Energy storage system, control method and energy storage device

Abstract

The invention belongs to the technical field of energy storage systems, and particularly relates to an energy storage system, a control method and an energy storage device. The energy storage system comprises a DC bus; the AC input end of the electric energy management module is connected with an AC charging pile / power grid, and the power transmission end is connected with the DC bus; the first input / output end of the backup power supply is connected with the direct-current bus, and the enabling end is connected with the first auxiliary power transmission end of the electric energy management module through a first switch unit; the input end of the power output module is connected with the direct-current bus, and the output end is connected with an external load; wherein the electric energy management module is in communication connection with the backup power supply and the power output module; by switching the working state of the first switch unit, when the electric quantity of the back-up power supply is higher than a critical value, power is transmitted to the direct current bus through the first input / output end, and when the electric quantity of the back-up power supply is lower than or equal to the critical value, power is supplemented from the direct current bus through the first input / output end.

Description

Technical Field

[0001] The present application belongs to the technical field of energy storage systems, and specifically relates to an energy storage system, a control method, and an energy storage device. Background Art

[0002] As an energy hub in the power system, the energy storage system can achieve demand-side management and power output, and can provide long-term battery life for other power tools during outdoor operations. For example, in the field of garden tools, when the power of nearby garden tools is exhausted, they can be charged through the energy storage system.

[0003] However, most energy storage systems currently operate off-grid, and their internal wiring harnesses are complex and the system losses are high. At the same time, due to limited capacity, the number of loads that can be connected and the total power output are easily restricted. Even if the energy storage system is connected to the grid, it cannot be effectively supplemented, which affects the working efficiency of the energy storage system.

[0004] In addition, the AC output port of a general energy storage system is similar to a socket, has no power limit, and is easily affected by the AC load, which causes the AC load to obtain electrical energy without limit, making it impossible for the DC output port of the energy storage system to supply electricity normally. Summary of the invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a new energy storage system architecture that can operate in grid-connected or off-grid mode, and in grid-connected mode, can provide timely power replenishment according to the amount of electricity, so as to ensure sufficient power output of the system to meet the power requirements of DC loads and AC loads. At the same time, the AC output power is limited to avoid affecting the DC output of the energy storage system.

[0006] To achieve the above-mentioned purpose and other related purposes, the present application provides an energy storage system, comprising: a DC bus; an electric energy management module, comprising an AC input terminal, a transmission terminal, and a first auxiliary transmission terminal, wherein the AC input terminal is used to connect to an AC charging pile / grid, the transmission terminal is connected to the DC bus, and the electric energy management module is used to convert the AC power of the AC charging pile / grid into DC power; a backup power supply, comprising a first input / output terminal, an enable terminal, and a first switch unit, wherein the first input / output terminal is connected to the DC bus, and the enable terminal is connected to the first auxiliary transmission terminal through the first switch unit; a power output module, wherein the input terminal is connected to the DC bus, and the output terminal is used to connect to an external load; wherein the electric energy management module is communicatively connected to the backup power supply and the power output module; by switching the working state of the first switch unit: when the power of the backup power supply is higher than a critical value, power is transmitted to the DC bus through the first input / output terminal, and when the power of the backup power supply is lower than or equal to the critical value, power is supplemented from the DC bus through the first input / output terminal.

[0007] According to a specific embodiment of the present application, the backup power supply includes: an energy storage unit, whose second input / output terminal is connected to the first input / output terminal, and the power of the energy storage unit is used as the power of the backup power supply; a second switch unit, connected in series between the first input / output terminal and the second input / output terminal; a DC / DC converter, whose input terminal is connected to the second input / output terminal; a battery management unit, whose power terminal is respectively connected to the output terminal of the DC / DC converter and the enable terminal; wherein, when the power of the energy storage unit is lower than or equal to a critical value, the battery management unit is used to detect the voltage on the output terminal of the DC / DC converter, and when the voltage is lower than a preset voltage threshold and the first switch unit is in a closed state, control the second switch unit to close, and replenish power to the energy storage unit through the DC bus.

[0008] According to a specific embodiment of the present application, the backup power supply also includes: a third switch unit, which is connected in series to the input end of the DC / DC converter, and the third switch unit serves as a starting switch of the energy storage system, and is not closed at the same time as the first switch unit; wherein the battery management unit is also used to monitor the working state of the third switch unit: when the third switch unit is closed, a start signal is sent to the power management module.

[0009] According to a specific embodiment of the present application, a first diode is connected in series between the output end of the DC / DC converter and the enable end of the backup power supply, and the anode of the first diode is connected to the output end of the DC / DC converter, and the cathode of the first diode is connected to the enable end of the backup power supply; a second diode is connected in series between the first switch unit and the enable end of the backup power supply, and the anode of the second diode is connected to one end of the first switch unit, and the cathode of the second diode is connected to the enable end of the backup power supply.

[0010] According to a specific embodiment of the present application, the battery management unit is connected to the power management module via a digital signal port, and is used to feed back an emergency fault status signal of the backup power supply to the power management module.

[0011] According to a specific embodiment of the present application, the power management module also includes a photovoltaic input terminal connected to the photovoltaic power source, and the power management module is also used to convert the direct current of the photovoltaic power source and output it through the transmission terminal and the first auxiliary transmission terminal.

[0012] According to a specific embodiment of the present application, the power management module also includes: an AC / DC converter, whose input end serves as the AC input end, and the AC / DC converter is used to convert the AC power of the AC charging pile / grid into DC power output; a photovoltaic interface, whose input end serves as the photovoltaic input end, and the photovoltaic interface is used to convert the DC power of the photovoltaic power supply and output it; an energy management unit, which is used to control the operation of the AC / DC converter, the photovoltaic interface, and the power output module, and to communicate and interact with the battery management unit of the backup power supply.

[0013] According to a specific embodiment of the present application, it also includes: a charging pile detection module, which is respectively communicated with the power management module and the AC charging pile, and is used to identify the output power of the AC charging pile; wherein the energy management unit is also used to determine the AC input power of the AC / DC converter based on the maximum allowable current of the AC / DC converter and the maximum output current of the AC charging pile / grid.

[0014] According to a specific embodiment of the present application, an auxiliary power bus is also included; the power management module also includes a second auxiliary power transmission terminal connected to the auxiliary power bus.

[0015] According to a specific embodiment of the present application, the power output module includes: a DC / AC converter, whose input end is connected to the DC bus and whose output end is used to connect to an external AC load; a fourth switch unit, and the enable end of the DC / AC converter is connected to the auxiliary power bus through the fourth switch unit; wherein the power management module is also used to control the fourth switch unit to cut off the AC output of the DC / AC converter when the AC power output by the DC / AC converter exceeds a preset power threshold.

[0016] According to a specific embodiment of the present application, it also includes: a human-computer interaction module, which is communicatively connected to the power management module and is used to display at least one of the power replenishment information of the backup power supply, the charging information of the system and the load, the grid-connected / off-grid information of the system, the fault information of the system, the 4G signal of the system and the GPS signal of the system.

[0017] A control method for an energy storage system comprises: after the system is connected to the grid, judging whether to supply power to a connected load according to the power of a backup power supply: if the power of the backup power supply is higher than a critical value, supplying power to the load according to a preset allocation strategy according to the AC input power of the system and the output power of the backup power supply; if the power of the backup power supply is lower than or equal to the critical value, supplementing power to the backup power supply until the power of the backup power supply exceeds the preset value, and then supplying power to the load according to the preset allocation strategy according to the AC input power of the system and the output power of the backup power supply.

[0018] According to a specific embodiment of the present application, when the system is connected to the grid, the step of determining whether to supply power to the connected load based on the power of the backup power supply includes: identifying the connection status between the system and the AC charging pile / grid, and determining the AC input power of the system: if the system is connected to the AC charging pile, the AC input power of the system is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the AC charging pile; if the system is connected to the grid, the AC input power of the system is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the grid.

[0019] According to a specific embodiment of the present application, the step of supplying power to the load according to the allocation strategy based on the system's AC input power and the output power of the backup power supply includes: calculating the output power of the AC / DC converter in the power management module according to the system's AC input power, and taking the sum of the output power of the AC / DC converter and the output power of the backup power supply as the system's output power; making a judgment based on the system's output power and the AC load request power: if the system's output power is less than the AC load request power, controlling the system to power off; if the system's output power is greater than or equal to the AC load request power, supplying the system's output power to the AC load first, and allocating the remaining system output power to the DC load.

[0020] According to a specific embodiment of the present application, the step of allocating the remaining output power of the system to the DC load includes: judging based on the remaining output power of the system and the power requested by the DC load: if the remaining output power of the system is less than the power requested by the DC load, supplying the remaining output power of the system to the DC load according to the allocation strategy; if the remaining output power of the system is greater than or equal to the power requested by the DC load, and the difference between the output power of the AC / DC converter and the power requested by the AC load is less than or equal to the power requested by the DC load, allocating the remaining output power of the system to each DC load according to the requested output power; if the remaining output power of the system is greater than or equal to the power requested by the DC load, and the difference between the output power of the AC / DC converter and the power requested by the AC load is greater than the power requested by the DC load, allocating the remaining output power of the AC / DC converter to each DC load according to the requested output power, and using the excess output power of the AC / DC converter to charge the backup power supply.

[0021] According to a specific embodiment of the present application, the step of supplying power to the load according to the distribution strategy based on the system's AC input power and the output power of the backup power supply also includes: when the power of the backup power supply is lower than or equal to a critical value, disconnecting the charging circuit between the system and the load, and replenishing the backup power supply.

[0022] According to a specific embodiment of the present application, it also includes: when the system is off the grid, judging whether to supply power to the connected load based on the power level of the backup power supply: if the power level of the backup power supply is higher than a critical value, supplying power to the load according to a preset allocation strategy based on the output power of the backup power supply; if the power level of the backup power supply is lower than or equal to the critical value, the control system is powered off.

[0023] According to a specific embodiment of the present application, the step of supplying power to the load according to a preset allocation strategy based on the output power of the backup power supply includes: making a judgment based on the output power of the backup power supply and the power requested by the AC load: if the output power of the backup power supply is less than the power requested by the AC load, the system is powered off; if the output power of the backup power supply is greater than or equal to the power requested by the AC load, the output power of the backup power supply is preferentially supplied to the AC load, and the remaining output power of the backup power supply is allocated to the DC load.

[0024] According to a specific embodiment of the present application, the step of allocating the remaining output power of the backup power supply to the DC load includes: making a judgment based on the remaining output power of the backup power supply and the power requested by the DC load: if the remaining output power of the backup power supply is less than the power requested by the DC load, then supplying the remaining output power of the backup power supply to the DC load through the DC output module according to the allocation strategy; if the remaining output power of the backup power supply is greater than or equal to the power requested by the DC load, then allocating the remaining output power of the backup power supply to each DC load according to the requested output power.

[0025] According to a specific embodiment of the present application, the step of supplying power to the load according to a preset allocation strategy based on the output power of the backup power supply also includes: when the power level of the backup power supply is lower than or equal to a critical value, disconnecting the charging circuit between the system and the load, and controlling the system to power off.

[0026] According to a specific embodiment of the present application, the step of recharging the backup power supply includes: controlling the first switch unit to close to provide a working voltage and current to the enable end of the backup power supply; sending a recharging confirmation message to the human-computer interaction module based on the recharging signal of the battery management unit in the backup power supply; receiving the recharging confirmation message fed back by the human-computer interaction module, and sending it to the battery management unit.

[0027] According to a specific embodiment of the present application, after the first switch unit is closed, the battery management unit starts and identifies the power level of the backup power supply, and also detects the voltage at the output end of the DC / DC converter in the backup power supply: when the power level of the backup power supply is lower than or equal to the critical value, and the voltage at the output end of the DC / DC converter in the backup power supply is lower than a preset voltage threshold, the battery management unit outputs a power replenishment signal.

[0028] According to a specific embodiment of the present application, after the battery management unit receives the power replenishment confirmation information fed back by the human-computer interaction module: if the power replenishment confirmation information confirms power replenishment, the battery management unit controls the second switch unit in the backup power supply to close for power replenishment until the power of the backup power supply exceeds a preset value, and sends a power replenishment completion signal to the power management module after the power replenishment is completed; if the power replenishment confirmation information confirms no power replenishment, the battery management unit controls the first switch unit to disconnect.

[0029] A control method for an energy storage system comprises: when the system is off-grid, judging whether to supply power to a connected load according to the power level of a backup power supply; if the power level of the backup power supply is higher than a critical value, supplying power to the load according to a preset allocation strategy based on the output power of the backup power supply; if the power level of the backup power supply is lower than or equal to the critical value, powering off the control system.

[0030] A power storage device comprises: a body, and a DC bus, an electric energy management module, a backup power supply and a power output module arranged on the body; the electric energy management module comprises an AC input terminal, a transmission terminal and a first auxiliary transmission terminal, the AC input terminal is used to connect to an AC charging pile / grid, the transmission terminal is connected to the DC bus, and the electric energy management module is used to convert the AC power of the AC charging pile / grid into DC power; the backup power supply comprises a first input / output terminal, an enable terminal and a first switch unit, the first input / output terminal is connected to the DC bus, and the enable terminal is connected to the first auxiliary transmission terminal through the first switch unit; the input terminal of the power output module is connected to the DC bus, and the output terminal is used to connect to an external load; wherein the electric energy management module is communicatively connected to the backup power supply and the power output module; by switching the working state of the first switch unit: when the power of the backup power supply is higher than a critical value, power is transmitted to the DC bus through the first input / output terminal, and when the power of the backup power supply is lower than or equal to the critical value, power is supplemented from the DC bus through the first input / output terminal.

[0031] The present application provides an energy storage system that adopts a new energy storage system architecture, which can freely choose to operate in grid-connected or off-grid mode to deliver electric energy to the load. At the same time, the backup power supply in the system can be replenished in time when the system is connected to the grid to avoid insufficient power when the system is off-grid and cannot work normally. Furthermore, the system assembly has a DC bus, an auxiliary power bus, and a communication bus, which simplifies the line structure, greatly improves the system's working efficiency, and reduces losses. In addition, the system limits the AC output power to avoid unlimited demands from the AC load, so that the system can reasonably allocate available power according to the DC load and the AC load.

[0032] The interaction between the energy storage system of the present application and the user is more intelligent, and can effectively display different information of the system, respond to different states of the system, and facilitate user operation.

[0033] Therefore, the energy storage system of the present application has good stability and high reliability, and can realize different power transmission modes according to corresponding control strategies, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a specific embodiment of an energy storage system provided in this application;

[0035] Figure 2 A circuit diagram of a specific embodiment of an electric energy management module in an energy storage system provided by the present application;

[0036] Figure 3 A circuit diagram of a specific embodiment of a backup power supply in an energy storage system provided by the present application;

[0037] Figure 4 A circuit diagram of a specific embodiment of a power output module in an energy storage system provided by the present application;

[0038] Figure 5 A circuit diagram of a specific embodiment of a human-computer interaction module in an energy storage system provided by this application;

[0039] Figure 6 A schematic diagram of a specific embodiment of a control method for an energy storage system provided in the present application;

[0040] Figure 7 A first logic diagram of a specific embodiment of a control method for an energy storage system provided in the present application;

[0041] Figure 8 A second logic diagram of a specific embodiment of a control method for an energy storage system provided in the present application;

[0042] Fig. 9 A third logic diagram of a specific embodiment of a control method for an energy storage system provided by the present application;

[0043] Fig.10 A first logic diagram of a specific embodiment of a power replenishment strategy in a control method of an energy storage system provided in the present application;

[0044] Fig.11 A second logic diagram of a specific embodiment of a power replenishment strategy in a control method for an energy storage system provided in the present application;

[0045] Fig.12A flowchart of a specific embodiment of a control method for an energy storage system provided in the present application. DETAILED DESCRIPTION

[0046] The following describes the implementation of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0047] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner, and therefore the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] First of all, it should be noted that in order to enable people in this technical field to better understand the present application scheme, some relevant introduction to the technical background related to this application is given.

[0049] Grid connection refers to the act of an independent power generation system or a small power system being electrically connected to an adjacent power system to exchange power. For example, the act of an energy storage system being connected to the grid to obtain AC input power can be called grid connection.

[0050] Off-grid refers to the behavior of an independent power generation system or a small power system operating independently without connecting to other power systems to exchange power. For example, an independent photovoltaic power generation system or an independent energy storage system transmits power to the outside world.

[0051] See also Figure 1 As shown, this embodiment provides an energy storage system, including a DC bus 10 , an energy management module 20 , a backup power supply 30 and a power output module 40 .

[0052] The power management module 20 serves as the master control module of the energy storage system, which is respectively connected to the backup power supply 30 and the power output module in communication. The power management module 20 includes an AC input terminal, a transmission terminal and a first auxiliary transmission terminal 1#; the AC input terminal is used to connect to the AC charging pile / grid, and the transmission terminal is connected to the DC bus 10. The power management module 20 is used to convert the AC power input from the AC charging pile / grid into DC power, and transmit it to the DC bus 10 through the transmission terminal. At the same time, the power management module 20 can also supply power to the enable terminal of the backup power supply 30 through the first auxiliary transmission terminal 1#, so that the battery management unit 35 of the backup power supply 30 can work.

[0053] The backup power supply 30 is a switchable module, including a first input / output terminal, an enable terminal and a first switch unit 31. The first input / output terminal is connected to the DC bus 10, and the backup power supply 30 can transmit power to the DC bus 10 or supplement power from the DC bus 10 through the first input / output terminal. The enable terminal is connected to the first auxiliary power transmission terminal 1# of the power management module 20 through the first switch unit 31, and by switching the working state of the first switch unit 31, when the power of the backup power supply 30 is higher than the critical value, the power is transmitted to the DC bus 10 through the first input / output terminal, and when the power of the backup power supply 30 is lower than or equal to the critical value, the power is supplemented from the DC bus 10 through the first input / output terminal.

[0054] The input end of the power output module 40 is mounted on the DC bus 10, and the output end of the power output module 40 is connected to an external load. The power output module 40 can obtain available power from the DC bus 10 according to the power demand of the load and distribute it to the load.

[0055] In one embodiment, the energy storage system further includes an auxiliary power bus 50, which is used to provide working power to the power output module 40, the charging pile detection module 60, the human-computer interaction module 70 and other module units to ensure that the corresponding modules of the system can work normally. The power management module 20 also includes a second auxiliary power transmission terminal connected to the auxiliary power bus 50; the backup power supply 30 may also be provided with a third auxiliary power transmission terminal connected to the auxiliary power bus 50, so that power can be output to the auxiliary power bus 50 through the power management module 20 or the backup power supply 30.

[0056] Specifically, in actual applications, when the system is connected to the grid, the power management module 20 transmits power to the auxiliary power bus 50 through its second auxiliary power transmission terminal 2# to maintain the normal operation of other module units of the system; the power of the backup power supply 30 can be used to power the load, without outputting power to the auxiliary power bus 50. When the system is off-grid, it is necessary to rely on the backup power supply 30 to transmit power to the auxiliary power bus 50 through its third auxiliary power transmission terminal, and then use the remaining power to transmit power to the DC bus 10 to supply the load. By reasonably allocating the output power of the power management module 20 and the output power of the backup power supply 30, the system can be powered on and operate normally regardless of whether it is connected to the grid or off-grid.

[0057] In this embodiment, the energy storage system is used to transmit electric energy by setting a DC bus 10 and an auxiliary power bus 50. The module units in the system can be directly mounted on the DC bus 10 and the auxiliary power bus 50. The line connection method is simpler, the wiring harness impedance is correspondingly reduced, the system loss is also improved, and the power conversion efficiency is greatly improved.

[0058] like Figure 2As shown, the power management module 20 is an integrated component, including an AC / DC converter, a photovoltaic interface and an energy management unit, and the energy management unit is connected to the AC / DC converter and the photovoltaic interface.

[0059] The input end of the AC / DC converter serves as the AC input end of the power management module 20, and is connected to the AC charging pile / grid, and is used to convert the AC power of the AC charging pile / grid into DC power and then output it through the transmission end of the power management module 20, the first auxiliary transmission end 1# and the second auxiliary transmission end 2#.

[0060] The photovoltaic interface, the input end serves as the photovoltaic input end PV+ / PV- of the power management module 20, is used to connect to the photovoltaic power source, convert the direct current of the photovoltaic power source, and output it through the transmission end of the power management module 20, the first auxiliary transmission end 1# and the second auxiliary transmission end 2#.

[0061] When the system is connected to the grid, the AC input power from the external charging pile or the grid can be used to maintain the normal operation of the system, and the output power of the photovoltaic interface can be directly transmitted to the DC bus 10 as supplementary power to supply the load. When the system is off-grid, the photovoltaic interface will preferentially transmit the converted DC power to the auxiliary power bus 50 through the second auxiliary transmission terminal 2#, and then transmit the remaining power to the DC bus 10 to cooperate with the backup power supply 30 to supply power to the load.

[0062] The energy management unit, namely the energy management system EMS (Energy Management System), serves as the control unit of the energy management module 20, and is respectively connected to the AC / DC converter and the photovoltaic interface, and is also respectively communicated with other module units in the system, and is used to control the operation of the AC / DC converter, the photovoltaic interface, the power output module 40, and communicate and interact with the battery management unit 35 of the backup power supply 30.

[0063] like Figure 2 As shown, in one embodiment, since the power required for starting the battery management unit 35 is relatively large, while the power required for maintaining other module units in the system is relatively small, two auxiliary power transmission terminals, namely the first auxiliary power transmission terminal 1# and the second auxiliary power transmission terminal 2#, are provided on the power management module 20, and the first auxiliary power transmission terminal 1# is used to provide working power to the battery management unit 35 of the backup power supply 30, and the second auxiliary power transmission terminal 2# is used to provide working power to other module units mounted on the auxiliary power bus 50.

[0064] Of course, the first auxiliary power transmission terminal 1# and the second auxiliary power transmission terminal 2# of the power management module 20 can also be integrated into one port, directly connected to the auxiliary power bus 50, and the battery management unit 35 of the backup power supply 30 can obtain the voltage and current required for normal operation from the auxiliary power bus 50.

[0065] like Figure 3 As shown, in one embodiment, the backup power supply 30 further includes an energy storage unit 32 , a second switch unit 33 , a DC / DC converter 34 and a battery management unit 35 .

[0066] Among them, the first switch unit 31 is used as a supplementary power switch, which can be a mechanical switch or a soft switch, and is connected in series between the enable end of the backup power supply 30 and the first auxiliary power transmission end 1# of the power management module 20; the energy storage unit 32 can be a battery pack for storing electric energy, and the second input / output end of the energy storage unit 32 is connected to the first input / output end of the backup power supply 30, wherein the power of the energy storage unit is also the power of the backup power supply; the second switch unit 33 is connected in series between the second input / output end of the energy storage unit 32 and the first input / output end of the backup power supply 30, and is used to allow Or prohibit the energy storage unit 32 from transmitting power to the DC bus 10, or draw power from the DC bus; the DC / DC converter 34, as a DC conversion device inside the backup power supply 30, can adjust the electric energy of the energy storage unit 32 and supply it to the battery management unit 35, the input end of the DC / DC converter 34 is connected to the second input / output end of the energy storage unit 32, and the output end is connected to the power supply end of the battery management unit 35, and the power supply end of the battery management unit 35 is also connected to the enable end of the backup power supply 30; the battery management unit 35, that is, the battery management system BMS (Battery Management System, BMS), is used to control the operation of the first switch unit 31, the second switch unit 33, and the DC / DC converter 34, and is also used to interact with the power management module 20 in the power management module 20, transmit status information, etc.

[0067] When the power level of the energy storage unit 32 is lower than or equal to the critical value, the battery management unit 35 detects the voltage at the output end of the DC / DC converter 34, and when the output end voltage of the DC / DC converter 34 is lower than the preset voltage threshold and the first switch unit 31 is in a closed state, controls the second switch unit 33 to close, and replenishes power for the energy storage unit 32 through the DC bus 10.

[0068] In order to prevent the first switch unit 31 from mistakenly triggering the power replenishment, it can be stipulated that the battery management unit 35 will only send a power replenishment signal to the power management module 20 when the power level of the energy storage unit 32 is lower than or equal to the critical value and the voltage at the output end of the DC / DC converter 34 is lower than the voltage threshold. After receiving the power replenishment signal, the power management module 20 further confirms whether to replenish power through the human-computer interaction module 70 by the user, and feeds back the user's confirmation information to the battery management unit 35.

[0069] When the user confirms to replenish the power, the battery management unit 35 first controls the pre-charging unit 37 to work, and then controls the second switch unit 33 to close, so that the energy storage unit 32 obtains electric energy from the DC bus 100 for replenishing the power; when the user confirms not to replenish the power, the battery management unit 35 can disconnect the first switch unit 31, or send a signal to the power management module 20, and the power management module 20 reminds the user to manually disconnect the first switch unit 31 through the human-computer interaction module 70.

[0070] like Figure 3 As shown, in one embodiment, the backup power supply 30 also includes a third switch unit 36, which is connected in series to the input end of the DC / DC converter 34 and is not closed at the same time as the first switch unit 31, that is, the first switch unit 31 and the third switch unit 36 ​​are in a linkage state. The power supply source of the battery management unit 35 can be switched through the linkage between the first switch unit 31 and the third switch unit 36. When the third switch unit 36 ​​is closed, the battery management unit 35 is powered by the energy storage unit 32. When the first switch unit 31 is closed, the battery management unit 35 is powered by the first auxiliary power transmission terminal 1# of the power management module 20.

[0071] The third switch unit 36 ​​also serves as a starting switch for the energy storage system. The battery management unit 35 can monitor the working status of the third switch unit 36: when the third switch unit 36 ​​is closed, a starting signal is sent to the power management module 20. The power management module 20 transmits power to the auxiliary power bus 50 through the second auxiliary power transmission terminal 2# according to the starting signal, and controls the power-on operation of each module unit in the energy storage system.

[0072] It should be noted that the first switch unit 31 and the third switch unit 36 ​​can be manual switch buttons or electric control buttons, and can be specifically configured according to actual needs.

[0073] like Figure 3 As shown, in one embodiment, the backup power supply 30 also includes a pre-charging unit 37, which is connected in parallel at both ends of the second switch unit 33, and is used to pre-charge the battery cell 32 before charging the battery cell 32 to ensure the stability and safety of the energy storage unit 32 when charging.

[0074] It should be noted that the backup power supply 30 may also include an insulation detection unit, a leakage detection unit, a heating unit, etc., which are used to assist the backup power supply 30 to work normally.

[0075] In one embodiment, the energy storage system further includes a charging pile detection module 60, namely, an EVCC module. When the power management module 20 is connected to the AC charging pile, the communication port of the charging pile detection module 60 is also connected to the CP interface and the PP interface of the AC charging pile respectively, and communicates and interacts with the AC charging pile to identify the connection status between the power management module 20 and the AC charging pile. If an abnormal plugging of the AC charging pile is detected, the charging pile detection module 60 will promptly feed back the information to the power management module 20, and the power management module 20 will alert the user through the human-computer interaction module 70, so that the user can reconnect the AC charging pile.

[0076] After detecting that the AC charging pile is plugged in normally, the charging pile detection module 60 obtains the maximum output current of the AC charging pile and feeds it back to the energy management unit of the power management module 20 through the CAN bus. The energy management unit limits the AC input power of the AC / DC converter according to the maximum output current of the AC charging pile and the maximum allowable current of the AC / DC converter, so that the current value corresponding to the maximum AC input power of the AC / DC converter is the minimum value between the maximum output current of the AC charging pile and the maximum allowable current of the AC / DC converter.

[0077] Similarly, when the power management module 20 is connected to the power grid, the energy management unit limits the AC input power of the AC / DC converter according to the maximum output current of the power grid and the maximum allowable current of the AC / DC converter, so that the current value corresponding to the maximum AC input power of the AC / DC converter is the minimum value between the maximum output current of the power grid and the maximum allowable current of the AC / DC converter, and then allows the power input of the power grid to effectively protect the safety of the system.

[0078] In one embodiment, if Figure 5 As shown, the energy storage system also includes a human-computer interaction module 70, which can adopt an HMI human-computer interface and can be set according to actual needs to realize intelligent interaction between the system and the user. For example, it can display the power supply information such as the amount of electricity and available power of the backup power supply 30, the charging information of the system and the load, the grid-connected and off-grid status of the system, the fault information of the system, the geographical location, the 3G signal of the system, the 4G signal of the system, the 5G signal of the system, and one or more of the GPS signals of the system. In one embodiment, the energy storage system also includes a communication bus, including a CAN-H bus and a CAN-L bus, using the CAN bus communication protocol, the power management module 20, the backup power supply 30, the power output module 40, the charging pile detection module 60, and the human-computer interaction module 70 are connected through the communication bus to realize communication interaction.

[0079] In one embodiment, a long-distance communication module or a short-distance wireless communication module may be integrated in the human-computer interaction module 70. The long-distance communication module may be, for example, a 3G module, a 4G module, a 5G module, a 6G module, a GPS module or other wireless module; the short-distance wireless communication module may be, for example, a Bluetooth module, a WiFi module, an NFC or other wireless module. Figure 3 As shown, in one embodiment, the energy storage system is further provided with anti-backflow diodes, namely, a first diode D1 and a second diode D2. Among them, the anode of the first diode D1 is connected to the output end of the DC / DC converter 34, and the cathode is connected to the enable end of the backup power supply 30. The unidirectional conduction of the diode is used to prevent the 12V power input through the enable end from backflowing to the output end of the DC / DC converter 34; the anode of the second diode D2 is connected to one end of the first switch unit 31, and its cathode is connected to the enable end of the backup power supply 30. The unidirectional conduction of the diode is used to prevent the 12V power output by the DC / DC converter 34 from backflowing to the line where the first switch unit 31 is located, which effectively ensures the stability and safety of the energy storage system.

[0080] like Figure 2 and Figure 3 As shown, the power management module 20 and the backup power supply 30 communicate through the CAN bus, but the CAN communication time is relatively long. When an emergency failure occurs in the backup power supply 30, the power management module 20 cannot receive the signal sent by the backup power supply 30 in time, so that the power management module 20 cannot respond in time. Based on this, the digital signal terminal DO of the backup power supply 30 is connected to the digital signal terminal DI of the power management module 20 for physical signal communication, which is used to transmit the emergency failure signal to the power management module 20 through the digital signal terminal DI / DO when an emergency failure occurs in the backup power supply 30, and the safety of the energy storage system is ensured by using the characteristics of the fast speed and high reliability of the digital signal terminal DI / DO.

[0081] like Figure 4 As shown, in one embodiment, the power output module 40 is used to convert the available power on the DC bus 10 into the voltage and current required by the load. Since there are AC loads and DC loads, the power output module 40 can be divided into a DC output unit 43 and an AC output unit 41 to correspond to the DC load and the AC load.

[0082] like Figure 4 As shown, the DC output unit 43 may include multiple DC / DC converters, and the output ends of the DC / DC converters are used to connect to various DC loads respectively; the AC output unit 41 may include one or more DC / AC converters, and the output ends of the DC / AC converters are used to connect to AC loads.

[0083] Specifically, in practical applications, the output end of the DC / DC converter in the DC output unit 43 can be formed as a plug port, which can be used to connect DC loads such as electric garden tools, and the DC / DC converter and the DC load can also communicate and interact through the CAN bus, so as to obtain the power demand of the DC load and the charging information of the DC load, and feed it back to the power management module 20. The power management module 20 can display the charging status of the DC load according to the charging information of the DC load and through the human-computer interaction module 70.

[0084] Furthermore, the output end of the DC / DC converter in the DC output unit 43 can also be formed as a charging gun, which can be used to connect a DC load such as an electric vehicle having a charging gun interface adapted to the charging gun. Therefore, the output end of the DC / DC converter can also integrate multiple wiring harness interfaces such as a communication interface, a power supply interface, and an auxiliary power supply interface. Similarly, the DC / DC converter can obtain the power demand of the DC load and the charging information of the DC load according to the communication interface, and feed it back to the power management module 20.

[0085] It should be noted that the output end of the DC / DC converter in the DC output unit is usually equipped with a relay for disconnecting the DC load, and the DC / DC converter is also used to detect the output voltage and current, and timely feed back to the power management module 20, which uniformly dispatches the available power according to the control strategy.

[0086] In addition, the output end of the DC / AC converter in the AC output unit 41 can be formed as a socket for connecting an AC load. It should be added here that in the energy storage system, the AC output is generally not limited in power and has no disconnecting device. Therefore, the AC output of the energy storage system is easily affected by the AC load, so that the AC load can obtain electrical energy without restriction, resulting in the available power of the energy storage system being insufficient to support the needs of the DC load.

[0087] Based on this, Figure 4As shown, the power output module 40 also includes a fourth switch unit 42, and one end of the fourth switch unit 42 is connected to the auxiliary power bus 50, and the other end is connected to the enable end of the DC / AC converter in the AC output unit 41. Specifically, the fourth switch unit 42 can be connected to the MOS tube / IGBT tube of the DC / AC converter, or connected to the output end of the DC / AC converter through a MOS tube / IGBT tube. When the fourth switch unit 42 is closed, the high-level signal on the auxiliary power bus 50 turns off the MOS tube / IGBT tube, cuts off the internal loop of the DC / AC converter, and thus disconnects the AC output of the system. By setting the fourth switch unit 42, when the AC load is not powered, the power supply line between the auxiliary power bus and the AC output unit 41 can be cut off, so that the AC power supply end is in a non-powered state, eliminating the safety hazards caused by the AC power supply end being powered, and also making the AC output unit 41 not powering the AC load, the loss is zero, reducing energy consumption, and playing a role in saving energy.

[0088] Therefore, the DC / AC converter can also be used to detect the output voltage and current, and timely feed back to the power management module 20. When the AC output power of the DC / AC converter exceeds the preset power threshold, the power management module 20 controls the fourth switch unit 42 to close to cut off the AC output. At the same time, the power threshold of the AC output can be limited, and the difference between the available power on the DC bus 10 and the power threshold for limiting the AC output is used as the power that can be allocated to the DC load, thereby simplifying the calculation method of the available power allocation.

[0089] It should be noted that the energy storage system in this embodiment can be fixed or moved. When the system is connected to the grid, it is fixed relative to the grid or the AC charging pile. When the system is off-grid, the energy storage system can be moved to any location, specifically according to the location of the load to be charged, so as to replenish the load with electric energy in time.

[0090] In one embodiment, the energy storage system also includes an emergency stop module, which is connected to the power management module 20 and the power output module 40 respectively. When the emergency stop module is started, the power output module 40 is disconnected from the load within the first preset time to avoid harm to the user. At the same time, after the power output module 40 is disconnected from the load, a corresponding signal is fed back to the power management module 20. After receiving the signal fed back by the power output module 40, the power management module 20 controls the backup power supply 30 to stop transmitting power to the DC bus, and stops transmitting power to the DC bus itself, and disconnects from the AC charging pile / grid. Among them, if the power management module 20 does not receive the signal fed back by the power output module 40 within the second preset time, it will also control itself and the backup power supply 30 to stop working accordingly. The first preset time is usually 50ms-150ms, preferably 100ms, and the second preset time is usually 2s-5s, preferably 3s-4s.

[0091] In addition, the emergency stop module can be a mechanical switch button set on the power output of the system. When the user manually starts it, the above operation is completed immediately, thereby ensuring the safety of the system and the user.

[0092] It should be noted that the energy storage system of the present application, whether in grid-connected operation or off-grid operation, when the power of the backup power supply 30 is lower than or equal to the critical value, the system will stop working and disconnect the load. Among them, when the system is in grid-connected operation, if the power of the backup power supply 30 is lower than or equal to the critical value, the backup power supply 30 can be supplemented according to the AC input power of the AC charging pile or the power grid, and after the backup power supply 30 is supplemented, it can continue to supply power to the load.

[0093] In one application scenario, when the load connection system obtains electric energy, the third switch unit 36 ​​can be closed to start the energy storage system. When the third switch unit 36 ​​is closed, the energy storage unit 32 can supply power to the battery management unit 35 through the DC / DC converter 34. The battery management unit 35 starts normally, and detects the working state of the third switch unit 36, and sends a start signal to the power management module 20 through the CAN bus. The power management module 20 sends power to the auxiliary power bus 50 through the second auxiliary power transmission terminal 2# according to the start signal, and controls the power-on operation of each module unit in the energy storage system. At the same time, the battery management unit 35 also controls the second switch unit 33 to close, and the energy storage unit 32 transmits electric energy to the DC bus 10 through the first input / output terminal of the backup power supply 30, and the power management module 20 controls the power output module 40 to distribute the available power on the DC bus 10 to the load.

[0094] As the system continues to deliver electric energy to the load, the amount of electricity in the energy storage unit 32 is gradually decreasing. When the amount of electricity in the energy storage unit 32 is lower than or equal to the critical value, and the system is connected to the grid, the first switch unit 31 can be closed to supplement the energy storage unit 32. After the first switch unit 31 is closed, the power supply of the battery management unit 35 is switched from the energy storage unit 32 to the power management module 20. After the first switch unit 31 is closed, the power management module 20 can output a 12V power supply to the enable end of the backup power supply 30 through the first auxiliary power transmission terminal 1# to supply power to the battery management unit 35, so as to avoid the energy storage unit 32 being unable to supply power to the battery management unit 35 when switching to charging, causing the battery management unit 35 to stop working and unable to complete the power supplement operation. It should be noted that the first switch unit 31 can be closed manually, or the first switch unit 31 can be closed by controlling the battery management unit 35.

[0095] In another application scenario, when the energy storage system has not been used for a long time and the backup power supply 30 is depleted, the system can be connected to an AC charging station or a power grid to enable the system to operate in parallel with the grid, and the first switch unit 31 can be closed to start the battery management unit 35 so that subsequent power replenishment operations can be performed.

[0096] In summary, the energy storage system of the present application is a new type of energy storage system architecture, which can freely choose to operate in grid-connected or off-grid mode to deliver electrical energy to the load. At the same time, the backup power supply in the system can be replenished in time when the system is connected to the grid to avoid insufficient power when the system is off-grid and cannot work normally. Furthermore, the system assembly has a DC bus, an auxiliary power bus, and a communication bus, which simplifies the line structure, greatly improves the system's work efficiency, and reduces losses. In addition, the system limits the AC output power to avoid unlimited demands from the AC load, so that the system can reasonably allocate available power according to the DC load and the AC load.

[0097] The interaction between the energy storage system of the present application and the user is more intelligent, and can effectively display different information of the system, respond to different states of the system, and facilitate user operation.

[0098] Therefore, the energy storage system of the present application has good stability and high reliability, and can realize different power transmission modes according to corresponding control strategies, which is of great significance.

[0099] See also Figure 6 As shown, the present application also provides a control method for an energy storage system, comprising:

[0100] Step S10: After the system is connected to the grid, it is determined whether to supply power to the connected load according to the power of the backup power supply (SOC):

[0101] Step S20: If the power of the backup power supply is higher than the critical value, the load is supplied with power according to a preset allocation strategy based on the system's AC input power and the output power of the backup power supply.

[0102] If the power of the backup power supply is lower than or equal to the critical value, the backup power supply is supplemented until the power of the backup power supply exceeds the preset value, and then the load is powered according to the preset allocation strategy based on the system's AC input power and the output power of the backup power supply.

[0103] Specifically, Figure 7 , 8 As shown, when the system start switch is closed, the system is powered on and starts to operate normally. The power management module obtains the output power of the backup power supply and the load request power by interacting with the backup power supply and the power output module.

[0104] Next, the system operation mode is identified as grid-connected or off-grid, and when the system is grid-connected, it is determined whether to supply power to the connected load based on the power of the backup power supply.

[0105] Among them, when the system is connected to the grid, the power management module identifies that the system is connected to the AC charging pile or the grid, and limits the system's AC input power. If the system is connected to the AC charging pile, the system's AC input power is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the AC charging pile. If the system is connected to the grid, the system's AC input power is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the grid.

[0106] In actual applications, when the system is connected to an AC charging pile, the charging pile detection module will identify the plug-in status of the AC charging pile; when the plug-in of the AC charging pile is normal, the charging pile detection module communicates and interacts with the AC charging pile to obtain the maximum output current of the AC charging pile, and feeds it back to the power management module. When the plug-in of the AC charging pile is abnormal, the charging pile detection module feeds back the corresponding signal to the power management module, and the power management module promptly reminds the user to reconnect or detect whether the AC charging pile is faulty through the human-computer interaction module. In addition, when the system has completed charging the load, the power management module can disconnect the power transmission circuit from the AC charging pile through the charging pile detection module, and then remind the user to disconnect the system from the AC charging pile.

[0107] It should be noted that when the system is connected to the grid, in order to meet the power demand of the load to the greatest extent, the output power of the AC / DC converter in the power management module is calculated from the AC input power of the system, and the sum of the calculated output power of the AC / DC converter and the output power of the backup power supply is used as the output power of the system, that is, the available power on the DC bus. Therefore, when the power of the backup power supply is lower than or equal to the critical value, it is immediately recharged, and the connection between the power output module and the load is cut off at this time. After the backup power supply is recharged, the load will continue to be powered. At the same time, keeping the power of the backup power supply greater than the critical value can also effectively avoid the problem of insufficient power when the system is off-grid.

[0108] In addition, in this embodiment, when the system supplies power to the load, it gives priority to meeting the needs of the AC load, and then distributes the remaining available power to each DC load. Without departing from the spirit of this application, the modifications and embellishments made to the embodiments of this application by those skilled in the art still fall within the scope of the invention patent application of this application.

[0109] Therefore, when the power of the backup power supply is higher than the critical value, the system output power and the AC load request power are used to determine:

[0110] If the system output power is less than the AC load request power, the control system is powered off.

[0111] If the system output power is greater than or equal to the AC load request power, the system output power is supplied to the AC load first, and the remaining system output power is allocated to the DC load.

[0112] When allocating the remaining output power of the system to the DC load, it is necessary to determine whether the remaining output power of the system can meet the needs of all DC loads. If the remaining output power of the system is less than the requested power of the DC load, the remaining output power of the system is supplied to the DC load according to the preset allocation strategy. If the remaining output power of the system is greater than or equal to the requested power of the DC load, the remaining output power of the system is allocated according to the needs of each DC load.

[0113] Specifically, in the application, for example, it can be allocated according to the power weight required by the DC load. Assuming that the remaining output power of the system is 10KW, the power required by the first DC load is 6KW, the power required by the second DC load is 8KW, and the power required by the third DC load is 6KW. Therefore, the power actually obtained by the first DC load is 3KW, the power actually obtained by the second DC load is 4KW, and the power actually obtained by the third DC load is 3KW. Alternatively, it can be allocated according to the priority of the DC load, for example, the first DC load is transmitted first, and after the first DC load is transmitted, the second DC load is transmitted, and so on.

[0114] It should be noted that the allocation strategy includes but is not limited to the above-mentioned methods. Therefore, the selection of a suitable allocation strategy can be determined according to actual needs to meet the load requirements.

[0115] In one embodiment, if the remaining output power of the system is greater than or equal to the DC load request power, the output power of the AC / DC converter is further detected. When the output power of the AC / DC converter can meet the needs of all loads, that is, the difference between the output power of the AC / DC converter and the AC load request power is greater than the DC load request power, then the excess output power of the AC / DC converter can be used to charge the backup power supply until the power of the backup power supply reaches 100%. When the output power of the AC / DC converter cannot meet the needs of all loads, that is, the difference between the output power of the AC / DC converter and the AC load request power is less than or equal to the DC load request power, the output power of the AC / DC converter and the output power of the backup power supply are jointly delivered to the DC load to meet the needs of the DC load.

[0116] At the same time, when the output power of the backup power supply is supplied to the load, the power of the backup power supply will also decrease. When its power is lower than or equal to the critical value, the charging circuit between the system and the load is disconnected, and the backup power supply is recharged. After the recharge is completed, the charging circuit between the system and the load is reconnected to continue to supply power to the load.

[0117] When the system is off-grid, there is no external power input. Therefore, when the power of the backup power supply is lower than or equal to the critical value, the system can only stop working. Specifically, when the system is off-grid, it determines whether to supply power to the connected load based on the power of the backup power supply: if the power of the backup power supply is higher than the critical value, the load is supplied with power according to the preset allocation strategy based on the output power of the backup power supply. If the power of the backup power supply is lower than or equal to the critical value, the control system is powered off.

[0118] like Figure 7 , 9 As shown in the figure, when the power of the backup power supply is higher than the critical value, the output power of the backup power supply is the output power of the system, and the judgment is made based on the output power of the backup power supply and the AC load request power:

[0119] If the output power of the backup power supply is less than the power requested by the AC load, the control system is powered off.

[0120] If the output power of the backup power supply is greater than or equal to the requested power of the AC load, the output power of the backup power supply is preferentially supplied to the AC load, and the remaining output power of the backup power supply is allocated to the DC load.

[0121] Among them, see whether the remaining output power of the backup power supply can meet the needs of all DC loads. Similarly, if the remaining output power of the backup power supply is less than the requested power of the DC load, the remaining output power of the backup power supply is supplied to the DC load according to the allocation strategy. If the remaining output power of the backup power supply is greater than or equal to the requested power of the DC load, the remaining output power of the backup power supply is allocated according to the needs of each DC load.

[0122] At the same time, the power stored in the backup power supply is supplied to the load, and the power of the backup power supply decreases accordingly. When its power is lower than or equal to the critical value, and there is no external power input to replenish the backup power supply, the system can only stop working and disconnect the charging circuit between the system and the load.

[0123] It should be noted that the system itself also includes photovoltaic DC input, but in actual applications, due to the small power and instability of photovoltaic DC, it is not included in the power distribution of the system. In actual application scenarios, photovoltaic DC can play an auxiliary role, and together with the system's AC input and the power stored in the backup power supply, it is supplied to the load to meet the load's needs.

[0124] In addition, the critical value and preset value of the power level can be adjusted according to actual conditions and are not limited to those described in this embodiment.

[0125] In a specific embodiment, if Fig.10 , 11 Specifically, when the power level of the backup power supply is lower than or equal to a critical value, the first switch unit can be controlled to close to provide a working voltage and current to the enable end of the backup power supply, so that the battery management unit of the backup power supply can work normally.

[0126] At the same time, after the first switch unit is closed, the battery management unit starts and identifies the power of the backup power supply, and also detects the voltage at the output end of the DC / DC converter in the backup power supply. When the power of the backup power supply is lower than or equal to the critical value, and the voltage at the output end of the DC / DC converter in the backup power supply is lower than the preset voltage threshold, the battery management unit sends a power replenishment signal to the power management module.

[0127] The power management module sends a power replenishment confirmation message to the human-computer interaction module according to the power replenishment signal of the battery management unit, and the user further confirms whether to recharge. The power management module feeds back the user's power replenishment confirmation message to the battery management unit.

[0128] When the user confirms to replenish power, the battery management unit controls the second switch unit and the pre-charging unit in the backup power supply to work to replenish power until the power of the backup power supply exceeds a preset value.

[0129] When the user confirms that he does not want to recharge, the battery management unit does not act, and controls the first switch unit to be disconnected, or controls the human-computer interaction module through the power management module to remind the user to manually disconnect the first switch unit.

[0130] In addition, after the charging is completed, if the first switch unit is not disconnected in time, the battery management unit sends a charging completion signal to the power management module, and the power management module reminds the user to disconnect the first switch unit through the human-computer interaction module.

[0131] See also Fig.12 As shown, the present application also provides a control method for an energy storage system, comprising:

[0132] Step S10: After the system is connected to the grid, it is determined whether to supply power to the connected load according to the power of the backup power supply (SOC):

[0133] Step S20, if the power of the backup power supply is higher than the critical value, supplying power to the load according to the preset allocation strategy based on the output power of the backup power supply;

[0134] If the power level of the backup power supply is lower than or equal to the critical value, the control system is powered off.

[0135] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application.

[0136] The above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person skilled in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. An energy storage system, characterized in that: include: DC bus; An electric energy management module, comprising an AC input terminal, a transmission terminal, and a first auxiliary transmission terminal, wherein the AC input terminal is used to connect to an AC charging pile / grid, the transmission terminal is connected to the DC bus, and the electric energy management module is used to convert the AC power of the AC charging pile / grid into DC power; A backup power supply, comprising a first input / output terminal, an enable terminal and a first switch unit, wherein the first input / output terminal is connected to the DC bus, and the enable terminal is connected to the first auxiliary power transmission terminal through the first switch unit; A power output module, whose input end is connected to the DC bus and whose output end is used to connect to an external load; Wherein, the power management module is communicatively connected with the backup power supply and the power output module; By switching the working state of the first switch unit: when the power level of the backup power supply is higher than a critical value, power is transmitted to the DC bus through the first input / output end; and when the power level of the backup power supply is lower than or equal to a critical value, power is supplemented from the DC bus through the first input / output end.

2. The energy storage system according to claim 1, characterized in that: The backup power supply comprises: An energy storage unit, wherein the second input / output terminal is connected to the first input / output terminal, and the power of the energy storage unit is used as the power of the backup power supply; A second switch unit, connected in series between the first input / output terminal and the second input / output terminal; A DC / DC converter, whose input terminal is connected to the second input / output terminal; A battery management unit, whose power supply terminal is respectively connected to the output terminal of the DC / DC converter and the enable terminal; When the power level of the energy storage unit is lower than or equal to a critical value, the battery management unit is used to detect the voltage at the output end of the DC / DC converter, and when the voltage is lower than a preset voltage threshold and the first switch unit is in a closed state, control the second switch unit to close, so as to replenish power for the energy storage unit through the DC bus.

3. The energy storage system according to claim 2, characterized in that: The backup power supply also includes: A third switch unit is connected in series to the input end of the DC / DC converter, and the third switch unit serves as a start switch of the energy storage system and is not closed at the same time as the first switch unit; Wherein, the battery management unit is also used to monitor the working state of the third switch unit: when the third switch unit is closed, a start signal is sent to the power management module.

4. The energy storage system according to claim 2, characterized in that: A first diode is connected in series between the output end of the DC / DC converter and the enable end of the backup power supply, and the anode of the first diode is connected to the output end of the DC / DC converter, and the cathode of the first diode is connected to the enable end of the backup power supply; A second diode is connected in series between the first switch unit and the enable end of the backup power supply, and an anode of the second diode is connected to one end of the first switch unit, and a cathode of the second diode is connected to the enable end of the backup power supply.

5. The energy storage system according to claim 2, characterized in that: The battery management unit is connected to the power management module via a digital signal port, and is used to feed back the emergency fault state signal of the backup power supply to the power management module.

6. The energy storage system according to claim 1, characterized in that: The power management module also includes a photovoltaic input terminal connected to the photovoltaic power source. The power management module is also used to convert the direct current of the photovoltaic power source and output it through the transmission terminal and the first auxiliary transmission terminal.

7. The energy storage system according to claim 6, characterized in that: The power management module also includes: An AC / DC converter, whose input end serves as the AC input end, and the AC / DC converter is used to convert the AC power of the AC charging pile / grid into a DC output; A photovoltaic interface, whose input end serves as the photovoltaic input end, and the photovoltaic interface is used to convert the direct current of the photovoltaic power source and output it; The energy management unit is used to control the operation of the AC / DC converter, the photovoltaic interface, and the power output module, and to communicate and interact with the battery management unit of the backup power supply.

8. The energy storage system according to claim 7, characterized in that: Also includes: A charging pile detection module is respectively connected to the power management module and the AC charging pile for communication and is used to identify the output power of the AC charging pile; The energy management unit is further used to determine the AC input power of the AC / DC converter according to the maximum allowable current of the AC / DC converter and the maximum output current of the AC charging pile / grid.

9. The energy storage system according to claim 1, characterized in that: Also included is an auxiliary power bus; The power management module also includes a second auxiliary power transmission terminal connected to the auxiliary power bus.

10. The energy storage system according to claim 9, characterized in that: The power output module comprises: A DC / AC converter, whose input end is connected to the DC bus and whose output end is used to connect to an external AC load; a fourth switch unit, wherein the enable end of the DC / AC converter is connected to the auxiliary power bus through the fourth switch unit; The power management module is further configured to control the fourth switch unit to cut off the AC output of the DC / AC converter when the AC power output by the DC / AC converter exceeds a preset power threshold.

11. The energy storage system according to claim 1, characterized in that: Also includes: The human-computer interaction module is communicatively connected to the power management module, and is used to display at least one of the power replenishment information of the backup power supply, the charging information of the system and the load, the grid-connected / off-grid information of the system, the fault information of the system, the 4G signal of the system, and the GPS signal of the system.

12. A control method for an energy storage system, characterized in that: include: When the system is connected to the grid, the power of the backup power supply is used to determine whether to supply power to the connected loads: If the power of the backup power supply is higher than the critical value, the load is powered according to the preset allocation strategy based on the system's AC input power and the output power of the backup power supply; If the power of the backup power supply is lower than or equal to the critical value, the backup power supply is supplemented until the power of the backup power supply exceeds the preset value, and then the load is powered according to the preset allocation strategy based on the system's AC input power and the output power of the backup power supply.

13. The control method of the energy storage system according to claim 12, characterized in that: After the system is connected to the grid, the step of determining whether to supply power to the connected load according to the power of the backup power supply comprises: Identify the connection status between the system and the AC charging pile / grid, and determine the system's AC input power: If the system is connected to an AC charging pile, the AC input power of the system is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the AC charging pile; If the system is connected to the grid, the AC input power of the system is determined based on the maximum allowable current of the AC / DC converter in the power management module and the maximum output current of the grid.

14. The control method of the energy storage system according to claim 12, characterized in that: The step of supplying power to the load according to the distribution strategy based on the AC input power of the system and the output power of the backup power supply comprises: Calculating the output power of the AC / DC converter in the power management module according to the AC input power of the system, and taking the sum of the output power of the AC / DC converter and the output power of the backup power supply as the output power of the system; The judgment is made based on the output power of the system and the AC load request power: If the output power of the system is less than the requested power of the AC load, the control system is powered off; If the output power of the system is greater than or equal to the requested power of the AC load, the output power of the system is preferentially supplied to the AC load, and the remaining output power of the system is allocated to the DC load.

15. The control method of the energy storage system according to claim 14, characterized in that: The step of distributing the remaining output power of the system to the DC load comprises: The judgment is made based on the remaining output power of the system and the power requested by the DC load: If the remaining output power of the system is less than the power requested by the DC load, supplying the remaining output power of the system to the DC load according to the allocation strategy; If the remaining output power of the system is greater than or equal to the requested power of the DC load, and the difference between the output power of the AC / DC converter and the requested power of the AC load is less than or equal to the requested power of the DC load, the remaining output power of the system is allocated to each DC load according to the requested output power; If the remaining output power of the system is greater than or equal to the requested power of the DC load, and the difference between the output power of the AC / DC converter and the requested power of the AC load is greater than the requested power of the DC load, the remaining output power of the AC / DC converter is allocated to each DC load according to the requested output power, and the excess output power of the AC / DC converter is used to charge the backup power supply.

16. The control method of the energy storage system according to claim 12, characterized in that: The step of supplying power to the load according to the distribution strategy based on the AC input power of the system and the output power of the backup power supply also includes: When the power level of the backup power supply is lower than or equal to a critical value, the charging circuit between the system and the load is disconnected, and the backup power supply is recharged.

17. The control method of the energy storage system according to claim 12, characterized in that: Also includes: When the system is off-grid, the power level of the backup power supply determines whether to supply power to the connected loads: If the power of the backup power supply is higher than the critical value, the load is supplied with power according to the preset allocation strategy based on the output power of the backup power supply; If the power level of the backup power supply is lower than or equal to the critical value, the control system is powered off.

18. The control method of the energy storage system according to claim 17, characterized in that: The step of supplying power to the load according to the output power of the backup power supply and the preset distribution strategy comprises: The judgment is made based on the output power of the backup power supply and the AC load request power: If the output power of the backup power supply is less than the requested power of the AC load, the control system is powered off; If the output power of the backup power supply is greater than or equal to the requested power of the AC load, the output power of the backup power supply is preferentially supplied to the AC load, and the remaining output power of the backup power supply is allocated to the DC load.

19. The control method of the energy storage system according to claim 18, characterized in that: The step of distributing the remaining output power of the backup power supply to the DC load comprises: The judgment is made based on the remaining output power of the backup power supply and the power requested by the DC load: If the remaining output power of the backup power supply is less than the requested power of the DC load, the remaining output power of the backup power supply is supplied to the DC load through the DC output module according to the allocation strategy; If the remaining output power of the backup power supply is greater than or equal to the requested power of the DC load, the remaining output power of the backup power supply is distributed to each DC load according to the requested output power.

20. The control method of the energy storage system according to claim 17, characterized in that: The step of supplying power to the load according to the preset allocation strategy based on the output power of the backup power supply also includes: When the power level of the backup power supply is lower than or equal to the critical value, the charging circuit between the system and the load is disconnected, and the system is powered off.

21. The control method of the energy storage system according to claim 12, characterized in that: The step of supplementing the backup power supply comprises: Controlling the first switch unit to close and provide working voltage and current to the enable terminal of the backup power supply; According to the power replenishment signal of the battery management unit in the backup power supply, a power replenishment confirmation message is sent to the human-computer interaction module; The power replenishment confirmation information fed back by the human-computer interaction module is received and sent to the battery management unit.

22. The control method of the energy storage system according to claim 21, characterized in that: After the first switch unit is closed, The battery management unit starts and identifies the power level of the backup power supply, and also detects the voltage at the output end of the DC / DC converter in the backup power supply: When the power level of the backup power supply is lower than or equal to a critical value and the voltage at the output end of the DC / DC converter in the backup power supply is lower than a preset voltage threshold, the battery management unit outputs a power replenishment signal.

23. The control method of the energy storage system according to claim 21, characterized in that: After the battery management unit receives the power replenishment confirmation information fed back by the human-computer interaction module: If the power replenishment confirmation information confirms power replenishment, the battery management unit controls the second switch unit in the backup power supply to close for power replenishment until the power of the backup power supply exceeds a preset value, and sends a power replenishment completion signal to the power management module after the power replenishment is completed; If the power replenishment confirmation information confirms that power replenishment is not required, the battery management unit controls the first switch unit to be disconnected.

24. A control method for an energy storage system, characterized in that: include: When the system is off-grid, the power level of the backup power supply determines whether to supply power to the connected loads: If the power of the backup power supply is higher than the critical value, the load is supplied with power according to the preset allocation strategy based on the output power of the backup power supply; If the power level of the backup power supply is lower than or equal to the critical value, the control system is powered off.

25. An energy storage device, characterized in that: include: A main body, and a DC bus, a power management module, a backup power supply and a power output module arranged on the main body; The power management module includes an AC input terminal, a transmission terminal, and a first auxiliary transmission terminal, wherein the AC input terminal is used to connect to an AC charging pile / grid, the transmission terminal is connected to the DC bus, and the power management module is used to convert the AC power of the AC charging pile / grid into DC power; The backup power supply comprises a first input / output terminal, an enable terminal and a first switch unit, the first input / output terminal is connected to the DC bus, and the enable terminal is connected to the first auxiliary power transmission terminal through the first switch unit; The input end of the power output module is connected to the DC bus, and the output end is used to connect to an external load; Wherein, the power management module is communicatively connected with the backup power supply and the power output module; By switching the working state of the first switch unit: when the power level of the backup power supply is higher than a critical value, power is transmitted to the DC bus through the first input / output end; and when the power level of the backup power supply is lower than or equal to a critical value, power is supplemented from the DC bus through the first input / output end.

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