Energy storage system

Abstract

The invention relates to the technical field of energy storage, and discloses an energy storage system, which comprises an auxiliary power supply unit, a battery management system, an energy management system, an energy storage converter and a battery, and the auxiliary power supply unit is respectively connected with the controller, the battery management system and the energy management system in the energy storage converter so as to supply power to the controller, the battery management system and the energy management system. According to the energy storage system, multiple devices in the energy storage system can directly take electricity from the battery, the auxiliary power supply does not need to be powered through a UPS, and the cost of the energy storage system is reduced. And when the AC power grid is recovered, the auxiliary power supply can be automatically awakened to supply power, field maintenance is not needed, and the difficulty of field maintenance is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to an energy storage system. Background Art

[0002] There are many modules inside the energy storage system, such as BMS (Battery management system), EMS (Energy Management System), PCS (Power Conversion System), etc. This requires multiple auxiliary power supplies to provide stable power supply.

[0003] At present, there are two main ways to obtain power for energy storage systems: Method 1: Directly obtain power from AC. Figure 1 As shown, the BMS in the high-voltage box does not directly draw power from the grid, but supplies power to the auxiliary power supply through the UPS. When the energy storage system is abnormal or the battery power is low and charging conditions are not met, the BMS cuts off the contactor KM1, and the subsequent system will not be able to continue to draw power from the battery, avoiding emptying the battery and damaging the battery. Method 2: Draw power from the battery DC. Figure 2 As shown: the trip switch QF1 is used, and the auxiliary power supply is taken from the tripper. When the system is abnormal or the battery power is low and the charging condition is not met, the trip switch QF1 is tripped, which can effectively avoid the problem of battery emptying and power failure of the grid.

[0004] However, both of the above methods have certain defects. For example, when method 1 is adopted, it is expensive because an additional UPS is required. When method 2 is adopted, when the AC power grid is restored and the conditions for power replenishment are met, the system cannot recover by itself and the operation and maintenance personnel need to go to the site to reclose the trip switch. Summary of the invention

[0005] In view of this, the present invention provides an energy storage system to solve the problem that the main power supply method of the current energy storage system is expensive and lacks self-recovery capability.

[0006] The present invention provides an energy storage system, which includes: an auxiliary power supply unit, a battery management system, an energy management system, an energy storage converter and a battery, wherein:

[0007] The auxiliary power supply unit is connected to the battery so that the auxiliary power supply draws power from the battery, and the auxiliary power supply unit is respectively connected to the controller in the energy storage converter, the battery management system and the energy management system to supply power to the controller, the battery management system and the energy management system;

[0008] When the energy storage system operates normally or the power grid is powered off, the auxiliary power supply unit draws power directly from the battery to provide auxiliary power to the controller in the energy storage inverter, the battery management system and the energy management system; when the controller, the battery management system or the energy management system detects fault information, the auxiliary power supply unit stops drawing power from the battery; when the power grid is restored, the auxiliary power supply unit restarts according to the wake-up signal of the power grid.

[0009] The energy storage system provided by the present invention enables multiple devices in the energy storage system to directly draw power from the battery, without the need to supply power to the auxiliary power supply through a UPS, thereby reducing the cost of the energy storage system. When the AC power grid is restored, the auxiliary power supply can be automatically awakened for power supply, without the need for on-site maintenance, thereby reducing the difficulty of on-site maintenance. In addition, the energy storage system has a software-controlled auxiliary power supply shutdown function, and after the auxiliary power supply is shut down, it no longer draws power from the battery, thereby having a function of preventing battery power loss.

[0010] In an optional embodiment, the auxiliary power supply unit includes a first auxiliary power supply, one end of the first auxiliary power supply is connected to the battery, and the other end of the first auxiliary power supply is connected to the battery management system and the energy management system respectively;

[0011] When the energy storage system operates normally or the power grid is powered off, the first auxiliary power supply directly draws power from the battery to provide auxiliary power to the battery management system and the energy management system; when the battery management system or the energy management system detects fault information, the energy management system sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery; when the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

[0012] In an optional implementation, the other end of the first auxiliary power supply is also connected to a controller in the energy storage converter;

[0013] When the energy storage system operates normally or the power grid is powered off, the first auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller detects fault information, the controller sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery; when the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

[0014] In an optional embodiment, the auxiliary power supply unit further includes a second auxiliary power supply, one end of the second auxiliary power supply is connected to the battery, and the other end of the second auxiliary power supply is connected to the controller;

[0015] When the energy storage system operates normally or the power grid is powered off, the second auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller, the battery management system or the energy management system detects fault information, the controller sends a power-off signal to the second auxiliary power supply, and the second auxiliary power supply stops drawing power from the battery; when the power grid is restored, the second auxiliary power supply restarts according to the wake-up signal of the power grid.

[0016] In an optional implementation, the second auxiliary power supply is disposed in the energy storage inverter.

[0017] In an optional implementation, the battery management system is communicatively connected to the energy management system, the energy management system is communicatively connected to the controller, and the battery management system is communicatively connected to the controller.

[0018] In an optional implementation, the first auxiliary power supply and the second auxiliary power supply are flyback power supplies with isolated outputs.

[0019] In an optional implementation, the energy storage system further includes: a battery monitoring system, a supporting subsystem and an energy storage converter monitoring system, wherein:

[0020] The battery monitoring system is used to monitor the status information of the battery and send the status information to the battery management system;

[0021] The supporting subsystem sends its own operating information to the energy management system EMS;

[0022] The energy storage converter monitoring system is used to monitor the operation information of the energy storage converter and send the operation information to the controller.

[0023] In an optional embodiment,

[0024] The battery management system determines the received status information, and when the status information meets a preset trigger condition, the battery management system sends a stop power supply signal to the auxiliary power supply unit;

[0025] The energy management system determines the received operation information, and when the operation information meets a preset trigger condition, the energy management system sends a stop power supply signal to the auxiliary power supply unit;

[0026] The controller determines the received operation information, and when the operation information meets a preset trigger condition, the controller sends a stop power supply signal to the auxiliary power supply unit.

[0027] In an optional implementation, the preset trigger conditions include: battery abnormality, energy storage system failure, and power grid abnormality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of an existing energy storage system;

[0030] Figure 2 is another schematic diagram of the existing energy storage system;

[0031] Figure 3 is a schematic diagram of an energy storage system according to an embodiment of the present invention;

[0032] Figure 4 is another schematic diagram of an energy storage system according to an embodiment of the present invention;

[0033] Figure 5 is another schematic diagram of an energy storage system according to an embodiment of the present invention;

[0034] Figure 6 is another schematic diagram of an energy storage system according to an embodiment of the present invention;

[0035] Figure 7 is a schematic diagram of an auxiliary power supply circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0037] The present invention provides an energy storage system, which enables multiple devices in the energy storage system to directly draw power from the battery. Figure 3As shown, the energy storage system includes: an auxiliary power supply unit, a battery management system BMS, an energy management system EMS, an energy storage converter PCS and a battery. Among them, the auxiliary power supply unit is connected to the battery so that the auxiliary power supply draws power from the battery, and the auxiliary power supply unit is respectively connected to the controller, the battery management system BMS and the energy management system EMS in the energy storage converter PCS to supply power to the controller, the battery management system BMS and the energy management system EMS. When the energy storage system operates normally or the power grid is powered off, the auxiliary power supply unit draws power directly from the battery to provide auxiliary power to the controller, the battery management system BMS and the energy management system EMS in the energy storage converter PCS. When the controller, the battery management system BMS or the energy management system EMS detects fault information, the auxiliary power supply unit stops drawing power from the battery. When the power grid is restored, the auxiliary power supply unit restarts according to the wake-up signal of the power grid.

[0038] Specifically, the energy storage converter PCS includes a power conversion unit, the battery outputs direct current, which is connected to the DC input terminal of the energy storage converter PCS, and the power conversion is performed in the energy storage converter PCS to output alternating current, which is connected to the power grid or load. When the energy storage system is operating normally, the auxiliary power supply unit directly draws power from the battery to provide auxiliary power supply to the controller, battery management system BMS and energy management system EMS in the energy storage converter PCS. Since the auxiliary power supply unit does not draw power from the power grid, the energy storage system can still obtain stable power supply even if the power grid is powered off (power outage or the energy storage system is off-grid standby). The controller, battery management system BMS and energy management system EMS in the energy storage converter PCS respectively monitor the operating status of each component unit of the energy storage system, and determine the operating status of each component unit. When the operating status meets the preset trigger condition, a stop power supply signal is sent to the auxiliary power supply unit. The wake-up signal of the auxiliary power supply unit comes from the power grid. After the power grid is powered off and then powered on again (or powered on after a power outage), the auxiliary power supply unit will be re-awakened to supply power to the energy storage system, which is convenient for power-on maintenance or system recovery. The energy storage system enables multiple devices in the energy storage system to draw power directly from batteries instead of AC power, thus preventing grid anomalies from affecting normal power supply.

[0039] The energy storage system provided by the present invention enables multiple devices in the energy storage system to directly draw power from the battery, without the need to supply power to the auxiliary power supply through a UPS, thereby reducing the cost of the energy storage system. When the AC power grid is restored, the auxiliary power supply can be automatically awakened for power supply, without the need for on-site maintenance, thereby reducing the difficulty of on-site maintenance. In addition, the energy storage system has a software-controlled auxiliary power supply shutdown function, and after the auxiliary power supply is shut down, it no longer draws power from the battery, thereby having a function of preventing battery power loss.

[0040] In an optional embodiment, if Figure 4As shown, the auxiliary power supply unit includes a first auxiliary power supply. One end of the first auxiliary power supply is connected to the battery, and the other end of the first auxiliary power supply is respectively connected to the battery management system BMS and the energy management system EMS. When the energy storage system operates normally or the power grid is powered off, the first auxiliary power supply directly draws power from the battery to provide auxiliary power to the battery management system BMS and the energy management system EMS. When the battery management system BMS or the energy management system EMS detects fault information, the energy management system EMS sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery. When the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

[0041] Specifically, the first auxiliary power supply supports power supply to the battery management system BMS, the energy management system EMS, and other low-voltage devices in the energy storage system (such as LED lights and buzzers). The first auxiliary power supply receives a stop power supply signal sent by the battery management system BMS or the energy management system EMS. When the battery management system BMS monitors and obtains the fault information of the battery, the stop power supply signal is sent to the first auxiliary power supply through the energy management system EMS; when the energy management system EMS monitors and obtains the fault information of each supporting subsystem, the stop power supply signal is directly sent to the first auxiliary power supply. When the first auxiliary power supply receives the stop power supply signal, the auxiliary power supply will no longer draw power from the battery and maintain the stop power supply state to prevent the battery from being discharged and damaged. The first auxiliary power supply can also receive a wake-up signal. After the wake-up signal arrives, the first auxiliary power supply will restart and maintain operation.

[0042] In an optional embodiment, if Figure 5 As shown, the other end of the first auxiliary power supply is also connected to the controller in the energy storage converter PCS. When the energy storage system operates normally or the power grid is powered off, the first auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller detects fault information, the controller sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery; when the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

[0043] Specifically, the first auxiliary power supply can also support power supply to the battery management system BMS, the energy management system EMS, the controller in the energy storage inverter PCS, and other low-voltage equipment in the energy storage system. The first auxiliary power supply also receives a stop power supply signal sent by the controller. When the controller monitors and obtains the fault information of the energy storage inverter PCS, it sends a stop power supply signal to the first auxiliary power supply. When the first auxiliary power supply receives the stop power supply signal, the auxiliary power supply will no longer draw power from the battery and maintain the stop power supply state to prevent the battery from being discharged and damaged. The first auxiliary power supply can also receive a wake-up signal. After the wake-up signal arrives, the first auxiliary power supply will restart and maintain operation.

[0044] In an optional embodiment, if Figure 6 As shown, the auxiliary power supply unit also includes a second auxiliary power supply, one end of which is connected to the battery, and the other end of which is connected to the controller. When the energy storage system operates normally or the power grid is powered off, the second auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller, battery management system BMS or energy management system EMS detects fault information, the controller sends a stop power supply signal to the second auxiliary power supply, and the second auxiliary power supply stops drawing power from the battery; when the power grid is restored, the second auxiliary power supply restarts according to the wake-up signal of the power grid.

[0045] Specifically, Figure 6 As shown, when the auxiliary power supply unit includes a first auxiliary power supply and a second auxiliary power supply, the first auxiliary power supply only supports powering the battery management system BMS, the energy management system EMS, and other low-voltage devices in the energy storage system. The second auxiliary power supply only supports powering the controller and other devices (such as fans, drives, and communications) in the energy storage inverter PCS. When the controller monitors and obtains fault information, it sends a stop power supply signal to the second auxiliary power supply. After the second auxiliary power supply receives the stop power supply signal, it will no longer draw power from the battery and maintain the stop power supply state to prevent the battery from being discharged and damaged. The second auxiliary power supply can also receive a wake-up signal. After the wake-up signal arrives, the second auxiliary power supply will restart and maintain operation. Among them, the first auxiliary power supply is arranged outside the energy storage inverter PCS, and the second auxiliary power supply is arranged inside the energy storage inverter PCS.

[0046] In an optional embodiment, if Figure 6 As shown, the battery management system BMS and the energy management system EMS, the energy management system EMS and the controller, and the battery management system BMS and the controller are all communicatively connected.

[0047] Specifically, the controller, battery management system BMS, and energy management system EMS in the energy storage converter PCS are connected to each other, and one of them can pass the relevant status information to the other two. Since the controller, battery management system BMS, and energy management system EMS in the energy storage converter PCS communicate with each other, the stop power supply signal can be transmitted and interconnected, that is, any control end can obtain the stop power supply status and information of the entire energy storage system. The first auxiliary power supply and the second auxiliary power supply only need to receive the stop power supply signal sent by any control end to complete the auxiliary power supply shutdown. For example, the stop power supply signal sent by the energy management system EMS to the first auxiliary power supply can directly obtain the stop power supply signal triggered by each subsystem unit for the energy management system EMS, or it can indirectly obtain the stop power supply signal from the battery or PCS system through communication. Similarly, the second auxiliary power supply is the same. Among them, the optional communication lines include 485, CAN status IO, etc.

[0048] In an optional implementation, the first auxiliary power supply and the second auxiliary power supply will stop working immediately after receiving the stop power supply signal, but because the stop signal comes from different control terminals, the first auxiliary power supply and the second auxiliary power supply are not shut down at the same time.

[0049] Specifically, when the controller, battery management system BMS, and energy management system EMS in the energy storage converter PCS obtain the triggering conditions for stopping power supply, in order to prevent misjudgment or complete stable shutdown and status recording, the auxiliary power supply is usually not turned off immediately, and the power supply stop instruction can be delayed to each auxiliary power supply. Therefore, the first auxiliary power supply and the second auxiliary power supply will eventually remain in the shutdown state, but the shutdown time is not at the same time. After receiving the signal to stop power supply, the auxiliary power supply will stop working and maintain the "locked" shutdown state of shutdown, that is, it will not run at no load or start repeatedly, avoiding continuous or intermittent auxiliary power consumption, achieving the purpose of stopping power supply from the battery, and avoiding the expansion of the fault range (battery discharge) before the maintenance personnel arrive; when the power grid is powered on, the auxiliary power supply recognizes the change in the state of the power grid from no power to power, and resumes work. Compared with the existing technology, there is no need for UPS, no trip switch, and the number of auxiliary power supplies is reduced, thereby reducing costs.

[0050] In an optional implementation, the first auxiliary power supply and the second auxiliary power supply are flyback power supplies with isolated outputs.

[0051] Specifically, the first auxiliary power supply and the second auxiliary power supply are both Figure 7 The flyback power supply is shown in Figure 1. Figure 7The flyback power supply shown in the figure receives a response to stop drawing power, maintains the shutdown lock state, and can be awakened externally. The specific process of stopping drawing power and maintaining the lock state is as follows: after any control end of the controller, battery management system BMS, and energy management system EMS in the energy storage converter PCS sends a stop power signal, the secondary side of the isolation optocoupler U2 is turned on, the drive end G of the MOS tube Q2 will be set to a high level, and the MOS tube Q2 will be in the on state. The PWM chip enable pin EN is pulled low; the PWM chip stops PWM; the main power tube Q3 of the flyback circuit will remain in the off state, the auxiliary power supply stops working, the main winding Ns1 supplies power to the low-voltage equipment (including the controller, battery management system BMS, and energy management system EMS), and the auxiliary winding Ns2 supplies power to the PWM chip Vdd. At the same time, since the MOS tube Q2 is turned on, the B pole of the transistor Q1 will be lower than the E pole, and the transistor Q1 will be in the on state; the C pole of the transistor Q1 will be set to a high level, and the MOS tube Q2 will be maintained at a high level through the R5 resistor, and the auxiliary power supply will be in a locked state that is not affected by the power-off state (even if the controller does not send a shutdown signal due to a power outage of the auxiliary power supply, and the secondary side of U2 is in the off state), the MOS tube Q2 will remain turned on, the auxiliary power supply will remain shut down, and no power will be drawn from the battery.

[0052] When the grid is powered on after a power outage (power outage automatically recovers) or the on-site maintenance personnel power on after powering off, the auxiliary power supply will be awakened. The specific awakening process is as follows: after the grid is powered off, the capacitor C1 will be discharged through R9; when the grid is powered on, the capacitor C1 will be charged through the series circuit of R7 and the diode driving the optocoupler U3. There is a pulse current in the charging process, which will make the secondary side of the isolation optocoupler U3 in a conducting state for a certain period of time; the high level previously maintained by the MOS tube Q2 will be set low, and the MOS tube Q2 will be in a closed state. The PWM chip enable pin EN is set high; the PWM chip works again, the auxiliary power supply resumes operation, and the auxiliary power supply outputs power. At the same time, since the MOS tube Q2 is turned off, the B pole of the transistor Q1 will be equal to the E pole, and the transistor Q1 will be in a closed state; the C pole of the transistor Q1 will be pulled down to a low level by R6, and the MOS tube Q2 will be maintained at a low level through the resistor R5, and the auxiliary power supply is in a stable operating state (even if the wake-up circuit only sends a short pulse current for a certain period of time, the secondary side of U3 is in a closed state).

[0053] In an optional embodiment, the energy storage system further includes: a battery monitoring system, a supporting subsystem and an energy storage converter PCS monitoring system. The battery monitoring system is used to monitor the status information of the battery and send the status information to the battery management system BMS. The supporting subsystem sends its own operation information to the energy management system EMS. The energy storage converter PCS monitoring system is used to monitor the operation information of the energy storage converter PCS and send the operation information to the controller.

[0054] Specifically, Figure 6 As shown, the battery monitoring system is composed of voltage sampling circuit, current sampling circuit, temperature sampling circuit and other circuits. The battery management system BMS identifies the battery (including battery cluster, battery pack, battery cell) information through the voltage sampling circuit, current sampling circuit, temperature sampling circuit and other circuits, and can obtain more battery information such as SOC, SOH and so on through related algorithms. The battery management system BMS determines the received status information, and when the status information meets the preset trigger condition, the battery management system BMS sends a stop power supply signal to the auxiliary power unit.

[0055] The supporting subsystem realizes the reliable and stable operation of the energy storage system. The supporting subsystem consists of fire protection system, temperature control system, power distribution system, lighting system, alarm system and other parts. Each supporting subsystem can send its own operating status to the energy management system EMS through communication or dry contact signals. The energy management system EMS determines the received operating information. When the operating information meets the preset trigger conditions, the energy management system EMS sends a stop power supply signal to the auxiliary power supply unit.

[0056] like Figure 6 As shown, the energy storage converter PCS monitoring system is composed of a voltage sampling circuit, a current sampling circuit, a temperature sampling circuit and other circuits. The controller monitors and obtains the PCS operation information of the energy storage converter through the voltage sampling circuit, the current sampling circuit, the temperature sampling circuit and the like. The controller determines the received operation information, and when the operation information meets the preset trigger condition, the controller sends a stop power supply signal to the auxiliary power supply unit.

[0057] In an optional implementation, the preset trigger conditions include: battery abnormality, energy storage system failure, and power grid abnormality.

[0058] Specifically, the controller, battery management system BMS, and energy management system EMS in the energy storage converter PCS monitor the status of each component unit of the energy storage system, and classify the faults through the software of each control end. When the preset trigger conditions are met, a stop power supply signal is sent, and the auxiliary power supply will stop working to prevent the auxiliary power supply from self-consumption or no-load operation, and avoid the expansion of the fault scope before the maintenance personnel arrive. The preset trigger conditions include but are not limited to;

[0059] i. When the battery (including battery cells, battery packs, and battery clusters) detects an abnormal situation that does not allow continued discharge through the battery management system BMS:

[0060] 1. The SOC or voltage is lower than the threshold (if the battery continues to discharge, it will be discharged and damaged);

[0061] 2. The temperature is lower than the minimum operating range (battery discharge is not allowed);

[0062] ii. When the energy management system EMS or energy storage converter PCS identifies that the energy storage system has an irrecoverable fault or the external power grid is abnormal, and is unable to regulate battery charging, and determines that the risk of battery emptying will occur in the long run:

[0063] 1. Unrecoverable faults of the energy storage converter PCS such as insulation abnormality, power conversion unit failure, self-test abnormality, etc.;

[0064] 2. Temperature control system abnormalities, power distribution abnormalities (fuse circuit breaker, long-distance transport AC switch disconnection), controller in the energy storage converter PCS, battery management system BMS, energy management system EMS communication abnormalities, fire or alarm triggering (access control triggering, etc.), and various supporting subsystem abnormalities;

[0065] 3. External power grid abnormality: the battery power is low when operating off-grid but cannot be recharged in the short term; the power grid is damaged by natural disasters and there is a long-term power outage, etc.

[0066] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An energy storage system, characterized in that: The energy storage system includes: an auxiliary power supply unit, a battery management system, an energy management system, an energy storage converter and a battery, wherein: The auxiliary power supply unit is connected to the battery so that the auxiliary power supply draws power from the battery, and the auxiliary power supply unit is respectively connected to the controller in the energy storage converter, the battery management system and the energy management system to supply power to the controller, the battery management system and the energy management system; When the energy storage system operates normally or the power grid is powered off, the auxiliary power supply unit draws power directly from the battery to provide auxiliary power to the controller in the energy storage inverter, the battery management system and the energy management system; when the controller, the battery management system or the energy management system detects fault information, the auxiliary power supply unit stops drawing power from the battery; when the power grid is restored, the auxiliary power supply unit restarts according to the wake-up signal of the power grid.

2. The energy storage system according to claim 1, characterized in that: The auxiliary power supply unit comprises a first auxiliary power supply, one end of the first auxiliary power supply is connected to the battery, and the other end of the first auxiliary power supply is connected to the battery management system and the energy management system respectively; When the energy storage system operates normally or the power grid is powered off, the first auxiliary power source directly draws power from the battery to provide auxiliary power to the battery management system and the energy management system; When the battery management system or the energy management system detects fault information, the energy management system sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery; when the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

3. The energy storage system according to claim 2, characterized in that: The other end of the first auxiliary power supply is also connected to the controller in the energy storage converter; When the energy storage system operates normally or the power grid is powered off, the first auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller detects fault information, the controller sends a stop power supply signal to the first auxiliary power supply, and the first auxiliary power supply stops drawing power from the battery; when the power grid is restored, the first auxiliary power supply restarts according to the wake-up signal of the power grid.

4. The energy storage system according to claim 2, characterized in that: The auxiliary power supply unit further includes a second auxiliary power supply, one end of the second auxiliary power supply is connected to the battery, and the other end of the second auxiliary power supply is connected to the controller; When the energy storage system operates normally or the power grid is powered off, the second auxiliary power supply directly draws power from the battery to provide auxiliary power to the controller; when the controller, the battery management system or the energy management system detects fault information, the controller sends a power-off signal to the second auxiliary power supply, and the second auxiliary power supply stops drawing power from the battery; when the power grid is restored, the second auxiliary power supply restarts according to the wake-up signal of the power grid.

5. The energy storage system according to claim 4, characterized in that: The second auxiliary power supply is arranged in the energy storage converter.

6. The energy storage system according to claim 1, characterized in that: The battery management system is communicatively connected to the energy management system, the energy management system is communicatively connected to the controller, and the battery management system is communicatively connected to the controller.

7. The energy storage system according to claim 4, characterized in that: The first auxiliary power supply and the second auxiliary power supply are flyback power supplies with isolated outputs.

8. The energy storage system according to claim 1, characterized in that: The energy storage system also includes: a battery monitoring system, a supporting subsystem and an energy storage converter monitoring system, wherein: The battery monitoring system is used to monitor the status information of the battery and send the status information to the battery management system; The supporting subsystem sends its own operating information to the energy management system EMS; The energy storage converter monitoring system is used to monitor the operation information of the energy storage converter and send the operation information to the controller.

9. The energy storage system according to claim 8, characterized in that: The battery management system determines the received status information, and when the status information meets a preset trigger condition, the battery management system sends a stop power supply signal to the auxiliary power supply unit; The energy management system determines the received operation information, and when the operation information meets a preset trigger condition, the energy management system sends a stop power supply signal to the auxiliary power supply unit; The controller determines the received operation information, and when the operation information meets a preset trigger condition, the controller sends a stop power supply signal to the auxiliary power supply unit.

10. The energy storage system according to claim 9, characterized in that: The preset trigger conditions include: battery abnormality, energy storage system failure, and power grid abnormality.

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