Charging Circuit, System, Charging Method, Vehicle and Storage Medium

Abstract

The present application relates to a charging circuit, a system, a charging method, a vehicle and a storage medium. The charging circuit includes a power battery and an electric drive module; a high-voltage box of the power battery respectively connected to the power battery and the electric drive module, and the high-voltage box is also connected to a DC charging port. A DC boost charging component is integrated in the high-voltage box, and DC boost charging of the power battery is realized through the DC boost charging component and the electric drive module. Thus, the problems in the related art are solved, such as using an external boost device or circuit control for boost charging, which increases the redundancy and failure rate of the system, reduces the safety and stability of the system, or using the vehicle drive system to construct a fast charge boost circuit, which increases the manufacturing cost and layout difficulty of the vehicle, etc.

Description

Technical Field

[0001] This application relates to the technical field of DC charging for electric vehicles, and particularly to a charging circuit, a system, a charging method, a vehicle, and a storage medium. Background Art

[0002] Currently, the charging methods for power batteries of electric vehicles are mainly divided into two types: AC slow charging and DC fast charging. Among them, AC slow charging is achieved by connecting an on-vehicle charger to the national grid, using the AC charging circuit formed by the on-vehicle charger to convert the AC power of the national grid into DC power matching the battery voltage and then charging the power battery. DC fast charging is achieved by connecting to a DC charging device through a DC charging interface. After the DC charging device converts the AC power of the national grid into DC power, it directly supplies the power battery through the DC charging circuit.

[0003] However, with the increase in battery voltage, when the rated voltage of the charging pile is lower than the voltage of the power battery, DC charging of the vehicle cannot be carried out. Currently, most of the voltage platforms of domestic DC chargers are 500V and below, and electric vehicles with battery voltages higher than the charger voltage cannot be directly charged.

[0004] In related technologies, the mainstream technical solutions for DC boost charging of electric vehicles are to add a boost device and a boost circuit or to construct a fast charge boost circuit using the vehicle drive system. However, adding a boost device and a boost circuit increases the system redundancy and failure rate by adding a control circuit board in the boost device alone to control the boost charging process, reducing the system safety and robustness. Constructing a fast charge boost circuit using the vehicle drive system adds a fast charge boost control box in the boost circuit, increasing the manufacturing cost of the whole vehicle and the layout difficulty of vehicle design. Summary of the Invention

[0005] This application provides a charging circuit, a system, a charging method, a vehicle, and a storage medium to solve the problems in related technologies that using an external boost device or circuit to control boost charging increases the system redundancy and failure rate, reduces the system safety and stability, or using the vehicle drive system to construct a fast charge boost circuit increases the manufacturing cost and layout difficulty of the vehicle.

[0006] In a first aspect embodiment of this application, a charging circuit is provided, including: a power battery and an electric drive module; a high-voltage box of the power battery respectively connected to the power battery and the electric drive module, and the high-voltage box is also connected to a DC charging port. Among them, a DC boost charging component is integrated in the high-voltage box, and DC boost charging of the power battery is achieved through the DC boost charging component and the electric drive module.

[0007] According to the above technical means, in the embodiment of the present application, the DC boost charging component and the electric drive module integrated in the high-voltage box are used to perform DC boost charging on the power battery, realizing the automation of DC boost charging, thereby reducing the system failure rate, improving the system stability and safety, with a simple overall structure, avoiding the additional installation of a boost device, and reducing the vehicle manufacturing cost and layout difficulty.

[0008] Optionally, the DC boost charging component includes a boost relay, a first capacitor, and a capacitor relay. Among them, one end of the boost relay is connected to one end of the DC charging port, the other end of the boost relay is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the capacitor relay, the other end of the capacitor relay is connected to the other end of the DC charging port, and the other end of the boost relay is also connected to the electric drive module through the center line.

[0009] According to the above technical means, in the embodiment of the present application, the automation of DC boost charging can be realized through the DC boost charging component.

[0010] Optionally, the DC boost charging component further includes a discharge resistor, where the discharge resistor is connected in parallel across the two ends of the first capacitor to discharge the voltage of the first capacitor.

[0011] According to the above technical means, the discharge resistor in the embodiment of the present application is used to discharge the voltage of the capacitor connected in parallel therewith, so as to ensure the high-voltage safety of the system.

[0012] Optionally, a DC charging component is also integrated in the high-voltage box, and the DC charging of the power battery is realized through the DC charging component, or the DC boost charging of the power battery is realized through the DC charging component, the DC boost charging component, and the electric drive module.

[0013] According to the above technical means, a DC charging component is also integrated in the high-voltage box in the embodiment of the present application. The DC charging of the power battery is realized through the DC charging component, or the DC boost charging of the power battery is realized through the DC charging component, the DC boost charging component, and the electric drive module. The charging mode can be switched according to actual needs, making the charging more automated, thereby reducing the system failure rate and improving the system stability and safety.

[0014] Optionally, the DC charging component includes a DC relay, a main positive relay, and a main negative relay. Among them, one end of the DC relay is respectively connected to one end of the DC boost charging component and one end of the DC charging port. The other end of the DC relay is connected to one end of the main negative relay. The other end of the main negative relay is connected to the negative electrode of the power battery. The positive electrode of the power battery is connected to one end of the main positive relay. The other end of the main positive relay is respectively connected to the other end of the DC boost charging component and the other end of the DC charging port.

[0015] According to the above technical means, in the embodiment of the present application, the DC charging of the power battery can be realized through the DC charging component.

[0016] Optionally, the DC charging component further includes a pre-charge relay and a pre-charge resistor. Among them, one end of the pre-charge relay is connected to one end of the main positive relay. The other end of the pre-charge relay is connected to one end of the pre-charge resistor. The other end of the pre-charge resistor is connected to the other end of the main positive relay.

[0017] Optionally, the DC charging component further includes a fuse, and the fuse is arranged between the power battery and the main positive relay.

[0018] According to the above technical means, the fuse in the embodiment of the present application is used to protect the circuit. After the current exceeds the specified value for a period of time, the fuse melts the fuse wire by the heat generated by itself, thereby disconnecting the circuit.

[0019] In the second aspect of the present application, an embodiment provides a charging system, including: a charging circuit as described in any one of the above embodiments; a battery management system, configured to identify the maximum allowable output voltage of the charging pile after the charging circuit is connected to the charging pile. If the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery, otherwise control the charging circuit to perform DC boost charging on the power battery.

[0020] In the third aspect of the present application, an embodiment provides a vehicle, including the charging system as described in the above embodiment.

[0021] In the fourth aspect of the present application, an embodiment provides a method for charging a power battery. The method uses a charging circuit integrated with a DC boost charging component and a DC charging component to perform DC charging or DC boost charging on the power battery. Among them, the method includes the following steps: after the charging circuit is connected to the charging pile, obtain the maximum allowable output voltage of the charging pile; if the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery, otherwise control the charging circuit to perform DC boost charging on the power battery.

[0022] Optionally, the charging circuit further includes an electric drive module. Controlling the charging circuit to perform DC boost charging on the power battery includes: after the power battery goes high voltage during DC boost charging, sending a voltage transformation requirement instruction to the charging pile and a buck instruction to the electric drive module. Wherein, the electric drive module enters a buck mode according to the buck instruction, and buck-boosts the output voltage of the power battery to a voltage matching the voltage of the charging pile;

[0023] After successfully shaking hands with the charging pile, send a boost instruction to the electric drive module. Wherein, the electric drive module enters a boost mode according to the boost instruction, and performs DC boost charging on the power battery through the electric drive module and the DC boost charging component.

[0024] Optionally, the DC boost charging component includes a boost relay, a first capacitor, and a capacitor relay, and the DC charging component includes a DC relay, a main positive relay, and a main negative relay. Wherein, a first sampling point is provided between the main positive relay and the DC charging port, a second sampling point is provided between the DC relay and the DC charging port, a third sampling point is provided between the capacitor relay and the first capacitor, and a fourth sampling point is provided between the boost relay and the first capacitor.

[0025] Optionally, after the power battery goes high voltage during DC boost charging, it further includes: obtaining the voltages of the first to fourth sampling points; calculating a first voltage between the third sampling point and the fourth sampling point, a second voltage between the first sampling point and the fourth sampling point, and a third voltage between the first sampling point and the second sampling point according to the voltages of the first to fourth sampling points; when the high voltage of the power battery is activated, the vehicle is not performing DC charging, and the closing instruction of the capacitor relay is not issued, if the first voltage is equal to the second voltage, it is determined that the capacitor relay has an adhesion fault; when the high voltage of the power battery is activated, the vehicle is not performing DC charging, the capacitor relay does not have an adhesion fault, and the closing instruction of the boost relay is not issued, if the first voltage is equal to the third voltage, it is determined that the boost relay has an adhesion fault.

[0026] An embodiment of the fifth aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement the charging method of the power battery as described in the above embodiment.

[0027] The beneficial effects of the embodiments of the present application:

[0028] (1) In the embodiment of the present application, a DC boost charging component and an electric drive module integrated in a high-voltage box are used to perform DC boost charging on a power battery, realizing the automation of DC boost charging, thereby reducing the system failure rate, improving the system stability and safety. The overall structure is simple, avoiding the additional installation of a boost device, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0029] (2) The embodiment of the application can realize DC boost charging of the power battery through the DC boost charging component.

[0030] (3) The discharge resistor in the embodiment of the present application is used to discharge the voltage of the capacitor connected in parallel therewith, so as to ensure the high-voltage safety of the system.

[0031] (4) In the embodiment of the present application, a DC charging component is also integrated in the high-voltage box. The DC charging of the power battery is realized through the DC charging component, or the DC boost charging of the power battery is realized through the DC charging component, the DC boost charging component and the electric drive module. The charging mode can be switched according to actual needs, making the charging more automated, thereby reducing the system failure rate and improving the system stability and safety.

[0032] (5) In the embodiment of the present application, the DC charging of the power battery can be realized through the DC charging component.

[0033] (6) The fuse in the embodiment of the present application is used to protect the circuit. After the current exceeds the specified value for a period of time, the fuse melts due to the heat generated by itself, thereby disconnecting the circuit.

[0034] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0035] The above-mentioned and / or additional aspects and advantages of the present application will become apparent and be easily understood from the following description of the embodiments in conjunction with the drawings, wherein:

[0036] Figure 1 Schematic diagram of the boost device provided by the prior art;

[0037] Figure 2 Schematic diagram of the principle of constructing a boost circuit for a three-phase motor of a vehicle drive system provided by the prior art;

[0038] Figure 3 Structural diagram of a charging circuit provided according to an embodiment of the present application;

[0039] Figure 4 Principle block diagram of the charging circuit provided according to an embodiment of the present application;

[0040] Figure 5Structural diagram of a charging system provided according to an embodiment of the present application;

[0041] Figure 6 Flow chart of a charging method for a power battery provided according to an embodiment of the present application;

[0042] Figure 7 Schematic diagram of voltage sampling points on the high - voltage loop of a charging circuit provided according to an embodiment of the present application;

[0043] Figure 8 Schematic diagram of DC boost charging logic provided according to an embodiment of the present application.

[0044] Wherein: 10 - charging circuit, 100 - power battery, 200 - electric drive module, 300 - high - voltage box, F1 - fuse, R1 - pre - charge resistor, K4 - main positive relay, K5 - pre - charge relay, K6 - main negative relay, C1 - first capacitor, R2 - discharge resistor, K1 - boost relay, K2 - DC relay, K3 - capacitor relay, C - first sampling point, E - second sampling point, F - third sampling point, G - fourth sampling point. Detailed implementation manners

[0045] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application.

[0046] With the rapid development and popular application of electric vehicles, the improvement of driving range, driving performance, and charging efficiency has become the focus of attention for consumers and electric vehicle manufacturers. The most direct and effective way is to increase the voltage platform of the power battery. Currently, domestic mainstream electric vehicle manufacturers are all planning to produce electric vehicles with a 750V high - battery - voltage platform. However, the voltage platform of the current DC chargers for electric vehicles is mostly 500V or less. As the battery voltage increases, when the rated voltage of the charging pile is lower than the voltage of the power battery, DC charging of the vehicle cannot be carried out.

[0047] Currently, the mainstream technical solutions for DC boost charging in the electric vehicle market are to add a boost device and a boost circuit or to construct a fast - charge boost circuit using the vehicle drive system.

[0048] In related technology (1), this application designed a boost device using a boost inductor, a high - voltage relay, a high - voltage filter component, a thin - film capacitor, a control circuit, and a fixed support. One end is connected to the DC charging pile, and the other end is connected to the power battery. The specific structure Figure 1As shown in the figure; a support shielding plate is provided above the boost inductor, and a control circuit board is provided above the support shielding plate. The relay, the negative relay, and the positive relay are all connected to the control circuit board; the charging pile current is boosted by this boosting device and then input into the power battery for charging. In this boosting charging solution, because a control circuit board is separately added to the boosting device to control the boosting charging process, the system redundancy and failure rate are increased, and the system safety and robustness need to be improved.

[0049] In the related art (2), this application includes using a fast charging boost control box, a high-voltage power battery, a motor controller, and a three-phase drive motor to form a DC boost charging circuit, as Figure 2 shown in the figure; during the boosting process, the negative pole of the DC charging pile is conducted with the negative pole of the power battery, and the positive pole output of the charging pile first flows through the fast charging boost control box, the three-phase drive motor, and then enters the battery to boost charge the battery. This solution uses the three-phase motor of the vehicle drive system to build a boost circuit, but a fast charging boost control box is separately added to the boost circuit, thereby increasing the manufacturing cost of the whole vehicle and the layout difficulty of vehicle design.

[0050] Next, the charging circuit, system, charging method, vehicle, and storage medium of the embodiments of the present application will be described with reference to the accompanying drawings. Specifically, Figure 3 is a structural diagram of a charging circuit provided by an embodiment of the present application.

[0051] As Figure 3 shown in the figure, the charging circuit 10 includes: a power battery 100, an electric drive module 200, and a high-voltage box 300 of the power battery.

[0052] Among them, the high-voltage box 300 is respectively connected to the power battery 100 and the electric drive module 200, and the high-voltage box is also connected to the DC charging port. Among them, a DC boost charging component is integrated in the high-voltage box 300, and the DC boost charging of the power battery 100 is realized through the DC boost charging component and the electric drive module 200.

[0053] It can be understood that in the embodiments of the present application, the DC boost charging of the power battery 100 is realized through the DC boost charging component and the electric drive module 300 integrated in the high-voltage box 300, realizing the automation of DC boost charging, thereby reducing the failure rate of the system, improving the system stability and safety, the overall structure is simple, avoiding the additional installation of a boosting device, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0054] Specifically, the charging logic is as follows: when it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, the DC boost charging process is entered. The boost charging logic is to first collect and determine whether the required voltage conditions are met. If they are met, under this condition, the battery management system requests the electric drive to output a voltage matching the charging pile voltage, and enters the charging handshake stage. Subsequently, the battery management system sends a request boost command to the electric drive, the electric drive enters the boost mode, and the charging pile starts to output at high power, realizing the DC boost charging function.

[0055] In the embodiment of the present application, as Figure 4 shown, the DC boost charging component includes a boost relay K1, a first capacitor C1, and a capacitor relay K3.

[0056] Among them, one end of the boost relay K1 is connected to one end of the DC charging port, the other end of the boost relay K1 is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is connected to one end of the capacitor relay K3, the other end of the capacitor relay K3 is connected to the other end of the DC charging port, and the other end of the boost relay K1 is also connected to the electric drive module 300 through the center line.

[0057] It can be understood that the embodiment of the present application can realize the automation of DC boost charging through the DC boost charging component.

[0058] Specifically, when it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage and the charging mode is the DC boost charging mode at this time, first collect and determine the voltages at both ends of the capacitor relay K3 and the boost relay K1, and close the capacitor relay K3 and the boost relay K1 after meeting the determination conditions.

[0059] It should be noted that the determination conditions are as follows: first, the battery management system determines that when the voltage CF across the first capacitor C1 or the voltage CG across the boost relay K1 collected and the voltage difference between the voltage CF across the first capacitor C1 is less than a certain value for a certain period of time, then control to close the capacitor relay K3. Subsequently, when it is determined that the voltage across the boost relay K1 is less than a certain value for a certain period of time compared with the DC charging port voltage, then close the boost relay K1. Then close the main positive relay K4 and the main negative relay K6, and send a high-voltage command to the battery. The first capacitor C1 releases the capacitor voltage through the parallel discharge resistor R2, and is consumed in the form of heat through the discharge resistor R2 to ensure the high-voltage safety of the system.

[0060] In the embodiment of the present application, as Figure 4 shown, the DC boost charging component further includes a discharge resistor R2.

[0061] Among them, the discharge resistor R2 is connected in parallel across the two ends of the first capacitor C1 to discharge the voltage of the first capacitor C1.

[0062] It can be understood that the discharge resistor R2 in the embodiment of the present application is used to discharge the voltage of the capacitor connected in parallel therewith, so as to ensure the high-voltage safety of the system.

[0063] In the embodiment of the present application, as Figure 4 shown, a DC charging component is also integrated in the high-voltage box 300, and the DC charging of the power battery 100 is realized through the DC charging component, or the DC boost charging of the power battery 100 is realized through the DC charging component, the DC boost charging component and the electric drive module 200.

[0064] It can be understood that the embodiment of the present application can switch the charging mode according to actual needs, realize the DC charging of the power battery 100 through the DC charging component, and realize the DC boost charging of the power battery 100 through the DC charging component, the DC boost charging component and the electric drive module 200, making the charging more automated, thereby reducing the failure rate of the system and improving the stability and safety of the system.

[0065] It should be noted that the DC boost charging additional device in the DC boost charging component is connected and fixed to the battery high-voltage box through a copper bar with the DC charging component, so that the battery management system can freely drive and control each charging component, automatically identify DC charging and DC boost charging and enter the charging process.

[0066] Specifically, the charging mode is divided into a DC charging mode and a DC boost charging mode. Before executing the corresponding mode, it is necessary to judge the magnitude between the maximum allowable output voltage of the charging pile and the battery voltage. The charging logic is as follows: after the charging gun is inserted and swiped for charging, when it is recognized that the maximum allowable output voltage of the charging pile is greater than the battery voltage, the battery management system is used to control the DC charging component to directly charge the power battery 100 with DC; when it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, the battery management system is used to control the DC boost charging component, the DC charging component and the electric drive module 200 to enter the DC boost charging mode to boost-charge the power battery 100.

[0067] In the embodiment of the present application, as Figure 4 shown, the DC charging component includes a DC relay K2, a main positive relay K4 and a main negative relay K6.

[0068] Wherein, one end of the DC relay K2 is respectively connected to one end of the DC boost charging component and one end of the DC charging port, the other end of the DC relay K2 is connected to one end of the main negative relay K6, the other end of the main negative relay K6 is connected to the negative electrode of the power battery 300, the positive electrode of the power battery 300 is connected to one end of the main positive relay K4, and the other end of the main positive relay K4 is respectively connected to the other end of the DC boost charging component and the other end of the DC charging port.

[0069] It can be understood that in the embodiments of the present application, the DC charging of the power battery 100 can be achieved through the DC charging component.

[0070] Specifically, the charging logic based on the above components is as follows: After the charging gun is inserted and the card is swiped for charging, when it is recognized that the maximum allowable output voltage of the charging pile is greater than the battery voltage, the boost relay K1 and the capacitor relay K3 are disconnected, and the DC relay K2, the main positive relay K4, and the main negative relay K6 are closed, and the charging pile directly charges the power battery with DC power; when it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, the DC boost charging process is entered. The boost charging logic is to first collect and judge the voltages at both ends of the capacitor relay K3 and the boost relay K1. After meeting the judgment conditions, the capacitor relay K3 and the boost relay K1 are closed, and then the main positive relay K4 and the main negative relay K6 are closed.

[0071] In the embodiments of the present application, as Figure 4 shown, the DC charging component further includes a pre-charge relay K5 and a pre-charge resistor R1.

[0072] Wherein, one end of the pre-charge relay K5 is connected to one end of the main positive relay K4, the other end of the pre-charge relay K5 is connected to one end of the pre-charge resistor R1, and the other end of the pre-charge resistor is connected to the other end of the main positive relay K4.

[0073] In the embodiments of the present application, as Figure 4 shown, the DC charging component further includes a fuse F1.

[0074] Wherein, the fuse F1 is arranged between the power battery 100 and the main positive relay K4.

[0075] It can be understood that the fuse in the embodiments of the present application is used to protect the circuit.

[0076] It should be noted that when the current in the circuit exceeds the specified value, the fuse melts the fuse wire by the heat generated by itself, so as to disconnect the circuit and achieve the purpose of protecting the circuit.

[0077] According to the charging circuit proposed in the embodiments of the present application, the DC boost charging of the power battery is realized through the DC boost charging component and the electric drive module integrated in the high-voltage box, realizing the automation of DC boost charging, thereby reducing the failure rate of the system, improving the stability and safety of the system, with a simple overall structure, avoiding the additional installation of a boost device, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0078] Next, the charging circuit will be elaborated in conjunction with Figure 4 wherein, the DC boost charging component can be the first switch module, and the DC charging component can be the second switch module. The following embodiments can all be elaborated using this description, specifically as follows:

[0079] Both the first switch module and the second switch module are integrated and fixed inside the high-voltage box of the power battery pack. After integration, they are connected to the electric drive module through the center line L1 and the electric drive output line. Specifically, one end of the center line is respectively connected to the boost relay K1, the voltage stabilizing capacitor C1, and the discharge resistor R2. Inside the power battery, the negative copper row of the DC charging port is directly connected to the a terminal of the boost relay K1 and then to the a terminal of the fast charge relay K2. The center line L1 is connected to the b terminal of the boost relay K1 through a copper row inside the power battery. The positive terminal of the DC charging port is directly connected to the positive electric drive output and the main positive relay K4 through a copper row inside the battery pack. The discharge resistor R2 and the voltage stabilizing capacitor C1 are connected in parallel. After parallel connection, one end is connected to the b terminal of the boost relay K1 through a copper row, and the other parallel end is connected to the a terminal of the capacitor relay K3. The b terminal of the capacitor relay K3 is connected to the a terminal of the main positive relay K4, that is, connected to the positive terminal of the DC charging port and the positive electric drive output.

[0080] Through the above connection method, the DC boost charging components including the boost relay K1, the capacitor relay K3, the voltage stabilizing capacitor C1, and the discharge resistor R2 are integrated inside the high-voltage box of the power battery, and are connected to the electric drive module through the electric drive output port and the center line L1 to achieve the DC boost charging function. After both the first switch module and the second switch module are integrated inside the power battery, the opening and closing controls of the capacitor relay K3 and the boost relay K1 are uniformly controlled by the battery management system, which can realize the automated operation of DC boost charging and at the same time reduce the redundancy and failure points of the system.

[0081] The specific working principle of boost charging is as follows: After the charging gun is inserted and the card is swiped for charging, when it is recognized that the maximum allowable output voltage of the charging pile is greater than the battery voltage, the boost relay K1 and the capacitor relay K3 of the DC boost charging component are controlled to disconnect, and the DC relay K2 is controlled to close. The main positive relay K4 and the main negative relay K6 of the DC charging component are controlled to close, and the charging pile directly charges the power battery with DC. When it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, the DC boost charging process is entered. The boost charging logic is to first collect and judge the voltages at both ends of the capacitor relay K3 and the boost relay K1 of the DC boost charging component. After meeting the judgment conditions, the capacitor relay K3 and the boost relay K1 of the DC boost charging component are closed, and then the main positive relay K4 and the main negative relay K6 of the DC charging component are closed, and the battery-on-high-voltage command is sent.

[0082] Under these conditions, the battery management system sends a variable voltage demand voltage command to the charging pile and a request for voltage reduction command to the electric drive. After the charging variable voltage mode state of the electric drive changes to the voltage reduction mode, the battery output voltage is stepped down by the electric drive and then a voltage matching that of the charging pile is output from the electric drive, so that the voltage across the voltage stabilizing capacitor C1 matches the variable voltage demand voltage sent by the battery management system. According to national standards requirements, the charging pile enters the handshaking stage, and at this time, the charging pile can output externally.

[0083] Subsequently, the battery management system sends a request for voltage boost command to the electric drive. The electric drive responds and the charging variable voltage mode state of the electric drive changes to the voltage boost mode. The battery management system corrects the requested voltage and requested current for the charging pile. The output at the a end of the charging pile directly enters the battery pack through the main positive relay K4. The output at the b end of the charging pile flows through K1 and the center line into the electric drive for voltage boost. After the electric drive outputs current, it enters the power battery through the main negative relay K6, realizing the function of DC voltage boost charging. After entering normal DC voltage boost charging, the battery management system controls K1 to disconnect. The voltage stabilizing capacitor C1 releases the capacitor voltage through the shunt discharge resistor R2, and the energy is consumed in the form of heat through the discharge resistor R2 to ensure the high-voltage safety of the system.

[0084] Next, a charging system according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0085] Figure 5 It is a block diagram of the charging system according to an embodiment of the present application.

[0086] As Figure 5 shown, the charging system 20 includes: a charging circuit 10 and a battery management system 30.

[0087] Among them, the battery management system 30 is used to identify the maximum allowable output voltage of the charging pile after the charging circuit 10 is connected to the charging pile. If the maximum allowable output voltage is greater than the battery voltage of the power battery 100, it controls the charging circuit to perform DC charging on the power battery 100. Otherwise, it controls the charging circuit to perform DC voltage boost charging on the power battery 100.

[0088] It should be noted that the foregoing explanation of the charging circuit embodiment also applies to the charging system of this embodiment, and will not be repeated here.

[0089] For the charging system according to an embodiment of the present application, after the charging circuit is connected to the charging pile, it identifies the maximum allowable output voltage of the charging pile. If the maximum allowable output voltage is greater than the battery voltage of the power battery, it uses the battery management system to control the charging circuit to perform DC charging on the power battery. Otherwise, it uses the battery management system to control the charging circuit to perform DC voltage boost charging on the power battery, thereby reducing the failure rate of the system, improving the stability and safety of the system, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0090] An embodiment of the present application further provides a vehicle, including a charging system as described in the above embodiment.

[0091] Figure 6 It is a charging method for a power battery according to an embodiment of the present application.

[0092] As Figure 6 shown, this charging method for the power battery uses a charging circuit integrated with a DC boost charging component and a DC charging component to perform DC charging or DC boost charging on the power battery. Among them, the method includes the following steps:

[0093] In step S101, after the charging circuit is connected to the charging pile, obtain the maximum allowable output voltage of the charging pile.

[0094] It can be understood that in the embodiment of the present application, after the charging circuit is connected to the charging pile, the maximum allowable output voltage of the charging pile is obtained, so as to facilitate subsequent judgment of the magnitude relationship between the maximum allowable output voltage and the voltage of the power battery, and select the corresponding charging mode.

[0095] In step S102, if the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery; otherwise, control the charging circuit to perform DC boost charging on the power battery.

[0096] It can be understood that in the embodiment of the present application, when the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery; otherwise, control the charging circuit to perform DC boost charging on the power battery, thereby reducing the failure rate of the system, improving the stability and safety of the system, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0097] Specifically, as Figure 4 shown, the charging logic includes: after the charging gun is inserted and the card is swiped for charging, when it is recognized that the maximum allowable output voltage of the charging pile is greater than the battery voltage, control the boost relay K1 and the capacitor relay K3 of the DC boost charging component to disconnect, and the DC relay K2 to close. Control the main positive relay K4 and the main negative relay K6 of the DC charging component to close, and the charging pile directly performs DC charging on the power battery. When it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, enter the DC boost charging process. The boost charging logic is to first collect and judge the voltages at both ends of the capacitor relay K3 and the boost relay K1 of the DC boost charging component, and after meeting the judgment conditions, close the capacitor relay K3 and the boost relay K1 of the DC boost charging component, and then close the main positive relay K4 and the main negative relay K6 of the DC charging component.

[0098] In the embodiment of the present application, the charging circuit further includes an electric drive module for controlling the charging circuit to perform DC boost charging on the power battery, including: after the power battery goes high voltage during the DC boost charging process, sending a voltage transformation requirement instruction to the charging pile and a step-down instruction to the electric drive module. Wherein, the electric drive module enters the step-down mode according to the step-down instruction, and steps down the output voltage of the power battery to a voltage matching the voltage of the charging pile; after successfully shaking hands with the charging pile, sending a boost instruction to the electric drive module. Wherein, the electric drive module enters the boost mode according to the boost instruction, and performs DC boost charging on the power battery through the electric drive module and the DC boost charging component.

[0099] It can be understood that in the embodiment of the present application, the battery management system sends corresponding instructions to the charging pile and the electric drive module to adjust and correct the voltage and current input into the power battery by the charging pile in real time, so as to implement the DC boost charging function.

[0100] In the embodiment of the present application, as Figure 7 shown, the DC boost charging component includes a boost relay, a first capacitor and a capacitor relay, and the DC charging component includes a DC relay, a main positive relay and a main negative relay. Wherein, a first sampling point C is arranged between the main positive relay and the DC charging port, a second sampling point E is arranged between the DC relay and the negative pole of the DC charging port, a third sampling point F is arranged between the capacitor relay K3 and the capacitor C1, and a fourth sampling point G is arranged between the main negative relay K6 and the capacitor C1.

[0101] It can be understood that in the embodiment of the present application, sampling points are set to judge the conditions of the charging steps and diagnose faults in the boost charging process. The purpose is to be able to make corresponding fault handling in time when the boost components fail to improve system safety.

[0102] Specifically, as Figure 7 shown, the A sampling point is arranged between the battery module and the b terminal of the main positive relay K4, the B sampling point is arranged between the battery module and the b terminal of the main negative relay K6, the C sampling point is arranged between the a terminal of the main positive relay K4 and the positive pole of the DC charging port, the D sampling point is arranged between the main negative relay K6 and the fast charging relay, the E point is arranged between the boost relay K1 and the negative pole of the DC charging port, the F point is arranged between the capacitor relay K3 and the voltage stabilizing capacitor C1, and the G point is arranged between the boost relay K1 and the step-down capacitor.

[0103] In the embodiment of the present application, as Figure 7As shown, after the power battery is under high voltage during the DC boost charging process, the following steps are further included: obtaining the voltages at the first to fourth sampling points; calculating the first voltage between the third sampling point and the fourth sampling point, the second voltage between the first sampling point and the fourth sampling point, and the third voltage between the first sampling point and the second sampling point based on the voltages at the first to fourth sampling points; when the high voltage of the power battery is activated, the vehicle is not undergoing DC charging, and the closing instruction for the capacitor relay K3 is not issued, if the first voltage is equal to the second voltage, it is determined that the capacitor relay K3 has an adhesion fault; when the high voltage of the power battery is activated, the vehicle is not undergoing DC charging, the capacitor relay K3 does not have an adhesion fault, and the closing instruction for the boost relay K1 is not issued, if the first voltage is equal to the third voltage, it is determined that the boost relay K1 has an adhesion fault.

[0104] It can be understood that in the embodiment of the present application, voltage acquisition is performed through a high-voltage connection copper bar, and the designed voltage sampling points are used to determine the conditions and diagnose faults in the charging steps of the boost charging process. When a fault occurs in the boost component, corresponding fault handling can be promptly performed to improve system safety.

[0105] Specifically, as Figure 7 shown, the voltage between points F and G can be used to diagnose whether the voltage inside the voltage stabilizing capacitor is safely discharged; under the condition that the battery high voltage is activated, the vehicle is not undergoing DC charging, and the BMS does not issue a closing instruction for the capacitor relay, comparing the voltage between points F and G with the voltage between points C and G can determine whether the capacitor relay is adhered; under the condition that the battery high voltage is activated, the vehicle is not undergoing DC charging, the BMS does not issue a closing instruction for the boost relay, and no fast charge relay adhesion fault is reported, corresponding diagnosis is performed by combining the voltages between points C and E and the voltages between points C and G to determine whether the boost relay is adhered.

[0106] According to the charging method of the power battery proposed in the embodiment of the present application, when the maximum allowable output voltage is greater than the battery voltage of the power battery, the charging circuit is controlled to perform DC charging on the power battery; otherwise, the charging circuit is controlled to perform DC boost charging on the power battery, thereby reducing the system failure rate, improving system stability and safety, and reducing the manufacturing cost and layout difficulty of the vehicle.

[0107] Next, the charging method of the power battery will be elaborated in detail in combination with Figure 8 as follows:

[0108] After the charging gun is plugged in and the card is swiped for charging, when it is recognized that the maximum allowable output voltage of the charging pile is greater than the battery voltage, the boost relay K1 and the capacitor relay K3 are disconnected, and K2, K4, and K6 are closed. The charging pile directly charges the power battery with direct current; when it is recognized that the maximum allowable output voltage of the charging pile is less than the battery voltage, the direct current boost charging process is entered. The specific charging process is as follows: First, the BMS determines that the voltage CF across the voltage stabilizing capacitor C1 or the voltage CG across the boost relay K1 and the voltage CF across the voltage stabilizing capacitor C1 have a difference less than a certain value for a certain period of time, and then controls the closing of the capacitor relay K3. Subsequently, it is determined that the voltage across the boost relay K1 and the direct current charging port voltage are less than a certain value for a certain period of time, and then the boost relay K1 is closed. Then, the main positive relay K4 and the main negative relay K6 are closed, and a high-voltage command for the battery is sent; under this condition, the battery management system sends a variable voltage demand voltage command to the charging pile and at the same time sends a request for voltage reduction command to the electric drive. After the electric drive charging variable voltage mode state becomes the voltage reduction mode, the battery output voltage is reduced by the electric drive and a voltage matching the charging pile voltage is output from the electric drive, so that the voltage across the voltage stabilizing capacitor C1 matches the variable voltage demand voltage sent by the battery management system, thereby entering a handshake stage with the charging pile. At this time, the charging pile can output externally; subsequently, the battery management system sends a request for voltage boost command to the electric drive, the electric drive responds and the electric drive charging variable voltage mode state becomes the voltage boost mode. The battery management system corrects the requested voltage and requested current for the charging pile. The output of the a end of the charging pile directly enters the battery pack through K4. The output of the b end of the charging pile flows into the electric drive through K1 and the center line for voltage boost. After the electric drive outputs current, it enters the power battery through K6, realizing the direct current boost charging function; after entering normal direct current boost charging, the battery management system controls K1 to disconnect. The voltage stabilizing capacitor C1 releases the capacitor voltage through the parallel discharge resistor R2, and is consumed in the form of heat through the discharge resistor R2 to ensure the high-voltage safety of the system.

[0109] The embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the charging method of the power battery as described above is implemented.

[0110] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or N embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0111] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0112] Any process or method description shown in a flowchart or described otherwise herein can be understood to represent a module, segment, or portion of code including one or N executable instructions for implementing a customized logical function or process. And the scope of the preferred embodiments of the present application includes additional implementations, where functions can be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the technical field of the embodiments of the present application.

[0113] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays, field programmable gate arrays, etc.

[0114] Those of ordinary skill in the art of the present technology can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0115] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A charging circuit, characterized in that, it includes: a power battery and an electric drive module; a high-voltage box of the power battery respectively connected to the power battery and the electric drive module, the high-voltage box is also connected to a DC charging port, wherein a DC boost charging component is integrated in the high-voltage box, and the DC boost charging of the power battery is realized through the DC boost charging component and the electric drive module; a DC charging component is also integrated in the high-voltage box; both the DC boost charging component and the DC charging component are integrated and fixed in the high-voltage box of the power battery, the DC boost charging component includes a boost relay, a first capacitor and a capacitor relay, wherein, one end of the boost relay is connected to one end of the DC charging port, the other end of the boost relay is connected to one end of the first capacitor, the other end of the first capacitor is connected to one end of the capacitor relay, the other end of the capacitor relay is connected to the other end of the DC charging port, and the other end of the boost relay is also connected to the electric drive module through a center line; the DC boost charging component further includes a discharge resistor, wherein the discharge resistor is connected in parallel across the two ends of the first capacitor to discharge the voltage of the first capacitor; the DC charging component includes a DC relay, a main positive relay and a main negative relay, wherein, one end of the DC relay is respectively connected to one end of the DC boost charging component and one end of the DC charging port, the other end of the DC relay is connected to one end of the main negative relay, the other end of the main negative relay is connected to the negative electrode of the power battery, the positive electrode of the power battery is connected to one end of the main positive relay, and the other end of the main positive relay is respectively connected to the other end of the DC boost charging component and the other end of the DC charging port; inside the power battery pack, the negative copper row of the DC charging port is directly connected to one end of the boost relay and then connected to one end of the DC relay, and the center line is connected to the other end of the boost relay through a copper row inside the power battery; the positive electrode of the DC charging port is directly connected to the output positive electrode of the electric drive module and the main positive relay through a copper row inside the power battery pack, one end of the discharge resistor after being connected in parallel with the first capacitor is connected to the other end of the boost relay through a copper row, and the other end after parallel connection is connected to one end of the capacitor relay; the other end of the capacitor relay is connected to one end of the main positive relay.

2. The charging circuit according to claim 1, characterized in that, the DC charging of the power battery is realized through the DC charging component, or the DC boost charging of the power battery is realized through the DC charging component, the DC boost charging component and the electric drive module.

3. The charging circuit according to claim 1, characterized in that, the DC charging component further includes a pre-charge relay and a pre-charge resistor, wherein, one end of the pre-charge relay is connected to one end of the main positive relay, the other end of the pre-charge relay is connected to one end of the pre-charge resistor, and the other end of the pre-charge resistor is connected to the other end of the main positive relay.

4. The charging circuit according to claim 1, wherein, the DC charging component further includes a fuse, and the fuse is arranged between the power battery and the main positive relay.

5. A charging system, wherein, it includes: a charging circuit as described in any one of claims 1-4; a battery management system, configured to identify the maximum allowable output voltage of the charging pile after the charging circuit is connected to the charging pile. If the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery, otherwise control the charging circuit to perform DC boost charging on the power battery.

6. A vehicle, wherein, it includes the charging system as described in claim 5.

7. A method for charging a power battery using the charging circuit as described in any one of claims 1-4, wherein, the method uses a charging circuit integrated with a DC boost charging component and a DC charging component to perform DC charging or DC boost charging on the power battery. Wherein, the method includes the following steps: After the charging circuit is connected to the charging pile, obtain the maximum allowable output voltage of the charging pile; If the maximum allowable output voltage is greater than the battery voltage of the power battery, control the charging circuit to perform DC charging on the power battery, otherwise control the charging circuit to perform DC boost charging on the power battery.

8. The method for charging a power battery according to claim 7, wherein, the charging circuit further includes an electric drive module. The control of the charging circuit to perform DC boost charging on the power battery includes: After the power battery goes high voltage during DC boost charging, send a voltage transformation demand instruction to the charging pile and a voltage reduction instruction to the electric drive module. Wherein, the electric drive module enters a voltage reduction mode according to the voltage reduction instruction, and reduces the output voltage of the power battery to a voltage matching the voltage of the charging pile; After successfully shaking hands with the charging pile, send a voltage boost instruction to the electric drive module. Wherein, the electric drive module enters a voltage boost mode according to the voltage boost instruction, and performs DC boost charging on the power battery through the electric drive module and the DC boost charging component.

9. The method for charging a power battery according to claim 8, wherein, the DC boost charging component includes a boost relay, a first capacitor and a capacitor relay, and the DC charging component includes a DC relay, a main positive relay and a main negative relay. Wherein, a first sampling point is arranged between the main positive relay and the DC charging port, a second sampling point is arranged between the DC relay and the DC charging port, a third sampling point is arranged between the capacitor relay and the first capacitor, and a fourth sampling point is arranged between the boost relay and the first capacitor.

10. The method for charging a power battery according to claim 9, wherein, after the power battery goes high voltage during DC boost charging, it further includes: obtain the voltages of the first to fourth sampling points; Calculate the first voltage between the third sampling point and the fourth sampling point, the second voltage between the first sampling point and the fourth sampling point, and the third voltage between the first sampling point and the second sampling point according to the voltages of the first to fourth sampling points; When the high voltage of the power battery is activated, the vehicle is not undergoing DC charging, and the closing command of the capacitor relay is not issued, if the first voltage is equal to the second voltage, it is determined that the capacitor relay has an adhesion fault; When the high voltage of the power battery is activated, the vehicle is not undergoing DC charging, the capacitor relay does not have an adhesion fault, and the closing command of the boost relay is not issued, if the first voltage is equal to the third voltage, it is determined that the boost relay has an adhesion fault.

11. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the program is executed by a processor, it is used to implement the charging method of the power battery according to any one of claims 7-10.

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