Grietus Mulder

Assessment of performance of lithium iron phosphate oxide, nickel manganese cobalt oxide and nickel cobalt aluminum oxide based cells for using in plug-in battery electric vehicle applications

This paper represents a comprehensive comparison of three battery chemistries for use in plug-in battery electric vehicles: lithium iron phosphate oxide, lithium nickel manganese cobalt oxide and nickel cobalt aluminum oxide anodes. The battery characteristics at different temperature conditions have been investigated, using test procedures as defined in the standard IEC 62660–1/2 and introducing new load profiles. Main focus key parameters are the energy density, power capabilities, rate performances during charge and discharge as well as the energy efficiency, thermal behaviour and life cycle. The results indicate that the lithium iron phosphate based cells have good performances at low temperatures (such as down to −18° C). However, the situation regarding the nickel cobalt aluminum oxide and nickel manganese cobalt oxide anodes demonstrates less favorable performances, especially at low temperatures where the power and energy capabilities are considerably poor. In addition, the cycle life properties are discussed in order to evaluate the long-term performances, and battery parameters such as cost and thermal behaviors are compared. Finally, this study contains a new definition for the well-known Peukert relationship during the discharge phase. Furthermore, an adapted equation during the charge phase is presented based on the charge characteristics of the proposed batteries at different environmental conditions.

Evaluation of performance characteristics of various lithium-ion batteries for use in BEV application

The purpose of this paper is to assess the capabilities of commercial lithium-ion batteries for use in battery electric vehicles (BEVs). The evaluation criteria are based on a newly developed experimental methodology which describes the performance characteristics of different batteries of various chemistries. This methodology primarily permits the user to obtain the most important battery characteristics for charging and discharging, internal resistance, efficiency, Peukert constant, thermal stability during charge and discharge phases.

Improving optimal control of grid-connected lithium-ion batteries through more accurate battery and degradation modelling

Abstract The increased deployment of intermittent renewable energy generators opens up opportunities for grid-connected energy storage. Batteries offer significant flexibility but are relatively expensive at present. Battery lifetime is a key factor in the business case, and it depends on usage, but most techno-economic analyses do not account for this. For the first time, this paper quantifies the annual benefits of grid-connected batteries including realistic physical dynamics and nonlinear electrochemical degradation. Three lithium-ion battery models of increasing realism are formulated, and the predicted degradation of each is compared with a large-scale experimental degradation data set (Mat4Bat). A respective improvement in RMS capacity prediction error from 11% to 5% is found by increasing the model accuracy. The three models are then used within an optimal control algorithm to perform price arbitrage over one year, including degradation. Results show that the revenue can be increased substantially while degradation can be reduced by using more realistic models. The estimated best case profit using a sophisticated model is a 175% improvement compared with the simplest model. This illustrates that using a simplistic battery model in a techno-economic assessment of grid-connected batteries might substantially underestimate the business case and lead to erroneous conclusions.

Comparative study of different multilevel DC/DC converter topologies for second-life battery applications

This paper is part of a research project, which aims to investigate the possibilities of using the second life batteries after their replacement from plug-in electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and battery electric vehicles (EVs) for smart grid applications. Batteries which are used for vehicular service cannot be used once that the capacity becomes less than 70%-80% [1]. The remaining capacity of the battery can be utilized for stationary applications during peak load hours and to reduce the environmental pollution. These batteries are defined as second life batteries. In these applications, the power electronic converters (PECs) play an important role in the development of high performance integrated systems. It means that the performance of the second life batteries mainly depends on the characteristics of the PECs, which are utilized to achieve the integration of the second life batteries with the smart grid. Therefore, this paper represents a comparative evaluation of different multilevel DC/DC converter topologies that can be used to connect the second life batteries to smart grid. Furthermore, the advantages and drawbacks of the most popular multilevel DC/DC converter (MLDC) topologies are presented in detail. In this paper, a selected harmonic elimination (SHE) technique has been used to realize the control system of the multilevel DC/DC converter, and its influence on the performance of each battery module is analyzed. These topologies are designed and verified by using MATLAB/Simulink environment.

Influence of selective harmonic elimination technique of Multi-Level DC/DC converter on second-life battery performances

This paper is part of a research project, which aims to investigate the possibilities of using the second life batteries after their replacement from the plug-in electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and battery electric vehicles (EVs) for smart grid applications. In these applications, the power electronics converters (PECs) play a key role in the development of a high performance integrated system. This paper shows that the performance of the batteries will be affected by the performance of the PECs, which are utilized to achieve the integration of the batteries with the smart grid. Therefore, this paper demonstrates the impact of the Multi-Level DC/DC Converter (MLDC) on the performances of the battery system. The Selected Harmonic Elimination (SHE) technique is used to realize the control system of the Multi-Level DC/DC Converter (MLDC). In addition, the battery model of a Lithium-ion iron phosphate (LFP) with different capacities (7Ah, 14Ah and 20Ah) is used to investigate the impact of the switching angles and the voltage levels of each module on the performance of each battery module. This system (including the battery modules, MLDC and electric load) is designed and verified by using MATLAB/Simulink environment. Furthermore, this paper provide an extended analysis to select the proper switching angles for different units of MLDC, which can be used for both of designing the control strategy of second life battery and achieving less Total Harmonic Distortion (THD) at AC side.