High-voltage box suitable for sodium ion energy storage system, sodium ion energy storage system and control method

Abstract

The invention provides a high-voltage box suitable for a sodium ion energy storage system, the sodium ion energy storage system and a control method. The high-voltage box comprises a soft start circuit, a filter circuit, a master control BCM and a switching circuit, the filter circuit is connected with an external energy storage PCS; the filter circuit is connected with the soft start circuit; the soft start circuit and the filter circuit are respectively connected with a first positive electrode end and a first negative electrode end of the switching circuit; the switching circuit is provided with a second positive end and a second negative end which are respectively connected with the positive end and the negative end of an external sodium ion battery PACK1; the switching circuit is provided with a third positive end and a third negative end which are respectively used for being connected with the positive end and the negative end of an external sodium ion battery PACK2; the main control BCM is respectively connected with the soft start circuit, the filter circuit and the switching circuit, when the external sodium ion battery PACK1 and the external sodium ion battery PACK2 are controlled by the switching circuit to be switched between the series connection state and the parallel connection state, current and voltage abrupt changes are stabilized, and the impact on the external energy storage PCS in the switching process is avoided.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a high-voltage box suitable for a sodium ion energy storage system, a sodium ion energy storage system and a control method. Background Art

[0002] At present, major battery manufacturers are vigorously developing sodium-ion battery technology due to the advantages of sodium being abundant in resources, cheap and easy to obtain. As sodium-ion battery technology matures and gradually becomes industrialized, it is expected that sodium-ion batteries will be used for large-scale energy storage in the next few years.

[0003] Sodium-ion batteries mainly rely on the movement of sodium ions between the positive and negative electrodes to work, which is similar to the working principle of lithium-ion batteries. Both are called "rocking chair" batteries. However, the positive electrode material of sodium-ion batteries usually has a higher voltage, which can reach 4V, while the voltage of the negative electrode material is lower, usually between 0.01V and 1V. The battery voltage window range is relatively wide. The voltage of sodium-ion battery cells in the full SOC (remaining power / remaining charge level) range is between 1.5V and 4V, and the voltage window range is 2.17 times that of lithium-ion batteries from 2.5V to 3.65V. Existing energy storage PCS (energy storage converter) is not suitable for sodium-ion energy storage systems with a wide voltage window range. The common solution is to configure a DCDC converter for DC voltage conversion or to use a higher voltage power device energy storage PCS for adaptation. The DC-DC converter realizes the transfer of electric energy and the rise and fall of voltage by dividing the input voltage into several pulse cycles and using switching tubes to control the duty cycle of these pulse cycles. This pulse width modulation (PWM) technology is the core of the DC-DC converter. It adjusts the output voltage by controlling the on-time of the switch tube, thereby achieving a stable output voltage. However, this method requires the pulse width modulation of the switch tube and the electromagnetic conversion operation of the transformer (or inductor) to be maintained during use, which increases system consumption and reduces system efficiency. The use of energy storage PCS with higher voltage power devices will result in the need to replace the energy storage PCS in large quantities, resulting in a high system conversion cost.

[0004] In view of this, a high-voltage box, a sodium-ion energy storage system and a control method suitable for a sodium-ion energy storage system are needed. Summary of the invention

[0005] In view of the problem that the conversion cost is high when replacing the external energy storage PCS in the prior art or the system efficiency is reduced by adding a DCDC converter, the present invention provides a high-voltage box, a sodium ion energy storage system and a control method suitable for a sodium ion energy storage system, which can not only avoid the existing problem of replacing the external energy storage PCS, but also avoid the problem of reduced system efficiency. The specific technical solution is as follows: A high-voltage box suitable for a sodium-ion energy storage system, comprising: a soft-start circuit, a filter circuit, a Hall sensor, a voltage sensor, a master control BCM and a switch circuit; the first positive terminal of the filter circuit is connected to the positive terminal of an external energy storage PCS; the first negative terminal of the filter circuit is connected to the negative terminal of the external energy storage PCS; the second positive terminal of the filter circuit is connected to the first end of the soft-start circuit; the second end of the soft-start circuit and the second negative terminal of the filter circuit are respectively connected to the first positive terminal and the first negative terminal of the switch circuit; the Hall sensor is connected in series between the second negative terminal of the filter circuit and the first negative terminal of the switch circuit; the switch circuit is also provided with a second positive terminal and a second negative terminal; the second positive terminal of the switch circuit is connected to the positive terminal of an external sodium-ion battery PACK1; the second negative terminal of the switch circuit is connected to the negative terminal of the external sodium-ion battery PACK1; the switch circuit is also provided with a third positive terminal and a third negative terminal; the third positive terminal of the switch circuit is connected to the positive terminal of the external sodium ion battery PACK2; the third negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK2; the voltage sensor is arranged at the first positive terminal and the first negative terminal of the switch circuit, and is connected to the main control BCM; the main control BCM is respectively connected to the soft start circuit, the filter circuit, the Hall sensor and the switch circuit to control the switch circuit so that the external sodium ion battery PACK1 and the external sodium ion battery PACK2 are switched between parallel and series states, and at the same time, the filter capacity level of the filter circuit is adjusted according to the change of the series-parallel connection state between the external sodium ion battery PACK1 and the external sodium ion battery PACK2, so as to smooth the current and voltage mutations generated by the series-parallel switching of the external sodium ion batteries in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process.

[0006] Furthermore, the switching circuit includes a switch DCSSR1, a switch DCSSR2 and a switch DCSSR3; the first positive terminal of the switching circuit is directly led out as the second positive terminal of the switching circuit; the first positive terminal of the switching circuit is connected in series with the switch DCSSR3 to serve as the third positive terminal of the switching circuit; the first negative terminal of the switching circuit is directly led out as the third negative terminal of the switching circuit; the first negative terminal of the switching circuit is connected in series with the switch DCSSR2 to serve as the second negative terminal of the switching circuit; the switch DCSSR1 is connected in series between the second negative terminal of the switching circuit and the third positive terminal of the switching circuit; the master control BCM is connected to the switch DCSSR1, the switch DCSSR2 and the switch DCSSR3 to control the on / off state of each switch.

[0007] Furthermore, the switch circuit also includes a NOT gate N1; the input end of the NOT gate N1 is connected to the control end of the switch DCSSR2 and the control end of the switch DCSSR3; the input end of the NOT gate N1 is connected to the main control BCM; the output end of the NOT gate N1 is connected to the control end of the switch DCSSR1.

[0008] Furthermore, the filter circuit includes a first LC circuit and a second LC circuit; the first LC circuit and the second LC circuit are connected in parallel.

[0009] Further, the first LC circuit includes a switch K11, a switch K12, an inductor L1 and a capacitor C1; the second LC circuit includes a switch K21, a switch K22, an inductor L2 and a capacitor C2; the first end of the switch K11 is connected to the first end of the switch K12 and the first end of the inductor L1; the second end of the switch K12 is connected to the first end of the capacitor C1; the first end of the switch K21 is connected to the first end of the switch K22 and the first end of the inductor L2; the second end of the switch K22 is connected to the first end of the capacitor C2; the switch K11 The second end of the inductor L1 is connected to the second end of the inductor L2, and the connection point serves as the first positive terminal of the filter circuit; the second end of the capacitor C1 is connected to the second end of the capacitor C2, the second end of the capacitor C1 serves as the first negative terminal of the filter circuit, and the second end of the capacitor C2 serves as the second negative terminal of the filter circuit; the master control BCM is connected to the switch K11, the switch K12, the switch K21 and the switch K22 to control the filtering capability level state of the filter circuit.

[0010] Furthermore, the soft start circuit includes a relay K31, a relay K32 and a resistor R31; the first end of the relay K31 is connected to the first end of the resistor R31; the second end of the relay K31 is connected to the first end of the relay K32, and the connection point serves as the first end of the soft start circuit; the second end of the resistor R31 is connected to the second end of the relay K32, and the connection point serves as the second end of the soft start circuit; the soft start circuit is used to connect the relay K31 and the resistor R31 for pre-charging before officially connecting the relay K32 of the main path, so as to prevent excessive impact on the external sodium ion battery.

[0011] Furthermore, it also includes a first linkage circuit; the first linkage circuit includes an OR gate N2, a resistor R32 and a resistor R34; the first end of the resistor R32 is connected to the first end of the resistor R34, and the connection point is connected to the first input end of the OR gate N2; the second end of the resistor R34 is grounded; the second end of the resistor R32 is connected to the first end of the resistor R31; the second end input end of the OR gate N2 is connected to the master control BCM; the output end of the OR gate N2 is respectively connected to the switch K21 and the switch K22.

[0012] Furthermore, it also includes a second linkage circuit; the second linkage circuit includes a transistor N3, a capacitor C3 and a resistor R33; the collector of the transistor N3 is connected to the power supply VCC, the base is connected to the output end of the NOT gate N1, and the emitter is connected to the first end of the capacitor C3; the second end of the capacitor C3 is connected to the first end of the resistor R33, and the connection point is connected to the third input end of the OR gate N2; the second end of the resistor R33 is grounded.

[0013] A sodium ion energy storage system comprises the above-mentioned high-voltage box suitable for the sodium ion energy storage system, and also comprises an external energy storage PCS, a slave control BMM, an energy management system EMS, an external sodium ion battery PACK1 and an external sodium ion battery PACK2; the first positive terminal and the first negative terminal of the filter circuit are respectively connected to the positive terminal and the negative terminal of the external energy storage PCS; the second positive terminal and the second negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK1; the third positive terminal and the third negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK2; the master control BCM is respectively connected to the external energy storage PCS, the slave control BMM and the energy management system EMS.

[0014] A sodium ion energy storage system control method is used to control the sodium ion energy storage system described above, comprising the following steps: The high-voltage box performs a self-test after power-on. The main control BCM switches the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2 in series or in parallel, and records the voltage values ​​of the series or in parallel. When the series voltage value is greater than the maximum voltage of the external energy storage PCS DC side and the parallel voltage is less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to be disconnected, the switches DCSSR2 and DCSSR3 to be turned on, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the parallel buck mode; When the series voltage value is greater than the minimum voltage of the external energy storage PCS DC side and less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to turn on, the switch DCSSR2 and the switch DCSSR3 to turn off, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the series operation boost mode; When the series voltage value is less than the minimum voltage of the external energy storage PCS DC side, the main control BCM sends a charge and discharge prohibition instruction to the external energy storage PCS and the energy management system EMS, reporting a total voltage undervoltage fault; In the case of charging, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft start circuit to perform charging soft start in the manner of pre-charging first and then formal charging to prevent the impact damage to the battery caused by large current, and adjusts the series and parallel connection according to the battery voltage; In the discharge situation, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft-start circuit to perform discharge soft-start in the manner of pre-discharge first and then formal discharge to prevent large current from causing impact damage to the external energy storage PCS, and adjusts the series and parallel connection according to the battery voltage.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Based on the traditional high-voltage box, it is based on the wide voltage characteristics of sodium-ion energy storage batteries, uninterrupted power supply and rapid protection requirements of energy storage systems. The high-voltage box uses the main control BCM as the control center. According to the collected battery status data, the operating status of the energy storage system and the control request of the upper system, it controls the on and off of the DC solid-state switch DCSSR and cooperates with the voltage and current conversion of the external energy storage PCS to achieve nanosecond-level seamless switching of high and low voltages of the battery cluster. Different LC circuit groups are configured to smooth the current and voltage mutations caused by the series-parallel switching of external sodium-ion batteries in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process. Under the premise that the existing external energy storage PCS converter is not modified, the voltage-adjustable high-voltage box is used to achieve efficient and low-cost seamless access to the wide voltage range sodium-ion energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0017] Figure 1It is a structural schematic diagram of a high-voltage box suitable for a sodium ion energy storage system; Figure 2 A schematic diagram of a first circuit structure of a high-voltage box suitable for a sodium-ion energy storage system; Figure 3 A schematic diagram of a second circuit structure of a high-voltage box suitable for a sodium-ion energy storage system; Figure 4 It is a structural schematic diagram of a sodium ion energy storage system; Figure 5 It is a schematic diagram of the series connection structure of high-voltage boxes suitable for sodium ion energy storage system; Figure 6 This is a schematic diagram of the parallel state structure of high-voltage boxes suitable for sodium ion energy storage systems. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be understood that when used in this application document, the terms "include" and "comprising" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0020] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this application document, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms.

[0021] It should be further understood that the term “and / or” used in the present application documents refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0022] Embodiment 1 like Figure 1The figure shows a schematic diagram of the structure of a high-voltage box suitable for a sodium ion energy storage system, including: a soft start circuit, a filter circuit, a Hall sensor, a voltage sensor, a master control BCM and a switch circuit; the first positive terminal of the filter circuit is connected to the positive terminal of an external energy storage PCS; the first negative terminal of the filter circuit is connected to the negative terminal of the external energy storage PCS; the second positive terminal of the filter circuit is connected to the first end of the soft start circuit; the second end of the soft start circuit and the second negative terminal of the filter circuit are respectively connected to the first positive terminal and the first negative terminal of the switch circuit; the Hall sensor is connected in series between the second negative terminal of the filter circuit and the first negative terminal of the switch circuit; the switch circuit is also provided with a second positive terminal and a second negative terminal; the second positive terminal of the switch circuit is connected to the positive terminal of an external sodium ion battery PACK1; the second negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK1; the switch circuit is also provided with a third The third positive terminal of the switch circuit is connected to the positive terminal of the external sodium ion battery PACK2; the third negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK2; the voltage sensor is arranged at the first positive terminal and the first negative terminal of the switch circuit, and is connected to the main control BCM; the main control BCM is respectively connected to the soft start circuit, the filter circuit, the Hall sensor and the switch circuit to control the switch circuit so that the external sodium ion battery PACK1 and the external sodium ion battery PACK2 are switched between parallel and series states, and at the same time, the filter capacity level of the filter circuit is adjusted according to the change of the series-parallel connection state between the external sodium ion battery PACK1 and the external sodium ion battery PACK2, so as to smooth the current and voltage mutations caused by the series-parallel switching of the external sodium ion batteries in different states, and avoid the impact on the external energy storage PCS during the switching process.

[0023] Since the withstand voltage of common MOS (metal-oxide-semiconductor field-effect transistor) and IGBT (insulated gate bipolar transistor) is within 1200V, the voltage of the DC side of the energy storage converter PCS is generally between 500V and 1100V, and the full SOC voltage range of sodium-ion battery is between 1.5V and 4V. When the battery cluster is grouped in 334S, the battery cluster voltage range is 501~1336V, which exceeds the current energy storage converter PCS DC side accessible voltage range of 1100V. When the battery cluster is grouped in less than 334S, the minimum voltage of the battery cluster is lower than the DC side accessible voltage range of the energy storage converter PCS.

[0024] Therefore, in this application, based on the traditional high-voltage box, it is based on the wide voltage characteristics of sodium-ion energy storage batteries, uninterrupted power supply and rapid protection requirements of energy storage systems. The high-voltage box uses the main control BCM as the control center. According to the collected battery status data, the operating status of the energy storage system and the upper system control request, it controls the on and off of the switch circuit and cooperates with the voltage and current conversion of the external energy storage PCS to achieve nanosecond-level seamless switching of high and low voltages of the battery cluster. Different LC circuit groups in the filter circuit are configured to smooth the current and voltage mutations caused by the series-parallel switching of external sodium-ion batteries in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process. Under the premise that the existing external energy storage PCS converter is not modified, the voltage-adjustable high-voltage box is used to achieve efficient and low-cost seamless access to the wide voltage range sodium-ion energy storage system.

[0025] In specific implementation, Figure 2 As shown, the switch circuit includes a switch DCSSR1, a switch DCSSR2 and a switch DCSSR3; the first positive terminal of the switch circuit is directly led out as the second positive terminal of the switch circuit; the first positive terminal of the switch circuit is connected in series with the switch DCSSR3 to serve as the third positive terminal of the switch circuit; the first negative terminal of the switch circuit is directly led out as the third negative terminal of the switch circuit; the first negative terminal of the switch circuit is connected in series with the switch DCSSR2 to serve as the second negative terminal of the switch circuit; the switch DCSSR1 is connected in series between the second negative terminal of the switch circuit and the third positive terminal of the switch circuit; the master control BCM is connected to the switch DCSSR1, the switch DCSSR2 and the switch DCSSR3 to control the on / off state of each switch.

[0026] In a specific implementation, the filter circuit includes a first LC circuit and a second LC circuit; the first LC circuit and the second LC circuit are connected in parallel.

[0027] In a specific implementation, the first LC circuit includes a switch K11, a switch K12, an inductor L1 and a capacitor C1; the second LC circuit includes a switch K21, a switch K22, an inductor L2 and a capacitor C2; the first end of the switch K11 is connected to the first end of the switch K12 and the first end of the inductor L1; the second end of the switch K12 is connected to the first end of the capacitor C1; the first end of the switch K21 is connected to the first end of the switch K22 and the first end of the inductor L2; the second end of the switch K22 is connected to the first end of the capacitor C2; the switch K11 The second end of the inductor L1 is connected to the second end of the inductor L2, and the connection point serves as the second positive terminal of the filter circuit; the second end of the capacitor C1 is connected to the second end of the capacitor C2, the second end of the capacitor C1 serves as the first negative terminal of the filter circuit, and the second end of the capacitor C2 serves as the second negative terminal of the filter circuit; the master control BCM is connected to the switch K11, the switch K12, the switch K21 and the switch K22 to control the filtering capability level state of the filter circuit.

[0028] In a specific implementation, the soft start circuit includes a relay K31, a relay K32 and a resistor R31; the first end of the relay K31 is connected to the first end of the resistor R31; the second end of the relay K31 is connected to the first end of the relay K32, and the connection point serves as the first end of the soft start circuit; the second end of the resistor R31 is connected to the second end of the relay K32, and the connection point serves as the second end of the soft start circuit; the soft start circuit is used to connect the relay K31 and the resistor R31 for pre-charging before the relay K32 of the main path is officially connected, so as to prevent excessive impact on the external sodium ion battery.

[0029] Furthermore, the external sodium-ion batteries PACK1 and PACK2 are grouped in the same manner, both being XPYS, that is, battery packs of Y sodium-ion cells connected in series and X to Y sodium-ion cells connected in series are connected in parallel.

[0030] Furthermore, the switch DCSSR1, the switch DCSSR2 and the switch DCSSR3 may use MOS tubes or IGBT tubes, or other electronic components that can achieve the same or better switching performance.

[0031] Furthermore, the switch K11, the switch K12, the switch K21 and the switch K22 may use MOS tubes or IGBT tubes, or may also use relays, or other electronic components that can achieve the same switching function.

[0032] Furthermore, the above-mentioned circuits are arranged on a circuit board, and the high-voltage box also includes a shell, and the circuit board is arranged in the shell.

[0033] like Figure 2 , 3 As shown in , 5 and 6, a switch QF is provided between the second positive terminal of the filter circuit and the first terminal of the soft-start circuit; a switch QF is provided between the second negative terminal of the filter circuit and the Hall sensor.

[0034] In the present application, the soft-start circuit realizes the flexible access of the high-voltage box power supply, and the Hall sensor collects the main circuit current signal of the high-voltage box. The battery master control BCM collects the voltage and current signals of the main circuit, receives the battery slave control BMM information and the upper EMS and external energy storage PCS information and control signals, and feeds back the battery status information and control signals to the upper EMS and external energy storage PCS. According to the collected information and control signals, logical judgment is made and the soft-start circuit relay is controlled to be attracted, the filter circuit switch group is attracted, and the DC solid-state switch DCSSR of the switch circuit is turned on and off. Different LC circuit groups are configured in the filter circuit to smooth the current and voltage mutations caused by the series-parallel switching of the external sodium-ion battery in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process. The master control BCM controls the on and off of the DC solid-state switch DCSSR to cooperate with the voltage and current conversion of the external energy storage PCS to realize the seamless switching of the battery cluster voltage between high and low voltage.

[0035] Embodiment 2 like Figure 3 As shown, the difference between this embodiment and the first embodiment is that the switch circuit further includes a NOT gate N1; the input end of the NOT gate N1 is connected to the control end of the switch DCSSR2 and the control end of the switch DCSSR3; the input end of the NOT gate N1 is connected to the main control BCM; the output end of the NOT gate N1 is connected to the control end of the switch DCSSR1. The NOT gate N1 can realize the interlocking of the series mode and the parallel mode of the battery, that is, when the series mode is used, the parallel mode will not appear, and when the parallel mode is used, the series mode will not appear, so as to prevent the switches DCSSR1, DCSSR2, and DCSSR3 from being fully turned on at the same time due to the failure of the main control BCM or the wrong signal output setting, causing the battery and the external energy storage PCS to short-circuit, thereby increasing the safety performance of the circuit.

[0036] In a specific implementation, it also includes a first linkage circuit; the first linkage circuit includes an OR gate N2, a resistor R32 and a resistor R34; the first end of the resistor R32 is connected to the first end of the resistor R34, and the connection point is connected to the first input end of the OR gate N2; the second end of the resistor R34 is grounded; the second end of the resistor R32 is connected to the first end of the resistor R31; the second end input end of the OR gate N2 is connected to the master control BCM; the output end of the OR gate N2 is respectively connected to the switch K21 and the switch K22.

[0037] By linking the soft start circuit and the filter circuit through the first linkage circuit, it is possible to: Smooth start: The soft start circuit can gradually increase the current when the system starts, avoiding sudden high current shocks. The filter circuit can further smooth the current and reduce current ripples and spikes.

[0038] Protection circuit: Through the linkage of soft start circuit and filter circuit, the current impact at startup can be effectively reduced and other components in the circuit, such as capacitors, inductors and semiconductor devices, can be protected.

[0039] Improve system stability: The linkage between the soft-start circuit and the filter circuit can ensure that the current and voltage changes of the system are smoother during startup, reducing system oscillation and instability.

[0040] In a specific implementation, it also includes a second linkage circuit; the second linkage circuit includes a transistor N3, a capacitor C3 and a resistor R33; the collector of the transistor N3 is connected to the power supply VCC, the base is connected to the output end of the NOT gate N1, and the emitter is connected to the first end of the capacitor C3; the second end of the capacitor C3 is connected to the first end of the resistor R33, and the connection point is connected to the third input end of the OR gate N2; the second end of the resistor R33 is grounded.

[0041] By linking the switch circuit and the filter circuit through the second linkage circuit, it is possible to: Optimize current distribution: The switch circuit controls the connection mode of the battery pack (parallel or series), and the filter circuit can smooth the current changes when the switch circuit is switched, thereby optimizing the current distribution.

[0042] Reduce current shock: When the switch circuit is switched, adapting the corresponding filter circuit capacity level (for example, the series cut-in voltage is higher and two LC circuits are dynamically adjusted) can reduce the sudden change of current and avoid the impact on the energy storage system and PCS (power conversion system).

[0043] Improve system response speed: Through the linkage of switching circuits and filtering circuits, the system can respond to changes in state more quickly and improve the dynamic performance of the system.

[0044] At the same time, the linkage effect achieved by the hardware circuit in this application can improve the anti-interference ability and fault tolerance ability, and prevent the linkage failure problem caused by the failure of the upper controller. Even if the main control BCM fails, it will not affect the linkage protection effect.

[0045] Therefore, through the linkage circuit, not only the system reliability is improved, but also the linkage of the soft start circuit and the filter circuit, as well as the linkage of the switch circuit and the filter circuit, can significantly improve the reliability and stability of the system and reduce the probability of failure. It can also extend the life of the equipment, reduce current shocks and voltage fluctuations, and extend the service life of battery packs, capacitors, inductors and other key components. At the same time, the system performance is optimized. By smoothing the current and voltage changes, the overall performance of the system can be optimized, the energy conversion efficiency can be improved, and the energy loss can be reduced. It also improves the system's anti-interference ability and fault tolerance. It can significantly improve the stability and reliability of the energy storage system, reduce current shocks and voltage fluctuations, optimize system performance, and extend the life of the equipment. These improvements are of great significance to improving the overall performance and safety of the energy storage system.

[0046] Embodiment 3 like Figure 1 , Figure 4 As shown, a sodium ion energy storage system includes the above-mentioned high-voltage box suitable for the sodium ion energy storage system, and also includes an external energy storage PCS, a slave control BMM, an energy management system EMS, an external sodium ion battery PACK1 and an external sodium ion battery PACK2; the first positive terminal and the first negative terminal of the filter circuit are respectively connected to the positive terminal and the negative terminal of the external energy storage PCS; the second positive terminal and the second negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK1; the third positive terminal and the third negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK2; the master control BCM is respectively connected to the external energy storage PCS, the slave control BMM and the energy management system EMS.

[0047] Embodiment 4 A sodium ion energy storage system control method is used to control the sodium ion energy storage system described above, comprising the following steps: The high-voltage box performs a self-test after power-on. The main control BCM switches the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2 in series or in parallel, and records the voltage values ​​of the series or in parallel. When the series voltage value is greater than the maximum voltage of the external energy storage PCS DC side and the parallel voltage is less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to be disconnected, the switches DCSSR2 and DCSSR3 to be turned on, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the parallel buck mode; When the series voltage value is greater than the minimum voltage of the external energy storage PCS DC side and less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to turn on, the switch DCSSR2 and the switch DCSSR3 to turn off, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the series operation boost mode; When the series voltage value is less than the minimum voltage of the external energy storage PCS DC side, the main control BCM sends a charge and discharge prohibition instruction to the external energy storage PCS and the energy management system EMS, reporting a total voltage undervoltage fault; In the case of charging, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft start circuit to perform charging soft start in the manner of pre-charging first and then formal charging to prevent the impact damage to the battery caused by large current, and adjusts the series and parallel connection according to the battery voltage; In the discharge situation, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft-start circuit to perform discharge soft-start in the manner of pre-discharge first and then formal discharge to prevent large current from causing impact damage to the external energy storage PCS, and adjusts the series and parallel connection according to the battery voltage.

[0048] That is, let the total pressure of the external sodium ion battery PACK1 be Vp1 and the total pressure of the external sodium ion battery PACK2 be Vp2.

[0049] When Vp1+Vp2>PCS DC side maximum voltage Vmax and Vp1<Vmax&Vp2<Vmax, the master BCM controls DCSSR1 to disconnect, switches DCSSR2 and DCSSR3 to turn on, and PACK1 and PACK2 enter parallel buck mode, such as Figure 6 At this time, the main control BCM control switches K11, K12, K21, and K22 are energized, and the relays K31 and K32 of the control soft start circuit are energized in sequence to connect the external sodium ion battery to the PCS DC side.

[0050] When the master BCM detects that the minimum voltage Vmin≤Vp1+Vp2≤Vmax of the PCS DC side, the master BCM controls DCSSR1 to turn on, DCSSR2 and DCSSR3 to turn off, and PACK1 and PACK2 enter the series operation boost mode, such as Figure 5 The master BCM controls switches K11, K12, K21, and K22 to close, and relays K31 and K32 of the control soft-start circuit are closed in sequence to connect the external sodium-ion battery to the DC side of the PCS.

[0051] When the master BCM detects that Vmin is less than Vp1 + Vp2, the master BCM sends a charge and discharge prohibition instruction to the PCS and EMS, and reports a total voltage undervoltage fault.

[0052] During the charging process, if any cell voltage Vc in the energy storage system is ≥4.0V (the maximum voltage of the battery cell, which can be obtained by setting a voltage detection circuit or sensor for each cell and feeding back a signal to the main control BCM), or Vp1 ≥Vmax, or Vp2 ≥Vmax, the BCM will send a charging prohibition instruction to the PCS and EMS.

[0053] During the discharge process, when Vp1≤Vmin or Vp2≤Vmin, and any single cell voltage Vc in the energy storage system is greater than 1.5V, the main control BCM controls K11 and K12 to pull in, controls K21 and K22 to disconnect, and controls DCSSR1 to conduct after T1 time, and DCSSR2 and DCSSR3 to disconnect. After switching, the voltage of the battery cluster doubles and the current decreases by half. It is very easy for PCS devices to be damaged due to sudden voltage increase and current drop. The first LC circuit of the high-voltage box is for current flow and voltage regulation after switching. After switching, the BCM sends instructions to double the PCS voltage and reduce the current by half to adapt to the sudden change of the battery cluster voltage and current, so that PACK1 and PACK2 can seamlessly enter the series boost mode. If any single cell voltage Vc in the energy storage system is less than 1.5V, the BCM sends a prohibition instruction to the PCS and EMS. The T1 time is the interval time set according to actual needs.

[0054] During the discharge process, when the voltage of any cell in the energy storage system is Vc≤1.5V or Vp1+Vp2≤Vmin, the BCM sends a discharging prohibition instruction to the PCS and EMS.

[0055] During the charging process, when Vp1+Vp2≥Vmax, and any cell voltage Vc in the energy storage system is less than 4V, BCM controls K11 and K12 to disconnect, controls K21 and K22 to attract, and controls DCSSR1 to conduct after T2 time, and DCSSR2 and DCSSR3 to disconnect. After switching, the voltage of the battery cluster is reduced by one time, and the current is increased by one time. It is very easy for PCS devices to be damaged due to sudden voltage drop and sudden current increase. The second LC circuit of the high-voltage box is for current flow and voltage regulation after switching. After switching, BCM sends instructions to reduce the PCS voltage by one time and increase the current by one time to adapt to the sudden change of the voltage and current of the battery cluster, so that PACK1 and PACK2 can seamlessly enter the parallel buck mode. If any cell voltage Vc in the energy storage system is greater than or equal to 4V, or Vp1≥Vmax, or Vp2≥Vmax, BCM sends a charge prohibition instruction to PCS and EMS. The T2 time is the interval time set according to actual needs.

[0056] The high-voltage box of this solution can realize the connection of a wide voltage range sodium-ion energy storage system to a conventional PCS converter. It does not require the configuration of DCDC or the use of higher voltage platform power devices. It has the characteristics of low cost, high efficiency, fast switching speed and high reliability.

[0057] In situations where seamless switching is not required or switching time is not required, conventional circuit breakers, contactors, etc. can also be used to replace the DC solid-state switch DCSSR.

[0058] The present application provides a high-voltage box suitable for a sodium ion energy storage system, comprising: a soft start circuit, a filter circuit, a Hall sensor, a voltage sensor, a master control BCM and a switch circuit; the first positive terminal of the filter circuit is connected to the positive terminal of an external energy storage PCS; the first negative terminal of the filter circuit is connected to the negative terminal of the external energy storage PCS; the second positive terminal of the filter circuit is connected to the first end of the soft start circuit; the second end of the soft start circuit and the second negative terminal of the filter circuit are respectively connected to the first positive terminal and the first negative terminal of the switch circuit; the Hall sensor is connected in series between the second negative terminal of the filter circuit and the first negative terminal of the switch circuit; the switch circuit is also provided with a second positive terminal and a second negative terminal; the second positive terminal of the switch circuit is connected to the positive terminal of an external sodium ion battery PACK1; the second negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK1; the switch circuit is also provided with a third positive terminal The third positive terminal of the switch circuit is connected to the positive terminal of the external sodium ion battery PACK2; the third negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK2; the voltage sensor is arranged at the first positive terminal and the first negative terminal of the switch circuit, and is connected to the master control BCM; the master control BCM is respectively connected to the soft start circuit, the filter circuit, the Hall sensor and the switch circuit to control the switch circuit so that the external sodium ion battery PACK1 and the external sodium ion battery PACK2 are switched between parallel and series states, and the filter capacity level of the filter circuit is adjusted according to the change of the series-parallel connection state between the external sodium ion battery PACK1 and the external sodium ion battery PACK2, so as to smooth the current and voltage mutations generated by the series-parallel switching of the external sodium ion battery in different states, and avoid the impact on the external energy storage PCS during the switching process. Based on the traditional high-voltage box, it is based on the characteristics of the wide voltage of the sodium ion energy storage battery, the uninterrupted power supply and rapid protection requirements of the energy storage system. The high-voltage box uses the main control BCM as the control center. According to the collected battery status data, the operating status of the energy storage system and the control request of the upper system, it controls the on and off of the switch circuit and cooperates with the voltage and current transformation of the external energy storage PCS to achieve nanosecond-level seamless switching of the high and low voltages of the battery cluster. Different LC circuit groups in the filter circuit are configured to smooth the current and voltage mutations caused by the series-parallel switching of external sodium-ion batteries in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process. Under the premise of not changing the existing external energy storage PCS converter, the voltage-adjustable high-voltage box is used to achieve efficient, low-cost, wide-voltage range sodium-ion energy storage system seamless access.

[0059] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0060] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0061] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0062] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the present invention.

Claims

1. A high-voltage box suitable for a sodium ion energy storage system, characterized in that: include: Soft start circuit, filter circuit, Hall sensor, voltage sensor, main control BCM and switch circuit; The first positive terminal of the filter circuit is connected to the positive terminal of the external energy storage PCS; the first negative terminal of the filter circuit is connected to the negative terminal of the external energy storage PCS; the second positive terminal of the filter circuit is connected to the first end of the soft start circuit; the second end of the soft start circuit and the second negative terminal of the filter circuit are respectively connected to the first positive terminal and the first negative terminal of the switch circuit; the Hall sensor is connected in series between the second negative terminal of the filter circuit and the first negative terminal of the switch circuit; the switch circuit is also provided with a second positive terminal and a second negative terminal; the second positive terminal of the switch circuit is connected to the positive terminal of the external sodium ion battery PACK1; the second negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK1; the switch circuit is also provided with a third positive terminal and a third negative terminal; the third positive terminal of the switch circuit is connected to the external sodium ion battery PACK1; The positive terminal of the switch circuit is connected to the positive terminal of the external sodium ion battery PACK2; the third negative terminal of the switch circuit is connected to the negative terminal of the external sodium ion battery PACK2; the voltage sensor is arranged at the first positive terminal and the first negative terminal of the switch circuit, and is connected to the main control BCM; the main control BCM is respectively connected to the soft start circuit, the filter circuit, the Hall sensor and the switch circuit to control the switch circuit so that the external sodium ion battery PACK1 and the external sodium ion battery PACK2 are switched between parallel and series states, and at the same time, the filtering capacity level of the filter circuit is adjusted according to the change of the series-parallel connection state between the external sodium ion battery PACK1 and the external sodium ion battery PACK2, so as to smooth the current and voltage mutations generated by the series-parallel switching of the external sodium ion batteries in different states, smooth the current and voltage mutations, and avoid the impact on the external energy storage PCS during the switching process.

2. The high-voltage box suitable for the sodium ion energy storage system according to claim 1, characterized in that: The switch circuit includes switch DCSSR1, switch DCSSR2 and switch DCSSR3; the first positive terminal of the switch circuit is directly led out as the second positive terminal of the switch circuit; the first positive terminal of the switch circuit is connected in series with the switch DCSSR3 to serve as the third positive terminal of the switch circuit; the first negative terminal of the switch circuit is directly led out as the third negative terminal of the switch circuit; the first negative terminal of the switch circuit is connected in series with switch DCSSR2 to serve as the second negative terminal of the switch circuit; switch DCSSR1 is connected in series between the second negative terminal of the switch circuit and the third positive terminal of the switch circuit; the master control BCM is connected to the switch DCSSR1, switch DCSSR2 and switch DCSSR3 to control the on / off state of each switch.

3. The high-voltage box suitable for the sodium ion energy storage system according to claim 2, characterized in that: The switch circuit further comprises a NOT gate N1; the input end of the NOT gate N1 is connected to the control end of the switch DCSSR2 and the control end of the switch DCSSR3; the input end of the NOT gate N1 is connected to the main control BCM; the output end of the NOT gate N1 is connected to the control end of the switch DCSSR1.

4. The high-voltage box suitable for the sodium ion energy storage system according to claim 3, characterized in that: The filter circuit includes a first LC circuit and a second LC circuit; the first LC circuit and the second LC circuit are connected in parallel.

5. The high-voltage box suitable for the sodium ion energy storage system according to claim 4, characterized in that: The first LC circuit includes a switch K11, a switch K12, an inductor L1 and a capacitor C1; the second LC circuit includes a switch K21, a switch K22, an inductor L2 and a capacitor C2; a first end of the switch K11 is connected to a first end of the switch K12 and a first end of the inductor L1; a second end of the switch K12 is connected to a first end of the capacitor C1; a first end of the switch K21 is connected to a first end of the switch K22 and a first end of the inductor L2; a second end of the switch K22 is connected to a first end of the capacitor C2; a first end of the switch K11 is connected to a first end of the inductor L2 and a first end of the inductor L2; a second end of the switch K22 is connected to a first end of the capacitor C2; a first end of the switch K11 is connected to a first end of the inductor L2 and a first end of the inductor L2; a second end of the switch K22 is connected to a first end of the capacitor C2; a first end of the switch K11 is connected to a first end of the inductor L2 and a first end of the inductor L2; a second end of the switch K22 is connected to a first end of the capacitor C2; a first end of the switch K11 is connected to a first end of the inductor L2 and a first end of the inductor L2; a first end of the switch K1 ... inductor L2 and a first end of the inductor L2; The two ends are connected to the second end of the switch K21, and the connection point serves as the first positive terminal of the filter circuit; the second end of the inductor L1 is connected to the second end of the inductor L2, and the connection point serves as the second positive terminal of the filter circuit; the second end of the capacitor C1 is connected to the second end of the capacitor C2, the second end of the capacitor C1 serves as the first negative terminal of the filter circuit, and the second end of the capacitor C2 serves as the second negative terminal of the filter circuit; the master control BCM is connected to the switch K11, the switch K12, the switch K21 and the switch K22 to control the filtering capability level state of the filter circuit.

6. The high-voltage box suitable for the sodium ion energy storage system according to claim 5, characterized in that: The soft start circuit includes a relay K31, a relay K32 and a resistor R31; the first end of the relay K31 is connected to the first end of the resistor R31; the second end of the relay K31 is connected to the first end of the relay K32, and the connection point serves as the first end of the soft start circuit; the second end of the resistor R31 is connected to the second end of the relay K32, and the connection point serves as the second end of the soft start circuit; the soft start circuit is used to connect the relay K31 and the resistor R31 for pre-charging before the relay K32 of the main path is officially connected, so as to prevent excessive impact on the external sodium ion battery.

7. The high-voltage box suitable for the sodium ion energy storage system according to claim 6, characterized in that: It also includes a first linkage circuit; the first linkage circuit includes an OR gate N2, a resistor R32 and a resistor R34; the first end of the resistor R32 is connected to the first end of the resistor R34, and the connection point is connected to the first input end of the OR gate N2; the second end of the resistor R34 is grounded; the second end of the resistor R32 is connected to the first end of the resistor R31; the second end input end of the OR gate N2 is connected to the master control BCM; the output end of the OR gate N2 is respectively connected to the switch K21 and the switch K22.

8. The high-voltage box suitable for the sodium ion energy storage system according to claim 7, characterized in that: It also includes a second linkage circuit; the second linkage circuit includes a transistor N3, a capacitor C3 and a resistor R33; the collector of the transistor N3 is connected to the power supply VCC, the base is connected to the output end of the NOT gate N1, and the emitter is connected to the first end of the capacitor C3; the second end of the capacitor C3 is connected to the first end of the resistor R33, and the connection point is connected to the third input end of the OR gate N2; the second end of the resistor R33 is grounded.

9. A sodium ion energy storage system, characterized in that: It comprises a high-voltage box suitable for a sodium ion energy storage system as described in any one of claims 1 to 8, and also comprises an external energy storage PCS, a slave control BMM, an energy management system EMS, an external sodium ion battery PACK1 and an external sodium ion battery PACK2; the first positive terminal and the first negative terminal of the filter circuit are respectively connected to the positive terminal and the negative terminal of the external energy storage PCS; the second positive terminal and the second negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK1; the third positive terminal and the third negative terminal of the switch circuit are respectively connected to the positive and negative terminals of the external sodium ion battery PACK2; the master control BCM is respectively connected to the external energy storage PCS, the slave control BMM and the energy management system EMS.

10. A sodium ion energy storage system control method, characterized in that: Used to control the sodium ion energy storage system according to claim 9, comprising the following steps: The high-voltage box performs a self-test after power-on. The main control BCM switches the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2 in series or in parallel, and records the voltage values ​​of the series or in parallel. When the series voltage value is greater than the maximum voltage of the external energy storage PCS DC side and the parallel voltage is less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to be disconnected, the switches DCSSR2 and DCSSR3 to be turned on, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the parallel buck mode; When the series voltage value is greater than the minimum voltage of the external energy storage PCS DC side and less than the maximum voltage of the external energy storage PCS DC side, the main control BCM controls the switch DCSSR1 to turn on, the switch DCSSR2 and the switch DCSSR3 to turn off, and the external sodium ion battery PACK1 and the external sodium ion battery PACK2 enter the series operation boost mode; When the series voltage value is less than the minimum voltage of the external energy storage PCS DC side, the main control BCM sends a charge and discharge prohibition instruction to the external energy storage PCS and the energy management system EMS, reporting a total voltage undervoltage fault; In the case of charging, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft start circuit to perform charging soft start in the manner of pre-charging first and then formal charging to prevent the impact damage to the battery caused by large current, and adjusts the series and parallel connection according to the battery voltage; In the discharge situation, after the main control BCM adjusts the series or parallel connection mode of the external sodium-ion battery PACK1 and the external sodium-ion battery PACK2, it controls the soft-start circuit to perform discharge soft-start in the manner of pre-discharge first and then formal discharge to prevent large current from causing impact damage to the external energy storage PCS, and adjusts the series and parallel connection according to the battery voltage.

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