Semi-public charging infrastructure proposal

Given the current and future needs of the implementation of a charging infrastructure for Electric Vehicles (EV). There is great potential for the installation of such infrastructures in the car parks and mall centers.

Within these semi-public car parks, several business models can be established:

1. First, a business model in which you must pay for the charge.
2. Secondly, a model for which it is not necessary to pay, and, therefore, the customer or user of the EV may charge it without the need to make any payment or identification. The user paid indirectly using the services where is installed the semi-public charging infrastructure (Mall center; shops, restaurants, theater, etc.).

Both possibilities would incorporate a pole, or a Wallbox (depending on the location of the charging point in the car park: indoor or outdoor) with two type 2 sockets (Mode 3 by IEC 61851). (Modo 3 – IEC 61851).

Depending on the decision of the infrastructure manager, the charging systems could include communications, wireless or by Ethernet, all by remote control, even the simple “status” of the post; SOC (State of Charge), operation, availability, or even the state of the electrical protection, or simply the billing by the person in charge of the outlets. At the same time, if the service is performed by any outsourcing, a back office, the communication protocol must be managed by OCPP protocol, for the interoperability with other service providers.  OCPP.

Following the main features of the charging infrastructure, in this case, an accreditation system should be incorporated by means of an RFID (Radio-Frequency Identification) or NFC mobile phone protocol (Near-Field Communication), in case you want to have restricted access for authorized personal (as long as the parking can be in places where the access can be shared; large superficies like shops, recreation and restaurant areas, etc.). The system could also incorporate Visa payment system either conventional or contactless.

The second proposal is for parking lots with restricted access. For example, in IKEA, where the only people who have access to the car park are the costumers of the store itself, access that is not shared with other stores.

In this case, it is very likely that no user accreditation is required, since, in most cases it will not be necessary to make any payment, therefore no communications are crucial. It is a connect and charge system, always decided by the infrastructure manager.
In both cases mentioned before, poles will be installed that can simultaneously charge both outlets, each of them with the same power, in principle 7,4 kW in single-phase, of course, the design of the charging infrastructure can be open to three-phase 22 kW system, considering models like Tesla, Renault ZOE and BMW i3 can be charged using the three-phase system.

In some cases, the manager of the charging infrastructure may be interested in the customer spending as much time as possible in the mall or store, thus, the maximum power of the outlets would not exceed 22 kW, in order to slow down the charging process.

In terms of technical characteristic to be provided in the chargers, electrical protections for overcurrent and leakage must be installed. Those must be Surge Protection, Circuit Breakers, in that case, Mini Circuit Breakers (MCB) and protections for Residual Current, in that case Residual Current Device (RDC), if it is possible, type B, by the direct current component from the battery, also protections in the maneuvering of the pole are necessary. Overvoltage protections could be installed, but optionally, although they are recommended.

As a particular case, in case that the charging infrastructure has communications, protection systems can be installed with remote activation, or alternatively have auto-reclosing protections.

Depending on the requirements, it is possible to have a detection system in case of the core of the contactor cannot stuck up (from the socket), requirements that some brands such as Renault or Nissan demand although the international standard (IEC 61851) does not currently require it.

Notice: in this case, neither remotely resettable or self-resettable protection could be used (at least by the indications given by Nissan and Renault). 

The access to the outlets could be minimally protected, of course it is not an obligation, as it is a requirement in the French Market where it is necessary that the outlet is covered and it can only be opened when charging time, after the user authorization is obtained from the charger.

Aesthetically and visually, there will be a LED bar to indicate the status of each plug, if possible that it turns the entire pole so that the status (busy, available, etc.) can be seen from various points. From my point of view, display would not be included, because it is possible to use a mobile application wireless or by Bluetooth to be able to access the post data from any mobile device.

In case of having a pole with communications, a parking place detection system could be integrated. In some cases, the parking place is occupied but the car itself is not charging. Hence, it is recommendable to know if the car occupying the place, is charging, if not, the pole can send a message and the car will be towed.

Of course, the number of poles to install would be a decision of the infrastructure manager. Although, it is advisable to leave part of the electric and communication installed, despite not being used. If in the future, it is necessary to expand the installation, this fact will decrease the investment in case of increasing the number of poles (increase the charging infrastructure), in terms of electrical equipment, cables, power required in the installation, etc.

If in the future, the number of charging points is important in terms of electrical consumption, once the electrical installation has been dimensioned, the control of the charging system must be carried out, controlling the consumption with respect to where the installation that feeds the Cargo Infrastructure (load balancing systems to avoid trips due to overconsumption and therefore non-conformities in the service to the EV user)

JSR – Consulting conducts training for Technicians from the to Automotive and Transportation industry in general to work with High Voltage Systems in a safe manner.