Circuit arrangement for controlled pre-charging

Abstract

Vehicle system (10), comprising: a relay (54) and a coil (52) of a contactor, wherein the relay is configured to transfer current between a traction battery (14) and an electrical load (34) when it is closed; and a battery controller (16) configured to actuate a switch (66) so that the current flow from the traction battery (14) through the coil (52) and the switch (66), which bypasses the relay (54), causes the relay (54) to close in order to allow pre-charging of the load (34), characterized by the fact that the relay (54) and the coil (52) are connected in series and define a pre-charging contactor (46a) which is configured to open in response to the completion of pre-charging.

Description

TECHNICAL AREA

[0001] The present disclosure relates to systems and methods for arranging one or more components in a circuit for controlling the pre-charging of an electrical load. BACKGROUND

[0002] A hybrid or electric vehicle can be equipped with at least one traction battery configured to provide power for propulsion. The traction battery can also provide power to other electrical vehicle systems. For example, the traction battery can supply power to high-voltage loads such as compressors and electric heating elements. In another example, the traction battery can supply power to low-voltage loads such as a 12V auxiliary battery.

[0003] Publication JP 2009159804 A describes a vehicle system comprising a relay and a contactor coil, wherein the relay is configured to transfer current between a traction battery and an electrical load when closed. The vehicle system further includes a control unit configured to actuate a switch such that the current flow from the traction battery through the coil and the switch, bypassing the relay, causes the relay to close, allowing the load to be pre-charged. Further relevant prior art for the background of the invention is provided in Publication JP 2015225836 A. SUMMARY

[0004] A vehicle system includes a resistor connected to a relay and the coil of a contactor, the resistor being configured to limit the current flow through the contactor. The vehicle system also includes a traction battery, an electrical load, and a controller configured to actuate a switch, allowing current flow from the traction battery through the coil and resistor to close the relay and pre-charge the load.

[0005] A system for a vehicle includes a contactor defining a coil and a relay connected in series, the relay being configured to close in response to the current flowing through the coil exceeding a first threshold, a controller configured to allow current flow to the coil in response to a pre-charge request, and a resistor arranged with the contactor such that the current is below a second threshold greater than the first before the relay closes to pre-charge the load.

[0006] A method for a vehicle includes, in response to receiving a pre-charging request, by a controller, allowing current to flow to a pre-charging contactor, which includes a coil connected in series with a relay configured to close in response to the current through the coil exceeding a first threshold, and to a resistor arranged with the contactor such that the current through the coil is below a second threshold before the relay closes to pre-charge the load. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a block diagram of a hybrid electric vehicle (HEV) showing a typical powertrain and energy storage components; Fig. 2A is a schematic diagram representing an arrangement for pre-charging an electrical load; Fig. 2B is a schematic diagram representing a contactor; Fig. Figure 3 is a schematic diagram showing a circuit arrangement for controlled pre-charging using a pre-charging contactor coil as a pre-charging resistor; Fig. Figure 4 is a schematic diagram showing a circuit arrangement for controlled pre-charging using a main contactor coil to pre-charge the load; Fig. Figure 5 is a flowchart illustrating an algorithm for controlling the pre-charging of the load using a pre-charging contactor coil as a pre-charging resistor; and Fig. Figure 6 is a flowchart that illustrates an algorithm for controlling the pre-charging of the load using a main contactor coil. DETAILED DESCRIPTION

[0007] Here, embodiments of the present disclosure are described. It is understood that the disclosed embodiments are merely examples and that other embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be enlarged or reduced to show details of certain components. Accordingly, the specific structural and functional details disclosed here are not to be interpreted as limiting, but merely as a representative basis to teach those skilled in the art the diverse uses of the present invention.

[0008] Fig. Figure 1 depicts an exemplary hybrid electric vehicle (HEV) system 10. A hybrid electric vehicle 12, hereinafter referred to as vehicle 12, can comprise at least one traction battery 14. The traction battery 14 can include a battery controller 16 and be configured to receive an electrical charge via a charging process at a charging station connected to a power source. In one example, the power source can include a device that utilizes renewable energy, such as a photovoltaic (PV) solar panel or a wind turbine.

[0009] The traction battery 14 can comprise one or more accumulator cells (not shown), such as electromechanical cells, capacitors, or other types of energy storage devices. The accumulator cells can be arranged in any suitable configuration, including, but not limited to, in series or parallel, and they can be configured to absorb and store electrical energy for use in operating the vehicle 12. Each cell can provide the same or a different nominal voltage threshold. The accumulator cells can further be arranged in one or more series assemblies, sections, or modules, which can also be connected in series or parallel.

[0010] The traction battery 14 further comprises a Bused Electrical Center (BEC) 18, which is electrically connected to the battery cells, for example, via positive and negative battery terminals. The BEC 18 can include a variety of contactors and switches that enable the supply and withdrawal of electrical energy to and from the battery cells of the traction battery 14. For example, it can receive one or more commands, signals, or other notifications from the battery controller 16 indicating a request to actuate one or more of the variety of contactors and switches.

[0011] The battery controller 16 is electrically connected to the BEC 18 and controls the energy flow between the BEC 18 and the battery cells. For example, the battery controller 16 can be configured to monitor and manage the temperature and state of charge of each of the battery cells. In one example, the battery controller 16 can command the BEC 18 to actuate one or more of the multiple switches in response to the temperature or state of charge in a particular battery cell reaching a predefined threshold.In another example, the battery control unit 16 can be in a communication link with one or more vehicle control units 38, such as an engine control unit (ECM) and a transmission control unit (TCM), and it can command the BEC 18 to actuate one or more of the multitude of switches in response to a specified signal from the one or more vehicle control units 38.

[0012] The vehicle 12 may further comprise one or more electric machines 22 mechanically connected to a hybrid transmission 24. The electric machines 22 may be capable of operating as electric motors or generators. The hybrid transmission 24 may also be mechanically connected to a motor 26. The hybrid transmission 24 is also mechanically connected to a drive shaft 28, which is mechanically connected to the wheels 30.

[0013] The electric machines 22 can provide propulsion and braking capability using energy stored in the traction battery 14 when the motor 26 is switched on or off, for example via the BEC 18. The electric machines 22 also function as generators and can provide fuel consumption benefits by recovering energy that would normally be lost as heat in a friction braking system. The electric machines 22 can also provide reduced pollutant emissions, as the vehicle 12 can be operated in an electric mode under certain conditions.

[0014] The traction battery 14 typically provides a high-voltage DC output. The traction battery 14's BEC 18 can be electrically connected to an inverter system controller (ISC) 32. The ISC 32 is electrically connected to the electric machines 22 and provides the capability to transfer energy bidirectionally, such as via the BEC 18, between the traction battery 14 and the electric machines 22. In one example, the electric machines 22 and other vehicle components 12 that supply energy to and / or draw energy from the traction battery 14 can define a main load 34 of the traction battery 14.

[0015] In electric motor mode, the ISC 32 can convert the DC output provided by the traction battery 14 into three-phase alternating current (AC), as may be required for the proper functioning of the electric machines 22. In regeneration mode, the ISC 32 can convert the three-phase AC output from the electric machines 22, which function as generators, into a DC input requested by the traction battery 14. Fig. While Figure 1 depicts a typical hybrid electric vehicle, the present description is equally applicable to a purely electric vehicle. For a purely electric vehicle, e.g., a battery electric vehicle (BEV), the hybrid transmission 24 can be a gearbox connected to the electric machine 22, and the motor 26 may not be present. In one example, a main load 34 of the traction battery 14 in the BEV can include the electric machines 22 and the gearbox.

[0016] In addition to providing power for propulsion, the traction battery 14 can provide power to other electrical vehicle systems (generally shown as auxiliary loads 36). For example, the traction battery 14 can transfer power to high-voltage loads such as compressors and electric heating elements. In another example, the traction battery 14 can provide power to low-voltage loads such as a 12 V auxiliary battery. In such an example, the vehicle 12 may include a DC-DC converter module (not shown) that converts the high-voltage DC output of the traction battery 14 into a low-voltage DC supply compatible with the low-voltage loads. The various components described may include one or more associated controllers to control and monitor the operation of the components. The controllers may be connected via a serial bus (e.g.,a Controller Area Network (CAN) or communicate via discrete conductors.

[0017] At this point, we will refer to Fig. Reference is made to Figure 2A, which shows an exemplary arrangement 40 of the BEC 18 for energy transfer between the traction battery 14 and the main load (generally denoted by a capacitor symbol) 34. The arrangement 40 may include a pair of contactors 42a, 42b, such as a positive main contactor and a negative main contactor, electrically connected to corresponding terminals of the traction battery 14. In one example, closing the contactors 42a, 42b closes a circuit between the main load 34 and the traction battery 14, allowing the flow of electrical energy between the traction battery 14 and the main load 34. In another example, opening one or more of the contactors 42a, 42b opens the circuit between the main load 34 and the traction battery 14, interrupting the energy flow between them.In one example, the battery controller 16 can command the BEC 18 to open or close one or more of the contactors 42a, 42b in response to receiving a signal from one or more vehicle controllers 38, e.g. ECM, TCM and so on, indicating a request to initiate or stop the transfer of electrical energy between the main load 34 and the traction battery 14.

[0018] The arrangement 40 can further include a pre-charging circuit 44 configured to control a current-charging process at one of the terminals of the traction battery 14. The pre-charging circuit 44 can include a pre-charging contactor 46 connected in series with a pre-charging resistor 48. The pre-charging circuit 44 can be electrically connected in parallel with the contactor 42a, so that when the contactor 42a is open and the pre-charging contactor 46 and the contactor 42b are closed, electrical current can flow through the pre-charging circuit 44, providing controlled current-charging to the terminal of the main load 34 connected to the contactor 42a.

[0019] In one example, the battery controller 16 can be configured to initiate a pre-charging procedure using the pre-charging circuit 44 in response to receiving a signal indicating a request to close contactors 42a and 42b. The battery controller 16 can, for example, issue one or more commands to the BEC 18 to close contactor 42b and the pre-charging contactor 46, and to control the current flow to the terminal of the traction battery 14 connected to contactor 42a.

[0020] The battery controller 16 can also be configured to terminate the pre-charging procedure in response to the voltage across the open contactor, e.g., contactor 42a, exceeding a threshold value. The battery controller 16 can further be configured to command the BEC 18 to close contactor 42a in response to the voltage across the open contactor 42a falling below a threshold value.

[0021] As in Fig. As shown in Figure 2B, each of the contactors 42a, 42b and the pre-charging contactor 46 can define an electromechanical device 50 comprising an induction coil 52 and a relay 54. In one example, energizing the induction coil 52 using a predetermined amount of current, e.g., pull-in current I, causes Anzug , that relay 54 closes and inductive coil 52 is switched off; e.g., providing a current that is less than the drop current I causes AbfallThe effect is that relay 54 opens. In another example, the electromechanical device 50 can be configured, after relay 54 closes, to supply a predetermined amount of current, e.g., holding current I. Halt , to be passed through the inductive coil 52 in order to keep the relay 54 in a closed position.

[0022] In one example, the inrush current I Anzug stronger than the holding current I Halt and stronger than the waste stream I Abfall be. In such an example, the holding current I can be Halt stronger than waste stream I Abfall be. A value for the inrush current I Anzug can be, for example, 1.7 amperes (A), where a corresponding value for the holding current I Halt 0.4 A and a corresponding value for the waste stream I Abfall The value is 0.1 A. The values ​​for the inrush current I Anzug , the holding current I Halt and the waste stream I AbfallFor a given contactor, a function can be for one or more device characteristics, such as design and manufacturer specifications, manufacturing processes and materials, testing, age and / or cycle count of the contactor, and so on.

[0023] In relation to Fig. Figure 3 shows an exemplary arrangement 58 for controlling a pre-loading of the main load 34. As in relation to Fig. As described in Section 2A, the battery controller 16 can initiate a procedure to precharge the main load 34 in response to receiving a request to transfer energy between the traction battery 14 and the main load 34, or any other signal indicating a request to close contactors 42a and 42b. In response to the request, the battery controller 16 can issue a command to close contactor 42b. The battery controller 16 can be configured to precharge the main load 34 using one or more active and / or passive switching components, such as, but not limited to, a precharge contactor 46a, a diode 64, a switch 66, and a resistor 68.

[0024] The pre-charge contactor 46a can include a pre-charge contactor coil 60 and a pre-charge contactor relay 62, as for example in relation to the in Fig. Figure 2B describes the electromechanical device 50. In one example, the pre-charging contactor coil 60 and the pre-charging contactor relay 62 can be connected in series, for example via an external and / or internal coupling of one or more corresponding electrical lines. A series connection between the pre-charging contactor coil 60 and the pre-charging contactor relay 62 can enable controlled pre-charging of the main load 34.

[0025] Supplying power to the pre-charging contactor coil 60 can cause the pre-charging contactor coil 60 to draw current I Spule into one or more parts of the exemplary arrangement 58, e.g. due to an intrinsic resistance of the pre-charging contactor coil 60. The pre-charging contactor relay 62 can be configured to close, thereby initiating a pre-charging of the main load 34 in response to the current I Spulethrough the pre-charge contactor coil 60 above a threshold value. In one example, the pre-charge contactor relay 62 can be configured to close in response to the current I exceeding a threshold value. Spule , which flows through the pre-loading contactor coil 60, stronger than the inrush current I Anzug is.

[0026] The switch 66, when in a closed state, can electrically connect the pre-charge contactor 46a to the traction battery 14. This allows the pre-charge contactor 46a to be selectively powered using high-voltage (HV) power, for example, using a DC output from the traction battery 14. The battery controller 16 can be configured to selectively close the switch 66 to close the electrical circuit and supply power to the pre-charge contactor coil 60 of the pre-charge contactor 46a in response to a predefined signal or request. For example, the battery controller 16 can issue a command to close the switch 66 in response to receiving a signal indicating a request to close contactors 42a and 42b.The diode 64 can be configured to connect the main load 34 to the pre-charge contactor 46a, and it can be configured to prevent a reverse current flow into the traction battery 14.

[0027] In one example, the performance of the pre-charge contactor relay 62 can be affected in response to the fact that the current flowing through one or more parts of the exemplary arrangement 58, such as the pre-charge contactor coil 60, exceeds a threshold value, e.g., an upper limit current I. Obergrenze , where the upper limit current I Obergrenze stronger than the inrush current I Anzug The resistor 68 can be arranged with the pre-charging contactor coil 60 and the pre-charging contactor relay 62 of the pre-charging contactor 46a to reduce the current flow through one or more parts of the exemplary arrangement 58 so that it is below a threshold value, e.g. the upper limit current I. ObergrenzeThe resistor 68 can, for example, be arranged such that it reduces the current through the pre-charging contactor coil 60 so that it remains below the upper limit current I. Obergrenze In another example, the resistor 68 can be arranged with the pre-charging contactor coil 60 and the pre-charging contactor relay 62 of the pre-charging contactor 46a to keep the current flow through one or more parts of the exemplary arrangement 58 such that it is above a threshold value, e.g. the pull-in current I. Anzug The resistor 68 can, in one example, be arranged such that it maintains the current flow through the pre-charging contactor coil 60 such that it is above the pull-in current I. Anzug lies.

[0028] After the pre-charging contactor relay 62 closes, the exemplary arrangement 58 can initiate a first phase of pre-charging the main load 34, e.g., the first of a plurality of phases of a pre-charging process. The first phase of pre-charging the main load 34 can involve pre-charging the main load 34 to a predetermined threshold, such as a voltage higher than or equal to a voltage drop across the resistor 68. The battery controller 16 can be configured to determine whether the first phase of pre-charging the main load 34 has been completed. In one example, the battery controller 16 can determine whether the first phase of pre-charging the main load 34 has been completed based on the voltage across the open contactor 42a. The battery controller 16 can, in another example, respond to the voltage across the open contactor 42a being below a predetermined threshold, e.g.,B under a voltage drop across the resistor 68, determine that the first phase of precharging the main load 34 has been completed.

[0029] The battery controller 16 can further be configured to issue one or more commands to open the switch 66 in response to the determination that the first phase of precharging the main load 34 has been completed. Opening the switch 66 can increase the current flow through the precharging contactor relay 62, thus initiating a second phase of precharging the main load 34. The second phase of precharging the main load 34 can involve precharging the main load to a predetermined threshold, such as a voltage less than or equal to the voltage across the traction battery 14. As in the case of the first phase of precharging the main load 34, the battery controller 16 can also determine whether the second phase of precharging the main load 34 is complete, for example, based on the voltage across the open contactor 42a.The battery control 16 can issue one or more commands to close the contactor 42a in response to a determination that the second phase of precharging the main load 34 is complete, e.g. in response to a determination that the voltage across the open contactor 42a is below the voltage of the traction battery 14.

[0030] In relation to Fig. Figure 4 shows an exemplary arrangement 70 for controlling a pre-charging of the main load 34. When closed, the contactors 42c and 42b can be configured to connect the traction battery 14 and the main load 34, enabling the transfer of electrical power, e.g., via a current flow, between the two systems. The battery controller 16 can initiate a pre-charging of the main load 34 in response to receiving a request to transfer energy between the traction battery 14 and the main load 34, or any other signal indicating a request to close the contactors 42c and 42d. A diode 80 can be configured to connect the main load 34 to the contactor 42c and can also be configured to prevent reverse current flow into the traction battery 14.

[0031] When initiating the pre-charging of the main load 34, the battery controller 16 can issue a command to close a pre-charge switch 76 and initiate the current flow from the traction battery 14 to a contactor coil 74 of the contactor 42c via a pre-charge resistor 78. A contactor relay 72 of the contactor 42c can be configured to close, thereby initiating a pre-charging of the main load 34 in response to the current I Spule through the contactor coil 74 above a threshold value. In one example, the contactor relay 72 can be configured to close in response to the current I exceeding a threshold value. Spule , which flows through the contactor coil 74, stronger than the inrush current I Anzug is.

[0032] In one example, the performance of the contactor relay 72 may be impaired in response to the fact that current flowing through one or more parts of the exemplary arrangement 70, such as through the contactor coil 74, exceeds a threshold value, e.g., an upper limit current I. Obergrenze lies, whereby the upper limit current I Obergrenze stronger than the inrush current I Anzug The pre-charge resistor 78 can be arranged with the contactor coil 74 and the contactor relay 72 of the contactor 42c to reduce the current flow through one or more parts of the exemplary arrangement 70 so that it is below a threshold value, e.g. the upper limit current I. Obergrenze The pre-charge resistor 78 can, for example, be arranged such that it reduces the current through the contactor coil 74 so that it remains below the upper limit current I. ObergrenzeIn another example, the pre-charge resistor 78 can be arranged with the contactor coil 74 and the contactor relay 72 of the contactor 42c to keep the current flow through one or more parts of the exemplary arrangement 70 such that it is above a threshold value, e.g. the pull-in current I. Anzug The pre-charge resistor 78 can, in one example, be arranged such that it maintains the current flow through the contactor coil 74 such that it is above the pull-in current I. Anzug lies.

[0033] After the contactor relay 72 closes, the exemplary arrangement 70 can initiate a first phase of precharging the main load 34, e.g., the first of a plurality of phases of a precharging process. The first phase of precharging the main load 34 can involve precharging the main load 34 to a predetermined threshold, such as a voltage higher than or equal to a voltage drop across the precharging resistor 78. The battery controller 16 can be configured to determine whether the first phase of precharging the main load 34 has been completed. In one example, the battery controller 16 can determine whether the first phase of precharging the main load 34 has been completed based on the voltage across one or more of the contactors 42c, 42d. The battery controller 16 can, in another example, respond to the fact that the voltage across one or more of the contactors 42c, 42d falls below a predetermined threshold.B under a voltage drop across the pre-charge resistor 78, determine that the first phase of pre-charging the main load 34 has been completed.

[0034] The battery controller 16 can further be configured to issue one or more commands to open the pre-charge switch 76 in response to the determination that the first phase of pre-charging the main load 34 has been completed. Opening the pre-charge switch 76 can increase the current flow through the contactor relay 72, thus initiating a second phase of pre-charging the main load 34. The second phase of pre-charging the main load 34 can involve pre-charging the main load to a predetermined threshold, such as a voltage that is less than or equal to the voltage across the traction battery 14. As in the case of the first phase of pre-charging the main load 34, the battery controller 16 can also determine whether the second phase of pre-charging the main load 34 is complete, for example, based on the voltage across one or more contactors 42c, 42d.In response to the determination that the second phase of precharging the main load 34 has been completed, the battery controller 16 can issue one or more commands to actuate the precharging switch 76 at a predetermined duty cycle, e.g., so that the current flowing through the contactor coil 74 is greater than the holding current I. Halt The battery control unit 16 can also issue one or more commands to close the contactor 42d in response to a determination that the second phase of precharging the main load 34 is complete, e.g., in response to a determination that the voltage across the contactor 42d is below the voltage of the traction battery 14.

[0035] In relation to Fig. Figure 5 shows an exemplary process 82 for controlling a pre-charging of the main load 34. Process 82 can begin at block 84, where the battery controller 16 receives a signal indicating a request to close contactors 42a and 42b. In response to this request, the battery controller 16 can begin a process to pre-charge the main load 34. In one example, the battery controller 16 can issue a command at block 86 to close contactor 42b.

[0036] At block 88, the battery control unit 16 can issue a command to close the switch 66, thereby directing current to the pre-charging contactor coil 60 of the pre-charging contactor 46a and the resistor 68. The current I Spule , which flows through the pre-loading contactor coil 60 and is stronger than the inrush current I AnzugThis can cause the pre-charging contactor relay 62 to close, thus initiating pre-charging of the main load 34. The resistor 68 arranged with the pre-charging contactor coil 60 and the pre-charging contactor relay 62 of the pre-charging contactor 46a can reduce the current through the pre-charging contactor coil 60 so that it remains below the upper limit current I. Obergrenze lies, and can furthermore the current I Spule , which flows through the pre-loading contactor coil 60, so that it is stronger than the inrush current I Anzug is, where the upper limit current I Obergrenze stronger than the inrush current I Anzug is.

[0037] After the pre-charge relay 62 closes, initiating the first phase of pre-charging the main load 34, the battery controller 16 can be configured to determine at block 90 whether the first phase of pre-charging the main load 34 has been completed, for example, based on the voltage across the open contactor 42a. In one example, the battery controller 16 can measure the voltage across the open contactor 42a for a predetermined period and / or a predetermined number of times before determining whether pre-charging the main load 34 has been completed. At block 92, the battery controller 16 can then issue a diagnostic message indicating that block 90 has determined that the first phase of pre-charging the main load 34 has not been completed, for example, that the voltage across the open contactor 42a remains above a voltage drop across resistor 68 after a predetermined period.

[0038] In response to the determination at block 90 that the first phase of precharging the main load 34 has been completed, the battery controller 16 at block 94 can issue a command to open switch 66, initiating a second phase of precharging the main load 34. At block 96, the battery controller 16 can be configured to determine whether the second phase of precharging the main load 34 has been completed, for example, based on the voltage across the open contactor 42a after a predetermined period. At block 92, the battery controller 16 can issue a diagnostic message indicating that block 96 has determined that the second phase of precharging the main load 34 has not been completed, for example, that the voltage across the open contactor 42a is higher than the voltage of the traction battery 14 after a predetermined period.

[0039] In response to the determination at block 96 that the second phase of precharging the main load 34 has been completed, the battery controller 16 at block 98 can issue one or more commands to close contactor 42a. In one example, the battery controller 16 can determine that precharging of the main load 34 has been completed in response to the voltage across the open contactor 42a falling below a predefined threshold. Subsequently, process 82 can terminate. In some examples, process 82 can be repeated in response to receiving a signal indicating a request to close contactors 42a and 42b, or in response to another signal or request.

[0040] In relation to Fig.Figure 6 shows an exemplary process 100 for controlling a pre-charging of the main load 34. Process 100 can begin at block 102, where the battery controller 16 receives a signal indicating a request to close contactors 42c and 42d. In response to the request, the battery controller 16 can begin a process to pre-charge the main load 34. In one example, the battery controller 16 can issue a command at block 104 to close the pre-charge switch 76, thereby supplying power to the contactor coil 74 of contactor 42c and the pre-charge resistor 78. In another example, supplying power to the contactor coil 74 and the pre-charge resistor 78 can cause the contactor coil 74 to conduct current I. Spule leads to the current I Spule , which flows through the pre-loading contactor coil 60, and is stronger than the inrush current I AnzugThis can cause the contactor relay 72 to close, thus initiating a pre-charging of the main load 34. The pre-charging resistor 78, arranged with the contactor coil 74, and the contactor relay 72 of the pre-charging contactor 42c can reduce the current through the contactor coil 74 so that it remains below the upper limit current I. Obergrenze lies, and can furthermore the current I Spule , which flows through the contactor coil 74, so that it is stronger than the inrush current I Anzug is, where the upper limit current I Obergrenze stronger than the inrush current I Anzug is.

[0041] After the contactor relay 72 closes, initiating the first phase of precharging the main load 34, the battery controller 16 can be configured to determine at block 106 whether the first phase of precharging the main load 34 has been completed, for example, based on the voltage across contactor 42d. In one example, the battery controller 16 can measure the voltage across contactor 42d for a predetermined period and / or a predetermined number of times before determining whether precharging the main load 34 has been completed. At block 108, the battery controller 16 can then issue a diagnostic message indicating that block 106 has determined that the first phase of precharging the main load 34 has not been completed, for example, that the voltage across the open contactor 42d remains above a voltage drop across the precharging resistor 78 after a predetermined period.

[0042] In response to the determination at block 106 that the first phase of precharging the main load 34 has been completed, e.g., that the voltage across the open contactor 42d is below a voltage drop across the precharging resistor 78, the battery controller 16 at block 110 can issue a command to open the precharging switch 76, initiating a second phase of precharging the main load 34. At block 112, the battery controller 16 can be configured to determine whether the second phase of precharging the main load 34 has been completed, for example, based on the voltage across contactor 42d after a predetermined period. At block 108, the battery controller 16 can issue a diagnostic message in response to the determination at block 112 that the second phase of precharging the main load 34 has not been completed, e.g.,, that the voltage across contactor 42d is higher than the voltage of traction battery 14 after a specified period of time.

[0043] In response to the determination at block 112 that the second phase of precharging the main load 34 has been completed, e.g., that the voltage across contactor 42d is below the voltage of the traction battery 14, the battery control 16 at block 114 can issue one or more commands to actuate the precharging switch 76 so that the current flowing through the contactor coil 74 is greater than the holding current I Halt The battery controller 16 can also issue a command to close contactor 42d. Process 100 can then end. In some examples, process 100 can be repeated in response to receiving a signal indicating a request to close contactors 42c and 42d, or in response to another signal or request.

[0044] The processes, methods, or algorithms disclosed herein can be implemented by a processing device, controller, or computer, which may contain an existing programmable electronic control unit or a dedicated electronic control unit. Likewise, the processes, methods, or algorithms can be stored as data and instructions that can be executed by a controller or computer in many forms, including, but not limited to, information permanently stored on non-writable storage media such as ROM devices, and information modifiably stored on writable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media. The processes, methods, and algorithms can also be implemented in a software-executable object.Alternatively, the procedures, methods or algorithms can be implemented wholly or partially using suitable hardware components, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software and firmware components.

Claims

[1] Vehicle system (10), comprising: a relay (54) and a coil (52) of a contactor, wherein the relay is configured to transfer current between a traction battery (14) and an electrical load (34) when it is closed; and a battery controller (16) configured to actuate a switch (66) so that the current flow from the traction battery (14) through the coil (52) and the switch (66), which bypasses the relay (54), causes the relay (54) to close in order to allow pre-charging of the load (34), characterized by , that the relay (54) and the coil (52) are connected in series and define a pre-charging contactor (46a) which is configured to open in response to the completion of pre-charging. [2] Vehicle system (10) according to claim 1, wherein the battery control (16) is further configured to actuate the switch (66) such that causing the relay (54) to close allows a pre-charging of the load (34) to a first threshold value, and then actuates the switch (66) to allow a pre-charging of the load (34) to a second threshold value. [3] Vehicle system (10) according to claim 2, wherein the second threshold is above the first threshold. [4] Vehicle system (10) according to claim 2, wherein the first threshold corresponds to a voltage measured across a relay bypass path and wherein the second threshold corresponds to a voltage measured across the traction battery (14). [5] Vehicle system (10) according to claim 4, wherein the pre-charging of the load (34) to a voltage measured across the traction battery (14) indicates completion of the pre-charging. [6] Vehicle system (10) according to claim 1, further comprising a resistor (68) connected to the relay (54) and the coil (52) such that an amount of current bypassing the relay (54) is greater than a pull-in current that causes the relay (54) to close and less than an upper limit current that causes the temperature of the coil (52) to exceed a predetermined value. [7] Method for a traction battery (14), comprising: in response to receiving a pre-charge request, by a battery controller (16), selectively allowing current from the traction battery (14) to flow through a coil (52) of a contactor and bypass a relay (54) of the contactor before the relay (54) closes, in order to allow pre-charging of a load (34) to a first threshold voltage, characterized by , that The method further comprises, in response to the pre-charging of the load (34) to the first threshold voltage, selectively allowing current from the traction battery (14) to flow through the coil (52) and the relay (54) to permit pre-charging of the load (34) to a second threshold voltage which is higher than the first. [8] Method according to claim 7, wherein the first threshold voltage corresponds to a voltage across a relay bypass path and the second threshold voltage corresponds to a voltage across the traction battery (14). [9] Method according to claim 8, wherein the precharging of the load (34) to a voltage across the traction battery (14) indicates completion of the precharging. [10] Method according to claim 7, wherein the contactor is a preloading contactor (46a) configured to open in response to the completion of the preloading.

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