Control method of vehicle-mounted power battery, battery management system and vehicle

Abstract

The invention provides a control method of a vehicle-mounted power battery, a battery management system and a vehicle, and solves the technical problem of potential safety hazards caused by relay adhesion in the prior art. According to the control method of the vehicle-mounted power battery, in the high-voltage power-on process, the capacitor is pre-charged firstly, when the voltage at the two ends of the capacitor is close to the rated voltage of the power battery, the main loop is switched to supply power to the load, at the moment, the impact current passing through the main negative relay is very small, and the load is not damaged. The main negative relay is completely within the bearing range of the main negative relay, and the relay is not damaged, so that the main negative relay in a main loop is protected, and the probability of potential safety hazards caused by adhesion of the main negative relay is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and particularly to a control method for in-vehicle power batteries, a battery management system, and a vehicle. Background Art

[0002] Existing new energy vehicles generally have a high-voltage circuit in the power battery. There are relays for the power battery in the high-voltage main circuit. The relays for the power battery include a main positive relay and a main negative relay, which realize the high-voltage power supply of the power battery to the motor and other loads.

[0003] As a core component of the power battery system, the relay plays an important role in the realization of the functions of the power battery system. During the use of the power battery system, the relay will frequently perform closing and opening actions based on the control strategy. However, the suction and disconnection of the relay have a service life limit. As the number of suction and disconnection times of the relay continues to accumulate, it may cause the relay to stick, resulting in difficulty in correctly disconnecting the high-voltage main circuit, thus triggering safety hazards such as battery overheating, short circuit, and even fire. Summary of the Invention

[0004] In view of this, the present application provides a control method for in-vehicle power batteries, a battery management system, and a vehicle. The impact current of the main negative relay is very small, completely within the tolerance range of the main negative relay, and will not cause damage to the relay. Therefore, it plays a protective role for the main negative relay in the main circuit and reduces the probability of safety hazards caused by the adhesion of the main negative relay.

[0005] To achieve the above object, the present application provides the following technical solutions: The present application provides a control method for in-vehicle power batteries. The control method is applicable to a battery management system. The battery management system includes a control circuit. Among them, the control circuit includes a power battery, an air-conditioning control circuit, and a high-voltage control circuit. The high-voltage control circuit includes a pre-charge circuit and a main circuit parallel to the pre-charge circuit, a capacitor, and a load parallel to the capacitor. Through the pre-charge circuit and the main circuit, the power battery charges the capacitor to supply power to the load;

[0006] Among them, the control method includes:

[0007] When receiving a high-voltage command sent by the vehicle controller, generate a pre-charge command and a first disconnection command. The pre-charge command is used to control the pre-charge circuit to conduct and continuously conduct for a first preset duration, so that the power battery pre-charges the capacitor for the first preset duration. The first disconnection command is used to control the main circuit to disconnect;

[0008] When the power battery pre-charges the capacitor for the first preset duration, a main charging instruction is generated. The main charging instruction is used to control the conduction of the main circuit, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit, so that the voltage across the load is a first preset voltage, and the difference between the rated voltage of the power battery and the first preset voltage is less than a preset threshold;

[0009] When the difference between the rated voltage of the power battery and the first preset voltage is less than a preset threshold, a second disconnection instruction is generated. The second disconnection instruction is used to control the disconnection of the pre-charge circuit.

[0010] In an embodiment of the present application, the pre-charge circuit includes a pre-charge relay and a pre-charge resistor connected in series with the pre-charge relay;

[0011] Wherein, the first preset duration is calculated according to the capacitance value of the capacitor, the resistance value of the pre-charge resistor and a preset constant.

[0012] In an embodiment of the present application, the preset constant is 3 to 5.

[0013] In an embodiment of the present application, the control method further includes:

[0014] When a high-voltage-on instruction is received, when the current in the main circuit is less than a preset current, a third disconnection instruction is generated. The third disconnection instruction is used to control the disconnection of the main circuit.

[0015] In an embodiment of the present application, the air-conditioning control circuit includes an air-conditioning relay. Wherein, the control method further includes:

[0016] When an air-conditioning power-on signal is received and the air-conditioning relay is free of faults, an air-conditioning relay closing instruction is generated after a second preset duration. The air-conditioning relay closing instruction is used to control the closing of the air-conditioning relay.

[0017] In an embodiment of the present application, the second preset duration is greater than or equal to 5S.

[0018] In an embodiment of the present application, the control method further includes:

[0019] When an air-conditioning power-off instruction is received, and after a third preset duration after determining that the main relay has been disconnected according to the status signal of the main relay transmitted by the air-conditioning thermal management system, a fourth disconnection instruction is generated. The fourth disconnection instruction is used to control the disconnection of the air-conditioning relay.

[0020] In an embodiment of the present application, the third preset duration is greater than or equal to 5S.

[0021] As a second aspect of the present application, the present application also provides a battery management system for a vehicle-mounted power battery, comprising:

[0022] A control circuit, the control circuit comprising a power battery, a high-voltage control circuit and an air-conditioning control circuit, the high-voltage control circuit comprising a pre-charging circuit and a main circuit connected in parallel with the pre-charging circuit, a capacitor and a load connected in parallel with the capacitor, and the power battery charges the capacitor through the pre-charging circuit and the main circuit to supply power to the load;

[0023] A controller is used to execute the above-mentioned control method of the vehicle-mounted power battery.

[0024] As a third aspect of the present application, the present application further provides a vehicle, comprising:

[0025] The battery management system described above;

[0026] A vehicle controller, the vehicle controller is connected to the controller;

[0027] An air conditioning thermal management system is connected to the air conditioning control circuit.

[0028] The present application provides a control method for a vehicle-mounted power battery, wherein a pre-charge circuit and a main circuit are arranged in a high-voltage control circuit, wherein the pre-charge circuit includes a pre-charge relay, and the main circuit includes a main negative relay. When the battery management system receives a high-voltage command sent by a vehicle controller, the pre-charge relay is controlled to be turned on and the main negative relay is turned off, and the power battery charges the capacitor through the pre-charge circuit for a first preset time; then the main negative relay is turned on, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit together; finally, when the voltage across the capacitor is close to the rated voltage of the power battery, the pre-charge relay is disconnected, so that the power battery supplies power to the load through the main circuit. That is, in the high-voltage power-on process, the capacitor is first pre-charged, and when the voltage across the capacitor is close to the rated voltage of the power battery, the main circuit is switched to supply power to the load. At this time, the impact current passing through the main negative relay is very small, which is completely within the tolerance range of the main negative relay and will not cause damage to the relay. Therefore, the main negative relay in the main circuit is protected, and the probability of safety hazards caused by adhesion of the main negative relay is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 This is a working principle diagram of a vehicle provided by an embodiment of the present application.

[0031] Figure 2 The figure shows a circuit diagram of a high-voltage control circuit provided by an embodiment of the present application.

[0032] Figure 3 The figure shows a schematic flowchart of a control method for an in-vehicle power battery provided by an embodiment of the present application.

[0033] Figure 4 The figure shows a graph of the voltage change across the capacitor during the high-voltage power-on process provided by an embodiment of the present application.

[0034] Figure 5 The figure shows a schematic flowchart of a control method for an in-vehicle power battery provided by another embodiment of the present application.

[0035] Figure 6 The figure shows a schematic flowchart of a control method for an in-vehicle power battery provided by another embodiment of the present application.

[0036] Figure 7 The figure shows a schematic flowchart of a control method for an in-vehicle power battery provided by another embodiment of the present application. Specific embodiments

[0037] The technical solution of the embodiment of the present application is applicable to the application scenario of powering on and off the power battery in a vehicle. The electric vehicle can be a passenger vehicle or a commercial vehicle. Figure 1 The figure shows a working principle diagram of a vehicle provided by an embodiment of the present application. As Figure 1 shown, the vehicle includes a control circuit of the power battery and a controller:

[0038] The vehicle controller 200. The vehicle controller 200 acts as a node in the CAN bus and plays a central role in information control in the network management of the whole vehicle. It communicates and exchanges data with various subsystems such as the motor controller and the battery management system through the CAN bus to enable the coordinated operation of various parts of the vehicle;

[0039] Battery management system 100, wherein the battery management system 100 includes a power battery 106, a control circuit 101 of the power battery, and a controller 102. The battery management system 100 can monitor parameters such as the voltage, current, and temperature of the battery pack in real time, estimate and analyze the state of the battery pack, and manage the charging and discharging process of the power battery in combination with the control instructions sent by the vehicle controller 200. Among them, the battery management system 100 includes a power battery 106, a controller 102, a high-voltage control circuit 103, and an air-conditioning control circuit 104. The power battery 106 supplies power to the load 107 through the high-voltage control circuit 103.

[0040] Air-conditioning thermal management system 300, and the air-conditioning thermal management system 300 is connected to the air-conditioning control circuit 104. The battery management system 100 can work in cooperation with the air-conditioning thermal management system 300 through the air-conditioning control circuit 104. For example, it can monitor the temperature state of the power battery 106 in real time and keep the battery pack at an appropriate working temperature by adjusting the working state of the air-conditioning thermal management system 300.

[0041] The high-voltage control circuit 103 includes a main negative relay, and the controller 102 is used to control the opening or closing of the relay to realize power supply to the load or power-off. During the use of the vehicle, after the vehicle key switch is turned on, the battery management system can receive a low-voltage wake-up signal. When the low-voltage wake-up signal is received, the battery management system performs a self-check. When the self-check result of the battery management system is fault-free and it receives the high-voltage command sent by the vehicle controller, it can control the main negative relay in the high-voltage control circuit to conduct according to the high-voltage command, so that the power battery supplies power to the load. However, the moment of power-on is equivalent to a short circuit, which will generate a very large inrush current. The inrush current is likely to cause the main negative relay to stick, resulting in difficulty in correctly disconnecting the high-voltage control circuit 103, thereby triggering safety hazards such as overheating, short circuit, and even fire of the power battery.

[0042] Based on the above technical status quo, the inventors of this application have conducted research and proposed: a pre-charge circuit and a main circuit are provided in the high-voltage control circuit 103. The pre-charge circuit includes a pre-charge relay, and the main circuit includes a main negative relay. When the battery management system receives the high-voltage command sent by the vehicle controller, it controls the pre-charge relay to conduct and the main negative relay to disconnect. The power battery charges the capacitor through the pre-charge circuit for a first preset duration; then the main negative relay conducts, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit together; finally, when the voltage across the capacitor is close to the rated voltage of the power battery, the pre-charge relay is disconnected, so that the power battery supplies power to the load through the main circuit. That is, during the high-voltage power-on process, the capacitor is first pre-charged. When the voltage across the capacitor is close to the rated voltage of the power battery, it is then switched to the main circuit to supply power to the load. At this time, the impact current passing through the main negative relay is very small, completely within the tolerance range of the main negative relay, and will not cause damage to the relay. Therefore, it plays a protective role for the main negative relay in the main circuit and reduces the probability of safety hazards caused by the adhesion of the main negative relay.

[0043] Optionally, as Figure 2 shown, the circuit diagram of the high-voltage control circuit provided by this application, as Figure 2 shown, the high-voltage control circuit provided by this application includes: a pre-charge circuit and a main circuit connected in parallel with the pre-charge circuit, a capacitor C, and a load. Among them, the capacitor C and the load are connected in parallel, and both ends of the capacitor C are respectively connected to the positive and negative electrodes of the power battery. Through the pre-charge circuit and the main circuit, the power battery charges the capacitor to supply power to the load.

[0044] Specifically, the pre-charge circuit includes a pre-charge relay K1 and a pre-charge resistor R. The main circuit includes a main negative relay K2. Among them, one end of the pre-charge relay K1 and one end of the main negative relay K2 are both connected to the negative electrode of the power battery. The other end of the pre-charge relay K1 is connected to one end of the pre-charge resistor R. The other end of the pre-charge resistor R and the other end of the main negative relay K2 are both connected to one end of the capacitor C. The other end of the capacitor C is connected to the positive electrode of the power battery.

[0045] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0046] As the first aspect of this application, this application provides a control method for an on-vehicle power battery. Figure 3 shown is a schematic flowchart of a control method for an on-vehicle power battery provided by an embodiment of this application, as Figure 3As shown in the figure, a control method for an in-vehicle power battery provided by the present application includes the following steps:

[0047] S1: When receiving the high-voltage command sent by the vehicle controller, generate a pre-charge command and a first disconnection command. The pre-charge command is used to control the pre-charge circuit to conduct and continuously conduct for a first preset duration, so that the power battery pre-charges the capacitor for the first preset duration. The first disconnection command is used to control the main circuit to disconnect;

[0048] Specifically, during the use of the vehicle, after the vehicle key switch is turned on, the battery management system can receive the low-voltage wake-up signal. When the battery management system receives the low-voltage wake-up signal, the battery management system performs a self-check. When the self-check result of the battery management system is no fault, it waits to receive the high-voltage command sent by the vehicle controller. Among them, the high-voltage command refers to controlling the power-on of the high-voltage system. When the battery management system receives the high-voltage command sent by the vehicle controller, it can generate a pre-charge command and a first disconnection command. The pre-charge command is used to control the pre-charge circuit to conduct and continuously conduct for a first preset duration, so that the power battery pre-charges the capacitor for the first preset duration. The first disconnection command is used to control the main circuit to disconnect. That is, during the high-voltage power-on process, the capacitor is first pre-charged for the first time. At this time, the main circuit is disconnected, and only the pre-charge circuit charges the capacitor.

[0049] Specifically, as Figure 2 shown, the pre-charge circuit includes a pre-charge relay K1, and the main circuit includes a main negative relay K2. Then the pre-charge command is to control the pre-charge relay K1 to conduct, so that the pre-charge circuit conducts. The first disconnection command is to control the main negative relay K2 to disconnect, so that the main circuit disconnects.

[0050] S2: When the power battery pre-charges the capacitor for the first preset duration, generate a main charge command. The main charge command is used to control the main circuit to conduct, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit, so that the voltage across the load is the first preset voltage, and the difference between the rated voltage of the power battery and the first preset voltage is less than the preset threshold;

[0051] Specifically, when the power battery pre-charges the capacitor for the first preset duration, generate a main charge command. The main charge command then controls the main circuit to conduct. At this time, the main circuit conducts, and the main circuit and the pre-charge circuit jointly charge the capacitor until the voltage across the capacitor is the first preset voltage. Specifically, as Figure 2 shown, the pre-charge circuit includes a pre-charge relay K1, and the main circuit includes a main negative relay K2. Then the main charge command is to control the main negative relay K2 to conduct, which also makes the main circuit conduct.

[0052] Since the capacitor has been pre-charged by the pre-charge circuit, when the main circuit is turned on at this time, the inrush current in the main circuit is relatively small. Therefore, the inrush current is within the capacity tolerance range of the main negative relay in the main circuit, and the main negative relay will not be adhered. Among them, the difference between the rated voltage of the power battery and the first preset voltage is less than the preset threshold, where the preset threshold is close to 0, that is, the first preset voltage is close to the rated voltage of the power battery.

[0053] Optionally, as Figure 2 shown, the pre-charge circuit includes a pre-charge relay K1 and a pre-charge resistor R connected in series with the pre-charge relay K1, and the main circuit includes a main negative relay K2. The first preset duration can be calculated according to

[0054] the capacitance value of the capacitor, the resistance value of the pre-charge resistor, and a preset constant, that is, the first preset duration T can be calculated according to the following formula (1):

[0055] T=nRC Formula (1);

[0056] In Formula (1), n is a preset constant, and RC is the time constant, and the time constant is the product of the resistance value R of the pre-charge resistor and the capacitance value C of the capacitor.

[0057] Optionally, n is 3-5.

[0058] S3: When the difference between the rated voltage of the power battery and the first preset voltage is less than the preset threshold, a second disconnection command is generated, and the second disconnection command is used to control the disconnection of the pre-charge circuit.

[0059] When the pre-charge circuit and the main circuit charge the capacitor at the same time, when the voltage across the capacitor is the first preset voltage, a second disconnection command is generated, and the second disconnection command is used to control the disconnection of the pre-charge circuit, that is, when the voltage across the capacitor is close to the rated voltage of the power battery, it can be controlled that only the main circuit charges the capacitor and supplies power to the load to realize the high-voltage power-on process.

[0060] Optionally, the first preset voltage can be determined according to the change curve of the capacitor during the high-voltage power-on process. After receiving the high-voltage command, when implementing the high-voltage power-on process using the above S1-S3, the voltage across the capacitor is detected at all times, and a voltage change curve graph is drawn, as Figure 4 shown. The voltage change amount of the voltage across the capacitor with time can be determined according to the voltage change curve graph, and the voltage corresponding to when the change amount with time tends to be stable is the first preset voltage.

[0061] Specifically, as Figure 2 shown, the pre-charge circuit includes a pre-charge relay K1, and the main circuit includes a main negative relay K2. Then the second disconnection command is to control the disconnection of the pre-charge relay K1, which also makes the pre-charge circuit disconnected.

[0062] A control method for an in-vehicle power battery provided by this application. When the battery management system receives a high-voltage power-on command sent by the vehicle controller, it controls the pre-charge relay to conduct and the main negative relay to disconnect. The power battery charges the capacitor through the pre-charge circuit for a first preset duration; then the main negative relay conducts, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit together; finally, when the voltage across the capacitor is close to the rated voltage of the power battery, the pre-charge relay is disconnected, so that the power battery supplies power to the load through the main circuit. That is, during the high-voltage power-on process, the capacitor is pre-charged first. When the voltage across the capacitor is close to the rated voltage of the power battery, it is switched to the main circuit to supply power to the load. At this time, the inrush current through the main negative relay is very small, completely within the tolerance range of the main negative relay, and will not cause damage to the relay. Therefore, it plays a protective role for the main negative relay in the main circuit and reduces the probability of safety hazards caused by the adhesion of the main negative relay.

[0063] In an embodiment of this application, as Figure 5 shown, after high-voltage power-on, that is, after S3 (when the difference between the rated voltage of the power battery and the first preset voltage is less than the preset threshold, a second disconnection command is generated, and the second disconnection command is used to control the disconnection of the pre-charge circuit), a control method for an in-vehicle power battery provided by this application further includes the following steps:

[0064] S4: When receiving a low-voltage power-off command, when the current in the main circuit is less than the preset current, a third disconnection command is generated, and the third disconnection command is used to control the disconnection of the main circuit.

[0065] When the battery management system is in the high-voltage power-on state in S3, when the battery management system fails or the vehicle key is turned off, after the vehicle controller cuts off the corresponding load at the vehicle end, it sends a low-voltage power-off command to the battery management system. After receiving the low-voltage power-off command sent by the vehicle controller, the battery management system detects the current in the main circuit, and when the current in the main circuit is less than the preset current, it controls the disconnection of the main circuit. Specifically, as Figure 2 shown, the main circuit includes the main negative relay K2, then disconnecting the main circuit is to disconnect the main negative relay K2 to complete the low-voltage power-off. After receiving the low-voltage power-off command in this application, it constantly detects the current in the main circuit and only cuts off the main negative relay in the main circuit when the current is less than the preset value to achieve safe power-off, prevent the relay from being cut off under load, and extend the service life of the relay.

[0066] In an embodiment of this application, as Figure 6 shown, a control method for an in-vehicle power battery provided by this application further includes the following steps:

[0067] S5: When an air conditioner power-on signal is received and the air conditioner relay has no fault, an air conditioner relay closing instruction is generated after a second preset duration, and the air conditioner relay closing instruction is used to control the air conditioner relay to close.

[0068] Specifically, when the battery management system receives a wake-up signal, it performs self-check on the battery management system. For example, it detects whether there is a fault in the air conditioner relay in the air conditioner control circuit. If there is a fault in the air conditioner relay, an air conditioner relay fault warning message is generated. If the air conditioner relay has no fault, then after the second preset duration when the air conditioner power-on signal is received, the air conditioner relay is closed to complete the air conditioner power-on process.

[0069] There is a pre-charge circuit at the input end of the rear-end air conditioner thermal management system connected to the air conditioner control circuit. Therefore, when the air conditioner relay closes directly without pre-charging, there will be no large inrush current. Therefore, after delaying the second preset duration when the air conditioner power-on signal is received, the air conditioner relay is closed. When the vehicle key is turned off and then turned on again, it ensures that the air conditioner system can complete the power-off process before re-powering on, avoiding the air conditioner relay being cut off under load, and thus ensuring that the air conditioner system can complete the power-off process and then re-power on when quickly powering on and off.

[0070] Optionally, the second preset duration is greater than or equal to 5S.

[0071] In an embodiment of the present application, as Figure 7 shown, after S5 (when an air conditioner power-on signal is received, an air conditioner relay closing instruction is generated after a second preset duration, and the air conditioner relay closing instruction is used to control the air conditioner relay to close), a control method for an on-vehicle power battery provided by the present application further includes the following steps:

[0072] S6: When an air conditioner power-off instruction is received and after a third preset duration when it is determined that the main relay has been disconnected according to the main relay signal transmitted by the air conditioner thermal management system, a fourth disconnection instruction is generated, and the fourth disconnection instruction is used to control the air conditioner relay to disconnect.

[0073] After the air conditioner is powered on, if a serious fault occurs in the battery management system or the vehicle key is turned off, the battery management system sends a power-off command for the air conditioner to the air-conditioning thermal management system. After receiving the power-off command for the air conditioner, the air-conditioning thermal management system cuts off the main relay and sends the status signal of the main relay to the battery management system. The battery management system then determines whether the main relay is disconnected based on the status signal of the main relay. If it is determined that the main relay has been disconnected, the air-conditioning relay is disconnected after a third preset time period to complete the power-off process of the air conditioner. If it is determined based on the status signal of the main relay that the main relay has not been successfully disconnected, the battery management system sends a power-off command for the air conditioner to the air-conditioning thermal management system. After receiving the power-off command for the air conditioner sent by the battery management system, the air-conditioning thermal management system disconnects the main relay again. Before disconnecting the air-conditioning relay, it is first detected whether a message signal indicating that the main relay has been determined to be disconnected is received, and the air-conditioning relay is disconnected within the third preset time period after it is determined that the main relay has been disconnected, avoiding the time difference that may exist between the message feedback and the actual working state of the main relay in the air-conditioning thermal management system, ensuring that the main relay in the air-conditioning thermal management system has been disconnected before cutting off the air-conditioning relay, thus avoiding the load-breaking cut-off of the air-conditioning relay and playing a protective role. In addition, the TMS main relay has been disconnected before the air-conditioning relay is cut off, avoiding the load-breaking cut-off of the air-conditioning relay and extending the service life.

[0074] Optionally, the third preset time period is greater than or equal to 5S.

[0075] Optionally, when a fault occurs in the battery management system or a wake-up signal is not received, the battery management system can also generate a power-off command for the air conditioner by itself and send the power-off command for the air conditioner to the air-conditioning thermal management system. After receiving the power-off command for the air conditioner sent by the battery management system, the air-conditioning thermal management system disconnects the main relay. The air-conditioning thermal management system sends the status signal of the main relay to the battery management system. The battery management system then determines whether the main relay is disconnected based on the main relay signal transmitted by the air-conditioning thermal management system. When it is determined that the main relay has been disconnected, a fourth disconnection command is generated after a third preset time period, that is, the air-conditioning relay is controlled to be disconnected.

[0076] As the second aspect of the present application, as Figure 1 shown, the present application further provides a battery management system for an on-vehicle power battery, including:

[0077] A high-voltage control circuit 103, the high-voltage control circuit 103 includes a pre-charge circuit and a main circuit connected in parallel with the pre-charge circuit, a capacitor, and a load connected in parallel with the capacitor. Through the pre-charge circuit and the main circuit, the power battery charges the capacitor to supply power to the load; specifically, as Figure 2 shown, the pre-charge circuit includes a pre-charge relay K1 and a pre-charge resistor R connected in series with the pre-charge relay K1, and the main circuit includes a main negative relay K2.

[0078] An air-conditioning control circuit 104; and

[0079] A controller 102 for executing the control method of the on-vehicle power battery described above.

[0080] For the battery management system of the on-vehicle power battery provided in this application, a pre-charge circuit and a main circuit are provided in the high-voltage control circuit. The pre-charge circuit includes a pre-charge relay, and the main circuit includes a main negative relay. When the battery management system receives the high-voltage command sent by the vehicle controller, it controls the pre-charge relay to conduct and the main negative relay to disconnect. The power battery charges the capacitor through the pre-charge circuit for a first preset duration; then the main negative relay conducts, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit together; finally, when the voltage across the capacitor is close to the rated voltage of the power battery, the pre-charge relay is disconnected again, so that the power battery supplies power to the load through the main circuit. That is, during the high-voltage power-on process, the capacitor is pre-charged first. When the voltage across the capacitor is close to the rated voltage of the power battery, it is switched to the main circuit to supply power to the load. At this time, the inrush current through the main negative relay is very small, completely within the tolerance range of the main negative relay, and will not damage the relay. Therefore, it plays a protective role for the main negative relay in the main circuit and reduces the probability of potential safety hazards caused by the adhesion of the main negative relay.

[0081] The method in this application can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in this application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, a core network device, an OAM, or other programmable devices.

[0082] The computer program product can be written in any combination of one or more programming languages to write program code for performing the operations of the embodiments of this application. The programming languages include object-oriented programming languages such as Java, C++, etc., and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed completely on the user computing device, partially on the user device, executed as an independent software package, partially on the user computing device and partially on a remote computing device, or executed completely on a remote computing device or server.

[0083] The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile types of storage media.

[0084] In addition, an embodiment of the present application can also be a storage medium on which a computer program is stored, and the computer program is executed by a processor to perform the steps in the control method of the vehicle-mounted power battery described in any of the above embodiments of this specification:

[0085] For the foregoing method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0086] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0087] The steps in the methods of the embodiments of the present application can be adjusted, combined, and deleted according to actual needs, and the technical features recorded in each embodiment can be replaced or combined. The devices in the embodiments of the present application can be combined, divided, and deleted according to actual needs.

[0088] Those skilled in the art may further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0089] The steps of the methods or algorithms described in combination with the embodiments disclosed herein can be directly implemented by hardware, software units executed by a processor, or a combination of both. The software units can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0090] Finally, it should also be noted that in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0091] The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for an in-vehicle power battery, characterized in that The control method is applicable to a battery management system, which includes a control circuit. The control circuit includes a power battery, an air-conditioning control circuit, and a high-voltage control circuit. The high-voltage control circuit includes a pre-charge circuit, a main circuit connected in parallel with the pre-charge circuit, a capacitor, and a load connected in parallel with the capacitor. Through the pre-charge circuit and the main circuit, the power battery charges the capacitor to supply power to the load; Wherein, the control method includes: When receiving a high-voltage command sent by the vehicle controller, a pre-charge command and a first disconnection command are generated. The pre-charge command is used to control the pre-charge circuit to conduct and continuously conduct for a first preset duration, so that the power battery pre-charges the capacitor for the first preset duration. The first disconnection command is used to control the main circuit to disconnect; When the power battery pre-charges the capacitor for the first preset duration, a main charge command is generated. The main charge command is used to control the main circuit to conduct, so that the power battery charges the capacitor through the pre-charge circuit and the main circuit, so that the voltage across the load is a first preset voltage, and the difference between the rated voltage of the power battery and the first preset voltage is less than a preset threshold; When the difference between the rated voltage of the power battery and the first preset voltage is less than the preset threshold, a second disconnection command is generated. The second disconnection command is used to control the pre-charge circuit to disconnect.

2. The control method according to claim 1, wherein The pre-charge circuit includes a pre-charge relay and a pre-charge resistor connected in series with the pre-charge relay; Wherein, the first preset duration is calculated according to the capacitance value of the capacitor, the resistance value of the pre-charge resistor, and a preset constant.

3. The control method according to claim 2, wherein The preset constant is 3 to 5.

4. The control method according to claim 1, wherein The control method further includes: When receiving a low-voltage command and the current in the main circuit is less than a preset current, a third disconnection command is generated. The third disconnection command is used to control the main circuit to disconnect.

5. The control method according to claim 1, wherein The air-conditioning control circuit includes an air-conditioning relay. Wherein, the control method further includes: When receiving an air-conditioning power-on signal and the air-conditioning relay has no fault, an air-conditioning relay closing command is generated after a second preset duration. The air-conditioning relay closing command is used to control the air-conditioning relay to close.

6. The control method according to claim 5, wherein The second preset duration is greater than or equal to 5S.

7. The control method according to claim 5, characterized in that The control method further includes: When receiving an air-conditioning power-off command and after a third preset duration determined according to the status signal of the main relay transmitted by the air-conditioning thermal management system to determine that the main relay has been disconnected, a fourth disconnection command is generated. The fourth disconnection command is used to control the air-conditioning relay to disconnect.

8. The control method according to claim 7, wherein The third preset duration is greater than or equal to 5S.

9. A battery management system for an in-vehicle power battery, characterized in that, Includes: A control circuit, the control circuit includes a power battery, a high-voltage control circuit, and an air-conditioning control circuit. The high-voltage control circuit includes a pre-charge circuit, a main circuit connected in parallel with the pre-charge circuit, a capacitor, and a load connected in parallel with the capacitor. Through the pre-charge circuit and the main circuit, the power battery charges the capacitor to supply power to the load; A controller for executing the control method of the on-vehicle power battery according to any one of claims 1-8 above.

10. A vehicle, characterized in that, Includes: The battery management system according to claim 9 The vehicle controller, and the vehicle controller is connected to the controller; The air-conditioning thermal management system, and the air-conditioning thermal management system is connected to the air-conditioning control circuit.

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