Battery Power System Research Articles

Challenges of Fast Charging for Electric Vehicles and the Role of Red Phosphorous as Anode Material: Review

Electric vehicles (EVs) are being endorsed as the uppermost successor to fuel-powered cars, with timetables for banning the sale of petrol-fueled vehicles announced in many countries. However, the range and charging times of EVs are still considerable concerns. Fast charging could be a solution to consumers’ range anxiety and the acceptance of EVs. Nevertheless, it is a complicated and systematized challenge to realize the fast charging of EVs because it includes the coordinated development of battery cells, including electrode materials, EV battery power systems, charging piles, electric grids, etc. This paper aims to serve as an analysis for the development of fast-charging technology, with a discussion of the current situation, constraints and development direction of EV fast-charging technologies from the macroscale and microscale perspectives of fast-charging challenges. If the problem of fast-charging can be solved, it will satisfy consumers’ demand for 10-min charging and accelerate the development of electric vehicles. This paper summarized the development statuses, issues, and trends of the macro battery technology and micro battery technology. It is emphasized that to essentially solve the problem of fast charging, the development of new battery materials, especially anode materials with improved lithium ion diffusion coefficients, is the key. Finally, it is highlighted that red phosphorus is one of the most promising anodes that can simultaneously satisfy the double standards of high-energy density and fast-charging performance to a maximum degree.

Thermal state-of-expansion or melting of phase change material based heat sink for underwater battery power system

Abstract This paper introduces a phase change material (PCM) based heat sink (PCMHS) to reduce the idle and operating temperature of a direct current (DC)/DC converter in an underwater battery power system. The developed macro-encapsulated PCM enclosure features a dampening assembly that maximizes thermal contact and eliminates void space catered for volumetric expansion of the PCM during melting. The operating temperature of the DC/DC converter at steady-state (both idle and full-load cycle condition) is estimated via a validated thermal model. A percentage improvement of at least 27% can be achieved by PCMHS at different load cycle conditions tested. The PCM's volume expansion of approximately 6.4% corresponds to the measured cover movement of around 3 mm. The relationship between the state of expansion (or melt state) to solid-state of the PCM is also established.

Complete design space exploration of isolated hybrid renewable energy system via dynamic programming

The electrical demand of isolated regions without connection to the main grid is usually satisfied by a diesel generator. By replacing this conventional system with a hybrid renewable energy system (HRES) including renewable power generators and battery system, the initial cost increases due to additional components. The operating cost, in contrast, can be reduced by minimizing fuel consumption. The economic viability of HRES, therefore, is heavily dependent on both component sizing and energy dispatch strategy. In order to calculate the minimal operating cost, the control trajectory has to be optimized for each design. Within the common publications, the optimal design is not determined based on optimal control trajectory, but using simple rule-based (RB) or advanced RB control. Furthermore, the correlation between component sizing and economic performance is not identified clearly. In this paper, the complete design space for HRES is explored by dynamic programming (DP) based optimal control. In this way, it is guaranteed that the economic performance of each design is deduced from its full potential and the fair comparison among different designs is enabled. The economic performance is evaluated based on four economic parameters including initial cost, operating & maintenance cost, life cycle cost (LCC), and the payback time (PBT). Based on simulation results using DP, the influence of component sizing on each economic parameter is systematically studied. The simulation results show the overall economic performance is determined by the size of renewable power generator and battery storage, whereby diesel generator plays a minor role. Since the LCC and PBT are dominated by initial cost rather than operating cost, small component sizes are preferred minimizing the wasted dump power. Finally, the impact of energy dispatch strategy is investigated by comparing DP based optimal control with simple RB and advanced RB control. Although the loss of optimality using advanced RB control is negligible within 3%, the application of simple RB control suffers from an optimality loss of 7–16%.

Synthesis and electrochemical properties of Li2FeSiO4/C/Ag composite as a cathode material for Li-ion battery

Li2FeSiO4 is deemed to be a potential candidate for large-scale applications because of its abundance, low cost and high safety, etc. Unfortunately, its low conductivity, resulting in poor rate performance, has become a main obstacle to its applications in power battery and energy storage system. In this work, C-Ag coated Li2FeSiO4 is introduced to improve the innate electronic conductivity and Li-ion diffusion ability. The results demonstrate that Li2FeSiO4/C/Ag composite exhibits better electrochemical performance. It possesses a specific discharge capacity of 152, 121, 108 mA∙h/g at 0.2C, 5C and 10C, respectively. At the same time, the Li2FeSiO4 /C/Ag composite shows good cycle stability and a capacity retention ratio of 97.9% after 100 cycles at 1C.

Development of a degradation-conscious physics-based lithium-ion battery model for use in power system planning studies

A computationally-efficient and reliable method is developed to permit the simultaneous assessment of both the short- and long-term performance of lithium-ion battery in power system planning studies. Toward this end, a physics-based equivalent circuit model of the lithium-ion battery is derived in which side reaction-induced degradation of the battery is included. Whence a computational procedure is developed to enable the parametric values of the circuit elements in the equivalent circuit model to be automatically updated as the battery operates. The resulting model allows the increase in the internal resistance and the decrease in the energy storage capacity of the battery to be determined, based solely on the information of the power flows at the battery terminals. Dynamic simulation results obtained using the developed equivalent circuit model are shown to be in close agreement with those obtained from well-established electrochemical models, but at a much reduced computational burden.

System design of underwater battery power system for marine and offshore industry

Abstract Application of battery power systems increases in the marine and offshore industry. Most applications target to reduce the energy consumptions when the battery power system is wholly or partially used. The hardware and software of the battery power system design for underwater application are described. The testing of the battery power system is successfully performed in a water tank at low temperature of 4 °C that mimics subsea operating condition where most remotely-operated vehicle (ROV) operates. The average variation of state-of-charge for the 12-cell is approximately 5 percent after active cell balancing. The battery management system is capable of estimating the state-of-charge and using the data to perform the active cell balancing on each cell with different imbalanced state-of-charge values of at least 30 percent.

Design of a multifunctional composite structure for modular CubeSat applications

CubeSats primary structures are usually made with aluminium alloys, with few examples of CFRP primary structures under study. Power system battery arrays usually occupy spacecraft internal volume and mass that should be available to the payload. A CFRP structural/battery array configuration has been designed, allowing to integrate the electrical power system in the bus primary structure. Its configuration has been developed with the modular design philosophy of the AraMiS CubeSat. It is sized as a tile, mounted on an external face of the 1U CubeSat. It accommodates two solar cells, while the opposite face accommodates power system circuitry. Following a cellular structure concept, a set of commercial LiPo batteries has been placed between two CFRP panels and spaced out with CFRP ribs. Compliance with launch mechanical loads has been evaluated with a finite element analysis. A preliminary thermal analysis has been performed to simulate a LEO orbit environment. The results indicate that even with a low degree of structural integration, more volume and mass can be allocated to the payload, with respect to traditional, functionally separated designs in aluminium alloy. The low degree of integration allows to employ relatively cheap, commercial off-the-shelf components.

Energy Consumption and Life Cycle Costs of Overhead Catenary Heavy-Duty Trucks for Long-Haul Transportation

The overhead catenary truck is an interesting technology for long-haul transportation with heavy-duty trucks because it can combine the advantage of energy supply via catenary while driving and the flexibility of a battery truck on routes without catenary using the traction battery. This study investigates the energy consumptions of overhead catenary trucks on German highways and considers different configurations for the traction battery and catenary power system. Afterwards the life cycle costs of overhead catenary trucks are calculated for a specified long-haul transportation scenario and the results are compared to battery electric truck and diesel truck using the findings of a previous study by the authors. The energy consumption of the considered overhead catenary trucks is approximately equal to that of a battery electric truck but only about a half of the equivalent energy consumption of a conventional diesel truck. According to the cost assumptions in this study, the total life cycle costs of overhead catenary trucks can be in the range of the conventional diesel truck, showing the competitiveness of this alternative truck technology.

Modeling of Hybrid-Renewable Energy Sources of Linear Load System

A representation of mixture power system based on a photovoltaic, airstream system, a battery bank, and a DC motor-pump is established in this work. The major purpose is to get together the power load requirements through successful employment of the batteries. In this employment, recognition and reproduction of a hybrid solar, wind and storage battery power system is offered. This procedure likewise incorporates a battery stockpiling DC source convert to air conditioning supply to stack through an inverter. The proposed control approach has been embedded by recreation under the equivalent metrological conditions, demonstrating the adequacy of the proposed half and half framework. Reenactment results gotten by MATLAB/SIMULINK programming are displayed.

Bidirectional Interleaved PWM Converter with High Voltage-Conversion Ratio and Automatic Current Balancing Capability for Single-Cell Battery Power System in Small Scientific Satellites

Single-cell battery power systems are a promising bus architecture for small scientific satellites. However, to bridge the huge voltage gap between a single-cell battery and power bus, bidirectional converters with a high voltage conversion ratio and a large current capability for the low-voltage side are necessary. This article proposes a bidirectional interleaved pulse width modulation (PWM) converter with a high voltage conversion ratio and an automatic current balancing capability. By adding capacitors to conventional interleaved PWM converters, not only are inductor currents automatically balanced without feedback control or current sensors, but also voltage conversion ratios at a given duty cycle can be enhanced. Furthermore, the added capacitors can reduce voltage stresses of switches and charged-discharged energies of inductors, realizing more efficient power conversion and reduced circuit volume in comparison with conventional converters. A 100-W prototype was built for experimental verification, and results demonstrated the fundamental characteristics and efficacy of the proposed converter.

Photovoltaic Power Systems Optimization Research Status: A Review of Criteria, Constrains, Models, Techniques, and Software Tools

The photovoltaic (PV) generating system has high potential, since the system is clean, environmental friendly and has secure energy sources. There are two types of PV system, which are grid connected and standalone systems. In the grid connected photovoltaic system (GCPV), PV generator supplies power to the grid, whether or not the whole or a portion of the generated energy will be used to supply load demands. Meanwhile, the standalone photovoltaic system (SAPV) is used to fulfil a load demand that close to its point of use. These days, many researchers study in term of optimization sizing of photovoltaic system, in order to select optimum number of PV modules, inverter, battery storage capacity, and tilt angle. Based on that, this review aims to give explanations on approaches done by previous researchers in order to find ultimate combinations for design parameters. Moreover, the paper discusses on modelling of PV system components, which includes PV panels’ output power estimation and battery system. Finally, simulation softwares that used as sizing tools in previous studies are reviewed and studied.

Nonlinear Temperature-Dependent State Model of Cylindrical LiFePO4 Battery for Open-Circuit Voltage, Terminal Voltage and State-of-Charge Estimation with Extended Kalman Filter

Ambient temperature affects the performance of a battery power system and its accuracy in state-of-charge (SOC) estimation for electric vehicles and smart grid systems. This paper proposes a battery model that considered ambient temperature, cell temperature, hysteresis voltage and thermal aging on capacity due to multiple charging and discharging. The SOC is then estimated using an extended Kalman filter. Several forms of validation were tested on an actual cell battery under specific ambient temperatures to verify the battery cell model, terminal voltage and SOC estimation performance. The SOC estimation results show an improvement in root-mean-squared error as compared to Extended Kalman Filter (EKF) without considering the temperature dependency. The proposed battery temperature-dependent model gave a smaller root-mean square error in SOC and terminal voltage at 5 °C, 15 °C and 45 °C.

Self-sufficiency of 3-D printers: utilizing stand-alone solar photovoltaic power systems

A self-replicating rapid prototyper (RepRap) is a type of 3-D printer capable of printing many of its own components in addition to a wide assortment of products from high-value scientific or medical tools to household products and toys. There is some evidence that these printers could provide low-cost distributed manufacturing in underprivileged rural areas. For the most isolated communities without access to the electric grid, a low-cost alternative energy is needed. Solar energy can be harvested through a stand-alone photovoltaic (PV) power system specifically designed to match the needs of the RepRap. The voltage and current requirement for the printer demands the use of buck along with a bidirectional DC converters to ensure proper operation. This paper provides the design for a stand-alone PV—lithium ion battery power system with an efficient controller. Robust and agile PI controller schemes are utilized to efficiently maintain the distribution of energy through the power system. The system was defined with ordinary differential equations, simulated and tested for two operational conditions in MATLAB/Simulink. The results showed that the controller developed operates the system in a stable condition and the simulation shows steady acceptable behavior that makes this system highly suitable for hardware implementation.

Experimental investigation on the online fuzzy energy management of hybrid fuel cell/battery power system for UAVs

The hybrid powerplant combining a fuel cell and a battery has become one of the most promising alternative power systems for electric unmanned aerial vehicles (UAVs). To enhance the fuel efficiency and battery service life, highly effective and robust online energy management strategies are needed in real applications.In this work, an energy management system is designed to control the hybrid fuel cell and battery power system for electric UAVs. To reduce the weight, only one programmable direct-current to direct-current (dcdc) converter is used as the critical power split component to implement the power management strategy. The output voltage and current of the dcdc is controlled by an independent energy management controller. An executable process of online fuzzy energy management strategy is proposed and established. According to the demand power and battery state of charge, the online fuzzy energy management strategy produces the current command for the dcdc to directly control the output current of the fuel cell and to indirectly control the charge/discharge current of the battery based on the power balance principle.Another two online strategies, the passive control strategy and the state machine strategy, are also employed to compare with the proposed online fuzzy strategy in terms of the battery management and fuel efficiency. To evaluate and compare the feasibility of the online energy management strategies in application, experiments with three types of missions are carried out using the hybrid power system test-bench, which consists of a commercial fuel cell EOS600, a Lipo battery, a programmable dcdc converter, an energy management controller, and an electric load. The experimental investigation shows that the proposed online fuzzy strategy prefers to use the most power from the battery and consumes the least amount of hydrogen fuel compared with the other two online energy management strategies.

Evaluation of battery inconsistency based on information entropy

The power battery system is the core for electric vehicles, which is composed by hundreds or thousands of cells in series and parallel generally. Cells have inherent inconsistency because of slight deviations and uncertain factors in their production process. And they work in the complicated charge and discharge environment for a long time, so their inconsistency will be further aggravated to greatly reduce the available capacity and shorten the service life. There is an urgent need to establish an evaluation mechanism for the inconsistency of batteries to provide the gist for the high-efficiency and reliable management. The test platform and scheme are built to obtain accurate data. And a comprehensive evaluation method for battery inconsistency is proposed based on the information entropy. Taking the capacity, internal resistance and the ratio of constant current charge capacity to constant voltage charge capacity as evaluation factors, the inconsistency of the battery pack composed of twelve cells is analyzed comprehensively. Experimental results show that the method can scientifically evaluate the inconsistency of the battery pack in different life and has wide adaptability.

Development and Test Application of an Auxiliary Power-Integrated System

This paper focuses on the design and test technique of an auxiliary power unit (APU) for a range-extended electric vehicle (RE-EV). The APU system is designed to improve RE-EV power and economy; it integrates the power system, generator system, battery system, and APU controller. The parameters of the APU parts are computed and optimized considering the vehicle power demand and the matching characteristic of the engine and generator. The hardware and software systems are developed for the APU-integrated control system. The APU test bench, combined with the displaying part, the control part, and the bench with its accessory, is constructed. Communication connection in the APU system is established by controller area network (CAN) bus. The APU controller outputs a corresponding signal to the engine control unit (ECU) and motor controller. To verify the rationality of the control strategy and the validity of the control logic, the engine speed control and integrated control experiment of the APU system are completed on the test bench. The test results showed that the test control system is reliable and the relevant control logic is in agreement with simulation analysis. The APU-integrated system could be well suited for application in RE-EVs.

Economic evaluation toward zero CO2 emission power generation system after 2050 in Japan

The costs of renewable energy and battery systems have been reduced. However, further technological developments are required to establish an economical, stable and reliable power grid system through the large-scale introduction of renewable energy systems. This study aims to evaluate the power costs for a high ratio of renewable energy and close to zero CO2 emissions by considering the stability of the electric grid system in Japan. An optimal multi-region power generation model had been developed that based on the system stability of this analysis. For future technological and economic evaluation of renewable energy, a technological evaluation method was used that was based on a manufacturing technology database developed by the Center for low carbon society strategy (LCS) and the following results were obtained. In 2050 CO2 emissions from the electric power system can be reduced by 85% at almost the same power cost as that incurred in 2013. Even if the renewable energy technology stagnates by that time, an 80% CO2 emission reduction can be achieved at low cost. In particular, photovoltaic power systems (PVs) and battery systems will contribute to the establishment of a cost effective and low carbon power generation system. Scenarios in which the annual power consumptions are as high as 800 TWh, PVs accounting for more than 300 GW have been installed which are equivalent to over 30% of total power consumption. The capacity of installed battery systems is taken as 300-500 GWh, and supplies 10%-30 % of the total power consumption. However, the power cost sharply increases when CO2 emissions are reduced by more than 90%. To achieve a zero emission power generation system after 2050, it is necessary to develop hot dry rock geothermal power generation, to reduce power demand and to establish the rationalization of the grid system. These results show the effectiveness of the quantitative evaluation and planning of a low carbon power supply system when the system stability is considered in this methodology.

Lithium Iron Phosphate (LiFePO4) Battery Power System for Deepwater Emergency Operation

Unmanned underwater vehicles (UUV) are widely used for survey and mining of natural resources in the region of underwater and seabed in the last two decades. In underwater, vision and depth perception will be poor, thus navigating and maneuvering a remotely operated vehicles (ROVs) will not be an easy task. The umbilical cable might get entangled. In the event that the ROV loses power from its umbilical cord or an autonomous underwater vehicle (AUV) power failure, an emergency power system will be needed to power the critical equipment on the ROV or AUV to facilitate its recovery and to limit the loss of data.In this paper, a large format 2 KWh lithium iron phosphate (LiFePO4) battery stack power system is proposed for the emergency power system of the UUV. The LiFePO4 stacks are chosen due to their high energy density, modularity and ready availability. The proposed LiFePO4 battery system includes the design and development of a smart battery management system (BMS) with high efficiency active cell balancing technology and intelligent self-learning battery state of charge (SOC) estimation for the LiFePO4 battery. The proposed BMS will lead to better utilization of battery’s potential capacity and maximize the cycle life of the battery. The battery system has a pressure-resistance enclosure to eliminate extra battery pressure chamber and associated risks, therefore increase the reliability of the power system amidst high pressures down to 3km of deep-water.

A High Stability Optical Shadow Sensor With Applications for Precision Accelerometers

Gravimeters are devices which measure changes in the value of the gravitational acceleration, \textit{g}. This information is used to infer changes in density under the ground allowing the detection of subsurface voids; mineral, oil and gas reserves; and even the detection of the precursors of volcanic eruptions. A micro-electro mechanical system (MEMS) gravimeter has been fabricated completely in silicon allowing the possibility of cost e-effective, lightweight and small gravimeters. To obtain a measurement of gravity, a highly stable displacement measurement of the MEMS is required. This requires the development of a portable electronics system that has a displacement sensitivity of $\leq 2.5$ nm over a period of a day or more. The portable electronics system presented here has a displacement sensitivity $\leq 10$ nm$/\sqrt{\textrm{Hz}}$ ($\leq 0.6$ nm at $1000$ s). The battery power system used a modulated LED for measurements and required temperature control of the system to $\pm$ 2 mK, monitoring of the tilt to $\pm$ 2 $\mu$radians, the storage of measured data and the transmission of the data to an external server.

EMI Radiation Mechanism and Experimental Research of Power Battery System

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