Vehicle charging and discharging method, battery management system and charging and discharging system

Abstract

The present invention provides a vehicle charging and discharging method, a battery management system and a charging and discharging system. The method comprises: when it is detected that a vehicle is plugged into a charging gun, charging information is exchanged with a DC charging pile, and if it is determined that the charging preparation conditions are met, a charging state is entered; a discharge request sent by an on-board charger is received, and a charge-discharge power balance strategy is executed according to the discharge request, wherein the charge-discharge power balance strategy is used to avoid charging interruptions and discharging interruptions; in this way, the vehicle can discharge an external load while charging, and execute a charge-discharge power balance strategy to avoid discharging interruptions and charging interruptions; the discharge efficiency is improved, thereby improving the user experience of the discharge function.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle technology, and in particular to a vehicle charging and discharging method, a battery management system, and a charging and discharging system. Background Art

[0002] Currently, all new energy vehicles have a charging function, and some new energy vehicles have an external discharge function. Currently, using the vehicle to discharge electricity externally is a common function. For example, during long-distance trips, it is necessary to power on-board electrical appliances, such as rice cookers, car refrigerators, etc.

[0003] However, when new energy vehicles are discharging electricity, they are currently unable to discharge high-power loads while charging. So when the vehicle is charging at a charging station with insufficient power, it cannot supply power to external loads, which directly affects the use of external loads; for example, if a rice cooker is being used to cook in the car, then cooking cannot continue at this time.

[0004] It can be seen that new energy vehicles cannot discharge while charging, which will seriously affect the discharge efficiency and affect the user experience of the discharge function. Summary of the invention

[0005] In response to the problems existing in the prior art, the embodiments of the present invention provide a vehicle charging and discharging method, a battery management system and a charging and discharging system to solve or partially solve the technical problem that new energy vehicles cannot discharge external loads while charging, affecting the discharge efficiency and further affecting the user experience of the discharge function.

[0006] The present invention provides a vehicle charging and discharging method, which is applied in a battery management system. The method comprises:

[0007] When it is detected that the vehicle is plugged into the charging gun, it interacts with the DC charging pile for charging information. If it is determined that the charging preparation conditions are met, it enters the charging state;

[0008] A discharge request sent by an on-board charger is received, and a charge-discharge power balance strategy is executed according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0009] In the above solution, executing the charge-discharge power balancing strategy according to the discharge request includes:

[0010] Get the current state of charge (SOC) value;

[0011] If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is greater than or equal to a preset threshold, the charging current is controlled to reach a maximum value.

[0012] In the above solution, if it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is less than a preset threshold, the method further includes:

[0013] Obtaining the sum of the vehicle load power and the external discharge power of the on-board charger;

[0014] The charging power is controlled to be consistent with the power and value.

[0015] In the above solution, after controlling the charging power to be consistent with the power sum value, the method further includes:

[0016] Collecting the current SOC value of the vehicle at a preset collection period;

[0017] The difference between the charge-cutoff SOC value and the current SOC value is controlled to be less than or equal to the preset threshold.

[0018] In the above solution, after executing the charge-discharge power balancing strategy according to the discharge request, the method further includes:

[0019] If a stop-discharging instruction sent by the on-board charger is received, the charge-discharge balance strategy is abandoned and the pure charging state is entered.

[0020] A second aspect of the present invention provides a battery management system, the battery management system comprising:

[0021] The detection unit is used to interact with the DC charging pile for charging information when it detects that the vehicle is plugged into the charging gun, and enter the charging state if it is determined that the charging preparation conditions are met;

[0022] The execution unit is used to receive a discharge request sent by the on-board charger and execute a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0023] In the above solution, the execution unit is specifically used for:

[0024] Get the current state of charge value SOC;

[0025] If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is greater than or equal to a preset threshold, the charging current is controlled to reach a maximum value.

[0026] In the above solution, the execution unit is specifically used for:

[0027] Obtaining the sum of the vehicle load power and the external discharge power of the on-board charger;

[0028] The charging power is controlled to be consistent with the power and value.

[0029] In the above solution, the system further comprises: a control unit, which is used to:

[0030] Collecting the current SOC value of the vehicle at a preset collection period;

[0031] The difference between the charge-cutoff SOC value and the current SOC value is controlled to be less than or equal to the preset threshold.

[0032] A third aspect of the present invention provides a vehicle charging and discharging system, the system comprising:

[0033] The battery management system is used to interact with the DC charging pile for charging information when it detects that the vehicle is plugged into a charging gun. If it is determined that the charging preparation conditions are met, it enters the charging state;

[0034] The on-board charger is used to send a discharge request to the battery management system, and start the discharge function when the discharge request is confirmed;

[0035] The battery management system is also used to: receive the discharge request sent by the on-board charger, and execute a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0036] The present invention provides a vehicle charging and discharging method, a battery management system and a charging and discharging system. The method comprises: when it is detected that a vehicle is plugged into a charging gun, charging information is exchanged with a DC charging pile, and if it is determined that the charging preparation conditions are met, a charging state is entered; a discharge request sent by an on-board charger is received, and a charge-discharge power balance strategy is executed according to the discharge request, wherein the charge-discharge power balance strategy is used to avoid charging interruptions and discharging interruptions; in this way, the vehicle can discharge an external load while charging, and execute a charge-discharge power balance strategy to avoid discharging interruptions and charging interruptions; the discharge efficiency is improved, thereby improving the user experience of the discharge function. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0038] In the attached picture:

[0039] Figure 1 A schematic diagram of a vehicle charging and discharging system provided by an embodiment of the present invention is shown;

[0040] Figure 2A schematic flow chart of a vehicle charging and discharging method provided by an embodiment of the present invention is shown;

[0041] Figure 3 A schematic structural diagram of a vehicle charging and discharging device provided in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0042] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0043] In order to better understand the technical solution of this application, the vehicle charging and discharging system is first introduced here. Figure 1 As shown, the charging and discharging system includes: a battery management system (BMS, Battery Management System) and an on-board charger (OBC, On Board Charger).

[0044] The battery management system BMS is used to interact with the DC charging pile for charging information when it detects that the vehicle is plugged into a charging gun. If it is determined that the charging preparation conditions are met, it enters the charging state;

[0045] The on-board charger OBC is used to send a discharge request to the battery management system BMS, and when the discharge request is confirmed, the discharge function is turned on;

[0046] The battery management system BMS is also used to: receive a discharge request sent by the on-board charger OBC, and execute a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0047] The vehicle of this embodiment generally includes a DC charging interface 11 and an AC charging interface 12 . When charging and discharging an external load at the same time, the DC charging interface 11 can be used for charging and the AC charging interface 12 can be used for discharging.

[0048] When the vehicle needs to discharge an external load while charging, the user can insert the charging gun of the DC charging pile 13 into the vehicle DC charging interface 11, connect one end of the discharge gun 14 to the AC charging interface 12, and connect the other end of the discharge gun 14 to the external load 15 to supply power to the external load. For example, the external load 15 may include: an electric rice cooker, a kettle, an external speaker, a car refrigerator, etc.

[0049] Specifically, the charging gun of the DC charging pile is equipped with many interfaces for connecting to the vehicle, such as the charging interface at the pile end, the grounding interface at the pile end (PE interface), the charging connection confirmation interface at the pile end (CC interface), the control confirmation interface at the pile end (CP interface), etc. The vehicle end also has corresponding interfaces, such as the charging interface at the vehicle end, the PE interface at the vehicle end, the CC interface at the vehicle end, the CP interface at the vehicle end, etc.

[0050] Similarly, the gun head of the discharge gun is provided with many interfaces for connecting with the vehicle, such as a discharge interface, a grounding interface, a discharge connection confirmation interface, a control confirmation interface, and the like.

[0051] The wiring of the vehicle-side charging interface and the wiring of the pile-side charging interface are set correspondingly, and the two work together to realize the charging function. The wiring of the vehicle-side charging interface and the wiring of the pile-side charging interface are both implemented in the control guidance circuit. The control guidance circuit is a circuit specified in the national standard. The control guidance circuit is a communication circuit for charging between the DC charging pile and the vehicle. Among them, the control guidance circuit contains the pile-side detection point 1 and the vehicle-side detection point 2. When the user inserts the charging gun of the DC charging pile 13 into the DC charging interface 11, the DC charging pile 13 and the vehicle's BMS will detect the user's gun insertion action. At this time. When the DC charging pile 13 detects that the voltage of detection point 1 jumps to 4v, it confirms that the charging gun is successfully connected. Similarly, when the vehicle detects that the voltage of detection point 2 jumps to 6v, it confirms that the charging gun is successfully connected.

[0052] After the plug is plugged in, the DC charging pile 13 and the vehicle end begin to send identification messages to each other to determine the necessary parameter information of the battery and the charger. Then the vehicle end and the pile end enter the mutual configuration stage. The OBC sends the maximum output capacity message of the charger to the BMS. The BMS determines whether charging can be performed based on the maximum output capacity of the OBC. If it is sufficient, the vehicle end controls the charging line to be turned on, and the vehicle enters the state of preparing for charging.

[0053] After the above charging preparation conditions are met, the vehicle enters the charging state. The vehicle side will send a message to the charging pile 13 to set the battery charging requirements according to the BMS requirements. The pile side will adjust the charging voltage, current and other requirements in real time according to the message parameters to ensure the normal charging process. At the same time, the two will continue to send real-time charging status information to each other to monitor each other's status.

[0054] During the charging process, if it is necessary to discharge the external load, the user can insert one end of the discharge gun 14 into the AC charging interface 12 of the vehicle, and connect the other end to the external load 15. At this time, if the OBC detects that the resistance value of the corresponding detection point jumps to the corresponding resistance value when the discharge gun 14 is successfully connected, it sends a discharge request to the BMS.

[0055] After receiving the discharge request, the BMS sends a discharge confirmation message to the OBC, and executes the charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0056] After receiving the discharge confirmation information, OBC starts the discharge function and discharges to the external load. During the discharge process, it reports the external discharge power to BMS in real time.

[0057] Among them, the specific implementation method of the BMS executing the charging and discharging power balancing strategy will be specifically described in the subsequent embodiments of the battery management system side, so it will not be repeated here.

[0058] Based on the same inventive concept, this embodiment also provides a vehicle discharging method, which is applied in a battery management system BMS, such as Figure 2 As shown, the method comprises the following steps:

[0059] S210, when it is detected that the vehicle is plugged into the charging gun, the charging information is exchanged with the DC charging pile, and if it is determined that the charging preparation conditions are met, the charging state is entered.

[0060] As mentioned above, when the vehicle needs to discharge the external load while charging, the user can insert the charging gun of the DC charging pile into the DC charging interface of the vehicle. There are many interfaces for connecting to the vehicle in the gun head of the charging gun of the DC charging pile. For example, the pile end charging interface, the pile end grounding interface (PE interface), the pile end charging connection confirmation interface (CC interface), the pile end control confirmation interface (CP interface), etc. The vehicle end also has corresponding interfaces, such as the vehicle end charging interface, the vehicle end PE interface, the vehicle end CC interface, the vehicle end CP interface, etc.

[0061] The wiring of the vehicle-side charging interface and the wiring of the pile-side charging interface are set correspondingly, and the two work together to realize the charging function. The wiring of the vehicle-side charging interface and the wiring of the pile-side charging interface are both implemented in the control guidance circuit. The control guidance circuit is a circuit specified in the national standard, specifically a communication circuit for charging between the DC charging pile and the vehicle. Among them, the control guidance circuit includes the pile-side detection point 1 and the vehicle-side detection point 2. When the user inserts the charging gun of the DC charging pile into the DC charging interface, the DC charging pile and the vehicle's BMS will detect the user's gun insertion action. When the DC charging pile 13 detects that the voltage of detection point 1 jumps to 4v, it confirms that the charging gun is successfully connected. Similarly, when the vehicle detects that the voltage of detection point 2 jumps to 6v, it confirms that the charging gun is successfully connected.

[0062] After the plug is plugged in, the DC charging pile 13 and the vehicle end begin to send identification messages to each other to determine the necessary parameter information of the battery and the charger. Then the vehicle end and the pile end enter the mutual configuration stage. The OBC sends the maximum output capacity message of the charger to the BMS. The BMS determines whether charging can be performed based on the maximum output capacity of the OBC. If it is sufficient, the vehicle end controls the charging line to be turned on, and the vehicle enters the state of preparing for charging.

[0063] After all the above charging preparation conditions are met, the vehicle enters the charging state. The vehicle side will send a message to the charging pile to set the battery charging requirements according to the BMS requirements. The pile side will adjust the charging voltage, current and other requirements in real time according to the message parameters to ensure the normal charging process. At the same time, the two will continue to send real-time charging status information to each other to monitor each other's status.

[0064] S211, receiving a discharge request sent by the on-board charger, and executing a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0065] In this embodiment, one end of the discharge gun is connected to the AC charging interface 12, and the other end of the discharge gun 14 is connected to an external load to supply power to the external load. For example, the external load may include: an electric rice cooker, a kettle, an external speaker, a car refrigerator, etc.

[0066] Similarly, the gun head of the discharge gun is provided with many interfaces for connecting with the vehicle, such as a discharge interface, a grounding interface, a discharge connection confirmation interface, a control confirmation interface, and the like.

[0067] During the charging process, if it is necessary to discharge the external load, the user can insert one end of the discharge gun into the AC charging port of the vehicle and connect the other end to the external load. At this time, if the OBC detects that the resistance value of the corresponding detection point jumps to the corresponding resistance value when the discharge gun is successfully connected, it will send a discharge request to the BMS.

[0068] After receiving the discharge request, the BMS sends a discharge confirmation message to the OBC, and executes the charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0069] After receiving the discharge confirmation information, OBC starts the discharge function and discharges to the external load. During the discharge process, it reports the external discharge power to BMS in real time.

[0070] In one implementation, executing a charge-discharge power balancing strategy according to a discharge request includes:

[0071] Get the current state of charge SOC value;

[0072] If it is determined that the difference between the vehicle's charge cut-off SOC value and the current SOC value is greater than or equal to a preset threshold, the charging current is controlled to reach a maximum value. The preset threshold can be determined based on the actual situation of the vehicle, such as 2-3%, which is not limited here.

[0073] In one embodiment, if it is determined that the difference between the charging cut-off SOC value and the current SOC value of the vehicle is less than a preset threshold, the method further includes:

[0074] Obtain the total vehicle load power and the external discharge power of the on-board charger;

[0075] Control the charging power to be consistent with the power sum value. For example, control the charging power to be equal to the power sum value to avoid stopping charging after charging reaches the charging cut-off SOC.

[0076] It is worth noting that during the charging and discharging process, in order to avoid charging interruption and discharging interruption, after controlling the charging power to be consistent with the power sum value, the method also includes:

[0077] Collect the current SOC value of the vehicle at a preset collection period;

[0078] The difference between the charge cut-off SOC value and the current SOC value is controlled to be less than or equal to a preset threshold.

[0079] That is, assuming that when the threshold is 3%, it is necessary to control the difference between the charge cut-off SOC value and the current SOC value to be less than or equal to 3%.

[0080] Furthermore, during the charging process, if there is no need to power the external load, the user can unplug the discharge gun. At this time, the OBC will detect the instruction to stop discharging and send a stop discharge message to the BMS. When the BMS receives the message of the stop discharge instruction, it will no longer execute the charge and discharge power balance strategy, and the vehicle will enter a pure charging state.

[0081] When the vehicle or charging pile receives a stop charging instruction sent by the user, charging ends.

[0082] Therefore, the vehicle can discharge external loads while charging, and implement a charge-discharge power balance strategy to avoid discharge and charging interruptions; improve discharge efficiency, and thus improve the user experience of the discharge function. In addition, it can supply power to external loads without consuming the power of the new energy vehicle itself, ensuring the endurance of the new energy vehicle and avoiding users' anxiety about power consumption.

[0083] Based on the same inventive concept, this embodiment also provides a battery management system, such as Figure 3 As shown, the battery management system includes:

[0084] The detection unit 31 is used to interact with the DC charging pile for charging information when it is detected that the vehicle is plugged into the charging gun, and enter the charging state if it is determined that the charging preparation conditions are met;

[0085] The execution unit 32 is used to receive a discharge request sent by the on-board charger and execute a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption.

[0086] In one implementation, the execution unit 32 is specifically configured to:

[0087] Get the current state of charge SOC value;

[0088] If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is greater than or equal to a preset threshold, the charging current is controlled to reach a maximum value.

[0089] The execution unit 32 is specifically used for:

[0090] Obtaining the sum of the vehicle load power and the external discharge power of the on-board charger;

[0091] The charging power is controlled to be consistent with the power and value.

[0092] Continue to refer Figure 3 The system further comprises: a control unit 33, configured to:

[0093] Collecting the current SOC value of the vehicle at a preset collection period;

[0094] The difference between the charge-cutoff SOC value and the current SOC value is controlled to be less than or equal to the preset threshold.

[0095] Since the device introduced in the embodiment of the present invention is a device used to implement the vehicle charging and discharging method of the embodiment of the present invention, based on the method introduced in the embodiment of the present invention, the person skilled in the art can understand the specific structure and deformation of the device, so it is not repeated here. All devices used in the method of the embodiment of the present invention belong to the scope of protection of the present invention.

[0096] The vehicle charging and discharging method, battery management system and charging and discharging system provided by the embodiments of the present invention can bring at least the following beneficial effects:

[0097] The present invention provides a vehicle charging and discharging method, a battery management system and a charging and discharging system. The method comprises: when it is detected that a vehicle is plugged into a charging gun, charging information is exchanged with a DC charging pile, and if it is determined that the charging preparation conditions are met, a charging state is entered; a discharge request sent by an on-board charger is received, and a charge-discharge power balance strategy is executed according to the discharge request, wherein the charge-discharge power balance strategy is used to avoid charging interruptions and discharging interruptions; in this way, the vehicle can discharge an external load while charging, and execute a charge-discharge power balance strategy to avoid discharging interruptions and charging interruptions; the discharge efficiency is improved, thereby improving the user experience of the discharge function.

[0098] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle charging and discharging method, characterized in that: Applied in a battery management system, the method comprises: When it is detected that the vehicle is plugged into the charging gun, it exchanges charging information with the DC charging pile. If it is determined that the charging preparation conditions are met, it enters the charging state; receiving a discharge request sent by an on-board charger, and executing a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption; The executing a charge-discharge power balancing strategy according to the discharge request includes: Get the current state of charge SOC value; If it is determined that the difference between the charging cut-off SOC value and the current SOC value of the vehicle is greater than or equal to a preset threshold, controlling the charging current to reach a maximum value; If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is less than a preset threshold, the method further includes: Obtaining the power sum of the vehicle load power and the external discharge power of the on-board charger; The charging power is controlled to be consistent with the power and value.

2. The method according to claim 1, characterized in that After controlling the charging power to be consistent with the power and value, the method further includes: Collecting the current SOC value of the vehicle at a preset collection period; The difference between the charge-cutoff SOC value and the current SOC value is controlled to be less than or equal to the preset threshold.

3. The method according to claim 1, characterized in that After executing the charge-discharge power balancing strategy according to the discharge request, the method further includes: If a stop-discharging instruction sent by the on-board charger is received, the charging and discharging power balancing strategy is abandoned and the pure charging state is entered.

4. A battery management system, characterized in that: The battery management system comprises: The detection unit is used to interact with the DC charging pile for charging information when it detects that the vehicle is plugged into the charging gun, and enter the charging state if it is determined that the charging preparation conditions are met; An execution unit, configured to receive a discharge request sent by an on-board charger, and execute a charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption; The execution unit is specifically used for: Get the current state of charge value SOC; If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is greater than or equal to a preset threshold, controlling the charging current to reach a maximum value; The execution unit is specifically used for: If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is less than a preset threshold, obtaining a power sum of the vehicle load power and the external discharge power of the on-board charger; The charging power is controlled to be consistent with the power and value.

5. The battery management system according to claim 4, characterized in that: The system further comprises a control unit, configured to: Collecting the current SOC value of the vehicle at a preset collection period; The difference between the charge-cutoff SOC value and the current SOC value is controlled to be less than or equal to the preset threshold.

6. A vehicle charging and discharging system, characterized in that: The system comprises: The battery management system is used to interact with the DC charging pile for charging information when it detects that the vehicle is plugged into a charging gun. If it is determined that the charging preparation conditions are met, it enters the charging state; The on-board charger is used to send a discharge request to the battery management system, and start the discharge function when the discharge request is confirmed; The battery management system is also used to: receive the discharge request sent by the on-board charger, and execute the charge-discharge power balance strategy according to the discharge request; the charge-discharge power balance strategy is used to avoid charging interruption and discharging interruption; wherein, The executing a charge-discharge power balancing strategy according to the discharge request includes: Get the current state of charge SOC value; If it is determined that the difference between the charging cut-off SOC value and the current SOC value of the vehicle is greater than or equal to a preset threshold, controlling the charging current to reach a maximum value; If it is determined that the difference between the charging cut-off SOC value of the vehicle and the current SOC value is less than a preset threshold, the method further includes: Obtaining the power sum of the vehicle load power and the external discharge power of the on-board charger; The charging power is controlled to be consistent with the power and value.

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