Battery self-heating device and method, and vehicle

Abstract

A battery self-heating device includes a bridge arm converter (3), an energy storage element (5), an inductor (4), and a controller. The controller is configured to control the connection and disconnection of the bridge arm converter (3) so that in a preset state, the first power battery (1) and the second power battery (2) are respectively charged / discharged by the inductor (4), each forming a free-wheeling circuit with the energy storage element (5) to realize continuous heating of the first power battery (1) and the second power battery (2). Further, a self-heating method performed by the device and a vehicle having the device are disclosed. Two power batteries are provided, and a free-wheeling energy storage element (5) is provided so that an oscillating current can be generated between each of the two power batteries and the inductor (4) to realize low-cost and highly efficient battery self-heating, which can also ensure the stability of the total voltage of the two power batteries and the continuous flow of current in the battery, thereby ensuring the safety of the battery during the self-heating process.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of Chinese Patent Application No. 202210474898.0, entitled "BATTERY SELF-HEATING DEVICE AND METHOD, AND VEHICLE," filed on April 29, 2022. The entire contents of the above application are incorporated herein by reference.

[0002] The present disclosure relates to the technical field of batteries, and more particularly to battery self-heating devices and methods, and vehicles. [Background technology]

[0003] In low temperature environment, the temperature of the lithium-ion power battery of the pure electric vehicle is too low. The activity of the positive electrode material, negative electrode material and electrolyte of the battery decreases, and the internal resistance of the battery increases with the decrease in temperature, so that in low temperature environment, the charge and discharge performance of the pure electric vehicle is significantly reduced. Therefore, the power battery of the pure electric vehicle must be heated to increase the temperature of the body of the power battery and ensure the normal use of the pure electric vehicle under low temperature conditions.

[0004] Existing methods for heating the power battery of an electric vehicle mainly include external heating and internal heating. External heating involves adding additional heating equipment to heat the battery, but water channels, air channels, pipelines, low-pressure systems, etc. need to be allocated, resulting in an increase in overall costs. Due to the long water channels and pipelines, the heat loss is significant and the heating time is slow and long. The principle of internal heating is mainly that the battery is cyclically charged and discharged, and heat is generated depending on the internal resistance of the battery. However, in the battery self-heating technology that can be realized at present, the heating power is limited, and the charging and discharging of the battery pack are performed alternately, which causes voltage fluctuations (ripples) across the battery pack. Summary of the Invention [Means for solving the problem]

[0005] The purpose of the present disclosure is to provide a battery self-heating device and method, and a vehicle. Two power batteries are provided, and a circulating energy storage element is provided between each of the two power batteries and an inductor to generate an oscillating current, in order to realize low-cost and highly efficient battery self-heating, which can also ensure the stability of the total voltage of the two power batteries and the continuous flow of current in the battery, thereby ensuring the safety of the battery during the self-heating process.

[0006] In order to achieve the above-mentioned object, the present disclosure provides a battery self-heating device. The device includes a bridge arm converter, an energy storage element, an inductor, and a controller. A first bus terminal of the bridge arm converter is connected to the positive pole of the first power battery, and a second bus terminal of the bridge arm converter is connected to the negative pole of the second power battery. A first end of the inductor is connected to the midpoint of the bridge arm converter, and a second end of the inductor is connected to the negative pole of the first power battery and the positive pole of the second power battery. An energy storage element is connected in parallel between the positive pole of the first power battery and the negative pole of the second power battery, and a first end of the energy storage element is connected to the first bus terminal of the bridge arm converter, and a second end of the energy storage element is connected to the second bus terminal of the bridge arm converter. The controller is configured to control the connection and disconnection of the bridge arm converter to enable the first power battery and the second power battery to be charged / discharged by the inductor, respectively, in a preset state, and to form a free-wheeling circuit with the energy storage element, respectively, to realize continuous heating of the first power battery and the second power battery.

[0007] Optionally, when one of the first power battery and the second power battery is charged / discharged by the inductor, the other of the first power battery and the second power battery forms a free-wheeling circuit with the energy storage element.

[0008] Optionally, a current flow direction when one of the first power battery and the second power battery is charged / discharged by the inductor is a first direction, and a circulation current flow direction of the other of the first power battery and the second power battery is a second direction, the first direction being opposite to the second direction.

[0009] Optionally, the controller is configured to control alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter to enable the first power battery and the second power battery to be charged / discharged, respectively, by the inductor in a preset state, and to form a free-wheeling circuit with the energy storage element, respectively, to realize continuous heating of the first power battery and the second power battery.

[0010] Optionally, the controller is configured to control, in a preset state, the alternating connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter according to a preset duty cycle allocation setting.

[0011] Optionally, the controller is configured to control, in the preset state, when the upper bridge arm of the bridge arm converter is in a connected state, the lower bridge arm of the bridge arm converter is in a disconnected state, and the upper bridge arm of the bridge arm converter is a duration that reaches a first preset duration in the preset duty cycle allocation setting, to control the upper bridge arm of the bridge arm converter to be disconnected and the lower bridge arm of the bridge arm converter to be connected, and to control the upper bridge arm of the bridge arm converter to be connected and the lower bridge arm of the bridge arm converter to be disconnected, when the lower bridge arm of the bridge arm converter is in a connected state, the upper bridge arm of the bridge arm converter is in a disconnected state, and the lower bridge arm of the bridge arm converter is a duration that reaches a second preset duration in the preset duty cycle allocation setting.

[0012] Optionally, when the upper bridge arm of the bridge arm converter is in a connected state, the inductor is switched from discharging energy to the first power battery to receiving energy from the first power battery and the energy storage element, and the energy storage element is switched from receiving energy from the first power battery and the second power battery to discharging energy to the second power battery and the inductor, depending on the connection time of the upper bridge arm of the bridge arm converter; and when the lower bridge arm of the bridge arm converter is in a connected state, the inductor is switched from discharging energy to the second power battery to receiving energy from the second power battery and the energy storage element, and the energy storage element is switched from receiving energy from the first power battery and the second power battery to discharging energy to the first power battery and the inductor, depending on the connection time of the lower bridge arm of the bridge arm converter.

[0013] Optionally, a first duration during which the inductor receives energy from the first power battery and the energy storage element is longer than a second duration during which the inductor releases energy to the second power battery, and a third duration during which the inductor receives energy from the second power battery and the energy storage element is longer than a fourth duration during which the inductor releases energy to the first power battery.

[0014] Optionally, the controller is configured to obtain a current value of the inductor and / or a voltage value across the inductor in a preset state, and control the alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter according to the current value and / or the voltage value.

[0015] Optionally, the inductor is an inductor in a drive motor of the vehicle.

[0016] Optionally, the energy storage element comprises a capacitor.

[0017] Optionally, the bridge arm converter is a three-phase converter and includes three phase bridge arms.

[0018] The present disclosure further provides a battery self-heating method. The method includes controlling the connection and disconnection of a bridge arm converter to allow the first power battery and the second power battery to be respectively charged / discharged by an inductor in a preset state, and respectively form a free-wheeling circuit by an energy storage element to realize continuous heating of the first power battery and the second power battery. A first bus terminal of the bridge arm converter is connected to the positive pole of the first power battery, and a second bus terminal of the bridge arm converter is connected to the negative pole of the second power battery. A first end of the inductor is connected to the midpoint of the bridge arm converter, and a second end of the inductor is connected to the negative pole of the first power battery and the positive pole of the second power battery. An energy storage element is connected in parallel between the positive pole of the first power battery and the negative pole of the second power battery, and a first end of the energy storage element is connected to the first bus terminal of the bridge arm converter, and a second end of the energy storage element is connected to the second bus terminal of the bridge arm converter.

[0019] The present disclosure further provides a vehicle, the vehicle including the battery self-heating device described above.

[0020] Through the above technical solution, a battery self-heating device is provided that uses an energy storage element to provide a free-wheeling capacity. Two power batteries are provided, and a free-wheeling energy storage element is provided that generates an oscillating current between each of the two power batteries and an inductor, in order to realize low-cost and highly efficient battery self-heating, and the stability of the total voltage of the two power batteries and the continuous flow of current in the battery can also be guaranteed, thereby ensuring the safety of the battery during the self-heating process.

[0021] Other features and advantages of the present disclosure are described in the following detailed description.

[0022] The accompanying drawings are used to provide a further understanding of the present disclosure, constitute a part of this specification, and are used to explain the present disclosure together with the following specific embodiments and do not constitute limitations thereto. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a structural block diagram of a battery self-heating device according to an exemplary embodiment of the present disclosure. [Diagram 2] FIG. 13 is a structural block diagram of a battery self-heating device according to another exemplary embodiment of the present disclosure. [Diagram 3] FIG. 13 is a structural block diagram of a battery self-heating device according to another exemplary embodiment of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a first stage oscillatory current flow direction during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Diagram 5] FIG. 1 is a schematic diagram of the flow direction of the first stage of reflux current during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 6] FIG. 13 is a schematic diagram of a second stage oscillatory current flow direction within a current cycle period in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 7] FIG. 13 is a schematic diagram of the flow direction of the second stage of the return current during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 8] FIG. 13 is a schematic diagram of a third stage oscillatory current flow direction during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 9] FIG. 13 is a schematic diagram of the flow direction of the return current during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 10] FIG. 13 is a schematic diagram of a fourth stage of oscillatory current flow direction during a current cycle in a battery self-heating process according to an exemplary embodiment of the present disclosure. [Figure 11] FIG. 13 is a schematic diagram of the flow direction of the return current during a current cycle in a battery self-heating process in accordance with an exemplary embodiment of the present disclosure. [Figure 12] 4 is a flow chart of a battery self-heating method according to an exemplary embodiment of the present disclosure. [Explanation of symbols]

[0024] 1. First Power Battery 2 Second Power Battery 3 Bridge Arm Converter 4 Inductors 5 Energy storage element DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to describe and explain the present disclosure, and are not used to limit the present disclosure.

[0026] It should be noted that all actions to obtain signals, information, or data in this disclosure are performed subject to compliance with the corresponding data protection regulations and policies of the country in which the signals, information, or data are located, and are performed where authorization is granted by the corresponding device owner.

[0027] FIG. 1 is a structural block diagram of a battery self-heating device according to an exemplary embodiment of the present disclosure. As shown in FIG. 1, the device includes a bridge arm converter 3, an energy storage element 5, an inductor 4, and a controller (not shown). A first bus terminal of the bridge arm converter 3 is connected to the positive pole of the first power battery 1, and a second bus terminal of the bridge arm converter 3 is connected to the negative pole of the second power battery 2. A first end of the inductor 4 is connected to the midpoint of the bridge arm converter 3, and a second end of the inductor 4 is connected to the negative pole of the first power battery 1 and the positive pole of the second power battery 2. An energy storage element 5 is connected in parallel between the positive pole of the first power battery 1 and the negative pole of the second power battery 2, and a first end of the energy storage element 5 is connected to the first bus terminal of the bridge arm converter 3, and a second end of the energy storage element 5 is connected to the second bus terminal of the bridge arm converter 3. The controller is configured to control the connection and disconnection of the bridge arm converter 3 so as to enable the first power battery 1 and the second power battery 2 to be charged / discharged, respectively, by the inductor 4 in a preset state, and to form a free-wheeling circuit with the energy storage element 5, respectively, to realize continuous heating of the first power battery 1 and the second power battery 2.

[0028] The first power battery 1 and the second power battery 2 may be power batteries in the same vehicle. The first power battery 1 and the second power battery 2 may be two power batteries arranged separately, or may be two parts of a power battery obtained by dividing the original power battery in the vehicle. For example, a midpoint of the original power battery in the vehicle may be drawn to divide the power battery in the vehicle into the first power battery 1 and the second power battery 2. The bridge arm converter 3 may be a bridge arm converter 3 in a motor controller in the vehicle. The inductor 4 may be an inductor 4 in a motor controlled by the motor controller in the vehicle. The controller may be any form of controller, which may be a separately arranged controller, or may be a control module integrated in a vehicle control unit (VCU) or the like.

[0029] The preset state may be a state in which the first power battery 1 and the second power battery 2 need to be heated, for example, the electrical quantity of the first power battery 1 and the second power battery 2 is lower than a preset electrical quantity threshold, or the temperature of the first power battery 1 and the second power battery 2 is lower than a preset temperature threshold.

[0030] The controller controls the connection and disconnection of the bridge arm converter 3 in a preset state, so that an oscillating current is generated by each of the first power battery 1 and the second power battery 2 by the inductor 4, and the first power battery 1 and the second power battery 2 are respectively charged / discharged by the inductor 4, to realize the heating of the first power battery 1 and the second power battery 2. In this way, the self-heating of the power battery can be realized without providing additional heating equipment, and the first power battery 1 and the second power battery 2 can be charged and discharged by generating an oscillating current by the inductor 4, respectively, that is, when the first power battery 1 is discharged, the second power battery 2 is charged, and when the second power battery 2 is discharged, the first power battery 1 is charged. Therefore, it can be ensured that the total voltage of the first power battery 1 and the second power battery 2 is relatively stable and unchanged, so that the battery ripple in the battery self-heating process can be reduced, and the electrical safety in the vehicle can be guaranteed.

[0031] In addition, the energy storage element 5 is connected in parallel between the first power battery 1 and the second power battery 2, so that when the first power battery 1 is charged / discharged and the second power battery 2 is charged / discharged, and the heating of the first power battery 1 and the second power battery 2 continues, the current of the first power battery 1 and the second power battery 2 is not interrupted, thereby further ensuring the self-heating efficiency of the batteries and preventing harmonic hazards due to current interruption of the batteries.

[0032] Through the above technical solution, a battery self-heating device is provided that uses an energy storage element to provide a free-wheeling capacity. Two power batteries are provided, and a free-wheeling energy storage element is provided that generates an oscillating current between each of the two power batteries and an inductor, in order to realize low-cost and highly efficient battery self-heating, and the stability of the total voltage of the two power batteries and the continuous flow of current in the battery can also be guaranteed, thereby ensuring the safety of the battery during the self-heating process.

[0033] In a possible embodiment, the bridge arm converter 3 may include a single-phase bridge arm or a multi-phase bridge arm. In the present disclosure, the number of phases of the bridge arm converter 3 is not limited and may be specifically determined according to the bridge arm converter actually applied to the motor controller of the vehicle. There may be one or more inductors 4, which may be specifically determined according to the number of phases of the bridge arm converter 3. For example, as specifically shown in FIG. 2, the bridge arm converter 3 may include a three-phase bridge arm, and there may be three inductors 4, and FIG. 2 shows a schematic diagram of a battery self-heating device including a converter including three-phase bridge arms and three inductors 4 corresponding to the three-phase bridge arms. The first ends of the inductors 4 are respectively connected to the midpoints of the three-phase bridge arms. The second ends of the inductors 4 are connected to the negative pole of the first power battery 1 and the positive pole of the second power battery 2 after being connected to each other.

[0034] In a general circuit including a motor, the currents flowing through the inductor 4 in the motor have different directions at any time to ensure that the total current entering the neutral point of the motor is equal to the total current flowing out of the neutral point of the motor, for example, 1 phase in and 1 phase out, or 1 phase in and 2 phase out, or 1 phase out and 2 phase inlet. Therefore, the maximum current flowing through a conventional motor can only be the limited current of the 1-phase inductor 4. However, in the schematic diagram of the battery self-heating device according to the present disclosure shown in FIG. 2, when the bridge arm converter 3 includes a 3-phase bridge arm and three inductors 4 respectively connected to the three midpoints of the 3-phase bridge arms, the inductor 4 can be drawn through the second end of the inductor 4 connected to the negative pole of the first power battery 1 and the positive pole of the second power battery 2, so that the currents of the three phases in the inductor 4 can be in the same direction. Therefore, the magnitude of the current that can flow through the inductor 4 is greatly increased, and the maximum current-carrying capacity of the motor in which the inductor 4 is located can be fully exerted. The higher the current, the more heat is generated in the first power battery 1 and the second power battery 2, so that the battery self-heating efficiency realized by this embodiment can be further improved.

[0035] Besides, as shown in Fig. 2, in a battery self-heating device in which the bridge arm converter 3 includes three-phase bridge arms and three inductors 4 respectively connected to the midpoints of the three-phase bridge arms, when the currents in the three inductors 4 are the same, the magnitudes of the currents in the three inductors 4 are equal. The real-time electromagnetic forces synthesized in the motor where the inductors 4 are located are zero, thereby realizing zero torque output and ensuring that the motor remains stationary in the self-heating process without any additional torque control.

[0036] In a possible embodiment, as shown in FIG. 3, the energy storage element 5 can be a capacitor.

[0037] In a possible embodiment, when one of the first power battery 1 and the second power battery 2 (as shown in Figures 4, 6, 8, and 10) is charged / discharged by the inductor 4, the other of the first power battery 1 and the second power battery 2 (as shown in Figures 5, 7, 9, and 11) forms a free-wheeling circuit with the energy storage element 5 (it should be understood by those skilled in the art that the free-wheeling circuit may further include other elements, such as the inductor 4 in Figure 5 and another power battery in Figure 7, but this will not be repeated here).

[0038] Furthermore, the direction of current flow when one of the first power battery 1 and the second power battery 2 is charged / discharged by the inductor 4 is a first direction (as shown in Figures 4, 6, 8, and 10), and the direction of circulation current flow of the other of the first power battery 1 and the second power battery 2 is a second direction (as shown in Figures 5, 7, 9, and 11), where the first direction is opposite to the second direction.

[0039] In a possible embodiment, the controller is configured to control the alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3, so as to enable the first power battery 1 and the second power battery 2 to be respectively charged / discharged by the inductor 4 in a preset state, and respectively form a free-wheeling circuit with the energy storage element 5 to realize continuous heating of the first power battery 1 and the second power battery 2. A specific alternate connection and disconnection scheme may be shown in Figures 4 to 11. The reference numbers of various devices are not shown in Figures 4 to 11, and reference numbers of various devices in Figures 1 to 3 may be referred to.

[0040] 4-11 are schematic diagrams of current flow directions for four stages during a current cycle in a battery self-heating process, respectively, according to an exemplary embodiment of the present disclosure.

[0041] First stage: the upper bridge arm of the bridge arm converter 3 is controlled to be connected, the lower bridge arm is controlled to be disconnected, the first power battery 1 is discharged, the energy storage element 5 is discharged, the second power battery 2 is charged, and the inductor 4 is charged. The flow direction of the oscillation current to make the battery self-heat is shown in FIG. 4. The current flows out from the positive pole of the first power battery 1, flows through the upper bridge arm and inductor 4 of the bridge arm converter 3, and returns to the negative pole of the first power battery 1. The first power battery 1 discharges to the inductor 4. The flow direction of the circulating current is shown in FIG. 5. The current flows out from the positive pole of the energy storage element 5, flows through the upper bridge arm of the bridge arm converter 3, the inductor 4, and the second power battery 2, and returns to the negative pole of the energy storage element 5. The second power battery 2 is charged.

[0042] It should be noted that the discharge process shown in FIG. 4 and the freewheeling current charging process shown in FIG. 5 are performed simultaneously. Therefore, in the first stage, there is a current flowing through the first power battery 1 and the second power battery 2 simultaneously, and simultaneous self-heating is realized. Besides, the current directions of the first power battery 1 and the second power battery 2 are opposite. The changes in the terminal voltages of the first power battery 1 and the second power battery 2 may cancel each other out. The overall terminal voltage fluctuation of the battery pack is small, and the ripple of the battery pack can be reduced.

[0043] Second stage: the upper bridge arm of the bridge arm converter 3 is controlled to be disconnected, and the lower bridge arm is controlled to be connected, the first power battery 1 is discharged, the inductor 4 is discharged, the second power battery 2 is charged, and the energy storage element 5 is charged. The flow direction of the oscillating current for self-heating the battery is shown in FIG. 6. The current flows out of the inductor 4 to the positive pole of the second power battery 2, flows out of the negative pole of the second power battery 2, flows through the lower bridge arm of the bridge arm converter 3, and returns to the inductor 4. The second power battery 2 is charged by the inductor 4. The flow direction of the circulating current is shown in FIG. 7. The first power battery 1 is connected in series with the second power battery 2. The current flows out of the positive pole of the first power battery 1, flows through the energy storage element 5, and returns to the negative pole of the second power battery 2. The first power battery 1 and the second power battery 2 both discharge to the energy storage element 5.

[0044] It should be noted that the charging process shown in FIG. 6 and the circulating current discharging process shown in FIG. 7 are performed simultaneously. Therefore, in the first stage, there is a current flowing through the first power battery 1 and the second power battery 2 simultaneously, and simultaneous self-heating is realized. Besides, the current directions of the first power battery 1 and the second power battery 2 are opposite. The changes in the terminal voltages of the first power battery 1 and the second power battery 2 may cancel each other out. The overall terminal voltage fluctuation of the battery pack is small, and the ripple of the battery pack can be reduced.

[0045] Third stage: the upper bridge arm of the bridge arm converter 3 is left disconnected and the lower bridge arm is connected. The first power battery 1 is charged, the inductor 4 is charged, the second power battery 2 is discharged, and the energy storage element 5 is discharged. The flow direction of the oscillating current for self-heating the battery is shown in FIG. 8. The current flows out of the positive pole of the second power battery 2, through the inductor 4 and the lower bridge arm of the bridge arm converter 3, and back to the second power battery 2. The second power battery 2 discharges to the inductor 4. The flow direction of the circulating current is shown in FIG. 9. The current flows out of the positive pole of the energy storage element 5, through the first power battery 1, the inductor 4, and the lower bridge arm of the bridge arm converter 3, and back to the negative pole of the energy storage element 5. The first power battery 1 is charged.

[0046] It should be noted that the discharge process shown in FIG. 8 and the freewheeling current charging process shown in FIG. 9 are performed simultaneously. Therefore, in the first stage, there is a current flowing through the first power battery 1 and the second power battery 2 simultaneously, and simultaneous self-heating is realized. Besides, the current directions of the first power battery 1 and the second power battery 2 are opposite. The changes in the terminal voltages of the first power battery 1 and the second power battery 2 may cancel each other out. The overall terminal voltage fluctuation of the battery pack is small, and the ripple of the battery pack can be reduced.

[0047] Fourth stage: the upper bridge arm of the bridge arm converter 3 is controlled to be connected, and the lower bridge arm is controlled to be disconnected. The first power battery 1 is charged, the energy storage element 5 is charged, the second power battery 2 is discharged, and the inductor 4 is discharged. The flow direction of the oscillating current for self-heating the battery is shown in FIG. 10. The current flows out of the inductor 4, through the upper bridge arm of the bridge arm converter 3, into the positive pole of the first power battery 1, out of the negative pole of the first power battery 1, and back to the inductor 4. The first power battery 1 is charged by the inductor 4. The flow direction of the circulating current is shown in FIG. 11. The first power battery 1 is connected in series with the second power battery 2. The current flows out of the positive pole of the first power battery 1, through the energy storage element 5, and back to the negative pole of the second power battery 2. The first power battery 1 and the second power battery 2 both discharge to the energy storage element 5.

[0048] It should be noted that the charging process shown in FIG. 10 and the circulating current discharging process shown in FIG. 11 are performed simultaneously. Therefore, in the first stage, there is a current flowing through the first power battery 1 and the second power battery 2 simultaneously, and simultaneous self-heating is realized. Besides, the current directions of the first power battery 1 and the second power battery 2 are opposite. The changes in the terminal voltages of the first power battery 1 and the second power battery 2 may cancel each other out. The overall terminal voltage fluctuation of the battery pack is small, and the ripple of the battery pack can be reduced.

[0049] In a possible embodiment, the controller is configured to control, in a preset state, the alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3 according to a preset duty cycle allocation setting. Thus, the controller can accurately determine and accurately control the time of switching the connection and disconnection states of the upper bridge arm and the lower bridge arm according to the preset duty cycle allocation setting to switch from the stage shown in Figures 4 and 5 to the stage shown in Figures 6 and 7, and from the stage shown in Figures 8 and 9 to the stage shown in Figures 10 and 11.

[0050] Specifically, the upper bridge arm and the lower bridge arm of the bridge arm converter 3 are controlled to be alternately connected and disconnected according to the preset duty cycle allocation setting. As an example, the controller may be configured to control the upper bridge arm of the bridge arm converter 3 to be disconnected and the lower bridge arm of the bridge arm converter 3 to be connected when, in the preset state, the upper bridge arm of the bridge arm converter 3 is in a connected state, the lower bridge arm of the bridge arm converter 3 is in a disconnected state, and the duration of the upper bridge arm of the bridge arm converter 3 in a connected state is a duration that reaches a first preset duration in the preset duty cycle allocation setting. For example, the stages shown in Figures 4 and 5 are switched to the stages shown in Figures 6 and 7. When the lower bridge arm of the bridge arm converter 3 is in a connected state, the upper bridge arm of the bridge arm converter 3 is in a disconnected state, and the duration of the lower bridge arm of the bridge arm converter 3 is a duration that reaches a second preset duration in the preset duty cycle allocation setting, the upper bridge arm of the bridge arm converter 3 is controlled to be connected and the lower bridge arm of the bridge arm converter 3 is controlled to be disconnected. For example, the stages shown in FIGS. 8 and 9 are switched to the stages shown in FIGS.

[0051] Both the first preset duration and the second preset duration in the preset duty cycle allocation setting may be determined empirical data, may be pre-calibrated according to experimental data, or may be determined according to a formula. The formula may characterize the correspondence between various thresholds and environmental information. When the environmental information changes, the various thresholds may change accordingly. The environmental information may include, for example, battery usage duration, state of charge (SOC) information, battery temperature, and ambient temperature.

[0052] In addition, when the upper bridge arm of the bridge arm converter 3 is in a connected state, the inductor 4 is switched from discharging energy to the first power battery 1 to receiving energy from the first power battery 1 and the energy storage element 5, and the energy storage element 5 is switched from receiving energy from the first power battery 1 and the second power battery 2 to discharging energy to the second power battery 2 and the inductor 4, depending on the connection time of the upper bridge arm of the bridge arm converter 3. For example, the stages shown in Figures 10 and 11 are switched to the stages shown in Figures 4 and 5.

[0053] When the lower bridge arm of the bridge arm converter 3 is in a connected state, depending on the connection time of the lower bridge arm of the bridge arm converter 3, the inductor 4 is switched from discharging energy to the second power battery 2 to receiving energy from the second power battery 2 and the energy storage element 5, and the energy storage element 5 is switched from receiving energy from the first power battery 1 and the second power battery 2 to discharging energy to the first power battery 1 and the inductor 4. For example, the stages shown in Figures 6 and 7 are switched to the stages shown in Figures 8 and 9.

[0054] Moreover, to ensure a continuous flow of the circulating current, the first duration during which the inductor 4 receives the energy of the first power battery 1 and the energy storage element 5 is longer than the second duration during which the inductor 4 releases energy to the second power battery 2 when the preset duty cycle allocation setting is determined. For example, the duration of the phase shown in Figs. 4 and 5 is longer than the duration of the phase shown in Figs. 6 and 7. It is ensured that the third duration during which the inductor 4 receives the energy of the second power battery 2 and the energy storage element 5 is longer than the fourth duration during which the inductor 4 releases energy to the first power battery 1. For example, the duration of the phase shown in Figs. 8 and 9 is longer than the duration of the phase shown in Figs. 10 and 11.

[0055] In a possible embodiment, the controller is further configured to obtain a current value of the inductor 4 and / or a voltage value across the inductor 4 in a preset state, and control the alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3 according to the current value and / or the voltage value. The threshold values ​​of the current value and / or the voltage value may alternatively be determined according to empirical data or may be pre-calibrated according to experimental data.

[0056] 12 is a flowchart of a battery self-heating method according to an exemplary embodiment of the present disclosure. As shown in FIG. 12, the method may include step 101.

[0057] In 101, in a preset state, the connection and disconnection of the bridge arm converter 3 is controlled to allow the first power battery 1 and the second power battery 2 to be charged / discharged respectively by the inductor 4, and to form a free-wheeling circuit respectively by the energy storage element 5 to realize continuous heating of the first power battery 1 and the second power battery 2.

[0058] A first bus terminal of the bridge arm converter 3 is connected to the positive pole of the first power battery 1, and a second bus terminal of the bridge arm converter 3 is connected to the negative pole of the second power battery 2. A first end of the inductor 4 is connected to the midpoint of the bridge arm converter 3, and a second end of the inductor 4 is connected to the negative pole of the first power battery 1 and the positive pole of the second power battery 2. An energy storage element 5 is connected in parallel between the positive pole of the first power battery 1 and the negative pole of the second power battery 2, and a first end of the energy storage element 5 is connected to the first bus terminal of the bridge arm converter 3, and a second end of the energy storage element 5 is connected to the second bus terminal of the bridge arm converter 3.

[0059] Through the above technical solution, a battery self-heating device is provided that uses an energy storage element to provide a free-wheeling capacity. Two power batteries are provided, and a free-wheeling energy storage element is provided that generates an oscillating current between each of the two power batteries and an inductor, in order to realize low-cost and highly efficient battery self-heating, and the stability of the total voltage of the two power batteries and the continuous flow of current in the battery can also be guaranteed, thereby ensuring the safety of the battery during the self-heating process.

[0060] In a possible embodiment, when one of the first power battery and the second power battery is charged / discharged by the inductor, the other of the first power battery and the second power battery forms a free-wheeling circuit with the energy storage element.

[0061] In a possible embodiment, the direction of current flow when one of the first power battery and the second power battery is charged / discharged by the inductor is a first direction, and the direction of circulating current flow of the other of the first power battery and the second power battery is a second direction, and the first direction is opposite to the second direction.

[0062] In a possible embodiment, the method further includes controlling the alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3 to enable the first power battery 1 and the second power battery 2 to be charged / discharged, respectively, by the inductor 4 in a preset state, and to form a free-wheeling circuit with the energy storage element 5, respectively, to realize continuous heating of the first power battery 1 and the second power battery 2.

[0063] In a possible embodiment, the method further includes that in a preset state, the alternating connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3 is controlled according to a preset duty cycle allocation setting.

[0064] In a possible embodiment, the method further includes: when, in the preset state, the upper bridge arm of the bridge arm converter 3 is in a connected state, the lower bridge arm of the bridge arm converter 3 is in a disconnected state, and the upper bridge arm of the bridge arm converter 3 is a duration that reaches a first preset duration in the preset duty cycle allocation setting, the upper bridge arm of the bridge arm converter 3 is controlled to be disconnected and the lower bridge arm of the bridge arm converter 3 is controlled to be connected. When the lower bridge arm of the bridge arm converter 3 is in a connected state, the upper bridge arm of the bridge arm converter 3 is in a disconnected state, and the lower bridge arm of the bridge arm converter 3 is a duration that reaches a second preset duration in the preset duty cycle allocation setting, the upper bridge arm of the bridge arm converter 3 is controlled to be connected and the lower bridge arm of the bridge arm converter 3 is controlled to be disconnected.

[0065] In a possible embodiment, when the upper bridge arm of the bridge arm converter 3 is in a connected state, depending on the connection time of the upper bridge arm of the bridge arm converter 3, the inductor 4 is switched from discharging energy to the first power battery 1 to receiving energy from the first power battery 1 and the energy storage element 5, and the energy storage element 5 is switched from receiving energy from the first power battery 1 and the second power battery 2 to discharging energy to the second power battery 2 and the inductor 4. When the lower bridge arm of the bridge arm converter 3 is in a connected state, depending on the connection time of the lower bridge arm of the bridge arm converter 3, the inductor 4 is switched from discharging energy to the second power battery 2 to receiving energy from the second power battery 2 and the energy storage element 5, and the energy storage element 5 is switched from receiving energy from the first power battery 1 and the second power battery 2 to discharging energy to the first power battery 1 and the inductor 4.

[0066] In a possible embodiment, a first duration during which the inductor 4 receives the energy of the first power battery 1 and the energy storage element 5 is longer than a second duration during which the inductor 4 releases the energy to the second power battery 2. A third duration during which the inductor 4 receives the energy of the second power battery 2 and the energy storage element 5 is longer than a fourth duration during which the inductor 4 releases the energy to the first power battery 1.

[0067] In a possible embodiment, the method further includes: in a preset state, a current value of the inductor 4 and / or a voltage value across the inductor 4 are obtained, and the alternating connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter 3 are controlled according to the current value and / or the voltage value.

[0068] In a possible embodiment, the inductor 4 is an inductor 4 in a drive motor of the vehicle.

[0069] In a possible embodiment, the energy storage element 5 comprises a capacitor.

[0070] In a possible embodiment, the bridge arm converter 3 is a three-phase converter and comprises three phase bridge arms.

[0071] The present disclosure further provides a vehicle, the vehicle including the battery self-heating device described above.

[0072] For the methods in the above embodiments, the specific manner of each step execution operation has already been described in detail in the embodiments related to the device, and will not be described in detail again here.

[0073] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments, and within the scope of the technical concept of the present disclosure, several simple modifications may be made to the technical solutions of the present disclosure, and these simple modifications fall within the protection scope of the present disclosure.

[0074] Furthermore, it should be noted that the various specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction, and in order to avoid unnecessary repetition, the present disclosure does not describe the various possible combination manners.

[0075] In addition, different embodiments of the present disclosure may be combined in any alternative manner without departing from the concept of the present disclosure, and these combinations should also be considered as the disclosure content of the present disclosure.

Claims

1. A battery self-heating device comprising a bridge arm converter (3), an energy storage element (5), an inductor (4), and a controller, a first bus terminal of the bridge arm converter (3) is connected to a positive electrode of a first power battery (1), a second bus terminal of the bridge arm converter (3) is connected to a negative electrode of a second power battery (2), a first end of the inductor (4) is connected to a midpoint of the bridge arm converter (3), a second end of the inductor (4) is connected to a negative electrode of the first power battery (1) and a positive electrode of the second power battery (2), the energy storage element (5) is connected in parallel between the positive electrode of the first power battery (1) and the negative electrode of the second power battery (2), a first end of the energy storage element (5) is connected to the first bus terminal of the bridge arm converter (3), and a second end of the energy storage element (5) is connected to the second bus terminal of the bridge arm converter (3); the controller is configured to control connection and disconnection of the bridge arm converter (3) to enable the first power battery (1) and the second power battery (2) to be charged / discharged by the inductor (4) in a preset state, and to form a free-wheeling circuit with the energy storage element (5) to realize continuous heating of the first power battery (1) and the second power battery (2); Battery self-heating device.

2. 2. The device according to claim 1, wherein when one of the first power battery (1) and the second power battery (2) is charged / discharged by the inductor (4), the other of the first power battery (1) and the second power battery (2) forms a free-wheeling circuit with the energy storage element (5).

3. 3. The device of claim 2, wherein a current flow direction when one of the first power battery (1) and the second power battery (2) is charged / discharged by the inductor (4) is a first direction, and a circulation current flow direction of the other of the first power battery (1) and the second power battery (2) is a second direction, the first direction being opposite to the second direction.

4. the controller is configured to control alternate connection and disconnection of an upper bridge arm and a lower bridge arm of the bridge arm converter (3) so as to enable the first power battery (1) and the second power battery (2) to be charged / discharged by the inductor (4) respectively in the preset state, and form a free-wheeling circuit with the energy storage element (5) respectively to realize continuous heating of the first power battery (1) and the second power battery (2); The device of claim 1 .

5. The controller is configured to control, in the preset state, alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter (3) according to a preset duty cycle allocation setting. The device of claim 4.

6. The controller, in the preset state, When the upper bridge arm of the bridge arm converter (3) is in a connected state and the lower bridge arm of the bridge arm converter (3) is in a disconnected state, and the upper bridge arm of the bridge arm converter (3) is at a duration that reaches a first preset duration in the preset duty cycle allocation setting, controlling the upper bridge arm of the bridge arm converter (3) to be disconnected and the lower bridge arm of the bridge arm converter (3) to be connected; When the lower bridge arm of the bridge arm converter (3) is in a connected state, the upper bridge arm of the bridge arm converter (3) is in a disconnected state, and the lower bridge arm of the bridge arm converter (3) is in a duration that reaches a second preset duration in the preset duty cycle allocation setting, the upper bridge arm of the bridge arm converter (3) is controlled to be connected and the lower bridge arm of the bridge arm converter (3) is controlled to be disconnected. The device of claim 5 configured to:

7. When the upper bridge arm of the bridge arm converter (3) is in the connected state, the inductor (4) is switched from discharging energy to the first power battery (1) to receiving energy from the first power battery (1) and the energy storage element (5), and the energy storage element (5) is switched from receiving the energy from the first power battery (1) and the second power battery (2) to discharging energy to the second power battery (2) and the inductor (4), depending on a connection time of the upper bridge arm of the bridge arm converter (3); When the lower bridge arm of the bridge arm converter (3) is in the connected state, the inductor (4) is switched from discharging energy to the second power battery (2) to receiving energy from the second power battery (2) and the energy storage element (5), and the energy storage element (5) is switched from receiving energy from the first power battery (1) and the second power battery (2) to discharging energy to the first power battery (1) and the inductor (4) according to a connection time of the lower bridge arm of the bridge arm converter (3). The device of claim 6.

8. a first duration during which the inductor (4) receives the energy of the first power battery (1) and the energy storage element (5) is longer than a second duration during which the inductor (4) releases the energy to the second power battery (2); a third duration during which the inductor (4) receives the energy of the second power battery (2) and the energy storage element (5) is longer than a fourth duration during which the inductor (4) releases the energy to the first power battery (1); The device of claim 7.

9. The controller, in the preset state, periodically transitions various elements within the device through one of four states: State 1: The upper bridge arm of the bridge arm converter (3) is connected, the lower bridge arm of the bridge arm converter (3) is disconnected, the first power battery (1) is discharged, the energy storage element (5) is discharged, the second power battery (2) is charged, the inductor (4) is charged, the device contains a discharge current and a circulating current, the discharge current flows out of the positive electrode of the first power battery (1), and the upper bridge arm of the bridge arm converter (3) is disconnected. the first power battery (1) discharges into the inductor (4), the circulating current flows out of the positive electrode of the energy storage element (5), flows through the upper bridge arm of the bridge arm converter (3), the inductor (4), and the second power battery (2), and returns to the negative electrode of the energy storage element (5), and the second power battery (2) is charged by the energy storage element (5). State 2: the upper bridge arm of the bridge arm converter (3) is disconnected, the lower bridge arm of the bridge arm converter (3) is connected, the first power battery (1) is discharged, the inductor (4) is discharged, the second power battery (2) is charged, the energy storage element (5) is charged, the device includes a charging current and a circulating current, the charging current flows from the inductor (4) to the positive electrode of the second power battery (2) and flows out of the negative electrode of the second power battery (2), and the bridge arm (4) is connected. the second power battery (2) is charged by the inductor (4), the circulating current flows out of the positive electrode of the first power battery (1), flows through the energy storage element (5), and returns to the negative electrode of the second power battery (2); the first power battery (1) is connected in series with the second power battery (2), and the first power battery (1) and the second power battery (2) both discharge into the energy storage element (5); State 3: the upper bridge arm of the bridge arm converter (3) is disconnected, the lower bridge arm of the bridge arm converter (3) is connected, the first power battery (1) is charged, the inductor (4) is charged, the second power battery (2) is discharged, the energy storage element (5) is discharged, the device includes a discharge current and a circulating current, the discharge current flows out of the positive electrode of the second power battery (2), flows through the inductor (4) and the lower bridge arm of the bridge arm converter (3), and returns to the second power battery (2), the second power battery (2) discharges to the inductor (4), the circulating current flows out of the positive electrode of the energy storage element (5), flows through the first power battery (1), the inductor (4), and the lower bridge arm of the bridge arm converter (3), and returns to the negative electrode of the energy storage element (5), and the first power battery (1) is charged; and State 4: the upper bridge arm of the bridge arm converter (3) is connected, the lower bridge arm of the bridge arm converter (3) is disconnected, the first power battery (1) is charged, the energy storage element (5) is charged, the second power battery (2) is discharged, the inductor (4) is discharged, the device contains a charging current and a circulating current, the charging current flows out of the inductor (4), through the upper bridge arm of the bridge arm converter (3), and into the positive pole of the first power battery (1). the first power battery (1) is charged by the inductor (4), the circulation current flows out of the positive electrode of the first power battery (1), flows through the energy storage element (5), and returns to the negative electrode of the second power battery (2), the first power battery (1) is connected in series with the second power battery (2), and the first power battery (1) and the second power battery (2) both discharge into the energy storage element (5). The device of claim 1 , further configured to control the

10. the controller is configured to obtain a current value of the inductor (4) and / or a voltage value across the inductor (4) in the preset state, and control alternate connection and disconnection of the upper bridge arm and the lower bridge arm of the bridge arm converter (3) according to the current value and / or the voltage value. A device according to any one of claims 4 to 8.

11. A device according to any one of the preceding claims, wherein the inductor (4) is an inductor (4) in a drive motor of a vehicle.

12. The device according to any one of the preceding claims, wherein the energy storage element (5) comprises a capacitor.

13. The device according to any one of the preceding claims, wherein the bridge arm converter (3) is a three-phase converter and comprises three bridge arms.

14. Controlling the connection and disconnection of the bridge arm converter (3) to allow the first power battery (1) and the second power battery (2) to be charged / discharged by the inductor (4) respectively in a preset state, and forming a free-wheeling circuit by the energy storage element (5) respectively to realize continuous heating of the first power battery (1) and the second power battery (2). A battery self-heating method comprising: a first bus terminal of the bridge arm converter (3) is connected to the positive electrode of the first power battery (1), a second bus terminal of the bridge arm converter (3) is connected to the negative electrode of the second power battery (2), a first end of the inductor (4) is connected to a midpoint of the bridge arm converter (3), a second end of the inductor (4) is connected to the negative electrode of the first power battery (1) and the positive electrode of the second power battery (2), the energy storage element (5) is connected in parallel between the positive electrode of the first power battery (1) and the negative electrode of the second power battery (2), a first end of the energy storage element (5) is connected to the first bus terminal of the bridge arm converter (3), and a second end of the energy storage element (5) is connected to the second bus terminal of the bridge arm converter (3). Battery self-heating method.

15. A vehicle comprising the battery self-heating device according to any one of claims 1 to 13.

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