Understanding the combustion behavior of electric bicycle batteries and unveiling its relationship with fire extinguishing

In this study,a detailed analysis of the combustion behaviors of the lithium iron phosphate(LFP)and lithium manganese oxide(LMO)batteries used in electric bicycles was conducted.This research included quantitative measurements of the combustion duration,flame height,combustion temperature,heat release rate,and total heat release.The results indicated that LMO batteries exhibited higher combustion temperatures of 600–700°C,flame heights of 70–75 cm,a significantly higher heat release rate of40.1 k W(12 Ah),and a total heat release of 1.04 MJ(12 Ah)compared to LFP batteries with the same capacity.Based on these experimental results,a normalized total heat release(NORTHR)parameter was proposed,demonstrating good universality for batteries with different capacities.Utilizing this parameter,quantitative calculations and optimization of the extinguishing agent dosage were conducted for fires involving these two types of batteries,and the method was validated by extinguishing fires for these two types of battery packs with water-based extinguishing fluids.

Development of the zinc-air power battery on electric bicycles in China

Electric bicycles powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection policy of the lead-acid battery, the zinc-air power battery was proposed to solve the problem in this paper. The advantage and the feasibility of developing zinc-air power batteries in China have been illustrated in the paper. And, it is represented that development of electric bicycles powered by the zinc-air power battery also can accelerate this kind of battery's development in other electric vehicles, which is favorable to economic development and environmental protection.

Factors on Storage Performance of MH-Ni Battery

The open voltage of batteries shows different status after MH-Ni batteries are stored for a period of time.Some batteries with 0, 0.9 ～ 1.1V and above 1.1 V were chosen to study their corresponding internal resistances, open voltages and the reduction of capacities, etc.On the basis of battery reaction principle, battery samples were analyzed,and factors causing different storage performance were found out.Therefore, some references on the improvement of battery storage performance were provided.

Battery Technologies for Grid-Level Large-Scale Electrical Energy Storage

Grid-level large-scale electrical energy storage(GLEES) is an essential approach for balancing the supply–demand of electricity generation, distribution, and usage. Compared with conventional energy storage methods, battery technologies are desirable energy storage devices for GLEES due to their easy modularization, rapid response, flexible installation, and short construction cycles. In general, battery energy storage technologies are expected to meet the requirements of GLEES such as peak shaving and load leveling, voltage and frequency regulation, and emergency response, which are highlighted in this perspective. Furthermore, several types of battery technologies, including lead–acid, nickel–cadmium, nickel–metal hydride, sodium–sulfur, lithium-ion, and flow batteries, are discussed in detail for the application of GLEES. Moreover, some possible developing directions to facilitate efforts in this area are presented to establish a perspective on battery technology, provide a road map for guiding future studies, and promote the commercial application of batteries for GLEES.

Towards Realistic Vibration Testing of Large Floor Batteries for Battery Electric Vehicles (BEV)

This contribution shows an analysis of vibration measurement on large floor-mounted traction batteries of Battery Electric Vehicles(BEV).The focus lies on the requirements for a realistic replication of the mechanical environments in a testing laboratory.Especially the analysis on global bending transfer functions and local corner bending coherence indicate that neither a fully stiff fixation of the battery nor a completely independent movement on the four corners yields a realistic and conservative test scenario.The contribution will further show what implication these findings have on future vibration&shock testing equipment for large traction batteries.Additionally,it will cover an outlook on how vibration behavior of highly integrated approaches(cell2car)changes the mechanical loads on the cells.

Research of heat treatment of low-Co AB_5 type hydrogen storage alloys for MH-Ni batteries

The effects of low-Co AB_5 type hydrogen storage alloys prepared by quenchingand annealing on the performances of MH-Ni batteries were investigated, and the characteristics ofthe low-Co AB_5 type hydrogen storage alloys were compared with those of the high-Co AB_5 typehydrogen storage alloy as well. The results showed that the faster the cooling of the low-Cohydrogen storage alloy is, the better homogeneity of the chemical composition for the alloy and thelonger cycle life of the battery are, but the electrochemical discharge capacity and high-ratedischarge ability are reduced. The high-rate discharge ability and charge retention of MH-Nibatteries for the conventional as-cast annealed low-Co hydrogen storage alloy were superior to thosefor the rapidly quenched low-Co hydrogen storage alloy and the high-Co hydrogen storage alloy, buta little inferior in the cycle life.

Method of Electric Powertrain Matching for Battery-powered Electric Cars

The current match method of electric powertrain still makes use of longitudinal dynamics, which can’t realize maximum capacity for on-board energy storage unit and can’t reach lowest equivalent fuel consumption as well. Another match method focuses on improving available space considering reasonable layout of vehicle to enlarge rated energy capacity for on-board energy storage unit, which can keep the longitudinal dynamics performance almost unchanged but can’t reach lowest fuel consumption. Considering the characteristics of driving motor, method of electric powertrain matching utilizing conventional longitudinal dynamics for driving system and cut-and-try method for energy storage system is proposed for passenger cars converted from traditional ones. Through combining the utilization of vehicle space which contributes to the on-board energy amount, vehicle longitudinal performance requirements, vehicle equivalent fuel consumption level, passive safety requirements and maximum driving range requirement together, a comprehensive optimal match method of electric powertrain for battery-powered electric vehicle is raised. In simulation, the vehicle model and match method is built in Matlab/simulink, and the Environmental Protection Agency (EPA) Urban Dynamometer Driving Schedule (UDDS) is chosen as a test condition. The simulation results show that 2.62% of regenerative energy and 2% of energy storage efficiency are increased relative to the traditional method. The research conclusions provide theoretical and practical solutions for electric powertrain matching for modern battery-powered electric vehicles especially for those converted from traditional ones, and further enhance dynamics of electric vehicles.

Analysis of Hybrid Rechargeable Energy Storage Systems in Series Plug-In Hybrid Electric Vehicles Based on Simulations

In this paper, an extended analysis of the performance of different hybrid Rechargeable Energy Storage Systems (RESS) for use in Plug-in Hybrid Electric Vehicle (PHEV) with a series drivetrain topology is analyzed, based on simulations with three different driving cycles. The investigated hybrid energy storage topologies are an energy optimized lithium-ion battery (HE) in combination with an Electrical Double-Layer Capacitor (EDLC) system, in combination with a power optimized lithium-ion battery (HP) system or in combination with a Lithium-ion Capacitor (LiCap) system, that act as a Peak Power System. From the simulation results it was observed that hybridization of the HE lithium-ion based energy storage system resulted from the three topologies in an increased overall energy efficiency of the RESS, in an extended all electric range of the PHEV and in a reduced average current through the HE battery. The lowest consumption during the three driving cycles was obtained for the HE-LiCap topology, where fuel savings of respectively 6.0%, 10.3% and 6.8% compared with the battery stand-alone system were achieved. The largest extension of the range was achieved for the HE-HP configuration (17% based on FTP-75 driving cycle). HP batteries however have a large internal resistance in comparison to EDLC and LiCap systems, which resulted in a reduced overall energy efficiency of the hybrid RESS. Additionally, it was observed that the HP and LiCap systems both offer significant benefits for the integration of a peak power system in the drivetrain of a Plug-in Hybrid Electric Vehicle due to their low volume and weight in comparison to that of the EDLC system.

Progress and prospect for NASICON-type Na3V2(PO4)3 forelectrochemical energy storage

Sodium-ion batteries （SIBs） have attracted increasing attention in the past decades, because of high over-all abundance of precursors, their even geographical distribution, and low cost. Na3V2（PO4）3 （NVP）, atypical sodium super ion conductor （NASlCON）-based electrode material, exhibits pronounced structuralstability, exceptionally high ion conductivity, rendering it a most promising electrode for sodium storage.However. the comparatively low electronic conductivity makes the theoretical capacity of NVP cannot befully accessible even at comparatively low rates, presenting a major drawback for further practical ap-plications, especially when high rate capability is especially important. Thus, many endeavors have beenconformed to increase the surface and intrinsic electrical conductivity of NVP by coating the active mate-rials with a conductive carbon layer, downsizing the NVP particles, combining the NVP particle with vari-ous carbon materials and ion doping strategy. In this review, to get a better understanding on the sodiumstorage in NVP, we firstly present 4 distinct crystal structures in the temperature range of-30℃-225℃ namely α-NVP, β-NVP, β′-NVP and γ-NVP. Moreover, we give an overview of recent approaches to en-hance the surface electrical conductivity and intrinsic electrical conductivity of NVP. Finally, some poten-tial applications of NVP such as in all-climate environment and PHEV, EV fields have been prospected.

Constructing Carbon Nanobubbles with Boron Doping as Advanced Anode for Realizing Unprecedently Ultrafast Potassium Ion Storage

Carbonaceous material with favorable K^(+)intercalation feature is considered as a compelling anode for potassium-ion batteries(PIBs).However,the inferior rate performance and cycling stability impede their large-scale application.Here,a facile template method is utilized to synthesize boron doping carbon nanobubbles(BCNBs).The incorporation of boron into the carbon structure introduces abundant defective sites and improves conductivity,facilitating both the intercalation-controlled and capacitivecontrolled capacities.Moreover,theoretical calculation proves that boron doping can effectively improve the conductivity and facilitate electrochemical reversibility in PIBs.Correspondingly,the designed BCNBs anode delivers a high specific capacity(464 mAh g^(-1)at 0.05 A g^(-1))with an extraordinary rate performance(85.7 mAh g^(-1)at 50 A g^(-1)),and retains a considerable capacity retention(95.2%relative to the 100th charge after 2000 cycles).Besides,the strategy of pre-forming stable artificial inorganic solid electrolyte interface effectively realizes high initial coulombic efficiency of 79.0%for BCNBs.Impressively,a dual-carbon potassium-ion capacitor coupling BCNBs anode displays a high energy density(177.8 Wh kg^(-1)).This work not only shows great potential for utilizing heteroatom-doping strategy to boost the potassium ion storage but also paves the way for designing high-energy/power storage devices.

Zn-air batteries for electric vehicles

The increasingly serious environmental challenges have gradually aroused people's interest in electric vehicles.Over the last decade,governments and automakers have collaborated on the manufacturing of electric vehicles with high performance.Cutting-edge battery technologies are pivotal for the performance of electric vehicles.Zn-air batteries are considered as potential power batteries for electric vehicles due to their high capacity.Zn-air battery researches can be classified into three categories:primary batteries,mechanically rechargeable batteries,and chemically rechargeable batteries.The majority of current studies aim at developing and improving chemically rechargeable and mechanically rechargeable Zn-air batteries.Researchers have tried to use catalytic materials design and device design for Zn-air batteries to make it possible for their applications in electric vehicles.This review will highlight the state-of-the-art in primary batteries,mechanically rechargeable batteries,and chemically rechargeable batteries,revealing the prospects of Zn-air batteries for electric vehicles.

Multi-Scale Fusion Model Based on Gated Recurrent Unit for Enhancing Prediction Accuracy of State-of-Charge in Battery Energy Storage Systems

Accurate prediction of the state-of-charge(SOC)of battery energy storage system(BESS)is critical for its safety and lifespan in electric vehicles.To overcome the imbalance of existing methods between multi-scale feature fusion and global feature extraction,this paper introduces a novel multi-scale fusion(MSF)model based on gated recurrent unit(GRU),which is specifically designed for complex multi-step SOC prediction in practical BESSs.Pearson correlation analysis is first employed to identify SOC-related parameters.These parameters are then input into a multi-layer GRU for point-wise feature extraction.Concurrently,the parameters undergo patching before entering a dual-stage multi-layer GRU,thus enabling the model to capture nuanced information across varying time intervals.Ultimately,by means of adaptive weight fusion and a fully connected network,multi-step SOC predictions are rendered.Following extensive validation over multiple days,it is illustrated that the proposed model achieves an absolute error of less than 1.5%in real-time SOC prediction.

DESIGN AND EXPERIMENT OF ELECTRIC BUS

Performance and reliability experiments on BJD-6100EV electric buses, jointlydeveloped by Beijing Institute of Technology and Beijing Public Transport Company, are introduced.Output power model of battery pack is established and maximum output power is analyzed. A permanentmagnetic direct current (PMDC) motor with enhanced windings is developed for the bus. Torque-speedcharacteristics of the motor are modeled and performance of electric bus is analyzed. Computationalmethod of the range of electric bus is proposed and discussed. Experiments show that electric buscan realize design requirements. Computational methods are verified with the help of field test. Itis expected that design and computation method will provide helpful reference to development ofelectric vehicles.

A Comprehensive Analysis of Plug in Hybrid Electric Vehicles to Commercial Campus (V2C)

Vehicle to grid is an emerging technology that utilizes plug in hybrid electric vehicle batteries to benefit electric utilities during times when the vehicle is parked and connected to the electric grid. In its current form however, vehicle to grid implementation poses many challenges that may not be easily overcome and many existing studies neglect critical aspects such as battery cost or driving profiles. The goal of this research is to ease some of these challenges by examining a vehicle to grid scenario on a university campus, as an example of a commercial campus, based on time of use electricity rates. An analysis of this scenario is conducted on a vehicle battery as well as a stationary battery for comparison. It is found that vehicle to campus and a stationary battery both have the potential to prove economical based on battery cost and electricity rates.

Critical review and functional safety of a battery management system for large‑scale lithium‑ion battery pack technologies

The battery management system(BMS)is the main safeguard of a battery system for electric propulsion and machine electrifcation.It is tasked to ensure reliable and safe operation of battery cells connected to provide high currents at high voltage levels.In addition to efectively monitoring all the electrical parameters of a battery pack system,such as the voltage,current,and temperature,the BMS is also used to improve the battery performance with proper safety measures within the system.With growing acceptance of lithium-ion batteries,major industry sectors such as the automotive,renewable energy,manufacturing,construction,and even some in the mining industry have brought forward the mass transition from fossil fuel dependency to electric powered machinery and redefned the world of energy storage.Hence,the functional safety considerations,which are those relating to automatic protection,in battery management for battery pack technologies are particularly important to ensure that the overall electrical system,regardless of whether it is for electric transportation or stationary energy storage,is in accordance with high standards of safety,reliability,and quality.If the system or product fails to meet functional and other safety requirements on account of faulty design or a sequence of failure events,then the environment,people,and property could be endangered.This paper analyzed the details of BMS for electric transportation and large-scale energy storage systems,particularly in areas concerned with hazardous environment.The analysis covers the aspect of functional safety that applies to BMS and is in accordance with the relevant industrial standards.A comprehensive evaluation of the components,architecture,risk reduction techniques,and failure mode analysis applicable to BMS operation was also presented.The article further provided recommendations on safety design and performance optimization in relation to the overall BMS integration.

Electricity Tariff Aware Model Predictive Controller for Customer Battery Storage with Uncertain Daily Cycling Load

To optimally control the energy storage system of the battery exposed to the volatile daily cycling load and electricity tariffs,a novel modification of a conventional model predictive control is proposed.The uncertainty of daily cycling load prompts the need to design a new cost function which is able to quantify the associated uncertainty.By modelling a probabilistic dependence among flow,load,and electricity tariffs,the expected cost function is obtained and used in the constrained optimization.The proposed control strategy explicitly incorporates the cycling nature of customer load.Furthermore,for daily cycling load,a fixed-end time and a fixed-end output problem are addressed.It is demonstrated that the proposed control strategy is a convex optimization problem.While stochastic and robust model predictive controllers evaluate the cost concerning model constraints and parameter variations.Also,the expected cost across the flow variations is considered.The density function of load probability improves load prediction over a progressive prediction horizon,and a nonlinear battery model is utilized.

The General Configuration of CEV1 Electric Vehicle's Electrical System and the Design of Its Control Sequence

The general configuration of CEV1 electric vehicle’s electrical system and the design scheme of its control sequence are presented, which are modularized by using VMU as master control unit, PMU as power management unit, BMU as battery management unit. It is a rather advanced and practical general design scheme of electric vehicle, because the division of its module function is definite, which is advantage for research, manufacture and maintenance.