Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 2020
This article presents a comparative study between the performances of different energy management... more This article presents a comparative study between the performances of different energy management strategies for hybrid energy storage source supplying electric vehicle. In our case, the hybrid supply is composed of fuel cell as an energy source and lithium-ion batteries as a power buffer. The two storage systems are connected to the DC bus via DC/DC boost converters. The used management strategies influence greatly the hybrid energy storage source performances. For this reason, a new online strategy is developed to improve the fuel consumption and the hybrid source lifetime. The performances (hydrogen consumption and applied stress on each source) of this new strategy are compared with those obtained with literature strategies for 700 km of range. Furthermore, an experimental validation of two online energy management strategies is carried out to validate the simulation results using 1-kW test bench. The experimental results prove that the developed strategy improves hydrogen consu...
ABSTRACT This paper introduces the concept of structural battery composite materials and their po... more ABSTRACT This paper introduces the concept of structural battery composite materials and their possible devices and the rationale for developing them. The paper presents an overview of the research performed in Sweden on a novel structural battery composite material. The research areas addressed include: carbon fibre electrodes, structural separators, multifunctional matrix materials, device architectures and material functionalization. Material characterization, fabrication and validation are also discussed. The paper focuses on a patented battery composite material technology. Here, carbon fibres are employed as combined negative battery electrodes and reinforcement, coated with a solid polymer electrolyte working simultaneously as electrolyte and separator with ability to transfer mechanical loads. The coated fibres are distributed in a conductive positive cathode material on an aluminium electron collector film. Efficient Li-ion transport between the electrodes is achieved by the solid polymer electrolyte coating being only a few hundred nanometres thick. Finally some outstanding scientific and engineering challenges are discussed. Such challenges, calling for further research are related to manufacture, development of new solid polymer electrolytes for improved multifunctionality and the lack of material models.
Abstract Gas evolution in lithium ion batteries (LIB) caused by degradation of the battery cell c... more Abstract Gas evolution in lithium ion batteries (LIB) caused by degradation of the battery cell components, is not only detrimental to cell performance, it is also a major safety risk. Understanding the connection between cell usage and gas evolution at different states of health of the battery is of utmost importance for the improvement of cell components as well as user protocols for LIBs. In this work, an electrochemical mass spectrometric in-operando cell house, capable of hosting a cylindrical 18650 cell, was developed and used to study the gas evolution at increasing cycle C-rates (from C/20 to 4C) between 2.6 V and 4.2 V and during stepwise increased/decreased cell voltages ranging from 2.2 V to 4.4 V. The cell under study was a commercial 1.5 Ah NMC-LMO/Graphite cell, pierced inside an Ar-filled glove box and mounted to the gas-tight cell house before being connected to the On-Line Electrochemical Mass Spectrometer (OEMS). The results show that the large capacity fade observed at high C-rate is associated to major evolution of ethylene gas. The voltage step experiments revealed that CO2 is the main gas evolving at high voltages (>4.15 V) and H2 at low (
International Journal of Greenhouse Gas Control, 2015
ABSTRACT Molten carbonate fuel cells (MCFC) used as active carbon dioxide concentrator units are ... more ABSTRACT Molten carbonate fuel cells (MCFC) used as active carbon dioxide concentrator units are a promising solution to reduce greenhouse gas (GHG) emissions from traditional combustion plants. The cell reaction transfers carbonate ions from the cathode to the anode and allows the fuel cell to simultaneously produce power and separate CO2 from a stream of flue gas. Carbon dioxide separation is of high interest for use in natural gas combined cycles and coal gas combustion plants, as a large part of anthropogenic CO2 worldwide originates from such installations. The flue gas from these types of combustion technologies typically contains 3–15% CO2, which is in the lower operational range of the MCFC. The aim of this work was to investigate the possibility to retrofit existing power plants with MCFC to reduce the total release of CO2 without necessarily reducing the power output, and to understand which kind of power plant could have the major benefits with an MCFC retrofitting. The performance of lab scale MCFC fed with simulated flue gas was evaluated, and a number of operational parameters, such as utilization factor and cathode humidification were varied to study the effect on fuel cell performance. The results show that it is feasible to operate the MCFC as a CO2 separator for simulated gas turbine flue gas; however, the voltage drop due to low CO2 concentration may restrict the operating window depending on various operating conditions.
To promote the development of anion exchange membrane fuel cells (AEMFC), an understanding of the... more To promote the development of anion exchange membrane fuel cells (AEMFC), an understanding of the oxygen reduction reaction (ORR) kinetics in porous gas diffusion electrodes is essential. In this work, experimental polarisation curves for electrodes with different platinum catalyst loadings and oxygen partial pressures at the cathode are fitted to a physics-based porous electrode model in the voltage range from open circuit voltage (OCV) to 0.7 V. The model is verified against polarisation curves with different anode platinum catalyst loading, and hydrogen partial pressures. The reactions are described using a two-step Tafel-Volmer pathway at the anode and concentration-dependent Butler-Volmer kinetics at the cathode. The model shows a good fit to the kinetic region with an exchange current density of 1.0e-8 A/cm2, for oxygen humidified to 95 % RH at 50 °C, a charge transfer coefficient of 0.8 and a first order dependence on oxygen partial pressure. For lower oxygen partial pressure...
ABSTRACT Mass transport in the electrolyte is one of the limiting processes when it comes to the ... more ABSTRACT Mass transport in the electrolyte is one of the limiting processes when it comes to the power density and energy efficiency of lithium-ion batteries. Electrolyte characterizations are therefore of utmost importance. This study reports the ionic conductivity, diffusion coefficient, lithium-ion transport number, and thermodynamic enhancement factor, as well as density and viscosity, for the electrolyte LiPF6 in EC:DEC (1:1, by weight) at 10°C, 25°C, and 40°C and for concentrations between 0.5 M and 1.5 M. By combining mathematical modeling and three experiments: conductivity measurements, concentration cells, and galvanostatic polarizations, the mass transport phenomena were fully characterized. All parameters were found to vary strongly with both concentration and temperature proving that temperature dependent parameters are essential when studying thermal behavior of lithium-ion batteries. Moreover, conductivity increased with temperature and showed a local maximum at around 1 M within the concentration range at all temperatures. The other parameters either showed a continuous decrease (diffusion coefficient and lithium-ion transport number) or increase (thermodynamic enhancement factor) with concentration at all temperatures. Limited liquid range leading to solvent crystallization at 10°C leads to very poor performance, possibly due to the strong coordination between the lithium ion and the crystallizing species, EC. Overall, the studied electrolyte is found to perform poorly compared to previously studied systems.
Thermal effects are linked to all main barriers to the widespread commercialization of lithium-io... more Thermal effects are linked to all main barriers to the widespread commercialization of lithium-ion battery powered vehicles. This paper presents a coupled 2D electrochemical - 3D thermal model of a ...
1 General Introduction The paper addresses a method to realise lithiumion batteries by electrogra... more 1 General Introduction The paper addresses a method to realise lithiumion batteries by electrografting of a very thin solid polymer electrolyte (SPE) coating on to carbon fibres. Carbon fibres featuring very high reversible capacity [1] were prepared to be employed as the negative electrodes in a novel structural battery device. A lithium-ion conductive, electrically insulating, polymer electrolyte [2, 3] with an average thickness of 470 nm was deposited around individual carbon fibres by cathodic electrografting [4]. In the paper, an electrocoating procedure applied on carbon fibre yarns, generating dense pinholefree SPE coatings on individual carbon fibres, in presence of a lithium salt as supporting electrolyte is presented and verified by microscopy. The coated fibres were employed in a novel battery concept paving the route towards a fully structural battery composite material.
Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 2020
This article presents a comparative study between the performances of different energy management... more This article presents a comparative study between the performances of different energy management strategies for hybrid energy storage source supplying electric vehicle. In our case, the hybrid supply is composed of fuel cell as an energy source and lithium-ion batteries as a power buffer. The two storage systems are connected to the DC bus via DC/DC boost converters. The used management strategies influence greatly the hybrid energy storage source performances. For this reason, a new online strategy is developed to improve the fuel consumption and the hybrid source lifetime. The performances (hydrogen consumption and applied stress on each source) of this new strategy are compared with those obtained with literature strategies for 700 km of range. Furthermore, an experimental validation of two online energy management strategies is carried out to validate the simulation results using 1-kW test bench. The experimental results prove that the developed strategy improves hydrogen consu...
ABSTRACT This paper introduces the concept of structural battery composite materials and their po... more ABSTRACT This paper introduces the concept of structural battery composite materials and their possible devices and the rationale for developing them. The paper presents an overview of the research performed in Sweden on a novel structural battery composite material. The research areas addressed include: carbon fibre electrodes, structural separators, multifunctional matrix materials, device architectures and material functionalization. Material characterization, fabrication and validation are also discussed. The paper focuses on a patented battery composite material technology. Here, carbon fibres are employed as combined negative battery electrodes and reinforcement, coated with a solid polymer electrolyte working simultaneously as electrolyte and separator with ability to transfer mechanical loads. The coated fibres are distributed in a conductive positive cathode material on an aluminium electron collector film. Efficient Li-ion transport between the electrodes is achieved by the solid polymer electrolyte coating being only a few hundred nanometres thick. Finally some outstanding scientific and engineering challenges are discussed. Such challenges, calling for further research are related to manufacture, development of new solid polymer electrolytes for improved multifunctionality and the lack of material models.
Abstract Gas evolution in lithium ion batteries (LIB) caused by degradation of the battery cell c... more Abstract Gas evolution in lithium ion batteries (LIB) caused by degradation of the battery cell components, is not only detrimental to cell performance, it is also a major safety risk. Understanding the connection between cell usage and gas evolution at different states of health of the battery is of utmost importance for the improvement of cell components as well as user protocols for LIBs. In this work, an electrochemical mass spectrometric in-operando cell house, capable of hosting a cylindrical 18650 cell, was developed and used to study the gas evolution at increasing cycle C-rates (from C/20 to 4C) between 2.6 V and 4.2 V and during stepwise increased/decreased cell voltages ranging from 2.2 V to 4.4 V. The cell under study was a commercial 1.5 Ah NMC-LMO/Graphite cell, pierced inside an Ar-filled glove box and mounted to the gas-tight cell house before being connected to the On-Line Electrochemical Mass Spectrometer (OEMS). The results show that the large capacity fade observed at high C-rate is associated to major evolution of ethylene gas. The voltage step experiments revealed that CO2 is the main gas evolving at high voltages (>4.15 V) and H2 at low (
International Journal of Greenhouse Gas Control, 2015
ABSTRACT Molten carbonate fuel cells (MCFC) used as active carbon dioxide concentrator units are ... more ABSTRACT Molten carbonate fuel cells (MCFC) used as active carbon dioxide concentrator units are a promising solution to reduce greenhouse gas (GHG) emissions from traditional combustion plants. The cell reaction transfers carbonate ions from the cathode to the anode and allows the fuel cell to simultaneously produce power and separate CO2 from a stream of flue gas. Carbon dioxide separation is of high interest for use in natural gas combined cycles and coal gas combustion plants, as a large part of anthropogenic CO2 worldwide originates from such installations. The flue gas from these types of combustion technologies typically contains 3–15% CO2, which is in the lower operational range of the MCFC. The aim of this work was to investigate the possibility to retrofit existing power plants with MCFC to reduce the total release of CO2 without necessarily reducing the power output, and to understand which kind of power plant could have the major benefits with an MCFC retrofitting. The performance of lab scale MCFC fed with simulated flue gas was evaluated, and a number of operational parameters, such as utilization factor and cathode humidification were varied to study the effect on fuel cell performance. The results show that it is feasible to operate the MCFC as a CO2 separator for simulated gas turbine flue gas; however, the voltage drop due to low CO2 concentration may restrict the operating window depending on various operating conditions.
To promote the development of anion exchange membrane fuel cells (AEMFC), an understanding of the... more To promote the development of anion exchange membrane fuel cells (AEMFC), an understanding of the oxygen reduction reaction (ORR) kinetics in porous gas diffusion electrodes is essential. In this work, experimental polarisation curves for electrodes with different platinum catalyst loadings and oxygen partial pressures at the cathode are fitted to a physics-based porous electrode model in the voltage range from open circuit voltage (OCV) to 0.7 V. The model is verified against polarisation curves with different anode platinum catalyst loading, and hydrogen partial pressures. The reactions are described using a two-step Tafel-Volmer pathway at the anode and concentration-dependent Butler-Volmer kinetics at the cathode. The model shows a good fit to the kinetic region with an exchange current density of 1.0e-8 A/cm2, for oxygen humidified to 95 % RH at 50 °C, a charge transfer coefficient of 0.8 and a first order dependence on oxygen partial pressure. For lower oxygen partial pressure...
ABSTRACT Mass transport in the electrolyte is one of the limiting processes when it comes to the ... more ABSTRACT Mass transport in the electrolyte is one of the limiting processes when it comes to the power density and energy efficiency of lithium-ion batteries. Electrolyte characterizations are therefore of utmost importance. This study reports the ionic conductivity, diffusion coefficient, lithium-ion transport number, and thermodynamic enhancement factor, as well as density and viscosity, for the electrolyte LiPF6 in EC:DEC (1:1, by weight) at 10°C, 25°C, and 40°C and for concentrations between 0.5 M and 1.5 M. By combining mathematical modeling and three experiments: conductivity measurements, concentration cells, and galvanostatic polarizations, the mass transport phenomena were fully characterized. All parameters were found to vary strongly with both concentration and temperature proving that temperature dependent parameters are essential when studying thermal behavior of lithium-ion batteries. Moreover, conductivity increased with temperature and showed a local maximum at around 1 M within the concentration range at all temperatures. The other parameters either showed a continuous decrease (diffusion coefficient and lithium-ion transport number) or increase (thermodynamic enhancement factor) with concentration at all temperatures. Limited liquid range leading to solvent crystallization at 10°C leads to very poor performance, possibly due to the strong coordination between the lithium ion and the crystallizing species, EC. Overall, the studied electrolyte is found to perform poorly compared to previously studied systems.
Thermal effects are linked to all main barriers to the widespread commercialization of lithium-io... more Thermal effects are linked to all main barriers to the widespread commercialization of lithium-ion battery powered vehicles. This paper presents a coupled 2D electrochemical - 3D thermal model of a ...
1 General Introduction The paper addresses a method to realise lithiumion batteries by electrogra... more 1 General Introduction The paper addresses a method to realise lithiumion batteries by electrografting of a very thin solid polymer electrolyte (SPE) coating on to carbon fibres. Carbon fibres featuring very high reversible capacity [1] were prepared to be employed as the negative electrodes in a novel structural battery device. A lithium-ion conductive, electrically insulating, polymer electrolyte [2, 3] with an average thickness of 470 nm was deposited around individual carbon fibres by cathodic electrografting [4]. In the paper, an electrocoating procedure applied on carbon fibre yarns, generating dense pinholefree SPE coatings on individual carbon fibres, in presence of a lithium salt as supporting electrolyte is presented and verified by microscopy. The coated fibres were employed in a novel battery concept paving the route towards a fully structural battery composite material.
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Papers by Göran Lindbergh