Battery charging and discharging device and new energy automobile

Abstract

The embodiment of the utility model provides a battery charging and discharging device and a new energy automobile, and the battery charging and discharging device comprises a charging interface which is used for accessing an external DC power supply and comprises a positive electrode access end and a negative electrode access end; the electric drive assembly comprises a motor, a first bridge arm and a second bridge arm; each phase line of the motor is respectively connected with the first end of the first bridge arm and the first end of the second bridge arm, and a neutral line of the motor is connected with the positive pole access end or the negative pole access end; the second end of the first bridge arm is connected with the anode access end, and / or the second end of the second bridge arm is connected with the cathode access end; and the battery pack interface is used for connecting a first access end of a positive electrode of a power battery pack to be connected with a neutral line of the motor, and connecting a second access end of a negative electrode of the power battery pack to be connected with a second end of the second bridge arm. The battery charging requirement can still be met under the condition that the output voltage of the charging pile is smaller than the battery charging voltage.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicles, specifically to a battery charging and discharging device and a new energy vehicle. Background Technology

[0002] 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, both of which use electricity as their primary power source and have lower emissions and higher energy efficiency compared to traditional gasoline vehicles.

[0003] 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 related technologies cannot utilize that output voltage to charge the battery, thus failing to meet users' charging needs and severely impacting the user experience. Utility Model Content

[0004] 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 utility model is to provide a battery charging and discharging device and a new energy vehicle.

[0005] To achieve the above objectives, the technical solution adopted in this utility model embodiment is as follows:

[0006] A first aspect of this utility model provides a battery charging and discharging device, comprising:

[0007] The charging interface is used to connect to an external DC power source, and includes a positive input terminal and a negative input terminal.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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;

[0012] 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.

[0013] 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 turn-on process.

[0014] 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.

[0015] Wherein, the first duration is longer than the second duration.

[0016] In an optional embodiment, 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.

[0017] 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;

[0018] In the battery charging circuit, the first bridge arm is in the open state, and the second bridge arm is in the closed state.

[0019] In an optional embodiment, 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.

[0020] 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.

[0021] 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.

[0022] In an optional embodiment, the first access end of the battery pack interface is also connected to the second end of the first bridge arm;

[0023] 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.

[0024] 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.

[0025] The device further includes:

[0026] The first relay is connected in series in the main circuit where the neutral line of the motor is located;

[0027] The second relay is connected in series between the second end of the second bridge arm and the negative terminal;

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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

[0032] 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

[0033] A relay is connected in series between the second end of the first bridge arm and the positive terminal; and / or

[0034] A relay is connected in series between the second end of the second bridge arm and the negative terminal; and / or

[0035] 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

[0036] 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.

[0037] 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.

[0038] The battery charging and discharging device further includes:

[0039] The first relay is connected in series in the main circuit where the neutral line of the motor is located;

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] In an optional implementation, the charging interface is also used to connect an external load.

[0045] In an optional embodiment, the battery charging and discharging device further includes:

[0046] Electrical equipment components, including electrical equipment interfaces and power interfaces;

[0047] The electrical equipment interface is used to connect electrical equipment;

[0048] 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.

[0049] 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.

[0050] In an optional implementation, the second end of the first bridge arm is connected to the positive terminal.

[0051] The battery charging and discharging device further includes:

[0052] 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;

[0053] 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.

[0054] 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.

[0055] 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.

[0056] A second aspect of this utility model provides a new energy vehicle, comprising:

[0057] Power battery pack; and

[0058] A battery charging and discharging device; the battery charging and discharging device is the battery charging and discharging device provided in any of the first aspects above.

[0059] The battery charging and discharging device and new energy vehicle provided in any of the above embodiments of this utility model, through the cooperation of a charging interface, an electric drive assembly, and a 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, during the charging process using the inductor energy storage circuit, an external DC power supply can be used to charge the inductor, thereby raising its terminal voltage to above 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.

[0060] Furthermore, even if the output voltage and output current of the external DC power supply have various parameters, as can be seen from the above, as long as its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided in this utility model embodiment can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided in this utility model embodiment can also be compatible with charging piles with different parameters in this situation.

[0061] 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.

[0062] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1a This diagram shows a structural block diagram of a battery charging and discharging device according to an embodiment of the present invention.

[0065] Figure 1b This diagram illustrates a circuit schematic of a battery charging and discharging device according to an embodiment of the present invention.

[0066] Figure 2a This diagram shows a structural block diagram of another battery charging and discharging device provided in an embodiment of the present invention;

[0067] Figure 2b A circuit diagram of another battery charging and discharging device provided in an embodiment of the present invention is shown;

[0068] Figure 3 This diagram illustrates a circuit schematic of a battery charging and discharging device with direct charging function according to an embodiment of the present invention.

[0069] Figure 4a The circuit structure schematic diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor provided in an embodiment of the present invention is shown.

[0070] Figure 4b This diagram illustrates the circuit structure of another battery charging and discharging device with a first voltage-stabilizing capacitor provided in an embodiment of the present invention.

[0071] Figure 5a This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0072] Figure 5b This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0073] Figure 5c This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0074] Figure 5d This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0075] Figure 5e This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0076] Figure 5f This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0077] Figure 5g This diagram illustrates the circuit schematic of yet another battery charging and discharging device provided in this embodiment of the present invention.

[0078] Figure 6 This diagram illustrates a circuit schematic of a battery charging and discharging device with a battery preheating function according to an embodiment of the present invention.

[0079] Figure 7a This diagram illustrates a circuit schematic of a battery charging and discharging device connected to an internal load according to an embodiment of the present invention.

[0080] Figure 7b The circuit diagram of another battery charging and discharging device connected to an internal load provided by an embodiment of the present invention is shown.

[0081] 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

[0082] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0083] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0084] 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.

[0085] In the description of this utility model, it should be noted that when terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are mentioned, 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 utility model product is in use. They are used only for the convenience of describing this utility model 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 utility model. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0086] 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.

[0087] In this embodiment of the utility model, 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 utility model can be understood according to the specific circumstances.

[0088] 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 utility model provides a battery charging and discharging device. By utilizing a charging interface 100, an electric drive assembly 200, and a battery pack interface 300 in conjunction, an inductor energy storage circuit and a battery charging circuit are configured for the battery charging and discharging device. This allows the device to first charge the inductor in the electric drive assembly 200 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 300. 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, during the charging process using the inductor energy storage circuit, an external DC power supply can be used to charge the inductor, thereby raising its terminal voltage to above the charging voltage of the power battery pack. This ensures that even an external DC power supply with an output voltage lower than the charging voltage of the power battery pack can meet the battery charging requirements.

[0089] Furthermore, even if the output voltage and output current of the external DC power supply have various parameters, as can be seen from the above, as long as its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided in this utility model embodiment can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided in this utility model embodiment can also be compatible with charging piles with different parameters in this situation.

[0090] Furthermore, since the electric drive assembly 200 can reuse the electric drive assembly 200 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.

[0091] The following, combined with Figure 1a The battery charging and discharging device provided in the embodiments of this utility model will be described below. Please refer to [link to relevant documentation]. Figure 1a , Figure 1a This is a structural block diagram of a battery charging and discharging device provided in an embodiment of the present utility model; the battery charging and discharging device includes a charging interface 100, an electric drive assembly 200, and a battery pack interface 300.

[0092] The charging interface 100 is used to connect to an external DC power source, including a positive input terminal and a negative input terminal.

[0093] 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 a first end of the first bridge arm 210 and a first end of the second bridge arm 220, respectively; the neutral line of the motor M is connected to either the positive terminal or the 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.

[0094] The battery pack interface 300 has a first access terminal for connecting to the positive terminal of the power battery pack and connecting 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 connecting to the second end of the second bridge arm 220.

[0095] 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.

[0096] The inductor energy storage circuit is used to charge the inductor in the motor M. The inductor energy storage circuit includes the external DC power supply and the inductor.

[0097] 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.

[0098] The battery charging and discharging device provided in this 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.

[0099] Taking a new energy vehicle as an example, the battery charging and discharging device provided in this 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 the need for additional components. This can reduce the overall manufacturing cost of the charging and discharging device and improve the space utilization rate inside the vehicle.

[0100] The following uses the battery charging and discharging device provided in this embodiment of the present invention applied to a new energy vehicle as an example to illustrate the working principle of the battery charging and discharging device provided in this embodiment of the present invention:

[0101] 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.

[0102] 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 can have multiple wiring methods. In this embodiment of the utility model, two wiring methods are provided, which are described below. Figure 1a , Figure 1b , Figure 2a and Figure 2b To explain, Figure 1b This is a circuit diagram of a battery charging and discharging device provided in an embodiment of the present invention. Figure 2a This is a structural block diagram of another battery charging and discharging device provided in an embodiment of this utility model. Figure 2b Here is a circuit diagram of another battery charging and discharging device provided in this embodiment of the present invention:

[0103] 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.

[0104] In this case, there is no connection between the second end of the second bridge arm 220 and the negative terminal, such as Figure 1a As shown, 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.

[0105] 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.

[0106] The corresponding switching process between the inductor energy storage circuit and the battery charging circuit is as follows:

[0107] The controller first turns on the first bridge arm 210 and disconnects the second bridge arm 220. In this case, please refer to [link / reference needed]. 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, the inductor's terminal voltage is higher than the charging voltage of the power battery pack, thus achieving a voltage 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.

[0108] When the cycle of alternating on / off control is reached, it can be understood that when the on-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 turn on. In this case, please refer to [further details]. Figure 1b The current direction in the battery charging circuit is: inductor → power battery pack (battery pack 1 → battery pack 2) → second bridge arm 220 → inductor. During this process, because the inductor's terminal voltage is higher than the power battery pack's charging voltage, the inductor can charge the power battery pack. Therefore, 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.

[0109] Therefore, after the battery charging and discharging device is connected to the external DC power supply, the external DC power supply can be used to intermittently charge the inductor at low voltage by alternating on and off of the first bridge arm 210 and the second bridge arm 220, and then the power battery pack can be charged at boost voltage by intermittently through the inductor until the power battery pack is fully charged or the external DC power supply is disconnected.

[0110] 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.

[0111] In this case, there is no connection between the second end of the first bridge arm 210 and the positive terminal, such as Figure 2aAs shown, 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.

[0112] 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.

[0113] The corresponding switching process between the inductor energy storage circuit and the battery charging circuit is as follows:

[0114] 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, please refer to [link to relevant documentation]. Figure 2b The current direction in 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 inductor's terminal voltage has exceeded the charging voltage of the power battery pack, thus achieving a boost effect. The determination of the first duration can be found above and will not be repeated here.

[0115] When the alternating on / off control cycle is reached, it can be understood that when the on-time of the switch in the second bridge arm 220 reaches the first duration, the controller continues to keep the first bridge arm 210 off and controls the switch in the second bridge arm 220 to be off. In this case, please refer to [further details needed]. Figure 2b The current direction in 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, because 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. Therefore, 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.

[0116] Therefore, after the battery charging and discharging device is connected to the external DC power supply, the external DC power supply can be used to intermittently charge the inductor at low voltage by alternating switching of the switching transistor in the second bridge arm 220, and then the power battery pack can be charged at boost voltage intermittently by the inductor until the power battery pack is fully charged or the external DC power supply is disconnected.

[0117] 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, if 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. If the current in the circuit is small, the number of switching transistors turned on can be reduced.

[0118] In the above, Figure 1b and Figure 2b In the circuit schematic shown, all components except for the charging interface 100, the electric drive assembly 200, and the power battery pack 300 can be omitted, because the placement 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.

[0119] Although a controller is mentioned in this embodiment of the present invention, the relevant control scheme in the controller depends on the circuit composition of the battery charging and discharging device provided in this embodiment of the present invention. This circuit composition is the focus of protection in this embodiment of the present invention, while the relevant control scheme is not the focus of protection. Therefore, it should not be understood that this embodiment of the present invention involves method improvement.

[0120] Furthermore, for the convenience of the following description, in this embodiment of the present invention, the above charging mode is referred to as boost charging mode, and the corresponding scheme is boost charging scheme.

[0121] 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:

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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, the 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 by this embodiment 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.

[0126] 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 embodiment. Based on this, in some embodiments, the battery charging and discharging device provided in this embodiment can also have a direct charging mode. For this purpose, this embodiment provides the following two direct charging schemes:

[0127] The first direct charging solution:

[0128] 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.

[0129] Please continue reading. 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.

[0130] 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.

[0131] When the battery charging and discharging device provided by this utility model 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 [link to relevant documentation]. 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.

[0132] The second direct charging solution:

[0133] 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.

[0134] Please see Figure 3 , Figure 3 This is a circuit diagram of a battery charging and discharging device with direct charging function provided in an embodiment of the present invention. 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 of the present invention may further include:

[0135] The first relay K1 is connected in series in the main circuit where the neutral line of the motor M is located;

[0136] The second relay K2 is connected in series between the second end of the second bridge arm 220 and the negative terminal;

[0137] 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, the second relay K2 is in the closed state, and the external DC power supply and the power battery pack form a direct charging circuit.

[0138] When the battery charging and discharging device provided by this utility model 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 X. 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.

[0139] based on Figure 3 In the illustrated embodiment, 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.

[0140] 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.

[0141] 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.

[0142] In boost charging or buck-boost charging modes, the battery charging circuit may experience significant ripple current. This ripple current can affect battery lifespan and cause battery temperature rise, which in turn impacts battery performance. Therefore, to avoid the adverse effects of ripple current on battery lifespan and performance, in some embodiments, please refer to [the relevant documentation / reference needed]. Figure 4a , Figure 4a This is a circuit diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor C1 provided by an embodiment of the present invention. The battery charging and discharging device provided by this embodiment of the present invention may further include a first voltage-stabilizing capacitor C1, which is connected in parallel with the battery pack interface 300.

[0143] from Figure 4a As can be seen, the first voltage-stabilizing capacitor C1 is connected in parallel across the two ends of the battery pack interface 300. This indicates that the first voltage-stabilizing capacitor C1 and the battery pack interface 300 are interconnected. Therefore, on the one hand, at the moment the power battery pack is powered on, the first voltage-stabilizing capacitor C1 may spark, potentially causing the circuit to burn out. On the other hand, due to the presence of the power battery pack, the first voltage-stabilizing capacitor C1 will be charged. During the assembly process of the first voltage-stabilizing capacitor C1, assemblers or assembly components may be electrocuted due to the discharge of the first voltage-stabilizing capacitor C1, thus posing a certain assembly risk.

[0144] Therefore, to avoid arcing in the first voltage regulator capacitor C1 and to reduce the assembly risk of the first voltage regulator capacitor C1, in some embodiments, please refer to... Figure 4b , Figure 4b This is a circuit diagram of another battery charging and discharging device with a first voltage-stabilizing capacitor C1 provided by an embodiment of the present invention. The battery charging and discharging device provided by this embodiment can also be equipped with corresponding safety protection devices for the first voltage-stabilizing capacitor C1, that is, at least one end of the first voltage-stabilizing capacitor C1 is connected to the battery pack interface 300 via a relay. Figure 4b As can be seen, the two ends of the first voltage regulator capacitor C1 are connected to the battery pack interface 300 through the fourth relay K4 and relay Kc, respectively.

[0145] 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.

[0146] Based on the previous embodiment, in some embodiments, for further protection of battery and circuit safety, please continue to refer to... Figure 4bThe battery charging and discharging device provided in this 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.

[0147] 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 a set voltage difference value, the fourth relay K4 is in the off state and the fifth relay K5 is in the on state.

[0148] 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 on state and the fifth relay K5 is in the off state.

[0149] 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.

[0150] Based on any embodiment of the battery charging and discharging device of this utility model, including the first voltage stabilizing capacitor C1, in some embodiments, to achieve further isolation between the electric drive assembly 200 and the power battery pack, please continue to refer to... Figure 4a and Figure 4b The battery charging and discharging device provided in this embodiment may further include a relay Kd, which is connected in series between one end of the first voltage stabilizing capacitor C1 connected to the first access terminal and the first end of the first bridge arm 210.

[0151] 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.

[0152] Based on any of the above embodiments, to avoid affecting the motor drive due to the charging interface 100 being energized during driving, in some embodiments, please refer to... Figure 5a , Figure 5a This is a circuit diagram of another battery charging and discharging device provided in this embodiment of the present invention. The battery charging and discharging device provided in this embodiment of the present invention 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 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 between the neutral line and the negative terminal of the motor M, such as... Figure 5a As shown.

[0153] 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.

[0154] In addition, this utility model embodiment also provides various modified schemes for the combination of the control relay and the first voltage-stabilizing capacitor C1, such as... Figures 5b to 5g As shown, Figures 5b-5e These are circuit diagrams of another battery charging and discharging device provided in the embodiments of this utility model. Figures 5b-5e The diagram not only shows the combination of the first voltage-stabilizing capacitor C1 and the relay Ke, but also shows a variation of the relay's position in the circuit. Figure 5f and Figure 5g The diagram not only shows the combination of the first voltage-stabilizing capacitor C1 and the relay Ke, but also shows a scheme in which the position of the first relay K1 can be adaptively adjusted to save on relays.

[0155] In addition, Figures 5a to 5g Besides the example shown, there are other variations in the location of the node connecting the neutral line of motor M to the first access terminal. For example, it can be located between the first access terminal and the fourth relay K4.

[0156] 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.

[0157] 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.

[0158] In some embodiments, for improved circuit safety, please refer to [further details]. Figure 3 The battery charging and discharging device provided in this embodiment of the present invention may further include at least one of the following circuit safety configuration schemes:

[0159] 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;

[0160] The second type: A relay Kc 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;

[0161] The third type: A relay Ka is connected in series between the second end of the first bridge arm 210 and the positive terminal;

[0162] The fourth type: A relay is connected in series between the second end of the second bridge arm 220 and the negative terminal;

[0163] Fifth type: A main fuse A is connected in series between the first access end of the battery pack interface 300 and the second end of the first bridge arm 210;

[0164] 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.

[0165] Regarding the first circuit safety configuration scheme described above, based on the embodiment of the battery charging and discharging device including the fourth relay K4 provided in this utility model, 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.

[0166] 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.

[0167] Regarding the fourth safety configuration scheme described above, based on the embodiment of the battery charging and discharging device including the second relay K2 provided in this utility model, 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.

[0168] 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.

[0169] Because battery temperature decreases to some extent in low-temperature environments, it affects battery performance, such as power supply performance and charging speed. Therefore, to ensure the performance of the power battery pack in low-temperature environments, in some embodiments, the battery charging and discharging device provided by this utility model can also have a battery preheating function. Please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a circuit diagram of a battery charging and discharging device with battery preheating function provided by an embodiment of the present utility model. 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.

[0170] Accordingly, the battery charging and discharging device provided in this embodiment of the present invention may further include:

[0171] The first relay K1 is connected in series in the main circuit where the neutral line of the motor M is located;

[0172] The third relay K3 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 M and the first relay K1.

[0173] When the temperature of the power battery pack is lower than the set temperature threshold, the first relay K1 is in the off state and the third relay K3 is in the on 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 precharge circuit, thereby raising the temperature of the power battery pack.

[0174] 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 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.

[0175] In the battery precharge 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.

[0176] Although Figure 6 In the circuit shown, one end of the third relay K3 is connected to the midpoint of the voltage of the multiple battery packs contained 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, then the midpoint of the voltage represents the midpoint of the connection between 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.

[0177] 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.

[0178] When the temperature of the power battery pack is lower than a set temperature threshold, the first relay K1 is in the off state and the third relay K3 is in the on 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 precharge circuit, thereby raising the temperature of the power battery pack.

[0179] 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 that is not short-circuited discharges to the inductor.

[0180] by Figure 6 Taking the example shown, 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.

[0181] In this situation, both the first relay K1 and the second bridge arm 220 are in the off state.

[0182] 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.

[0183] by Figure 6 As shown in the 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.

[0184] In this situation, the first relay K1, the fourth relay K4, and the first bridge arm 210 are all in the open state.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] In some embodiments, to improve the practicality of the battery charging and discharging device, the battery charging and discharging device provided in this utility model embodiment can also charge electrical equipment. The electrical equipment can refer to the electrical equipment contained within the battery charging and discharging device as a power source, and can also be referred to as an internal load, which can be a high-voltage internal load. Based on this, the battery charging and discharging device provided in this utility model embodiment may further include:

[0189] Electrical equipment components, including electrical equipment interfaces and power interfaces;

[0190] The electrical equipment interface is used to connect electrical equipment;

[0191] 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 from the power battery pack for charging and discharging through the battery pack interface 300.

[0192] For applications where battery charging and discharging devices are connected to high-voltage loads, this utility model provides various implementation methods for connecting battery charging and discharging devices to high-voltage loads. Please refer to [link to relevant documentation]. Figure 7a and Figure 7b , Figure 7a and Figure 7b The circuit diagrams of a battery charging and discharging device connected to an internal load provided in the embodiments of this utility model present two different variations. These two variations are essentially divided into two categories:

[0193] Category 1: Internal loads draw power from an external DC power source, such as... Figure 7a As shown.

[0194] Category 2: Internal loads draw power from the battery pack, such as... Figure 7b As shown.

[0195] 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.

[0196] In driving conditions, i.e., when the power battery pack supplies power to the electric drive assembly 200, to avoid a large instantaneous voltage being generated in the circuit at the moment the connection between the power battery pack and the electric drive assembly 200 is established, which could impact the motor M of the electric drive assembly 200 and thus affect the performance or lifespan of the motor M, in some embodiments, please refer to... Figure 1b The electric drive assembly 200 may also include a second voltage regulator capacitor C2, the two ends of which are respectively connected to the second end of the first bridge arm 210 and the second end of the second bridge arm 220.

[0197] 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.

[0198] 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 by this utility model 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.

[0199] Based on this, the second end of the first bridge arm 210 is connected to the positive terminal.

[0200] Accordingly, the battery charging and discharging device provided in this embodiment of the present invention may further include:

[0201] 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;

[0202] The pre-charging circuit includes a resistor R connected in series with a fifth relay K5; the pre-charging circuit is connected in parallel with the fourth relay K4;

[0203] When the difference between the terminal voltage of the second voltage stabilizing capacitor C2 and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference value, the fourth relay K4 is in the open state and the fifth relay K5 is in the closed state.

[0204] When the difference between the terminal voltage of the second voltage-stabilizing 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.

[0205] by Figure 1b For 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.

[0206] 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.

[0207] The voltage difference can be set based on experiments or experience, for example, 5V, but is not limited to this.

[0208] Corresponding to the embodiments of the battery charging and discharging device, this utility model embodiment also provides a new energy vehicle, including:

[0209] Vehicle body; and

[0210] A battery charging and discharging device is installed on the vehicle body; the battery charging and discharging device is the battery charging and discharging device in any of the above embodiments.

[0211] 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 by this utility model, and will not be repeated here.

[0212] It is worth noting that the technical features or technical solutions in any of the above embodiments of this utility model can be combined or integrated with each other, as long as there is no contradiction in the combination or integration.

[0213] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

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 is the battery charging and discharging device according to any one of claims 1 to 14.

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