NL2031706B1 - A high-voltage direct current circuit for an electric vehicle with a secondary relay - Google Patents

Abstract

A. high—voltage direct current circuit comprising a secondary relay comprising a control means for allowing external control of the relay and for reversibly deactivating said secondary relay. Said secondary relay is assembled with the circuit or the main relay for triggering said main relay to disconnect the engine from the battery pack upon deactivation of the secondary relay. The secondary relay is separate from the at least one charge relay, the pre—charge relay and the at least one auxiliary relay.

Description

A high-voltage direct current circuit for an electric vehicle with a secondary relay

The invention relates to a high-voltage direct current circuit for feeding electrical energy from a high-voltage battery pack to an electric engine, wherein the circuit comprises a main relay for shutting off electrical power from said battery pack to said engine; at least one charge relay; a pre-charge contactor relay; and at least one auxiliary relay.

Furthermore the invention relates to an electric vehicle comprising such a circuit, a charging station and a safety plug.

In present electric vehicles the high-voltage direct current circuit comprises a variety of relays. Each relay governs particular aspects of the circuit. These functions will be discussed herein below:

A pre-charge contactor relay is comprised in the high- voltage circuit to protect main contactors from an excess inrush of current, a pre-charge contactor is used together with a pre- charge resistor to charge capacitors of a power inverter to a level of typically 90-98% of the battery voltage.

A charger contactor relay is comprised in the high-voltage circuit to establish a connection between the battery charger and the traction battery when the vehicle is connected to a charging station. This may include quick charge and normal charge relays.

Auxiliary contactor relays are comprised in the high- voltage circuit for controlling electrical loads, other than the engine, in the vehicle that are operated by the high-voltage battery. This could be an electric heater, a blower, an A/C compressor, a pneumatic brake compressor, power steering pump, and so on and so forth.

Lastly a Main Relay is comprised in the high-voltage circuit in both the positive and negative lines of the traction battery, also known as the high-voltage battery pack. The main contactors connect and disconnect the traction battery from the entire electric drivetrain of the vehicle. The main relay is thus, in plain English, able to disconnect the high-voltage battery from the engine of the vehicle. This main relay is the most important safety feature of the high-voltage circuit. The

- 2 = main relay is usually connected to a battery management system which is designed to disconnect the engine from the battery when the battery shows signs of malfunction. This in turn prevents an electric vehicle from performing what is known as auto- locomotion. While the battery management system usually disengages the main relay after a crash there are circumstances in which this may fail. Such circumstances include a situation in which the management system or its sensors incur extensive damage and can no longer perform reliably. Such circumstances may also include situation of minor damage, like fender benders.

In the latter situation there may not be cause for the battery management system to disengage the drive train. However, drivers may exit the vehicle shaken and forget to power down the vehicle.

This means that first responders arriving to the scene of an accident cannot be sure that a vehicle will not start moving of its own accord. First responders tend to not have easy access to the cabin of a vehicle, as they generally do not have the keys to the vehicle. In some situations the cabin or internal display systems may also be damaged. Thus, further disallowing first responders from confirming that a vehicle has indeed powered down. It also prevents first responders from recognizing a potential battery malfunction in a timely manner. As such, it is a frequent occurrence that a vehicle was left powered on during salvaging or rescue operations. It goes without saying that this presents a high risk of injury to first responders and is highly disadvantageous to any salvaging or rescue operations.

It is an aim of the present invention to amend the high- voltage system such and to provide the first aid responders with easy means to ensure that the vehicle will not start driving of its own accord.

To this end the invention provides a high-voltage direct current circuit characterized in that the circuit further comprises a secondary relay comprising a control means for allowing external control of the relay and for reversibly deactivating said secondary relay, and wherein said secondary relay is assembled with the circuit or the main relay for triggering said main relay to disconnect the engine from the battery pack upon deactivation of the secondary relay, wherein the secondary relay is separate from the at least one charge

- 3 = relay, the pre-charge relay and the at least one auxiliary relay.

It is to be understood that external control is given to mean that the controller responds to an instruction signal from outside of the electrical circuit. By addition of this feature the high-voltage circuit becomes controllable through external instruction, which may be used by first responders to disconnect the drive train from the battery. It is noted that a control means may simply be a processor, wherein the secondary relay comprises actuation means which are controlled by said processor. Preferably, the secondary relay 1s arranged to prevent the main relay from restoring electrical power to the engine when, in use, the secondary re-lay is in the deactivated state. It is noted that the main relay requires to be powered constantly in order to sustain the high-voltage connection between the engine and the battery. To this end the secondary relay may be provided to an electrical feed line that of the main relay so as to allow the secondary relay to interrupt electricity to the main relay. The person skilled in the art will understand that this is but one of a myriad of possible arrangements. In yet another example the secondary relay may be arranged in both the positive and negative lines of the battery to the engine. In a sense the secondary relay would, in such an example, act as a second main relay. A benefit of any such design is that the main relay cannot unexpectedly be restored as a side-effect of any tinkering to the vehicle. For the sake of clarity it is also noted that the secondary relay be assume either one of an activated and deactivated state at any given time. In the deactivated state the main relay, and thus power to the engine, is interrupted, in the activated state the main relay, and thus power to the engine, is left uninterrupted.

Opticnally, the secondary relay comprises a sender-receiver for wireless communication and arranged for being remote controlled, such as via a wireless network. Exemplary the sender-receiver may be designed to operate on a mobile network such as a phone network 2G, 3G, 4G, 5G, WiFi, Bluetooth. This beneficially enables first responders to disconnect the drive train without needing to touch or be near the vehicle. Alternatively, and or additionally, the secondary relay may be arranged for being controlled over a CAN-bus of the vehicle or over a pilot contact,

such as a proximity pilot or control pilot contact. This beneficially reduces the need for additional parallel infrastructure. Optionally, the circuit has a sensor that is arranged with the main relay for detecting a state of the main circuit. The sensor is designed for a signaling the state of the main circuit over a pilot contact, a CAN-bus or over a wireless network. The state may be understood as being activated or deactivated. That is to say that the main relay is always in a state in which it locally closes or opens the circuit. The sensor may present itself as a volt-meter that measures on the circuit over a portion of the relay in either the positive or negative line. Alternatively the sensor may be a switch, that is open when the main relay is open, and closed when the main relay is closed, or vice versa. In the example where the sensor presents a signal to a pilot contact the sensor is communicatively connected to a pilot line, such as a control pilot or proximity pilot line. It is noted that any pilot line terminates in a pilot contact at charging port. This means that the signal will be detectable through measurement at the charging port.

Alternatively, the sensor may be communicatively connected to the CAN-bus or the sender-receiver of the secondary relay for wirelessly transmitting the state of the main relay. This allows external devices to the vehicle from safely determining whether the vehicle is prevented from auto-locomotion. In yet another embodiment the sensor is comnunicatively connected to the CAN- bus, in which case its signals can be picked up and processed by the vehicle’'s CPU, BMS or other systems.

In one example the second relay may comprises a receiver for reversibly deactivating in response to a signal that is superimposed over a pilot signal, such as a proximity pilot or control pilot signal, and entered via a charge port. To this end the receiver is communicatively connected to the control means.

Said receiver would be different from any senser-receiver for wireless communication if also present. This allows a single charge port manipulation, or better yet a single combined pilot line signal at the charge port, to trigger the vehicle to simultaneously brakes and to disconnect the drive train.

Optionally, the secondary relay has an electric power source, such as a low-voltage power source, external to the

— 5 = high-voltage circuit, wherein reversing deactivation of the secondary relay is powered by the electric power source that is external to the high-voltage circuit. Low-voltage is here between 9-50 V, preferably 12 V. Wherever high-voltage is mentioned a voltage of 400 V and up is to be understood. Any senser-receiver or receiver associated with the secondary relay would here also be powered by the low-voltage power source.

According to a second aspect of the invention there is provided an electric vehicle comprising a charging port; a battery pack; an electric engine; and the circuit according to the first aspect of the invention and any subsequent feature.

According to a third aspect of the invention there is provided a charging station for charging an electric vehicle according to the second aspect of the invention via its charging port. The station comprises a communication portion for communicating with the secondary relay for reversibly deactivating said secondary relay. Such a communication portion may comprise a circuit for superimposing an instruction signal over a pilot signal, wherein the signal is provided to the vehicle through the charge port connection between station and vehicle. In such an example the second relay is communicatively connected to charge port via a pilot line, such as the proximity pilot or control pilot line, which terminate at the charge port.

Optionally, the secondary relay comprises a sender-receiver for wireless communication and arranged for being remote controlled, and wherein the communication portion also comprises a sender- receiver, and wherein the communication portion communicates wirelessly with the secondary relay for the deactivation thereof. Further optionally, the communication portion is communicatively connected to a sensor that detects the status of the main relay, and wherein the communication portion further communicates the status of said relay. The secondary relay may alternatively or additionally be arranged for being controlled over a CAN-bus of the vehicle. The sender-receiver of the secondary relay is in such an example connected to said CAN- bus. This is preferably the same CAN-bus to which the battery management system is connected.

As mentioned the secondary relay may be controlled over a pilot contact, such as a proximity pilot or control pilot contact, and wherein the secondary relay comprises a receiver for reversibly deactivating in response to an instruction signal that is superimposed over a pilot signal, such as a proximity pilot or control pilot signal, and wherein the communication portion of the station is designed to superimpose the instruction signal over said pilot signal.

According to a fourth aspect of the invention there is provided a charge port plug designed for shielding the electrical contacts of the vehicle against charging, and comprising an electrical circuit that connects with a pilot contact, such as a proximity pilot or control pilot contact, of the charging port of the vehicle, and wherein the plug is designed to send an instruction signal to the vehicle via the pilot contact. The electrical circuit may also here be designed for superimposing the instruction signal over a pilot signal, such as a proximity pilot or control pilot signal. However, there may also be other ways of sending instructions to the secondary relay. For example, the circuit may instead or additionally comprises a wireless sender-receiver for sending the instruction signal to the vehicle and for receiving information from the vehicle. This information may pertain to the status of the main relay. In yet another option the plug may be designed to be controllable via a paired device, such as a human interface, for sending the instruction signal, or comprises a manual switch {for sending the instruction signal.

To this end the plug would comprise a sender-receiver.

According to a fifth aspect of the invention there is provided a pilot line signal for an electric vehicle, in particular a charging port of the electric vehicle, comprising: a first signal being one of a proximity pilot signal and control pilot signal; and a second signal superimposed on the first signal. Pilot signals encode information in their pulse-width, frequency and amplitude. A pilot line signal of this kind, presented to a charging port of a vehicle, may therefore emulate connection to a charging station while simultaneously propagating a hidden signal deeper into the electric infrastructure of the vehicle. Preferably, the second signal has a frequency in the range of 100kHz to 10 MHz, which is at least one order of magnitude higher than the signal frequency of the

- 7 = first signal, which is usually 1kHz, but may vary between 0.5 and 10kHz. This allows the second signal to be transposed without changing the manner in which the first signal is read by the

BMS. Further optionally, the second signal may encode digital data along the loop conductors in the form of AC signals superimposed on first signal. In closing, the second signal would here comprise the instruction to deactivate a relay in the high-voltage circuit of the electric vehicle.

The invention is further elucidated by a number of Figures which show a portion of the high-voltage circuit of the vehicle:

Fig. 1 shows the HV-circuit according to the prior art;

Fig. 2 shows a first embodiment of the HV-circuit of the invention;

Fig. 3 shows a second embodiment of the HV-circuit of the invention;

Fig. 4 shows a third embodiment of the HV-circuit of the invention;

Fig. 5 shows a fourth embodiment of the HV-circuit of the invention;

Fig. 6 shows a fifth embodiment of the HV-circuit of the invention;

Fig. 7 shows a sixth embodiment of the HV-circuit of the invention;

Fig. 8 shows a seventh embodiment of the HV-circuit of the invention; and

Fig. 9 shows an eighth embodiment of the HV-circuit of the invention.

Figure 1 shows the high-voltage circuit 100 of a vehicle according to the prior art schematically. In the prior art the high-voltage circuit 100 has a high-voltage battery pack 101, of at least 400 V, which feeds an electric engine 102 of the vehicle via an inverter 102.1. The circuit has a main relay 1 for shutting off electrical power from said battery pack to said engine. The main relay 1 is here provided in both the positive and negative feed line of the battery to the engine, and therefore appears twice in the high-voltage circuit. However, the main relay is designed as a singular device connecting with both the positive and negative feed lines. Which line is the positive and which line is the negative feed line can easily be derived from the polarity of the battery 101 as drawn. Besides a main relay at least one charge relay CR is provided as well as a pre-charge contactor relay PCR; and at least one auxiliary relay AR. In Figure 1 quick-charge relays are indicated with an

Asterix *. Auxiliary relays are part of the high-voltage circuit for controlling electrical loads, other than the engine, in the vehicle that are operated by the high-voltage battery pack 102.

The high-voltage battery pack itself is provided with at least one fuse F. Electrical loads, other than the engine are indicated with the term AUX. Furthermore the high-voltage circuit 100 shows a main capacitor C, and a resistor R associated with the

PCR. A current rectifier AC/DC, or other alternating current (AC) to direct current (DC) converters are provided for charging the high-voltage battery pack 101 by connecting the vehicle for charging to an AC power source, such as a domestic power outlet.

A charging station CS can be schematically seen as a matter of example connected to a charging port 100.1. The highlighted portion -.-.-.- is going to be a matter of further focus, as this portion is adapted in the invention.

Figure 2 shows a part of the high-voltage circuit 100A according to the invention. The portion that is focused on coincides with the -.-.-.- highlighted portion on Figure 1. Here the relays CR and AR have not be shown, even if they are present in the larger circuit. Hereinafter only the main relay 1 and a secondary relay 2 are focused on. This secondary relay comprises a control means 3 in the form of a processor which controls the actuation of the relay. The control means is associated with a transponder TP, a form of sender-receiver, for wireless communication with an external device ED, such as a human interface. In this example the external device is indeed a human interface in the form of a tablet, laptop or smartphone. Such a device may be paired with the secondary relay. That is to say, be designed to exclusively process instructions, such as by an instruction signal, sent by that particular external device over a wireless network i. In this example the main relay 1 is designed to be reversibly deactivated said secondary relay 2 in an electronic cascade, wherein the deactivation of the secondary relay causes the deactivation of the main relay. To this end the secondary relay is assembled with one of the electric feed lines to the main relay. The secondary relay and its controller and transponder are here each powered by a low voltage external power source EP, such as the 12 V car battery system that is present alongside the high-voltage battery pack. Additionally, a sensor, in this example a voltage meter V, is provided over a portion of one of the feed lines between the high voltage battery pack 101 and the electric motor 102. The portion over which measurement takes place comprises a point before and a point after the main relay in said same feed line. The voltage meter is communicatively connected to the transponder TP via the control means 3. The control means are here designed to either transmit the measurements of the voltage meter V to the external device ED or to determine the state, open or closed, of the main relay 1 and to transmit that information. It is noted that the sensor is optional. This is indicated with a dashed line ----- . The addition to the circuit according the invention is indicated with -.-.-.- line. A current sensor C may also be present. This sensor would otherwise already be present in the high-voltage circuit 100A, but may here be communicatively connected to the controller to transmit measurement information.

However, this is entirely optional.

Figure 3 shows a second embodiment of the circuit 100B according to the invention. Hereinafter only differences are discussed with respect to the first embodiment of the circuit 100A according as shown in Figure 2. Same features carry the same reference signs. The second embodiment differs in that the sensor is provided as an auxiliary contact AX, which is basically a switch that itself opens or closes a separate circuit from which the, opened or closed state of the main relay can be determined. This separate circuit is also powered by the external power source EP.

Figure 4 shows a third embodiment of the circuit 100C according to the invention. Hereinafter only differences are discussed with respect to the first embodiment of the circuit 100A according as shown in Figure 2. Same features carry the same reference signs. In this second embodiment there is no transponder. Instead the control means 3 is communicatively arranged to a pilot line PL, such as the proximity pilot or control pilot line. The pilot line terminates at the charging

- 10 = port (not shown, but customary). In this example a charge port plug P may be provided with a sender-receiver (not shown, but customary) and attached to the charging port. Such a plug would allow sensor information to be communicated to an external device. Additionally, the plug may comprise a communicator (not shown, but customary) for communicating instruction signals over the pilot line PL to the control means 3. The secondary circuit may in this example be controlled via the plug or external control means. Alternatively, the plug itself comprises a display, or LED lights for communicating sensor information, as well as a manual switch to allow a user to control the sending of electric instruction signals over the pilot line to the secondary relay. The external device, as well as the sender- receiver of the plug are therefore merely optional features in this embodiment. In a sense, the plug P itself may serve as an external device by which the secondary relay can be controlled.

Figure 5 shows a fourth embodiment of the circuit 100D according to the invention. Hereinafter only differences are discussed with respect to the third embodiment of the circuit 100C according as shown in Figure 4. Same features carry the same reference signs. The fourth embodiment differs in that the sensor is provided as an auxiliary contact AX, which is basically a switch that itself opens or closes a separate circuit from which the, opened or closed state of the main relay can be determined. This separate circuit is also powered by the external power source EP.

Figure 6 shows a fifth embodiment of the circuit 100E according to the invention. Hereinafter only differences are discussed with respect to the first embodiment of the circuit 100A according as shown in Figure 2. Same features carry the same reference signs. In this example the secondary relay 2 is arranged in one or both of the positive and negative feed lines that connect the battery pack 101 and the engine 102. By interrupting the feed line the pre-charge relay PCR will lose power causing the main relay to disengage. While the secondary relay appears to be shown twice, much like the main relay this can be seen as a single relay, but acting on both lines.

Figure 7 shows a sixth embodiment of the circuit 100F according to the invention. Hereinafter only differences are discussed with respect to the fifth embodiment of the circuit 100E according as shown in Figure 6. Same features carry the same reference signs. The sixth embodiment differs in that the sensor is provided as an auxiliary contact AX, which is basically a switch that itself opens or closes a separate circuit from which the, opened or closed state of the main relay can be determined. This separate circuit is also powered by the external power source EP.

Figure 8 shows a seventh embodiment of the circuit 100G according to the invention. Hereinafter only differences are discussed with respect to the fifth embodiment of the circuit 100E according as shown in Figure 6. Same features carry the same reference signs. Instead the control means 3 is communicatively arranged to a pilot line PL, such as the proximity pilot or control pilot line. The pilot line terminates at the charging port (not shown, but customary). In this example a charge port plug P may be provided with a sender-receiver (not shown, but customary) and attached to the charging port. Such a plug would allow sensor information to be communicated to an external device. Additionally, the plug may comprise a communicator (not shown, but customary) for communicating instruction signals over the pilot line PL to the control means 3. The secondary circuit may in this example be controlled via the plug or external control means. Alternatively, the plug itself comprises a display, or LED lights for communicating sensor information, as well as a manual switch to allow a user to control the sending of electric instruction signals over the pilot line to the secondary relay. The external device, as well as the sender-receiver of the plug are therefore merely optional features in this embodiment. In a sense, the plug P itself may serve as an external device by which the secondary relay can be controlled. This is not unlike the examples according to Figures 4 and 5.

Figure 9 shows an eighth embodiment of the circuit 100G according to the invention. Hereinafter only differences are discussed with respect to the seventh embodiment of the circuit 100E according as shown in Figure 8. Same features carry the same reference signs. The second embodiment differs in that the sensor is provided as an auxiliary contact AX, which is basically a switch that itself opens or closes a separate circuit from which the, opened or closed state of the main relay can be determined. This separate circuit is also powered by the external power source EP.

It should be noted that wherever a plug P is shown the preceding figures a charging station CS, such as shown in Figure 1, can be provided instead. Additionally, wherever pilot line communications occur a superimposed signal may be used so as to not change information provided in the analogue electric signal over said pilot line, such as a proximity pilot signal or a control pilot signal. After all, such signals encode information analogously in the pulse-width train, amplitude and other features of the electric signal itself. As such, also separately from the above examples the superimposed signal is preferably be a digital signal that represents data as a sequence of discrete values, such as zero’s and one’s over the pilot signal which is an analogue signal.

Claims (17)

- 13 = CONCLUSIONS 1. A high-voltage direct current circuit (100) for supplying electrical energy from a high-voltage battery pack {101} to an electric motor (102), the circuit being provided with: - a main relay (1) for switching off the electrical current from the battery pack to the engine; - at least one charging relay; - a pre-charging relay; and - at least one auxiliary relay, characterized in that the circuit is further provided with: - a secondary relay (2) equipped with a control means (3) to allow external control of the relay and for reversible deactivation of the secondary relay (2), and wherein said secondary relay is assembled with the circuit (100) or the main relay (1) to actuate the main relay (1) to shut down the motor of the battery pack upon deactivation of the secondary relay, wherein the secondary relay is distinguished from the at least one charging relay, the pre-charging relay and the at least one auxiliary relay. The circuit of claim 1, wherein the secondary relay (2) is arranged to prevent the main relay from restoring electrical power to the motor when the secondary relay is in the deactivated state. The circuit according to claim 1 or 2, wherein the secondary relay comprises a transmitter-receiver (TP) for wireless communication and is arranged to be controlled remotely, such as via a wireless network (1). 4. The circuit according to any one of claims 1-3, wherein the secondary relay is arranged to be controlled via a CAN bus of the vehicle or via a pilot contact, such as a proximity pilot or control pilot contact. The circuit according to any one of claims 1 to 4, wherein a sensor (V, AX) is arranged to detect a state of the main circuit and is designed to be communicatively connected to the charging port for signaling the state of the main circuit. via a pilot contact, or communicatively connected to a transmitter-receiver for wireless transmission of the status of the main circuit. The circuit of claim 4 or 5, wherein the secondary relay includes a receiver for reversibly deactivating in response to a signal superimposed on a pilot signal, such as a proximity pilot or control pilot signal, and input through a charging port. The circuit according to any one of claims 1 to 6, wherein the secondary relay has an electrical power source, such as a low voltage power source (EP), external to the high voltage circuit, wherein reversing the deactivation of the secondary relay is powered by the electrical power source ( EP) which is outside the high-voltage circuit. 8. An electric vehicle consisting of: — a charging port; — a battery pack; - an electric motor; and - the circuit according to any of claims 1-7. A charging station for charging an electric vehicle according to claim 8 via the charging port, wherein the station includes a communication section for communicating with the secondary relay for deactivating the secondary relay. The station of claim 9, wherein the secondary relay comprises a transmitter-receiver for wireless communications and is arranged to be controlled remotely, and wherein the communication portion also comprises a transmitter-receiver, and wherein the communications portion communicates wirelessly with the secondary relay for deactivating it. The station according to claim 9 or 10, wherein the secondary relay is arranged to be controlled via a CAN bus of the vehicle, and wherein the transmitter-receiver of the secondary relay is connected to the CAN bus. The station according to any one of claims 9 to 11, wherein the secondary relay is controlled via a pilot contact, and wherein the secondary relay is a receiver - 15 = included to reversibly deactivate in response to an instruction signal superimposed on a pilot signal, and wherein the communications portion of the station is designed to superimpose the instruction signal over the pilot signal. 13. A charging port plug designed to shield the electrical contacts of the vehicle against charging, and comprising an electrical circuit that can be connected to a pilot contact of the charging port of the vehicle, and wherein the plug is designed to send an instruction signal to the vehicle via the pilot contact. The plug according to claim 13, characterized in that the electrical circuit is designed for superimposing the instruction signal on a pilot signal, such as a proximity pilot or control pilot signal. The plug according to claim 13 or 14, wherein the circuit comprises a wireless transmitter-receiver for transmitting the instruction signal to the vehicle and for receiving information from the vehicle. The plug of claim 14 or 15, further designed to be controllable via a wirelessly coupled device, such as a human interface, for transmitting the instruction signal, or including a manual switch for transmitting the instruction signal. 17. A pilot cable signal for an electric vehicle, consisting of: - a first signal being one of a proximity pilot signal and a control pilot signal; and — a second signal superimposed on the first signal.