Lluc Canals Casals

PHEV Battery Aging Study Using Voltage Recovery and Internal Resistance From Onboard Data

It is well known that batteries do not perform equally throughout their lifetimes. Their properties are in constant degradation, their capacity fades, and the maximum power reduces. Battery aging has been widely studied under laboratory-controlled conditions for different types of cells. In real life, however, every person has their own driving profile, which is almost unique and unpredictable, making the state of health (SOH) during real-life cycles highly difficult to estimate accurately. This paper presents a methodology for aging estimation based on data extracted from onboard data loggers installed in an electric vehicle (EV). When a driver turns off the vehicle, the battery voltage slowly increases until it finally reaches the open circuit voltage (OCV). It has been observed that the recovery voltage transition depends on the temperature and aging, providing new elements to verify the battery SOH.

Communications concerns for reused electric vehicle batteries in smart grids

Electric vehicles use 10 to 25 kWh batteries. After their use in cars, these batteries are still in good condition to be used for energy storage in stationary applications and smart grid systems at all stages: generation, transmission, and distribution. However, before their reuse, there are some changes to be made on these batteries, such as those concerning communications. Electric vehicle batteries use a battery management system that controls functionality and safety, transmitting their condition and status, but also containing confidential information. This article studies two strategies to deal with communications difficulties in their second life as storage energy devices.

EL ENVEJECIMIENTO DE LAS BATERÍAS DE UN VEHÍCULO ELÉCTRICO Y CÓMO LO PERCIBE EL CONDUCTOR

El vehiculo electrico esta entrando en el mercado de la automocion de manera suave pero continuada. Los vehiculos electricos que mayormente estan ocupando este nicho de mercado utilizan baterias de Litio-ion para almacenar la energia electrica. A parte de la velocidad de carga y de la autonomia de este tipo de vehiculos, una de las mayores preocupaciones que tienen, tanto los fabricantes de vehiculos como los posibles compradores, hace referencia al envejecimiento de las baterias. De un modo similar a lo que ocurre con las baterias de telefonos moviles y ordenadores portatiles, las baterias de vehiculos electricos van perdiendo prestaciones a lo largo de la vida del vehiculo. Es por este motivo que los fabricantes de automoviles han definido que una bateria ya no es apta para el sector de la automocion cuando esta ha perdido un 20% de su capacidad de almacenar energia. En este estudio se analiza el envejecimiento de una bateria de un vehiculo hibrido enchufable a lo largo de su vida util. Se muestran los factores que afectan a la perdida de capacidad de la bateria, con que proporcion lo hacen y con que medios se estudian, controlan y analizan. Asimismo, se valora que es capaz de percibir el conductor y como la bateria transmite su envejecimiento al resto de componentes del vehiculo.

A Cost Analysis of Electric Vehicle Batteries Second Life Businesses

In the following years thousands of electric cars are expected to be sold. Knowing that their batteries cannot be used for traction services after they have lost a 20 % of its capacity, there will be thousands of batteries available for re-use. The re-use represents a considerable environmental improvement compared to the immediate recycling. According to battery recycling enterprises, not even half of them are collected back after being used and car manufacturers should ensure that their electric vehicle batteries will be correctly processed. A second life added value might help for a better deposition and management control. Although interesting, the second life re-use is not simple. Vehicles should first arrive to the dispersed authorized processing centers in the country. Once there, batteries should be extracted, packed according to legal regulations and transported to the restoration plant, where they will be tested, their components revised and they will be prepared for the second life application. All this implies personnel, transport, installation amortization and spare part costs. This work will present how appropriate the idea of the battery recovery for second life applications is.

Aging model for re-used electric vehicle batteries in second life stationary applications

Energy generation and distribution around the globe expect that micro-grids, renewable and distributed energy services will be key elements in future grid infrastructures. That is why batteries, as storage energy systems, are in the scope of many studies. To counteract the high costs of Li-ion batteries appears the idea of electric vehicle battery reuse or second life for stationary applications. In fact, batteries from electric vehicles are not useful for transportation purposes after they have lost a 20% of its capacity. This study uses an electric equivalent circuit to model battery behavior and aging under five different second life applications: Fast charge of electric vehicles; isolated applications; uninterruptible power systems and Self consumption with and without participation on grid frequency regulation. The battery model takes into account temperature, C-rate, depth of discharge and voltage of the battery to evaluate and calculate battery aging along time and use. This model runs on Matlab and Simulink to determine the battery state of health evolution and, therefore, the rest of useful life, which can be used for future economic analysis and maintenance management.

Critical evaluation of European Union legislation on the second use of degraded traction batteries

Electric vehicles are one promising alternative towards a low carbon electric mobility future with less dependency on fossil fuels. The European Union automotive industry is a global leader but there currently exists no single EV targeted legislation that encourages the uptake of these sustainable technologies. In particular, the second use of degraded electric vehicle batteries in energy storage systems represents emerging economic and environmental opportunities as well as legal concerns that need to be addressed and managed in a timely manner. Hence, a more efficient regulatory framework in place will further increase the integration of renewable energy sources into the power system while at the same time creating a level playing field for an electric mobility transition in the European Union.

SEGUNDAS VIDAS PARA BATERÍAS DE COCHES ELÉCTRICOS: BUENAS IDEAS - MALOS NEGOCIOS

The industrial car manufacturers see in the high battery price an important obstacle for an electric vehicle mass selling, thus mass production. Therefore, in order to find some cost relieves and better selling opportunities, they look and push forward to find profitable second battery uses. This study presents, by showing different results and applications, the main goal as unachievable and indicates that most of the possibilities analyzed have such a low, if not negative, revenue for being considered a profitable business. Even in a supposed case of a suitable second use business, the buying price of old electric vehicles batteries would have decreased by a 90%, so there would not be a substantial price reduction applicable to new batteries. Therefore, no mass selling will occur and the “glorious” cycle will be broken.

An electric taxi fleet charged by second use batteries: not just economic profit

Purpose – The road transport sector is the second biggest CO2 emissions contributor after energy generation. In urban environments, its impact is increased due to the worse combustion engine driving efficiency. It is thought that electric mobility might bring some relief to big cities’ polluted air. At the same time, car manufacturers are searching for second battery applications in order to reduce its manufacture cost and make electric cars achievable for most people. This paper seeks to address these issues.Design/methodology/approach – This study presents an economic and environmental approach of an electric taxi fleet charged with second use electric car batteries. The environment impact comes from the possible CO2 emissions reduction due to the use of electricity instead of fuel and from reusing the old electric car batteries instead of brand new ones. On the economic side, apart from the financial and consumption costs and profits, the Kyoto protocol trades permit an economic evaluation of the benef...

A Critical Evaluation of Cathode Materials for Lithium-Ion Electric Vehicle Batteries

There has been an intensive research and development focus on lithium-ion batteries, which have revolutionized the electric vehicle market due to the batteries’ high energy and power density, longer lifespan, and increased safety than comparable rechargeable battery technologies. The performance of lithium-ion batteries is achieved by packaging design, electrolyte, and electrodes material’s selection. This study focuses on cathode materials as they currently need to overcome critical challenges. In fact, cathode materials affect energy density, rate capability and working voltage that led to the cathode currently costing twice as much as the anode. For this reason, this study reviews cathode materials for electric vehicle lithium-ion batteries under economic and environmental perspectives to optimize the batteries’ structures and properties. Findings reveal that presently there is no commercially installed battery that can satisfy both, economic and environmental concerns while offering an overall excellent performance.