Battery heating system, battery heating control method and vehicle

Abstract

The invention relates to a battery heating system, a battery heating control method and a vehicle. The system comprises a battery comprising a first battery pack and a second battery pack; the energy storage element is respectively connected with the negative electrode of the first battery pack and the positive electrode of the second battery pack through wires; the current sensor is arranged on the wire to detect the current on the wire; the direct current end of the power assembly is connected with the positive electrode of the first battery pack and the negative electrode of the second battery pack, and the alternating current end of the power assembly is connected with the energy storage element. Therefore, accurate collection of the battery heating current can be ensured, and when the current current on the wire is not matched with the target current, the current on the wire can be adjusted to approach the target current, so that the control precision of the battery self-heating current is realized, and the battery heating effect meets the expectation.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular, to a battery heating system, a battery heating control method and a vehicle. Background Art

[0002] As the power source of electric vehicles, power batteries have a direct impact on the performance of the vehicles. However, when the power battery is in a low temperature environment, its charge and discharge performance will be greatly reduced due to the decrease in the activity of the positive and negative electrode materials and the electrolyte of the battery. Therefore, it is necessary to heat the power battery to increase its body temperature, so as to ensure the normal use of electric vehicles in cold conditions.

[0003] In related technologies, batteries and energy storage elements are usually charged and discharged cyclically, and the battery uses internal resistance to generate a large amount of heat to achieve battery self-heating. However, during the battery self-heating process, the heating current cannot be accurately controlled, resulting in the heating effect not meeting expectations, and the vehicle is at risk of thermal management failure. Summary of the invention

[0004] In order to overcome the problems existing in the related art, the present disclosure provides a battery heating system, a battery heating control method and a vehicle.

[0005] In order to achieve the above objectives, in a first aspect, the present disclosure provides a battery heating system, comprising:

[0006] A battery, wherein the battery comprises a first battery pack and a second battery pack connected in series;

[0007] An energy storage element, wherein the energy storage element is connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through a wire;

[0008] a current sensor, the current sensor being disposed on the conductor to detect the current on the conductor; and

[0009] A power component, wherein a DC end of the power component is connected to the positive electrode of the first battery pack and the negative electrode of the second battery pack respectively, and an AC end of the power component is connected to the energy storage element.

[0010] Optionally, the power component is a power component of a motor controller, and the motor controller also includes a control module, which is electrically connected to the current sensor and the power component; the control module is used to adjust the current current on the wire to be closer to the target current if the current current on the wire does not match the target current during battery self-heating.

[0011] Optionally, the control module adjusts the heating duty cycle of the power component to adjust the current on the wire to approach the target current.

[0012] Optionally, the control module is used to:

[0013] Determining a target heating duty cycle of the power component according to a difference between a current current on the wire and the target current;

[0014] According to the target heating duty cycle, the power component is controlled to adjust the current on the wire to the target current.

[0015] Optionally, the energy storage element is a motor, and the system further comprises a contactor arranged on the center line of the motor, wherein during the self-heating process of the battery, the contactor is in a closed state;

[0016] The control module is also used for:

[0017] When the motor is in a working state, obtaining the rotation speed and torque of the motor;

[0018] It is determined whether a state of the contactor is abnormal according to the rotation speed and the torque.

[0019] Optionally, the control module is used to:

[0020] If the rotation speed is greater than a preset rotation speed threshold, and the torque is greater than a preset torque threshold, obtaining the current current on the wire through the current sensor;

[0021] Whether the state of the contactor is abnormal is determined according to the current current on the wire and the state information of the battery, wherein the state information is used to indicate whether the battery is in a self-heating state.

[0022] Optionally, the control module is used to determine that the contactor is sintered if the duration for which the current current on the wire is greater than a first current threshold reaches a first preset duration when the status information indicates that the battery is not in the self-heating state.

[0023] Optionally, the control module is used to determine that the contactor is abnormally disconnected if the duration during which the current current on the wire is less than a second current threshold reaches a second preset duration when the status information indicates that the battery is in the self-heating state.

[0024] Optionally, the control module is further used for:

[0025] When the contactor is sintered, the battery is started to self-heat and the output torque of the motor is limited; and / or

[0026] When the contactor is abnormally disconnected, self-heating of the start-up battery is prohibited.

[0027] Optionally, the energy storage element is a motor; the control module includes a heating control unit, a torque control unit and a wave control unit; the power component includes a multi-phase bridge arm;

[0028] The heating control unit is connected to the current sensor and the wave generation control unit respectively, and is used to: in response to receiving a heating enable instruction, obtain the current current on the wire through the current sensor; determine the heating duty cycle according to the current current on the wire and the heating current frequency, and send the heating duty cycle to the wave generation control unit;

[0029] The torque control unit is connected to the wave generation control unit, and is used to determine the driving duty ratio of each phase bridge arm in the multi-phase bridge arm according to the target output torque and the battery voltage in response to receiving the target output torque, and send the driving duty ratio of each phase bridge arm to the wave generation control unit;

[0030] The wave generation control unit is used to: generate a control signal for each phase bridge arm in the multi-phase bridge arm according to the heating duty cycle and the driving duty cycle of the phase bridge arm; and control the action of the corresponding bridge arm according to the control signal of each phase bridge arm, so that the motor can perform its original function while realizing self-heating of the battery.

[0031] In a second aspect, the present disclosure provides a battery heating control method, comprising:

[0032] During the self-heating process of the battery, the current on the wire is collected in real time by the current sensor on the wire;

[0033] When it is detected that the current current of the wire does not match the target current, adjusting the current current on the wire to be closer to the target current;

[0034] Wherein, the battery includes a first battery pack and a second battery pack connected in series, the positive electrode of the first battery pack and the negative electrode of the second battery pack are respectively connected to the DC end of the power component, the AC end of the power component is connected to the energy storage element, and the energy storage element is respectively connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through the wire.

[0035] Optionally, the adjusting the current on the wire to be close to the target current includes:

[0036] The heating duty cycle of the power component is adjusted to adjust the current on the wire to approach the target current.

[0037] Optionally, the energy storage element is a motor, and a contactor is provided on the center line of the motor, wherein during the self-heating process of the battery, the contactor is in a closed state;

[0038] The method further comprises:

[0039] When the motor is in a working state, obtaining the rotation speed and torque of the motor;

[0040] It is determined whether a state of the contactor is abnormal according to the rotation speed and the torque.

[0041] In a third aspect, the present disclosure provides a vehicle, comprising the battery heating system provided in the first aspect of the present disclosure.

[0042] In the above technical solution, the current sensor set on the wire can collect the current current on the wire in real time, that is, the heating current of the battery, so as to ensure the accurate collection of the battery current, and then when the current current on the wire does not match the target current, the current current on the wire can be adjusted to be close to the target current, so as to achieve the control accuracy of the battery self-heating current, so that the battery heating effect meets expectations, so as to effectively avoid the risk of thermal management failure of the whole vehicle caused by the heating effect not meeting expectations. In addition, through battery self-heating, the battery temperature can be better maintained, the battery electrolyte activity and electrochemical reaction rate can be improved, and the battery charging and discharging performance can be improved, while the battery life can be extended. In addition, the battery self-heating has low energy loss and high heating efficiency.

[0043] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0045] Figure 1 is a block diagram of a battery heating system according to an exemplary embodiment.

[0046] Figure 2 is a circuit topology diagram of a battery heating system according to an exemplary embodiment.

[0047] Figure 3 is a block diagram of a battery heating system according to another exemplary embodiment.

[0048] Figure 4 is a circuit topology diagram of a battery heating system according to another exemplary embodiment.

[0049] Figure 5 is a block diagram of a battery heating system according to yet another exemplary embodiment.

[0050] Figure 6 is a circuit topology diagram of a battery heating system according to yet another exemplary embodiment.

[0051] Figure 7 It is a schematic structural diagram of a control module according to an exemplary embodiment.

[0052] Figure 8 It is a waveform diagram of a driving duty cycle of a three-phase bridge arm according to an exemplary embodiment.

[0053] Fig. 9 It is a waveform diagram showing a heating duty cycle of a power component according to an exemplary embodiment.

[0054] Fig.10 The figure is a waveform diagram of a total duty cycle of a three-phase bridge arm according to an exemplary embodiment.

[0055] Fig.11 is a schematic diagram showing a control signal of a three-phase bridge arm according to an exemplary embodiment.

[0056] Fig.12 The present invention is a schematic diagram of an operation process of entering and exiting a battery self-heating function according to an exemplary embodiment.

[0057] Fig.13 The figure is a schematic diagram showing a waveform of a current on a wire according to an exemplary embodiment.

[0058] Fig.14 FIG. 1 is a waveform diagram of a first battery pack and a second battery pack according to an exemplary embodiment.

[0059] Fig.15 is a schematic diagram of a waveform of a motor phase current according to an exemplary embodiment.

[0060] Fig.16 The figure is a flow chart showing a battery heating control method according to an exemplary embodiment. DETAILED DESCRIPTION

[0061] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0062] The present disclosure provides a battery heating system, such as Figure 1 and Figure 2 As shown, the battery heating system may include a battery 1 , a current sensor 2 , an energy storage element 3 and a power component 41 .

[0063] like Figure 1 and Figure 2As shown, the battery 1 includes a first battery pack 11 and a second battery pack 12 connected in series; the energy storage element 3 is connected to the negative electrode of the first battery pack 11 and the positive electrode of the second battery pack 12 through a wire 10; the current sensor 2 is arranged on the wire 10 to detect the current on the wire 10, that is, the heating current of the battery 1; the DC end of the power component 41 is connected to the positive electrode of the first battery pack 11 and the negative electrode of the second battery pack 12, respectively, and the AC end of the power component 41 is connected to the energy storage element 3.

[0064] The current sensor 2 is used to collect the current on the wire 10 in real time, and it can be, for example, a Hall current sensor. During the battery self-heating process, if the current current on the wire 10 does not match the target current, the current current on the wire 10 is adjusted to be close to the target current. The target current can be obtained from the vehicle controller, and the target current can be a preset value, which can be a calibrated value.

[0065] In addition, the battery self-heating function can fully cover the entire vehicle operating conditions, that is, the battery self-heating is achieved during charging, the battery self-heating is achieved when parking, and the battery self-heating is achieved when driving (that is, the vehicle moves forward or forward and backward at a certain speed), so that the battery can be heated at any time.

[0066] In addition, the energy storage element 3 can be an existing device on the vehicle, for example, a motor, that is, the existing device on the vehicle can be reused to achieve battery self-heating, and the energy storage element 3 can also be an additional energy storage element. When the energy storage element 3 is a motor, the neutral point of the motor is connected to the negative electrode of the first battery pack 11 and the positive electrode of the second battery pack 12 through a wire 10, and the motor can be a drive motor, an air-conditioning compressor, etc.

[0067] In the above technical solution, the current sensor set on the wire can collect the current current on the wire in real time, that is, the heating current of the battery, so as to ensure the accurate collection of the battery current, and then when the current current on the wire does not match the target current, the current current on the wire can be adjusted to be close to the target current, so as to achieve the control accuracy of the battery self-heating current, so that the battery heating effect meets expectations, so as to effectively avoid the risk of thermal management failure of the whole vehicle caused by the heating effect not meeting expectations. In addition, through battery self-heating, the battery temperature can be better maintained, the battery electrolyte activity and electrochemical reaction rate can be improved, and the battery charging and discharging performance can be improved, while the battery life can be extended. In addition, the battery self-heating has low energy loss and high heating efficiency.

[0068] like Figure 3 and Figure 4As shown, the power component 41 can be a power component of the motor controller 4, and the motor controller 4 also includes a control module 42, which is electrically connected to the current sensor 2, and the control module 42 is electrically connected to the power component 41; the control module 42 is used to adjust the current current on the wire 10 to be close to the target current if the current current on the wire 10 does not match the target current during the self-heating process of the battery 1. Figure 3 In the figure, the solid line indicates connection through electrical hard wires, i.e. hard wire connection, and the dotted line indicates connection through control signal wires, i.e. electrical connection.

[0069] In a possible implementation, the control module 42 may adjust the heating duty cycle of the power component 41 to adjust the current on the wire 10 to approach the target current.

[0070] In addition, in one embodiment, the energy storage element 3 may be a drive motor, and the motor controller 4 may be a motor controller corresponding to the drive motor. In another embodiment, the energy storage element 3 may be an air conditioning compressor, and the motor controller 4 may be a motor controller corresponding to the air conditioning compressor.

[0071] In this way, by using the motor and motor controller on the vehicle to heat the battery, the motor and motor controller can be reused, so that the motor can achieve different functions according to different needs. This can not only reduce the cost, volume and weight of the vehicle, but also reduce the difficulty of production and improve the reliability of the battery heating system.

[0072] In addition, the power component 41 may include a multi-phase bridge arm, such as Figure 2 and Figure 4 As shown, the power component 41 includes a three-phase bridge arm (referred to as the A-phase bridge arm, the B-phase bridge arm, and the C-phase bridge arm from left to right). Among them, the first bus end of the three-phase bridge arm is connected to the positive electrode of the first battery pack 11, and the second bus end of the three-phase bridge arm is connected to the negative electrode of the second battery pack 12. The first end of the three-phase winding of the energy storage element 3 (specifically, it can be a motor) is connected to the midpoint of the three-phase bridge arm one by one, and the second end of the three-phase winding is connected to form a neutral point. The neutral point is connected to the negative electrode of the first battery pack 11 and the positive electrode of the second battery pack 12 through the conductor 10. Among them, the winding will have four star points according to the winding method, and one of the star points is the N line connection point (i.e., the neutral point) of the motor. During the battery self-heating process, the three-phase winding of the motor acts as an energy storage element, and is cyclically charged and discharged with the first battery pack 11 and the second battery pack 12 to achieve battery self-heating.

[0073] Although Figure 2 and Figure 4 The diagram is illustrated by taking a three-phase bridge arm and a three-phase winding as an example, but those skilled in the art should understand that Figure 2 and Figure 4 The number of bridge arm phases and the number of windings in are only examples. The number of bridge arms of the power component 41 is equal to the number of windings of the energy storage element 3, and the number of bridge arms and the number of windings of the motor are both greater than or equal to 3.

[0074] Specifically, the control module 42 can be used to adjust the heating duty cycle of the power component 41 in the following manner to adjust the current on the wire 10 to approach the target current:

[0075] Determine a target heating duty cycle of the power component 41 according to a difference between a current on the wire 10 and a target current;

[0076] According to the target heating duty cycle, the power component 41 is controlled to adjust the current on the wire 10 to the target current.

[0077] Specifically, the control module 42 can input the difference between the current current on the wire 10 and the target current into a proportional integral controller (PI regulator for short), and the PI regulator calculates the target heating duty cycle of the power component 41 based on the difference, wherein the heating duty cycles of the bridge arms of each phase of the power component 41 are equal. After determining the target heating duty cycle, the heating duty cycles of the bridge arms of each phase of the power component 41 can be adjusted to the target heating duty cycle, so that the current current on the wire 10 reaches the target current, so that the heating effect meets expectations.

[0078] It should be noted that the specific manner in which the PI regulator calculates the target heating duty cycle based on the difference between the current current on the wire 10 and the target current is common knowledge to those skilled in the art and will not be elaborated here.

[0079] like Figure 5 and Figure 6 As shown, the energy storage element 3 is a motor, and the battery heating system may further include a contactor K1 disposed on the center line of the motor, wherein during the battery self-heating process, the contactor K1 is in a closed state, that is, when the battery 1 meets the heating conditions, the contactor K1 is controlled to be closed so that the battery 1 enters the self-heating state; when it is detected that the battery 1 no longer meets the heating conditions, the contactor K1 may be controlled to be disconnected so that the battery 1 exits the self-heating state. When the temperature of the first battery pack is less than the first temperature threshold or the temperature of the second battery pack is less than the second temperature threshold, it is determined that the battery 1 meets the heating conditions. It should be noted that the first temperature threshold may be equal to the second temperature threshold, or may not be equal, and the present disclosure does not make specific limitations.

[0080] The contactor K1 may be sintered, disconnected abnormally, or other abnormal conditions, thereby affecting the normal operation of the motor, the self-heating of the battery, etc. Therefore, when the motor is in operation, it is possible to detect whether the state of the contactor K1 is abnormal. Specifically, the control module 42 is also used to: when the motor is in operation, obtain the speed and torque of the motor; and determine whether the state of the contactor K1 is abnormal based on the speed and torque of the motor.

[0081] The control module 42 can be used to determine whether the state of the contactor K1 is abnormal according to the speed and torque of the motor in the following manner:

[0082] If the motor speed is greater than the preset speed threshold and the motor torque is greater than the preset torque threshold, the current current on the wire 10 is obtained through the current sensor 2; based on the current current on the wire 10 and the status information of the battery 1, it is determined whether the state of the contactor K1 is abnormal.

[0083] In the present disclosure, the state information can be used to characterize whether the battery 1 is in a self-heating state. Specifically, the control module 42 can be used to determine whether the state of the contactor K1 is abnormal according to the current current on the wire 10 and the state information of the battery 1 in the following manner:

[0084] When the state information indicates that the battery 1 is not in a self-heating state, if the duration of the current on the wire 10 being greater than the first current threshold reaches a first preset duration, it is determined that the contactor K1 is sintered;

[0085] When the state information indicates that the battery 1 is in a self-heating state, if the duration during which the current current on the wire 10 is less than the second current threshold reaches a second preset duration, it is determined that the contactor K1 is abnormally disconnected.

[0086] In the present disclosure, the first current threshold is greater than the second current threshold; the first preset time length and the second preset time length may be equal or may not be equal, and the present disclosure does not make any specific limitation.

[0087] When the motor is in working state but the battery 1 is not in self-heating state, the contactor K1 should be in the disconnected state under normal circumstances. If the current current on the wire 10 is greater than the first current threshold value and the duration reaches the first preset duration, it indicates that the contactor K1 is in the closed state at this time. Therefore, it can be determined that the contactor K1 is sintered.

[0088] In one embodiment, the above-mentioned motor is a drive motor, and the drive motor is in a working state, which indicates that the vehicle is in a driving state. Therefore, when the motor is in a working state and the battery 1 is not in a self-heating state, it indicates that the vehicle is in a driving state and there is no battery self-heating.

[0089] In another embodiment, the above-mentioned motor is an air-conditioning compressor, and the air-conditioning compressor is in a working state, which indicates that the vehicle air-conditioning is in a working state. Therefore, when the motor is in a working state and the battery 1 is not in a self-heating state, it indicates that the vehicle is in a condition where the air-conditioning is running and there is no battery self-heating.

[0090] It should be noted that the above-mentioned preset speed threshold corresponds to the current operating condition of the vehicle. Under different operating conditions, the preset speed threshold may be different; similarly, the above-mentioned preset torque threshold also corresponds to the current operating condition of the vehicle. Under different operating conditions, the preset torque threshold may be different.

[0091] When the motor is in working state but the battery 1 is in self-heating state, the contactor K1 should be in closed state under normal circumstances. If the current current on the wire 10 is less than the second current threshold and the duration reaches the second preset duration, it indicates that the contactor K1 is in the disconnected state at this time. Therefore, it can be determined that the contactor K1 is abnormally disconnected.

[0092] In one embodiment, the above-mentioned motor is a drive motor, and the drive motor is in a working state, which indicates that the vehicle is in a driving state. Therefore, when the motor is in a working state and the battery 1 is in a self-heating state, it indicates that the vehicle is in a driving state and the battery is self-heating, that is, the battery self-heating is achieved during driving.

[0093] In another embodiment, the above-mentioned motor is an air-conditioning compressor, and the air-conditioning compressor is in a working state, which indicates that the vehicle air-conditioning is in an operating state. Therefore, when the motor is in a working state and the battery 1 is in a self-heating state, it indicates that the vehicle is in a condition where the air-conditioning is running and the battery is self-heating.

[0094] When the state of the contactor K1 is abnormal, an abnormal alarm can be issued so that the user can take corresponding measures, such as pulling over to ensure the safety of the vehicle. When the state of the contactor K1 is abnormal, the vehicle can also actively execute the safety control strategy to ensure the normal operation of the motor. Specifically, the control module 42 is also used to execute the safety control strategy according to the abnormal state of the contactor K1 when it is determined that the state of the contactor K1 is abnormal.

[0095] Specifically, the control module 42 can be used to execute the safety control strategy according to the abnormal state of the contactor K1 in the following ways:

[0096] When contactor K1 is sintered, the battery self-heats and the output torque of the motor is limited;

[0097] When contactor K1 is abnormally disconnected, self-heating of the starting battery is prohibited.

[0098] When the contactor K1 is sintered, in order to ensure that the motor performs its original functions, for example, the drive motor performs the function of driving the vehicle and the air-conditioning compressor performs the function of temperature regulation, the battery self-heating can be started. At this time, the heating current can be set very small. At the same time, the output torque of the motor is limited to reduce the speed of the motor and ensure that the motor continues to perform its original function at a low speed.

[0099] In one embodiment, the above-mentioned motor is a drive motor. When the contactor K1 is sintered, the vehicle is in a limp home condition (i.e., driving under a complete vehicle failure state). At this time, the output torque of the drive motor can be limited to allow the vehicle to travel at a low speed, thereby ensuring normal and safe driving of the vehicle.

[0100] In another embodiment, the motor is an air-conditioning compressor. When the contactor K1 is sintered, the output torque of the air-conditioning compressor can be limited so that the air-conditioning can operate normally at low power.

[0101] When the motor controller 4 detects that the contactor K1 is sintered, it can only respond to part of the target output torque sent by the vehicle controller, for example, only respond to 40% or 50% of the target output torque; of course, when the motor controller 4 detects that the contactor K1 is sintered, it can send the abnormal state to the vehicle controller, and then the vehicle controller actively reduces the target output torque sent to the motor controller 4, for example, the target output torque sent to the motor controller 4 is 40% or 50% of the original.

[0102] When the contactor K1 is abnormally disconnected, in order to ensure that the motor performs its original function, the self-heating of the startup battery can be prohibited (that is, the motor controller 4 receives the heating enable instruction, and the bridge arm of the power component does not operate) until the abnormal state is repaired.

[0103] like Figure 6 As shown, the battery heating system further includes a capacitor C, wherein one end of the capacitor C is connected to the positive electrode of the first battery pack 11, and the other end of the capacitor C is connected to the negative electrode of the second battery pack 12. The capacitor C can perform filtering and noise reduction during the self-heating process of the battery 1 to achieve battery self-heating noise reduction.

[0104] like Figure 7As shown, the energy storage element 3 is a motor, and the control module 42 includes a heating control unit 421 , a torque control unit 422 and a wave generation control unit 423 . Among them, the heating control unit 421 is connected to the current sensor 2 and the wave-generating control unit 423 respectively, and is used for: in response to receiving the heating enable instruction, obtaining the current current on the wire 10 through the current sensor 2; determining the heating duty cycle according to the current current on the wire 10 and the heating current frequency, and sending the heating duty cycle to the wave-generating control unit 423; the torque control unit 422 is connected to the wave-generating control unit 423, and is used for determining the driving duty cycle of each phase bridge arm in the multi-phase bridge arm according to the target output torque and the battery voltage in response to receiving the target output torque, and sending the driving duty cycle of each phase bridge arm to the wave-generating control unit 423; the wave-generating control unit 423 is used for: for each phase bridge arm in the multi-phase bridge arm, generating a control signal of the phase bridge arm according to the heating duty cycle and the driving duty cycle of the phase bridge arm; according to the control signal of each phase bridge arm, controlling the action of the corresponding bridge arm, so that the motor can perform its original function while realizing battery self-heating.

[0105] In the present disclosure, the control signal of the bridge arm is the bridge arm turn-on and turn-off signal of the power component. The heating current frequency is a preset value, which can be calibrated according to the characteristics of the battery. When the motor is in working state, when the battery 1 meets the heating conditions, the vehicle controller sends a heating enable instruction to the heating control unit 421; after receiving the heating enable instruction, the heating control unit 421 sends an instruction to the contactor K1 to control the contactor K1 to close, and then communicates with the current sensor 2 to obtain the current current on the wire 10; then, according to the current current on the wire 10 and the heating current frequency, the PI regulator in the heating control unit is used to calculate the heating duty cycle of the battery 1 in the initial heating stage. The waveform of the heating duty cycle is shown as follows. Figure 8 As shown, the heating duty cycle is sent to the wave control unit 423; at the same time, after receiving the target output torque sent by the vehicle controller, the torque control unit 422 can determine the target drive current corresponding to the target output torque according to the pre-established correspondence between the torque and the current. After that, according to the target drive current and the battery voltage, the drive duty cycle of each phase bridge arm in the multi-phase bridge arm is determined by the control algorithm, and the drive duty cycle of each phase bridge arm is sent to the wave control unit 423, wherein the waveform diagram of the drive duty cycle of each phase bridge arm is as shown in Fig. 9 As shown, curve A is Figure 2 and Figure 4 The driving duty cycle waveform of the A phase bridge arm, curve B is Figure 2 and Figure 4 The driving duty cycle waveform of the B phase bridge arm, curve C is Figure 2 and Figure 4The driving duty cycle waveform of the C-phase bridge arm in FIG. 4 is a waveform diagram; after receiving the heating duty cycle sent by the heating control unit 421 and the driving duty cycle of each phase bridge arm sent by the torque control unit 422, the wave control unit 423 can superimpose the heating duty cycle and the driving duty cycle of the phase bridge arm for each phase bridge arm in the multi-phase bridge arm to obtain the total duty cycle of the phase bridge arm, such as Fig.10 As shown, curve A1 is Figure 2 and Figure 4 The total duty cycle waveform of the A phase bridge arm, curve B1 is Figure 2 and Figure 4 The total duty cycle waveform of the B phase bridge arm, curve C1 is Figure 2 and Figure 4 The total duty cycle waveform of the C phase bridge arm; then, the wave control unit 423 generates a control signal (i.e., a pulse width modulation (PWM) signal) of the phase bridge arm through a hardware interface according to the total duty cycle of the phase bridge arm, wherein, Fig.11 for Figure 2 and Figure 4 Finally, the wave control unit 423 controls the action of the corresponding bridge arm according to the control signal of each phase bridge arm, so that the motor can perform its original function while realizing battery self-heating.

[0106] It should be noted that the specific implementation method of determining the driving duty cycle of each phase bridge arm in the multi-phase bridge arm through a control algorithm according to the target driving current and the battery voltage belongs to the common knowledge of those skilled in the art and will not be elaborated in this disclosure.

[0107] In the above embodiment, the heating control current and the driving control current exist simultaneously inside the motor winding, and the two functional currents are highly integrated. The decoupling of the two functional currents is achieved through the design of the heating control unit 421 and the torque control unit 422.

[0108] Fig.12Taking the motor as a driving motor as an example, it describes the operation process of the battery 1 self-heating function entering and exiting when the driving motor is in the normal driving mode. When the driving motor is in the normal driving mode, upon receiving the heating enable command and target current sent by the vehicle controller, the control module 42 can close the contactor K1 in the off-wave state (i.e., the multi-phase bridge arm of the power component 41 does not operate), and then realize the battery self-heating function under parking (i.e., the vehicle stops) and driving through the above-mentioned torque control unit 422 and heating control unit 421; when receiving the heating prohibition command sent by the vehicle controller in the self-heating mode, the control module 42 disconnects the contactor K1 in the off-wave state, and the vehicle returns to the normal driving mode. The control module 42 controls the contactor K1 to operate in the off-wave state, which can avoid the high-voltage impact on the circuit when the contactor K1 is closed.

[0109] according to Figure 2 , Figure 4 or Figure 6 The circuit topology shown in the figure gives the current of each component. Figures 13 to 15 As shown. Fig.13 As shown, the current on the wire (i.e., the heating current of the battery) is an alternating current with a certain frequency; Fig.14 As shown, the first battery pack 11 and the second battery pack 12 are positive and negative alternating currents, and the two battery packs charge and discharge each other, and the current amplitude is half of the current amplitude on the wire 10; Fig.15 As shown, the motor phase current (ie, the energy storage element 3 is a motor) is an alternating current that combines two current frequencies, a driving current and a heating current, to achieve output torque and battery self-heating functions.

[0110] Fig.16 FIG. 1 is a flow chart showing a battery heating control method according to an exemplary embodiment. Fig.16 As shown, the battery heating control method may include the following steps.

[0111] In S101, during the battery self-heating process, the current on the wire is collected in real time by a current sensor on the wire.

[0112] In S102, when it is detected that the current current on the wire does not match the target current, the current current on the wire is adjusted to be closer to the target current.

[0113] The battery includes a first battery pack and a second battery pack connected in series, the positive electrode of the first battery pack and the negative electrode of the second battery pack are respectively connected to the DC end of the power component, the AC end of the power component is connected to the energy storage element, and the energy storage element is respectively connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through a wire.

[0114] In the above technical solution, the current sensor set on the wire can collect the current current on the wire in real time, that is, the heating current of the battery, so as to ensure the accurate collection of the battery current, and then when the current current on the wire does not match the target current, the current current on the wire can be adjusted to be close to the target current, so as to achieve the control accuracy of the battery self-heating current, so that the battery heating effect meets expectations, so as to effectively avoid the risk of thermal management failure of the whole vehicle caused by the heating effect not meeting expectations. In addition, through battery self-heating, the battery temperature can be better maintained, the battery electrolyte activity and electrochemical reaction rate can be improved, and the battery charging and discharging performance can be improved, while the battery life can be extended. In addition, the battery self-heating has low energy loss and high heating efficiency.

[0115] Optionally, adjusting the current on the wire to approach the target current includes:

[0116] The heating duty cycle of the power component is adjusted to adjust the current on the wire to approach the target current.

[0117] Optionally, adjusting the heating duty cycle of the power component to adjust the current on the wire to approach the target current, including:

[0118] Determining a target heating duty cycle of the power component according to a difference between a current on the wire and a target current;

[0119] According to the target heating duty cycle, the power component is controlled to adjust the current on the wire to the target current.

[0120] Optionally, the energy storage element is a motor, and a contactor is provided on the center line of the motor, wherein during the self-heating process of the battery, the contactor is in a closed state;

[0121] The above method may further include:

[0122] When the motor is in working state, the speed and torque of the motor are obtained;

[0123] Determine whether the contactor status is abnormal based on the speed and torque.

[0124] Optionally, determining whether the state of the contactor is abnormal based on the rotation speed and the torque includes:

[0125] If the speed is greater than the preset speed threshold, and the torque is greater than the preset torque threshold, the current on the wire is obtained through the current sensor;

[0126] Whether the state of the contactor is abnormal is determined based on the current on the wire and the state information of the battery, wherein the state information is used to indicate whether the battery is in a self-heating state.

[0127] Optionally, determining whether the state of the contactor is abnormal according to the current current on the wire and the state information of the battery includes:

[0128] When the state information indicates that the battery is not in a self-heating state, if the duration of the current on the wire being greater than the first current threshold reaches a first preset duration, it is determined that the contactor is sintered.

[0129] Optionally, determining whether the state of the contactor is abnormal according to the current current on the wire and the state information of the battery further includes:

[0130] When the state information indicates that the battery is in a self-heating state, if the duration during which the current current on the wire is less than the second current threshold reaches a second preset duration, it is determined that the contactor is abnormally disconnected.

[0131] Optionally, the above method may further include:

[0132] In case of contactor sintering, the battery self-heats and the output torque of the motor is limited; and / or

[0133] When the contactor is abnormally disconnected, it is prohibited to start the battery self-heating.

[0134] Optionally, the energy storage element is a motor, and the power assembly includes a multi-phase bridge arm;

[0135] The above method may further include:

[0136] In response to receiving the heating enable instruction, obtaining the current current on the wire through the current sensor;

[0137] Determine the heating duty cycle according to the current on the wire and the heating current frequency;

[0138] In response to receiving the target output torque, determining a driving duty ratio of each phase bridge arm in the multi-phase bridge arm according to the target output torque and the battery voltage;

[0139] For each phase bridge arm in the multi-phase bridge arm, a control signal of the phase bridge arm is generated according to the heating duty cycle and the driving duty cycle of the phase bridge arm;

[0140] According to the control signal of each phase bridge arm, the corresponding bridge arm is controlled to operate so that the motor can perform its original function while achieving self-heating of the battery.

[0141] Regarding the method in the above embodiment, the specific manner in which each part performs the operation has been described in detail in the embodiment of the battery heating system, and will not be elaborated here.

[0142] In addition, the present disclosure also provides a vehicle, comprising the battery heating system provided by the present disclosure.

[0143] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0144] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0145] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A battery heating system, characterized in that: include: A battery, wherein the battery comprises a first battery pack and a second battery pack connected in series; An energy storage element, wherein the energy storage element is connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through a wire; a current sensor, the current sensor being disposed on the conductor to detect the current on the conductor; and A power component, wherein a DC end of the power component is connected to the positive electrode of the first battery pack and the negative electrode of the second battery pack respectively, and an AC end of the power component is connected to the energy storage element.

2. The system according to claim 1, characterized in that The power component is a power component of a motor controller, and the motor controller also includes a control module, which is electrically connected to the current sensor and the power component; the control module is used to adjust the current current on the wire to be closer to the target current if the current current on the wire does not match the target current during the battery self-heating process.

3. The system according to claim 2, characterized in that The control module adjusts the current on the wire to approach the target current by adjusting the heating duty cycle of the power component.

4. The system according to claim 3, characterized in that The control module is used for: Determining a target heating duty cycle of the power component according to a difference between a current current on the wire and the target current; According to the target heating duty cycle, the power component is controlled to adjust the current on the wire to the target current.

5. The system according to claim 2, characterized in that The energy storage element is a motor, and the system further comprises a contactor arranged on the center line of the motor, wherein during the self-heating process of the battery, the contactor is in a closed state; The control module is also used for: When the motor is in a working state, obtaining the rotation speed and torque of the motor; It is determined whether a state of the contactor is abnormal according to the rotation speed and the torque.

6. The system according to claim 5, characterized in that The control module is used for: If the rotation speed is greater than a preset rotation speed threshold, and the torque is greater than a preset torque threshold, obtaining the current current on the wire through the current sensor; Whether the state of the contactor is abnormal is determined according to the current current on the wire and the state information of the battery, wherein the state information is used to indicate whether the battery is in a self-heating state.

7. The system according to claim 6, characterized in that The control module is used for determining that the contactor is sintered if the duration for which the current current on the wire is greater than a first current threshold reaches a first preset duration when the status information indicates that the battery is not in the self-heating state.

8. The system according to claim 6, characterized in that The control module is used for determining that the contactor is abnormally disconnected if the duration during which the current current on the wire is less than the second current threshold reaches a second preset duration when the status information indicates that the battery is in the self-heating state.

9. The system according to any one of claims 5 to 8, characterized in that: The control module is also used for: When the contactor is sintered, the battery is started to self-heat and the output torque of the motor is limited; and / or When the contactor is abnormally disconnected, self-heating of the start-up battery is prohibited.

10. The system according to claim 3 or 4, characterized in that: The energy storage element is a motor; the control module includes a heating control unit, a torque control unit and a wave control unit; the power component includes a multi-phase bridge arm; The heating control unit is connected to the current sensor and the wave generation control unit respectively, and is used to: in response to receiving a heating enable instruction, obtain the current current on the wire through the current sensor; determine the heating duty cycle according to the current current on the wire and the heating current frequency, and send the heating duty cycle to the wave generation control unit; The torque control unit is connected to the wave generation control unit, and is used to determine the driving duty ratio of each phase bridge arm in the multi-phase bridge arm according to the target output torque and the battery voltage in response to receiving the target output torque, and send the driving duty ratio of each phase bridge arm to the wave generation control unit; The wave generation control unit is used to: for each phase bridge arm in the multi-phase bridge arm, generate a control signal of the phase bridge arm according to the heating duty cycle and the driving duty cycle of the phase bridge arm; According to the control signal of each phase bridge arm, the action of the corresponding bridge arm is controlled so that the motor can perform its original function while achieving self-heating of the battery.

11. A battery heating control method, characterized in that: include: During the self-heating process of the battery, the current on the wire is collected in real time by the current sensor on the wire; When it is detected that the current current of the wire does not match the target current, adjusting the current current on the wire to be closer to the target current; Wherein, the battery includes a first battery pack and a second battery pack connected in series, the positive electrode of the first battery pack and the negative electrode of the second battery pack are respectively connected to the DC end of the power component, the AC end of the power component is connected to the energy storage element, and the energy storage element is respectively connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through the wire.

12. The method according to claim 11, characterized in that The adjusting the current on the wire to be close to the target current includes: The heating duty cycle of the power component is adjusted to adjust the current on the wire to approach the target current.

13. The method according to claim 11, characterized in that The energy storage element is a motor, and a contactor is arranged on the center line of the motor, wherein during the self-heating process of the battery, the contactor is in a closed state; The method further comprises: When the motor is in a working state, obtaining the rotation speed and torque of the motor; It is determined whether a state of the contactor is abnormal according to the rotation speed and the torque.

14. A vehicle, characterized in that: The battery heating system comprises the battery heating system according to any one of claims 1 to 10.

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