Reconfigurable battery System Topology, Operation and Feature: A Comprehensive Survey

In traditional battery systems, a large number of battery cells are usually connected in series and parallel with a fixed topology during operation to supply the desired voltage and current. However, this fixed configuration has low reliability, low fault tolerance, and voltage imbalance issue. This paper proposes a new modular and reconfigurable battery pack (MRBP) consisting of reconfigurable battery modules (RBMs) and an H-bridge converter. All the RBMs in the MRBP are cascaded to generate a stepped positive voltage waveform; and the H-bridge is used to change the polarity of the stepped voltage to form a multilevel AC voltage. Multiple MRBPs can be used to form a multiphase modular and reconfigurable battery system (MRBS). High reliability and fault-tolerance capability are achieved due to the modular and reconfigurable features. The state of charge (SOC) balance among battery cells can be easily realized by dynamically configuring the connections of battery cells. A three-phase MRBS prototype is simulated and constructed using the proposed design. Simulation and experimental results are provided to verify the proposed MRBS.

To manage thousands of battery cells effectively, a reconfigurable battery system has emerged where each battery cell is equipped with a set of switches for controlling connectivity (i.e. series, parallel, bypass or combinations thereof). While most studies have focused on maximising operation‐time or life‐time of a reconfigurable battery system, few studies have addressed how to quickly balance voltage of cells, which affects both efficiency and safety of a battery system. A new discharge scheduling policy for battery cell voltage balancing for a reconfigurable battery system is proposed. Based on the analysis why existing naive approaches are not effective for voltage balancing, a new approach consisting of three steps is designed: determination of a set of battery cells to be discharged, calculation of a target voltage, and distribution of the system load to each battery. The present simulation results show that the proposed approach outperforms three alternative ones up to 45.6% in terms of voltage balancing.

This paper proposes a new scalable and reconfigurable battery pack (SRBP), which consists of reconfigurable battery modules (RBMs) and a buffer inductor. Two SRBPs are then connected in series to form a single phase of a multiphase scalable and reconfigurable battery system (SRBS). The SRBS has a flexible interface with external systems with an adjustable DC or a multilevel AC voltage output and is capable of bidirectional DC-AC and DC-DC operations. High reliability and fault-tolerance capability are achieved due to the reconfigurable feature. The state of charge (SOC) equalization among battery cells/modules can be easily achieved by dynamically configuring the connections of battery cells/modules. A three-phase SRBS prototype is simulated and built using the proposed design. Simulation and experimental results on the prototype are provided to validate the proposed SRBS.

This paper deals with a new approach to the reconfiguration of enterprise information system based on object-based knowledge mesh (OKM). To this end, new concepts of OKM is given as well as its multiple sets and reconfiguration operations. Then based on a new OKM & AM-based approach to knowledge representation for enterprise information systems and the reconfiguration operations, the reconfiguration approach is proposed. In addition, the mapping between the enterprise information system and OKMs is explored in detail. Finally the reconfiguration approach is exemplified by the reconfiguration of ERP software used in a plant, which shows the method to be effective.

The efficiency and safety issues caused by cell differences are the key factor to hinder the use of retired batteries. The reconfigurable battery technique is an effective method to break through the bottleneck. However, the potential short-circuit paths increase exponentially with the number of cells, which makes manual analysis unapplicable and brings serious risks in large scale reconfigurable battery systems. Existing researches are about topology and energy efficiency optimization, but the problem of short circuit is ignored. In this article, a systematic approach based on the sneak circuit theory is proposed to fundamentally avoid the short-circuit problem of reconfigurable battery systems. A novel sneak circuit theory based approach is creating a short circuit path table, which will be indexed to avoid connecting the anode and cathode of a battery cell/string. In addition, all the paths are further studied and analyzed, and the simplest path table can be obtained to improve the energy efficiency. To validate the theoretical foundation and feasibility of proposed approach, a reconfigurable battery system containing two kinds of batteries is developed. All experimental results well verify the effectiveness and feasibility of proposed approach. This work provides theoretical foundation for avoiding short-circuit paths in reconfigurable battery systems, which will break through the bottleneck in scale application.

Reconfiguration, a new technique to realize fault-tolerance and respond to changes in external environment, has been adopted in the design of Integrated Modular Avionics (IMA). The benefits brought to the system include: reducing the cost of hardware redundancy and improving system's ability to perform various tasks under different situations. The complexity of such reconfigurable system has made it difficult to ensure the safety of it. Traditional analysis approaches mainly focus on single component failure, suffering the potential to underestimate the influence of design flaw during system development and the interaction between components (e.g. human and automation). Furthermore, dynamic changes brought out by reconfiguration might affect not only the human operator, but also the organization in which the system developed. In this paper, an approach has been proposed to address the problem of safety of Avionics reconfiguration. System-Theoretic Process Analysis (STPA) has been used to perform hazard analysis. Focusing on the coordination between human operator and automation, we define two criteria which could be applied to decide autonomy level: 1) Failure Degree; 2) Time budget for mode change scenario. Furthermore, to identify the impact of dynamic changes to the safety of Avionics reconfiguration, System dynamics modeling has been taken to analyze and model the human factors (mental workload, situation awareness and complacency) behind the dynamic process. The analysis results could be used during system development, system operation and project revision process to ensure safety of reconfigurable Avionics system.

Batteries are interconnected in series and/or parallel to meet wide-range power or energy demands in various industrial applications. To pursue the benefits of multiple connection structures in one system, reconfigurable battery systems (RBSs) have recently emerged for safe and efficient operation, extended energy storage, delivery, etc. Switches are the essential elements to enable the battery system reconfiguration, but selecting appropriate switches for RBS designs has not been systematically investigated. To bridge this gap, analytical expressions are derived in this article to estimate the maximum switch current and its upper limit to facilitate the selection of RBS switches. An RBS prototype based on H-bridges is set up and experimental results verify the effectiveness and advantage of the proposed estimation method. These analytical expressions, relying only on resistances of batteries and switches, are readily applicable to practical RBS design and much more efficient than conducting numerous circuit experiments, simulation tests, or circuit analyses, especially for large-scale systems. Moreover, the analysis framework and estimation method proposed for series–parallel mutual conversion can be adaptively extended to other complex system reconfigurations to facilitate various RBS designs.

Operating systems are constantly getting more complex in the functionality they support, due to the increasing demands made by modem hardware and software innovations. Basing the kernel design on co-operating and modular services incorportating a flexible communications infrastructure with run-time binding makes the operating system dynamically configurable and extensible. These features aid in the management of system complexity, while also resulting in several software engineering and performance benefits. Configurability gives the operating system designer and implementor the freedom to build a large number of components, which can be composed into different configurations depending upon the final system requirements. System components can be built and debugged in a user address space, and then transparently migrated into the kernel address space for performance once they have been demonstrated correct. This removes one of the major obstacles to developing kernel services, that of the necessity to reboot the system after each change to the service code. The system administrator can also reconfigure the system, providing similar advantages, and allowing dynamic system upgrades to be made, reducing system downtime. Extensibility lets new functionality be integrated into the operating system. This can be done on an application specific basis. This enables the development of in-kernel applications in cases where high performance is required, such as for dedicated file servers. It is also possible for applications to interpose specialised kernel services, allowing them to dramatically increase their performance and aggregate system throughput when the default system policies are ill-matched to their behaviour. The Kea operating system has been designed and implemented to be dynamically configurable and extensible. The design of the system features that make these features possible are described. Experimental results are shown that demonstrate that Kea offers comparable performance to a traditional operating system on the same hardware, and that extensibility can be used to increase performance for selected applications.

This study investigates the integration of a modular multilevel inverter-based reconfigurable battery system into an existing electric vehicle. The aim is to evaluate how such systems can replace conventional traction inverters, battery management systems, and on-board chargers. To this end, a classification of the different topology levels and possible forms of integration of power electronics, control logic, and driver electronics is performed. A Tesla Model Y’s traction battery is redesigned, retaining its structural properties and the 4680 cell format. A package analysis shows that the multilevel system occupies a volume comparable to the conventional battery pack, while the volume previously reserved for dedicated power electronics becomes available. Efficiency simulations demonstrate that the multilevel inverter can increase the overall vehicle efficiency, especially in situations with low driving speeds and high torque requirements. As a result, WLTP energy consumption is reduced from 14.9 kWh/100km to 14.5 kWh/100km. However, the battery efficiency is reduced at higher speeds due to higher cell currents. In addition, the system enables bidirectional charging at full system power, including supply to external loads or the grid, and a more integrated vehicle architecture. • Packaging a reconfigurable battery system in a production electric vehicle is possible. • Battery pack volume houses cells and new inverter, freeing up junction box space. • On-board charger can be omitted due to intrinsic high power bidirectional charging. • WLTP energy consumption (excluding charging lossess) is reduced from 14.9 kWh/100 km to 14.5 kWh/100 km. • Inverter losses decrease by up to 76 % at low vehicle speed and high torque.

Objectives: To control the power flow resulting in improved utilization of the available cells, increased lifetime, and higher reliability. Reduce the gross energy demand and global warming potential and to promote Zero Waste.Methods: A reconfigurable battery system using second-life batteries based on cascaded DC-DC converters is presented. When compared to conventional boost converters, it can be demonstrated that each submodule’s power can be controlled separately, improving the battery system’s available capacity. Faulty battery modules can be bypassed, increasing the system’s reliability and fault tolerance capability. The chosen approach is shown with cascaded system using proportional integral derivative (PID) controller and the Single-phase inverter with SPWM technique for the Stationary load applicationFindings: The proposed cascaded system act as a fault tolerant system since the source is the second-life battery even though there is fault has occurred in the system meets the load demand. These simulations are done in MATLAB and the results are discussed. The DC link voltage of the cascaded system has more ripple based on the tuning of the PID controller with the values of Kp,Ki, Kd the ripple can be decreased.Novelty: Cascaded system with a fault-tolerant system using the second life battery will promote the zero-carbon waste of the batter and it is the new approach

Complex systems consist of a large number of entities with their independent local rules and goals, along with their interactions. In the operations of complex system, such as naval ship, proper decisions and controls are required to keep the system working functionally and effectively. An Integrated Reconfigurable Intelligent System (IRIS) framework is proposed for facilitating the design and operation of such naval complex systems through increased automation and reconfigurability. With the reconfigurable systems, the IRIS designed ship will assess the incoming information and then configure itself into the mode most adequate to deal with the situation under consideration. The study in this paper presents a hierarchical control architecture to deal with ever-evolving real time information and making autonomous control for achieving the reconfigurability of naval ship. The control architecture consists of three levels working together to achieve the overall operational goal. It is implemented on a resource allocation problem for a chilled water system. The successful resource allocation leads to a reconfiguration of the system which is the most suitable to handle the situation at hand.

The foundations for building the first Reliable Reconfigurable Real-Time Operating System (R3TOS) are presented. The main objective of R3TOS is to create an infrastructure for coordinately executing specialized hardware tasks upon a reconfigurable FPGA device, achieving the necessary flexibility for both gaining system performance (true hardware multitasking) and tolerating the occurring faults in the underlying chip's silicon at runtime (true fault removal from system). R3TOS is aimed at easing the development of FPGA-based high-performance demanding reliable applications by hiding the complexity of these devices, promoting their use by the whole engineering community.

Transport vehicles require an energy storage system (ESS) with a long lifespan to sustain their energy and power requirements during the start, acceleration, and recapturing of regenerative braking energy. However, a nonintegrated (i.e., single-use) ESS cannot satisfy the requirements of long lifespan, high energy, and power. Hence, a nonisolated direct current-to-direct current (DC-to-DC) bidirectional converter is widely used to integrate the battery and supercapacitor, thus meeting the requirements for vehicle starting, acceleration, and braking energy. Hybrid batteries and supercapacitor energy storage systems (HBSCESSs) are crucial because they preserve the battery lifespan. Supercapacitors handle the high transient currents and power requirements of these systems. However, the performance of HBSCESS depends on the converter configuration. There has been no comprehensive consolidated survey of nonisolated two-way DC-to-DC converters for possible HBSCESS development. It is imperative to compile this coherent analysis to help academia and industry select appropriate converter topologies for HBSCESS development, ideas, and guidance for new possible converters in transport vehicles, DC microgrids, and renewable energy source systems. This study provides an in-depth literature review and classification, assesses whether these converters provide a unified approach for HBSCESS development, and offers feasible solutions for future considerations. In addition, it provides recent research trends and recommendations for developing converters. This study analyzes the available literature on nonisolated converters for HBSCESS development. The analysis shows that multi-input, multi-port, three-port, coupled-inductor, switched-capacitor, and z-source/quasi-z-source converters are suitable for providing a unified hybrid energy storage system (HESS) comprising a battery and supercapacitor. They provide bidirectional power flow in both input ports for applications in transport vehicles, DC microgrids, and renewable energy source systems. The results also show that a single-inductor multi-input converter topology can be used for HBSCESS because it offers simple design, high efficiency, low component count, and moderate duty cycle operation.

The power management system design is a key factor to determine the stability of a sensor nodes-based network environment. In the meanwhile, an application-based resource reconfigurable operating system can enhance the availability, maintainability and flexibility to the required services. In this paper, we propose an integrated power-saving mechanism and reconfigurable approach for the OS design consideration and demonstrate the critical application in farm monitoring and ubiquitous healthcare. To support fast mobile OS porting and implementation, we also propose the on-line retrieval-on-demand design concepts to carry out highly flexible system architecture. Its corresponding applicability in sensor network environment is discussed. The system design cost is evaluated and several simulations for different parameters are conducted and verified.

This paper presents the experimental validation of a lithium-iron phosphate cell model. The modelling of dynamic cell behaviour is crucial to improve the performance of reconfigurable battery systems, in which monitoring of the dynamics allows more resoluted leveraging of the battery cells. However, the models of lithium-ion cells are generally inaccurate due to nonlinearities, measurement noise and because the most descriptive state, the state of charge is hidden. Furthermore, the parameter identification of the model requires time and precise measurements, while they differ among the cells, and change as the cells age. The burden of the detailed modelling of a battery system can be alleviated by modelling a single cell, and using the model for each cell in the system. In this work, this possibility is explored by validating a single-cell reference model for a reconfigurable battery system. The terminal voltage residual (error between model and measurement) is presented, and its correlations with internal and external variables are investigated. These correlations can also be used to alleviate the modelling errors. It is concluded that the reference model can qualitatively describe the cell behaviour. By applying small modifications, the model could be used for online estimation.