Insulation protection circuit, insulation protection method, and energy storage system

Abstract

An insulation protection circuit, an insulation protection method, and an energy storage system. The energy storage system comprises an energy storage battery (100), which comprises a plurality of battery components (110) sequentially connected in series. The insulation protection circuit comprises a current limiting module (200). Housings of the plurality of battery components are grounded by means of the current limiting module, and the current limiting module performs current limiting on a passing current, such that in the case of an insulation failure, the energy storage battery limits a current at a deterioration failure location, so as to prevent the occurrence of thermal damage to an insulating material at a deterioration location of the energy storage battery, restrict the tendency of further deterioration of the insulating material, and avoid a thermal runaway problem caused by intense discharge, thereby improving the safety of the energy storage battery.

Description

Insulation protection circuit, insulation protection method and energy storage system

[0001] The present application refers to the Chinese Patent Application No. 202411302721.8 entitled "Insulation protection circuit, insulation protection method and energy storage system" filed on September 18, 2024, which is incorporated by reference in its entirety into the present application. TECHNICAL FIELD

[0002] The present application relates to the technical field of energy storage systems, in particular to an insulation protection circuit, an insulation protection method and an energy storage system. BACKGROUND

[0003] In an electrochemical energy storage system, factors such as damage to the blue film of the battery cell, intrusion of foreign matter, polarization of insulation materials, etc. can cause system insulation abnormalities, and in severe cases, can lead to battery thermal failure, equipment damage, electric shock, etc. Therefore, detecting and locating the insulation performance of the system has always been a hot issue in the research of the battery management system (BMS).

[0004] In related technologies, the balanced bridge insulation detection method is widely used in battery system insulation detection due to its simple structure and easy implementation. However, in the case of double-point insulation abnormalities, the traditional balanced bridge insulation detection scheme cannot achieve double-point failure protection, which can cause the battery cell to discharge violently, and further cause thermal runaway. TECHNICAL PROBLEM

[0005] The present application provides an insulation protection circuit, an insulation protection method and an energy storage system, which can solve the problem of safety hazards in the failure protection scheme of the balanced bridge insulation detection scheme in related technologies. TECHNICAL SOLUTION

[0006] In view of the above problems, the present application provides an insulation protection circuit, an insulation protection method and an energy storage system, which can solve the problem of safety hazards in the failure protection scheme of the balanced bridge insulation detection scheme in related technologies.

[0007] The first aspect of the embodiments of the present application provides an insulation protection circuit for insulating and protecting an energy storage battery, the energy storage battery comprising a plurality of battery assemblies connected in series, and the insulation protection circuit comprising:

[0008] A current limiting module connected to the housings of the plurality of battery assemblies, the housings of the plurality of battery assemblies being grounded through the current limiting module, and the housings of each battery assembly being connected to each other through the current limiting module.

[0009] In the technical scheme of the embodiment of the application, when insulation failure occurs in the shell of any one of the plurality of battery assemblies, the current of the loop formed by the battery assembly and the ground wire can be limited by the current limiting module, the current at the deterioration failure position of the energy storage battery can be limited in the case of insulation failure, the problem of thermal damage of the insulation material at the deterioration position of the energy storage battery can be prevented, the further deterioration trend of the insulation material is limited, the thermal runaway problem caused by severe discharge can be avoided, and the safety of the energy storage battery is improved.

[0010] In some embodiments, the shells of the respective battery assemblies are connected to each other through the current limiting module.

[0011] In the technical scheme of the embodiment of the application, the shells of the respective battery assemblies are connected to each other through the current limiting module, and the current flowing through the current limiting module is limited by the current limiting module in the case of double-point insulation failure of the energy storage battery, so that the thermal runaway problem caused by severe discharge in the case of double-point insulation failure of the battery can be solved, and the safety of the system is improved.

[0012] In some embodiments, the insulation protection circuit comprises:

[0013] The current sampling module is connected in series with the current limiting module and is configured to sample the current flowing through the current limiting module to obtain a ground wire sampling current.

[0014] The main control module is connected with the current sampling module and is configured to determine the insulation protection state of the energy storage battery according to the ground wire sampling current.

[0015] In the technical scheme of the embodiment of the application, the current flowing through the current limiting module is sampled by the current sampling module to obtain a ground wire sampling current, and the main control module determines the insulation protection state of the energy storage battery according to the ground wire sampling current. If the energy storage battery has insulation failure, the current flowing through the current limiting module increases. In this way, the insulation protection state of the energy storage battery can be monitored by judging the sampled current sampling signal.

[0016] In some embodiments, the current limiting module comprises one or more resistance units, and the shells of the plurality of battery assemblies are connected to the current sampling module through the corresponding resistance units.

[0017] In the technical scheme of the embodiment of the application, the current flowing through the current limiting module is sampled by the current sampling module to obtain a ground wire sampling current, and the main control module determines the insulation protection state of the energy storage battery according to the ground wire sampling current. If the energy storage battery has insulation failure, the current flowing through the current limiting module increases. In this way, the insulation protection state of the energy storage battery can be monitored by judging the sampled current sampling signal.

[0018] In some embodiments, the insulation protection circuit further comprises an insulation detection module connected to the positive pole of the energy storage battery, the negative pole of the energy storage battery and the ground wire, the insulation detection module being controlled by the master control module and used for detecting the inner equivalent insulation resistance of the energy storage battery.

[0019] The master control module determines the insulation protection state of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

[0020] In the technical scheme of the embodiments, the inner equivalent insulation resistance of the energy storage battery is detected by the insulation detection module, and the master control module determines the insulation protection state of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery. When insulation failure occurs in the energy storage battery, the inner equivalent insulation resistance of the energy storage battery will decrease due to the insulation failure of the energy storage battery. Therefore, the inner equivalent insulation resistance of the energy storage battery is compared with the preset threshold resistance, and when the inner equivalent insulation resistance of the energy storage battery is lower than the preset threshold resistance, it can be determined that the insulation failure occurs in the energy storage battery.

[0021] In some embodiments, the insulation detection module comprises:

[0022] A first insulation detection unit connected between the positive pole of the energy storage battery and the current sampling module;

[0023] A second insulation detection unit connected between the negative pole of the energy storage battery and the current sampling module.

[0024] In the technical scheme of the embodiments, the first insulation detection unit is connected between the positive pole of the energy storage battery and the current sampling module, and the second insulation detection unit is connected between the negative pole of the energy storage battery and the current sampling module. By controlling the switching state of the first insulation detection unit and the second insulation detection unit, the voltage between the positive pole of the energy storage battery and the ground wire and the voltage between the negative pole of the energy storage battery and the ground wire can be sampled, so that the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire are obtained based on the sampling voltage. The inner equivalent insulation resistance of the energy storage battery includes the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire. The master control module determines the insulation protection state of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery. When insulation failure occurs in the energy storage battery, the inner equivalent insulation resistance of the energy storage battery will decrease due to the insulation failure of the energy storage battery. Therefore, the inner equivalent insulation resistance of the energy storage battery is compared with the preset threshold resistance, and when the inner equivalent insulation resistance of the energy storage battery is lower than the preset threshold resistance, it can be determined that the insulation failure occurs in the energy storage battery.

[0025] In some embodiments, the first insulation detection unit comprises a first switch and a first resistor, and the first switch and the first resistor are connected in series and between the positive pole of the energy storage battery and the current sampling module.

[0026] In some embodiments, the second insulation detection unit comprises a second switch and a second resistor, and the second switch and the second resistor are connected in series and between the negative pole of the energy storage battery and the current sampling module.

[0027] In some embodiments, the working states of the first insulation detection unit and the second insulation detection unit are controlled by the master control module.

[0028] In the technical scheme of the embodiments of the present application, the first switch and the first resistor are connected in series, the second switch and the second resistor are connected in series, and the circuit after the first switch and the first resistor are connected in series is connected in parallel with the equivalent circuit between the cabinet shell where the energy storage battery is located and the positive DC bus, and the circuit after the second switch and the second resistor are connected in series is connected in parallel with the equivalent circuit between the cabinet shell where the energy storage battery is located and the negative DC bus. The positive pole of the energy storage battery is connected with the positive DC bus, and the negative pole of the energy storage battery is connected with the negative DC bus. By controlling the switching states of the first switch and the second switch through the master control module, the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire can be obtained. By comparing the first equivalent insulation resistance and the second equivalent insulation resistance of the energy storage battery with the preset threshold resistance, when the inner equivalent insulation resistance of the energy storage battery is lower than the preset threshold resistance, it can be determined that the energy storage battery has insulation failure.

[0029] In some embodiments, the master control module is further configured to detect the inner equivalent insulation resistance of the energy storage battery before high-voltage power-on of the energy storage battery, and control the high-voltage power-on of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

[0030] The inner equivalent insulation resistance of the energy storage battery comprises the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire.

[0031] In the technical scheme of the embodiments of the present application, the inner equivalent insulation resistance of the energy storage battery comprises the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire. The inner equivalent insulation resistance of the energy storage battery comprises the first equivalent insulation resistance between the positive pole of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative pole of the energy storage battery and the ground wire. Detecting the inner equivalent insulation resistance of the energy storage battery before power-on and controlling the high-voltage power-on of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery can avoid the problem of severe discharge of the energy storage battery when the energy storage battery is directly powered on at high voltage in the presence of insulation failure, and improve the safety of high-voltage power-on operation.

[0032] In some embodiments, the master module is further configured to detect the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance when the internal side equivalent insulation resistance of the energy storage battery is greater than the first threshold resistance, and control the high voltage power-on of the energy storage battery when the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than the second threshold resistance.

[0033] In the technical solution of the embodiments of the present application, if the internal side equivalent insulation resistance of the energy storage battery is greater than the first threshold resistance, it indicates that the internal side equivalent insulation resistance of the energy storage battery is within the safe resistance range. In order to further detect the external side equivalent insulation resistance of the energy storage battery, the positive bus side equivalent insulation resistance can be detected by turning on the main positive relay and turning off the main negative relay, and the negative bus side equivalent insulation resistance can be detected by turning on the main negative relay and turning off the main positive relay. If the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than the second threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus or the negative DC bus and the shell of the electric cabinet corresponding to the energy storage battery is within the safe threshold range, and the equivalent insulation resistance between the load positive bus or the load negative bus and the electric platform of the energy storage power station corresponding to the energy storage battery is within the safe threshold range, and the energy storage battery can normally execute the high voltage power-on process.

[0034] In some embodiments, the master module is further configured to generate a first alarm signal when the internal side equivalent insulation resistance of the energy storage battery is equal to or less than the first threshold resistance.

[0035] In the technical solution of the embodiments of the present application, if the internal side equivalent insulation resistance of the energy storage battery is equal to or less than the first threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus between the positive electrode of the energy storage battery and the main positive relay and the shell is outside the safe threshold range, and there is a risk of insulation failure. Therefore, the master module generates a first alarm signal to remind the user to detect the energy storage battery.

[0036] In some embodiments, the master module is specifically configured to detect the positive bus side equivalent insulation resistance after the main positive relay is turned on and the main negative relay is turned off, and determine the insulation protection state of the energy storage battery according to the resistance value of the positive bus side equivalent insulation resistance.

[0037] In the technical solution of the embodiment of the application, in the case that the main positive relay is turned on and the main negative relay is turned off, there is a first power station equivalent insulation resistance between the positive direct current bus and the electric platform of the energy storage power station, the first power station equivalent insulation resistance is equivalent in parallel with the first equivalent insulation resistance, and the equivalent resistance after parallel connection is the positive bus side equivalent insulation resistance. The main control module can determine the insulation protection state of the energy storage battery according to the resistance value of the positive bus side equivalent insulation resistance. For example, the main control module determines whether the positive bus side equivalent insulation resistance and / or the second equivalent insulation resistance exceeds the corresponding threshold range in the case that the main positive relay is turned on and the main negative relay is turned off. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistances between the housings of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding direct current buses are all within the safety threshold range.

[0038] In some embodiments, the main control module is further configured to generate a second alarm signal in the case that the resistance value of the positive bus side equivalent insulation resistance after the main positive relay is closed is equal to or less than the second threshold resistance.

[0039] In the technical solution of the embodiment of the application, in the case that the main positive relay is turned on and the main negative relay is turned off, if the resistance value of the positive bus side equivalent insulation resistance is equal to or less than the second threshold resistance, it indicates that the equivalent insulation resistances between the housings of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding direct current buses may exceed the safety threshold range, and the main control module generates a second alarm signal to remind the user to detect the housings of the energy storage battery, the energy storage cabinet and the energy storage power station.

[0040] In some embodiments, the main control module is specifically configured to detect the negative bus side equivalent insulation resistance after the main negative relay is turned on and the main positive relay is turned off, and control the main negative relay to be closed in the case that the resistance value of the negative bus side equivalent insulation resistance is greater than the second threshold resistance.

[0041] In the technical solution of the embodiment of the application, in the case that the main negative relay is turned on and the main positive relay is turned off, there is a second power station equivalent insulation resistance between the negative direct current bus and the electric platform of the energy storage power station, the second power station equivalent insulation resistance is equivalent in parallel with the second equivalent insulation resistance, and the equivalent resistance after parallel connection is the negative bus side equivalent insulation resistance. The main control module can determine the insulation protection state of the energy storage battery according to the resistance value of the negative bus side equivalent insulation resistance. For example, the main control module determines whether the negative bus side equivalent insulation resistance and / or the first equivalent insulation resistance exceeds the corresponding threshold range in the case that the main positive relay is turned off and the main negative relay is turned on. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistances between the housings of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding direct current buses are all within the safety threshold range.

[0042] In some embodiments, the master module is further configured to detect the inner equivalent insulation resistance of the energy storage battery in the single-point insulation failure state, and locate the position of the single-point insulation failure of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery in the single-point insulation failure state.

[0043] In the technical solution of the embodiments of the present application, when the energy storage battery has a single-point insulation failure or is in a deteriorated working condition, the inner equivalent insulation resistance of the energy storage battery in the single-point insulation failure state is detected, and the position of the single-point insulation failure of the energy storage battery is located according to the inner equivalent insulation resistance of the energy storage battery in the single-point insulation failure state, so as to timely remind the user of the insulation failure position, and improve the troubleshooting efficiency of the energy storage battery.

[0044] In some embodiments, the master module is specifically configured to, when the first insulation detection unit and the second insulation detection unit are in the conducting state, sample the voltage between the positive electrode of the energy storage battery and the ground wire to obtain a first sampling voltage, sample the voltage between the negative electrode of the energy storage battery and the ground wire to obtain a second sampling voltage, control the first insulation detection unit to be in the conducting state and the second insulation detection unit to be in the off state when the first sampling voltage is less than the second sampling voltage, sample the voltage between the positive electrode of the energy storage battery and the ground wire to obtain a third sampling voltage, sample the voltage between the negative electrode of the energy storage battery and the ground wire to obtain a fourth sampling voltage, and calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage, and the ground wire sampling current; the inner equivalent insulation resistance of the energy storage battery includes a first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and a second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire.

[0045] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent in parallel with the first equivalent insulation resistor, and the second insulation detection unit is equivalent in parallel with the second equivalent insulation resistor. In the first sampling stage, the first insulation detection unit and the second insulation detection unit are controlled to be in the conducting state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a second sampling voltage. In the second sampling stage, if the first sampling voltage is less than the second sampling voltage, the first insulation detection unit is controlled to be in the conducting state, the second insulation detection unit is controlled to be in the off state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a third sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a fourth sampling voltage. In this way, the inside equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current, which can not only improve the accuracy of the inside equivalent insulation resistance of the energy storage battery, but also determine whether the energy storage battery has insulation failure based on the inside equivalent insulation resistance.

[0046] In some embodiments, the master control module is further configured to, in the case that the first sampling voltage is greater than or equal to the second sampling voltage, control the first insulation detection unit to be in the off state, control the second insulation detection unit to be in the conducting state, sample the voltage between the positive electrode of the energy storage battery and the ground wire to obtain a fifth sampling voltage, sample the voltage between the negative electrode of the energy storage battery and the ground wire to obtain a sixth sampling voltage, and calculate the inside equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current.

[0047] In the technical solution of the embodiment, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the first sampling stage, the first insulation detection unit and the second insulation detection unit are controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a second sampling voltage. In the second sampling stage, if the first sampling voltage is greater than or equal to the second sampling voltage, the first insulation detection unit is controlled to be in the off state, the second insulation detection unit is controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a fifth sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a sixth sampling voltage. In this way, the internal equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current, which not only improves the accuracy of the internal equivalent insulation resistance of the energy storage battery, but also determines whether the energy storage battery has insulation failure based on the internal equivalent insulation resistance.

[0048] In some embodiments, the master control module is further configured to determine the single-point insulation failure position of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current.

[0049] In the technical solution of the embodiment, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the first sampling voltage is less than the second sampling voltage, the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery and the single-point insulation failure position can be calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current. Therefore, the specific single-point insulation failure position can be determined by the first voltage and the second voltage, and the efficiency of troubleshooting of the energy storage battery is improved.

[0050] In some embodiments, the master control module is further configured to determine the single-point insulation failure position of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current.

[0051] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent in parallel with the first equivalent insulation resistance, and the second insulation detection unit is equivalent in parallel with the second equivalent insulation resistance. In the case that the first sampling voltage is greater than or equal to the second sampling voltage, the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery and the single-point insulation failure position can be calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current. Therefore, the specific single-point insulation failure position can be determined through the first voltage and the second voltage, and the efficiency of troubleshooting of the energy storage battery is improved.

[0052] In some embodiments, the master control module is further configured to calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current, and determine the insulation deterioration degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

[0053] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent in parallel with the first equivalent insulation resistance, and the second insulation detection unit is equivalent in parallel with the second equivalent insulation resistance. In the case that the first sampling voltage is less than the second sampling voltage, the inner equivalent insulation resistance of the energy storage battery can be calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current. Under normal working conditions, the equivalent insulation resistance of the charging and discharging circuit and the shell is above tens of megohms due to the protection of the blue film and the insulation material of the energy storage battery. When insulation failure or deterioration occurs, the equivalent insulation resistance decreases. Therefore, the insulation deterioration severity can be evaluated according to the inner equivalent insulation resistance of the energy storage battery.

[0054] In some embodiments, the master control module is further configured to calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current, and determine the insulation deterioration degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

[0055] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent in parallel with the first equivalent insulation resistance, and the second insulation detection unit is equivalent in parallel with the second equivalent insulation resistance. In the case that the first sampling voltage is greater than or equal to the second sampling voltage, the inner equivalent insulation resistance of the energy storage battery can be calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current. Under normal working conditions, the equivalent insulation resistance of the charging and discharging circuit and the shell is above tens of megohms due to the protection of the blue film and the insulation material of the energy storage battery. When insulation failure or deterioration occurs, the equivalent insulation resistance decreases. Therefore, the insulation deterioration severity can be evaluated according to the inner equivalent insulation resistance of the energy storage battery.

[0056] The second aspect of the embodiments of the present application provides an insulation protection method for insulating and protecting an energy storage battery, the energy storage battery comprising a plurality of battery assemblies connected in series, and the insulation protection method comprising:

[0057] The housings of the plurality of battery assemblies are grounded through the current limiting module.

[0058] In the technical solution of the embodiments of the present application, when insulation failure occurs in the housing of any one of the battery assemblies, the current limiting module can limit the current of the loop formed by the battery assembly and the ground wire, so that the energy storage battery can limit the current at the deterioration failure position in the case of insulation failure, prevent the insulation material at the deterioration position of the energy storage battery from being thermally damaged, limit the further deterioration trend of the insulation material, and avoid the thermal runaway problem caused by severe discharge, thereby improving the safety of the energy storage battery.

[0059] In some embodiments, the insulation protection method further comprises:

[0060] sampling the current flowing through the current limiting module to obtain a ground wire sampling current;

[0061] determining the insulation protection state of the energy storage battery according to the ground wire sampling current.

[0062] In the technical solution of the embodiments of the present application, the current sampling module can sample the current flowing through the current limiting module to obtain a ground wire sampling current, and the master control module can determine the insulation protection state of the energy storage battery according to the ground wire sampling current. If the energy storage battery has insulation failure, the current flowing through the current limiting module will increase. Therefore, by judging the sampled current sampling signal, the purpose of monitoring the insulation protection state of the energy storage battery can be achieved.

[0063] In some embodiments, the insulation protection method further comprises:

[0064] detecting an internal equivalent insulation resistance of the energy storage battery;

[0065] determining the insulation protection state of the energy storage battery according to the internal equivalent insulation resistance of the energy storage battery.

[0066] In the technical solution of the embodiments of the present application, the insulation detection module detects the internal equivalent insulation resistance of the energy storage battery, and the master control module determines the insulation protection state of the energy storage battery according to the internal equivalent insulation resistance of the energy storage battery. When the energy storage battery has insulation failure, the internal equivalent insulation resistance of the energy storage battery will decrease due to the insulation failure of the energy storage battery. Therefore, the internal equivalent insulation resistance of the energy storage battery is compared with a preset threshold resistance. When the internal equivalent insulation resistance of the energy storage battery is lower than the preset threshold resistance, it can be determined that the energy storage battery has insulation failure.

[0067] In some embodiments, detecting the internal equivalent insulation resistance of the energy storage battery comprises:

[0068] controlling the working state of a first insulation detection unit between the positive electrode of the energy storage battery and the ground wire and a second insulation detection unit between the negative electrode of the energy storage battery and the ground wire;

[0069] determining the internal equivalent insulation resistance of the energy storage battery according to the voltage between the positive electrode of the energy storage battery and the ground wire and the voltage between the negative electrode of the energy storage battery and the ground wire.

[0070] In some embodiments, the internal equivalent insulation resistance of the energy storage battery comprises a first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and a second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire.

[0071] In the technical scheme of the embodiments of the present application, the first insulation detection unit is connected between the positive electrode of the energy storage battery and the current sampling module, and the second insulation detection unit is connected between the negative electrode of the energy storage battery and the current sampling module. By controlling the switching state of the first insulation detection unit and the second insulation detection unit, the voltage between the positive electrode of the energy storage battery and the ground wire and the voltage between the negative electrode of the energy storage battery and the ground wire can be sampled, so that the first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire can be obtained based on the sampled voltage. The internal equivalent insulation resistance of the energy storage battery comprises the first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire. The main control module determines the insulation protection state of the energy storage battery according to the internal equivalent insulation resistance of the energy storage battery. When insulation failure occurs in the energy storage battery, the internal equivalent insulation resistance of the energy storage battery will decrease due to the insulation failure of the energy storage battery. Therefore, the internal equivalent insulation resistance of the energy storage battery is compared with the preset threshold resistance. When the internal equivalent insulation resistance of the energy storage battery is lower than the preset threshold resistance, it can be determined that the energy storage battery has insulation failure.

[0072] In some embodiments, the insulation protection method further comprises:

[0073] detecting the internal equivalent insulation resistance of the energy storage battery before the high-voltage power-on of the energy storage battery, and controlling the high-voltage power-on of the energy storage battery according to the internal equivalent insulation resistance of the energy storage battery.

[0074] In the technical solution of the embodiment of the application, the inner equivalent insulation resistance of the energy storage battery includes the first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire. The inner equivalent insulation resistance of the energy storage battery includes the first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire. The inner equivalent insulation resistance of the energy storage battery is detected before power-on, and the high-voltage power-on of the energy storage battery is controlled according to the inner equivalent insulation resistance of the energy storage battery. The problem of severe discharge of the energy storage battery in the case of insulation failure can be avoided when the energy storage battery is directly powered on at high voltage, and the safety of the high-voltage power-on operation is improved.

[0075] In some embodiments, the insulation protection method further includes:

[0076] In the case where the resistance value of the inner equivalent insulation resistance of the energy storage battery is greater than the first threshold resistance, the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are detected, and in the case where the resistance value of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance is greater than the second threshold resistance, the high-voltage power-on of the energy storage battery is controlled.

[0077] In the technical solution of the embodiment of the application, if the resistance value of the inner equivalent insulation resistance of the energy storage battery is greater than the first threshold resistance, it indicates that the inner equivalent insulation resistance of the energy storage battery is within the safe resistance value range. In order to further detect the outer equivalent insulation resistance of the energy storage battery, the positive bus side equivalent insulation resistance can be detected by turning on the main positive relay and turning off the main negative relay, and the negative bus side equivalent insulation resistance can be detected by turning on the main negative relay and turning off the main positive relay. If the resistance value of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance is greater than the second threshold resistance, it indicates that the equivalent insulation resistance between the positive or negative DC bus and the shell of the electric cabinet corresponding to the energy storage battery is within the safe threshold range, and the equivalent insulation resistance between the load positive or negative bus and the electric platform of the energy storage power station corresponding to the energy storage battery is within the safe threshold range. The energy storage battery can normally execute the high-voltage power-on process.

[0078] In some embodiments, the insulation protection method further includes:

[0079] In the case where the resistance value of the inner equivalent insulation resistance of the energy storage battery is equal to or less than the first threshold resistance, a first alarm signal is generated.

[0080] In the technical solution of the embodiment of the application, if the resistance value of the inner equivalent insulation resistance of the energy storage battery is equal to or less than the first threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus and the shell between the positive electrode of the energy storage battery and the main positive relay is out of the safety threshold range, and there is a risk of insulation failure, and the first alarm signal is generated by the main control module to remind the user to detect the energy storage battery.

[0081] In some embodiments, the insulation protection method further comprises:

[0082] The positive bus side equivalent insulation resistance after the main positive relay is turned on and the main negative relay is turned off is detected, and the insulation protection state of the energy storage battery is determined according to the resistance value of the positive bus side equivalent insulation resistance.

[0083] In the technical solution of the embodiment of the application, under the condition that the main positive relay is turned on and the main negative relay is turned off, there is a first power station equivalent insulation resistance between the positive DC bus and the electrical platform of the energy storage power station, the first power station equivalent insulation resistance is equivalent in parallel with the first equivalent insulation resistance, and the parallel equivalent resistance is the positive bus side equivalent insulation resistance. The main control module can determine the insulation protection state of the energy storage battery according to the resistance value of the positive bus side equivalent insulation resistance, for example, the main control module judges whether the positive bus side equivalent insulation resistance and / or the second equivalent insulation resistance under the condition that the main positive relay is turned on and the main negative relay is turned off exceeds the corresponding threshold range, if it does not exceed the corresponding threshold range, it indicates that the equivalent insulation resistance between the shell of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding DC bus is within the safety threshold range.

[0084] In some embodiments, the insulation protection method further comprises:

[0085] The second alarm signal is generated in the case that the resistance value of the positive bus side equivalent insulation resistance after the main positive relay is closed is equal to or less than the second threshold resistance.

[0086] In the technical solution of the embodiment of the application, under the condition that the main positive relay is turned on and the main negative relay is turned off, if the resistance value of the positive bus side equivalent insulation resistance is equal to or less than the second threshold resistance, it indicates that the equivalent insulation resistance between the shell of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding DC bus may exceed the safety threshold range, and the second alarm signal is generated by the main control module to remind the user to detect the shell of the energy storage battery, the energy storage cabinet and the energy storage power station.

[0087] In some embodiments, the insulation protection method further comprises:

[0088] The negative bus side equivalent insulation resistance after the main negative relay is turned on and the main positive relay is turned off is detected, and the main negative relay is controlled to be closed in the case that the resistance value of the negative bus side equivalent insulation resistance is greater than the second threshold resistance.

[0089] In the technical solution of the embodiment of the application, in the case that the main negative relay is turned on and the main positive relay is turned off, there is a second power station equivalent insulation resistance between the negative direct current bus and the electric platform of the energy storage power station, the second power station equivalent insulation resistance is equivalent in parallel with the second equivalent insulation resistance, and the equivalent resistance after parallel connection is the equivalent insulation resistance on the negative bus side. The main control module can determine the insulation protection state of the energy storage battery according to the resistance value of the equivalent insulation resistance on the negative bus side. For example, the main control module determines whether the equivalent insulation resistance on the negative bus side and / or the first equivalent insulation resistance in the case that the main positive relay is turned off and the main negative relay is turned on exceeds the corresponding threshold range. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistance between the housing of the energy storage battery, the energy storage cabinet and the energy storage power station and the corresponding direct current bus is within the safety threshold range.

[0090] In some embodiments, the insulation protection method further comprises:

[0091] detecting the inside equivalent insulation resistance of the energy storage battery in the single-point insulation failure state;

[0092] locating the position of the single-point insulation failure of the energy storage battery according to the inside equivalent insulation resistance of the energy storage battery in the single-point insulation failure state.

[0093] In the technical solution of the embodiment of the application, when the energy storage battery has single-point insulation failure or appears a deteriorated working condition, the inside equivalent insulation resistance of the energy storage battery in the single-point insulation failure state is detected, and the position of the single-point insulation failure of the energy storage battery is located according to the inside equivalent insulation resistance of the energy storage battery in the single-point insulation failure state, so as to timely remind the user of the insulation failure position, thereby improving the fault elimination efficiency of the energy storage battery.

[0094] In some embodiments, the insulation protection method further comprises:

[0095] In the case that the first insulation detection unit and the second insulation detection unit are in the turned-on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a second sampling voltage;

[0096] In the case that the first sampling voltage is less than the second sampling voltage, the first insulation detection unit is controlled to be in the turned-on state, the second insulation detection unit is controlled to be in the turned-off state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a third sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a fourth sampling voltage;

[0097] The inner equivalent insulation resistance of the energy storage battery is calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground sampling current.

[0098] In the technical solution of the embodiment, the first insulation detection unit is equivalent to be connected in parallel with the first equivalent insulation resistance, and the second insulation detection unit is equivalent to be connected in parallel with the second equivalent insulation resistance. In the first sampling stage, the first insulation detection unit and the second insulation detection unit are controlled to be in the conducting state, the voltage between the positive electrode of the energy storage battery and the ground is sampled to obtain the first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground is sampled to obtain the second sampling voltage. In the second sampling stage, if the first sampling voltage is less than the second sampling voltage, the first insulation detection unit is controlled to be in the conducting state, the second insulation detection unit is controlled to be in the off state, the voltage between the positive electrode of the energy storage battery and the ground is sampled to obtain the third sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground is sampled to obtain the fourth sampling voltage. In this way, the inner equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground sampling current, the accuracy of the inner equivalent insulation resistance of the energy storage battery can be improved, and whether the energy storage battery is in the insulation failure state can be determined based on the inner equivalent insulation resistance.

[0099] In some embodiments, the insulation protection method further includes:

[0100] In the case that the first sampling voltage is greater than or equal to the second sampling voltage, the first insulation detection unit is controlled to be in the off state, the second insulation detection unit is controlled to be in the conducting state, the voltage between the positive electrode of the energy storage battery and the ground is sampled to obtain the fifth sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground is sampled to obtain the sixth sampling voltage.

[0101] The inner equivalent insulation resistance of the energy storage battery is calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground sampling current.

[0102] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the first sampling stage, the first insulation detection unit and the second insulation detection unit are controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a second sampling voltage. In the second sampling stage, if the first sampling voltage is greater than or equal to the second sampling voltage, the first insulation detection unit is controlled to be in the off state, the second insulation detection unit is controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a fifth sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a sixth sampling voltage. In this way, the inner equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current, the accuracy of the inner equivalent insulation resistance of the energy storage battery can be improved, and whether the energy storage battery has insulation failure can be determined based on the inner equivalent insulation resistance.

[0103] In some embodiments, the insulation protection method further includes:

[0104] The single-point insulation failure position of the energy storage battery is determined according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground wire sampling current.

[0105] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the first sampling stage, the first insulation detection unit and the second insulation detection unit are controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a second sampling voltage. In the second sampling stage, if the first sampling voltage is greater than or equal to the second sampling voltage, the first insulation detection unit is controlled to be in the off state, the second insulation detection unit is controlled to be in the on state, the voltage between the positive electrode of the energy storage battery and the ground wire is sampled to obtain a fifth sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a sixth sampling voltage. In this way, the inner equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current, the accuracy of the inner equivalent insulation resistance of the energy storage battery can be improved, and whether the energy storage battery has insulation failure can be determined based on the inner equivalent insulation resistance.

[0106] In some embodiments, the insulation protection method further includes:

[0107] The single-point insulation failure position of the energy storage battery is determined according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current.

[0108] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the case that the first sampling voltage is greater than or equal to the second sampling voltage, the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery and the single-point insulation failure position can be calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current. Therefore, the specific single-point insulation failure position can be determined through the first voltage and the second voltage, and the efficiency of troubleshooting of the energy storage battery is improved.

[0109] In some embodiments, the insulation protection method further comprises:

[0110] The insulation deterioration degree of the energy storage battery is determined according to the inside equivalent insulation resistance of the energy storage battery.

[0111] In the technical solution of the embodiment of the application, the first insulation detection unit is equivalent to the first equivalent insulation resistor in parallel connection, and the second insulation detection unit is equivalent to the second equivalent insulation resistor in parallel connection. In the case that the first sampling voltage is greater than or equal to the second sampling voltage, the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery and the single-point insulation failure position can be calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground wire sampling current. Therefore, the specific single-point insulation failure position can be determined through the first voltage and the second voltage, and the efficiency of troubleshooting of the energy storage battery is improved.

[0112] The third aspect of the embodiment of the application provides an energy storage system, which comprises an energy storage battery and an insulation protection circuit according to any one of the above embodiments.

[0113] The fourth aspect of the embodiment of the application provides an energy storage system, which comprises an energy storage battery, a current limiting module and a master control module. The energy storage battery comprises a plurality of battery assemblies connected in series. The shell of the battery assembly is grounded through the current limiting module. The master control module is used to execute the insulation protection method according to any one of the above embodiments.

[0114] In the technical scheme of the embodiment of the present application, the shells of the plurality of battery assemblies are grounded through the current limiting module. When insulation failure occurs in the shell of any one of the battery assemblies, the current limiting module can limit the current of the loop formed by the battery assembly and the ground wire. In addition, the shells of the plurality of battery assemblies are connected to each other through the current limiting module. When double-point insulation failure occurs in the energy storage battery, the current limiting module can limit the current flowing therethrough. In this way, the energy storage battery can limit the current at the deterioration failure position when insulation failure occurs, prevent the deterioration position of the energy storage battery from being damaged by heat of the insulation material, limit the further deterioration trend of the insulation material, avoid thermal runaway caused by severe discharge, and improve the safety of the energy storage battery.

[0115] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, the above and other purposes, characteristics and advantages of the present application can be implemented according to the content of the specification. The following specific embodiments of the present application are described. Advantages

[0116] In the technical scheme of the embodiment of the present application, the shells of the plurality of battery assemblies are grounded through the current limiting module. When insulation failure occurs in the shell of any one of the battery assemblies, the current limiting module can limit the current of the loop formed by the battery assembly and the ground wire. In addition, the shells of the plurality of battery assemblies are connected to each other through the current limiting module. When double-point insulation failure occurs in the energy storage battery, the current limiting module can limit the current flowing therethrough. In this way, the energy storage battery can limit the current at the deterioration failure position when insulation failure occurs, prevent the deterioration position of the energy storage battery from being damaged by heat of the insulation material, limit the further deterioration trend of the insulation material, avoid thermal runaway caused by severe discharge, and improve the safety of the energy storage battery. BRIEF DESCRIPTION OF DRAWINGS

[0117] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings refer to the same or like components throughout the several drawings. In the drawings:

[0118] FIG. 1 is a first structure schematic diagram of an insulation protection circuit according to an embodiment of the present application;

[0119] FIG. 2 is a second structure schematic diagram of an insulation protection circuit according to an embodiment of the present application;

[0120] FIG. 3 is a third structure schematic diagram of an insulation protection circuit according to an embodiment of the present application;

[0121] Fig. 4 is a fourth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0122] Fig. 5 is a fifth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0123] Fig. 6 is a sixth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0124] Fig. 7 is a seventh structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0125] Fig. 8 is an eighth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0126] Fig. 9 is a ninth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0127] Fig. 10 is a tenth structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0128] Fig. 11 is an eleventh structural schematic diagram of the insulation protection circuit according to an embodiment of the present application;

[0129] Fig. 12 is a first flowchart of a method for insulation protection according to an embodiment of the present application;

[0130] Fig. 13 is a second flowchart of a method for insulation protection according to an embodiment of the present application;

[0131] Fig. 14 is a third flowchart of a method for insulation protection according to an embodiment of the present application;

[0132] Fig. 15 is a fourth flowchart of a method for insulation protection according to an embodiment of the present application;

[0133] Fig. 16 is a fifth flowchart of a method for insulation protection according to an embodiment of the present application;

[0134] Fig. 17 is a sixth flowchart of a method for insulation protection according to an embodiment of the present application;

[0135] Fig. 18 is a seventh flowchart of a method for insulation protection according to an embodiment of the present application;

[0136] Fig. 19 is an eighth flowchart of a method for insulation protection according to an embodiment of the present application;

[0137] Fig. 20 is a ninth flowchart of a method for insulation protection according to an embodiment of the present application;

[0138] Fig. 21 is a tenth flowchart of a method for insulation protection according to an embodiment of the present application;

[0139] FIG. 22 is a flowchart of a method for insulation protection according to an embodiment of the present application;

[0140] FIG. 23 is a flowchart of a method for insulation protection according to an embodiment of the present application;

[0141] FIG. 24 is a flowchart of a method for insulation protection according to an embodiment of the present application;

[0142] FIG. 25 is a flowchart of a method for insulation protection according to an embodiment of the present application;

[0143] FIG. 26 is a flowchart of a method for insulation protection according to an embodiment of the present application. Embodiments of the present application

[0144] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0145] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising" and "having," and any variations thereof, as used herein are intended to cover a non-exclusive inclusion.

[0146] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0147] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase is not necessarily used to refer to the same embodiment, nor is it necessarily used to refer to a preferred or alternative embodiment. It is explicitly and implicitly understood by those skilled in the art that an embodiment described herein can be combined with another embodiment.

[0148] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0149] In the description of the embodiments of the present application, the term "multi-frame" refers to two or more (including two).

[0150] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0151] In the related art, the balanced bridge insulation detection method is widely used in battery system insulation detection due to its simple structure and easy implementation. However, in the single-point insulation abnormal working condition, the balanced bridge insulation detection method has problems such as inaccurate measurement of the actual insulation resistance of the system, inability to locate the insulation abnormal position, and unknown insulation degradation degree. In the double-point insulation abnormal working condition, the balanced bridge insulation detection scheme cannot realize double-point failure protection, which will cause the battery to discharge violently, and further cause thermal runaway.

[0152] To solve the above technical problems, the embodiments of the present application provide an insulation protection circuit for insulating protection of an energy storage battery. As shown in FIG. 1, the energy storage battery 100 includes a plurality of battery assemblies 110 connected in series, and the insulation protection circuit includes a current limiting module 200 connected with the housings of the plurality of battery assemblies 110, and the housings of the plurality of battery assemblies 110 are grounded through the current limiting module 200.

[0153] In the embodiment, the plurality of battery assemblies 110 are connected in series, the positive electrode of the first battery assembly 110 is connected to the positive DC bus 101 as the positive electrode of the energy storage battery 100, the positive electrodes of the other battery assemblies 110 are connected to the negative electrode of the previous battery assembly 110, and the negative electrode of the last battery assembly 110 can be connected to the negative DC bus 102 as the negative electrode of the energy storage battery 100. When the insulation of the shell of any one of the battery assemblies 110 fails, the shell of the battery assembly 110 is short-circuited with the positive electrode or the negative electrode of the battery assembly 110, so that the battery assembly 110 with the failed shell insulation discharges. In the embodiment, the shells of the plurality of battery assemblies 110 are connected to the ground through the current limiting module 200. When the shell of any one of the battery assemblies 110 fails, the current limiting module 200 can limit the current of the loop formed by the battery assembly 110 and the ground, so that the energy storage battery 100 limits the current at the position of the deterioration failure in the case of insulation failure, prevents the insulation material at the deterioration position of the energy storage battery 100 from being thermally damaged, limits the further deterioration trend of the insulation material, avoids the thermal runaway problem caused by the severe discharge of the energy storage battery 100, and improves the safety of the energy storage battery 100.

[0154] In some embodiments, the shells of the battery assemblies 110 are connected to each other through the current limiting module 200.

[0155] In the embodiment, the plurality of battery assemblies 110 in the energy storage battery 100 are connected in series. When the energy storage battery 100 has double-point insulation failure, some of the battery assemblies 110 form a discharge loop. Taking the case that the negative electrode of the nth battery assembly 110 is short-circuited to the shell and the positive electrode of the first battery assembly 110 is short-circuited to the shell as an example, other cases are similar. At this time, the current flows out from the positive electrode of the (n-1)th battery assembly 110, passes through the shell of the (n-1)th battery assembly 110 and the corresponding current limiting resistor, reaches the corresponding current limiting resistor of the 2nd battery assembly 110 and the shell thereof, and then enters the negative electrode of the 2nd battery assembly 110 to form a loop. Therefore, by connecting the shells of the battery assemblies 110 to each other through the current limiting module 200, the current limiting module 200 can limit the current in the case of double-point insulation failure of the energy storage battery 100, so as to solve the thermal runaway problem caused by severe discharge in the case of double-point insulation failure of the battery, and improve the safety of the system.

[0156] In some embodiments, the positive electrode or the negative electrode of any two battery assemblies 110 in the energy storage battery 100 is short-circuited to the shell, which can represent the working condition of double-point insulation failure of the energy storage battery 100.

[0157] In some embodiments, the positive electrode or the negative electrode in any one of the battery assemblies 110 in the energy storage battery 100 is short-circuited with the outer shell thereof, which indicates that the energy storage battery 100 is in a working condition of double-point insulation failure.

[0158] In some embodiments, as shown in FIG. 2, the insulation protection circuit further comprises a current sampling module 300 and a master control module 400. The current sampling module 300 is connected in series with the current limiting module 200, and is configured to sample the current flowing through the current limiting module 200 to obtain a ground line sampling current. The master control module 400 is connected with the current sampling module 300, and is configured to determine the insulation protection state of the energy storage battery 100 according to the ground line sampling current.

[0159] In the present embodiment, the current flowing through the current limiting module 200 is sampled by the current sampling module 300 to obtain a ground line sampling current, and the master control module 400 determines the insulation protection state of the energy storage battery 100 according to the ground line sampling current. If the energy storage battery 100 has an insulation failure problem, the current flowing through the current limiting module 200 increases. Thus, the purpose of monitoring the insulation protection state of the energy storage battery 100 can be achieved by judging the sampled current sampling signal.

[0160] In some embodiments, the current limiting module 200 can be connected with the ground line through the current sampling module 300.

[0161] In some embodiments, the ground line sampling current can be obtained by the ratio of the voltage value across the sampling resistor in the current sampling module 300 to the resistance value of the sampling resistor, for example, the ground line sampling current Is = Us / Rs, wherein Us is the voltage value across the sampling resistor Rs in the current sampling module 300, and Rs is the resistance value of the sampling resistor Rs in the current sampling module 300.

[0162] In some embodiments, the ground line sampling current can also be obtained by the ratio of the voltage value across the current limiting module 200 to the resistance value of the current limiting module 200, for example, the ground line sampling current Is = U0 / R0, wherein U0 is the voltage value across the current limiting module 200, and R0 is the resistance value of the current limiting module 200 between the insulation failure position of the energy storage battery 100 and the current sampling module 300.

[0163] In some embodiments, the ground line sampling current Is = U0 / (Rs+R0), wherein U0 is the voltage value across the circuit composed of the current sampling module 300 and the current limiting module 200, Rs is the resistance value of the sampling resistor Rs in the current sampling module 300, and R0 is the resistance value of the current limiting module 200 between the insulation failure position of the energy storage battery 100 and the current sampling module 300.

[0164] In some embodiments, as shown in FIG. 3, the current limiting module 200 includes one resistor unit 210, and the shells of the plurality of battery assemblies 110 are connected to the current sampling module 300 through the corresponding resistor unit 210.

[0165] In the embodiment, the shells of the plurality of battery assemblies 110 can be connected to the same resistor unit 210, and the ground wire is connected through the resistor unit 210. In this way, it is not necessary to separately set the current limiting resistor for each battery assembly 110.

[0166] In some embodiments, as shown in FIG. 3, in specific applications, the shells of the plurality of battery assemblies 110 can be connected to the same resistor unit 210, and the ground wire is connected through the resistor unit 210. In this way, the single-point insulation abnormal positioning of the energy storage battery 100 and the monitoring of the internal equivalent insulation resistance of the energy storage battery 100 can still be retained.

[0167] In some embodiments, as shown in FIG. 4, the current limiting module 200 includes a plurality of resistor units 210, and the shells of the plurality of battery assemblies 110 are connected to the current sampling module 300 through the corresponding resistor unit 210.

[0168] In the embodiment, the current sampling module 300 samples the current flowing through the current limiting module 200 to obtain a ground wire sampling current, and the master control module 400 determines the insulation protection state of the energy storage battery 100 according to the ground wire sampling current. If the energy storage battery 100 has insulation failure problems, the current flowing through the current limiting module 200 increases. In this way, the purpose of monitoring the insulation protection state of the energy storage battery 100 can be achieved by judging the sampled current sampling signal.

[0169] In some embodiments, the number of battery assemblies 110 in the energy storage battery 100 is the same as the number of resistor units 210 in the current limiting module 200, and the plurality of resistor units 210 are connected to the plurality of battery assemblies 110 in correspondence, and each battery assembly 110 is connected to one end of the current sampling module 300 through the corresponding resistor unit 210. In this way, the single-point insulation failure or multi-point insulation failure of the battery assembly 100 in the energy storage battery 100 can be processed by the current limiting module 200 to limit the current in the loop, which can solve the problem of thermal runaway caused by the severe discharge of the energy storage battery 100 in the insulation failure condition, and improve the deterioration trend of the insulation failure, thereby improving the safety of the system.

[0170] In some embodiments, the number of battery assemblies 110 in the energy storage battery 100 can be n, and the number of resistance units 210 in the current limiting module 200 can be n-1. In this way, when there are double-point insulation failures in the battery assemblies 110 in the energy storage battery 100, the formed loop must pass through at least one resistance unit 210, and the current in the loop is limited by the resistance unit 210, which can solve the problem of thermal runaway caused by severe discharge of the energy storage battery 100 in the case of double-point insulation failure, improve the deterioration trend of insulation failure, and improve the safety of the system.

[0171] In some embodiments, as shown in FIG. 5, when the energy storage battery 100 includes n battery assemblies 110 and the current limiting module 200 includes n-1 resistance units 210, at least one resistance unit 210 is arranged between adjacent battery assemblies 110. In this design, when there are double-point insulation failures in the battery assemblies 110 in the energy storage battery 100, the formed loop must pass through at least one resistance unit 210, and the current in the loop is limited by the resistance unit 210, which can solve the problem of thermal runaway caused by severe discharge of the energy storage battery 100 in the case of double-point insulation failure, improve the deterioration trend of insulation failure, and improve the safety of the system.

[0172] In some embodiments, the current sampling module 300 can be connected to a preset sampling node, which is directly electrically connected to the shell of the battery assembly 110 at a preset position in the energy storage battery 100. When there is a single-point insulation failure in the battery assembly 110 in the energy storage battery 100, any battery assembly 110 with a single-point insulation failure forms a current loop with the current sampling module 300, and the ground sampling current is obtained by sampling the current in the current loop by the current sampling module 300. The main control module 400 is connected to the current sampling module 300, and the main control module 400 is used to determine the insulation protection state of the energy storage battery 100 according to the ground sampling current.

[0173] In some embodiments, at least one resistance unit 210 can be arranged in the current loop formed by any battery assembly 110 with a single-point insulation failure and the current sampling module 300, and the resistance unit 210 can be arranged between the battery assembly 110 and the current sampling module 300.

[0174] In this embodiment, if the energy storage battery 100 has an insulation failure problem, the current flowing through the resistance unit 210 increases, so that the purpose of monitoring the insulation protection state of the energy storage battery 100 can be achieved by judging the sampled current sampling signal.

[0175] In some embodiments, the resistance unit 210 can include one or more current limiting resistors, and the resistance unit 210 has a large resistance value and can limit the current in the loop.

[0176] In some embodiments, as shown in FIG. 6, the insulation protection circuit further comprises an insulation detection module 500 connected to the positive electrode of the energy storage battery 100, the negative electrode of the energy storage battery 100, and the ground wire, and the insulation detection module 500 is controlled by the master control module 400, and is used to detect the inner equivalent insulation resistance of the energy storage battery 100. The master control module 400 determines the insulation protection state of the energy storage battery 100 according to the inner equivalent insulation resistance of the energy storage battery 100.

[0177] In this embodiment, the inner equivalent insulation resistance of the energy storage battery 100 is detected by the insulation detection module 500, and the master control module 400 determines the insulation protection state of the energy storage battery 100 according to the inner equivalent insulation resistance of the energy storage battery 100. When the insulation failure of the energy storage battery 100 occurs, the inner equivalent insulation resistance of the energy storage battery 100 will decrease due to the insulation failure of the energy storage battery 100, so the inner equivalent insulation resistance of the energy storage battery 100 is compared with the preset threshold resistance, and when the inner equivalent insulation resistance of the energy storage battery 100 is lower than the preset threshold resistance, it can be determined that the insulation failure of the energy storage battery 100 occurs.

[0178] In some embodiments, as shown in FIG. 7, the insulation detection module 500 comprises a first insulation detection unit 510 and a second insulation detection unit 520, the first insulation detection unit 510 is connected between the positive electrode of the energy storage battery 100 and the current sampling module 300, and the second insulation detection unit 520 is connected between the negative electrode of the energy storage battery 100 and the current sampling module 300.

[0179] In this embodiment, the first insulation detection unit 510 is connected between the positive electrode of the energy storage battery 100 and the current sampling module 300, and the second insulation detection unit 520 is connected between the negative electrode of the energy storage battery 100 and the current sampling module 300. By controlling the switching state of the first insulation detection unit 510 and the second insulation detection unit 520, the voltage between the positive electrode of the energy storage battery 100 and the ground wire and the voltage between the negative electrode of the energy storage battery 100 and the ground wire can be sampled, so that the first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground wire can be obtained based on the sampling voltage. The master control module 400 determines the insulation protection state of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery 100. When the insulation failure of the energy storage battery 100 occurs, the inner equivalent insulation resistance of the energy storage battery 100 will decrease due to the insulation failure of the energy storage battery 100, so the inner equivalent insulation resistance of the energy storage battery 100 is compared with the preset threshold resistance, and when the inner equivalent insulation resistance of the energy storage battery 100 is lower than the preset threshold resistance, it can be determined that the insulation failure of the energy storage battery 100 occurs.

[0180] In some embodiments, the inner side equivalent insulation resistance of the energy storage battery 100 includes a first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground wire and a second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground wire. The master control module 400 can compare the first equivalent insulation resistance or the second equivalent insulation resistance with a preset threshold resistance, and when at least one of the first equivalent insulation resistance and the second equivalent insulation resistance is lower than the preset threshold resistance, it can be determined that the energy storage battery has insulation failure.

[0181] In some embodiments, as shown in FIG. 8, the first insulation detection unit 510 includes a first switch K1 and a first resistor, and the first switch K1 and the first resistor are connected in series between the positive electrode of the energy storage battery 100 and the current sampling module 300.

[0182] In some embodiments, the first resistor can include at least one of a resistor R11 and a resistor R12, and the resistor R11 and the resistor R12 are connected in series with the first switch K1.

[0183] In some embodiments, as shown in FIG. 8, the second insulation detection unit 520 includes a second switch K3 and a second resistor, and the second switch K2 and the second resistor are connected in series between the negative electrode of the energy storage battery 100 and the current sampling module 300.

[0184] In some embodiments, the second resistor can include at least one of a resistor R21 and a resistor R22, and the resistor R21 and the resistor R22 are connected in series with the second switch K2.

[0185] In some embodiments, the working states of the first insulation detection unit 510 and the second insulation detection unit 520 are controlled by the master control module 400.

[0186] In the embodiment, the first switch K1 is connected in series with the first resistor, the second switch K2 is connected in series with the second resistor, and the circuit connected in series with the first resistor and the first switch K2 is connected in parallel with the equivalent circuit between the electric cabinet shell where the energy storage battery 100 is located and the positive DC bus 101, and the circuit connected in series with the second resistor and the second switch K2 is connected in parallel with the equivalent circuit between the electric cabinet shell where the energy storage battery 100 is located and the negative DC bus 102. The positive electrode of the energy storage battery 100 is connected with the positive DC bus 101, and the negative electrode of the energy storage battery 100 is connected with the negative DC bus 102. By controlling the switching state of the first switch K1 and the second switch K2 through the master control module 400, the first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground wire can be obtained. By comparing the first equivalent insulation resistance and the second equivalent insulation resistance of the energy storage battery 100 with the preset threshold resistance, when the internal equivalent insulation resistance of the energy storage battery 100 is lower than the preset threshold resistance, it can be determined that the energy storage battery 100 has insulation failure.

[0187] In some embodiments, the master control module 400 is further configured to detect the internal equivalent insulation resistance of the energy storage battery 100 before high-voltage power-on of the energy storage battery 100, and control the high-voltage power-on of the energy storage battery 100 according to the internal equivalent insulation resistance of the energy storage battery 100.

[0188] In the embodiment, the internal equivalent insulation resistance of the energy storage battery 100 includes the first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground wire and the second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground wire. Detecting the internal equivalent insulation resistance of the energy storage battery 100 before power-on and controlling the high-voltage power-on of the energy storage battery 100 according to the internal equivalent insulation resistance of the energy storage battery 100 can avoid the problem of violent discharge of the energy storage battery 100 directly high-voltage power-on in the presence of insulation failure, and improve the safety of high-voltage power-on operation.

[0189] In some embodiments, as shown in FIG. 9, the main positive relay KM is connected between the positive DC bus 101 and the load positive bus 103, and the main negative relay KN is connected between the negative DC bus 102 and the load negative bus 104. The main positive relay KM and the main negative relay KN need to be controlled to be turned on when the high-voltage of the energy storage battery 100 is powered on. Before the high-voltage power-on process of the energy storage battery 100, the first equivalent insulation resistance Rp1 between the positive electrode of the energy storage battery 100 and the ground wire and the second equivalent insulation resistance Rn1 between the negative electrode of the energy storage battery 100 and the ground wire are detected. When the resistance values of the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 are both greater than a first threshold resistance, it indicates that the equivalent insulation resistance between the shell of the electric cabinet corresponding to the energy storage battery 100 and the positive DC bus 101 and the equivalent insulation resistance between the shell of the electric cabinet corresponding to the energy storage battery 100 and the negative DC bus 102 are both within a safe range. The high-voltage power-on detection operation before the high-voltage power-on process can be performed. In the high-voltage power-on detection operation before the high-voltage power-on process, the main positive relay KM and the main negative relay KN can be turned on in sequence.

[0190] In some embodiments, the main control module 400 is further configured to detect the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance when the internal side equivalent insulation resistance of the energy storage battery 100 has a resistance value greater than the first threshold resistance, and control the high-voltage power-on of the energy storage battery 100 when the resistance values of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than a second threshold resistance.

[0191] In the present embodiment, when the internal side equivalent insulation resistance of the energy storage battery 100 has a resistance value greater than the first threshold resistance, it indicates that the internal side equivalent insulation resistance of the energy storage battery 100 is within a safe resistance value range. In order to further detect the external side equivalent insulation resistance of the energy storage battery 100, the positive bus side equivalent insulation resistance can be detected by turning on the main positive relay KM and turning off the main negative relay KN, and the negative bus side equivalent insulation resistance can be detected by turning on the main negative relay KN and turning off the main positive relay KM. When the resistance values of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than the second threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus or the negative DC bus and the shell of the electric cabinet corresponding to the energy storage battery 100 is within a safe threshold range, and the equivalent insulation resistance between the positive DC bus 101 or the negative DC bus 102 and the electric platform of the energy storage power station corresponding to the energy storage battery 100 is within a safe threshold range. The energy storage battery 100 can normally perform the high-voltage power-on process.

[0192] In some embodiments, as shown in FIG. 9, the load positive bus 103 and the load negative bus 104 are connected to the load 610 through the energy storage power station corresponding to the energy storage battery 100. When the main positive relay KM is turned on, there is a first power station equivalent insulation resistance Rp2 between the load positive bus 103 and the electrical platform of the energy storage power station. When the main negative relay KN is turned on, there is a second power station equivalent insulation resistance Rn2 between the load negative bus 104 and the electrical platform of the energy storage power station. When the main positive relay KM is turned on, the first power station equivalent insulation resistance Rp2 and the first equivalent insulation resistance Rp1 are connected in parallel to form a positive bus side equivalent insulation resistance. When the main negative relay KN is turned on, the second power station equivalent insulation resistance Rn2 and the second equivalent insulation resistance Rn1 are connected in parallel to form a negative bus side equivalent insulation resistance. If the resistance values of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than the second threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus 101 or the negative DC bus 102 and the shell of the electrical cabinet corresponding to the energy storage battery 100 is within the safety threshold range, the equivalent insulation resistance between the positive DC bus 101 or the negative DC bus 102 and the electrical platform of the energy storage power station corresponding to the energy storage battery 100 is within the safety threshold range, and the energy storage battery can normally perform the high-voltage power-on process.

[0193] In some embodiments, the main control module 400 is further configured to generate a first alarm signal when the resistance value of the internal equivalent insulation resistance of the energy storage battery 100 is equal to or less than the first threshold resistance.

[0194] In this embodiment, if the resistance value of the internal equivalent insulation resistance of the energy storage battery 100 is equal to or less than the first threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus 101 and the shell between the positive electrode of the energy storage battery 100 and the main positive relay KM is outside the safety threshold range, and the energy storage battery 100 has a risk of insulation failure. Therefore, the main control module 400 generates a first alarm signal to remind the user to detect the energy storage battery 100.

[0195] In some embodiments, the main control module 400 is specifically configured to detect the positive bus side equivalent insulation resistance after the main positive relay KM is turned on and the main negative relay KN is turned off, and determine the insulation protection state of the energy storage battery 100 according to the resistance value of the positive bus side equivalent insulation resistance.

[0196] In the embodiment, as shown in FIG. 9, when the main positive relay KM is turned on and the main negative relay KN is turned off, there is a first power station equivalent insulation resistance Rp2 between the load positive bus 103 and the electric platform of the energy storage power station, and when the main positive relay KM is turned on, the first power station equivalent insulation resistance Rp2 and the first equivalent insulation resistance Rp1 are connected in parallel to form a positive bus side equivalent insulation resistance. The main control module 400 can determine the insulation protection state of the energy storage battery 100 according to the resistance value of the positive bus side equivalent insulation resistance. For example, the main control module 400 determines whether the positive bus side equivalent insulation resistance exceeds the corresponding threshold range when the main positive relay KM is turned on and the main negative relay KN is turned off. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistance between the energy storage battery 100, the energy storage cabinet, the shell of the energy storage power station and the corresponding DC bus is within the safe threshold range.

[0197] In some embodiments, when the main positive relay KM is turned on and the main negative relay KN is turned off, the main control module 400 determines whether the second equivalent insulation resistance Rn1 exceeds the corresponding threshold range. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistance between the energy storage battery 100, the energy storage cabinet, the shell of the energy storage power station and the corresponding DC bus is within the safe threshold range.

[0198] In some embodiments, the shell of the energy storage cabinet and the energy storage power station can be connected to the corresponding electric platform. As understood by those skilled in the art, the electric platform can be assigned a potential, and / or the electric platform can be provided with a potential. As an example, when the electric platform is grounded, the equipment connected to the electric platform (such as the electric box shell of the battery) is generally considered to be grounded, and in this example, the electric platform is assigned a ground potential by grounding, and the equipment connected to the electric platform is provided with a ground potential by the electric platform; as another example, when the electric platform is connected to the total positive line of the electric cabinet, the electric platform can be considered to be assigned the potential of the total positive line, and if there is equipment (such as the electric cabinet cabinet body of the battery) connected to the electric platform, the equipment can be considered to be provided with the potential of the total positive line by the electric platform. As an example, the electric platform can be an equipotential object, so that the devices connected to the electric platform have an equipotential. The electric platform may, for example, be a power supply ground or a conductor connected to the power supply ground, and can also be a mounting platform of the energy storage system, etc.

[0199] In some embodiments, the main control module 400 is further configured to generate a second alarm signal when the resistance value of the positive bus side equivalent insulation resistance after the main positive relay KM is turned on is equal to or less than a second threshold resistance.

[0200] In the embodiment, when the main positive relay KM is turned on and the main negative relay KN is turned off, if the resistance of the positive bus side equivalent insulation resistance is equal to or less than the second threshold resistance, it indicates that the equivalent insulation resistance between the shell of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC bus may exceed the safety threshold range, and the second alarm signal is generated by the main control module 400 to remind the user to detect the shell of the energy storage battery 100, the energy storage cabinet and the energy storage power station.

[0201] In some embodiments, the main control module 400 is specifically used for detecting the negative bus side equivalent insulation resistance after the main negative relay KN is turned on and the main positive relay KM is turned off, and controlling the main negative relay KN to close when the resistance of the negative bus side equivalent insulation resistance is greater than the second threshold resistance.

[0202] In the embodiment, as shown in FIG. 9, when the main negative relay KN is turned on and the main positive relay KM is turned off, there is a second power station equivalent insulation resistance Rn2 between the load negative bus 104 and the electric platform of the energy storage power station, which is equivalent in parallel with the second equivalent insulation resistance Rn1, and the equivalent resistance after parallel connection is the negative bus side equivalent insulation resistance. The main control module 400 can determine the insulation protection state of the energy storage battery 100 according to the resistance of the negative bus side equivalent insulation resistance, for example, whether the negative bus side equivalent insulation resistance exceeds the corresponding threshold range when the main positive relay KM is turned off and the main negative relay KN is turned on is judged by the main control module 400, if it does not exceed the corresponding threshold range, it indicates that the equivalent insulation resistance between the shell of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC bus is within the safety threshold range.

[0203] In some embodiments, whether the first equivalent insulation resistance Rp1 exceeds the corresponding threshold range when the main positive relay KM is turned off and the main negative relay KN is turned on can be judged by the main control module 400, and if it does not exceed the corresponding threshold range, it indicates that the equivalent insulation resistance between the shell of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC bus is within the safety threshold range.

[0204] In some embodiments, the main control module 400 is also used for detecting the inner side equivalent insulation resistance of the energy storage battery 100 in the single point insulation failure state, and positioning the position of the single point insulation failure of the energy storage battery 100 according to the inner side equivalent insulation resistance of the energy storage battery 100 in the single point insulation failure state.

[0205] In the embodiment, when the positive electrode or the negative electrode of any one battery assembly 110 in the energy storage battery 100 is short-circuited with the shell, it is determined that the energy storage battery 100 has a single-point insulation failure problem. When the energy storage battery 100 has a single-point insulation failure or a deteriorated working condition, the equivalent internal insulation resistance of the energy storage battery 100 in the single-point insulation failure state can be detected, and the position of the single-point insulation failure of the energy storage battery 100 can be located according to the equivalent internal insulation resistance of the energy storage battery 100 in the single-point insulation failure state, so as to timely remind the user of the insulation failure position, and improve the fault elimination efficiency of the energy storage battery 100.

[0206] In some embodiments, the main control module 400 is specifically configured to sample the voltage between the positive electrode (the positive DC bus 101) of the energy storage battery 100 and the ground to obtain a first sampling voltage Ua1, sample the voltage between the negative electrode (the negative DC bus 102) of the energy storage battery 100 and the ground to obtain a second sampling voltage Uc1, control the first insulation detection unit 510 to be in the on state and the second insulation detection unit 520 to be in the off state when the first sampling voltage Ua1 is less than the second sampling voltage Uc1, at this time, the first switch K1 is turned on and the second switch K2 is turned off, sample the voltage between the positive electrode and the ground of the energy storage battery 100 to obtain a third sampling voltage Ua2, sample the voltage between the negative electrode and the ground of the energy storage battery 100 to obtain a fourth sampling voltage Uc2, and calculate the equivalent internal insulation resistance of the energy storage battery according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current; the equivalent internal insulation resistance of the energy storage battery 100 includes the first equivalent insulation resistance Rp1 between the positive electrode and the ground of the energy storage battery 100 and the second equivalent insulation resistance Rn1 between the negative electrode and the ground of the energy storage battery 100.

[0207] In the embodiment, the first insulation detection unit 510 is equivalent in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is equivalent in parallel with the second equivalent insulation resistance Rn1. In the first sampling stage, the first insulation detection unit 510 and the second insulation detection unit 520 are controlled to be in the on state, the voltage between the positive electrode and the ground of the energy storage battery 100 is sampled to obtain the first sampling voltage Ua1, and the voltage between the negative electrode and the ground of the energy storage battery 100 is sampled to obtain the second sampling voltage Uc1. According to the Kirchhoff's law (KIL law), the following relationship (1) can be obtained:

[0208] Wherein, R11 and R12 are the resistance values of the resistors between the two ends of the first switch K1, R21 and R22 are the resistance values of the resistors between the two ends of the second switch K2, R0 is the resistance value of the current limiting module 200, Rs is the resistance value of the sampling resistor in the current sampling module 300, and the ground sampling current in the first sampling stage is Uo1 is the voltage of the circuit composed of the current limiting module 200 and the current sampling module 300 in the first sampling stage, which can be obtained by the ground sampling current and the resistance values of the current limiting module 200 and the sampling resistor in the current sampling module 300.

[0209] In the second sampling stage, if the first sampling voltage Ua1 is less than the second sampling voltage Uc1, the first insulation detection unit 510 is in the on state, the second insulation detection unit 520 is in the off state, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain the third sampling voltage Ua2, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain the fourth sampling voltage Uc2. In this way, the internal equivalent insulation resistance of the energy storage battery 100 can be accurately calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2 and the ground sampling current, which not only improves the accuracy of the internal equivalent insulation resistance of the energy storage battery 100, but also determines whether the energy storage battery 100 has insulation failure based on the internal equivalent insulation resistance.

[0210] After obtaining the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2 and the ground sampling current, the following relationship can be obtained according to the KIL law: U c2 = U2-U a2 ; (relationship 2)

[0211] Wherein, U2 is the voltage between the positive DC bus 101 and the negative DC bus 102, and relationship 4 and relationship 5 can be obtained according to relationship 2 and relationship 3 above. In this way, based on the voltage between the positive DC bus 101 and the negative DC bus 102, the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, the resistance values of the resistors between the two ends of the first switch K1, the resistance values of the resistors between the two ends of the second switch K2, the resistance value of the current limiting module 200 and the resistance value of the sampling resistor in the current sampling module 300, the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 can be obtained.

[0212] In some embodiments, the master module 400 is further configured to control the first insulation detection unit 510 to be in an off state, control the second insulation detection unit 520 to be in an on state, and sample a voltage between the positive electrode of the energy storage battery 100 and the ground to obtain a fifth sampling voltage Ua3, sample a voltage between the negative electrode of the energy storage battery 100 and the ground to obtain a sixth sampling voltage Uc3, and calculate the inner equivalent insulation resistance of the energy storage battery 100 according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, when the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1.

[0213] In the present embodiment, as shown in FIG. 10, the first insulation detection unit 510 is equivalent in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is equivalent in parallel with the second equivalent insulation resistance Rn1. In the first sampling stage, the first insulation detection unit 510 and the second insulation detection unit 520 are controlled to be in an on state, at this time, the first switch K1 and the second switch K2 are turned on, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain the first sampling voltage Ua1, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain the second sampling voltage Uc1.

[0214] In the second sampling stage, if the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1, the first insulation detection unit 510 is controlled to be in an off state, the second insulation detection unit 520 is controlled to be in an on state, the voltage between the positive electrode (the positive DC bus 101) of the energy storage battery 100 and the ground is sampled to obtain the fifth sampling voltage Ua3, and the voltage between the negative electrode (the negative DC bus 102) of the energy storage battery and the ground is sampled to obtain the sixth sampling voltage Uc3. In this way, the inner equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, which not only improves the accuracy of the inner equivalent insulation resistance of the energy storage battery, but also determines whether the energy storage battery 100 has insulation failure based on the inner equivalent insulation resistance.

[0215] After obtaining the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, the following relationship can be obtained according to the KIL law: U a3 = U3-U c3 ; (relationship 6)

[0216] Wherein, U3 is the voltage between the positive DC bus 101 and the negative DC bus 102, according to the above relationship 6, relationship 7, relationship 8, relationship 9 can be obtained, in this way, based on the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the resistance value of the resistor between the first switch K1, the resistance value of the resistor between the second switch K2, the resistance value of the current limiting module 200, and the resistance value of the sampling resistor in the current sampling module 300, the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 can be obtained.

[0217] In some embodiments, the master module 400 is also used to determine the single-point insulation failure position of the energy storage battery according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current.

[0218] In this embodiment, the first insulation detection unit 510 is equivalent in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is equivalent in parallel with the second equivalent insulation resistance Rn1. In the case where the first sampling voltage Ua1 is less than the second sampling voltage Uc1, the first voltage Ua between the positive electrode of the energy storage battery 100 and the single-point insulation failure position, and the second voltage Uc between the negative electrode of the energy storage battery 100 and the single-point insulation failure position can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current, therefore, the specific single-point insulation failure position can be determined through the first voltage Ua and the second voltage Uc, and the efficiency of troubleshooting of the energy storage battery is improved.

[0219] In some embodiments, after obtaining the first sampling voltage Ua1, the second sampling voltage Uc1, and the ground sampling current in the first sampling stage, the following relationship can be obtained according to the KIL law:

[0220] Wherein, Uc is the second voltage between the negative electrode of the energy storage battery and the single-point insulation failure position, Ua is the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position, and Rl is the equivalent insulation degradation resistance of the energy storage battery 100.

[0221] In some embodiments, after obtaining the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current in the second sampling stage, the following relationship can be obtained according to the KIL law:

[0222] The single-point insulation failure or degradation voltage position can be calculated by relationship 13, at this time, assuming that the energy storage battery 100 is composed of N series of cells, when the nth cell fails, the following formula should be satisfied:

[0223] In the embodiment, ux is the voltage of the battery assembly 110, and n is the nth battery assembly in the energy storage battery 100.

[0224] In some embodiments, the master module 400 is further configured to determine the single-point insulation failure position of the energy storage battery according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current.

[0225] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rn1, in the case that the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1. According to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, the first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position, and the second voltage between the negative electrode of the energy storage battery 100 and the single-point insulation failure position can be calculated. Therefore, the specific single-point insulation failure position can be determined by the first voltage and the second voltage, and the efficiency of troubleshooting of the energy storage battery 100 is improved.

[0226] In some embodiments, in the second sampling stage, after obtaining the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, the following relationship can be obtained according to the KIL law:

[0227] According to the relationship 15 and the relationship 10 and the relationship 11, the following can be obtained:

[0228] The single-point insulation failure or degradation voltage position of the energy storage battery 100 can be calculated by the relationship 14 and the relationship 16.

[0229] In some embodiments, the master module 400 is further configured to calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current, and determine the insulation degradation degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery 100.

[0230] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rpl, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rnl. In the case where the first sampling voltage Ual is less than the second sampling voltage Ucl, the equivalent insulation deterioration resistance Rl of the energy storage battery 100 can be calculated according to the first sampling voltage Ual, the second sampling voltage Ucl, the third sampling voltage A2, and the fourth sampling voltage Uc2. Under normal working conditions, the charging and discharging circuit and the shell equivalent insulation resistance are above tens of megaohms due to the protection of the blue film and the insulation material of the energy storage battery 100. When insulation failure or deterioration occurs, the equivalent insulation resistance decreases, and thus the insulation deterioration severity of the energy storage battery 100 can be evaluated according to the equivalent insulation deterioration resistance Rl of the energy storage battery 100.

[0231] In some embodiments, in the case where the first sampling voltage Ual is less than the second sampling voltage Ucl, the equivalent insulation deterioration resistance Rl of the energy storage battery 100 can be calculated according to the first sampling voltage Ual, the second sampling voltage Ucl, the third sampling voltage Ua2, and the fourth sampling voltage Uc2, as shown in the following relationship 17:

[0232] In the embodiment, the equivalent insulation deterioration resistance Rl of the energy storage battery 100 can be calculated by the relationship 17, and the insulation deterioration severity of the energy storage battery 100 can be evaluated by the equivalent insulation deterioration resistance Rl of the energy storage battery 100. For example, the ratio of the equivalent insulation deterioration resistance Rl of the energy storage battery 100 to the preset equivalent insulation threshold resistance is calculated. The greater the ratio, the greater the resistance value of the equivalent insulation deterioration resistance Rl of the energy storage battery 100, and the lighter the insulation deterioration degree of the energy storage battery 100. The smaller the ratio, the smaller the resistance value of the equivalent insulation deterioration resistance Rl of the energy storage battery 100, and the more serious the insulation deterioration degree of the energy storage battery 100.

[0233] In some embodiments, the host control module 400 is further configured to calculate the equivalent insulation resistance of the energy storage battery 100 according to the first sampling voltage Ual, the second sampling voltage Ucl, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current, and determine the insulation deterioration degree of the energy storage battery 100 according to the equivalent insulation resistance of the energy storage battery 100.

[0234] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rpl, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rn1, in the case that the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1. The equivalent insulation resistance of the inside of the energy storage battery 100 can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current. Under normal working conditions, the charging and discharging circuit and the shell equivalent insulation resistance are above tens of megaohms due to the protection of the blue film and the insulation material of the energy storage battery 100. When insulation failure or degradation occurs, the equivalent insulation resistance decreases, and thus the insulation degradation severity can be evaluated according to the equivalent insulation resistance of the inside of the energy storage battery.

[0235] In some embodiments, in the case that the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1, the equivalent insulation degradation resistance Rl of the energy storage battery 100 can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, and the sixth sampling voltage Uc3, as shown in the following relationship 18:

[0236] In the embodiment, the equivalent insulation degradation resistance Rl of the energy storage battery 100 can be calculated by the relationship 18, and the insulation degradation severity of the energy storage battery 100 can be evaluated by the equivalent insulation degradation resistance Rl of the energy storage battery 100. For example, the ratio of the equivalent insulation degradation resistance Rl of the energy storage battery 100 to the preset equivalent insulation threshold resistance is calculated. The larger the ratio is, the greater the resistance value of the equivalent insulation degradation resistance Rl of the energy storage battery 100 is, and the lighter the insulation degradation degree of the energy storage battery 100 is. The smaller the ratio is, the smaller the resistance value of the equivalent insulation degradation resistance Rl of the energy storage battery 100 is, and the more serious the insulation degradation degree of the energy storage battery 100 is.

[0237] In some embodiments, when the ratio of the equivalent insulation degradation resistance Rl of the energy storage battery 100 to the preset equivalent insulation threshold resistance is equal to or less than the preset evaluation ratio, it indicates that the energy storage battery 100 has an insulation degradation risk, and the main control module 400 can generate a corresponding early warning signal to remind the user to perform insulation fault detection on the energy storage battery 100.

[0238] The embodiment of the present application provides an insulation protection method for insulating and protecting an energy storage battery. The energy storage battery includes a plurality of battery assemblies connected in series. The insulation protection method includes the step S100 of controlling the shells of the plurality of battery assemblies to be grounded through a current limiting module.

[0239] In the embodiment, in combination with FIG. 1, the plurality of battery assemblies 110 are connected in series in sequence, the positive electrode of the first battery assembly 110 is connected to the positive DC bus 101 as the positive electrode of the energy storage battery 100, the positive electrodes of the other battery assemblies 110 are connected to the negative electrode of the previous battery assembly 110, and the negative electrode of the last battery assembly 110 can be connected to the negative DC bus 102 as the negative electrode of the energy storage battery 100. When the shell of any one of the battery assemblies 110 fails in insulation, the shell of the battery assembly 110 will be short-circuited with the positive electrode or the negative electrode of the battery assembly 110, so that the battery assembly 110 with the failed shell insulation will discharge. In this step S100, the shells of the plurality of battery assemblies 110 are connected to the ground through the current limiting module 200, so that when the shell of any one of the battery assemblies 110 fails in insulation, the current limiting module 200 can limit the current of the loop formed by the battery assembly 110 and the ground, so that the energy storage battery 100 can limit the current at the position of the deterioration failure in the case of insulation failure, prevent the insulation material at the deterioration position of the energy storage battery 100 from being damaged by heat, limit the further deterioration trend of the insulation material, and avoid the thermal runaway problem caused by the severe discharge of the energy storage battery 100, thereby improving the safety of the energy storage battery 100.

[0240] In some embodiments, a corresponding switch can be arranged between the shell of the battery assembly 110 and the current limiting module 200, and the switch can be controlled by the master control module to control the connection state between the shell of the battery assembly 110 and the current limiting module 200.

[0241] In some embodiments, a corresponding switch can be arranged between the shell of the battery assembly 110 and the current limiting module 200, and the switch can be controlled by the master control module to control the connection state between the shell of the battery assembly 110 and the current limiting module 200.

[0242] In the embodiment, the plurality of battery assemblies 110 in the energy storage battery 100 are connected in series in sequence, and when the energy storage battery 100 fails in double-point insulation, some of the batteries 110 will form a discharge loop. By connecting the shells of the plurality of battery assemblies 110 to each other through the current limiting module 200, the current limiting module 200 can limit the current in the case of double-point insulation failure of the energy storage battery 100, so that the thermal runaway problem caused by the severe discharge of the battery in the case of double-point insulation failure can be solved, and the safety of the system is improved.

[0243] In some embodiments, when it is detected that the energy storage battery 100 fails in single-point insulation, the shells of the plurality of battery assemblies 110 are connected to each other through the current limiting module 200, so that the thermal runaway problem caused by the severe discharge of the energy storage battery 100 in the case of double-point insulation failure can be avoided, and the safety of the energy storage battery 100 is improved.

[0244] In some embodiments, referring to FIG. 13, the insulation protection method in the embodiment further includes steps S210 and S220.

[0245] In step S210, the current flowing through the current limiting module 200 is sampled to obtain a ground sampling current.

[0246] In step S220, the insulation protection state of the energy storage battery 100 is determined according to the ground sampling current.

[0247] In the embodiment, if the energy storage battery 100 has insulation failure problem, the current flowing through the current limiting module 200 increases, therefore, by sampling the current flowing through the current limiting module 200 to obtain the ground sampling current, the purpose of monitoring the insulation protection state of the energy storage battery 100 can be achieved based on the sampled ground sampling current.

[0248] In some embodiments, referring to FIG. 2, the current flowing through the current limiting module 200 can be sampled by the current sampling module 300 to obtain the ground sampling current, and the insulation protection state of the energy storage battery 100 can be determined by the master control module 400 according to the ground sampling current. If the energy storage battery 100 has insulation failure problem, the current flowing through the current limiting module 200 increases, therefore, by judging the sampled current sampling signal, the purpose of monitoring the insulation protection state of the energy storage battery 100 can be achieved.

[0249] In some embodiments, referring to FIG. 14, the insulation protection method in the embodiment further includes steps S310 and S320.

[0250] In step S310, the inner equivalent insulation resistance of the energy storage battery 100 is detected.

[0251] In step S320, the insulation protection state of the energy storage battery 100 is determined according to the inner equivalent insulation resistance of the energy storage battery 100.

[0252] In the embodiment, the inner equivalent insulation resistance of the energy storage battery 100 can be detected by the insulation detection module 500, and the insulation protection state of the energy storage battery 100 can be determined by the master control module 400 according to the inner equivalent insulation resistance of the energy storage battery 100. As shown in FIG. 7, the insulation detection module 500 includes a first insulation detection unit 510 and a second insulation detection unit 520. The first insulation detection unit 510 is connected between the positive electrode of the energy storage battery 100 and the current sampling module 300. The second insulation detection unit 520 is connected between the negative electrode of the energy storage battery 100 and the current sampling module 300. By controlling the switching state of the first insulation detection unit 510 and the second insulation detection unit 520, the voltage between the positive electrode of the energy storage battery 100 and the ground and the voltage between the negative electrode of the energy storage battery 100 and the ground can be sampled, so that the first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground and the second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground can be obtained based on the sampled voltage.

[0253] In the embodiment, the inner equivalent insulation resistance of the energy storage battery 100 includes the first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground and the second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground. When the insulation failure of the energy storage battery 100 occurs, the inner equivalent insulation resistance of the energy storage battery 100 will decrease due to the insulation failure of the energy storage battery 100. Therefore, the inner equivalent insulation resistance of the energy storage battery 100 is compared with the preset threshold resistance. When the inner equivalent insulation resistance of the energy storage battery 100 is lower than the preset threshold resistance, it can be determined that the insulation failure of the energy storage battery 100 occurs.

[0254] In some embodiments, in step S310, the inner equivalent insulation resistance of the energy storage battery is detected, including: controlling the working state of the first insulation detection unit between the positive electrode of the energy storage battery and the ground and the second insulation detection unit between the negative electrode of the energy storage battery and the ground; determining the inner equivalent insulation resistance of the energy storage battery according to the voltage between the positive electrode of the energy storage battery and the ground and the voltage between the negative electrode of the energy storage battery and the ground.

[0255] In the embodiment, when the first insulation detection unit 510 and the second insulation detection unit 520 are in the on state, the voltage between the positive electrode (the positive DC bus 101) of the energy storage battery 100 and the ground is sampled to obtain a first sampling voltage Ua1, and the voltage between the negative electrode (the negative DC bus 102) of the energy storage battery 100 and the ground is sampled to obtain a second sampling voltage Uc1. Further, in step S310, the voltage between the positive electrode of the energy storage battery 100 and the ground can also be sampled to obtain a third sampling voltage Ua2 when the first insulation detection unit 510 is in the on state and the second insulation detection unit 520 is in the off state, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain a fourth sampling voltage Uc2, and the internal equivalent insulation resistance of the energy storage battery is calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2, and the ground sampling current.

[0256] In some embodiments, in step S310, the first insulation detection unit 510 can also be controlled to be in the off state, the second insulation detection unit 520 can be controlled to be in the on state, and the voltage between the positive electrode of the energy storage battery 100 and the ground can be sampled to obtain a fifth sampling voltage Ua3, and the voltage between the negative electrode of the energy storage battery 100 and the ground can be sampled to obtain a sixth sampling voltage Uc3, and the internal equivalent insulation resistance of the energy storage battery 100 can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground sampling current.

[0257] In some embodiments, the internal equivalent insulation resistance of the energy storage battery 100 includes a first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground and a second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground.

[0258] In the embodiment, the internal equivalent insulation resistance of the energy storage battery 100 includes a first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground and a second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground. The first equivalent insulation resistance or the second equivalent insulation resistance can be compared with a preset threshold resistance, and when at least one of the first equivalent insulation resistance and the second equivalent insulation resistance is lower than the preset threshold resistance, it can be determined that the energy storage battery has insulation failure.

[0259] In some embodiments, referring to FIG. 15, the insulation protection method in the embodiment further includes step S400: detecting the internal equivalent insulation resistance of the energy storage battery 100 before the high-voltage power-on of the energy storage battery 100, and controlling the high-voltage power-on of the energy storage battery 100 according to the internal equivalent insulation resistance of the energy storage battery 100.

[0260] In the embodiment, the internal equivalent insulation resistance of the energy storage battery 100 includes a first equivalent insulation resistance between the positive electrode of the energy storage battery 100 and the ground wire and a second equivalent insulation resistance between the negative electrode of the energy storage battery 100 and the ground wire. The internal equivalent insulation resistance of the energy storage battery 100 is detected before power-on, and the high-voltage power-on of the energy storage battery 100 is controlled according to the internal equivalent insulation resistance of the energy storage battery 100, which can avoid the problem of severe discharge of the energy storage battery 100 in the case of insulation failure and improve the safety of the high-voltage power-on operation.

[0261] In some embodiments, referring to FIG. 16, the insulation protection method in the embodiment further includes step S500: detecting the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance in the case that the resistance value of the internal equivalent insulation resistance of the energy storage battery 100 is greater than the first threshold resistance, and controlling the high-voltage power-on of the energy storage battery 100 in the case that the resistance value of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance is greater than the second threshold resistance.

[0262] In the embodiment, as shown in FIG. 9, if the resistance value of the internal equivalent insulation resistance of the energy storage battery 100 is greater than the first threshold resistance, it indicates that the internal equivalent insulation resistance of the energy storage battery 100 is within the safe resistance value range. In order to further detect the external equivalent insulation resistance of the energy storage battery 100, the positive bus side equivalent insulation resistance can be detected by turning on the main positive relay KM and turning off the main negative relay KN, and the negative bus side equivalent insulation resistance can be detected by turning on the main negative relay KN and turning off the main positive relay KM. If the resistance value of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance is greater than the second threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus or the negative DC bus and the shell of the electric cabinet corresponding to the energy storage battery 100 is within the safe threshold range, and the equivalent insulation resistance between the positive DC bus 101 or the negative DC bus 102 and the electric platform of the energy storage power station corresponding to the energy storage battery 100 is within the safe threshold range. The energy storage battery 100 can normally execute the high-voltage power-on process.

[0263] In some embodiments, referring to FIG. 17, the insulation protection method in the embodiment further includes step S510: generating a first alarm signal in the case that the resistance value of the internal equivalent insulation resistance of the energy storage battery 100 is equal to or less than the first threshold resistance.

[0264] In the embodiment, if the equivalent insulation resistance of the inside of the energy storage battery 100 is equal to or less than the first threshold resistance, it indicates that the equivalent insulation resistance between the positive DC bus 101 and the shell between the positive electrode of the energy storage battery 100 and the main positive relay KM is out of the safety threshold range, and the energy storage battery 100 has a risk of insulation failure. The first alarm signal can be generated by the main control module 400 to remind the user to detect the energy storage battery 100.

[0265] In some embodiments, referring to FIG. 18, the insulation protection method in the embodiment further includes the step S520 of detecting the positive bus side equivalent insulation resistance after the main positive relay KM is turned on and the main negative relay KN is turned off, and determining the insulation protection state of the energy storage battery according to the resistance value of the positive bus side equivalent insulation resistance.

[0266] In the embodiment, as shown in FIG. 9, under the condition that the main positive relay is turned on and the main negative relay is turned off, there is a first power station equivalent insulation resistance Rp2 between the load positive bus 103 and the electrical platform of the energy storage power station. Under the condition that the main positive relay KM is turned on, the first power station equivalent insulation resistance Rp2 and the first equivalent insulation resistance Rp1 are connected in parallel to form the positive bus side equivalent insulation resistance. The main control module 400 can determine the insulation protection state of the energy storage battery 100 according to the resistance value of the positive bus side equivalent insulation resistance. For example, the main control module 400 determines whether the positive bus side equivalent insulation resistance under the condition that the main positive relay KM is turned on and the main negative relay KN is turned off exceeds the corresponding threshold range. If it does not exceed the corresponding threshold range, it indicates that the equivalent insulation resistances between the shells of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC buses are all within the safety threshold range.

[0267] In some embodiments, referring to FIG. 18, the insulation protection method in the embodiment further includes the step S521 of generating a second alarm signal in the case that the resistance value of the positive bus side equivalent insulation resistance after the main positive relay KM is turned on is equal to or less than the second threshold resistance.

[0268] In the embodiment, under the condition that the main positive relay KM is turned on and the main negative relay KN is turned off, if the resistance value of the positive bus side equivalent insulation resistance is equal to or less than the second threshold resistance, it indicates that the equivalent insulation resistances between the shells of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC buses may exceed the safety threshold range. The second alarm signal is generated by the main control module 400 to remind the user to detect the shells of the energy storage battery 100, the energy storage cabinet and the energy storage power station.

[0269] In some embodiments, referring to FIG. 19, the insulation protection method in the embodiment further includes a step S530 of detecting the negative bus side equivalent insulation resistance after the main negative relay KN is turned on and the main positive relay KM is turned off, and controlling the main negative relay to be closed in a case where the resistance value of the negative bus side equivalent insulation resistance is greater than a second threshold resistance.

[0270] In the embodiment, as shown in FIG. 9, in a case where the main negative relay KN is turned on and the main positive relay KM is turned off, there is a second power station equivalent insulation resistance Rn2 between the load negative bus 104 and the electric platform of the energy storage power station, the second power station equivalent insulation resistance Rn2 is equivalent in parallel with the second equivalent insulation resistance Rn1, and the equivalent resistance after parallel connection is the negative bus side equivalent insulation resistance. The main control module 400 can determine the insulation protection state of the energy storage battery 100 according to the resistance value of the negative bus side equivalent insulation resistance. For example, the main control module 400 determines whether the negative bus side equivalent insulation resistance in the case where the main positive relay KM is turned off and the main negative relay KN is turned on exceeds the corresponding threshold range. If the corresponding threshold range is not exceeded, it indicates that the equivalent insulation resistance between the housing of the energy storage battery 100, the energy storage cabinet and the energy storage power station and the corresponding DC bus is within the safety threshold range.

[0271] In some embodiments, referring to FIG. 20, the insulation protection method in the embodiment further includes a step S610 and a step S620.

[0272] In the step S610, the inner side equivalent insulation resistance of the energy storage battery 100 in a single point insulation failure state is detected.

[0273] In the step S620, the position of the single point insulation failure of the energy storage battery 100 is located according to the inner side equivalent insulation resistance of the energy storage battery 100 in the single point insulation failure state.

[0274] In the embodiment, in a case where any one of the battery assemblies 110 in the energy storage battery 100 has a positive or negative electrode short circuit with the housing, it is determined that the energy storage battery 100 has a single point insulation failure problem. When the energy storage battery 100 has a single point insulation failure or a deteriorated working condition, the inner side equivalent insulation resistance of the energy storage battery 100 in the single point insulation failure state is detected, and the position of the single point insulation failure of the energy storage battery 100 is located according to the inner side equivalent insulation resistance of the energy storage battery 100 in the single point insulation failure state, so as to timely remind the user of the insulation failure position, thereby improving the fault elimination efficiency of the energy storage battery 100.

[0275] In some embodiments, referring to FIG. 21, the insulation protection method in the embodiment further includes a step S631, a step S632 and a step S633.

[0276] In step S631, in the case that the first insulation detection unit 510 and the second insulation detection unit 520 are in the on state, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain a second sampling voltage.

[0277] In step S632, in the case that the first sampling voltage is less than the second sampling voltage, the first insulation detection unit 510 is controlled to be in the on state, the second insulation detection unit 520 is controlled to be in the off state, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain a third sampling voltage, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain a fourth sampling voltage.

[0278] In step S633, the internal equivalent insulation resistance of the energy storage battery 100 is calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage, and the ground sampling current.

[0279] In the embodiment, as shown in FIG. 9, the first insulation detection unit 510 is equivalent in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is equivalent in parallel with the second equivalent insulation resistance Rn1. In the first sampling stage, the first insulation detection unit 510 and the second insulation detection unit 520 are controlled to be in the on state, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain a first sampling voltage, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain a second sampling voltage. In the second sampling stage, in the case that the first sampling voltage is less than the second sampling voltage, the first insulation detection unit 510 is controlled to be in the on state, the second insulation detection unit 520 is controlled to be in the off state, the voltage between the positive electrode of the energy storage battery 100 and the ground is sampled to obtain a third sampling voltage, and the voltage between the negative electrode of the energy storage battery 100 and the ground is sampled to obtain a fourth sampling voltage. In this way, the internal equivalent insulation resistance of the energy storage battery can be accurately calculated according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage, and the ground sampling current, which not only improves the accuracy of the internal equivalent insulation resistance of the energy storage battery 100, but also determines whether the energy storage battery 100 has insulation failure based on the internal equivalent insulation resistance.

[0280] In some embodiments, as shown in FIG. 22, the insulation protection method in the embodiment further includes steps S641 and S642.

[0281] In step S641, in the case that the first sampling voltage is greater than or equal to the second sampling voltage, the first insulation detection unit 510 is controlled to be in the off state, the second insulation detection unit 520 is controlled to be in the on state, the voltage between the positive electrode of the energy storage battery 100 and the ground wire is sampled to obtain a fifth sampling voltage, and the voltage between the negative electrode of the energy storage battery and the ground wire is sampled to obtain a sixth sampling voltage.

[0282] In step S642, the inner equivalent insulation resistance of the energy storage battery 100 is calculated according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage, and the ground wire sampling current.

[0283] In the embodiment, as shown in FIG. 9, the first insulation detection unit 510 is equivalent to the first equivalent insulation resistance Rp1 in parallel, and the second insulation detection unit 520 is equivalent to the second equivalent insulation resistance Rn1 in parallel. In the first sampling stage, the first insulation detection unit 510 and the second insulation detection unit 520 are controlled to be in the on state, the voltage between the positive electrode of the energy storage battery 100 and the ground wire is sampled to obtain the first sampling voltage Ua1, and the voltage between the negative electrode of the energy storage battery 100 and the ground wire is sampled to obtain the second sampling voltage Uc1. In the second sampling stage, in the case that the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1, the first insulation detection unit 510 is controlled to be in the off state, the second insulation detection unit 520 is controlled to be in the on state, the voltage between the positive electrode of the energy storage battery 100 and the ground wire is sampled to obtain the fifth sampling voltage Ua3, the voltage between the negative electrode of the energy storage battery 100 and the ground wire is sampled to obtain the sixth sampling voltage Uc3, and the inner equivalent insulation resistance of the energy storage battery 100 is calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3, and the ground wire sampling current. Not only the accuracy of the inner equivalent insulation resistance of the energy storage battery 100 can be improved, but also whether the energy storage battery 100 has insulation failure can be determined based on the inner equivalent insulation resistance.

[0284] In some embodiments, as shown in FIG. 23, the insulation protection method in the embodiment further includes step S650 of determining the single-point insulation failure position of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage, and the ground wire sampling current.

[0285] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rn1. In the case that the first sampling voltage Ua1 is less than the second sampling voltage Uc1, the first voltage between the positive electrode of the energy storage battery 100 and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery 100 and the single-point insulation failure position can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the third sampling voltage Ua2, the fourth sampling voltage Uc2 and the ground sampling current, so that the specific single-point insulation failure position can be determined through the first voltage and the second voltage, and the troubleshooting efficiency of the energy storage battery is improved.

[0286] In some embodiments, referring to FIG. 24, the insulation protection method in the embodiment further includes the step S660 of determining the single-point insulation failure position of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground sampling current.

[0287] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rp1, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rn1, in the case that the first sampling voltage Ua1 is greater than or equal to the second sampling voltage Uc1. The first voltage between the positive electrode of the energy storage battery and the single-point insulation failure position and the second voltage between the negative electrode of the energy storage battery 100 and the single-point insulation failure position can be calculated according to the first sampling voltage Ua1, the second sampling voltage Uc1, the fifth sampling voltage Ua3, the sixth sampling voltage Uc3 and the ground sampling current, so that the specific single-point insulation failure position can be determined through the first voltage and the second voltage, and the troubleshooting efficiency of the energy storage battery 100 is improved.

[0288] In some embodiments, referring to FIG. 25, the insulation protection method in the embodiment further includes the step S670 of determining the insulation deterioration degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

[0289] In the embodiment, the first insulation detection unit 510 is in parallel with the first equivalent insulation resistance Rpl, and the second insulation detection unit 520 is in parallel with the second equivalent insulation resistance Rnl. In the case where the first sampling voltage is less than the second sampling voltage, the internal equivalent insulation resistance of the energy storage battery can be calculated according to the first sampling voltage Ual, the second sampling voltage Ucl, the third sampling voltage A2, the fourth sampling voltage Uc2, and the ground sampling current. Under normal working conditions, the charging and discharging circuit and the shell equivalent insulation resistance are above tens of megaohms due to the protection of the blue film and the insulation material of the energy storage battery 100. When insulation failure or degradation occurs, the equivalent insulation resistance decreases, and thus the insulation degradation severity can be evaluated according to the internal equivalent insulation resistance of the energy storage battery 100.

[0290] In some embodiments, the insulation degradation severity of the energy storage battery 100 can be evaluated by calculating the equivalent insulation degradation resistance Rl of the energy storage battery 100. For example, the ratio of the equivalent insulation degradation resistance Rl of the energy storage battery 100 to the preset equivalent insulation threshold resistance is calculated. The larger the ratio, the greater the resistance value of the equivalent insulation degradation resistance Rl of the energy storage battery 100, and the lighter the insulation degradation degree of the energy storage battery 100. The smaller the ratio, the smaller the resistance value of the equivalent insulation degradation resistance Rl of the energy storage battery 100, and the more serious the insulation degradation degree of the energy storage battery 100.

[0291] In some embodiments, as shown in FIG. 26, in the insulation detection starting stage, the first switch K1 and the second switch K2 are controlled to be closed, and after the first preset time is delayed, the voltage on the positive DC bus 101 and the negative DC bus 102 is sampled to obtain the first sampling voltage Ual and the second sampling voltage Ucl, and the voltage Uol between the current limiting module 200 and the current sampling module 300 is sampled.

[0292] In some embodiments, after the first sampling voltage Ual, the second sampling voltage Ucl, Uol and U1 are sampled, Ual, Ucl, Uol and U1 are verified, and the size of |U1-Ual-Ucl| / U1 and the first preset ratio is calculated. The first preset ratio can be 0.1. If |U1-Ual-Ucl| / U1<0.1, it indicates that the sampling deviation is small, and if |U1-Ual-Ucl| / U1≥0.1, it indicates that the sampling deviation is large, and the user needs to be reminded of the sampling failure and perform troubleshooting.

[0293] In some embodiments, after the first stage voltage sampling ends after the first switch K1 and the second switch K2 are closed, it can be determined whether a single-point insulation failure occurs by determining whether Uol is equal to 0. If yes, it indicates that no current flows through the current limiting module 200. If no, it indicates that a single-point insulation failure can exist.

[0294] In some embodiments, as shown in FIG. 26, after the first stage voltage sampling ends after the first switch K1 and the second switch K2 are closed, the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 can be calculated according to the first sampling voltage Ual and the second sampling voltage Ucl, and the second voltage Uc and the insulation degradation resistance Rl can be calculated according to a corresponding relationship.

[0295] Specifically, if the first sampling voltage Ual is less than the second sampling voltage Ucl, the first insulation detection unit 510 is controlled to be in a conducting state, the second insulation detection unit 520 is controlled to be in a non-conducting state, the third sampling voltage Ua2 is obtained by sampling the voltage between the positive electrode of the energy storage battery 100 and the ground, the fourth sampling voltage Uc2 is obtained by sampling the voltage between the negative electrode of the energy storage battery 100 and the ground, the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 are calculated according to the relationship formula 4 and the relationship formula 5, the second voltage Uc is calculated according to the relationship formula 13, and the insulation degradation resistance Rl is calculated according to the relationship formula 17.

[0296] In another case, if the first sampling voltage Ual is greater than or equal to the second sampling voltage Ucl, the first insulation detection unit 510 is controlled to be in a non-conducting state, the second insulation detection unit 520 is controlled to be in a conducting state, the fifth sampling voltage Ua3 is obtained by sampling the voltage between the positive electrode of the energy storage battery 100 and the ground, the sixth sampling voltage Uc3 is obtained by sampling the voltage between the negative electrode of the energy storage battery 100 and the ground, the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 are calculated according to the relationship formula 8 and the relationship formula 9, the second voltage Uc is calculated according to the relationship formula 16, and the insulation degradation resistance Rl is calculated according to the relationship formula 18.

[0297] In some embodiments, in the second stage of voltage sampling, it is determined whether Uo2 and Uo3 are equal to 0, so as to determine whether a single-point insulation failure occurs. If yes, it indicates that no current flows through the current limiting module 200. If no, it indicates that the energy storage battery 100 can have a single-point insulation failure.

[0298] In some embodiments, the insulation failure position of the energy storage battery 100 can be calculated according to the relationship 14, and the insulation failure severity of the energy storage battery 100 can be evaluated by calculating the insulation deterioration resistance Rl. Further, it can also be judged whether the insulation failure of the energy storage battery 100 occurs by comparing the first equivalent insulation resistance Rp1 and the second equivalent insulation resistance Rn1 with the corresponding threshold resistances.

[0299] The embodiment of the present application provides an energy storage system, which comprises an energy storage battery and an insulation protection circuit according to any one of the above embodiments.

[0300] The embodiment of the present application provides an energy storage system, which comprises an energy storage battery, a current limiting module and a master control module; the energy storage battery comprises a plurality of battery assemblies connected in series, the shells of the battery assemblies are grounded through the current limiting module, and the master control module is used for executing the insulation protection method according to any one of the above embodiments.

[0301] In the embodiment, when the shell of any one of the battery assemblies appears insulation failure, the current of the loop formed by the battery assembly and the ground wire can be limited by the current limiting module, and when double-point insulation failure of the energy storage battery occurs, the current flowing through the current limiting module can be limited, so that the current of the deterioration failure position of the energy storage battery can be limited when insulation failure occurs, the problem of thermal damage of the insulation material at the deterioration position of the energy storage battery can be prevented, the further deterioration trend of the insulation material can be limited, the thermal runaway problem caused by severe discharge can be avoided, and the safety of the energy storage battery is improved.

[0302] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0303] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0304] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e., may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0305] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0306] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An insulation protection circuit for insulation protection of an energy storage battery, characterized in that, The energy storage battery comprises a plurality of battery assemblies connected in series, and the insulation protection circuit comprises: A current limiting module is connected with the housings of the plurality of battery assemblies, and the housings of the plurality of battery assemblies are grounded through the current limiting module.

2. The isolation protection circuit of claim 1, wherein, The housings of the respective battery assemblies are connected with each other through the current limiting module.

3. The isolation protection circuit of claim 1, wherein, The insulation protection circuit comprises: A current sampling module is connected with the current limiting module, and is configured to sample a current flowing through the current limiting module to obtain a ground sampling current. A main control module is connected with the current sampling module, and is configured to determine an insulation protection state of the energy storage battery according to the ground sampling current.

4. The isolation protection circuit of claim 3, wherein, The current limiting module comprises one or more resistor units, and the housings of the plurality of battery assemblies are connected with the current sampling module through the corresponding resistor units.

5. The isolation protection circuit of claim 3, wherein, The insulation protection circuit further comprises: An insulation detection module is connected with a positive electrode of the energy storage battery, a negative electrode of the energy storage battery and a ground wire, and is controlled by the main control module, and is configured to detect an inner equivalent insulation resistance of the energy storage battery. The main control module determines the insulation protection state of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

6. The isolation protection circuit of claim 5, wherein, The insulation detection module comprises: A first insulation detection unit is connected between the positive electrode of the energy storage battery and the current sampling module. A second insulation detection unit is connected between the negative electrode of the energy storage battery and the current sampling module.

7. An insulation detection circuit according to any one of claims 1 to 6, characterized in that, The main control module is further configured to detect the inner equivalent insulation resistance of the energy storage battery before high-voltage power-on of the energy storage battery, and control the high-voltage power-on of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery. The inner equivalent insulation resistance of the energy storage battery comprises a first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground wire and a second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground wire.

8. The isolation protection circuit of claim 7, wherein, The main control module is further configured to detect a positive bus side equivalent insulation resistance and a negative bus side equivalent insulation resistance when the resistance value of the inner equivalent insulation resistance of the energy storage battery is greater than a first threshold resistance, and control the high-voltage power-on of the energy storage battery when the resistance values of the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than a second threshold resistance.

9. The isolation protection circuit of claim 8, wherein, The main control module is specifically configured to detect the positive bus side equivalent insulation resistance after the main positive relay is turned on and the main negative relay is turned off, and determine the insulation protection state of the energy storage battery according to the resistance value of the positive bus side equivalent insulation resistance.

10. The isolation protection circuit of claim 8, wherein, The main control module is specifically configured to detect the negative bus side equivalent insulation resistance after the main negative relay is turned on and the main positive relay is turned off, and control the main negative relay to be closed when the resistance value of the negative bus side equivalent insulation resistance is greater than the second threshold resistance.

11. The isolation protection circuit of claim 6, wherein, The main control module is further configured to detect the inner equivalent insulation resistance of the energy storage battery in a single-point insulation failure state, and locate a position of the single-point insulation failure of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery in the single-point insulation failure state.

12. The isolation protection circuit of claim 11, wherein, The master module is specifically configured to sample a voltage between the positive electrode of the energy storage battery and the ground to obtain a first sampling voltage, sample a voltage between the negative electrode of the energy storage battery and the ground to obtain a second sampling voltage, control the first insulation detection unit to be in a conducting state and the second insulation detection unit to be in an off state, and sample the voltage between the positive electrode of the energy storage battery and the ground to obtain a third sampling voltage, sample the voltage between the negative electrode of the energy storage battery and the ground to obtain a fourth sampling voltage, when the first sampling voltage is less than the second sampling voltage, calculate an inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and a ground sampling current. The inner equivalent insulation resistance of the energy storage battery includes a first equivalent insulation resistance between the positive electrode of the energy storage battery and the ground and a second equivalent insulation resistance between the negative electrode of the energy storage battery and the ground.

13. The isolation protection circuit of claim 12, wherein, The master module is further configured to control the first insulation detection unit to be in an off state and the second insulation detection unit to be in a conducting state, sample a voltage between the positive electrode of the energy storage battery and the ground to obtain a fifth sampling voltage, sample a voltage between the negative electrode of the energy storage battery and the ground to obtain a sixth sampling voltage, when the first sampling voltage is greater than or equal to the second sampling voltage, and calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground sampling current.

14. The isolation protection circuit of claim 12, wherein, The master module is further configured to calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the third sampling voltage, the fourth sampling voltage and the ground sampling current, and determine an insulation deterioration degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

15. The isolation protection circuit of claim 14, wherein, The master module is further configured to calculate the inner equivalent insulation resistance of the energy storage battery according to the first sampling voltage, the second sampling voltage, the fifth sampling voltage, the sixth sampling voltage and the ground sampling current, and determine the insulation deterioration degree of the energy storage battery according to the inner equivalent insulation resistance of the energy storage battery.

16. An insulation protection method for insulating and protecting an energy storage battery, the energy storage battery comprising a plurality of battery assemblies connected in series, characterized in that, The insulation protection method comprises: The housings of the plurality of battery assemblies are connected to the ground through the current limiting module.

17. The method of claim 16, wherein, The insulation protection method further comprises: The inner equivalent insulation resistance of the energy storage battery is detected before the energy storage battery is powered on at a high voltage, and the energy storage battery is powered on at the high voltage according to the inner equivalent insulation resistance of the energy storage battery.

18. The method of claim 17, wherein, The insulation protection method further comprises: The positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are detected when the inner equivalent insulation resistance of the energy storage battery is greater than a first threshold resistance, and the energy storage battery is powered on at the high voltage when the positive bus side equivalent insulation resistance and the negative bus side equivalent insulation resistance are greater than a second threshold resistance.

19. An energy storage system characterized by, The energy storage system comprises an energy storage battery and the insulation protection circuit according to any one of claims 1 to 15, and the insulation protection circuit is connected to the energy storage battery.

20. An energy storage system characterized by, The energy storage system comprises an energy storage battery, a current limiting module and a master control module; the energy storage battery comprises a plurality of battery assemblies connected in series, the housing of the battery assembly is grounded through the current limiting module, and the master control module is used for executing the insulation protection method according to any one of claims 16 to 18.

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