Energy storage converter and battery energy storage system

Abstract

The invention relates to an energy storage converter and a battery energy storage system. The energy storage converter comprises a control module, the control module comprises a control unit, and the control unit is used for being connected with a battery pack; the switch unit is connected between the control unit and the battery pack, and the switch unit comprises a plurality of switch elements which are connected in series; and the battery monitoring unit is respectively connected with the control unit and each switch element, and under the condition that the battery pack is in a power-lack state, if any switch element fails, at least another switch element is controlled to be switched off so as to cut off the connection between the battery pack and the control unit. Redundant reliable design is realized through a plurality of switch elements, and the situation that the service life of the battery is seriously damaged due to damage to the battery in a power-lacking mode caused by main switch faults can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of energy storage, and in particular to an energy storage converter and a battery energy storage system. Background Technology

[0002] The function of a power conversion system (PCS) is to convert the charging and discharging current of a battery. Currently, a battery energy storage system can include battery clusters, related circuits, and a power conversion system. This allows the power conversion system to achieve energy management at the battery cluster level. During system operation, the control unit of the power conversion system can manage and control the energy of the entire energy storage system when it is powered on. However, traditional power supply methods can easily damage batteries in a low-charge mode, severely shortening their lifespan. Summary of the Invention

[0003] Therefore, it is necessary to provide an energy storage converter and battery energy storage system that can effectively avoid the hazards of power loss in order to address the above-mentioned technical problems.

[0004] In a first aspect, this application provides an energy storage converter, comprising:

[0005] The control module includes a control unit, which is used to connect to the battery pack;

[0006] A switching unit is connected between the control unit and the battery pack. The switching unit includes multiple switching elements connected in series.

[0007] The battery monitoring unit is connected to the control unit and each switching element. When the battery pack is in a low-power state, if any switching element fails, it will control at least one other switching element to shut down, thereby disconnecting the battery pack from the control unit.

[0008] In one embodiment, the multiple switching elements connected in series include a main switch and an auxiliary switch connected in series.

[0009] In the event that the battery pack is in a depleted state, if the main switch fails, the auxiliary switch will be shut off to disconnect the battery pack from the control unit.

[0010] In one embodiment, the control module further includes a power supply unit;

[0011] The power supply unit is used to connect to the power grid and the battery pack to supply power to the control unit; the switch unit is connected between the power supply unit and the battery pack.

[0012] In one embodiment, the power supply unit includes a DC switching power supply and an AC switching power supply;

[0013] The first terminal of the AC switching power supply is used to connect to the power grid, and the second terminal of the AC switching power supply is connected to the control unit.

[0014] The first terminal of the DC switching power supply is connected to the battery pack via a switching unit, and the second terminal of the DC switching power supply is connected to the control unit.

[0015] In one embodiment, the control module further includes an undervoltage detection circuit connected to the control unit;

[0016] The undervoltage detection circuit is used to detect the output voltage of the power supply unit; where:

[0017] If the undervoltage detection circuit does not detect the output voltage when both the main switch and the auxiliary switch are closed, the control unit determines that a system power supply failure has occurred.

[0018] When the battery pack is in a low-charge state and the battery monitoring unit controls the main switch to turn off, if the undervoltage detection circuit detects the output voltage, the control unit outputs a main switch fault signal to the battery monitoring unit so that the battery monitoring unit controls the auxiliary switch to turn off.

[0019] In one embodiment, the power supply unit is used to supply power to the undervoltage detection circuit.

[0020] In one embodiment, the energy storage converter further includes a fuse unit, a contactor, and a power conversion unit connected to the control unit;

[0021] One end of the power conversion unit is connected to the battery pack via a contactor and a fuse in sequence, while the other end of the power conversion unit is used to connect to the power grid.

[0022] In one embodiment, the energy storage converter also includes a maintenance switch and a fuse;

[0023] One end of the maintenance switch is connected to the mains power, and the other end of the maintenance switch is connected to one end of the fuse and the switch unit respectively; the other end of the fuse is connected between the contactor and the fuse unit.

[0024] Secondly, this application also provides a battery energy storage system, including a battery pack, a first switching power supply and a second switching power supply, and the aforementioned energy storage converter;

[0025] The first terminal of the second switching power supply is connected to the mains power, and the first terminal of the first switching power supply is connected to the battery pack; the battery monitoring unit is connected to the second terminal of the first switching power supply and the second terminal of the second switching power supply respectively.

[0026] In one embodiment, when the battery pack is in a depleted state, the output voltage of the second switching power supply is controlled to be higher than that of the first switching power supply so that the second switching power supply can supply power to the battery monitoring unit.

[0027] In the aforementioned energy storage converter and battery energy storage system, the battery monitoring unit is connected to the control unit and each switching element respectively. When the battery pack is in a low-power state, it controls the shutdown of at least one switching element to disconnect the battery pack from the control unit. This application achieves a redundant and reliable design through multiple switching elements. That is, when a single switch in the switching unit fails, the other switch can still be reliably shut off, thereby effectively avoiding the damage to the battery in the low-power mode caused by the main switch failure (such as contactor sticking) and the serious damage to its lifespan. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the energy storage converter in one embodiment;

[0030] Figure 2 This is a schematic diagram of the switching unit in one embodiment;

[0031] Figure 3 This is a schematic diagram of the auxiliary switch in one embodiment;

[0032] Figure 4 This is a schematic diagram of the auxiliary switch in another embodiment;

[0033] Figure 5 This is a flowchart illustrating the power supply scheme under normal operating conditions in one embodiment.

[0034] Figure 6 This is a flowchart illustrating a power supply scheme under low power conditions in one embodiment.

[0035] Figure 7 This is a schematic diagram of the structure of an energy storage converter applied to a battery energy storage system in another embodiment;

[0036] Figure 8 This is a schematic diagram of the specific structure of an energy storage converter applied to a battery energy storage system in one embodiment;

[0037] Figure 9 This is a schematic diagram of the specific structure of an energy storage converter applied to a battery energy storage system in another embodiment;

[0038] Figure 10 This is an internal structural diagram of the power supply unit in one embodiment. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0041] It is understood that the terms "first," "second," etc., used in this application may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0042] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0043] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0044] In traditional power supply schemes, battery energy storage systems mainly include battery components, SPS1, SPS2, and energy storage converters. SPS1 can be an external switching power supply box for the energy storage converter, and SPS2 is an external switching power supply box for the energy storage converter that connects to the AC mains power.

[0045] The traditional power supply scheme typically involves external auxiliary power supplies SPS1 and SPS2 drawing power from the battery and mains power respectively, and outputting it to the battery monitoring unit and communication unit within the energy storage converter. This enables real-time battery monitoring and information exchange. The operating status of the power supply unit in the control module of the energy storage converter can be controlled by adjusting the contactor's engagement and disengagement. In this traditional scheme, when the battery is depleted, the power supply unit's energy consumption can be stopped by disconnecting the contactor. However, this traditional scheme has at least the following problem: if the contactor malfunctions (e.g., sticking), the power supply circuit cannot be disconnected, leading to continuous battery drain and severely impacting battery life.

[0046] To address the problems in the traditional solutions mentioned above, this application proposes a redundancy design. When one contactor experiences a single fault, the other contactor can still reliably shut off, thereby effectively preventing contactor failure from harming the battery in the low-power mode and severely damaging its lifespan.

[0047] Taking battery energy storage systems as an example, a battery energy storage system includes a battery pack, such as... Figure 1 As shown, an energy storage converter 10 in one embodiment may include:

[0048] Control module 100, the control module includes control unit 102, the control unit 102 is used to connect to the battery pack;

[0049] The switching unit 110 is connected in the circuit of the control unit 102 to the battery pack. The switching unit includes multiple switching elements 112 connected in series.

[0050] The battery monitoring unit 120 is connected to the control unit 102 and each switching element respectively. When the battery pack is in a low-power state, if any switching element fails, it controls the shutdown of at least another switching element to disconnect the battery pack from the control unit 102.

[0051] Specifically, the control module 100 in the energy storage converter 10 may include a control unit 102. Exemplarily, the control unit 102 can be connected to a battery pack to supply power to the control unit 102. Furthermore, the control unit 102 can also be connected to the power grid. Optionally, the control unit 102 may employ a DSP (Digital Signal Processing). It should be noted that the control unit may also employ, but is not limited to, CPLD (Complex Programmable Logic Device) / FPGA (Field Programmable Gate Array), ARM (Advanced RISC Machines), and MIPS (Million Instructions Per Second), etc., and this application does not limit its application in this regard.

[0052] In this embodiment, the switch unit 110 is connected in the line connecting the control unit 102 to the battery pack, and is used for access control of the operation of the control unit 102. For example, the battery monitoring unit 120 can control the connection and disconnection between the battery pack and the control unit 102 through the switch unit 110.

[0053] The switching unit 110 may include multiple switching elements 112 connected in series to achieve a redundant and reliable design. The battery monitoring unit 120 connected to the control unit 102 can be connected to multiple switching elements 112 respectively, so that in a fault mode (e.g., when any one switching element fails), at least one other switching element can still be reliably turned off. This allows the control unit 102 to stop consuming energy from the battery when the battery pack is in a low-charge state by reliably turning off the switching unit 110, without hindering the internal information detection of the system. It should be noted that the number of switching elements is not limited in the embodiments of this application.

[0054] Optionally, the switching element 112 can be a controllable switch, such as a power switching device (e.g., a contactor, a relay, etc.). It is understood that the above-mentioned switching unit and switching element can also take other forms, and are not limited to the forms mentioned in the above embodiments, as long as they can achieve a stable and reliable shutdown function.

[0055] For example, the battery monitoring unit 120 can be used to collect information about the battery pack, such as voltage, current, temperature, and SOC (State of Charge).

[0056] For example, such as Figure 1As shown, the energy storage converter 10 may further include a power conversion unit connected to the control unit 102, which is connected between the battery pack and the power grid. The power conversion unit enables energy transfer between the battery pack and the power grid, i.e., charging and discharging of the battery.

[0057] The aforementioned energy storage converter achieves a redundant and reliable design through multiple switching elements. When applied to battery energy storage systems, it provides protection against power loss under fault modes, greatly enhancing the reliability of the system.

[0058] Furthermore, regarding the multiple switching elements in the switching unit, in some examples, such as Figure 2 As shown, the multiple switching elements connected in series include a main switch and an auxiliary switch connected in series.

[0059] In the event that the battery pack is in a depleted state, if the main switch fails, the auxiliary switch will be turned off to disconnect the battery pack from the control unit 102.

[0060] Specifically, the switching unit 110 may include a main switch and an auxiliary switch connected in series to achieve a dual-redundancy reliable design. The battery monitoring unit 120 connected to the control unit 102 is connected to the main switch and the auxiliary switch respectively. In a fault mode (e.g., when the main switch fails), the other auxiliary switch can still be reliably turned off. This allows the control unit 102 to stop consuming energy from the battery when the battery pack is in a low-charge state by reliably turning off the switching unit 110, without hindering the internal information detection of the system.

[0061] Optionally, the main switch and auxiliary switch can be power switching devices, such as contactors and relays. It is understood that the above-mentioned switching unit can also take other forms, not limited to those mentioned in the embodiments above, as long as it can achieve a stable and reliable shutdown function.

[0062] The aforementioned energy storage converter achieves a dual-redundancy reliable design by adding an auxiliary switch. When applied to battery energy storage systems, it provides protection against power loss in fault modes, greatly enhancing the reliability of the system.

[0063] The following example uses contactors as both the main switch and the auxiliary switch, where the main switch is KM1 and the auxiliary switch is KM11. In one embodiment, as follows... Figure 3 As shown, the control module may also include a power supply unit;

[0064] The power supply unit is used to connect to the power grid and the battery pack to supply power to the control unit; the switch unit is connected between the power supply unit and the battery pack.

[0065] Specifically, the control module in the energy storage converter may include a power supply unit and a control unit, wherein the power supply unit is used to supply power to the control unit. For example, the power supply unit may be used to connect to both the power grid and the battery pack to supply power to the control unit 102.

[0066] In this embodiment, the switching unit can be connected in the line connecting the power supply unit to the battery pack for access control of the control unit's operation. For example, the battery monitoring unit can control the connection between the battery pack and the power supply unit via the switching unit. For instance, taking a switching unit comprising a main switch and an auxiliary switch connected in series to achieve a dual-redundancy reliable design, the battery monitoring unit connected to the control unit is connected to both the main switch and the auxiliary switch. When the main switch fails, it controls the auxiliary switch to turn off, so that when the battery pack is in a low-power state, the connection between the power supply unit and the battery pack can be reliably disconnected through the switching unit.

[0067] It is understandable that, based on the above dual redundancy design, in practical applications, in order to optimize the power supply scheme, in an exemplary embodiment, such as... Figure 4 As shown, the auxiliary switch can also be a normally closed switch.

[0068] Specifically, under normal operating conditions, the auxiliary switch also needs to be closed, increasing power consumption. To address this, this embodiment designs the auxiliary switch as a normally closed switch, ensuring it remains in a self-closing state under normal operating conditions, consuming power only when it needs to be opened.

[0069] In one embodiment, the power supply unit includes a DC switching power supply and an AC switching power supply;

[0070] The first terminal of the AC switching power supply is used to connect to the power grid, and the second terminal of the AC switching power supply is connected to the control unit.

[0071] The first terminal of the DC switching power supply is connected to the battery pack via a switching unit, and the second terminal of the DC switching power supply is connected to the control unit.

[0072] Specifically, the power supply unit may include a DC switching power supply and an AC switching power supply; wherein, the first terminal of the AC switching power supply (ACSPS, auxiliary power supply) is connected to the power grid, and the second terminal of the AC switching power supply is connected to the control unit; the first terminal of the DC switching power supply (DC SPS) can be connected to the battery pack through the switching unit, and the second terminal of the DC switching power supply is connected to the control unit. In some examples, the operating state of the DC switching power supply can be controlled by controlling the on / off state of the main switch in the switching unit, and a more reliable shutdown control can be ensured by using an auxiliary switch in the switching unit.

[0073] Taking a scenario where both the main switch and auxiliary switch are contactors, and the power supply unit includes both DC and AC switching power supplies, as an example... Figure 4 As shown, the main switch (KM1) is used for the access control of the DC switching power supply, and the auxiliary switch (KM11) is used for the auxiliary control of the DC switching power supply. The battery monitoring unit can be connected in series with the contactor coil via the switch, and the power supply unit is connected to the battery pack through the contactor's switch contacts. When the contactor coil is energized, the coil current generates a magnetic field. This magnetic field causes the stationary iron core to generate an electromagnetic attraction, drawing in the moving iron core and actuating the contacts. The normally closed contacts open, and the normally open contacts close. When the coil is de-energized, the electromagnetic attraction disappears, and the armature is released by the release spring, causing the contacts to return to their original position. The normally open contacts open, and the normally closed contacts close. The auxiliary switch KM11 is a normally closed switch.

[0074] In one embodiment, the control module may further include an undervoltage detection circuit connected to the control unit;

[0075] The undervoltage detection circuit is used to detect the output voltage of the power supply unit; where:

[0076] If the undervoltage detection circuit does not detect the output voltage when both the main switch and the auxiliary switch are closed, the control unit determines that a system power supply failure has occurred.

[0077] When the battery pack is in a low-charge state and the battery monitoring unit controls the main switch to turn off, if the undervoltage detection circuit detects the output voltage, the control unit outputs a main switch fault signal to the battery monitoring unit so that the battery monitoring unit controls the auxiliary switch to turn off.

[0078] Specifically, this application uses an undervoltage detection circuit for detection and feedback to assist the operation of the switching unit (e.g., an auxiliary switch). This undervoltage detection circuit is connected to a control unit and can be used to detect the output voltage of the power supply unit.

[0079] For example, such as Figure 5 As shown, when the battery energy storage system is in normal operating condition, the battery monitoring unit issues a energizing command, causing the main switch to be closed and the auxiliary switch to be normally closed. At this time, if the undervoltage detection circuit detects the output voltage of the power supply unit, it indicates that the system is operating normally. If the undervoltage detection circuit does not detect the output voltage of the power supply unit, it indicates a power supply failure in the system, and the system cannot operate and requires maintenance.

[0080] Furthermore, such as Figure 6As shown, when the battery pack is in a low-charge state, the battery monitoring unit sends a disconnect command to control the main switch to turn off. At this time, if the undervoltage detection circuit does not detect an output voltage, it indicates that the system is in a low-charge protection state. If the undervoltage detection circuit detects an output voltage, it can transmit the signal to the control unit, which can then output a main switch fault signal to the battery monitoring unit, indicating that the system's low-charge protection has failed. In this case, the battery monitoring unit sends a disconnect command to the auxiliary switch to control its shutdown. Optionally, the undervoltage detection circuit can detect an output voltage of 12V from the power supply unit.

[0081] In one embodiment, the power supply unit can be used to power the undervoltage detection circuit.

[0082] Specifically, in this embodiment, the undervoltage detection circuit can be powered by an AC switching power supply, such as 12V AC voltage.

[0083] In one embodiment, the energy storage converter may further include a fuse unit, a contactor, and a power conversion unit connected to the control unit; one end of the power conversion unit is connected to the battery pack in sequence through the contactor and the fuse unit, and the other end of the power conversion unit is used to connect to the power grid.

[0084] In one embodiment, the energy storage converter may further include a maintenance switch and a fuse;

[0085] One end of the maintenance switch is connected to the mains power, and the other end of the maintenance switch is connected to one end of the fuse and the switch unit respectively; the other end of the fuse is connected between the contactor and the fuse unit.

[0086] It is understandable that for devices such as fuse units, contactors, power conversion units, maintenance switches and fuses, please refer to the description in the battery energy storage system below, and will not be repeated here.

[0087] The aforementioned energy storage converter provides handling measures and signal feedback for power supply and power outage anomalies, which is helpful for actual operation and greatly enhances the reliability of the system.

[0088] In one embodiment, this application also provides a battery energy storage system, which may include a battery pack, a first switching power supply and a second switching power supply, as well as the aforementioned energy storage converter;

[0089] The first terminal of the second switching power supply is connected to the mains power, and the first terminal of the first switching power supply is connected to the battery pack; the battery monitoring unit is connected to the second terminal of the first switching power supply and the second terminal of the second switching power supply respectively.

[0090] Specifically, the battery energy storage system may include a battery pack, a first switching power supply and a second switching power supply, wherein the first terminal of the second switching power supply is connected to the mains power, the first terminal of the first switching power supply is connected to the battery pack, and the battery monitoring unit is connected to the second terminal of the first switching power supply and the second terminal of the second switching power supply respectively.

[0091] Optionally, the first switching power supply can be a switching power supply box, and the second switching power supply can also be a switching power supply box. The first switching power supply and the second switching power supply serve as external auxiliary power supplies, which can draw power from the battery pack and the mains power (e.g., AC mains power) respectively, to supply the internal components of the energy storage converter such as the battery monitoring unit 120.

[0092] In some examples, for the power supply of internal components of the energy storage converter, such as the battery monitoring unit, the first and second switching power supplies can utilize diode clamping to prioritize AC power over battery pack power supply, thereby reducing battery losses. The details regarding the diode clamping configuration will be described later and will not be repeated here.

[0093] In one embodiment, the energy storage converter may further include a fuse unit, a contactor, and a power conversion unit connected to the control unit;

[0094] One end of the power conversion unit is connected to the battery pack via a contactor and a fuse in sequence, and the other end of the power conversion unit is used to connect to the power grid; wherein, the first end of the first switching power supply is connected between the contactor and the fuse.

[0095] Specifically, this application can also be used in conjunction with a fuse unit (e.g., a fuse), and the energy storage converter can also include a fuse unit, a contactor, and a power conversion unit connected to the control unit; wherein, the fuse unit can be used to protect the battery and prevent overcurrent.

[0096] It is understood that the contactor, fuse unit, etc. in the embodiments of this application can be understood as a device with circuit breaking function (i.e., circuit breaking element), which can disconnect the electrical connection between the battery pack and the power conversion unit to protect the safety of the battery energy storage system. It is simple to operate and has strong applicability.

[0097] In practical applications, taking multiple switching elements connected in series, including a main switch and an auxiliary switch connected in series, as an example, and exemplifying a first switching power supply being a switching power supply box (SPS1) and a second switching power supply being a switching power supply box (SPS2), as follows... Figure 8 or Figure 9As shown, contactors KM2 and KM3 can be used to control the connection of the battery pack to the power conversion unit. The fuse unit can include fuses FU1 and FU2 to protect the circuit. Optionally, FU1 and / or FU2 can be explosive fuses, which can promptly disconnect the connection between the battery pack and the power conversion unit. For example, the control unit can issue a tripping command to the explosive fuse when the current value at the DC terminal of the power conversion unit meets a threshold condition (e.g., greater than or equal to a corresponding threshold), thus disconnecting the electrical connection between the battery pack and the power conversion unit. This method is simple to control and highly applicable. In some instances, FU1 and FU2 are respectively an explosive fuse and a circuit breaker, thus achieving dual protection of the circuit. For example, when the explosive fuse fails, the circuit breaker can disconnect the electrical connection between the battery pack and the power conversion unit, thereby improving system safety.

[0098] In one embodiment, the energy storage converter may further include a maintenance switch and a fuse;

[0099] One end of the maintenance switch is connected to the first terminal of the first switching power supply, and the other end of the maintenance switch is connected to one end of the fuse and the switching unit respectively; the other end of the fuse is connected between the contactor and the fuse unit.

[0100] Specifically, such as Figure 8 or Figure 9 As shown, the energy storage converter may include a maintenance switch SQ1 and a fuse FU3. One end of the maintenance switch SQ1 is connected to the first terminal of the switching power supply box SPS1 (i.e., the first switching power supply), and the other end of the maintenance switch SQ1 is connected to one end of the fuse FU3 and the main switch KM1. The other end of the fuse FU3 is connected between the contactor KM2 and the fuse FU1. In some examples, the fuse FU3 may be an explosive fuse, wherein the action time of the explosive fuse may be shorter than the effective time of the fuse, thereby enabling timely disconnection of the connection via the explosive fuse.

[0101] Understandably, the aforementioned fuses and circuit breakers can be used to protect the battery pack, providing effective protection against short circuits in either the external wiring of the control unit or the external wiring of the switching power supply box. Furthermore, the maintenance switch SQ1 allows the battery storage system to be disconnected for maintenance when needed.

[0102] Furthermore, although not shown, Figure 8 or Figure 9 The auxiliary switch KM11 can also be a normally closed switch.

[0103] In one embodiment, when the battery pack is in a depleted state, the output voltage of the second switching power supply is controlled to be higher than that of the first switching power supply so that the second switching power supply can supply power to the battery monitoring unit.

[0104] Specifically, when the battery pack is in a depleted state, by powering the battery monitoring unit with a second switching power supply, battery pack losses can be reduced. For example, this application can use diode clamping to control the output voltage of the second switching power supply to be higher than the output voltage of the first switching power supply.

[0105] Optionally, regarding the diode clamping configuration of the first and second switching power supplies in the embodiments of this application: as follows: Figure 8 The position of diode D1, as shown, ensures that the external interconnection scheme prioritizes AC throughout the entire process to reduce battery loss. Specifically, when the battery is low on charge, the battery monitoring unit consumes AC power. Figure 9 The position of diode D2 is shown. The external mutual top scheme is DC priority. When the battery is in a low-charge state, the output voltage of SPS1 can be controlled to be lower than the output voltage of AC-side SPS2 based on diode D2. Thus, in the low-charge state, AC priority is switched, thereby reducing battery loss.

[0106] In one embodiment, the energy storage converter may further include a communication unit connected between the battery monitoring unit and the control unit.

[0107] Specifically, such as Figure 8 or Figure 9 As shown, the communication unit is connected between the battery monitoring unit and the control unit; the communication unit serves as the communication and interaction system of the whole machine, and can perform information transmission between units, human-machine interaction, and interaction with the central control center.

[0108] To further illustrate the scheme of this application, a specific example is provided below. Figure 8 Taking the specific circuit shown as an example, the power supply methods of the DC switching power supply (DC SPS) and AC switching power supply (AC SPS) in the power supply unit will be explained in detail, such as... Figure 10 As shown, the energy storage converter is applied in the battery energy storage system and adds an undervoltage detection circuit to detect the DC SPS output voltage of 12V. The power supply for this undervoltage detection circuit can be provided by 12V_A. This undervoltage detection circuit is used for detection and feedback to assist the operation of KM11.

[0109] Furthermore, such as Figure 10As shown, the ARM chip is the communication unit chip, and the DSP chip is the control unit chip. The 12V supply can power devices such as drivers and contactors. The undervoltage detection circuit is used to obtain the current power supply status; if the 12V is low, the DSP can report a fault, thus identifying the operating status of the DC switching power supply (DC SPS) or AC switching power supply (ACSPS).

[0110] The specific operating logic can be as follows: Under normal operating conditions (when the battery energy storage system needs to operate), the battery monitoring unit issues a KM1 activation command, and KM11 is in a normally closed state. At this time, the undervoltage detection circuit should detect a 12V voltage, indicating that the system is operating normally. If the undervoltage detection circuit does not detect a 12V voltage at this time, it indicates a power supply failure in the system, and the machine cannot operate and needs to be repaired.

[0111] When the battery is in a low-charge state, the battery monitoring unit sends a KM1 disconnect command. At this time, when the undervoltage detection circuit detects that there is no 12V voltage, it transmits the signal to the DSP, and then to the upper level through the communication unit, indicating that the machine is in a low-charge protection state.

[0112] If the battery monitoring unit issues a KM1 disconnect command, and the undervoltage detection circuit detects a 12V voltage, it transmits the signal to the DSP, which in turn transmits it to the upper level via the communication unit, indicating that the machine's anti-power-loss state has failed. Further, the battery monitoring unit issues a KM11 disconnect command, which energizes the KM11 coil.

[0113] Optionally, Figure 10 The diagram also shows a Buck circuit (also known as a step-down circuit), an isolated DC / DC converter, a fan load, 5V_S basic insulation, 12V_A functional insulation, 12V_S basic insulation, 24V_S basic insulation, 14V_S basic insulation, a 12V functional insulation load, and a RACK BMS (control module for a high-voltage BMS). Here, BMS can refer to a Battery Management System. It is understood that the above power supply unit can also take other forms, not limited to those mentioned in the embodiments, as long as it can achieve the corresponding power supply function. The above energy storage converter can be applied to battery energy storage systems or similar devices.

[0114] This application, applied to battery energy storage systems, addresses the protection measures against power loss under fault modes. It incorporates fault detection logic for real-time, comprehensive detection and protection, enhancing system reliability.

[0115] The aforementioned battery energy storage system achieves a redundant and reliable design through multiple switching elements. When a single switch in the switching unit fails, the other switch can still reliably shut off, thereby effectively preventing the main switch failure (such as contactor sticking) from harming the battery in the low-power mode and severely damaging its lifespan.

[0116] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0118] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An energy storage converter, characterized in that, include: The control module includes a control unit for connecting to the battery pack; A switching unit is connected between the control unit and the battery pack, and the switching unit includes a plurality of switching elements connected in series. The battery monitoring unit is connected to the control unit and each of the switching elements respectively. When the battery pack is in a low-power state, if any of the switching elements fails, it controls the shutdown of at least one of the switching elements to disconnect the battery pack from the control unit.

2. The energy storage converter according to claim 1, characterized in that, The series-connected switching elements include a main switch and an auxiliary switch connected in series. In the event that the battery pack is in a depleted state, if the main switch fails, the auxiliary switch will be turned off to disconnect the battery pack from the control unit.

3. The energy storage converter according to claim 2, characterized in that, The control module also includes a power supply unit; The power supply unit is used to connect the power grid and the battery pack to supply power to the control unit; the switch unit is connected between the power supply unit and the battery pack.

4. The energy storage converter according to claim 3, characterized in that, The power supply unit includes a DC switching power supply and an AC switching power supply; The first terminal of the AC switching power supply is used to connect to the power grid, and the second terminal of the AC switching power supply is connected to the control unit. The first terminal of the DC switching power supply is connected to the battery pack through the switching unit, and the second terminal of the DC switching power supply is connected to the control unit.

5. The energy storage converter according to claim 3 or 4, characterized in that, The control module also includes an undervoltage detection circuit, which is connected to the control unit. The undervoltage detection circuit is used to detect the output voltage of the power supply unit; wherein: When both the main switch and the auxiliary switch are closed, if the undervoltage detection circuit does not detect the output voltage, the control unit determines that a system power supply failure has occurred. When the battery pack is in a depleted state and the battery monitoring unit controls the main switch to turn off, if the undervoltage detection circuit detects the output voltage, the control unit outputs a main switch fault signal to the battery monitoring unit so that the battery monitoring unit controls the auxiliary switch to turn off.

6. The energy storage converter according to claim 5, characterized in that, The power supply unit is used to supply power to the undervoltage detection circuit.

7. The energy storage converter according to claim 1, characterized in that, The energy storage converter also includes a fuse unit, a contactor, and a power conversion unit connected to the control unit; One end of the power conversion unit is connected to the battery pack in sequence through the contactor and the fuse unit, and the other end of the power conversion unit is used to connect to the power grid.

8. The energy storage converter according to claim 7, characterized in that, The energy storage converter also includes a maintenance switch and a fuse; One end of the maintenance switch is connected to the mains power, and the other end of the maintenance switch is connected to one end of the fuse and the switch unit respectively; the other end of the fuse is connected between the contactor and the fuse unit.

9. A battery energy storage system, characterized in that, It includes a battery pack, a first switching power supply and a second switching power supply, and an energy storage converter as described in any one of claims 1 to 8; The first terminal of the second switching power supply is connected to the mains power, and the first terminal of the first switching power supply is connected to the battery pack; the battery monitoring unit is connected to the second terminal of the first switching power supply and the second terminal of the second switching power supply respectively.

10. The battery energy storage system according to claim 9, characterized in that, When the battery pack is in a depleted state, the output voltage of the second switching power supply is controlled to be higher than that of the first switching power supply so that the second switching power supply can supply power to the battery monitoring unit.

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