EPE Association: EPE 2017 - DS3o: Battery related issues

EPE 2017 - DS3o: Battery related issues
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 08: e-Mobility > EPE 2017 - DS3o: Battery related issues

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   Aging Analysis of a NMC/LTO cell by Impedance Model Parametrization
By Neeta KHARE [View]
[Download]

Abstract: The paper describes the aging behavior of the NMC/LTO li-ion cell using impedance model of the cell when cycled at different operating conditions. Paper depicts change in impedance with state of charge and cycle life. Both, solution and charge transfer, resistances increase at different stages of battery life. Change is Solution resistance (R1) is impacted by electrolyte decompositions as it changes significantly when discharge from 50 to 0\%. However, it changes very little when discharge from 100 to 50\% SOC. With model parameters variations, it seems C-rate has bigger impact on diffusion rather than on cell resistances and capacitances.

   Design Metrics of Compensation Methods for Contactless Charging of Electric Vehicles
By Hedieh MOVAGHARNEJAD [View]
[Download]

Abstract: Contactless power transfer (CPT) is an emerging topic which relies in high frequency resonant inverters to transfer power from a transmitter to a physically separated receiver inductively. Capacitive compensations on both the primary and secondary sides of a loosely coupled transformer are usually employed in recent researches in order to enhance the power transfer capability and the system efficiency. Achieving high efficiency, high power transfer and control capability of the output voltage and current of a compensated CPT circuit are conflicting criteria under variable loads and coupling coefficients. This paper studies the most important design metrics to choose the appropriate compensation method for high power applications. Series- series (SS) and series- parallel (SP) topologies as the two most economical configurations are focused in this paper and their main characteristics are extracted. It is investigated how to select the source frequency and compensation capacitors appropriately to achieve the best ideal functionality of the CPT system independent of output load and coupling coefficient variations, while providing the maximum efficiency. The design procedures are proposed and experimentally verified by a 3 kW prototype. Based on the results, SS configuration demonstrates as the best suited topology for charging the battery of electric vehicles (EVs).

   Design of a transformer for high power density charger - electric vehicles application
By Eléonore TAUROU [View]
[Download]

Abstract: This paper discusses the design of a high power density transformer for a high-frequency DC-DC charger for electric vehicles (EV). Because transformer is an important part of bulky components in charger, efforts are concentrated on it. In classical transformer design, core shape and windings are determined by the charger specifications. The best design is chosen according to core and copper losses. With the use of new GaN transistors, some charger specifications can be widely improved such as switching frequency and power level. A simulation model is built to optimize transformer in different operating points in order to find the most compact transformer. The model is verified by measurements on a transformer prototype. Finally, a 7.3kW transformer with a volume of 27cm3 is chosen. At this power level, transformer losses are around 20W at 500 kHz achieving around 99.7\% efficiency. Resulting transformer power density is 270kW/m3.

   Lithium-ion Batteries: Comprehensive Technical Analysis of Second-Life Batteries for Smart Grid Applications
By Mohamed ABDEL-MONEM [View]
[Download]

Abstract: In the upcoming years, thousands of battery storage systems will be decommissioned from electric vehicles. Instead of recycling or sending them immediately to landfills, these battery systems could be reused in other applications, such as grid or end-user applications. Second-life batteries are still expected to be capable of storing and delivering substantial energy. It is possible that they could satisfy the requirements of stationary applications. Indeed, the total lifetime value of the battery will increase when the remaining capacity of batteries can be invested to meet the requirements of other energystorage applications. Consequently, the price of battery systems will be decreased, which helps the widespread commercialization both of electric vehicles and grid storage systems. However, there is an increasing need to investigate the potential of using second-life batteries in stationary applications (i.e., electric supply, ancillary services, grid system, end user/utility customer, and renewable integration). While some used battery technologies are now ready for commercial demonstration, there is no clear market structure to demonstrate the benefits of the used batteries for grid applications. While the need and opportunities for second-life batteries are obviously a number of gaps and limitations currently constrain the adoption of using the second-life batteries for grid-scale applications. Therefore, in this article, a comprehensive technical analysis is provided by addressing all aspects of a battery's life cycle to investigate the feasibility of reusing the retired EV batteries in stationary applications. Thismanuscript provides the experimental verification of the proposed solutions in order to face the main technical challenges, such as: lack of standards and models, aggravation of the aging process, difficulty testing and sorting staggering number of batteries, and inefficient of circuits and operational scenarios. Furthermore, Battery model is designed and verified by using MATLAB/Simulink environment.

   Parameter estimation for equivalent electrical model of lithium-ion cell
By Grzegorz DZIECHCIARUK [View]
[Download]

Abstract: This paper presents an estimation procedure of equivalent electric circuit parameters of a lithium-ion cell using data from a pulse charge/discharge test. An extraction process of the model parameters is based on a transient voltage response of relaxation process following a current pulse. The entire procedure is straightforward and there is no restriction in a number of parallel RC-branches in the electrical model. Convergence problem of the parameter estimation process, existing in classic solutions, is solved by application of a particle swarm optimization method (PSO). The entire parameter identification procedure is performed in automated way in order to reduce time required to obtain a sufficient set of parameter values for different states of charge. The model is verified based on experimental data.

   Proposal of the Passive type Dynamic Wireless Power Transfer System for EVs
By TOMIO YASUDA [View]
[Download]

Abstract: In this paper, we clarify the problem of power supply characteristics when the secondary coil of the PS resonance type DWPT system , and have proposed a technology that enables high efficiency and stable power supply at the time of moving the secondary coil and revealed its effectiveness.

   Sensorless inductive power transfer system for electric vehicles: strategy and control for automatic dynamic operation
By Paul-Antoine GORI [View]
[Download]

Abstract: This article focuses on Inductive Power Transfer to implement dynamic charging for electric vehicles.The system proposed is composed of adjacent 50-cm-side square coils set on the road, with only the coilunder the vehicle activated for power transfer. It relies on a symmetrical circuit coupled to a symmetricalcontrol using ZPA regulation to operate frequency-varying inverters, using soft switching around90 kHz. This system is able to deal with large coupling factor variations (between 0.1 and 0.26, andeven more), which allows to use same-size coils on the ground and on the vehicle, to reduce stray fieldand improve safety. Moreover, the regulation works with no communication between the vehicle and theroad. The idea of short-circuiting a ground coil and its resonant capacitor has been used to determine theposition of the vehicle in order to switch from one activated inverter to the next for dynamic operation.Different scenarios were investigated and experimented regarding the different possible states of groundinductances: on, off or short-circuited with the capacitor. This study leaded to the choice of a scenarioimplemented on a 2.4-kW prototype involving a Renault Twizy as the vehicle carrying the secondaryinductance. The control method employed allows dynamic operation with no additional sensor, resultingin a very good time response of 4 ms, coherent with a motorway application.

   Study on a capacitive coupling wireless power transfer with electric vehicle's dielectric substrates for charging an electric vehicle
By Kang Hyun YI [View]
[Download]

Abstract: This paper studies a capacitive coupling wireless power transfer (CCWPT) for charging electric vehicles by using the dielectric substrate outside of a vehicle. The CCWPT can replace a conventional inductive coupling wireless power transfer because it has less electro-magnetic interference (EMI) and heat dissipation. However, since the CCWPT has limitation on transferring high power due to too small coupling capacitance, it is hard to transfer large power and high voltage is generated. In this paper, it considers the substrates outside of a vehicle to obtain the large coupling capacitance. Furthermore, a proposed CCWPT employs a new power conversion circuit to obtain high efficiency and large power transferring with the implemented coupling capacitance. The new CCWPT circuit uses glasses in a vehicle and LLC resonant operation with two transformers to reduce a switching loss of power conversion circuit. As results, the proposed capacitive power transfer can transfer large power and have good efficiency. Verification of operation and features of the proposed system shows with a 200W prototype.

EPE 2017 - DS3o: Battery related issues
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 08: e-Mobility > EPE 2017 - DS3o: Battery related issues
	[return to parent folder]

	Aging Analysis of a NMC/LTO cell by Impedance Model Parametrization By Neeta KHARE	[View] [Download]
Abstract: The paper describes the aging behavior of the NMC/LTO li-ion cell using impedance model of the cell when cycled at different operating conditions. Paper depicts change in impedance with state of charge and cycle life. Both, solution and charge transfer, resistances increase at different stages of battery life. Change is Solution resistance (R1) is impacted by electrolyte decompositions as it changes significantly when discharge from 50 to 0\%. However, it changes very little when discharge from 100 to 50\% SOC. With model parameters variations, it seems C-rate has bigger impact on diffusion rather than on cell resistances and capacitances.

	Design Metrics of Compensation Methods for Contactless Charging of Electric Vehicles By Hedieh MOVAGHARNEJAD	[View] [Download]
Abstract: Contactless power transfer (CPT) is an emerging topic which relies in high frequency resonant inverters to transfer power from a transmitter to a physically separated receiver inductively. Capacitive compensations on both the primary and secondary sides of a loosely coupled transformer are usually employed in recent researches in order to enhance the power transfer capability and the system efficiency. Achieving high efficiency, high power transfer and control capability of the output voltage and current of a compensated CPT circuit are conflicting criteria under variable loads and coupling coefficients. This paper studies the most important design metrics to choose the appropriate compensation method for high power applications. Series- series (SS) and series- parallel (SP) topologies as the two most economical configurations are focused in this paper and their main characteristics are extracted. It is investigated how to select the source frequency and compensation capacitors appropriately to achieve the best ideal functionality of the CPT system independent of output load and coupling coefficient variations, while providing the maximum efficiency. The design procedures are proposed and experimentally verified by a 3 kW prototype. Based on the results, SS configuration demonstrates as the best suited topology for charging the battery of electric vehicles (EVs).

	Design of a transformer for high power density charger - electric vehicles application By Eléonore TAUROU	[View] [Download]
Abstract: This paper discusses the design of a high power density transformer for a high-frequency DC-DC charger for electric vehicles (EV). Because transformer is an important part of bulky components in charger, efforts are concentrated on it. In classical transformer design, core shape and windings are determined by the charger specifications. The best design is chosen according to core and copper losses. With the use of new GaN transistors, some charger specifications can be widely improved such as switching frequency and power level. A simulation model is built to optimize transformer in different operating points in order to find the most compact transformer. The model is verified by measurements on a transformer prototype. Finally, a 7.3kW transformer with a volume of 27cm3 is chosen. At this power level, transformer losses are around 20W at 500 kHz achieving around 99.7\% efficiency. Resulting transformer power density is 270kW/m3.

	Lithium-ion Batteries: Comprehensive Technical Analysis of Second-Life Batteries for Smart Grid Applications By Mohamed ABDEL-MONEM	[View] [Download]
Abstract: In the upcoming years, thousands of battery storage systems will be decommissioned from electric vehicles. Instead of recycling or sending them immediately to landfills, these battery systems could be reused in other applications, such as grid or end-user applications. Second-life batteries are still expected to be capable of storing and delivering substantial energy. It is possible that they could satisfy the requirements of stationary applications. Indeed, the total lifetime value of the battery will increase when the remaining capacity of batteries can be invested to meet the requirements of other energystorage applications. Consequently, the price of battery systems will be decreased, which helps the widespread commercialization both of electric vehicles and grid storage systems. However, there is an increasing need to investigate the potential of using second-life batteries in stationary applications (i.e., electric supply, ancillary services, grid system, end user/utility customer, and renewable integration). While some used battery technologies are now ready for commercial demonstration, there is no clear market structure to demonstrate the benefits of the used batteries for grid applications. While the need and opportunities for second-life batteries are obviously a number of gaps and limitations currently constrain the adoption of using the second-life batteries for grid-scale applications. Therefore, in this article, a comprehensive technical analysis is provided by addressing all aspects of a battery's life cycle to investigate the feasibility of reusing the retired EV batteries in stationary applications. Thismanuscript provides the experimental verification of the proposed solutions in order to face the main technical challenges, such as: lack of standards and models, aggravation of the aging process, difficulty testing and sorting staggering number of batteries, and inefficient of circuits and operational scenarios. Furthermore, Battery model is designed and verified by using MATLAB/Simulink environment.

	Parameter estimation for equivalent electrical model of lithium-ion cell By Grzegorz DZIECHCIARUK	[View] [Download]
Abstract: This paper presents an estimation procedure of equivalent electric circuit parameters of a lithium-ion cell using data from a pulse charge/discharge test. An extraction process of the model parameters is based on a transient voltage response of relaxation process following a current pulse. The entire procedure is straightforward and there is no restriction in a number of parallel RC-branches in the electrical model. Convergence problem of the parameter estimation process, existing in classic solutions, is solved by application of a particle swarm optimization method (PSO). The entire parameter identification procedure is performed in automated way in order to reduce time required to obtain a sufficient set of parameter values for different states of charge. The model is verified based on experimental data.

	Proposal of the Passive type Dynamic Wireless Power Transfer System for EVs By TOMIO YASUDA	[View] [Download]
Abstract: In this paper, we clarify the problem of power supply characteristics when the secondary coil of the PS resonance type DWPT system , and have proposed a technology that enables high efficiency and stable power supply at the time of moving the secondary coil and revealed its effectiveness.

	Sensorless inductive power transfer system for electric vehicles: strategy and control for automatic dynamic operation By Paul-Antoine GORI	[View] [Download]
Abstract: This article focuses on Inductive Power Transfer to implement dynamic charging for electric vehicles.The system proposed is composed of adjacent 50-cm-side square coils set on the road, with only the coilunder the vehicle activated for power transfer. It relies on a symmetrical circuit coupled to a symmetricalcontrol using ZPA regulation to operate frequency-varying inverters, using soft switching around90 kHz. This system is able to deal with large coupling factor variations (between 0.1 and 0.26, andeven more), which allows to use same-size coils on the ground and on the vehicle, to reduce stray fieldand improve safety. Moreover, the regulation works with no communication between the vehicle and theroad. The idea of short-circuiting a ground coil and its resonant capacitor has been used to determine theposition of the vehicle in order to switch from one activated inverter to the next for dynamic operation.Different scenarios were investigated and experimented regarding the different possible states of groundinductances: on, off or short-circuited with the capacitor. This study leaded to the choice of a scenarioimplemented on a 2.4-kW prototype involving a Renault Twizy as the vehicle carrying the secondaryinductance. The control method employed allows dynamic operation with no additional sensor, resultingin a very good time response of 4 ms, coherent with a motorway application.

	Study on a capacitive coupling wireless power transfer with electric vehicle's dielectric substrates for charging an electric vehicle By Kang Hyun YI	[View] [Download]
Abstract: This paper studies a capacitive coupling wireless power transfer (CCWPT) for charging electric vehicles by using the dielectric substrate outside of a vehicle. The CCWPT can replace a conventional inductive coupling wireless power transfer because it has less electro-magnetic interference (EMI) and heat dissipation. However, since the CCWPT has limitation on transferring high power due to too small coupling capacitance, it is hard to transfer large power and high voltage is generated. In this paper, it considers the substrates outside of a vehicle to obtain the large coupling capacitance. Furthermore, a proposed CCWPT employs a new power conversion circuit to obtain high efficiency and large power transferring with the implemented coupling capacitance. The new CCWPT circuit uses glasses in a vehicle and LLC resonant operation with two transformers to reduce a switching loss of power conversion circuit. As results, the proposed capacitive power transfer can transfer large power and have good efficiency. Verification of operation and features of the proposed system shows with a 200W prototype.