Julia Drillkens

A review of current automotive battery technology and future prospects

In this article, today’s battery technologies and future options are discussed. Batteries have been one of the main focuses of automotive development in the last years. Technologies that have been in use for a very long time, such as the lead–acid battery, are indispensable but need improvement. New technologies such as the lithium-ion battery are entering the market. Supercapacitors (also known as electrochemical double-layer capacitors) can be used for high-power requirements such as regenerative braking. The variety of vehicles has increased with the introduction of hybrid vehicles, plug-in hybrid vehicles and electric vehicles and, for each type, suitable battery types are being used or under development. Appropriate battery system designs and charging strategies are needed. Battery technologies can be classified according to their energy density, their charge and discharge characteristics, system integration and the costs. Further relevant performance parameters are the calendar lifetime, the cycle lifetime, the low- and high-temperature performances and the safety.

Nafion Hybrid Membranes for Use in Redox Flow Batteries

The membrane is the key component of a redox flow system, as it has to avoid cross-contamination of the ions of the active material as well as to permit high proton conductivity. A membrane with drastically reduced cross-contamination ability would overcome the main problem of several redox couples and, in consequence, a wider variety of redox couples would potentially allow redox flow systems with higher energy densities or lower material costs. This work deals with modifications of Nafion membranes to decrease the cross-contamination ability without affecting the proton conductivity. Several in situ gel reactions were used for modification of the membranes. Cross-contamination has been reduced in this work by a factor of 2 compared to previous works by Xi et al. [J. Power Sources, 166, 531 (2007)] and Teng et al. [J. Power Sources, 189, 1240 (2009)].

Speicherung der elektrischen Energie

Die Speicherung der elektrischen Energie im Fahrzeug und ihre bedarfsabhangige Abgabe gehoren neben den elektrischen Maschinen (siehe auch Kapitel 2.2 und 2.3) und der Leistungselektronik (siehe Kapitel 4.1) zu den Schlusseltechnologien fur die Elektrifizierung des Antriebsstrangs. Die Batterie (genau gesprochen der Akkumulator wegen der Wiederaufladbarkeit) ist der heute ublicherweise eingesetzte Energiespeicher. Schon vor etwa 100 Jahren sind die damals dominierenden Elektrofahrzeuge an der Batterietechnik gescheitert. Die Batterien waren zu schwer, zu gros und hatten eine zu geringe Speicherkapazitat. Die jahrzehntelange Entwicklung fuhrte inzwischen zu Alternativen zur konventionellen Bleibatterie, wie der Nickel-Cadmium-, der Nickel-Metall- Hydrid- oder der Lithium-Ionen- Batterie. Nachfolgend werden die Grundlagen der Batterietechnik beschrieben. Die Lithium-Ionen-Batterie als besonders erfolgversprechende Entwicklung fur den Fahrzeugeinsatz wird in Kapitel 3.2 vorgestellt.