Control method and energy storage system

Abstract

The invention discloses a control method of an energy storage system and the energy storage system, the energy storage system comprises a plurality of battery packs, each battery pack comprises a main pack and at least one expansion pack, and the main pack is in communication connection with the expansion pack through a communication bus and is electrically connected with the expansion pack through a power bus. Each battery pack comprises a battery cell module and a plurality of control switches connected in series to the positive electrode of the battery cell module, at least part of the control switches are connected in parallel with a discharging loop, and the control method comprises the steps that in response to a self-checking request, the control switches and the discharging loop are controlled to be in a switched-off or switched-on state so as to detect voltages at the two ends of the control switches; and determining a detection result of the battery pack according to the control switch, the on-off state of the discharge loop and the voltage at the two ends of the control switch, and controlling the main pack and / or the expansion pack to charge and discharge according to the detection result of the battery pack. Therefore, the charging and discharging safety of the energy storage system can be ensured, and the user experience is improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a control method and an energy storage system. Background Art

[0002] Traditional energy storage systems have limitations in capacity and flexibility, and it is difficult to meet current and future energy storage needs. Therefore, the emergence of energy storage expansion systems is of great significance for improving energy utilization efficiency, ensuring grid stability, and promoting the consumption and utilization of renewable energy. Usually, after the energy storage expansion system is powered on, the MOS is turned on and off to control multiple energy storage power supplies to charge and discharge individually or together. In the case of inconsistent voltage platforms, the energy storage power supply with the highest power or the highest voltage is discharged first until the voltage platform is consistent with or lower than that of other energy storage. Then, the energy storage charging and discharging MOS is closed and expanded to the power bus for discharge until all energy storage in the system participates in the power bus discharge. However, since the energy storage expansion system will simultaneously connect multiple energy storage power supplies to the power bus, and the power and voltage platform of each energy storage power supply may be inconsistent due to the customer's usage environment and energy storage differences, if the MOS fails, it may cause abnormal expansion control and affect the user experience. Summary of the invention

[0003] Embodiments of the present application provide a control method for an energy storage system and an energy storage system.

[0004] The control method of the energy storage system of the embodiment of the present application, the energy storage system includes a plurality of battery packs, the battery packs include a main pack and at least one expansion pack, the main pack is communicatively connected to the expansion pack via a communication bus and is electrically connected to the expansion pack via the power bus, each of the battery packs includes a battery module and a plurality of control switches connected in series to the positive electrode of the battery module, wherein at least part of the control switches is connected in parallel with a discharge circuit, and the control method includes:

[0005] In response to a self-test request, controlling the control switch and the discharge loop to be in an off or on state to detect a voltage across the control switch;

[0006] Determining a detection result of the battery pack according to the switch state of the control switch, the discharge circuit, and the voltage across the control switch;

[0007] The main pack and / or the expansion pack are controlled to charge and discharge according to the detection result of the battery pack.

[0008] In some embodiments, the control switch includes a first charging switch, the input end of the first charging switch is connected to the positive electrode of the battery module, and the control switch and the discharge circuit are in an off or closed state to detect the voltage across the control switch, including:

[0009] Controlling the first charging switch to turn off to detect the voltage across the first charging switch;

[0010] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0011] When the voltage difference between the two ends of the first charging switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

[0012] In some embodiments, controlling the control switch and the discharge loop to be in an off state or a closed state to detect the voltage across the control switch includes:

[0013] When the voltage difference between the two ends of the first charging switch is greater than a first voltage threshold, controlling the first charging switch to close to detect the voltage between the two ends of the first charging switch;

[0014] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0015] When the first charging switch is in a closed state and a voltage difference between two ends of the first charging switch is greater than or equal to a second voltage threshold, it is determined that the detection result is abnormal.

[0016] In some embodiments, the control switch further includes a first discharge switch, an input end of the first discharge switch is connected to an output end of the first charging switch, and the control switch and the discharge loop are controlled to be in an off or closed state to detect the voltage across the control switch, including:

[0017] When the first charging switch is in a closed state and the voltage difference between the two ends of the first charging switch is less than the second voltage threshold, controlling the discharge loop to close to detect the voltage at the output end of the first discharge switch;

[0018] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0019] When the voltage at the output terminal of the first discharge switch is greater than or equal to a third voltage threshold, it is determined that the detection result is abnormal.

[0020] In some embodiments, the discharge circuit includes a discharge circuit connected in parallel to both ends of the first discharge switch, and the control switch and the discharge circuit are controlled to be in an off or closed state to detect the voltage across the control switch, including:

[0021] When the voltage at the output end of the first discharge switch is less than the third voltage threshold, controlling the pre-charge loop to be closed and the discharge loop to be disconnected to detect the voltage at both ends of the first discharge switch;

[0022] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0023] In a case where the voltage at the output end of the first discharge switch is less than a fourth voltage threshold, determining that the detection result is abnormal, or;

[0024] In a case where the voltage at the output end of the first discharge switch is greater than or equal to a fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

[0025] In some embodiments, controlling the control switch and the discharge loop to be in an off state or a closed state to detect the voltage across the control switch includes:

[0026] When the voltage at the output end of the first discharge switch is greater than or equal to a fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is greater than the first voltage threshold, the first discharge switch is controlled to be closed and the pre-charge loop is disconnected to detect the voltage at the output end of the first discharge switch;

[0027] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0028] In the case where the voltage across the first discharge switch is greater than or equal to a second voltage threshold, determining that the detection result is abnormal, or

[0029] When the voltage across the first discharge switch is less than a second voltage threshold, it is determined that the detection result is normal.

[0030] In some embodiments, the control switch of the expansion pack further includes a second charging switch and a second discharging switch, one end of the second charging switch is connected to the output end of the first discharging switch, and the second discharging switch is connected to the output end of the second charging switch, and the control switch and the discharge loop are in an off or closed state to detect the voltage across the control switch, including:

[0031] controlling the second discharge switch to be turned off to detect the voltage across the second discharge switch;

[0032] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0033] In a case where the voltage difference across the second discharge switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

[0034] In some embodiments, controlling the control switch and the discharge loop to be in an off state or a closed state to detect the voltage across the control switch includes:

[0035] When the voltage difference across the second discharge switch is greater than a first voltage threshold, controlling the second discharge switch to close to detect the voltage across the second discharge switch;

[0036] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0037] In a case where the second discharge switch is in a closed state and a voltage difference across the second discharge switch is greater than or equal to a second voltage threshold, it is determined that the detection result is abnormal.

[0038] In some embodiments, controlling the control switch and the discharge loop to be in an off state or a closed state to detect the voltage across the control switch includes:

[0039] When the second discharge switch is in a closed state and the voltage difference between the two ends of the second discharge switch is less than a second voltage threshold, controlling the second charge switch to be turned off to detect the voltage between the two ends of the second charge switch;

[0040] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0041] In a case where the second charging switch is in an off state and a voltage difference across the second charging switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

[0042] In some embodiments, controlling the control switch and the discharge loop to be in an off state or a closed state to detect the voltage across the control switch includes:

[0043] When the second charging switch is in an off state and the voltage difference between the two ends of the second charging switch is greater than a first voltage threshold, controlling the second charging switch to close to detect the voltage between the two ends of the second discharging switch;

[0044] Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes:

[0045] In a case where the voltage at the output end of the second discharge switch is greater than a second voltage threshold, determining that the detection result is abnormal; or

[0046] When the voltage at the output terminal of the second discharge switch is less than a second voltage threshold, it is determined that the detection result is normal.

[0047] In some embodiments, the energy storage system further includes a display, and the control method further includes:

[0048] Control the display to display the detection result.

[0049] The energy storage system provided in the embodiment of the present application includes multiple battery packs and a processor, wherein the battery pack includes a main pack and at least one expansion pack, the main pack is communicatively connected to the expansion pack via a communication bus and is electrically connected to the expansion pack via the power bus, each of the battery packs includes a battery cell module and a plurality of control switches connected in series to the positive electrode of the battery cell module, wherein at least some of the control switches are connected in parallel with a discharge circuit, and the processor is used to implement the above-mentioned control method.

[0050] In the control method and energy storage system of the implementation mode of the present application, the processor responds to the self-test request, controls the control switch and the discharge circuit of the battery pack to be in the off or closed state to detect the voltage across the control switch, and determines whether the control switch and the discharge circuit of the battery pack are abnormal based on the switch state of the control switch and the discharge circuit and the voltage across the control switch, and then controls the main pack and / or the expansion pack to be charged and discharged based on the detection result of the battery pack. In this way, the safety of charging and discharging of the energy storage system can be guaranteed, and the user experience is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0052] Figure 1 It is a module schematic diagram of an energy storage system of certain embodiments of the present application.

[0053] Figure 2 It is a partial circuit diagram of a battery management module of certain embodiments of the present application.

[0054] Figure 3 It is a flowchart of a control method for an energy storage system in certain embodiments of the present application.

[0055] Main component numbers

[0056] 100-energy storage system, 10-battery pack, 11-battery cell module, 12-battery management module, 121-controller, 122-control switch, M1-first charging switch, M2-first discharging switch, M3-second charging switch, M4-second discharging switch, 123-discharging circuit, 1231-discharging circuit, 1232-pre-charging circuit, 13-solar charging module, 14-inverter module. DETAILED DESCRIPTION

[0057] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0058] Please combine Figure 1 The present application provides an energy storage system 100, which includes a plurality of battery packs 10 and a processor (not shown in the figure). The battery pack 10 includes a main pack and at least one expansion pack, the main pack is communicatively connected to the expansion pack through a communication bus and electrically connected to the expansion pack through a power bus, each battery pack 10 includes a battery cell module 11 and a plurality of control switches 122 connected in series to the positive electrode of the battery cell module 11, wherein at least part of the control switches 122 are connected in parallel with a discharge circuit 123, the processor can be used to control the control switch 122 and the discharge circuit 123 to be in an off or closed state in response to a self-test request to detect the voltage across the control switch 122; determine the detection result of the battery pack 10 according to the switch state of the control switch 122 and the discharge circuit 123 and the voltage across the control switch 122; control the main pack and / or the expansion pack to charge and discharge according to the detection result of the battery pack 10.

[0059] In the energy storage system 100 of the embodiment of the present application, the processor responds to the self-test request, controls the control switch 122 and the discharge circuit 123 of the battery pack 10 to be in the off or closed state to detect the voltage across the control switch 122, and determines whether the control switch 122 and the discharge circuit 123 of the battery pack 10 are abnormal according to the switch state of the control switch 122 and the discharge circuit 123 and the voltage across the control switch 122, and then controls the main pack and / or the expansion pack to charge and discharge according to the detection result of the battery pack 10, so that the charging and discharging safety of the energy storage system 100 can be ensured and the user experience is improved.

[0060] Please combine Figure 1 and Figure 2 Specifically, the energy storage system 100 may be a photovoltaic energy storage system, and may be a photovoltaic expansion energy storage system. Those skilled in the art may understand that a photovoltaic energy storage system is a system that converts solar energy into electrical energy and stores it for subsequent use. When in use, the stored electrical energy is converted into alternating current through an electric power inverter to provide convenient electricity to users.

[0061] The energy storage system 100 includes a plurality of battery packs 10, and the number of battery packs 10 can be 2, 3, 4, 5, 8, 10 or even more. The actual number of battery packs 10 of the energy storage system 100 can be set according to the energy storage demand, and the specific number is not limited. The plurality of battery packs 10 can be divided into a main pack and an expansion pack according to their functions. There is one main pack, and there can be one or more expansion packs. The main pack can be respectively connected to the expansion pack through a communication bus and the expansion pack through a power bus.

[0062] Each battery pack 10 may include a battery cell module 11, a battery management module 12 (Battery Management System, BMS) and a solar charging module 13. The battery cell module 11 is used to store electric energy, the battery management module 12 is used to manage the charging and discharging of the battery cell module 11, and the solar charging module 13 can be connected to the solar panel to convert sunlight into DC power through the photovoltaic effect. The positive pole of the battery cell module 11 is connected to the battery management module 12, and the negative pole is connected to the solar charging module 13 and the negative bus of the power bus. The battery management module 12 is connected to the negative bus of the power bus, the solar charging module 13 and the communication bus.

[0063] In addition, it should be noted that the main package may also include an inverter module 14, which may be connected to the negative pole of the battery module 11, the solar charging module 13, the power bus and the battery management module 12 respectively, and the inverter is used to realize the conversion of direct current to alternating current. The main package can be connected to an external load or power source through the inverter module 14.

[0064] The battery management module 12 may include a controller 121 and a plurality of control switches 122, wherein the plurality of control switches 122 are connected in series, one end of which is connected to the positive electrode of the battery cell module 11, and the other end of which is connected to the solar charging module 13 and the positive bus of the power bus. The controller 121 may be connected to each control switch 122 to control the on and off of the control switch 122, and the controller 121 of the main package may also be connected to the controller 121 in the expansion package through the communication bus.

[0065] The control switch 122 of each battery pack 10 (including the main pack and the expansion pack) may include a first charging switch M1 and a first discharging switch M2 connected in series, and the expansion pack may also include a second charging switch M3 and a second discharging switch M4. The battery management module 12 may also include a discharge circuit 123, and the discharge circuit 123 may include a discharge circuit 1231 and a pre-charge circuit 1232, wherein the discharge circuit 1231 is connected in parallel at both ends of the first charging switch M1, and the pre-charge circuit 1232 is connected in parallel at both ends of the first discharge switch M2. The controller 121 may also be connected to the discharge circuit 1231 and the pre-charge circuit 1232 respectively to realize the on and off control of the discharge circuit 1231 and the pre-charge circuit 1232.

[0066] The control switch 122 and the switches in the discharge circuit 1231 and the pre-charge circuit 1232 can all be transistors such as MOS tubes, IGBT tubes or triodes. For example, in this embodiment, MOS tubes can be used as an example for explanation. It can be understood that MOS tubes have lower internal resistance, which can reduce energy loss and improve charging and discharging efficiency.

[0067] Furthermore, the battery management module 12 may include a voltage detection unit, which may be respectively connected to both ends of each control switch 122 and may be used to detect the voltage across each control switch 122. The voltage detection unit may also be communicatively connected to the controller 121, thereby transmitting the detected voltage to the controller 121.

[0068] The processor may be the control core (master control) of the energy storage system 100, and may be communicatively connected to the battery management module 12 of each battery pack 10, and is responsible for monitoring, controlling and managing the entire energy storage system 100. The processor may exist in the form of hardware or software. The processor may be an independent component independent of the battery pack 10, and may be communicatively connected to the battery management module 12 of each battery pack 10 by wire or wireless means. The processor may also be a part of a battery pack 10, and may be integrated into the battery pack 10 in the form of hardware or software, or in other words, the battery pack 10 includes a processor. For example, when the processor is integrated into the battery pack 10 as a part of a battery pack 10, the processor may be integrated into the main pack and be communicatively connected to the battery management module 12 of the main pack.

[0069] In this embodiment, the processor can be integrated into the main package as a part of the main package, and the processor can be communicatively connected with the controller 121 of the main package for explanation. It can be understood that the controller 121 of the main package is communicatively connected with the controllers 121 of other expansion packages through a communication bus, thereby realizing communication between the processor and the controller 121 of each battery pack 10.

[0070] The processor may send a control signal to the controller 121 so that the controller 121 can implement switch control of the control switch 122 and detection control of the voltage sampling unit.

[0071] Before the energy storage system 100 receives a power-on or expansion command, the processor can control the power-on and expansion control of other expansion packages after the main package is powered on. After the main package is powered on, the processor controls the main package to enter the self-test logic after the main package completes the internal hardware self-maintaining power supply control. At this time, there is no power supply on the power bus of the energy storage system 100. When the main package self-test is completed and there is no abnormality, the processor can control the first charging switch M1 and the first discharging switch M2 to close through the controller 121, power the power bus, and wake up the connected expansion package, and control the expansion package to enter the self-test logic after the expansion package completes the internal hardware self-maintaining power supply control.

[0072] Please refer to further Figure 1 and Figure 2 In the self-check logic, the processor implements fault detection on the control switch 122 (first charging switch M1, first discharging switch M2, second charging switch M3, second discharging switch M4) and the discharging circuit 123 (pre-charging circuit 1232 and charging circuit) through the controller 121, and when any control switch 122 or the discharging circuit 123 is detected to be abnormal, it is determined that the detection result of the battery pack 10 is abnormal, and the self-check logic is exited. The processor implements the self-check logic through the controller 121 as follows:

[0073] Step 1: Control all control switches 122 (first discharge switch M2, first charging switch M1, if the battery pack 10 is an expansion pack, it also includes a second charging switch M3 and a second discharge switch M4) and discharge circuit 123 (discharge circuit 1231 and pre-charge circuit 1232) in the battery pack 10 to be in the disconnected state, and determine whether the voltage difference between the two ends of the first charging switch M1 (i.e., B+ and PP1 points) is greater than the first voltage threshold (for example, it can be 0.3V). If the judgment condition is met, it means that the first charging switch M1 is normal, and there is no leakage and MOS failure. Then close the first charging switch M1 and enter the second step; if the judgment condition is not met, it is determined that the first charging switch M1 is abnormal, exit the self-test, save the fault, and obtain the fault through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0074] Step 2: Determine whether the voltage difference between the two ends of the first charging switch M1 (points B+ and PP1) is less than a second voltage threshold (for example, 0.2V). If the judgment condition is met, it means that the first charging switch M1 is controlled normally and there is no short circuit at point PP1 (the output end of the first charging switch M1), then close the discharge loop 1231 (discharge the voltage that may exist at the output end P+ of the first discharge switch M2 after the first charging switch M1 is closed) and enter the third step; if the judgment condition is not met (the voltage difference is greater than or equal to the second voltage threshold), otherwise it is determined that the first charging switch M1 is abnormal, disconnect the first charging switch M1 and exit the self-test, save the fault, and obtain the fault through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0075] Step 3: After the discharge circuit 1231 is controlled in the previous step, it is determined whether the voltage at the output end (point P+) of the first discharge switch M2 is less than the third voltage threshold (the current minimum voltage of the energy storage system 100 is 32V, and the third voltage threshold is set to 20V), or after a delay of 300ms, the voltage at the point P+ is determined. If the determination condition is met, it means that the first discharge switch M2 is normal, and there is no leakage or failure. The pre-charge circuit 1232 is closed and the discharge circuit 1231 is disconnected to enter the fourth step; if the determination condition is not met, it is determined that the first discharge switch M2 is abnormal, the first discharge switch M2 and the discharge circuit 1231 are disconnected, and the self-test is exited, the fault is saved, and the fault can be obtained through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0076] Step 4: Determine whether the voltage at the output end (P+ point) of the first discharge switch M2 reaches a fourth voltage threshold (e.g., 85% of the B+ voltage). If not, wait for 300ms. If the condition is still not met, it indicates that the pre-charge circuit 1232 is abnormal. Disconnect the first discharge switch M2 and the pre-charge circuit 1232 and exit the self-test. Save the fault and obtain the fault through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus); if the pre-charged voltage at the output end of the first discharge switch M2 meets the condition, determine whether the two ends (P+ point) of the first discharge switch M2 are abnormal. + and PP1 points) is greater than a first voltage threshold (for example, 0.3V). If the judgment condition is met, it means that the first discharge switch M2 is normal, and there is no leakage, failure or other faults. Then, the first discharge switch M2 is closed and the pre-charge circuit 1232 is disconnected to enter the fifth step; if the judgment condition is not met, it is judged that the first discharge switch M2 is abnormal, the first discharge switch M2 and the pre-charge circuit 1232 are disconnected, and the self-test is exited. The controller 121 is controlled to save the fault and can obtain the fault through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0077] Step 5: Determine whether the voltage difference between the two ends of the first discharge switch M2 (points P+ and PP1) is less than the second voltage threshold (0.2V). If the judgment condition is met, it means that the first discharge switch M2 is controlled normally and there is no short circuit at the output end P+ of the first discharge switch M2. When the battery pack 10 is a main pack, since the main pack does not have the second charging switch M3 and the second discharging switch M4, there is no need to perform self-test in subsequent steps. At this time, the main pack completes the power-on self-test and notifies the processor and exits the self-test; when the battery pack 10 is an expansion pack, the first discharge switch M2 is disconnected and the sixth step is entered; if the voltage judgment condition is not met, it is determined that the first discharge switch M2 is abnormal, the first discharge switch M2 and the first charging switch M1 are disconnected, the self-test is exited, the fault is saved, and the fault can be obtained through the communication interface (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0078] Step 6: This step starts with the self-test logic of the power pack. If there is no second charging switch M3 and second discharging switch M4 on the power pack, the self-test can be exited. Since there is a main pack on the power bus to supply power at this time, the voltage at the output end (EXP+) of the second discharging switch M4 is the power bus voltage. It is determined whether the voltage difference between the two ends (EXP+ and PP2) of the second discharging switch M4 is greater than the first voltage threshold (0.3V). If the judgment condition is met, it means that the second discharging switch M4 is normal, and there is no leakage or failure. The second discharging switch M4 is closed and the seventh step is entered; if the judgment condition is not met, it is determined that the second discharging switch M4 is abnormal, the self-test is exited, the fault is saved, and the self-test result is notified to the processor (if the battery pack 10 is an expansion pack, the self-test result is notified to the processor through the communication bus).

[0079] Step 7: Determine whether the voltage difference between the two ends (EXP+ and PP2) of the second discharge switch M4 is less than the second voltage threshold (0.2V). If the judgment condition is met, it means that the second discharge switch M4 can be controlled normally and there is no short circuit or other fault at the PP2 point, and enter the eighth step; otherwise, it is determined that the second discharge switch M4 is abnormal, the second discharge switch M4 is disconnected and the self-test is exited, the fault is saved, and the self-test result is notified to the processor.

[0080] Step 8: Determine whether the voltage difference between the two ends (P+ and PP2) of the second charging switch M3 is greater than the first voltage threshold (0.3V). If the judgment condition is met, it means that the second charging switch M3 is normal, and there is no leakage, failure or other faults. Close the second charging switch M3 and enter the ninth step; if the judgment condition is not met, it is determined that the second charging switch M3 is abnormal, disconnect the second discharge switch M4 and exit the self-test, save the fault, and notify the processor of the self-test result.

[0081] Step 9: Determine whether the voltage difference between the two ends (P+ and PP2) of the second charging switch M3 is less than the second voltage threshold (0.2V). If the judgment condition is met, it means that the second charging switch M3 can be controlled normally and there is no short circuit or other faults at the P+ point; if the judgment condition is not met, it is determined that the second charging switch M3 is abnormal, the fault is saved and can be obtained through the communication interface. Before exiting the self-test, the second charging switch M3 and the second discharge switch M4 must be disconnected and the self-test result must be notified to the processor before exiting the self-test process.

[0082] After the battery pack completes self-test and obtains the test results, the processor can control the charging and discharging of each battery pack according to the test results of battery pack 10. Specifically, the processor only controls the charging and discharging of battery packs with normal test results. If a battery pack is abnormal, the energy storage power supply will not be charged and discharged.

[0083] Furthermore, the energy storage system 100 may also include a display, which may be connected to the processor. When the processor obtains the test result, it may control the display to display the test result. The test result may be displayed in the display in the form of text, numbers, codes, etc., and the specific display method is not limited. In this way, it is convenient for users to know whether the current status of the device is available when using it, which increases the customer's experience; and it is convenient for troubleshooting, so that customers do not need to send the device back to the after-sales service point to check what is wrong with the device, so that when the customer contacts the customer service, they can inform the fault to assist the after-sales staff to know why the current device cannot be used. In addition, it can eliminate safety hazards and avoid safety accidents. The hardware of the device is checked before each use to avoid uncontrollable safety hazards.

[0084] See also Figure 3 The present application provides a control method, which is applied to the above energy storage system 100. The control method:

[0085] 01, in response to a self-test request, controlling the control switch and the discharge circuit to be in an off or on state to detect the voltage across the control switch;

[0086] 02. Determine the detection result of the battery pack according to the switch states of the control switch and the discharge circuit and the voltage across the control switch; and

[0087] 03. Control the charging and discharging of the main pack and / or expansion pack according to the detection results of the battery pack.

[0088] In the control method of the present application, the processor responds to the self-test request, controls the control switch and the discharge circuit of the battery pack to be in an off or closed state to detect the voltage across the control switch, and determines whether there is an abnormality in the control switch and the discharge circuit of the battery pack according to the switch state of the control switch and the discharge circuit and the voltage across the control switch, and then controls the main pack and / or expansion pack to be charged and discharged according to the detection result of the battery pack. In this way, the charging and discharging safety of the energy storage system can be ensured, and the user experience is improved.

[0089] In step 01, the self-test request may be generated when the energy storage system is powered on, when the energy storage system is to be expanded, or when the energy storage system is to be charged or discharged.

[0090] In step 02, the voltage across the control switch is detected when the control switch and the discharge circuit are in different switch states to determine whether all the control switches and the discharge circuit in the battery pack are faulty or abnormal. If any one of the control switches or the discharge circuit is abnormal, the detection result of the battery pack is determined to be abnormal, and the self-test can be exited.

[0091] In step 03, if a battery pack is abnormal in the test results of the battery pack, the energy storage power supply will not be controlled for charging and discharging. For example, if the battery pack includes a main pack, expansion pack 1, expansion pack 2, and expansion pack 3, and the test results show that the main pack, expansion pack 1, and expansion pack 2 are normal, and expansion pack 3 is abnormal. Then the main pack, expansion pack 1, and expansion pack 2 are controlled to charge and discharge, and expansion pack 3 is no longer controlled to charge and discharge.

[0092] In some embodiments, step 01 includes:

[0093] 011, controlling the first charging switch to be turned off to detect the voltage across the first charging switch;

[0094] Step 02 includes:

[0095] 021, when the voltage difference between the two ends of the first charging switch is less than or equal to the first voltage threshold, it is determined that the detection result is abnormal.

[0096] It should be noted that the first voltage threshold may be 0.3 V. The first charging switch is controlled to be turned off to detect the voltage across the first charging switch for determining whether the first charging switch has a fault such as leakage or failure.

[0097] If the first charging switch is turned off and the voltage difference across the first charging switch is less than or equal to 0.2 volts, if the first charging switch is turned off and the voltage difference across the first charging switch is greater than 0.2 volts, it is confirmed that the first charging switch is normal and there is no leakage or failure. It is determined that the first charging switch has leakage or failure, that is, the detection result of the battery pack corresponding to the first charging switch is abnormal, so the self-test can be ended.

[0098] In this way, it can be detected whether the first charging switch has faults such as leakage and failure.

[0099] In some embodiments, step 01 includes:

[0100] 012, when the voltage difference between the two ends of the first charging switch is greater than the first voltage threshold, control the first charging switch to close to detect the voltage between the two ends of the first charging switch;

[0101] Step 02 includes:

[0102] 022. When the first charging switch is in a closed state and the voltage difference across the first charging switch is greater than or equal to a second voltage threshold, it is determined that the detection result is abnormal.

[0103] It should be noted that the first voltage threshold can be 0.2 volts, and the first charging switch is closed to detect the voltage across the first charging switch to determine whether the control of the first charging switch is normal and whether there is a short circuit. If the first charging switch is in a closed state and the voltage difference across the first charging switch is less than 0.2 volts, it is determined that the control of the first charging switch is normal. If the first charging switch is in a closed state and the voltage difference across the first charging switch is greater than or equal to 0.2 volts, it is determined that the control of the first charging switch is abnormal or there is a short circuit at the output end of the first charging switch. That is, the detection result of the battery pack corresponding to the first charging switch is abnormal, and thus, the self-test can be terminated.

[0104] It should also be noted that after determining that the detection result of the corresponding battery pack is abnormal, the controller can control the first charging switch to be disconnected and then exit the self-test.

[0105] In this way, it is possible to detect whether there is a fault in the control of the first charging switch.

[0106] In some embodiments, step 01 includes:

[0107] 013, when the first charging switch is in a closed state and the voltage difference between the two ends of the first charging switch is less than the second voltage threshold, controlling the discharge loop to close to detect the voltage at the output end of the first discharge switch;

[0108] Step 02 includes:

[0109] 023. When the voltage at the output terminal of the first discharge switch is greater than or equal to the third voltage threshold, it is determined that the detection result is abnormal.

[0110] It can be understood that when the first charging switch is in a closed state, the discharge circuit is closed. If the first charging switch is normal, the first charging switch and the discharge circuit form a closed circuit for discharge, which will cause the voltage at the output end of the first discharge switch to gradually decrease. Therefore, detecting the voltage at the output end of the first discharge switch can determine whether a closed circuit is formed. If the voltage at the output end of the first discharge switch is detected to be less than the third voltage threshold immediately after closing the discharge circuit or after a delay of a preset time threshold (for example, 300 milliseconds), it is determined that the detection result of the discharge of the first discharge switch is normal. If the voltage at the output end of the first discharge switch is greater than or equal to the third voltage threshold, it indicates that the first discharge switch has leakage, failure, or other faults during discharge.

[0111] When the voltage at the output end of the first discharge switch is greater than or equal to the third voltage threshold, the first charging switch and the discharge circuit can be disconnected by the controller and the fault can be saved to confirm that the detection result of the battery pack corresponding to the first charging switch is abnormal.

[0112] The third voltage threshold can be determined by the minimum voltage of the energy storage system. The third voltage threshold is less than the minimum voltage of the energy storage system. For example, when the minimum voltage of the energy storage system is 32 volts, the third threshold voltage can be 15 volts, 16 volts, 18 volts, 20 volts, 22 volts, etc., without limitation.

[0113] In this way, it is possible to detect whether there is a fault such as leakage or failure during discharge of the first charging switch.

[0114] In some embodiments, step 01 includes:

[0115] 014, when the voltage at the output end of the first discharge switch is less than the third voltage threshold, control the pre-charge loop to be closed and the discharge loop to be disconnected, so as to detect the voltage at both ends of the first discharge switch;

[0116] Step 02 includes:

[0117] 024, when the voltage at the output terminal of the first discharge switch is less than the fourth voltage threshold, determining that the detection result is abnormal, or;

[0118] 025, when the voltage at the output end of the first discharge switch is greater than or equal to the fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is less than or equal to the first voltage threshold, it is determined that the detection result is abnormal.

[0119] After controlling the pre-charging circuit to be closed and the discharge circuit to be disconnected, the voltage at both ends of the first discharge switch is detected to determine whether the pre-charging circuit and the first discharge circuit are abnormal, and the detection can be performed immediately after the pre-charging circuit is closed and the discharge circuit is disconnected, or after waiting for a preset time (for example, 300 milliseconds). Among them, the fourth voltage threshold of the voltage at the output end of the first discharge switch is compared to determine whether the pre-charging circuit is abnormal. If the voltage at the output end of the first discharge switch is less than the fourth voltage threshold, it indicates that the pre-charging circuit is abnormal. In the case of an abnormal pre-charging circuit, it is determined that the detection result of the corresponding battery pack is abnormal, the first charging switch and the pre-charging circuit are disconnected, and the self-test is exited.

[0120] The fourth voltage threshold is positively correlated with the positive voltage of the battery module, that is, the larger the positive voltage of the battery module, the larger the fourth voltage threshold. In this embodiment, the fourth voltage threshold can be equal to 85% of the positive voltage of the battery module. That is, the magnitude of the voltage at the output end of the first discharge switch and 85% of the positive voltage of the battery module is determined.

[0121] If the voltage at the output end of the first discharge switch is greater than or equal to the fourth voltage threshold, it indicates that the pre-charge circuit is normal, and then the voltage difference between the two ends of the first discharge switch is compared with the first voltage threshold to determine whether the first discharge switch has leakage or failure. If the voltage difference between the two ends of the first discharge switch is less than or equal to the first voltage threshold, it indicates that the first discharge switch has leakage or failure, and the detection result of the battery pack corresponding to the first discharge switch is determined to be abnormal, so the first charging switch and the pre-charge circuit are disconnected, and the self-test is exited.

[0122] In this way, abnormality detection of the discharge circuit and the first discharge switch in the off state is achieved.

[0123] In some embodiments, step 01 includes:

[0124] 015, when the voltage at the output end of the first discharge switch is greater than or equal to the fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is greater than the first voltage threshold, control the first discharge switch to close and the pre-charge loop to open, so as to detect the voltage at the output end of the first discharge switch;

[0125] Step 02 includes:

[0126] 026, when the voltage across the first discharge switch is greater than or equal to the second voltage threshold, determining that the detection result is abnormal, or

[0127] 027. When the voltage across the first discharge switch is less than the second voltage threshold, it is determined that the detection result is normal.

[0128] The first discharge switch is controlled to be closed and the pre-charge circuit is disconnected. The voltage at the output end of the first discharge switch is detected to determine whether the discharge of the first discharge switch is abnormal. If the difference between the voltages at both ends of the first discharge switch is greater than or equal to the second voltage threshold, it indicates that the discharge of the first discharge switch is abnormal. In the case of abnormal discharge of the first discharge switch, it is determined that the detection result of the corresponding battery pack is abnormal, the first charging switch and the first discharge switch are disconnected, and the self-test is exited.

[0129] If the voltage difference between the two ends of the first discharge switch is less than the second voltage threshold, it indicates that the first discharge switch is discharging normally. It can be understood that since the main pack only includes the first discharge switch, the first charging switch, the discharge circuit and the precharge circuit, if the first discharge switch is closed and there is no abnormality, the detection of the main pack is completed, indicating that there is no abnormality in the main pack. The self-test can be exited, and it is determined that there is no fault in the main pack and charging and discharging can be realized normally.

[0130] In this way, abnormality detection of the first discharge switch in the closed state is achieved.

[0131] In some embodiments, step 01 includes:

[0132] 016, controlling the second discharge switch to be turned off to detect the voltage across the second discharge switch;

[0133] Step 02 includes:

[0134] 028. When the voltage difference across the second discharge switch is less than or equal to the first voltage threshold, it is determined that the detection result is abnormal.

[0135] After the second discharge switch is turned off, the voltage across the second discharge switch is detected to determine whether the second discharge switch has a fault such as leakage or failure. When the voltage difference across the second discharge switch is less than or equal to the first voltage threshold, it is determined that the second discharge switch has a fault such as leakage or failure, and the detection result of the corresponding battery pack is confirmed to be abnormal.

[0136] In this way, it is possible to detect whether the second discharge switch has faults such as leakage and failure.

[0137] In some embodiments, step 01 includes:

[0138] 017, when the voltage difference between the two ends of the second discharge switch is greater than the first voltage threshold, control the second discharge switch to close to detect the voltage between the two ends of the second discharge switch;

[0139] Step 02 includes:

[0140] 029. When the second discharge switch is in a closed state and the voltage difference across the second discharge switch is greater than or equal to the second voltage threshold, it is determined that the detection result is abnormal.

[0141] It should be noted that after controlling the second discharge switch to be closed, the voltage across the second discharge switch is detected to determine whether the second discharge switch is controlled normally and whether there is a short circuit. If the second discharge switch is in a closed state and the voltage difference across the second discharge switch is less than the second voltage threshold, it is determined that the second discharge switch is controlled normally. If the second discharge switch is in a closed state and the voltage difference across the second discharge switch is greater than or equal to the second voltage threshold, it is determined that the second voltage threshold is abnormally controlled or there is a short circuit at the output end of the second voltage threshold. That is, the detection result of the battery pack corresponding to the second discharge switch is abnormal, and thus, the self-test can be terminated.

[0142] It should also be noted that after determining that the detection result of the corresponding battery pack is abnormal, the second discharge switch can be controlled by the controller to be disconnected and then exit the self-test.

[0143] In this way, it is possible to detect whether there is any abnormality in the control of the second discharge switch or a short circuit occurs.

[0144] In some embodiments, step 01 includes:

[0145] 018, when the second discharge switch is in a closed state and the voltage difference across the second discharge switch is less than the second voltage threshold, control the second charge switch to be turned off to detect the voltage across the second charge switch;

[0146] Step 02 includes:

[0147] 0201, when the second charging switch is in the off state and the voltage difference across the second charging switch is less than or equal to the first voltage threshold, determining that the detection result is abnormal.

[0148] When the second discharge switch is closed and the second charging switch is turned off, the voltage across the second charging switch is detected to detect whether the second charging switch has a fault such as leakage or failure. When the voltage difference across the second charging switch is less than or equal to the first voltage threshold, it is determined that the second charging switch has a fault such as leakage or failure, and the detection result of the corresponding battery pack is confirmed to be abnormal.

[0149] In this way, it is possible to detect whether the second charging switch has faults such as leakage and failure.

[0150] In some embodiments, step 01 includes:

[0151] 019, when the second charging switch is in an off state and the voltage difference between the two ends of the second charging switch is greater than the first voltage threshold, control the second charging switch to close to detect the voltage between the two ends of the second discharging switch;

[0152] Step 02 includes:

[0153] 0202, when the voltage at the output end of the second discharge switch is greater than the second voltage threshold, determining that the detection result is abnormal; or

[0154] 0203, when the voltage at the output end of the second discharge switch is less than the second voltage threshold, it is determined that the detection result is normal.

[0155] It should be noted that the second charging switch is closed to detect the voltage across the first charging switch to determine whether the second charging switch is controlled normally and whether there is a short circuit. If the second charging switch is in a closed state and the voltage difference across the second charging switch is less than the second voltage threshold, it is determined that the second charging switch is controlled normally. If the second charging switch is in a closed state and the voltage difference across the second charging switch is greater than or equal to the second voltage threshold, it is determined that the second charging switch is abnormally controlled or there is a short circuit at the output end of the second charging switch. That is, the detection result of the battery pack corresponding to the second charging switch is abnormal. Thus, the self-test can be ended and all control switches can be controlled to turn off.

[0156] In this way, it is possible to detect whether there is any abnormality in the control of the second charging switch or a fault such as a short circuit occurs.

[0157] In some embodiments, the control method further comprises:

[0158] 03. Control the display to display the detection result.

[0159] In this way, users can know whether the status of the energy storage system is available when using it, which improves the customer's usage experience. In addition, it is convenient for users or developers to understand the specific fault, facilitate subsequent maintenance and processing, and improve fault handling efficiency.

[0160] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes a plurality of battery packs, each of which includes a main pack and at least one expansion pack, wherein the main pack is communicatively connected to the expansion pack via a communication bus and electrically connected to the expansion pack via a power bus, each of the battery packs includes a battery cell module and a plurality of control switches connected in series to the positive electrode of the battery cell module, wherein at least some of the control switches are connected in parallel with a discharge circuit, and the control method includes: In response to a self-test request, controlling the control switch and the discharge loop to be in an off or on state to detect a voltage across the control switch; Determining a detection result of the battery pack according to the switch state of the control switch, the discharge circuit, and the voltage across the control switch; The main pack and / or the expansion pack are controlled to charge and discharge according to the detection result of the battery pack.

2. The control method according to claim 1, characterized in that: The control switch includes a first charging switch, the input end of the first charging switch is connected to the positive electrode of the battery module, and the control switch and the discharge circuit are controlled to be in an off or closed state to detect the voltage across the control switch, including: Controlling the first charging switch to turn off to detect the voltage across the first charging switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: When the voltage difference between the two ends of the first charging switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

3. The control method according to claim 2, characterized in that: The controlling the control switch and the discharge circuit to be in an off state or a closed state to detect the voltage across the control switch includes: When the voltage difference between the two ends of the first charging switch is greater than a first voltage threshold, controlling the first charging switch to close to detect the voltage between the two ends of the first charging switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: When the first charging switch is in a closed state and a voltage difference between two ends of the first charging switch is greater than or equal to a second voltage threshold, it is determined that the detection result is abnormal.

4. The control method according to claim 3, characterized in that: The control switch further includes a first discharge switch, the input end of the first discharge switch is connected to the output end of the first charging switch, the discharge circuit includes a discharge circuit connected in parallel at both ends of the first charging switch, and the control switch and the discharge circuit are controlled to be in an off or closed state to detect the voltage at both ends of the control switch, including: When the first charging switch is in a closed state and the voltage difference between the two ends of the first charging switch is less than the second voltage threshold, controlling the discharge loop to close to detect the voltage at the output end of the first discharge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: When the voltage at the output terminal of the first discharge switch is greater than or equal to a third voltage threshold, it is determined that the detection result is abnormal.

5. The control method according to claim 4, characterized in that: The discharge circuit includes a pre-charge circuit connected in parallel at both ends of the first discharge switch, and the control switch and the discharge circuit are controlled to be in an off or closed state to detect the voltage at both ends of the control switch, including: When the voltage at the output end of the first discharge switch is less than the third voltage threshold, controlling the pre-charge loop to be closed and the discharge loop to be disconnected to detect the voltage at both ends of the first discharge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In a case where the voltage at the output end of the first discharge switch is less than a fourth voltage threshold, determining that the detection result is abnormal, or; In a case where the voltage at the output end of the first discharge switch is greater than or equal to a fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

6. The control method according to claim 5, characterized in that: The controlling the control switch and the discharge circuit to be in an off state or a closed state to detect the voltage across the control switch includes: When the voltage at the output end of the first discharge switch is greater than or equal to a fourth voltage threshold and the voltage difference between the two ends of the first discharge switch is greater than the first voltage threshold, the first discharge switch is controlled to be closed and the pre-charge loop is disconnected to detect the voltage at the output end of the first discharge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In the case where the voltage across the first discharge switch is greater than or equal to a second voltage threshold, determining that the detection result is abnormal, or When the voltage across the first discharge switch is less than a second voltage threshold, it is determined that the detection result is normal.

7. The control method according to claim 6, characterized in that: The control switch of the expansion pack further includes a second charging switch and a second discharging switch, one end of the second charging switch is connected to the output end of the first discharging switch, and the second discharging switch is connected to the output end of the second charging switch, and the control switch and the discharging circuit are controlled to be in an off or closed state to detect the voltage across the control switch, including: controlling the second discharge switch to be turned off to detect the voltage across the second discharge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In a case where the voltage difference across the second discharge switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

8. The control method according to claim 7, characterized in that: The controlling the control switch and the discharge circuit to be in an off state or a closed state to detect the voltage across the control switch includes: When the voltage difference across the second discharge switch is greater than a first voltage threshold, controlling the second discharge switch to close to detect the voltage across the second discharge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In a case where the second discharge switch is in a closed state and a voltage difference across the second discharge switch is greater than or equal to a second voltage threshold, it is determined that the detection result is abnormal.

9. The control method according to claim 8, characterized in that: The controlling the control switch and the discharge circuit to be in an off state or a closed state to detect the voltage across the control switch includes: When the second discharge switch is in a closed state and the voltage difference between the two ends of the second discharge switch is less than a second voltage threshold, controlling the second charge switch to be turned off to detect the voltage between the two ends of the second charge switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In a case where the second charging switch is in an off state and a voltage difference across the second charging switch is less than or equal to a first voltage threshold, it is determined that the detection result is abnormal.

10. The control method according to claim 9, characterized in that: The controlling the control switch and the discharge circuit to be in an off state or a closed state to detect the voltage across the control switch includes: When the second charging switch is in an off state and the voltage difference between the two ends of the second charging switch is greater than a first voltage threshold, controlling the second charging switch to close to detect the voltage between the two ends of the second discharging switch; Determining the detection result of the battery pack according to the control switch, the switch state of the discharge circuit and the voltage across the control switch includes: In a case where the voltage at the output end of the second discharge switch is greater than a second voltage threshold, determining that the detection result is abnormal; or When the voltage at the output terminal of the second discharge switch is less than a second voltage threshold, it is determined that the detection result is normal.

11. The control method according to any one of claims 1 to 10, characterized in that: The energy storage system further includes a display, and the control method further includes: Control the display to display the detection result.

12. An energy storage system, characterized in that: The energy storage system includes multiple battery packs and a processor, the battery packs include a main pack and at least one expansion pack, the main pack is communicatively connected to the expansion pack via a communication bus and is electrically connected to the expansion pack via the power bus, each of the battery packs includes a battery cell module and a plurality of control switches connected in series to the positive electrode of the battery cell module, wherein at least some of the control switches are connected in parallel with a discharge circuit, and the processor is used to implement the control method described in any one of claims 1 to 11.

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