Electrify America has contracted with the charging infrastructure support company Hubject to implement support for the “Plug & Charge” mechanism that is a standard part of the CCS charging protocols.
Drivers with a car configured for this new mechanism can charge with the simplicity of a Tesla car at a Supercharger location — just plug in the car and walk away without needing an RFID card or a smartphone app to first start and authenticate the charging session.
Hubject is a German company best known in Europe for operating a clearinghouse that allows customers of one charging provider to use charging equipment from other providers using a single account much like holders of bank ATM cards can get cash at an ATM operated by another bank. Hubject has previously received investments by several European automakers including Volkswagen, the parent company of Electrify America.
Hubject has been quietly toiling away as a leading developer of the infrastructure and support that will be needed by automakers and charging providers to implement “Plug & Charge” (sometimes known as PnC).
The PnC mechanism is defined in the ISO 15118 standards that are a core part of CCS but it has not been utilized yet because it requires an automotive version of the same type of cryptographic mechanisms used to secure the Internet. The infrastructure needed to support deployment of the PnC system required further development and wasn’t fully tested and ready until recently.
Last year, the Smart division of Mercedes Benz became the first automaker to announce support for PnC on its small EVs. VW Group has also announced support for PnC in its forthcoming vehicles such as the Audi e-tron and Porsche Taycan.
Other car makers have not yet announced support including Jaguar, Hyundai and Kia, or General Motors.
In order to use PnC, a vehicle must have a unique public key certificate issued and installed very similarly to how a secure website needs a certificate and matching private key to have an “https” URL that authenticates its identity to users and their browser software. The PnC certificates are based on the same X.509 standard used for Internet website certificates.
Likewise, the CCS charging equipment would have its own public key certificate and private key to authenticate itself to the car.
Before using a charger with PnC the car owner must first establish an account with an “eMobility charging provider”. This might be one of the existing charging provider companies or an automaker might optionally take on this role as part of its ongoing relationship with its customers. It’s believed that Audi and Porsche may choose to become mobility charging providers.
The customer creates an account with the mobility charge provider of their choice using configuration screens in the car and this creates a new public key certificate that represents a charging service contract between them and the mobility provider. A car dealer could assist in configuring this at the time of vehicle sale.
With all of this in place, a driver can arrive at a charger, perhaps at an Electrify America site, and plug in their car. This would automatically result in their car creating a TLS (also known as SSL) connection to the charging station almost exactly the way a browser would connect to a website with an https URL.
The actual communications involved are very much like a web transaction because CCS sets up a private network between the charger and the vehicle based on the same Internet protocol standards like TCP, UDP, IP, and TLS that are used between a home Internet router and your home’s network-connected computers and other devices.
The lowest-level transfer mechanism used to send the data packets between the car and charger uses a simplified and limited version of the “HomePlug Green PHY” power line communications standard that can be used to connect your home’s networked devices over regular room power outlets instead of using WiFi or Ethernet.
In the case of CCS, these data signals aren’t actually sent over the charging power pins but are instead sent over the small low voltage “Control Pilot” signaling pin inside the upper part of the J1772 connector.
The CHAdeMO charging standard used by the Nissan LEAF and some other Asian cars uses different networking standards known as “CAN bus” or Controller Area Network bus. This standard was originally designed for factory floor computers and is often used for interconnecting the various internal computers and controllers within a car. The CHAdeMO Association, which oversees the standards process, has said they are working on a Plug and Charge mechanism with similar capabilities.
A major downside of the ISO PnC mechanism is that it requires additional hardware and software support from automakers and is likely to not be supported on older car models already in use. When a car that does not support PnC is plugged in, the charging dispenser will ask for a credit card or other payment authorization as it does today.
A different mechanism known as Autocharge has been developed by charging equipment vendor ABB. It is the underlying framework used for the Plug and Charge mechanism already supported by the Fastned charging provider company in Europe. Other charging providers such as EVgo have said in the past that they reviewed it and decided not to integrate support for it.
Update: EVgo announced in April 2019 that it intends to support the Autocharge mechanism in the near future.
Autocharge uses an “EV-ID” identifier assigned to cars by auto makers in a proprietary format to uniquely identify individual vehicle. The identifier can be queried using the standard CCS charging protocol. This system can be used with many existing cars already on the road but may not scale as well as the ISO PnC mechanism and is not as secure.
In a recent interview, Electrify America’s Chief Operating Officer, Brendan Jones, said his company is not actively looking at supporting Autocharge and is focusing on implementing the ISO PnC mechanism.
The ISO PnC mechanism can technically be used with AC J1772 charging as well but AC charging equipment is less expensive and uses simpler internal electronics that usually only implement older analog signaling protocols rather than the Internet-based standards needed by PnC.
Most new-generation DC CCS chargers are specified as being capable of supporting ISO 15118 PnC even if they haven’t been provisioned yet with the necessary public key certificates and software updates needed to support it.
Among other things, Hubject is acting as a public key certificate authority or CA for the automotive PnC industry.