Battery charging and discharging device and new energy automobile

Abstract

The embodiment of the invention provides a battery charging and discharging device and a new energy automobile, and the 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] The present invention relates to the field of new energy vehicles, and in particular to a battery charging and discharging device and a new energy vehicle. Background Art

[0002] New energy vehicles are a rapidly developing means of transportation in recent years, and have attracted widespread attention for their environmental protection and energy-saving features. New energy vehicles mainly include pure electric vehicles and plug-in hybrid vehicles, both of which use electricity as their main power source and have lower emissions and higher energy efficiency than traditional fuel vehicles.

[0003] However, with the popularization of new energy vehicles, charging problems have gradually become prominent. For example, when the output voltage of the charging pile is lower than the charging voltage of the battery, the new energy vehicles in the related technology cannot use the output voltage to charge the battery, which in turn leads to the inability to meet the user's charging needs for new energy vehicles, seriously affecting the user experience. Summary of the invention

[0004] In view of this, in order to at least solve the technical problem in the related art that the output voltage of the charging pile is lower than the battery charging voltage and cannot meet the battery charging demand, the purpose of the present invention is to provide a battery charging and discharging device and a new energy vehicle.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0006] According to a first aspect of an embodiment of the present invention, a battery charging and discharging device is provided, comprising:

[0007] A charging interface, used to connect to an external DC power source, including a positive terminal and a negative terminal;

[0008] An electric drive assembly, comprising a motor, a first bridge arm and a second bridge arm; each phase line of the motor is connected to the first end of the first bridge arm and the first end of the second bridge arm respectively, and the neutral line of the motor is connected to the positive electrode access terminal or the negative electrode access terminal; the second end of the first bridge arm is connected to the positive electrode access terminal, and / or the second end of the second bridge arm is connected to the negative electrode access terminal;

[0009] A battery pack interface, wherein a first access end for accessing the positive electrode of the power battery pack is connected to the neutral line of the motor, and a second access end for accessing the negative electrode of the power battery pack is connected 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 alternately turned on and off, or the second bridge arm is alternately turned on and off, so as to alternately switch the inductive energy storage circuit and the battery charging circuit;

[0011] The inductive energy storage circuit is used to charge the inductance in the motor, and the inductive energy storage circuit includes the external DC power supply and the inductance;

[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 time period each time it is turned on;

[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 lower than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm are alternately turned on and off, or the second bridge arm is alternately turned on and off, so as 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 time period each time it is turned on;

[0015] The first duration is greater than the second duration.

[0016] In an optional embodiment, the neutral line of the motor is connected to the negative electrode access terminal; the second end of the first bridge arm is connected to the positive electrode access terminal;

[0017] In the inductive energy storage circuit, the first bridge arm is in an on state, and the second bridge arm is in an off state;

[0018] In the battery charging circuit, the first bridge arm is in a disconnected state, and the second bridge arm is in a conductive state.

[0019] In an optional embodiment, the neutral line of the motor is connected to the positive electrode access terminal; the second end of the second bridge arm is connected to the negative electrode access terminal;

[0020] In the inductive energy storage circuit, the first bridge arm is in a disconnected state, the switch tube in the second bridge arm is in a conducting state, and the diode in the second bridge arm is in a cut-off state;

[0021] In the battery charging circuit, the first bridge arm is in a disconnected state, the switch tube in the second bridge arm is in a disconnected state, and the diode in the second bridge arm is in a conducting 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 a disconnected state, the second bridge arm is in a conductive state, and the external DC power supply, the power battery pack and the inductor form a direct charging loop.

[0024] In an optional embodiment, the second end of the first bridge arm is connected to the positive electrode access terminal, and the second end of the second bridge arm is connected to the negative electrode access terminal;

[0025] The device also includes:

[0026] A first relay is connected in series to a trunk line where a neutral line of the motor is located;

[0027] A second relay is connected in series between the second end of the second bridge arm and the negative electrode access end;

[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 disconnected state, the second relay is in the on 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 to the battery pack interface.

[0030] In an optional embodiment, 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 implementation manner, a relay is connected in series between the first access end 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 end 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 electrode access end; and / or

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

[0035] A main fuse is connected in series between the first access end 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 end 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 electrode access terminal, and the second end of the second bridge arm is connected to the negative electrode access terminal;

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

[0039] A first relay is connected in series to a trunk line where a neutral line of the motor is located;

[0040] a third relay, one end of which is connected between the plurality of 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;

[0041] When the temperature of the power battery pack is lower than a set temperature threshold, the first relay is in an off state, the third relay is in an on 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 to achieve heating of the power battery pack;

[0042] In the battery discharge circuit, the first bridge arm is in an on state, the second bridge arm is in an off state, the first battery group in the power battery pack is short-circuited by the third relay, and the second battery group in the power battery pack that is not short-circuited discharges to the inductor;

[0043] In the battery pre-charging circuit, the first bridge arm is in a disconnected state, the second bridge arm is in a conductive state, and the first battery pack is charged by the inductor.

[0044] In an optional implementation, the charging interface is also used to connect to 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 power-consuming device interface is used to access the power-consuming device;

[0048] The power interface is connected to the charging interface or the battery pack interface, and is used to introduce an external DC power supply 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-stabilizing capacitor, and two ends of the second voltage-stabilizing capacitor 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 embodiment, the second end of the first bridge arm is connected to the positive electrode access end;

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

[0052] a fourth relay, connected in series between the first access end of the battery pack interface and the second end of the first bridge arm;

[0053] a pre-charging circuit, comprising 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 stabilizing capacitor and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference, the fourth relay is in an off state and the fifth relay is in an 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, the fourth relay is in an on state and the fifth relay is in an off state.

[0056] A second aspect of an embodiment of the present invention provides a new energy vehicle, including:

[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 one of the first aspects above.

[0059] The battery charging and discharging device and new energy vehicle provided by any of the above aspects of the embodiments of the present invention, by using the charging interface, the electric drive assembly and the battery pack interface to cooperate, configure the battery charging and discharging device with an inductive energy storage circuit and a battery charging circuit, so that 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, the inductor in the electric drive assembly is first charged through the inductive energy storage circuit, so that the inductor continuously stores energy until the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, and then the inductor is used to charge the power battery pack through the battery charging circuit. It can be seen that in the process of charging the inductor using the inductive energy storage circuit, the inductor can be charged by using an external DC power supply, and then the terminal voltage of the inductor can be increased to a level higher than the charging voltage of the power battery pack, thereby realizing an external DC power supply with an output voltage lower than the charging voltage of the power battery pack, which can also meet the charging requirements of the battery.

[0060] In addition, even if the output voltage and output current of the external DC power supply have multiple parameters, it can be seen from the above that as long as its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided by the embodiment of the present invention can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided by the embodiment of the present invention 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 of the new energy vehicle, it can also reduce the manufacturing cost of the battery charging and discharging device and the new energy vehicle, and improve the space utilization rate in the vehicle.

[0062] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0064] Figure 1a A structural block diagram of a battery charging and discharging device provided by an embodiment of the present invention is shown;

[0065] Figure 1b A circuit schematic diagram of a battery charging and discharging device provided by an embodiment of the present invention is shown;

[0066] Figure 2a A structural block diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

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

[0068] Figure 3 A circuit schematic diagram of a battery charging and discharging device with a direct charging function provided by an embodiment of the present invention is shown;

[0069] Figure 4a A 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 A circuit structure principle diagram of another battery charging and discharging device with a first voltage stabilizing capacitor provided in an embodiment of the present invention is shown;

[0071] Figure 5aA circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0072] Figure 5b A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0073] Figure 5c A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0074] Figure 5d A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0075] Figure 5e A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0076] Figure 5f A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0077] Figure 5g A circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention is shown;

[0078] Figure 6 A circuit schematic diagram of a battery charging and discharging device with a battery preheating function provided by an embodiment of the present invention is shown;

[0079] Figure 7a A circuit schematic diagram of a battery charging and discharging device connected to an internal load provided by an embodiment of the present invention is shown;

[0080] Figure 7b A circuit schematic 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-resistance, C1-first voltage-stabilizing capacitor, C2-second voltage-stabilizing capacitor, A-main fuse, B-shunt. DETAILED DESCRIPTION

[0082] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here 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 invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0084] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0085] In the description of the present invention, it should be noted that if terms such as orientation are mentioned, for example, "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the corresponding drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0086] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or suspended, but 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 the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connection", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0088] In order to at least solve the technical problem in the related art that the output voltage of the charging pile is lower than the battery charging voltage and the battery charging demand cannot be met, an embodiment of the present invention provides a battery charging and discharging device, which is configured with an inductor energy storage circuit and a battery charging circuit for the battery charging and discharging device by using the charging interface 100, the electric drive assembly 200 and the battery pack interface 300 to cooperate, so that when the output voltage of the external DC power supply connected to the charging connection is lower than the charging voltage of the power battery pack connected to the battery pack interface 300, the inductor in the electric drive assembly 200 is first charged through the inductor energy storage circuit, so that the inductor continuously stores energy until the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, and then the inductor is used to charge the power battery pack through the battery charging circuit. It can be seen that in the process of charging the inductor using the inductor energy storage circuit, the inductor can be charged by using the external DC power supply, and then the terminal voltage of the inductor is increased to a level higher than the charging voltage of the power battery pack, thereby realizing an external DC power supply with an output voltage lower than the charging voltage of the power battery pack, which can also meet the charging demand of the battery.

[0089] In addition, even if the output voltage and output current of the external DC power supply have multiple parameters, it can be seen from the above that as long as its output voltage is lower than the charging voltage of the power battery pack, the battery charging and discharging device provided by the embodiment of the present invention can be used to charge the power battery pack. Therefore, the battery charging and discharging device provided by the embodiment of the present invention 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 the new energy vehicle, it can also reduce the manufacturing cost of the battery charging and discharging device and the new energy vehicle, and improve the space utilization rate in the vehicle.

[0091] The following, combined Figure 1a For a description of the battery charging and discharging device provided in the embodiment of the present invention, please refer to Figure 1a , Figure 1a It is a structural block diagram of a battery charging and discharging device provided in an embodiment of the present invention; 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, and includes a positive terminal and a negative 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 the first end of the first bridge arm 210 and the first end of the second bridge arm 220 respectively, and the neutral line of the motor M is connected to the positive electrode access terminal or the negative electrode access terminal; the second end of the first bridge arm 210 is connected to the positive electrode access terminal, and / or the second end of the second bridge arm 220 is connected to the negative electrode access terminal;

[0094] A battery pack interface 300, a first access end for accessing the positive electrode of the power battery pack is connected to the neutral line of the motor M, and a second access end for accessing the negative electrode of the power battery pack is connected 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 alternately turned on and off, or the second bridge arm 220 is alternately turned on and off to alternately switch the inductive energy storage circuit and the battery charging circuit;

[0096] The inductive energy storage circuit is used to charge the inductance in the motor M, and the inductive energy storage circuit includes the external DC power supply and the inductance;

[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 the embodiment of the present invention can be sold as a separate product or as part of a carrier using a battery as a power energy source, wherein the carrier may include but is not limited to new energy vehicles, new energy aircraft or other new energy vehicles.

[0099] Taking the carrier as a new energy vehicle as an example, the battery charging and discharging device provided in the embodiment of the present invention reuses the electric drive assembly 200 of the new energy vehicle. It is possible to charge the power battery pack with a low-voltage DC power supply (a DC power supply whose output voltage is lower than the charging voltage of the power battery pack) without setting up other components. This can reduce the manufacturing cost of the entire vehicle of the charging and discharging device and improve the space utilization rate in the vehicle.

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

[0101] When the charging and discharging device is applied to a new energy vehicle, the power battery pack can be connected to the battery pack interface 300. Therefore, when the power battery pack of the new energy vehicle needs to be charged, the charging interface 100 of the battery charging and discharging device can be connected to an external DC power source, for example, the charging interface 100 is connected to a charging pile. Subsequently, the controller in the new energy vehicle can obtain the output voltage of the external DC power source currently connected to the charging interface 100 through relevant technologies, 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, in order to meet the charging requirements of the power battery pack, the relevant components in the circuit structure of the battery charging and discharging device involved may have multiple wiring modes. In the embodiment of the present invention, two wiring modes are provided. Figure 1a , Figure 1b , Figure 2a and Figure 2b To explain, Figure 1b is a circuit schematic diagram of a battery charging and discharging device provided by an embodiment of the present invention, Figure 2a is a structural block diagram of another battery charging and discharging device provided by an embodiment of the present invention, Figure 2b This is a circuit diagram of another battery charging and discharging device provided by an embodiment of the present invention:

[0103] The first type: the neutral line of the motor M is connected to the negative electrode access terminal, and the second end of the first bridge arm 210 is connected to the positive electrode access terminal.

[0104] In this case, there is no connection relationship between the second end of the second bridge arm 220 and the negative electrode access terminal. Figure 1a As shown, or, a relay may be provided between the second end of the second bridge arm 220 and the negative electrode access end, but the relay is in an off state to ensure the normal operation of the inductive energy storage circuit and the battery charging circuit, and a certain circuit isolation can also be achieved through the relay. Based on this, the controller controls the first bridge arm 210 and the second bridge arm 220 to be alternately turned on and off to alternately switch the inductive energy storage circuit and the battery charging circuit. That is, in the inductive energy storage circuit, the first bridge arm 210 is in a conducting state, and the second bridge arm 220 is in a disconnected state; in the battery charging circuit, the first bridge arm 210 is in a disconnected state, and the second bridge arm 220 is in a conducting state. Among them, the second bridge arm 220 is in a conducting state, which may 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. On this basis, the switch tube in the second bridge arm 220 may be further controlled to be turned on, or the switch tube in the second bridge arm 220 may not be controlled to be turned on.

[0105] In some examples, the controller may control the first bridge arm 210 and the second bridge arm 220 to be alternately switched on and off at a set frequency, wherein the set frequency may be obtained based on experience or experiments, for example, may be set to 100,000 times / second.

[0106] The corresponding alternating switching process of the inductive energy storage circuit and the battery charging circuit is as follows:

[0107] The controller first controls the first bridge arm 210 to be turned on and the second bridge arm 220 to be turned off. In this case, please refer to Figure 1b, the current direction of the inductor energy storage circuit is: external DC power supply positive electrode → first bridge arm 210 → inductor → external DC power supply negative electrode → external DC power supply positive electrode. In this process, the external DC power supply continuously charges the inductor. After reaching the first time length, it indicates that the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, thereby achieving a boost effect. The first time length can be determined by the controller according to the charging voltage of the power battery pack and the output voltage of the external DC power supply. For details, please refer to the relevant technology, which will not be explained in detail here.

[0108] When the cycle of the alternating on-off control is reached, it can be understood that when the conduction time of the first bridge arm 210 reaches the first time, the controller controls the first bridge arm 210 to be disconnected and the second bridge arm 220 to be turned on. In this case, please continue to 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. In 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 also meet the charging requirements of the power battery pack.

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

[0110] The second type: the neutral line of the motor M is connected to the positive electrode access terminal, and the second end of the second bridge arm 220 is connected to the negative electrode access terminal.

[0111] In this case, there is no connection relationship between the second end of the first bridge arm 210 and the positive electrode access terminal. Figure 2a As shown, or, a relay can be provided between the second end of the first bridge arm 210 and the positive electrode access end, but the relay is in a disconnected state to ensure the normal operation of the inductive energy storage circuit and the battery charging circuit, and a certain circuit isolation can also be achieved through the relay. The controller does not need to pay attention to the first bridge arm 210, but mainly pays attention to the control of the second bridge arm 220, that is, whether in the inductive energy storage circuit or in the battery charging circuit, the first bridge arm 210 is in a disconnected state, and the second bridge arm 220 is in an alternating on-off state - in the inductive energy storage circuit, the first bridge arm 210 is in a disconnected state, the switch tube in the second bridge arm 220 is in a conducting state, and the diode in the second bridge arm 220 is in a cut-off state; in the battery charging circuit, the first bridge arm 210 is in a disconnected state, the switch tube in the second bridge arm 220 is in a disconnected 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 on and off of the switch tubes in the second bridge arm 220 at a set frequency.

[0113] The corresponding alternating switching process of the inductive 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 switch tube of the second bridge arm 220 turned on. In this case, please refer to Figure 2b , the current direction of the inductor energy storage circuit is: external DC power supply positive electrode → inductor → switch tube of the second bridge arm 220 → external DC power supply negative electrode → external DC power supply positive electrode. In this process, the external DC power supply continuously charges the inductor. After reaching the first duration, it means that the terminal voltage of the inductor is higher than the charging voltage of the power battery pack, thereby achieving a voltage boost effect. The acquisition of the first duration can be found in the above record, which will not be repeated here.

[0115] When the cycle of the alternating on-off control is reached, it can be understood that when the on-time of the switch tube of the second bridge arm 220 reaches the first time length, the controller continues to keep the first bridge arm 210 off and controls the switch tube of the second bridge arm 220 to be off. In this case, please continue to 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. In 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 also meet the charging requirements of the power battery pack.

[0116] Therefore, after the battery charging and discharging device is connected to the above-mentioned external DC power supply, the external DC power supply can intermittently charge the inductor at a low voltage by alternating on and off the switch tube in the second bridge arm 220, and then intermittently boost charge the power battery pack through the inductor until the power battery pack is fully charged or the external DC power supply is disconnected.

[0117] In addition, when the first bridge arm 210 and / or the second bridge arm 220 includes multiple switch tubes, if the first bridge arm 210 or the second bridge arm 220 is turned on, the number of switch tubes turned on in the first bridge arm 210 or the second bridge arm 220 can be adjusted according to the current size in the loop. For example, when the current in the loop is large, the number of switch tubes turned on can be increased to achieve the purpose of current diversion, so as to avoid the current passing through the switch tube being too large and causing the switch tube to overheat or even be damaged. When the current in the loop is small, the number of switch tubes turned on can be reduced.

[0118] In the above, Figure 1b and Figure 2b In the circuit schematic diagram shown, other components except the charging port 100, the electric drive assembly 200 and the power battery pack 300 can be omitted, because the layout of these other components is designed to achieve other circuit functions and belongs to other variations. For details, please refer to the relevant records below.

[0119] In addition, for the convenience of the following description, in the embodiment of the present invention, the above charging mode is referred to as the boost charging mode, and the scheme corresponding to the charging mode is the boost charging scheme.

[0120] Since the external DC power supply may be a high-voltage and low-current type power supply, the high-voltage and low-current type may refer to that 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 this case, in order to improve the charging speed of the power battery pack, the battery charging and discharging device in any of the above embodiments may 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 less than the charging time of the inductor in the above boost charging mode. The corresponding buck-and-current boost charging mode is as follows:

[0121] 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 turned on and off, or the second bridge arm 220 is alternately turned 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 period of time each time it is turned on.

[0122] The second duration is greater than the first duration. As can be seen from the above, the first duration refers to the duration of charging the inductor during each conduction of the inductor energy storage circuit when the output voltage of the external DC power supply is lower than the charging voltage of the power battery pack.

[0123] The switching principle of the inductive energy storage circuit and the battery charging circuit can be found in the above related records and will not be elaborated here.

[0124] 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 external DC power supply can be bucked in the process of charging the inductor by using the inductive energy storage circuit - the output voltage of the external DC power supply is distributed to the inductor, so as to reduce the voltage output by the external DC power supply to the charging voltage required by the power battery pack, and at the same time, the current of the external DC power supply is fully pulled - that is, the maximum output current of the external DC power supply can be reached. Therefore, in the process of charging the power battery pack by using the battery charging circuit, since the charging power of the external DC power supply remains unchanged, the overall charging power of the battery charging circuit also remains unchanged, and the power is equal to the product of the voltage and the current, so the decrease in the charging voltage can increase the charging current, thereby achieving the purpose of increasing the charging current of the power battery pack, and the charging speed can be increased. It can be seen that the battery charging and discharging device provided by the embodiment of the present invention not only has the function of boost charging, but also has the function of buck-boost charging, and has stronger charging pile compatibility and practicality.

[0125] In addition to the two types of external DC power supplies mentioned above, there are also external DC power supplies whose output voltage is higher than the charging voltage of the power battery pack and whose output current is greater than or equal to the maximum charging current of the power battery pack. In this case, in order 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, which is also conducive to further improving the compatibility and practicality of the battery charging and discharging device provided by the embodiment of the present invention. Based on this, in some embodiments, the battery charging and discharging device provided by the embodiment of the present invention can also have a direct charging mode. In this regard, the embodiment of the present invention provides the following two direct charging schemes:

[0126] The first direct charging solution:

[0127] In the first direct charging scheme, it can be realized by adding a connection line on the basis of the boost charging scheme, without adding other devices, the circuit is simple and the cost is low.

[0128] Please continue reading Figure 1a or Figure 1b , the first access end of the battery pack interface 300 is also connected to the second end of the first bridge arm 210 , that is, a connection line is added to connect the first access end and the second end of the first bridge arm 210 .

[0129] 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 a disconnected state and the second bridge arm 220 is in a conductive state, and the external DC power supply, the power battery pack and the inductor form a direct charging loop.

[0130] When the battery charging and discharging device provided by the present invention 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 the direct charging mode is determined to be executed according to the comparison result, the first bridge arm 210 is controlled or kept disconnected and the second bridge arm 220 is turned on, thereby turning on the direct charging circuit. Please refer to Figure 1b The current direction of the direct charging circuit is: the positive electrode of the external DC power supply → the power battery pack (battery pack 1 → battery pack 2) → the second bridge arm 220 → the inductor → the negative electrode of the external DC power supply → the positive electrode of the external DC power supply.

[0131] The second direct charging solution:

[0132] It can be seen from the first scheme mentioned above that the direct charging circuit includes a part of the electric drive assembly 200, and in the second direct charging scheme, a direct charging circuit that does not include the electric drive assembly 200 can be provided on the basis of any of the above embodiments, which can save charging energy consumption and reduce heat loss to a certain extent.

[0133] See also Figure 3 , Figure 3 It is a circuit schematic diagram of a battery charging and discharging device with a direct charging function provided in an embodiment of the present invention, wherein the second end of the first bridge arm 210 is connected to the positive electrode access end, and the second end of the second bridge arm 220 is connected to the negative electrode access end.

[0134] Accordingly, the battery charging and discharging device provided in the embodiment of the present invention may further include:

[0135] A first relay K1 is connected in series to the trunk line where the neutral line of the motor M is located;

[0136] A second relay K2, connected in series between the second end of the second bridge arm 220 and the negative electrode access end;

[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 disconnected state, and the second relay K2 is in the on 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 the present invention 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 it is determined to execute the direct charging mode according to the comparison result, the first relay K1, the first bridge arm 210 and the second bridge arm 220 are controlled or kept disconnected, and the second relay K2 is controlled to be turned on, thereby turning on the direct charging circuit. Please continue to refer to Figure X. The current direction of the direct charging circuit is: the positive electrode of the external DC power supply → the power battery pack (battery pack 1 → battery pack 2) → the second relay K2 → the negative electrode of the external DC power supply → the positive electrode of the external DC power supply.

[0139] based on Figure 3 In the embodiment shown, when the battery charging and discharging device operates in the boost charging mode or the buck-and-current 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 the boost charging mode or the buck-and-current boost charging mode. The control principle of the first bridge arm 210 and the second bridge arm 220 can be found in the above related records and will not be described here.

[0140] It can be seen that the configuration of the first relay K1 and the second relay K2 can make the boost charging mode, the buck-and-current boost charging mode and the direct charging mode independent of each other, and can make the battery charging and discharging device compatible with more charging piles with different parameters, with 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 improve the charging speed.

[0142] In the boost charging mode or the buck-boost charging mode, the battery charging circuit may have a large ripple current, and the ripple current will affect the battery life 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 the ripple current on the battery life and battery performance, in some embodiments, refer to Figure 4a , Figure 4a It is a circuit structure principle diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor C1 provided in an embodiment of the present invention. The battery charging and discharging device provided in an embodiment of the present invention may also include a first voltage-stabilizing capacitor C1, and the first voltage-stabilizing capacitor C1 is connected in parallel with the battery pack interface 300.

[0143] from Figure 4aIt can be seen that the first voltage-stabilizing capacitor C1 is connected in parallel to both ends of the battery pack interface 300. It can be seen that the first voltage-stabilizing capacitor C1 and the battery pack interface 300 are connected. In this way, on the one hand, at the moment when the power battery pack is powered on, the first voltage-stabilizing capacitor C1 may spark, which may lead to the risk of burning out the circuit; on the other hand, due to the existence of the power battery pack, the first voltage-stabilizing capacitor C1 will be charged, and during the assembly process of the first voltage-stabilizing capacitor C1, the assembler or the assembled device may be electrocuted due to the discharge of the first voltage-stabilizing capacitor C1, which may lead to certain assembly risks.

[0144] Therefore, in order to avoid the sparking phenomenon of the first voltage stabilizing capacitor C1 and reduce the assembly risk of the first voltage stabilizing capacitor C1, in some embodiments, refer to Figure 4b , Figure 4b This 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 the present invention. The battery charging and discharging device provided by an embodiment of the present invention can also be equipped with a corresponding safety protection device 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. 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.

[0145] Therefore, when the battery charging and discharging device is not in working state, the relay between the first voltage stabilizing capacitor C1 and the battery pack interface 300 can be disconnected, so that the first voltage stabilizing capacitor C1 is not charged, which can reduce the assembly risk and avoid sparking.

[0146] Based on the above embodiment, in some embodiments, to further protect the battery and circuit safety, please continue to refer to Figure 4b The battery charging and discharging device provided in the embodiment of the present invention 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 stabilizing 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 an off state, and the fifth relay K5 is in an on state;

[0148] When the difference between the terminal voltage of the first stabilizing capacitor C1 and the terminal voltage of the power battery pack is less than the set voltage difference, the fourth relay K4 is in the on state, and the fifth relay K5 is in the off state.

[0149] Because under the driving condition, that is, when the power battery pack supplies power to the electric drive assembly 200, when the path between the power battery pack and the electric drive assembly 200 is turned on, a large instantaneous voltage is generated in the circuit, which impacts the motor M of the electric drive assembly 200, thereby affecting the performance or life of the motor M, and also affecting the normal use of the entire circuit. Therefore, the above-mentioned pre-charging circuit plays a role in the circuit, and after the terminal voltage of the electric drive system assembly is stabilized, the power battery pack is used to supply power to the electric drive system assembly, thereby effectively avoiding the impact of the instantaneous voltage on the electric drive assembly 200, which is conducive to improving the circuit safety.

[0150] Based on any embodiment of the present invention in which the battery charging and discharging device includes the first voltage stabilizing capacitor C1, in some embodiments, to further isolate the electric drive assembly 200 from the power battery pack, please continue to refer to Figure 4a and Figure 4b The battery charging and discharging device provided in the embodiment of the present invention 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 end 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-stabilizing capacitor C1 and the terminal voltage of the power battery pack is greater than or equal to the set voltage difference, 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-stabilizing capacitor C1 and the terminal voltage of the power battery pack is less than the set voltage difference, the relay Kd can be turned on. At the same time, the external DC power supply and the electric drive assembly 200 can also be isolated, effectively avoiding the impact of the external DC power supply on the electric drive assembly 200, and 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, in order to avoid affecting the motor drive due to the charging interface 100 being charged under driving conditions, in some embodiments, refer to Figure 5a , Figure 5a 1 is a circuit schematic diagram of another battery charging and discharging device provided by an embodiment of the present invention. The battery charging and discharging device provided by an 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 access terminal, the relay Ke is connected in series to the branch section between the neutral line of the motor M and the positive access terminal; when the neutral line of the motor M is connected to the negative access terminal, the relay Ke is connected in series to the branch section between the neutral line of the motor M and the negative access terminal, such as Figure 5a shown.

[0153] Therefore, under the driving condition, the controller can control the relay Ke to be disconnected so that the charging interface 100 is not powered, thereby avoiding the influence of the external DC power supply on the motor drive, which is beneficial to improving the driving reliability of the motor M.

[0154] In addition, the embodiment of the present invention also provides a variety of variations of the combination of the control relay and the first voltage stabilizing capacitor C1, such as Figure 5b to Figure 5g As shown, Figure 5b to Figure 5e All of them are circuit principle diagrams of another battery charging and discharging device provided by the embodiments of the present invention. Figure 5b to Figure 5e In FIG. 1 , not only the combination scheme of the first voltage stabilizing capacitor C1 and the relay Ke is shown, but also the variation scheme of the position of the relay in the circuit is shown. Figure 5f and Figure 5g In FIG. 1 , not only the combination scheme of the first voltage stabilizing capacitor C1 and the relay Ke is shown, but also a scheme of adaptively adjusting the position of the first relay K1 in order to save relays is shown.

[0155] In addition, Figure 5a to Figure 5g In addition to the example shown, there may be other variations in the location of the node where the neutral line of the motor M is connected to the first access terminal. For example, it may be located between the first access terminal and the fourth relay K4.

[0156] The combination of the relay Ke and the first voltage-stabilizing capacitor C1 can not only avoid the influence of the external DC power supply on the driving of the motor M, but also avoid the impact of the 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] Although more examples of the combination of the first voltage-stabilizing capacitor C1 and the relay Ke are provided above, in other variations, the relay Ke and the components other than the electronic components required to realize the boost charging function can be deleted, and at least one of these deletable components can be combined with the relay Ke and the electronic components required to realize the boost charging function. The same is true for the relevant examples in the full text, as long as there is no contradiction or logical error in the technical solution.

[0158] In some embodiments, to improve circuit safety, please continue to refer to Figure 3 The battery charging and discharging device provided in the embodiment of the present invention may also 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 end of the battery pack interface 300 and the second end of the first bridge arm 210;

[0160] The second type: a relay Kc is connected in series between the second access end 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 electrode access end;

[0162] Fourth type: a relay is connected in series between the second end of the second bridge arm 220 and the negative electrode access end;

[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 end of the battery pack interface 300 and the second end of the second bridge arm 220 .

[0165] For the first circuit safety configuration scheme, based on the embodiment of the present invention in which the battery charging and discharging device includes the fourth relay K4, the configured relay can reuse the fourth relay K4, which is beneficial to reducing the circuit configuration cost. Of course, it is also possible not to reuse the existing device, but to configure a corresponding relay separately.

[0166] The relays configured in the above-mentioned first and second circuit safety configuration schemes can both serve to isolate one end of the battery pack interface 300 and the electric drive assembly 200, and also have the functions of the relay itself, 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 failures and losses caused by overload or short circuit.

[0167] For the fourth safety configuration scheme, based on the embodiment of the present invention in which the battery charging and discharging device includes the second relay K2, the configured relay can reuse the second relay K2, which is beneficial to reducing the circuit configuration cost. 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 as described above. In addition, since the relays between any bridge arm and the charging interface 100 are disconnected when not charging, the charging interface 100 will not be energized after being disconnected from the external DC power supply, thereby ensuring the safety of users using the charging interface 100.

[0169] In a low temperature environment, the battery temperature will drop to a certain extent, thus affecting the battery performance, for example, affecting the battery power supply performance and charging speed. Therefore, in order to ensure the performance of the power battery pack in a low temperature environment, in some embodiments, the battery charging and discharging device provided in the embodiment of the present invention may also have a battery preheating function, please refer to Figure 6 , Figure 6 It is a circuit schematic diagram of a battery charging and discharging device with a battery preheating function provided by an embodiment of the present invention, wherein the second end of the first bridge arm 210 is connected to the positive electrode access end, and the second end of the second bridge arm 220 is connected to the negative electrode access end.

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

[0171] A first relay K1 is connected in series to the trunk line where the neutral line of the motor M is located;

[0172] A third relay K3, 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 M and the first relay K1;

[0173] When the temperature of the power battery pack is lower than a set temperature threshold, the first relay K1 is in an off state, the third relay K3 is in an on state, and 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 to achieve heating of the power battery pack;

[0174] In the battery discharge circuit, the first bridge arm 210 is in an on state, the second bridge arm 220 is in an off state, the first battery group in the power battery pack is short-circuited by the third relay K3, and the second battery group in the power battery pack that is not short-circuited discharges to the inductor;

[0175] In the battery pre-charging circuit, the first bridge arm 210 is in a disconnected state, the second bridge arm 220 is in a conductive 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 voltage midpoint of the multiple battery packs included in the power battery pack. For example, assuming that the power battery pack includes power battery pack 1 and power battery pack 2, and the voltages of power battery pack 1 and power battery pack 2 are the same, the voltage midpoint at this time 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 voltage midpoint can ensure the battery charge and discharge balance during the subsequent battery preheating process. However, in other variant embodiments, one end of the third relay K3 can also be connected to a certain point in the power battery pack 1 or a certain point in the power battery pack 2, as long as the battery preheating can be achieved, and it does not have to be connected to the voltage midpoint.

[0177] Therefore, the battery temperature can be detected by the temperature sensor configured at the power battery pack and fed back to the controller. The controller can compare the battery temperature with the set temperature threshold according to relevant technical principles and control the on and off of the corresponding relay according to 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 an off state, the third relay K3 is in an 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 pre-charge circuit to achieve heating of the power battery pack.

[0179] In the battery discharge circuit, the first bridge arm 210 is in an on state, the second bridge arm 220 is in an off state, the first battery group (battery group 2) in the power battery pack is short-circuited by the third relay K3, and the second battery group (battery group 1) in the power battery pack that is not short-circuited discharges to the inductor.

[0180] by Figure 6 As shown in the figure as an example, the current flow of the battery discharge circuit is: the positive electrode of the battery pack 1 → the first bridge arm 210 → the inductor of the motor M → the third relay K3 → the negative electrode of the battery pack 1 → the positive electrode of the battery pack 1, thereby forming a battery discharge circuit, so 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 case, both the first relay K1 and the second bridge arm 220 are in an open state.

[0182] In the battery charging circuit, the first bridge arm 210 is in a disconnected state, the second bridge arm 220 is in a conductive state, and the first battery pack is charged by the inductor.

[0183] by Figure 6 As shown in the figure as an example, the current flow of the battery pre-charging circuit is: inductor → third relay K3 → battery pack 2 → second bridge arm 220 → inductor, thereby forming a battery charging circuit to enable the inductor to charge the power battery pack 2.

[0184] In this case, the first relay K1 , the fourth relay K4 and the first bridge arm 210 are all in an 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-charging circuit according to this strategy, the power battery pack can generate heat due to alternating discharge and charging, 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] Among them, the alternating control frequency of the battery charging circuit and the battery pre-charging circuit can also be found in the relevant records above, which will not be repeated here.

[0187] In some embodiments, in order 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 supply, the charging interface 100 can also be used to connect to an external load to power the external load.

[0188] In some embodiments, in order to improve the practicality of the battery charging and discharging device, the battery charging and discharging device provided in the embodiment of the present invention can also charge electrical equipment, wherein the electrical equipment can refer to the electrical equipment contained in the carrier using the battery charging and discharging device as the power energy, and the electrical equipment can also be called an internal load, and the internal load can be a high-voltage internal load. Based on this, the battery charging and discharging device provided in the embodiment of the present invention can also include:

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

[0190] The power-consuming device interface is used to access the power-consuming device;

[0191] The power interface is connected to the charging interface 100 or the battery pack interface 300 and is used to introduce an external DC power supply through the charging interface 100 , or to introduce a power charging and discharging device provided by the power battery pack through the battery pack interface 300 .

[0192] For the application scenario of connecting a battery charging and discharging device to a high voltage load, the embodiment of the present invention provides multiple implementation methods of connecting a battery charging and discharging device to a high voltage load. Figure 7a and Figure 7b , Figure 7a and Figure 7b The circuit schematic diagrams of a battery charging and discharging device connected to an internal load provided by an embodiment of the present invention show two different deformation modes. These two deformation modes are essentially distinguished and mainly divided into two categories:

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

[0194] The second category: internal loads draw power from the power battery pack, such as Figure 7b shown.

[0195] In the above, the internal load draws power from the power battery pack, which has 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, while there are many types of external DC power supplies, and their output voltage does not necessarily 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, thereby avoiding the burning of the internal load due to the excessive supply voltage of the internal load.

[0196] In the driving condition, that is, when the power battery pack supplies power to the electric drive assembly 200, in order to avoid that when the path between the power battery pack and the electric drive assembly 200 is turned on, a large instantaneous voltage is generated in the circuit, which may impact the motor M of the electric drive assembly 200 and thus affect the performance or life of the motor M, in some embodiments, refer to Figure 1b The electric drive assembly 200 may further include a second voltage-stabilizing capacitor C2, and two ends of the second voltage-stabilizing capacitor C2 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, through the second voltage-stabilizing capacitor C2, at the moment when the path between the power battery pack and the electric drive assembly 200 is connected, the voltage can be stabilized by the second voltage-stabilizing capacitor C2 first, and then after the voltage is stabilized, the subsequent electric drive assembly 200 is powered, thereby avoiding the impact of large instantaneous voltage on the motor M.

[0198] Based on the previous embodiment, under driving conditions, in order to prevent a large instantaneous voltage from breaking down the second voltage-stabilizing capacitor C2, in some embodiments, the battery charging and discharging device provided in the embodiments of the present invention also includes a pre-charging circuit, so that under driving conditions, the second voltage-stabilizing capacitor C2 is first charged using the pre-charging circuit, so that the terminal voltage of the second voltage-stabilizing capacitor C2 and the voltage of the power battery pack are maintained within a set voltage difference, thereby effectively preventing an instantaneous voltage from breaking down the second voltage-stabilizing capacitor C2.

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

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

[0201] A fourth relay K4 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;

[0202] A pre-charging circuit, comprising a resistor R and a fifth relay K5 connected in series; 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 the set voltage difference, the fourth relay K4 is in an off state, and the fifth relay K5 is in an on state;

[0204] When the difference between the terminal voltage of the second stabilizing capacitor C2 and the terminal voltage of the power battery pack is less than the set voltage difference, the fourth relay K4 is in the on state, and the fifth relay K5 is in the off state.

[0205] by Figure 1b For example, in this example, the relay connected to the first access terminal is the fourth relay K4, so the pre-charging circuit is connected in parallel with the fourth relay K4. Therefore, under the driving condition, the relay Kc can be controlled to be turned on first, and then the fifth relay K5 can be controlled to 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 stabilizing capacitor C2 and the relay Kc in sequence, and then flows back to the negative electrode of the power battery pack, thereby realizing the pre-charging of the second voltage stabilizing capacitor C2 and avoiding the instantaneous voltage breakdown of the second voltage stabilizing capacitor C2.

[0206] During the pre-charging of the second voltage-stabilizing capacitor C2, the terminal voltage of the second voltage-stabilizing capacitor C2 and the terminal voltage of the power battery pack can be obtained through relevant technical principles, so that when the difference between the terminal voltages of the two is less than the set voltage difference, the fifth relay K5 is controlled to be disconnected and the fourth relay K4 is controlled to be turned on, thereby realizing that after the terminal voltage of the electric drive system assembly is stabilized, the power battery pack is used to power the electric drive system assembly.

[0207] In the above, the voltage difference may be set based on experiments or experience, for example, 5V, but is not limited thereto.

[0208] Corresponding to the embodiment of the battery charging and discharging device, the embodiment of the present invention further provides a new energy vehicle, including:

[0209] the body of the vehicle; 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] In the above, the charging and discharging principle and driving principle of the new energy vehicle can be found in the description of the corresponding embodiments of the battery charging and discharging device provided by the present invention, and will not be elaborated here.

[0212] It is worth noting that the technical features or technical solutions in any of the above embodiments of the present invention can be combined or combined with each other as long as there is no contradiction in the combination or combination.

[0213] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery charging and discharging device, characterized in that: include: A charging interface, used to connect to an external DC power source, including a positive terminal and a negative terminal; An electric drive assembly, comprising a motor, a first bridge arm and a second bridge arm; each phase line of the motor is connected to the first end of the first bridge arm and the first end of the second bridge arm respectively, and the neutral line of the motor is connected to the positive electrode access terminal or the negative electrode access terminal; the second end of the first bridge arm is connected to the positive electrode access terminal, and / or the second end of the second bridge arm is connected to the negative electrode access terminal; A battery pack interface, wherein a first access end for accessing the positive electrode of the power battery pack is connected to the neutral line of the motor, and a second access end for accessing the negative electrode of the power battery pack is connected 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 turned on and off, or the second bridge arm is alternately turned on and off, so as to alternately switch the inductive energy storage circuit and the battery charging circuit; The inductive energy storage circuit is used to charge the inductance in the motor, and the inductive energy storage circuit includes the external DC power supply and the inductance; 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 device 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 time period each time it is turned on; 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 lower than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm are alternately turned on and off, or the second bridge arm is alternately turned on and off, so as 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 time period each time it is turned on; The first duration is greater than the second duration.

3. The device according to claim 1 or 2, characterized in that: The neutral line of the motor is connected to the negative electrode access terminal; the second end of the first bridge arm is connected to the positive electrode access terminal; In the inductive energy storage circuit, the first bridge arm is in an on state, and the second bridge arm is in an off state; In the battery charging circuit, the first bridge arm is in a disconnected state, and the second bridge arm is in a conductive state.

4. The device according to claim 1 or 2, characterized in that: The neutral line of the motor is connected to the positive electrode access terminal; the second end of the second bridge arm is connected to the negative electrode access terminal; In the inductive energy storage circuit, the first bridge arm is in a disconnected state, the switch tube in the second bridge arm is in a conducting state, and the diode in the second bridge arm is in a cut-off state; In the battery charging circuit, the first bridge arm is in a disconnected state, the switch tube in the second bridge arm is in a disconnected state, and the diode in the second bridge arm is in a conducting state.

5. The device 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 a disconnected state, the second bridge arm is in a conductive state, and the external DC power supply, the power battery pack and the inductor form a direct charging loop.

6. The device according to claim 1, characterized in that The second end of the first bridge arm is connected to the positive electrode access terminal, and the second end of the second bridge arm is connected to the negative electrode access terminal; The device also includes: A first relay is connected in series to a trunk line where a neutral line of the motor is located; A second relay is connected in series between the second end of the second bridge arm and the negative electrode access end; 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 disconnected state, the second relay is in the on state, and the external DC power supply and the power battery pack form a direct charging circuit.

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

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

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

10. The device according to claim 1, characterized in that The second end of the first bridge arm is connected to the positive electrode access terminal, and the second end of the second bridge arm is connected to the negative electrode access terminal; The device also includes: A first relay is connected in series to a trunk line where a neutral line of the motor is located; a third relay, one end of which is connected between the plurality of 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 off state, the third relay is in an on 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 to achieve heating of the power battery pack; In the battery discharge circuit, the first bridge arm is in an on state, the second bridge arm is in an off state, the first battery group in the power battery pack is short-circuited by the third relay, and the second battery group in the power battery pack that is not short-circuited discharges to the inductor; In the battery pre-charging circuit, the first bridge arm is in a disconnected state, the second bridge arm is in a conductive state, and the first battery pack is charged by the inductor.

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

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

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

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