Low-speed Electric Vehicles Research Articles

Lithium-Doping Stabilized High-Performance P2-Na0.66Li0.18Fe0.12Mn0.7O2 Cathode for Sodium Ion Batteries.

While sodium-ion batteries (SIBs) hold great promise for large-scale electric energy storage and low speed electric vehicles, the poor capacity retention of the cathode is one of the bottlenecks in the development of SIBs. Following a strategy of using lithium doping in the transition-metal layer to stabilize the desodiated structure, we have designed and successfully synthesized a novel layered oxide cathode P2-Na0.66Li0.18Fe0.12Mn0.7O2, which demonstrated a high capacity of 190 mAh g-1 and a remarkably high capacity retention of ∼87% after 80 cycles within a wide voltage range of 1.5-4.5 V. The outstanding stability is attributed to the reversible migration of lithium during cycling and the elimination of the detrimental P2-O2 phasetransition, revealed by ex situ and in situ X-ray diffraction and solid-state nuclear magnetic resonance spectroscopy.

Optimal Design of Saturated Switched Reluctance Machine for Low Speed Electric Vehicles by Subset Quasi-Orthogonal Algorithm

This paper investigates the optimal design method of switched reluctance machines (SRMs) for mitigating torque ripple and improving average torque under the low speed operation. In order to produce high torque for hill climbing or overload start-up of micro electric vehicles (EVs) and reduce the converter capacity, an SRM with four times torque overload capability and two times speed range with constant power is needed. To improve the SRM performance, first, a new method called multiphase excitation (MPE) method for calculating resultant static torque is adopted, which takes the cross-coupling and magnetic saturation into consideration to reduce the calculation error bought by the traditional method called single-phase excitation (SPE) method; second, optimal methods, including parameters sensitivity analysis, multi-objective optimization function, and winding connection types, have been taken to release the magnetic saturation, to improve average torque, and to depress torque ripple. Compared with the initial scheme, the torque ripple is minimized from 55.33% to 14.84% and the average torque is improved by 8.36%. The experimental results validate the effectiveness of the proposed methods.

Multiobjective Optimization Design of a Switched Reluctance Motor for Low-Speed Electric Vehicles With a Taguchi–CSO Algorithm

This paper proposes a novel multiobjective optimization design method for a switched reluctance motor (SRM) on low-speed electric vehicles (EVs). According to the indexes of a low-speed EVs propulsion system and the large torque ripple of the SRM, six objectives of geometric parameters optimization of the SRM are given, which are maximum speed, acceleration time (including in situ acceleration time and overtake acceleration time), maximum climbing gradient, energy usage ratio, and torque ripple factor. The rated parameters of the driving motor are given based on the basic parameters of the low-speed EVs. Based on the engineering design method, the dimension range of the SRM under the rated parameter range is confirmed. The dynamic simulation model of a low-speed pure EVs propulsion system is built in MATLAB/Simulink based on the finite element model of the SRM and the vehicle balance equation. Then, a multiobjective optimization design of the geometric parameters of the SRM is carried out by a Taguchi-chicken swarm optimization algorithm. The correctness of the finite element model is verified, and the accuracy of the multiobjective optimization is verified by the dynamic simulation results and the low-speed EV experiment.

The influence of battery degradation level on the selected traction parameters of a light-duty electric vehicle

The article describes results of an analysis of the impact of degradation level of battery made in lead-acid technology on selected traction parameters of an electric light duty vehicle. Lead-acid batteries are still used in these types of vehicles. They do not require complex systems of performance management and monitoring and are easy to maintaining. Despite the basic disadvantage, which is the low value of energy density, low price is a decisive factor for their use in low-speed electric vehicles. The process of aging of the battery related with an increase in internal resistance of the cells and the loss of electric capacity of the battery was considered. A simplified model of cooperation of the DC electric motor with the battery assuming increased internal resistance was presented. In the paper the results of comparative traction research of the light-duty vehicle equipped with a set of new batteries and set of batteries having a significant degradation level were showed. The analysis of obtained results showed that the correct exploitation of the battery can slow down the processes of degradation and, thus, extend battery life cycle.

Design and Investigation on Soft-Packed Sodium-Ion Batteries Based on Layered Sodium Transition Metal Oxide Cathodes

Sodium ion battery (SIB) technology is considered as an attractive alternative to lithium ion batteries for the large scale energy storage systems due to vast availability of sodium resource. Up to now, much research effort has been devoted to the exploration of advanced electrode materials for SIBs. In order to promote the industrialization of sodium ion batteries, we scale up the synthesis of layered oxides NaxMO2 (M: Fe, Mn, Ni, Cu, Ti) using facile hydroxide co-precipitation combined with following calcination method. The obtained cathode materials showed good rate performance and excellent cycling stability even at low temperature. The Nax(Fe0.5Mn0.5)O2 cathode showed excellent reversibility between 2.0 V and 4.0 V with reversible capacity of 100 mAh g-1 (0.1 C). After Ni doping, the Nax(Fe0.5Ni0.3Mn0.2)O2 cathode showed good rate performance and excellent cycling stability with an initial capacity of 130 mAh g-1 at 1C. When hard carbon was used as anode, we designed soft-packed batteries with capacities ranging from 0.5Ah to 5Ah. Electrochemical behaviors of the batteries at different temperatures were studied and thermal stability of these batteries was also evaluated. A 0.1KWh sodium ion battery pack was fabricated and evaluated as shown in Fig.1. The sodium ion packs can be assembled and used in portable energy storage device, household electrical energy storage, smart grid and low-speed electric vehicle, etc. The authors are grateful for the financial support of this work by the Natural Science Foundation of China (21573147, 21506123, 21336003) and the 973 Program of China (2014CB239700). Figure 1

A Viability Study of a Lithium Battery Powered Golf Cart

AbstractThere is a recent trend among low speed electric vehicle manufacturers to update traction batteries from older, heavy chemistries to new, lighter battery chemistries. In this viability study, a Club Car Villager LSV electric golf cart was converted from the original flooded lead acid batteries to hard carbon/mixed oxide lithium batteries. The range and speed of both chemistries are compared. This paper demonstrates a potential operational savings for ight electric vehicle users. Despite a reduction in volume, the lithium batteries outperformed the lead acid in both range (46.7% increase) and charging time (95% reduction). The range increase was due, in part, to a reduction in battery weight of 62.5%. In addition to range test results, implementation of the lithium battery management system and J1772 charger system used to support this conversion are discussed.

Development of the Lower Power Consumption FET-DC Contactor for Golf Cart and Low Speed Electric Vehicle

Development of the Lower Power Consumption FET-DC Contactor for Golf Cart and Low Speed Electric Vehicle

Performance investigation and analysis of market-oriented low-speed electric vehicles in China

Abstract Electric vehicles are thought to be an effective solution to the fossil fuel energy resource crisis and environmental pollution, but a wide gap remains between current market conditions and the anticipated products. Despite this, low-speed electric vehicles have already achieved commercial success in the low-end performance electric vehicle market in China. This paper examines the ride characteristics, dynamic performance, battery performance, and power efficiency of a low-speed electric vehicle. Accurate vehicle characteristics under road ride loads were achieved through dynamometer tests that mimic practical road conditions. The overload performance is tested under drive power demands that approach 4.3 times the rated value. The effects of different batteries on the cost performance of low-speed electric vehicles are also analysed. Although the lithium-ion polymer battery is currently more expensive than the lead-acid battery, the increased efficiency of this battery provides a more economical full-cycle lifetime driving distance for practical applications. Despite the excellent overload capability, the low power efficiency of the DC drive motor and its control system limit the general power efficiency of the low-speed electric vehicle and determine its economical speed. Thus, low-cost, efficient drive systems are required to improve the cost performance of low-speed electric vehicles. Some optimisation methods for improving low-speed electric vehicle performance are suggested. By analysing the factors that influence power efficiency and cost performance, this article provides a baseline for improving low-speed electric vehicle performance and advancing the application of this market-oriented electric vehicle.

저속 전기자동차용 알루미늄 차체 조인트 노드의 반응고 성형

The thixoforming process has been applied to forming of a joint node for the aluminum frame of a low speed electric vehicle. A joint node should connect three aluminum extruded chassis showing different profiles. The MHS(magnetohydrodynamic stirring) A357 billet was selected because homogeneous globular grains are necessary as the billet materials for thixoforming. A careful design of joint node has been performed by the considerations of structural demands and the simulation results for the thixoforming process using the MAGMAsoft. Optimum heating temperature for the A357 billet was between 580 and <TEX>$585^{\circ}C$</TEX> corresponding to the semi-solid temperatures showing 20-30% of liquid fraction. An injection speed of around 100mm/s and preheating of die at temperatures of <TEX>$200^{\circ}C$</TEX> were also necessary conditions to obtain reasonable thixoformed parts.

The Current Dilemma and Future Path of China’s Electric Vehicles

China had set an ambitious development target of electric vehicles (EVs) to mitigate the environmental pollution. However, the actual situation of EVs far lagged behind the goals. This paper analyzes the elements impeding EVs’ development, which are identified into four contributors, including deficient EV subsidy policies, embarrassed EV market, local protectionism, and unmatched charging infrastructure. Based on the actual situation of China, this paper discusses corresponding policy suggestions and explores the alternative roadmap of EVs. In the initial development stage of EVs, it is important to select the appropriate charging mode for EVs according to different characteristics across users. Moreover, the development of hybrid electric vehicle (HEV) may open the EV market faster than battery electric vehicle (BEV). In addition, the low-speed EVs may be a good choice for the rural market and should be well developed. With the promotion of EVs, China central and local governments should make rational policies to promote EVs’ development, which is the crucial force to drive the uptake of EVs.

Characteristics Comparison of a Conventional and Modified Spoke-Type Ferrite Magnet Motor for Traction Drives of Low-Speed Electric Vehicles

Rare-earth magnets have been widely employed for traction drive motors of hybrid and electric vehicles (EVs) due to high energy density. Nevertheless, the magnets have critical problems such as unstable supply and high cost. Recently, in order to solve the problems, a variety of motors not using rare-earth materials have been reviewed, such as an induction motor, a switched reluctance motor, and a spoke-type ferrite magnet motor (FMM). In this paper, a modified spoke-type FMM with a novel rotor configuration was presented for a traction motor of low-speed EVs. The characteristics of the modified spoke-type FMM are numerically compared with a conventional spoke-type FMM at the same design condition. Finally, the modified spoke-type FMM is fabricated and tested in order to verify its performance and feasibility.

China's New Energy Vehicles: Value and Innovation

Purpose: The overarching theme is the importance of innovations that are created within the emerging economies. More specifically, the article looks at the development of various alternatives to vehicles powered by the internal combustion engine, new energy vehicles (NEVs) within China. Design/Methodology/Approach: The broad strategic approach of two sectors within the NEV sector in China, the pure electric vehicle (EV) and the low-speed electric vehicle (LSEV) sectors, are compared using recent data and conclusions are drawn. Findings: The EV sector is viewed by the central government as a key sector for China's future industrial growth and is heavily supported. In contrast, the LSEV sector receives no support from central government and yet clearly outstrips the sales of EVs. The article argues that the latter's success is a reflection of the LSEV sector's focus on business model rather than technological innovation. Practical Implications: The article highlights the importance of monitoring innovations that come from within emerging economies and also illustrates the benefits that can come from commercially focused innovations rather than those based on technology. Social Implications: Finding alternatives to vehicles powered by fossil fuels is one of the most important challenges facing the world today. This article looks at the search for one alternative and examines its implications. What is Original/Of Value?: The article examines a business sector that is peculiarly Chinese and yet has potential implications far beyond China. It also contains recent sales figures and other data collected directly from sources in China.

Net-Shape Forming of a Roof Joint Node by Thixoforming of A357 Aluminum Alloy for a Low Speed Electric Vehicle

In the present study, process developments for net-shape forming of aluminum roof joint node have been described. These joint node parts were designed for low speed electric vehicles of which operating condition is more moderate than general compact cars. Thixoforming of Al-7%Si-0.5%Mg (A357) alloy has been applied to the net-shape forming of a complex roof joint node to support aluminum space frame structure of low speed electric vehicle. Optimum heating temperature for the A357 billet was between 580 and 585°C corresponding to the semi-solid temperatures showing 20-30% of liquid fraction. An injection speed of around 100mm/s and preheating of die at temperatures of 200~250°C were also necessary conditions to obtain reasonable thixoformed parts.

Research on Group Decision Making Model of Low-Speed Pure Electric Vehicle's Technology Integrated Innovation

In this paper, on the basis of previous research on group decision making, it summed up the concept and features of group decision making model of the low-speed pure electric vehicles technology integration innovation; and carried on the detailed elaboration about the elements (objectives, standards, support systems, decision-making body, the object and programs, etc.) of group decision making.

자차 송신기 신호 간섭회피 기능을 갖는 차량의 충돌방지 센서

저속 전기자동차에 사용되는 차량 간 충돌방지 센서의 간섭저감 방법에 대하여 연구하였다. 앞차에서 송신되는 기준신호를 수신하여 앞차와의 거리를 감지하는 차량 충돌방지용 거리센서는 뒤차를 향하여 발신되는 자차의 송신신호에 의해 간섭되는 것을 피하기 위하여 다양한 방법이 시도된 바 있다. 본 연구에서는 자차 송신기에서 발신되는 신호에 의한 영향을 위상소거법을 사용하여 감소시켜 -12dB 의 감쇄 비를 실현하였다. 본 연구에서 시도한 위상소거법은 종래의 시분할 송수신 방법에 비해 연속적인 감시가 가능한 장점이 있다. Interference reduction method of vehicle collision avoidance sensor which is used for the low speed electric vehicle has been investigated. Various methods were attempted for the vehicle collision avoidance distance sensor, which received a transmitted signal from a front driving vehicle to measure the distance between two vehicles, to avoid interference by the own transmitter signal toward the rear following vehicle. In this study, -12dB of interference cancellation ratio was realized by using the phase cancellation method to the transmitted signal from the own vehicle. Proposed phase cancellation method is regarded to have the advantage of continuous monitoring in comparison to the conventional time sharing transmitting and receiving method.

China's new energy vehicles: value and innovation

PurposeThe overarching theme of this article is the importance of innovations that are created within the emerging economies. More specifically, the article aims to focus on the development of various alternatives to vehicles powered by the internal combustion engine, new energy vehicles (NEVs), within China.Design/methodology/approachThe broad strategic approach of two sectors within the NEV sector in China, the pure electric vehicle (EV) and the low‐speed electric vehicle (LSEV) sectors, are compared using recent data and conclusions are drawn.FindingsThe EV sector is viewed by central government as a key sector for China's future industrial growth and is heavily supported. In contrast, the LSEV sector receives no support from central government and yet clearly outstrips the sales of EVs. The article argues that the latter's success is a reflection of the LSEV sector's focus on business model rather than technological innovation.Practical implicationsThe article highlights the importance of monitoring innovations that come from within emerging economies and also illustrates the benefits that can come from commercially focused innovations rather than those based on technology.Social implicationsFinding alternatives to vehicles powered by fossil fuels is one of the most important challenges facing the world today. This article looks at the search for one alternative and examines its implications.Originality/valueThe article examines a business sector that is peculiarly Chinese and yet has potential implications far beyond China. It also contains recent sales figures and other data collected directly from sources in China.

Business ecosystem extension: facilitating the technology substitution

This paper studies how the technological ecosystem extension facilitates the technology substitution in an emerging industry. Specifically, this paper has three findings: 1) the technological ecosystem with an expanded scope including supply, demand and intermediaries; 2) two type of ecosystem extension as the bottom-up and top-down ecosystem extension; 3) the determinants of sustaining the ecosystem extension. We have conducted in-depth interviews in the Chinese low-speed electric vehicle industry, which adopted the bottom-up ecosystem extension by comparing with the traditional car industry with top-down ecosystem extension to the emerging EV industry. This paper also offers managerial implications to the focal firms and policy makers to capture the emerging opportunities within an ecosystem.

Impacts of low-speed vehicles on transportation infrastructure and safety

There are increasing numbers of low-speed electric vehicles (LSV) on public roadways. These vehicles are designed to be used within protected environments and on roadways with a maximum posted speed of 25 mph. Currently these vehicles are not subject to the same federal requirements for occupant protection as passenger cars. The research reported in the paper investigated safety standards, operating regulations, and LSV manufacturer materials from sources around the world. The purpose of the research was to determine positive and negative impacts that LSV, including Neighborhood Electric Vehicles (NEVs) and Medium Speed Electric Vehicles (MSEVs), are likely to have for the states such as Oregon, and whether adjustments in state regulations are needed to ensure that LSV do not negatively impact road safety and traffic operations, or expose the LSV operators to undue risk. The U.S. and Canadian federal motor vehicle safety agencies have harmonized their regulations and stipulated the maximum operating speed of these vehicles, however state and local roadway authorities have regulated the maximum speed of roadways and intersection characteristics on which these vehicles can operate. The significant recommendations of this research are: (i) appropriate state statues for LSV should be amended such that LSV are limited to public roadways with a maximum operating speed of 25 mph, and they are restricted to crossing higher speed roadways at four-way Stop or signal controlled intersections, (ii) local transportation authorities should develop parallel or secondary low-speed roadway networks that connect residential neighborhoods with major activity centers.

Transistors, electric vehicles and leapfrogging in China and Japan

PurposeThe goal of the article is to use the concepts of catching‐up and leapfrogging that are most often found in the literature on developmental economics to explore the process by which newcomers overturn an established market leader.Design/methodology/approachThe article uses two case studies, one of the initial development of the transistor radio by the Japanese and the other of the development of electric vehicles in China, to illustrate the application of these concepts to concrete examples.FindingsThe way in which Sony caught up with, and jumped ahead of, American radio manufacturers is explained using the concepts of catching‐up and leapfrogging to emphasize the different phases in the process. This is contrasted with the development of electric vehicles in China which is a process that is still unfolding. The potential importance of one particular development, the low speed electric vehicle, is highlighted.Practical implicationsThe concepts of catching‐up and leapfrogging provide a simple method to visualize the ways in which a newcomer might overtake an incumbent. Their application to the case studies also highlights the crucial importance of a sound business model in this process.Originality/valueAlthough the case of Sony and the transistor radio is relatively well known, this article places it in a new conceptual framework. The case of the development of electric vehicles in general, and the example of the low speed electric vehicle in particular, is new and has not been widely explored.

저속 전기자동차 제어용 비접촉식 조이스틱 개발

Noncontactable joystick for a low speed electric vehicle(LSEV) is developed. The joystick is proposed to replaced the steering wheel in a conventional LSEV. The main advantages of the proposed joystick are a durable and a stable in structure, simple and easy to control through discriminating the driving and braking area. To reduce error and stability in the joystick control, input and output signal of the joystick are manipulated by data averaging and differntiation. With this algorithm, the driving resolution and capability are improved. To verify the proposed algorithm, a simple prototype model which has two electric motors for propulsion and steering are used. Test results show that the prototype joystick control system is applicable to an LSEV dirve.