Improvements in or relating to electric vehicle charging

Abstract

A charging process for an electric vehicle (EV), comprising: i) physically connecting an AC charging cable plug to an AC socket of an EV; ii) initiating a direct current (DC) charging session so as to commence high level communications (HLC); and iii) closing the DC charging session.

Description

[0001] IMPROVEMENTS IN OR RELATING TO ELECTRIC VEHICLE CHARGING

[0002] The present disclosure relates generally to electric vehicles (EV) and particularly, although not exclusively, to processes and protocols for charging electric vehicles.

[0003] The EV charging supply equipment industry is currently split into two main categories: alternating current (AC) and direct current (DC) charging. Each have their own characteristics, with AC charging designed to be cheaper and more easily installed but with slower charging rates, and DC charging providing higher charging rates but with more bulky and expensive equipment.

[0004] The power available from the grid, is AC. However, all vehicle batteries can only store electricity with a direct current. Therefore AC chargers, which supply AC electricity to the vehicle, rely on an onboard converter on the vehicle to convert AC to DC. DC chargers will convert AC to DC within a charge station unit and then offer DC electricity to the vehicle. This is illustrated in Figure 1 .

[0005] EV charging is highly standardised, and the standards are primarily focused on safety and connectivity. The standards vary between regions. However, one common thread is the availability of separate standards for AC and DC charging.

[0006] The original standard for EV charging laid out two very different means of communication with the vehicle depending on whether AC or DC charging is being used.

[0007] The IEC 61851 - Electric vehicle conductive charging system standard defines the characteristics of on-board and off-board equipment for charging electric road vehicles at standard AC supply voltages up to 1000 V and at DC voltages up to 1500 V.

[0008] The standard defines different charging modes (both AC and DC) for charging the Electric Vehicle (EV). These modes are:

[0009] • Charging Mode 1 - AC charging, EV to mains over standard 1 ph / 3ph sockets. Up to 16 A and 250 / 480 V. No protection device in the charging cable.

[0010] • Charging Mode 2 - AC charging, EV to mains over standard 1 ph / 3ph sockets. Up to 32 A and 250 / 480 V. Protection device integrated in the charging cable.

[0011] • Charging Mode 3 - AC charging using dedicated AC charging stations. Mandatory PWM signalling and optional High Level Communication (HLC)

[0012] • Charging Mode 4 - DC charging using dedicated DC charging stations. Mandatory PWM signalling and mandatory High Level Communication (HLC)

[0013] The standard then breaks down the Charging Mode 4 into 3 Systems. These systems differ in both HLC and connector used. These systems are:

[0014] • System A - The physical / data layer is through CAN bus A interface while the application layer is defined in I EC 61851-24 standard.

[0015] • System B - The physical / data layer is through CAN bus B interface while the application layer is defined by the GB / T 27930 standard.

[0016] • System C - The physical / data layer is through Power Line Communication (PLC) while the application layer is defined by the ISO 15118-2 Protocol.

[0017] Low-level communication protocols used by AC chargers

[0018] AC smart chargers and electric vehicles are engaged in a constant exchange of information using pulse width modulation (PWM). Communication between them is defined by the I EC 61851-1 standard among others as described above. The following are the normal operation parameters and states expected to be seen in an AC charging session. As can be seen the information exchange between an EV and an AC charger is very limited.

[0019] Signal voltages alternate between different levels to indicate the charging state:

[0020] • +12 V State A No EV connected to the EVSE

[0021] • +9 V State B EV connected to the EVSE but not ready for charging

[0022] • +6 V State C Connected and ready for charging, ventilation is not required

[0023] • +3 V State D Connected, ready for charging, and ventilation is required • +0 V State E Electrical short to earth on the controller of the EVSE, no power supply

[0024] • -12 V State F EVSE is unavailable

[0025] The information provided by the duty cycle (effectively pulse width) of the PWM signal defines the maximum charge delivered to the EV:

[0026] • Duty cycle < 3 % No charging allowed

[0027] • 3 % < duty cycle < 7 % Force high-level communication protocol according to ISO 15118 or DIN 70121

[0028] • 7 % < duty cycle< 8 % No charging allowed

[0029] • 8 % < duty cycle< 10 % Max. current consumption for AC charging is 6 A

[0030] • 10 % < duty cycle < 85 % Available current = duty cycle * 0.6 A

[0031] • 85 % < duty cycle < 96 % Available current = (duty cycle - 64) * 2.5 A

[0032] • 96 % < duty cycle < 97 % Max. current consumption for AC charging is

[0033] 80 A

[0034] • Duty cycle > 97 % No charging allowed

[0035] DC charging communication protocols

[0036] DC chargers must work intelligently to charge and protect the battery. There are two communication levels: high level and low level as described above. International standards such as IEC 61851 , ISO 15118, DIN 70121 and VDV 261 provide the basis for the contact between the charging station and the vehicle before and during the charging process.

[0037] Low-level communication protocols manage the max current and the charging stage. High-level protocols manage more complex tasks, such as assessing compatibility, charging sequence, establishing physical limits, and managing tariffs and payments.

[0038] There are three high-level communication protocols:

[0039] 1. Power Line Communication (PLC) -This is the high-level communication framework used in CCS1 and CCS2. It uses a standard TCP / IP stack (Transmission Control Protocol I Internet Protocol) for communicating.

[0040] 2. Signal Level Attenuation Characterization (SLAC) - The vehicle and charging station agree on a unique identifier based on a requestresponse process. SLAC is used in an environment where multiple electric vehicles and charging stations are interconnected, such as a vehicle depot.

[0041] 3. Controller Area Network (CAN) - CAN is defined by the ISO 11898 standard and is a message-oriented platform used to power quick information exchange between control units in an industrial setting.

[0042] Aspects and embodiments of the present invention may be based around the

[0043] PLC communication framework, i.e. system C as defined above. The ISO 15118-2 Standard Protocol is responsible for defining the digital communication layer between the EV and EVSE for the DC charging mode when System C is applied.

[0044] ISO 15118-2 Protocol

[0045] ISO 15118-2 (Road Vehicles - Vehicle to grid communication interface) specifies the digital communication protocol between Electric Vehicles (EV) and the Electric Vehicle Supply Equipment (EVSE). The communication parts of this generic equipment are the Electric Vehicle Communication Controller (EVCC) and the Supply Equipment Communication Controller (SECC), ISO 15118-2 describes the communication between these components.

[0046] Although ISO 15118-2 is oriented to the charging of electric road vehicles, it is open for other vehicles as well. As part of the Combined Charging System (CCS), ISO 15118-2 covers wired (AC and DC), wireless charging applications and enables the integration of EVs into the smart grid (V2G - vehicle-to-grid).

[0047] ISO 15118-2 allows the EV and charging station to dynamically exchange information based on which a proper charging schedule can be (re-)negotiated. Smart charging applications calculate an individual charging schedule for each EV by using the information available about the state of the electrical grid, the energy demand of each EV, and the mobility needs of each driver (departure time and driving range). This way, each charging session perfectly matches the capacity of the grid to the electricity demand of simultaneously charging EVs.

[0048] ISO 15118-2 also comes with a feature called Plug & Charge. Plug & Charge deploys several cryptographic mechanisms to secure this communication and guarantee the confidentiality, integrity, and authenticity of all exchanged data. This is achieved by using the Transport Line Security (TLS) protocol.

[0049] The ISO 15118-2 digital communication implements the following features:

[0050] • security concept including encryption, signing, key management, etc.

[0051] • robust PLC-based communications

[0052] • automatic address assigning and association

[0053] • IPv6-based communications

[0054] • compressed XML messages

[0055] • client-server approach

[0056] • safety concept including cable check, welding detection, etc

[0057] • extension concept for added-value services

[0058] According to the protocol, the EV charging process is separated into eight functional groups as shown in Figure 2.

[0059] Message sequence for an ISO 15118-2 DC charging session

[0060] The charging process for a DC charging session carried out by ISO 15118-2 is illustrated in Figure 3. The entities that carry out certain actions, such as sending or receiving messages and opening or closing contactors, are illustrated in the boxes at the top. States A, B, and C relate to certain voltage levels measured by the charging station and are defined in IEC 61851. ISO 15118-2 builds and expands on IEC 61851 and enables digital communication between EVCC and SECC, which starts as soon as the duty-cycle of the pulse width modulation (PWM) signal is set to 5%, as defined in IEC 61851.

[0061] The above demonstrates the difference between communications in normal AC and DC charging and although ISO 15118 allows for High Level Communications on AC chargers it has not been implemented by chargepoint manufacturers or vehicle manufacturers.

[0062] The present invention seeks to provide improvements in or relating to electric vehicle charging.

[0063] Some aspects and embodiments are based on one or more existing, stand ards / protocols (e.g. IEC 61851) which are modified to provide high level communications as part of an AC charging session.

[0064] A temporary, non-standard DC current charging session may be initiated.

[0065] An aspect of the present invention provides an AC charging session protocol for an electric vehicle (EV), comprising initiating a direct current (DC) charging session so as to commence high level communications (HLC). An aspect of the present invention provides a charging process / protocol for an electric vehicle (EV), comprising: i) physically connecting an AC charging cable plug to an AC socket of an EV; ii) initiating / causing a direct current (DC) charging session so as to commence high level communications (HLC); and iii) closing the DC charging session.

[0066] The present inventors have identified that in many settings (e.g. fleets and depots) being able to identify the vehicle being charged and also access to state of charge and basic battery information in AC-based charging infrastructure would be of enormous benefit to the operator in terms of fleet management and also assist with better charging optimisation and prioritisation.

[0067] The process may include a step of interrogating / accessing / acquiring HLC information. Information may include one or more of: identify the vehicle being charged; state of charge; battery information.

[0068] The process may further comprise physical and / or virtual disconnection of the socket to cause a vehicle reset.

[0069] Processes in accordance with the present invention may further comprise initiating an AC charging session. The AC charging session is initiated before step ii) and / or after step iii), for example. The temporary, non-standard DC current charging session may be initiated by setting the PWM signal duty cycle to 5%.

[0070] An example of a protocol is: initiate DC or AC charging initiate DC charging shut down DC charging initiate AC charging

[0071] An example of a protocol is: startup sequence startup DC interrupt start AC charging

[0072] Some protocols use an AC chargepoint and use a temporary DC protocol so as to interface with the AC charger to get information from a connected vehicle. The EV “thinks” it is in a DC charging scenario. The EV is artificially placed into a DC state.

[0073] A further aspect may provide a retrofit unit comprising hardware, software and communications ability to simulate DC charging communications for use with existing AC chargepoints. The unit may, for example, comprise an adapter device that can plug into a socket and sit between an existing socket and a charging cable to mimic the layout of an existing charging socket.

[0074] High level communications electronics may be contained within the socket adapter.

[0075] The socket adapter may contain control circuitry to intercept and manage the control pilot signal between the adapter and the vehicle and the adapter and the charger.

[0076] In some embodiments the socket adapter can manage communications to a cloud platform via a secure wireless connection to a local proprietary data collector that receives information from a plurality of such local adapters.

[0077] The present invention also provides a hardware device that can be installed within an AC chargepoint and connected to the control pilot wire within the chargepoint.

[0078] The ability to communicate using HLC is built into all vehicles capable of DC charging (almost all vehicles have this capability). The communications pin on the standard socket is the same for AC charging as it is for DC charging and is called the Control Pilot (CP). The CP is one of five pins on a type 1 connector and one of seven pins on a type 2 connector. Control pilot pins are used in EV charging cables to negotiate current charging levels and pass information from the electric vehicle to the electric vehicle charger. The proximity pilot (PP) pin works by signalling to the electric vehicle charger that the charging cable is securely connected and receiving power. If the connector is not connected properly the proximity pilot will disable charging and stop sending power to the vehicle as a safety precaution.

[0079] Figure 4: IEC 62196 Type 2, for example. Female (vehicle connector) Combo2 - DC Charger (left) and Normal Type 2 - 1-3 phase AC Charger (right). Figure 5: CCS Plug and corresponding socket shown with connectors labelled. Note that the Control Pilot (CP) and Proximity Pilot (PP) pins are in same location.

[0080] AC charging communication protocols

[0081] Some embodiments of the present invention are based on the idea that it is possible for an AC charger to force high level communications, for example by initiating a 5% duty cycle as described above.

[0082] At the moment AC charging has no information about state of charge or vehicle ID but very basic handshake communications with the vehicle about the available charging capacity of the charge point.

[0083] In numerous customer settings, having some form of vehicle ID and also access to state of charge information would be of enormous benefit to the customer and also assist with better charging optimisation and prioritisation.

[0084] This allows the retrieval of information at the beginning of the charge by “tricking” the vehicle into thinking it is dealing with a DC charger. It then switches back to AC charging mode to be an AC charger; therefore it would not be able to retrieve information during the charge session. It is, however, possible to retrieve information again at the end of the charge.

[0085] Initiating high level communications indicates the start of a DC charging session.

[0086] Some embodiments provide or relate to AC charging vehicle communications.

[0087] Some embodiments use as a basic premise that it is possible for an AC charger using a type 2 connector to force high level communications with the vehicle using the same Control Pilot pin by initiating a 5% duty cycle.

[0088] This protocol allows the identification of the vehicle and retrieval of information at the beginning of the charge by switching the vehicle into HLC mode. In an embodiment a system initiates the High Level Communications, retrieves the required information, safely stops the HLC session and then reverts back to low level comms to begin a normal AC charging session. It will not be possible to retrieve information during the charge as the existing AC charging standard that both vehicles and charge points conform to does not allow for this. It would, however, be possible to retrieve information again at the end of the charge.

[0089] It is known that AC charging vehicle high level communications are part of the newer ISO 15118 standard, although this will require implementation by both charger manufacturers as well as vehicle manufacturers both requiring hardware and software redesign to meet the standard. However, there are many millions of legacy chargepoints and vehicles that will not meet this new standard.

[0090] Implementation of the present invention may be achieved be using modified software on existing or new hardware (which may also have the required HLC hardware built in).

[0091] The communications hardware within the electric vehicle supply equipment (EVSE) may include the PWM generator for AC charging control and the Homeplug Green PHY hardware layer that enables the PLC communications. Both of these may be connected to the Control Pilot wire. The software stack may include the ISO 15118-2 protocol communications layer. However, the procedural / process level software may be written to first initiate the DC charging and High Level Communications steps before then closing the HLC session and reverting back to the standard AC charging protocol. In this way the present invention is a new method for using and combining the existing standards on older hardware. An example charging protocol is illustrated in Figure 6.

[0092] Referring to the diagram excerpt from BS 15861 (Figure 7) the relevant information can then be received.

[0093] At this stage the HLC comms can be ended (for example as illustrated in Figure 8).

[0094] The present invention also provides a modular retrofit unit that contains the relevant hardware, software and communications ability to simulate DC charging communications that could be used with existing legacy AC chargepoints to provide the same identification functionality.

[0095] This could take the form of a device that can plug into the socket and would sit between the existing socket and the charging cable, for example as shown in Figure 9. This would mimic the layout of an existing charging socket.

[0096] The high level communications electronics are contained within the socket adapter. The socket adapter (which may be known as an ACID adapter) also contains the relevant control circuitry to intercept and manage the control pilot signal between the ACI D adapter and the vehicle and the ACID adapter and the charger. The socket adapter may manage communications back to a cloud platform via a secure wireless connection to a local proprietary data collector that receives information from all local adapters.

[0097] An alternative form of this device comprises a hardware device that can be installed within an AC chargepoint and connected to the control pilot wire within the chargepoint. Its means of operation could then be as described above.

[0098] Aspects and embodiments of the present invention may be used in conjunction with the Applicant’s charging system described in PCT / EP2024 / 066703, the contents of which are hereby incorporated by reference.

[0099] Example embodiments are described herein in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein.

[0100] Accordingly, while embodiments can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included.

[0101] The terminology used herein to describe embodiments is not intended to limit the scope. The articles “a,” “an,” and “the” are singular in that they have a single referent, however the use of the singular form in the present document should not preclude the presence of more than one referent. In other words, elements referred to in the singular can number one or more, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and / or “including,” when used herein, specify the presence of stated features, items, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, items, steps, operations, elements, components, and / or groups thereof.

[0102] Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealised or overly formal sense unless expressly so defined herein.

Claims

CLAIMS1 . A charging process for an electric vehicle (EV), comprising: i) physically connecting an AC charging cable plug to an AC socket of an EV; ii) initiating a direct current (DC) charging session so as to commence high level communications (HLC); and iii) closing the DC charging session.

2. A process as claimed in claim 1 , further comprising physical and / or virtual disconnection of the socket to cause a vehicle reset.

3. A process as claimed in claim 1 or claim 2, further comprising initiating an AC charging session.

4. A process as claimed in claim 3, in which the AC charging session is initiated before step ii) and / or after step iii).

5. A process as claimed in any preceding claim, in which the DC current charging session is initiated by setting the PWM signal duty cycle to 5%.

6. A modular retrofit unit comprising hardware, software and communications ability to simulate DC charging communications for use with existing AC chargepoints.

7. A unit as claimed in claim 6, in which the unit comprises an adapter device that can plug into the socket and sit between an existing socket and a charging cable to mimic the layout of an existing charging socket.

8. A unit as claimed in claim 7, in which high level communications electronics are contained within the socket adapter.

9. A unit as claimed in claim 7 or claim 8, in which the socket adapter contains control circuitry to intercept and manage the control pilot signal between the adapter and the vehicle and the adapter and the charger.

10. A unit as claimed in any of claims 7 to 9, in which the socket adapter can manage communications to a cloud platform via a secure wireless connection to a local proprietary data collector that receives information from a plurality of such local adapters.

11. A hardware device that can be installed within an AC chargepoint and connected to the control pilot wire within the chargepoint.

12. An AC charging session protocol for an electric vehicle (EV), comprising initiating a temporary, non-standard DC charging session so as to force high level communications (HLC).

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