Lithium-ion Phosphate Research Articles

Application of cathode materials in lithium ion phosphate battery and its modification

Abstract Lithium ion batteries have been widely used in various fields, such as electric vehicles, due to their excellent electrochemical performance. Especially, introducing some functional materials into batteries can further improve battery performance. This research analyses the application of lithium-ion phosphate as the cathode materials of the batteries, with a particular focus on the structural characteristics and various indices of the modification of lithium iron phosphate battery cathode materials. The electrode material is systematically described, highlighting its advantages, disadvantages, and application range while emphasizing its crucial role in different electrochemical performance such as energy density and recyclability. In addition, the relationship between the electrochemical performance and structure properties of cathode materials in LiFePO4 is summarized by placing emphasis on nanoparticle characteristics, interface environment effects, and electrode structures. This research also presents a series of achievements in modifying lithium iron phosphate cathode materials. And it identifies areas that require improvement and looks forward to future challenges and developments in lithium-ion battery cathode materials.

Design and implementation of a high misalignment-tolerance wireless charger for an electric vehicle with control of the constant current/voltage charging

Wireless charging of Electric Vehicles (EVs) has been extensively researched in the realm of electric cars, offering a convenient method. Nonetheless, there has been a scarcity of experiments conducted on low-power electric vehicles. To establish a wireless power transfer system for an electric vehicle, optimal power and transmission efficiency necessitate arranging the coils coaxially. In wireless charging systems, coils often experience angular and lateral misalignments. In this paper, a new alignment strategy is introduced to tackle the misalignment problem between the transmitter and receiver coils in the wireless charging of Electric Vehicles (EVs). The study involves the design and analysis of a coil, considering factors such as mutual inductance and efficiency. Wireless coils with angular misalignment are modelled in Ansys Maxwell simulation software. The proposed practical EV system aims to align the coils using angular motion, effectively reducing misalignment during the parking of two-wheelers. This is achieved by tilting the transmitter coil in the desired direction. Furthermore, micro sensing coils are employed to identify misalignment and facilitate automatic alignment. Additionally, adopting a power control technique becomes essential to achieve both constant current (CC) and constant voltage (CV) modes during battery charging. Integrating CC and CV modes is crucial for efficiently charging lithium-ion batteries, ensuring prolonged lifespan and optimal capacity utilization. The developed system can improve the efficiency of the wireless charging system to 90.3% with a 24 V, 16 Ah Lithium Ion Phosphate (LiFePO4) battery at a 160 mm distance between the coils.

STUDY OF LITHIUM ION CHARGING AND DISCHARGING CHARACTERISTICS

Lithium –Ion batteries are now popular in majority of electronic portable devices like Mobile phone, Laptop, Digital Camera, etc. due to their long lasting power efficiency. These are the most popular rechargeable batteries with advantages like best energy density, negligible charge loss and no memory effect. Li-Ion battery uses Lithium ions as the charge carriers which move from the negative electrode to the positive electrode during discharge and back when charging. During charging, the external current from the charger applies an over voltage than that in the battery. This forces the current to pass in the reverse direction from the positive to the negative electrode where the lithium ions get embedded in the porous electrode material through a process called Intercalation. The Li- Ions pass through the non-aqueous electrolyte and a separator diaphragm. The electrode material is intercalated lithium compound. The negative electrode of the Li-Ion battery is made up of carbon and the positive electrode is a metal oxide. The most commonly used material in the negative electrode is Graphite while that in the positive electrode may be Lithium cobalt oxide, Lithium ion phosphate or Lithium manganese oxide. Lithium salt in an organic solvent is used as the electrolyte. The electrolyte is typically a mixture of organic carbonates like Ethylene carbonate or Diethyl carbonate containing lithium ions. The electrolyte uses anion salts like Lithium hexa fluoro phosphate, Lithium hexa fluoro arsenate monohydrate, Lithium per chlorate, Lithium hexa fluoro borate etc. Depending upon the salt used, the voltage, capacity and life of the battery varies. Pure lithium reacts with water vigorously to form lithium hydroxide and hydrogen ions. So the electrolyte used is non aqueous organic solvent. The electrochemical role of the electrodes charge between anode and cathode depends on the direction of current flow.

Selected design parameters of a thermal management system for a lithium-ion phosphate battery

Selected design parameters of a thermal management system for a lithium-ion phosphate battery

State of health estimation for lithium-ion batteries based on incremental capacity analysis under slight overcharge voltage

Accurate and reliable estimation of state of health (SOH) for lithium-ion batteries under slight overcharge voltage cycling has great significance for battery management systems. In this study, commercial lithium-ion phosphate batteries are investigated under slight overcharge voltage cycling. The aging mechanism is discussed based on incremental capacity analysis and differential voltage analysis. Moreover, the syncretic health indicator is obtained from the incremental capacity curves based on principal component analysis. Specifically, the capacity retention and Coulombic efficiency are analyzed under slight overcharge voltage cycling. The incremental capacity peaks (i.e., peak B and peak C) are discussed to extract potential health indicators, and a syncretic health indicator is adopted based on principal component analysis. Finally, the Gaussian process regression is established for accuracy SOH estimation with a 95% confidence interval under small data of slight overcharge cycling. In comparison with the traditional methods, the proposed method exhibits higher accuracy with a 95% confidence interval, and the error is limited to 3%.

Compatibility of Lithium ion Phosphate Battery in Solar off Grid Application

Solar energy harvesting is practiced by various nations for the purpose of energy security and environment preservation in order to reduce overdependence on oil. Converting solar energy into electrical energy through Photovoltaic (PV) module can take place either in on-grid or off-grid applications. In recent time Lithium battery is exhibiting its presence in on-grid applications but its role in off-grid application is rarely discussed in the literature. The preliminary capacity and Peukert’s study indicated that the battery quality is good and can be subjected for life cycle test. The capacity of the battery was 10.82 Ah at 1 A discharge current and the slope of 1.0117 in the Peukert’s study indicated the reaction is very fast and independent on rate of discharge. In this study Lithium Iron Phosphate battery (LFP) after initial characterization was subjected to life cycle test which is specific to solar off-grid application as defined in IEC standard. The battery has delivered just 6 endurance units at room temperature before its capacity reached 75% of rated value. The low life of LFP battery in off-grid application is discussed based on State of Charge (SOC) operating window. The battery was operated both in high and low SOC’s in off-grid application and both are detrimental to life of lithium battery. High SOC operation resulted in cell-to-cell variation and low SOC operation resulted in lithium plating on negative electrode. It is suggested that to make it more suitable for off-grid applications the battery by default has to be overdesigned by nearly 40% of its rated capacity.

A multi‐objective parallel layered equalizer for large‐scale lithium ion battery system

The equalisers available are difficult to give consideration to both high balance efficiency and fast balance speed, and their performances are unstable as the number of the series-connected batteries increases, so they are unsuitable for a large-scale battery system. A multi-objective parallel layered equaliser based on battery working states for the large-scale lithium-ion battery system is presented. The equaliser has two types of balance objects and two corresponding layers, and the first layer and the second layer take the single battery and the battery unit as the balance object, respectively. The multi-objective parallel layered balance means that multiple balance objects are selected as the balance objectives simultaneously at each layer. The balance speed is fast due to the multi-objective parallel balance. The balance efficiency is high due to the short energy path and the complementary pulse width modulation (PWM) control in the first layer, and the double voltage value of the balance object in the second layer. Moreover, the performance of the equaliser is stable, even when the number of series-connected batteries is large. In short, the proposed equaliser features high efficiency, fast speed, and strong scalability. Further, the experimental platform for a battery system with twelve series-connected lithium-ion phosphate batteries is built, and then the balance experiments have been completed. Finally, the effectiveness of the equaliser is verified by the corresponding experimental results.

Life Cycle Prediction Assessment of Battery Electrical Vehicles with Special Focus on Different Lithium-Ion Power Batteries in China

The incentive policies of new energy vehicles substantially promoted the development of the electrical vehicles technology and industry in China. However, the environmental impact of the key technology parameters progress on the battery electrical vehicles (BEV) is uncertain, and the BEV matching different lithium-ion power batteries shows different environmental burdens. This study conducts a life cycle assessment (LCA) of a BEV matching four different power batteries of lithium-ion phosphate (LFP), lithium-ion nickel-cobalt-manganese (NCM), lithium manganese oxide (LMO), and lithium titanate oxide (LTO) batteries. In addition, the 2025 and 2030 prediction analyses of the batteries production and life cycle BEV are conducted with the specially considered change and progress of the power battery energy density, battery manufacturing energy consumption, electricity structure, battery charge efficiency, and vehicle lightweight level. In addition, sensitivity analyses of power battery energy density, battery manufacturing energy consumption, electricity structure, and battery charge efficiency are conducted. The results show that the LFP battery is more environmentally friendly in the global warming potential (GWP) and acidification potential (AP), and the NCM battery is more environmentally friendly in abiotic depletion (fossil) (ADP(f)) and human toxicity potential (HTP). However, the LTO battery shows the highest environmental impact among the four environmental impact categories due to the lower energy density. For life cycle BEV, GWP and ADP(f) of BEV based on LFP, NCM, and LMO are lower than those of internal combustion engine vehicles (ICEV), while AP and HTP of BEV based on the four batteries are higher than those of ICEV. The grave-to-cradle (GTC) phase of vehicle has substantial environmental benefit to reduce the human toxicity emission. With the improvement of the battery density, battery charge efficiency, electricity structure, and glider lightweight level, life cycle BEVs based on the four different batteries show substantial environmental benefits for four environmental impact categories.

Renewable Energy Source Based Hybrid Power Plant for Electric Vehicle (EV) Charging Station in Rural Area

An electrical vehicle charging station is a charging power supply for electrical vehicles. This paper proposes design of a model for a PV based electrical vehicle that forecasts total power output under particular conditions of Ankara city. First PV cell parameters are determined and then PV array formed including cells designed in order to calculate cumulative effect. Using actual irradiation and temperature values we try to catch an approximation of output power for the future needs. Electric vehicles offer many advantages ranging from easy access and abundance of electrical energy sources. The objective of this paper is to obtain the best configuration of the hybrid power systems for charging station in a rural area such as Labuan bajo, Indonesia. Thus, the best configuration obtained is then installing with three types of energy storage namely Lead Acid and UNS Lithium battery such as Lithium Ion and Lithium Ferro Phosphate (LFP) to determine the minimum cost of operation and energy cost in a year. The results showed by implementing hybrid systems from PV and DER is the best configuration for off grid charging station. The most optimal battery in off grid system achieved by installing UNS LFP batteries. As a conclusion, by utilizing hybrid power generation technology, the potential for renewable energy in rural areas can be the main key in realizing the availability of charging stations in rural areas with affordable price for supporting electric vehicles infrastructure.

Accelerated ion conduction by co-grafting of poly(ethylene glycol) and nitrile-terminated ionic liquid on poly(arylene ether sulfone) for solid electrolyte membranes for lithium ion battery

Solid polymeric electrolytes (SPE) are fabricated from poly(arylene ether sulfone)-co-poly(ethylene glycol)/nitrile terminated ionic liquid (PAES-co-PEG/ILCN) for lithium ion battery. Ionic liquid (IL) based on 1-butyl-1-methylpyrrollidum bis(fluoromethanesulfonyl) imide (Pyr-TFSI) is prepared and blended with 0.5 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) for promotion of the lithium (Li) ion transport in the membrane. Because of the compatibility difference, the synthesized membranes show the phase separation between PAES and PEG/IL components where PAES plays a role as mechanically robust matrix and PEG/IL acts as ion transport pathways. The PAES-co-(PEG70/ILCN30) membrane containing 70 wt% of 0.5 M LiTFSI/Pyr-TFSI illustrates high Li ion conductivity (0.72 × 10−3 S cm−1) with the Li transport number value of 0.38 at room temperature. No thermal de-composition is observed up to 200 °C, maintaining the mechanical flexibility and rigidity with 1.25 MPa of tensile strength and 108% of elongation at fracture. The lithium ion phosphate (LiFePO4/SPE/Li) cell test exhibits the discharge capacity value of 139.7 mAh g−1 and high stable cyclic performance up to 100th cycle at 0.1 C-rate.

State of charge estimation of lithium-ion phosphate battery based on weighted multi-innovation cubature Kalman filter

State of charge (SoC) is one of the most important parameters of battery manage system (BMS). To obtain a better result of SoC estimation, an accurate battery model and effective SoC estimation algorithm are indispensable. In this work, a Thevenin model is established and linear Kalman filter (LKF) is used for online parameters identification. Results show that convergence of parameters identification of LKF is better than that of the recursive least squares (RLS) and recursive least squares with forgetting factor (FFRLS). In addition, the equilibrium potential equation (EPE) is used to fit the relationship between open circuit voltage (OCV) and SoC instead of 9th order polynomial. Then, by the weighted calculation of the innovation vector based on error distribution and time distribution, the weighted multi-innovation cubature Kalman filter (WMICKF) is proposed for the SoC estimation. The experimental data are obtained based on a prismatic LiFePO4 battery, which is tested under urban dynamometer driving schedule (UDDS) test and new European driving cycle (NEDC) test at room temperature. The results show that the WMICKF outperforms the classical cubature Kalman filter (CKF) and the multi-innovation CKF (MICKF). The SoC estimation error of WMICKF can be limited within 1% (0.91%), which is better than 1.30% of CKF and 2.71% of MICKF. In addition, the mean absolute error (MAE), root mean square error (RMSE) and coefficient of determination (R-square) are calculated for comprehensive assessment of the proposed method. Furthermore, the robustness of WMICKF is verified under different initial SoC error and different types of noise disturbance. Results show that under these uncertain factors, the proposed WMICKF is still reliable for accurate SoC estimation.

Encapsulating a Responsive Hydrogel Core for Void Space Modulation in High-Stability Graphene-Wrapped Silicon Anodes.

Due to its formidably high theoretical capacity (3590 mAh/g at room temperature), silicon (Si) is expected to replace graphite as the dominant anode for higher energy density lithium (Li)-ion batteries. However, stability issues stemming from silicon's significant volume expansion (∼300%) upon lithiation have slowed down commercialization. Herein, we report the design of a scalable process to engineer core-shell structures capable of buffering this volume expansion, which utilize a core made up of a poly(ethylene oxide)-carboxymethyl cellulose hydrogel and silicon protected by a crumpled graphene shell. The volume expansion of the hydrogel upon exposure to water creates a void space between the Si-Si and Si-rGO interfaces within the core when the gel dries. Unlike sacrificial spacers, the dehydrated hydrogel remains in the core and acts as an elastic Li-ion conductor, which improves the stability and high rate performance. The optimized composite electrodes retain ∼81.7% of their initial capacity (1055 mAh/(grGO+gel+Si)) after 320 cycles when an active material loading of 1 mg/cm2 is used. At more practical mass loadings (2.5 mg/cm2), the electrodes achieve 2.04 mAh/cm2 and retain 79% of this capacity after 200 cycles against a lithium half-cell. Full cells assembled using a lithium ion phosphate cathode lose only 6.7% of their initial capacity over 100 cycles, demonstrating the potential of this nanocomposite anode for use in next-generation Li-ion batteries.

An evaluation of surface temperature distribution under different charging and discharging modes of the lithium-ion phosphate battery using Thermal Imaging

This study aims to determine the thermal behavior of lithium-ion phosphate (LiFePO4) 20Ah battery by Thermal imaging. This study focuses on day/night charging and discharging to the battery's temperature distribution. The thermal gradient of battery, LiFePO4 powered bike at different speeds 30kmph, 40kmph, 50kmph both load and without load condition. The spatial distribution of LiFePO4 cells was not stable during the discharging process. No significant temperature rise was recorded at the end of the discharge. During the range test at 30kmph, 40kmph, and 50kmph, the maximum surface temperature reached 47.90℃, 44.20℃, and 46.70 ℃, respectively. The battery's front view was most of the highest surface temperature region. The result shows thermal imaging is an effective tool to predict the temperature behavior of batteries and provide a better thermal management system in battery development

Computational fluid dynamics and thermal analysis of a lithium-ion battery with different cooling system for electric vehicles

Lithium-ion batteries are the main bases available for electric vehicles and hybrid electric vehicles, because of clean energy transportation as compared to other power sources developed by traditional I.C Engines. In order to get high discharging Lithium-ion batteries battery condition, there is a significant temperature difference should be maintained in between battery temperature and appropriate local temperature. In this paper presents the model designed with different type of heat pipe shapes modeling in CREO parametric software and analyzes the heat pipe with different mass flow inlets (30& 50L/min) thermal thermal analysis done in ANSYS to determine the temperature distribution and heat flux for two types of phase change materials (RT50 & Li Fe PO 4). Also, Computational Fluid Dynamics analysis (CFD) is to calculate pressure (pa), velocity (m/s), heat transfer coefficient (w/m 2k), mass flow rate (kg/sec) and heat transfer rate (w) for the different designs of heat pipe and different mass flow inlets. It has been observed that in thermal analysis the heat flux value is more for lithium ion phosphate phase change material (Li Fe PO 4) than RT50 phase change material at U-bend heat pipes. Similarly in CFD analysis observed that mass flow rate (kg/sec), heat transfer rate (w), heat transfer coefficient (w/m 2k) values are increases by increasing the mass flow inlets and heat transfer rate more at straight type heat pipes as compared to bend type.

Flame retardant vermiculite coated on polypropylene separator for lithium-ion batteries

Lithium-ion batteries (LIBs) are being used in a variety of applications due to their desirable energy storage characteristics required for modern electronic devices. However, LIBs are prone to thermal runaway due to the flammable liquid electrolyte, decomposition of solid electrolyte interphase from anode surfaces, and melting of polypropylene (PP) separators. The separator provides a pathway for Li+ transfer and divides electrodes from electrical contact, avoiding a short circuit, a potentially catastrophic event. A separator that can endure higher temperatures may restrict a cell from causing thermal runaway. This paper demonstrates that vermiculite, a mineral stable over 1000 °C, could act as a separator lining in LIBs with a lithium-ion phosphate (LFP) cathode and lithium anode. Though the standard PP separator shrinks or melts above 130 °C, the vermiculite and binder will continue to provide electronic isolation, allowing the battery to delay a thermal runaway scenario. The battery containing the vermiculite modified separator released 1.675 kJ g−1 less exothermic energy during the thermal runaway, as well as demonstrating a 3.38 °C higher separator melting temperature, indicating enhanced safety in examined LIBs.

Experimental investigation of thermal performance of novel cold plate design used in a Li-ion pouch-type battery

• Thermal performance of serpentine tube and mini channel cold plates are compared. • Transient average battery temperature change is examined at the various conditions. • The effect of cold plate design on the battery temperature homogeneity is studied. • Low fluid inlet temperatures adversely affect battery temperature uniformity. The world's tendency towards electric vehicles has accelerated and the thermal management of them are critical part of the actual studies. Liquid-based cooling is known as the most common one among other cooling techniques. However, there is still need on the use of various heat transfer enhancement techniques to reduce the maximum temperature and maintain homogenous temperatures. This study experimentally investigated thermal performance of water-cooled cold plates used in thermal management of batteries by using conventional serpentine tube and a novel mini channel designs including a lithium-ion phosphate battery under certain discharge rates from 1C to 5C. Experiments are conducted for different water flow rates from 0.1 to 1.1 L/min as the coolant with inlet temperatures from 15 to 35 °C. Experimental results show that lower coolant inlet temperature causes the largest maximum temperature difference on battery surface. The use of mini channel cold plate resulted in 5.7 °C reduction in the maximum average battery surface temperature compared to serpentine one. Battery surface temperature homogeneity is improved up to 40% for operating conditions for mini channel cold plate usage. Thus, enhancement on thermal performance of proposed new mini channel cold plate is accomplished by temperature measurements.

Temperature Effect and Battery Charging Characteristics Analysis Based on Charging C-Rate

Developing fast charging proprieties for LiFePo4 battery is a key issue for a wider deployment of EV. The main drawback of LiFePo4 battery charging is overcharge, overcurrent and high temperature which affects longevity, efficiency, and battery life cycle. In this research, lithium iron phosphate (LiFePo4) battery is investigated for fast, and rapid charging with CC-CV principle. MATLAB/Simulink based custom-designed tool was developed. A dynamic model of lithium-ion phosphate battery is proposed in this research by considering the significant temperature and capacity fading effects. Results have shown that the LiFePo4 battery can be used for fast charging up to 100% and rapid charging up to 85% by maintaining the condition for lifespan of the battery and to shorten the charging time. The simulation results have been showed that, the constructed model can really represent the dynamic performance feature of the lithium-ion battery. The modified model can assess the efficiency of battery execution based on charging C-rate conditions.

Comparative life cycle assessment of lithium-ion batteries for electric vehicles addressing capacity fade

Lithium-ion batteries are currently used in electric vehicles (EVs) with many advantages; however, batteries contribute significantly to the life cycle environmental impacts of these vehicles. This article presents a comparative life cycle assessment of two types of batteries – lithium manganese oxide (LiMn2O4) and lithium ion phosphate (LiFePO4) – frequently used in EVs, addressing real-life operational conditions and battery capacity fade. The influence of the location of battery manufacturing and vehicle charging (electricity mix) was also assessed. A life cycle model of batteries in an EV with a service life of 200 000 km (functional unit) was implemented to assess Primary Fossil Energy, Global Warming, Acidification, and Eutrophication impacts. Moreover, the environmental performance of EVs considering both battery types was evaluated. The LiFePO4 battery had better operational performance than the LiMn2O4 one and fewer batteries were needed over the EV service life. Conversely, the life cycle impacts of the LiFePO4 batteries were higher than the LiMn2O4 ones mainly due to higher manufacturing impacts. In countries with a mix based on renewable electricity, the battery production is the most important contributor to impacts, while in countries with electricity mostly from fossil sources, the use phase is the most important. For both battery types and most impact categories, the environmental impacts of EVs were highly dependent on the usage scenario and the electricity mix used for charging.

Integrated Size and Energy Management Design of Battery Storage to Enhance Grid Integration of Large-Scale PV Power Plants

Battery storage controlled by an energy management system (EMS) becomes an enabling technique to enhance solar farm integration. In this paper, the EMS controls battery storage to shape the fluctuated photovoltaic (PV) plant output into a relatively constant power and support the peak load. The proposed integrated design method considers both battery size and EMS impacts on the utility benefits and cost. The utility benefits include power generation, peak power support, and reduced line losses. The cost of battery storage is determined by the size and lifetime based on the developed battery models. Accordingly, the utility revenue change due to the battery storage controlled by EMS can be evaluated. Therefore, the integrated design of battery size and EMS can be determined by managing the change of utility revenue to gain economic benefits for the large-scale PV power plant application. Finally, the lithium-ion phosphate (LiFePO4) battery and lead-acid battery are compared to demonstrate the proposed method on a utility system model, respectively.

A study on thermal performance of batteries using thermal imaging and infrared radiation

Abstract This study attempted to improve the performance of pouch-type lithium iron phosphate battery (LiFePO 4 ) through analysis on its degradation mechanism at a high rate (10 C) for the purpose of observing resistance and electrochemical changes in each material when a battery was manufactured considering the low electrical conductivity and of lithium iron phosphate and properties of cathode materials. For this, the life and safety of lithium batteries are evaluated after forming dendrites through the reduction of lithium at the negative electrode (graphite) as resistance in LiFePO 4 . The components of LiFePO 4 , which generate this kind of resistance includes tab, electrolytes, cathode active materials, anode active materials, binders and conductive materials. The main cathode (lithium-ion phosphate) and anode (natural graphite) materials were fabricated in 90% and 96% respectively, using conductive materials and binders. For a case, a 20 Ah Al pouch was fabricated. A full cell was fabricated with the best materials and components through analysis on resistance characteristic. Then, LiFePO 4 was thermally safer with a long lifespan than the conventional high-rate output. For analysis on materials, in addition, basic material analysis was performed through impedance, X-ray diffraction (XRD), X-Scan and field emission scanning electron (FESEM). After tracing heat generated within the battery using infrared radiation (IR), the degree of degradation was examined. Then, the degradation rates of lithium batteries and reliability of measurements were comparatively assessed. When analyzed with an infrared camera, temperature rapidly rose up to over 80 °C during charge and discharge. A battery was fabricated using an industrial engineering method which can secure internal resistance-lowering slurry and coating dispersion processes and reduce resistance in the binder and tab joint. As a result, it was able to substitute conventional LiFePO 4 with high internal resistance, disperse heat inside the cell and increase its lifespan.