Communication protocols

There are differences in communication methods of the various charging protocols. Protocols rely on different physical connections and there is little scope to make these approaches compatible (IEA, 2018a). Basic charging requirements for nearly all chargers are described in the IEC 61851-1 standard (IEC, 2017). Level 1, level 2 and Tesla AC connectors have no direct communication in their cables and require off-board controls for authentication, payment and smart charging, such as via an app (ElaadNL, 2017). Level 3 AC chargers have basic signalling that only regulate the charging speed, thus requiring external controls for communication as well. In the case of DC fast chargers, CCS connectors are coupled with power line communication (PLC) protocols, while CHAdeMO, Tesla and GB/T use controller area network (CAN) communication (IEA, 2018a). The recent ISO/IEC 15118 protocol provides more functionality to enable vehicle-to-grid (V2G) communication and was added to the CCS protocol in 2018, whereas for AC charging the car manufacturer has to implement this from the vehicle perspective (CharIN, 2018c) (see Chapter 5, Implications of electric mobility for power systems). The option for V2G communication has been part of the CHAdeMO protocol for several years (CHAdeMO, 2019).

The use of the CAN communication, which mandates a minimum for peripheral communication (e.g. authentication, verification and payment) in DC charging, places less emphasis on the vehicle and more emphasis on the charger, which is effectively the master for any additional (and more complex) communication (for example those that govern smart charging practices and require communication with the power supplier). This has the implicit consequence of giving greater relevance to the role of the charging point operator (as opposed to the vehicle) and it appears consistent with the prominent role of TEPCO (a major utility in Japan and a supporter of the EV30@30 Campaign) in the development of the standard (Anegawa, 2010). Similarly, the use of the more complex PLC protocol in the CCS standard places more emphasis on the role of the vehicle (which is the master for more complex communications), but the latest version of the standard also provides that the master role can go to the charging point operator. This is consistent with the strong engagement of the car industry in the CharIN consortium (CharIn, 2019c), the main proponent of the CCS specifications.

The recent developments of different adapters (conversion device between standards) between charging standards (and therefore also the capacity for EVs to handle the related communication protocols) show that the issue of the double standardisation currently in place and the related differences on communication protocols (CAN versus PLC) can be overcome. Even if this does come at a net cost (which could be avoided if multiple standards converge into one standard), recent developments, (e.g. Tesla case), indicate that costs for facilitating the increase in flexibility to use multiple chargers are manageable.

Supporting policies

Many policy developments in 2018 and 2019 support the uptake of EVs and the roll-out of charging infrastructure. They will have varying levels of impact on the EV market. Some key regions cover all policy types for EV uptake and electric vehicle supply equipment (EVSE), whereas others focus on specific measures (Table 1). This section also provides updates detailed by country.