Benedikt Lunz

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.

Optimizing vehicle-to-grid charging strategies using genetic algorithms under the consideration of battery aging

Lithium-ion battery aging tests show that battery lifetime can be strongly influenced by the operating conditions, particularly by the state of charge and the cycle depth. Therefore a genetic optimization algorithm is applied to optimize the charging behavior of a plug-in hybrid electric vehicle (PHEV) connected to the grid with respect to maximizing energy trading profits in a vehicle-to-grid (V2G) context and minimizing battery aging costs at the same time. The simulation shows that the algorithm is able to increase the battery lifetime drastically and therefore reduces the mobility costs for the vehicle owner.

Battery Sizing for Serial Plug-in Hybrid Vehicles: A Model-Based Economic Analysis for Germany

The battery size of a Plug-in Hybrid Electric Vehicle (PHEV) is decisive for the pure electrical range of the vehicle and crucial for the cost-effectiveness of this particular vehicle concept. Based on the energy consumption of a conventional reference car and a PHEV, we introduce a comprehensive total cost of ownership model for the average car user in Germany for both vehicle types. The model takes into account the purchase price, fixed annual costs and variable operating costs. The amortization time of a PHEV also depends on the recharging strategy (once a day, once a night, after each trip), the battery size as well as the battery costs. We find that PHEVs with a 4 kWh battery and at current lithium-ion battery prices reach the break-even point after about six years (five years when using the lower night-time electricity tariffs). With higher battery capacities the amortization time becomes significantly longer. Even with the small battery size and assuming the EU-15 electricity mix, a PHEV is found to emit only around 60% of the CO2 emissions of a comparable conventional car. Thus, with the PHEV concept a cost-effective introduction of electric mobility and reduction of greenhouse gas emissions per vehicle can be reached.

Life Cycle Cost Calculation and Comparison for Different Reference Cases and Market Segments

This chapter describes how life cycle cost (LCC) calculation can be used for energy storage schemes to determine the most cost-efficient technology for a given application with regard to certain side conditions. Parameters which describe the storage technology and application are introduced in order to describe the method for LCC calculation. Examples of LCC calculations are shown for different reference cases. The chapter closes with a sensitivity analysis of the most important parameters.

Overview of Nonelectrochemical Storage Technologies

In addition to electrochemical storage systems there are alternative technologies to store electric energy, which are based upon different physical principles. It is not sufficient to evaluate these storage technologies with respect to their technical parameters alone. In fact, an analysis of strengths, weaknesses, opportunities, and threats gives a good basis for the evaluation of a technology and its deployment potential. This chapter contains descriptions and evaluations of technically and operationally proven storage systems such as mechanical, electrical, and thermoelectric storage. Technologies that are still in the concept phase, are also briefly discussed.

Evaluating the value of concentrated solar power in electricity systems with fluctuating energy sources

The paper presents a method for evaluating the value of CSP in electricity systems in comparison to other technologies. The low parametrization effort of the presented model allows for conducting studies for different electricity systems and scenarios within a manageable time frame. CSP systems in possible German electricity systems in the year 2050 can be used at its best, when the share of fluctuating renewables (FRES) is low. Under these conditions CSP is a cost-effective solution to meet CO2-reduction goals of 90 % in comparison to 1990. With FRES shares above 70 % the utilization of CSP systems would be too low to be competitive.

‘Double Use’ of Storage Systems

Abstract Many batteries technologies provide more performance, especially regarding cycle life, than needed in their applications. As batteries also unfortunately age without being cycled at all (‘calendar lifetime’) it is worthwhile to apply the batteries to one or more other markets at the same time. This can increase the utilization of storage systems and, at the same time, decrease operational costs. In this chapter the primary use cases of uninterruptible power supplies (22.2), electric vehicle batteries (22.3), and photovoltaic home storage systems (22.4) are described in detail and potential scenarios for double use in the different applications are discussed. Another way of improving the economics of batteries systems is to transfer batteries systems to a ‘second life’ application. Opportunities and threats are discussed in Section 22.5 .