Battery heating system, battery heating control method and vehicle

Abstract

Provided are 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; an energy storage element, the energy storage element being separately connected to a negative electrode of the first battery pack and a positive electrode of the second battery pack by means of a wire; a current sensor, the current sensor being arranged on the wire to measure a current on the wire; and a power assembly, direct current ends of the power assembly being respectively connected to a positive electrode of the first battery pack and a negative electrode of the second battery pack, and an alternating current end of the power assembly being connected to the energy storage element.

Description

Battery heating system, battery heating control method and vehicle

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202410644863.6, filed on May 22, 2024, and entitled "Battery heating system, battery heating control method and vehicle", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of vehicles, in particular, to a battery heating system, a battery heating control method and a vehicle. BACKGROUND

[0004] The power battery, as the power source of an electric vehicle, has a direct impact on the use performance of the vehicle. When the power battery is in a low-temperature environment, the charge and discharge performance of the power battery will be greatly reduced due to the decrease in activity of the positive and negative electrode materials and electrolyte.

[0005] In the related art, the battery and the energy storage element are usually cycled for charging and discharging. The battery generates a large amount of heat by using the internal resistance to achieve self-heating of the battery. SUMMARY

[0006] The present disclosure provides a battery heating system, a battery heating control method and a vehicle.

[0007] To achieve the above-mentioned purpose, in a first aspect, the present disclosure provides a battery heating system, comprising:

[0008] a battery, wherein the battery comprises a first battery pack and a second battery pack connected in series;

[0009] an energy storage element, which is connected to the negative electrode of the first battery pack and the positive electrode of the second battery pack through a wire;

[0010] a current sensor, which is arranged on the wire to detect the current on the wire; and

[0011] a power component, whose direct current end is connected to the positive electrode of the first battery pack and the negative electrode of the second battery pack, and whose alternating current end is connected to the energy storage element.

[0012] Optionally, the power component is a power component of a motor controller, the motor controller further comprising a control module, the control module being electrically connected with the current sensor, and the control module being electrically connected with the power component; the control module is configured to, in the battery self-heating process, adjust the current current on the wire to approach the target current if the current current on the wire does not match the target current.

[0013] Optionally, the control module is configured to adjust the current current on the wire to approach the target current by adjusting a heating duty cycle of the power component.

[0014] Optionally, the control module is configured to:

[0015] determine a target heating duty cycle of the power component according to a difference between the current current on the wire and the target current;

[0016] control the power component to adjust the current current on the wire to the target current according to the target heating duty cycle.

[0017] Optionally, the energy storage element is a motor, and the system further comprises a contactor arranged on a motor middle wire, wherein, in the battery self-heating process, the contactor is in a closed state.

[0018] The control module is further configured to:

[0019] acquire a rotation speed and a torque of the motor when the motor is in a working state;

[0020] determine whether a state of the contactor is abnormal according to the rotation speed and the torque.

[0021] Optionally, the control module is configured to:

[0022] if the rotation speed is greater than a preset rotation speed threshold and the torque is greater than a preset torque threshold, acquire the current current on the wire through the current sensor;

[0023] determine whether the state of the contactor is abnormal according to the current current on the wire and state information of the battery, wherein the state information is used to represent whether the battery is in a self-heating state.

[0024] Optionally, the control module is configured to, if the current current on the wire is greater than a first current threshold for a first preset time length when the state information represents that the battery is not in the self-heating state, determine that the contactor is sintered.

[0025] Optionally, the control module is configured to determine that the contactor is abnormally opened if a duration in which the current on the wire is less than the second current threshold reaches a second preset duration when the state information indicates that the battery is in the self-heating state.

[0026] Optionally, the control module is further configured to:

[0027] start battery self-heating and limit the output torque of the motor when the contactor is sintered; and / or

[0028] prohibit starting battery self-heating when the contactor is abnormally opened.

[0029] Optionally, the energy storage element is a motor; the control module includes a heating control unit, a torque control unit, and a wave generation control unit; and the power component includes a multi-phase bridge arm.

[0030] The heating control unit is connected with the current sensor and the wave generation control unit, respectively, and is configured to: in response to receiving a heating enable instruction, acquire the current on the wire through the current sensor; determine the heating duty cycle according to the current on the wire and a heating current frequency, and send the heating duty cycle to the wave generation control unit.

[0031] The torque control unit is connected with the wave generation control unit, and is configured to: in response to receiving a target output torque, determine a drive duty cycle of each phase bridge arm in the multi-phase bridge arm according to the target output torque and a battery voltage, and send the drive duty cycle of each phase bridge arm to the wave generation control unit.

[0032] The wave generation control unit is configured 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 drive duty cycle of the phase bridge arm; and control the corresponding bridge arm to act according to the control signal of each phase bridge arm, so that the motor performs the original function while the battery self-heating is realized.

[0033] In a second aspect, the present disclosure provides a battery heating control method, comprising:

[0034] During the battery self-heating process, a current on a wire is collected in real time through a current sensor on the wire;

[0035] When it is detected that the current on the wire does not match a target current, the current on the wire is adjusted to approach the target current;

[0036] 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 connected with the direct current end of the power assembly respectively, the alternating current end of the power assembly is connected with the energy storage element, and the energy storage element is connected with the negative electrode of the first battery pack and the positive electrode of the second battery pack through the wire respectively.

[0037] Optionally, the adjusting the current on the wire to be close to the target current comprises:

[0038] Adjusting the heating duty cycle of the power assembly to adjust the current on the wire to be close to the target current.

[0039] Optionally, the energy storage element is a motor, and a contactor is arranged on the motor line, wherein, during the battery self-heating process, the contactor is in a closed state.

[0040] The method further comprises:

[0041] When the motor is in a working state, the speed and torque of the motor are acquired;

[0042] According to the speed and torque, it is determined whether the state of the contactor is abnormal.

[0043] In a third aspect, the present disclosure provides a vehicle comprising the battery heating system provided in the first aspect of the present disclosure.

[0044] In the above technical solution, the current sensor arranged on the wire can acquire the current on the wire in real time, that is, the heating current of the battery, so as to ensure the accurate acquisition of the battery current, and then when the current on the wire does not match the target current, the current on the wire can be adjusted to be close to the target current, the control precision of the battery self-heating current is realized, the battery heating effect meets the expectation, and the problem that the vehicle has a risk of thermal management failure due to the mismatch between the heating effect and the expectation is effectively avoided. In addition, through battery self-heating, the battery temperature can be well maintained, the activity of the battery electrolyte and the electrochemical reaction rate are improved, and then the charge and discharge performance of the battery is improved, the service life of the battery is prolonged, and the battery self-heating has small energy loss and high heating efficiency.

[0045] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0046] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0047] FIG. 1 is a block diagram of a battery heating system, according to an example embodiment.

[0048] FIG. 2 is a circuit topology diagram of a battery heating system, according to an example embodiment.

[0049] FIG. 3 is a block diagram of a battery heating system, according to another example embodiment.

[0050] FIG. 4 is a circuit topology diagram of a battery heating system, according to another example embodiment.

[0051] FIG. 5 is a block diagram of a battery heating system, according to yet another example embodiment.

[0052] FIG. 6 is a circuit topology diagram of a battery heating system, according to yet another example embodiment.

[0053] FIG. 7 is a structural schematic diagram of a control module, according to an example embodiment.

[0054] FIG. 8 is a waveform schematic diagram of a drive duty cycle of a three-phase bridge arm, according to an example embodiment.

[0055] FIG. 9 is a waveform schematic diagram of a heating duty cycle of a power assembly, according to an example embodiment.

[0056] FIG. 10 is a waveform schematic diagram of a total duty cycle of a three-phase bridge arm, according to an example embodiment.

[0057] FIG. 11 is a schematic diagram of control signals of a three-phase bridge arm, according to an example embodiment.

[0058] FIG. 12 is a schematic diagram of an operation process of entering and exiting a battery self-heating function, according to an example embodiment.

[0059] FIG. 13 is a waveform schematic diagram of a current on a wire, according to an example embodiment.

[0060] FIG. 14 is a waveform schematic diagram of a first battery pack and a second battery pack, according to an example embodiment.

[0061] FIG. 15 is a waveform schematic diagram of a motor phase current, according to an example embodiment.

[0062] FIG. 16 is a flowchart of a battery heating control method, according to an example embodiment.

[0063] FIG. 17 is a block diagram of a vehicle, according to an example embodiment. DETAILED DESCRIPTION

[0064] The 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 illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0065] When the power battery is in a low-temperature environment, the charging and discharging performance of the battery will be greatly reduced due to the decrease in activity of the positive and negative electrode materials and the electrolyte. Therefore, the power battery needs to be heated to increase its body temperature, so as to ensure that the electric vehicle can be normally used in cold conditions.

[0066] In the related art, the battery and the energy storage element are usually cycled for charging and discharging, and the battery generates a large amount of heat by using the internal resistance to achieve self-heating of the battery. However, in the process of self-heating of the battery, the heating current cannot be accurately controlled, resulting in that the heating effect does not match the expectation, and the vehicle has a risk of thermal management failure.

[0067] The present disclosure provides a battery heating system, as shown in FIGS. 1 and 2, which can include a battery 1, a current sensor 2, an energy storage element 3, and a power assembly 41.

[0068] As shown in FIGS. 1 and 2, 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, i.e., the heating current of the battery 1; the direct current end of the power assembly 41 is connected to the positive electrode of the first battery pack 11 and the negative electrode of the second battery pack 12, and the alternating current end of the power assembly 41 is connected to the energy storage element 3.

[0069] The current sensor 2 is used to collect the current on the wire 10 in real time, which can be, for example, a Hall current sensor. During the self-heating process of the battery, if the current on the wire 10 does not match the target current, the current on the wire 10 is adjusted to approach the target current. The target current can be obtained from the vehicle controller, wherein the target current can be a preset value, and the preset value can be a calibrated value.

[0070] In addition, the battery self-heating function can completely cover the vehicle operating conditions, i.e., the battery self-heating is realized when charging, the battery self-heating is realized when parking, and the battery self-heating is realized when driving (i.e., the vehicle drives forward or back and forth at a certain speed), so that the battery can be heated at any time.

[0071] In addition, the above-mentioned energy storage element 3 can be an original device on the vehicle, for example, a motor, that is, the original device on the vehicle can be reused to realize self-heating of the battery. The above-mentioned 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 the wire 10. The motor can be a driving motor, an air conditioner compressor, etc.

[0072] In the above technical solution, the current sensor arranged on the wire can collect the current on the wire in real time, that is, the heating current of the battery, so as to ensure accurate collection of the battery current, and then when the current on the wire does not match the target current, the current on the wire is adjusted to approach the target current, the control precision of the self-heating current of the battery is realized, the battery heating effect meets the expectation, and the problem that the whole vehicle has a risk of thermal management failure due to the mismatch between the heating effect and the expectation is effectively avoided. In addition, through self-heating of the battery, the battery temperature can be well maintained, the activity of the battery electrolyte and the electrochemical reaction rate are improved, and then the charging and discharging performance of the battery is improved, and the service life of the battery is prolonged. In addition, the self-heating energy consumption of the battery is small, and the heating efficiency is high.

[0073] As shown in FIGS. 3 and 4, the above-mentioned power component 41 can be a power component of the motor controller 4. The motor controller 4 further includes a control module 42 electrically connected with the current sensor 2 and electrically connected with the power component 41. The control module 42 is configured to, during the self-heating process of the battery 1, if the current on the wire 10 does not match the target current, adjust the current on the wire 10 to approach the target current. In FIG. 3, the solid line represents a connection through an electrical hard line, that is, a hard line connection, and the dashed line represents a connection through a control signal line, that is, an electrical connection.

[0074] In a possible implementation, the control module 42 can adjust the heating duty cycle of the power component 41 to adjust the current on the wire 10 to approach the target current.

[0075] In addition, in an embodiment, the above-mentioned energy storage element 3 can be a driving motor, and the motor controller 4 can be a motor controller corresponding to the driving motor. In another embodiment, the above-mentioned energy storage element 3 can also be an air conditioner compressor, and the motor controller 4 can be a motor controller corresponding to the air conditioner compressor.

[0076] In this way, the motor and the motor controller on the vehicle are used to heat the battery, the motor and the motor controller can be reused, the motor can realize different functions according to different requirements, the whole vehicle cost, size and weight can be reduced, the production difficulty can be reduced, and the reliability of the battery heating system can be improved.

[0077] In addition, the power assembly 41 can include a multi-phase bridge arm, as shown in FIGS. 2 and 4. The power assembly 41 includes a three-phase bridge arm (referred to as an A-phase bridge arm, a B-phase bridge arm, and a C-phase bridge arm from left to right). The first bus of the three-phase bridge arm is connected to the positive electrode of the first battery pack 11, and the second bus 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 (which can be a motor) is connected to the midpoint of the three-phase bridge arm in a one-to-one correspondence, 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 wire 10. The winding has four star points according to the winding method, and one of the star points is connected to the N line connection point (i.e., the neutral point) of the motor. During the self-heating process of the battery, the three-phase winding of the motor acts as an energy storage element, and the first battery pack 11 and the second battery pack 12 are cyclically charged and discharged to achieve self-heating of the battery.

[0078] Although FIGS. 2 and 4 are illustrated by taking a three-phase bridge arm and a three-phase winding as an example, it should be understood by those skilled in the art that the number of bridge arms and the number of windings in FIGS. 2 and 4 are only examples. The number of bridge arms of the power assembly 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.

[0079] Specifically, the control module 42 can adjust the heating duty cycle of the power assembly 41 to adjust the current on the wire 10 to approach the target current by the following method:

[0080] According to the difference between the current on the wire 10 and the target current, the target heating duty cycle of the power assembly 41 is determined;

[0081] According to the target heating duty cycle, the power assembly 41 is controlled to adjust the current on the wire 10 to the target current.

[0082] Specifically, the control module 42 can input the difference between the current on the wire 10 and the target current into a proportional integral regulator (PI regulator), and the PI regulator calculates the target heating duty cycle of the power assembly 41 based on the difference. The heating duty cycles of the phase bridge arms of the power assembly 41 are equal. After the target heating duty cycle is determined, the heating duty cycles of the phase bridge arms of the power assembly 41 are all adjusted to the target heating duty cycle, so that the current on the wire 10 reaches the target current, and the heating effect meets the expectation.

[0083] It should be noted that the specific way in which the PI regulator calculates the target heating duty cycle based on the difference between the current on the wire 10 and the target current is known to those skilled in the art, and will not be described here.

[0084] As shown in FIG. 5 and FIG. 6, the energy storage element 3 is a motor, and the battery heating system can further include a contactor K1 arranged on the motor middle line. During the self-heating of the battery, the contactor K1 is in a closed state, that is, when the battery 1 meets the heating condition, the control contactor K1 is closed to make the battery 1 enter the self-heating state; when it is detected that the battery 1 no longer meets the heating condition, the contactor K1 can be controlled to be opened to make the battery 1 exit the self-heating state. Wherein, 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 condition. It should be noted that the first temperature threshold can be equal to the second temperature threshold, or can not be equal, which is not limited in the present disclosure.

[0085] The contactor K1 can have abnormal conditions such as sintering and abnormal opening, thereby affecting the normal work of the motor, the self-heating of the battery, etc. Therefore, when the motor is in a working state, the state of the contactor K1 can be detected. Specifically, the control module 42 is further configured to: when the motor is in a working state, acquire the speed and torque of the motor; and determine whether the state of the contactor K1 is abnormal according to the speed and torque of the motor.

[0086] Wherein, the control module 42 can be configured to determine whether the state of the contactor K1 is abnormal according to the speed and torque of the motor by the following way:

[0087] If the speed of the motor is greater than a preset speed threshold, and the torque of the motor is greater than a preset torque threshold, the current on the wire 10 is acquired by the current sensor 2; and whether the state of the contactor K1 is abnormal is determined according to the current on the wire 10 and the state information of the battery 1.

[0088] In the present disclosure, the state information can be used to represent whether the battery 1 is in the self-heating state. Specifically, the control module 42 can be configured to determine whether the state of the contactor K1 is abnormal according to the current on the wire 10 and the state information of the battery 1 by the following way:

[0089] When the state information represents that the battery 1 is not in the self-heating state, if the current on the wire 10 is greater than the first current threshold for a first preset time length, it is determined that the contactor K1 is sintered.

[0090] When the state information represents that the battery 1 is in the self-heating state, if the current on the wire 10 is less than the second current threshold for a second preset time length, it is determined that the contactor K1 is abnormally opened.

[0091] 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 can be equal or not equal, and the present disclosure does not make specific limitation.

[0092] When the motor is in the working state but the battery 1 is not in the self-heating state, the contactor K1 should normally be in the open state, if the current on the wire 10 is greater than the first current threshold and the duration reaches the first preset time length, it indicates that the contactor K1 is in the closed state at this time, thereby it can be determined that the contactor K1 is sintered.

[0093] In an embodiment, the motor is a driving motor, and the driving motor in the working state indicates that the vehicle is in the driving state. Therefore, when the motor is in the working state and the battery 1 is not in the self-heating state, it indicates that the vehicle is in the driving state and the battery self-heating state.

[0094] In another embodiment, the motor is an air conditioning compressor, and the air conditioning compressor in the working state indicates that the vehicle air conditioner is in the working state. Therefore, when the motor is in the working state and the battery 1 is not in the self-heating state, it indicates that the vehicle is in the air conditioning running state and the battery self-heating state.

[0095] It should be noted that the preset speed threshold corresponds to the current working condition of the vehicle, and the preset speed threshold can be different in different working conditions. Similarly, the preset torque threshold also corresponds to the current working condition of the vehicle, and the preset torque threshold can be different in different working conditions.

[0096] When the motor is in the working state but the battery 1 is in the self-heating state, the contactor K1 should normally be in the closed state, if the current on the wire 10 is less than the second current threshold and the duration reaches the second preset time length, it indicates that the contactor K1 is in the open state at this time, thereby it can be determined that the contactor K1 is abnormally opened.

[0097] In an embodiment, the motor is a driving motor, and the driving motor in the working state indicates that the vehicle is in the driving state. Therefore, when the motor is in the working state and the battery 1 is in the self-heating state, it indicates that the vehicle is in the driving state and the battery self-heating state, i.e., the battery self-heating is realized when driving.

[0098] In another embodiment, the motor is an air conditioning compressor, and the air conditioning compressor in the working state indicates that the vehicle air conditioner is in the running state. Therefore, when the motor is in the working state and the battery 1 is in the self-heating state, it indicates that the vehicle is in the air conditioning running state and the battery self-heating state.

[0099] When the state of the contactor K1 is abnormal, an abnormal alarm can be performed so that the user takes corresponding measures, for example, parking by the roadside, to ensure the safety of the vehicle. When the state of the contactor K1 is abnormal, the vehicle can also actively perform a safety control strategy to ensure normal operation of the motor. Specifically, the control module 42 is further configured to, when it is determined that the state of the contactor K1 is abnormal, perform a safety control strategy according to the abnormal state of the contactor K1.

[0100] Specifically, the control module 42 can be configured to perform the safety control strategy according to the abnormal state of the contactor K1 by the following ways:

[0101] When the contactor K1 is sintered, the battery self-heating is started, and the output torque of the motor is limited;

[0102] When the contactor K1 is abnormally disconnected, the battery self-heating is prohibited.

[0103] When the contactor K1 is sintered, in order to ensure that the motor performs the original function, for example, the function of driving the motor to drive the vehicle to travel, the function of the air conditioner compressor to regulate the temperature, the battery self-heating can be started, at this time, the heating current can be set to be very small, and at the same time, the output torque of the motor is limited to reduce the speed of the motor, so that the motor continues to perform the original function at a low speed.

[0104] In an embodiment, the motor is a driving motor, when the contactor K1 is sintered, the vehicle is in a limp-home condition (i.e., driving in a whole vehicle fault state), at this time, the output torque of the driving motor can be limited to make the vehicle travel at a low speed, so that the vehicle can travel normally and safely.

[0105] In another embodiment, the motor is an air conditioner compressor, when the contactor K1 is sintered, the output torque of the air conditioner compressor can be limited to make the air conditioner operate normally at a low power.

[0106] When the contactor K1 is sintered, the motor controller 4 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 contactor K1 is sintered, the motor controller 4 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.

[0107] When the contactor K1 is abnormally disconnected, in order to ensure that the motor performs the original function, the battery self-heating can be prohibited (i.e., the motor controller 4 receives a heating enable instruction, and the bridge arm of the power component does not act), until the abnormal state is repaired.

[0108] As shown in FIG. 6, the battery heating system further comprises a capacitor C, one end of which is connected to the positive electrode of the first battery pack 11, and the other end of which is connected to the negative electrode of the second battery pack 12. The capacitor C can filter and reduce noise during self-heating of the battery 1, so as to achieve self-heating noise reduction of the battery.

[0109] As shown in FIG. 7, the energy storage element 3 is a motor, and the control module 42 comprises a heating control unit 421, a torque control unit 422, and a wave generating control unit 423. The heating control unit 421 is connected to the current sensor 2 and the wave generating control unit 423 respectively, and is configured to: in response to receiving a heating enable instruction, acquire the current on the wire 10 through the current sensor 2; determine a heating duty cycle according to the current on the wire 10 and a heating current frequency, and send 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 configured to: in response to receiving a target output torque, determine a driving duty cycle of each phase bridge arm in the multi-phase bridge arm according to the target output torque and a battery voltage, and send the driving duty cycle of each phase bridge arm to the wave generating control unit 423; the wave generating control unit 423 is configured 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; and control the corresponding bridge arm to act according to the control signal of each phase bridge arm, so that the motor performs the original function while achieving self-heating of the battery.

[0110] In the present disclosure, the control signal of the bridge arm is the on-off signal of the bridge arm 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 battery 1 meets the heating condition, the vehicle controller sends a heating enable instruction to the heating control unit 421 when the motor is in the working state; after the heating control unit 421 receives the heating enable instruction, an instruction is sent to the contactor K1 to control the contactor K1 to close, and then the current on the wire 10 is obtained by communicating with the current sensor 2; then, according to the current on the wire 10 and the heating current frequency, the heating duty cycle of the battery 1 in the initial heating stage is calculated by the PI regulator in the heating control unit, and the waveform diagram of the heating duty cycle is shown in FIG. 8, and the heating duty cycle is sent to the wave generation control unit 423; at the same time, after the torque control unit 422 receives the target output torque sent by the vehicle controller, the target driving current corresponding to the target output torque can be determined according to the pre-established corresponding relationship between the torque and the current, and then the driving duty cycle of each phase bridge arm in the multi-phase bridge arm is determined according to the target driving current and the battery voltage through a control algorithm, and the driving duty cycle of each phase bridge arm is sent to the wave generation control unit 423, wherein the waveform diagram of the driving duty cycle of each phase bridge arm is shown in FIG. 9, wherein curve A is the driving duty cycle waveform diagram of the A-phase bridge arm in FIGS. 2 and 4, curve B is the driving duty cycle waveform diagram of the B-phase bridge arm in FIGS. 2 and 4, and curve C is the driving duty cycle waveform diagram of the C-phase bridge arm in FIGS. 2 and 4; after the wave generation control unit 423 receives 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 heating duty cycle and the driving duty cycle of each phase bridge arm in the multi-phase bridge arm are superimposed to obtain the total duty cycle of each phase bridge arm, as shown in FIG. 10, curve A1 is the total duty cycle waveform diagram of the A-phase bridge arm in FIGS. 2 and 4, curve B1 is the total duty cycle waveform diagram of the B-phase bridge arm in FIGS. 2 and 4, and curve C1 is the total duty cycle waveform diagram of the C-phase bridge arm in FIGS. 2 and 4; then, the wave generation control unit 423 generates the control signal (i.e., the pulse width modulation (PWM) signal) of each phase bridge arm according to the total duty cycle of each phase bridge arm through a hardware interface, wherein FIG. 11 is a schematic diagram of the control signal of the upper bridge arm of each phase bridge arm in FIGS. 2 and 4; finally, the wave generation control unit 423 controls the corresponding bridge arm to act according to the control signal of each phase bridge arm, so that the motor performs the original function while realizing the self-heating of the battery.

[0111] It should be noted that the specific implementation of determining the driving duty cycle of each phase bridge arm in the multi-phase bridge arm according to the target driving current and the battery voltage through a control algorithm belongs to the common knowledge of those skilled in the art, and will not be described herein.

[0112] In the above embodiments, the heating control current and the driving control current exist in the motor winding at the same time, the two functional currents are highly integrated, and the decoupling of the two functional currents is realized through the design of the heating control unit 421 and the torque control unit 422.

[0113] FIG. 12 illustrates the operation process of entering and exiting the battery self-heating function when the driving motor is in the normal driving mode. When the driving motor is in the normal driving mode, the control module 42 can close the contactor K1 in the off-wave condition (i.e., the multi-phase bridge arm of the power assembly 41 is not in action) after receiving the heating enable instruction and the target current sent by the vehicle controller, and then realize the battery self-heating function in the parking (i.e., the vehicle is stationary) and driving conditions through the torque control unit 422 and the heating control unit 421. When the heating prohibition instruction sent by the vehicle controller is received in the self-heating mode, the control module 42 opens the contactor K1 in the off-wave condition, and the vehicle returns to the normal driving mode. The control module 42 controls the contactor K1 in the off-wave condition, which can avoid the high-voltage impact on the circuit when the contactor K1 is closed.

[0114] The current of each component obtained according to the circuit topologies shown in FIGS. 2, 4, or 6 is shown in FIGS. 13-15. As shown in FIG. 13, the current on the wire (i.e., the heating current of the battery) is an alternating current with a certain frequency; as shown in FIG. 14, 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; as shown in FIG. 15, the motor phase current (i.e., the energy storage element 3 is the motor) is an alternating current combining the driving current and the heating current, which realizes the output torque and the battery self-heating function.

[0115] FIG. 16 is a flowchart illustrating a battery heating control method according to an example embodiment. As shown in FIG. 16, the battery heating control method can include the following steps.

[0116] In S101, during the battery self-heating process, the current on the wire is collected in real time by the current sensor on the wire.

[0117] In S102, when it is detected that the current on the wire does not match the target current, the current on the wire is adjusted to approach the target current.

[0118] 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 connected to the direct current end of the power assembly, the alternating current end of the power assembly is connected to the energy storage element, and 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 the wire.

[0119] In the technical solution, the current sensor arranged on the wire can collect the 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 on the wire does not match the target current, the current on the wire can be adjusted to approach the target current, the control precision of the battery self-heating current is realized, the battery heating effect meets the expectation, and the problem that the whole vehicle has a risk of thermal management failure due to the mismatch between the heating effect and the expectation is effectively avoided. In addition, through the battery self-heating, the battery temperature can be well maintained, the activity of the battery electrolyte and the electrochemical reaction rate are improved, and then the charging and discharging performance of the battery is improved, the service life of the battery is prolonged, and the battery self-heating has low energy loss and high heating efficiency.

[0120] Optionally, the adjusting the current on the wire to approach the target current comprises:

[0121] Adjusting the heating duty cycle of the power component to adjust the current on the wire to approach the target current.

[0122] Optionally, the adjusting the heating duty cycle of the power component to adjust the current on the wire to approach the target current comprises:

[0123] According to the difference between the current on the wire and the target current, determining the target heating duty cycle of the power component;

[0124] According to the target heating duty cycle, controlling the power component to adjust the current on the wire to the target current.

[0125] Optionally, the above energy storage element is a motor, and a contactor is arranged on the motor line, wherein during the battery self-heating process, the contactor is in a closed state.

[0126] The above method can further comprise:

[0127] When the motor is in a working state, acquiring the speed and torque of the motor;

[0128] According to the speed and torque, determining whether the state of the contactor is abnormal.

[0129] Optionally, according to the speed and torque, determining whether the state of the contactor is abnormal comprises:

[0130] If the speed is greater than a preset speed threshold and the torque is greater than a preset torque threshold, the current on the wire is acquired through the current sensor;

[0131] According to the current on the wire and the state information of the battery, determining whether the state of the contactor is abnormal, wherein the state information is used to represent whether the battery is in a self-heating state.

[0132] Optionally, the determining whether the state of the contactor is abnormal according to the current current on the wire and the state information of the battery comprises:

[0133] When the state information indicates that the battery is not in the self-heating state, if the current current on the wire is greater than the first current threshold for a first preset time length, it is determined that the contactor is sintered.

[0134] Optionally, the 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 comprises:

[0135] When the state information indicates that the battery is in the self-heating state, if the current current on the wire is less than the second current threshold for a second preset time length, it is determined that the contactor is abnormally disconnected.

[0136] Optionally, the above method can further comprise:

[0137] When the contactor is sintered, starting the self-heating of the battery and limiting the output torque of the motor; and / or

[0138] When the contactor is abnormally disconnected, the self-heating of the battery is prohibited.

[0139] Optionally, the energy storage element is a motor, and the power component comprises a plurality of phase bridge arms.

[0140] The above method can further comprise:

[0141] In response to receiving a heating enable instruction, acquiring the current current on the wire through a current sensor;

[0142] According to the current current on the wire and the heating current frequency, determining a heating duty cycle;

[0143] In response to receiving a target output torque, according to the target output torque and the battery voltage, determining a driving duty cycle of each phase bridge arm in the plurality of phase bridge arms;

[0144] For each phase bridge arm in the plurality of phase bridge arms, according to the heating duty cycle and the driving duty cycle of the phase bridge arm, generating a control signal of the phase bridge arm;

[0145] According to the control signal of each phase bridge arm, controlling the corresponding bridge arm to act, so that the motor performs the original function while realizing the self-heating of the battery.

[0146] As to the method in the above embodiments, the specific way in which each part performs the operation has been described in detail in the embodiments related to the battery heating system, and will not be described in detail here.

[0147] In addition, as shown in FIG. 17, the present disclosure also provides a vehicle 1000 comprising the above-mentioned battery heating system 1001 provided by the present disclosure.

[0148] The preferred embodiments of the present disclosure are described in detail above with reference to the drawings, but the present disclosure is not limited to the specific details of the above-described embodiments. Various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0149] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0150] In addition, any combination of various different embodiments of the present disclosure can also be made, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. A battery heating system, characterized by, The system comprises: a battery (1), wherein the battery (1) comprises a first battery pack (11) and a second battery pack (12) connected in series; a storage element (3) connected to a negative electrode of the first battery pack (11) and a positive electrode of the second battery pack (12) through a wire (10); a current sensor (2) arranged on the wire (10) to detect a current on the wire (10); and a power component (41) having a direct current end connected to a positive electrode of the first battery pack (11) and a negative electrode of the second battery pack (12) respectively, and having an alternating current end connected to the storage element (3).

2. The system of claim 1, wherein, The power component (41) is a power component of a motor controller (4), and the motor controller (4) further comprises a control module (42) electrically connected to the current sensor (2) and electrically connected to the power component (41); the control module (42) is configured to, during a battery self-heating process, adjust a current on the wire (10) to approach a target current if the current on the wire (10) does not match the target current.

3. The system of claim 2, wherein, The control module (42) adjusts the current on the wire (10) to approach the target current by adjusting a heating duty cycle of the power component (41).

4. The system of claim 3, wherein, The control module (41) is configured to: determine a target heating duty cycle of the power component (41) according to a difference between the current on the wire (10) and the target current; and control the power component (41) to adjust the current on the wire (10) to the target current according to the target heating duty cycle.

5. The system of any one of claims 2 to 4, wherein, The storage element (3) is a motor, and the system further comprises a contactor (K1) arranged on a motor neutral line, wherein the contactor (K1) is in a closed state during the battery self-heating process. The control module (42) is further configured to: acquire a rotating speed and a torque of the motor when the motor is in a working state; and determine whether a state of the contactor (K1) is abnormal according to the rotating speed and the torque.

6. The system of claim 5, wherein, The control module (42) is configured to: acquire the current on the wire (10) through the current sensor (2) if the rotating speed is greater than a preset rotating speed threshold and the torque is greater than a preset torque threshold; and determine whether the state of the contactor (K1) is abnormal according to the current on the wire (10) and state information of the battery (1), wherein the state information is used to represent whether the battery (1) is in a self-heating state.

7. The system of claim 6, wherein, The control module (42) is configured to determine that the contactor (K1) is sintered if a duration in which the current on the wire (10) is greater than a first current threshold reaches a first preset duration when the state information represents that the battery (1) is not in the self-heating state.

8. The system of claim 6, wherein, The control module (42) is configured to determine that the contactor (K1) is abnormally opened when the state information represents that the battery (1) is in the self-heating state, and a duration in which a current on the wire (10) is less than a second current threshold value reaches a second preset duration.

9. The system of any of claims 5-8, wherein, The control module (42) is further configured to: start battery self-heating and limit the output torque of the motor when the contactor (K1) is sintered; and / or prohibit starting battery self-heating when the contactor (K1) is abnormally opened.

10. The system of claim 3 or 4, wherein, The energy storage element (3) is a motor; the control module (42) includes a heating control unit (421), a torque control unit (422), and a wave generation control unit (423); and the power assembly (41) includes a multi-phase bridge arm. The heating control unit (421) is connected with the current sensor (2) and the wave generation control unit (423) respectively, and is configured to: in response to receiving a heating enable instruction, acquire a current on the wire (10) through the current sensor (2); determine a heating duty cycle according to the current on the wire (10) and a heating current frequency, and send the heating duty cycle to the wave generation control unit (423). The torque control unit (422) is connected with the wave generation control unit (423), and is configured to: in response to receiving a target output torque, determine a driving duty cycle of each phase bridge arm in the multi-phase bridge arm according to the target output torque and a battery voltage, and send the driving duty cycle of each phase bridge arm to the wave generation control unit (423). The wave generation control unit (423) is configured 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 corresponding bridge arm is controlled to act, so that the motor performs the original function while realizing the battery self-heating.

11. A battery heating control method, characterized by, The method comprises: acquiring a current on the wire (S101) through a current sensor on the wire during the battery self-heating process; and adjusting the current on the wire to approach the target current (S102) when it is detected that the current on the wire does not match the target current. 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 connected with a direct current end of a power assembly respectively, an alternating current end of the power assembly is connected with an energy storage element, and the energy storage element is connected with a negative electrode of the first battery pack and a positive electrode of the second battery pack through the wire.

12. The method of claim 11, wherein, The adjusting the current on the wire to approach the target current (S102) comprises: adjusting a heating duty cycle of the power assembly to adjust the current on the wire to approach the target current.

13. The method according to claim 11 or 12, characterized in that, The energy storage element is a motor, and a contactor is arranged on a motor line, wherein, during the battery self-heating process, the contactor is in a closed state. The method further comprises: acquiring a rotation speed and a torque of the motor when the motor is in a working state; Based on the rotational speed and the torque, it is determined whether a state of the contactor is abnormal.

14. A vehicle (1000), characterized in that The battery heating system (1001) according to any one of claims 1-10 is included.

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