CN213007662U

CN213007662U - Charging and discharging device and electric vehicle

Info

Publication number: CN213007662U
Application number: CN202021242692.8U
Authority: CN
Inventors: 孙嘉品; 王超; 刘伟冬
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2021-04-20
Anticipated expiration: 2030-06-30

Abstract

The utility model provides a charge and discharge device and electric vehicle, charge and discharge device include power factor correction module, transformer and rectification contravariant module, and the transformer includes first winding, second winding and third winding, first winding and second winding series connection, and power factor correction module includes: the first ends of the first and second bidirectional switch units are respectively connected with the first end and the second end of the first winding and the second winding after being connected in series, the second ends of the first and second bidirectional switch units are connected with the first end of the inductance unit, the second end of the inductance unit is connected with the first end of an external charging port, the middle point of the first winding and the second winding in series is connected with the second end of the charging port, and the rectification inverter module is connected with the third winding. The utility model discloses simplified circuit structure and reduced the quantity of components and parts, the electric energy of circuit consume reduces, has greatly reduced the circuit cost, has improved charge efficiency, and power factor correction module's current direction is controllable, and the reliability of circuit is high.

Description

Charging and discharging device and electric vehicle

Technical Field

The utility model relates to a vehicle technical field especially relates to a charge and discharge device and electric vehicle.

Background

Currently, with the commercialization progress of electric vehicles, an on-board charger for converting ac power of a power grid into dc power to charge a power battery in the electric vehicle has become an important structure of the electric vehicle.

In the related art, the vehicle-mounted charger comprises an alternating current loop and a high-voltage direct current loop, wherein the alternating current loop comprises a power factor correction circuit formed by six MOS (metal oxide semiconductor) tubes, the body diodes of the six MOS tubes are conducted in the same direction, and the high-voltage direct current loop comprises a first transformer, a rectification topology corresponding to a primary coil of the first transformer and a rectification topology corresponding to a secondary coil of the first transformer.

However, the vehicle-mounted charger in the related art has the following drawbacks: the current direction of each MOS tube in the power factor correction circuit is uncontrollable, namely the current direction of the power factor correction circuit is uncontrollable, and the reliability of the circuit is poor; in addition, the high-voltage direct-current circuit needs two rectification topologies, so that the high-voltage direct-current circuit is complex in structure and multiple in components, and the vehicle-mounted charger is high in cost and low in charging efficiency.

SUMMERY OF THE UTILITY MODEL

In view of the above problem, an object of the embodiments of the present invention is to provide a charging and discharging device and an electric vehicle to solve the problems of poor reliability, high cost and low charging efficiency of the vehicle-mounted charger in the related art.

In order to solve the above problem, the embodiment of the utility model discloses a charge and discharge device, include: the power factor correction module comprises a first winding, a second winding and a third winding, wherein the first winding and the second winding are connected in series, the power factor correction module comprises a first bidirectional switch unit, a second bidirectional switch unit and an inductance unit, a first end of the first bidirectional switch unit is connected with a first end of the first winding and the second winding after being connected in series, a first end of the second bidirectional switch unit is connected with a second end of the first winding and the second winding after being connected in series, a second end of the first bidirectional switch unit and a second end of the second bidirectional switch unit are connected with a first end of the inductance unit, a second end of the inductance unit is connected with a first end of an external charging port, and a midpoint of the first winding and the second winding after being connected in series is connected with a second end of the external charging port, and the rectification inversion module is connected with the third winding.

In order to solve the problem, the embodiment of the utility model provides a still disclose an electric vehicle, include charge and discharge device.

The embodiment of the utility model provides a include following advantage: compared with the vehicle-mounted charger in the related technology, the transformer is arranged between the power factor correction module and the rectification inversion module, and the rectification topology corresponding to the primary coil of the transformer can be at least reduced, so that the circuit structure is effectively simplified, the number of components is reduced, the electric energy consumed by the circuit is reduced, the circuit cost is greatly reduced, and the charging efficiency is improved; in addition, the power factor correction module comprises the first bidirectional switch unit and the second bidirectional switch unit, so that the current direction of the power factor correction module is controllable while the power factor correction module realizes the power factor correction function, and the high reliability of the circuit is ensured.

Drawings

Fig. 1 is a block diagram of a charging and discharging device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an embodiment of a charging and discharging device according to the present invention;

fig. 3 is a schematic structural view of another embodiment of the charging and discharging device of the present invention;

fig. 4 is a schematic structural diagram of a rectifier module in another embodiment of the charging and discharging device of the present invention.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.

Referring to fig. 1, a block diagram of an embodiment of a charging and discharging device 10 according to the present invention is shown, and specifically includes the following modules: the power factor correction module 1, the transformer 2 and the rectification inversion module 3 are used for charging or discharging the power battery, the transformer 2 comprises a first winding, a second winding and a third winding, the first winding and the second winding are connected in series, the power factor correction module 1 comprises a first bidirectional switch unit 11, a second bidirectional switch unit 12 and an inductance unit 13, a first end of the first bidirectional switch unit 11 is connected with a first end of the first winding and the second winding after being connected in series, a first end of the second bidirectional switch unit 12 is connected with a second end of the first winding and the second winding after being connected in series, a second end of the first bidirectional switch unit 11 and a second end of the second bidirectional switch unit 12 are connected with a first end of the inductance unit 13, a second end of the inductance unit 13 is connected with a first end of the external charging port 20, a middle point of the first winding and the second winding after being connected in series is connected with a second end of the external charging port 20, and the rectification inversion module 3 is connected with the third winding.

Specifically, the bidirectional switch unit (the first bidirectional switch unit 11 or the second bidirectional switch unit 12) has three states, namely, an off state, a first on state in which the bidirectional switch unit is turned on in a first on direction allowing the same direction of current to flow as the first on direction, and a second on state in which the bidirectional switch unit is turned on in a second on direction allowing the same direction of current to flow as the second on direction, wherein the first on direction is opposite to the second on direction. Like this, only need control the conducting state of first bilateral switch unit 11 and second bilateral switch unit 12, just can realize controlling the current direction that first bilateral switch unit 11 and second bilateral switch unit 12 allow to flow through, make power factor correction module 1's current direction controllable, ensure the utility model discloses the reliability of charge-discharge device 10 of embodiment.

Specifically, the inductance unit 13 is configured to store electric energy or release the stored electric energy during the operation of the power factor correction module 1, so as to raise the voltage of the charging loop of the power factor correction module 1 during the process of inputting the electric energy of the power grid into the external charging port 20 and charging the power battery through the charging and discharging device 10, thereby implementing high-voltage transmission of the electric energy, facilitating improvement of the charging efficiency of the charging and discharging device 10 and shortening of the charging time, and in the process of outputting the electric energy to the power grid or the load from the power battery through the external charging port 20, lowering the voltage of the discharging loop of the power factor correction module 1, thereby implementing matching of the output voltage of the discharging loop with the voltage of the power grid or with the voltage required by the load.

Specifically, the transformer 2 is arranged between the power factor correction module 1 and the rectification inversion module 3, and compared with a vehicle-mounted charger in the related art, the rectifier topology corresponding to the primary coil of the transformer can be at least reduced, the circuit structure is effectively simplified, the number of components is reduced, the electric energy consumed by the circuit is reduced, the circuit cost is greatly reduced, and the charging efficiency is improved; in addition, since the power factor correction module 1 includes the first bidirectional switch unit 11 and the second bidirectional switch unit 12, the power factor correction module 1 can control the current direction of the power factor correction module 1 while implementing the power factor correction function, thereby ensuring high reliability of the circuit.

Optionally, as shown in fig. 2, the charging and discharging device 10 according to the embodiment of the present invention may further include a rectifier module 4 for charging the battery 40, the transformer 2 may further include a fourth winding, and the rectifier module 4 is connected to the fourth winding. Since the vehicle-mounted dc converter is disposed in the low-voltage dc loop of the charging circuit when the functions of the vehicle-mounted dc converter and the vehicle-mounted charger are integrated in one charging circuit in the related art, the low-voltage dc loop includes the second transformer, the rectifying topology corresponding to the primary coil of the second transformer, and the rectifying topology corresponding to the secondary coil of the second transformer, whereas the embodiment of the present invention can realize the integration of the functions of the vehicle-mounted dc converter and the vehicle-mounted charger in one circuit only by one transformer 2 (i.e., the power factor correction module 1, the rectifying/inverting module 3 for charging or discharging the power battery 30, and the rectifying module 4 for charging the storage battery 40 are integrated in one circuit), and since the transformer 2 is disposed between the power factor correction module 1 and the rectifying module 4, the rectifying module 4 only needs one rectifying topology, the structure of the rectifier module 4 is simpler, the number of required components is less, namely, the consumed electric energy is reduced, the charging efficiency is improved, and the cost is reduced. As shown in fig. 2, the first winding, the second winding, and the fourth winding may be disposed on the same side.

In fig. 2, the pfc module 1 may be configured to perform pfc and voltage boost on a voltage and a current corresponding to a grid ac signal input from the external charging port 20 to generate a first ac signal, and transmit the first ac signal to the first winding or the second winding. And then the first winding or the second winding transmits the first alternating current signal to the fourth winding or the third winding. The pfc module 1 may be further configured to perform pfc on the first ac signal input by the first winding or the second winding to generate a grid ac signal, and output the grid ac signal to a grid or an ac load through the external charging port 20 to supply power to the grid or supply power to the ac load.

In fig. 2, the rectification and inversion module 3 may be configured to rectify the first ac signal transmitted by the third winding into a dc signal and output the dc signal to the power battery 30 to charge the power battery 30, and the rectification and inversion module 3 may be configured to invert the dc signal output by the power battery 30 into a first ac signal and transmit the first ac signal to the third winding. And the third winding transmits the first alternating current signal to the first winding or the second winding or the fourth winding so as to discharge the power battery 30.

In fig. 2, the rectifying module 4 is configured to rectify the first ac signal input by the fourth winding into a dc signal to charge the battery 40.

Therefore, in the charging and discharging device 10 of fig. 2, the power factor correction module 1-the first winding or the second winding-the third winding-the rectification inverter module 3 may form a first electric loop for charging the power battery 30, the power factor correction module 1-the first winding or the second winding-the fourth winding-the rectification module 4 may form a second electric loop for charging the storage battery 40, the rectification inverter module 3-the third winding-the first winding or the second winding-the power factor correction module 1 may form a third electric loop for supplying power to the grid or the ac load, and the rectification inverter module 3-the third winding-the fourth winding-the rectification module 4 may form a fourth electric loop for charging the storage battery 40.

Alternatively, as shown in fig. 2, the first bidirectional switch unit 11 may include a first bidirectional switch device, or, as shown in fig. 3, the first bidirectional switch unit 11 may include a first switch tube having a body diode and a second switch tube having a body diode, the first switch tube and the second switch tube being connected in series, and a conduction direction of the body diode of the first switch tube and a conduction direction of the body diode of the second switch tube being opposite. In this way, the first bidirectional switch unit 11 only needs to be composed of the first bidirectional switch device or only needs to be composed of the first switch tube and the second switch tube, the structure of the first bidirectional switch unit 11 is simple and the required components are few, the power consumption of the first bidirectional switch unit 11 is low, and the cost of the first bidirectional switch unit 11 is low. Alternatively, as shown in fig. 3, the first switching tube may be a first MOS transistor Q1, and the second switching tube may be a second MOS transistor Q2.

Alternatively, as shown in fig. 2, the second bidirectional switch unit 12 may include a second bidirectional switch device, or, as shown in fig. 3, the second bidirectional switch unit 12 may include a third switch tube having a body diode and a fourth switch tube having a body diode, the third switch tube and the fourth switch tube being connected in series, and a conduction direction of the body diode of the third switch tube and a conduction direction of the body diode of the fourth switch tube being opposite. In this way, the second bidirectional switch unit 12 only needs to be composed of the second bidirectional switch device or only needs to be composed of the third switch tube and the fourth switch tube, the structure of the second bidirectional switch unit 12 is simple, the required components are few, the power consumed by the second bidirectional switch unit 12 is low, and the cost of the second bidirectional switch unit 12 is low. Alternatively, as shown in fig. 3, the third switching tube may be a third MOS transistor Q3, and the fourth switching tube may be a fourth MOS transistor Q4.

In the embodiment of the present invention, the first bidirectional switch unit 11 only needs to be composed of the first bidirectional switch device, or only needs to be composed of the first switch tube and the second switch tube; the second bidirectional switch unit 12 only needs to be composed of the second bidirectional switch device, or only needs to be composed of the third switch tube and the fourth switch tube, so that the structure of the power factor correction module 1 is simpler than that of a power factor correction circuit of an on-board charger in the related art, fewer components are needed, the power consumed by the power factor correction module 1 is low, and the cost of the power factor correction module 1 is low.

Optionally, the charging and discharging device 10 of the embodiment of the present invention may further include: the controller is used for controlling the first bidirectional switch unit 11 and the second bidirectional switch unit 12 to work at a first frequency, and the controller is respectively connected with the control ends of the first bidirectional switch unit 11 and the second bidirectional switch unit 12; the first frequency is greater than the frequency of the mains ac signal input or output by the external charging port 20. Like this, can improve the frequency to first frequency of the first alternating current signal that power factor correction module 1 generated, be favorable to improving the utility model discloses the charge efficiency of charge-discharge device 10 shortens the charge time.

Alternatively, the controller may determine duty ratios corresponding to the first bidirectional switch unit 11 and the second bidirectional switch unit 12 according to the real-time grid voltage, the real-time grid current, the voltage of the real-time power battery 30, and the first frequency corresponding to the first bidirectional switch unit 11 and the second bidirectional switch unit 12, and control the first bidirectional switch unit 11 and the second bidirectional switch unit 12 to operate according to the duty ratios, so as to control the first bidirectional switch unit 11 and the second bidirectional switch unit 12 to operate at the first frequency.

Alternatively, as shown in fig. 2 and 3, the rectification inverter module 3 may include four fifth switching tubes and a first capacitor unit for connecting with the power battery 30, where the four fifth switching tubes form a first full-bridge topology, the first full-bridge topology is connected in parallel with the first capacitor unit, and the first full-bridge topology is connected with the third winding. The first capacitor unit is configured to filter a first ac signal output by the first full-bridge topology, and filter a dc signal output by the power battery 30. Alternatively, as shown in fig. 2 and 3, the four fifth switching transistors may be a MOS transistor Q5, a MOS transistor Q6, a MOS transistor Q7, and a MOS transistor Q8, and the first capacitor unit may be a first capacitor C1.

Alternatively, as shown in fig. 2 and 3, the rectifying module 4 may include a rectifying unit 41 and a second capacitor unit for connecting with the battery 40, the rectifying unit 41 being connected in parallel with the second capacitor unit, the rectifying unit 41 being connected with the fourth winding. The second capacitor unit is used for filtering the dc signal output by the rectifying unit 41. Alternatively, as shown in fig. 2 and 3, the second capacitance unit may be a second capacitance C2.

Alternatively, as shown in fig. 2 and 3, the rectifying unit 41 may include four sixth switching tubes, and the four sixth switching tubes form a second full-bridge topology, or, as shown in fig. 4, the number of the fourth windings may be two, and two fourth windings are connected in series, and the rectifying module 4 may include a seventh switching tube and an eighth switching tube, the seventh switching tube is connected to one of the fourth windings and the second capacitor unit, the eighth switching tube is connected to the other of the fourth windings and the second capacitor unit, and the seventh switching tube and the eighth switching tube form a full-wave rectifying topology. That is, the rectifying unit 41 may rectify the first ac signal input from the fourth winding into a dc signal through the second full-bridge topology or the full-wave rectification topology to charge the battery 40. Alternatively, as shown in fig. 2 and 3, the four sixth switching transistors may be a MOS transistor Q9, a MOS transistor Q10, a MOS transistor Q11, and a MOS transistor Q12. Alternatively, as shown in fig. 4, the seventh switch tube may be a MOS transistor Q13, and the eighth switch tube may be a MOS transistor Q14.

Optionally, as shown in fig. 2 and 3, the power factor correction module 1 may further include a third capacitive unit for connecting to the power grid, a first end of the third capacitive unit being connected to the second end of the inductive unit 13, and a second end of the third capacitive unit being connected to a midpoint of the series connection of the first winding and the second winding. Specifically, the third capacitance unit is used for filtering the grid ac signal input by the charging port 20 and the grid ac signal output through the charging port 20. Alternatively, as shown in fig. 2 and 3, the third capacitance unit may be a third capacitance C3.

The operation of the charging and discharging device 10 in fig. 3 is briefly described as follows:

when the power battery 30 is charged by the power grid through the charging and discharging device 10, if the voltage of the power grid is a positive voltage, in the first stage, the controller controls the conduction of the MOS transistor Q2 and the MOS transistor Q4, the MOS transistor Q1 and the MOS transistor Q3 are turned off, at the moment, the inductor L1 stores energy, the energy stored in the inductor L1 cannot be transmitted to the high-voltage side of the transformer 2, and the current flowing through the inductor L1 is increased; in the second stage, the controller controls the MOS transistor Q1, the MOS transistor Q3 and the MOS transistor Q4 to be turned off, the MOS transistor Q2 is continuously turned on, and at this time, the inductor L1 releases the stored energy, transmits the energy to the transformer 2, and then transmits the energy to the power battery 30; in the third stage, the controller controls the MOS transistor Q1 and the MOS transistor Q3 to be turned off, the MOS transistor Q2 and the MOS transistor Q4 are turned on, the energy stored in the inductor L1 is released, the energy is stored in the inductor L1 again, the energy stored in the inductor L1 is not transferred to the high-voltage side of the transformer 2, and the current flowing through the inductor L1 is increased; in the fourth stage, the controller controls the MOS transistor Q4 to be turned on, and the MOS transistor Q1, the MOS transistor Q2 and the MOS transistor Q3 are turned off, so that the inductor L1 releases energy, and the energy is transmitted to the transformer 2 and then the power battery 30. It should be noted that, when the grid voltage is a negative voltage, the process of charging the power battery 30 by the power grid through the charging and discharging device 10 is similar to the process of charging the power battery 30 by the power grid through the charging and discharging device 10 when the grid voltage is a positive voltage, and repeated description is not repeated below.

When the charging and discharging device 10 discharges the power battery 30, in a fifth stage, the MOS transistor Q5 and the MOS transistor Q8 are connected, the rectification inverter module 3 inverts high-voltage direct current output by the power battery 30 into high-frequency alternating current, then energy is transmitted to the first winding or the second winding of the transformer 2, the controller controls the connection of the MOS transistor Q2, the MOS transistor Q1, the MOS transistor Q3 and the MOS transistor Q4 are disconnected, current of the inductor L1 is increased, and the energy is transmitted to a power grid; in the sixth stage, the controller controls the MOS transistor Q5 and the MOS transistor Q8 to be turned off, the controller controls the MOS transistor Q2 and the MOS transistor Q4 to be turned on, and controls the MOS transistor Q1 and the MOS transistor Q3 to be turned off, the inductor L1 releases electric energy, the current of the inductor L1 is reduced, the inductor L1 continues to charge the third capacitor C3, that is, the inductor L1 discharges the power grid; in the seventh stage, the MOS transistor Q6 and the MOS transistor Q7 are switched on, the MOS transistor Q5 and the MOS transistor Q8 are switched off, then the controller controls the MOS transistor Q1, the MOS transistor Q2 and the MOS transistor Q3 to be switched off, the MOS transistor Q4 is switched on, and the current of the inductor L1 is increased; in the eighth stage, the controller controls the MOS transistor Q6 and the MOS transistor Q7 to be turned off, the controller controls the MOS transistor Q2 and the MOS transistor Q4 to be turned on, and controls the MOS transistor Q1 and the MOS transistor Q3 to be turned off, the inductor L1 releases electric energy, the current of the inductor L1 decreases, and the inductor L1 continues to charge the third capacitor C3, that is, the power grid is discharged.

The operation process of the charging and discharging device 10 for charging the storage battery 40 is similar to the operation process of the charging and discharging device 10 for charging the power battery 30, and will not be described in detail below.

The utility model discloses charge-discharge device includes following advantage: the functions of the vehicle-mounted direct current converter and the vehicle-mounted charger can be integrated in one circuit only through one transformer, the rectifying module is connected with the fourth winding, and the rectifying inversion module is connected with the third winding; in addition, the power factor correction module comprises the first bidirectional switch unit and the second bidirectional switch unit, so that the current direction of the power factor correction module is controllable while the power factor correction module realizes the function of power factor correction, and the high reliability of a circuit is ensured; in addition, the first bidirectional switch unit and the second bidirectional switch unit are controlled by the controller to work at the first frequency, so that the charging efficiency is improved, and the charging time is shortened.

The embodiment of the utility model provides a still disclose an electric vehicle, including foretell charge-discharge device 10.

Specifically, the utility model discloses electric vehicle includes power battery 30 and battery 40, and the rectification contravariant module is connected with power battery 30 among the charging and discharging device 10, and the rectification module is connected with battery 40 among the charging and discharging device 10.

The utility model discloses electric vehicle includes following advantage: the charging and discharging device can integrate the functions of the vehicle-mounted direct current converter and the vehicle-mounted charger into a circuit only through one transformer, the rectifying module is connected with the fourth winding, and the rectifying inversion module is connected with the third winding; in addition, because the power factor correction module in the charge and discharge device comprises the first bidirectional switch unit and the second bidirectional switch unit, the current direction of the power factor correction module is controllable while the power factor correction module realizes the function of power factor correction, and the high reliability of the circuit is ensured; in addition, the charging and discharging device controls the first bidirectional switch unit and the second bidirectional switch unit to work at the first frequency through the controller, and charging efficiency is improved, and charging time is shortened. For the embodiment of the electric vehicle, since the charging and discharging device is included, the description is relatively simple, and relevant points can be referred to the partial description of the embodiment of the charging and discharging device.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

While alternative embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including alternative embodiments and all such alterations and modifications as fall within the true scope of the embodiments of the invention.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The above detailed description is given to a charging and discharging device and an electric vehicle provided by the present invention, and the specific examples are applied herein to explain the principle and the implementation of the present invention, and the description of the above embodiments is only used to help understanding the present invention; meanwhile, for the person skilled in the art, according to the present invention, there may be variations in the specific embodiments and the application range, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A charging and discharging device, comprising: the power factor correction module comprises a first winding, a second winding and a third winding, wherein the first winding and the second winding are connected in series, the power factor correction module comprises a first bidirectional switch unit, a second bidirectional switch unit and an inductance unit, a first end of the first bidirectional switch unit is connected with a first end of the first winding and the second winding after being connected in series, a first end of the second bidirectional switch unit is connected with a second end of the first winding and the second winding after being connected in series, a second end of the first bidirectional switch unit and a second end of the second bidirectional switch unit are connected with a first end of the inductance unit, a second end of the inductance unit is connected with a first end of an external charging port, and a midpoint of the first winding and the second winding after being connected in series is connected with a second end of the external charging port, and the rectification inversion module is connected with the third winding.

2. The charging and discharging device according to claim 1, further comprising a rectifying module for charging the battery, wherein the transformer further comprises a fourth winding, and wherein the rectifying module is connected to the fourth winding.

3. The charging and discharging device according to claim 1,

the first bidirectional switching unit includes a first bidirectional switching device, or,

the first bidirectional switch unit comprises a first switch tube with a body diode and a second switch tube with a body diode, the first switch tube and the second switch tube are connected in series, and the conduction direction of the body diode of the first switch tube is opposite to the conduction direction of the body diode of the second switch tube.

4. The charging and discharging device according to claim 1,

the second bidirectional switch cell includes a second bidirectional switch device, or,

the second bidirectional switch unit comprises a third switch tube with a body diode and a fourth switch tube with a body diode, the third switch tube and the fourth switch tube are connected in series, and the conduction direction of the body diode of the third switch tube is opposite to that of the body diode of the fourth switch tube.

5. The charging and discharging device according to claim 1, further comprising:

the controller is used for controlling the first bidirectional switch unit and the second bidirectional switch unit to work at a first frequency and is respectively connected with the control ends of the first bidirectional switch unit and the second bidirectional switch unit; the first frequency is greater than the frequency of an alternating current signal input or output by the external charging port.

6. The charging and discharging device according to claim 1, wherein the rectifying and inverting module comprises four fifth switching tubes and a first capacitor unit connected to the power battery, the four fifth switching tubes form a first full-bridge topology, the first full-bridge topology is connected in parallel to the first capacitor unit, and the first full-bridge topology is connected to the third winding.

7. The charging and discharging device according to claim 2, wherein the rectifying module comprises a rectifying unit and a second capacitor unit for connecting with the storage battery, the rectifying unit is connected in parallel with the second capacitor unit, and the rectifying unit is connected with the fourth winding.

8. Charging and discharging device according to claim 7,

the rectifying unit comprises four sixth switching tubes, and the four sixth switching tubes form a second full-bridge topology, or,

the number of the fourth windings is two, the two fourth windings are connected in series, the rectifying module comprises a seventh switching tube and an eighth switching tube, the seventh switching tube is connected with one of the fourth windings and the second capacitor unit, the eighth switching tube is connected with the other fourth winding and the second capacitor unit, and the seventh switching tube and the eighth switching tube form a full-wave rectifying topology.

9. The charging and discharging device according to claim 1, wherein the power factor correction module further comprises a third capacitor unit, a first end of the third capacitor unit is connected to the second end of the inductor unit, and a second end of the third capacitor unit is connected to a midpoint of the series connection of the first winding and the second winding.

10. An electric vehicle characterized by comprising the charge and discharge device according to any one of claims 1 to 9.