-ion battery via thermal conduction. The time required to attain TR (temperature range: 250–500 °C) was drastically reduced from approximately 1200 s to 1 s. The chemical reaction rate of thermal runaway was classified according to temperature into two global mechanisms and applied to the Arrhenius equation, thereby yielding a correlation between plate temperature (TP) and time difference of TR times ∆t (i.e., t1−t0 or t2−t0). As a result, activation energy for the overall reaction of the TR was estimated to be 39.9 kJ/mol. Furthermore, the safety guarantee time mandated by the safety regulation for vehicle batteries is 5 min; an analysis of the experiment results reveals that the following conditions can be satisfied: TP = 308.4 °C, Δtt1−t0 = 5 min; TP = 326.2 °C, Δtt2−t0 = 5 min. The experiment results offer a scientific basis for predicting the time of occurrence of TR and establishing safety standards.