Battery self-heating system and vehicle

Abstract

The present disclosure relates to a battery self-heating system and a vehicle, so as to avoid abnormalities in the electric drive module when driving the vehicle during the battery self-heating process. The system includes: a power battery pack, a first electric drive module, a second electric drive module, a third electric drive module and a controller, wherein the controller is configured to: control the power battery pack to supply power to the first motor controller to drive the first motor, and in a first preset state, control the second electric drive module to store the electric energy released by the first battery pack, and control the third electric drive module to release the stored energy to the second battery pack, and in a second preset state, control the second electric drive module to release the stored energy to the first battery pack, and control the third electric drive module to store the electric energy released by the second battery pack, and the first preset state and the second preset state are executed alternately.

Description

Technical Field

[0001] The present disclosure relates to electric vehicle technology, and in particular, to a battery self-heating system and a vehicle. Background Art

[0002] In response to energy conservation and emission reduction, more and more electric vehicles are entering the public eye. When electric vehicles are in a low temperature environment, the low temperature reduces the activity of the positive and negative electrode materials and the electrolyte in the battery, and its charging and discharging performance will be greatly reduced. In order to ensure the power of electric vehicles in low temperature environments, the batteries of electric vehicles can be heated to increase the temperature of the battery body to ensure the battery charging and discharging performance. In related technologies, battery heating is achieved by alternating charging and discharging between the battery pack and the energy storage element, but in the current charging and discharging process, the terminal voltage of the battery pack fluctuates greatly. If the battery pack is connected to the motor controller and the motor drives the vehicle, this fluctuation may cause delays or abnormalities in the control of the motor controller. Summary of the invention

[0003] The purpose of the present disclosure is to provide a battery self-heating system and a vehicle, aiming to solve the above-mentioned technical problems.

[0004] In order to achieve the above-mentioned object, a first aspect of the present disclosure provides a battery self-heating system, which is applied to a vehicle, and the system comprises:

[0005] A power battery pack, wherein the power battery comprises a first battery group and a second battery group connected in series;

[0006] A first electric drive module, the first electric drive module comprising a first motor and a first motor controller, the first motor controller being used to drive the first motor to drive the vehicle;

[0007] a second electric drive module, the second electric drive module being connected to the first battery pack;

[0008] a third electric drive module, the third electric drive module being connected to the second battery pack;

[0009] A controller is connected to the first motor controller, the second electric drive module and the third electric drive module, and the controller is configured to: control the power battery pack to supply power to the first motor controller to drive the first motor, and in a first preset state, control the second electric drive module to store the electric energy released by the first battery pack, and control the third electric drive module to release the stored energy to the second battery pack; in a second preset state, control the second electric drive module to release the stored energy to the first battery pack, and control the third electric drive module to store the electric energy released by the second battery pack, and the first preset state and the second preset state are executed alternately.

[0010] Optionally, the second electric drive module includes a second motor controller and a second motor, the second motor controller is connected to the first battery pack, and the second motor is connected to the second motor controller;

[0011] The third electric drive module includes a third motor controller and a third motor. The third motor controller is connected to the second battery pack, and the third motor is connected to the third motor controller.

[0012] Optionally, the second motor controller includes a multi-phase first bridge arm, the first ends of the multi-phase first bridge arm are connected in common to form a first bus terminal, the second ends of the multi-phase first bridge arm are connected in common to form a second bus terminal, the first bus terminal is connected to the positive electrode of the first battery pack, and the second bus terminal is connected to the negative electrode of the first battery pack, the second motor includes a multi-phase first winding, the first end of each phase of the first winding is connected to the midpoint of the corresponding bridge arm in the multi-phase first bridge arm, and the second ends of the multi-phase first winding are connected in common and lead out a first N line;

[0013] The second electric drive module further includes a first capacitor, a first end of the first capacitor is connected to the first N line, and a second end of the first capacitor is connected to the second bus terminal;

[0014] The third motor controller includes a multi-phase second bridge arm, the first ends of the multi-phase second bridge arms are connected together to form a third bus terminal, the second ends of the multi-phase second bridge arms are connected together to form a fourth bus terminal, the third bus terminal is connected to the positive electrode of the second battery pack, and the fourth bus terminal is connected to the negative electrode of the second battery pack, the third motor includes a multi-phase second winding, the first end of each phase of the second winding is connected to the midpoint of the corresponding bridge arm in the multi-phase second bridge arm, and the second ends of the multi-phase second winding are connected together and lead out a second N line;

[0015] The third electric drive module further includes a second capacitor, a first end of the second capacitor is connected to the second N line, and a second end of the second capacitor is connected to the fourth bus terminal.

[0016] Optionally, the controller is configured to:

[0017] In a first time period of the first preset state, the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned off, the first battery pack is controlled to discharge to charge the first capacitor, and the second capacitor is controlled to discharge to store energy in the multi-phase second winding;

[0018] During the second time period of the first preset state, the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be closed, the multi-phase first winding is controlled to discharge to charge the first capacitor, and the second capacitor and the multi-phase second winding are controlled to discharge to charge the second battery pack.

[0019] Optionally, the controller is configured to:

[0020] In a first time period of the second preset state, the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned off, the second battery pack is controlled to discharge to charge the second capacitor, and the first capacitor is controlled to discharge to store energy in the multi-phase first winding;

[0021] During the second time period of the second preset state, the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be closed, the multi-phase second winding is controlled to discharge to charge the second capacitor, and the first capacitor and the multi-phase first winding are controlled to discharge to charge the first battery pack.

[0022] Optionally, the controller is further configured to:

[0023] In the first preset state, a first voltage variation amount for controlling the first battery pack to discharge is the same as a second voltage variation amount for controlling the second battery pack to charge;

[0024] In the second preset state, the third voltage variation amount for controlling the discharge of the second battery pack is the same as the fourth voltage variation amount for charging the first battery pack.

[0025] Optionally, the controller is further configured to:

[0026] In the first preset state, controlling the ratio between the current value flowing through the first battery group and the current value flowing through the second battery group to be equal to the ratio between the resistance value of the second battery group and the resistance value of the first battery group;

[0027] In the second preset state, a ratio between a current value flowing through the first battery group and a current value flowing through the second battery group is controlled to be equal to a ratio between a resistance value of the second battery group and a resistance value of the first battery group.

[0028] Optionally, the system further comprises a switch module, wherein the switch module is connected to the controller, and the controller is further configured to:

[0029] The switch module is controlled to be turned on or off, and the second electric drive module and / or the third electric drive module are controlled to enter a driving mode, or the second electric drive module and the third electric drive module are controlled to enter a self-heating mode.

[0030] Optionally, the switch module includes: a first conversion switch, a second conversion switch, a third conversion switch and a fourth conversion switch, wherein the third conversion switch and the fourth conversion switch are both double-position switches;

[0031] The first conversion switch is arranged on a connection line between the first N line and the first capacitor;

[0032] The second conversion switch is arranged on a connection line between the second N line and the second capacitor;

[0033] The static contact of the third conversion switch is respectively connected to the first capacitor and the first bus terminal, the first moving contact of the third conversion switch is respectively connected to the negative terminal of the first battery pack and the positive terminal of the second battery pack, and the second moving contact of the third conversion switch is connected to the negative terminal of the second battery pack;

[0034] The static contact of the fourth conversion switch is connected to the third bus terminal, the first moving contact of the fourth conversion switch is connected to the positive terminal of the first battery pack, and the second moving contact of the fourth conversion switch is connected to the negative terminal of the first battery pack and the positive terminal of the second battery pack respectively;

[0035] The controller is configured to: control the first conversion switch and the second conversion switch to close, control the static contact of the third conversion switch and the first moving contact of the third conversion switch to be connected, and control the static contact of the fourth conversion switch and the second moving contact of the fourth conversion switch to be connected, and control the second electric drive module and the third electric drive module to enter the self-heating mode.

[0036] Optionally, the controller is further configured to:

[0037] Control the first conversion switch and the second conversion switch to be disconnected, control the static contact of the third conversion switch and the second moving contact of the third conversion switch to be connected, and control the static contact of the fourth conversion switch and the first moving contact of the fourth conversion switch to be connected, control the second electric drive module to enter the driving mode, and control the third electric drive module to enter the driving mode.

[0038] Optionally, the system further comprises a fourth electric drive module;

[0039] The fourth electric drive module includes a fourth motor controller, a fourth motor and a third capacitor. The second battery pack is connected to the fourth motor controller, the first end of the fourth motor is connected to the fourth motor controller, and the second end of the fourth motor is connected in series with the third capacitor and then connected to the negative electrode of the second battery pack.

[0040] Optionally, the system further comprises a fifth electric drive module;

[0041] The fifth electric drive module includes a fifth motor controller and a fifth motor. The second battery pack is connected to the fifth motor controller. The first end of the fifth motor is connected to the fifth motor controller. The second end of the fifth motor is connected to the second motor.

[0042] A second aspect of the present disclosure further provides a vehicle, comprising the battery self-heating system as described in any one of the first aspects above.

[0043] The battery self-heating system provided by the present disclosure is applied to a vehicle, and the system includes a power battery pack, a first electric drive module, a second electric drive module, a third electric drive module, and a controller, which controls the power battery pack to supply power to the first motor controller to drive the first motor, and controls the second electric drive module to store the electric energy released by the first battery pack in a first preset state, and controls the third electric drive module to release the stored energy to the second battery pack, and controls the second electric drive module to release the stored energy to the first battery pack in a second preset state, and controls the third electric drive module to store the electric energy released by the second battery pack, and the first preset state and the second preset state are executed alternately. In this way, the voltage fluctuations of the first battery pack and the second battery pack during the self-heating process offset each other, so that the terminal voltage fluctuation of the power battery pack is small, thereby avoiding abnormality of the first electric drive module when driving the vehicle.

[0044] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0046] Figure 1 It is a schematic diagram of a battery self-heating circuit of the related art;

[0047] Figure 2 is a schematic diagram of a battery self-heating system provided by an embodiment of the present disclosure;

[0048] Figure 3 is a schematic diagram of another battery self-heating system provided by an embodiment of the present disclosure;

[0049] Figure 4 is a circuit diagram of a battery self-heating system provided by an embodiment of the present disclosure;

[0050] Figure 5 is a schematic diagram of the current direction of a battery self-heating system when it is working, provided by an embodiment of the present disclosure;

[0051] Figure 6 is a schematic diagram of the current direction of another battery self-heating system provided by an embodiment of the present disclosure when it is working;

[0052] Figure 7 is a schematic diagram of the current direction of another battery self-heating system provided by an embodiment of the present disclosure when it is working;

[0053] Figure 8 is a schematic diagram of the current direction of another battery self-heating system provided by an embodiment of the present disclosure when it is working;

[0054] Fig. 9 is a circuit diagram of another battery self-heating system provided by an embodiment of the present disclosure;

[0055] Fig.10 is a circuit diagram of another battery self-heating system provided in an embodiment of the present disclosure.

[0056] Description of Reference Numerals

[0057] 11-battery; 12-bus capacitor; 13-energy storage capacitor; 14-inverter; 15-motor winding; E1-first battery pack; E2-second battery pack; K1-first conversion switch; K2-second conversion switch; K3-third conversion switch; K4-fourth conversion switch; C1-first capacitor; C2-second capacitor; C3-third capacitor; 1-first motor; 2-first motor controller; 3-multi-phase first winding; 4-multi-phase first bridge arm; 5-multi-phase second winding; 6-multi-phase second bridge arm. DETAILED DESCRIPTION

[0058] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0059] It should be understood that the various steps described in the method implementation of the present disclosure may be performed in different orders and / or in parallel. In addition, the method implementation may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect. The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the description below.

[0060] It should be noted that the concepts of "first", "second", etc. mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units. It should be noted that the modifications of "one" and "multiple" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, they should be understood as "one or more".

[0061] In response to energy conservation and emission reduction, more and more electric vehicles are being chosen by more users. In order to improve the driving performance of electric vehicles, multi-motor electric vehicles known for their strong power are gradually entering the public's field of vision. Strong power requires good battery charging and discharging performance, but when electric vehicles are in a low temperature environment, especially below -10°C, the low temperature reduces the activity of the positive and negative electrode materials and the electrolyte in the battery, and its charging and discharging performance will be greatly reduced. In order to ensure the power of electric vehicles in low temperature environments, the battery of the electric vehicle can be heated to increase the temperature of the battery body to ensure the battery charging and discharging performance.

[0062] At present, batteries can be heated by external heating and internal heating. Among them, external heating heats the battery by adding additional heating equipment. This heating method adds additional heating equipment, which leads to high costs. In addition, the external heat dissipation is fast and there is a certain distance between the external temperature and the internal battery, resulting in low heating efficiency. The principle of the other internal heating method is mainly to use the battery cycle charge and discharge, relying on the battery's own internal resistance to generate heat. For example, Figure 1 As shown, the battery self-heating circuit includes a battery 11, a bus capacitor 12, an energy storage capacitor 13, an inverter 14 and a motor winding 15, wherein the battery 11, the bus capacitor 12 and the inverter 14 are connected in parallel, and the battery 11 is oscillatedly heated by the inverter 14, the motor winding 15 and the energy storage capacitor 13, and during the oscillation heating process, the battery 11 is in an alternating charge and discharge state, so the battery voltage fluctuates greatly, and the fluctuation may cause damage to the battery and reduce the battery life.

[0063] In addition, if the vehicle is driven by the motor and motor controller when the battery is self-heating, it is limited by the heating principle of battery self-heating, that is, when a large current flows through the battery, the internal resistance of the battery heats up, thereby heating the battery. In other words, in order to generate a larger amount of heating, a larger self-heating current is required when the battery internal resistance and heating time remain unchanged. The battery voltage fluctuation ∆U=I*Rcell, when the total internal resistance Rcell of the battery remains unchanged, the larger the battery current I, the larger the battery voltage fluctuation ∆U, which may cause delays or abnormalities in the control of the motor controller, and at the same time, abnormalities in the torque control of the motor may also occur.

[0064] In view of this, the present disclosure provides a battery self-heating system and a vehicle to solve the above problems.

[0065] The technical solution of the present disclosure is described in detail below with reference to embodiments.

[0066] The present disclosure provides a battery self-heating system for a vehicle. Figure 2 The battery self-heating system includes: a power battery pack 21, a first electric drive module 22, a second electric drive module 23, a third electric drive module 24 and a controller 25.

[0067] The power battery pack 21 includes a first battery pack E1 and a second battery pack E2 connected in series, the first electric drive module 22 includes a first motor 221 and a first motor controller 222, the first motor controller is used to drive the first motor to drive the vehicle, the second electric drive module 23 is connected to the first battery pack E1, and the third electric drive module 24 is connected to the second battery pack E2. The controller 25 is connected to the first motor controller 222, the second electric drive module 23 and the third electric drive module 24, and the controller 25 is configured to: control the power battery pack 21 to supply power to the first motor controller 222 to drive the first motor 221, and in a first preset state, control the second electric drive module 23 to store the electric energy released by the first battery pack E1, and control the third electric drive module 24 to release the stored energy to the second battery pack E2, and in a second preset state, control the second electric drive module 23 to release the stored energy to the first battery pack E1, and control the third electric drive module 24 to store the electric energy released by the second battery pack E2, and the first preset state and the second preset state are executed alternately.

[0068] When the above-mentioned battery self-heating system is used for battery self-heating, the voltage fluctuations of the first battery pack and the second battery pack offset each other, so that the terminal voltage fluctuation of the power battery pack is smaller, thereby avoiding abnormalities of the first electric drive module when driving the vehicle.

[0069] In order to enable those skilled in the art to better understand the battery self-heating system provided by the present disclosure, the above steps are described in detail with examples below.

[0070] It is worth noting that for vehicles with multiple motors, multiple motor controllers and multiple motors on the vehicle can be used to self-heat the power battery pack. Figure 3 , taking a vehicle with multiple three-phase motors as an example, the power battery pack is divided into two battery groups (E1 and E2), and one group of motor controllers and motors is used as the second electric drive module, and the other group of motor controllers and motors is used as the third electric drive module. Therefore, in a possible manner, the second electric drive module includes a second motor controller and a second motor, the second motor controller is connected to the first battery group, and the second motor is connected to the second motor controller, and the third electric drive module includes a third motor controller and a third motor, the third motor controller is connected to the second battery group, and the third motor is connected to the third motor controller.

[0071] In possible ways, refer to Figure 4 The second motor controller includes a multi-phase first bridge arm 4, the first ends of the multi-phase first bridge arm 4 are connected together to form a first bus terminal, the second ends of the multi-phase first bridge arm 4 are connected together to form a second bus terminal, the first bus terminal is connected to the positive electrode of the first battery pack E1, and the second bus terminal is connected to the negative electrode of the first battery pack E1. The second motor includes a multi-phase first winding 3, the first end of each phase of the first winding is connected to the midpoint of the corresponding bridge arm in the multi-phase first bridge arm 4, and the second end of the multi-phase first winding 3 is connected together and leads to a first N line. The second electric drive module also includes a first capacitor C1, the first end of the first capacitor C1 is connected to the first N line, and the second end of the first capacitor C1 is connected to the second bus terminal. The third motor controller includes a multi-phase second bridge arm 6, the first ends of the multi-phase second bridge arm 6 are connected together to form a third bus terminal, the second ends of the multi-phase second bridge arm 6 are connected together to form a fourth bus terminal, the third bus terminal is connected to the positive electrode of the second battery pack E2, and the fourth bus terminal is connected to the negative electrode of the second battery pack E2. The third motor includes a multi-phase second winding 5, the first end of each phase of the second winding is connected to the midpoint of the corresponding bridge arm in the multi-phase second bridge arm 6, and the second end of the multi-phase second winding 5 is connected together and leads to a second N line. The third electric drive module also includes a second capacitor C2, the first end of the second capacitor C2 is connected to the second N line, and the second end of the second capacitor C2 is connected to the fourth bus terminal.

[0072] In a possible manner, the controller is configured to: in a first time period of a first preset state, control the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm to be turned on, and control the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm to be turned off, control the first battery pack to discharge, so as to charge the first capacitor, and control the second capacitor to discharge, so as to store energy in the multi-phase second winding. In a second time period of the first preset state, control the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm to be turned on, and control the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm to be turned off, control the multi-phase first winding to discharge, so as to charge the first capacitor, and control the second capacitor and the multi-phase second winding to discharge, so as to charge the second battery pack.

[0073] Further, the controller is configured to: in a first time period of a second preset state, control the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm to be turned on, and control the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm to be turned off, control the second battery pack to discharge, so as to charge the second capacitor, and control the first capacitor to discharge, so as to store energy in the multi-phase first winding. In a second time period of the second preset state, control the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm to be turned on, and control the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm to be turned off, control the multi-phase second winding to discharge, so as to charge the second capacitor, and control the first capacitor and the multi-phase first winding to discharge, so as to charge the first battery pack.

[0074] For example, in the first time period of the first preset state, referring to Figure 5 The upper bridge arm of the multi-phase first bridge arm 4 and the lower bridge arm of the multi-phase second bridge arm 6 are turned on, and the lower bridge arm of the multi-phase first bridge arm 4 and the upper bridge arm of the multi-phase second bridge arm 6 are turned off, the first battery group E1 discharges, the first capacitor C1 charges, the second capacitor C2 discharges, and the electric energy is stored in the multi-phase second winding 5. During this process, the voltage of the first battery group E1 drops.

[0075] For example, in the second time period of the first preset state, referring to Figure 6 , the lower bridge arm of the multi-phase first bridge arm 4 and the upper bridge arm of the multi-phase second bridge arm 6 are turned on, and the upper bridge arm of the multi-phase first bridge arm 4 and the lower bridge arm of the multi-phase second bridge arm 6 are turned off, the multi-phase first winding 3 is discharged, the first capacitor C1 is charged, the second capacitor C2 and the multi-phase second winding 5 are discharged, and the second battery group E2 is charged. In this process, the voltage of the second battery group E2 rises. According to the unidirectional conduction characteristic of the diode, when the bridge arm is turned off, the current can pass through the parasitic diode of the bridge arm. Therefore, in the second time period of the first preset state, the lower bridge arm of the multi-phase first bridge arm 4 and the upper bridge arm of the multi-phase second bridge arm 6 can be turned on or off.

[0076] It should be noted that, in the first preset state, the voltage drop amplitude ∆U of the first battery group E1 is1 =I 1 *Rcell 1 , the voltage rise of the second battery group E2 is ∆U 2 =I 2 *Rcell 2 , by controlling the current I of the first battery pack 1 and resistor Rcell 1 and the current I of the second battery pack 2 and resistor Rcell 2 , the total voltage fluctuation of the power battery pack can be within a preset voltage fluctuation range, for example, -0.5V to 0.5V. The specific preset voltage fluctuation range can be determined according to the requirements, and the present disclosure does not limit this. 1 =Rcell 2 As long as I 1 =I 2 , the total fluctuation of the voltage of the power battery pack can be 0.

[0077] For example, in the first time period of the second preset state, referring to Figure 7 , the lower bridge arm of the multi-phase first bridge arm 4 and the upper bridge arm of the multi-phase second bridge arm 6 are turned on, and the upper bridge arm of the multi-phase first bridge arm 4 and the lower bridge arm of the multi-phase second bridge arm 6 are turned off, the second battery group E2 discharges, the second capacitor C2 charges, the first capacitor discharges C1, and the electric energy is stored in the multi-phase first winding 3. In this process, the voltage of the second battery group E2 drops.

[0078] For example, in the second time period of the second preset state, referring to Figure 8 , the upper bridge arm of the multi-phase first bridge arm 4 and the lower bridge arm of the multi-phase second bridge arm 6 are turned on, and the lower bridge arm of the multi-phase first bridge arm 4 and the upper bridge arm of the multi-phase second bridge arm 6 are turned off, the multi-phase second winding 5 is discharged, the second capacitor C2 is charged, the first capacitor C1 and the multi-phase first winding 3 are discharged, and the first battery group E1 is charged. In this process, the voltage of the first battery group E1 rises. According to the unidirectional conduction characteristic of the diode, when the bridge arm is turned off, the current can pass through the parasitic diode of the bridge arm. Therefore, in the second time period of the second preset state, the upper bridge arm of the multi-phase first bridge arm 4 and the lower bridge arm of the multi-phase second bridge arm 6 can be turned on or off.

[0079] It should be noted that, in the second preset state, the voltage increase amplitude ∆U of the first battery pack E1 is 1 =I 1 *Rcell 1 , the voltage drop of the second battery group E2 is ∆U 2 =I 2 *Rcell 2 , by controlling the current I of the first battery pack1 and resistor Rcell 1 and the current I of the second battery pack 2 and resistor Rcell 2 , the total voltage fluctuation of the power battery pack can be made within a preset voltage fluctuation range.

[0080] Furthermore, by cycling back and forth between the first preset state and the second preset state, the energy is cyclically charged and discharged between the power battery pack and the capacitor, and the battery self-heating is achieved. In addition, the first motor controller 2 in the first electric drive module can drive the first motor 1 to work normally, achieving self-heating while driving the vehicle.

[0081] In a possible manner, the controller is also configured to: in a first preset state, the first voltage change controlling the discharge of the first battery group is the same as the second voltage change controlling the charging of the second battery group; and in a second preset state, the third voltage change controlling the discharge of the second battery group is the same as the fourth voltage change controlling the charging of the first battery group.

[0082] Further, in a possible manner, the controller is further configured to: in a first preset state, control the ratio between the current value flowing through the first battery pack and the current value flowing through the second battery pack to be equal to the ratio between the resistance value of the second battery pack and the resistance value of the first battery pack. In a second preset state, control the ratio between the current value flowing through the first battery pack and the current value flowing through the second battery pack to be equal to the ratio between the resistance value of the second battery pack and the resistance value of the first battery pack.

[0083] For example, through the charging and discharging process between the first battery pack and the second battery pack during the above-mentioned battery self-heating process, it can be known that the voltage fluctuation is related to the current and resistance of the battery. Since the resistance value of the battery pack has been determined when the battery pack is divided, the total voltage fluctuation of the power battery pack can be adjusted to be within the preset voltage fluctuation range by adjusting the current of the battery pack. For example, the power battery pack is divided into two battery packs with equal number of cells, namely Rcell 1 =Rcell 2 , you can control I 1 =I 2 For another example, if the power battery pack is divided into two battery packs with unequal numbers of cells, and if the total fluctuation of the power battery pack voltage per unit time needs to be controlled to 0, then I 1 / I 2 =Rcell 2 / Rcell 1That is to say, when the ratio between the current value of the first battery pack and the current value flowing through the second battery pack is equal to the ratio between the resistance value of the second battery pack and the resistance value of the first battery pack, the total fluctuation of the voltage of the power battery pack per unit time is equal to 0. Accordingly, if it is only necessary to control the total fluctuation of the voltage of the power battery pack per unit time within a preset voltage fluctuation range, the current of the battery packs divided by the power battery pack can be controlled according to the control relationship that the larger the resistance of the battery pack, the smaller the current. The specific control can be determined according to demand and experiments, and the present disclosure does not limit this.

[0084] In addition, the power battery pack can also be divided into three battery groups, four battery groups, etc., and each battery group is assigned an electric drive module. The present disclosure does not limit the number of battery groups and the number of cells in the battery group, as long as the total voltage fluctuation of the power battery pack is within the preset voltage fluctuation range. For example, taking the resistance value of each cell in the power battery pack as an example, assuming that the number of cells contained in each battery pack is N1, N2, N3...Nn respectively, the self-heating current of each battery pack should satisfy I 1 / I 2 / I 3 / …… / I n =Nn / …… / N3 / N2 / N1. Of course, each battery pack can also be connected in parallel with multiple electric drive modules, as long as the sum of the currents of each electric drive module is controlled to be equal to the current of the battery pack, the currents of the electric drive modules connected in parallel in the same battery pack can be equal or unequal, and the present disclosure does not limit this.

[0085] In a possible manner, a switch may be added to the circuit to control the on and off of the circuit. The system further includes a switch module, the switch module is connected to the controller, and the controller is further configured to: control the on or off of the switch module, and control the second electric drive module and / or the third electric drive module to enter the driving mode, or control the second electric drive module and the third electric drive module to enter the self-heating mode.

[0086] In possible ways, refer to Figure 4 The switch module includes: a first conversion switch K1, a second conversion switch K2, a third conversion switch K3 and a fourth conversion switch K4, wherein the third conversion switch K3 and the fourth conversion switch K4 are both double-position switches.

[0087] The first conversion switch K1 is arranged on the connection line between the first N line and the first capacitor C1, and the second conversion switch K2 is arranged on the connection line between the second N line and the second capacitor C2. The static contact a of the third conversion switch K3 is respectively connected to the first capacitor C1 and the first bus terminal, the first moving contact b of the third conversion switch K3 is respectively connected to the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2, and the second moving contact c of the third conversion switch K3 is connected to the negative terminal of the second battery pack E2. The static contact a of the fourth conversion switch K4 is connected to the third bus terminal, the first moving contact a of the fourth conversion switch K4 is connected to the positive terminal of the first battery pack E1, and the second moving contact c of the fourth conversion switch K4 is respectively connected to the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2. The controller is configured to: control the first conversion switch K1 and the second conversion switch K2 to close, control the static contact a of the third conversion switch K3 to connect with the first moving contact b of the third conversion switch K3, and control the static contact a of the fourth conversion switch K4 to connect with the second moving contact c of the fourth conversion switch K4, and control the second electric drive module and the third electric drive module to enter the self-heating mode. In the self-heating mode, the bridge arm state and current direction of the second electric drive module and the third electric drive module can refer to Figure 5-8 , this disclosure will not be repeated here.

[0088] In a possible manner, the controller is also configured to: control the first conversion switch K1 and the second conversion switch K2 to be disconnected, control the static contact a of the third conversion switch K3 and the second moving contact c of the third conversion switch K3 to be connected, and control the static contact a of the fourth conversion switch K4 and the first moving contact b of the fourth conversion switch K4 to be connected, control the second electric drive module to enter the drive mode, and control the third electric drive module to enter the drive mode.

[0089] For example, the first conversion switch K1 and the second conversion switch K2 are disconnected, the static contact a of the third conversion switch K3 is connected to the second moving contact c of the third conversion switch K3, and the static contact a of the fourth conversion switch K4 is connected to the first moving contact b of the fourth conversion switch K4. At this time, the second electric drive module consisting of the first electric drive module, the second motor and the second motor controller, and the third electric drive module consisting of the third motor and the third motor controller are all connected in parallel with the power battery pack to drive the vehicle. The working process of the motor and the motor controller in the driving mode can refer to the relevant technology, and the present disclosure will not repeat it here.

[0090] In a possible embodiment, the system further comprises a fourth electric drive module, referring to Fig. 9 The fourth electric drive module includes a fourth motor controller, a fourth motor and a third capacitor C3. The second battery pack is connected to the fourth motor controller, the first end of the fourth motor is connected to the fourth motor controller, and the second end of the fourth motor is connected in series with the third capacitor C3 and then connected to the negative electrode of the second battery pack.

[0091] For example, the fourth electric drive module and the third electric drive module are both connected in parallel with the second battery group and controlled in the same preset state. The state of the bridge arm in the fourth electric drive module is consistent with the state of the bridge arm in the third electric drive module. Then the fourth electric drive module and the third electric drive module jointly perform alternating charge and discharge with the second battery group, and when the second battery group is in a charging state, the first battery group is in a discharging state, or when the second battery group is in a discharging state, the first battery group is in a charging state.

[0092] In a possible embodiment, the system further comprises a fifth electric drive module, referring to Fig.10 The fifth electric drive module includes a fifth motor controller and a fifth motor, the second battery pack is connected to the fifth motor controller, the first end of the fifth motor is connected to the fifth motor controller, and the second end of the fifth motor is connected to the second motor.

[0093] For example, the fifth electric drive module and the third electric drive module are both connected in parallel with the second battery group and share the second capacitor C2, so that under the same preset control, the state of the bridge arm in the fifth electric drive module is consistent with the state of the bridge arm in the third electric drive module. The fifth electric drive module and the third electric drive module jointly perform alternating charge and discharge with the second battery group, and when the second battery group is in a charging state, the first battery group is in a discharging state, or when the second battery group is in a discharging state, the first battery group is in a charging state.

[0094] It is worth noting that by using some motor controllers and motors in a multi-motor vehicle as electric drive modules to self-heat the power battery pack, that is, the motor controller and the motor can be used to drive the vehicle, and can also be used to self-heat the power battery pack, without the need to add other components or heating devices, which meets the demand for heating the power battery pack while saving costs. However, for other single-motor vehicles or dual-motor vehicles, the self-heating function of the power battery pack can be achieved by adding bridge arms and windings as electric drive modules. Of course, for multi-motor vehicles, bridge arms and windings can also be added as electric drive modules, and the present disclosure does not limit this.

[0095] For example, the first bridge arm and the second bridge arm may be composed of a single-phase bridge arm or a multi-phase bridge arm. The winding may be a single-phase winding or a multi-phase winding, or a coil in a single-phase motor or a multi-phase motor, which is not limited in the present disclosure. In addition, for an electric drive module that does not participate in driving the vehicle, a six-phase bridge arm and a six-phase motor may be used to replace the six-phase motor. Figure 4 Two three-phase bridge arms and two three-phase motors are shown.

[0096] It should be noted that the controller can be a control unit in a motor controller or an electronic device installed in a vehicle, and the present disclosure does not limit this. A temperature sensor can also be set near the power battery pack to transmit the collected battery temperature to the controller in real time. When the battery temperature is lower than a preset threshold, the controller automatically controls the power battery pack to self-heat. A heating button can also be set on the vehicle, for example, to remind the driver on the vehicle display that the power battery pack is in a low temperature state. The driver can send a signal to the controller to start self-heating through the heating button set on the vehicle display. After receiving the signal, the controller controls the power battery pack to self-heat, etc., and the present disclosure does not limit this.

[0097] In addition, in the process of controlling the battery pack to alternately charge and discharge, one or more of the multiple bridge arms or switches can be controlled to be turned on, thereby controlling the number of windings participating in self-heating, for example Figure 5 In the embodiment, one of the three upper bridge arms of the multi-phase first bridge arm 4 can be selected to be turned on, and the first battery pack E1 discharges to a winding connected to it in the multi-phase first winding 3 and the first capacitor C1. Generally speaking, the more windings participate in self-heating, the higher the efficiency of self-heating. In other possible implementations, the number of windings participating in self-heating can be controlled according to the battery temperature, for example, the lower the battery temperature, the more windings, etc., which is not limited in the present disclosure.

[0098] Based on the same inventive concept, the disclosed embodiment also provides a vehicle, including the above-mentioned battery self-heating system, through which the battery in the vehicle is heated to ensure the performance of the battery in a low temperature environment. In addition, the power battery pack can also be self-heated during the driving of the vehicle.

[0099] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0100] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0101] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A battery self-heating system, characterized in that: Applied to a vehicle, the system comprises: A power battery pack, wherein the power battery comprises a first battery group and a second battery group connected in series; A first electric drive module, the first electric drive module comprising a first motor and a first motor controller, the first motor controller being used to drive the first motor to drive the vehicle; a second electric drive module, the second electric drive module being connected to the first battery pack; a third electric drive module, the third electric drive module being connected to the second battery pack; A controller is connected to the first motor controller, the second electric drive module and the third electric drive module, and the controller is configured to: control the power battery pack to supply power to the first motor controller to drive the first motor, and in a first preset state, control the second electric drive module to store the electric energy released by the first battery pack, and control the third electric drive module to release the stored energy to the second battery pack; in a second preset state, control the second electric drive module to release the stored energy to the first battery pack, and control the third electric drive module to store the electric energy released by the second battery pack, and the first preset state and the second preset state are executed alternately.

2. The system according to claim 1, characterized in that The second electric drive module includes a second motor controller and a second motor, the second motor controller is connected to the first battery pack, and the second motor is connected to the second motor controller; The third electric drive module includes a third motor controller and a third motor. The third motor controller is connected to the second battery pack, and the third motor is connected to the third motor controller.

3. The system according to claim 2, characterized in that The second motor controller includes a multi-phase first bridge arm, the first ends of the multi-phase first bridge arm are connected together to form a first bus terminal, the second ends of the multi-phase first bridge arm are connected together to form a second bus terminal, the first bus terminal is connected to the positive electrode of the first battery pack, and the second bus terminal is connected to the negative electrode of the first battery pack, the second motor includes a multi-phase first winding, the first end of each phase of the first winding is connected to the midpoint of the corresponding bridge arm in the multi-phase first bridge arm, and the second ends of the multi-phase first winding are connected together and lead out a first N line; The second electric drive module further includes a first capacitor, a first end of the first capacitor is connected to the first N line, and a second end of the first capacitor is connected to the second bus terminal; The third motor controller includes a multi-phase second bridge arm, the first ends of the multi-phase second bridge arms are connected together to form a third bus terminal, the second ends of the multi-phase second bridge arms are connected together to form a fourth bus terminal, the third bus terminal is connected to the positive electrode of the second battery pack, and the fourth bus terminal is connected to the negative electrode of the second battery pack, the third motor includes a multi-phase second winding, the first end of each phase of the second winding is connected to the midpoint of the corresponding bridge arm in the multi-phase second bridge arm, and the second ends of the multi-phase second winding are connected together and lead out a second N line; The third electric drive module further includes a second capacitor, a first end of the second capacitor is connected to the second N line, and a second end of the second capacitor is connected to the fourth bus terminal.

4. The system according to claim 3, characterized in that The controller is configured to: In a first time period of the first preset state, the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned off, the first battery pack is controlled to discharge to charge the first capacitor, and the second capacitor is controlled to discharge to store energy in the multi-phase second winding; During the second time period of the first preset state, the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be closed, the multi-phase first winding is controlled to discharge to charge the first capacitor, and the second capacitor and the multi-phase second winding are controlled to discharge to charge the second battery pack.

5. The system according to claim 4, characterized in that The controller is configured to: In a first time period of the second preset state, the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned off, the second battery pack is controlled to discharge to charge the second capacitor, and the first capacitor is controlled to discharge to store energy in the multi-phase first winding; During the second time period of the second preset state, the upper bridge arm of the multi-phase first bridge arm and the lower bridge arm of the multi-phase second bridge arm are controlled to be turned on, and the lower bridge arm of the multi-phase first bridge arm and the upper bridge arm of the multi-phase second bridge arm are controlled to be closed, the multi-phase second winding is controlled to discharge to charge the second capacitor, and the first capacitor and the multi-phase first winding are controlled to discharge to charge the first battery pack.

6. The system according to claim 5, characterized in that The controller is also configured to: In the first preset state, a first voltage variation amount for controlling the first battery pack to discharge is the same as a second voltage variation amount for controlling the second battery pack to charge; In the second preset state, the third voltage variation amount for controlling the discharge of the second battery pack is the same as the fourth voltage variation amount for charging the first battery pack.

7. The system according to claim 6, characterized in that The controller is also configured to: In the first preset state, controlling the ratio between the current value flowing through the first battery group and the current value flowing through the second battery group to be equal to the ratio between the resistance value of the second battery group and the resistance value of the first battery group; In the second preset state, a ratio between a current value flowing through the first battery group and a current value flowing through the second battery group is controlled to be equal to a ratio between a resistance value of the second battery group and a resistance value of the first battery group.

8. The system according to claim 3, characterized in that The system further comprises a switch module, wherein the switch module is connected to the controller, and the controller is further configured to: The switch module is controlled to be turned on or off, and the second electric drive module and / or the third electric drive module are controlled to enter a driving mode, or the second electric drive module and the third electric drive module are controlled to enter a self-heating mode.

9. The system according to claim 8, characterized in that The switch module comprises: a first conversion switch, a second conversion switch, a third conversion switch and a fourth conversion switch, wherein the third conversion switch and the fourth conversion switch are both double-position switches; The first conversion switch is arranged on a connection line between the first N line and the first capacitor; The second conversion switch is arranged on a connection line between the second N line and the second capacitor; The static contact of the third conversion switch is respectively connected to the first capacitor and the first bus terminal, the first moving contact of the third conversion switch is respectively connected to the negative terminal of the first battery pack and the positive terminal of the second battery pack, and the second moving contact of the third conversion switch is connected to the negative terminal of the second battery pack; The static contact of the fourth conversion switch is connected to the third bus terminal, the first moving contact of the fourth conversion switch is connected to the positive terminal of the first battery pack, and the second moving contact of the fourth conversion switch is connected to the negative terminal of the first battery pack and the positive terminal of the second battery pack respectively; The controller is configured to: control the first conversion switch and the second conversion switch to close, control the static contact of the third conversion switch and the first moving contact of the third conversion switch to be connected, and control the static contact of the fourth conversion switch and the second moving contact of the fourth conversion switch to be connected, and control the second electric drive module and the third electric drive module to enter the self-heating mode.

10. The system according to claim 9, characterized in that The controller is also configured to: Control the first conversion switch and the second conversion switch to be disconnected, control the static contact of the third conversion switch and the second moving contact of the third conversion switch to be connected, and control the static contact of the fourth conversion switch and the first moving contact of the fourth conversion switch to be connected, control the second electric drive module to enter the driving mode, and control the third electric drive module to enter the driving mode.

11. The system according to claim 2, characterized in that The system also includes a fourth electric drive module; The fourth electric drive module includes a fourth motor controller, a fourth motor and a third capacitor. The second battery pack is connected to the fourth motor controller, the first end of the fourth motor is connected to the fourth motor controller, and the second end of the fourth motor is connected to the third capacitor in series and then connected to the negative electrode of the second battery pack.

12. The system according to claim 2, characterized in that The system also includes a fifth electric drive module; The fifth electric drive module includes a fifth motor controller and a fifth motor. The second battery pack is connected to the fifth motor controller. The first end of the fifth motor is connected to the fifth motor controller. The second end of the fifth motor is connected to the second motor.

13. A vehicle, characterized in that: A battery self-heating system comprising any one of claims 1 to 12.

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