Advances in Battery Technologies for Electric Vehicles

Bruno Scrosati, Jürgen Garche, Werner Tillmetz, Jurgen Garche

• Publisher: Woodhead Publishing
• Year: 2015
• Print ISBN: 9781782423775
• eBook ISBN: 9781782423980
• Topic: Technology & Engineering
• Subtopic: Mechanical Engineering
• Index: Technology & Engineering

Advances in Battery Technologies for Electric Vehicles provides an in-depth look into the research being conducted on the development of more efficient batteries capable of long distance travel.The text contains an introductory section on the market for battery and hybrid electric vehicles, then thoroughly presents the latest on lithium-ion battery technology.Readers will find sections on battery pack design and management, a discussion of the infrastructure required for the creation of a battery powered transport network, and coverage of the issues involved with end-of-life management for these types of batteries.- Provides an in-depth look into new research on the development of more efficient, long distance travel batteries- Contains an introductory section on the market for battery and hybrid electric vehicles- Discusses battery pack design and management and the issues involved with end-of-life management for these types of batteries

Part One

Introduction

1

Introduction to hybrid electric vehicles, battery electric vehicles, and off-road electric vehicles

F. Herrmann; F. Rothfuss Fraunhofer Institute for Industrial Engineering IAO, Stuttgart, Germany

Abstract

The finite nature of the fossil fuel supply, strong regulations such as the CO₂ limits and the wish for pollution-free mobility has led to a great variety of electric drives for road and off-road vehicles. Beside various hybrid propulsion technologies, there exist battery electric and even fuel cell electric concepts. Each system configuration has unique advantages and disadvantages and is suitable for different applications. Therefore the battery technologies play an important role in fulfilling the numerous requirements in shown vehicle concepts. This chapter as a general introduction gives an overview of the whole range of electric drives for different applications, guiding readers to the following chapters that focus on the advances in one of the key research fields “battery technologies for electric road and off-road vehicles”.

Keywords

Electric road vehicles

Off-road vehicles

Electric drive train concepts

Hybrid electric vehicles

Fuel cell electric vehicles

Electric vehicle applications

Battery technologies.

1.1 Electric mobility: mobility of the future

1.1.1 The importance of electric mobility to overcome future challenges

A current topic of discussion is how to overcome future challenges to society, including climate change and the finite nature of fossil fuels. One result will be the enactment of stricter regulatory requirements in upcoming years regarding the reduction of CO₂ emissions caused by conventional vehicles. For example, in the European Union (EU), cars are responsible for approximately 12% of total EU emissions of carbon dioxide (CO₂), “which can be seen as the main greenhouse gas” (European Commission, 2013). The CO₂ targets that the European Union legislated in 2009 and which were settled by the European Commission in July 2012 provide that the fleet average to be achieved by all new cars is 130 grams of CO₂ per kilometer (g/km) by 2015. The target to be achieved by 2021 was set to 95 grams of CO₂ per kilometer (g/km) (European Commission, 2014).¹

Other factors include strong urbanization and the general population’s increasing interest in environmental issues; these factors indicate the need for pollution-free alternatives to the existing conventional vehicles that are driven by internal combustion engines (United Nations, 2012; Foth and Hellwig, 2011). Additionally, a change is evident in people’s behavior concerning vehicle ownership and the acceptance of new forms of mobility, such as car sharing, which also enables the potential for electric vehicles in current society (Bratzel and Lehmann, 2010).

There is a need for change not only in tomorrow’s passenger cars but also in buses and off-road vehicles. All of these can benefit from recent developments in electric propulsion systems. In addition to the issue of rising fuel prices, the working costs of these vehicles over their life cycles are enormous, and these issues can be regarded as a good point of action for solutions based on electric mobility.

1.1.2 Existing technological fundamentals and potential development paths

Every electric propulsion system is based on key components that make the concept work. The most important components are the energy storage device (battery system),² the electric machine, the power electronics, and a suitable charging device.

The energy storage device in general plays a significant role in determining technical attributes such as performance and range. Energy storage devices can be differentiated by type of rechargeable battery (e.g., lead-acid, nickel-metal hydride, or lithium-ion [Li-ion] battery), capacitors, or use of hydrogen as an energy source together with the fuel cell working as an energy converter. The different battery alternatives vary in their gravimetric energy density (Wh/kg) and their power density (W/kg).³ Compared to other types of energy sources (e.g., hydrogen or gasoline), the secondary batteries have a significant lower energy density. However, this disadvantage is compensated to a certain degree by the higher efficiency of the electric drivetrain as compared to conventional combustion engines.

The user must install several battery packs in the vehicle to ensure a certain level of range, although this leads to a higher overall vehicle weight under today’s state of technology (Spath et al., 2011; Eckstein et al., 2010). In addition to energy density, other aspects that must be considered when selecting the appropriate storage system include power density, lifetime and safety aspects, usable capacity (depth-of-discharge), and storage system costs (Oertel, 2008; Spath et al., 2011). To guarantee performance, many different subsystems are developed within the battery system (e.g., a battery management system or a suitable thermal management system).

Under current development conditions, there is not just one suitable energy storage device. The different types available have unique advantages and disadvantages, each of which must be considered together with the whole drivetrain architecture, and always along with the requirements of the application chosen.

Within an electric propulsion system the core component of the electric machine⁴ can improve, extend, or even replace the combustion engine as a propulsion source. For example, in the concepts of the range-extender vehicle, the battery electric vehicle (BEV), or the fuel cell vehicle, the electric motor is defined as the single propulsion source.

Unlike the combustion engine the electric machine has an outstanding torque characteristic (maximum torque is available from 0 revs per minute [rpm]), which makes the electric machine a great choice for the propulsion motor in vehicles. Furthermore, electric machines are characterized by high efficiency (90% or more), robustness and long service life, low maintenance costs, and a relatively low noise level (Spath et al...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Woodhead Publishing Series in Energy
• Part One: Introduction
• Part Two: Types of battery for electric vehicles
• Part Three: Battery design and performance
• Part Four: Infrastructure and standards
• Index