Charging and discharging double-loop circuit, charging and discharging control system and method and industrial and commercial energy storage system

Abstract

The invention provides a charging and discharging double-loop circuit, a charging and discharging control system and method and an industrial and commercial energy storage system, and belongs to the technical field of energy storage systems. The charging and discharging double-loop circuit comprises a charging loop and a discharging loop, the charging loop comprises a first normally open contact switch, a short circuit protection unit and a first diode, and the discharging loop comprises a second normally open contact switch, a short circuit protection unit and a second diode. Wherein the first normally open contact switch is arranged on the positive electrode line, the second normally open contact switch is arranged on the negative electrode line, and the charging loop and the discharging loop share the short circuit protection unit, so that the on-off of the charging circuit or the discharging circuit can be realized only by controlling the on-off of the first normally open contact switch and the second normally open contact switch. Compared with an existing charging and discharging circuit, the charging and discharging circuit has the advantages of being simple in circuit, convenient to wire, simple in logic control, low in cost and small in size.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage systems, and in particular to a charge-discharge dual-circuit circuit, a charge-discharge control system, a method, and an industrial and commercial energy storage system. Background Art

[0002] At present, the charge and discharge control circuits commonly used in industrial and commercial energy storage systems are Figure 1 As shown, a charging relay KM1, a discharging relay KM2, a diode VD1 and a diode VD2 are provided on the positive line of the circuit, a main negative relay KM3 is provided on the negative line of the circuit, and a fuse FUSE, a current sampling component HALL and a circuit breaker QF are also provided in the circuit.

[0003] It can be seen that in the existing charge and discharge control circuit, the BMS (battery management system) main control module needs to control the closing and opening of the charging relay KM1, the discharging relay KM2, and the main negative relay KM3. The control logic is relatively complex and three relays need to be configured. The wiring is relatively cumbersome and occupies a large space. Summary of the Invention

[0004] The main purpose of the embodiments of the present application is to propose a dual-circuit charge and discharge circuit, a charge and discharge control system, a method and an industrial and commercial energy storage system, aiming to achieve a dual-circuit charge and discharge circuit by only controlling the opening and closing of a first normally open contact switch and a second normally open contact switch, with the characteristics of simple circuit, convenient wiring, simple logical control, low cost and small size.

[0005] To achieve the above objectives, a first aspect of an embodiment of the present application provides a dual-circuit charge-discharge circuit for use in an industrial and commercial energy storage system, comprising:

[0006] A charging circuit includes a first normally open contact switch, a short-circuit protection unit, and a first diode, wherein the first end of the first normally open contact switch is used to connect to the energy storage converter of the commercial energy storage system, the second end of the first normally open contact switch is used to connect to the positive electrode of the battery cell of the commercial energy storage system, the negative electrode of the battery cell is connected to the first end of the short-circuit protection unit, the second end of the short-circuit protection unit is connected to the positive electrode of the first diode, and the negative electrode of the first diode is used to connect to the energy storage converter;

[0007] A discharge circuit, comprising a second normally open contact switch, the short-circuit protection unit, and a second diode, wherein the first end of the second normally open contact switch is used to connect to the energy storage converter, the second end of the second normally open contact switch is connected to the second end of the short-circuit protection unit, the first end of the short-circuit protection unit is connected to the negative electrode of the battery cell, the positive electrode of the battery cell is connected to the positive electrode of the second diode, and the negative electrode of the second diode is used to connect to the energy storage converter;

[0008] The second diode is connected in parallel to both ends of the first normally open contact switch, the first diode is connected in parallel to both ends of the second normally open contact switch, and the charging circuit and the discharging circuit share the short-circuit protection unit.

[0009] In one embodiment of the present application, when the battery cell is overvoltage, the first normally open contact switch is in an open state and the second normally open contact switch is in a closed state, so that the charging circuit is disconnected and the discharging circuit is connected;

[0010] When the battery cell is undervoltage, the first normally open contact switch is in a closed state and the second normally open contact switch is in an open state, so that the charging circuit is connected and the discharging circuit is disconnected;

[0011] When a short circuit occurs in the circuit, the short circuit protection unit is in an off state to disconnect the charging circuit and the discharging circuit.

[0012] In one embodiment of the present application, the charging and discharging dual-circuit circuit further includes an overload protection unit, and the charging circuit and the discharging circuit share the overload protection unit;

[0013] When the circuit is overloaded, the overload protection unit is in a disconnected state to disconnect the charging circuit and the discharging circuit.

[0014] In one embodiment of the present application, the overload protection unit is connected between the second end of the first normally open contact switch and the positive electrode of the battery unit;

[0015] Alternatively, the overload protection unit is connected between the first end of the first normally open contact switch and the energy storage converter;

[0016] Alternatively, the overload protection unit is connected between the first end of the second normally open contact switch and the energy storage converter;

[0017] Alternatively, the overload protection unit is connected between the second end of the second normally open contact switch and the second end of the short circuit protection unit;

[0018] Alternatively, the overload protection unit is connected between the first end of the short circuit protection unit and the negative electrode of the battery unit.

[0019] In one embodiment of the present application, the overload protection unit includes a power-off safety protection switch, which is connected between the second end of the first normally open contact switch and the positive pole of the battery cell, or the power-off safety protection switch is connected between the first end of the first normally open contact switch and the energy storage converter, or the power-off safety protection switch is connected between the first end of the second normally open contact switch and the energy storage converter, or the power-off safety protection switch is connected between the second end of the second normally open contact switch and the second end of the short-circuit protection unit, or the power-off safety protection switch is connected between the first end of the short-circuit protection unit and the negative pole of the battery cell; the power-off safety protection switch is used to disconnect the charging circuit and the discharging circuit when the circuit is overloaded.

[0020] To achieve the above objectives, a second aspect of an embodiment of the present application provides a charge and discharge control system, which is applied to an industrial and commercial energy storage system, comprising:

[0021] The charge-discharge dual-circuit circuit described in any embodiment of the present application;

[0022] A main control module is electrically connected to the first normally open contact switch and the second normally open contact switch in the charge and discharge dual-circuit circuit to control the on and off of the charging circuit and the discharging circuit.

[0023] In one embodiment of the present application, the main control module is also electrically connected to the overload protection unit in the charge-discharge dual-circuit circuit to control the on and off of the overload protection unit.

[0024] To achieve the above objectives, a third aspect of the embodiments of the present application provides a charge and discharge control method for controlling the charge and discharge dual-circuit circuit described in any embodiment of the present application, comprising:

[0025] When the battery cell is detected to be over-voltage, the first normally open contact switch is controlled to be disconnected and the second normally open contact switch is closed, so as to control the charging circuit to be disconnected and the discharging circuit to be connected;

[0026] When the battery cell is detected to be undervoltage, the first normally open contact switch is controlled to be closed and the second normally open contact switch is controlled to be open, so as to control the charging circuit to be connected and the discharging circuit to be disconnected.

[0027] In one embodiment of the present application, the method further includes:

[0028] When a circuit overload is detected, controlling the overload protection unit to disconnect, so as to disconnect the charging circuit and the discharging circuit;

[0029] Alternatively, when it is detected that the temperature of the battery cell is lower than a first preset temperature or higher than a second preset temperature, the first normally open contact switch is controlled to be disconnected and the second normally open contact switch is controlled to be closed, so as to control the charging circuit to be disconnected and the discharging circuit to be connected.

[0030] To achieve the above objectives, a fourth aspect of the embodiments of the present application provides an industrial and commercial energy storage system, including:

[0031] Battery cells, used for charging, discharging and storing electrical energy;

[0032] Energy storage converter, used for mutual conversion between AC and DC;

[0033] The charge-discharge dual-circuit circuit described in any embodiment of the present application;

[0034] A battery management system, comprising a main control module, configured to monitor and manage the operating status of the battery cells;

[0035] Energy management systems, which are used to dispatch and manage energy flows throughout the industrial and commercial energy storage system to ensure optimal energy efficiency;

[0036] Among them, the energy management system is connected to the battery management system and the energy storage inverter respectively, the charge and discharge dual-circuit circuit is connected between the battery unit and the energy storage inverter, and the main control module is electrically connected to the first normally open contact switch and the second normally open contact switch in the charge and discharge dual-circuit circuit to control the on and off of the charging circuit and the discharging circuit.

[0037] In the technical solution provided in the embodiment of the present application, the dual-circuit charging and discharging circuit includes a charging circuit and a discharging circuit, wherein the charging circuit includes a first normally open contact switch, a short-circuit protection unit and a first diode, and the discharging circuit includes a second normally open contact switch, a short-circuit protection unit and a second diode. The first normally open contact switch is set on the positive line, the second normally open contact switch is set on the negative line, and the charging circuit and the discharging circuit share the short-circuit protection unit, so that the charging circuit or the discharging circuit can be turned on and off by simply controlling the opening and closing of the first normally open contact switch and the second normally open contact switch. Compared with the existing charging and discharging circuit, the use of one relay can be reduced, and it has the characteristics of simple circuit, convenient wiring, simple logic control, low cost and small size. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of the charge and discharge control circuit commonly used in industrial and commercial energy storage systems.

[0039] Figure 2 This is a schematic diagram of the structure of the charging and discharging dual-loop circuit provided in Example 1 of the present application.

[0040] Figure 3 This is a schematic diagram of the charging circuit provided in Example 1 of the present application.

[0041] Figure 4 This is a schematic diagram of the discharge circuit provided in Example 1 of the present application.

[0042] Figure 5 This is a schematic diagram of the structure of the charging and discharging dual-loop circuit provided in Example 2 of the present application.

[0043] Figure 6 This is a schematic diagram of the charging circuit provided in Example 2 of the present application.

[0044] Figure 7 This is a schematic diagram of the discharge circuit provided in Example 2 of the present application.

[0045] Figure 8 It is a structural diagram of a charge and discharge control system provided in one embodiment of the present application.

[0046] Figure 9 This is a flow chart of a charge and discharge control method provided in one embodiment of the present application.

[0047] Figure 10 It is a structural diagram of an industrial and commercial energy storage system provided in one embodiment of the present application.

[0048] Reference numerals:

[0049] 110. Battery cell, 120. Energy storage converter, 130. Dual charge and discharge circuit, 131. Charging circuit, 132. Discharging circuit, 140. Battery management system, 141. Main control module, 150. Energy management system. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0051] It should be noted that although the device schematics illustrate functional module divisions and the flowcharts illustrate logical sequences, in certain circumstances, the steps shown or described may be performed in a sequence that differs from the module divisions in the device or the sequence in the flowcharts. The terms "first," "second," and so on, in the specification, claims, and drawings, are used to distinguish similar items and are not necessarily used to describe a specific sequence or precedence.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0053] At present, the charge and discharge control circuits commonly used in industrial and commercial energy storage systems are Figure 1 As shown, a charging relay KM1, a discharging relay KM2, a diode VD1 and a diode VD2 are provided on the positive line of the circuit, a main negative relay KM3 is provided on the negative line of the circuit, and a fuse FUSE, a current sampling component HALL and a circuit breaker QF are also provided in the circuit.

[0054] During the insulation test before powering on, the main negative relay KM3 must be opened to disconnect the negative line. Simultaneously, the charging relay KM1 and the discharge relay KM2 must be opened to disconnect the positive line. After powering on, if battery overvoltage is detected, the charging relay KM1 must be opened, and the discharge relay KM2 and the main negative relay KM3 must be closed, disconnecting the charging circuit and connecting the discharge circuit. If battery undervoltage is detected, the discharge relay KM2 must be opened, and the charging relay KM1 and the main negative relay KM3 must be closed, connecting the charging circuit and disconnecting the discharge circuit.

[0055] It can be seen that in the existing charge and discharge control circuit, the BMS (battery management system) main control module needs to control the closing and opening of the charging relay KM1, the discharging relay KM2, and the main negative relay KM3. The control logic is relatively complex and three relays need to be configured. The wiring is relatively cumbersome and occupies a large space.

[0056] Based on this, the present invention proposes a dual-circuit charging and discharging circuit. By placing a first normally-open contact switch on the positive line and a second normally-open contact switch on the negative line, and by sharing a short-circuit protection unit between the charging and discharging circuits, the charging and discharging circuits can be switched on and off simply by controlling the opening and closing of the first and second normally-open contact switches. Compared to existing charging and discharging circuits, this eliminates the need for one relay, resulting in a simple circuit, convenient wiring, straightforward logic control, low cost, and a compact size.

[0057] Example 1

[0058] Reference Figure 2-Figure 4 , Figure 2 This is a schematic diagram of the structure of the charge and discharge dual-circuit circuit provided in Example 1 of the present application. Figure 3 is a schematic diagram of a charging circuit provided in Example 1 of the present application, Figure 4 Schematic diagram of the discharge circuit provided in Example 1 of the present application. The charge and discharge dual circuit is applied to the industrial and commercial energy storage system. Figure 2 As shown, the dual-circuit charge-discharge circuit 130 includes a first normally-open contact switch KM1, a first diode D1, a second normally-open contact switch KM2, a second diode D2, and a short-circuit protection unit FUSE. The first end of the first normally-open contact switch KM1 is connected to the energy storage converter PCS, the second end of the first normally-open contact switch KM1 is connected to the positive electrode of the battery cell BAT, and the second diode D2 is connected in parallel across the first normally-open contact switch KM1. The negative electrode of the battery cell BAT is connected to the first end of the short-circuit protection unit FUSE, the second end of the short-circuit protection unit FUSE is connected to the second end of the second normally-open contact switch KM2, the first end of the second normally-open contact switch KM2 is connected to the energy storage converter PCS, and the first diode D1 is connected in parallel across the second normally-open contact switch KM2.

[0059] See also Figure 2 The charge and discharge dual loop circuit 130 shown in FIG. Figure 3 The charging circuit 131 shown and Figure 4 The discharge circuit 132 is shown.

[0060] Reference Figure 3 The charging circuit 131 includes a first normally open contact switch KM1, a short-circuit protection unit FUSE, and a first diode D1. The first end of the first normally open contact switch KM1 is connected to the energy storage converter PCS, the second end of the first normally open contact switch KM1 is connected to the positive electrode of the battery cell BAT, the negative electrode of the battery cell BAT is connected to the first end of the short-circuit protection unit FUSE, the second end of the short-circuit protection unit FUSE is connected to the positive electrode of the first diode D1, and the negative electrode of the first diode D1 is connected to the energy storage converter PCS.

[0061] Reference Figure 4 The discharge circuit 132 includes a second normally open contact switch KM2, a short-circuit protection unit FUSE, and a second diode D2. The first end of the second normally open contact switch KM2 is connected to the energy storage converter PCS, the second end of the second normally open contact switch PCS is connected to the second end of the short-circuit protection unit FUSE, the first end of the short-circuit protection unit FUSE is connected to the negative electrode of the battery cell BAT, the positive electrode of the battery cell BAT is connected to the positive electrode of the second diode D2, and the negative electrode of the second diode D2 is connected to the energy storage converter PCS.

[0062] The battery cells may include lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, etc. Under normal operating conditions, the first normally open contact switch KM1 and the second normally open contact switch KM2 are in a closed state, allowing the dual-circuit charge and discharge circuit 130 to operate on demand. For example, charging is performed during the off-peak electricity price range set by the power grid (such as 23:00-7:00) to reduce the operating cost of the energy storage system; while discharging is performed during the peak electricity price window of the power grid (such as 8:00-11:30, 14:00-17:00) to reduce electricity costs through peak-valley price arbitrage.

[0063] At the end of charging, if a battery cell overvoltage is detected, charging cannot continue. The first normally open contact switch KM1 is controlled to be open, thereby disconnecting the charging circuit 131 and terminating the charging process. At this time, if the battery cell needs to power an electrical load, that is, to discharge the battery cell, the second normally open contact switch KM2 is controlled to be closed, thereby connecting the discharge circuit.

[0064] At the end of discharge, if a battery cell undervoltage is detected, the battery cell cannot discharge. The second normally open contact switch KM2 is controlled to be open, thereby disconnecting the discharge circuit 132 and terminating the discharge process. At this point, if the battery cell needs to be charged to store energy, the first normally open contact switch KM1 is controlled to be closed, thereby connecting the charging circuit 131.

[0065] When a short circuit occurs in the circuit, the short-circuit protection unit FUSE is disconnected to cut off the current and protect the equipment. For example, when the current in the dual-circuit charge-discharge circuit 130 exceeds a set threshold (e.g., due to equipment failure or external short circuit), disconnecting the short-circuit protection unit FUSE can quickly cut off the circuit, thereby preventing critical equipment such as the battery unit BAT and the energy storage converter PCS from overheating and damage.

[0066] In this embodiment, by placing a first normally open contact switch KM1 on the positive line and a second normally open contact switch KM2 on the negative line, and by sharing a short-circuit protection unit FUSE between the charging circuit 131 and the discharging circuit 132, the charging circuit or the discharging circuit can be switched on and off simply by controlling the opening and closing of the first normally open contact switch KM1 and the second normally open contact switch KM2. Compared to the existing charging and discharging circuit 132, this eliminates the need for one relay, resulting in a simple circuit, convenient wiring, straightforward logic control, low cost, and compact size.

[0067] In some embodiments, the short-circuit protection unit FUSE includes a fuse or a fuse element. In other words, a fuse or a fuse element can be selected as the short-circuit protection unit FUSE. When a short circuit occurs in the circuit, the fuse element can disconnect the charging circuit 131 and the discharging circuit 132 by melting itself to provide short-circuit protection. When the current in the dual-circuit charge-discharge circuit 130 exceeds a set threshold (e.g., due to a device failure or external short circuit), the fuse element can quickly disconnect the circuit by melting, thereby preventing damage to critical devices such as the battery cells (BAT) and the energy storage converter (PCS) due to overheating. For example, if a short circuit occurs in the energy storage system during discharge, the fuse element can respond in milliseconds, blocking abnormal currents of several thousand amperes. Fuses also feature a simple structure and low cost. Similarly, when a short circuit occurs in the dual-circuit charge-discharge circuit 130, the fuse element can disconnect the fault current in milliseconds by melting, preventing damage to critical devices such as the battery cells (BAT) and the energy storage converter (PCS) due to overheating. Its melting speed exhibits a nonlinear relationship with current intensity: the higher the current, the shorter the melting time, making it suitable for the highly dynamic operating conditions of energy storage systems. Fuses operate entirely on physical thermal effects, requiring no external power or control signals, thus preventing protection gaps caused by electronic component failure. Similarly, fuses offer a simple structure and low manufacturing costs, and replacement and maintenance require only physical disassembly, eliminating the need for software debugging.

[0068] It should be noted that, in addition to fuses or fuses, the above-mentioned short-circuit protection unit FUSE may also use other devices with short-circuit protection functions (such as circuit breakers, overcurrent relays, etc.), which is not specifically limited in the embodiments of the present application.

[0069] In some embodiments, the first normally open contact switch KM1 includes a first relay, and the second normally open contact switch KM2 includes a second relay. This means that the first relay can be selected as the first normally open contact switch KM1, and the second relay can be selected as the second normally open contact switch KM2. Thus, the opening and closing of the first relay can control the on / off of the charging circuit 131, and the opening and closing of the second relay can control the on / off of the discharging circuit 132. The relays, driven by electromagnetic coils, completely isolate the low-voltage control circuit from the high-voltage dual-circuit charge-discharge circuit 130, preventing high-voltage interference with control signals and potential safety hazards. For example, the 5V / 12V low-voltage signal from a BMS (battery management system) can directly control the relay coil, indirectly managing the hundreds of volts of the battery dual-circuit charge-discharge circuit 130. Furthermore, the normally open contacts of the relays remain open when not in operation, ensuring that the dual-circuit charge-discharge circuit 130 is completely de-energized during non-operation, preventing leakage current from causing self-discharge or accidental activation of the battery pack. The relay uses an electromagnetic drive mechanism, which can achieve millisecond-level contact closing / opening speed, accurately adapt to charging and discharging start and stop instructions, and avoid energy loss or equipment impact caused by switching delays.

[0070] Example 2

[0071] Reference Figure 5-Figure 7 , Figure 5 This is a schematic diagram of the structure of the charging and discharging dual-circuit circuit provided in Example 2 of the present application. Figure 6 is a schematic diagram of a charging circuit provided in Example 2 of the present application, Figure 7 This is a schematic diagram of the discharge circuit provided in Example 2 of this application. Figure 5 As shown, the dual-circuit charge-discharge circuit 130 includes a first normally-open contact switch KM1, a first diode D1, a second normally-open contact switch KM2, a second diode D2, a short-circuit protection unit FUSE, and an overload protection unit SW. The first end of the first normally-open contact switch KM1 is connected to the energy storage converter PCS, the second end of the first normally-open contact switch KM1 is connected to the first end of the overload protection unit SW, the second end of the overload protection unit SW is connected to the positive electrode of the battery cell BAT, and the second diode D2 is connected in parallel across the first normally-open contact switch KM1. The negative electrode of the battery cell BAT is connected to the first end of the short-circuit protection unit FUSE, the second end of the short-circuit protection unit FUSE is connected to the second end of the second normally-open contact switch KM2, the first end of the second normally-open contact switch KM2 is connected to the energy storage converter PCS, and the first diode D1 is connected in parallel across the second normally-open contact switch KM2.

[0072] See also Figure 5 The charge and discharge dual loop circuit 130 shown in FIG. Figure 6 The charging circuit 131 shown and Figure 7 The discharge circuit 132 is shown.

[0073] Reference Figure 6 The charging circuit 131 includes a first normally open contact switch KM1, an overload protection unit SW, a short-circuit protection unit FUSE, and a first diode D1. The first end of the first normally open contact switch KM1 is connected to the energy storage converter PCS, the second end of the first normally open contact switch KM1 is connected to the first end of the overload protection unit SW, the second end of the overload protection unit SW is connected to the positive electrode of the battery cell BAT, the negative electrode of the battery cell BAT is connected to the first end of the short-circuit protection unit FUSE, the second end of the short-circuit protection unit FUSE is connected to the positive electrode of the first diode D1, and the negative electrode of the first diode D1 is connected to the energy storage converter PCS.

[0074] Reference Figure 7The discharge circuit 132 includes a second normally open contact switch KM2, a short-circuit protection unit FUSE, an overload protection unit SW, and a second diode D2. The first end of the second normally open contact switch KM2 is connected to the energy storage converter PCS, the second end of the second normally open contact switch PCS is connected to the second end of the short-circuit protection unit FUSE, the first end of the short-circuit protection unit FUSE is connected to the negative electrode of the battery cell BAT, the positive electrode of the battery cell BAT is connected to the second end of the overload protection unit SW, the first end of the overload protection unit SW is connected to the positive electrode of the second diode D2, and the negative electrode of the second diode D2 is connected to the energy storage converter PCS.

[0075] It should be noted that in the embodiment of the present application, the overload protection unit SW is disposed in the common portion of the charging circuit 131 and the discharging circuit 132, i.e., the charging circuit 131 and the discharging circuit 132 share the overload protection unit SW. Therefore, in addition to being disposed between the second end of the first normally-open contact switch KM1 and the positive electrode of the battery cell BAT, the overload protection unit SW can also be disposed, for example, between the negative electrode of the battery cell BAT and the first end of the short-circuit protection unit FUSE, or between the second end of the short-circuit protection unit FUSE and the second end of the second normally-open contact switch KM2, or between the first end of the second normally-open contact switch KM2 and the energy storage converter PCS, or between the first end of the first normally-open contact switch KM1 and the energy storage converter PCS. Thus, by controlling the on / off state of the overload protection unit SW, the on / off state of the charging circuit 131 and the discharging circuit 132 can be simultaneously controlled. Specifically, if the overload protection unit SW is controlled to be turned on, the charging circuit 131 and the discharging circuit 132 can be controlled to be turned on at the same time (the first normally open contact switch KM1 and the second normally open contact switch KM2 are closed); if the overload protection unit SW is controlled to be turned off, the charging circuit 131 and the discharging circuit 132 can be controlled to be turned off at the same time (the first normally open contact switch KM1 and the second normally open contact switch KM2 are closed).

[0076] In the embodiment of the present application, when the circuit is overloaded for a long time (such as being in an overload state for more than a preset time), the charging circuit 1312 and the discharging circuit 132 can be disconnected by controlling the overload protection unit SW to be in an off state to perform overload protection.

[0077] In the embodiment of the present application, the overload protection unit SW includes a power-off safety protection switch, that is, the power-off safety protection switch can be selected as the overload protection unit SW. Among them, when the power-off safety protection switch detects an abnormality such as an overload, the main control module of the battery management system can send a drive control signal to control the power-off safety protection switch to be disconnected, so as to block the spread of the fault current and avoid battery thermal runaway or damage to power devices. For example, in a battery short-circuit scenario, its disconnection speed is 2-3 times faster than that of a traditional circuit breaker, which can significantly reduce the risk of heat accumulation. At the same time, using a power-off safety protection switch instead of a circuit breaker can greatly reduce the volume occupied by the circuit.

[0078] It should be noted that, in addition to the power-off safety protection switch, the above-mentioned overload protection unit SW may also use other devices with overload protection functions (such as overload relays, etc.), which is not specifically limited in the embodiments of the present application.

[0079] In some embodiments, when the dual-circuit charge-discharge circuit 130 short-circuits, the short-circuit protection unit FUSE can cut off the current by melting itself to protect the device. Furthermore, when the dual-circuit charge-discharge circuit 130 is overloaded, such as if the dual-circuit charge-discharge circuit 130 remains overloaded for a set time (e.g., 20 seconds), the overload protection unit SW can be controlled to disconnect the charging circuit 131 and the discharging circuit 132 for maintenance. This ensures that the charging and discharging circuits are completely de-energized during maintenance, eliminating the risk of electric shock from residual voltage.

[0080] In the embodiment of the present application, by placing the first normally open contact switch KM1 on the positive line and the second normally open contact switch KM2 on the negative line, and by sharing the short-circuit protection unit FUSE and the overload protection unit SW between the charging circuit 131 and the discharging circuit 132, the charging circuit or the discharging circuit can be turned on and off simply by controlling the opening and closing of the first normally open contact switch KM1 and the second normally open contact switch KM2. Compared to the existing charging and discharging circuit 132, the use of one relay can be eliminated. At the same time, by sharing the short-circuit protection unit FUSE and the overload protection unit SW, the circuit is simplified, wiring is convenient, the logic control is simplified, the cost is reduced, and the size is reduced.

[0081] Reference Figure 8 , Figure 8 This is a schematic diagram of the structure of the charge and discharge control system provided by an embodiment of the present application. Figure 8As shown, the charge-discharge control system includes a main control module 141 and the dual-circuit charge-discharge circuit 130 provided in any embodiment of the present application. The first normally-open contact switch KM1 and the second normally-open contact switch KM2 in the dual-circuit charge-discharge circuit 130 are both electrically connected to the main control module 141. The main control module 141 can control the opening and closing of the first normally-open contact switch KM1 and the second normally-open contact switch KM2 to control the on / off of the charging circuit 131 and the discharging circuit 132. The main control module 141 can also be electrically connected to the overload protection unit SW to control the on / off of the overload protection unit SW. If the circuit is overloaded, the main control module 141 can control the overload protection unit SW to disconnect, thereby disconnecting the charging circuit 131 and the discharging circuit 132, thereby providing overload protection.

[0082] Specifically, under normal operating conditions, the overload protection unit SW, the first normally open contact switch KM1, and the second normally open contact switch KM2 are all in a closed state, allowing the charge-discharge dual-circuit circuit 130 to operate on demand. For example, during the off-peak electricity price period set by the power grid (e.g., 23:00-7:00), the main control module 141 controls the charge-discharge dual-circuit circuit 130 to charge (the charging circuit 131 is turned on and the discharge circuit 132 is turned off) to reduce the operating cost of the energy storage system; and during the peak electricity price window of the power grid (e.g., 8:00-11:30, 14:00-17:00), the main control module 141 controls the charge-discharge dual-circuit circuit 130 to discharge (the charging circuit 131 is turned off and the discharge circuit 132 is turned on) to reduce electricity costs through peak-valley price arbitrage. Among them, the overload protection unit SW is in a conducting state.

[0083] At the end of charging, when the main control module 141 detects an overvoltage in the battery cell BAT, charging cannot continue. The main control module 141 controls the overload protection unit SW to a normally closed state and the first normally open contact switch KM1 to an open state, thereby disconnecting the charging circuit 131 and terminating the charging process. At this point, if the battery cell BAT needs to power a load, that is, discharge the battery cell, the main control module 141 controls the second normally open contact switch KM2 to a closed state, thereby connecting the discharge circuit 132.

[0084] At the end of discharge, if a battery cell undervoltage is detected, discharging the battery cell is impossible. The main control module 141 controls the overload protection unit SW to a normally closed state and the second normally open contact switch KM2 to an open state, thereby disconnecting the discharge circuit 132 and terminating the discharge process. At this point, if the battery cell needs to be charged to store energy, the main control module 141 controls the first normally open contact switch KM1 to a closed state, thereby connecting the charging circuit 131.

[0085] When a short circuit occurs in the circuit, the short-circuit protection unit FUSE cuts off the current by melting itself to protect the equipment. It can cut off the circuit in milliseconds to ensure system safety.

[0086] When the circuit is overloaded (such as being in an overload state for more than a set time), the main control module 141 can send a pulse drive current to enable the power-off safety protection switch based on the satisfaction of the logical judgment conditions, cut off the current-carrying components in the component, and disconnect the charging circuit 131 and the discharging circuit 132 to ensure system safety.

[0087] In the embodiment of the present application, by setting the first normally open contact switch KM1 on the positive line and the second normally open contact switch KM2 on the negative line, the main control module 141 only needs to control the opening and closing of the first normally open contact switch KM1 and the second normally open contact switch KM2 to realize the on and off of the charging circuit 131 or the discharging circuit 132. At the same time, the charging circuit 131 and the discharging circuit 132 share the short-circuit protection unit FUSE and the overload protection unit SW. When the short-circuit protection unit FUSE is disconnected, the charging circuit 131 and the discharging circuit 132 are both disconnected to achieve short-circuit protection. The main control module 141 can disconnect the charging circuit 131 and the discharging circuit 132 to achieve overload protection by controlling the overload protection unit SW to be disconnected. Compared with the existing charge and discharge control system, the use of one relay can be reduced. At the same time, by sharing the short-circuit protection unit FUSE and the overload protection unit SW, the circuit is simplified, the wiring is convenient, the logic control is simplified, the cost is reduced, and the volume is reduced.

[0088] Reference Figure 9 , Figure 9 This is a flow chart of a charge and discharge control method provided in one embodiment of the present application, including but not limited to steps S910 to S920. This charge and discharge control method is used to control the dual-circuit charge and discharge circuit provided in any embodiment of the present application. This charge and discharge control method can be executed by the main control module 141 provided in an embodiment of the present application. The main control module 141 can be a PLC control module of the battery management system 140, or a microprocessor, single-chip microcomputer, etc., and is not specifically limited in this embodiment of the present application.

[0089] Step S910: When a battery cell overvoltage is detected, the first normally open contact switch is controlled to be open and the second normally open contact switch is controlled to be closed, so as to disconnect the charging circuit and connect the discharging circuit.

[0090] Step S920: When it is detected that the battery cell is undervoltage, the first normally open contact switch is controlled to be closed and the second normally open contact switch is controlled to be open, so as to control the charging circuit to be connected and the discharging circuit to be disconnected.

[0091] In this embodiment of the present application, by connecting the first normally open contact switch KM1 and the second normally open contact switch KM2 to the main control module 141, when the main control module 141 detects an overvoltage in the battery cell BAT, the main control module 141 controls the first normally open contact switch KM1 to open and the second normally open contact switch KM2 to close, thereby disconnecting the charging circuit 131 and connecting the discharging circuit 132. In this way, when the battery cell BAT is overvoltage and cannot continue charging, the charging circuit 131 can be disconnected to terminate the charging process.

[0092] When the main control module 141 detects an undervoltage in the battery cell BAT, it controls the first normally open contact switch KM1 to close and the second normally open contact switch KM2 to open, thereby connecting the charging circuit 131 and disconnecting the discharging circuit 132. This allows the discharging circuit 132 to be disconnected to terminate the discharging process when the battery cell BAT is undervoltage and cannot continue discharging.

[0093] At the same time, when a short circuit occurs in the circuit, the short-circuit protection unit FUSE can cut off the current by melting itself to protect the equipment. It can achieve millisecond-level circuit cutting to ensure system safety.

[0094] In some embodiments, the charge and discharge control method further includes the following steps:

[0095] When a circuit overload is detected, the overload protection unit is controlled to disconnect, so as to disconnect the charging circuit and the discharging circuit.

[0096] Alternatively, when it is detected that the temperature of the battery cell is lower than the first preset temperature or higher than the second preset temperature, the first normally open contact switch is controlled to be disconnected and the second normally open contact switch is controlled to be closed, so as to control the charging circuit to be disconnected and the discharging circuit to be connected.

[0097] In the embodiment of the present application, when the main control module 141 detects a circuit overload, the main control module 141 can control the overload protection unit SW to disconnect, thereby disconnecting the charging circuit 131 and the discharging circuit 132. In this way, when a circuit overload occurs, the charging and discharging dual circuits can be protected by controlling the overload protection unit SW to disconnect.

[0098] In an embodiment of the present application, when the main control module 141 detects that the temperature of the battery cell BAT is lower than the first preset temperature or higher than the second preset temperature, such as when it detects that the temperature of the battery cell BAT is lower than 0°C or higher than 60°C, the main control module 141 can control the overload protection unit SW to disconnect, so as to disconnect the charging circuit 131 and the discharging circuit 132, thereby avoiding the battery cell BAT continuing to charge and discharge when the temperature is too low or too high, thereby affecting the life of the battery cell. Taking the battery cell as a lithium battery as an example, at low temperatures (<0°C), the migration speed of lithium ions decreases, causing metallic lithium to accumulate on the surface of the negative electrode to form dendrites, which may pierce the diaphragm and cause a short circuit. Lithium precipitation will consume active lithium, causing a permanent decrease in battery capacity and a shortened cycle life. When the temperature is above 45°C, the rupture of the SEI film is accelerated, active lithium is continuously consumed, and the capacity loss in a single cycle is as much as 5%-10%. To prevent the battery cell BAT from being damaged, the main control module 141 can control the overload protection unit SW to disconnect when it detects that the temperature of the battery cell BAT is lower than a first preset temperature or higher than a second preset temperature, thereby disconnecting the charging circuit 131 and the discharging circuit 132. Specifically, by disconnecting the overload protection unit SW when the temperature is too low or too high, the battery cell BAT is prevented from being charged or discharged when the temperature is too high or too low.

[0099] In the embodiment of the present application, by electrically connecting the first normally open contact switch KM1, the second normally open contact switch KM2, and the overload protection unit SW in the charge-discharge dual-circuit circuit to the main control module 141, the main control module 141 can control the opening and closing of the first normally open contact switch KM1, the second normally open contact switch KM2, and the overload protection unit SW to control the opening and closing of the charging circuit 131 and the discharging circuit 132, thereby effectively controlling the charging and / or discharging process of the charge-discharge dual-circuit circuit. In addition, because the first normally open contact switch KM1 is set on the positive line and the second normally open contact switch KM2 is set on the negative line, the charging circuit 131 or the discharging circuit 132 can be turned on and off by simply controlling the opening and closing of the first normally open contact switch KM1 and the second normally open contact switch KM2. Compared with the existing charge and discharge control system, the use of one relay can be reduced. At the same time, by sharing the short-circuit protection unit FUSE and the overload protection unit SW, the circuit is simplified, the wiring is convenient, the logic control is simplified, the cost is reduced, and the volume is reduced.

[0100] Reference Figure 10 , Figure 10 This is a schematic diagram of the structure of the industrial and commercial energy storage system provided by an embodiment of the present application. Figure 10As shown, the industrial and commercial energy storage system includes a battery cell 110, an energy storage converter 120, a dual-circuit charge-discharge circuit 130 provided in any embodiment of the present application, a battery management system 140, and an energy management system 150. The battery management system 140 includes a main control module 141; the energy management system 150 is connected to the battery management system 140 and the energy storage converter 120, respectively. The dual-circuit charge-discharge circuit 130 is connected between the battery cell 110 and the energy storage converter 120. The main control module 141 is electrically connected to the first normally open contact switch KM1 and the second normally open contact switch KM2 in the dual-circuit charge-discharge circuit 130 to control the on / off of the charging circuit 131 and the discharging circuit 132.

[0101] Battery cells 110 are used for charging, discharging, and storing electrical energy. They are core components of industrial and commercial energy storage systems. Common battery cells 110 include lithium-ion batteries (such as lithium iron phosphate batteries) and lead-acid batteries. Lithium iron phosphate batteries have the advantages of high energy density, long cycle life, and good safety, and are increasingly used in industrial and commercial energy storage systems. Lead-acid batteries, on the other hand, are less expensive but have relatively poor energy density and cycle life.

[0102] The energy storage converter 120 is used for AC / DC conversion. During charging, it converts AC power to DC power to charge the battery pack. During discharging, it converts DC power from the battery pack to AC power to supply industrial and commercial equipment. The energy storage converter 120 also controls the power output of the industrial and commercial energy storage system, enabling flexible energy scheduling.

[0103] The Battery Management System (BMS) 140 monitors the battery status in real time, including state of charge (SOC), state of health (SOH), and temperature, to ensure efficient and safe battery operation. Specifically, the BMS 140 includes a main control module 141, which controls the on / off state of the charging circuit 131 and the discharging circuit 132 based on the battery's SOC and temperature.

[0104] The energy management system (EMS) 150 is used to dispatch and manage the energy flow of the entire industrial and commercial energy storage system to ensure optimal energy efficiency. Specifically, the energy management system (EMS) can formulate charging and discharging strategies based on multiple sources of information such as grid load and electricity price signals to ensure that the system achieves economic benefits while meeting power demand. The energy management system 150 is connected to the battery management system 140, so that the energy management system 150 can send corresponding instructions to the main control module 141 of the battery management system 140 based on the formulated charging and discharging strategy, so that the main control module 141 controls the on and off of the charging circuit 131 or the discharging circuit 132 according to the received instructions.

[0105] In an embodiment of the present application, the industrial and commercial energy storage system includes the dual-circuit charge-discharge circuit 130 provided in any embodiment of the present application, thereby enabling the industrial and commercial energy storage system to have the effects of the dual-circuit charge-discharge circuit 130, namely, by setting the first normally open contact switch KM1 on the positive line and the second normally open contact switch KM2 on the negative line, and the charging circuit 131 and the discharging circuit 132 sharing the short-circuit protection unit FUSE and the overload protection unit SW, so that the main control module 141 only needs to control the opening and closing of the first normally open contact switch KM1 and the second normally open contact switch KM2 to achieve the on-off of the charging circuit 131 or the discharging circuit 132. Compared with the existing charge and discharge control system, the use of one relay can be reduced. At the same time, by sharing the short-circuit protection unit FUSE and the overload protection unit SW, the circuit is simplified, the wiring is convenient, the logic control is simplified, the cost is reduced, and the volume is reduced.

[0106] The embodiments described in the embodiments of this application are intended to more clearly illustrate the technical solutions of the embodiments of this application and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0107] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0108] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, i.e., they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0109] Those skilled in the art will appreciate that all or some of the steps in the methods, systems, and functional modules / units in the devices disclosed above may be implemented as software, firmware, hardware, or appropriate combinations thereof.

[0110] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0111] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0113] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0114] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A dual-circuit charge and discharge circuit, used in industrial and commercial energy storage systems, characterized in that: include: A charging circuit includes a first normally open contact switch, a short-circuit protection unit, and a first diode, wherein the first end of the first normally open contact switch is used to connect to the energy storage converter of the commercial energy storage system, the second end of the first normally open contact switch is used to connect to the positive electrode of the battery cell of the commercial energy storage system, the negative electrode of the battery cell is connected to the first end of the short-circuit protection unit, the second end of the short-circuit protection unit is connected to the positive electrode of the first diode, and the negative electrode of the first diode is used to connect to the energy storage converter; A discharge circuit, comprising a second normally open contact switch, the short-circuit protection unit, and a second diode, wherein the first end of the second normally open contact switch is used to connect to the energy storage converter, the second end of the second normally open contact switch is connected to the second end of the short-circuit protection unit, the first end of the short-circuit protection unit is connected to the negative electrode of the battery cell, the positive electrode of the battery cell is connected to the positive electrode of the second diode, and the negative electrode of the second diode is used to connect to the energy storage converter; The second diode is connected in parallel to both ends of the first normally open contact switch, the first diode is connected in parallel to both ends of the second normally open contact switch, and the charging circuit and the discharging circuit share the short-circuit protection unit.

2. The charge-discharge dual-circuit circuit according to claim 1, characterized in that: When the battery cell is over-voltage, the first normally open contact switch is in an open state and the second normally open contact switch is in a closed state, so that the charging circuit is disconnected and the discharging circuit is connected; When the battery cell is undervoltage, the first normally open contact switch is in a closed state and the second normally open contact switch is in an open state, so that the charging circuit is connected and the discharging circuit is disconnected; When a short circuit occurs in the circuit, the short circuit protection unit is in an off state to disconnect the charging circuit and the discharging circuit.

3. The charge-discharge dual-circuit circuit according to claim 1, characterized in that: The charge-discharge dual-circuit circuit further includes an overload protection unit, which is shared by the charging circuit and the discharging circuit; When the circuit is overloaded, the overload protection unit is in a disconnected state to disconnect the charging circuit and the discharging circuit.

4. The charge-discharge dual-circuit circuit according to claim 3, characterized in that: The overload protection unit is connected between the second end of the first normally open contact switch and the positive electrode of the battery unit; Alternatively, the overload protection unit is connected between the first end of the first normally open contact switch and the energy storage converter; Alternatively, the overload protection unit is connected between the first end of the second normally open contact switch and the energy storage converter; Alternatively, the overload protection unit is connected between the second end of the second normally open contact switch and the second end of the short circuit protection unit; Alternatively, the overload protection unit is connected between the first end of the short circuit protection unit and the negative electrode of the battery unit.

5. The charge-discharge dual-circuit circuit according to claim 3 or 4, characterized in that: The overload protection unit includes a power-off safety protection switch, which is connected between the second end of the first normally open contact switch and the positive pole of the battery cell, or the power-off safety protection switch is connected between the first end of the first normally open contact switch and the energy storage converter, or the power-off safety protection switch is connected between the first end of the second normally open contact switch and the energy storage converter, or the power-off safety protection switch is connected between the second end of the second normally open contact switch and the second end of the short-circuit protection unit, or the power-off safety protection switch is connected between the first end of the short-circuit protection unit and the negative pole of the battery cell; the power-off safety protection switch is used to disconnect the charging circuit and the discharging circuit when the circuit is overloaded.

6. A charge and discharge control system, applied to industrial and commercial energy storage systems, characterized in that: include: The charge-discharge dual-circuit circuit according to any one of claims 1 to 5; A main control module is electrically connected to the first normally open contact switch and the second normally open contact switch in the charge and discharge dual-circuit circuit to control the on and off of the first normally open contact switch and the second normally open contact switch.

7. The charge and discharge control system according to claim 6, characterized in that: The main control module is also electrically connected to the overload protection unit in the charge and discharge dual-circuit circuit to control the on and off of the overload protection unit.

8. A charge and discharge control method for controlling the charge and discharge dual-circuit circuit according to any one of claims 1 to 5, characterized in that: include: When the battery cell is detected to be over-voltage, the first normally open contact switch is controlled to be disconnected and the second normally open contact switch is closed, so as to control the charging circuit to be disconnected and the discharging circuit to be connected; When the battery cell is detected to be undervoltage, the first normally open contact switch is controlled to be closed and the second normally open contact switch is controlled to be open, so as to control the charging circuit to be connected and the discharging circuit to be disconnected.

9. The method according to claim 8, characterized in that The method further comprises: When a circuit overload is detected, controlling the overload protection unit to disconnect, so as to disconnect the charging circuit and the discharging circuit; Alternatively, when it is detected that the temperature of the battery cell is lower than a first preset temperature or higher than a second preset temperature, the first normally open contact switch is controlled to be disconnected and the second normally open contact switch is controlled to be closed, so as to control the charging circuit to be disconnected and the discharging circuit to be connected.

10. An industrial and commercial energy storage system, characterized in that: include: Battery cells, used for charging, discharging and storing electrical energy; Energy storage converter, used for mutual conversion between AC and DC; The charge-discharge dual-circuit circuit according to any one of claims 1 to 5; A battery management system, comprising a main control module, configured to monitor and manage the operating status of the battery cells; Energy management systems, which are used to dispatch and manage energy flows throughout the industrial and commercial energy storage system to ensure optimal energy efficiency; In which, the energy management system is respectively connected to the battery management system and the energy storage inverter, the charge and discharge dual-circuit circuit is connected between the battery unit and the energy storage inverter, and the main control module is electrically connected to the first normally open contact switch and the second normally open contact switch in the charge and discharge dual-circuit circuit to control the on and off of the first normally open contact switch and the second normally open contact switch.

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