Energy storage system

Abstract

The utility model discloses an energy storage system. The system comprises at least one power supply branch, the power supply branch comprises at least one battery pack comprising an input end and an output end, and a high-voltage box comprising a first interface, a second interface, a third interface and a fourth interface, the first interface is electrically connected with the input end, the second interface is electrically connected with one output end, and the third interface and the fourth interface are electrically connected with target equipment respectively. The high-voltage box further comprises a first fuse and a first relay, the first fuse and the first relay are arranged between the first interface and the third interface, or the first fuse and the first relay are arranged between the second interface and the fourth interface, the first fusing current of the first fuse is not smaller than the first current and not larger than the second current, and the second fusing current of the second fuse is not smaller than the third current. The first disconnection current of the first relay is not smaller than the third current and not larger than the fourth current, and the fourth current is not smaller than the first current and smaller than the second current, so that the safety performance of the energy storage system is improved, the maintenance cost is reduced, and the safety performance of the system is improved.

Description

Technical Field

[0001] The present application relates to the field of battery power supply technology, and in particular to an energy storage system. Background Art

[0002] When a short circuit occurs in the power storage system, the lithium battery and other components in the power storage system will be greatly damaged. Therefore, the selection of protection devices in the power storage system is particularly important. Generally, the power storage system is protected from short circuit by setting a fuse in the high-voltage box. However, this method has low safety performance and cannot protect the power storage system from global faults. Utility Model Content

[0003] The embodiment of the present application provides an energy storage system, aiming to solve the technical problem of low safety of energy storage systems in the prior art.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] An energy storage system comprises at least one power supply branch, wherein the power supply branch comprises:

[0006] at least one battery pack including an input terminal and an output terminal;

[0007] A high voltage box, comprising a first interface, a second interface, a third interface and a fourth interface, wherein the first interface is electrically connected to the input end, the second interface is electrically connected to the output end, and the third interface and the fourth interface are electrically connected to the target device respectively;

[0008] Wherein, the high-voltage box further includes a first fuse and a first relay, the first fuse and the first relay are arranged between the first interface and the third interface, or the first fuse and the first relay are arranged between the second interface and the fourth interface;

[0009] The first fusing current of the first fuse is not less than a preset first current and not greater than a preset second current, the first disconnecting current of the first relay is not less than a preset third current and not greater than a preset fourth current, and the fourth current is not less than the first current and less than the second current.

[0010] In one embodiment, when the fault current of the power supply branch is greater than or equal to the first current and less than the fourth current, the fusing time of the first fuse is less than the disconnecting time of the first relay.

[0011] In one embodiment, each of the battery packs includes a second fuse and at least one battery cell, and the second fuse and at least one battery cell are connected in series and are respectively connected to the input end and the output end;

[0012] Or, each of the battery packs includes at least one second fuse and at least one battery cell, and the second fuse and the battery cell are connected in series one by one and are respectively electrically connected to the input end and the output end to achieve parallel connection;

[0013] The second fusing current of the second fuse is not less than a preset fifth current and not greater than a preset sixth current, and the fifth current is less than or equal to the fourth current and greater than or equal to the first current.

[0014] In one embodiment, in the power supply branch, the fusing speed of the first fuse is greater than the fusing speed of the second fuse.

[0015] In one embodiment, the high voltage box further comprises a third fuse;

[0016] Wherein, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse is arranged between the second interface and the fourth interface; or the first fuse and the first relay are arranged between the second interface and the fourth interface, and the third fuse is arranged between the first interface and the third interface;

[0017] A third fusing current of the third fuse is not less than the first current and not greater than the second current.

[0018] In one embodiment, the high voltage box further comprises a second relay;

[0019] Among them, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse and the second relay are arranged between the second interface and the fourth interface; the second disconnection current of the second relay is not less than the third current and not greater than the fourth current.

[0020] In one embodiment, the power supply branch includes a plurality of battery packs, and the plurality of battery packs are connected in series.

[0021] In one embodiment, the target device is an energy storage inverter; when the current of the power supply branch is not less than a preset seventh current and not greater than a preset eighth current, the energy storage inverter controls the battery pack in the power supply branch to stop charging and / or discharging; wherein the eighth current is less than or equal to the fourth current.

[0022] In one embodiment, the energy storage system includes a load switch and a plurality of power supply branches;

[0023] Among them, after the multiple power supply branches are connected in parallel, they are electrically connected to the energy storage converter through the load switch.

[0024] In one embodiment, the load switch includes a release, and the release is used to cut off the main circuit of the energy storage system.

[0025] In one embodiment, after the energy storage inverter controls the battery pack in the power supply branch to stop charging or discharging, if the current of the main circuit of the energy storage system is not a preset current, the load switch is disconnected to cut off the main circuit of the energy storage system.

[0026] In one embodiment, after the energy storage inverter controls the battery pack in the power supply branch to stop charging or discharging, if the current of the main circuit of the energy storage system is not a preset current and the load switch is not disconnected, the first relay in the power supply branch is disconnected.

[0027] The energy storage system provided by the present application is provided with a first fuse and a first relay in a high-voltage box, and at the same time, the first fusing current of the first fuse is not less than the first current and not greater than the second current, the first disconnecting current of the first relay is not less than the third current and not greater than the fourth current, and the fourth current is not less than the first current and less than the second current. Therefore, not only when a small fault current appears in the power supply branch, the relay can be directly used to cut off the power supply branch, but also when a large fault current appears in the power supply branch, the fuse can be used to cut off the power supply branch, thereby realizing global range fault protection for the energy storage system and improving the safety performance of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 1 A schematic block diagram of an energy storage system provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the protection range of relays and fuses in the energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" 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.

[0033] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0034] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0035] See also Figure 1 and Figure 2 , Figure 1 A schematic block diagram of an energy storage system provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the protection range of relays and fuses in the energy storage system provided in the embodiment of the present application. Figure 1 and Figure 2 As shown, an energy storage system includes at least one power supply branch, wherein the power supply branch includes:

[0036] at least one battery pack including an input terminal and an output terminal;

[0037] The high-voltage box comprises a first interface, a second interface, a third interface and a fourth interface, wherein the first interface is electrically connected to an input end, the second interface is electrically connected to an output end, and the third interface and the fourth interface are electrically connected to target devices respectively;

[0038] Wherein, the high-voltage box also includes a first fuse and a first relay, and the first fuse and the first relay are arranged between the first interface and the third interface, or the first fuse and the first relay are arranged between the second interface and the fourth interface;

[0039] The first fusing current of the first fuse is not less than the preset first current and not greater than the preset second current, the first disconnecting current of the first relay is not less than the preset third current and not greater than the preset fourth current, and the fourth current is not less than the first current and less than the second current.

[0040] In this embodiment, the first disconnecting current is a current for disconnecting the first relay, the first blowing current is a current for blowing the first fuse, the current at which the first fuse blows is set between the first current and the second current, the current at which the first relay is disconnected is set between the third current and the fourth current, and the fourth current is greater than or equal to the second current. Not only can the first relay be used to directly cut off the power supply branch when a small fault current appears in the power supply branch, but the first fuse can also be used to directly cut off the power supply branch when a large fault current appears in the power supply branch, thereby achieving global coverage of the fault current, improving the safety performance of the energy storage system, and also reducing the maintenance cost of the energy storage system.

[0041] Specifically, when a short circuit fault occurs in the power supply branch, if the fault current of the power supply branch is between the third current and the fourth current, the first relay can be controlled to disconnect to cut off the circuit of the corresponding power supply branch; if the fault current of the power supply branch is between the fourth current and the second current, the first fuse can be blown to cut off the circuit of the corresponding power supply branch; if the fault current of the power supply branch is between the first current and the fourth current and the first relay is stuck, the first fuse can be blown to cut off the circuit of the corresponding power supply branch; if the fault current of the power supply branch is between the first current and the fourth current and the first relay is not stuck, the first relay can be controlled to disconnect to cut off the circuit of the corresponding power supply branch.

[0042] It should be noted that the on and off of the relays in the energy storage system can be controlled by the battery management system in which the energy storage system is located.

[0043] In one embodiment, Figure 2 As shown, when the fault current of the power supply branch is greater than or equal to the first current and less than the fourth current, the fusing time of the first fuse is less than the disconnecting time of the first relay.

[0044] Specifically, during the normal operation of the relay, if the current in the power supply branch is too large, the relay is prone to adhesion. At the same time, if the fault current of the present application is greater than the first current, the fault current can already blow the first fuse, so the fault current at this time must be large, so the probability of the first relay being adhered is also relatively large. For this reason, the present embodiment preferably uses the first fuse to cut off the power supply branch, that is, the blowing time of the first fuse is less than the disconnection time of the first relay, so as to avoid overload and improve the safety performance of the energy storage system. In addition, if the fault current of the power supply branch is greater than the third current and less than the first current, although the first fuse will not blow, there is a fault in the power supply branch at this time. In order to avoid the energy storage system from operating when there is a fault in the power supply branch, and because the probability of the first relay being adhered between the third current and the first current is low, the first relay can be disconnected to ensure the safety of the battery pack where the power supply branch is located, thereby improving the safety performance of the energy storage system.

[0045] It can be understood that the first current in this embodiment is not less than the third current. If the first current is equal to the third current, the first fuse will be blown first. Although this can ensure the coverage of global faults, in order to reduce the number of replacement times of the first fuse, this embodiment prefers to select the first current to be greater than the third current.

[0046] In addition, when the power supply branch adopts the first relay and the first fuse for full current range protection, the critical current used by the first relay and the first fuse to cut off the power supply branch can be less than the fourth current and greater than the first current, and the critical current can be 3200A.

[0047] It should be noted that when the critical current is set, it is necessary to ensure that when the first relay reaches the disconnection condition, the probability of the first relay sticking is low, and the number of replacement times of the first fuse can be reduced as much as possible, thereby not only ensuring the coverage of global faults of the energy storage system and improving the safety performance of the energy storage system, but also reducing the maintenance cost of the energy storage system.

[0048] In one embodiment, Figure 1 and Figure 2 As shown, each battery pack includes a second fuse and at least one battery cell, and the second fuse and at least one battery cell are connected in series and are respectively connected to the input end and the output end of the battery pack;

[0049] Or, each battery pack includes at least one second fuse and at least one battery cell, and the second fuse and the battery cell are connected in series one by one and are respectively electrically connected to the input end and the output end to achieve parallel connection;

[0050] The second fusing current of the second fuse is not less than a preset fifth current and not greater than a preset sixth current, and the fifth current is less than or equal to the fourth current and greater than or equal to the first current.

[0051] In this embodiment, a second fuse is provided in the battery pack, so that when a short circuit occurs in the battery pack, the second fuse can be used to promptly cut off the circuit in which the battery pack is located to ensure the safety of the battery pack. At the same time, the present application also sets the second fusing current of the second fuse to be no less than a preset fifth current and no greater than a preset sixth current, and the fifth current is less than the fourth current and greater than the first current, so as to avoid the second fuse from blowing earlier than the first fuse. Therefore, when the fuse of the power supply branch is replaced subsequently, the number of times the second fuse is replaced is reduced, thereby reducing the number of times the battery pack is disassembled and assembled, thereby greatly improving the maintenance efficiency of the energy storage system and reducing the maintenance cost of the energy storage system.

[0052] In addition, when the fifth current is equal to the fourth current and the fifth current is equal to the first current, the first fuse and the second fuse in the same power supply branch both meet the conditions for blowing. At this time, in order to avoid increasing the number of times the battery pack is disassembled and assembled, it is necessary to set the blowing speed of the first fuse to be greater than the blowing speed of the second fuse.

[0053] Further, in one embodiment, if Figure 2 As shown, in the power supply branch, the fusing speed of the first fuse is greater than the fusing speed of the second fuse.

[0054] In this embodiment, by setting the melting speed of the first fuse to be greater than the melting speed of the second fuse, after the first fuse and the second fuse both meet the melting conditions, the first fuse can be blown preferentially, and the second fuse will not be blown at this time, thereby avoiding increasing the number of times the battery pack is disassembled and assembled. At the same time, when the second fuse is blown between the fifth current and the sixth current, the fifth current can be greater than the critical current between the first relay and the first fuse, and then when the first relay and the first fuse both fail, the second fuse can be used to cut off the power supply branch to improve the safety of the energy storage system.

[0055] In some embodiments, Figure 1 As shown, the power supply branch includes multiple battery packs, and the multiple battery packs are connected in series.

[0056] In this embodiment, multiple battery packs are arranged in each power supply branch. Each battery pack can also be connected in series with a fuse and / or a relay, which can not only increase the voltage of the power supply branch but also enhance the safety performance of the power supply branch.

[0057] In some embodiments, Figure 1As shown, the high-voltage box also includes a third fuse; wherein, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse is arranged between the second interface and the fourth interface; or the first fuse and the first relay are arranged between the second interface and the fourth interface, and the third fuse is arranged between the first interface and the third interface; the third fusing current of the third fuse is not less than the first current and not greater than the second current.

[0058] In this embodiment, fuses are provided on both the high side and the low side of the high-voltage box, thereby ensuring that no matter a short circuit fault occurs on the high side or the low side of the high-voltage box, the fuse can be used to cut off the circuit of the power supply branch, thereby ensuring the safety of the energy storage system.

[0059] In some embodiments, Figure 1 As shown, the high-voltage box also includes a second relay; wherein, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse and the second relay are arranged between the second interface and the fourth interface; the second disconnection current of the second relay is not less than the third current and not greater than the fourth current.

[0060] Specifically, the present application can also set fuses and relays on both the high side and the low side of the high-voltage box, thereby further forming a complete short-circuit protection for the power supply branch, thereby further improving the safety performance of the energy storage system.

[0061] In one embodiment, Figure 1 As shown, the target device in the energy storage system may be a power conversion system (PCS). The power conversion system (PCS) may control the charging and discharging process of the power supply branch and perform AC / DC conversion. Meanwhile, the PCS may also directly supply power to the AC load without a power grid.

[0062] In this embodiment, when the current of the power supply branch is not less than the preset seventh current and not greater than the preset eighth current, the energy storage inverter PCS controls the battery pack in the power supply branch to stop charging and / or stop discharging; wherein the eighth current is less than or equal to the fourth current.

[0063] Further, in one embodiment, if Figure 1 As shown, the energy storage system includes multiple power supply branches and load switches; wherein, after the multiple power supply branches are connected in parallel, they are electrically connected to the energy storage converter PCS through the load switch.

[0064] Specifically, one end of the load switch is electrically connected to the third interface and the fourth interface of the high-voltage box in each power supply branch, and the other end of the load switch is electrically connected to the energy storage converter PCS.

[0065] In this embodiment, a load switch is provided between the energy storage inverter PCS and the high-voltage box, so that when the relay in the high-voltage box and / or the relay in the battery pack cannot be disconnected, the load switch can be used to disconnect the main circuit of the energy storage system, thereby further ensuring the safety performance of the energy storage system.

[0066] In one embodiment, when the current of the power supply branch is not less than a preset seventh current and not greater than a preset eighth current, the energy storage inverter PCS controls the battery pack in the power supply branch to stop charging and / or stop discharging; wherein the eighth current is less than or equal to the fourth current.

[0067] In this embodiment, when the current of the power supply branch is not less than the preset seventh current and not greater than the preset eighth current, a short circuit fault occurs in the power supply branch, and the current of the power supply branch is a fault current. In order to improve the life of the first relay in the high-voltage box and avoid the first relay from being unable to disconnect due to adhesion due to excessive current, the present application preferably uses an energy storage inverter PCS to control the battery pack in the power supply branch to stop charging or / and stop discharging. At the same time, the seventh current can be 210A, and the eighth current can be used as the critical current between the first relay and the first fuse, that is, it can be 3200A. Therefore, the eighth current needs to be less than or equal to the fourth current, so that the first relay and the first fuse can cover the global range faults of the energy storage system.

[0068] In addition, when the current of the power supply branch is greater than the eighth current, the first fuse in the high-voltage box of the power supply branch needs to be blown, and the first relay in the high-voltage box of other power supply branches needs to be disconnected to put the energy storage system in standby mode.

[0069] In one embodiment, when the energy storage inverter controls the battery pack in the power supply branch to stop charging and / or discharging, if the current of the main circuit of the energy storage system is not a preset current, the load switch is disconnected to cut off the main circuit of the energy storage system.

[0070] In this embodiment, when the battery pack in the power supply branch controlled by the energy storage converter PCS stops charging or discharging, the main circuit of the energy storage system is usually in a cut-off state. In order to avoid the situation where the main circuit of the energy storage system is not cut off, after the battery pack in the power supply branch controlled by the energy storage converter PCS stops charging or discharging, the present application can determine whether the main circuit of the energy storage system is in a cut-off state by detecting whether the current of the main circuit of the energy storage system is a preset current. If the current of the main circuit of the energy storage system is detected to be the preset current, then it can be determined that the main circuit of the energy storage system is in a cut-off state; if the current of the main circuit of the energy storage system is not the preset current, then it can be determined that the main circuit of the energy storage system is in an uncut-off state, and then a load switch is required to cut off the main circuit of the energy storage system. At the same time, in order to avoid directly cutting off the load switch before the main circuit is discharged, the present application can also delay the preset time to cut off the load switch. Among them, the preset current can be zero current, and the preset time can be 3s.

[0071] In one embodiment, when the energy storage converter PCS controls the battery pack in the power supply branch to stop charging and / or discharging, if the current of the main circuit of the energy storage system is not a preset current and the load switch is not disconnected, the first relay in the power supply branch is disconnected.

[0072] Specifically, in order to avoid the situation where the current in the main circuit of the energy storage system is not the preset current and the load switch is not disconnected after the battery pack in the power supply branch is controlled by the energy storage inverter PCS to stop charging and / or discharging, the present application can also force the first relay in the power supply branch to perform a forced cut to ensure the safety of the battery pack in the energy storage system.

[0073] It should be noted that when controlling the first relay in the power supply system to be disconnected, at least the first relay in the power supply branch where the fault current occurs needs to be controlled to be disconnected. That is to say, after the energy storage converter PCS controls the battery pack in the power supply branch to stop charging or / and stop discharging, if the current of the main circuit of the energy storage system is not the preset current and the load switch is not disconnected, the first relays in all power supply branches in the energy storage system can be disconnected, or the first relays in some power supply branches in the energy storage system can be disconnected, wherein some power supply branches include the power supply branch where the fault occurs.

[0074] In some embodiments, Figure 1 As shown, the load switch includes a release; wherein the release is used to cut off the main circuit of the energy storage system.

[0075] Specifically, the present application can cut off the main circuit of the energy storage system by setting a release in the load switch. Among them, the release can be used when there is leakage in the line or electric shock to a person. The vector sum of the current through the zero-sequence current transformer is not equal to zero, and the two sides of the transformer secondary coil generate voltage, which is amplified by the integrated circuit. When the set value is reached, the leakage release is used to quickly cut off, thereby playing a role in electric shock and leakage protection.

[0076] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An energy storage system, characterized in that: The invention comprises at least one power supply branch, wherein the power supply branch comprises: at least one battery pack including an input terminal and an output terminal; A high voltage box, comprising a first interface, a second interface, a third interface and a fourth interface, wherein the first interface is electrically connected to the input end, the second interface is electrically connected to the output end, and the third interface and the fourth interface are electrically connected to the target device respectively; Wherein, the high-voltage box further includes a first fuse and a first relay, the first fuse and the first relay are arranged between the first interface and the third interface, or the first fuse and the first relay are arranged between the second interface and the fourth interface; The first fusing current of the first fuse is not less than a preset first current and not greater than a preset second current, the first disconnecting current of the first relay is not less than a preset third current and not greater than a preset fourth current, and the fourth current is not less than the first current and less than the second current.

2. The energy storage system according to claim 1, characterized in that: When the fault current of the power supply branch is greater than or equal to the first current and less than the fourth current, the fusing time of the first fuse is less than the disconnecting time of the first relay.

3. The energy storage system according to claim 1, characterized in that: Each of the battery packs includes a second fuse and at least one battery cell, and the second fuse and at least one battery cell are connected in series and are respectively connected to the input end and the output end; Or, each of the battery packs includes at least one second fuse and at least one battery cell, and the second fuse and the battery cell are connected in series one by one and are respectively electrically connected to the input end and the output end to achieve parallel connection; The second fusing current of the second fuse is not less than a preset fifth current and not greater than a preset sixth current, and the fifth current is less than or equal to the fourth current and greater than or equal to the first current.

4. The energy storage system according to claim 3, characterized in that: In the power supply branch, a fusing speed of the first fuse is greater than a fusing speed of the second fuse.

5. The energy storage system according to claim 1, characterized in that: The high voltage box also includes a third fuse; Wherein, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse is arranged between the second interface and the fourth interface; or the first fuse and the first relay are arranged between the second interface and the fourth interface, and the third fuse is arranged between the first interface and the third interface; A third fusing current of the third fuse is not less than the first current and not greater than the second current.

6. The energy storage system according to claim 5, characterized in that: The high voltage box also includes a second relay; Among them, the first fuse and the first relay are arranged between the first interface and the third interface, and the third fuse and the second relay are arranged between the second interface and the fourth interface; the second disconnection current of the second relay is not less than the third current and not greater than the fourth current.

7. The energy storage system according to any one of claims 1 to 6, characterized in that: The power supply branch includes a plurality of battery packs, and the plurality of battery packs are connected in series.

8. The energy storage system according to any one of claims 1 to 6, characterized in that: The target device is an energy storage converter; When the current of the power supply branch is not less than a preset seventh current and not greater than a preset eighth current, the energy storage inverter controls the battery pack in the power supply branch to stop charging and / or discharging; wherein the eighth current is less than or equal to the fourth current.

9. The energy storage system according to claim 8, characterized in that: The energy storage system comprises a load switch and a plurality of power supply branches; Among them, after the multiple power supply branches are connected in parallel, they are electrically connected to the energy storage converter through the load switch.

10. The energy storage system according to claim 9, characterized in that: The load switch comprises a release, and the release is used to cut off the main circuit of the energy storage system.

11. The energy storage system according to claim 9, characterized in that: After the energy storage inverter controls the battery pack in the power supply branch to stop charging and / or discharging, if the current of the main circuit of the energy storage system is not the preset current, the load switch is disconnected to cut off the main circuit of the energy storage system.

12. The energy storage system according to claim 11, characterized in that: After the energy storage inverter controls the battery pack in the power supply branch to stop charging and / or discharging, if the current of the main circuit of the energy storage system is not a preset current and the load switch is not disconnected, the first relay in the power supply branch is disconnected.

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