Low-speed Electric Vehicles Research Articles

A two-pronged approach:Bulk-phase substitution and second-phase synergism to enhance the anion redox stability of layered oxide cathode for sodium-ion batteries

As a supplement to lithium-ion batteries, sodium-ion batteries have great application potential in large-scale energy storage equipment, vehicle start-stop power supplies, and low-speed electric vehicle power. P3-NaxLiyMn1-yO2 (NLMO), has received widespread attention due to its higher charge voltage and discharge capacity. However, poor cycle stability and rapid voltage platform decay caused by the release of oxygen during charging hinder its practical application. This paper reports a new NLMO modification strategy, which effectively improves the cycling stability of NLMO by substituting Zr4+ for Mn4+ in the bulk phase to suppress the O2−/On− redox couple activity and stabilize the ZrO2 second phase lattice. Under the combined action of substitution and second phase, the capacity retention rate of NLMO@Zr0.15 was 85.4 % after 100 cycles at a rate of 5 C. The results show that Zr4+ changes the coordination environment and electronic structure of O in the crystal lattice, prompting further splitting of Mn t2 g, thereby increasing the proportion of Mn 3d orbitals near the Fermi level. During the first discharge process, due to the charge balancing effect, Mn3+/Mn4+ replaced the electrochemical activity of O2−/On−, obtaining a specific capacity of up to 161 mAh g−1. This internal and external improvement idea provides a new direction for solving the poor cycle stability of NLMO high specific energy sodium-ion battery cathode materials and improving the specific capacity.

Community Public Mobility Using On-Demand, Low-Speed Electric Vehicles: A Case Study in Downtown St. Louis, Missouri

Legacy fixed-route transit systems designed to serve commuters struggle to provide efficient and effective service for short neighborhood trips and for population groups unable to access and egress transit stops using active modes (e.g., elderly, disabled). Neighborhood on-demand transit (ODT) services using low-speed electric vehicles (LSEVs) are an innovative technological solution that could help fill this gap in service (e.g., short, high-frequency trips) for diverse populations and trip types. This study evaluated user characteristics and travel behavior for a neighborhood ODT service (using LSEVs) in downtown St. Louis, MO, using responses from a community survey ( n = 244), ridership data, and vehicle trajectory information. A comparative analysis between neighborhood ODT, fixed-route transit, and transportation network companies (TNCs) was also conducted from the perspectives of total travel time, cost, and greenhouse gas emissions. Ultimately, the goal of the analysis was to motivate and inform holistic public mobility systems where different services are optimized to meet specific community needs. Findings indicate that the neighborhood ODT was effective at reaching diverse populations (elderly [20%], lower income [27%], and households with limited access to private vehicles [34%]). ODT reduced total travel time by 32% compared with fixed-route transit, produced 2.4 to 4.3 times less greenhouse gas emissions per passenger mile (compared with transit and TNCs), and was more affordable (free to users) than alternative options ($1 for transit, $10 to $12 for TNCs). Overall satisfaction rates were high, with 80% of respondents rating the service a 4 or 5 out of 5.

From Lab to Application: Challenges and Opportunities in Achieving Fast Charging with Polyanionic Cathodes for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs), recognized for balanced energy density and cost-effectiveness, are positioned as a promising complement to lithium-ion batteries (LIBs) and a substitute for lead-acid batteries, particularly in low-speed electric vehicles and large-scale energy storage. Despite their extensive potential, concerns about range anxiety due to lower energy density underscore the importance of fast-charging technologies, which drives the exploration of high-rate electrode materials. Polyanionic cathode materials are emerging as promising candidates in this regard. However, their intrinsic limitation in electronic conductivity poses challenges for synchronized electron and ion transport, hindering their suitability for fast-charging applications. This review provides a comprehensive analysis of sodium ion migration during charging/discharging, highlighting it as a critical rate-limiting step for fast charging. By delving into intrinsic dynamics, key factors that constrain fast-charging characteristics are identified and summarized. Innovative modification routes are then introduced, with a focus on shortening migration paths and increasing diffusion coefficients, providing detailed insights into feasible strategies. Moreover, the discussion extends beyond half cells to full cells, addressing challenges and opportunities in transitioning polyanionic materials from the laboratory to practical applications. This review aims to offer valuable insights into the development of high-rate polyanionic cathodes, acknowledging their pivotal role in advancing fast-charging SIBs.

Hybrid battery energy storage for light electric vehicle — From lab to real life operation tests

The aim of the research presented in the paper is to improve the lifetime of lead-acid battery systems which are widely used in low-speed electric vehicles or utility vehicles, since the cycle life of lead-acid batteries is nonlinearly dependent on the depth of discharge and electrolyte temperature. The solution proposed here is to connect lead-acid batteries with a small lithium‑iron-phosphate battery using only a diode. This connection is simple and does not require the use of an actively controlled converter. The concept was tested at various levels of an experiment, from the initial calculation of cycle life improvement and simulation, through a laboratory experiment, all the way to operational environment tests. The results obtained confirmed the main assumptions of the study: decrease in the depth of discharge of lead-acid battery for the distance traveled of around 17 %—which would translate into a 30 % better cycle life according to the characteristics indicated by the producers—and decrease in the root mean square and maximum current values of lead-acid battery by around 40–50 % and 26 %, respectively. Range extension was also achieved in vehicles. The solution has been successfully introduced to the market and is now used in few light electric vehicles.

Low-stiffness comfort shift characteristics of a permanent magnet two-speed transmission for low-speed EV

Jerk during shift in mechanical two-speed transmissions often have a serious impact on driving comfort. Within this paper, a proposed two-speed permanent magnet transmission is presented for low-speed electric vehicles, which utilizes magnetic non-contact transmission. This transmission is composed of a magnetic drive mechanism, a clutch, and a selectable one-way clutch. Then, a mathematical model is established for the magnetic-machine composite transmission based on the principles of magnetic field modulation and the concentrated parameter method. Additionally, a shift method that operates without power interruption is presented. Finally, the process of shifting is simulated for permanent magnet drive systems with varying magnetic coupling stiffness in a MATLAB/Simulink environment. The resulting torque calculations are compared with those obtained from the commercial software Maxwell. Simulation results indicate that the two-speed permanent magnet transmission does not experience power interruption during upshifting. Less jerk when shifting gears. Low magnetic coupling stiffness can reduce high-frequency vibration and enhance shift comfort. The findings from the torque calculations obtained through the proposed model align with those obtained from the commercial software Maxwell.

Improvement of cycle life for layered oxide cathodes in sodium-ion batteries

In this review, research progress on layered oxide cathodes for SIBs in recent years is summarized, with emphasis on the problems of poor cycle life caused by irreversible phase transition, Jahn–Teller effect and interface deterioration, and several strategies are proposed to alleviate these issues.

High-Efficiency Separator Capacity-Compensation Strategy Applied to Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are expected to replace partial reliance on lithium-ion batteries (LIBs) in the field of large-scale energy storage as well as low-speed electric vehicles due to the abundance, wide distribution, and easy availability of sodium metal. Unfortunately, a certain amount of sodium ions are irreversibly trapped in the solid electrolyte interface (SEI) layer during the initial charging process, causing the initial capacity loss (ICL) of the SIBs. A separator capacity-compensation strategy is proposed, where the capacity compensator on the separator oxidizes below the high cut-off voltage of the cathode to provide additional sodium ions. This strategy shows attractive advantages, including adaptability to current production processes, no impairment of cell long-cycle life, controlled pre-sodiation degree, and strategy universality. The separator capacity-compensation strategy is applied in the NaNi1/3 Fe1/3 Mn1/3 O2 (NMFO)||HC full cell and achieve a compensated capacity ratio of 18.2%. In the Na3 V2 (PO4 )3 (NVP)||HC full cell, the initial reversible specific capacity is increased from 61.0 mAh g-1 to 83.1 mAh g-1 . The separator capacity-compensation strategy is proven to be universal and provides a new perspective to enhance the energy density of SIBs.

Human–Machine Redundant Braking System for Aftermarket Low-Speed Electric Vehicle: Design and Validation

This paper presents the design and experimental validation of a novel human–machine redundant braking system (HMRBS) for aftermarket low-speed electric vehicles (LSEVs) to realise the backup redundancy ability and improve active safety. First, the HMRBS is designed by connecting the electro-hydraulic braking (EHB) unit oil pipelines in parallel with the manual braking (MB) unit through two three-way shuttle valves. Then, the mathematical model of the EHB subsystem is built, and a master cylinder pressure controller with adaptive fuzzy proportion integration differentiation (PID) and a servo motor speed controller with double-closed-loop proportion integration (PI) are proposed to improve the system response performance. Following this, the co-simulation model of the proposed closed-loop system is established based on AMESim and MATLAB/Simulink to validate the feasibility of the proposed control strategy. Finally, the effectiveness of the HMRBS is also validated by test rig and vehicle experiments. The results imply that the modified LSEV with the HMRBS meets the requirements of vehicle active braking ability and manual braking redundancy. Furthermore, the proposed controller can significantly enhance pressure control accuracy compared to the classical PID controller. The deceleration fluctuation and braking distance in the active braking mode are smaller than those in the manual braking mode, indicating that the proposed system makes the braking effect more stable and safer.

A thermodynamically stable O2-type cathode with reversible O2-P2 phase transition for advanced sodium-ion batteries

Low-cost sodium-ion batteries (SIBs) have shown very promise in the applications of renewable energy and low-speed electric vehicles. The development of a new O2-type cathode in SIBs is very challenging in that this compound is only stable as an intermediate product of P2-type oxides during redox reactions. Here, we report a thermodynamically stable O2-type cathode obtained by Na/Li ion exchange from P2-type oxide in a binary molten salt system. It is demonstrated that the as-prepared O2-type cathode exhibits a highly reversible O2–P2 phase transition during Na+ de-intercalation. The unusual O2–P2 transition has a low volume change of ∼11%, much lower than that of 23.2% for P2–O2 transformation in the P2-type cathode. The lowered lattice volume change of this O2-type cathode gives rise to superior structural stability upon cycling. Therefore, the O2-type cathode possesses a reversible capacity of about 100 mAh/g with a good capacity retention of 87.3% even after 300 cycles at 1C, indicating outstanding long-term cycling stability. These achievements will promote the development new class of cathode materials with high capacity and structural stability for advanced SIBs.

A Novel Simplified Model of Dual Motor Belt Drive for Modern Motorcycles and Low Speed Electric Vehicles

A Novel Simplified Model of Dual Motor Belt Drive for Modern Motorcycles and Low Speed Electric Vehicles

Ti, F Codoped Sodium Manganate of Layered P2-Na 0.7 MnO 2.05 Cathode for High Capacity and Long-Life Sodium-Ion Battery

Ti, F Codoped Sodium Manganate of Layered P2-Na _0.7 MnO _2.05 Cathode for High Capacity and Long-Life Sodium-Ion Battery

Design Strategies for High-Energy-Density Aqueous Zinc Batteries.

In recent years, the increasing demand for high-capacity and safe energy storage has focused attention on zinc batteries featuring high voltage, high capacity, or both. Despite extensive research progress, achieving high-energy-density zinc batteries remains challenging and requires the synergistic regulation of multiple factors including reaction mechanisms, electrodes, and electrolytes. In this Review, we comprehensively summarize the rational design strategies of high-energy-density zinc batteries and critically analyze the positive effects and potential issues of these strategies in optimizing the electrochemistry, cathode materials, electrolytes, and device architecture. Finally, the challenges and perspectives for the further development of high-energy-density zinc batteries are outlined to guide research towards new-generation batteries for household appliances, low-speed electric vehicles, and large-scale energy storage systems.

A facile synthesis of CuSe nanosheets for high-performance sodium-ion hybrid capacitors.

Due to the low price and abundant reserves of sodium resources, sodium-ion batteries have become the main candidate for the next generation of energy storage equipment, particularly for large-scale grid storage and low-speed electric vehicles. Transition metal selenides have attracted considerable attention because of their high reversible capacity, superior electrical conductivity and versatile structures. In this study, two-dimensional CuSe nanosheets are synthesized via a simple hydrothermal reaction. When acting as an electrode material for sodium-ion batteries, the CuSe electrode exhibits an initial coulombic efficiency of 96.7% at a current density of 0.1 A g−1 and a specific capacity of 330 mA h g−1 after 100 operation cycles, as well as retains a specific capacity of 211 mA h g−1 even at a high current density of 10 A g−1. Moreover, the anode delivers a specific capacity of 236 mA h g−1 after 3300 cycles at 5 A g−1 with a capacity retention of 91.2%. In sodium-ion hybrid capacitors (SHICs) with the two-dimensional CuSe nanosheets and Ti3C2Tx MXene as the negative and positive materials, respectively, the nanosheets without any pre-sodiation present a lifespan of up to 2000 cycles at 2 A g−1 and a capacity retention of about 77.7%.

Ultrathin CuSe nanosheets as the anode for sodium ion battery with high rate performance and long cycle life

Sodium-ion batteries (SIBs) have quickly developed to be important alternative energy storage devices other than lithium-ion batteries in the explosively growing market of large-scale grid storage and low-speed electric vehicles, thanks to their low cost and the abundance of sodium resources. However, the sluggish sodiation kinetics remains major concerns in design of competent anode materials for SIBs. Herein, by using a one-step, facile hydrothermal synthesis, well-defined ultrathin CuSe nanosheets (thickness of ∼5 nm) were fabricated, leading to a narrow bandgap, flexible Cu–Se bonding and abundant electrochemically active sites. As a result, the product presents high rate performance: a high capacity of 404 mAh g–1 is achieved at a current density of 0.1 A g–1 after 100 operation cycles, and the capacity can be maintained to 276 mAh g–1 even at a high current density of 20 A g–1. According to kinetics analysis, surface capacitance contributes dominatly in the electrochemical process, facilitating fast sodiation. Moreover, coordinated the ultrathin thickness and two-dimensional morphology of the nanosheets with their three-dimensional open framework, the volume expansion-related issues during charge/discharge processes have been well addressed, resulting in ultrahigh cycling stability (with 100% capacity maintenance after 500 cycles at 0.5 A g–1) together with ultralong cycle life (up to 10,000 working cycles) at 20 A g–1.

Sn4P3-inlaid graphene oxide nanohybrid through low-temperature solid state reactions toward high-performance anode for sodium-ion batteries

Due to nature abundant and low-cost of sodium reserves with broad distribution in the earth's crust, sodium-ion batteries (SIBs) have attracted widespread attention for their great potential application in low-speed electric vehicles and large-scale energy storage system. However, their practical application is still hampered by the lack of decent anode materials. In this work, we develop an effective strategy to fabricate a nanohybrid of Sn4P3 and graphene oxide and demonstrate its outstanding sodium-storage behavior as an anode material for SIBs. By directly grinding tin(IV) chloride pentahydrate, sodium hydroxide, graphene oxide (GO) and surfactant PEG-200 at ambient temperature, an effective solid state reaction occurred to give rise to a precursor (named as SnO2/GO-PEG200), i.e. a nanocomposite of SnO2 encapsulated within GO matrix. After subsequent phosphorization at 280 °C using sodium hypophosphite monohydrate as phosphorous source, a nanohybrid of Sn4P3 and graphene oxide (designated as Sn4P3/GO-PEG200) was acquired. The coexistence of Sn4P3 nanoparticles and GO nanosheets endows the nanohybrid with improved electronic conductivity, highly structural integrity and superior electrochemical performance. When employed as anode material for SIBs, the nanohybrid anode demonstrates a good cycling stability (419 mA h g−1 after 100 cycles at 0.1 A g−1), with a remarkable rate capabilities (325 mA h g−1 at a current density of 1 A g−1 and 187 mA h g−1 at a current density of 5 A g−1, respectively).

Development of Modular DC-DC Converters for Low-Speed Electric Vehicles Fast Chargers

To increase the utilization of Low-Speed Electric Vehicles (LS-EVs), rapid recharging of the EV’s battery pack turn out to be essential. This permits reduced charging times, greater vehicle utility, and broader adoption of LS-EVs. This paper presents a modular Input-Series Output-Parallel (ISOP) DC-DC converter for LS-EVs fast chargers. A generalized small-signal analysis applicable for any multimodule connection (Input-Series Input-Parallel Output-Series Output-Parallel (ISIP-OSOP) is introduced. The employed topology is a multimodule DC-DC converter based on Dual Active Bridge (DAB). Nonetheless, a single bridge is utilized at the primary side, and the modularity concept is applied to the high-frequency transformer and the second bridge where the connection of the modules is ISOP. In the presented system, 3-modules are employed where each module is rated at 1.5kWto achieve the desired power rating, which is 4.5kW. The charging process is achieved from a single-phase outlet. However, due to the high output current, a modular approach is required to avoid high losses. Uniform power-sharing is achieved through a direct output current sharing control, ensuring stability without the need for input voltage sharing loops, unlike the conventional ISOP converters. This is due to the fact that the proposed configuration uses only a single capacitor at the input side, avoiding the inherent instability problem caused by the output current sharing control. The controller is examined using a 3-module ISOP DC-DC converter, where the controlled current is following the reflex charging algorithm. Simulation results using the Matlab/Simulink platform are provided to elucidate the presented concept considering parameter mismatches, where the input voltage and the output current are equally shared among the three modules.

A comprehensive understanding of the anionic redox chemistry in layered oxide cathodes for sodium-ion batteries

Sodium-ion batteries (SIBs) have demonstrated great application prospects in large-scale energy storage systems and low-speed electric vehicles due to the cost effectiveness and abundant resources. Layered transition-metal oxides are recognized as one of the most attractive sodium-ion storage cathode candidates by virtue of their high compositional diversity, environmental friendliness, ease of synthesis, and promising theoretical capacities. The practicability, however, is still limited by the fact that the energy densities of most Na-storage layered oxide cathodes solely using the conventional cationic redox are not comparable to those of the lithium-ion storage counterparts. Recently, the strategy of activating anionic redox (O2−/O n −) which is popular in Li-rich layered materials has been successfully applied in oxide cathodes of SIBs to promote the energy density to a new level. It is interesting to note that excess Na is not the prerequisite to induce anionic redox in sodium oxides, indicating a new mechanism underlying Na-ion materials. Herein, the latest advances on the anionic redox chemistry in layered oxide cathodes for SIBs, including the fundamental theories, triggering strategies, and applicable cathode materials, are comprehensively reviewed. Moreover, the challenges (mainly O2 release) facing anionic redox are discussed, and the possible remedies are outlined for future developments toward a highly reversible oxygen usage. We believe that this review can provide a valuable guidance for the exploration of high-energy layered oxide cathode materials of SIBs.

Directly Generated Hydrogen to Feed a 2.4 Kw PEM Fuel Cell Stack By Hydrolysis of Nanoporous Aluminum with Pure Water

Jules Verne stated more than 145 years ago that water will be the coal of the future [1]. Indeed, hydrogen, a highly abundant substance on Earth in the form of water, is a promising energy carrier for producing zero-emission electricity upon reaction with oxygen using fuel cell technology. There are still many scientific and engineering challenges that need to be addressed before Jules Verne’s dream can become true, however. Two of these challenges include hydrogen production from water and hydrogen storage. In this talk, I will present our work on direct hydrogen generation by hydrolysis of nanoporous aluminum in pure water to feed a 2.4 kW PEM fuel cell stack, which in turn can be used to power a low speed electric vehicle. The possibility to make nanoporous aluminum from secondary aluminum and the advent of carbon-free primary aluminum from Elysis [2,3] could make hydrogen production by hydrolysis of aluminum with pure water a promising alternative to hydrogen production by electrolysis of water.

Deprecated in policy, abundant in market? The frugal innovation of Chinese low-speed EV industry

In the era of “Industry 4.0”, individualized demand and small batch customization manufacturing will become the trend, which calls for strong capabilities of customer orientation and rapid reaction. In addition to the redesign of smart and autonomous production processes, the market-oriented frugal innovation is a valuable exploration under the framework of “Industry 4.0”. This paper anchors itself at a deprecated policy context to study frugal innovation patterns and their forming mechanisms, which is still a rarely touched area. By selecting as its cases Shifeng, Baoya and Taiqi from the Shandong province, China, this paper uses a qualitative approach to analyze low-speed electric vehicle (EV) businesses according to a three-dimension frugal innovation framework composed by business ecosystem (BE) configurations, BE capabilities and innovation process. The findings are as follows, (1) there are three typical frugal innovation patterns, namely market-based persistence, market-based contingency and technology-based contingency, which help frugal innovators obtain an abundant market performance even under a deprecated policy environment; (2) a vertical integration network and strong marketing capabilities are the capital to select a market-based persistence pattern, while the lack of some substantial resources and capabilities compels firms to have to adopt a more flexible way of frugal innovation in order to carve out a safe niche. This paper contributes to frugal innovation research by exploring a new deprecated policy context rather than traditional institution voids, constructing a frugal innovation framework from the BE perspective by focusing on focal firms, and proposing three frugal innovation patterns under different resource constraints. From the practical side, this paper suggests that future innovation policy should balance advanced technology requirements and practical market demands, and the governments should also emphasize market positioning and demand orientation in the process of Industry 4.0 transformation.

The long tail thesis

PurposeThis paper aims to explore the functionality of long tail markets (LTM), where the consumers cannot be reached or are ignored by the traditional mainstream businesses, in new products and business development.Design/methodology/approachFirst, the authors review two Chinese entrepreneurial practices in the Fintech sector and low-speed electric vehicles (LSEV) and describe their stylized facts; second, they explore a possible theoretical LTM framework to underscore these practices; third, they make a connection between LTM and existing business models and analyze its significance and practical implications in business, in particular, in developing economies.FindingsThe LTM business approach has helped Chinese companies in the Fintech sector and LSEVs gain global attention. The success factors of LTM for businesses are identifying a specific customer base, being aware of localization products and playing skillfully with regulations; the LTM approach has several overlaps with existing studies on niche products and base of the pyramid market.Originality/valueBased on some emerging and attractive business practices in China, this paper offers a valuable attempt to theorize them as long tail phenomenon. The LTM thesis provides a potential framework to reference for similar methods elsewhere and may illuminate entrepreneurship to be explored in similar markets.