Protection circuit of energy storage system, battery pack and energy storage system

Abstract

The present disclosure provides a protection circuit, a battery pack and an energy storage system for an energy storage system. The energy storage system includes a plurality of battery clusters, each of which includes a plurality of battery packs, each of which includes a plurality of battery cells, and the protection circuit includes: an intra-cluster protection circuit, including a first fuse installed at the positive and / or negative pole of at least one of the plurality of battery packs; and an extra-cluster protection circuit, including a second fuse installed outside the battery cluster and connected to the positive and / or negative pole of the battery cluster, the pre-arcing I²t of the first fuse being greater than the fusing I²t of the second fuse. The internal and external fuses of the battery pack of the present disclosure cooperate with each other, and the fuses in the pack cooperate with the high-voltage box fuses and circuit breakers to achieve multiple protections, which can make the protection of the energy storage system more comprehensive, effectively protect against short circuits in the battery cluster, and greatly reduce the possibility of relay damage.

Description

Technical Field

[0001] The present application relates to the field of energy storage systems, and more specifically, to a protection circuit, a battery pack and an energy storage system for energy storage systems. Background Art

[0002] Current energy storage systems typically use a single circuit breaker to replace components such as disconnectors, fuses, and contactors in traditional current protection circuits.

[0003] However, this design does not fully consider the coordination between the fuse inside the battery pack and the fuse outside the pack, and does not provide effective protection against short circuits in the battery cluster. Currently, there is no research on setting fuses inside the battery pack, and when a short circuit occurs in the cluster, it cannot effectively protect the safety and stability of the battery cells.

[0004] Furthermore, when a short circuit occurs in the battery cluster, if this coordination is not perfect, protection may not be achieved in a timely and accurate manner, causing a series of safety hazards and failures.

[0005] As one of the key components in the energy storage system, the relay also needs fuses and circuit breakers to provide effective protection when abnormal fluctuations occur in current, voltage and other parameters to ensure the normal operation of the relay and the stability of the entire system. The current high-voltage box fuse (i.e., external fuse) cannot effectively protect the relay. When encountering a fault current, the relay is prone to burn out. Utility Model Content

[0006] One of the objectives of the present disclosure is to provide a protection circuit capable of protecting a battery cluster when a short circuit occurs in the battery cluster.

[0007] One of the purposes of the present disclosure is to provide a coordinated protection circuit inside and outside a battery cluster, which can more comprehensively protect the safety of an energy storage system.

[0008] According to a first aspect of the present disclosure, there is provided a protection circuit for an energy storage system, the energy storage system comprising a plurality of battery clusters, each battery cluster comprising a plurality of battery packs, each battery pack comprising a plurality of battery cells, the protection circuit comprising: an intra-cluster protection circuit comprising a first fuse installed at a positive electrode and / or a negative electrode of at least one battery pack among the plurality of battery packs; and an extra-cluster protection circuit comprising a second fuse installed outside the battery cluster and connected to the positive electrode and / or the negative electrode of the battery cluster, wherein the pre-arcing I²t of the first fuse is greater than the fusing I²t of the second fuse.

[0009] According to an embodiment of the present disclosure, the intra-cluster protection circuit may include a plurality of first fuses, the plurality of first fuses may be arranged one-to-one at the negative poles of a plurality of battery packs and the second fuses may be connected to the positive pole of the battery cluster, or the plurality of first fuses may be arranged one-to-one at the positive poles of a plurality of battery packs and the second fuses may be connected to the negative pole of the battery cluster.

[0010] According to an embodiment of the present disclosure, a plurality of first fuses may be connected in series to one another within the battery cluster.

[0011] According to an embodiment of the present disclosure, the energy storage system may further include a power conversion circuit, and the battery pack is connected to the power conversion circuit via an external cluster protection circuit.

[0012] According to an embodiment of the present disclosure, the off-cluster protection circuit may further include: a circuit breaker, arranged on the positive branch and / or negative branch of the protection circuit; a current detector and a relay, connected in series with each other between the circuit breaker and the negative electrode of the battery cluster, or connected in series with each other between the circuit breaker and the positive electrode of the battery cluster.

[0013] According to an embodiment of the present disclosure, the out-of-cluster protection circuit may further include a contactor connected between the circuit breaker and the second fuse.

[0014] According to an embodiment of the present disclosure, the withstand time of the relay may be higher than the breaking time of the second fuse.

[0015] According to an embodiment of the present disclosure, a plurality of battery clusters may be connected to each other in parallel, a plurality of battery packs may be connected to each other in series, and a plurality of battery cells may be connected to each other in series.

[0016] According to a second aspect of the present disclosure, a battery pack of an energy storage system is provided. The battery pack includes a battery cluster and the above protection circuit. The battery cluster is connected to a power conversion system through the protection circuit.

[0017] According to a third aspect of the present disclosure, there is provided an energy storage system, which includes a battery cluster, the above-mentioned protection circuit, and a power conversion system, wherein the battery cluster is connected to the power conversion system via the protection circuit.

[0018] The protection circuit according to the embodiment of the present disclosure can avoid batch replacement of fuses in battery packs.

[0019] The protection circuit according to the embodiment of the present disclosure can reduce the probability of damage to the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram showing a protection circuit of an energy storage system according to an embodiment of the present disclosure;

[0021] Figure 2 is a schematic diagram showing a short-circuit point of an energy storage system according to an embodiment of the present disclosure;

[0022] Figure 3 is a block diagram illustrating operation or device status fault protection according to an embodiment of the present disclosure;

[0023] Figure 4 is a diagram showing a pre-arcing characteristic curve of a first fuse, a pre-arcing characteristic curve of a second fuse, a relay current withstand curve, a circuit breaker tripping curve, and a circuit breaker shunt curve according to the present disclosure;

[0024] Figure 5 2 is a time-current characteristic curve showing a first fuse and a second fuse according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The following detailed description is provided to help gain a comprehensive understanding of the methods, devices and / or systems described herein. However, the order of operations described herein is only an example and is not limited to those orders set forth herein, but may be equivalently replaced or changed except for operations that must occur or be performed in a specific order. In addition, for greater clarity and simplicity, the description of content known in the art will be omitted or simplified.

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which the present disclosure belongs after understanding the present disclosure. Unless explicitly defined as such herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0027] Unless otherwise specified, the same reference numerals generally refer to the same elements (e.g., components, steps, and methods). Reference numerals described in previous embodiments may be omitted if they appear again in later embodiments. In addition, the technical features described in different or the same embodiments may be combined in any manner, as long as the combined embodiments or technical solutions are complete and can solve the technical problems of the present application or achieve the technical effects described or not described in the present disclosure but can be determined based on the above complete technical solutions.

[0028] An energy storage system usually includes multiple battery clusters, a battery management system (BMS), a power conversion system (PCS), a control system, a protection circuit, and so on.

[0029] Multiple battery clusters and protection circuits can form a battery pack, each battery cluster includes multiple battery packs, each battery pack includes multiple battery cells, and the battery cells are generally connected in series to store electrical energy. Common battery packs may include different types of battery packs such as lithium-ion batteries and lead-acid batteries.

[0030] The battery management system (BMS) is generally used to monitor the status of the battery pack, such as voltage, current, temperature, etc., to ensure the safe and efficient operation of the battery and control the normal operation of the battery.

[0031] The power conversion system (PCS) realizes the conversion of electric energy between the battery and the power grid or other loads. The power conversion system may include functional circuits such as rectification and inversion, which can convert DC power into AC power or AC power into DC power according to demand.

[0032] The control system can coordinate the entire energy storage system and determine the operating mode and action of the energy storage system based on various input information and preset strategies.

[0033] The protection circuit may include a protection circuit such as a fuse, which is used to protect the safety of the energy storage system under abnormal conditions such as overcurrent and overvoltage.

[0034] The above division of functional modules is only an example. As an example, at least one of the battery management system, the control system, etc. may be a part of the protection circuit of the energy storage system.

[0035] According to an embodiment of the present disclosure, a fuse (ie, a first fuse) is added to a battery pack to prevent a short circuit within a cluster. The intra-cluster protection circuit according to an embodiment of the present disclosure can protect each battery cluster.

[0036] In addition, according to the embodiment of the present disclosure, the cluster protection circuit cooperates with the cluster protection circuit, and when a short circuit occurs in the battery cluster, hierarchical protection can be achieved to better protect the safety and stability of the system. Specifically, the internal and external fuses and circuit breakers of the battery pack of the present disclosure cooperate with each other, and the fuses in the pack cooperate with the high-voltage box fuses and circuit breakers to achieve multiple protections, which can make the protection of the energy storage system more comprehensive, effectively prevent the short circuit in the battery cluster, and greatly reduce the possibility of relay damage.

[0037] Specific embodiments of the present disclosure will be described below in conjunction with the accompanying drawings.

[0038] Figure 1 is a schematic diagram showing a protection circuit of an energy storage system according to an embodiment of the present disclosure; Figure 2 is a schematic diagram showing a short-circuit point of an energy storage system according to an embodiment of the present disclosure; Figure 3 is a block diagram illustrating operation or device status fault protection according to an embodiment of the present disclosure; Figure 4 is a diagram showing a pre-arcing characteristic curve of a first fuse, a pre-arcing characteristic curve of a second fuse, a relay current withstand curve, a circuit breaker tripping curve, and a circuit breaker shunt curve according to the present disclosure; Figure 52 is a time-current characteristic curve showing a first fuse and a second fuse according to an embodiment of the present disclosure.

[0039] Reference Figure 1 and Figure 2 According to an embodiment of the present disclosure, the energy storage system may include a plurality of battery clusters 20 , each battery cluster 20 may include a plurality of battery packs 21 , the plurality of battery packs 21 may be connected in series to each other, and each battery pack may include a plurality of battery cells.

[0040] Although not shown, multiple battery clusters may be connected to the PCS in parallel, and the cells in each battery pack may be connected in series, but this is only an example, and the cells of the battery pack may also be connected in parallel. The number of cells in each battery pack may be determined according to the capacity of the energy storage system.

[0041] Each battery cluster according to an embodiment of the present disclosure may include at least two battery packs. Figure 1 and Figure 2 The number of battery packs in each battery cluster is eight, but this is merely exemplary, and the number of battery packs may also be 16, 32, 64, and so on.

[0042] The protection circuit according to the embodiment of the present disclosure may include an intra-cluster protection circuit, which may include a fuse installed at the positive or negative electrode of the battery pack (i.e., an intra-pack fuse or an intra-pack fuse). The fuse can be used for overload protection (when the current in the circuit exceeds the rated current of the fuse to a certain extent and lasts for a period of time, the fuse will melt, thereby cutting off the circuit to prevent battery damage or more serious faults caused by overload), short-circuit protection (when a short-circuit fault occurs in the circuit, a huge current will be generated instantly, and the fuse can quickly melt to disconnect the circuit to protect the line and battery from damage by the short-circuit current), isolation fault (effectively isolate the faulty part from the normally operating circuit to avoid the expansion of the fault range and ensure the safe and stable operation of the entire system), etc. The rated current, rated voltage, breaking capacity, etc. of the fuse can be determined according to the specification parameters of other components of the protection circuit.

[0043] For details, please refer to Figure 1 The intra-cluster protection circuit may include a first fuse 22 installed at a positive electrode and / or a negative electrode of at least one battery pack among the plurality of battery packs 21 .

[0044] As an example, the protection circuit within the cluster may include multiple first fuses 22, and the first fuses 22 may be set at the positive and negative electrodes of each battery pack 21. When the first fuses 22 are set at both the positive and negative electrodes of the battery pack, the safety and reliability of the battery cluster can be further improved. The first fuse 22 at the positive or negative electrode can prevent abnormal conditions such as overcurrent, short circuit, etc. from occurring when the current flows out of the positive electrode of the battery pack. This dual fuse setting can improve the safety of the circuit within the cluster.

[0045] In order to reduce costs, the plurality of first fuses 22 may be disposed one by one at the negative electrodes or positive electrodes of the plurality of battery packs 21, that is, each battery pack 21 may include only one fuse. Each battery cluster 20 may include a plurality of first fuses 22, and the plurality of first fuses 22 may be connected in series with each other in the battery cluster 20.

[0046] The number of the first fuses 22 in each battery cluster may correspond to the number of the battery packs 21. In other words, the number of the first fuses 22 may also be eight.

[0047] Reference Figure 1 and Figure 2 According to an embodiment of the present disclosure, the protection circuit of the energy storage system may further include an external cluster protection circuit 10. The external cluster protection circuit 10 may be located outside the battery cluster 20, specifically, may be located inside the high-voltage box, and may include a second fuse 13 installed outside the battery cluster and connected to the positive and / or negative poles of the battery cluster. The second fuse 13 may be connected to the positive and / or negative poles of the battery cluster 20.

[0048] As an example, in the in-cluster protection circuit, the first fuse 22 can be set at the negative electrode of the battery pack 21, and in the out-cluster protection circuit 10, the second fuse 13 can be set on the positive branch, for example, the second fuse 13 can be connected to the positive bus port B+.

[0049] Specifically, when multiple first fuses 22 are arranged one-to-one at the negative poles of multiple battery packs, the second fuse 13 can be connected to the positive pole of the battery cluster 20; when multiple first fuses 22 are arranged one-to-one at the positive poles of multiple battery packs 21, the second fuse 13 can be connected to the negative pole of the battery cluster.

[0050] The out-of-cluster protection circuit 10 according to the embodiment of the present disclosure may include one second fuse 13 , but the number of the second fuses 13 is not specifically limited, and one or more second fuses 13 may be respectively provided in the positive and negative branches of the out-of-cluster protection circuit 10 .

[0051] Reference Figure 1 and Figure 2The positive electrode of the battery cluster 20 can be connected to the positive bus port B+ of the high voltage box, and the negative electrode of the battery cluster can be connected to the negative bus port B- of the high voltage box. Although not shown, the positive port P+ and the negative port P- of the high voltage box can be connected to the positive port and the negative port of the PCS respectively.

[0052] In the cluster protection circuit, the first fuse 22 can be set at the positive electrode of the battery pack 21, and in the cluster protection circuit 10, the second fuse 13 can be set on the negative electrode branch. Figure 1 and Figure 2 The difference is that the first fuse 22 can be set at the positive electrode of the battery pack 21, and the second fuse 13 can be connected to the negative bus port B-. The matching arrangement of the positive and negative electrodes of the first fuse 22 and the second fuse 13 can improve the protection capability of the energy storage system and reduce the protection cost of the energy storage system.

[0053] Reference Figure 4 and Figure 5 , the pre-arcing I²t of the first fuse 22 (ie, the pack fuse or the fuse inside the pack) may be greater than the fusing I²t of the second fuse 13 (ie, the fuse inside the high-voltage box or the high-voltage box fuse).

[0054] As an example, the selection parameters of the first fuse (ie, the fuse in the pack) may be as follows: DC 1500V / 500A, breaking capacity of 150kA, and pre-arcing I²t of 100930 ampere square seconds.

[0055] As an example, the selection parameters of the second fuse (ie, the fuse in the high-voltage box) may be as follows: DC 1500V / 315A, breaking capacity 250kA, and fuse I²t 69800 ampere square seconds. The selection of the first fuse and the second fuse is not specifically limited.

[0056] The external cluster protection circuit 10 may further include a circuit breaker 11 disposed on the positive and negative branches of the protection circuit and a current detector 15 connected between the circuit breaker 11 and the negative electrode of the battery cluster or between the circuit breaker 11 and the positive electrode of the battery cluster.

[0057] The circuit breaker 11 may be a DC molded case circuit breaker, which may have fast closing and fast disconnecting functions, can quickly respond to faults and cut off circuits, and adopts the parallel conductor principle, which is conducive to fast disconnection at high currents. At the same time, it is equipped with components made of high arc-resistant materials, which helps to quickly extinguish the arc.

[0058] The current detector 15 may be a current transformer. The position of the current detector is not particularly limited.

[0059] The second fuse of the out-of-cluster protection circuit 10 may be installed outside the battery cluster 20 and connected to the positive electrode and / or the negative electrode of the battery cluster 20 .

[0060] The cluster protection circuit 10 may further include a relay 14, which can be activated in time to cut off the circuit to protect the safety of the equipment and system when an abnormal situation occurs in the circuit, such as overcurrent, overvoltage, etc. After the relay receives the action instruction, the contact of the relay will quickly act according to the instruction, switching from the original state to the tripping state, thereby disconnecting the circuit connected to the relay.

[0061] As an example, the current detector 15 and the relay 14 may be connected in series with each other between the circuit breaker 11 and the negative electrode of the battery cluster 20, or connected in series with each other between the circuit breaker 11 and the positive electrode of the battery cluster 20. The arrangement positions of the current detector 15 and the relay 14 are not particularly limited.

[0062] Reference Figure 4 The withstand time of the relay 14 may be higher than the breaking time of the second fuse 13, that is, when an abnormal situation requiring protection (eg, a short circuit) occurs, the relay 14 can continue to withstand this abnormal state for a longer period of time before the second fuse 13 blows and disconnects the circuit.

[0063] When a fault such as a short circuit occurs in the energy storage system, the relay's withstand current and withstand time can be higher than the cut-off current and withstand time of other devices, and the relay will not burn or explode. This can reduce the probability of relay damage.

[0064] As an example, the cluster protection circuit 10 may further include a contactor 12, which may be connected to the negative branch of the cluster protection circuit 10, for example, the contactor 12 may be connected between the circuit breaker 11 and the second fuse 13. The contactor 12 may also be provided on the positive branch of the cluster protection circuit 10.

[0065] The energy storage system according to the embodiment of the present disclosure may further include a power conversion circuit (or referred to as a power conversion system), and the battery pack 21 may be connected to the power conversion system via the off-cluster protection circuit 10. The power conversion system may be part of an energy storage converter. As an example, the battery cluster and the protection circuit may constitute a battery pack of the energy storage system, and the battery cluster may be connected to the power conversion system via the protection circuit.

[0066] The power conversion system may be part of the energy storage system, that is, the energy storage system according to the embodiment of the present disclosure may include the power conversion system in addition to the protection circuit and the battery cluster, and the battery cluster is connected to the power conversion system through the protection circuit.

[0067] The protection circuit of the energy storage system according to the embodiment of the present disclosure may further include a battery management system (BMS), although not shown, the current detector 15 may be connected to the BMS. The BMS may be used to control the on and off of the circuit breaker 11 according to the current detected by the current detector.

[0068] The battery management system (BMS) can decide whether to control the circuit breaker action based on the status of the battery cluster and related parameters such as voltage, current, temperature, etc.

[0069] For example, when the battery cluster is detected to have abnormal conditions such as overvoltage, undervoltage, overcurrent, overheating, etc., the battery management system can send a signal to the circuit breaker to trip it, so as to protect the battery cluster and effectively control the circuit. The control of the circuit breaker by the battery management system can better ensure the safe and stable operation of the energy storage system.

[0070] According to an embodiment of the present disclosure, a battery management system may include an insulation detection module and a control module. The insulation detection module may be configured to detect a short circuit to ground of a battery cluster, and the control module may be configured to: in response to detecting a single-point short circuit in the battery cluster or a short circuit in only one of the positive and negative branches, when the short-circuit current is small, control the circuit breaker to trip.

[0071] When the energy storage system encounters abnormalities such as overcurrent, overvoltage, insulation withstand voltage, etc., the active and passive components can be combined together to participate in the circuit of the energy storage system.

[0072] The battery management system can control the circuit breaker to close in response to the current detected by the current detector being in the normal current range; and can control the circuit breaker to trip in response to the current detected by the current detector being in the overcurrent range, and the lower limit value of the overcurrent range can be greater than or equal to the upper limit value of the normal current range.

[0073] As an example, the normal current range may be [0, 168) (unit: A), that is, when the current 0≤I<168, the current is normal current. When the current is in the normal range, fuses, circuit breakers, relays, etc. may not operate, and the energy storage system can work reliably for a long time.

[0074] The overcurrent range may be [168, 1680] (unit: A), that is, when the current 168≤I≤1680 (unit: A), the current is an overcurrent or an overload current, but this is only an example, and the normal current range and the overcurrent range may vary according to actual conditions.

[0075] Reference Figure 3 In the case of overload (the current detected by the current detector is in the overcurrent range), the battery management system can control the circuit breaker shunt tripping.

[0076] Reference Figure 4The passive tripping action time of the circuit breaker in the first short-circuit current range may be less than the fusing action time of the second fuse (ie, the high-voltage box fuse) in the first short-circuit current range, and the first short-circuit current range may be (1680, 3500) (unit: A).

[0077] Reference Figure 4 , the melting action time of the second fuse in the second short-circuit current range may be less than the passive tripping action time of the circuit breaker in the second short-circuit current range, and the second short-circuit current range may be [3500, 250000] (in A), that is, 3500≤I≤250000. The upper limit value of the first short-circuit current range may be less than or equal to the lower limit value of the second short-circuit current range.

[0078] The fusing current of the first fuse (i.e., the fuse in the pack) and the second fuse (i.e., the high-voltage box fuse) may be greater than the upper limit of the first short-circuit current range. The fusing current of the first fuse and the second fuse may be less than or equal to the lower limit of the second short-circuit current range, and the upper limit of the first short-circuit current range may be less than or equal to the lower limit of the second short-circuit current range. As an example, the pre-arc I²t of the second fuse may be less than the pre-arc I²t of the first fuse.

[0079] The circuit breaker and the relay may respond actively and / or passively. For example, in response to the short-circuit current of the battery cluster being in the first short-circuit current range, the circuit breaker (ie, the high-voltage box circuit breaker) is passively tripped and disconnected before the second fuse.

[0080] In response to the short-circuit current of the battery pack being in the second short-circuit current range, the second fuse may be disconnected before the circuit breaker, and the upper limit of the first short-circuit current range is less than or equal to the lower limit of the second short-circuit current range. As an example, when the short-circuit current outside the cluster is large (in the second short-circuit current range), the second fuse in the protection circuit outside the cluster is disconnected first. Thus, batch replacement of fuses in the pack can be avoided.

[0081] In addition, when a short circuit occurs outside the cluster, the protection circuit can protect the relay to avoid replacing the fuse and relay together in the high-voltage box.

[0082] Specifically, in response to a short circuit occurring within the battery cluster and the short circuit current of the battery cluster being within a first short circuit current range, both the first fuse and the second fuse may not be blown. In response to a short circuit occurring within the battery cluster and the short circuit current of the battery cluster being within a second short circuit current range, both the first fuse and the second fuse may be blown. Similarly, the upper limit value of the first short circuit current range may be less than or equal to the lower limit value of the second short circuit current range.

[0083] As an example, in response to an external short circuit of the battery cluster and the short circuit current of the battery cluster being in a first short circuit current range, the first fuse and the second fuse may not be blown. As an example, in response to an external short circuit of the battery cluster and the short circuit current of the battery cluster being in a second short circuit current range, the second fuse may be blown and the first fuse may operate normally.

[0084] Specifically, refer to Figure 2 and Figure 3 When a short circuit occurs at the short-circuit point B1 or the short-circuit point B2 (ie, the positive and negative poles are short-circuited within the cluster), both the first fuse and the second fuse are activated, thereby cutting off the energy exchange between multiple clusters.

[0085] Reference Figure 3 If a short circuit occurs at the short-circuit point B1 or the short-circuit point B2, and the short-circuit current is in the first short-circuit current range (ie, 1680<I<3500), the circuit breaker 11 (ie, the high-voltage box circuit breaker) is passively tripped, thereby achieving fault isolation.

[0086] If a short circuit occurs between short-circuit point B1 and short-circuit point B2, and the short-circuit current is in the second short-circuit current range (i.e., 3500≤I≤250000), the second fuse (i.e., the fuse in the high-voltage box) is blown, and the first fuse (i.e., the fuse in the pack) is blown. At this time, the BMS can send a trip command to the circuit breaker to control the circuit breaker shunt tripping.

[0087] Reference Figure 2 and Figure 3 , if a short circuit occurs at the short-circuit point A1 (i.e., short circuit outside the cluster), the fuse in the high-voltage box protects, and the fuse in the pack does not operate, that is, the melting I²t of the second fuse can be smaller than the pre-arcing I²t of the first fuse.

[0088] Specifically, refer to Figure 3 If a short circuit occurs at the short-circuit point A1 and the short-circuit current is in the first short-circuit current range (ie, 1680<I<3500), the circuit breaker 11 (ie, the high-voltage box circuit breaker) is passively tripped, thereby achieving fault isolation.

[0089] If a short circuit occurs at the short-circuit point A1 and the short-circuit current is in the second short-circuit current range (ie, 3500≤I≤250000), the second fuse (ie, the fuse in the high-voltage box) is blown and the first fuse (ie, the fuse in the pack) is normal.

[0090] Although not shown, as described above, the battery management system (BMS) may include an insulation detection module and a control module. The insulation detection module may be configured to detect a short circuit to ground (a single-point short circuit to ground or a multi-point short circuit to ground) of a battery cluster. The control module may be configured to: in response to detecting a single-point short circuit in the battery cluster or a short circuit in only one of the positive and negative branches, control the circuit breaker to trip.

[0091] Reference Figure 2 and Figure 3 If the insulation detection module detects that any point among the short-circuit points C1 to C4 is short-circuited (short-circuited to ground), or the short-circuit points C1 and C4 are short-circuited at the same time, or the short-circuit points C2 and C3 are short-circuited at the same time, since the short-circuit current is relatively small and only passes through one pole of the circuit breaker, the single-pole breaking capacity of the circuit breaker is needed to protect against this fault.

[0092] Reference Figure 2 and Figure 3 If the positive and negative electrodes are short-circuited to the ground at the same time (short-circuit point C2 and short-circuit point C4 are short-circuited at the same time, or short-circuit point C1 and short-circuit point C3 are short-circuited at the same time), the first fuse (i.e., the fuse in the pack) may be blown, thereby eliminating the fault and protecting the battery pack in the battery cluster.

[0093] This allows for hierarchical protection, making the short-circuit protection on the DC side of the battery portion of the energy storage system more comprehensive and able to effectively respond to different short circuits.

[0094] The protection circuit according to the embodiment of the present disclosure can protect the battery cluster when a short circuit occurs in the battery cluster.

[0095] The protection circuit according to the embodiment of the present disclosure can realize the coordinated protection circuit inside and outside the battery cluster, and can more comprehensively protect the safety of the energy storage system.

[0096] The protection circuit according to the embodiment of the present disclosure can avoid batch replacement of fuses in battery packs.

[0097] The protection circuit according to the embodiment of the present disclosure can reduce the probability of damage to the relay.

[0098] The specific implementation methods of the present disclosure are described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments can be combined, modified and improved without departing from the principle and spirit of the present invention whose scope is defined by the claims and their equivalents. These combinations, modifications and improvements should also be within the scope of protection of the present invention.

Claims

1. A protection circuit for an energy storage system, characterized in that: The energy storage system includes a plurality of battery clusters, each battery cluster includes a plurality of battery packs, each battery pack includes a plurality of battery cells, and the protection circuit includes: an intra-cluster protection circuit, comprising a first fuse mounted at a positive electrode and / or a negative electrode of at least one battery pack among the plurality of battery packs; and an external cluster protection circuit, comprising a second fuse installed outside the battery cluster and connected to the positive electrode and / or the negative electrode of the battery cluster, Among them, the pre-arcing I2t of the first fuse is greater than the fusing I2t of the second fuse.

2. The protection circuit of the energy storage system according to claim 1, characterized in that: The intra-cluster protection circuit includes a plurality of first fuses, The plurality of first fuses are arranged one-to-one at the negative electrodes of the plurality of battery packs and the second fuse is connected to the positive electrode of the battery cluster, or the plurality of first fuses are arranged one-to-one at the positive electrodes of the plurality of battery packs and the second fuse is connected to the negative electrode of the battery cluster.

3. The protection circuit of the energy storage system according to claim 2, characterized in that: The plurality of first fuses are connected in series with one another within the battery cluster.

4. The protection circuit of the energy storage system according to claim 1, characterized in that: The energy storage system further includes a power conversion circuit, and the battery pack is connected to the power conversion circuit via the external cluster protection circuit.

5. The protection circuit of the energy storage system according to claim 4, characterized in that: The out-of-cluster protection circuit also includes: A circuit breaker is arranged on the positive branch and / or the negative branch of the protection circuit; The current detector and the relay are connected in series between the circuit breaker and the negative electrode of the battery cluster, or are connected in series between the circuit breaker and the positive electrode of the battery cluster.

6. The protection circuit of the energy storage system according to claim 5, characterized in that: The out-of-cluster protection circuit further includes a contactor connected between the circuit breaker and the second fuse.

7. The protection circuit of the energy storage system according to claim 5, characterized in that: The withstand time of the relay is higher than the breaking time of the second fuse.

8. The protection circuit of the energy storage system according to claim 1, characterized in that: The plurality of battery clusters are connected in parallel to one another, the plurality of battery packs are connected in series to one another, and the plurality of battery cells are connected in series to one another.

9. A battery pack of an energy storage system, characterized in that: The invention comprises a battery cluster and a protection circuit according to any one of claims 1 to 8, wherein the battery cluster is connected to a power conversion system via the protection circuit.

10. An energy storage system, characterized in that: The invention comprises a battery cluster, a protection circuit according to any one of claims 1 to 8, and a power conversion system, wherein the battery cluster is connected to the power conversion system via the protection circuit.

Images