Battery Pack Research Articles

Heavy-duty vehicles with solar panels as a regenerative power source

Abstract Road transportation represents more than a third of all CO2-producing sources on Earth, being the main producer of greenhouse gas (GHG) emissions. Nowadays, continuous development of technology has reduced fossil-fuel consumption by integrating clean energy sources as a range extender. Solar energy has the largest potential of all renewable energy sources worldwide. The photovoltaic and energy storage research fields have grown exponentially during the last decade and, forced by the current energy crisis, had a great contribution to the hybrid solar vehicles (HSV) industry. Vehicle Integrated Photovoltaics (VIPV) comply with requirements on vehicles aesthetics, and they convert solar energy into electric energy to supply the low-voltage and high-voltage battery packs onboard HSV. Heavy-load road transportation by commercial vehicles equipped with PV-integrated modules or retrofit installation will contribute to global decarbonization. A study is done on a configuration of a heavy-duty vehicle with its cuboid cargo body covered with solar panels and a regulated driving route during different weather conditions [3]. The energy management system is designed to maximize solar energy conversion in order to reduce fuel consumption and extend the vehicle’s total driving distance.

Influences of Vibration Exposure on Battery Pack for Two-Wheeler Electric Vehicles

Influences of Vibration Exposure on Battery Pack for Two-Wheeler Electric Vehicles

Soft Short-Circuit Fault Diagnosis for Vehicular Battery Packs With Interpretable Full-Dimensional Statistical Analytics

Soft Short-Circuit Fault Diagnosis for Vehicular Battery Packs With Interpretable Full-Dimensional Statistical Analytics

Achieving Passive Thermal Runaway Propagation Resistance in Li-ion Battery Packs

Achieving Passive Thermal Runaway Propagation Resistance in Li-ion Battery Packs

An Internal Resistance Consistency Detection Approach for Lithium-Ion Battery Pack Using Unbalanced Capacitor Current

An Internal Resistance Consistency Detection Approach for Lithium-Ion Battery Pack Using Unbalanced Capacitor Current

A new method for diagnosing insulation failures in battery packs based on BiLSTM networks

A new method for diagnosing insulation failures in battery packs based on BiLSTM networks

Investigation on the thermal behavior of thermal management system for battery pack with heat pipe based on multiphysics coupling model

A well-designed battery thermal management system (BTMS) is crucial for maintaining battery life and ensuring safety in large capacity electrochemical energy storage systems. Experimental and numerical investigation have been conducted on the BTMS with heat pipe (HP) cooling. A multiphysics coupling model has been established for predicting the electrical and thermal behavior of BTMS, including HP models, electrochemical models, and computational fluid dynamics models. The model's reliability has been verified through a comprehensive set of experiments. The results show that the optimal heat dissipation effect can be achieved when the condensers of HP are distributed on both sides of the battery pack and arranged triangularly. With increasing inlet coolant velocity, the maximum temperature decreases, but the temperature uniformity deteriorates. As the inlet air temperature decreases, both the maximum temperature and the temperature uniformity decrease. The air-cooling HP-BTMS is only suitable for low discharge rates, while the liquid cooling HP-BTMS can meet the control requirements of the maximum temperature and uniformity at 3C discharge. The model has practicality in structures design and control strategies development for HP-BTMS.

Numerical and experimental investigations on thermal performance of Li-ion battery during explosion

Electric vehicles (EVs) are eco-friendly alternative to internal combustion (IC) engine based vehicles to combat with global warming. Lithium-ion batteries (LIBs) are adopted in EVs and their performance and longevity depends on thermal environment. Inadequate thermal management results in suboptimal performance, thermal runaway and consequent explosion in extreme cases. The present study delves into the experimental investigation on catastrophic failure of a Lithium ion cell under abusive conditions. The temperature variations leading up to the point of explosion were meticulously monitored, revealing a critical temperature of 440 K just before the explosion. The pressure waves during the explosion gives the sound pressure levels from 46.2 dB to 83.85 dB within a 34 ms time window and the predominant portion of sound generated during the explosion lies in the range of 129 to 3488 Hz. The battery pack discharge experiments show a temperature rises above the critical limit of 313.15 K and sudden voltage drops to the cut of value of 20 V at t = 850 s during 1C discharge condition, which shows the warning of explosion. Numerical model was developed to simulate the complex conjugate heat transfer in the cell and simulation results are validated. To underscore the practical implications, a case study of fire accident during battery cooling experiment was presented. From the insights gained by explosion of single-cell and fire accident of battery, several recommendations are provided, which includes the orientation of cells within the EVs aiming at the safety of battery design and operation.

An Ionization-Based Aerosol Sensor and Its Performance Study.

In recent years, with the rapid development of new energy vehicles, the safety issues of lithium-ion batteries have attracted attentions from all sectors of society. Research has found that during the thermal runaway process of lithium-ion batteries, aerosol emissions usually occur earlier than other gases. Accurate and timely measurement of these aerosol concentrations can help to warn the power battery pack fires. However, existing aerosol sensors are unable to meet the requirements of real-time monitoring and high precision. This article proposes an ionization mechanism based aerosol sensor that works at principles of field emission, field charging and gas discharge, and investigates its static and dynamic response characteristics. The sensor is manufactured and assembled using Microelectro Mechanical Systems processing technology. The sensor exhibits superior performances in terms of range, sensitivity, nonlinearity, repeatability, response time, and other aspects. The study provides a new solution for current aerosol detection with great potential for application.

A Resource-Constrained Polynomial Regression Approach for Voltage Measurement Compression in Electric Vehicle Battery Packs

A Resource-Constrained Polynomial Regression Approach for Voltage Measurement Compression in Electric Vehicle Battery Packs

Regenerative Braking Conscious Rule-Based Energy Management Strategy for Semi-Active Hybrid Energy Storage Systems for Electric Vehicles

Hybrid Energy Storage Systems (HESS) function as a solution to extend the lifespan of battery packs by maintaining a low charge/discharge rate. The integration of HESS in electric vehicles (EVs) is facilitated by supercapacitors (SC), known for their safe operation even under harsh conditions. The widely adopted rule-based power follower energy management strategy (EMS) is employed to control and restrict battery discharge within a defined range with SC support. Additionally, it charges the SC to accommodate regenerative energy, but it often neglects exploring the SC voltage set reference. This study investigates the SC voltage reference point and introduces a method to generate the reference point by equating the SC energy with the available kinetic energy in the moving vehicle. The proposed method was simulated and compared against the benchmark method using a portion of the medium segment Worldwide Harmonized Light Vehicles Test Procedure (WLTP) driving cycle. The results demonstrate a more stable discharge power for the battery bank, accompanied by improvements in battery voltage stability. The root mean square (RMS) battery current values were found to be 43.68 A and 42.92 A for the benchmarked and proposed methods, respectively, indicating a slight improvement of about 1%. Furthermore, the proposed method reduces the voltage deviation from 2.73% to about 2.57%, showcasing an additional positive outcome. These findings suggest that dynamically adjusting the SC voltage based on kinetic energy can enhance battery life and stability in EVs, offering a promising direction for future research and development of EMS.

Numerical simulation study on the impact of convective heat transfer on lithium battery air cooling thermal model

To enhance the accuracy of lithium battery thermal models, this study investigates the impact of temperature-dependent convective heat transfer coefficients on the battery’s air cooling and heat dissipation model, based on the sweeping in-line robs bundle method proposed by Zukauskas. By calculating and fitting the relationship between the convective heat transfer coefficient and temperature at flow rates of 0.05 m/s, 0.15 m/s, 0.25 m/s, and 0.35 m/s, it was found that the relationship is complex. An electrochemical-thermal coupling model was established using the operational characteristics of lithium batteries, and a thermal runaway reaction kinetics model was created using isothermal thermal runaway experiments and least squares optimization. The temperature-dependent convective heat transfer coefficient was then integrated into both models. Numerical simulations revealed that during normal discharge, the maximum temperature difference in the battery when the convective heat transfer coefficient is a function of temperature is less than 1 % compared to when it is constant. However, in the high-temperature thermal runaway model, the impact of temperature-dependent convective heat transfer coefficients on the thermal runaway critical parameters is minimal at flow rates of 0.05 m/s and 0.15 m/s. When the flow rate increases to 0.25 m/s and 0.35 m/s, the impact on the trigger time of thermal runaway is 17.34 % and 18.07 %, respectively. Experimental validation and research results indicate that the temperature effect on the convective heat transfer coefficient should be considered in high-temperature thermal runaway and thermal management models to calculate the convective heat transfer more accurately within the battery pack, improving model accuracy and reducing the risks of thermal runaway.

Electronically Conductive Polymer Enhanced Solid-State Polymer Electrolytes for All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems. Although solid-state ceramic (inorganic) electrolytes (SSCEs) have high ionic conductivity and high electrochemical stability, they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile), which can hinder their adoption for commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operation, which can reduce the energy density of the overall battery packages. Polymer–SSCE composite electrolytes can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In this study, we explore the feasibility of incorporating an electronically and ionically conducting polymer, polypyrrole (PPy), into a polymer backbone, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), to improve the ionic conductivity of the resultant polymer–SSCE composite electrolyte (SSPE). The electronically conductive polymer-incorporated composite electrolyte showed superior room temperature ionic conductivity and electrochemical performance compared to the baseline sample (without PPy). The PPy-incorporated polymer electrolyte demonstrated a high resilience to high temperature operation compared with the liquid-electrolyte counterpart. This performance advantage can potentially be employed in ASSLBs that operate at high temperatures. In our recent development efforts, SSPEs with optimal formulations showed room temperature ionic conductivity of 2.5 × 10−4 S/cm. The data also showed, consistently, that incorporating PPy into the polymer backbone helped boost the ionic conductivity with various SSPE formulations, consistent with the current study. Electrochemical performance of ASSLBs with the optimized SSPEs will be presented in a separate publication. The current exploratory study has shown the feasibility and benefits of the novel approach as a promising method for the research and development of next-generation solid composite electrolyte-based ASSLBs.

Distribution strategy of flexible phase change materials for pouch battery thermal management considering temperature non-uniformity

Flexible composite phase change materials (CPCMs) have been extensively studied in the thermal management of cylindrical lithium-ion batteries and proven to have a good cooling effect. However, passive cooling of pouch lithium-ion batteries with severe uneven temperature distribution has not received the attention it deserves. The thermal management of pouch battery based on passive cooling of flexible PCMs considering the heat-generating structure of pouch batteries needs to be further studied. Herein, CPCMs with different thermal conductivity were prepared, and four different distribution modes of CPCMs, including partial coverage and complete coverage, were applied to thermal management of pouch battery. Results indicated that the maximum temperature (Tmax) and maximum temperature difference (ΔTmax) can be kept separately within 35 °C and 5 °C in the passive thermal management of a single battery except upper coverage at discharge rate of 5C, and the middle coverage (case B) showed excellent temperature control in partial coverage cases. Equally noteworthy was that the increase in thermal conductivity increased the ΔTmax in partial coverage cases, while showing the opposite trend for full coverage (case ABC). Furthermore, only passive cooling of pouch battery pack did not meet the safety requirements under the discharge rate cycle of 5C. Under the active–passive combination mode, case B can control the Tmax (32.22 °C) and ΔTmax (4.69 °C) within a safe range, which was superior to case ABC (Tmax = 35.53 °C, ΔTmax = 5.04 °C). This conclusion provides technical support for the pouch battery to seek economic, stable and efficient thermal management.

Synergistic performance enhancement of lead-acid battery packs at low- and high-temperature conditions using flexible phase change material sheets

Thermal management of lead-acid batteries includes heat dissipation at high-temperature conditions (similar to other batteries) and thermal insulation at low-temperature conditions due to significant performance deterioration. To address this trader-off, this work proposes a thermal management solution based on flexible phase change materials (PCMs) with moderate thermal conductivity and other favourable properties including high specific heat capacity and high latent heat. A novel type of flexible PCM sheets is prepared with paraffin, olefin block copolymers (OBC) and expanded graphite using the co-melting method. The flexible PCM sheets are attached to a common type of lead-acid battery packs (12 Ah, dimensions of 151 × 98 × 97 mm) and thermal management performance is experimentally investigated at –10 °C and 40 °C as low- and high-temperature conditions, respectively, along with 25 °C as a baseline case for comparison purposes. Thermal properties of the battery packs such as temperature regulation and electric properties including charge/discharge capacities and rates are studied synchronously based on a standard high-performance battery detection facility. The results indicate that at –10 °C condition, the PCM sheet enhances thermal insulation of the battery pack and significantly promotes the service temperature during the charging processes. Compared with a benchmark pack attached with an encapsulated sheet, the charge and discharge capacities of the PCM-attached pack are improved by 3.7% and 5.9%, respectively. At 40 °C condition, phase transition of the PCM sheet restrains the temperature rise of the battery pack, with a maximum temperature decrease of 4.2 °C during the charging processes relative to the benchmark pack, and the temperature of the PCM-attached pack is maintained below 45 °C across 60% of the overall charge period. The overcharge and overdischarge have also been alleviated by 3.2% and 2.8%, respectively, and thus the running stability and service lifespan can be improved. The proposed PCM sheets with preferable thermal properties demonstrate potential to promote performance of lead-acid battery packs and such components are also expected to improve heat dissipation and thermal insulation in similar applications including building energy saving, thermal management of electronic chips and thermal regulation of electronic devices.

Anomaly Detection for Charging Voltage Profiles in Battery Cells in an Energy Storage Station Based on Robust Principal Component Analysis

Lithium-ion batteries, with their high energy density, long cycle life, and non-polluting advantages, are widely used in energy storage stations. Connecting lithium batteries in series to form a battery pack can achieve the required capacity and voltage. However, as the batteries are used for extended periods, some individual cells in the battery pack may experience abnormal failures, affecting the performance and safety of the battery pack. At the same time, as batteries operate in complex environments, the data collected by sensors are susceptible to random noise and drift interference, which can affect the accuracy of anomaly detection in individual battery cells. In order to solve this problem, this article proposes an anomaly detection method for battery cells based on Robust Principal Component Analysis (RPCA), taking the historical operation and maintenance data of a large-scale battery pack from an energy storage station as the research subject. Firstly, theRPCA is used to denoise the observed voltage data of the battery cells to an extreme degree, obtaining a baseline charging state curve for a cell consistency assessment. This also solves the problem of sensor outputs being affected by random noise. To further detect and identify abnormal battery cells, the RPCA is used to extract outlier components. Based on the Average Deviation-3σ principle and by utilizing Gaussian distribution probability characteristics, battery cells are conducted to screen, and the serial numbers of the anomaly cells are obtained. Finally, the effectiveness and accuracy of this anomaly detection method for battery cells are compared and verified through different statistical distributions.

Thermal–Electrical–Mechanical Coupled Finite Element Models for Battery Electric Vehicle

The safety of lithium-ion batteries is critical to the safety of battery electric vehicles (BEVs). The purpose of this work is to develop a method to predict battery thermal runaway in full electric vehicle crash simulation. The thermal–electrical–mechanical-coupled finite element analysis is used to model an individual lithium-ion battery cell, a battery module, a battery pack, and a battery electric vehicle with 24 battery modules in a live circuit connection. The lithium-ion battery is modeled using a representative approach, with each internal battery component individually modeled to represent its geometric shape and realistic thermal, mechanical, and electrical properties. A resistance heating solver and Randles circuit model built with a generalized voltage source are used to simulate the electrical behavior of the battery. The thermal simulation of the battery considers the heat capacity and thermal conductivity of different cell components, as well as heat conduction, radiation, and convection at their interfaces. The mechanical property of battery cell and battery module models is validated using spherical punch tests. The electrical property of the battery cell and battery module models is verified against CircuitLab simulation in an external short-circuit test. The simulation results for the battery module’s internal resistance are consistent with both experimental data and literature values. The multi-physics coupling phenomenon is demonstrated with a cylindrical compression simulation on the battery module. The multi-physics BEV model with 24 live battery modules is used to simulate the external short-circuit test and the side pole impact test. The simulation run time is less than 24 h. The results demonstrated the feasibility of using a representative battery model and multi-physics analysis to predict battery thermal runaway in full electric vehicle crash analysis.

PCM-based passive cooling solution for Li-ion battery pack, a theoretical and numerical study

We propose in this study a novel cooling solution for Li-ion battery packs based on Phase Change Materials (PCM) and metallic fins placed around each cell. Discharging and charging processes both melt the PCM. To complete the thermal management of the batteries, an intermediary sequence is added for the PCM solidification. During a short timeframe between batteries charging and discharging, a liquid coolant flows through one small channel located within each fin. A numerical model and a theoretical analysis allow to predict the thermal behavior of the battery cells and the PCM liquid fraction changes in time. It is shown that the combination of a passive cooling solution brought by the PCM with the fast period of liquid cooling for the PCM solidification is an effective solution to control the temperature evolution within the battery cells during discharge and charge. The only external energy consumption foreseen comes from the laminar flow of the coolant for solidification during a very short period of time. The findings indicate that the proposed PCM-liquid cooling integration reduces the total energy consumption by 54.9 % (from 0.4406 kJ to 0.1963 kJ) for the 2C discharging-2C charging cycle compared to traditional liquid-cooling strategy.

Utilizing multilayer perceptron for machine learning diagnosis in phase change material‐based thermal management systems

AbstractElectric vehicles encounter significant challenges in colder climates due to reduced battery efficiency at low temperatures and increased electricity demand for cabin heating, which impacts vehicle propulsion. This study aims to address these challenges by implementing a thermal management system utilizing Phase Change Materials (PCMs) and validating the performance of a Multilayer Perceptron (MLP) model in predicting PCMs behavior and battery temperature distributions. The study employs an MLP model trained with 160 samples of diverse heat inputs, including pulsating, constant, wiener, discharging, and random temperatures. The model uses these temperatures as inputs and liquid fractions as target values. Performance evaluation is conducted using the MATLAB platform and is benchmarked against existing approaches, such as Long Short‐term Memory (LSTM), spatiotemporal convolutional neural network (CNN), and pooled CNN‐LSTM. The MLP model's accuracy in predicting PCMs phase transitions is validated by comparing predicted liquid fractions with numerically obtained values. Additionally, this study forecasts temperature distributions within a standard battery pack under various discharge scenarios, considering the performance of commercial lithium‐ion batteries. The proposed MLP model demonstrates high efficacy, achieving a correlation of up to 0.999 and root mean squared error below 0.013 compared with numerical results.

Resources, energy consumption and economic analysis for flame synthesis of ternary cathode materials

Cathode materials account for around one third of the manufacturing cost of lithium-ion battery, which are the major factor preventing the wider applications of power battery packs. Flame synthesis (FS) is a new manufacturing technology of nanostructured materials with few equipment and high efficiency, which potentially can substantially bring down the manufacturing cost of cathode materials. The primary objective of the present study was to quantitatively evaluate the resources, energy consumption and economic feasibility of large-scale production of cathode materials though FS. In the analysis process, the mass flow of reactants and resultants as well as the minimum cathode material selling price (MCSP) of ternary cathode material LiNixCoyMn(1-x-y)O2 (x + y + z = 1) produced by FS were calculated, and compared with that of the conventional hydroxide co-precipitation method. Results show that the production of ternary cathode material through FS can reduce CO2 emissions by ∼60% and water consumption by ∼30%. MCSP of LiNi0.5Co0.2Mn0.3O2 (NCM523), LiNi0.6Co0.2Mn0.2O2 (NCM622), and LiNi0.8Co0.1Mn0.1O2 (NCM811) produced by FS are 224.8 k¥/t, 235.1 k¥/t, 240.0 k¥/t, which respectively are about 2%, 10% and 14% lower than the average selling prices in Chinese market, indicating that FS is economically feasible for producing ternary cathode materials. Particularly, for the production of high-nickel cathode materials, FS has notable potential in simplifying the production process and manufacturing costs. Sensitivity analysis of NCM811 produced by FS shows that when raw material price, fuel and power costs are reduced by 25%, MCSP can be as low as 186.4 k¥/t. When the metal cation concentration of the solution increases to 3.2 mol/L, it enables FS to meet the most rigorous energy consumption limitation standards in China. When the lithium excess is reduced from 10% to 5%, MCSP of NCM811 can be further reduced by 5.6 k¥/t, indicating that lithium loss due to high temperatures in FS is a moderate factor for reducing the manufacturing cost. Finally, this work presents a life cycle assessment (LCA) of NCM materials produced by FS in China. Comparison to the global warming potential (GWP) of the co-precipitation method in the literature indicated that GWP of FS is lower.