Battery dynamic equalization device, control method thereof, and vehicle

Abstract

The present invention discloses a battery dynamic balancing device, a control method thereof, and a vehicle. The device includes: a power battery; a motor controller; a DC charge / discharge port; and a controller connected to the motor controller. The controller is configured to: in a first preset state, charge the power battery via the DC charge / discharge port and control a bridge arm of the motor controller to cause a first battery pack and a second battery pack to alternately charge and discharge, thereby achieving self-heating of the first and second battery packs and causing the absolute value of the difference between the capacitance of the first and second battery packs to fall below a preset threshold. The balancing device of the present invention can achieve dynamic balancing of the charge between the first and second battery packs during the self-heating process while the power battery is charging, thereby improving battery performance and extending battery life.

Description

Technical Field

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

[0002] With the rapid development and adoption of electric vehicles, charging technology for electric vehicle power batteries has become increasingly important. This technology needs to meet the needs of diverse users and be adaptable and compatible with different power batteries and charging stations. A battery pack typically consists of multiple battery cells connected in series. Differences in charge state, impedance, and temperature characteristics between each cell can cause imbalances between the cells. This imbalance reduces the capacity and lifespan of the entire battery pack. For battery packs containing multiple cells, the state of each cell may vary due to differences in battery aging and temperature. Currently, when a vehicle is charging, the voltage difference between the cells can gradually increase, leading to imbalances and potentially shortening the battery lifespan. Summary of the Invention

[0003] The present invention aims to at least partially address one of the technical problems in the related art. To this end, the first object of the present invention is to provide a battery dynamic balancing device that can dynamically balance the charge between a first battery pack and a second battery pack during the self-heating process of a power battery during charging, thereby improving battery performance and extending battery life.

[0004] A second objective of the present invention is to provide a control method for a battery dynamic balancing device.

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

[0006] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a battery dynamic balancing device, comprising: a power battery, the power battery comprising a first battery group and a second battery group connected in series, and a first node being provided between the first battery group and the second battery group; a motor controller, the first end of the motor controller being connected to the positive pole of the first battery group, and the second end of the motor controller being connected to the negative pole of the second battery group; a DC charge and discharge port, the positive pole of the DC charge and discharge port being connected to the first bus terminal of the motor controller, and the negative pole of the DC charge and discharge port being connected to the second bus terminal of the motor controller; a controller, the controller being connected to the motor controller, and the controller being configured to: in a first preset state, charge the power battery through the DC charge and discharge port, and control the bridge arm of the motor controller, causing the first battery group and the second battery group to be alternately charged and discharged, so as to achieve self-heating of the first battery group and the second battery group, and causing the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold.

[0007] According to an embodiment of the present invention, a battery dynamic balancing device includes a power battery including a first battery group and a second battery group connected in series, with a first node between the first battery group and the second battery group, a first terminal of a motor controller connected to the positive electrode of the first battery group, a second terminal of the motor controller connected to the negative electrode of the second battery group, a positive electrode of a DC charge / discharge port connected to a first bus terminal of the motor controller, a negative electrode of the DC charge / discharge port connected to a second bus terminal of the motor controller, and a controller connected to the motor controller. The controller is configured to: in a first preset state, charge the power battery through the DC charge / discharge port, and control the bridge arm of the motor controller to cause the first battery group and the second battery group to charge and discharge alternately, so as to achieve self-heating of the first battery group and the second battery group, and cause the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold. Thus, the balancing device can achieve dynamic balancing of the charge between the first battery group and the second battery group during the self-heating process when the power battery is charging, thereby improving the battery performance and extending the battery life.

[0008] In addition, the battery dynamic balancing device according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the battery dynamic balancing device also includes a motor, and the motor controller includes at least two-phase first bridge arms, the first end of each phase first bridge arm is connected to the positive electrode of the first battery pack, and the second end of each phase first bridge arm is connected to the negative electrode of the second battery pack; the motor includes at least two-phase first inductors, the first end of each phase first inductor is connected to the corresponding first bridge arm, and the second end of each phase first inductor is connected to the first node; the motor leads out an N line, and the N line is connected to the first node.

[0010] According to one embodiment of the present invention, the battery dynamic balancing device further includes: a DC charge and discharge port, wherein the positive pole of the DC charge and discharge port is connected to the N line, and the negative pole of the DC charge and discharge port is connected to the second bus terminal of the motor controller; the controller is configured to: in a second preset state, control the bridge arm of the motor controller to boost and charge the power battery.

[0011] According to one embodiment of the present invention, the controller is configured to: collect the balancing battery parameters and temperature requirement parameters of the power battery; obtain the target balancing current according to the balancing battery parameters, and obtain the target self-heating current according to the temperature requirement parameters, and adjust the first control signal of the motor controller according to the target balancing current, the target self-heating current and the actual phase current of the motor to perform self-heating and balancing processing on the first battery group and the second battery group.

[0012] According to one embodiment of the present invention, the controller is configured to: integrate and calculate the balancing battery parameters to obtain the target balancing current, wherein the balancing battery parameters include: one of a discharge capacity difference, a voltage difference, and an instantaneous power difference, wherein the discharge capacity difference, the voltage difference, and the instantaneous power difference respectively represent the difference in discharge capacity, voltage, and instantaneous power between the first battery group and the second battery group.

[0013] According to one embodiment of the present invention, the balancing battery parameter is the discharge capacity difference; the controller is configured to: collect the phase current of each phase of the motor; calculate the N-line current of the motor based on the phase current of each phase of the motor; and integrate the N-line current to obtain the discharge capacity difference.

[0014] According to one embodiment of the present invention, the balancing battery parameter is a discharge capacity difference; the controller is configured to: collect the bus positive electrode current and the bus negative electrode current of the power battery; perform ampere-hour integration on the bus positive electrode current of the power battery to obtain the discharge capacity of the first battery group, and perform ampere-hour integration on the bus negative electrode current of the power battery to obtain the discharge capacity of the second battery group; obtain the discharge capacity difference based on the discharge capacity of the first battery group and the discharge capacity of the second battery group.

[0015] According to one embodiment of the present invention, the balancing battery parameter is a discharge capacity difference; the controller is configured to: collect the bus positive current of the motor controller and the bus negative current of the motor controller; perform ampere-hour integration on the bus positive current to obtain the discharge capacity of the first battery group, and perform ampere-hour integration on the bus negative current to obtain the discharge capacity of the second battery group; obtain the discharge capacity difference based on the discharge capacity of the first battery group and the discharge capacity of the second battery group.

[0016] According to one embodiment of the present invention, the balancing current parameter is a voltage difference; the controller is configured to: collect the bus voltage of the motor controller and the voltage of the second battery group; calculate the voltage of the first battery group based on the bus voltage and the voltage of the second battery group; determine the voltage difference based on the voltage of the first battery group and the voltage of the second battery group.

[0017] According to one embodiment of the present invention, the balancing current parameter is an instantaneous power difference; the controller is configured to: collect the bus positive current, bus negative current, voltage of the first battery group and voltage of the second battery group of the power battery; determine the instantaneous power of the first battery group based on the bus positive current and the voltage of the first battery group, and determine the instantaneous power of the second battery group based on the bus negative current and the voltage of the second battery group; determine the instantaneous power difference based on the instantaneous power of the first battery group and the instantaneous power of the second battery group.

[0018] According to one embodiment of the present invention, the controller is configured to: obtain the required heating power according to the temperature requirement parameter; determine the amplitude and frequency of the self-heating current of the N line according to the required heating power; and determine the target self-heating current according to the amplitude and frequency.

[0019] According to one embodiment of the present invention, the controller is further configured to obtain the target heating balancing current by the following formula:

[0020] In*=indc+ipk·sin(2·π·f·t)

[0021] Wherein, In* represents the target heating balancing current, indc represents the target balancing current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents time.

[0022] According to one embodiment of the present invention, the controller is further configured to: obtain the actual phase current of the motor; obtain the common mode voltage according to the target heating balancing current and the actual phase current; and adjust the first control signal of the motor controller according to the common mode voltage.

[0023] According to one embodiment of the present invention, the controller is configured to: in a third preset state, detect that the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group is not less than a preset threshold, control the bridge arm of the motor controller, and balance the first battery group and the second battery group.

[0024] To achieve the above-mentioned objectives, an embodiment of the second aspect of the present invention proposes a control method for a battery dynamic balancing device, the device including: a power battery, a motor controller, a DC charge and discharge port, and a controller, wherein the power battery includes a first battery group and a second battery group connected in series, and there is a first node between the first battery group and the second battery group, the first end of the motor controller is connected to the positive pole of the first battery group, the second end of the motor controller is connected to the negative pole of the second battery group, the positive pole of the DC charge and discharge port is connected to the first bus terminal of the motor controller, the negative pole of the DC charge and discharge port is connected to the second bus terminal of the motor controller, and the controller is connected to the motor controller. The method is applied to the controller, including: in a first preset state, charging the power battery through the DC charge and discharge port, and controlling the bridge arm of the motor controller to cause the first battery group and the second battery group to charge and discharge alternately to achieve self-heating of the first battery group and the second battery group, and causing the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold.

[0025] According to an embodiment of the present invention, a control method for a battery dynamic balancing device includes: a power battery, a motor controller, a DC charge / discharge port, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between the first battery pack and the second battery pack. A first terminal of the motor controller is connected to the positive electrode of the first battery pack, a second terminal of the motor controller is connected to the negative electrode of the second battery pack, a positive electrode of the DC charge / discharge port is connected to a first bus terminal of the motor controller, a negative electrode of the DC charge / discharge port is connected to a second bus terminal of the motor controller, and the controller is connected to the motor controller. The method is applied to the controller and includes: in a first preset state, charging the power battery through the DC charge / discharge port, and controlling a bridge arm of the motor controller to cause the first battery pack and the second battery pack to alternately charge and discharge, thereby achieving self-heating of the first battery pack and the second battery pack, and causing the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold. As a result, the method can achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the self-heating process when the power battery is charging, thereby improving battery performance and extending battery life.

[0026] To achieve the above-mentioned object, a third embodiment of the present invention provides a vehicle including the above-mentioned battery dynamic balancing device.

[0027] According to the vehicle of the embodiment of the present invention, the above-mentioned battery dynamic balancing device can achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the self-heating process when the power battery is charging, thereby improving battery performance and extending battery life.

[0028] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a block diagram of a battery dynamic balancing device according to an embodiment of the present invention;

[0030] Figure 2 2. A circuit diagram of a dynamic battery balancing device according to an embodiment of the present invention;

[0031] Figure 3 is a flow chart of a control method of a battery dynamic balancing device according to an embodiment of the present invention;

[0032] Figure 4 This is a flow chart of a control method for a battery dynamic balancing device according to a specific example of the present invention;

[0033] Figure 5 FIG. 4 is a block diagram of a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent 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 be used to explain the present invention, and are not to be construed as limiting the present invention.

[0035] During the self-heating operation of the vehicle battery, each battery pack is constantly charging and discharging, and the frequency of charging and discharging is relatively high. In fact, each battery cell has differences in state, impedance, and temperature characteristics. Once the voltage difference between the battery packs appears, if no equalization adjustment is performed, the imbalance between the battery packs will be accelerated. As the self-heating time increases, the voltage difference between the battery packs gradually increases, and the battery capacity will become more and more unbalanced (such as two battery packs E1 and E2, one of which is fully charged and the other is feeding), and the cruising range will drop sharply. If this continues for a long time, the battery life may be shortened. Therefore, in order to solve the imbalance between the battery pack voltages during the battery self-heating process, the present invention proposes a battery dynamic balancing device. When the battery is charging, before the battery self-heating function is turned on, it determines whether the initial charge of each battery pack is balanced, as well as the imbalance between each battery pack during the battery self-heating operation, so that the charge between the battery packs can be dynamically balanced when the charge between the battery packs is unbalanced, thereby improving the battery performance and extending the battery life.

[0036] The following describes a battery dynamic balancing device, a control method for a battery dynamic balancing device, and a vehicle according to embodiments of the present invention with reference to the accompanying drawings.

[0037] Figure 1 FIG. 4 is a block diagram of a battery dynamic balancing device according to an embodiment of the present invention.

[0038] like Figure 1 As shown, the battery dynamic balancing device may include: a power battery 110 , a motor controller 120 , a DC charge and discharge port 130 and a controller 140 .

[0039] The power battery 110 includes a first battery pack E1 and a second battery pack E2 connected in series, with a first node J1 defined between the first battery pack E1 and the second battery pack E2. A first terminal of the motor controller 120 is connected to the positive electrode of the first battery pack E1, and a second terminal of the motor controller 120 is connected to the negative electrode of the second battery pack E2. A positive terminal of the DC charging / discharging port 130 is connected to a first bus terminal of the motor controller 120, and a negative terminal of the DC charging / discharging port 130 is connected to a second bus terminal of the motor controller 120. A controller 140 is connected to the motor controller 120 and is configured to: in a first preset state, charge the power battery 110 via the DC charging / discharging port 130 and control the bridge arm of the motor controller 120 to alternately charge and discharge the first battery pack E1 and the second battery pack E2, 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 in capacitance between the first battery pack E1 and the second battery pack E2 is below a preset threshold. The first preset state is a state in which the power battery is self-heating and balancing when the power battery is being charged, and the preset threshold value may be determined according to actual conditions.

[0040] Furthermore, if Figure 2 As shown, according to one embodiment of the present invention, the battery dynamic balancing device also includes a motor 150, and 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 electrode of the first battery pack E1, and the second end of each phase first bridge arm 121 is connected to the negative electrode of the second battery pack E2; the motor 150 includes at least two-phase first inductors 151, the first end of each phase first inductor 151 is connected to the corresponding first bridge arm 121, and the second end of each phase first inductor 151 is connected to the first node J1; the motor 150 leads to an N line, and the N line is connected to the first node J1.

[0041] Specifically, the motor 150 may include a permanent magnet synchronous motor, an asynchronous motor, or other types of motors. The motor 150 may be three-phase, five-phase, six-phase, nine-phase, etc., wherein the motor 150 may include multiple sets of windings: the motor coil includes x sets of windings, wherein x ≥ 1, and x is an integer, each set of windings includes at least two-phase windings, and each phase winding corresponds to a set of bridge arms for control. Figure 2The shown set of windings is illustrated by taking a three-phase motor as an example. The two battery groups (the first battery group E1 and the second battery group E2) of the power battery 110 are first connected in series. Each battery group consists of a plurality of battery cells (or battery sections) connected in series. The two battery groups contain the same battery cells. The battery cells of the entire power battery 110 are an even number. The positive bus, the negative bus, and the battery group series midpoint lead-out line are drawn 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 phase first bridge arm 121, for example, Figure 2A, B, and C are the first bridge arms 121, which are respectively connected to the three-phase coils (first inductor 151) of the motor 150. The neutral line (N line) of the motor 150 is connected to the switch K6, and the switch K6 is connected to the lead line of the series midpoint J1 of the power battery 110. The bus capacitor C1 is connected in parallel to the positive and negative busbars of the motor controller 120. The positive pole of the DC charge and discharge port 130 is connected to the first bus terminal of the motor controller 120. The series switch K5 is connected to the positive pole of the motor controller 120 busbar. The positive pole of the DC charge and discharge port 130 is connected in series with the switch K4 connected to the neutral line N of the motor 150. The negative pole of the DC charge and discharge port 130 is connected to the second bus terminal of the motor controller 120. The series switch K3 is connected to the negative pole of the motor controller 120 busbar. The positive pole of the capacitor C2 is connected to the positive pole of the DC charge and discharge port 130, and the negative pole of the capacitor C2 is connected to the negative pole of the motor controller 120 busbar. In the shutdown state, that is, the vehicle is not charging or driving, and the system is powered off, switches K1, K2, K3, K4, K5, and K6 are all in the disconnected state. When the vehicle is in the first preset state, that is, the vehicle is in the charging condition, switches K1, K2, K3, K4, and K5 are controlled to be closed, and the power battery 110 is charged through the DC charge and discharge port 130. When a self-heating request signal is received, switch K6 is controlled to be closed, and the power battery 110 can be self-heated. During the self-heating process, each battery pack is continuously charged and discharged, and the controller 140 (not shown in the figure) can balance the first battery pack E1 and the second battery pack E2 by adjusting the duty cycle of each phase bridge arm of the control motor controller 120. For example, when the vehicle is in a charging condition and the power battery 110 is self-heating, when the capacity of the first battery group E1 is higher and the capacity of the second battery group E2 is lower, the duty cycle of the upper bridge arm can be controlled to be higher, so that the power of the first battery group E1 is transferred to the first inductor 151 in the motor 150 for storage, and discharged to the second battery group E2 through the N line led out from the motor 150, that is, through the alternating charge and discharge of the first battery group E1 and the second battery group E2, the self-heating of the first battery group E1 and the second battery group E2 is achieved, and 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 to below the preset threshold, so that the dynamic balance of the power between the first battery group E1 and the second battery group during the battery self-heating process when the power battery is charging can be achieved, thereby improving the battery performance and extending the battery life. Among them, the duty cycle refers to the duty cycle of the upper bridge arm, and the duty cycles of the upper and lower bridge arms are complementary. For example, the upper bridge arm is on for 70% of the total conduction time, and the lower bridge arm is on for 30%. This allows battery packs with high capacity to discharge more and battery packs with low capacity to discharge less, and a certain dead time can be retained according to the characteristics of the power device.

[0042] The battery dynamic balancing device of the present invention is described in detail below.

[0043] According to one embodiment of the present invention, Figure 2 As shown, the battery dynamic balancing device also includes: a DC charge and discharge port 130, the positive pole of the DC charge and discharge port 130 is connected to the N line, and the negative pole of the DC charge and discharge port 130 is connected to the second bus terminal of the motor controller 120; the controller 140 is configured to: in the second preset state, control the bridge arm of the motor controller to boost and charge the power battery.

[0044] Specifically, the positive electrode of the DC charge and discharge port 130 is connected to the N line through the switch K4, and the negative electrode is connected to the second bus terminal of the motor controller 120 through the switch K3. In the second preset state, that is, when the power battery 110 needs to be boosted and charged, the switches K3 and K4 can be controlled to open, and the bridge arms of the motor controller 120 can be controlled. For example, the conduction time of the first bridge arm 121 can be controlled to increase, and a higher amount of electricity can be obtained in the first inductor 151, which flows into the power battery 110 through the N line to boost and charge the power battery, thereby achieving the purpose of fast charging of the power battery 110.

[0045] According to one embodiment of the present invention, the controller 140 is configured to: collect the balancing battery parameters and temperature requirement parameters of the power battery 110; obtain the target balancing current based on the balancing battery parameters, and obtain the target self-heating current based on the temperature requirement parameters, and adjust the first control signal of the motor controller 120 based on the target balancing current, the target self-heating current and the actual phase current of the motor to perform self-heating and balancing processing on the first battery group E1 and the second battery group E2.

[0046] According to one embodiment of the present invention, the controller 140 is configured to: integrate and calculate the balancing battery parameters to obtain the target balancing current, wherein the balancing battery parameters include: one of a discharge capacity difference, a voltage difference, and an instantaneous power difference, wherein the discharge capacity difference, the voltage difference, and the instantaneous power difference respectively represent the difference in discharge capacity, voltage, and instantaneous power between the first battery group and the second battery group.

[0047] Specifically, the controller 140 collects the balancing battery parameters of the power battery 110 and the required temperature parameters of the power battery 110. The balancing battery parameters of the power battery 110 may include a discharge capacity difference ΔQ. The discharge capacity difference ΔQ is integrated to calculate a target balancing current. After obtaining the target balancing current, the target self-heating current can be obtained based on the required temperature parameters for the self-heating of the power battery 110. For example, a table lookup method can be used, in which the temperature requirement parameters in the table correspond one-to-one with the target self-heating current. The target self-heating current can be determined based on the temperature requirement parameters. The larger the temperature requirement parameters, the larger the target self-heating current; the smaller the temperature requirement parameters, the smaller the target self-heating current. After obtaining the target balancing current and target self-heating current, the first control signal for controlling the motor controller 120 can be adjusted based on the target balancing current, the target self-heating current, and the actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing of the first battery pack E1 and the second battery pack E2, thereby achieving self-heating and active balancing functions between the first battery pack E1 and the second battery pack E2.

[0048] The balancing current parameters of the power battery 110 may also include a voltage difference ΔU. The target balancing current is obtained by integrating the voltage difference ΔU between the first battery pack E1 and the second battery pack E2. The target self-heating current is also obtained based on the temperature requirement parameter for the self-heating of the power battery 110. For example, the higher the current temperature requirement parameter, the greater the target self-heating current; the lower the current temperature requirement parameter, the lower the target self-heating current. After obtaining the target balancing current and target self-heating current, the first control signal for controlling the motor controller 120 can be adjusted based on the target balancing current, the target self-heating current, and the actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing of the first battery pack E1 and the second battery pack E2, thereby achieving self-heating and active balancing functions between the first battery pack E1 and the second battery pack E2.

[0049] The balancing current parameters of the power battery 110 may also include an instantaneous power difference ΔP. The target balancing current is obtained by integrating the instantaneous power difference ΔP between the first battery pack E1 and the second battery pack E2. The target self-heating current is also obtained based on the temperature requirement parameter for the self-heating of the power battery 110. For example, the higher the current temperature requirement parameter, the greater the target self-heating current; the lower the current temperature requirement parameter, the lower the target self-heating current. After obtaining the target balancing current and target self-heating current, the first control signal for controlling the motor controller 120 can be adjusted based on the target balancing current, the target self-heating current, and the actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing of the first battery pack E1 and the second battery pack E2, thereby achieving self-heating and active balancing functions between the first battery pack E1 and the second battery pack E2.

[0050] According to one embodiment of the present invention, the balancing battery parameter is the discharge capacity difference; the controller 140 is configured to: collect the phase current of each phase of the motor; calculate the N line current of the motor based on the phase current of each phase of the motor; and integrate the N line current to obtain the discharge capacity difference.

[0051] Specifically, the motor is an M-phase N-wire motor. For example, in a six-phase seven-wire motor, the current of each phase of the motor is collected to obtain six phase currents (ia, ib, ic, iu, iv, and iw). The direction of the current flowing into the motor 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. The phase current of each phase of the motor is collected by the controller 140. For example, the current magnitude of the phase currents ia, ib, ic, iu, iv, and iw can be collected by a current sensor. After obtaining the phase current of each phase of the motor, the N-wire current in of the motor can be calculated by in=-ia-ib-ic-iu-iv-iw. After obtaining the N-wire current in of the motor, the N-wire current in can be integrated to obtain the discharge capacity difference ΔQ between the first battery pack E1 and the second battery pack E2. Among them, the motor control adopts phase-shift control technology (sampling the troughs and peaks of the PWM count value of each phase bridge arm, and phase-shift control can achieve sampling at multiple levels of the carrier cycle). The MCU simultaneously collects the phase current of each phase of the motor through the zero point or cycle point of the carrier cycle of each phase bridge arm, which is used to calculate the N-line current of the motor, increase the number of samples of the motor N-line current per unit cycle, and more accurately calculate the discharge difference between the two battery packs. The phase-shift control technology can reduce the current ripple of the neutral line of the motor, reduce certain EMC (Electro Magnetic Compatibility) interference and NVH (noise vibration harshness) noise. The update cycle of the discharge capacity difference ΔQ is based on the carrier cycle of each bridge arm, and the phase current of each phase of the motor and the N current of the motor are sampled at the same time, and the integral of the motor N current within a self-heating cycle is calculated and updated once.

[0052] According to one embodiment of the present invention, the balancing battery parameter is the discharge capacity difference; the controller 140 is configured to: collect the bus positive electrode current and the bus negative electrode current of the power battery 110; perform ampere-hour integration on the bus positive electrode current of the power battery 110 to obtain the discharge capacity of the first battery group E1, and perform ampere-hour integration on the bus negative electrode current of the power battery 110 to obtain the discharge capacity of the second battery group E2; obtain the discharge capacity difference based on the discharge capacity of the first battery group E1 and the discharge capacity of the second battery group E2.

[0053] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the busbar positive and negative currents of the power battery 110 and integrates the busbar positive and negative currents of the power battery 110 by ampere-hour integration. Specifically, the controller 140 calculates the cumulative discharge capacity Q2 by integrating the busbar negative current of the power battery 110 by ampere-hour integration, and calculates the cumulative discharge capacity Q1 by integrating the busbar positive current of the power battery 110 by ampere-hour integration. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference ΔQ can be obtained based on the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. The busbar positive and negative currents of the power battery can be collected by the BMS (Battery Management System). The BMS directly integrates the current Hall sensors of the power battery pack's busbar positive and negative poles and the voltage sampling circuit of each battery cell, eliminating the need for additional components.

[0054] According to one embodiment of the present invention, the balancing battery parameter is the discharge capacity difference; 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; perform ampere-hour integration on the bus positive current to obtain the discharge capacity of the first battery group E1, and perform ampere-hour integration on the bus negative current to obtain the discharge capacity of the second battery group E2; obtain the discharge capacity difference based on the discharge capacity of the first battery group E1 and the discharge capacity of the second battery group E2.

[0055] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the bus positive and bus negative currents of the motor controller 120, and calculates the cumulative discharge capacity Q1 by integrating the bus positive and bus negative currents of the motor controller 120 by ampere-hour, that is, by integrating the bus positive current of the motor controller 120 by ampere-hour, and calculating the cumulative discharge capacity Q2 by integrating the bus negative current of the motor controller 120 by ampere-hour. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference ΔQ can be obtained based on the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. Among them, the bus positive current of the motor controller 120 and the bus negative current of the motor controller 120 can be collected by the MCU, which can avoid the switching moments of the power devices and avoid interference, making the current collection more accurate.

[0056] According to one embodiment of the present invention, the balancing current parameter is a voltage difference; the controller 140 is configured to: collect the bus voltage of the motor controller 120 and the voltage of the second battery group E2; calculate the voltage of the first battery group E1 based on the bus voltage and the voltage of the second battery group E2; determine the voltage difference based on the voltage of the first battery group E1 and the voltage of the second battery group E2.

[0057] Specifically, the controller 140 can collect the bus voltage of the motor controller 120 and the N-line ground voltage of the motor (the voltage of the second battery pack E2), where 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 voltage of the bus 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 based on the voltage of the first battery pack E1 and the voltage of the second battery pack E2.

[0058] According to one embodiment of the present invention, the balancing current parameter is the instantaneous power difference; the controller 140 is configured to: collect the bus positive current, the bus negative current, the voltage of the first battery group E1 and the voltage of the second battery group E2 of the power battery 110; determine the instantaneous power of the first battery group E1 based on the bus positive current and the voltage of the first battery group E1, and determine the instantaneous power of the second battery group E2 based on the bus negative current and the voltage of the second battery group E2; determine the instantaneous power difference based on the instantaneous power of the first battery group E1 and the instantaneous power of the second battery group E2.

[0059] Specifically, the controller 140 simultaneously collects the bus positive current of the power battery 110, the bus negative current of the power battery, the voltage of the first battery group E1 and the voltage of the second battery group E2. The instantaneous power p1 of the first battery group E1 can be determined according to the product of the voltage of the first battery group E1 and the bus positive current of the power battery 110. The instantaneous power p2 of the second battery group E2 can be determined according to the product of the voltage of the second battery group E2 and the bus negative current of the power battery. After calculating the instantaneous power of each battery group, the instantaneous power difference Δp can be determined according to the instantaneous power p1 of the first battery group E1 and the instantaneous power p2 of the second battery group E2.

[0060] According to one embodiment of the present invention, 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.

[0061] Furthermore, according to an embodiment of the present invention, the controller 140 is further configured to obtain the target heating balancing current by the following formula:

[0062] In*=indc+ipk·sin(2·π·f·t) (1)

[0063] Where, In* represents the target heating balancing current, indc represents the target balancing 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.

[0064] Specifically, after obtaining the power battery 110 self-heating demand signal, the need for self-heating can be determined based on the current temperature of the power battery 110. When the power battery 110 temperature is relatively low, in order to ensure the power supply capacity of the power battery 110, the battery self-heating program can be entered. The required heating power is determined based on the power battery 110 heating demand, that is, based on the temperature requirement parameters of the power battery 110 during self-heating. For example, if the current power battery 110 temperature is relatively low, the required heating power will be higher; if the current power battery 110 temperature is relatively high, the required heating power will be lower. After obtaining the required heating power, the amplitude ipk and frequency f of the self-heating current of the N line can be determined based on the required heating power. After obtaining the amplitude ipk and frequency f of the self-heating current of the N line, the target heating current can be determined based on the amplitude ipk and frequency f. The target heating balancing current In* can also be determined based on the target balancing current indc, the amplitude ipk and frequency f of the target self-heating current, and the current time using the above formula (1).

[0065] It should be noted that the required heating power corresponding to the temperature requirement parameters 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 calibrated on the bench first, and can generally be obtained using a table lookup or linear fitting method.

[0066] According to one embodiment of the present invention, the controller 140 is further configured to: obtain the actual phase current of the motor; obtain the common mode voltage according to the target heating balancing current and the actual phase current; and adjust the first control signal of the motor controller according to the common mode voltage.

[0067] Specifically, after receiving the power battery balancing instruction, the actual phase current of each phase of the motor is obtained, and the N-line current value of the motor is calculated based on the phase current value of each phase of the motor. By integrating the N-line current value, the tolerance ΔQ of the discharge amount of the first battery pack E1 and the second battery pack E2 is calculated. By integrating the tolerance ΔQ, a given target balancing current indc is obtained. After obtaining the target balancing current indc, for example, the target heating balancing current in* is obtained by the above formula (1). Based on the neutral line target heating balancing current in* and the actual N-line current in (the actual N current in is calculated by the sum of the actual N current in and the actual phase currents of each motor being zero), the common mode voltage Un of the bridge arm control is obtained through PI or PR closed-loop control. The first control signal of the motor controller is adjusted based on the common mode voltage Un. By adjusting the duty cycle of each phase bridge arm, the positive and negative busbar currents are adjusted to achieve self-heating and balancing of the first battery pack E1 and the second battery pack E2 when the vehicle is in the charging state.

[0068] According to one embodiment of the present invention, the controller 140 is configured to: in a third preset state, detect that the absolute value of the difference between the capacitance of the first battery group E1 and the capacitance of the second battery group E2 is not less than a preset threshold, control the bridge arm of the motor controller 120, and balance the first battery group E1 and the second battery group E2.

[0069] Specifically, when it is detected that the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 is not less than a preset threshold, it indicates 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 currently large, and the power battery 110 is not in a balanced state. That is, in the third preset state (the state in which the power battery 110 is only performing charge balancing), the bridge arm of the motor controller 120 can be controlled to balance the first battery pack E1 and the second battery pack E2, so 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 reduced. For example, when the capacitance of the first battery pack E1 is large and the capacitance of the second battery pack E2 is small, by controlling the bridge arm of the motor controller 120, the discharge time of the first battery pack E1 can be extended, and the charging time of the second battery pack E2 can be extended, thereby achieving capacitance balancing between the first battery pack E1 and the second battery pack E2.

[0070] In summary, according to an embodiment of the present invention, a battery dynamic balancing device includes a power battery including a first battery group and a second battery group connected in series, and a first node is provided between the first battery group and the second battery group. A first terminal of a motor controller is connected to the positive electrode of the first battery group, a second terminal of the motor controller is connected to the negative electrode of the second battery group, a positive electrode of a DC charge / discharge port is connected to a first bus terminal of the motor controller, a negative electrode of the DC charge / discharge port is connected to a second bus terminal of the motor controller, and a controller is connected to the motor controller. The controller is configured to: in a first preset state, charge the power battery through the DC charge / discharge port, and control the bridge arm of the motor controller to cause the first battery group and the second battery group to charge and discharge alternately, so as to achieve self-heating of the first battery group and the second battery group, and cause the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold. Thus, the balancing device can achieve dynamic balancing of the charge between the first battery group and the second battery group during the self-heating process when the power battery is charging, thereby improving the battery performance and extending the battery life.

[0071] Corresponding to the above embodiment, the present invention further proposes a control method for a battery dynamic balancing device.

[0072] like Figure 3 As shown, the control method of the battery dynamic balancing device according to the embodiment of the present invention includes the following steps:

[0073] S1, in the first preset state, charges the power battery through the DC charging and discharging port, and controls the bridge arm of the motor controller, causing the first battery group and the second battery group to charge and discharge alternately, so as to achieve self-heating of the first battery group and the second battery group, and cause the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than the preset threshold.

[0074] The following combination Figure 4 The control method of the present invention will be described.

[0075] As a specific example, the control method of the battery dynamic balancing device of the present invention may include the following steps:

[0076] S100: The MCU obtains a battery self-heating requirement signal and enters the battery self-heating program.

[0077] S101: Determine whether self-heating is required based on the current battery temperature. If yes, go to step S102; if not, go to step S108.

[0078] S102, controlling the switch module of the battery dynamic balancing device to close.

[0079] S103 , determining the required heating power according to the battery temperature, determining the amplitude and frequency of the self-heating current, and determining the initial bias current according to the initial voltage or capacity of the battery pack.

[0080] S104: Determine whether a battery active balancing command is received. If yes, go to step S105; if not, go to step S110.

[0081] S105: Collect the currents of each motor phase and calculate the motor neutral line current value based on the motor phase current values. Integrate the neutral line current values ​​over N1 self-heating cycles to obtain the discharge capacity difference. Perform PID calculation on the discharge capacity difference to obtain a new neutral line self-heating balancing current. Perform dynamic battery balancing control based on the new neutral line self-heating balancing current. After executing N2 self-heating cycles, the neutral line self-heating balancing current is zero, and the PID integral value of the discharge capacity difference is cleared. The discharge capacity difference PID calculation is not performed during the N2 self-heating cycles. Both N1 and N2 are positive integers, and N2 is much larger than N1 (e.g., N2 = 100N1).

[0082] S106, obtaining the target heating balancing current value and the actual phase current value, performing PI or PR closed-loop control, and calculating the duty cycle of the self-heating bridge arm.

[0083] S107, exit the battery self-heating program.

[0084] S108 , adjusting the battery self-heating target current value to zero according to the battery heating requirement.

[0085] S109 , controlling the switch module of the battery dynamic balancing device to be turned off, and entering step S107 .

[0086] S110 , the self-heating dynamic balancing current is zero, and the PID integral value of the dynamic voltage or discharge capacity difference of the battery pack is cleared, and the process proceeds to step S106 .

[0087] It should be noted that for details not disclosed in the control method of the battery dynamic balancing device according to the embodiment of the present invention, please refer to the details disclosed in the battery dynamic balancing device according to the embodiment of the present invention, and no further details will be given here.

[0088] According to an embodiment of the present invention, a control method for a battery dynamic balancing device includes: a power battery, a motor controller, a DC charge / discharge port, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between the first battery pack and the second battery pack. A first terminal of the motor controller is connected to the positive electrode of the first battery pack, a second terminal of the motor controller is connected to the negative electrode of the second battery pack, a positive electrode of the DC charge / discharge port is connected to a first bus terminal of the motor controller, a negative electrode of the DC charge / discharge port is connected to a second bus terminal of the motor controller, and the controller is connected to the motor controller. The method is applied to the controller and includes: in a first preset state, charging the power battery through the DC charge / discharge port, and controlling a bridge arm of the motor controller to cause the first battery pack and the second battery pack to alternately charge and discharge, thereby achieving self-heating of the first battery pack and the second battery pack, and causing the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold. As a result, the method can achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the self-heating process when the power battery is charging, thereby improving battery performance and extending battery life.

[0089] Corresponding to the above embodiment, the present invention also provides a vehicle.

[0090] like Figure 5 As shown, a vehicle 200 according to an embodiment of the present invention may include the above-mentioned battery dynamic balancing device 100 .

[0091] According to the vehicle of the embodiment of the present invention, by including the above-mentioned battery dynamic balancing device, it is possible to achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the self-heating process when the power battery is charging, thereby improving the battery performance and extending the battery life.

[0092] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0093] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement the logic gate circuit for implementing a logic function on a data signal.

[0094] discrete logic circuits, application-specific integrated circuits with suitable combinational logic gate circuits, programmable gate arrays (PGA), and now field programmable gate arrays (FPGA).

[0095] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention.

[0096] The same descriptions do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0097] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0098] 5 In the present invention, unless otherwise specified and limited, the terms "install", "connect", "connect", "fix"

[0099] Terms such as "connection" and "connectivity" should be broadly understood. For example, "connection" may refer to a fixed connection, a detachable connection, or an integral connection; "connection" may refer to a mechanical connection or an electrical connection; "connection" may refer to a direct connection or an indirect connection through an intermediate medium; "connection" may refer to internal communication between two components or an interaction between two components, unless otherwise specifically defined. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0100] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present invention. A person skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A battery dynamic balancing device, characterized in that: include: A power battery, comprising a first battery group and a second battery group connected in series, with a first node between the first battery group and the second battery group; a motor controller, wherein a first end of the motor controller is connected to the positive electrode of the first battery pack, and a second end of the motor controller is connected to the negative electrode of the second battery pack; A DC charge and discharge port, wherein the positive electrode of the DC charge and discharge port is connected to the first bus terminal of the motor controller, and the negative electrode of the DC charge and discharge port is connected to the second bus terminal of the motor controller; A controller connected to the motor controller, wherein the controller is configured to: in a first preset state, charge the power battery through the DC charge and discharge port, and control the bridge arm of the motor controller to cause the first battery group and the second battery group to be alternately charged and discharged to achieve self-heating of the first battery group and the second battery group, and cause the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold.

2. The battery dynamic balancing device according to claim 1, characterized in that: It also includes a motor, and the motor controller includes at least two-phase first bridge arms, the first end of each phase first bridge arm is connected to the positive pole of the first battery pack, and the second end of each phase first bridge arm is connected to the negative pole of the second battery pack; the motor includes at least two-phase first inductors, the first end of each phase first inductor is connected to the corresponding first bridge arm, and the second end of each phase first inductor is connected to the first node; the motor leads out an N line, and the N line is connected to the first node.

3. The battery dynamic balancing device according to claim 2, characterized in that: It also includes: a DC charge and discharge port, wherein the positive electrode of the DC charge and discharge port is connected to the N line, and the negative electrode of the DC charge and discharge port is connected to the second bus terminal of the motor controller; The controller is configured to: in a second preset state, control the bridge arm of the motor controller to boost and charge the power battery.

4. The battery dynamic balancing device according to claim 3, characterized in that: The controller is configured to: Collecting balanced battery parameters and temperature requirement parameters of the power battery; A target balancing current is obtained according to the balancing battery parameters, and a target self-heating current is obtained according to the temperature requirement parameters, and a first control signal of the motor controller is adjusted and controlled according to the target balancing current, the target self-heating current and the actual phase current of the motor to perform self-heating and balancing processing on the first battery group and the second battery group.

5. The battery dynamic equalization device according to claim 4, characterized in that: The controller is configured to: integrate and calculate the balancing battery parameters to obtain the target balancing current, wherein the balancing battery parameters include: one of a discharge capacity difference, a voltage difference, and an instantaneous power difference, wherein the discharge capacity difference, the voltage difference, and the instantaneous power difference respectively represent a discharge capacity difference, a voltage difference, and an instantaneous power difference between the first battery group and the second battery group.

6. The battery dynamic equalization device according to claim 5, characterized in that: The equalizing battery parameter is the discharge capacity difference; The controller is configured to: collect the phase current of each phase of the motor; calculate the N-line current of the motor according to the phase current of each phase of the motor; and integrate the N-line current to obtain the discharge capacity difference.

7. The battery dynamic balancing device according to claim 5, characterized in that: The equalizing battery parameter is the discharge capacity difference; The controller is configured to: collect the bus positive current and bus negative current of the power battery; perform ampere-hour integration on the bus positive current of the power battery to obtain the discharge capacity of the first battery group, and perform ampere-hour integration on the bus negative current of the power battery to obtain the discharge capacity of the second battery group; and obtain the discharge capacity difference based on the discharge capacity of the first battery group and the discharge capacity of the second battery group.

8. The battery dynamic balancing device according to claim 5, characterized in that: The equalizing battery parameter is the discharge capacity difference; The controller is configured to: collect the bus positive current of the motor controller and the bus negative current of the motor controller; integrate the bus positive current in ampere-hours to obtain the discharge capacity of the first battery group, and integrate the bus negative current in ampere-hours to obtain the discharge capacity of the second battery group; and obtain the discharge capacity difference based on the discharge capacity of the first battery group and the discharge capacity of the second battery group.

9. The battery dynamic equalization device according to claim 5, characterized in that: The balancing current parameter is the voltage difference; The controller is configured to: collect the bus voltage of the motor controller and the voltage of the second battery group; calculate the voltage of the first battery group based on the bus voltage and the voltage of the second battery group; and determine the voltage difference based on the voltage of the first battery group and the voltage of the second battery group.

10. The battery dynamic equalization device according to claim 5, characterized in that: The balancing current parameter is the instantaneous power difference; The controller is configured to: collect the bus positive current, bus negative current, voltage of the first battery group and voltage of the second battery group of the power battery; determine the instantaneous power of the first battery group based on the bus positive current and the voltage of the first battery group, and determine the instantaneous power of the second battery group based on the bus negative current and the voltage of the second battery group; determine the instantaneous power difference based on the instantaneous power of the first battery group and the instantaneous power of the second battery group.

11. The battery dynamic equalization device according to claim 4, characterized in that: The controller is configured to: obtain a required heating power according to the temperature requirement parameter; determine an amplitude and a frequency of a self-heating current of the N line according to the required heating power; and determine a target self-heating current according to the amplitude and the frequency.

12. The battery dynamic equalization device according to claim 11, characterized in that: The controller is further configured to obtain a target heating balancing current by using the following formula: In*=indc+ipk·sin(2·π·f·t) Wherein, In* represents the target heating balancing current, indc represents the target balancing current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents time.

13. The battery dynamic equalization device according to claim 12, characterized in that: The controller is further configured to: Obtaining the actual phase current of the motor; obtaining a common mode voltage according to the target heating balancing current and the actual phase current; A first control signal of the motor controller is adjusted according to the common mode voltage.

14. The battery dynamic equalization device according to claim 1, characterized in that: The controller is configured to: in a third preset state, detect that the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group is not less than the preset threshold, control the bridge arm of the motor controller, and balance the first battery group and the second battery group.

15. A control method for a battery dynamic balancing device, characterized in that: The battery dynamic balancing device includes: a power battery, a motor controller, a DC charge and discharge port, and a controller, wherein the power battery includes a first battery group and a second battery group connected in series, and a first node is provided between the first battery group and the second battery group. The first terminal of the motor controller is connected to the positive electrode of the first battery group, and the second terminal of the motor controller is connected to the negative electrode of the second battery group. The positive electrode of the DC charge and discharge port is connected to the first bus terminal of the motor controller, and the negative electrode of the DC charge and discharge port is connected to the second bus terminal of the motor controller. The controller is connected to the motor controller. The method is applied to the controller and includes: In a first preset state, the power battery is charged through the DC charge and discharge port, and the bridge arm of the motor controller is controlled to cause the first battery group and the second battery group to be alternately charged and discharged to achieve self-heating of the first battery group and the second battery group, and cause the absolute value of the difference between the capacitance of the first battery group and the capacitance of the second battery group to be lower than a preset threshold.

16. A vehicle, characterized in that: The invention comprises the battery dynamic balancing device according to any one of claims 1 to 14.

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