Lithium-ion Batteries In Electric Vehicles Research Articles

A simulation-driven prediction model for state of charge estimation of electric vehicle lithium battery

Accurately predicting the state of charge (SOC) of lithium-ion batteries in electric vehicles is crucial for ensuring their stable operation. However, the component values related to SOC in the circuit typically require estimation through parameter identification. This paper proposes a three-stage method for estimating the SOC of lithium batteries in electric vehicles. Firstly, the parameters of the constructed second-order RC circuit are identified using the Forgetting Factor Recursive Least Squares (FFRLS) method. Secondly, an innovative approach is employed to construct a battery simulation model using modal-data fusion method. Finally, the predicted values of the simulation model are corrected using the unscented Kalman filter (UKF). Validation through datasets demonstrates the high precision of this method in parameter identification. Moreover, in the comparison of SOC prediction corrections with Particle Filter (PF), Extended Kalman Filter (EKF), and the proposed UKF on simulated prediction data and experimental test data. The proposed method achieves the lowest root mean square error (RMSE) of 0.0025 for simulation prediction data and 0.0186 for experimental test data. It also maintained its error within 5 % on actual data.

Hydrogen Reduction Behavior of NCM-based Lithium-ion Battery Cathode Materials

As the demand for lithium-ion batteries for electric vehicles is increasing, it is important to recover valuable metals from waste lithium-ion batteries. In this study, the effects of gas flow rate and hydrogen partial pressure on hydrogen reduction of NCM-based lithium-ion battery cathode materials were investigated. As the gas flow rate and hydrogen partial pressure increased, the weight loss rate increased significantly from the beginning of the reaction due to the reduction of NiO and CoO by hydrogen. At 700 °C and hydrogen partial pressure above 0.5 atm, Ni and Li2O were produced by hydrogen reduction. From the reduction product and Li recovery rate, the hydrogen reduction of NCM-based cathode materials was significantly affected by hydrogen partial pressure. The Li compounds recovered from the solution after water leaching of the reduction products were LiOH, LiOH·H2O, and Li2CO3, with about 0.02 wt% Al as an impurity.

Dual-gate design enables intrinsic safety of high-energy batteries

The safety issue hampers the application of high-energy lithium-ion batteries in electric vehicles, grid energy storage, electric ships and aircrafts. The chemical cross-talk, which refers to the migration of energetic intermediates between cathode and anode, initiates battery self-heating and accelerates the intensive heat release during battery thermal failure. However, blocking the chemical cross-talk is extremely hard. Previously, we may expect a thermally stable separator can guard the gate between battery cathode and anode, however, large amount of hot gas breaks the defense mechanically not thermally. Draining the cross-talk gas is of equal importance with blocking it. Herein, a dual-gate design notion is proposed, using separator as “block gate” and vent valve as “removal gate” to regulate the spatial distribution of energetic species to reduce the major heat release during battery thermal runaway. The design is validated by more than 50 battery chemistries. Typically, the maximum temperature of NMC811||Gr pouch cell decreases from >800 °C to <300 °C, the highest temperature rising rate decreases from 761.0 °C/s to 0.013 °C/s. The morphology and crystalline change of cathode verify that the chemical cross-talk is successfully suppressed. Moreover, such design has little side effect on the electrochemical performance of batteries. The dual-gate design breaks the bottleneck for the safety design of high energy batteries, providing insight into the safe utilization of electrochemical energy storage materials.

The suppression of thermal propagation using spray cooling with R410A in overheated lithium battery pack

Currently, the thermal safety control of lithium-ion batteries for electric vehicles has emerged as a prominent research focus in both academia and industry. During the transition from overheating to the initial stage of thermal runaway, lithium batteries undergo an overheating decomposition reaction, which presents an opportunity for proactive prevention of thermal runaway. In this context, this study proposes a spray cooling method and performs numerical simulations to investigate the impact of spray cooling on suppressing overheating propagation in battery packs. Specifically, we examine the suppressor effect of spray cooling on propagating overheating within the battery pack. The cooling effect of R410A spray was investigated at three typical positions prone to overheating. We analyzed changes in thermal behavior characteristics of individual batteries within the pack and evaluated its inhibitory effect on propagating of overheating. The spray strategy is also improved and optimized by increasing the number of spray nozzles and spraying in advance. The results demonstrate that the implementation of the spray cooling method in this study effectively mitigates the average temperature of the overheated battery, thereby preventing the overheating decomposition reaction. Simultaneously, the spray cooling effectively suppresses the heat propagation of excessively heated batteries within the battery pack, thereby preventing and delaying the onset of thermal runaway in the battery pack.

Enhanced thermal management of electric vehicle lithium-ion batteries with Al2O3–MWCNT–ethylene glycol hybrid nanofluid-based helical coiled pulsating heat pipe (HC-PHP)

Enhanced thermal management of electric vehicle lithium-ion batteries with Al2O3–MWCNT–ethylene glycol hybrid nanofluid-based helical coiled pulsating heat pipe (HC-PHP)

Service life estimation of electric vehicle lithium-ion battery pack using arrhenius mathematical model

Durability is a desired characteristic for all battery packs in Electric Vehicles. In this study, the service life of the EV battery pack under real-world operating conditions is projected using an Arrhenius mathematical simulation model. The model comprises a 39.2 kWh EV Lithium-Ion battery pack integrated with a three-phase inverter to convert the battery pack’s Direct Current output to Alternating Current. In addition, the Alternating Current output is coupled to a 100 kW permanent magnet synchronous motor, which is regarded as the load. A field-oriented controller provides pulse width-modulated output signals that are supplied back to the inverter to generate the correct driving current. Variable conditions of charge rate (C-rate: 1.25C − 4C), discharge rate (C-rate: 0.5C − 4C), temperature (25°C–60°C), and depth of discharge (30%–90%) are evaluated to determine the battery pack’s service life. Under a 4C charge rate/0.5C discharge rate and 50% depth of discharge, the modeling results indicate the battery pack has a service life of approximately 6,000 h at low temperatures (25°C) and roughly 3,000 h at high temperatures (60°C). The model has been validated by comparing the results with experimental data from the literature.

Robotic Disassembly Platform for Disassembly of a Plug-In Hybrid Electric Vehicle Battery: A Case Study

Efficient processing of end-of-life lithium-ion batteries in electric vehicles is an important and pressing challenge in a circular economy. Regardless of whether the processing strategy is recycling, repurposing, or remanufacturing, the first processing step will usually involve disassembly. As battery disassembly is a dangerous task, efforts have been made to robotise it. In this paper, a robotic disassembly platform using four industrial robots is proposed to automate the non-destructive disassembly of a plug-in hybrid electric vehicle battery pack into modules. This work was conducted as a case study to demonstrate the concept of the autonomous disassembly of an electric vehicle battery pack. A two-step object localisation method based on visual information is used to overcome positional uncertainties from different sources and is validated by experiments. Also, the unscrewing system is highlighted, and its functions, such as handling untightened fasteners, loosening jammed screws, and changing the nutrunner adapters with square drives, are detailed. Furthermore, the time required for each operation is compared with that taken by human operators. Finally, the limitations of the platform are reported, and future research directions are suggested.

전기자동차 배터리 냉각 플레이트의 유동 형상에 따른 냉각 성능에 관한 연구

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

Electrochemical 3-D morphology based degradation quantification framework for lithium-ion battery under low temperature

In high-latitude areas, lithium-ion batteries for electric vehicles frequently operate under low-temperature conditions. However, lithium-ion battery suffers from complex energy loss and performance degradation under low temperature. In order to quantify the degradation mode of the battery, this paper proposes a framework with electrochemical theory and electrode 3-D morphology. The proposed framework mainly includes two parts: Firstly, the degradation modes (DMs) of the battery are extracted from incremental capacity (IC), differential voltage (DV) techniques and electrochemical impedance spectroscopy (EIS). Secondly, the 3-dimension (3-D) morphological calculation method is proposed to analyze the degradation situation of the battery electrodes. Then, the battery aging and performance testing system under low temperature is established to verify the effectiveness of the proposed framework from the perspective of surface morphology. In order to validate the effectiveness of the proposed framework, an experimental bench for battery low-temperature aging and performance testing is constructed. The experimental results demonstrate that: (1) Battery capacity is greatly reduced at low temperatures, and loss of lithium inventory (LLI) is greater at low temperatures (−5 °C and −10 °C) than at 25 °C under the same state of health (SOH). (2) By analyzing 3-D morphology, the low temperature can lead to a significant change in the surface roughness parameters of the anode electrode. The low temperature aggravates the reduction of anode gap area. It is found that the microscopic mesomorphic changes are closely related to the aging of the battery. (3) The anode graphite (002) peak position is shifted to a low angle of 2.2° under low temperature. Scanning electron microscope (SEM) images shows the graphite anode is covered by a lithium-rich SEI at low temperature. (4) Post-test calculations of the consistency of the relevant covariates revealed that the electrochemical and morphological covariates are highly linearly correlated, respectively. Hence, the effectiveness of the proposed framework is verified and a novel perspective is provided to reveal the battery performance degradation under low temperatures, which can help guarantee safe operation through battery management system.

A review of integrated battery thermal management systems for lithium-ion batteries of electric vehicles

Lithium-ion batteries have emerged as a promising choice for electric vehicle applications. However, thermal runaway and related catastrophic issues perplex the research community when batteries are subjected to varying charging/discharging and different ambient temperatures. In order to keep the batteries under a safe zone of temperature, battery thermal management occupies utmost importance and hence researchers are switching over to a combination of either two or three strategies since single stragaty could not meet effective thermal management. In a combined strategy, the use of phase change materials and is highly essential due to their inherent thermo-physical properties; both organic and inorganic types have been explored. To enhance the heat dissipation, the phase change materials, regarded as composite phase materials, are being added with graphite powder, nanomaterials, metal foams, and fins are being arranged to the battery cells. The present review enumerates the recent progress made in achieving good thermal performance with hybrid/integrated battery thermal systems with an emphasis on the use of composite phase change materials. The review revealed that the hybrid strategy is performing well, machine learning and advanced optimization methods are being applied to understand the state of health of batteries. Few works are focussed on the mitigation of thermal runaway propagation serving the composite phase change materials as effective flame retardants. The current status and challenges being faced in the use of LIBs is also briefed. It is essential to develop economical integrated battery thermal management systems with parasitic power losses that are compact and safe to attract many city dwellers to adopt pure electric vehicles besides meeting the mandate of sustainable development goals. The review is an attempt to provide a ready reckoner in the area of integrated battery thermal management involving composite phase materials.

Multi-objective nonlinear observer design for multi-fault detection of lithium-ion battery in electric vehicles

Accurate and rapid fault detection is essential for the safe operation of lithium-ion batteries in electric vehicles. However, conventional fault detection methods dependent on constant thresholds may have false alarms or missing alarms due to the inevitable disturbances resulted from the battery system modeling errors and measurement noises. In this paper, we design a multi-objective nonlinear fault detection observer for lithium-ion batteries, which is robust against disturbances but sensitive to battery multi-fault. We then perform formal stability and L∞/H_ performance analysis for the resultant estimation error system. Furthermore, tractable design procedures for the observer gain parameter and an adaptive threshold are derived. Then, via adaptive thresholding, a delicate three-step multi-fault detection scheme is developed to detect the occurrence of battery various faults, including short-circuit faults, current and voltage sensor faults. Finally, the efficacy of the proposed scheme is validated under several experimental case studies involving a variety of faults with their different levels of severity and erroneous SOC initialization.

Circularity scoring system: A product specific application to lithium-ion batteries of electric vehicles

The transition towards electric mobility has gained significant momentum in recent years, raising concerns on the environmental and social implications of lithium-ion batteries. Specifically, there are ongoing challenges related to the future supply of critical raw materials and the sustainable management of used batteries with remaining capacity. To address this, a 'Circularity Scoring System' is proposed. The method aims to evaluate specific aspects of the battery design and the manufacturer's support infrastructure that currently hamper the implementation of circular economy strategies. A comprehensive list of 25 evaluation criteria was initially compiled from existing standards on material efficiency. Then, 9 criteria were ultimately selected, weighted, and defined to evaluate a battery's potential to undergo three distinct pathways: repair and reuse, remanufacturing and repurpose, or recycling. Through this method, a final score is generated for each circular strategy, providing valuable insights for continually enhancing battery design and, subsequently, their sustainability.

Effects of intermittent pulsating flow on the performance of multi-channel cold plate in electric vehicle lithium-ion battery pack

In order to address the thermal management of electric vehicle lithium-ion battery pack, the intermittent pulsating flow is proposed to apply in the multi-channel cold plate of electric vehicle lithium-ion battery pack. Extensive numerical investigations on the maximum temperature (Tb,max) and maximum temperature difference (ΔTb,max) and of the lithium-ion battery pack, transfer coefficient (h), pressure loss (Δp), efficiency index (EI), pump power (Ppump), and energy consumption (W) of the multi-channel cold plate under intermittent pulsating flow and pulsating flow are conducted. Results show that Tb,max and ΔTb,max under intermittent pulsating flow is lower than those under pulsating flow at the first half of the whole discharging process, which suggests that the intermittent pulsating flow can make the lithium-ion battery pack achieve better temperature characteristics. However, W of cold plate under intermittent pulsating flow is much higher than that under pulsating flow at the same pulsation amplitude and frequency. It is always increased at the fixed pulsation frequency with the increase of pulsation amplitude and reaches the minimum value at the pulsation frequency of 3 Hz when the pulsation amplitude is fixed.

Multiplex Characteristics and Vulnerability Assessment of the Global Electric Vehicle Lithium-Ion Battery Supply Chain Network: A Focal Firm-Specific Analysis

Multiplex Characteristics and Vulnerability Assessment of the Global Electric Vehicle Lithium-Ion Battery Supply Chain Network: A Focal Firm-Specific Analysis

Life cycle assessment of secondary use and physical recycling of lithium-ion batteries retired from electric vehicles in China

With the rapid development of the global new energy vehicle industry, how to minimize the environmental impact of the recovery has become a common concern and urgent concern. China is a major production and consumption market for electric vehicles, there are no specific and extensive resource and environmental assessment system for batteries. In this paper, the retired Electric vehicles lithium-ion batteries (LIBs) was the research object, and a specific analysis of the recycling treatment and gradual use stages of power batteries were based on life cycle assessment. Different battery assessment scenarios were established according to the development of battery recycling in China. The results showed that the secondary use has the optimal performance compared to the full-component physical, pyrometallurgical and hydrometallurgy recycling. The results showed that direct recycling has a GWP of 0.037 kg-CO2 eq·kg LIB-1, which is lower than others. Secondary use of LIB accounts for the most emission reductions with Global warming (GWP) as 12.134 kg-CO2 eq·kg LIB-1. The secondary use has the greatest impact on the assessment results, especially in dynamic scenarios. Through a comprehensive comparison of different recycling technologies, the secondary use, increasing the recycling rate, reducing resource, energy consumption and pollution emissions.

Research on control strategy of rapid preheating for power battery in electric vehicle at low temperatures

Due to cold weather conditions, it is not advisable to use the remaining capacity of the power battery to heat it. Instead, the battery can only be preheated during charging when the battery power is almost consumed up. The traditional positive temperature coefficient (PTC) heating system combines the cockpit air conditioning and heating system with the low-temperature preheating system for the power battery cells. The PTC controller is integrated into the air conditioning control system. However, this integration requires the air conditioning to be activated in order to preheat the power battery. As a result, there is energy waste during the charging process. To address the aforementioned issues, this article proposes a rapid preheating system that utilizes an independent liquid circuit equipped with a high-voltage heater. The system achieves a preheating time of 2000 s for a ternary lithium battery with a capacity of 73kWh and a rated voltage of 770 V. Another important finding is that fluctuations in the current of the battery management system (BMS) occur during the rapid preheating process, leading to uncontrolled battery charging and discharging. The battery rapid preheating control strategy has been redesigned to rapidly heat the battery system by disconnecting the rapid charging relay of the high-voltage circuit, thereby prevents over-discharge and overcharge of the power battery. Experiments have shown that the BMS current increases or decreases in a stepwise manner, as expected by the design. The average temperature of the battery pack during onboard charge module slow charging and direct current fast charging is below 35 °C, and the maximum temperature difference is less than 6 °C. The proposed rapid preheating system and improved battery charging architecture can shorten the charging time and reduce energy consumption. This advancement will open up new possibilities for power battery protection and contribute to the development of lithium-ion batteries for electric vehicles at low temperatures.

An Intelligent Charging Scheme for Lithium-Ion Batteries of Electric Vehicles Considering Internal Attenuation Modes

Charging control is one of the essential functions of battery management systems. Battery charging involves behavioral changes such as electricity, heat, and aging. Balancing these factors is crucial for the safe and efficient operation of batteries. This work proposes an intelligent charging scheme for lithium-ion batteries that considers charging time, temperature rise, and health losses. Firstly, charging aging experiments are conducted to investigate the effect of charging rate on battery aging. Specifically, half cell experiments are carried out to construct an electrode open circuit voltage model to explore battery aging modes. The aging mode attenuation model is proposed based on empirical formulas. Then, the charging multi-objective function is established based on the equivalent circuit, thermal, and aging empirical models. A multi-stage constant current charging optimization scheme has been developed based on the multi-objective grey wolf optimizer. Finally, the feasibility of three targets and dual targets fast charging schemes is verified through simulation and experiments.

Polyplastics’ introduces new heat resistant DURAFIDEⓇ PPS grade for EV

Polyplastics Group, a global supplier of engineering thermoplastics, has announced DURAFIDEⓇ PPS 6150T73, a high-performance material which reportedly delivers outstanding heat resistance and exceptional thermal and electric insulation properties, for electric vehicle (EV) lithium-ion (Li-ion) batteries.

Heat dissipation performance research of battery modules based on composite phase change materials cooling and electrochemical thermal coupling model

In order to improve electric vehicle lithium-ion batteries (LIBs) performance and increase cycle life, it is crucial to design a reliable and efficient battery thermal management system (BTMS). Compared with other active battery cooling methods, passive phase change material (PCM) cooling has the advantages of simple structure, good temperature control uniformity, strong reliability, and no additional energy consumption. This article uses a series of experimental procedures to add expanded graphite to traditional paraffin wax PCM and obtain composite phase change materials (CPCM) with different mixing ratios. A control experiment is created to compare the cooling performance of the CPCM cooling with natural convection cooling, research shows that the cooling performance of CPCM can well meet the cooling demand which maximum temperature and maximum temperature difference of battery modules. In addition, to study the performance of thermal properties parameters related to CPCM, a COMSOL numerical calculation model of battery module based on CPCM cooling and electrochemical thermal coupling model is established. The effectiveness and accuracy of the model are verified through heat generation experiments at different rates (0.5 C, 1 C, 1.5 C), with a maximum temperature error of 1.6 K and an error accuracy of less than 0.6%. Subsequently, the performance of phase change temperature, thermal conductivity and phase change latent heat is studied and reasonable value ranges are obtained, which are 312 K∼318 K, 2.5 W /(m·K), and 175 J/g∼200 J/g, respectively.

Thermal Performance Enhancement of Lithium-Ion Batteries Using Phase Change Material and Fin Geometry Modification

The rapid increase in emissions and the depletion of fossil fuels have led to a rapid rise in the electric vehicle (EV) industry. Electric vehicles predominantly rely on lithium-ion batteries (LIBs) to power their electric motors. However, the charging and discharging processes of LIB packs generate heat, resulting in a significant decline in the battery performance of EVs. Consequently, there is a pressing need for effective battery thermal management systems (BTMSs) for lithium-ion batteries in EVs. In the current study, a novel experimental BTMS was developed for the thermal performance enhancement of an LIB pack comprising 2 × 2 cells. Three distinct fin configurations (circular, rectangular, and tapered) were integrated for the outer wall of the lithium-ion cells. Additionally, the cells were fully submerged in phase change material (PCM). The study considered 1C, 2C, and 3C cell discharge rates, affiliated with their corresponding volumetric heat generation rates. The combination of rectangular fins and PCM manifested superior performance, reducing the mean cell temperature by 29.71% and 28.36% compared to unfinned lithium-ion cells under ambient conditions at the 1C and 2C discharge rates. Furthermore, at the 3C discharge rate, lithium-ion cells equipped with rectangular fins demonstrated a delay of 40 min in reaching the maximum surface temperature of 40 °C compared to the unfinned ambient case. After 60 min of battery discharge at the 3C rate, the cell surface temperature of the rectangular fin case only reached 42.7 °C. Furthermore, numerical simulations showed that the Nusselt numbers for lithium-ion cells with rectangular fins improved by 9.72% compared to unfinned configurations at the 3C discharge rate.