Heating method, storage medium, and electric vehicle

Abstract

A heating method, which is applied to a heating system that comprises an electric motor and a traction battery. The heating method comprises: measuring the rotational speed of an electric motor; when the rotational speed of the electric motor is less than a first set value, controlling a traction battery to supply power to the electric motor to increase the rotational speed of the electric motor, so as to use the internal resistance of the traction battery to heat the traction battery and use the internal resistance of the electric motor to heat the electric motor during power supplying; and when the rotational speed of the electric motor reaches a second set value, recovering kinetic energy of the electric motor to charge the traction battery and reduce the rotational speed of the electric motor, so as to use the internal resistance of the traction battery to heat the traction battery and use the internal resistance of the electric motor to heat the electric motor during kinetic energy recovery. Further included are a storage medium and an electric vehicle.

Description

Heating method, storage medium and electric vehicle

[0001] This application claims priority to Chinese Patent Application No. 202410457006.5, filed on April 16, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of motor heating, in particular to a heating method, a storage medium and an electric vehicle. BACKGROUND

[0003] Under low temperature environment, the performance of power battery is poor, which seriously affects the power performance and development of electric vehicles. In order to enable electric vehicles to run well in cold regions, it is necessary to heat the power battery and motor to an appropriate temperature before starting the electric vehicle.

[0004] Air temperature has an impact on the ion activity of lithium batteries, which in turn affects the endurance mileage and charge-discharge performance, so the endurance mileage of electric vehicles will decrease to varying degrees in winter. The existing heating technology is to set up independent heating equipment such as PTC on the electric vehicle. This heating method has two shortcomings: low efficiency and space occupation. TECHNICAL PROBLEM

[0005] The main purpose of the present application is to provide a heating method, which aims to improve the heating efficiency of the battery and the motor and save the space of the electric vehicle. TECHNICAL SOLUTION

[0006] To achieve the above purpose, the heating method provided by the present application is applied to a heating system comprising a motor and a power battery; the heating method comprises:

[0007] detecting the motor speed;

[0008] when the motor speed is less than a first set value, controlling the power battery to supply power to the motor to increase the motor speed, so as to heat the power battery by using the internal resistance of the power battery and heat the motor by using the internal resistance of the motor during the power supply process;

[0009] when the motor speed reaches a second set value, recovering the motor kinetic energy to charge the power battery and reducing the motor speed, so as to heat the power battery by using the internal resistance of the power battery and heat the motor by using the internal resistance of the motor during the kinetic energy recovery process.

[0010] In an embodiment, after the motor speed reaches the second set value, the motor kinetic energy is recovered to charge the power battery and the motor speed is reduced, so as to heat the power battery by using the internal resistance of the power battery and heat the motor by using the internal resistance of the motor during the kinetic energy recovery process, the heating method further comprises:

[0011] In the process of recovering kinetic energy, the step of detecting the motor speed is performed.

[0012] In an embodiment, before the step of detecting the motor speed, the method further comprises:

[0013] detecting the temperature of the power battery;

[0014] when the temperature of the power battery is less than a first temperature value, the step of detecting the motor speed is performed;

[0015] when the temperature of the power battery is greater than a second temperature value, the step of detecting the motor speed is stopped.

[0016] In an embodiment, before the step of detecting the temperature of the power battery, the method further comprises:

[0017] disconnecting the power connection between the motor and the power transmission device to avoid driving the vehicle to move when the motor rotates.

[0018] In an embodiment, when the motor speed is less than a first set value, the step of controlling the power battery to supply power to the motor to increase the motor speed specifically comprises:

[0019] increasing the motor speed value by changing the current or voltage output by the power battery to the motor.

[0020] In an embodiment, when the motor speed reaches a second set value, the step of recovering the kinetic energy of the motor to charge the power battery and reduce the motor speed specifically comprises:

[0021] rectifying the alternating current output by the motor in the generator state to charge the power battery;

[0022] In the process of converting the kinetic energy of the motor into electrical energy, the speed of the motor is reduced.

[0023] In an embodiment, the heating method further comprises:

[0024] distributing the temperature rise between the motor and the power battery through the battery cooling liquid.

[0025] In an embodiment, the heating system uses a switching vector control technology to control the motor.

[0026] The heating method further comprises:

[0027] when battery heating is the main heating requirement, reducing the proportion of time that the heating system works in the zero vector state;

[0028] when motor heating is the main heating requirement, increasing the proportion of time that the heating system works in the zero vector state.

[0029] The application further provides a storage medium, wherein the storage medium stores a battery active heating program, and the battery active heating program is executed by a processor to realize the steps of the heating method.

[0030] The application further provides an electric vehicle, which comprises the storage medium. Advantages

[0031] The application discloses a heating method, a storage medium and an electric vehicle, wherein the heating method is applied to a heating system comprising a motor and a power battery; the heating method comprises the following steps: detecting a motor rotating speed; when the motor rotating speed is less than a first set value, controlling the power battery to supply power to the motor to increase the motor rotating speed, so that the power battery is heated by the internal resistance of the power battery and the motor is heated by the internal resistance of the motor during the power supply process; and when the motor rotating speed reaches a second set value, recovering motor kinetic energy to charge the power battery to reduce the motor rotating speed, so that the power battery is heated by the internal resistance of the power battery and the motor is heated by the internal resistance of the motor during the kinetic energy recovery process. The application can heat the power battery and the motor by monitoring the motor rotating speed and controlling the power battery and the motor to be charged and discharged continuously, so that the motor rotating speed is kept in a certain fluctuation range. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0033] Fig. 1 is a flowchart of an embodiment of the heating method of the present application;

[0034] Fig. 2 is a voltage vector diagram of another embodiment of the heating method of the present application;

[0035] Fig. 3 is a rotating speed diagram of still another embodiment of the heating method of the present application;

[0036] Fig. 4 is a flowchart of still another embodiment of the heating method of the present application;

[0037] Fig. 5 is a flowchart of still another embodiment of the heating method of the present application.

[0038] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. Embodiments of the present application

[0039] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0040] It should be noted that all the direction indications (such as up, down, left, right, front, back, and the like) in the embodiments of the present application are only used to explain the relative position relationship, movement condition and the like between components in a certain posture (as shown in the drawings), and if the certain posture changes, the direction indications also change accordingly.

[0041] In the present application, unless specifically defined and limited otherwise, the terms "connection", "fixation" and the like should be understood in a broad sense, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0043] The air temperature has an impact on the ion activity of the lithium battery, and further affects the endurance mileage and charge-discharge performance, so the endurance mileage of the electric vehicle will be reduced to different degrees in winter. The existing heating technology is to set an independent heating device such as PTC on the electric vehicle, and this heating method has two shortcomings: low efficiency and large space occupation. The present application realizes the mutual charge-discharge between the battery and the motor through motor control, utilizes the heat generated by the battery internal resistance, motor copper loss and motor iron loss to realize the temperature rise of the battery and the motor.

[0044] In the process of charging and discharging of the battery and the motor, the forward acceleration / reverse acceleration and the forward braking / reverse braking modes of the motor can be regarded as two modes of discharging the battery to the motor and charging the battery from the motor. The energy conversion is as follows: forward acceleration: the electric energy is converted into the mechanical energy and the internal energy of the motor and the magnetic field energy stored in the inductor; forward braking: the energy conversion is the mechanical energy of the motor and the magnetic field energy stored in the inductor into the electric energy and the internal energy. In the process of the motor from speed 1 (low speed) to speed 2 (high speed) and then to speed 1, the mechanical energy of the motor almost does not change after one cycle and can be ignored. In one cycle, the alternating current flowing through the battery generates heat, which can cause the temperature rise of the battery and the motor. The internal energy of the motor can be used to heat the battery coolant to further realize the temperature rise distribution between the battery and the motor.

[0045] The application discloses a heating method applied to a heating system comprising a motor and a power battery; the heating method comprises:

[0046] Step S10, detecting the motor speed;

[0047] Step S20, when the motor speed is less than a first set value, controlling the power battery to supply power to the motor to increase the motor speed, so as to heat the power battery by the internal resistance of the power battery and heat the motor by the internal resistance of the motor in the process of supplying power.

[0048] Step S30, when the motor speed reaches a second set value, recovering the motor kinetic energy to charge the power battery and reduce the motor speed, so as to heat the power battery by the internal resistance of the power battery and heat the motor by the internal resistance of the motor in the process of recovering the kinetic energy.

[0049] In combination with the actual application scene, the user generally preheats the vehicle before driving, including heating the motor and the power battery in the vehicle. At the beginning of the heating stage, the speed of the motor is low; possibly the motor speed is zero. At this time, the motor speed is less than the first set value, the power battery is controlled to supply power to the motor to increase the motor speed; at this time, the motor is in the state of the electric motor. In the process of supplying power, the power battery and the motor form a power supply loop, the power supply loop has current passing through, and the power battery and the motor exchange energy through the power supply loop to convert the electric energy of the power battery into the mechanical energy of the motor. It is explained that the power battery has an internal resistance, when the current flows through the internal resistance of the power battery, the internal resistance adds to the power battery under the action of the current thermal effect; in addition, the motor also has resistive elements, for example: coil reactance and wire resistance. The resistive elements of the motor heat the motor under the action of the current thermal effect. In the embodiment of the application, the voltage output by the power battery can be boosted and inverted and then output to the motor.

[0050] When the motor is accelerated under the action of the power battery, the motor speed reaches the second set value; due to the existence of the motor moment of inertia, the motor speed will exceed the second set value under the action of the moment of inertia. When the motor speed reaches the second set value, the motor kinetic energy is recovered to charge the power battery, and the motor speed is reduced; at this time, the motor is in the state of a generator. During the kinetic energy recovery process, the alternating current output by the motor is rectified and output to the power battery to charge the power battery; during this period, the kinetic energy of the motor is converted into electric energy in the power battery. During the kinetic energy recovery process, the speed of the motor in the state of the generator is continuously reduced; the motor and the power battery form a charging circuit, there is current passing through the charging circuit, the internal resistance of the power battery heats the power battery under the action of the current, and the internal resistance of the motor heats the motor under the action of the current. In the embodiment of the application, in order to avoid that the voltage after rectification is less than the voltage of the power battery, resulting in charging failure. The alternating current output by the motor can be boosted and rectified, and the voltage after boosting and rectifying is used to charge the power battery.

[0051] The power battery and the motor are charged and discharged with each other, the current flows through the power battery and the motor, and the internal resistance of the power battery and the internal resistance of the motor heat the power battery and the motor respectively.

[0052] In the embodiment, in the motor control system for processing the mutual charging and discharging of the power battery and the motor, the switching vector control technology can be used to control the energy exchange of the motor and the power battery. The motor switching vector refers to changing the voltage vector of the motor by controlling the state of the switch in the motor control system, and then achieving the purpose of controlling the motor speed and torque. Specifically, the time proportion of the switch is adjusted, so that the voltage vector generated by the switch is close to the required voltage vector, thereby realizing accurate control of the motor.

[0053] Referring to Fig. 2, wherein V0~V7 represent basic voltage vectors, V0 (0, 0, 0) represents that the three groups of switch tubes are all closed, and V7 (1, 1, 1) represents that the three groups of switch tubes are all turned on. During the heating process, the heating system constantly changes the state between the voltage vectors V0~V7. The heating speed of the battery and the heating efficiency and voltage utilization rate are related. Referring to Fig. 3, according to the size of the voltage utilization rate, the motor speed during the battery heating can be divided into a high working efficiency area and a low working efficiency area and an overflow area. The three areas are divided by two speeds NH and NL. When the speed is lower than NL, the voltage utilization rate is low, and the thermal efficiency is low at this time. When the speed is higher than NH, the high speed does not improve the voltage utilization rate. A second setting value NU close to NH and a first setting value ND close to NL can be set between NH and NL, and the upper and lower limits of the motor speed during heating are set to leave a reasonable threshold to ensure the efficient operation of the motor heating. The first setting value ND and the second setting value NU are determined by the researchers according to the experimental results.

[0054] The heating method provided in the application is applied to a heating system including a motor and a power battery, does not need additional heating devices, and only needs to exchange energy between the motor and the power battery. During the energy exchange process, the internal resistance of the power battery heats the power battery through the current heat effect, and the internal resistance of the motor heats the motor through the current heat effect. The scheme directly has high heating efficiency, and most of the conversion loss of electric energy and mechanical energy is used for heating the power battery and the motor. The heating system can be applied to an electric vehicle. During the heating process, if the voltage utilization rate is too low, the voltage utilization rate can be improved by increasing the magnetic flux of the permanent magnet through a reasonable id instruction value, thereby improving the heating efficiency. Similarly, the motor speed can be increased and the heating efficiency can be improved by weakening the magnetic flux of the permanent magnet through a reasonable id instruction value.

[0055] The application discloses a heating method applied to a heating system including a motor and a power battery. The heating method comprises the following steps: detecting the motor speed; when the motor speed is less than a first setting value, controlling the power battery to supply power to the motor to increase the motor speed, so as to heat the power battery by using the internal resistance of the power battery and heat the motor by using the internal resistance of the motor during the power supply process; and when the motor speed reaches a second setting value, recovering the motor kinetic energy to charge the power battery and reduce the motor speed, so as to heat the power battery by using the internal resistance of the power battery and heat the motor by using the internal resistance of the motor during the kinetic energy recovery process. The application can heat the power battery and the motor by monitoring the motor speed and controlling the power battery and the motor to constantly charge and discharge, so as to keep the motor speed in a certain fluctuation range.

[0056] In the embodiment of the present application, after the motor speed reaches the second set value, the motor kinetic energy is recovered to charge the power battery and reduce the motor speed, and after the internal resistance of the power battery is used to heat the power battery in the process of recovering the kinetic energy, the method further comprises:

[0057] In the process of recovering the kinetic energy, the step of detecting the motor speed is returned.

[0058] In the embodiment, after the motor speed is less than the first set value and the power battery supplies power to the motor to increase the motor speed, the motor speed reaches the second set value and the motor charges the power battery as a cycle. It is easy to understand that the motor speed is continuously reduced in the process of recovering the kinetic energy, and the temperature of the power battery is increased in a cycle, which may be insufficient to heat the power battery to the desired temperature. Therefore, in the process of recovering the kinetic energy, the motor speed is detected; so that when the motor speed is less than the first set value, the power battery supplies power to the motor to increase the motor speed; and the power battery heating in a new cycle is started.

[0059] Referring to FIG. 4, in the embodiment of the present application, before the step of detecting the motor speed, the method further comprises:

[0060] Step S40, detecting the temperature of the power battery;

[0061] Step S50, when the temperature of the power battery is less than a first temperature value, the step of detecting the motor speed is performed.

[0062] In the embodiment, considering the actual demand, because the air temperature affects the ion activity of the lithium battery, and further affects the endurance mileage and charge-discharge performance, the endurance mileage of the electric vehicle in a low temperature environment will be reduced to different degrees. Therefore, the scheme proposed in the present application is applied in a low temperature environment where the power battery needs to be heated; therefore, before starting the power battery heating, the temperature of the power battery can be detected to determine whether the environmental temperature meets the temperature of the scheme application.

[0063] The first temperature value can be determined by the developer according to the charge-discharge performance of the power battery at different temperatures. When the temperature of the power battery is detected to be less than the first temperature value, the step of detecting the motor speed is started; and then the motor speed is controlled to charge or discharge the power battery.

[0064] After the temperature of the power battery is detected, the method further comprises:

[0065] Step S60, when the temperature of the power battery is greater than a second temperature value, the step of detecting the motor speed is stopped.

[0066] In the embodiment, as the temperature of the power battery increases, the charging and discharging performance of the power battery is improved accordingly; when the temperature of the power battery reaches the second temperature value, it can be considered that the performance of the power battery has been freed from the influence of low temperature. At this time, the purpose of heating the power battery is achieved, and the subsequent step of heating the power battery can be stopped. It is easy to understand that after the step of detecting the temperature of the power battery is performed, the step of detecting the temperature of the power battery is performed, and then according to the temperature of the power battery, it is judged whether the step of detecting the motor speed is performed. The second temperature value is determined by the researchers.

[0067] Referring to FIG. 5, in the embodiment of the application, before the step of detecting the temperature of the power battery, the following steps are further included:

[0068] Step S70, disconnecting the power connection between the motor and the power transmission device to avoid driving the vehicle to travel when the motor rotates.

[0069] In the embodiment, the core of the motor active thermal control technology based on flywheel energy storage is to utilize the generator and motor states of the motor to enable energy to flow between the power battery and the motor, so as to heat the power battery. When the motor operates in the generator and motor states, the motor speed will change. Disconnecting the power connection between the motor and the power transmission device between the steps of detecting the temperature of the power battery can avoid driving the vehicle to travel when the motor rotates, convert the mechanical energy of the motor into the kinetic energy of the vehicle, and reduce the thermal efficiency of heating the power battery. In addition, if the motor drives the vehicle to travel when the motor is running, unstable motor speed can cause accidents of the vehicle. In an embodiment of the application, the gear of the electric vehicle can be adjusted to N gear. The power transmission device can include a gearbox.

[0070] In the embodiment of the application, the step of controlling the power battery to supply power to the motor to increase the motor speed when the motor speed is less than the first set value specifically includes:

[0071] By changing the current or voltage output by the power battery to the motor, the motor speed value is increased.

[0072] The motor input end receives alternating current, and the power battery outputs direct current; in the embodiment, the direct current output by the power battery is converted into three-phase alternating current after inversion, and the three-phase alternating current is converted into corresponding d-axis current id and q-axis current iq after Clarke transformation. The d-axis current is a current component in the same direction as the rotor magnetic field, and is mainly used for controlling the magnetic flux of the motor, i.e. the excitation current. When the d-axis current increases, the magnetic flux of the motor increases, thereby enhancing the magnetic field of the motor, and the motor speed decreases, and vice versa. The q-axis current is a current component perpendicular to the rotor magnetic field, and is mainly used for controlling the torque of the motor, i.e. the torque current. By adjusting the size of the q-axis current, the torque output of the motor can be changed, thereby realizing control of the motor speed. The d-axis current and the q-axis current received by the motor can be changed by changing the alternating current output by the power battery to the motor, thereby changing the motor speed value. In addition, the motor speed value can be increased by changing the voltage output by the power battery to the motor. The voltage of the three-phase alternating current can be converted into corresponding d-axis voltage and q-axis voltage through Clarke transformation.

[0073] By optimizing the calibration of the idiq instruction value, the heating efficiency and the heating current amplitude frequency can reach relatively optimal values, and the ideal battery heating state is: the battery heating current amplitude and frequency are preferentially ensured to be at the optimal heating value (related to the battery itself parameters), and then the motor speed during battery heating is ensured to be in the high-efficiency zone. When the motor speed decreases or increases, the high-efficiency speed zone is widened through the id instruction value respectively. When the motor speed deviates from the high-efficiency zone, the heating current frequency can be sacrificed to change the charging and discharging time, so that the motor returns to the high-efficiency zone.

[0074] In the embodiment, the waveform of the d-axis current is one of a sine wave, a triangular wave and a square wave, and / or,

[0075] The waveform of the q-axis current is one of a sine wave, a triangular wave and a square wave.

[0076] In the embodiment, the waveform of the d-axis current is consistent with the waveform of the q-axis current; when the d-axis current is a sine wave, the waveform of the q-axis current is also a sine wave.

[0077] In an embodiment of the present application, the flywheel energy storage based motor autonomous thermal control technology can be used to heat the battery and motor at low temperature, and has the advantages of fast heating speed, high heating efficiency, and small damage to the battery. The bus current fundamental wave of this heating method is a certain frequency square wave (current commutation requires a certain time during motor generation mode conversion), and compared with the d-axis current high-frequency harmonic injection heating method in the motor static state, the locked rotor heating method has the advantages of low noise and small damage to the DC end capacitor, and is more suitable for electric vehicle battery heating. The flywheel energy storage based motor autonomous thermal control technology can not only be used to heat the battery, but also can heat the motor by matching the id harmonic injection.

[0078] In an embodiment of the present application, when the motor speed reaches the second set value, the step of recovering motor kinetic energy to charge the power battery and reducing the motor speed specifically includes:

[0079] The alternating current output by the motor in the generator state is rectified to charge the power battery;

[0080] In the process of converting motor kinetic energy into electrical energy, the speed of the motor is reduced.

[0081] In this embodiment, the motor in the generator state converts the mechanical energy of the motor into electrical energy output to charge the power battery. In the process of converting motor kinetic energy into electrical energy, the speed of the motor is reduced.

[0082] In an embodiment of the present application, the heating method further includes:

[0083] The temperature rise distribution between the motor and the power battery is realized by the battery cooling liquid.

[0084] In the heating system including the motor and the power battery, the cooling liquid of the power battery can be connected with the motor through a transmission device; when the motor and the power battery are heated, the battery cooling liquid conducts the heat of the motor to the power battery, thereby improving the heating speed of the power battery. The type and flow rate of the battery cooling liquid affect the heat flow between the motor and the power battery. The transmission device can include a valve for controlling whether the battery cooling liquid can simultaneously contact the motor and the power battery to conduct heat.

[0085] In an embodiment of the present application, the heating system uses a switching vector control technology to control the motor;

[0086] The heating method further includes:

[0087] When the battery heating is the main heating demand, the time ratio of the heating system working in the zero vector state is reduced;

[0088] When the motor heating is the main heating demand, the time ratio of the heating system working in the zero vector state is increased.

[0089] In the embodiment, the heating system uses the switching vector control technology to control the motor; the heating system comprises three groups of switching tubes.

[0090] Referring to FIG. 2, V0-V7 represent basic voltage vectors, wherein V0 (0, 0, 0) represents that the switching tubes of the three groups are all closed, and V7 (1, 1, 1) represents that the switching tubes of the three groups are all turned on; V0 and V7 are called zero vector states. In the heating process, the heating system constantly changes the state between the voltage vectors V0-V7, and the time ratio of the heating system working in the zero vector state in the overall working time can be adjusted to adjust the temperature rise distribution of the motor and the power battery. When the switching vector is V1-V6, the energy between the motor and the battery is in an exchange state, and when the switching vector is V0 and V7, the motor energy circulates in the motor. Therefore, in the battery heating process, the switching tubes should be avoided from being in V0 and V7 vectors too much to reduce the time ratio of the heating system working in the zero vector state; it is easy to understand that at this time the motor works in the motor field weakening and low speed region (without power battery energy supply). In the motor heating process, the switching tubes should be kept in V0 and V7 vectors as much as possible to increase the time ratio of the heating system working in the zero vector state; it is easy to understand that at this time the motor works in the motor field strengthening and high speed region.

[0091] In addition, from the perspective of motor heat generation, iq is only used to generate heat in the stator winding when the motor rotates, and high-frequency harmonic current can be injected in the id instruction value to increase the rotor copper loss heat of the motor to improve the heating speed of the motor.

[0092] The application also provides a storage medium, wherein the storage medium stores a battery active heating program, and the battery active heating program is executed by a processor to realize the steps of the heating method.

[0093] The application also provides an electric vehicle, wherein the electric vehicle comprises the storage medium. The specific steps of the active heating method of the electric vehicle are referred to the above embodiments, and the electric vehicle adopts all the technical solutions of the above embodiments, and therefore at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described here.

[0094] The above only describes some embodiments of the application, and does not limit the patent scope of the application. Any equivalent structural transformation, direct / indirect application in other related technical fields based on the application description and the drawings all fall within the patent protection scope of the application.

Claims

1. A method of heating wherein, The heating method is applied to a heating system comprising a motor and a power battery; the heating method comprises: detecting a motor speed; when the motor speed is less than a first set value, controlling the power battery to supply power to the motor to increase the motor speed, so that the power battery is heated by the internal resistance of the power battery and the motor is heated by the internal resistance of the motor during the power supply process; when the motor speed reaches a second set value, recovering motor kinetic energy to charge the power battery and reduce the motor speed, so that the power battery is heated by the internal resistance of the power battery and the motor is heated by the internal resistance of the motor during the kinetic energy recovery process. The heating method further comprises:

2. The heating method of claim 1, wherein, during the kinetic energy recovery process, returning to the step of detecting the motor speed. Before the step of detecting the motor speed, the heating method further comprises:

3. The heating method of claim 2, wherein, detecting a temperature of the power battery; when the temperature of the power battery is less than a first temperature value, performing the step of detecting the motor speed; when the temperature of the power battery is greater than a second temperature value, stopping the step of detecting the motor speed. Before the step of detecting the temperature of the power battery, the heating method further comprises:

4. The heating method of claim 3, wherein, disconnecting the power connection between the motor and the power transmission device to avoid driving the vehicle to travel when the motor rotates. The step of controlling the power battery to supply power to the motor to increase the motor speed when the motor speed is less than a first set value specifically comprises:

5. The heating method according to any one of claims 1 to 4, wherein increasing the motor speed value by changing the current or voltage output from the power battery to the motor. The step of recovering motor kinetic energy to charge the power battery and reduce the motor speed when the motor speed reaches a second set value specifically comprises:

6. The heating method according to any one of claims 1 to 4, wherein rectifying the alternating current output from the motor in the generator state to charge the power battery; and reducing the motor speed during the conversion of motor kinetic energy into electrical energy. The heating method further comprises:

7. The heating method according to any one of claims 1 to 4, wherein distributing the temperature rise between the motor and the power battery through a battery cooling liquid. The heating system uses a switching vector control technology to control the motor.

8. The heating method according to any one of claims 1 to 4, wherein The heating method further comprises: when battery heating is the main heating requirement, reducing the proportion of time during which the heating system works in a zero vector state; when motor heating is the main heating requirement, increasing the proportion of time during which the heating system works in a zero vector state. The storage medium stores a battery active heating program, and the battery active heating program is executed by the processor to implement the steps of the heating method according to any one of claims 1 to 8.

9. A storage medium, wherein, The electric vehicle comprises the storage medium according to claim 9.

10. An electric vehicle, wherein, ​

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