Plug-in charging for electric vehicles and towed electric trailers

Abstract

A tow vehicle and the trailer include respective batteries and an electric powertrain for propulsion. A connector system connects the vehicle and the trailer via a plurality of conductors, a plug and a receptacle including at least seven connector pins. Due to the wire gauge, each conductor carries no more than 20 amperes. When a drive condition is detected, a first switch matrix in the vehicle and a second switch matrix in the trailer enter a first configuration to connect a plurality of light sources in the trailer to a lighting signal generator in the tow vehicle. When a charge condition is detected, a second configuration of the switch matrices is entered to carry a charging current that is split in parallel among a plurality of conductors in the connector system and then recombined to provide a charging current in excess of 20 amperes.

Description

FIELD OF TECHNOLOGY

[0001] The present invention relates generally to electrified trailers to be towed by electrified passenger vehicles, and more particularly to an electrical coupling between such trailers and vehicles. BACKGROUND OF THE INVENTION

[0002] The battery capacity conventionally available in electrified vehicles (EVs) has created challenges in providing sufficiently long driving distances (i.e., driving range) before they require recharging. In addition to providing adequate driving range, it is desirable to keep the time required to reach a desired state of charge as short as possible when charging an electric vehicle.

[0003] Improvements in electrified vehicles have allowed them to be used in many types of vehicle usage applications, including towing trailers for expanded cargo capacity or camping. The associated weight increase means the electric traction motor has to work harder to pull the trailer, resulting in higher power consumption and greater battery drain (and consequently, longer downtime while plugged into a charger to refill the battery pack). On average, towing a trailer can reduce an EV's driving range by about 50%.

[0004] To help mitigate the loss of driving range, a trailer itself can be electrified. For example, an electrified trailer (ET) may carry a battery or battery pack along with a driving system (e.g., a propulsion system) that includes an electric traction motor that is engaged while driving to power the ET and reduce the load requirements for the EV. The high-capacity battery and electric traction motor in the trailer can also be used to reduce the load caused by towing a caravan for an internal combustion engine (ICE) vehicle.

[0005] When an EV is operated in conjunction with an ET, there is a need to charge the two respective battery systems. Whether public or private, most charging stations are designed to accommodate a single vehicle rather than a train arrangement. Using a single charger to charge the vehicle and trailer separately may require an undesirably long cable to plug into one for an initial period and then swap the cable to the other for a second period without moving the vehicle and trailer combination. Otherwise, a driver may be required to perform difficult maneuvers to park and repark the vehicle and coupled trailer in different positions for charging cable access to the vehicle and trailer one after the other.

[0006] Some trailers have been proposed whose primary purpose is to carry an auxiliary battery connected to the battery system of the main electrified vehicle to extend driving range. In this case, cables designed to carry high voltage and current levels are used between the auxiliary battery and the main vehicle. If high-capacity wiring is present, charging can be simplified, as charging current can be shared from one of the vehicle or trailer (which is connected to a charger) to the other (which is not connected to a charger). However, such a charging scenario requires not only high-capacity wiring but also the appropriate functional components and programming that enable such charging current sharing.Therefore, the problem remains for EVs that are not specifically designed to share high power levels with a trailer.

[0007] EVs, such as electrified trucks, SUVs, and motorhomes, may typically include conventional trailer wiring for powering signaling lights (such as brake lights, turn signals, and auxiliary lights), controlling auxiliary braking systems in a trailer from the main braking system, or providing a communications bus (e.g., CAN bus) to connect the trailer electronics to the tow vehicle. As used herein, a signaling-based trailer connector refers to a vehicle-trailer interface (as defined in standards, including SAE J2863, SAE J560, ISO 1724, and ISO 11446) configured for use with voltages no higher than 24 V. Common examples of the connectors include Pollak male and female connectors and Bargmann connectors.The wiring sizes used with signal-based trailer connectors typically range from 16 AWG to 12 AWG, which is much smaller than the wire sizes used to split the battery charge to provide traction or charge a battery. For example, individual conductors in typical signal-based trailer connectors may be limited to approximately 20 amps, while Level 2 charging of electrified vehicles (the most commonly installed type of EV battery charger) supports currents up to 80 amps. SUMMARY OF THE INVENTION

[0008] In one aspect of the invention, an apparatus for connecting a towing vehicle and a trailer is provided. The towing vehicle and the trailer each include a respective battery and a respective electric powertrain for propulsion during a driving condition. The apparatus includes a first switch matrix in the towing vehicle and a second switch matrix in the trailer. A connector system includes a plurality of conductors, a plug, and a receptacle, with at least seven connector pins in the plug and receptacle interconnecting the first and second switch matrices via the plurality of conductors. A controller is configured to induce a first connection state within the first and second switch matrices during the driving condition such that illumination signals from the towing vehicle are coupled to signaling lights on the trailer via the connector system.The controller is configured to cause a second connection state within the first and second switch matrices when the towing vehicle and the trailer are not in the drive state, such that a current suitable for charging one of the respective batteries is carried in parallel across at least two of the plurality of conductors. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic view of an electrified vehicle pulling a series arrangement of two trailers carrying secondary battery units. Fig. Figure 2 is a schematic view of an electrified trailer coupled to an electrified vehicle through a small gauge trailer lighting connector. Fig. Figure 3 is a plan view of a charging station layout that includes drive-through lanes to accommodate longer vehicles. Fig. Figure 4 is a schematic view of a trailer plug and socket wiring diagram connecting circuits of an electrified trailer and an electrified vehicle. Fig. Figure 5 is a wiring diagram showing individual wire reassignment during a charging mode. Fig. Figure 6 is a block diagram showing an electrified trailer and an electrified vehicle in more detail. Fig. Figure 7 is a flow diagram showing a preferred method of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0009] Fig. 1 shows an electrified vehicle 10 (which may be a battery-electric vehicle, or BEV, or a gasoline-powered hybrid vehicle) configured as an electric pickup truck. The vehicle 10 includes an onboard rechargeable battery unit 11 that stores electrical power for a traction motor (not shown) to propel the vehicle 10. The traction motor may include an electric machine mechanically coupled to a transmission, which may include a differential. The electric machine may also act as a generator during deceleration to recover energy that would normally be lost as heat in a friction braking system.

[0010] The battery pack 11 may consist of multiple cells to provide a high-voltage direct current (DC) output. A contactor module may selectably connect the battery pack 11 to a high-voltage bus (not shown). A power electronics module (not shown) controls the operation of the electric machine and provides the ability to transfer power bidirectionally between the battery pack 11 and the electric machine. The power electronics module may convert the DC voltage into a three-phase AC current to operate the electric machine. In a regeneration mode, the power electronics module may convert the three-phase AC current from the electric machine, which acts as a generator, into the DC voltage to charge the battery pack 11.

[0011] The vehicle 10 is configured to charge the battery unit 11 from external power sources (e.g., battery chargers) using one or more charging ports 12 and 13. External power sources may include electrical outlets at private or public locations. An electric vehicle supply equipment (EVSE) for connecting to a vehicle's charging port may include a charging unit at a charging station (e.g., a location having parking spaces or bays, each equipped with one or more charging units).A charging station serving a plurality of electrified cars and trucks may be connected to an electric power distribution network or power grid, as provided by an electric utility, and may be managed by electronic control systems that allow users to reserve a time period and a charging outlet for their use, as described in patent application publication US 2020 / 0148068A1 and in patent specification US 11,001,161, both of which are incorporated herein by reference.

[0012] The trailer 14 is an electrified trailer that includes a battery pack 15 and an electric machine (not shown) for independently powering the trailer 14 to synchronize with the forward or reverse propulsion of the vehicle 10, such that the presence of the trailer 14 does not prematurely deplete a state of charge (SOC) of the battery pack 11 in the vehicle 10. The trailer 14 may include one or more charging ports 17 and 18 configured to deliver charging currents from an external battery charger to charge the battery pack 15. A trailer hitch system 16 couples the vehicle 10 and the trailer 14 in a towing arrangement that includes mechanical linkage and electrical connections.In particular, the trailer coupling system 16 may be of a type intended to provide electrical coupling for conventional trailer functions, to operate trailer signal lighting (e.g., brake lights, turn signals, or position lights), to transmit control signals to trailer-mounted brakes, to couple additional low-current DC voltage for other trailer accessories, or to transmit electronic bus communication signals. Furthermore, the trailer coupling system 16 may lack any wiring or other components to support the transfer of battery charging currents between the vehicle 10 and the trailer 14. Thus, the battery unit 11 may be charged only using the charging ports 12 and 13 located on the vehicle 10, and the battery unit 15 may be charged only using the charging ports 17 and 18 located on the trailer 14.

[0013] Fig. 2 shows the vehicle 10 and the trailer 14 in more detail. A connector system 21 electrically couples the tow vehicle 10 and the electrified trailer 14. A signaling-based trailer connector includes a plug 22 carried by the trailer 14 and a receptacle 23 mounted on the vehicle 10. A plurality of pin assemblies 24 and a plurality of conductors 25 convey electrical signals and have a configuration (e.g., wire size and material) that supports lighting and communication signals with currents up to approximately 20 amperes. A branch 26 routes electrical signals via other trailer wiring to a plurality of light sources 20A-20D and a trailer brake unit 27. On the vehicle side, a wiring harness H connects the receptacle 23 to a control module 19 and other vehicle electronics, as is known in the art.The control module 19 can generate the required voltage / current from the powered light sources 20A-20D, or a separate driver can be used. In embodiments of the invention described below, a power manager / voltage controller can be further connected to the wiring harness H and the battery charging receptacle 23.

[0014] In Fig. 2, the trailer 14 is of a known type, incorporating self-propulsion, with power from a battery 15 being applied to electrical loads 28. The loads 28 may include a traction motor, an inverter, and a motor controller for driving the trailer 14 to follow the movement of the vehicle 10. A power manager 29 is coupled between the charging port 17 and the battery unit 15 to perform conventional charging when connected to an external battery charger.

[0015] Fig. 3 shows a drive-through layout of a charging station 30 having charging outlets 31-33 positioned adjacent to a plurality of drive-through lanes 34-37. In a charging station with such a layout, the vehicle 10 and trailer 14 combination can be parked such that the towing vehicle 10 and trailer 14 can be charged simultaneously, for example, by connecting them to separate chargers 31 and 32. However, such a drive-through arrangement may be rare for public stations. In addition, the availability of multiple chargers and the charger placement (or the length of the power cables) to reach both a vehicle and a trailer simultaneously may be very unlikely for residential installations.It would be desirable to charge both a tow vehicle and an electrified trailer while remaining at a single parking location and using only a single charger / cable pull into a single charging port of the vehicle and trailer combination.

[0016] Fig. Figure 4 is a schematic view of an embodiment of the present invention wherein a standard signaling-based trailer connector includes a plug 40 and a socket 41. In a typical 7-wire arrangement, the pins and wiring conductors associated with the plug 40 and the socket 41 define a plurality of conductive traces 42 including a ground wire 43, a brake control wire 44, a tail light wire 45, an auxiliary power wire 46, a left turn / brake light wire 47, a right turn / brake light wire 48, and a backup light wire 49. A switch matrix 50 in the vehicle and a switch matrix 51 in the trailer are connected to the socket 41 and the reverse light wire 49, respectively.connected to the connector 40 to utilize the conductive traces 42 according to two purposes: (1) normal driving operation during a driving condition, and (2) providing multiple parallel current paths for distributing a charging current into smaller current portions to enable the transfer of a total charging current greater than the individual rating of any of the conductive traces in the trailer connector. The matrix 50 and the matrix 51 may preferably consist of, for example, electronically controlled relay switches. In a first connection state of the matrices 50 and 51, which is selected in the driving condition, individual switches in the matrices connect lighting signals from a control system 52 in the towing vehicle to conventional trailer wiring leading to signaling lights on the trailer.In a second connection state of the matrices 50 and 51, which is caused during a battery charge state, the individual relay switches connect the conductive traces 42 to a power and battery system 53 in the vehicle and a power and battery system 54 in the trailer, so that a current suitable for charging one of the respective batteries is carried in parallel over at least two of the plurality of conductive wires 43-49.

[0017] Fig. Figure 5 shows an example of reassigning conductor wires according to pairs of wires to each carry a respective portion of current through the interconnect system, which can then be recombined in the power / battery system of the receiving one of the vehicle or trailer. Depending on the relative sizes of the actual available wire gauges, one or more wires may be provided to carry a positive side of a respective portion of the current, while one or more wires may be provided to carry the ground side of that respective portion of the current. Fig. Figure 5 shows a one-to-one correspondence of wires in each current portion. Thus, wires 43 and 44 carry a first current portion C1, wires 45 and 46 carry a second current portion C2, and wires 47 and 48 carry a third current portion C3. For example, if each of the current portions C1, C2, and C3 were limited to 20 amps each by wire gauge sizes, the current portions can be recombined at a receiving end to provide a battery charging current of up to 60 amps.

[0018] Fig. Figure 6 shows an embodiment of the invention with an EV on one side of the electrified vehicle and an ET on one side of the electrified trailer. Connectors 40 and 41 of a connector system interconnect the vehicle and trailer between switch matrices 50 and 51. Matrices 50 and 51 are shown as relays coupling a plurality of conductors through the respective connectors to carry either a set of drive signals (during a drive state) or a set of charge signals (during a battery charge state). On the EV side, relay 50 is connected to a power manager / voltage controller 60, which interfaces with a battery pack 11 and a charge port 12. A controller 25 is connected to the power manager / voltage controller 60 and to the charge port 12 to operate charging functions in a known manner.The controller 25 is coupled to the relay 50 to select between configurations of individual switches in the relay 50 to couple the connector 41 either to sources of light signaling / trailer braking signals during the drive condition or to battery charging signals (either to or from the vehicle) during a charging condition. The controller 25 is further connected to a memory 61 having a specification database for identifying wire gauge sizes according to an identification or classification of a particular trailer that is present. Identification may be made according to identification signals sent from the trailer to the controller 25 via the connector system or according to other means of identification (e.g., capturing an image of the trailer for analysis or through manual input from a vehicle user). A human-machine interface (HMI) 62 is provided for manual input.Alternatively, user inputs may be obtained via a wireless connection through a wireless transceiver 63 to communicate with a mobile device carried by the user. The MMS 62 and / or a mobile application on the mobile device may further provide an interface for specifying charging parameters for distributing charging currents in the charging mode, as described below.

[0019] Controller 25 is coupled to relay 50 for selecting between a first and a second switch configuration, as well as for supplying vehicle lighting signals during the drive state. Controller 25 interfaces with power manager / voltage controller 60 to appropriately configure corresponding portions of a charging current during the charging state and distribute the current portions to respective inputs of relay 50 so that the current portions are coupled in parallel to different conductors of the connector system. The parallel currents can then be recombined in the trailer after being routed via relay 51 to a power manager / controller 66 in the trailer.

[0020] The trailer further includes a controller 64 for controlling the operation of the power manager / voltage controller 66 and for selecting between the first and second configurations of the relay 51 (i.e., to route signals between the connector system and either the light source and auxiliary brake units 65 or the power manager / voltage controller 66). The trailer-side charging port 17 is similarly coupled to the controller 64 and the power manager / voltage controller 66, with the controller 64 capable of sensing a charge state on the trailer side and initiating the transmission of charging signals to the vehicle via the connector system. Fig.Figure 7 shows a preferred method of the invention wherein a check is performed in step 70 to determine if the vehicle / trailer is in a drive mode. The drive mode may be initiated when a vehicle's power transmission is engaged, when a vehicle is in gear, or in response to any other vehicle status other than vehicle charging. If the drive mode is detected, the relays are set for trailer driving in step 71. The configuration of the relays connects a light signal generator in the vehicle to light sources in the trailer (i.e., each of the conductors in the connector system functions according to its standard trailer signaling and / or braking functions). If no drive mode is detected, a check is performed in step 72 to determine if the vehicle / trailer is in a charging mode.For example, the charging mode can be detected when a charging port becomes active. If no charging mode is detected, the system returns to step 70 for further monitoring.

[0021] If a charging port is active in step 72, a determination is made in step 73 of any charge sharing requirement between the vehicle and trailer battery units (e.g., whether one or both batteries need to be charged). Preferably, a user may be provided with an opportunity to determine various charging parameters, such as specifying a charging order (either the vehicle or the trailer first) or specifying target charge levels for at least one of the battery units. The user may choose to charge both batteries simultaneously. A user may instead specify initially charging one of the battery units to an initial target level, subsequently charging the other battery unit to a different target level, and then returning to charging the first battery unit to yet another target level (e.g., fully charged).

[0022] Based on the selected charge distribution and the corresponding wire gauge sizes present in the connector system, current shares are allocated to the corresponding wires of the connector system in step 74. In step 75, the power managers and relays are configured according to the current allocations from step 74. After configuring the relays and power managers, a charging current is obtained from the charging port and distributed according to the allocations. The current flow and charging levels are monitored in step 76, and the current flows are adjusted as needed when various target levels are reached. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2020 / 0148068A1

[0011] US 11,001,161

[0011]

Claims

[1] A device connecting a towing vehicle and a trailer, the towing vehicle and the trailer each including a respective battery and a respective electric drive train for propulsion during a driving condition, the device comprising: a first switch matrix in the towing vehicle; a second switch matrix in the trailer; and a connector system comprising a plurality of conductors, a plug, and a socket, wherein at least seven connector pins in the plug and the socket interconnect the first and second switch matrices via the plurality of conductors; and a controller configured to induce a first connection state within the first and second switch matrixes while the vehicle is stationary, such that lighting signals from the towing vehicle are coupled to signaling lights on the trailer via the connector system, and configured to induce a second connection state within the first and second switch matrixes when the towing vehicle and the trailer are not in the running state, such that a current suitable for charging one of the respective batteries is carried in parallel across at least two of the plurality of conductors. [2] The device of claim 1, further comprising a current regulator configured to direct a plurality of parallel currents to respective ones of the plurality of conductors, each respective parallel current being limited within a respective predetermined maximum current capacity of each respective conductor according to its respective wire gauge. [3] The device of claim 2, wherein the controller is configured to (1) determine an identification of at least one of the towing vehicle or the trailer and (2) obtain the respective predetermined maximum current capacities of the corresponding conductors in a specification database according to the identification. [4] The device of claim 1, wherein at least one of the towing vehicle and the trailer has a charging port adapted to be connected to an external battery charger, and wherein in response to the charging port being coupled to the external battery charger, it is detected that a non-driving condition exists. [5] The device of claim 1, wherein the battery receiving the current suitable for charging is located in one of the towing vehicle or the trailer, and wherein the other of the towing vehicle or the trailer includes a charging port suitable for connection to an external charger to generate the current suitable for charging. [6] The device of claim 1, wherein the controller is responsive to a selection made by a user to determine a load distribution between the towing vehicle and the trailer. [7] The device of claim 6, wherein the predetermined charge distribution includes a charging order or a target charge level for at least one of the respective batteries in the towing vehicle and the trailer. [8] A method of interconnecting a towing vehicle and a trailer, the towing vehicle and the trailer each including a respective battery and a respective electric drive train for propulsion, the towing vehicle and the trailer being electrically connected via a connector system comprising a plurality of conductors, a plug and a socket, the plug and the socket including at least seven connector pins, the connector pins and the respective conductors being configured to carry no more than 20 amperes, the method comprising the following steps: Recording the driving status of the towing vehicle and the trailer; in the driving state, configuring a first switch matrix in the towing vehicle and a second switch matrix in the trailer in a first configuration for connecting the connector system between a plurality of light sources in the trailer to a lighting signal generator in the towing vehicle; Recording the load status of the towing vehicle or trailer; and in the charging state, configuring the first switch matrix in the towing vehicle and the second switch matrix in the trailer in a second configuration to carry a current suitable for charging one of the respective batteries in parallel across at least two of the plurality of conductors in the connector system. [9] The method of claim 8, further comprising the step of directing a plurality of respective parallel currents to respective conductors, each respective parallel current being limited to a respective predetermined maximum current capacity of each respective conductor according to its respective wire gauge. [10] The method of claim 9, further comprising the following steps: Determining an identification of at least one of the towing vehicle or the trailer; and Obtaining the respective predetermined maximum current capacities of the respective conductors from a specification database according to the identification. [11] The method of claim 8, wherein at least one of the towing vehicle and the trailer has a charging port adapted to be connected to an external battery charger, and wherein the state of charge is detected in response to the charging port being coupled to the external battery charger. [12] The method of claim 8, wherein the battery receiving the current suitable for charging is located in one of the towing vehicle or the trailer, and wherein the other of the towing vehicle or the trailer includes a charging port suitable for connection to an external charger to generate the current suitable for charging. [13] The method of claim 8, further comprising the step of a user specifying a load distribution between the towing vehicle and the trailer. [14] The method of claim 13, wherein the determined charge distribution includes an order of charging or a target charge level for at least one of the respective batteries in the towing vehicle and the trailer.

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