Shovon Goutam

Development of a Two-Dimensional-Thermal Model of Three Battery Chemistries

The growing need for accurate estimation of by fitting batterys thermal and electrical performances at different operating conditions is crucial in its applications especially in electrified vehicles. This paper presents an effective method for developing a thermal and electrical modeling methodology for calculation thermal behavior of a lithium-ion cell and the voltage response under a current solicitation. The model was elaborated on three pouch cells with different battery chemistries for use in electrical vehicles/hybrid electrical vehicles, namely lithium iron phosphate, lithium nickel manganese cobalt oxide, and lithium titanium oxide (LTO). The model, implemented in a MATLAB/Simulink interface, uses an equivalent circuit and heat-generation equations coupled a thermal model. The three cell chemistries have been investigated using test procedures and thermal images at room temperature. The results of this study show that a temperature distribution to be fairly uniform after a complete discharge for the three chemistries with the lowest temperature gradient found for the LTO-based cell. Finally, comparison between simulation results and measured data under dynamic profiles shows a good correspondence with the measurements of the validation tests with errors lying between ±4% and 2 °C for the electrical and thermal model, respectively.

Batteries 2020 – Lithium - ion battery first and second life ageing, validated battery models, lifetime modelling and ageing assessment of thermal parameters

The European Project “Batteries 2020” unites nine partners jointly working on research and the development of competitive European automotive batteries. The project aims at increasing both the energy density and lifetime of large format pouch lithium-ion batteries towards the goals targeted for automotive batteries (250 Wh/kg at cell level, over 4000 cycles at 80% depth of discharge). Three parallel strategies are followed in order to achieve those targets: (i) Highly focused materials development; two improved generations of NMC cathode materials allows to improve the performance, stability and cyclability of state of the art battery cells. (ii) Better understanding of the ageing phenomena; a robust and realistic testing methodology has been developed and was carried out. Combined accelerated, real driving cycle tests, real field data, post-mortem analysis, modelling and validation with real driving profiles was used to obtain a thorough understanding of the degradation processes occurring in the battery cells. (iii) Reduction of battery cost; a way to reduce costs, increase battery residual value and improve sustainability is to consider second life uses of batteries used in electric vehicle application. These batteries are still operational and suitable to less restrictive conditions, such as those for stationary and renewable energy application. Therefore, possible second life opportunities have been identified and further assessed. In this paper, the main ageing effects of lithium ion batteries are explained. Next, an overview of different validated battery models will be discussed. Finally, a methodology for assessing the performance of the battery cells in a second life application is presented.

Evaluation of lithium-ion battery second life performance and degradation

Reusing electric vehicle batteries once they have been retired from the automotive application is stated as one of the possible solutions to reduce electric vehicle costs. Many publications in the literature have analyzed the economic viability of such a solution, and some car manufacturers have recently started running several projects to demonstrate the technical viability of the so-called battery second life. Nevertheless, the performance and degradation of second life batteries remain an unknown topic and one of the biggest gaps in the literature. The present work aims at evaluating the effects of lithium-ion (Li-ion) battery State of Health (SOH) and ageing history over the second life performance on two different applications: a residential demand management application and a power smoothing renewable integration application. The performance and degradation of second life batteries are assessed both at the cell level and at stack level. Homogeneous and heterogeneous stacks are analyzed in order to evaluate the impact of cell-to-cell history and SOH differences over the stack level battery cell performance and degradation behaviour.

Review of Nanotechnology for Anode Materials in Batteries

Anode, one of the crucial components in a battery cell, equally influences the overall performance of the cell. Versatile applications of batteries and the challenging demand of high-performance batteries have led the research beyond commercial graphite anodes. A significant number of studies have focused on developing high performance anodes. Nanotechnology has evidently been provided a solution to many technical issues in achieving high-performance anodes. In this chapter, a comprehensive review was presented highlighting the recent developments in nanotechnology for anode materials for Li-ion, Na-ion, and Li–S battery technologies. In the first section, a summary is given on the properties of a high-performance anode, followed by the benefits of nanostructured anodes. Two major aspects of nanostructured anodes, the geometrical aspects and the materials, are described separately. In the geometrical aspects, 0D, 1D, 2D, and 3D structures are discussed, highlighting their beneficial and detrimental influences on overall performance. In the material sections, recent developments in different nanomaterials (carbon-based, Si, metal alloys, metal oxides, metal sulfide, and phosphide) were summarized. Different nanomaterials exhibit unique beneficial characteristics but also possess limitations. How compositing one material with others along with hybrid structures (combination of different dimensional structures) can overcome the limitations is also discussed. Finally, limitations of nanotechnology from the perspective of practical implementation and industrial production were summarized.