Battery heating system, control method thereof and vehicle

Abstract

The invention provides a battery heating system, a control method thereof and a vehicle, and relates to the technical field of vehicle control, and the method comprises the following steps: when a power battery has a pulse heating demand, determining a pulse heating mode of the battery heating system according to a connection state of a charging pile; controlling the conduction states of the first switch module, the second switch module and the third switch module to form a pulse charging and discharging loop corresponding to the pulse heating mode; if the mode is the charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery; the duty ratio of the control pulse of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, the pulse charging and discharging loop is controlled to carry out pulse heating on the power battery, the voltage at the two ends of the battery is monitored in real time, the pulse current amplitude is dynamically adjusted, the power battery is protected, the damage risk is reduced, and the service life of the power battery is prolonged. The maximum charging effect can be kept, and the charging rate and the heating rate can be improved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a battery heating system and its control method, and a vehicle. Background Technology

[0002] In low-temperature conditions, the power batteries of new energy vehicles face problems such as difficulty in charging, low discharge efficiency, and reduced cycle life. Typically, the batteries need to be heated before they can be put into operation. Summary of the Invention

[0003] In view of this, this application provides a battery heating system and its control method, as well as a vehicle, which monitors the voltage at both ends of the battery in real time and dynamically adjusts the pulse current amplitude. This protects the power battery from damage and ensures that pulse charging is performed at the maximum pulse current amplitude, thus maintaining the maximum charging effect and improving the charging and heating rates.

[0004] To achieve the above objectives, this application provides the following technical solution: a control method for a battery heating system, the battery heating system comprising: a charging pile, a motor, an inverter, a first switch module, a second switch module, a third switch module, and an energy storage capacitor; the charging pile, the third switch module, the first switch module, and the power battery are connected in sequence, and the power battery, the first switch module, the energy storage capacitor, the inverter, the motor, and the second switch module are connected in sequence; the control method comprises: when the power battery has a pulse heating requirement, determining the pulse heating mode of the battery heating system according to the connection status of the charging pile; controlling the first switch module, the second switch module, and the third switch module. The module's conduction state enables the charging pile, energy storage capacitor, inverter, motor, and power battery to interconnect, forming a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode. If the pulse heating mode is the charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery. In the charging pile pulse heating mode, the charging pile charges and discharges the power battery in a repeated cycle to pulse heat the power battery. The duty cycle of the control pulses of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled according to the duty cycle to pulse heat the power battery.

[0005] In one embodiment of this application, adjusting the target pulse current amplitude according to the current battery voltage of the power battery includes: obtaining the current battery voltage of the power battery; and performing voltage control on a preset maximum battery voltage, maximum battery pulse current, and the current battery voltage to obtain the target pulse current amplitude.

[0006] In one embodiment of this application, the step of voltage control based on a preset maximum battery voltage, a maximum battery pulse current, and the current battery voltage to obtain a target pulse current amplitude includes: comparing the current battery voltage with a preset maximum battery voltage; if the current battery voltage is less than the maximum battery voltage, increasing the current target pulse current amplitude by a preset step size to obtain a first pulse current amplitude; if the current battery voltage is greater than or equal to the maximum battery voltage, decreasing the current target pulse current amplitude by a preset step size to obtain a first pulse current amplitude; and obtaining the target pulse current amplitude based on the first pulse current amplitude and the maximum battery pulse current.

[0007] In one embodiment of this application, obtaining the target pulse current amplitude based on the first pulse current amplitude and the battery's maximum pulse current includes: comparing the first pulse current amplitude with the battery's maximum pulse current; if the first pulse current amplitude is less than the battery's maximum pulse current, then using the first pulse current amplitude as the target pulse current amplitude; if the first pulse current amplitude is greater than or equal to the battery's maximum pulse current, then using the battery's maximum pulse current as the target pulse current amplitude.

[0008] In one embodiment of this application, determining the pulse heating mode of the battery heating system based on the connection status of the charging pile includes: if the charging pile is connected, the pulse heating mode of the power battery is determined to be the charging pile pulse heating mode, wherein the charging pile pulse heating mode is used to charge the power battery through the charging pile during the charging phase and to charge the windings in the motor through the power battery during the discharging phase; if the charging pile is disconnected, the pulse heating mode of the power battery is determined to be the no-charging-pile pulse heating mode, wherein the no-charging-pile pulse heating mode is used to charge the energy storage capacitor through the power battery during the discharging phase and to charge the power battery through the energy storage capacitor during the discharging phase.

[0009] In one embodiment of this application, controlling the conduction states of the first switch module, the second switch module, and the third switch module to interconnect the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode includes: if the pulse heating mode is a charging pile pulse heating mode, controlling the second switch module and the third switch module to close, and the first switch module to open, so that the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery are connected in sequence to form a first pulse charging and discharging heating circuit; if the pulse heating mode is a non-charging pile pulse heating mode, controlling the second switch module to close, and the first switch module and the third switch module to open, so that the power battery, the motor, the inverter, and the energy storage capacitor are connected in sequence to form a second pulse charging and discharging heating circuit.

[0010] In one embodiment of this application, controlling the duty cycle of the control pulses of each phase arm in the inverter according to the target pulse current amplitude and a preset pulse current frequency includes: generating a target pulse current using a square wave generator according to the target pulse current amplitude and the preset pulse current frequency; obtaining a deviation current based on the target pulse current and the actual pulse current; and performing proportional-integral adjustment on the deviation current to obtain the duty cycle of the control pulses of each phase arm in the inverter.

[0011] In one embodiment of this application, obtaining the deviation current based on the target pulse current and the actual pulse current includes: obtaining the phase current of each phase winding of the motor, and calculating the sum of the phase currents of each phase winding to obtain the actual pulse current; calculating the difference between the amplitude of the target pulse current and the actual pulse current to obtain the deviation current.

[0012] As a second aspect of this application, this application also provides a battery heating system, including: a charging pile, a motor, an inverter, a first switch module, a second switch module, a third switch module, and an energy storage capacitor; the charging pile, the third switch module, the first switch module, and the power battery are connected in sequence, and the power battery, the first switch module, the energy storage capacitor, the inverter, the motor, and the second switch module are connected in sequence; the battery heating system further includes a control circuit, the control circuit being used to: determine the pulse heating mode of the battery heating system according to the connection status of the charging pile when the power battery has a pulse heating requirement; and control the first switch module, the second switch module, and the third switch module. The module's conduction state enables the charging pile, motor, inverter, energy storage capacitor, and power battery to interconnect, forming a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode. If the pulse heating mode is the charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery. In the charging pile pulse heating mode, the charging pile charges and discharges the power battery in a repeated cycle to pulse heat the power battery. The duty cycle of the control pulses of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and a preset pulse current frequency, and the pulse charging and discharging circuit is controlled according to the duty cycle to pulse heat the power battery.

[0013] As a third aspect of this application, this application also provides a vehicle including the aforementioned battery heating system.

[0014] This application provides a control method for a battery heating system, the battery heating system comprising: a charging pile, a motor, an inverter, a first switch module, a second switch module, a third switch module, and an energy storage capacitor. The inverter, the first switch module, the second switch module, the third switch module, and the energy storage capacitor are included in a motor controller. The charging pile, the third switch module, the first switch module, and the power battery are connected sequentially, as are the power battery, the first switch module, the energy storage capacitor, the inverter, the motor, and the second switch module. The control method includes: when the power battery requires pulse heating, determining the pulse heating mode of the battery heating system based on the connection status of the charging pile; controlling the conduction status of the first switch module, the second switch module, and the third switch module, so that the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery are interconnected to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode; if the pulse heating mode is... The charging pile pulse heating mode adjusts the target pulse current amplitude according to the current battery voltage of the power battery. This mode involves a repeated cycle of charging and discharging the power battery to pulse heat it. The duty cycle of the control pulses for each phase arm of the inverter is controlled based on the target pulse current amplitude and a preset pulse current frequency. The pulse charging and discharging circuit is then controlled to pulse heat the power battery based on this duty cycle. By monitoring the battery voltage in real time and dynamically adjusting the pulse current amplitude, the system protects the power battery, reducing the risk of damage, while ensuring maximum pulse current amplitude for pulse charging. This maintains maximum charging efficiency and improves both charging and heating rates. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a battery heating system provided in an embodiment of this application.

[0017] Figure 2 This is a flowchart illustrating the control method of the battery heating system provided in an embodiment of this application.

[0018] Figure 3 This is a schematic diagram of another battery heating system provided in an embodiment of this application.

[0019] Figure 4 This is a circuit diagram of a battery heating system provided in an embodiment of this application.

[0020] Figure 5 A schematic diagram of the first pulse charge-discharge heating circuit of the battery heating system provided in the embodiments of this application.

[0021] Figure 6 A schematic diagram of the first pulse charging circuit of the battery heating system provided in the embodiments of this application.

[0022] Figure 7 A schematic diagram of the first pulse discharge circuit of the battery heating system provided in the embodiments of this application.

[0023] Figure 8 A schematic diagram of the second pulse charge-discharge heating circuit of the battery heating system provided in the embodiments of this application.

[0024] Figure 9 A schematic diagram of the equivalent motor drive circuit of the battery heating system provided in the embodiments of this application.

[0025] Figure 10 This is a schematic diagram illustrating the adjustment of the target pulse current amplitude of the battery heating system provided in this application embodiment.

[0026] Figure 11 This is a schematic diagram of pulse current control for a battery heating system provided in an embodiment of this application. Detailed Implementation

[0027] This application provides a battery heating system and its control method, as well as a vehicle. By monitoring the voltage at both ends of the battery in real time and dynamically adjusting the pulse current amplitude, the system can protect the power battery and reduce the risk of damage, while ensuring that pulse charging is performed at the maximum pulse current amplitude. This maintains the maximum charging effect and is beneficial for improving the charging rate and heating rate.

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In low-temperature conditions, new energy vehicles face challenges such as charging difficulties, low discharge efficiency, and reduced cycle life of their power batteries. Typically, the batteries need to be heated before operation. Related technologies often utilize charging stations to charge the power batteries. Without incorporating pulse heating into the battery's operation, pulse heating is achieved through pulsed current flow between the power battery and the energy storage capacitor.

[0030] The technical solutions of this application are applicable to application scenarios involving heating and charging / discharging power batteries in new energy vehicles. Figure 1 The diagram shown is a structural schematic of a battery heating system provided in an embodiment of this application. Figure 1 As shown, the battery heating system includes: a charging pile, a motor 13, an inverter 12, a first switch module 11, a second switch module 14, a third switch module 15, and an energy storage capacitor C1. The inverter 12, the first switch module 11, the second switch module 14, the third switch module 15, and the energy storage capacitor C1 are included in the motor controller 10. The charging pile, the third switch module 15, the first switch module 11, and the power battery are connected in sequence, as are the power battery, the first switch module 11, the energy storage capacitor C1, the inverter 12, the motor 13, and the second switch module 14.

[0031] The battery heating system also includes a control circuit, which is housed in the motor controller. The control circuit is used for: When the power battery requires pulse heating, the pulse heating mode of the battery heating system is determined according to the connection status of the charging pile. Controlling the conduction states of the first switch module, the second switch module, and the third switch module enables the charging pile, the motor, the inverter, the energy storage capacitor, and the power battery to be interconnected to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode; If the pulse heating mode is a charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery. The charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to perform pulse heating on the power battery. The duty cycle of the control pulses of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled to pulse heat the power battery according to the duty cycle.

[0032] The first bus terminal of the inverter 12 is connected to the second terminal of the first switching module 11, and the second bus terminal of the inverter 12 is connected to the negative terminal of the power battery. The first terminal of the motor 13 is connected to the midpoint of the bridge arm of the inverter 12. The first terminal of the second switching module 14 is connected to the positive terminal of the power battery and the first terminal of the first switching module 11, and the second terminal of the second switching module 14 is connected to the second terminal of the motor 13. The first terminal of the energy storage capacitor C1 is connected to the second terminal of the first switching module 11 and the first bus terminal of the inverter 12, and the second terminal of the energy storage capacitor C1 is connected to the second bus terminal of the inverter 12. The first terminal of the third switching module 15 is connected to the second terminal of the first switching module 11 and the first bus terminal of the inverter 12. The first terminal of the charging pile is connected to the second terminal of the third switching module 15, and the second terminal of the charging pile is connected to the negative terminal of the power battery and the second bus terminal of the inverter 12.

[0033] The control circuit controls the different on / off states of the first switch module 11, the second switch module 14, and the third switch module 15, which can form different pulse heating circuits for the power battery. This enables pulse heating of the power battery, improves its heating capacity, provides a fast heating rate, and allows for battery charging at low temperatures.

[0034] In this configuration, the first end of the first phase winding L1 of the motor 13 is connected to the midpoint of the first phase bridge arm in the inverter 12; the first end of the second phase winding L2 of the motor 13 is connected to the midpoint of the second phase bridge arm in the inverter 12; and the first end of the third phase winding L3 of the motor 13 is connected to the midpoint of the third phase bridge arm in the inverter 12. The second ends of the first phase winding L1, the second phase winding L2, and the third phase winding L3 of the motor 13 are connected together to form the neutral point of the motor.

[0035] The first, second, and third phase bridge arms of inverter 12 each include an upper bridge arm and a lower bridge arm. The upper bridge arm of the first phase bridge arm includes a first switch S1 and a diode connected in parallel with the first switch S1. The upper bridge arm of the second phase bridge arm includes a second switch S2 and a diode connected in parallel with the second switch S2. The upper bridge arm of the third phase bridge arm includes a third switch S3 and a diode connected in parallel with the third switch S3. The lower bridge arm of the first phase bridge arm includes a fourth switch S4 and a diode connected in parallel with the fourth switch S4. The lower bridge arm of the second phase bridge arm includes a fifth switch S5 and a diode connected in parallel with the fifth switch S5. The lower bridge arm of the third phase bridge arm includes a sixth switch S6 and a diode connected in parallel with the sixth switch S6. The midpoint of the first phase bridge arm is the intermediate connection point connecting the first switch S1 and the fourth switch S4. The midpoint of the second phase bridge arm is the intermediate connection point connecting the second switch S2 and the fifth switch S5. The midpoint of the third phase bridge arm is the intermediate connection point connecting the third switch S3 and the sixth switch S6.

[0036] The control circuit controls the second switch module 14 and the third switch module 15 to close. The charging pile, the motor, the inverter, the energy storage capacitor, and the power battery are connected in sequence to form a first pulse charging and discharging heating circuit. By controlling the pulse heating mode of the power battery according to the connection status of the charging pile, and adjusting the target pulse current amplitude according to the current battery voltage of the power battery, the duty cycle of each phase bridge arm in the inverter can be accurately adjusted. The pulse current can be adaptively adjusted to maintain the maximum charging effect, which is beneficial to improving the charging rate and heating rate.

[0037] For more specific control methods of the battery heating system, please refer to the control method examples below.

[0038] Based on the above battery heating system, this application provides a control method for the battery heating system, such as... Figure 2 As shown, the control method of the battery heating system includes: Step S11: When the power battery requires pulse heating, the pulse heating mode of the battery heating system is determined according to the connection status of the charging pile.

[0039] The Battery Management System (BMS) of the power battery performs a self-test, acquiring information such as the battery temperature and state of charge (SOC) to determine if the battery requires pulse heating. If the battery temperature is below a temperature threshold and the current SOC is below the SOC threshold, then the battery requires pulse heating; otherwise, the battery does not require pulse heating.

[0040] If the power battery requires pulse heating, the battery management system also determines whether a charging pile is connected and determines the pulse heating mode of the battery heating system based on the connection status of the charging pile. The pulse heating modes of the power battery in the battery heating system include a low-temperature charging pile pulse heating mode and a no-charging-pile pulse heating mode. The battery heating system can be controlled to operate in one of these heating modes by controlling the conduction states of the first, second, and third switch modules.

[0041] Step S12: Control the conduction state of the first switch module, the second switch module and the third switch module to connect the charging pile, the energy storage capacitor, the inverter, the motor and the power battery to form a pulse charging and discharging circuit of the power battery corresponding to the pulse heating mode.

[0042] When the second switch module and the third switch module are turned on, and the first switch module is turned off, the charging pile, the motor, the inverter, the energy storage capacitor and the power battery are connected in sequence to form the first pulse charging and discharging heating circuit.

[0043] When the second switch module is closed and the first switch module and the third switch module are open, the power battery, the motor, the inverter and the energy storage capacitor are connected in sequence to form a second pulse charge and discharge heating circuit.

[0044] When the first switch module is closed and the second and third switch modules are open, the power battery, the energy storage capacitor, the inverter, and the motor are connected in sequence to form a motor drive circuit.

[0045] Step S13: If the pulse heating mode is the charging pile pulse heating mode, adjust the target pulse current amplitude according to the current battery voltage of the power battery, wherein the charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to perform pulse heating on the power battery.

[0046] In this embodiment, when the pulse heating mode is the charging pile pulse heating mode, the charging pile pulse heating mode involves the charging pile repeatedly charging and discharging the power battery to pulse heat the power battery. The current actual battery voltage in the battery heating system circuit cannot exceed the maximum battery voltage of the power battery; otherwise, it may easily cause damage to the components. The current actual battery voltage is the battery voltage that the power battery can output under the charging pile pulse heating mode. Therefore, the pulse current amplitude during battery pulse heating in the battery heating system is related to the current battery voltage, and the target pulse current amplitude can be adjusted according to the current battery voltage.

[0047] Step S14: Control the duty cycle of the control pulse of each phase bridge arm in the inverter according to the target pulse current amplitude and the preset pulse current frequency, and control the pulse charging and discharging circuit to pulse heat the power battery according to the duty cycle.

[0048] The pulse current frequency and target pulse current amplitude are target values, related to the hardware characteristics of the power battery, motor, and motor controller. The pulse current frequency can be obtained by testing the power battery, motor, and motor controller on a test bench. The target pulse current amplitude is obtained through previous adjustments. Different pulse heating modes require different pulse currents for power battery pulse heating. For example, when the battery heating system operates in low-temperature charging pile pulse heating mode, a square wave pulse current is used to pulse heat the power battery. When the battery heating system operates in non-charging pile pulse heating mode, a sinusoidal wave pulse current is used to pulse heat the power battery. A sinusoidal or square wave current is generated based on the preset pulse current frequency and amplitude. The duty cycle of the control pulses in each phase bridge arm of the inverter can be controlled based on the sinusoidal or square wave current, thereby controlling the corresponding pulse charging and discharging circuit to pulse heat the power battery.

[0049] The control method of the battery heating system in this application embodiment determines the pulse heating mode of the battery heating system according to the connection status of the charging pile when the power battery has a pulse heating requirement; controls the conduction state of the first switch module, the second switch module, and the third switch module to interconnect the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to form a pulse charging and discharging circuit of the power battery corresponding to the pulse heating mode; if the pulse heating mode is the charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery, wherein the charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to pulse heat the power battery; the duty cycle of the control pulse of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled according to the duty cycle to pulse heat the power battery. By monitoring the voltage at both ends of the battery in real time and dynamically adjusting the pulse current amplitude, the power battery is protected to reduce the risk of damage, and pulse charging with the maximum pulse current amplitude is ensured to maintain the maximum charging effect, which is beneficial to improving the charging rate and heating rate.

[0050] In the embodiments of this application, see Figure 3The battery heating system also includes a fourth switch module 16. The first terminal of the fourth switch module 16 is connected to the second terminal of the charging pile and the negative terminal of the power battery, and the second terminal of the fourth switch module 16 is connected to the second bus terminal of the inverter 12. Before motor driving and power battery pulse heating, the fourth switch module 16 is also controlled to close to form a circuit.

[0051] The battery heating system in this embodiment can operate in motor drive mode or in power battery pulse heating mode, i.e., pulse heating and charging / discharging of the power battery. Therefore, the operational requirements of the battery heating system need to be determined first. If heating and charging / discharging of the power battery is required, the vehicle needs to be adjusted accordingly to facilitate the battery heating system entering the power battery heating and charging / discharging state.

[0052] Since heating of a power battery is generally achieved through charging and discharging cycles, if the vehicle is connected to a charging station, the charging station can be used for pulse heating of the power battery. Based on this, in this embodiment, optionally, determining the pulse heating mode of the battery heating system based on the connection status of the charging station includes: if the charging station is connected, the pulse heating mode of the power battery is determined to be a charging station pulse heating mode, where the charging phase involves charging the power battery through the charging station, and the discharging phase involves charging the windings in the motor through the power battery; if the charging station is not connected, the pulse heating mode of the power battery is determined to be a no-charging-station pulse heating mode, where the no-charging-station pulse heating mode involves charging the energy storage capacitor through the power battery during the discharging phase, and the discharging phase involves charging the power battery through the energy storage capacitor.

[0053] If the charging pile is connected, the pulse heating mode of the power battery can be determined as the charging pile pulse heating mode, and the charging of the power battery by the connected charging pile can be applied to the pulse heating process of the power battery. In the charging phase, the charging pile charges the power battery through the charging pile; specifically, the charging pile and the energy storage capacitor C1 charge the power battery through Buck discharge. In the discharging phase, the power battery boosts the voltage to charge the energy storage capacitor C1 and the windings in the motor; specifically, the power battery discharges to charge the three-phase inductors of the energy storage capacitor C1 and the motor. These two processes are repeated cyclically to achieve cyclic charging and discharging of the power battery, resulting in battery heating. The charging pile charges the power battery in the form of a square wave current; that is, the target current in the first pulse charging and discharging heating circuit is a square wave. The square wave current has a high effective value, which can improve the battery pack heating rate and shorten the charging time.

[0054] If the charging pile is not connected, the pulse heating mode of the power battery can be defined as a charging pile-less pulse heating mode. This involves cyclically charging and discharging the power battery with the energy storage capacitor, which includes the energy storage capacitor and the three-phase windings of the motor, to achieve pulse heating of the power battery. In the charging pile-less pulse heating mode, during the discharge phase, the power battery charges the energy storage capacitor. Specifically, the power switching transistors in the inverter are controlled to achieve boost discharge of the power battery to charge the energy storage capacitor C1. During the discharge phase, the energy storage capacitor charges the power battery. Specifically, the energy storage capacitor C1 is controlled to buck discharge to charge the power battery. These two processes are repeated cyclically to achieve cyclic charging and discharging of the power battery, resulting in battery heating.

[0055] In the embodiments of this application, considering that the power battery may not have a pulse heating requirement, the battery heating system can operate in other operating modes, such as motor drive mode or normal charging mode of the power battery.

[0056] In this embodiment, the pulse heating command (pulse heating mode, maximum allowable current and frequency, etc.) is determined by the Battery Management System (BMS) based on the battery temperature, SOC, and whether there is a charging pile, etc., and then the signal is sent to the Vehicle Control Unit (VCU). The VCU determines whether the vehicle meets the pulse heating conditions based on the normal speed. If it does, it forwards the signal (including the pulse heating command) to the MCU for control.

[0057] After determining the operating mode of the battery heating system, the first, second, and third switching modules are controlled based on this mode to form a circuit corresponding to the determined operating mode. If the power battery requires heating, the battery heating system is controlled to form a corresponding pulse charge / discharge circuit for the power battery. Based on this, optionally, controlling the conduction state of the first switch module, the second switch module, and the third switch module to interconnect the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode includes: if the pulse heating mode is a charging pile pulse heating mode, controlling the second switch module and the third switch module to close, and the first switch module to open, so that the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery are connected in sequence to form a first pulse charging and discharging heating circuit; if the pulse heating mode is a non-charging pile pulse heating mode, controlling the second switch module to close, and the first switch module and the third switch module to open, so that the power battery, the motor, the inverter, and the energy storage capacitor are connected in sequence to form a second pulse charging and discharging heating circuit.

[0058] In the embodiments of this application, see Figure 4 The third switch module 15 includes a first control switch K1. The first end of the first control switch K1 is connected to the second end of the first switch module 11 and the first bus terminal of the inverter 12. The second end of the first control switch K1 is connected to the first end of the charging pile. After the charging pile is connected, the first control switch K1 can be closed to connect the charging pile to the battery heating system, which can provide pulse charging to the power battery to heat it.

[0059] The third switch module 15 further includes a diode D1; the anode of the diode D1 is connected to the first terminal of the first control switch K1, and the cathode of the diode D1 is connected to the second terminal of the first switch module 11 and the first bus terminal of the inverter 12. Diode D1 is an isolation diode; when the power battery is discharging, diode D1 prevents current from flowing back into the charging pile and causing a charging pile malfunction.

[0060] The first switch module 11 includes a second control switch K2, a third control switch K3, and a first resistor R1. The first terminals of the second control switch K2 and the third control switch K3 are connected to the first terminal of the power battery. The second terminal of the second control switch K2 is connected to the first bus terminal of the inverter 12. The second terminal of the third control switch K3 is connected to the first bus terminal of the inverter 12 through the first resistor R1. The first resistor R1 is a pre-charging resistor. The second control switch K2 and the first resistor R1 form a pre-charging circuit. When the battery heating system is working, the energy storage capacitor C1 is pre-charged to prevent damage to components caused by sudden current changes in the motor drive circuit.

[0061] The second switch module 14 includes a fourth control switch K4, the first terminal of which is connected to the positive terminal of the power battery, the first terminal of the second control switch K2, and the first terminal of the third control switch K3, and the second terminal of which is connected to the neutral point of the motor. The fourth switch module 16 includes a fifth control switch K5, the first terminal of which is connected to the second terminal of the charging pile and the negative terminal of the power battery, and the second terminal of which is connected to the second busbar of the inverter 12.

[0062] If the pulse heating mode is the charging pile pulse heating mode, the second and third switch modules are closed, and the first switch module is opened. That is, the control circuit controls the first control switch K1, the fourth control switch K4, and the fifth control switch K5 to close, and the second control switch K2 and the third control switch K3 to open, so that the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery are connected sequentially to form... Figure 5 The first pulse charge / discharge heating circuit is shown. By controlling the switching transistors in the inverter, the charging pile's buck-boost charging and discharging function can be realized. The target is to control the charging and discharging current of the power battery. When the target current is a square wave (high effective value of the square wave current), it is in pulse charging mode, which can charge at low temperatures. It consists of two processes: the first process involves the charging pile and energy storage capacitor C1 charging the power battery through buck discharge; the second process involves the power battery boosting and discharging to charge the energy storage capacitor C1. These two processes are repeated cyclically to achieve cyclic charging and discharging of the power battery, thereby heating the battery.

[0063] Based on this, the first pulse charge-discharge heating circuit includes a first pulse charging stage where the charging pile charges the power battery and a first pulse discharging stage where the power battery charges at least one phase winding in the motor. When the power battery is in the first pulse charging stage, the charging pile, the energy storage capacitor, the upper arm of at least one phase bridge arm in the inverter corresponding to the at least one phase winding, the at least one phase winding in the motor connected to the upper arm of the at least one phase bridge arm, and the power battery are sequentially connected to form the first pulse charging circuit. For example... Figure 6 The current flows out from the positive terminal of the charging pile, through the energy storage capacitor C1, the first switch S1 of the upper arm of the first phase bridge arm in the inverter, the first phase winding L1, and the power battery, returning to the negative terminal of the charging pile, forming the first pulse charging circuit. It should be noted that the second switch S2 of the upper arm of the second phase bridge arm and / or the third switch S3 of the upper arm of the third phase bridge arm in the inverter 12 can also be controlled to conduct. That is, the charging pile can form the first pulse charging circuit by controlling the upper arm of any one phase bridge arm, any two phase bridge arms, or any three phase bridge arms in the inverter 12 to conduct. The charging pile and the energy storage capacitor C1 charge the power battery through this first pulse charging circuit.

[0064] After the power battery is fully charged, it enters the discharge phase. During the first pulse discharge phase, the power battery, at least one phase winding of the motor, the upper arm of at least one phase bridge arm connected to the at least one phase winding in the inverter, and the energy storage capacitor C1 are sequentially connected to form the first pulse discharge circuit. (See also...) Figure 7The control circuit controls the second switch S2 of the upper arm of the second phase bridge arm to conduct, and the current flows out from the positive terminal of the power battery, passes sequentially through the second phase winding L2, the second switch S2 of the upper arm of the second phase bridge arm, and the energy storage capacitor C1, and returns to the negative terminal of the power battery, forming the first pulse discharge circuit. It should be noted that the first switch S1 of the upper arm of the first phase bridge arm and / or the third switch S3 of the upper arm of the third phase bridge arm in the inverter 12 can also be controlled to conduct. That is, the charging pile can form the first pulse discharge circuit by controlling the upper arm of any one phase bridge arm, any two phase bridge arms, or any three phase bridge arms in the inverter 12 to conduct, and the power battery charges the energy storage capacitor C1 through this first pulse discharge circuit.

[0065] The first pulse charging circuit and the first pulse discharging circuit are cyclically connected to achieve pulse heating of the power battery.

[0066] If the pulse heating mode is a pulse heating mode without a charging pile, the second switch module is closed, and the first and third switch modules are opened. This means the fourth control switch K4 is closed, and the first, second, and third control switches K1, K2, and K3 are opened. Simultaneously, the fifth control switch K5 is closed, connecting the power battery, the motor, the inverter, and the energy storage capacitor in sequence, forming a configuration as shown below. Figure 8 The second pulse charge-discharge heating circuit is shown. This second pulse charge-discharge heating circuit is a Buck / Boost bidirectional buck-boost circuit, which consists of two processes. In the first process, the power switch is controlled to enable the power battery to charge the energy storage capacitor C1 through Boost voltage boosting discharge. After the capacitor voltage increases, the second process is that the energy storage capacitor C1 charges the power battery through Buck voltage bucking discharge. The two processes are repeated cyclically to achieve the cyclic charge-discharge of the power battery, thereby heating the battery.

[0067] The second pulse charge / discharge heating circuit includes a second pulse charging stage and a second pulse discharging stage. When the power battery is in the second pulse discharging stage, the power battery, at least one phase winding of the motor, the upper arm of at least one phase bridge arm in the inverter corresponding to the at least one phase winding, and the energy storage capacitor are connected in series to form a second pulse discharging circuit. It should be noted that multiple phase windings in the motor 13 can be controlled to connect to the second pulse discharging circuit. For example, the upper arms of any two phase bridge arms in the inverter 12 can be controlled to conduct, thereby connecting the two-phase or three-phase windings connected to these two phase bridge arms to the second pulse discharging circuit. The power battery charges the energy storage capacitor C1 through the branch containing the two-phase or three-phase windings. After the power battery completes charging the energy storage capacitor C1, the energy storage capacitor C1 can be controlled to charge the power battery, i.e., the power battery enters the charging stage. When the power battery is in the second pulse charging phase, the energy storage capacitor, the upper arm of at least one phase bridge arm in the inverter, at least one phase winding of the motor connected to the at least one phase bridge arm, the second switching module, and the power battery are connected in series to form a second pulse charging circuit. The second pulse discharging circuit is a Buck step-down circuit. During operation, it controls the transfer of electrical energy stored in the energy storage capacitor C1 to the power battery to charge it. The second pulse discharging circuit and the second pulse charging circuit are cyclically connected to achieve pulse heating of the power battery. At this time, the charging pile is not connected, and the second pulse charging and discharging heating circuit is in a pulse heating mode without a charging pile, and the current is not greater than the discharge current of the power battery.

[0068] Considering that the power battery may not require pulse heating, the battery heating system can operate in other modes, such as motor drive mode or normal charging mode of the power battery. In this embodiment, when the first switch module 11 and the fourth switch module 16 are closed, and the second switch module 14 and the third switch module 15 are open, i.e., the second control switch K2 and the fifth control switch K5 are closed, and the first control switch K1, the third control switch K3, and the fourth control switch K4 are open, the power battery, the first switch module 11, the energy storage capacitor C1, the inverter 12, and the motor 13 form a motor drive circuit. The equivalent circuit of the resulting motor drive circuit is as follows: Figure 9 As shown, the control signal for controlling the motor rotation can be adjusted by regulating the duty cycle of each phase arm of the inverter, thereby adjusting the motor's driving force. The third control switch K3 and the first resistor R1 form a pre-charging circuit, which pre-charges the energy storage capacitor C1 when the battery heating system is operating in other modes, preventing damage to components caused by sudden current changes in the motor drive circuit.

[0069] In this embodiment, the first switch module 11 and the third switch module 15 can be closed, while the second switch module 14 and the fourth switch module 16 can be opened. That is, the first control switch K1 and the second control switch K2 can be closed, while the third control switch K3, the fourth control switch K4 and the fifth control switch K5 can be opened. The charging pile and the power battery form a circuit, so that the charging pile can directly charge the power battery.

[0070] In this embodiment, when the charging pile participates in the pulse heating process of the power battery, the first pulse charge-discharge heating circuit adopts a low-temperature charging pile pulse heating mode. Since the charging current of the charging pile to the power battery is greater than the discharging current of the power battery, pulse heating of the power battery based on the first pulse charge-discharge heating circuit can improve the battery pack heating rate and shorten the charging time. In the first pulse charge-discharge heating circuit, square wave control is used, and the current when the charging pile charges the power battery is greater than the current during the reverse direction, that is, the current in the first pulse charging circuit is greater than the current in the first pulse discharging circuit. This can improve the battery pack heating rate, shorten the charging time, reduce costs, increase efficiency, and enable charging at low temperatures.

[0071] In this embodiment, the battery heating system further includes: a first current sensor A1, a second current sensor A2, and a third current sensor A3; the first current sensor A1 is connected between the midpoint of the first phase winding of the motor and the midpoint of the first phase bridge arm of the inverter 12; the second current sensor A2 is connected between the midpoint of the second phase winding of the motor 13 and the midpoint of the second phase bridge arm of the inverter 12; and the third current sensor A3 is connected between the midpoint of the third phase winding of the motor 13 and the midpoint of the third phase bridge arm of the inverter 12. The first current sensor A1, the second current sensor A2, and the third current sensor A3 are respectively used to detect the current flowing through the first phase winding L1, the second phase winding L2, and the third phase winding L3. Thus, the duty cycle of the control pulse for each phase bridge arm in the inverter can be adjusted according to the detected current, thereby controlling the on and off times of the upper and lower bridge arms in each phase bridge arm based on the duty cycle. This allows for precise control of the current in the first pulse charging and discharging heating circuit, and precise control of the charging and discharging current of the power battery, ensuring a stable charging and discharging current for the power battery.

[0072] Considering the safety of each component in the battery heating system, the target pulse current amplitude must not exceed the pulse current threshold in the power battery. Optionally, adjusting the target pulse current amplitude based on the current battery voltage of the power battery includes: obtaining the current battery voltage of the power battery; and performing voltage control on a preset maximum battery voltage, maximum battery pulse current, and the current battery voltage to obtain the target pulse current amplitude.

[0073] In extremely low temperatures and under low state of charge (SOC) conditions, directly using a charging pile to perform high-current pulse charging and discharging on the power battery poses a risk of damage and lifespan degradation due to the large voltage boost ratio. This application's embodiment first obtains the current battery voltage, specifically using a voltage sensor to detect it. Then, it performs voltage control based on a preset maximum battery voltage, the maximum battery pulse current, and the current battery voltage to obtain a target pulse current amplitude. Specifically, the pulse current amplitude can be adjusted by comparing the current battery voltage with the preset maximum battery voltage, and further adaptively adjusted based on the maximum battery pulse current. This maintains the pulse current at its maximum charging effect, which is beneficial for improving charging and heating rates.

[0074] In this embodiment, the step of voltage control based on a preset maximum battery voltage, maximum battery pulse current, and the current battery voltage to obtain a target pulse current amplitude includes: comparing the current battery voltage with a preset maximum battery voltage; if the current battery voltage is less than the maximum battery voltage, increasing the current target pulse current amplitude by a preset step size to obtain a first pulse current amplitude; if the current battery voltage is greater than or equal to the maximum battery voltage, decreasing the current target pulse current amplitude by a preset step size to obtain a first pulse current amplitude; and obtaining the target pulse current amplitude based on the first pulse current amplitude and the maximum battery pulse current. The preset step size iStep can be set as needed and is not specifically limited here. To ensure the safety of the battery heating system, the actual voltage of the power battery cannot exceed the maximum battery voltage. Therefore, the current battery voltage can be compared with the preset maximum battery voltage. If the current battery voltage is less than the maximum battery voltage, it indicates that the current battery voltage of the power battery has room for increase, and the current target pulse current amplitude can be increased by a preset step size to obtain a first pulse current amplitude. If the current battery voltage is greater than or equal to the battery's maximum voltage, it indicates that the current battery voltage is too high, which could easily damage the components in the battery heating system. The current target pulse current amplitude can be reduced by a preset step size to obtain the first pulse current amplitude. This facilitates the acquisition of the target pulse current amplitude, allowing control of the switching transistors in the inverter based on the pulse current of the power battery's pulse heating, thereby controlling the pulse heating of the power battery.

[0075] The obtained first pulse current amplitude is the pulse current amplitude adjusted according to the maximum battery voltage, and subsequently, based on the adjusted first pulse current amplitude and the maximum pulse current of the battery, the final target pulse current amplitude is determined. Optionally, obtaining the target pulse current amplitude based on the first pulse current amplitude and the maximum pulse current of the battery includes: comparing the first pulse current amplitude with the maximum pulse current of the battery; if the first pulse current amplitude is less than the maximum pulse current of the battery, then using the first pulse current amplitude as the target pulse current amplitude; if the first pulse current amplitude is greater than or equal to the maximum pulse current of the battery, then using the maximum pulse current of the battery as the target pulse current amplitude. Wherein, the maximum pulse current of the battery is the maximum pulse current that the power battery in the battery heating system can withstand. Compare the adjusted first pulse current amplitude with the maximum pulse current of the battery. If the first pulse current amplitude is less than the maximum pulse current of the battery, it indicates that there is room for the pulse current of the power battery to increase, and the first pulse current amplitude can be used as the target pulse current amplitude. If the first pulse current amplitude is greater than or equal to the maximum pulse current of the battery, it indicates that the current battery voltage of the power battery is too high and the battery voltage needs to be reduced, and the maximum pulse current of the battery can be used as the target pulse current amplitude. See Figure 10 , the adjustment of the target pulse current amplitude includes: Step 100: Start.

[0076] Step 101: Initialize iAmp = 0.

[0077] The initial pulse heating current amplitude iAmp is 0.

[0078] Step 102: Determine whether Rx_modPulse == 1. If so, execute 103. If not, return to Step 101.

[0079] Determine whether the pulse heating mode Rx_modPulse is 1. If the pulse heating mode Rx_modPulse is 1, it indicates that the battery heating system is in the charging pile pulse heating mode. If the pulse heating mode Rx_modPulse is not 1, it indicates that the battery heating system is in the non-charging pile pulse heating mode.

[0080] Step 103: Determine whether V1 < Rx_vMaxBatt. If so, execute 104. If not, return to Step 105.

[0081] Wherein, V1 is the current battery voltage, and Rx_vMaxBatt is the maximum battery voltage. Compare the current battery voltage V1 with the maximum battery voltage Rx_vMaxBatt, and then the pulse heating current amplitude iAmp can be adjusted according to the comparison result.

[0082] Step 104: iAmp = iAmp + iStep. Then execute Step 106.

[0083] If the current battery voltage V1 is less than the maximum battery voltage Rx_vMaxBatt, control the current target pulse current amplitude Amp to increase by a preset step iStep.

[0084] Step 105: iAmp = iAmp - iStep. Then execute Step 106.

[0085] If the current battery voltage V1 is greater than or equal to the maximum battery voltage Rx_vMaxBatt, control the current target pulse current amplitude iAmp to decrease by a preset step iStep.

[0086] Step 106: Determine whether iAmp < Rx_iMaxBatt. If so, execute 108. If not, return to Step 107.

[0087] Where Rx_iMaxBatt is the maximum pulse current of the battery. After adjusting the current target pulse current amplitude iAmp, further determine whether the adjusted target pulse current amplitude iAmp is less than the maximum pulse current of the battery Rx_iMaxBatt.

[0088] Step 107: iAmp = Rx_iMaxBatt.

[0089] If the adjusted target pulse current amplitude iAmp is greater than or equal to the maximum pulse current of the battery Rx_iMaxBatt, adjust the final target pulse current amplitude iAmp to the maximum pulse current of the battery Rx_iMaxBatt.

[0090] Step 108: Run one or more pulse cycles and record the maximum voltage uBattCellMax across the battery.

[0091] If the adjusted target pulse current amplitude iAmp is less than the pulse current threshold, run the battery heating system for one or more pulse cycles and record the voltage across the battery at this time, that is, the current battery voltage V1, for the next round of adjustment.

[0092] In this embodiment, after determining the final target pulse current amplitude iAmp, the pulse heating of the power battery can be adjusted according to the target pulse current amplitude and a preset pulse current frequency. Optionally, controlling the duty cycle of the control pulses of each phase arm in the inverter according to the target pulse current amplitude and the preset pulse current frequency includes: generating a target pulse current using a square wave generator based on the target pulse current amplitude and the preset pulse current frequency; obtaining a deviation current based on the target pulse current and the actual pulse current; and performing proportional-integral adjustment on the deviation current to obtain the duty cycle of the control pulses of each phase arm in the inverter. During the pulse heating of the power battery, the actual pulse current should be adjusted to be as close as possible to the target pulse current. A target pulse current can be generated using a square wave generator based on the obtained target pulse current amplitude and a preset pulse current frequency. The deviation current between the target pulse current and the actual pulse current is calculated. Based on this deviation current, proportional-integral-differential (PID) regulation is performed, that is, the deviation current is adjusted proportionally, integrally, and derivatively according to proportional, integral, and derivative coefficients, respectively. This embodiment mainly performs proportional and integral regulation. After PID regulation of the deviation current, the duty cycle of the control pulses for each phase arm of the inverter can be obtained. Subsequently, the conduction state of each switch in the inverter can be adjusted according to the obtained duty cycle, thereby realizing the regulation of the pulse current for pulse heating of the power battery. See also... Figure 11 Under extremely low temperature and low SOC conditions, square wave pulse charging can lead to high battery voltage and potential damage. By acquiring the current battery voltage V1, the target pulse current Ireq is adaptively adjusted based on V1 to ensure the current battery voltage remains within the protection range. The voltage control unit obtains the target pulse current amplitude iAmp based on the current battery voltage V1, the battery's maximum voltage Rx_vMaxBatt, and the battery's maximum pulse current Rx_iMaxBatt. The specific acquisition method is described above and will not be repeated here. Based on the obtained target pulse current amplitude iAmp and the preset pulse current frequency Rx_iFreq, a square wave generator generates the target pulse current Ireq. The formula for the pulse current Ireq generated by the square wave generator is as follows: .

[0093] Where D is the duty cycle, calibrated empirically; T is the pulse period, which is the reciprocal of the pulse current frequency Rx_iFreq; and iBck is the current amplitude when the power battery charges the energy storage capacitor, which is related to the parameters of the motor and the energy storage capacitor. >iBck.

[0094] When Rx_modPulse is 1, it indicates the charging pile pulse heating mode. In this mode, when the charging pile charges the power battery, the battery heating system uses a square wave pulse current. The selector switch selects the target pulse current Ireq generated by the square wave signal generator. The difference between this target pulse current Ireq and the actual pulse current of the battery is calculated to obtain the deviation current. Then, the proportional controller (PI) performs proportional-integral control based on the deviation current to obtain the duty cycle (duty) of the control pulse for each phase arm of the inverter. The actual pulse current of the power battery is the sum of the three-phase current values ​​Iabc. Since the pulse heating current is a square wave pulse at this time, meaning the first pulse charge-discharge heating circuit is in the charging phase of the charging pile charging the power battery, the pulse demand current Ireq generated by the square wave signal generator is not 0. Therefore, the control terminal of the second selector switch is 0, and the second selector switch selects the duty cycle (duty) obtained by the output ratio controller. The hardware system controls each switch of the inverter according to the duty cycle, thereby controlling the pulse heating current of the charging pile charging the power battery.

[0095] It should be noted that during the discharge of the power battery, if it is in the discharge stage of the charging pile pulse heating mode or the non-charging pile pulse heating mode, the pulse heating mode Rx_modPulse is 2, indicating that the pulse current in the battery heating system is a sinusoidal pulse current. When the power battery discharges to the energy storage capacitor C1, the battery heating system uses a sinusoidal pulse current. At this time, a sine wave signal generator is used to generate a target pulse current Ireq based on the preset pulse current frequency Rx_iFreq and pulse current amplitude Rx_iAmp. The specific values ​​of the pulse current frequency Rx_iFreq and pulse current amplitude Rx_iAmp can be obtained through relevant tests on hardware devices such as the battery, motor, and motor controller. At this time, the selector switch selects the target pulse current Ireq generated by the output sine wave signal generator, and the difference is calculated with the actual pulse current of the power battery to obtain the deviation current. Then, the proportional controller performs proportional-integral control based on the deviation current to obtain the duty cycle (duty) of the control pulses of each phase bridge arm in the inverter. The formula for the target pulse current Ireq generated by the sine wave generator is as follows: .

[0096] The hardware system controls the inverter's switching transistors based on the duty cycle, thereby controlling the pulse heating current from the charging pile to charge the power battery. The hardware system is a control model that includes the control logic for the battery, motor, and controller.

[0097] In this embodiment, the actual pulse current is related to the phase current flowing through each phase winding of the motor. Therefore, optionally, obtaining the deviation current based on the target pulse current and the actual pulse current includes: obtaining the phase current of each phase winding of the motor, and calculating the sum of the phase currents of each phase winding to obtain the actual pulse current; calculating the difference between the amplitude of the target pulse current and the actual pulse current to obtain the deviation current. Specifically, a current sensor can be used to detect the phase current flowing through each phase winding of the motor, calculate the sum of the phase currents, and obtain the actual pulse current. It should be noted that when calculating the sum of the phase currents, both amplitude and phase need to be considered simultaneously. Then, the difference between the amplitude of the target pulse current and the actual pulse current is calculated to obtain the deviation current. After PI processing, the deviation current yields the duty cycle of the control pulse for each phase arm of the inverter. Based on this duty cycle, the conduction or judgment of each switching transistor in the three-phase bridge arm of the inverter can be controlled, thereby adjusting the pulse heating of the power battery.

[0098] The control method of the battery heating system in this application embodiment determines the pulse heating mode of the battery heating system according to the connection status of the charging pile when the power battery has a pulse heating requirement; controls the conduction state of the first switch module, the second switch module, and the third switch module to interconnect the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to form a pulse charging and discharging circuit of the power battery corresponding to the pulse heating mode; if the pulse heating mode is the charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery, wherein the charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to pulse heat the power battery; the duty cycle of the control pulse of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled according to the duty cycle to pulse heat the power battery. By monitoring the voltage at both ends of the battery in real time and dynamically adjusting the pulse current amplitude, the power battery is protected to reduce the risk of damage, and pulse charging with the maximum pulse current amplitude is ensured to maintain the maximum charging effect, which is beneficial to improving the charging rate and heating rate.

[0099] This application also provides a vehicle, including the above-described battery heating system.

[0100] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0101] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0102] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0103] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0104] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0105] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A control method for a battery heating system, characterized in that, The battery heating system includes: a charging pile, a motor, an inverter, a first switch module, a second switch module, a third switch module, and an energy storage capacitor; the charging pile, the third switch module, the first switch module, and the power battery are connected in sequence, and the power battery, the first switch module, the energy storage capacitor, the inverter, the motor, and the second switch module are connected in sequence. The control method includes: When the power battery requires pulse heating, the pulse heating mode of the battery heating system is determined according to the connection status of the charging pile. Controlling the conduction states of the first switch module, the second switch module, and the third switch module enables the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to be interconnected to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode; If the pulse heating mode is a charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery. The charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to perform pulse heating on the power battery. The duty cycle of the control pulses of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled to pulse heat the power battery according to the duty cycle.

2. The method according to claim 1, characterized in that, The adjustment of the target pulse current amplitude based on the current battery voltage of the power battery includes: Obtain the current battery voltage of the power battery; The target pulse current amplitude is obtained by voltage control based on the preset maximum battery voltage, maximum battery pulse current, and the current battery voltage.

3. The method according to claim 2, characterized in that, The step of controlling the preset maximum battery voltage, maximum battery pulse current, and current battery voltage to obtain the target pulse current amplitude includes: Compare the current battery voltage with the preset maximum battery voltage; If the current battery voltage is less than the battery's maximum voltage, the current target pulse current amplitude is increased by a preset step size to obtain the first pulse current amplitude. If the current battery voltage is greater than or equal to the battery's maximum voltage, then the current target pulse current amplitude is reduced by a preset step size to obtain the first pulse current amplitude; The target pulse current amplitude is obtained based on the amplitude of the first pulse current and the maximum pulse current of the battery.

4. The method according to claim 3, characterized in that, The step of obtaining the target pulse current amplitude based on the first pulse current amplitude and the battery's maximum pulse current includes: Compare the amplitude of the first pulse current with the maximum pulse current of the battery; If the amplitude of the first pulse current is less than the maximum pulse current of the battery, then the amplitude of the first pulse current is taken as the target pulse current amplitude. If the amplitude of the first pulse current is greater than or equal to the maximum pulse current of the battery, then the maximum pulse current of the battery is used as the target pulse current amplitude.

5. The method according to claim 1, characterized in that, Determining the pulse heating mode of the battery heating system based on the connection status of the charging pile includes: If the charging pile is in a connected state, the pulse heating mode of the power battery is determined to be the charging pile pulse heating mode. The charging pile pulse heating mode is used to charge the power battery through the charging pile during the charging phase and to charge the windings in the motor through the power battery during the discharging phase. If the charging pile is not connected, the pulse heating mode of the power battery is determined to be the no-charging-pile pulse heating mode. In the no-charging-pile pulse heating mode, the power battery charges the energy storage capacitor through the discharge phase, and the energy storage capacitor charges the power battery through the discharge phase.

6. The method according to claim 1, characterized in that, The control of the conduction states of the first switch module, the second switch module, and the third switch module, enabling the charging pile, the energy storage capacitor, the inverter, the motor, and the power battery to interconnect and form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode, includes: If the pulse heating mode is the charging pile pulse heating mode, the second switch module and the third switch module are closed, and the first switch module is opened, so that the charging pile, the energy storage capacitor, the inverter, the motor and the power battery are connected in sequence to form the first pulse charging and discharging heating circuit; If the pulse heating mode is a pulse heating mode without a charging pile, the second switch module is closed, and the first switch module and the third switch module are opened, so that the power battery, the motor, the inverter and the energy storage capacitor are connected in sequence to form a second pulse charging and discharging heating circuit.

7. The method according to claim 1, characterized in that, The step of controlling the duty cycle of the control pulses of each phase arm in the inverter according to the target pulse current amplitude and the preset pulse current frequency includes: A square wave generator is used to generate the target pulse current based on the target pulse current amplitude and the preset pulse current frequency. The deviation current is obtained based on the target pulse current and the actual pulse current; The deviation current is adjusted proportionally and integrally to obtain the duty cycle of the control pulse for each phase arm of the inverter.

8. The method according to claim 7, characterized in that, The step of obtaining the deviation current based on the target pulse current and the actual pulse current includes: Obtain the phase current of each phase winding of the motor, and calculate the sum of the phase currents of each phase winding to obtain the actual pulse current; The difference between the target pulse current amplitude and the actual pulse current is calculated to obtain the deviation current.

9. A battery heating system, characterized in that, The battery heating system includes: a charging pile, a motor, an inverter, a first switch module, a second switch module, a third switch module, and an energy storage capacitor; the charging pile, the third switch module, the first switch module, and the power battery are connected in sequence, and the power battery, the first switch module, the energy storage capacitor, the inverter, the motor, and the second switch module are connected in sequence. The battery heating system further includes a control circuit, which is used for: When the power battery requires pulse heating, the pulse heating mode of the battery heating system is determined according to the connection status of the charging pile. Controlling the conduction states of the first switch module, the second switch module, and the third switch module enables the charging pile, the motor, the inverter, the energy storage capacitor, and the power battery to be interconnected to form a pulse charging and discharging circuit for the power battery corresponding to the pulse heating mode; If the pulse heating mode is a charging pile pulse heating mode, the target pulse current amplitude is adjusted according to the current battery voltage of the power battery. The charging pile pulse heating mode is a cycle of charging the power battery and discharging the power battery to perform pulse heating on the power battery. The duty cycle of the control pulses of each phase bridge arm in the inverter is controlled according to the target pulse current amplitude and the preset pulse current frequency, and the pulse charging and discharging circuit is controlled to pulse heat the power battery according to the duty cycle.

10. A vehicle, characterized in that, The vehicle includes: the battery heating system as described in claim 9.

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