Power supply circuit and vehicle

Abstract

The utility model relates to a power supply circuit and a vehicle. The power supply circuit is applied to a vehicle and comprises a high-voltage battery module used for supplying power to a high-voltage system in the vehicle; the low-voltage battery module is used for supplying power to a low-voltage system in the vehicle; the input end of the first DCDC circuit is connected with the high-voltage battery module, the output end of the first DCDC circuit is connected with the low-voltage battery module, the output end of the first DCDC circuit is connected with the low-voltage system, and the working time of the first DCDC circuit is different from that of the high-voltage system. According to the technical scheme, the overall energy consumption of the vehicle can be reduced in the power supply process, and the service life of the low-voltage battery module in the power supply circuit can be prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of power supply, and in particular to a power supply circuit and a vehicle. Background Art

[0002] The low-voltage system of an electric vehicle is usually a 12V low-voltage system, and the power supply source of the low-voltage system is the 12V low-voltage battery of the vehicle (such as a 12V low-voltage storage battery or a 12V low-voltage lithium battery).

[0003] However, the capacity of the vehicle's 12V low-voltage battery is generally very small. In order to meet the power supply needs of the low-voltage system and prevent the vehicle's 12V low-voltage battery from feeding, a high-voltage intelligent power replenishment strategy is currently usually adopted. This strategy means that when the power level of the vehicle's 12V low-voltage battery is lower than a certain value, the vehicle's DCDC (Direct Current-Direct Current) and other high-voltage systems are activated to replenish the vehicle's 12V low-voltage battery.

[0004] However, the above method will increase the energy consumption of the electric vehicle and reduce the life of the 12V low-voltage battery of the vehicle. Utility Model Content

[0005] Based on this, an embodiment of the present application provides a power supply circuit and a vehicle, which can reduce the overall energy consumption of the vehicle during the power supply process and is beneficial to extending the life of the low-voltage battery module in the power supply circuit.

[0006] In a first aspect, the present application provides a power supply circuit. The power supply circuit is used in a vehicle, and the power supply circuit includes:

[0007] a high voltage battery module for supplying power to a high voltage system in the vehicle;

[0008] A low-voltage battery module for supplying power to a low-voltage system in the vehicle;

[0009] A first DCDC circuit, wherein an input end of the first DCDC circuit is connected to the high-voltage battery module, an output end of the first DCDC circuit is connected to the low-voltage battery module, and an output end of the first DCDC circuit is connected to the low-voltage system, and a working time of the first DCDC circuit is different from a working time of the high-voltage system.

[0010] In one embodiment, the power supply circuit also includes a BMS circuit, which is connected to the low-voltage battery module. The BMS circuit is also connected to the first DCDC circuit via a first wake-up hard line, a second wake-up hard line, a shutdown hard line and a CAN bus.

[0011] In one of the embodiments, the first DCDC circuit includes an MCU, a voltage conversion circuit and an auxiliary power supply;

[0012] The BMS circuit is connected to the input end of the auxiliary power supply through the first wake-up hard line, and the input end of the auxiliary power supply is also connected to the high-voltage battery module;

[0013] The MCU is connected to the output end of the auxiliary power supply and the voltage conversion circuit, and the MCU is connected to the BMS circuit via the second wake-up hard line, the shutdown hard line, and the CAN bus.

[0014] In one of the embodiments, the first DCDC circuit further includes a rectifier transformer circuit, an input end of the rectifier transformer circuit is connected to an output end of the auxiliary power supply, and an output end of the rectifier transformer circuit is connected to the MCU.

[0015] In one of the embodiments, the first DCDC circuit further includes a wake-up control circuit, the BMS circuit is connected to an input end of the wake-up control circuit via the first wake-up hard line, and an output end of the wake-up control circuit is connected to an input end of the auxiliary power supply.

[0016] In one of the embodiments, the first DCDC circuit further includes an input protection circuit and an output protection circuit;

[0017] The input end of the input protection circuit is connected to the high-voltage battery module, the output end of the input protection circuit is connected to the primary circuit of the transformer circuit, the input end of the output protection circuit is connected to the secondary circuit of the transformer circuit, and the output end of the output protection circuit is connected to the low-voltage battery module and the low-voltage system.

[0018] In one embodiment, the first DCDC circuit also includes a switch tube, a first end of the switch tube is connected to the output end of the input protection circuit, a second end of the switch tube is connected to the primary circuit of the transformer circuit, and a third end of the switch tube is connected to the output end of the wake-up control circuit.

[0019] In one embodiment, the first DCDC circuit further includes a parameter detection circuit and a protection circuit, the parameter detection circuit is connected to the MCU, and the protection circuit is connected to the MCU and the voltage conversion circuit.

[0020] In one of the embodiments, the power supply circuit further includes a second DCDC circuit, an input end of the second DCDC circuit is connected to the high-voltage battery module, and an output end of the second DCDC circuit is connected to the low-voltage battery module.

[0021] In a second aspect, an embodiment of the present application provides a vehicle, wherein the vehicle comprises a high voltage system, a low voltage system, and a power supply circuit as described in any one of the first aspects above.

[0022] The power supply circuit and the vehicle are applied to the vehicle, the power supply circuit includes a high-voltage battery module, a low-voltage battery module and a first DCDC circuit, the high-voltage battery module is used to power the high-voltage system in the vehicle, the low-voltage battery module is used to power the low-voltage system in the vehicle, the input end of the first DCDC circuit is connected to the high-voltage battery module, the output end of the first DCDC circuit is connected to the low-voltage battery module, and the output end of the first DCDC circuit is also connected to the low-voltage system, the working time of the first DCDC circuit is different from the working time of the high-voltage system, for example, when the high-voltage system is not started (that is, during the non-working time of the high-voltage system), the first DCDC circuit can perform voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage, and use the first power supply voltage to compete with the low-voltage battery module to power the low-voltage system without starting the entire high-voltage system, which greatly reduces the overall energy consumption of the vehicle; in addition, the first DCDC circuit and the low-voltage battery module can competitively power the low-voltage system, compared with the method in which only the low-voltage battery module powers the low-voltage system, the discharge times of the low-voltage battery module can be greatly reduced, which is conducive to extending the life of the low-voltage battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] FIG1 is a schematic diagram of a power supply circuit provided in an embodiment of the present application;

[0025] FIG2 is a schematic diagram of another power supply circuit provided in an embodiment of the present application;

[0026] FIG3 is a schematic diagram of another power supply circuit provided in an embodiment of the present application;

[0027] FIG4 is a schematic diagram of a first DCDC circuit and a BMS circuit provided in an embodiment of the present application;

[0028] Figure 5 A schematic diagram of another first DCDC circuit and a BMS circuit provided in an embodiment of the present application;

[0029] Figure 6 A schematic diagram of another first DCDC circuit and a BMS circuit provided in an embodiment of the present application;

[0030] Figure 7 A schematic diagram of another first DCDC circuit and a BMS circuit provided in an embodiment of the present application;

[0031] FIG. 8 is a schematic diagram of another power supply circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0034] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0035] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0036] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0037] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0038] The low-voltage system of an electric vehicle is usually a 12V low-voltage system, and the power supply source of the low-voltage system is the 12V low-voltage battery of the vehicle (such as a 12V low-voltage storage battery or a 12V low-voltage lithium battery). The power supply principle is as follows:

[0039] 1) Before the vehicle high-voltage to low-voltage system (i.e., vehicle DCDC) in an electric vehicle is activated, the vehicle's 12V low-voltage battery is used to power the low-voltage system;

[0040] 2) After the vehicle DCDC is activated, the vehicle DCDC and the vehicle 12V low-voltage battery jointly power the low-voltage system.

[0041] As electric vehicles become more and more intelligent, more and more functions need to be turned on when the electric vehicle is parked, such as car refrigerators, sentry mode, remote window opening and closing, etc., resulting in more and more energy consumption of the low-voltage system. These functions also need to be turned on before the electric vehicle is parked and the vehicle's DCDC is activated.

[0042] However, it can be seen from the above power supply principle that before the vehicle DCDC is activated, only the vehicle's 12V low-voltage battery supplies power to the low-voltage system, and the capacity of the vehicle's 12V low-voltage battery is generally very small, which cannot meet the power supply requirements of the low-voltage system when functions such as the car refrigerator and sentry mode are turned on, and there is also a risk of power feeding from the vehicle's 12V low-voltage battery.

[0043] In order to meet the power supply demand of the low-voltage system and prevent the vehicle's 12V low-voltage battery from feeding, a high-voltage intelligent power replenishment strategy is currently usually adopted. This strategy means that when the power level of the vehicle's 12V low-voltage battery is lower than a certain value, the vehicle's DCDC (Direct Current-Direct Current) and other high-voltage systems are activated, and the vehicle's 12V low-voltage battery is replenished with power from the high-voltage battery through the vehicle's DCDC.

[0044] However, the above-mentioned method of high-voltage intelligent charging will reduce the life of the vehicle's 12V low-voltage battery, and requires the activation of high-voltage systems such as the battery management system, vehicle controller, and vehicle DCDC, resulting in increased energy consumption of the vehicle. The high-voltage system will cause power consumption of the high-voltage battery and affect the vehicle's endurance.

[0045] In order to solve the above technical problems, the embodiments of the present application provide a power supply circuit and a vehicle. The technical solutions and beneficial effects provided by the embodiments of the present application are exemplarily introduced below in combination with the drawings.

[0046] Please refer to FIG. 1 . The power supply circuit shown in FIG. 1 is applied to a vehicle. The vehicle is, for example, an electric vehicle. Of course, it can also be other vehicles that require power supply from the power supply circuit. The following embodiments are all described by taking the vehicle being an electric vehicle as an example.

[0047] The power supply circuit includes a high-voltage battery module, a low-voltage battery module and a first DCDC circuit. The high-voltage battery module includes a high-voltage battery. After the high-voltage system in the vehicle is powered on, the high-voltage battery module is used to power the high-voltage system in the vehicle. The high-voltage system is mainly responsible for the vehicle's starting, driving, charging and discharging, air-conditioning power, etc.

[0048] The low-voltage battery module includes a low-voltage battery, which can be, for example, a 12V low-voltage battery in the vehicle, such as a 12V low-voltage storage battery or a 12V low-voltage lithium battery. The low-voltage battery module is used to power the low-voltage system in the vehicle, including the vehicle refrigerator, lighting system, air conditioning control system, etc.

[0049] In an embodiment of the present application, the first DCDC circuit can be a small DCDC circuit, the high-voltage input end of the first DCDC circuit is connected to the high-voltage battery module, the low-voltage output end of the first DCDC circuit is connected to the low-voltage battery module, and the low-voltage output end of the first DCDC circuit is connected to the low-voltage system, that is, the low-voltage output end of the first DCDC circuit is connected in parallel with the low-voltage battery module.

[0050] Among them, the working time of the first DCDC circuit is different from the working time of the high-voltage system, that is, when the high-voltage system is working, the first DCDC circuit is in a dormant state, and when the high-voltage system is not started (that is, during the non-working time of the high-voltage system), the first DCDC circuit can perform voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage, and use the first power supply voltage to compete with the low-voltage battery module to power the low-voltage system.

[0051] Please refer to Figure 1. After the vehicle is parked, the high-voltage system is powered off. K1 shown in Figure 1 is a positive relay, K2 is a pre-charge relay, R1 is a pre-charge resistor, and K3 is a negative relay. At this time, K1, K2, and K3 are disconnected, and the first DCDC circuit starts to work. When the high-voltage system is not started, the first DCDC circuit is used to perform voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage, and use the first power supply voltage to compete with the low-voltage battery module to supply power to the low-voltage system.

[0052] The following is an exemplary introduction to the process in which the first DCDC circuit uses the first power supply voltage to competitively supply power to the low-voltage system with the low-voltage battery module.

[0053] In an embodiment of the present application, the first DCDC circuit outputs a first power supply voltage at a constant voltage. For example, the first DCDC circuit stably outputs a voltage of 13.3V in a constant voltage mode. When the high-voltage system is just powered off, that is, when the first DCDC circuit starts working, the low-voltage battery module is fully charged, and the output voltage of the low-voltage battery module is greater than 13.3V. At this time, the low-voltage battery module first supplies power to the low-voltage system. As the power supply process continues, the output voltage of the low-voltage battery module also decreases until it decreases to 13.3V. At this time, the first power supply voltage output by the first DCDC circuit supplies power to the low-voltage system. If the power of the low-voltage system is large, the first DCDC circuit and the low-voltage battery module jointly supply power to the low-voltage system. When the output voltage of the low-voltage battery module is lower than 13.3V due to discharge, the first DCDC circuit will also supplement the power of the low-voltage battery module, thereby realizing the process in which the first DCDC circuit uses the first power supply voltage to competitively supply power to the low-voltage system with the low-voltage battery module.

[0054] It can be seen that the output end of the first DCDC circuit is connected to the low-voltage battery module and the low-voltage system. When the high-voltage system is not started, the first DCDC circuit can directly perform voltage conversion processing on the output voltage of the high-voltage battery module, so that it can compete with the low-voltage battery module to supply power to the low-voltage system without starting the entire high-voltage system, which greatly reduces the overall energy consumption of the vehicle. By the first DCDC circuit and the low-voltage battery module competitively supplying power to the low-voltage system, compared with the method of only the low-voltage battery module supplying power to the low-voltage system, the number of activations of the intelligent power replenishment strategy can be greatly reduced, that is, the number of discharges of the low-voltage battery module can be reduced, which is conducive to extending the life of the low-voltage battery module and protecting the low-voltage battery module.

[0055] As an implementation mode, based on the embodiment shown in Figure 1, referring to Figure 2, the power supply circuit of the embodiment of the present application also includes a second DCDC circuit, the input end of the second DCDC circuit is connected to the high-voltage battery module, and the output end of the second DCDC circuit is also connected to the low-voltage battery module.

[0056] The second DCDC circuit can be the whole vehicle DCDC in the vehicle, that is, the whole vehicle high voltage to low voltage system in the vehicle. The second DCDC circuit is used to perform voltage conversion processing on the output voltage of the high voltage battery module when the high voltage system is started, obtain the third power supply voltage, and use the third power supply voltage to power the low voltage battery module. That is, when the whole vehicle is to activate the high voltage system, K1 (positive relay) and K3 (negative relay) are closed, and the second DCDC circuit starts to work. At this time, the first DCDC circuit is dormant, and the second DCDC circuit is used to perform voltage conversion processing on the output voltage of the high voltage battery module when the high voltage system is started, obtain the third power supply voltage, and use the third power supply voltage to power the low voltage battery module.

[0057] If the high-voltage system is powered off, K1, K2, and K3 are disconnected, and the first DCDC circuit starts working. At this time, the second DCDC circuit is dormant. When the high-voltage system is not started, the first DCDC circuit is used to perform voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage, and use the first power supply voltage to compete with the low-voltage battery module to power the low-voltage system.

[0058] In the embodiment of the present application, the output end of the first DCDC circuit is connected to the low-voltage battery module and the low-voltage system. When the first DCDC circuit is working, the high-voltage system is powered off and the vehicle is in sleep mode. The first DCDC circuit can directly power its low-voltage system to meet the functional requirements of the vehicle in sleep mode and effectively prevent the low-voltage battery module from being fed. In addition, when the first DCDC circuit is working, it is not necessary to activate the vehicle controller, vehicle DCDC (such as the second DCDC circuit above) and other vehicle high-voltage systems, thereby greatly reducing the energy consumption of the vehicle while meeting the power supply of the vehicle's 12V low-voltage system.

[0059] In one embodiment, based on the embodiment shown in FIG. 2 , referring to FIG. 3 , the power supply circuit of this embodiment further includes a BMS (Battery Management System) circuit, the BMS circuit is connected to the output end of the first DCDC circuit, and the BMS circuit is also connected to a low-voltage battery module, and the low-voltage battery module can power the BMS circuit.

[0060] In an embodiment of the present application, the high-voltage battery module, the first DCDC circuit and the BMS circuit are packaged in the same battery pack, that is, the first DCDC circuit and the BMS circuit are both installed inside the high-voltage battery pack, which is conducive to the miniaturized design of the power supply system.

[0061] When the high-voltage system of the vehicle is to be activated, the BMS circuit controls K1 and K3 to close, and the second DCDC circuit starts to work. At this time, the first DCDC circuit is dormant, and the second DCDC circuit converts the output voltage of the high-voltage battery module to obtain a third power supply voltage, and uses the third power supply voltage to power the low-voltage battery module.

[0062] After the vehicle is parked, the high-voltage system is powered off, K1, K2, and K3 are disconnected, and when the high-voltage system is not started, the BMS circuit is used to control the first DCDC circuit to start working, that is, the first DCDC circuit can also work when the relay in the high-voltage battery pack is disconnected. The first DCDC circuit performs voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage. The first DCDC circuit uses the first power supply voltage to compete with the low-voltage battery module to power the low-voltage system.

[0063] In the embodiment of the present application, the first DCDC circuit is also used to power the BMS circuit using the first power supply voltage. In this way, even if the low-voltage battery module cannot normally power the BMS circuit due to some reasons, the BMS circuit can also obtain power through the first DCDC circuit, thereby improving the power supply reliability of the BMS circuit. The BMS circuit is a core component that ensures the normal operation of the battery pack and improves its performance and safety. Ensuring reliable power supply to the BMS circuit can improve the reliable operation of the entire power supply circuit.

[0064] The following is an exemplary introduction to the implementation of the BMS circuit controlling the first DCDC circuit to start working.

[0065] Please continue to refer to Figure 3. In addition to the low-voltage output end of the first DCDC circuit being connected to the BMS circuit, the BMS circuit is also connected to the first DCDC circuit through a first wake-up hard line, and the BMS circuit is also connected to the first DCDC circuit through a CAN (Controller Area Network) bus. The first DCDC circuit and the BMS circuit interact through the CAN bus.

[0066] The BMS circuit is used to send a first wake-up signal to the first DCDC circuit through a first wake-up hard line to wake up the first DCDC circuit when the high-voltage system is not started. The first wake-up signal can be a high-level signal, that is, the first wake-up hard line is used to carry the high-level hard line signal of the BMS circuit to wake up the first DCDC circuit.

[0067] After the vehicle is parked, the high-voltage system is powered off, and the BMS circuit sends a first wake-up signal to the first DCDC circuit through the first wake-up hard line. After receiving the first wake-up signal, the first DCDC circuit enters the wake-up state from the sleep state.

[0068] The BMS circuit is also used to send a first start-up instruction to the first DCDC circuit through the CAN bus. After the first DCDC circuit is awakened by the first wake-up signal, if the first DCDC circuit detects the first start-up instruction through the CAN bus, the first DCDC circuit starts working, that is, the first DCDC circuit performs voltage conversion processing on the output voltage of the high-voltage battery module.

[0069] In this way, after the vehicle is parked, the high-voltage system is powered off and before the vehicle DCDC (second DCDC circuit) is activated, that is, when the high-voltage system is not started, the BMS circuit sends a first wake-up signal to the first DCDC circuit through the first wake-up hard line, so as to conveniently wake up the first DCDC circuit, and then send a first start-up instruction to the first DCDC circuit through the CAN bus, so as to control the first DCDC circuit to start working and power the low-voltage system. The control process is simple and easy to implement.

[0070] As an implementation mode, the BMS circuit is also used to enter a sleep state after sending a first wake-up signal to the first DCDC circuit through a first wake-up hard line and sending a first start-up instruction to the first DCDC circuit through a CAN bus. In this way, when the first DCDC circuit is working, in addition to the high-voltage system not needing to be started, the BMS circuit also does not need to be started, further reducing the energy consumption of the entire vehicle.

[0071] In the embodiment of the present application, the BMS circuit is also connected to the first DCDC circuit through a second wake-up hard line and a shutdown hard line respectively. The functions of the second wake-up hard line and the shutdown hard line will be described in the following embodiments.

[0072] Taking into account that after the BMS circuit enters the sleep state, the BMS circuit also needs to calculate the SOC (State of Charge, also called the remaining power) of the high-voltage battery module. In view of this, in the embodiment of the present application, the first DCDC circuit is also used to obtain the power consumption data of the first DCDC circuit in each time period according to a preset time period during the working time period. At this time, the high-voltage system is not started, and the power consumption data is equivalent to the power consumed by the high-voltage battery module. The BMS circuit is also used to wake up according to the time period, and after waking up, perform SOC compensation calculation according to the power consumption data of the current time period. The time period is, for example, 1 hour, that is, the BMS circuit wakes up once every hour, reads the power calculated by the first DCDC circuit, and uses it for SOC compensation calculation, thereby realizing energy consumption management of the first DCDC circuit.

[0073] The following is an exemplary introduction to a partial circuit structure inside the first DCDC circuit.

[0074] Based on the embodiment shown in FIG. 3 , referring to FIG. 4 , the first DCDC circuit includes an MCU, a voltage conversion circuit and an auxiliary power supply.

[0075] The MCU is connected to the output end of the auxiliary power supply and the voltage conversion circuit. The MCU is connected to the BMS circuit via the CAN bus. The BMS circuit is connected to the input end of the auxiliary power supply via the first wake-up hard line.

[0076] As described above, when the high-voltage system is not started, the BMS circuit sends a first wake-up signal to the first DCDC circuit through the first wake-up hard line. If the auxiliary power supply detects the first wake-up signal through the first wake-up hard line, it supplies power to the MCU, so that the MCU enters the wake-up state from the sleep state.

[0077] Optionally, the auxiliary power supply immediately supplies power to the MCU after detecting the first wake-up signal; Optionally, the auxiliary power supply does not immediately supply power to the MCU after detecting the first wake-up signal, but continues to detect the first wake-up signal through the first wake-up hard line. If the first wake-up signal continues for a preset time, power is supplied to the MCU, which can increase the wake-up reliability. As an implementation method, a MOS switch tube (MOS1 as shown in FIG. 4) is also provided between the auxiliary power supply and the BMS circuit to turn on or off the signal path between the auxiliary power supply and the BMS circuit.

[0078] After being awakened by the auxiliary power supply, if the MCU detects the first start-up instruction sent by the BMS circuit through the CAN bus, the first DCDC circuit starts to work, and the first DCDC circuit enables the transformer circuit, that is, the first DCDC circuit controls the transformer circuit to perform voltage conversion processing on the output voltage of the high-voltage battery module, and stably outputs a voltage of 13.3V in a constant voltage mode, thereby powering the low-voltage system.

[0079] In an embodiment of the present application, the input end of the auxiliary power supply is also connected to the high-voltage battery module, and the high-voltage battery module is also used to charge the auxiliary power supply. In this way, the low-voltage power supply of the MCU in the first DCDC circuit is provided by the auxiliary power supply on the high-voltage side.

[0080] Please continue to refer to Figure 4. The first DCDC circuit also includes a rectifier and transformer circuit. The input end of the rectifier and transformer circuit is connected to the output end of the auxiliary power supply, and the output end of the rectifier and transformer circuit is connected to the MCU. The rectifier and transformer circuit is used to rectify and transform the output voltage of the auxiliary power supply to obtain a second power supply voltage, and use the second power supply voltage to power the MCU. The second power supply voltage can be, for example, 12V.

[0081] The high voltage of the high voltage battery module is converted into low voltage through an auxiliary power supply and a rectifier transformer circuit to power the MCU. The first DCDC circuit does not need to be powered by the low voltage battery module. Even if the low voltage battery module is damaged, the first DCDC circuit can still work, which increases safety.

[0082] Based on the embodiment shown in FIG. 4, see Figure 5 The first DCDC circuit also includes a wake-up control circuit. In this embodiment, the wake-up control circuit detects the first wake-up signal and determines whether to wake up the MCU.

[0083] The output end of the wake-up control circuit is connected to the input end of the auxiliary power supply, and the BMS circuit is connected to the input end of the wake-up control circuit through a first wake-up hard line. The wake-up control circuit is used to control the auxiliary power supply to supply power to the MCU if a first wake-up signal is detected through the first wake-up hard line, so that the MCU enters a wake-up state from a sleep state.

[0084] Optionally, the wake-up control circuit immediately controls the auxiliary power supply to supply power to the MCU after detecting the first wake-up signal; optionally, the wake-up control circuit does not immediately control the auxiliary power supply to supply power to the MCU after detecting the first wake-up signal, but continues to detect the first wake-up signal through the first wake-up hard line. If the first wake-up signal continues for a preset time, the auxiliary power supply is controlled to supply power to the MCU, which can increase the wake-up reliability. As an implementation method, a MOS switch tube is also provided between the wake-up control circuit and the BMS circuit to turn on or off the signal path between the wake-up control circuit and the BMS circuit.

[0085] Please continue to see Figure 5 In this embodiment, the first DCDC circuit also includes an input protection circuit, the input end of the input protection circuit is connected to the high-voltage battery module, and the output end of the input protection circuit is connected to the primary circuit of the transformer circuit. The input protection circuit can protect the input end of the first DCDC circuit.

[0086] The first DCDC circuit also includes a switch tube (such as Figure 5 MOS2 shown in the figure), the first end of the switch tube is connected to the output end of the input protection circuit, the second end of the switch tube is connected to the primary circuit of the transformer circuit, and the third end of the switch tube is connected to the output end of the wake-up control circuit.

[0087] The wake-up control circuit is also used to turn on the switch tube if a first wake-up signal is detected through the first wake-up hard line, that is, the wake-up control circuit controls the auxiliary power supply to supply power to the MCU. When waking up the MCU, the power supply path between the transformer circuit and the high-voltage battery module is synchronously turned on. In this way, after the MCU is awakened, if the MCU detects the first start-up instruction sent by the BMS circuit through the CAN bus, the first DCDC circuit starts working, that is, the first DCDC circuit controls the transformer circuit to perform voltage conversion processing on the output voltage of the high-voltage battery module, and stably outputs a voltage of 13.3V in a constant voltage mode, thereby powering the low-voltage system.

[0088] Optionally, the first DCDC circuit also includes an output protection circuit, the input end of the output protection circuit is connected to the secondary circuit of the transformer circuit, and the output end of the output protection circuit is connected to the low-voltage battery module and the low-voltage system. The output protection circuit can protect the output end of the first DCDC circuit.

[0089] The above embodiment mainly introduces the MCU, auxiliary power supply, and wake-up control circuit in the first DCDC circuit. The first DCDC circuit is further introduced below. Figure 5 Based on the examples shown, see Figure 6The MCU is also connected to the BMS circuit through a closing hard line and a second wake-up hard line respectively. The first DCDC circuit also includes a parameter detection circuit and a protection circuit. The parameter detection circuit is connected to the MCU, and the protection circuit is connected to the MCU and the voltage conversion circuit.

[0090] When the first DCDC circuit is working, the parameter detection circuit is used to detect the circuit parameters and environmental parameters of the first DCDC circuit. Exemplarily, the parameter detection circuit can detect the circuit parameters and environmental parameters of the first DCDC circuit in real time, where the circuit parameters include the input voltage, output voltage, and output current of the first DCDC circuit, and the environmental parameters include circuit temperature, etc.

[0091] The MCU is also used to control the protection circuit to perform circuit protection on the first DCDC circuit when it is determined according to circuit parameters and environmental parameters that the first DCDC circuit has a fault. For example, the MCU determines according to the circuit parameters that there is an input overvoltage, an output overvoltage, an output undervoltage, or an output overcurrent, and then determines that the first DCDC circuit has a fault. The MCU determines according to environmental parameters that the circuit temperature is too high, and then determines that the first DCDC circuit has a fault. The MCU then controls the protection circuit to perform circuit protection on the first DCDC circuit, for example, by shutting off the low-voltage output of the first DCDC circuit.

[0092] As described above, after the BMS circuit controls the first DCDC circuit to start working, the BMS circuit enters a dormant state. During the operation of the first DCDC circuit, if the MCU determines that the first DCDC circuit has a fault,

[0093] The MCU is also used to send a second wake-up signal to the BMS through a second wake-up hard line to wake up the BMS circuit. Similar to the first wake-up signal, the second wake-up signal may also be a high-level signal.

[0094] The BMS circuit is also used to send a shutdown instruction to the MCU by closing the hard line or CNA bus after being awakened by the second wake-up signal. The shutdown instruction is used to instruct the MCU to prohibit the voltage transformation circuit from performing voltage conversion processing on the output voltage of the high-voltage battery module and to cut off the auxiliary power supply to the MCU's power supply circuit, that is, the shutdown instruction is used to shut down the first DCDC circuit.

[0095] In this way, when the first DCDC circuit is working, if the MCU determines that there is a fault in the first DCDC circuit according to relevant parameters, the BMS circuit is awakened in time, and the BMS circuit turns off the first DCDC circuit to implement fault management of the first DCDC circuit, which is beneficial to improving the power supply safety of the power supply system.

[0096] It should be noted that the above embodiments and the accompanying drawings only illustrate some components / circuits in the first DCDC circuit. In other possible implementations, the first DCDC circuit may also include other components. Figure 7 , Figure 7 The phase-shifted full-bridge circuit and the synchronous rectification circuit shown are the voltage conversion circuits mentioned above. Figure 7 The DC input voltage detection circuit, voltage and current detection circuit, and temperature detection circuit shown are the parameter detection circuits described above. The DC input voltage detection circuit can detect the input voltage of the first DCDC circuit, the voltage and current detection circuit can detect the output voltage and output current of the first DCDC circuit, and the temperature detection circuit can detect the circuit temperature.

[0097] Please continue to see Figure 7 The first DCDC circuit may also include an isolation drive circuit, a phase-shift full-bridge control circuit, a synchronous rectification control circuit and an anti-reverse circuit. The phase-shift full-bridge control circuit is used to control the phase-shift full-bridge circuit, and the synchronous rectification control circuit is used to control the synchronous rectification circuit.

[0098] In this way, by designing the first DCDC circuit inside the high-voltage battery pack, the high-voltage system is powered off after the vehicle is parked, K1, K2, and K3 are disconnected, and when the high-voltage system is not started, the BMS circuit controls the first DCDC circuit to start working. The first DCDC circuit performs voltage conversion processing on the output voltage of the high-voltage battery module to obtain a first power supply voltage. The first DCDC circuit uses the first power supply voltage to compete with the low-voltage battery module to power the low-voltage system.

[0099] When the high-voltage system of the whole vehicle is to be activated, the BMS circuit controls K1 and K3 to close, and the second DCDC circuit starts to work. When the high-voltage system is started, the BMS circuit sends a shutdown command to the MCU by closing the hard line or the CNA bus. After the MCU detects the shutdown command by closing the hard line or the CNA bus, it turns off the low-voltage output of the first DCDC circuit and cuts off the auxiliary power supply, so that the first DCDC circuit is dormant. The second DCDC circuit performs voltage conversion processing on the output voltage of the high-voltage battery module to obtain a third power supply voltage, and uses the third power supply voltage to power the low-voltage battery module.

[0100] After the high-voltage system is started, the high-voltage battery may experience thermal runaway. In this case, the water circulation function needs to be turned on to cool the high-voltage battery to prevent the heat from spreading. However, when the high-voltage battery thermally runs away, the high-voltage system needs to be disconnected. The current 12V low-voltage battery of the vehicle cannot support the power supply of the water pump for a long time due to its small capacity.

[0101] In order to solve this problem, in an embodiment of the present application, the BMS circuit is also used to send a third wake-up signal to the first DCDC circuit through a first wake-up hard line to wake up the first DCDC circuit when the high-voltage battery module is in thermal runaway, and send a second start-up instruction to the first DCDC circuit through the CAN bus.

[0102] The first DCDC circuit is also used to start working if a second start-up instruction is detected through the CAN bus. The first DCDC circuit performs voltage conversion on the output voltage of the high-voltage battery module to obtain a power supply voltage, and uses the power supply voltage to power the water pump. That is, when the high-voltage battery module is in thermal runaway, the first DCDC circuit will be forced to turn on to power the water pump to prevent heat diffusion of the high-voltage battery pack, thereby improving the safety of the entire power supply circuit.

[0103] The following is a further description of the solution provided by the embodiment of the present application in conjunction with FIG8. The input control loop shown in FIG8 may include Figure 7 The output control loop shown in FIG8 may include a phase-shifted full-bridge circuit, a phase-shifted full-bridge control circuit, an isolation drive circuit, a wake-up control circuit, etc. Figure 7 The synchronous rectification circuit, synchronous rectification control circuit, etc. shown.

[0104] The control process of the first DCDC circuit is as follows:

[0105] 1) After the vehicle is parked, the high-voltage system is powered off, the K1, K2, and K3 relays are disconnected, the BMS circuit wakes up the first DCDC circuit through the first wake-up hard line, and sends a start command to the first DCDC circuit through the CAN bus.

[0106] Alternatively, when the high-voltage system is started and the BMS circuit detects a thermal runaway fault, the BMS circuit wakes up the first DCDC circuit through a first wake-up hard line and sends a start instruction to the first DCDC circuit through the CAN bus.

[0107] 2) After the first DCDC circuit detects the wake-up signal of the first wake-up hard line, the auxiliary power supply in the first DCDC circuit supplies power to the MCU in the first DCDC circuit.

[0108] 3) After the MCU is awakened, the MCU detects the start-up command sent by the BMS circuit through the CAN bus, enables the high-low voltage conversion circuit, and stably outputs a voltage of 13.3V in constant voltage mode, competing with the low-voltage battery module to power the low-voltage system.

[0109] 4) When the vehicle is started, the high-voltage system is powered on, the K1 and K3 relays are closed, and the BMS circuit sends a shutdown signal to the MCU through the closing hard line and sends a shutdown command to the MCU through the CAN bus.

[0110] 5) After the MCU detects a shutdown signal of the hard line or a shutdown command sent by the BMS circuit through the CAN bus, the low-voltage output of the first DCDC circuit is turned off and the auxiliary power supply is cut off.

[0111] The fault management process of the first DCDC circuit is as follows:

[0112] 1) When the first DCDC circuit is working, the MCU detects the input voltage, output voltage, output current, body temperature and other information in real time.

[0113] 2) If faults such as input overvoltage, output overvoltage, output undervoltage, output overcurrent, and body overtemperature are detected, the MCU shuts down the low-voltage output of the first DCDC circuit within the specified time and wakes up the BMS circuit through the second wake-up hard line.

[0114] 3) After the BMS circuit detects the wake-up signal of the second wake-up hard line, it turns off the first DCDC circuit by turning off the hard line and the CAN bus signal.

[0115] The energy consumption management process of the first DCDC circuit is as follows:

[0116] 1) When the first DCDC circuit is working, the accumulated high-voltage side power consumed in each time period (one hour is one time period) (power consumption data) is calculated.

[0117] 2) The BMS circuit wakes up every hour and reads the power calculated by the first DCDC circuit for SOC compensation calculation.

[0118] In the above embodiment, when the first DCDC circuit is working, the low-voltage output end of the first DCDC circuit is directly connected to the low-voltage battery module (12V low-voltage battery of the whole vehicle), which can directly power the low-voltage battery module, solve the functional requirements of the whole vehicle in the sleep mode, and effectively prevent the low-voltage battery module from being fed.

[0119] When the first DCDC circuit is working, the high-voltage system of the vehicle does not need to be started, nor does the BMS circuit need to be started, which greatly reduces the energy consumption of the vehicle. The low-voltage power supply of the first DCDC circuit is provided by the auxiliary power supply on the high-voltage side, and does not require the power supply of the low-voltage battery module. In the case of damage to the low-voltage battery module, the first DCDC circuit can also work, which increases safety.

[0120] In one embodiment, a vehicle is provided, comprising a high voltage system, a low voltage system and a power supply circuit as described in any one of the above embodiments. The vehicle is, for example, an electric vehicle, and of course, may also be other vehicles that require power supply from the power supply circuit.

[0121] The relevant implementation methods and beneficial effects of the vehicle in the embodiment of the present application and the relevant implementation methods and beneficial effects of the power supply circuit above can be found in the relevant description above and will not be repeated here.

[0122] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0123] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A power supply circuit, characterized in that: Applied to a vehicle, the power supply circuit comprises: a high voltage battery module for supplying power to a high voltage system in the vehicle; A low-voltage battery module for supplying power to a low-voltage system in the vehicle; A first DCDC circuit, wherein an input end of the first DCDC circuit is connected to the high-voltage battery module, an output end of the first DCDC circuit is connected to the low-voltage battery module, and an output end of the first DCDC circuit is connected to the low-voltage system, and a working time of the first DCDC circuit is different from a working time of the high-voltage system.

2. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes a BMS circuit, which is connected to the low-voltage battery module. The BMS circuit is also connected to the first DCDC circuit via a first wake-up hard line, a second wake-up hard line, a shutdown hard line and a CAN bus.

3. The power supply circuit according to claim 2, characterized in that: The first DCDC circuit includes an MCU, a voltage conversion circuit and an auxiliary power supply; The BMS circuit is connected to the input end of the auxiliary power supply through the first wake-up hard line, and the input end of the auxiliary power supply is also connected to the high-voltage battery module; The MCU is connected to the output end of the auxiliary power supply and the voltage conversion circuit, and the MCU is connected to the BMS circuit via the second wake-up hard line, the shutdown hard line, and the CAN bus.

4. The power supply circuit according to claim 3, characterized in that: The first DCDC circuit also includes a rectifier and transformer circuit, an input end of the rectifier and transformer circuit is connected to an output end of the auxiliary power supply, and an output end of the rectifier and transformer circuit is connected to the MCU.

5. The power supply circuit according to claim 3, characterized in that: The first DCDC circuit further includes a wake-up control circuit, the BMS circuit is connected to an input end of the wake-up control circuit via the first wake-up hard line, and an output end of the wake-up control circuit is connected to an input end of the auxiliary power supply.

6. The power supply circuit according to claim 5, characterized in that: The first DCDC circuit also includes an input protection circuit and an output protection circuit; The input end of the input protection circuit is connected to the high-voltage battery module, the output end of the input protection circuit is connected to the primary circuit of the transformer circuit, the input end of the output protection circuit is connected to the secondary circuit of the transformer circuit, and the output end of the output protection circuit is connected to the low-voltage battery module and the low-voltage system.

7. The power supply circuit according to claim 6, characterized in that: The first DCDC circuit also includes a switch tube, a first end of the switch tube is connected to the output end of the input protection circuit, a second end of the switch tube is connected to the primary circuit of the transformer circuit, and a third end of the switch tube is connected to the output end of the wake-up control circuit.

8. The power supply circuit according to any one of claims 3 to 7, characterized in that: The first DCDC circuit further includes a parameter detection circuit and a protection circuit. The parameter detection circuit is connected to the MCU, and the protection circuit is connected to the MCU and the voltage conversion circuit.

9. The power supply circuit according to claim 1, characterized in that: The power supply circuit further includes a second DCDC circuit, an input end of the second DCDC circuit is connected to the high voltage battery module, and an output end of the second DCDC circuit is connected to the low voltage battery module.

10. A vehicle, characterized in that: It comprises a high voltage system, a low voltage system and a power supply circuit as claimed in any one of claims 1 to 9.

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