Battery dynamic balancing device, control method thereof and vehicle

Abstract

The application discloses a kind of battery dynamic equalization device and its control method and vehicle, the device includes: power battery;Motor controller;Motor;Controller is connected with motor controller, controller is configured as: in first preset state, the bridge arm of motor controller is controlled, to drive motor, and first battery pack and second battery pack are alternately charged and discharged, to realize self-heating of first battery pack and second battery pack, and the absolute value of the difference of the electric capacity of first battery pack and the electric capacity of second battery pack is lower than preset threshold value.The equalization device of the application can realize the dynamic equalization of the electric quantity between first battery pack and second battery pack in the self-heating process of battery when vehicle is in driving condition, to improve the performance of battery and prolong battery life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery protection, and in particular to a battery dynamic balancing device, a control method of the battery dynamic balancing device and a vehicle. BACKGROUND

[0002] With the development and rapid popularization of electric vehicles, the power battery of the electric vehicle becomes more and more important. At present, when the power battery of the vehicle is self-heating during driving, the voltage difference between the batteries may gradually increase, thereby causing imbalance between the batteries and possibly leading to reduced battery capacity and shortened battery life. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, a first object of the present application is to provide a battery dynamic balancing device capable of achieving dynamic balancing of electric quantity between a first battery pack and a second battery pack during self-heating of the batteries when the vehicle is in a driving condition, thereby improving the performance of the batteries and prolonging the life of the batteries.

[0004] A second object of the present application is to provide a control method of the battery dynamic balancing device.

[0005] A third object of the present application is to provide a vehicle.

[0006] To achieve the above objects, a first aspect of the present application provides a battery dynamic balancing device, comprising: a power battery, the power battery comprising a first battery pack and a second battery pack connected in series, and having a first node between the first battery pack and the second battery pack; a motor controller, the first end of the motor controller being connected to the positive electrode of the first battery pack, and the second end of the motor controller being connected to the negative electrode of the second battery pack; a motor, the first end of the motor being connected to the motor controller, and the second end of the motor being connected to the first node; and a controller, the controller being connected to the motor controller, and the controller being configured to: in a first preset state, control the bridge arm of the motor controller to drive the motor, and alternately charge and discharge the first battery pack and the second battery pack to achieve self-heating of the first battery pack and the second battery pack, and to cause the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack to be lower than a preset threshold.

[0007] According to the battery dynamic balancing device provided by the embodiment of the present application, the power battery comprises a first battery pack and a second battery pack connected in series, and the first battery pack and the second battery pack have a first node therebetween; a first end of the motor controller is connected with a positive electrode of the first battery pack; a second end of the motor controller is connected with a negative electrode of the second battery pack; a first end of the motor is connected with the motor controller; a second end of the motor is connected with the first node; and the controller is connected with the motor controller, and is configured to: in a first preset state, control a bridge arm of the motor controller to drive the motor, and alternately charge and discharge the first battery pack and the second battery pack to realize self-heating of the first battery pack and the second battery pack, and to make an absolute value of a difference between an electric capacity of the first battery pack and an electric capacity of the second battery pack lower than a preset threshold. Thus, the balancing device can realize dynamic balancing of electric quantity between the first battery pack and the second battery pack in a self-heating process of the battery in a driving working condition of the vehicle, thereby improving the performance of the battery and prolonging the service life of the battery.

[0008] In addition, the battery dynamic balancing device according to the above-mentioned embodiment of the present application can further have the following additional technical features:

[0009] According to an embodiment of the present application, the motor controller comprises at least two-phase first bridge arms, a first end of each phase first bridge arm is connected with a positive electrode of the first battery pack, and a second end of each phase first bridge arm is connected with a negative electrode of the second battery pack; the motor comprises at least two-phase first inductors, a first end of each phase first inductor is connected with a corresponding first bridge arm, and a second end of each phase first inductor is connected with the first node; and the motor has an N line connected with the first node.

[0010] According to an embodiment of the present application, the controller is configured to: collect balancing battery parameters, temperature demand parameters and driving demand parameters of the power battery; obtain a target driving current according to the driving demand parameters, a target self-heating current according to the temperature demand parameters, and a target balancing current according to the balancing battery parameters; and adjust a first control signal of the motor controller according to the target driving current, the target self-heating current, the target balancing current and an actual phase current to drive the motor and perform self-heating and balancing processing on the first battery pack and the second battery pack.

[0011] According to an embodiment of the present application, the controller is configured to: obtain a torque output of the motor, a rotating speed of the motor, a voltage of the power battery and a rotor electric angle of the motor; when a driving instruction is received, obtain a target driving current according to the torque output of the motor, the rotating speed of the motor and the voltage of the power battery, and obtain a differential mode voltage of each phase bridge arm according to the target driving current, an actual phase current and the rotor electric angle of the motor.

[0012] According to one embodiment of the present application, the target drive current is a combination of a d-axis target current and a q-axis target current, the actual phase current is a combination of a d-axis actual current and a q-axis actual current, and the controller is configured to: perform closed-loop control on the d-axis target current and the d-axis actual current, and on the q-axis target current and the q-axis actual current, to obtain a d-axis target voltage and a q-axis target voltage; and obtain the differential mode voltage of each phase bridge arm according to the d-axis target voltage, the q-axis target voltage, and a rotor electrical angle of the motor.

[0013] According to one embodiment of the present application, the controller is further configured to: obtain a target heating and balancing current according to the target self-heating current and the target balancing current; obtain an actual phase current of the motor; obtain a common mode voltage according to the target heating and balancing current and the actual phase current; and adjust the first control signal of the motor controller according to the differential mode voltage of each phase bridge arm and the common mode voltage.

[0014] According to one embodiment of the present application, the controller is configured to: collect a balancing battery parameter and a temperature demand parameter of the power battery; obtain the target balancing current according to the balancing battery parameter, and obtain the target self-heating current according to the temperature demand parameter.

[0015] According to one embodiment of the present application, the controller is configured to: perform integral calculation on the balancing battery parameter to obtain the target balancing current, wherein the balancing battery parameter comprises one of a discharge capacity difference, a voltage difference, and an instantaneous power difference, and the discharge capacity difference, the voltage difference, and the instantaneous power difference represent a difference between discharge capacities, a difference between voltages, and a difference between instantaneous powers of the first battery pack and the second battery pack, respectively.

[0016] According to one embodiment of the present application, the balancing battery parameter is the discharge capacity difference, and the controller is configured to: collect a per-phase phase current of the motor; calculate an N-line current of the motor according to the per-phase phase current of the motor; and perform integral processing on the N-line current to obtain the discharge capacity difference.

[0017] According to one embodiment of the present application, the balancing battery parameter is the discharge capacity difference, and the controller is configured to: collect a bus positive electrode current and a bus negative electrode current of the power battery; perform ampere-hour integration on the bus positive electrode current of the power battery to obtain a discharge capacity of the first battery pack, and perform ampere-hour integration on the bus negative electrode current of the power battery to obtain a discharge capacity of the second battery pack; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0018] According to one embodiment of the present application, the equalization battery parameter is the discharge capacity difference; the controller is configured to: collect the bus positive electrode current of the motor controller and the bus negative electrode current of the motor controller; perform ampere-hour integration on the bus positive electrode current to obtain the discharge capacity of the first battery pack and perform ampere-hour integration on the bus negative electrode current to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0019] According to one embodiment of the present application, the equalization current parameter is the voltage difference value; the controller is configured to: collect the bus voltage of the motor controller and the voltage of the first battery pack; calculate the voltage of the second battery pack according to the bus voltage and the voltage of the first battery pack; and determine the voltage difference value according to the voltage of the first battery pack and the voltage of the second battery pack.

[0020] According to one embodiment of the present application, the equalization current parameter is the instantaneous power difference value; the controller is configured to: collect the bus positive electrode current of the power battery, the bus negative electrode current of the battery, the voltage of the first battery pack and the voltage of the second battery pack; determine the instantaneous power of the first battery pack according to the bus positive electrode current of the battery and the voltage of the first battery pack, and determine the instantaneous power of the second battery pack according to the bus negative electrode current of the battery and the voltage of the second battery pack; and determine the instantaneous power difference value according to the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

[0021] According to one embodiment of the present application, the controller is configured to: obtain the demand heating power according to the temperature demand parameter; determine the amplitude and frequency of the self-heating current of the N-wire according to the demand heating power; and determine the target heating current according to the amplitude and the frequency.

[0022] According to one embodiment of the present application, the controller is further configured to: obtain the target heating equalization current by the following formula:

[0023] In*=indc+ipk·sin(2·π·f·t)

[0024] Wherein, In* represents the target heating equalization current, indc represents the target equalization current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents the current time.

[0025] According to one embodiment of the present application, the controller is configured to: in the second preset state, detect that the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is not lower than a preset threshold, control the bridge arm of the motor controller, and perform equalization processing on the first battery pack and the second battery pack.

[0026] To achieve the above object, the second aspect of the present application provides a control method of a battery dynamic balancing device, the device comprising: a power battery, a motor controller, a motor and a controller, wherein the power battery comprises a first battery pack and a second battery pack connected in series, and the first battery pack and the second battery pack have a first node therebetween, the motor controller has a first end connected with a positive pole of the first battery pack, a second end connected with a negative pole of the second battery pack, the motor has a first end connected with the motor controller, a second end connected with the first node, and the controller is connected with the motor controller, the method is applied to the controller and comprises: in a first preset state, controlling the motor controller to drive the motor, and causing the first battery pack and the second battery pack to alternately charge and discharge to realize self-heating of the first battery pack and the second battery pack, and causing an absolute value of a difference between an electric capacity of the first battery pack and an electric capacity of the second battery pack to be lower than a preset threshold.

[0027] The control method of the battery dynamic balancing device according to the embodiment of the present application, the device comprising: a power battery, a motor controller, a motor and a controller, wherein the power battery comprises a first battery pack and a second battery pack connected in series, and the first battery pack and the second battery pack have a first node therebetween, the motor controller has a first end connected with a positive pole of the first battery pack, a second end connected with a negative pole of the second battery pack, the motor has a first end connected with the motor controller, a second end connected with the first node, and the controller is connected with the motor controller, the method is applied to the controller and comprises: in a first preset state, controlling the motor controller to drive the motor, and causing the first battery pack and the second battery pack to alternately charge and discharge to realize self-heating of the first battery pack and the second battery pack, and causing an absolute value of a difference between an electric capacity of the first battery pack and an electric capacity of the second battery pack to be lower than a preset threshold. Thus, the method can realize dynamic balancing of electric quantity between the first battery pack and the second battery pack in the self-heating process of the battery when the vehicle is in a driving working condition, thereby improving the performance of the battery and prolonging the service life of the battery.

[0028] To achieve the above object, the third aspect of the present application provides a vehicle comprising the above battery dynamic balancing device.

[0029] The vehicle according to the embodiment of the present application can realize dynamic balancing of electric quantity between the first battery pack and the second battery pack in the self-heating process of the battery when the vehicle is in a driving working condition through the above battery dynamic balancing device, thereby improving the performance of the battery and prolonging the service life of the battery.

[0030] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1Block diagram of battery dynamic balancing device according to an embodiment of the present application;

[0032] Figure 2 Circuit diagram of battery dynamic balancing device according to an embodiment of the present application;

[0033] Figure 3 Schematic diagram of realizing battery dynamic balancing in vehicle driving working condition and self-heating mode according to an embodiment of the present application;

[0034] Figure 4 Flow chart of control method of battery dynamic balancing device according to an embodiment of the present application;

[0035] Figure 5 Flow chart of control method of battery dynamic balancing device according to a specific example of the present application;

[0036] Figure 6 Block diagram of vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which the same or similar notations used throughout the drawings and the specification denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0038] During the self-heating operation of the whole vehicle battery, each battery pack is continuously charged and discharged at a high frequency. In fact, the differences in state, impedance and temperature characteristics of each battery cell, and the voltage difference between the battery packs will appear if no balancing adjustment is made, which will accelerate the unbalance between the battery packs. With the increase of the self-heating time, the voltage difference between the battery packs also gradually increases, and the battery capacity becomes more and more unbalanced (for example, two battery packs E1 and E2, one of which is fully charged and the other of which is discharged), the endurance mileage sharply decreases, and long time may lead to shortening of the battery life. Therefore, in order to solve the unbalance between the battery pack voltages during the battery self-heating process, the present application proposes a battery dynamic balancing device, which judges whether the initial electric quantity of each battery pack is balanced before the battery self-heating function is turned on in the driving working condition of the vehicle, and whether the electric quantity between each battery pack is balanced during the battery self-heating operation, so as to realize the dynamic balancing of the electric quantity between the battery packs in the case of unbalanced electric quantity between the battery packs during the battery self-heating process, thereby improving the performance of the battery and prolonging the life of the battery.

[0039] The battery dynamic balancing device, the control method of the battery dynamic balancing device and the vehicle proposed by the embodiments of the present application are described below with reference to the accompanying drawings.

[0040] Figure 1 This is a block diagram of a battery dynamic balancing device according to an embodiment of the present invention.

[0041] like Figure 1 As shown, the battery dynamic balancing device may include: a power battery 110, a motor controller 120, a motor 130, and a controller 140.

[0042] The power battery 110 includes a first battery pack E1 and a second battery pack E2 connected in series, with a first node J1 between them. A motor controller 120 has its first terminal connected to the positive terminal of the first battery pack E1 and its second terminal connected to the negative terminal of the second battery pack E2. A motor 130 has its first terminal connected to the motor controller 120 and its second terminal connected to the first node J1. A controller 140 is connected to the motor controller and is configured to: in a first preset state, control the arm of the motor controller 120 to drive the motor 130, causing the first battery pack E1 and the second battery pack E2 to alternately charge and discharge, thereby achieving self-heating of the first battery pack E1 and the second battery pack E2, and ensuring that the absolute value of the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 is lower than a preset threshold. The first preset state refers to the state where the vehicle is in driving condition, and the power battery is self-heating and balancing; the preset threshold can be determined according to actual conditions.

[0043] Furthermore, such as Figure 2 As shown, according to one embodiment of the present invention, the motor controller 120 includes at least two phase first bridge arms 121, the first end of each phase first bridge arm 121 is connected to the positive terminal of the first battery pack E1, and the second end of each phase first bridge arm 121 is connected to the negative terminal of the second battery pack E2; the motor 130 includes at least two phase first inductors 131, the first end of each phase first inductor 131 is connected to the corresponding first bridge arm 121, and the second end of each phase first inductor 131 is connected to the first node J1; the motor 130 leads out an N line, which is connected to the first node J1.

[0044] Specifically, motor 130 may include permanent magnet synchronous motors, asynchronous motors, and other types of motors. Motor 130 may be three-phase, five-phase, six-phase, nine-phase, etc. Motor 130 may include multiple sets of windings: the motor coil includes x sets of windings, where x ≥ 1 and x is an integer. Each set of windings contains at least two phase windings, and each phase winding corresponds to a set of bridge arms for control. Figure 2The motor is a three-phase motor. The two battery groups (first battery group E1 and second battery group E2) of the power battery 110 are connected in series, each battery group is connected by a plurality of battery units (or battery sections), the two battery groups contain the same battery units, the battery units of the entire power battery 110 are even, and the positive bus, the negative bus, and the battery group series connection midpoint lead-out wire are led out from the power battery 110. The positive bus and the negative bus of the power battery 110 are connected to the positive bus and the negative bus of the motor controller 120 through switches K2 and K1, respectively. The motor controller 120 includes at least one first bridge arm 121, for example, Figure 2 A, B, and C are the first bridge arm 121, which is connected to the three-phase coil (first inductor 131) of the motor 130, respectively. The neutral line (N line) of the motor 130 is connected to the switch K6, and the switch K6 is connected to the series connection midpoint J1 lead-out wire of the power battery 110. The bus capacitor C1 is connected in parallel to the positive bus and the negative bus of the motor controller 120. The positive series connection switch K5 of the DC charging and discharging port is connected to the positive bus of the motor controller 120. The positive series connection switch K4 of the DC charging and discharging port is connected to the motor lead-out neutral line N. The negative series connection switch K3 of the DC charging and discharging port is connected to the negative bus of the motor controller 120. The positive electrode of the capacitor C2 is connected to the positive electrode of the DC charging and discharging port, and the negative electrode of the capacitor C2 is connected to the negative bus of the motor controller 120. In the shutdown state, that is, the vehicle is not charging or driving, and the system is powered off, the switches K1, K2, K3, K4, K5, and K6 are all open. In the first preset state of the vehicle, that is, in any working condition of the vehicle, when the self-heating demand signal is received, the switch K6 is controlled to be closed, and the power battery 110 can be self-heated. During the self-heating process, each battery group is continuously charged and discharged. The controller 140 (not shown in the figure) can balance the first battery group E1 and the second battery group E2 by adjusting the duty cycle of each phase bridge arm of the motor controller 120. For example, when the vehicle is in the driving working condition, and the first battery group E1 has a higher capacity and the second battery group E2 has a lower capacity, the duty cycle of the upper bridge arm conduction can be controlled to be higher, so that the electric quantity of the first battery group E1 is transferred to the first inductor 130 in the motor for storage, and is discharged to the second battery group E2 through the motor lead-out N line, that is, through the alternating charging and discharging of the first battery group E1 and the second battery group E2, so that the absolute value of the difference between the capacity of the first battery group E1 and the capacity of the second battery group E2 is reduced and is lower than the preset threshold, thereby realizing the dynamic balance of the electric quantity between the first battery group and the second battery group during the battery self-heating process, improving the performance of the battery, and prolonging the service life of the battery. The duty cycle refers to the duty cycle of the upper bridge arm conduction, and the duty cycles of the upper and lower bridge arms are complementary. For example, if the upper bridge arm conduction lasts for 70% of the total time, the lower bridge arm conduction lasts for 30% of the total time, the battery group with a higher capacity is discharged more, and the battery group with a lower capacity is discharged less, and a certain dead time can be reserved according to the characteristics of the power device.

[0045] The battery dynamic balancing device of the present application is described in detail below.

[0046] According to one embodiment of the present application, the controller 140 is configured to: collect the balancing battery parameters, the temperature demand parameters and the driving demand parameters of the power battery 110; obtain the target driving current according to the driving demand parameters, the target self-heating current according to the temperature demand parameters, and the target balancing current according to the balancing battery parameters; and adjust the first control signal of the motor controller according to the target driving current, the target self-heating current, the target balancing current and the actual phase current, so as to drive the motor and perform self-heating and balancing processing on the first battery pack E1 and the second battery pack E2.

[0047] Specifically, the controller 140 is configured to collect the balancing battery parameters when the battery pack needs balancing, the temperature demand parameters of the power battery 110 during the self-heating process of the power battery, and the driving demand parameters when the vehicle is driving. After obtaining the balancing battery parameters, the temperature demand parameters and the driving demand parameters, the target driving current can be obtained according to the driving demand parameters, for example, the target driving current can be obtained according to the driving torque of the motor 130, the speed of the motor, the bus voltage, etc. The target self-heating current can be obtained according to the temperature demand parameters, for example, by using a table in which the temperature demand parameters and the target self-heating current are in one-to-one correspondence, the target self-heating current can be determined according to the temperature demand parameters, the greater the temperature demand parameters, the greater the target self-heating current; the smaller the temperature demand parameters, the smaller the target self-heating current. The target balancing current can be obtained according to the balancing battery parameters. After obtaining the target driving current, the target self-heating current and the target balancing current, the first control signal of the motor controller can be adjusted according to the target driving current, the target self-heating current, the target balancing current and the current actual phase current, for example, when the vehicle is in the driving condition and the power battery 110 is self-heating, the first battery pack E1 has a higher capacity and the second battery pack E2 has a lower capacity, the first control signal of the motor controller can be used to make the first battery pack E1 discharge more and the second battery pack E2 discharge less. Thus, the capacity of the first battery pack E1 and the second battery pack E2 can be balanced when the vehicle is in the driving condition and the power battery is self-heating.

[0048] According to one embodiment of the present application, the controller 140 is configured to: obtain the torque output of the motor 130, the speed of the motor 130, the voltage of the power battery 110 and the rotor electric angle of the motor 130; when receiving a driving instruction, obtain the target driving current according to the torque output of the motor 130, the speed of the motor 130 and the voltage of the power battery 110, and obtain the differential mode voltage of each phase bridge arm according to the target driving current, the actual phase current and the rotor electric angle of the motor 130.

[0049] Furthermore, according to one embodiment of the present invention, the target drive current is the synthesis of the d-axis target current and the q-axis target current, and the actual phase current is the synthesis of the d-axis actual current and the q-axis actual current. The controller 140 is configured to: perform closed-loop control on the d-axis target current and the d-axis actual current, as well as the q-axis target current and the q-axis actual current, to obtain the d-axis target voltage and the q-axis target voltage; and obtain the differential mode voltage of each phase arm based on the d-axis target voltage, the q-axis target voltage, and the rotor electrical angle of the motor 130.

[0050] Specifically, in the control of permanent magnet synchronous motors, in order to obtain control characteristics similar to those of a DC motor, a coordinate system is established on the motor rotor. This coordinate system rotates synchronously with the rotor. The direction of the rotor's magnetic field is taken as the d-axis, and the direction perpendicular to the rotor's magnetic field is taken as the q-axis. By transforming the mathematical model of the motor into this coordinate system, the d-axis and q-axis can be decoupled, thereby obtaining good control characteristics. That is, by performing coordinate transformation on the phase current of each phase of the motor (130), the d-axis current and q-axis current of the motor can be obtained. The d-axis current and q-axis current are used to drive the vehicle. Figure 3 As shown, the motor has p-phase currents, i1, i2 to ip. After two coordinate transformations of each phase current, the d-axis current id and q-axis current iq of the motor are obtained. The actual phase current is the synthesis of the actual d-axis current id and the actual q-axis current iq. The motor's torque output Te*, motor speed W, power battery voltage Udc, and rotor electrical angle θ are obtained. When a drive command is received, the vehicle is in drive mode, and the target drive current can be obtained based on the motor's torque output Te*, motor speed W, and power battery voltage Udc. The target drive current is the synthesis of the d-axis target current and the q-axis target current. PID closed-loop control based on the d-axis target current id* and the actual d-axis current id yields the d-axis target voltage Ud, and PID closed-loop control based on the q-axis target current iq* and the actual q-axis current iq yields the q-axis target voltage Uq. After obtaining the target voltage Ud on the d-axis and the target voltage Uq on the q-axis, the differential mode voltages U1, U2 and Up of each phase bridge arm are obtained by inverse coordinate transformation based on the target voltages Ud, Uq and the rotor electrical angle θ of the motor.

[0051] According to one embodiment of the present invention, the controller 140 is further configured to: obtain a target heating equalization current based on a target self-heating current and a target equalization current; acquire the actual phase current of the motor; obtain a common-mode voltage based on the target heating equalization current and the actual phase current; and adjust a first control signal of the motor controller based on the differential-mode voltage and the common-mode voltage of each phase arm.

[0052] Specifically, such as Figure 3As shown, after the vehicle receives the self-heating power instruction and the battery balancing instruction, the target heating balancing current in* is obtained by the instruction solving module 2 according to the target self-heating current and the target balancing current indc. In the p-phase p+1 line motor, the currents of each phase of the motor are collected to obtain p-phase currents (i1, i2…ip), and the direction of the current flowing into the motor is the positive direction, which satisfies i1+i2+…ip+in=0, wherein in is the N-line current of the motor. The current sensor can be used to collect the current of each phase, and after the current of each phase of the motor is obtained, the N-line current in of the motor can be calculated by in=-i1-i2-…-ip. According to the target heating balancing current in* and the actual phase current, the common-mode voltage is obtained, that is, after the actual N-line current in is obtained, the common-mode voltage Un of the p-phase bridge arm control is obtained by the PR closed-loop control according to the target heating balancing current in* and the actual N-line current in. According to the common-mode voltage Un and the differential-mode voltage (U1, U2…Up) of each phase bridge arm of the motor, the PWM duty ratio of each phase in the P-phase bridge arm is adjusted to adjust the first control signal of the motor controller, so that the vehicle realizes the self-heating of the power battery and the balancing of the power battery pack in the driving working condition.

[0053] According to one embodiment of the present application, the controller 140 is configured to collect the balancing battery parameters and the temperature demand parameters of the power battery 110; obtain the target balancing current according to the balancing battery parameters, and obtain the target self-heating current according to the temperature demand parameters.

[0054] Further, according to one embodiment of the present application, the controller 140 is configured to: perform integral calculation on the balancing battery parameters to obtain the target balancing current, wherein the balancing battery parameters include one of the discharge capacity difference, the voltage difference, and the instantaneous power difference, and the discharge capacity difference, the voltage difference, and the instantaneous power difference respectively represent the difference between the discharge capacity, the voltage, and the instantaneous power of the first battery pack E1 and the second battery pack E2.

[0055] Specifically, the controller 140 collects the balancing battery parameters of the power battery 110 and the demand parameters of the temperature of the power battery 110. The balancing battery parameters of the power battery 110 can include the discharge capacity difference AQ, and the target balancing current is obtained by integral calculation on the discharge capacity difference AQ. After the target balancing current is obtained, the target self-heating current can be obtained according to the demand parameters of the temperature of the power battery 110 during self-heating, for example, the higher the demand parameters of the current temperature, the greater the target self-heating current, the smaller the demand parameters of the current temperature, the smaller the target self-heating current, etc.

[0056] The equalization current parameter of the power battery 110 can also include a voltage difference ΔU, the target equalization current is obtained by integrating the voltage difference ΔU between the first battery pack E1 and the second battery pack E2, and the target self-heating current is obtained according to the demand parameter of the temperature of the power battery 110 when self-heating, for example, the higher the demand parameter of the current temperature, the greater the target self-heating current, the smaller the demand parameter of the current temperature, the smaller the target self-heating current, and the like.

[0057] The equalization current parameter of the power battery 110 can also include an instantaneous power difference ΔP, the target equalization current is obtained by integrating the instantaneous power difference ΔP between the first battery pack E1 and the second battery pack E2, and the target self-heating current is obtained according to the demand parameter of the temperature of the power battery 110 when self-heating, for example, the higher the demand parameter of the current temperature, the greater the target self-heating current, the smaller the demand parameter of the current temperature, the smaller the target self-heating current, and the like.

[0058] According to one embodiment of the present application, the equalization battery parameter is a discharge capacity difference; the controller 140 is configured to: collect each phase current of the motor 130; calculate the N-line current of the motor 130 according to each phase current of the motor 130; and obtain the discharge capacity difference by integrating the N-line current.

[0059] Specifically, the motor 130 is an M-phase N-wire motor, for example, in a six-phase seven-wire motor, the current of each phase of the motor 130 is collected, and six phase currents (ia, ib, ic, iu, iv, and iw) are obtained, and the direction of the current flowing into the motor 130 is the positive direction, and ia+ib+ic+iu+iv+iw+in=0 is satisfied, where in is the N-wire current of the motor 130. The phase current of each phase of the motor 130 is collected by the controller 140, for example, the current of the phase current ia, ib, ic, iu, iv, and iw can be collected by a current sensor, and after the phase current of each phase of the motor 130 is obtained, the N-wire current in of the motor 130 can be calculated by in=-ia-ib-ic-iu-iv-iw. After the N-wire current in of the motor 130 is obtained, the N-wire current in can be integrated to obtain the discharge capacity difference AQ between the first battery pack E1 and the second battery pack E2. Wherein, the motor control adopts phase shift control technology (sampling the trough and peak of the PWM count value of each phase arm, and the phase shift control can realize multiple level sampling of the carrier period), the MCU collects the phase current of each phase of the motor through the zero-crossing point and the period point of the carrier period of each phase arm, which is used to calculate the N-wire current of the motor, improve the sampling number of the N-wire current of the motor within a unit period, and more accurately calculate the discharge difference of the two battery packs. Through the phase shift control technology, the current ripple of the motor neutral line can be reduced, and certain EMC (Electro Magnetic Compatibility, electromagnetic compatibility) interference and NVH (noise vibration harshness, noise vibration harshness) noise can be reduced. The update period of the discharge capacity difference AQ is that the phase current of each phase of the motor and the N current of the motor are sampled according to the carrier period of each bridge arm, and the integral of the N current of the motor in a self-heating period is updated once.

[0060] According to another embodiment of the application, the balanced battery parameter is the discharge capacity difference; the controller 140 is configured to: collect the bus positive current and the bus negative current of the power battery 110; integrate the bus positive current of the power battery 110 to obtain the discharge capacity of the first battery pack E1, and integrate the bus negative current of the power battery 110 to obtain the discharge capacity of the second battery pack E2; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack E1 and the discharge capacity of the second battery pack E2.

[0061] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the bus positive current and the bus negative current of the power battery 110, and calculates the cumulative discharge capacity Q2 by integrating the bus positive current and the bus negative current of the power battery 110, that is, by integrating the bus negative current of the power battery 110, and calculates the cumulative discharge capacity Q1 by integrating the bus positive current of the power battery 110. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference AQ can be obtained according to the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. The bus positive current and the bus negative current of the power battery can be collected by the BMS (Battery Management System, battery management system), and the current hall of the bus positive and negative of the power battery pack and the voltage sampling circuit of each battery cell are directly integrated in the BMS, without the need for additional devices.

[0062] According to another embodiment of the application, the discharge capacity difference of the balanced battery parameter is balanced; the controller 140 is configured to: collect the bus positive current of the motor controller 120 and the bus negative current of the motor controller 120; integrate the bus positive current of the motor controller 120 to obtain the discharge capacity of the first battery pack E1, and integrate the bus negative current of the motor controller 120 to obtain the discharge capacity of the second battery pack E2; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack E1 and the discharge capacity of the second battery pack E2.

[0063] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the bus positive current and the bus negative current of the motor controller 120, and calculates the cumulative discharge capacity Q1 by integrating the bus positive current and the bus negative current of the motor controller 120, that is, by integrating the bus positive current of the motor controller 120, and calculates the cumulative discharge capacity Q2 by integrating the bus negative current of the motor controller 120. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference AQ can be obtained according to the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. The bus positive current and the bus negative current of the motor controller 120 can be collected by the MCU, which can avoid the switching time of the power device and interference, so that the current collection is more accurate.

[0064] According to one embodiment of the application, the balanced current parameter is the voltage difference, and the controller 140 is configured to: collect the bus voltage of the motor controller 120 and the voltage of the second battery pack E2; calculate the voltage of the first battery pack E1 according to the bus voltage and the voltage of the second battery pack E2; and determine the voltage difference according to the voltage of the first battery pack E1 and the voltage of the second battery pack E2.

[0065] Specifically, the controller 140 can collect the bus voltage of the motor controller 120 and the N-line-to-ground voltage of the motor (the voltage of the second battery pack E2), wherein the bus voltage of the motor controller 120 is the sum of the voltage of the first battery pack E1 and the voltage of the second battery pack E2. After obtaining the bus voltage of the motor controller 120 and the voltage of the second battery pack E2, the voltage of the first battery pack E1 can be calculated by subtracting the voltage of the second battery pack E2 from the bus voltage of the motor controller 120. After obtaining the voltage of the first battery pack E1 and the voltage of the second battery pack E2, the voltage difference ΔU can be determined according to the voltage of the first battery pack E1 and the voltage of the second battery pack E2.

[0066] According to an embodiment of the present application, the equalization current parameter is the instantaneous power difference; the controller 140 is configured to: collect the bus positive electrode current of the power battery 110, the bus negative electrode current of the battery, the voltage of the first battery pack E1 and the voltage of the second battery pack E2; determine the instantaneous power of the first battery pack E1 according to the bus positive electrode current of the battery and the voltage of the first battery pack E1, and determine the instantaneous power of the second battery pack according to the bus negative electrode current of the battery and the voltage of the second battery pack; determine the instantaneous power difference according to the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

[0067] Specifically, the controller 140 simultaneously collects the bus positive electrode current of the power battery 110, the bus negative electrode current of the power battery, the voltage of the first battery pack E1 and the voltage of the second battery pack E2, and determines the instantaneous power p1 of the first battery pack E1 according to the product of the voltage of the first battery pack E1 and the bus positive electrode current of the power battery 110, and determines the instantaneous power p2 of the second battery pack E2 according to the product of the voltage of the second battery pack E2 and the bus negative electrode current of the power battery. After calculating the instantaneous power of each battery pack, the instantaneous power difference Δp can be determined according to the instantaneous power p1 of the first battery pack E1 and the instantaneous power p2 of the second battery pack E2.

[0068] According to an embodiment of the present application, the controller 140 is configured to: obtain the required heating power according to the temperature requirement parameter; determine the amplitude and frequency of the N-line self-heating current according to the required heating power; and determine the target heating current according to the amplitude and frequency.

[0069] Further, according to an embodiment of the present application, the controller 140 is further configured to: obtain the target heating equalization current by the following formula:

[0070] In*=indc+ipk·sin(2·π·f·t) (1)

[0071] Wherein, In* represents the target heating equalization current, indc represents the target equalization current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents the current time.

[0072] Specifically, after obtaining the self-heating demand signal of the power battery 110, it can be determined whether the self-heating function needs to be performed according to the current temperature of the power battery 110. When the temperature of the power battery 110 is low, in order to ensure the power supply capacity of the power battery 110, the self-heating program of the battery can be entered. The demand heating power is determined according to the heating demand of the power battery 110, that is, according to the temperature demand parameter of the power battery 110 when self-heating. For example, when the current temperature of the power battery 110 is low, the demand heating power will be higher; when the current temperature of the power battery 110 is high, the demand heating power will be lower. After obtaining the demand heating power, the amplitude ipk and the frequency f of the self-heating current of the N lines can be determined according to the size of the demand heating power. After obtaining the amplitude ipk and the frequency f of the self-heating current of the N lines, the target heating current can be determined according to the amplitude ipk and the frequency f. And the target heating equalization current In* can be determined according to the target equalization current indc, the amplitude ipk and the frequency f of the target self-heating current, and the current time through the above formula (1).

[0073] It should be noted that the demand heating power corresponding to the temperature demand parameter of the power battery 110, the amplitude ipk of the target self-heating current, and the frequency f of the target self-heating current can be bench calibrated first. Generally, the table lookup or linear fitting method can be used to obtain.

[0074] According to an embodiment of the present application, the controller 140 is configured to: in the second preset state, detect that the absolute value of the difference between the electric capacity of the first battery pack E1 and the electric capacity of the second battery pack E2 is not lower than a preset threshold, and control the bridge arm of the motor controller to perform equalization processing on the first battery pack E1 and the second battery pack E2.

[0075] Specifically, when the absolute value of the difference between the electric capacity of the first battery pack E1 and the electric capacity of the second battery pack E2 is detected to be not lower than a preset threshold, it indicates that the difference between the electric capacity of the first battery pack E1 and the electric capacity of the second battery pack E2 is large at present, and the power battery 110 is not in an equalization state. That is, in the second preset state (the state in which the power battery 110 only performs electric quantity equalization), the bridge arm of the motor controller 120 can be controlled to perform equalization processing on the first battery pack E1 and the second battery pack E2, so that the absolute value of the difference between the electric capacity of the first battery pack E1 and the electric capacity of the second battery pack E2 is small. For example, when the electric capacity of the first battery pack E1 is large and the electric capacity of the second battery pack E2 is small, the first battery pack E1 can be discharged for a longer time and the second battery pack E2 can be charged for a longer time, thereby realizing the equalization processing of the electric capacity between the first battery pack E1 and the second battery pack E2.

[0076] In summary, according to the battery dynamic balancing device of the embodiment of the present application, the power battery comprises a first battery pack and a second battery pack connected in series, and a first node is arranged between the first battery pack and the second battery pack, the first end of the motor controller is connected with the positive electrode of the first battery pack, the second end of the motor controller is connected with the negative electrode of the second battery pack, the first end of the motor is connected with the motor controller, the second end of the motor is connected with the first node, the controller is connected with the motor controller, and the controller is configured to: in a first preset state, control the bridge arm of the motor controller to drive the motor, and alternately charge and discharge the first battery pack and the second battery pack to realize self-heating of the first battery pack and the second battery pack, and the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is lower than a preset threshold. Therefore, the balancing device can realize dynamic balancing of the electric capacity between the first battery pack and the second battery pack in the self-heating process of the battery in the driving working condition of the vehicle, thereby improving the performance of the battery and prolonging the service life of the battery.

[0077] Corresponding to the above embodiment, the present application also provides a control method of the battery dynamic balancing device.

[0078] As shown in Figure 4 , the control method of the battery dynamic balancing device of the embodiment of the present application comprises the following steps:

[0079] S1, in a first preset state, the motor controller is controlled, and the first battery pack and the second battery pack are alternately charged and discharged to realize self-heating of the first battery pack and the second battery pack, and the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is lower than a preset threshold.

[0080] The control method of the present application will be described below in combination with Figure 5 .

[0081] As a specific example, the control method of the battery dynamic balancing device of the present application can comprise the following steps:

[0082] S100, the MCU acquires a battery self-heating demand signal and enters a battery self-heating program.

[0083] S101, it is judged whether self-heating is needed according to the current battery temperature. If yes, step S102 is executed; if no, step S108 is executed.

[0084] S102, the switch module of the battery dynamic balancing device is controlled to be closed.

[0085] S103, the heating power needed is determined according to the battery temperature, the amplitude and frequency of the self-heating current are determined, and the initial bias current is determined according to the initial voltage or capacity of the battery pack.

[0086] S104, it is judged whether the battery active balancing command is received. If yes, step S105 is executed; if no, step S110 is executed.

[0087] S105, the motor phase current is collected and the motor neutral line current value is calculated according to the motor phase current value. The discharge capacity difference is obtained by integrating the neutral line current value in N1 self-heating periods. The new neutral line self-heating balancing current is obtained by PID calculation of the discharge capacity difference. The battery dynamic balancing control is performed according to the new neutral line self-heating balancing current. The neutral line self-heating balancing current is zero after N2 self-heating periods, and the PID integral value of the discharge capacity difference is cleared. The discharge capacity difference PID calculation is not performed during N2 self-heating periods. N1 and N2 are positive integers, and N2 is much larger than N1 (for example, N2=100N1).

[0088] S106, the target heating balancing current value and the actual phase current value are obtained, PI or PR closed-loop control is performed, and the self-heating bridge arm duty cycle is calculated.

[0089] S107, the battery self-heating program is exited.

[0090] S108, according to the battery heating requirement, the battery self-heating target current value is adjusted to zero.

[0091] S109, the switch module of the battery dynamic balancing device is controlled to be disconnected, and step S107 is entered.

[0092] S110, the self-heating dynamic balancing current is zero, the PID integral value of the battery pack dynamic voltage or the discharge capacity difference is cleared, and step S106 is entered.

[0093] It should be noted that the details of the control method of the battery dynamic balancing device of the embodiment of the application are not disclosed. Please refer to the details disclosed in the battery dynamic balancing device of the embodiment of the application. Here, it is not repeated.

[0094] According to the control method of the battery dynamic balancing device, the device comprises a power battery, a motor controller, a motor and a controller, wherein the power battery comprises a first battery pack and a second battery pack connected in series, and the first battery pack and the second battery pack have a first node therebetween; the first end of the motor controller is connected with the positive pole of the first battery pack, the second end of the motor controller is connected with the negative pole of the second battery pack, the first end of the motor is connected with the motor controller, and the second end of the motor is connected with the first node; the controller is connected with the motor controller, and the method is applied to the controller and comprises the following steps: in a first preset state, the motor controller is controlled to drive the motor, and the first battery pack and the second battery pack are alternately charged and discharged to realize self-heating of the first battery pack and the second battery pack, and the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is lower than a preset threshold. Therefore, the method can realize dynamic balancing of the electric quantity between the first battery pack and the second battery pack in the self-heating process of the battery under any working condition of the vehicle, thereby improving the performance of the battery and prolonging the service life of the battery.

[0095] Corresponding to the above-mentioned embodiments, the application further provides a vehicle.

[0096] As shown in Figure 6 , the vehicle 200 of the embodiment of the application can comprise the above-mentioned battery dynamic balancing device 100.

[0097] According to the vehicle of the embodiment of the application, by comprising the above-mentioned battery dynamic balancing device, dynamic balancing of the electric quantity between the first battery pack and the second battery pack in the self-heating process of the battery under driving working condition of the vehicle can be realized, thereby improving the performance of the battery and prolonging the service life of the battery.

[0098] It is to be appreciated that the above description and the examples that follow are intended to be illustrative only and that changes can be made to the description, either functionally or chronologically, as well as changes being made concerning the order of implementation. The logic and / or steps represented in the flow diagrams and / or described herein can be considered as a sequence of executable instructions, and can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For purposes of this specification, a "computer-readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable medium can be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus) or a propagation medium. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber (optical), and a portable compact disc read-only memory (CDROM). Note that the computer-readable medium can even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example via the optical scanner of a device or device or via an intermediary, such as a facility bureau, then compiled, interpreted, or processed in a suitable manner if necessary, and then stored in a computer storage medium.

[0099] It is to be understood that the various parts of the application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, a number of steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies known in the art, or a combination thereof, can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

[0100] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0101] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying a number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0102] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0103] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A battery dynamic equalization device, characterized by, The power battery comprises a first battery pack and a second battery pack connected in series, and has a first node between the first battery pack and the second battery pack. A motor controller is connected to a positive electrode of the first battery pack at a first end and a negative electrode of the second battery pack at a second end. A motor is connected to the motor controller at a first end and the first node at a second end. A controller is connected to the motor controller and configured to control a bridge arm of the motor controller to drive the motor and alternately charge and discharge the first battery pack and the second battery pack to realize self-heating of the first battery pack and the second battery pack and to make an absolute value of a difference between a capacity of the first battery pack and a capacity of the second battery pack lower than a preset threshold in a first preset state. The controller is further configured to: collect equalization battery parameters, temperature demand parameters and driving demand parameters of the power battery, obtain a target driving current according to the driving demand parameters, a target self-heating current according to the temperature demand parameters and a target equalization current according to the equalization battery parameters, and adjust a first control signal of the motor controller according to the target driving current, the target self-heating current, the target equalization current and an actual phase current to drive the motor and perform self-heating and equalization processing on the first battery pack and the second battery pack. The motor controller comprises at least two-phase first bridge arms, each first bridge arm is connected to a positive electrode of the first battery pack at a first end and a negative electrode of the second battery pack at a second end.

2. The battery dynamic balancing apparatus according to claim 1, characterized by, The motor comprises at least two-phase first inductors, each first inductor is connected to a corresponding first bridge arm at a first end and the first node at a second end.

3. The battery dynamic balancing apparatus according to claim 2, wherein The motor has an N line connected to the first node. The controller is configured to: obtain a torque output of the motor, a speed of the motor, a voltage of the power battery and a rotor electric angle of the motor; 4. The battery dynamic balancing apparatus according to claim 3, wherein when a driving instruction is received, obtain the target driving current according to the torque output of the motor, the speed of the motor and the voltage of the power battery, and obtain a differential mode voltage of each bridge arm according to the target driving current, the actual phase current and the rotor electric angle of the motor. The target driving current is a combination of a d-axis target current and a q-axis target current, and the actual phase current is a combination of a d-axis actual current and a q-axis actual current. The controller is configured to:

5. The battery dynamic balancing apparatus according to claim 4, wherein perform closed-loop control on the d-axis target current and the d-axis actual current, and the q-axis target current and the q-axis actual current to obtain a d-axis target voltage and a q-axis target voltage; obtain a differential mode voltage of each bridge arm according to the d-axis target voltage, the q-axis target voltage and the rotor electric angle of the motor. The controller is further configured to: obtain a target heating and equalization current according to the target self-heating current and the target equalization current. acquire an actual phase current of the motor; obtain a common-mode voltage according to the target heating equalization current and the actual phase current; adjust a first control signal of the motor controller according to a differential-mode voltage of each phase bridge arm and the common-mode voltage.

6. The battery dynamic balancing apparatus according to claim 2, wherein The controller is configured to: acquire an equalization battery parameter and a temperature demand parameter of the power battery; obtain a target equalization current according to the equalization battery parameter, and obtain a target self-heating current according to the temperature demand parameter.

7. The battery dynamic balancing apparatus according to claim 6, wherein The controller is configured to: obtain the target equalization current by integral calculation on the equalization battery parameter, wherein the equalization battery parameter comprises one of a discharge capacity difference, a voltage difference value and an instantaneous power difference value, and the discharge capacity difference, the voltage difference value and the instantaneous power difference value respectively represent a difference between discharge capacities, a difference between voltages and a difference between instantaneous powers of the first battery pack and the second battery pack.

8. The battery dynamic balancing apparatus according to claim 7, wherein The equalization battery parameter is the discharge capacity difference. The controller is configured to: acquire each phase current of the motor; and calculate an N-line current of the motor according to the each phase current of the motor; and obtain the discharge capacity difference by integral processing on the N-line current.

9. The battery dynamic balancing apparatus according to claim 7, wherein The equalization battery parameter is the discharge capacity difference. The controller is configured to: acquire a bus positive electrode current and a bus negative electrode current of the power battery; perform ampere-hour integration on the bus positive electrode current of the power battery to obtain a discharge capacity of the first battery pack, and perform ampere-hour integration on the bus negative electrode current of the power battery to obtain a discharge capacity of the second battery pack; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

10. The battery dynamic balancing apparatus of claim 7, wherein, The equalization battery parameter is the discharge capacity difference. The controller is configured to: acquire a bus positive electrode current of the motor controller and a bus negative electrode current of the motor controller; perform ampere-hour integration on the bus positive electrode current to obtain a discharge capacity of the first battery pack, and perform ampere-hour integration on the bus negative electrode current to obtain a discharge capacity of the second battery pack; and obtain the discharge capacity difference according to the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

11. The battery dynamic balancing apparatus of claim 7, wherein, The equalization battery parameter is the voltage difference value. The controller is configured to: acquire a bus voltage of the motor controller and a voltage of the second battery pack; calculate a voltage of the first battery pack according to the bus voltage and the voltage of the second battery pack; and determine the voltage difference value according to the voltage of the first battery pack and the voltage of the second battery pack.

12. The battery dynamic balancing apparatus of claim 7, wherein, The equalization battery parameter is the instantaneous power difference value. The controller is configured to: acquire a bus positive electrode current, a bus negative electrode current, a voltage of the first battery pack and a voltage of the second battery pack of the power battery; determine an instantaneous power of the first battery pack according to the bus positive electrode current and the voltage of the first battery pack, and determine an instantaneous power of the second battery pack according to the bus negative electrode current and the voltage of the second battery pack; and determine the instantaneous power difference value according to the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

13. The battery dynamic balancing apparatus of claim 6, wherein, The controller is configured to obtain a demand heating power according to the temperature demand parameter, determine the amplitude and frequency of the self-heating current of the N lines according to the demand heating power, and determine the target self-heating current according to the amplitude and frequency.

14. The battery dynamic balancing apparatus of claim 13, wherein, The controller is further configured to obtain a target heating balancing current through the following formula: wherein, denotes the target heating equalization current, denotes the target equalization current, denotes the amplitude of the target self-heating current, denotes the frequency of the target self-heating current, denotes time.

15. The battery dynamic balancing apparatus of claim 1, wherein, The controller is configured to, in a second preset state, detect that the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is not lower than the preset threshold, control the bridge arm of the motor controller, and perform balancing processing on the first battery pack and the second battery pack.

16. A control method of a battery dynamic equalization device, characterized by, The battery dynamic balancing device comprises a power battery, a motor controller, a motor, and a controller, wherein the power battery comprises a first battery pack and a second battery pack connected in series, and has a first node between the first battery pack and the second battery pack; the first end of the motor controller is connected with the positive electrode of the first battery pack, the second end of the motor controller is connected with the negative electrode of the second battery pack, the first end of the motor is connected with the motor controller, and the second end of the motor is connected with the first node; the controller is connected with the motor controller, and the method is applied to the controller and comprises: In a first preset state, the motor controller is controlled to drive the motor, and the first battery pack and the second battery pack are alternately charged and discharged to realize self-heating of the first battery pack and the second battery pack, and the absolute value of the difference between the electric capacity of the first battery pack and the electric capacity of the second battery pack is lower than a preset threshold; The balancing battery parameter, temperature demand parameter, and driving demand parameter of the power battery are collected; a target driving current is obtained according to the driving demand parameter, a target self-heating current is obtained according to the temperature demand parameter, and a target balancing current is obtained according to the balancing battery parameter; the first control signal of the motor controller is adjusted according to the target driving current, the target self-heating current, the target balancing current, and the actual phase current to drive the motor, and the first battery pack and the second battery pack are self-heated and balanced.

17. A vehicle characterized by comprising: The battery dynamic balancing device comprises a power battery, a motor controller, a motor, and a controller, wherein the power battery comprises a first battery pack and a second battery pack connected in series, and has a first node between the first battery pack and the second battery pack; the first end of the motor controller is connected with the positive electrode of the first battery pack, the second end of the motor controller is connected with the negative electrode of the second battery pack, the first end of the motor is connected with the motor controller, and the second end of the motor is connected with the first node; the controller is connected with the motor controller, and the method is applied to the controller and comprises:

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