Battery charging and discharging apparatus and new energy vehicle

Abstract

A battery charging and discharging apparatus, comprising: a charging interface (100), comprising a positive electrode connection terminal and a negative electrode connection terminal; an electric drive assembly (200), comprising a motor (M), a first bridge arm (210) and a second bridge arm (220), each phase line of the motor (M) being connected to a first end (210) of the first bridge arm and a first end of the second bridge arm (220), a neutral line of the motor (M) being connected to the positive electrode connection terminal or the negative electrode connection terminal, and a second end of the first bridge arm (210) being connected to the positive electrode connection terminal, and / or a second end of the second bridge arm (220) being connected to the negative electrode connection terminal; and a battery pack interface (300), of which a first connection terminal for connecting to a positive electrode of a power battery pack is connected to the neutral line of the motor (M), and a second connection terminal for connecting to a negative electrode of the power battery pack is connected to the second end of the second bridge arm (220). When an output voltage of a charging pile is less than a charging voltage of a battery, the battery charging and discharging apparatus can still meet the charging requirements of the battery. Further provided is a new energy vehicle.

Description

Battery charging and discharging devices and new energy vehicles

[0001] This application claims priority to Chinese patent application filed on February 28, 2025, with application number 202510243503X and title "Battery Charging and Discharging Device and New Energy Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of new energy vehicles, specifically to a battery charging and discharging device and a new energy vehicle. Background Technology

[0003] New energy vehicles are a rapidly developing mode of transportation in recent years, attracting widespread attention for their environmentally friendly and energy-saving characteristics. New energy vehicles mainly include pure electric vehicles and plug-in hybrid electric vehicles, which generally use electricity as their primary power source and have lower emissions and higher energy efficiency compared to traditional gasoline vehicles.

[0004] However, as new energy vehicles become more widespread, charging issues have become increasingly prominent. For example, when the output voltage of a charging station is lower than the charging voltage of the battery, new energy vehicles using this technology cannot utilize that output voltage to charge the battery, thus failing to meet users' charging needs and severely impacting the user experience. Summary of the Invention

[0005] In view of this, in order to at least solve the technical problem in the related technology that the output voltage of the charging pile is less than the battery charging voltage and thus cannot meet the battery charging requirements, the purpose of this application is to provide a battery charging and discharging device and a new energy vehicle.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:

[0007] A first aspect of this application provides a battery charging and discharging device, comprising: a charging interface for connecting to an external DC power supply, including a positive terminal and a negative terminal; an electric drive assembly including a motor, a first bridge arm, and a second bridge arm; each phase line of the motor being connected to a first end of the first bridge arm and the first end of the second bridge arm, and the neutral line of the motor being connected to either the positive terminal or the negative terminal; a second end of the first bridge arm being connected to the positive terminal, and / or the second end of the second bridge arm being connected to the negative terminal; and a battery pack interface for connecting the first terminal of the positive terminal of a power battery pack to the neutral terminal of the motor. A line connection is provided, which connects the second input terminal of the negative terminal of the power battery pack to the second end of the second bridge arm; when the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, the first bridge arm and the second bridge arm are alternately switched on and off, or the second bridge arm is alternately switched on and off, to alternately switch the inductor energy storage circuit and the battery charging circuit; the inductor energy storage circuit is used to charge the inductor in the motor, and the inductor energy storage circuit includes the external DC power supply and the inductor; the battery charging circuit is used to charge the power battery pack, and the battery charging circuit includes the inductor and the power battery pack.

[0008] In an optional embodiment, when the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, the inductor energy storage circuit charges the inductor for a first duration during each conduction process; when the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm alternately turn on and off, or the second bridge arm alternately turns on and off, to alternately switch the inductor energy storage circuit and the battery charging circuit, and the inductor energy storage circuit charges the inductor for a second duration during each conduction process; wherein, the first duration is longer than the second duration.

[0009] In an optional embodiment, the neutral line of the motor is connected to the negative terminal; the second end of the first bridge arm is connected to the positive terminal; in the inductor energy storage circuit, the first bridge arm is in a conducting state and the second bridge arm is in a disconnected state; in the battery charging circuit, the first bridge arm is in a disconnected state and the second bridge arm is in a conducting state.

[0010] In an optional embodiment, the neutral line of the motor is connected to the positive terminal; the second end of the second bridge arm is connected to the negative terminal; in the inductive energy storage circuit, the first bridge arm is in the open state, the switch in the second bridge arm is in the on state, and the diode in the second bridge arm is in the off state; in the battery charging circuit, the first bridge arm is in the open state, the switch in the second bridge arm is in the open state, and the diode in the second bridge arm is in the on state.

[0011] In an optional embodiment, the first access terminal of the battery pack interface is also connected to the second end of the first bridge arm; when the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first bridge arm is in the open state and the second bridge arm is in the closed state, and the external DC power supply, the power battery pack and the inductor form a direct charging circuit.

[0012] In an optional embodiment, the second end of the first bridge arm is connected to the positive terminal, and the second end of the second bridge arm is connected to the negative terminal. The device further includes: a first relay connected in series in the main circuit where the neutral line of the motor is located; and a second relay connected in series between the second end of the second bridge arm and the negative terminal. When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay, the first bridge arm, and the second bridge arm are all in an open state, the second relay is in a closed state, and the external DC power supply and the power battery pack form a direct charging circuit.

[0013] In an optional embodiment, the battery charging and discharging device further includes a first voltage-stabilizing capacitor; the first voltage-stabilizing capacitor is connected in parallel with the battery pack interface.

[0014] In an optional implementation, at least one of the two ends of the first voltage-stabilizing capacitor is connected to the battery pack interface via a relay.

[0015] In an optional embodiment, a relay is connected in series between the first access terminal of the battery pack interface and the second end of the first bridge arm; and / or a relay is connected in series between the second access terminal of the battery pack interface and the second end of the second bridge arm; and / or a relay is connected in series between the second end of the first bridge arm and the positive access terminal; and / or a relay is connected in series between the second end of the second bridge arm and the negative access terminal; and / or a main fuse is connected in series between the first access terminal of the battery pack interface and the second end of the first bridge arm; and / or a shunt is connected in series between the second access terminal of the battery pack interface and the second end of the second bridge arm.

[0016] In an optional embodiment, the second end of the first bridge arm is connected to the positive terminal, and the second end of the second bridge arm is connected to the negative terminal. The battery charging and discharging device further includes: a first relay connected in series in the main circuit where the neutral line of the motor is located; a third relay, one end of which is connected between the multiple battery packs included in the power battery pack, and the other end of which is connected between the neutral line of the motor and the first relay; when the temperature of the power battery pack is lower than a set temperature threshold, the first relay is in an open state, the third relay is in a closed state, and the first bridge arm and the second bridge arm are alternately switched on and off to alternately switch the battery discharge circuit and the battery pre-charge circuit, thereby raising the temperature of the power battery pack; in the battery discharge circuit, the first bridge arm is in a closed state, the second bridge arm is in an open state, the first battery pack in the power battery pack is short-circuited by the third relay, and the second battery pack in the power battery pack that is not short-circuited discharges to the inductor; in the battery pre-charge circuit, the first bridge arm is in an open state, the second bridge arm is in a closed state, and the first battery pack is charged by the inductor.

[0017] In an optional implementation, the charging interface is also used to connect an external load.

[0018] In an optional embodiment, the battery charging and discharging device further includes: an electrical device component, including an electrical device interface and a power interface; the electrical device interface is used to connect to an electrical device; the power interface is connected to the charging interface or the battery pack interface, and is used to introduce external DC power through the charging interface, or to introduce power provided by the power battery pack through the battery pack interface.

[0019] In an optional embodiment, the electric drive assembly further includes a second voltage-regulating capacitor, the two ends of which are respectively connected to the second end of the first bridge arm and the second end of the second bridge arm.

[0020] In an optional embodiment, the second end of the first bridge arm is connected to the positive terminal; the battery charging and discharging device further includes: a fourth relay connected in series between the first terminal of the battery pack interface and the second end of the first bridge arm; a pre-charging circuit including a resistor and a fifth relay connected in series; the pre-charging circuit is connected in parallel with the fourth relay; when the difference between the terminal voltage of the second voltage regulator and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference value, the fourth relay is in an open state and the fifth relay is in a closed state; when the difference between the terminal voltage of the second voltage regulator and the terminal voltage of the power battery pack is less than the set voltage difference value, the fourth relay is in a closed state and the fifth relay is in an open state.

[0021] A second aspect of this application provides a new energy vehicle, including: a power battery pack; and a battery charging and discharging device; the battery charging and discharging device includes the battery charging and discharging device provided in any of the first aspects above.

[0022] The battery charging and discharging device and new energy vehicle provided in any of the above embodiments of this application, by cooperating with the charging interface, electric drive assembly, and battery pack interface, configure an inductor energy storage circuit and a battery charging circuit for the battery charging and discharging device. This allows the inductor in the electric drive assembly to be charged first through the inductor energy storage circuit when the output voltage of the external DC power supply connected to the charging interface is lower than the charging voltage of the power battery pack connected to the battery pack interface. This allows the inductor to continuously store energy until its terminal voltage exceeds the charging voltage of the power battery pack. Then, the battery charging circuit allows the inductor to charge the power battery pack. Therefore, in the process of charging the inductor using the inductor energy storage circuit, this application can utilize an external DC power supply to charge the inductor, thereby raising the inductor's terminal voltage to a level higher than the charging voltage of the power battery pack. This allows an external DC power supply with an output voltage lower than the charging voltage of the power battery pack to meet the battery's charging requirements.

[0023] Furthermore, even though the output voltage and output current of the external DC power supply have various parameters, as can be seen from the above, when its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided in this application embodiment can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided in this application embodiment can also be compatible with charging piles with different parameters in this situation.

[0024] Furthermore, since the electric drive assembly can reuse the electric drive assembly that comes with new energy vehicles, it can also reduce the manufacturing cost of battery charging and discharging devices and new energy vehicles, and improve the space utilization rate inside the vehicle.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0026] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0027] Figure 1a shows a structural block diagram of a battery charging and discharging device provided in an embodiment of this application;

[0028] Figure 1b shows a circuit diagram of a battery charging and discharging device provided in an embodiment of this application;

[0029] Figure 2a shows a structural block diagram of another battery charging and discharging device provided in an embodiment of this application;

[0030] Figure 2b shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0031] Figure 3 shows a circuit diagram of a battery charging and discharging device with direct charging function provided in an embodiment of this application;

[0032] Figure 4a shows a circuit diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor provided in an embodiment of this application;

[0033] Figure 4b shows a circuit diagram of another battery charging and discharging device with a first voltage-regulating capacitor provided in an embodiment of this application;

[0034] Figure 5a shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0035] Figure 5b shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0036] Figure 5c shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0037] Figure 5d shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0038] Figure 5e shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0039] Figure 5f shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0040] Figure 5g shows a circuit diagram of another battery charging and discharging device provided in an embodiment of this application;

[0041] Figure 6 shows a circuit diagram of a battery charging and discharging device with battery preheating function provided in an embodiment of this application.

[0042] Figure 7a shows a circuit diagram of a battery charging and discharging device connected to an internal load according to an embodiment of this application;

[0043] Figure 7b shows a circuit diagram of another battery charging and discharging device with access to an internal load provided in an embodiment of this application.

[0044] Icons: 100 - Charging interface, 200 - Electric drive assembly, 210 - First bridge arm, 220 - Second bridge arm, M - Motor, 300 - Battery pack interface, K1 - First relay, K2 - Second relay, K3 - Third relay, K4 - Fourth relay, K5 - Fifth relay, Ka - Relay, Kb - Relay, Kc - Relay, Kd - Relay, Ke - Relay, R - Resistor, C1 - First voltage regulator capacitor, C2 - Second voltage regulator capacitor, A - Main fuse, B - Shunt. Detailed Implementation

[0045] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0046] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] In the description of this application, it should be noted that when terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are used, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the corresponding drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] Furthermore, terms such as "horizontal" and "vertical" do not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" may simply mean that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0050] In the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; and they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0051] To address the technical problem in related technologies where the output voltage of a charging pile is lower than the battery charging voltage, thus failing to meet battery charging requirements, this application provides a battery charging and discharging device. By utilizing a charging interface, an electric drive assembly, and a battery pack interface, the device is equipped with an inductor energy storage circuit and a battery charging circuit. This allows the device to first charge the inductor in the electric drive assembly through the inductor energy storage circuit when the output voltage of the external DC power supply connected to the charging interface is lower than the charging voltage of the power battery pack connected to the battery pack interface. This allows the inductor to continuously store energy until its terminal voltage exceeds the charging voltage of the power battery pack. Then, the battery charging circuit allows the inductor to charge the power battery pack. Therefore, this application allows the use of an external DC power supply to charge the inductor during the inductor energy storage circuit charging process, thereby raising the inductor's terminal voltage to a level higher than the charging voltage of the power battery pack. This enables an external DC power supply with an output voltage lower than the charging voltage of the power battery pack to meet the battery charging requirements.

[0052] Furthermore, even though the output voltage and output current of the external DC power supply have various parameters, as can be seen from the above, when its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided in this application embodiment can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided in this application embodiment can also be compatible with charging piles with different parameters in this situation.

[0053] Furthermore, since the electric drive assembly can reuse the electric drive assembly that comes with new energy vehicles, it can also reduce the manufacturing cost of battery charging and discharging devices and new energy vehicles, and improve the space utilization rate inside the vehicle.

[0054] The battery charging and discharging device provided in the embodiments of this application will be described below with reference to FIG1a. Please refer to FIG1a, which is a structural block diagram of a battery charging and discharging device provided in the embodiments of this application. The battery charging and discharging device includes a charging interface 100, an electric drive assembly 200, and a battery pack interface 300.

[0055] The charging interface 100 is used to connect to an external DC power source, including a positive input terminal and a negative input terminal.

[0056] The electric drive assembly 200 includes a motor M, a first bridge arm 210, and a second bridge arm 220; each phase line of the motor M is connected to the first end of the first bridge arm 210 and the first end of the second bridge arm 220, respectively; the neutral line of the motor M is connected to either the positive or negative terminal; the second end of the first bridge arm 210 is connected to the positive terminal, and / or the second end of the second bridge arm 220 is connected to the negative terminal.

[0057] The battery pack interface 300 has a first access terminal for connecting to the positive terminal of the power battery pack and connected to the neutral line of the motor M, and a second access terminal for connecting to the negative terminal of the power battery pack and connected to the second end of the second bridge arm 220.

[0058] When the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, the first bridge arm 210 and the second bridge arm 220 are switched on and off alternately, or the second bridge arm 220 is switched on and off alternately, so as to alternately switch the inductor energy storage circuit and the battery charging circuit.

[0059] The inductor energy storage circuit is used to charge the inductor in motor M. The inductor energy storage circuit includes an external DC power supply and an inductor.

[0060] The battery charging circuit is used to charge the power battery pack, and the battery charging circuit includes an inductor and the power battery pack.

[0061] The battery charging and discharging device provided in this application embodiment can be sold as a standalone product or as part of a carrier that uses batteries as a power source. The carrier may include, but is not limited to, new energy vehicles, new energy aircraft, or other new energy transportation tools.

[0062] Taking a new energy vehicle as an example, the battery charging and discharging device provided in this application embodiment reuses the electric drive assembly 200 of the new energy vehicle. It can charge the power battery pack with a low-voltage DC power supply (a DC power supply with an output voltage lower than the charging voltage of the power battery pack) without setting up other components. This can reduce the manufacturing cost of the charging and discharging device for the whole vehicle and improve the space utilization rate inside the vehicle.

[0063] The following uses the battery charging and discharging device provided in this application embodiment as an example of its application in a new energy vehicle to illustrate the working principle of the battery charging and discharging device provided in this application embodiment:

[0064] When applying a charging and discharging device to new energy vehicles, the power battery pack can be connected to the battery pack interface 300. Thus, in scenarios where the power battery pack of a new energy vehicle needs charging, an external DC power source can be connected to the charging interface 100 of the battery charging and discharging device, for example, by connecting the charging interface 100 to a charging pile. Subsequently, the controller in the new energy vehicle can use relevant technologies to determine the output voltage of the external DC power source currently connected to the charging interface 100 and compare the output voltage with the charging voltage of the power battery pack.

[0065] After comparison, if it is determined that the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, then to meet the charging requirements of the power battery pack, the relevant components in the circuit structure of the battery charging and discharging device may include multiple wiring methods. In this embodiment, two wiring methods are provided, which will be described below with reference to Figures 1a, 1b, 2a, and 2b. Figure 1b is a circuit diagram of a battery charging and discharging device provided in this embodiment; Figure 2a is a structural block diagram of another battery charging and discharging device provided in this embodiment; and Figure 2b is a circuit diagram of another battery charging and discharging device provided in this embodiment.

[0066] The first method involves connecting the neutral wire of motor M to the negative terminal and connecting the second end of the first bridge arm 210 to the positive terminal.

[0067] In this case, there is no connection between the second end of the second bridge arm 220 and the negative terminal, as shown in Figure 1a. Alternatively, a relay can be installed between the second end of the second bridge arm 220 and the negative terminal, but this relay is in an open state to ensure the normal operation of the inductor energy storage circuit and the battery charging circuit. Simultaneously, the relay can also achieve a certain degree of circuit isolation. Based on this, the controller controls the first bridge arm 210 and the second bridge arm 220 to alternately switch between the inductor energy storage circuit and the battery charging circuit. That is, in the inductor energy storage circuit, the first bridge arm 210 is in a conducting state, and the second bridge arm 220 is in an open state; in the battery charging circuit, the first bridge arm 210 is in an open state, and the second bridge arm 220 is in a conducting state. The second bridge arm 220 being in a conducting state can mean that the conduction direction of the diode in the second bridge arm 220 is consistent with the current direction in the battery charging circuit. Based on this, the switching transistor in the second bridge arm 220 can be further controlled to conduct, or the switching transistor in the second bridge arm 220 can be left uncontrolled.

[0068] In some examples, the controller can control the first bridge arm 210 and the second bridge arm 220 to alternately switch on and off at a set frequency, where the set frequency can be obtained from experience or experimentation, for example, it can be set to 100,000 times / second.

[0069] The corresponding switching process between the inductor energy storage circuit and the battery charging circuit is as follows:

[0070] The controller first turns on the first bridge arm 210 and turns off the second bridge arm 220. In this case, as shown in Figure 1b, the current direction in the inductor energy storage circuit is: positive terminal of external DC power supply → first bridge arm 210 → inductor → negative terminal of external DC power supply → positive terminal of external DC power supply. During this process, the external DC power supply continuously charges the inductor. After a first duration, it indicates that the inductor's terminal voltage has exceeded the charging voltage of the power battery pack, thus achieving a boost effect. The first duration can be determined by the controller based on the charging voltage of the power battery pack and the output voltage of the external DC power supply; details can be found in relevant technologies and will not be elaborated here.

[0071] When the alternating on / off control cycle is reached, it can be understood that when the conduction time of the first bridge arm 210 reaches the first duration, the controller controls the first bridge arm 210 to disconnect and the second bridge arm 220 to conduct. In this case, please refer to Figure 1b. The current direction of the battery charging circuit is: inductor → power battery pack (battery pack 1 → battery pack 2) → second bridge arm 220 → inductor. During this process, since the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, the inductor can charge the power battery pack. It can be seen that even if the external DC power supply is a low-voltage DC power supply, it can still meet the charging requirements of the power battery pack.

[0072] Therefore, after the battery charging and discharging device is connected to the aforementioned external DC power supply, this application can achieve low-voltage charging of the inductor by the external DC power supply through the alternating switching of the first bridge arm 210 and the second bridge arm 220, and then intermittent boost charging of the power battery pack through the inductor until the power battery pack is fully charged or the external DC power supply is disconnected.

[0073] The second method: the neutral line of motor M is connected to the positive terminal, and the second end of the second bridge arm 220 is connected to the negative terminal.

[0074] In this case, there is no connection between the second end of the first bridge arm 210 and the positive terminal, as shown in Figure 2a. Alternatively, a relay can be installed between the second end of the first bridge arm 210 and the positive terminal, but the relay is in an open state to ensure the normal operation of the inductor energy storage circuit and the battery charging circuit. The relay also provides some circuit isolation. The controller does not need to focus on the first bridge arm 210, but mainly on the control of the second bridge arm 220. That is, in both the inductor energy storage circuit and the battery charging circuit, the first bridge arm 210 is in an open state, while the second bridge arm 220 is in an alternating on / off state—in the inductor energy storage circuit, the first bridge arm 210 is in an open state, the switch in the second bridge arm 220 is in a conducting state, and the diode in the second bridge arm 220 is in a cutoff state; in the battery charging circuit, the first bridge arm 210 is in an open state, the switch in the second bridge arm 220 is in an open state, and the diode in the second bridge arm 220 is in a conducting state.

[0075] In some examples, the controller can also control the alternating switching of the switching transistors in the second bridge arm 220 at a set frequency.

[0076] The corresponding switching process between the inductor energy storage circuit and the battery charging circuit is as follows:

[0077] The controller controls or keeps the first bridge arm 210 disconnected and the switching transistor of the second bridge arm 220 on. In this case, referring to Figure 2b, the current direction of the inductor energy storage circuit is: positive terminal of external DC power supply → inductor → switching transistor of the second bridge arm 220 → negative terminal of external DC power supply → positive terminal of external DC power supply. During this process, the external DC power supply continuously charges the inductor. After the first duration is reached, it indicates that the terminal voltage of the inductor has exceeded the charging voltage of the power battery pack, thereby achieving the boost effect. The determination of the first duration can be found in the above description and will not be repeated here.

[0078] When the alternating on / off control cycle is reached, it can be understood that when the switching transistor of the second bridge arm 220 has been on for the first duration, the controller continues to keep the first bridge arm 210 off and controls the switching transistor of the second bridge arm 220 to be off. In this case, please refer to Figure 2b. The current direction of the battery charging circuit is: inductor → power battery pack (battery pack 1 → battery pack 2) → diode of the second bridge arm 220 → inductor. During this process, since the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, the inductor can charge the power battery pack. It can be seen that even if the external DC power supply is a low-voltage DC power supply, it can meet the charging requirements of the power battery pack.

[0079] Therefore, after the battery charging and discharging device is connected to the external DC power supply, this application can realize the intermittent low-voltage charging of the inductor by the external DC power supply through the alternating switching of the switching transistor in the second bridge arm 220, and then the intermittent boost charging of the power battery pack through the inductor until the power battery pack is fully charged or the external DC power supply is disconnected.

[0080] Furthermore, when the first bridge arm 210 and / or the second bridge arm 220 includes multiple switching transistors, if the first bridge arm 210 or the second bridge arm 220 is turned on, the number of switching transistors turned on in the first bridge arm 210 or the second bridge arm 220 can be adjusted according to the magnitude of the current in the circuit. For example, when the current in the circuit is large, the number of switching transistors turned on can be increased to achieve current shunting and prevent the switching transistors from overheating or even being damaged due to excessive current passing through them. When the current in the circuit is small, the number of switching transistors turned on can be reduced.

[0081] In the circuit schematics shown in Figures 1b and 2b above, all components other than the charging interface 100, the electric drive assembly 200, and the power battery pack 300 can be omitted, because the arrangement of these other components is designed to achieve other circuit functions and belongs to other variations. Please refer to the relevant records below for details.

[0082] Furthermore, for the convenience of the following description, in the embodiments of this application, the above charging mode is referred to as boost charging mode, and the corresponding scheme is boost charging scheme.

[0083] Since the external DC power supply may be a high-voltage, low-current type, where the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, in order to improve the charging speed of the power battery pack, the battery charging and discharging device in any of the above embodiments can also be used to charge the power battery pack. The difference from the above boost charging mode is that in the inductor energy storage circuit, the charging time of the inductor is shorter than the inductor charging time in the above boost charging mode. The corresponding buck-boost charging mode is as follows:

[0084] When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the first bridge arm 210 and the second bridge arm 220 are alternately switched on and off, or the second bridge arm 220 is alternately switched on and off, to alternately switch the inductor energy storage circuit and the battery charging circuit. In addition, the inductor energy storage circuit charges the inductor for a second duration during each conduction process.

[0085] The second duration is longer than the first duration. As mentioned above, the first duration refers to the duration during which the inductor energy storage circuit charges the inductor each time it is turned on, when the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack.

[0086] The switching principle between the inductor energy storage circuit and the battery charging circuit can be found in the relevant records above, and will not be repeated here.

[0087] When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the charging process using the inductor energy storage circuit can step down the voltage of the external DC power supply—distributing the output voltage of the external DC power supply to the inductor, thereby reducing the output voltage of the external DC power supply to the charging voltage required by the power battery pack, while simultaneously maximizing the current of the external DC power supply—that is, reaching the maximum output current of the external DC power supply. Therefore, during the charging process of the power battery pack using the battery charging circuit, since the charging power of the external DC power supply remains constant, the overall charging power of the battery charging circuit also remains constant. Since power equals the product of voltage and current, a decrease in charging voltage can increase the charging current, thereby increasing the charging current of the power battery pack and improving the charging speed. It is evident that the battery charging and discharging device provided in this application not only has the function of boost charging but also the function of buck charging with increased current, possessing stronger compatibility and practicality with charging piles.

[0088] In addition to the two types of external DC power supplies mentioned above, there are also external DC power supplies with an output voltage higher than the charging voltage of the power battery pack and an output current greater than or equal to the maximum charging current of the power battery pack. In this case, to better improve the charging speed of the power battery pack, an external DC power supply can be used to directly charge the power battery pack. This also helps to further improve the compatibility and practicality of the battery charging and discharging device provided in this application embodiment. Based on this, in some embodiments, the battery charging and discharging device provided in this application embodiment can also have a direct charging mode. The direct charging scheme provided in this application embodiment includes:

[0089] The first direct charging solution:

[0090] In the first direct charging scheme, it can be achieved by adding one connection to the boost charging scheme without adding other components. The circuit is simple and low in cost.

[0091] Please refer to Figure 1a or Figure 1b. The first access terminal of the battery pack interface 300 is also connected to the second end of the first bridge arm 210. That is, an additional connection is added to connect the first access terminal and the second end of the first bridge arm 210.

[0092] Based on this, when the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first bridge arm 210 is in the open state, the second bridge arm 220 is in the closed state, and the external DC power supply, the power battery pack and the inductor form a direct charging circuit.

[0093] When the battery charging and discharging device provided in this application is connected to an external DC power supply, the controller can also compare the output voltage and output current of the external DC power supply with the charging voltage and maximum charging current of the power battery pack, respectively. When determining to execute the direct charging mode based on the comparison result, the controller controls or keeps the first bridge arm 210 disconnected and the second bridge arm 220 connected, thereby connecting the direct charging circuit. Please refer to Figure 1b. The current direction of the direct charging circuit is: positive terminal of external DC power supply → power battery pack (battery pack 1 → battery pack 2) → second bridge arm 220 → inductor → negative terminal of external DC power supply → positive terminal of external DC power supply.

[0094] The second direct charging solution:

[0095] As can be seen from the first scheme above, the direct charging circuit includes a part of the electric drive assembly 200. In the second direct charging scheme, a direct charging circuit that does not include the electric drive assembly 200 can be provided based on any of the above embodiments, which can save charging energy and reduce heat loss to a certain extent.

[0096] Please refer to Figure 3, which is a circuit diagram of a battery charging and discharging device with direct charging function provided in an embodiment of this application. The second end of the first bridge arm 210 is connected to the positive terminal, and the second end of the second bridge arm 220 is connected to the negative terminal. Accordingly, the battery charging and discharging device provided in this embodiment may further include:

[0097] The first relay K1 is connected in series in the main circuit where the neutral line of motor M is located;

[0098] The second relay K2 is connected in series between the second end of the second bridge arm 220 and the negative terminal;

[0099] When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay K1, the first bridge arm 210 and the second bridge arm 220 are all in the open state, and the second relay K2 is in the closed state, forming a direct charging circuit between the external DC power supply and the power battery pack.

[0100] When the battery charging and discharging device provided in this application is connected to an external DC power supply, the controller can also compare the output voltage and output current of the external DC power supply with the charging voltage and maximum charging current of the power battery pack, respectively. When determining to execute the direct charging mode based on the comparison result, the controller controls or keeps the first relay K1, the first bridge arm 210 and the second bridge arm 220 disconnected, and controls the second relay K2 to conduct, thereby connecting the direct charging circuit. Please continue to refer to Figure 3. The current direction of the direct charging circuit is: positive terminal of external DC power supply → power battery pack (battery pack 1 → battery pack 2) → second relay K2 → negative terminal of external DC power supply → positive terminal of external DC power supply.

[0101] Based on the embodiment shown in Figure 3, when the battery charging and discharging device operates in boost charging mode or buck-boost charging mode, the first relay K1 is in the on state and the second relay K2 is in the off state to ensure the normal operation of boost charging mode or buck-boost charging mode. The control principles of the first bridge arm 210 and the second bridge arm 220 can be found in the relevant descriptions above, and will not be repeated here.

[0102] It is evident that the configuration of the first relay K1 and the second relay K2 ensures that the boost charging mode, buck charging mode, and direct charging mode do not interfere with each other, enabling the battery charging and discharging device to be compatible with charging piles with more different parameters, thus possessing stronger compatibility and practicality.

[0103] Therefore, when the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, any of the above direct charging schemes can enable the external DC power supply to directly charge the power battery pack, which is beneficial to improving the charging speed.

[0104] In boost charging mode or buck-boost charging mode, the battery charging circuit may have a large ripple current, which can affect the battery's lifespan and cause the battery to heat up. After the battery heats up, it will affect the battery performance. Therefore, in order to avoid the adverse effects of ripple current on battery lifespan and battery performance, in some embodiments, please refer to Figure 4a. Figure 4a is a circuit structure schematic diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor C1 provided by an embodiment of this application. The battery charging and discharging device provided by this embodiment of the application may also include a first voltage-stabilizing capacitor C1, which is connected in parallel with the battery pack interface 300.

[0105] As shown in Figure 4a, the first voltage-stabilizing capacitor C1 is connected in parallel across the two ends of the battery pack interface 300. It is evident that the first voltage-stabilizing capacitor C1 and the battery pack interface 300 are interconnected. This presents two risks: firstly, at the moment the power battery pack is powered on, the first voltage-stabilizing capacitor C1 may spark, potentially damaging the circuit; secondly, due to the presence of the power battery pack, the first voltage-stabilizing capacitor C1 will be charged, posing a risk of electric shock to assemblers or other components during assembly due to the discharge of the first voltage-stabilizing capacitor C1.

[0106] Therefore, to avoid arcing in the first voltage-stabilizing capacitor C1 and reduce the assembly risk of the first voltage-stabilizing capacitor C1, in some embodiments, please refer to Figure 4b. Figure 4b is a circuit structure schematic diagram of another battery charging and discharging device with a first voltage-stabilizing capacitor C1 provided by an embodiment of this application. The battery charging and discharging device provided by this embodiment of the application can also be configured with corresponding safety protection devices for the first voltage-stabilizing capacitor C1, that is, at least one of the two ends of the first voltage-stabilizing capacitor C1 is connected to the battery pack interface 300 through a relay. In Figure 4b, it can be seen that the two ends of the first voltage-stabilizing capacitor C1 are connected to the battery pack interface 300 through the fourth relay K4 and the relay Kc, respectively.

[0107] Therefore, when the battery charging and discharging device is not in operation, the relay between the first voltage regulator C1 and the battery pack interface 300 can be disconnected, so that the first voltage regulator C1 is not energized, which can reduce assembly risks and prevent arcing.

[0108] Based on the previous embodiment, in some embodiments, to further protect the safety of the battery and circuit, please continue to refer to FIG4b. The battery charging and discharging device provided in this application embodiment may further include a pre-charging circuit, which includes a resistor R and a fifth relay K5 connected in series; the pre-charging circuit is connected in parallel with the fourth relay K4.

[0109] When the difference between the terminal voltage of the first voltage regulator capacitor C1 and the terminal voltage of the power battery pack is greater than or equal to the set voltage difference, the fourth relay K4 is in the open state and the fifth relay K5 is in the closed state.

[0110] When the difference between the terminal voltage of the first voltage regulator capacitor C1 and the terminal voltage of the power battery pack is less than the set voltage difference value, the fourth relay K4 is in the conducting state and the fifth relay K5 is in the disconnected state.

[0111] During driving operation, specifically when the power battery pack supplies power to the electric drive assembly 200, a large instantaneous voltage is generated in the circuit at the moment the connection between the power battery pack and the electric drive assembly 200 is established. This voltage surge impacts the motor M of the electric drive assembly 200, affecting its performance or lifespan, and also impacting the normal operation of the entire circuit. Therefore, the pre-charging circuit described above ensures that the terminal voltage of the electric drive system assembly is stabilized before the power battery pack supplies power to the electric drive system assembly. This effectively avoids the impact of instantaneous voltage on the electric drive assembly 200, thus improving circuit safety.

[0112] Based on any embodiment of the battery charging and discharging device of this application including the first voltage stabilizing capacitor C1, in some embodiments, in order to achieve further isolation between the electric drive assembly 200 and the power battery pack, please continue to refer to Figures 4a and 4b, the battery charging and discharging device provided in the embodiments of this application may also include a relay Kd, which is connected in series between the end of the first voltage stabilizing capacitor C1 connected to the first access terminal and the first end of the first bridge arm 210.

[0113] Therefore, the power battery pack and the electric drive assembly 200 can be further isolated by the relay Kd. Based on this, when the difference between the terminal voltage of the first voltage regulator C1 and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference value, the relay Kd can be disconnected to achieve the first layer of isolation; correspondingly, when the difference between the terminal voltage of the first voltage regulator C1 and the terminal voltage of the power battery pack is less than the set voltage difference value, the relay Kd can be turned on. At the same time, it can also isolate the external DC power supply and the electric drive assembly 200, effectively avoiding the impact of the external DC power supply on the electric drive assembly 200, achieving the second layer of isolation. It can be seen that the relay Kd has a dual isolation function.

[0114] Based on any of the above embodiments, to avoid affecting motor drive due to the charging interface 100 being energized during driving, in some embodiments, please refer to FIG5a. FIG5a is a circuit diagram of another battery charging and discharging device provided in this application embodiment. The battery charging and discharging device provided in this application embodiment may further include a relay Ke, which is connected in series in the branch between the neutral line of the motor M and the charging interface 100. It can be understood that when the neutral line of the motor M is connected to the positive terminal, the relay Ke is connected in series in the branch segment between the neutral line and the positive terminal of the motor M; when the neutral line of the motor M is connected to the negative terminal, the relay Ke is connected in series in the branch segment between the neutral line and the negative terminal of the motor M, as shown in FIG5a.

[0115] Therefore, under driving conditions, the controller can control the relay Ke to disconnect so that the charging interface 100 is not energized, thereby avoiding the influence of external DC power supply on the motor drive and improving the driving reliability of motor M.

[0116] In addition, embodiments of this application also provide various variations of the combination of the control relay and the first voltage-stabilizing capacitor C1, as shown in Figures 5b to 5g. Figures 5b to 5e are circuit diagrams of another battery charging and discharging device provided by embodiments of this application. Figures 5b to 5e show not only the combination of the first voltage-stabilizing capacitor C1 and the relay Ke, but also variations in the position of the relay in the circuit. Figures 5f and 5g show not only the combination of the first voltage-stabilizing capacitor C1 and the relay Ke, but also a scheme where the position of the first relay K1 can be adaptively adjusted to save on the number of relays.

[0117] In addition to the examples shown in Figures 5a to 5g, there may be other variations in the location of the node connecting the neutral line of motor M to the first access terminal. For example, it may be located between the first access terminal and the fourth relay K4.

[0118] The combination of relay Ke and the first voltage-stabilizing capacitor C1 can not only avoid the influence of external DC power supply on the motor M drive, but also avoid the impact of instantaneous voltage of the power battery pack on the motor M. The combination of the two can better improve the safety and reliability of the motor drive.

[0119] While the above provides numerous examples of combinations of the first voltage-regulating capacitor C1 and the relay Ke, in other variations, the relay Ke and all other components except those required to implement the boost charging function can be removed. At least one of these removed components can be combined with the relay Ke and the required electronic components for the boost charging function. The same principle applies to the related examples throughout the text, as long as the technical solutions do not contain contradictions or logical errors.

[0120] In some embodiments, to improve circuit safety, please continue to refer to FIG3. The battery charging and discharging device provided in this application embodiment may further include at least one of the following circuit safety configuration schemes:

[0121] The first type: A relay is connected in series between the first access terminal of the battery pack interface 300 and the second terminal of the first bridge arm 210;

[0122] The second type: A relay Kc is connected in series between the second access terminal of the battery pack interface 300 and the second terminal of the second bridge arm 220;

[0123] The third type: A relay Ka is connected in series between the second end of the first bridge arm 210 and the positive terminal;

[0124] The fourth type: A relay is connected in series between the second end of the second bridge arm 220 and the negative terminal;

[0125] Fifth type: A main fuse A is connected in series between the first access terminal of the battery pack interface 300 and the second terminal of the first bridge arm 210;

[0126] The sixth type: A shunt B is connected in series between the second access terminal of the battery pack interface 300 and the second end of the second bridge arm 220.

[0127] Regarding the first circuit safety configuration scheme described above, based on the embodiment of the battery charging and discharging device provided in this application that includes a fourth relay K4, the configured relay can reuse the fourth relay K4, which helps to reduce circuit configuration costs. Of course, it is also possible not to reuse existing components, but to configure corresponding relays separately.

[0128] The relays configured in the first and second circuit safety configuration schemes described above can both isolate one end of the battery pack interface 300 and the electric drive assembly 200. They also have the inherent functions of the relays themselves, including but not limited to: automatically disconnecting the circuit when the current or voltage in the circuit exceeds the limit, thereby preventing equipment damage and effectively avoiding faults and losses caused by overload or short circuit.

[0129] Regarding the fourth safety configuration scheme described above, based on the embodiment of the battery charging and discharging device provided in this application that includes the second relay K2, the configured relay can reuse the second relay K2, which helps to reduce circuit configuration costs. Of course, it is also possible not to reuse the existing device, but to configure a corresponding relay separately.

[0130] The relays configured in the third and fourth circuit safety configuration schemes mentioned above can also achieve the technical effects of circuit isolation and circuit safety described above. In addition, since the relay between any bridge arm and the charging interface 100 is disconnected when not charging, the charging interface 100 will not be energized after being disconnected from the external DC power supply, thus ensuring the safety of the user when using the charging interface 100.

[0131] Because the battery temperature will drop to some extent in low-temperature environments, it will affect battery performance, such as the battery's power supply performance and charging speed. Therefore, in order to ensure the performance of the power battery pack in low-temperature environments, in some embodiments, the battery charging and discharging device provided in this application can also have a battery preheating function. Please refer to Figure 6. Figure 6 is a circuit diagram of a battery charging and discharging device with a battery preheating function provided in this application. The second end of the first bridge arm 210 is connected to the positive terminal, and the second end of the second bridge arm 220 is connected to the negative terminal.

[0132] Accordingly, the battery charging and discharging device provided in the embodiments of this application may further include:

[0133] The first relay K1 is connected in series in the main circuit where the neutral line of motor M is located;

[0134] The third relay K3 is connected at one end to the multiple battery packs contained in the power battery pack, and at the other end to the neutral line of the motor M and the first relay K1.

[0135] When the temperature of the power battery pack is lower than the set temperature threshold, the first relay K1 is in the open state and the third relay K3 is in the closed state. The first bridge arm 210 and the second bridge arm 220 are alternately switched on and off to alternately switch the battery discharge circuit and the battery pre-charge circuit, thereby raising the temperature of the power battery pack.

[0136] In the battery discharge circuit, the first bridge arm 210 is in the conducting state, the second bridge arm 220 is in the disconnected state, the first battery pack in the power battery pack is short-circuited by the third relay K3, and the second battery pack in the power battery pack that is not short-circuited discharges to the inductor.

[0137] In the battery pre-charge circuit, the first bridge arm 210 is in the open state, the second bridge arm 220 is in the closed state, and the first battery pack is charged by the inductor.

[0138] Although in the circuit shown in Figure 6, one end of the third relay K3 is connected to the midpoint of the voltage of the multiple battery packs included in the power battery pack—for example, assuming the power battery pack includes power battery pack 1 and power battery pack 2, and power battery pack 1 and power battery pack 2 have the same voltage—the midpoint of the voltage represents the midpoint of the line connecting power battery pack 1 and power battery pack 2. Connecting one end of the third relay K3 to the midpoint of the voltage ensures balanced charging and discharging of the battery during the subsequent battery preheating process. However, in other modified embodiments, one end of the third relay K3 can also be connected to a point in power battery pack 1 or a point in power battery pack 2, as long as battery preheating is achieved; it does not necessarily have to be connected to the midpoint of the voltage.

[0139] Therefore, the battery temperature can be detected by a temperature sensor configured at the power battery pack and fed back to the controller. The controller can then compare the battery temperature with a set temperature threshold based on relevant technical principles and control the on / off state of the corresponding relays based on the comparison result.

[0140] When the temperature of the power battery pack is lower than the set temperature threshold, the first relay K1 is in the open state and the third relay K3 is in the closed state. The first bridge arm 210 and the second bridge arm 220 are alternately switched on and off to alternately switch the battery discharge circuit and the battery pre-charge circuit, thereby raising the temperature of the power battery pack.

[0141] In the battery discharge circuit, the first bridge arm 210 is in the on state, the second bridge arm 220 is in the off state, the first battery pack (battery pack 2) in the power battery pack is short-circuited by the third relay K3, and the second battery pack (battery pack 1) in the power battery pack, which is not short-circuited, discharges to the inductor.

[0142] Taking Figure 6 as an example, the current flow of the battery discharge circuit is as follows: positive terminal of battery pack 1 → first bridge arm 210 → inductor of motor M → third relay K3 → negative terminal of battery pack 1 → positive terminal of battery pack 1, thus forming a battery discharge circuit, realizing that the battery pack 1 that is not short-circuited in the power battery pack discharges to the inductor, that is, the inductor is in a charging state.

[0143] In this situation, both the first relay K1 and the second bridge arm 220 are in the off state.

[0144] In the battery charging circuit, the first bridge arm 210 is in the open state, the second bridge arm 220 is in the closed state, and the first battery pack is charged by the inductor.

[0145] Taking Figure 6 as an example, the current flow of the battery pre-charge circuit is: inductor → third relay K3 → battery pack 2 → second bridge arm 220 → inductor, thus forming a battery charging circuit, enabling the inductor to charge the power battery pack 2.

[0146] In this situation, the first relay K1, the fourth relay K4, and the first bridge arm 210 are all in the open state.

[0147] Therefore, by first controlling the operation of the battery discharge circuit and then controlling the operation of the battery charging circuit, and alternately enabling the battery discharge circuit and the battery pre-charge circuit according to this strategy, the power battery pack can generate heat due to the alternating discharge and charge, thereby increasing the battery temperature of the power battery pack. When the battery temperature reaches the set temperature threshold, the battery preheating function can be stopped.

[0148] The alternation control frequency of the battery charging circuit and the battery pre-charge circuit can be found in the relevant records above, and will not be repeated here.

[0149] In some embodiments, to improve the practicality of the battery charging and discharging device, the battery charging and discharging device can also be used to charge an external load. That is, in addition to being used to connect to an external DC power source, the charging interface 100 can also be used to connect to an external load to supply power to the external load.

[0150] In some embodiments, to improve the practicality of the battery charging and discharging device, the battery charging and discharging device provided in this application embodiment can also charge electrical equipment. The electrical equipment can refer to the equipment contained within the battery charging and discharging device as a power source, and can also be called an internal load, which can be a high-voltage internal load. Based on this, the battery charging and discharging device provided in this application embodiment may further include:

[0151] Electrical equipment components, including electrical equipment interfaces and power interfaces;

[0152] The electrical equipment interface is used to connect electrical equipment;

[0153] The power interface is connected to the charging interface 100 or the battery pack interface 300, and is used to introduce external DC power through the charging interface 100 or to introduce power provided by the power battery pack through the battery pack interface 300.

[0154] For application scenarios where battery charging and discharging devices are connected to high-voltage loads, this application provides multiple implementation methods for connecting battery charging and discharging devices to high-voltage loads. Please refer to Figures 7a and 7b. Figures 7a and 7b are circuit diagrams of a battery charging and discharging device connected to an internal load provided by an embodiment of this application, showing two different variations. These two variations can be essentially divided into two categories:

[0155] Type 1: Internal loads draw power from an external DC power source, as shown in Figure 7a.

[0156] The second type: internal loads draw power from the power battery pack, as shown in Figure 7b.

[0157] As mentioned above, the internal load draws power from the power battery pack, which offers better stability and safety. This is because the withstand voltage of the internal load is generally matched with the voltage of the power battery pack during the production stage. However, there are various types of external DC power supplies, and their output voltage may not match the voltage of the internal load. Therefore, the voltage of the power battery pack will not be too high compared to the withstand voltage of the internal load, thus avoiding the internal load from burning out due to excessively high supply voltage.

[0158] In the driving condition, that is, when the power battery pack supplies power to the electric drive assembly 200, in order to avoid the generation of a large instantaneous voltage in the circuit at the moment the connection between the power battery pack and the electric drive assembly 200 is made, which would cause an impact on the motor M of the electric drive assembly 200 and thus affect the performance or life of the motor M, in some embodiments, please refer to Figure 1b, the electric drive assembly 200 may also include a second voltage stabilizing capacitor C2, the two ends of the second voltage stabilizing capacitor C2 being connected to the second end of the first bridge arm 210 and the second end of the second bridge arm 220, respectively.

[0159] Therefore, by using the second voltage regulator capacitor C2, the voltage can be regulated at the moment the circuit between the power battery pack and the electric drive assembly 200 is turned on. Then, after the voltage stabilizes, the electric drive assembly 200 is powered, which can avoid the impact of large instantaneous voltage on the motor M.

[0160] Based on the previous embodiment, in order to avoid large instantaneous voltage breakdown of the second voltage regulator C2 under driving conditions, in some embodiments, the battery charging and discharging device provided in this application further includes a pre-charging circuit, so that the second voltage regulator C2 is charged first under driving conditions, so that the terminal voltage of the second voltage regulator C2 and the voltage of the power battery pack are maintained within a set voltage difference, thereby effectively preventing instantaneous voltage breakdown of the second voltage regulator C2.

[0161] Based on this, the second end of the first bridge arm 210 is connected to the positive terminal.

[0162] Accordingly, the battery charging and discharging device provided in the embodiments of this application may further include:

[0163] The fourth relay K4 is connected in series between the first access terminal of the battery pack interface 300 and the second terminal of the first bridge arm 210;

[0164] The pre-charging circuit includes a resistor R connected in series with the fifth relay K5; the pre-charging circuit is connected in parallel with the fourth relay K4;

[0165] When the difference between the terminal voltage of the second voltage regulator capacitor C2 and the terminal voltage of the power battery pack is greater than or equal to the set voltage difference, the fourth relay K4 is in the open state and the fifth relay K5 is in the closed state.

[0166] When the difference between the terminal voltage of the second voltage regulator capacitor C2 and the terminal voltage of the power battery pack is less than the set voltage difference value, the fourth relay K4 is in the conducting state and the fifth relay K5 is in the disconnected state.

[0167] Taking Figure 1b as an example, in this example, the relay connected to the first access terminal is the fourth relay K4. Therefore, the pre-charging circuit is connected in parallel with the fourth relay K4. Thus, under driving conditions, relay Kc can be turned on first, and then the fifth relay K5 can be turned on. At this time, the current of the power battery pack flows through the resistor R, the fifth relay K5, the second voltage regulator capacitor C2, and the relay Kc in sequence, and then flows back to the negative terminal of the power battery pack. This achieves pre-charging of the second voltage regulator capacitor C2 and avoids instantaneous voltage breakdown of the second voltage regulator capacitor C2.

[0168] During the pre-charging process of the second voltage regulator capacitor C2, the terminal voltage of the second voltage regulator capacitor C2 and the terminal voltage of the power battery pack can be obtained through relevant technical principles. When the difference between the two terminal voltages is less than the set voltage difference value, the fifth relay K5 is controlled to open and the fourth relay K4 is controlled to open. This enables the power battery pack to supply power to the electric drive system assembly after the terminal voltage of the electric drive system assembly is regulated.

[0169] The voltage difference can be set based on experiments or experience, for example, 5V, but is not limited to this.

[0170] Corresponding to the embodiments of the battery charging and discharging device, this application also provides a new energy vehicle, including:

[0171] Vehicle body; and

[0172] A battery charging and discharging device is installed on the vehicle body; the battery charging and discharging device includes the battery charging and discharging device in any of the above embodiments.

[0173] The charging and discharging principles and driving principles of new energy vehicles mentioned above can be found in the description of the corresponding embodiments of the battery charging and discharging device provided in this application, and will not be repeated here.

[0174] It is worth noting that the technical features or technical solutions in any of the above embodiments of this application can be combined or combined with each other, as long as there is no contradiction in the combination or combination.

[0175] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A battery charging and discharging device, characterized in that, include: The charging interface is used to connect to an external DC power source, and includes a positive input terminal and a negative input terminal. An electric drive assembly includes a motor, a first bridge arm, and a second bridge arm; each phase line of the motor is connected to a first end of the first bridge arm and a first end of the second bridge arm, respectively, and the neutral line of the motor is connected to either the positive terminal or the negative terminal; the second end of the first bridge arm is connected to the positive terminal, and / or the second end of the second bridge arm is connected to the negative terminal. The battery pack interface has a first connection terminal for connecting to the positive terminal of the power battery pack and connecting to the neutral line of the motor, and a second connection terminal for connecting to the negative terminal of the power battery pack and connecting to the second end of the second bridge arm. When the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, the first bridge arm and the second bridge arm are switched on and off alternately, or the second bridge arm is switched on and off alternately, to alternately switch the inductor energy storage circuit and the battery charging circuit. The inductor energy storage circuit is used to charge the inductor in the motor, and the inductor energy storage circuit includes the external DC power supply and the inductor; The battery charging circuit is used to charge the power battery pack, and the battery charging circuit includes the inductor and the power battery pack.

2. The apparatus according to claim 1, characterized in that: When the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack, the inductor energy storage circuit charges the inductor for a first duration during each turn-on process. When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm are alternately switched on and off, or the second bridge arm is alternately switched on and off, to alternately switch the inductor energy storage circuit and the battery charging circuit. In addition, the inductor energy storage circuit charges the inductor for a second duration during each conduction process. Wherein, the first duration is longer than the second duration.

3. The apparatus according to claim 1 or 2, characterized in that, The neutral wire of the motor is connected to the negative terminal; the second end of the first bridge arm is connected to the positive terminal. In the inductive energy storage circuit, the first bridge arm is in the on state and the second bridge arm is in the off state; In the battery charging circuit, the first bridge arm is in the open state, and the second bridge arm is in the closed state.

4. The apparatus according to claim 1 or 2, characterized in that, The neutral wire of the motor is connected to the positive terminal; the second end of the second bridge arm is connected to the negative terminal. In the inductor energy storage circuit, the first bridge arm is in the open state, the switch in the second bridge arm is in the on state, and the diode in the second bridge arm is in the off state. In the battery charging circuit, the first bridge arm is in the open state, the switch in the second bridge arm is in the open state, and the diode in the second bridge arm is in the on state.

5. The apparatus according to claim 3, characterized in that, The first access end of the battery pack interface is also connected to the second end of the first bridge arm; When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first bridge arm is in the open state, the second bridge arm is in the closed state, and the external DC power supply, the power battery pack, and the inductor form a direct charging circuit.

6. The apparatus according to claim 1, characterized in that, The second end of the first bridge arm is connected to the positive terminal, and the second end of the second bridge arm is connected to the negative terminal. The device further includes: The first relay is connected in series in the main circuit where the neutral line of the motor is located; The second relay is connected in series between the second end of the second bridge arm and the negative terminal; When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay, the first bridge arm, and the second bridge arm are all in the open state, the second relay is in the closed state, and the external DC power supply and the power battery pack form a direct charging circuit.

7. The apparatus according to claim 1, characterized in that, It also includes a first voltage-regulating capacitor; the first voltage-regulating capacitor is connected in parallel with the battery pack interface.

8. The apparatus according to claim 7, characterized in that, At least one of the two ends of the first voltage-stabilizing capacitor is connected to the battery pack interface via a relay.

9. The apparatus according to claim 1, characterized in that: A relay is connected in series between the first access terminal of the battery pack interface and the second terminal of the first bridge arm; and / or A relay is connected in series between the second access terminal of the battery pack interface and the second end of the second bridge arm; and / or A relay is connected in series between the second end of the first bridge arm and the positive terminal; and / or A relay is connected in series between the second end of the second bridge arm and the negative terminal; and / or A main fuse is connected in series between the first access terminal of the battery pack interface and the second end of the first bridge arm; and / or A shunt is connected in series between the second access terminal of the battery pack interface and the second end of the second bridge arm.

10. The apparatus according to claim 1, characterized in that, The second end of the first bridge arm is connected to the positive terminal, and the second end of the second bridge arm is connected to the negative terminal. The device further includes: The first relay is connected in series in the main circuit where the neutral line of the motor is located; The third relay has one end connected between the multiple battery packs contained in the power battery pack, and the other end connected between the neutral line of the motor and the first relay. When the temperature of the power battery pack is lower than a set temperature threshold, the first relay is in the off state and the third relay is in the on state. The first bridge arm and the second bridge arm are alternately switched on and off to alternately switch the battery discharge circuit and the battery precharge circuit, thereby raising the temperature of the power battery pack. In the battery discharge circuit, the first bridge arm is in the on state, the second bridge arm is in the off state, the first battery pack in the power battery pack is short-circuited by the third relay, and the second battery pack in the power battery pack that is not short-circuited discharges to the inductor. In the battery precharge circuit, the first bridge arm is in the open state, the second bridge arm is in the closed state, and the first battery pack is charged by the inductor.

11. The apparatus according to claim 1, characterized in that, The charging interface is also used to connect to an external load.

12. The apparatus according to claim 1, characterized in that, Also includes: Electrical equipment components, including electrical equipment interfaces and power interfaces; The electrical equipment interface is used to connect electrical equipment; The power interface is connected to the charging interface or the battery pack interface, and is used to introduce external DC power through the charging interface or to introduce power provided by the power battery pack through the battery pack interface.

13. The apparatus according to claim 1, characterized in that, The electric drive assembly also includes a second voltage regulator capacitor, the two ends of which are respectively connected to the second end of the first bridge arm and the second end of the second bridge arm.

14. The apparatus according to claim 13, characterized in that, The second end of the first bridge arm is connected to the positive terminal. The device further includes: The fourth relay is connected in series between the first access terminal of the battery pack interface and the second end of the first bridge arm; The pre-charging circuit includes a resistor and a fifth relay connected in series; the pre-charging circuit is connected in parallel with the fourth relay. When the difference between the terminal voltage of the second voltage regulator and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference, the fourth relay is in the off state and the fifth relay is in the on state. When the difference between the terminal voltage of the second voltage stabilizing capacitor and the terminal voltage of the power battery pack is less than the set voltage difference value, the fourth relay is in the on state and the fifth relay is in the off state.

15. A new energy vehicle, characterized in that, include: Power battery pack; as well as A battery charging and discharging device; the battery charging and discharging device includes the battery charging and discharging device according to any one of claims 1 to 14.

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