Charging and discharging device and power transmission method thereof

Abstract

The invention discloses a charging and discharging device and a power transmission method thereof, and relates to the field of battery power. The charging and discharging device comprises a communication module which is in communication connection with a BMS and is used for performing first communication with the BMS based on a general charging protocol under the condition that the charging and discharging device is in a first energy transmission mode and the BMS does not support a specific discharging protocol; one side of the conversion module is connected with the battery, the other side of the conversion module is connected with the alternating current side connecting structure, and the conversion module is used for converting the direct current provided by the battery into alternating current in the first communication process and transmitting the alternating current to the alternating current side connecting structure; wherein the first energy transmission mode is a mode in which the battery transmits power to the AC side connection structure of the device. According to the embodiment of the invention, the battery can be discharged under the condition that the BMS does not support a discharge protocol.

Description

[0001] This divisional application is filed based on the application with the application number "202011425796.7", applicant "Contemporary Amperex Technology Co., Ltd.", filing date "December 8, 2020", and invention title "Charge and Discharge Device and Its Power Transmission Method". Technical Field

[0002] This application relates to the field of battery power, and particularly to a charge and discharge device and its power transmission method. Background Art

[0003] With the development of new energy, more and more fields use new energy as power. Due to advantages such as high energy density, rechargeability, safety, and environmental friendliness, batteries are widely used in power devices such as electric vehicles, electric ships, and spacecraft.

[0004] When using a battery for charging and discharging, it is necessary to manage and control the battery through a Battery Management System (BMS).

[0005] However, the vast majority of BMSs on the market do not support the discharge protocol. When the BMS does not support the discharge protocol, the battery cannot be discharged. Summary of the Invention

[0006] The charge and discharge device and its power transmission method provided by the embodiments of this application can achieve the discharge of the battery when the BMS does not support the discharge protocol.

[0007] In a first aspect, an embodiment of this application provides a charge and discharge device, including:

[0008] A communication module, communicatively connected to a Battery Management System (BMS), for performing a first communication with the BMS based on a general charging protocol when in a first energy transmission mode and the BMS does not support a specific discharge protocol;

[0009] A conversion module, with one side connected to the battery and the other side connected to an AC side connection structure, for converting the direct current provided by the battery into alternating current and transmitting the alternating current to the AC side connection structure during the first communication;

[0010] Wherein, the first energy transmission mode is a mode in which the battery transmits power to the AC side connection structure of the device.

[0011] In a second aspect, an embodiment of this application provides a power transmission method for a charge and discharge device, including:

[0012] When in the first energy transmission mode and the battery management system (BMS) does not support a specific discharge protocol, perform the first communication with the BMS based on the general charging protocol.

[0013] During the first communication, convert the direct current provided by the battery into alternating current and transmit the alternating current to the AC-side connection structure.

[0014] Among them, the first energy transmission mode is the mode in which the battery transmits power to the AC-side connection structure of the device.

[0015] According to the charging and discharging device and its power transmission method in the embodiments of the present application, when the battery transmits power to the AC-side connection structure, when the BMS does not support a specific discharge protocol, the general charging protocol can be selected to implement the communication between the BMS and the charging and discharging device, so as to realize the discharge of the battery when the BMS does not support the discharge protocol. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0017] Figure 1 is a schematic structural diagram of a charging and discharging device provided by an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of the power mode of the conversion module provided by an embodiment of the present application;

[0019] Figure 3 is a schematic structural diagram of an exemplary charging and discharging device provided by an embodiment of the present application;

[0020] Figure 4 is a schematic flowchart of a power transmission method of a charging and discharging device provided by an embodiment of the present application;

[0021] Figure 5 is a schematic flowchart of another power transmission method of a charging and discharging device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the objectives, technical solutions, and advantages of the present application more clear, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0023] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0024] At the present stage, with the development of battery technology, the usage scenarios of batteries have become increasingly rich. For example, taking the battery installed in an electric vehicle as an example, the usage scenario of the battery installed in an electric vehicle can be called the vehicle-to-everything (V2X) scenario. Specifically, the V2X scenario can include the grid-to-vehicle (G2V) scenario, the vehicle-to-grid (V2G) scenario, the vehicle-to-load (V2L) scenario, etc.

[0025] However, in battery discharge scenarios such as V2L or V2G, since most of the existing BMSs do not support the discharge protocol, the discharge of the battery cannot be achieved.

[0026] Based on this, the embodiments of the present application provide a charging and discharging device and its power transmission method, which can be applied to scenarios of discharging a battery. For example, it can be applied to specific scenarios where the battery powers an AC load. Another example is that it can be applied to specific scenarios where the battery discharges reversely towards the AC power grid. In the embodiments of the present application, when the BMS does not support a specific discharge protocol, the general charging protocol can be used to realize the communication between the BMS and the charging and discharging device. Therefore, even if the BMS does not support a specific discharge protocol, the discharge of the battery can still be realized. In some embodiments, the charging and discharging device can be in the form of a pile type, wall-mounted type or portable type, etc., and its specific type is not limited.

[0027] First, for a better understanding of the present application, the embodiments of the present application specifically explain concepts such as batteries, BMS, the first energy transmission mode, and the second energy transmission mode.

[0028] (1) Battery. The battery in the embodiments of the present application can be a lithium-ion battery, lithium metal battery, lead-acid battery, nickel-cadmium battery, nickel-metal hydride battery, lithium-sulfur battery, lithium-air battery or sodium-ion battery, etc., which is not limited here. In terms of scale, the battery in the embodiments of the present application can be a single cell, or a battery module or battery pack, which is not limited here. In terms of application scenarios, the battery can be applied in power devices such as automobiles and ships. For example, it can be applied in an electric vehicle to supply power to the motor of the electric vehicle and serve as the power source of the electric vehicle.

[0029] (2) BMS. It has the functions of collecting / calculating battery parameters and managing each functional module in the battery device and the battery. Exemplarily, it can control the energy transmission direction of the charging and discharging device, can judge whether the capacity parameter of the battery is greater than a preset threshold, can calculate the SOC, and can control the on / off of the relay, etc.

[0030] (3) The first energy transmission mode, which is a mode in which the battery transmits power to the AC-side connection structure of the charging and discharging device, that is, a mode in which the battery discharges towards the AC-side connection structure.

[0031] In some embodiments, the first energy transmission mode can be further divided into different sub-modes according to the specific type of the AC-side connection structure.

[0032] Among them, the AC-side connection structure can be an AC-side power supply or an AC-side load.

[0033] Correspondingly, the first energy transmission mode can include:

[0034] The first sub - mode represents the mode in which the battery transmits power to the AC - side power source. Exemplarily, if the battery is the power battery in an electric vehicle and the AC - side power source is the power grid, the first sub - mode can be called the V2G energy transfer mode, which can be abbreviated as V2G for short. In the V2G mode, the electric vehicle can discharge power reversely towards the power grid through the charging and discharging device. For example, when the electric vehicle is not in operation, it can be connected to the power grid through the charging and discharging device and the AC charging pile, and sell the idle electric energy of the battery to the power grid. In the G2V mode, the power grid can charge the electric vehicle through the charging and discharging device.

[0035] The second sub - mode represents the mode in which the battery transmits power to the AC - side load. Exemplarily, if the battery is the power battery in an electric vehicle, the second sub - mode can be called the V2L energy transfer mode, which can be abbreviated as V2L for short.

[0036] (4) The second energy transfer mode is the mode in which the AC - side power source transmits power to the battery. Exemplarily, if the battery is the power battery in an electric vehicle and the AC - side power source is the power grid, the second energy transfer mode can be called the G2V energy transfer mode, which can be abbreviated as G2V for short. In the G2V mode, the power grid can charge the electric vehicle through the charging and discharging device. For example, the electric vehicle can be connected to the power grid through the charging and discharging device and the AC charging pile, and use the power grid to charge the battery.

[0037] After fully understanding the above concepts, the following parts of the embodiments of the present application will sequentially describe the charging and discharging device and the power transmission method of the charging and discharging device.

[0038] Figure 1 is a schematic structural diagram of a charging and discharging device provided by an embodiment of the present application. As Figure 1 shown, the charging and discharging device 10 includes a communication module 11 and a conversion module 12.

[0039] For communication module 11.

[0040] In terms of the connection relationship, the communication module 11 is communicatively connected to the BMS 20. In some embodiments, Controller Area Network (CAN) communication can be performed between the communication module 11 and the BMS 20, and the communication method therebetween is not limited.

[0041] Functionally, the communication module 11 is used to perform a first communication with the BMS 20 based on a general charging protocol when in the first energy transfer mode and the BMS 20 does not support a specific discharge protocol.

[0042] First, for a general charging protocol, it can refer to a charging protocol that is commonly used within a certain range between an electric vehicle charger and a battery management system. Exemplarily, it can be a national standard charging protocol. For example, the GB / T 27930-2015 protocol (i.e., the communication protocol between an off-vehicle conductive charger for electric vehicles and a battery management system implemented since January 1, 2016). It should be noted that the general charging protocol can also be other versions of the protocol, and no limitation is made in this regard.

[0043] In some embodiments, the general charging protocol is obtained by expanding an existing general protocol.

[0044] In one embodiment, during the process of discharging between a charging and discharging device and a BMS based on the general charging protocol, in the charging parameter configuration stage, the communication module 11 can notify the BMS 20 of the maximum input capacity on the AC side through a CML message (i.e., a message for notifying the BMS 20 about the maximum output capacity of the charger). Also, the BMS 20 notifies the communication module 11 of the battery discharge parameters through a BCP message (i.e., a message for notifying the charger about the charging parameters of the power battery).

[0045] In one embodiment, during the charging stage, the BMS 20 can notify the communication module 11 of the battery discharge demand through a BLC message (i.e., a message for notifying the charger about the battery charging demand). The BMS 20 can also notify the communication module 11 of the total battery charging status through a BCS message (i.e., a message for notifying the charger about the total battery charging status). Also, the BMS 20 can notify the communication module 11 to abort the discharge of the BMS 20 through a BST message (i.e., a message for notifying the BMS to abort charging). Also, the communication module 11 can notify the BMS 20 to abort the discharge of the communication module 11 through a CST message (i.e., a message for notifying the charger to abort charging).

[0046] Second, for a specific discharge protocol, it can refer to a discharge protocol formulated for the discharge process between a charger and a BMS. Specifically, the specific discharge protocol can stipulate the physical layer, the version of the communication network, the frame format, the protocol data unit format, the network address, and the messages in stages such as the handshake stage and the discharge stage to be applicable to the discharge scenario.

[0047] Next, in some embodiments, the communication module 11 may first communicate with the BMS 20 based on a general charging protocol, and then, during the handshake phase, determine whether the BMS 20 supports a specific discharge protocol. Specifically, the communication module 11 may determine the protocol version used by the BMS 20 based on the received vehicle handshake message (such as the BHM message in the GB / T 27930-2015 protocol). If the protocol version it uses does not include the specific discharge protocol, it is determined that the BMS 20 does not support the specific discharge protocol.

[0048] In some embodiments, the communication module 11 is further configured to:

[0049] When in the first energy transfer mode and the BMS 20 supports the specific discharge protocol, perform a first communication with the BMS 20 based on the specific discharge protocol.

[0050] It should be noted that the first communication in this application is used to distinguish from the second communication mentioned in the subsequent content. Among them, the first communication represents the communication during the battery discharge process, and the second communication represents the communication during the battery charging process. Specifically, if the BMS 20 does not support the specific discharge protocol, the first communication may be a communication implemented based on the general charging protocol communication. If the BMS 20 supports the specific discharge protocol, the first communication may be a communication implemented based on the specific discharge protocol communication.

[0051] In some embodiments, the communication module 11 is further configured to:

[0052] When in the second energy transfer mode, perform a second communication with the BMS based on the general charging protocol. It should be noted that the relevant description of the second communication can refer to the relevant description of the previous embodiment and will not be elaborated here.

[0053] In some embodiments, the communication module 11 is further configured to receive an instruction sent by the user to enter the energy transfer mode. Among them, the user can select the energy transfer mode and corresponding parameters through a mobile application or the operation panel of an electronic device, and then generate an instruction based on the selected energy transfer mode and parameters.

[0054] Exemplarily, the G2V mode can be selected, and the charging parameters can be selected. Among them, the charging parameters may include the charging duration and / or the charging power of this time. For example, the charging power of this time can be represented by the battery capacity, or it can be represented by the charging interval of the state of charge of the battery.

[0055] Another exemplarily, the V2G mode or the V2L mode can be selected, and the discharge parameters can be selected. Among them, the discharge parameters may include the discharge duration and / or the discharge power of this time. For example, the discharge power of this time can be represented by the battery capacity, or it can be represented by the discharge interval of the state of charge of the battery.

[0056] In one example, when in the first energy transfer mode, the communication module 12 can also calculate the maximum discharge amount according to the battery information sent by the BMS 20, then determine the smaller value between the current discharge amount sent by the user and the calculated maximum discharge amount, and update the smaller value as the new current discharge amount. Through this example, over-discharge of the battery 30 can be avoided, thereby improving the battery safety and service performance.

[0057] In another example, when in the second energy transfer mode, the communication module 11 can also calculate the maximum charge amount according to the battery information sent by the BMS 20, then determine the smaller value between the current charge amount sent by the user and the calculated maximum charge amount, and update the smaller value as the new current charge amount. Through this example, over-charge of the battery 30 can be avoided, thereby improving the battery safety and service performance.

[0058] In one example, after the handshake phase and the configuration phase are completed, that is, after the positive and negative relays of the electric vehicle are both closed, the communication module 11 can calculate the maximum discharge amount or calculate the maximum charge amount.

[0059] For conversion module 12.

[0060] In terms of the connection relationship, one end of the conversion module 12 is connected to the battery 30, and the other end of the conversion module 12 is connected to the AC-side connection structure 40.

[0061] Functionally, the conversion module 12 can achieve the conversion between direct current and alternating current. Specifically, the conversion module 12 is used to convert the direct current provided by the battery 30 into alternating current during the first communication process, and transmit the alternating current to the AC-side connection structure 40.

[0062] In terms of the implementation manner, the conversion module 12 can be implemented as an AC-DC (Direct Current - Alternating Current, DCAC) bidirectional conversion module. Among them, the DCAC bidirectional conversion module can convert the direct current input from the DC side into alternating current and output it to the AC side, and can also convert the alternating current input from the AC side into direct current and output it to the DC side.

[0063] In one example, in order to achieve electrical isolation between the AC-side connection structure 40 and the DC-side battery 30, an isolated bidirectional full-bridge CLLC resonant circuit can be selected. It should be noted that for the direct current output by the power battery of the electric vehicle, its voltage can reach 200V - 500V, while the alternating current on the AC side of the conversion module 12 can often reach 220V or 380V. Electrical isolation between the battery and the AC-side connection structure can improve the safety of electrical equipment and the safety of relevant personnel.

[0064] Exemplarily, the conversion module 12 may include a bidirectional full-bridge ACDC circuit section and a CLLLC DC-DC conversion circuit section. The CLLLC DC-DC conversion circuit section uses an isolation transformer for electrical isolation to prevent the battery 30 and the AC-side connection structure 40 from affecting each other.

[0065] The bidirectional full-bridge ACDC circuit is mainly used to control the transmission of bidirectional active power and reactive power on the grid side, realizing four-quadrant operation of the power on the AC side. The CLLLC DC-DC conversion circuit section is mainly used to adjust the active power transmission on the battery side and control the charging and discharging processes of the battery.

[0066] In the G2V mode, the active power of the conversion module 12 flows from the AC side to the DC side. The bidirectional full-bridge ACDC circuit section operates in the rectification state, presenting the boost circuit step-up characteristic, controlling the AC-side input current and stabilizing the DC-side voltage; the CLLLC DC-DC conversion circuit section delivers the power from the primary side to the secondary side to charge the battery 30 and stabilize the battery-side output voltage or current.

[0067] In the V2G and V2L modes, the active power of the conversion module 12 flows reversely from the DC side to the AC side. The bidirectional full-bridge ACDC circuit section operates in the inversion state, presenting the buck circuit step-down characteristic, controlling the AC-side output current. The CLLLC DC-DC conversion circuit delivers the power from the secondary side to the primary side to discharge the battery and stabilize the DC-side voltage.

[0068] In one embodiment, in order to improve the conversion efficiency of the conversion module 12, the bridge arm switch unit in the DCAC bidirectional conversion module may select a switch unit made of SiC material. Or, the DCAC bidirectional conversion module may implement a synchronous rectification strategy.

[0069] In one embodiment, Figure 2 is a schematic diagram of the power mode of the conversion module provided by the embodiment of the present application. As Figure 2 shown, in the G2V, V2G, and V2L modes, the conversion module 12 operates on the P axis. In addition, the conversion module 12 can also operate on the Q axis in the pure reactive power mode. The conversion module 12 can simultaneously perform active and reactive power transmission, perform reactive power compensation and power factor correction when charging and discharging the battery, and realize the operation of the AC side in the four quadrants of the power circle.

[0070] In some embodiments, when the AC-side connection structure 40 includes an AC-side power source and is in the case of the second energy transmission module, the conversion module 12 is further configured to convert the alternating current provided by the AC-side power source into direct current during the second communication process and transmit the direct current to the battery 30.

[0071] According to the charge-discharge device in the embodiments of the present application, when the battery transmits power to the AC-side connection structure, when the BMS does not support a specific discharge protocol, a general charging protocol can be selected to implement communication between the BMS and the charge-discharge device, so as to realize the discharge of the battery when the BMS does not support the discharge protocol.

[0072] In some embodiments, the charge-discharge device 10 may further include a control module 13. The following part will specifically describe the control module 13.

[0073] For control module 13.

[0074] After the control module 13 receives a control signal through the communication module 11, it can control the conversion module 12 based on the control signal.

[0075] Specifically, the control module 13 can control the current conversion direction of the conversion module 12. For example, it can control the conversion module 12 to convert direct current into alternating current, or it can control the conversion module 12 to convert alternating current into direct current. Exemplarily, Figure 3 is a schematic structural diagram of an exemplary charge-discharge device provided by the embodiments of the present application. As Figure 3 shown, when the charge-discharge device further includes a first switch K1 and a second switch K2, before the conversion module 12 starts to work, the control module 13 can control the first switch K1 and the second switch K2. And, it can also control the first switch K1 and the second switch K2 to disconnect after the charging ends, such as after the G2V mode ends, or after the discharging ends, such as after the V2G mode or the V2L mode ends. It should be noted that the first switch K1 and the second switch K2 can be relays or semiconductor switches, and the specific types of the first switch K1 and the second switch K2 are not limited.

[0076] In one embodiment, in the first energy transfer mode, the control module 13 can obtain discharge parameters through the communication module 11. When the control module 13 determines that the discharge parameters are reached, it controls the conversion module 12 to stop working. Exemplarily, if the discharge parameter includes the discharge duration, the control module 13 controls the conversion module 12 to stop working after determining that the current discharge process reaches the discharge duration. Another exemplarily, if it is determined that the maximum discharge power is reached, the conversion module 12 stops working.

[0077] In addition, the control module 13 can also send a signal to end the first energy transfer mode to the communication module 11. After receiving this signal, the communication module 11 can notify the BMS 20 to end the discharge based on the general charging protocol or the specific discharge protocol. And, the communication module 11 also gives a prompt to the user to end the discharge.

[0078] In another embodiment, in the second energy transfer mode, the control module 13 can obtain the charging parameters through the communication module 11. When the control module 13 determines that the charging parameters are reached, it controls the conversion module 12 to stop working. Exemplarily, if the charging parameters include the charging duration, the control module 13 controls the conversion module 12 to stop working after determining that the current charging process reaches the charging duration. Another example is that if it is determined that the current charging power is reached, the conversion module 12 stops working.

[0079] In addition, the control module 13 can also send a signal to end the second energy transfer mode to the communication module 11. After receiving this signal, the communication module 11 can notify the BMS 20 to end the charging based on the general charging protocol. Also, the communication module 11 gives a prompt to the user to end the charging.

[0080] In one embodiment, to improve safety, in the first sub-mode, before the battery 30 discharges to the AC-side power supply, the control module 13 is further configured to detect whether the voltage and / or voltage frequency of the AC-side power supply are normal at the AC interface of the charging and discharging device. And when the voltage and / or voltage frequency of the AC-side power supply are normal, the control conversion module 12 starts to work. Exemplarily, if the AC-side power supply can be the power grid, that is, the control module 13 can detect whether the voltage and voltage frequency of the power grid are abnormal. When the voltage and voltage frequency of the power grid are abnormal, starting energy transfer is prohibited. Exemplarily, the abnormal standard for voltage can be that the voltage is 0, and the abnormal standard for voltage frequency can be that the voltage frequency is 0.

[0081] Through this embodiment, it is possible to avoid electric shock to personnel caused by AC output when the AC side is not properly connected, improving the safety of the charging and discharging device.

[0082] In some embodiments, to improve safety, the control module 13 is further configured to determine the current energy transfer mode and execute a safety policy corresponding to the current energy transfer mode.

[0083] Specifically, the following part will specifically describe the safety policy in combination with the energy transfer mode.

[0084] (1) If the current energy transfer mode is the first sub-mode, such as the V2G mode, the safety policy corresponding to the first sub-mode includes:

[0085] Policy A: Insulation detection of the battery 30.

[0086] Policy B: Determine that the AC-side voltage parameters of the charging and discharging device 10 are within a preset value range.

[0087] (2) If the current energy transfer mode is the second sub-mode, such as the V2L mode, the safety policy corresponding to the second sub-mode includes:

[0088] Strategy C: Inspect the insulation of the battery 30.

[0089] (3) If the current transmission mode is the second energy transmission mode, such as the G2V mode, the safety strategies corresponding to the second energy transmission mode include:

[0090] Strategy D: Pre-charge the battery 30.

[0091] In some examples, the above safety strategies can be executed during the handshake phase and parameter configuration to ensure the electrical connection safety during the charging / discharging process.

[0092] In some examples, after the first energy transmission mode or the second energy transmission mode ends, the charging and discharging device 10 and the battery can be discharged to ensure the contact safety after power-off.

[0093] In some embodiments, in order to achieve flexible power supply for the charging and discharging device 10, the charging and discharging device 10 may further include an auxiliary power supply 14. The following part will specifically describe the auxiliary power supply 14.

[0094] For auxiliary power supply 14 。

[0095] In terms of the connection relationship, Figure 3 is a schematic structural diagram of an exemplary charging and discharging device provided by an embodiment of the present application. Refer to Figure 3 , which can be connected to the first connection line and the second connection line. Among them, the first connection line is the line between the conversion module 12 and the AC-side connection structure 40. The second connection line is the line between the conversion module 12 and the battery 30. Thus, the function of power supply from the AC-side connection structure 40 or the battery 30 can be realized. In addition, the auxiliary power supply 14 can also be connected to low-voltage electrical components such as the control module 12 to supply power to the low-voltage electrical components.

[0096] Functionally, when the AC-side connection structure 40 includes an AC-side power supply, the auxiliary power supply 14 uses the alternating current provided by the AC-side power supply to supply power to the charging and discharging device 10. Optionally, the auxiliary power supply 14 can also supply power to the low-voltage electrical components of the electric vehicle. For example, through Figure 3 the A+ and A- interfaces in the DC-side interface 17 of, supply power to the low-voltage electrical components of the electric vehicle.

[0097] When the AC-side connection structure 40 includes an AC-side load, before being conducted with the battery 30, the auxiliary power supply 14 uses the direct current provided by the low-voltage power supply to supply power to the charging and discharging device 10, and after being conducted with the battery 30, uses the direct current provided by the battery 30 to supply power to the charging and discharging device 10.

[0098] Among them, the low-voltage power supply includes a built-in battery 15 and / or a vehicle cigarette lighter. Exemplarily, as Figure 3 shown, the auxiliary power supply 14 can be connected to the vehicle cigarette lighter through the cigarette lighter interface 19. For example, the cigarette lighter interface 19 can be implemented as a standard cigarette lighter connector. Exemplarily, the built-in battery 15 can be a low-voltage power supply, such as its voltage can be 12V.

[0099] In one embodiment, for the auxiliary power supply 14, the power supply priority can be, in descending order: the AC side power supply, the battery 30, and the low-voltage power supply. In one example, for the built-in battery 15 and the vehicle cigarette lighter in the low-voltage power supply. The priority of the built-in battery 15 can be higher than that of the vehicle cigarette lighter. Exemplarily, power can be taken from the vehicle cigarette lighter after the power level of the built-in battery 15 is lower than a preset power threshold. Among them, it can be determined whether the power level of the built-in battery 15 is too low through the power level indicator of the built-in battery 15.

[0100] It should be noted that if the charge and discharge device 10 is in a sleep state, it can be powered by the built-in battery 15 or the vehicle cigarette lighter to wake it up.

[0101] In some embodiments, to solve the heat dissipation problem during the operation of the charge and discharge device 10, the charge and discharge device 10 further includes a heat dissipation module 16.

[0102] For heat dissipation module 16 。

[0103] The heat dissipation module 16 is used to dissipate heat from each functional module or physical structure of the charge and discharge device 10, so as to ensure that the heat-dissipated components operate in a suitable temperature range.

[0104] Exemplarily, the heat dissipation module 16 can be specifically implemented as a heat dissipation structure such as a fan or a water cooling module, and its specific structure and type are not limited.

[0105] Correspondingly, the heat dissipation module 16 is connected to the control module 13. The control module 13 collects the temperature of the charge and discharge device 10, and when it determines that the temperature of the charge and discharge device 10 is higher than a preset temperature threshold, it controls the heat dissipation module 16 to start heat dissipation work. Optionally, the ambient temperature of the charge and discharge device 10 or the temperature of the components of the charge and discharge device 10 that are prone to temperature rise can be collected as the temperature of the charge and discharge device 10. Among them, the components prone to temperature rise can be the switching unit of the conversion module 12, or it can be a transformer.

[0106] In addition, the control module 13 also controls the heat dissipation module 16 to stop heat dissipation work when the temperature of the charge and discharge device 10 is lower than the preset temperature threshold, or after the current energy transfer mode ends.

[0107] In some embodiments, in order to connect to the battery 10, the charging and discharging device 10 further includes a DC side interface 17.

[0108] Regarding the DC side interface 17.

[0109] It can be specifically implemented as a DC charging gun. Exemplarily, the DC charging gun can be a DC charging gun compliant with the GB / T 18487 standard.

[0110] In one example, as Figure 3 shown, the DC side interface 17 may include the following interfaces:

[0111] A+ interface and A- interface. Through this interface, the auxiliary power supply 14 can be connected to the low-voltage electrical appliances of the electric vehicle, so that the auxiliary power supply 14 can supply power to the low-voltage electrical appliances of the electric vehicle through this interface. For example, it can supply power to the BMS 20.

[0112] DC+ interface and DC- interface. Through this interface, the conversion module 12 can be connected to the battery 30.

[0113] S+ interface and S- interface. Through this interface, the communication module 11 can implement CAN communication for the BMS 20 or the user interaction terminal.

[0114] CC1 interface, used to detect whether the charging gun is inserted into the electric vehicle.

[0115] CC2 interface, which is vacant.

[0116] PE interface, used for grounding.

[0117] In some embodiments, in order to connect to the AC side connection structure 40, the charging and discharging device 10 further includes an AC side interface 18.

[0118] Regarding the AC side interface 18.

[0119] Among them, the AC side interface is a pin-type plug for standard AC (abbreviation: male head) and a hole-type plug for standard AC (abbreviation: female head).

[0120] In one example, as Figure 3 shown, the AC side interface 18 may include the following interfaces:

[0121] L interface and N interface. The conversion module 12 is connected to the AC side connection structure 40 through the L interface and the N interface.

[0122] PE interface, used for grounding.

[0123] In some embodiments, the charging and discharging device 10 may further include: a third switch QF. Continue to refer to Figure 3, the third switch QF can be arranged on the connection line between the conversion module 12 and the AC side connection structure 40. The conduction or disconnection between the charge and discharge device 10 and the AC side connection structure 40 can be controlled through the third switch QF.

[0124] After a preliminary understanding of the charge and discharge device provided by the embodiments of the present application, the embodiments of the present application will be combined with Figure 4 to elaborate in detail on the power transmission method of the charge and discharge device provided by the embodiments of the present application.

[0125] Figure 4 is a schematic flowchart of a power transmission method of a charge and discharge device provided by an embodiment of the present application. Figure 4 The execution subject of each step in Figure 4 can be the charge and discharge device 10. As

[0126] shown, the power transmission method 400 of the charge and discharge device may specifically include S410 to S420.

[0126] S410, when in the first energy transmission mode and the BMS does not support a specific discharge protocol, perform first communication with the BMS based on the general charging protocol.

[0127] S420, during the first communication, convert the direct current provided by the battery into alternating current and transmit the alternating current to the AC side connection structure.

[0128] Among them, the first energy transmission mode is the mode in which the battery transmits power to the AC side connection structure of the device.

[0129] In some embodiments of the present application, Figure 5 is a schematic flowchart of another power transmission method of a charge and discharge device provided by an embodiment of the present application. As Figure 5 shown, the power transmission method 400 of the charge and discharge device further includes S430.

[0130] S430, when in the first energy transmission mode and the BMS supports a specific discharge protocol, perform first communication with the BMS based on the specific discharge protocol.

[0131] In some embodiments of the present application, the AC side connection structure is an AC power supply, and the power transmission method 400 of the charge and discharge device further includes:

[0132] When in the second energy transmission mode, perform second communication with the BMS based on the general charging protocol; and, during the second communication, convert the alternating current provided by the AC power supply into direct current.

[0133] Among them, the second energy transmission mode is the mode in which the AC power supply transmits power to the battery.

[0134] In some embodiments of the present application, the general charging protocol is obtained by expanding the existing general charging protocol.

[0135] In some embodiments of the present application, the power transmission method 400 of the charge and discharge device further includes:

[0136] Determine the current energy transmission mode;

[0137] Execute the safety policy corresponding to the current energy transmission mode;

[0138] Wherein, if the current energy transmission mode is the first sub-mode of the first energy transmission mode, the safety policy corresponding to the first sub-mode includes: performing insulation detection on the battery, and determining that the AC side voltage parameter of the device is within a preset value range;

[0139] If the current energy transmission mode is the second sub-mode of the first energy transmission mode, the safety policy corresponding to the second sub-mode includes: performing insulation detection on the battery;

[0140] If the current energy transmission mode is the second energy transmission mode, the safety policy corresponding to the second energy transmission mode includes: pre-charging the battery;

[0141] Wherein, the first sub-mode is the mode of the battery transmitting power to the AC side power supply of the device,

[0142] The second sub-mode is the mode of the battery transmitting power to the AC side load of the device,

[0143] The second energy transmission mode is the mode of the AC side power supply of the device transmitting power to the battery.

[0144] In some embodiments of the present application, the power transmission method 400 of the charge and discharge device further includes:

[0145] Determine whether the AC side connection structure of the DC-AC bidirectional conversion device includes an AC power supply;

[0146] If it includes an AC power supply, supply power to the device with the alternating current provided by the AC power supply;

[0147] If it does not include an AC power supply, before obtaining the direct current provided by the battery, supply power to the device with the direct current provided by the auxiliary DC power supply, and after obtaining the direct current provided by the battery, supply power to the device with the direct current provided by the battery;

[0148] Wherein, the auxiliary DC power supply includes the power supply battery of the device and / or the vehicle cigarette lighter.

[0149] According to the power transmission method of the charge and discharge device in the embodiments of the present application, when the battery transmits power to the AC side connection structure, when the BMS does not support a specific discharge protocol, a general charging protocol can be selected to realize the communication between the BMS and the charge and discharge device, so as to realize the discharge of the battery when the BMS does not support the discharge protocol.

[0150] Other details of the power transmission method of the charge and discharge device according to the embodiments of the present application are similar to those of the charge and discharge device described in the above combined Figures 1 to 3 example, and can achieve its corresponding technical effects. For the sake of brevity, they will not be described in detail here.

[0151] It should be clear that the various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments. Among them, the method embodiments are described relatively simply. For related parts, please refer to the description part of the system embodiments. The present application is not limited to the specific steps and structures described above and shown in the figures. Those skilled in the art can make various changes, modifications and additions, or change the order between steps after understanding the spirit of the present application. And, for the sake of brevity, the detailed description of known method technologies is omitted here.

[0152] The functional modules in the above embodiments can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The programs or code segments can be stored in a machine-readable medium or transmitted through a data signal carried in a carrier wave on a transmission medium or a communication link. A "machine-readable medium" can include any medium that can store or transmit information.

Claims

1. A charging and discharging device, characterized in that, the device comprises: a communication module, which is communicatively connected to a battery management system (BMS), and is configured to perform a first communication with the BMS based on a general charging protocol when in a first energy transmission mode and the BMS does not support a specific discharge protocol; a conversion module, one side of the conversion module is connected to a battery, and the other side of the conversion module is connected to an AC side connection structure, and is configured to convert the direct current provided by the battery into alternating current and transmit the alternating current to the AC side connection structure during the first communication; a heat dissipation module, configured to start heat dissipation work when the temperature of the charging and discharging device is higher than a preset temperature threshold; wherein, the first energy transmission mode is a mode in which the battery transmits power to the AC side connection structure of the device.

2. The device according to claim 1, characterized in that, the communication module is further configured to: perform a first communication with the BMS based on the specific discharge protocol when in a first energy transmission mode and the BMS supports the specific discharge protocol.

3. The device according to claim 1, characterized in that, the AC side connection structure includes an AC side power supply, the communication module is further configured to perform a second communication with the BMS based on a general charging protocol when in a second energy transmission mode; the conversion module is further configured to convert the alternating current provided by the AC side power supply into direct current and transmit the direct current to the battery during the second communication; wherein, the second energy transmission mode is a mode in which the AC power supply transmits power to the battery.

4. The control device of the DC-AC bidirectional conversion device according to claim 1, characterized in that, the general charging protocol is obtained by expanding an existing general charging protocol.

5. The device according to claim 1, characterized in that, the device further comprises: a control module, further configured to determine the current energy transmission mode; and execute a security policy corresponding to the current energy transmission mode; wherein, if the current energy transmission mode is a first sub-mode of the first energy transmission mode, the security policy corresponding to the first sub-mode includes: performing insulation detection on the battery, and determining that the AC side voltage parameter of the device is within a preset value range; if the current energy transmission mode is a second sub-mode of the first energy transmission mode, the security policy corresponding to the second sub-mode includes: performing insulation detection on the battery; if the current transmission mode is the second energy transmission mode, the security policy corresponding to the second energy transmission mode includes: pre-charging the battery; wherein, the first sub-mode is a mode in which the battery transmits power to the AC side power supply of the device, the second sub-mode is a mode in which the battery transmits power to the AC side load of the device, the second energy transmission mode is a mode in which the AC side power supply of the device transmits power to the battery.

6. The device according to any one of claims 1-5, characterized in that, the device further comprises: An auxiliary power supply, which is used to supply power to the device with the alternating current provided by the AC-side power supply when the AC-side connection structure includes an AC-side power supply; and, when the AC-side connection structure includes an AC-side load, before conducting with the battery, supplying power to the device with the direct current provided by a low-voltage power supply, and after conducting with the battery, supplying power to the device with the direct current provided by the battery; wherein, the low-voltage power supply includes the battery of the device and / or a vehicle cigarette lighter.

7. The device according to any one of claims 1-5, characterized in that, the device further includes: a first switch, connected to the conversion module, the positive electrode of the battery, and the control module; a second switch, connected to the conversion module, the negative electrode of the battery, and the control module; the control module is further configured to: before controlling the conversion module to start the conversion operation, control the first switch and the second switch to conduct; after the battery finishes discharging or charging, control the first switch and the second switch to disconnect.

8. A power transmission method for a charging and discharging device, characterized in that, the method includes: when in the first energy transmission mode and the battery management system BMS does not support a specific discharge protocol, performing a first communication with the BMS based on a general charging protocol; during the first communication, converting the direct current provided by the battery into alternating current and transmitting the alternating current to the AC-side connection structure; wherein, the first energy transmission mode is a mode in which the battery transmits power to the AC-side connection structure of the device.

9. The method according to claim 8, the method further includes: when in the first energy transmission mode and the BMS supports a specific discharge protocol, performing a first communication with the BMS based on the specific discharge protocol.

10. The method according to claim 8, characterized in that, the AC-side connection structure is an AC power supply, the method further includes: when in the second energy transmission mode, performing a second communication with the BMS based on a general charging protocol; during the second communication, converting the alternating current provided by the AC power supply into direct current; wherein, the second energy transmission mode is a mode in which the AC power supply transmits power to the battery.

11. The method according to claim 8, characterized in that, the general charging protocol is obtained by expanding an existing general charging protocol.

12. The method according to claim 8, characterized in that, the method further includes: determining the current energy transmission mode; executing a security policy corresponding to the current energy transmission mode; wherein, if the current energy transmission mode is the first sub-mode of the first energy transmission mode, the security policy corresponding to the first sub-mode includes: performing an insulation detection on the battery and determining that the AC-side voltage parameter of the device is within a preset value range; if the current energy transmission mode is the second sub-mode of the first energy transmission mode, the security policy corresponding to the second sub-mode includes: performing an insulation detection on the battery; If the current energy transfer mode is the second energy transfer mode, the safety policy corresponding to the second energy transfer mode includes: pre-charging the battery; wherein, the first sub-mode is the mode in which the battery transmits power to the AC side power supply of the device, the second sub-mode is the mode in which the battery transmits power to the AC side load of the device, the second energy transfer mode is the mode in which the AC side power supply of the device transmits power to the battery.

13. The method according to claim 8, characterized in that, the method further includes: determining whether the AC side connection structure of the conversion module includes an AC power supply; if the AC power supply is included, powering the device with the alternating current provided by the AC power supply; if the AC power supply is not included, powering the device with the direct current provided by the auxiliary DC power supply before obtaining the direct current provided by the battery, and powering the device with the direct current provided by the battery after obtaining the direct current provided by the battery; wherein, the auxiliary DC power supply includes the power supply battery of the device and / or the vehicle cigarette lighter.

14. The method according to claim 8, the method further includes: when in the first energy transfer mode, calculating the maximum discharge amount according to the battery information sent by the battery management system; determining the first smaller value between the current discharge amount sent by the user and the calculated maximum discharge amount, and updating the first smaller value as the new current discharge amount.

15. The method according to claim 10, the method further includes: when in the second energy transfer mode, calculating the maximum charge amount according to the battery information sent by the battery management system; determining the second smaller value between the current charge amount sent by the user and the calculated maximum charge amount, and updating the second smaller value as the new current charge amount.

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