A control method for a high-voltage box and a high-voltage circuit used in an energy storage system

Abstract

The present invention provides a high-voltage box and a control method for a high-voltage circuit applied to an energy storage system. The high-voltage box is connected between a battery cluster and a load, and includes: a current sensor, a fuse, a total voltage collector, a switch branch, and an arc-proof element; the fuse is used to cut off the current when the cluster end current of the battery cluster exceeds the fuse value of the fuse, and the total voltage collector is used to collect the total voltage of the battery cluster and the total voltage of the load; the charging resistance branch includes a first pre-charging resistance branch and a second pre-charging resistance branch, the first pre-charging resistance branch is connected between the fuse and the positive electrode of the load, and the second pre-charging resistance branch is connected between the negative electrode of the battery cluster and the negative electrode of the load; the arc-proof element is arranged on the main branch or the pre-charging resistance branch, and the arc-proof element is used to remove the circuit arc caused when the main branch is disconnected. By using a high-voltage box including an arc-proof element, the voltage and current of the switch node of the high-voltage box are reduced, and the circuit arc is effectively prevented.

Description

Technical Field

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

[0002] A high-voltage box is a device used for high-voltage power transmission, distribution and control. It usually has built-in sensors and monitoring devices, which can monitor the voltage, current, temperature and other parameters of the energy storage system in real time and transmit this information to the control system. At the same time, the high-voltage box also receives instructions from the control system to perform control operations such as charging, discharging, and power regulation on the energy storage system. Depending on the application scenario, high-voltage boxes can be divided into many types, such as energy storage high-voltage boxes, electric vehicle high-voltage distribution boxes, etc.

[0003] When the high-voltage load circuit is cut off, the current will form an arc between the two poles of the switch. If the system is charged and discharged, the arc will continue, causing energy waste and equipment damage, and may even cause fire and personal injury.

[0004] like Figure 4 As shown, in the prior art, circuit breakers are usually used for arc protection. However, the use of circuit breakers for arc protection also has some disadvantages and limitations. For example, the increase in cost caused by adding circuit breakers, the size and weight of circuit breakers will limit the application scenarios of high-voltage boxes, and circuit breakers using special arc protection technology may require more complicated maintenance and repair procedures, etc. Summary of the invention

[0005] In view of this, the embodiments of this specification provide a control method for a high-voltage box and a high-voltage circuit applied to an energy storage system, which effectively reduces the voltage and current of the switch node of the high-voltage box and effectively prevents arcing in the circuit.

[0006] The embodiments of this specification provide the following technical solutions:

[0007] A high-voltage box applied to an energy storage system, the high-voltage box is connected between a battery cluster and a load of the energy storage system, and the high-voltage box includes:

[0008] Current sensor, fuse, total voltage collector, switch branch and arc protection element;

[0009] A current sensor is arranged in the high-voltage box. The current sensor can be arranged on the conductor of the positive electrode of the battery cluster. The current sensor is used to detect the current of the battery cluster. A fuse is arranged between the positive electrode of the battery cluster and the switch branch. The fuse is used to cut off the current when the cluster end current of the battery cluster exceeds the fuse value.

[0010] The input end of the total voltage collector is connected to the positive and negative electrodes of the battery cluster and the load respectively, and is used to collect the total voltage of the battery cluster and the total voltage of the load;

[0011] The switch branch includes a main branch and a pre-charging resistance branch arranged in parallel;

[0012] The main branch includes a first main branch and a second main branch, the first main branch is connected between the fuse and the positive electrode of the load, and the second main branch is connected between the negative electrode of the battery cluster and the negative electrode of the load;

[0013] The pre-charging resistance branch includes a first pre-charging resistance branch and a second pre-charging resistance branch, the first pre-charging resistance branch is connected between the fuse and the positive electrode of the load, and the second pre-charging resistance branch is connected between the negative electrode of the battery cluster and the negative electrode of the load;

[0014] The arc-proof element is arranged on the main branch or the pre-charging resistance branch, and the arc-proof element is used to eliminate the loop arc caused when the main branch is disconnected.

[0015] Further, an arc-proof element is arranged on the main branch, and the arc-proof element includes a first arc-proof element and a second arc-proof element. The first arc-proof element is arranged on the first main branch, and the first arc-proof element is connected between the fuse and the positive pole of the load. The first arc-proof element is the first main branch switch K1. The second arc-proof element is arranged on the second main branch, and the second arc-proof element is connected between the negative pole of the battery cluster and the negative pole of the load. The second arc-proof element is the second main branch switch K3.

[0016] Furthermore, the first main branch switch K1 and the first main branch switch K3 are both air switches or circuit breaker switches with arc protection capability.

[0017] Further, an arc protection element is arranged on the pre-charging resistance branch, the arc protection element includes a third arc protection element and a fourth arc protection element, the third arc protection element is arranged on the first pre-charging resistance branch, the input end of the first branch relay Q2 is connected to the fuse, the output end of the first branch relay Q2 is connected to the input end of the third arc protection element, and the input and output ends of the third arc protection element are connected to the positive electrode of the load;

[0018] The fourth arc-proof element is arranged on the second pre-charging resistance branch, the input end of the second branch relay Q4 is connected to the negative electrode of the battery cluster, the output end of the second branch relay Q4 is connected to the input end of the fourth arc-proof element, the input and output ends of the fourth arc-proof element are connected to the negative electrode of the load, and the third arc-proof element and the fourth arc-proof element are both PTC resistors.

[0019] Furthermore, the resistance value and rated power of the PTC resistor are determined according to the current capacity of the energy storage system and the multiple of the charge and discharge current.

[0020] Furthermore, the high-voltage box used in the energy storage system also includes:

[0021] The filter absorption branch is connected in parallel with the pre-charge resistance branch, and the filter absorption branch is used to absorb the peak current generated by the high-voltage circuit in the high-voltage box.

[0022] Further, the filter absorption branch includes a first filter absorption branch and a second filter absorption branch, the first filter absorption branch includes a first capacitor C1 and a third resistor R3, a first end of the first capacitor C1 is connected to the fuse, a second end of the first capacitor C1 is connected to a first end of the third resistor R3, and a second end of the third resistor R3 is connected to the positive electrode of the load;

[0023] The second filtering and absorbing branch includes a second capacitor C2 and a fourth resistor R4, wherein a first end of the second capacitor C2 is connected to the negative electrode of the battery cluster, a second end of the second capacitor C2 is connected to a first end of the fourth resistor R4, and a second end of the fourth resistor R4 is connected to the negative electrode of the load.

[0024] A control method for a high-voltage circuit, the control method uses a high-voltage box to open or close the high-voltage circuit, comprising:

[0025] Determine whether the arc protection element is set on the main branch or on the pre-charge resistor branch;

[0026] If the arc protection element is arranged on the main branch, the high voltage circuit is opened or closed by the first control method;

[0027] If the arc protection element is arranged on the pre-charging resistor branch, the high voltage circuit is opened or closed by the second control method.

[0028] Further, the high-voltage circuit is opened or closed by a first control method, including:

[0029] When closing the high-voltage circuit, first close the branch relay of the pre-charge resistance branch, and then close the arc-proof element of the main branch. The arc-proof element is an air switch or circuit breaker switch with arc-proof capability.

[0030] When disconnecting the high-voltage circuit, first close the branch relay of the pre-charging resistance branch, then disconnect the arc protection element of the main branch, and finally disconnect the branch relay of the pre-charging resistance branch;

[0031] When the main branch circuit is overcurrent or the energy storage system is short-circuited, the arc protection element of the main branch circuit is disconnected.

[0032] Furthermore, the high-voltage circuit is opened or closed by a second control method, including:

[0033] When the high-voltage circuit is closed, after the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are closed, the first main relay Q1 and the second main relay Q3 of the main branch are closed, and the arc protection element is a PTC resistor;

[0034] When disconnecting the high-voltage circuit, after closing the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch, disconnect the first main relay Q1 and the second main relay Q3 of the main branch, and finally disconnect the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch;

[0035] When the main branch is overcurrent or the energy storage system is short-circuited, the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are closed at the moment, and then the first main relay Q1 and the second main relay Q3 of the main branch are directly disconnected, and then the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are quickly turned off.

[0036] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0037] The voltage and current of the switch node of the high-voltage box are effectively reduced, and arcing of the circuit can be effectively prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 is a schematic diagram of the overall structure of the high-voltage box of the first embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the overall structure of a high-voltage box according to a second embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of the overall structure of a high-voltage box according to a third embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of the overall structure of a high-voltage box in the prior art. DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0044] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] In current energy storage and automotive applications, the high-voltage box used to connect and disconnect the high-voltage circuit in the prior art is as follows: Figure 4 shown.

[0046] The high voltage box includes: a current sensor, a fuse, a total voltage collector, a switch branch and an arc protection element.

[0047] The current sensor is arranged in the high-voltage box. The current sensor can be arranged on the conductor of the positive electrode of the battery cluster. The current sensor is used to detect the current of the battery cluster. The fuse is arranged between the positive electrode of the battery cluster and the switch branch. The fuse is used to cut off the current when the cluster end current of the battery cluster exceeds the fuse value.

[0048] The input end of the total voltage collector is connected to the positive and negative electrodes of the battery cluster and the load respectively, and is used to collect the total voltage of the battery cluster and the total voltage of the load.

[0049] The switch branch includes a main branch and a pre-charging resistance branch arranged in parallel. The main branch includes a first main branch and a second main branch, the first main branch is connected between the fuse and the positive electrode of the load, and the second main branch is connected between the negative electrode of the battery cluster and the negative electrode of the load. The first main branch includes a first main relay Q1, and the second main branch includes a second main relay Q3.

[0050] The pre-charging resistance branch includes a first pre-charging resistance branch and a second pre-charging resistance branch, the first pre-charging resistance branch is connected between the fuse and the positive electrode of the load, and the second pre-charging resistance branch is connected between the negative electrode of the battery cluster and the negative electrode of the load. The first pre-charging resistance branch includes a first branch relay Q2 and a first pre-charging loop resistor connected in series. The second pre-charging resistance branch includes a second branch relay Q4 and a second pre-charging loop resistor connected in series.

[0051] The arc protection element is a circuit breaker arranged between the positive and negative terminals of the load.

[0052] The high-voltage circuit is a circuit between the battery cluster and the load, including a main branch, a pre-charging resistance branch, etc. (in the third embodiment, it also includes a filtering absorption branch).

[0053] Using the high-voltage box of the prior art to control the high-voltage circuit includes the following steps:

[0054] 1. When closing the high-voltage circuit, the main branch and the pre-charging resistor branch are both in the disconnected state. First, close the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistor branch where the pre-charging circuit resistor is located, and then close the first main relay Q1 and the second main relay Q3 of the main branch to prevent the voltage difference between the two ends and the impact current from being too large at the moment of closing the main branch, which may damage the device;

[0055] 2. When the high-voltage circuit is disconnected, the first main relay Q1 and the second main relay Q3 of the main branch are closed, and the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch are disconnected. First, the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch where the pre-charge circuit resistor is located are closed to pre-charge the resistor, and then the first main relay Q1 and the second main relay Q3 of the main branch are disconnected, and then the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch are disconnected to prevent the main branch from being disconnected and causing arcing due to excessive pressure difference at the moment of disconnection, which may cause damage to the device;

[0056] 3. When the system fails or is short-circuited, the main branch is overcurrent or the system is short-circuited, and the first main relay Q1 and the second main relay Q3 of the main branch need to be directly disconnected. At this time, disconnecting the main branch will cause arcing, so it is necessary to directly use a circuit breaker to disconnect the high-voltage circuit to prevent arcing in the system circuit.

[0057] The existing pre-charging resistor branch can solve the problem of large current caused by the load end capacitance during the conventional power on and off process, but it cannot solve the arcing problem caused by the disconnection of the main circuit in an emergency. For example, during the power on and off process, the arcing may be caused by weakened insulation or sudden changes in voltage and current. Therefore, the present invention proposes three solutions.

[0058] like Figure 1 As shown, in the first embodiment of the present invention, the first main relay Q1 and the second main relay Q3, which originally do not have the arc protection shutoff capability, are replaced with switches with arc protection capability (such as circuit breakers, circuit breaker switches, etc.), and the circuit breakers are removed.

[0059] Specifically, the arc protection element is arranged on the main branch, and the arc protection element includes a first arc protection element and a second arc protection element. The first arc protection element is arranged on the first main branch, the first arc protection element is connected between the fuse and the positive pole of the load, and the first arc protection element is the first main branch switch K1, and the second arc protection element is arranged on the second main branch, the second arc protection element is connected between the negative pole of the battery cluster and the negative pole of the load, and the second arc protection element is the second main branch switch K3.

[0060] In the first embodiment, the pre-charging resistance branch may be a pre-charging resistance branch in the prior art. That is, the pre-charging resistance branch includes a first pre-charging resistance branch and a second pre-charging resistance branch, the first pre-charging resistance branch is connected between the fuse and the positive electrode of the load, and the second pre-charging resistance branch is connected between the negative electrode of the battery cluster and the negative electrode of the load. The first pre-charging resistance branch includes a first branch relay Q2 and a first pre-charging loop resistor connected in series. The second pre-charging resistance branch includes a second branch relay Q4 and a second pre-charging loop resistor connected in series.

[0061] In the first embodiment, the arc protection elements are the first main branch switch K1 and the second main branch switch K3.

[0062] Using the high-voltage box of the first embodiment to control the high-voltage circuit includes the following steps:

[0063] 1. When closing the high-voltage circuit, the main branch and the pre-charging resistor branch are both in the disconnected state. First, close the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistor branch where the pre-charging circuit resistor is located, and then close the first main branch switch K1 and the second main branch switch K3 of the main branch to prevent the voltage difference between the two ends and the impact current from being too large when the main branch is closed, which may damage the device;

[0064] 2. When the high-voltage circuit is disconnected, the first main branch switch K1 and the second main branch switch K3 of the main branch are closed, and the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch are disconnected. First, the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch where the pre-charge loop resistor is located are closed to pre-charge the resistor, and then the first main branch switch K1 and the second main branch switch K3 of the main branch are disconnected, and then the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistor branch are disconnected to prevent the main branch from being disconnected and causing arcing due to excessive pressure difference at the moment of disconnection, which may cause damage to the device;

[0065] 3. When the system fails or is short-circuited, the main branch is overcurrent or the system is short-circuited, the first main branch switch K1 and the second main branch switch K3 of the main branch are directly disconnected. Because the first main branch switch K1 and the second main branch switch K3 have arc protection capabilities, they can be directly disconnected.

[0066] Compared with the arc protection solution in the prior art, the first embodiment is equivalent to removing the circuit breaker and adding switches with arc protection capability to the positive and negative main circuits.

[0067] However, circuit breaker arc protection devices (i.e. switches with arc protection capabilities) are usually expensive and usually require manual closing after disconnection. Therefore, it is proposed to use PTC as a pre-charge to prevent arcing.

[0068] like Figure 2 As shown, in the second embodiment of the present invention, the PTC resistor causes the resistance value to rise under high current, which can effectively reduce the loop current, thereby avoiding arcing caused by the disconnection of the contactor under high current. The use of PTC resistors to prevent arcing can reduce the number of circuit breakers.

[0069] Specifically, the arc-proof element is arranged on the pre-charging resistance branch, and the arc-proof element includes a third arc-proof element and a fourth arc-proof element. The third arc-proof element is arranged on the first pre-charging resistance branch, the input end of the first branch relay Q2 is connected to the fuse, the output end of the first branch relay Q2 is connected to the input end of the third arc-proof element, and the input and output ends of the third arc-proof element are connected to the positive electrode of the load. The fourth arc-proof element is arranged on the second pre-charging resistance branch, the input end of the second branch relay Q4 is connected to the negative electrode of the battery cluster, the output end of the second branch relay Q4 is connected to the input end of the fourth arc-proof element, and the input and output ends of the fourth arc-proof element are connected to the negative electrode of the load, and the third arc-proof element and the fourth arc-proof element are both PTC resistors.

[0070] Specifically, the resistance value and rated power of the PTC resistor are determined according to the current capacity of the energy storage system and the multiple of the charge and discharge current.

[0071] Except for the pre-charging resistor branch, other structures of the second embodiment are the same as those of the first embodiment.

[0072] Using the high-voltage box of the second embodiment to control the high-voltage circuit includes the following steps:

[0073] 1. When closing the high-voltage circuit, the main branch and the pre-charging resistor branch are both in the disconnected state. First, close the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistor branch where the PTC resistor is located, and then close the first main relay Q1 and the second main relay Q3 of the main branch to prevent the voltage difference between the two ends and the impact current from being too large when the main branch is closed, which may damage the device;

[0074] 2. When the high-voltage circuit is disconnected, the first main relay Q1 and the second main relay Q3 of the main branch are closed, and the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistance branch where the PTC resistor is located are disconnected. First, close the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistance branch where the pre-charge circuit resistor is located, and then disconnect the first main relay Q1 and the second main relay Q3 of the main branch, and then disconnect the first branch relay Q2 and the second branch relay Q4 of the pre-charge resistance branch to prevent the main branch from being disconnected and causing arcing due to excessive pressure difference at the moment of disconnection, causing damage to the device;

[0075] 3. When the system fails or is short-circuited, the first main relay Q1 and the second main relay Q3 of the main branch are closed, and the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch where the PTC resistor is located are disconnected. It is necessary to urgently disconnect the first main relay Q1 and the second main relay Q3 of the main branch. At this time, at the moment of closing the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch, the voltage across the first main relay Q1 and the second main relay Q3 of the main branch is already very small, and the disconnection condition is ready, and they can be directly disconnected. At the same time, when the energy storage system is short-circuited or other high current conditions occur, the greater the current, the higher the PTC heats up, and the greater the resistance value of the PTC resistor, which can reduce the system current in a short time, and then quickly shut down the first main relay Q1 and the second main relay Q3 to prevent arcing.

[0076] In addition, according to different system voltage and system current levels, the withstand voltage level, power level, etc. of each device in the high-voltage box can be improved. For example, in the 1500VDC / 0.5C system, 1500VDC / 1C system, 1500VDC / 1C system, and 1500VDC / 1C system, different power devices are used, which can effectively reduce costs.

[0077] like Figure 3 As shown, in the third embodiment of the present invention, a filter absorption branch is connected in parallel to the pre-charging resistance branch of the second embodiment, wherein the filter absorption branch is used to absorb the peak current generated by the switch and the like.

[0078] Specifically, the filter absorption branch includes a first filter absorption branch and a second filter absorption branch. The first filter absorption branch includes a first capacitor C1 and a third resistor R3. The first end of the first capacitor C1 is connected to the fuse, the second end of the first capacitor C1 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is connected to the positive electrode of the load.

[0079] The second filtering and absorbing branch includes a second capacitor C2 and a fourth resistor R4, wherein a first end of the second capacitor C2 is connected to the negative electrode of the battery cluster, a second end of the second capacitor C2 is connected to a first end of the fourth resistor R4, and a second end of the fourth resistor R4 is connected to the negative electrode of the load.

[0080] Except for the filtering and absorbing branch, the other structures of the third embodiment are the same as those of the second embodiment. The steps of controlling the high voltage circuit using the high voltage box of the third embodiment are also the same as those of controlling the high voltage circuit using the high voltage box of the second embodiment.

[0081] In the third embodiment, the arc protection element is a PTC resistor.

[0082] Beneficial effects of the embodiments of the present invention:

[0083] In the first embodiment of the present invention, switches with arc protection capability are added to both the positive and negative main circuits, and a circuit breaker is not required, which can effectively prevent arcing. The branch where the PTC resistor is located in the second embodiment of the present invention can be used as a pre-charging resistor branch under normal circumstances to achieve reliable operation of the upper and lower points of the energy storage system. When the system is abnormal, the pre-charging resistor branch where the PTC resistor is located is closed to disconnect the main circuit. The greater the current of the energy storage system, the greater the heat generated by the PTC resistor, and the higher the resistance value of the PTC resistor, which can effectively reduce the current of the energy storage system, prevent arcing, and effectively improve the life of the main circuit contactor switch (relay), and improve the service life of the fuse. At the same time, there is no need to use a circuit breaker, which reduces costs. The filter absorption branch added in the third embodiment of the present invention can be used to absorb the peak current generated by the switch, etc., so that the safety of the high-voltage box is further enhanced.

[0084] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other, and with each other.

Claims

1. A high-voltage box used in an energy storage system, characterized in that: The high-voltage box is connected between the battery cluster and the load of the energy storage system, and the high-voltage box includes: Current sensor, fuse, total voltage collector, switch branch and arc protection element; The current sensor is arranged in the high voltage box and is used to detect the current value of the battery cluster; The fuse is arranged between the positive electrode of the battery cluster and the switch branch, and is used to cut off the current when the cluster end current of the battery cluster exceeds the fusing value of the fuse; The input end of the total voltage collector is connected to the positive and negative electrodes of the battery cluster and the load respectively, and is used to collect the total voltage of the battery cluster and the total voltage of the load; The switch branch comprises a main branch and a pre-charging resistance branch arranged in parallel; The main branch includes a first main branch and a second main branch, the first main branch is connected between the fuse and the positive electrode of the load, and the second main branch is connected between the negative electrode of the battery cluster and the negative electrode of the load; The pre-charging resistance branch includes a first pre-charging resistance branch and a second pre-charging resistance branch, the first pre-charging resistance branch is connected between the fuse and the positive electrode of the load, and the second pre-charging resistance branch is connected between the negative electrode of the battery cluster and the negative electrode of the load; The arc-proof element is arranged on the main branch or the pre-charging resistance branch, and is used to eliminate loop arcing caused when the main branch is disconnected.

2. The high-voltage box used in the energy storage system according to claim 1, characterized in that: The arc-proof element is arranged on the main branch, and the arc-proof element includes a first arc-proof element and a second arc-proof element. The first arc-proof element is arranged on the first main branch, and the first arc-proof element is connected between the fuse and the positive pole of the load. The first arc-proof element is a first main branch switch K1. The second arc-proof element is arranged on the second main branch, and the second arc-proof element is connected between the negative pole of the battery cluster and the negative pole of the load. The second arc-proof element is a second main branch switch K3.

3. The high-voltage box used in the energy storage system according to claim 2, characterized in that: The first main branch switch K1 and the second main branch switch K3 are both air switches or circuit breaker switches with arc protection capability.

4. The high-voltage box used in the energy storage system according to claim 1, characterized in that: The arc-proof element is arranged on the pre-charging resistance branch, and the arc-proof element includes a third arc-proof element and a fourth arc-proof element. The third arc-proof element is arranged on the first pre-charging resistance branch, the input end of the first branch relay Q2 is connected to the fuse, the output end of the first branch relay Q2 is connected to the input end of the third arc-proof element, and the output end of the third arc-proof element is connected to the positive electrode of the load; The fourth arc-proof element is arranged on the second pre-charging resistance branch, the input end of the second branch relay Q4 is connected to the negative electrode of the battery cluster, the output end of the second branch relay Q4 is connected to the input end of the fourth arc-proof element, the output end of the fourth arc-proof element is connected to the negative electrode of the load, and the third arc-proof element and the fourth arc-proof element are both PTC resistors.

5. The high-voltage box used in the energy storage system according to claim 4, characterized in that: The resistance value and rated power of the PTC resistor are determined according to the current capacity of the energy storage system and the multiple of the charge and discharge current.

6. The high-voltage box used in the energy storage system according to claim 4 or 5, characterized in that: Also includes: A filter absorption branch, the filter absorption branch is connected in parallel with the pre-charging resistance branch, and the filter absorption branch is used to absorb the peak current generated by the high-voltage circuit in the high-voltage box.

7. The high-voltage box used in the energy storage system according to claim 6, characterized in that: The filter absorption branch comprises a first filter absorption branch and a second filter absorption branch, the first filter absorption branch is connected in parallel with the first pre-filling resistance branch, and the second filter absorption branch is connected in parallel with the second pre-filling resistance branch; The first filtering absorption branch includes a first capacitor C1 and a third resistor R3, wherein a first end of the first capacitor C1 is connected to the first pre-charging resistor branch, a second end of the first capacitor C1 is connected to a first end of the third resistor R3, and a second end of the third resistor R3 is connected to the first pre-charging resistor branch; The second filtering absorption branch includes a second capacitor C2 and a fourth resistor R4, the first end of the second capacitor C2 is connected to the second pre-charge resistor branch, the second end of the second capacitor C2 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is connected to the second pre-charge resistor branch.

8. A control method for a high-voltage circuit, the control method using the high-voltage box according to any one of claims 1 to 7 to open or close the high-voltage circuit, characterized in that: include: Determine whether the arc protection element is arranged on the main branch or on the pre-charging resistance branch; If the arc protection element is arranged on the main branch, the high voltage circuit is opened or closed by the first control method; If the arc protection element is arranged on the pre-charging resistor branch, the high voltage circuit is opened or closed by the second control method.

9. The high-voltage circuit control method according to claim 8, characterized in that: The high-voltage circuit is opened or closed by a first control method, including: When closing the high-voltage circuit, first close the branch relay of the pre-charging resistance branch, and then close the arc-proof element of the main branch, the arc-proof element is an air switch or a circuit breaker switch with arc-proof capability; When disconnecting the high-voltage circuit, first close the branch relay of the pre-charging resistance branch, then disconnect the arc-proof element of the main branch, and finally disconnect the branch relay of the pre-charging resistance branch; When the main branch circuit is overcurrent or the energy storage system is short-circuited, the arc protection element of the main branch circuit is disconnected.

10. The high-voltage circuit control method according to claim 8, characterized in that: The high-voltage circuit is opened or closed by the second control method, including: When the high-voltage circuit is closed, after the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are closed, the first main relay Q1 and the second main relay Q3 of the main branch are closed, and the arc protection element is a PTC resistor; When disconnecting the high-voltage circuit, after closing the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch, disconnect the first main relay Q1 and the second main relay Q3 of the main branch, and finally disconnect the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch; When the main branch is overcurrent or the energy storage system is short-circuited, the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are closed at the moment, and then the first main relay Q1 and the second main relay Q3 of the main branch are directly disconnected, and then the first branch relay Q2 and the second branch relay Q4 of the pre-charging resistance branch are quickly turned off.

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