Battery self-heating system and vehicle

Abstract

A battery self-heating system, comprising a power battery pack (21), a first heating module (22), a second heating module (23), and a controller (24), wherein the power battery pack (21) comprises a first battery group (E1) and a second battery group (E2) connected in series, the first heating module (22) comprises a first heating sub-module (221) and a second heating sub-module (222), the second heating module (23) comprises a third heating sub-module (231) and The battery pack includes a fourth heating sub-module (232), and the controller (24) is configured to control the first heating module (22) and the first battery group (E1) to alternately charge and discharge, and to control the second heating module (23) and the second battery group (E2) to alternately charge and discharge, so that when one of the first battery group (E1) and the second battery group (E2) is in a discharging state, the other of the first battery group (E1) and the second battery group (E2) is in a charging state.

Description

Technical Field

[0001] Cross - reference to Related Applications This disclosure claims priority to Chinese Patent Application No. 202211071491.X, titled "BATTERY SELF - HEATING SYSTEM AND VEHICLE", filed on August 31, 2022. The entire content of the application referenced above is incorporated herein by reference.

[0002] This disclosure relates to electric vehicle technology, and specifically, to a battery self - heating system and a vehicle.

Background Art

[0003] In response to energy conservation and emission reduction, electric vehicles have been attracting increasing attention. When an electric vehicle is in a low - temperature environment, the activity of the positive and negative electrode materials of the battery and the activity of the electrolyte in the battery decrease due to the low temperature, and the charge - discharge performance of the battery will be significantly reduced. To ensure the power of an electric vehicle in a low - temperature environment, the battery of the electric vehicle may be heated to raise the temperature of the battery body to ensure the charge - discharge performance of the battery. In the prior art, battery heating is implemented by alternating charge - discharge between the battery pack and the energy storage element. However, in this charge - discharge process, the terminal voltage fluctuation of the battery pack is large.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of this disclosure is to provide a battery self - heating system and a vehicle to solve the above - mentioned technical problems.

Means for Solving the Problems

[0005] To achieve the above object, a first aspect of this disclosure provides a battery self - heating system applied to a vehicle. The system is

[0006] A power battery pack, comprising a first battery pack and a second battery pack connected in series,

[0007] A first heating module, comprising a first heating submodule and a second heating submodule, wherein the first and second connection terminals of the first heating submodule are connected to the positive and negative terminals of the first battery pack, respectively, the first and second connection terminals of the second heating submodule are connected to the positive and negative terminals of the first battery pack, respectively, and the third connection terminal of the first heating submodule is connected to the third connection terminal of the second heating submodule,

[0008] A second heating module, the second heating module comprising a third heating submodule and a fourth heating submodule, wherein the first and second connection terminals of the third heating submodule are connected to the positive and negative terminals of the second battery pack, respectively, the first and second connection terminals of the fourth heating submodule are connected to the positive and negative terminals of the second battery pack, respectively, and the third connection terminal of the third heating submodule is connected to the third connection terminal of the fourth heating submodule,

[0009] The device includes a controller connected to a first heating module and a second heating module, the controller being configured to control the first heating module and the first battery pack to alternately charge and discharge, the second heating module and the second battery pack to alternately charge and discharge, and to control one of the first battery pack and the second battery pack to be in a charged state when the other of the first battery pack and the second battery pack is in a discharged state.

[0010] Optionally, a first heating submodule includes a first heating winding and a first switch, a second heating submodule includes a second heating winding and a second switch, the first switch includes a first upper switch and a first lower switch connected in series, and the second switch includes a second upper switch and a second lower switch connected in series. The first upper switch is connected to the positive terminal of the first battery pack, the first lower switch is connected to the negative terminal of the first battery pack, the first end of the first heating winding is connected to the connection point between the first upper switch and the first lower switch, the second end of the first heating winding is connected to the first end of the second heating winding, the second end of the second heating winding is connected to the connection point between the second upper switch and the second lower switch, the second upper switch is connected to the positive terminal of the first battery pack, and the second lower switch is connected to the negative terminal of the first battery pack.

[0011] The third heating submodule includes a third heating winding and a third switch, the fourth heating submodule includes a fourth heating winding and a fourth switch, the third switch includes a third upper switch and a third lower switch connected in series, and the fourth switch includes a fourth upper switch and a fourth lower switch connected in series. The third upper switch is connected to the positive terminal of the second battery pack, the third lower switch is connected to the negative terminal of the second battery pack, the first end of the third heating winding is connected to the connection point between the third upper switch and the third lower switch, the second end of the third heating winding is connected to the first end of the fourth heating winding, the second end of the fourth heating winding is connected to the connection point between the fourth upper switch and the fourth lower switch, the fourth upper switch is connected to the positive terminal of the second battery pack, and the fourth lower switch is connected to the negative terminal of the second battery pack.

[0012] Optionally, the first heating winding is a multiphase winding of the vehicle's first drive motor, the first switch is a first multiphase inverter in the first drive motor controller corresponding to the first drive motor, the first upper switch represents the upper bridge arm of the first multiphase inverter, and the first lower switch represents the lower bridge arm of the first multiphase inverter.

[0013] The second heating winding is the multiphase winding of the vehicle's second drive motor, the second switch is the second multiphase inverter in the second drive motor controller corresponding to the second drive motor, the second upper switch represents the upper bridge arm of the second multiphase inverter, and the second lower switch represents the lower bridge arm of the second multiphase inverter.

[0014] The third heating winding is the multiphase winding of the vehicle's third drive motor, the third switch is the third multiphase inverter in the third drive motor controller corresponding to the third drive motor, the third upper switch represents the upper bridge arm of the third multiphase inverter, and the third lower switch represents the lower bridge arm of the third multiphase inverter.

[0015] The fourth heating winding is the multiphase winding of the vehicle's fourth drive motor, the fourth switch is the fourth multiphase inverter in the fourth drive motor controller corresponding to the fourth drive motor, the fourth upper switch represents the upper bridge arm of the fourth multiphase inverter, and the fourth lower switch represents the lower bridge arm of the fourth multiphase inverter.

[0016] Optionally, the controller is configured to control, in a first preset state, to turn on the upper bridge arm of the first polyphase inverter and the lower bridge arm of the second polyphase inverter to discharge the first battery pack, thereby charging the first and second heating windings; to turn on the lower bridge arm of the third polyphase inverter and the upper bridge arm of the fourth polyphase inverter to control the first and second heating windings, thereby charging the second battery pack.

[0017] The controller is configured to control the first and second heating windings by turning on the lower bridge arm of the first polyphase inverter and turning on the upper bridge arm of the second polyphase inverter in a second preset state, thereby charging the first battery pack, and to control the second battery pack by turning on the upper bridge arm of the third polyphase inverter and turning on the lower bridge arm of the fourth polyphase inverter, thereby discharging the second battery pack, thereby charging the first and second heating windings.

[0018] Optionally, the controller may be further configured to control, in the same preset state, the ratio of the current flowing through the first battery pack to the current flowing through the second battery pack to the ratio of the resistance of the second battery pack to the resistance of the first battery pack.

[0019] Optionally, the system further includes a first, second, third, and fourth changeover switch. Both the third and fourth changeover switches are dual-position switches.

[0020] The first changeover switch is located in the connection circuit between the first heating winding and the second heating winding.

[0021] The second changeover switch is located in the connection circuit between the third heating winding and the fourth heating winding.

[0022] The fixed contact of the third changeover switch is connected to the connection end between the lower bridge arm of the first polyphase inverter and the lower bridge arm of the second polyphase inverter; the first movable contact of the third changeover switch is connected separately to the negative terminal of the first battery pack and the positive terminal of the second battery pack; and the second movable contact of the third changeover switch is connected to the negative terminal of the second battery pack.

[0023] The fixed contact of the fourth changeover switch is connected to the connection end between the upper bridge arm of the third multiphase inverter and the upper bridge arm of the fourth multiphase inverter; the first movable contact of the fourth changeover switch is connected to the positive terminal of the first battery pack; and the second movable contact of the fourth changeover switch is connected separately to the negative terminal of the first battery pack and the positive terminal of the second battery pack.

[0024] The first, second, third, and fourth selector switches are connected to a controller, which is configured to control the first and second selector switches to be turned on, to connect the fixed contact of the third selector switch to the first movable contact of the third selector switch, and to connect the fixed contact of the fourth selector switch to the second movable contact of the fourth selector switch, thereby enabling the first and second battery packs to self-heat.

[0025] As an option, the controller controls the first changeover switch and the second changeover switch to be turned off, controls the fixed contact of the third changeover switch to be connected to the second movable contact of the third changeover switch, and controls the fixed contact of the fourth changeover switch to be connected to the first movable contact of the fourth changeover switch, so as to control the first battery pack and the second battery pack to supply power to the first drive motor, the second drive motor, the third drive motor, and the fourth drive motor, and thereby the vehicle is further configured to be driven.

[0026] As an option, the system further includes a first charging switch and a second charging switch.

[0027] The first charging switch is disposed in a connection circuit between the charging port of the vehicle and the positive electrode of the first battery pack.

[0028] The second charging switch is disposed in a connection circuit between the charging port of the vehicle and the negative electrode of the second battery pack.

[0029] When the vehicle is connected to a charging pile, the controller controls the first charging switch and the second charging switch to be turned on, and is further configured to charge the power battery pack while performing self-heating of the first battery pack and the second battery pack.

[0030] As an option, when the vehicle is connected to a charging pile, the controller controls the first charging switch and the second charging switch to be turned on, and controls the third changeover switch and the fourth changeover switch to be turned off, and is further configured to charge the power battery packs separately.

[0031] The second aspect of the present disclosure further provides a vehicle including the battery self-heating system according to any one of the first aspects described above.

[0032] The battery self-heating system provided in this disclosure is applied to a vehicle. The system includes a power battery pack, a drive module, a first heating module, a second heating module, and a controller. The first heating module and the first battery pack are alternately charged and discharged, the second heating module and the second battery pack are alternately charged and discharged, and one of the first and second battery packs is charged when the other of the first and second battery packs is discharged. In this way, the voltage fluctuations of the first battery pack and the voltage fluctuations of the second battery pack during self-heating cancel each other out, resulting in small terminal voltage fluctuations of the power battery pack, thereby preventing charging failures in the vehicle.

[0033] Other features and advantages of this disclosure will be described in detail in subsequent specific embodiments.

[0034] The accompanying drawings are used to provide a further understanding of this disclosure, constitute part of this specification, and are used to illustrate this disclosure together with the following specific embodiments, but are not intended to limit this disclosure. [Brief explanation of the drawing]

[0035] [Figure 1] This is a schematic diagram of a conventional battery self-heating circuit. [Figure 2] This is a schematic diagram of a battery self-heating system according to one embodiment of the present disclosure. [Figure 3] This is a schematic diagram of another battery self-heating system according to one embodiment of the present disclosure. [Figure 4] This is a schematic diagram of another battery self-heating system according to one embodiment of the present disclosure. [Figure 5] This is a circuit diagram of a battery self-heating system according to one embodiment of the present disclosure. [Figure 6] This is a schematic diagram of the current direction when a battery self-heating system according to one embodiment of the present disclosure is in operation. [Figure 7] This is a schematic diagram of the current direction when another battery self-heating system according to one embodiment of the present disclosure is in operation. [Figure 8] This is a circuit diagram of another battery self-heating system according to one embodiment of the present disclosure. [Figure 9] This is a schematic diagram of the current direction when another battery self-heating system according to one embodiment of the present disclosure is in operation. [Figure 10] This is a schematic diagram of the current direction when another battery self-heating system according to one embodiment of the present disclosure is in operation. [Modes for carrying out the invention]

[0036] The following describes in detail specific embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are used solely to describe and explain the present disclosure and are not intended to limit the present disclosure.

[0037] It should be understood that the steps recorded in the embodiments of the methods in this disclosure may be performed in different orders and / or in parallel. In addition, embodiments of the methods may include additional steps and / or omit steps that are performed and shown. The scope of this disclosure is not limited to these embodiments. As used herein, the term “comprise” and its variations mean “comprise, but not limited to.” The term “based on” means “based at least in part.” The term “one embodiment” means “at least one embodiment.” The term “another embodiment” means “at least one other embodiment.” The term “several embodiments” means “at least several embodiments.” Relevant definitions of other terms are given below.

[0038] It should be noted that concepts such as “first” and “second” as used in this disclosure are used to distinguish different devices, modules, or units, and are not used to limit the order or independence of the functions performed by these devices, modules, or units. It should be noted that the modifiers “one” and “many” as used in this disclosure are illustrative, not restrictive. Those skilled in the art will understand that the modifiers should be understood as “one or more” unless the context explicitly indicates otherwise.

[0039] In response to energy savings and emission reductions, electric vehicles are being chosen by an increasing number of users. To improve the driving performance of electric vehicles, multi-motor electric vehicles, known for their powerful performance, are gradually attracting public attention. Powerful performance requires good battery charge and discharge performance. However, when electric vehicles are in low-temperature environments, especially below -10°C, the activity of the positive and negative electrode materials of the battery, as well as the activity of the electrolyte in the battery, decreases due to the low temperature, resulting in a significant decrease in the battery's charge and discharge performance. To ensure power for electric vehicles in low-temperature environments, the electric vehicle's battery may be heated to raise the temperature of the battery body to ensure battery charge and discharge performance.

[0040] Currently, batteries can be heated in two ways: external heating and internal heating. In the external heating method, an additional heating device is added to heat the battery. This heating method is costly due to the addition of the heating device, and the heating efficiency is low because heat dissipation is fast externally, and there is a certain distance between the location where the external temperature rises and the internal battery. However, the principle of the internal heating method is to generate heat through the internal resistance of the battery, mainly by using the periodic charging and discharging of the battery. For example, as shown in Figure 1, the battery self-heating circuit includes a battery 11, a capacitor 12, an inverter 13, and a motor winding 14. The battery 11, capacitor 12, and inverter 13 are connected in parallel. By using the inverter 13 and the motor winding 14, oscillating heating is performed on the battery 11. In addition, during oscillating heating, the battery 11 is in an alternating charging and discharging state. Therefore, the battery voltage fluctuations are large. However, these fluctuations can damage the battery and shorten its service life.

[0041] In addition, when a charging pile is connected for DC charging while the battery is self-heating, the battery is limited by the heating principle of battery self-heating. Specifically, when a large current flows through the battery, the battery's internal resistance generates heat, heating the battery. In other words, to generate more heat, a larger self-heating current is required, assuming the battery's internal resistance and heating time remain constant. The battery voltage fluctuation ΔU is equal to I × Rcell. Assuming the total internal resistance Rcell of the battery remains constant, the larger the battery current I, the larger the battery voltage fluctuation ΔU. This fluctuation can prevent the charging pile from tracking the battery voltage in real time during DC charging, potentially leading to a gun jump or charging failure. Furthermore, due to topology limitations, the current flowing through the motor windings simultaneously consists of the current flowing into the motor windings and the current flowing out of the motor windings. In other words, the heating current may be limited to only the current limit of the single-phase winding. As a result, the heating power is limited.

[0042] In view of this, the present disclosure provides a battery self-heating system and a vehicle to solve the aforementioned technical problems.

[0043] The technical solutions of this disclosure are described in the following detailed embodiments.

[0044] Embodiments of this disclosure provide a battery self-heating system applicable to a vehicle. Referring to Figure 2, the battery self-heating system includes a power battery pack 21, a first heating module 22, a second heating module 23, and a controller 24.

[0045] The power battery pack 21 includes a first battery pack E1 and a second battery pack E2 connected in series. The first heating module 22 includes a first heating submodule 221 and a second heating submodule 222, the first and second connection terminals of the first heating submodule 221 being connected to the positive and negative terminals of the first battery pack E1, respectively, the first and second connection terminals of the second heating submodule 222 being connected to the positive and negative terminals of the first battery pack E1, respectively, and the third connection terminal of the first heating submodule 221 being connected to the third connection terminal of the second heating submodule 222. The second heating module 23 includes a third heating submodule 231 and a fourth heating submodule 232, wherein the first and second connection terminals of the third heating submodule 231 are connected to the positive and negative terminals of the second battery pack E2, respectively, and the first and second connection terminals of the fourth heating submodule 232 are connected to the positive and negative terminals of the second battery pack E2, respectively, and the third connection terminal of the third heating submodule 231 is connected to the third connection terminal of the fourth heating submodule 232. The controller 24 is connected to the first heating module 22 and the second heating module 23. The controller 24 is configured to control the first heating module 22 and the first battery pack E1 to alternately charge and discharge, and to control the second heating module 23 and the second battery pack E2 to alternately charge and discharge, and to control one of the first battery pack E1 and the second battery pack E2 to be in a charging state when the other of the first battery pack E1 and the second battery pack E2 is in a discharge state.

[0046] When the aforementioned battery self-heating system is used for battery self-heating, the voltage fluctuations of the first battery pack and the voltage fluctuations of the second battery pack cancel each other out, resulting in small terminal voltage fluctuations of the power battery pack, thereby preventing charging failures in the vehicle.

[0047] To enable those skilled in the art to better understand the battery self-heating systems provided in this disclosure, the steps described above are illustrated in more detail using the following example.

[0048] In a possible manner, referring to Figure 3, the first heating submodule 221 includes a first heating winding 31 and a first switch 32, the second heating submodule 222 includes a second heating winding 33 and a second switch 34, the first switch 32 includes a first upper switch 321 and a first lower switch 322 connected in series, and the second switch 34 includes a second upper switch 341 and a second lower switch 342 connected in series. The first upper switch 321 is connected to the positive terminal of the first battery pack E1, the first lower switch 322 is connected to the negative terminal of the first battery pack E1, the first end of the first heating winding 31 is connected to the connection point between the first upper switch 321 and the first lower switch 322, the second end of the first heating winding 31 is connected to the first end of the second heating winding 33, the second end of the second heating winding 33 is connected to the connection point between the second upper switch 341 and the second lower switch 342, the second upper switch 341 is connected to the positive terminal of the first battery pack E1, and the second lower switch 342 is connected to the negative terminal of the first battery pack E1.

[0049] In addition, the third heating submodule 231 includes a third heating winding 35 and a third switch 36, the fourth heating submodule 232 includes a fourth heating winding 37 and a fourth switch 38, the third switch 36 includes a third upper switch 361 and a third lower switch 362 connected in series, and the fourth switch 38 includes a fourth upper switch 381 and a fourth lower switch 382 connected in series. The third upper switch 361 is connected to the positive terminal of the second battery pack E2, the third lower switch 362 is connected to the negative terminal of the second battery pack E2, the first end of the third heating winding 35 is connected to the connection point between the third upper switch 361 and the third lower switch 362, the second end of the third heating winding 35 is connected to the first end of the fourth heating winding 37, the second end of the fourth heating winding 37 is connected to the connection point between the fourth upper switch 381 and the fourth lower switch 382, ​​the fourth upper switch 381 is connected to the positive terminal of the second battery pack E2, and the fourth lower switch 382 is connected to the negative terminal of the second battery pack E2.

[0050] In possible ways, for vehicles with multiple motors, self-heating may be performed on the power battery pack by using multiple drive motor controllers and multiple drive motors within the vehicle. Referring to Figure 4, a vehicle with multiple three-phase motors is used as an example. The power battery pack is divided into two battery packs, and four groups of drive motor controllers and drive motors are selected. The drive motor controllers and drive motors in one group are used as the first switch and first heating winding of the first heating submodule, respectively. The drive motor controllers and drive motors in one group are used as the second switch and second heating winding of the second heating submodule, respectively. The drive motor controllers and drive motors in one group are used as the third switch and third heating winding of the third heating submodule, respectively. The drive motor controllers and drive motors in one group are used as the fourth switch and fourth heating winding of the fourth heating submodule, respectively.

[0051] Referring to Figure 5, the first heating winding is the multiphase winding of the vehicle's first drive motor 1, the first switch is the first multiphase inverter in the first drive motor controller 2 corresponding to the first drive motor 1, the first upper switch represents the upper bridge arm of the first multiphase inverter, and the first lower switch represents the lower bridge arm of the first multiphase inverter. The second heating winding is the multiphase winding of the vehicle's second drive motor 3, the second switch is the second multiphase inverter in the second drive motor controller 4 corresponding to the second drive motor 3, the second upper switch represents the upper bridge arm of the second multiphase inverter, and the second lower switch represents the lower bridge arm of the second multiphase inverter. The third heating winding is the multiphase winding of the vehicle's third drive motor 5, the third switch is the third multiphase inverter in the third drive motor controller 6 corresponding to the third drive motor 5, the third upper switch represents the upper bridge arm of the third multiphase inverter, and the third lower switch represents the lower bridge arm of the third multiphase inverter. The fourth heating winding is the multiphase winding of the vehicle's fourth drive motor 7, the fourth switch is the fourth multiphase inverter in the fourth drive motor controller 8 corresponding to the fourth drive motor 7, the fourth upper switch represents the upper bridge arm of the fourth multiphase inverter, and the fourth lower switch represents the lower bridge arm of the fourth multiphase inverter.

[0052] In possible ways, the controller is configured to control the upper bridge arm of the first polyphase inverter to be turned on and the lower bridge arm of the second polyphase inverter to be turned on in a first preset state, thereby discharging the first battery pack and charging the first and second heating windings; and to control the lower bridge arm of the third polyphase inverter to be turned on and the upper bridge arm of the fourth polyphase inverter to control the first and second heating windings and thereby charging the second battery pack.

[0053] Furthermore, the controller is configured to control the first and second heating windings by turning on the lower bridge arm of the first polyphase inverter and turning on the upper bridge arm of the second polyphase inverter in a second preset state, thereby charging the first battery pack, and to control the second battery pack by turning on the upper bridge arm of the third polyphase inverter and turning on the lower bridge arm of the fourth polyphase inverter, thereby discharging the second battery pack, thereby charging the first and second heating windings.

[0054] For example, in the first preset state, referring to Figure 6, the upper bridge arm of the first drive motor controller 2 is turned on and the lower bridge arm of the first drive motor controller 2 is turned off. The upper bridge arm of the second drive motor controller 4 is turned off and the lower bridge arm of the second drive motor controller 4 is turned on. The first battery pack E1 charges the multiphase windings of the first drive motor 1 via the upper bridge arm of the first drive motor controller 2. The charging current flows through the second drive motor 3 and charges the multiphase windings of the second drive motor 3, and the charging current finally flows back to the first battery pack E1 via the lower bridge arm of the second drive motor controller 4. In this case, the first battery pack E1 is discharged and its voltage drops. The upper bridge arm of the third drive motor controller 6 is turned off, and the lower bridge arm of the third drive motor controller 6 is turned on or off (due to the characteristic that the diode is turned on in one direction, current passes through the parasitic diode of the lower bridge arm when the lower bridge arm is turned off, and the same applies hereafter). The upper bridge arm of the fourth drive motor controller 8 is turned on or off, and the lower bridge arm of the fourth drive motor controller 8 is turned off. The multiphase windings of the third drive motor 5 and the multiphase windings of the fourth drive motor 7 charge the second battery pack E2 by using the stored energy via the upper bridge arm of the fourth drive motor controller 8. In this case, the second battery pack E2 is charged and the voltage rises.

[0055] For example, in the second preset state, referring to Figure 7, the upper bridge arm of the first drive motor controller 2 is turned off, and the lower bridge arm of the first drive motor controller 2 is turned on or off. The upper bridge arm of the second drive motor controller 4 is turned on or off, and the lower bridge arm of the second drive motor controller 4 is turned off. The multiphase windings of the first drive motor 1 and the multiphase windings of the second drive motor 3 charge the first battery pack E1 by using the stored energy via the upper bridge arm of the second drive motor controller 4. In this case, the first battery pack E1 is charged and the voltage rises. The upper bridge arm of the third drive motor controller 6 is turned on, and the lower bridge arm of the third drive motor controller 6 is turned off. The upper bridge arm of the fourth drive motor controller 8 is turned off, and the lower bridge arm of the fourth drive motor controller 8 is turned on. The second battery pack E2 charges the multiphase windings of the third drive motor 5 via the upper bridge arm of the third drive motor controller 6. The charging current flows through the fourth drive motor 7, charging the multiphase windings of the fourth drive motor 7, and the charging current eventually flows back to the second battery pack E2 via the lower bridge arm of the fourth drive motor controller 8. In this case, the second battery pack E2 is discharged and its voltage drops.

[0056] It is worth noting that in the first preset state, the voltage of the first battery pack E1 continues to decrease, with a decrease range ΔU1 equal to I1 × Rcell1. The voltage of the second battery pack E2 continues to increase, with an increase range ΔU2 equal to I2 × Rcell2. In the second preset state, the voltage of the first battery pack E1 continues to increase, with an increase range ΔU1 equal to I1 × Rcell1. The voltage of the second battery pack E2 continues to decrease, with a decrease range ΔU2 equal to I2 × Rcell2. Therefore, the current I1 and resistor Rcell1 of the first battery pack and the current I2 and resistor Rcell2 of the second battery pack are controlled so that the total voltage fluctuation of the power battery pack can be within a preset voltage fluctuation range, e.g., -0.5V to 0.5V. The specific preset voltage fluctuation range may be determined according to requirements and is not limited herein. Of course, assuming that Rcell1 is equal to Rcell2, the total voltage fluctuation of the power battery pack can be zero, as long as it is guaranteed that I1 is equal to I2. In this way, energy is periodically charged and discharged between the power battery pack and the motor windings through the cycle of moving back and forth between the first preset state and the second preset state, thereby achieving battery self-heating.

[0057] Where possible, the controller may be further configured to control, in the same preset state, the ratio of the current flowing through the first battery pack to the current flowing through the second battery pack to the ratio of the resistance of the second battery pack to the resistance of the first battery pack.

[0058] For example, from the aforementioned charge-discharge process between the first and second battery packs while the batteries are self-heating, it can be seen that the voltage fluctuations are related to the current and the resistance of the batteries. The resistance of the battery packs is determined when the battery packs are divided. Therefore, the total voltage fluctuation of the power battery packs can be kept within a preset voltage fluctuation range by adjusting the current of the battery packs. For example, if a power battery pack is divided into two battery packs having the same number of battery cores, then Rcell1 is equal to Rcell2. If the total voltage fluctuation of the power battery packs needs to be controlled to be zero, then I1 can be controlled to be equal to I2. In another example, a power battery pack is divided into two battery packs having different numbers of battery cores. If the total voltage fluctuation of the power battery packs needs to be controlled to be zero, then I1 / I2 can be controlled to be equal to Rcell2 / Rcell1. In other words, if the ratio of the current flowing through the first battery pack to the current flowing through the second battery pack is equal to the ratio of the resistance of the second battery pack to the resistance of the first battery pack, then the total voltage fluctuation of the power battery pack is equal to zero. Correspondingly, if it is necessary to control the total voltage fluctuation of the power battery pack so that it is within a preset voltage fluctuation range, the current in the battery packs into which the power battery pack is divided may be controlled based on a control relationship in which the current is smaller as the resistance of the battery pack increases. Further details may be determined based on requirements and tests, and are not limited to those in this disclosure.

[0059] In addition, the power battery pack may be divided into, for example, three battery packs, four battery packs, etc., with one heating module assigned to each battery pack. The number of battery packs and the number of battery cores within each battery pack are not limited in this disclosure, as long as the total voltage fluctuation of the power battery pack is within a preset voltage fluctuation range. For example, the resistance of each battery core within the power battery pack is equal. The number of battery cores included in the battery pack may be N1, N2, N3, ..., and N n Assuming this is the case, the self-heating current of the battery pack is I1 / I2 / I3 / ... / I n is N n The following conditions must be met: / … / N3 / N2 / N1 is equal. Of course, each battery pack may, alternatively, be connected in parallel with a number of heating modules, as long as the sum of the currents of the heating modules is controlled to be equal to the current of the battery pack. The currents of heating modules connected in parallel within the same battery pack may or may not be equal, and this is not limited in this disclosure. In addition, compared to the prior art in which the heating current may be only the current limit of the single-phase winding, in the battery self-heating systems provided in embodiments of this disclosure, by adding a drive motor and a drive motor controller, the maximum heating current can be the current limit of the N-phase winding. For example, in the three-phase drive motor of Figure 5, the maximum heating current is the current limit of the three-phase winding, which is three times the heating current of the prior art, and as a result the efficiency of battery self-heating is improved.

[0060] Where possible, switches may be added to the circuit to control the on / off state of the circuit. Referring to Figure 5, the system further includes a first changeover switch K1, a second changeover switch K2, a third changeover switch K3, and a fourth changeover switch K4. Both the third changeover switch K3 and the fourth changeover switch K4 are two-position switches.

[0061] The first changeover switch K1 is located in the connection circuit between the first heating winding (multiphase winding of the first drive motor 1) and the second heating winding (multiphase winding of the second drive motor 3). The second changeover switch K2 is located in the connection circuit between the third heating winding (multiphase winding of the third drive motor 5) and the fourth heating winding (multiphase winding of the fourth drive motor 7). The fixed contact a of the third changeover switch K3 is connected to the connection end between the lower bridge arm of the first multiphase inverter (in the first drive motor controller 2) and the lower bridge arm of the second multiphase inverter (in the second drive motor controller 4). The first movable contact b of the third changeover switch K3 is connected separately to the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2. The second movable contact c of the third changeover switch K3 is connected to the negative terminal of the second battery pack E2. The fixed contact a of the fourth changeover switch K4 is connected to the connection terminal between the upper bridge arm of the third multiphase inverter (in the third drive motor controller 6) and the upper bridge arm of the fourth multiphase inverter (in the fourth drive motor controller 8), the first movable contact b of the fourth changeover switch K4 is connected to the positive terminal of the first battery pack E1, and the second movable contact c of the fourth changeover switch K4 is connected separately to the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2.

[0062] Furthermore, the first changeover switch K1, the second changeover switch K2, the third changeover switch K3, and the fourth changeover switch K4 are connected to a controller, which is configured to control the first changeover switch K1 and the second changeover switch K2 to be turned on, to connect the fixed contact a of the third changeover switch K3 to the first movable contact b of the third changeover switch K3, and to connect the fixed contact a of the fourth changeover switch K4 to the second movable contact c of the fourth changeover switch K4, thereby enabling the first battery pack E1 and the second battery pack E2 to self-heat. For details, please refer to Figures 6 and 7.

[0063] In possible ways, the controller is further configured to control the first battery pack E1 and the second battery pack E2 to supply power to the first drive motor, the second drive motor, the third drive motor, and the fourth drive motor, thereby driving the vehicle, by controlling the first changeover switch K1 and the second changeover switch K2 to be turned off, by controlling the fixed contact a of the third changeover switch K3 to the second movable contact c of the third changeover switch K3, and by controlling the fixed contact a of the fourth changeover switch K4 to the first movable contact b of the fourth changeover switch K4.

[0064] For example, the first changeover switch K1 and the second changeover switch K2 are controlled to be turned off, the fixed contact a of the third changeover switch K3 is controlled to be connected to the second movable contact b of the third changeover switch K3, and the fixed contact a of the fourth changeover switch K4 is controlled to be connected to the first movable contact b of the fourth changeover switch K4. In this case, the first drive motor and the first drive motor controller, the second drive motor and the second drive motor controller, the third drive motor and the third drive motor controller, and the fourth drive motor and the fourth drive motor controller each constitute a drive module and are connected separately in parallel to the power battery pack. For the operation process of the drive motors and drive motor controllers in drive mode, please refer to the prior art, as further details are not described again in this disclosure.

[0065] Where possible, the system further includes a first charging switch K5 and a second charging switch K6. The first charging switch K5 is located in the connection circuit between the vehicle's charging port and the positive terminal of the first battery pack E1, and the second charging switch K6 is located in the connection circuit between the vehicle's charging port and the negative terminal of the second battery pack E2. The controller is further configured to charge the power battery packs while allowing the first battery pack E1 and the second battery pack E2 to self-heat when the vehicle is connected to the charging pile.

[0066] For example, when the vehicle requires DC charging and battery self-heating is performed, the first charging switch K5, the second charging switch K6, the first changeover switch K1, and the second changeover switch K2 are controlled to be turned on, the fixed contact a of the third changeover switch K3 is controlled to be connected to the first movable contact b of the third changeover switch K3, and the fixed contact a of the fourth changeover switch K4 is controlled to be connected to the second movable contact c of the fourth changeover switch K4. Figure 9 shows the bridge arm state and current direction of the first and second heating modules and the current direction of DC charging in the first preset state. For the bridge arm state and current direction of the first and second heating modules in the second preset state, please refer to Figure 7, as further details are not described again in this disclosure. In this way, the power battery pack is charged while the self-heating of the first battery pack E1 and the second battery pack E2 is being performed. The voltage fluctuations of the first battery pack and the second battery pack cancel each other out, resulting in small terminal voltage fluctuations in the power battery packs, thereby preventing charging failures in the vehicle.

[0067] In possible ways, the controller may be further configured to charge the power battery packs separately by controlling the first and second charging switches to turn on and the third and fourth toggle switches to turn off when the vehicle is connected to the charging pile.

[0068] For example, referring to Figure 10, when the vehicle requires DC charging, the first charging switch K5, and Second charging switch K6 Turn it on , first changeover switch K1, and second changeover switch K2 Turn it off The third changeover switch K3 is controlled so that its fixed contact a is not connected to the first movable contact b and the second movable contact c of the third changeover switch K3, and the fourth changeover switch K4 is controlled so that its fixed contact a is not connected to the first movable contact b and the second movable contact c of the fourth changeover switch K4.

[0069] It is worth noting that in multi-motor vehicles, some drive motor controllers and drive motors are used as heating modules to perform self-heating in the power battery pack. In other words, the drive motor controllers and drive motors may be configured to drive the vehicle and, furthermore, to perform self-heating in the power battery pack without the addition of another element or heating device, thereby satisfying the requirement to heat the power battery pack and reducing costs. However, in other single-motor or dual-motor vehicles, the self-heating function of the power battery pack may be achieved by adding switches and windings as heating modules. Of course, in multi-motor vehicles, switches and windings may be added as heating modules, but this is not limited to the foregoing.

[0070] For example, the switch may consist of a single-phase bridge arm or a multi-phase bridge arm, or it may consist of another switch element having the function of turning the circuit on and off. The winding may be a separate single-phase winding or a multi-phase winding, or it may be a winding in a single-phase motor or a multi-phase motor. This is not limited to the present disclosure. In addition, multiple heating modules may be connected to the same battery pack, and each heating module may have the same bridge arm state and current direction in the same preset state. In addition, for heating modules that are not involved in driving the vehicle, a six-phase bridge arm and a six-phase motor may be used to replace the two three-phase bridge arms and two three-phase motors shown in Figure 5.

[0071] The controller may be a control unit in a drive motor controller or an electronic device mounted in the vehicle. This is not limited to the present disclosure. A temperature sensor may also be located near the power battery pack to transmit the collected battery temperature to the controller in real time. If the battery temperature is below a preset threshold, the controller automatically controls the power battery pack to perform self-heating. A heating button may also be provided in the vehicle. For example, an onboard display screen may alert the driver when the power battery pack is in a low temperature state. The driver can send a signal to the controller to initiate self-heating via a heating button set on the onboard display screen. After receiving the signal, the controller controls the power battery pack to perform self-heating. This is not limited to the present disclosure.

[0072] In addition, in the process of controlling the battery pack to be charged and discharged alternately, one or more of a number of bridge arms or switches can be controlled to be turned on, thereby controlling some of the windings involved in self-heating. For example, in Figure 6, one of the three upper bridge arms of the first drive motor controller 2 is selected to be turned on, as a result the first battery pack E1 can be discharged and the windings connected to the first battery pack of the first drive motor 1 can be charged. Generally, the more windings involved in self-heating, the higher the efficiency of self-heating. In other possible embodiments, the number of windings involved in self-heating may be controlled according to the battery temperature. For example, the lower the battery temperature, the more windings there are. This is not limited to the present disclosure.

[0073] Based on the same inventive concept, embodiments of the present disclosure further provide a vehicle including the battery self-heating system described above. Through the battery self-heating system, the vehicle's battery is heated, its temperature rises, and the battery's performance in low-temperature environments is ensured. In addition, if DC charging is performed in the vehicle, self-heating may also be performed on the power battery pack.

[0074] Preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the embodiments described above, and many simple modifications may be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and these simple modifications are within the scope of the protection of the present disclosure.

[0075] In addition, it should be noted that the specific technical features described in the particular embodiments described above may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, various possible combinations are not further described in this disclosure.

[0076] In addition, the various embodiments of this disclosure may be combined in any way without departing from the spirit of this disclosure, and such combinations shall still be deemed to be the same as those disclosed in this disclosure.

Claims

1. A battery self-heating system applied to a vehicle, wherein the system is A power battery pack (21), wherein the power battery pack (21) comprises a first battery pack (E1) and a second battery pack (E2) connected in series, The first heating module (22) comprises a first heating submodule (221) and a second heating submodule (222), wherein the first and second connection terminals of the first heating submodule (221) are connected to the positive and negative terminals of the first battery pack (E1), respectively, the first and second connection terminals of the second heating submodule (222) are connected to the positive and negative terminals of the first battery pack (E1), respectively, and the third connection terminal of the first heating submodule (221) is connected to the third connection terminal of the second heating submodule (222). The second heating module (23) comprises a third heating submodule (231) and a fourth heating submodule (232), wherein the first and second connection terminals of the third heating submodule (231) are connected to the positive and negative terminals of the second battery pack (E2), respectively, the first and second connection terminals of the fourth heating submodule are connected to the positive and negative terminals of the second battery pack (E2), respectively, and the third connection terminal of the third heating submodule (231) is connected to the third connection terminal of the fourth heating submodule (232). A system comprising a controller (24) connected to the first heating module (22) and the second heating module (23), wherein the controller (24) controls the first heating module (22) and the first battery pack (E1) to alternately charge and discharge, controls the second heating module (23) and the second battery pack (E2) to alternately charge and discharge, and controls one of the first battery pack (E1) and the second battery pack (E2) to be in a charging state when the other of the first battery pack (E1) and the second battery pack (E2) is in a discharge state.

2. The first heating submodule (221) comprises a first heating winding (31) and a first switch (32), the second heating submodule (222) comprises a second heating winding (33) and a second switch (34), the first switch (32) comprises a first upper switch (321) and a first lower switch (322) connected in series, the second switch (34) comprises a second upper switch (341) and a second lower switch (342) connected in series, the first upper switch (321) is connected to the positive terminal of the first battery pack (E1), and the first lower switch (322) is connected to the first battery The first heating winding (31) is connected to the negative terminal of the re-pack (E1), the first end of the first heating winding (31) is connected to the connection point between the first upper switch (321) and the first lower switch (322), the second end of the first heating winding (31) is connected to the first end of the second heating winding (33), the second end of the second heating winding (33) is connected to the connection point between the second upper switch (341) and the second lower switch (342), the second upper switch (341) is connected to the positive terminal of the first battery pack (E1), and the second lower switch (342) is connected to the negative terminal of the first battery pack (E1). The third heating submodule (231) comprises a third heating winding (35) and a third switch (36), the fourth heating submodule (232) comprises a fourth heating winding (37) and a fourth switch (38), the third switch (36) comprises a third upper switch (361) and a third lower switch (362) connected in series, the fourth switch (38) comprises a fourth upper switch (381) and a fourth lower switch (382) connected in series, the third upper switch (361) is connected to the positive terminal of the second battery pack (E2), and the third lower switch (362) is connected to the second battery pack (E2). The system according to claim 1, wherein the first end of the third heating winding (35) is connected to the negative terminal of the second battery pack (E2), the second end of the third heating winding (35) is connected to the first end of the fourth heating winding (37), the second end of the fourth heating winding (37) is connected to the connection point between the fourth upper switch (381) and the fourth lower switch (382), the fourth upper switch (381) is connected to the positive terminal of the second battery pack (E2), and the fourth lower switch (382) is connected to the negative terminal of the second battery pack (E2).

3. The first heating winding (31) is a multiphase winding of the first drive motor (1) of the vehicle, the first switch (32) is a first multiphase inverter in the first drive motor controller (2) corresponding to the first drive motor (1), the first upper switch (321) represents the upper bridge arm of the first multiphase inverter, and the first lower switch (322) represents the lower bridge arm of the first multiphase inverter. The second heating winding (33) is a multiphase winding of the second drive motor (3) of the vehicle, the second switch (34) is a second multiphase inverter in the second drive motor controller (4) corresponding to the second drive motor (3), the second upper switch (341) represents the upper bridge arm of the second multiphase inverter, and the second lower switch (342) represents the lower bridge arm of the second multiphase inverter. The third heating winding (35) is a multiphase winding of the third drive motor (5) of the vehicle, the third switch (36) is a third multiphase inverter in the third drive motor controller (6) corresponding to the third drive motor (5), the third upper switch (361) represents the upper bridge arm of the third multiphase inverter, and the third lower switch (362) represents the lower bridge arm of the third multiphase inverter. The system according to claim 2, wherein the fourth heating winding (37) is a multiphase winding of the fourth drive motor (7) of the vehicle, the fourth switch (38) is a fourth multiphase inverter in the fourth drive motor controller (8) corresponding to the fourth drive motor (7), the fourth upper switch (381) represents the upper bridge arm of the fourth multiphase inverter, and the fourth lower switch (382) represents the lower bridge arm of the fourth multiphase inverter.

4. The controller (24) is configured to, in a first preset state, control the upper bridge arm of the first polyphase inverter to be turned on, control the lower bridge arm of the second polyphase inverter to be turned on, thereby discharging the first battery pack (E1), thereby energizing the first heating winding (31) and the second heating winding (33), control the lower bridge arm of the third polyphase inverter to be turned on, control the upper bridge arm of the fourth polyphase inverter to control the third heating winding (35) and the fourth heating winding (37), thereby charging the second battery pack (E2). The system according to claim 3, wherein the controller (24) is configured to control the lower bridge arm of the first polyphase inverter to be turned on and the upper bridge arm of the second polyphase inverter to be turned on in a second preset state, thereby controlling the first heating winding (31) and the second heating winding (33) to charge the first battery pack (E1), and to control the upper bridge arm of the third polyphase inverter to be turned on and the lower bridge arm of the fourth polyphase inverter to be turned on, thereby discharging the second battery pack (E2), thereby energizing the third heating winding (35) and the fourth heating winding (37).

5. The system according to claim 4, wherein the controller (24) is further configured to control, in both the first preset state and the second preset state, the ratio of the current flowing through the first battery pack (E1) to the current flowing through the second battery pack (E2) is equal to the ratio of the resistance of the second battery pack (E2) to the resistance of the first battery pack (E1).

6. The system further comprises a first changeover switch (K1), a second changeover switch (K2), a third changeover switch (K3), and a fourth changeover switch (K4), wherein both the third changeover switch (K3) and the fourth changeover switch (K4) are two-position switches. The first changeover switch (K1) is located in the connection circuit between the first heating winding (31) and the second heating winding (33). The second changeover switch (K2) is located in the connection circuit between the third heating winding (35) and the fourth heating winding (37). The fixed contact of the third changeover switch (K3) is connected to the connection terminal between the lower bridge arm of the first multiphase inverter and the lower bridge arm of the second multiphase inverter, the first movable contact of the third changeover switch (K3) is connected separately to the negative terminal of the first battery pack (E1) and the positive terminal of the second battery pack (E2), and the second movable contact of the third changeover switch (K3) is connected to the negative terminal of the second battery pack (E2). The fixed contact of the fourth changeover switch (K4) is connected to the connection end between the upper bridge arm of the third multiphase inverter and the upper bridge arm of the fourth multiphase inverter, the first movable contact of the fourth changeover switch (K4) is connected to the positive terminal of the first battery pack (E1), and the second movable contact of the fourth changeover switch (K4) is connected separately to the negative terminal of the second battery pack (E1) and the positive terminal of the second battery pack (E2). The system according to claim 3, wherein the first changeover switch (K1), the second changeover switch (K2), the third changeover switch (K3), and the fourth changeover switch (K4) are connected to the controller (24), and the controller (24) is configured to control the first changeover switch (K1) and the second changeover switch (K2) to be turned on, to control the fixed contact of the third changeover switch (K3) to be connected to the first movable contact of the third changeover switch (K3), and to control the fixed contact of the fourth changeover switch (K4) to be connected to the second movable contact of the fourth changeover switch (K4), thereby enabling the first battery pack (E1) and the second battery pack (E2) to self-heat.

7. The controller (24) is further configured to control the first changeover switch (K1) and the second changeover switch (K2) to be turned off, to control the fixed contact of the third changeover switch (K3) to be connected to the second movable contact of the third changeover switch (K3), and to control the fixed contact of the fourth changeover switch (K4) to be connected to the first movable contact of the fourth changeover switch (K4), thereby controlling the first battery pack (E1) and the second battery pack (E2) to supply power to the first drive motor (1), the second drive motor (3), the third drive motor (5), and the fourth drive motor (7), thereby driving the vehicle. The system according to claim 6.

8. The device further comprises a first charging switch (K5) and a second charging switch (K6), The first charging switch (K5) is located in the connection circuit between the vehicle's charging port and the positive terminal of the first battery pack (E1). The second charging switch (K6) is located in the connection circuit between the charging port of the vehicle and the negative terminal of the second battery pack (E2). The system according to claim 6, wherein the controller (24) is further configured to charge the power battery pack (21) while the first battery pack (E1) and the second battery pack (E2) self-heat when the vehicle is connected to a charging pile.

9. The system according to claim 8, further configured such that when the vehicle is connected to the charging pile, the controller (24) controls the first charging switch (K5) and the second charging switch (K6) to be turned on, and controls the third changeover switch (K3) and the fourth changeover switch (K4) such that the fixed contact (a) of the third changeover switch (K3) is not connected to either the first movable contact (b) or the second movable contact (c) of the third changeover switch (K3), and the fixed contact (a) of the fourth changeover switch (K4) is not connected to either the first movable contact (b) or the second movable contact (c) of the fourth changeover switch (K4), thereby charging the power battery pack (21).

10. A vehicle comprising the battery self-heating system according to any one of claims 1 to 9.

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