Electromobility is a central research area of the FFE and is part of numerous research projects. In the following series of articles, different topics are presented. One focus is on scenarios for electric vehicles and charging stations in Germany. Furthermore, the different charging plugs are explained and different possibilities of grid integration by controlled and bidirectional charging are described. Finally, the climate footprint of electric vehicles is discussed.
This article is the third of a series of 7 articles which will now be published successively on our website.
|Overview of the topics of the article series on electromobility|
|1.||Development of electromobility
|4.||Private and public charging|
|6.||Use Cases for bidirectional charging|
|7.||Climate assessment of electric vehicles|
Nowadays, cable-bound charging is by far the most important charging technology in terms of the spread of charging infrastructure and its use. The electricity provided at the charging point can be either direct (DC) or alternating current (AC) and depending on the geographical location, the charging connection will differ.
While the DC charging points are recognized as fast due to their high powers, AC charging points do not need expensive rectifiers. In Germany, the Federal Network Agency has designated powers below 22kW as normal charging and above as fast charging. So, of the 13,000 publicly accessible charging stations available in Germany, 3,050 (12%) have at least one fast charging point (as of March 2020, Bundesnetzagentur). 
Two main organizations define plug types and power levels: the International Electrochemical Commission (IEC) and the Society of Automotive Engineers (SAE). In addition to alternating and direct current charging, three charging levels (IEC) and four different charging modes (SAE) can be distinguished. These categories are characterized in the following table. 
Table 1. Characteristics of charging levels as defined by the SAE and charging modes as defined by the IEC 
The charging of an electric vehicle (EV) can be done with different types of plugs depending on the charging level. For AC charging, IEC-62196-2 specifies two connector types widely used, type 1 and type 2. The type 1 connector was developed in Japan and is firmly anchored in North America and Japan (SAE J1772/2009). The type 2 connector developed in Germany (also known as "Mennekes") is the European standard today and is described in IEC 62196-2.
In contrast to the AC trajectory, for which standardization was sought on a continental scale, the DC trajectory is characterized by a struggle for global standardization. The development of DC charging systems was initiated by the Japanese power company TEPCO (2007). Fast charge coupler (JEVS G105-1993), CHAdeMO was proposed in 2010 as a global standard and included in the IEC 61851-23, -24 (charging system and communication) and the IEC 62196 standard as configuration AA. However, this standard definition was later challenged by a large consortium of firms with their own standard. Nowadays, a strong increase in the use of the Combined Charging System (CCS) in North America and Europe, compared to the CHAdeMO system can be expected. Meanwhile, China, which has the world’s largest electric vehicle market, also does not use the CHAdeMo standard, but its own GB/T.
Table 2. Characteristics plug types