INSPECTION METHOD AND ENERGY STORAGE SYSTEM

This application provides an inspection method, applied to an energy storage system. The energy storage system includes a control unit and multiple energy storage units, and the inspection method is executed by the control unit. The method includes: controlling a first energy storage unit of the multiple energy storage units to discharge to a second energy storage unit of the multiple energy storage units within a first preset time; controlling the second energy storage unit to receive electricity discharged by the first energy storage unit within the first preset time; obtaining first voltage information and first current information of the first energy storage unit; and determining a connection state of the first energy storage unit based on the first voltage information and the first current information. The technical solution of this application can ensure the performance of the energy storage system and maintain the stability of the power grid.

TECHNICAL FIELD

This application relates to the field of power systems, and in particular, to an inspection method and an energy storage system.

BACKGROUND

With the development of society, the load in the power system gradually increases, and the peak-valley difference of the load curve gradually increases. This is detrimental to the stable operation of the power grid. To address this, energy storage technology has been introduced into the power system. An energy storage system can store and release electrical energy to alleviate the pressure on the power grid to some extent.

The performance of the energy storage system is crucial for the operation of the energy storage system and the operation of the power grid. Therefore, how to provide an inspection method to ensure the performance of the energy storage system and maintain the stability of the power grid is a technical problem to be resolved urgently.

SUMMARY

This application provides an inspection method and an energy storage system, which can ensure the performance of the energy storage system and maintain the stability of the power grid.

According to a first aspect, an inspection method is provided and applied to an energy storage system. The energy storage system includes a control unit and multiple energy storage units, and the method is executed by the control unit. The method includes: controlling a first energy storage unit of the multiple energy storage units to discharge to a second energy storage unit of the multiple energy storage units within a first preset time; controlling the second energy storage unit to receive electricity discharged by the first energy storage unit within the first preset time; obtaining first voltage information and first current information of the first energy storage unit, where the first voltage information includes a voltage difference of an output terminal of the first energy storage unit before and after the discharge, and the first current information includes a current flowing through the first energy storage unit during the discharge; and determining a connection state of the first energy storage unit based on the first voltage information and the first current information.

In the embodiments of this application, an inspection method applied to an energy storage system is provided, where the energy storage system includes a control unit and multiple energy storage units, and the method is executed by the control unit. In this method, a first energy storage unit is controlled to discharge to a second energy storage unit within a first preset time, and the second energy storage unit is controlled to receive electricity discharged by the first energy storage unit within the first preset time. First voltage information and first current information of the first energy storage unit are obtained, and a connection state of the first energy storage unit is determined based on the obtained first voltage information and first current information. As the connection state of the energy storage unit is inspected within the energy storage system, an abnormal connection state can be detected in a timely manner, which is conducive to ensuring the safety of the energy storage system. In addition, the inspection method is conducted within the energy storage system, without requiring the transmission of electrical energy between the energy storage system and the power grid, thereby avoiding interference with the normal operation of the power grid and helping to maintain the stability of the power grid.

In a possible implementation, the determining a connection state of the first energy storage unit based on the first voltage information and the first current information includes: determining a first impedance based on the first voltage information and the first current information; and determining the connection state of the first energy storage unit based on whether the first impedance is greater than a first threshold. In this way, the connection state of the first energy storage unit can be determined based on the value of the first impedance, so the inspection method is simple to perform.

In a possible implementation, the determining the connection state of the first energy storage unit based on whether the first impedance is greater than a first threshold includes: determining that the connection state of the first energy storage unit is abnormal under a condition that the first impedance is greater than the first threshold; and/or determining that the connection state of the first energy storage unit is normal under a condition that the first impedance is less than or equal to the first threshold. Thus, it can be determined based on the value of the first impedance whether there is an abnormal connection in the first energy storage unit, such that an abnormal connection can be detected in a timely manner, preventing abnormal connection from causing a phenomenon such as heating or even fire.

In a possible implementation, before the controlling a first energy storage unit of the multiple energy storage units to discharge to a second energy storage unit of the multiple energy storage units within a first preset time, the method further includes determining that the energy storage system is in a resting state or an initial startup state. When no electrical energy is transmitted between the energy storage system and the power grid, inspecting the connection state of the energy storage system is conducive to maintaining the stability of the power grid. Additionally, within the time when the energy storage system is in the resting state, the connection state of the energy storage system is inspected, without occupying the charge or discharge time of the energy storage system. Additionally, under a condition that the energy storage system is in the initial startup state, the connection state of the energy storage system is inspected to find a fault before the energy storage system operates, avoiding the fault during normal operation.

In a possible implementation, the method further includes: controlling a third energy storage unit of the multiple energy storage units to discharge to the second energy storage unit simultaneously with the first energy storage unit within the first preset time. This can prevent a case where the first energy storage unit has insufficient electricity to discharge to the second energy storage unit, allowing the number of energy storage units for discharge to be flexibly set based on an actual condition.

In a possible implementation, the method further includes controlling a fourth energy storage unit of the multiple energy storage units to receive the electricity discharged by the first energy storage unit simultaneously with the second energy storage unit within the first preset time. Thus, the number of energy storage units for discharge and the number of energy storage units to be charged can be set based on actual needs.

In a possible implementation, the first preset time is 10 s-1 min. This ensures that the connection state of the energy storage system can be inspected within a short period of time.

In a possible implementation, the controlling a first energy storage unit of the multiple energy storage units to discharge to a second energy storage unit of the multiple energy storage units within a first preset time includes: sending a first discharge command to the first energy storage unit, such that the first energy storage unit discharges to the second energy storage unit within the first preset time; and the controlling the second energy storage unit to receive electricity discharged by the first energy storage unit within the first preset time includes: sending a first charge command to the second energy storage unit, such that the second energy storage unit receives the electricity discharged by the first energy storage unit within the first preset time. In this way, the first discharge command and/or the first charge command can be sent to control the charge/discharge of the first energy storage unit and the second energy storage unit.

According to a second aspect, an inspection method is provided and applied to an energy storage system. The energy storage system includes a control unit and multiple energy storage units, and the method is executed by a first energy storage unit of the multiple energy storage units. The method includes: under control of the control unit, discharging to a second energy storage unit of the multiple energy storage units within a first preset time; and sending first voltage information and first current information to the control unit. The first voltage information includes a voltage difference of an output terminal of the first energy storage unit before and after the discharge, the first current information includes a current flowing through the first energy storage unit during the discharge, and the first voltage information and the first current information are used for determining a connection state of the first energy storage unit.

According to a third aspect, an energy storage system is provided and includes a control unit and multiple energy storage units. The control unit is configured to: control a first energy storage unit of the multiple energy storage units to discharge to a second energy storage unit of the multiple energy storage units within a first preset time; control the second energy storage unit to receive electricity discharged by the first energy storage unit within the first preset time; and obtain first voltage information and first current information of the first energy storage unit, and determine a connection state of the first energy storage unit based on the first voltage information and the first current information, where the first voltage information includes a voltage difference of an output terminal of the first energy storage unit before and after the discharge, and the first current information includes a current flowing through the first energy storage unit during the discharge.

According to a fourth aspect, a readable storage medium is provided for storing a computer program. When the computer program is executed by a computing device, the computing device implements the inspection method according to the first aspect and second aspect and any possible implementation thereof.

According to a fifth aspect, a control unit is provided, including a processor and a memory, where the memory is used to store a computer program, and the processor is used to invoke the computer program to execute the inspection method according to the first aspect and second aspect and any possible implementation thereof.

In the embodiments of this application, an inspection method applied to an energy storage system is provided, where the energy storage system includes a control unit and multiple energy storage units, and the method is executed by the control unit. In this method, a first energy storage unit is controlled to discharge to a second energy storage unit within a first preset time, and the second energy storage unit is controlled to receive electricity discharged by the first energy storage unit within the first preset time. First voltage information and first current information of the first energy storage unit are obtained, and a connection state of the first energy storage unit is determined based on the obtained first voltage information and first current information. As the connection state of the energy storage unit is inspected within the energy storage system, an abnormal connection state can be detected in a timely manner, which is conducive to ensuring the safety of the energy storage system. In addition, the inspection method is conducted within the energy storage system, without requiring the transmission of electrical energy between the energy storage system and the power grid, thereby avoiding interference with the normal operation of the power grid and helping to maintain the stability of the power grid.

In the accompanying drawings, the figures are not necessarily drawn to scale.

DESCRIPTION OF EMBODIMENTS

The following further describes implementations of this application in detail with reference to the accompanying drawings and embodiments. The detailed description of the embodiments and the accompanying drawings are intended to illustrate the principle of this application, rather than to limit the scope of this application, meaning this application is not limited to the embodiments described herein.

In the description of this application, it should be noted that, unless otherwise stated, “multiple” means at least two; and the orientations or positional relationships indicated by the terms “upper”, “lower”, “left”, “right”, “inside”, “outside”, and the like are merely for ease and brevity of description of this application rather than indicating or implying that the means or components mentioned must have specific orientations or must be constructed or manipulated according to particular orientations. These terms shall therefore not be construed as limitations on this application. In addition, the terms “first”, “second”, “third”, and the like are merely for the purpose of description and shall not be understood as any indication or implication of relative importance. “Perpendicular” is not strictly perpendicular, but within the allowable range of error. “Parallel” is not strictly parallel, but within the allowable range of error.

The orientation terms appearing in the following description all are directions shown in the figures, and do not limit the specific structure of the application. In the description of this application, it should also be noted that unless otherwise specified and defined explicitly, the terms “mounting”, “connection”, and “join” should be understood in their general senses. For example, they may refer to a fixed connection, a detachable connection, or an integral connection, and may refer to a direct connection or an indirect connection via an intermediate medium. Persons of ordinary skill in the art can understand specific meanings of these terms in this application as appropriate to specific situations.

With the development of society, the load in the power system gradually increases, and the peak-valley difference of the load curve gradually increases. This is detrimental to the stable operation of the power grid. To address this, energy storage technology has been introduced into the power system. An energy storage system can store and release electrical energy to alleviate the pressure on the power grid to some extent. The performance of the energy storage system is crucial for the operation of the energy storage system and the operation of the power grid. Therefore, how to provide an inspection method to ensure the performance of the energy storage system and maintain the stability of the power grid is a technical problem to be resolved urgently.

In view of this, the embodiments of this application provide an inspection method applied to an energy storage system, where the energy storage system includes a control unit and multiple energy storage units, and the inspection method of the energy storage system is executed by the control unit. In this method, a first energy storage unit is controlled to discharge to a second energy storage unit within a first preset time, and the second energy storage unit is controlled to receive electricity discharged by the first energy storage unit within the first preset time. First voltage information and first current information of the first energy storage unit are obtained, and a connection state of the first energy storage unit is determined based on the obtained first voltage information and first current information. As the connection state of the energy storage unit is inspected within the energy storage system, an abnormal connection state can be detected in a timely manner, which is conducive to ensuring the safety of the energy storage system. In addition, the inspection method is conducted within the energy storage system, without requiring the transmission of electrical energy between the energy storage system and the power grid, thereby avoiding interference with the normal operation of the power grid and helping to maintain the stability of the power grid.

FIG.1is a schematic diagram of an energy storage system100according to an embodiment of this application. As shown inFIG.1, the energy storage system100may include a control unit110and multiple energy storage units120. The control unit110may be configured for data collection, network monitoring, energy dispatching, and the like. The energy storage units120may be configured to store and release electrical energy.

Optionally, under a condition that the energy storage system100is connected to the power grid180, the energy storage system100may be configured to deliver electrical energy to the power grid180or obtain electrical energy from the power grid180; and the energy storage system100may further be connected to an electric apparatus to provide electrical energy to it.

Optionally, the energy storage system100may alternatively be an electric apparatus, such as an electric vehicle. When the energy storage system100is an electric vehicle, a charging/discharging apparatus can transmit electrical energy between the energy storage system100and the power grid180. In this case, the charging/discharging apparatus may be a bidirectional charging pile or a charging pile that supports the vehicle-to-grid (vehicle to grid, V2G)180mode.

Optionally, the control unit110may be an energy management system (Energy Management System, EMS).

Optionally, the multiple energy storage units120may include a first energy storage unit121and a second energy storage unit122, where the first energy storage unit121and the second energy storage unit122are connected in parallel.

Optionally, the multiple energy storage units120can store the same or different amounts of electrical energy, which can be set according to specific situations and is not particularly limited in the embodiments of this application.

FIG.2is a schematic diagram of an energy storage unit according to an embodiment of this application. As shown inFIG.2, the energy storage unit120may include an energy storage battery system130and a power conversion system (Power Conversion System, PCS), where the energy storage battery system130may include an energy storage battery module131and a battery management system (Battery Management System, BMS).

The energy storage battery system130may be provided with at least one energy storage battery module131, which may include multiple battery cells. The battery cells may be of any type of battery, including but not limited to a lithium-ion battery, a lithium-metal battery, a lithium-sulfur battery, a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, or a lithium-air battery. In terms of the scale of the energy storage battery module131, the energy storage battery module131in the embodiments of the application may be formed by series, parallel, or mixed connection of multiple battery cells, which is not particularly limited in the embodiments of this application.

The power conversion system PCS can be used to control the energy storage unit120or the energy storage battery system130to perform charge or discharge, and the battery management system BMS can be used to monitor the state of the energy storage battery module131.

FIG.3is a schematic diagram of interaction between an energy storage system and a power grid according to an embodiment of this application. As shown inFIG.3, the energy storage system100is connected to a power grid180via a transformer102, thereby achieving the transmission of electrical energy between the energy storage system100and the power grid180.

The transformer102is configured to adjust the voltage on the side of the energy storage system100and the voltage on the side of the power grid180, facilitating the transmission of electrical energy between the energy storage system and the power grid180.

FIG.4is a schematic diagram of an inspection method according to an embodiment of this application. Optionally, the method200of the embodiments of the application is applicable to the energy storage system100shown inFIG.1.

As shown inFIG.4, the inspection method200can include the following steps:

Step210: Control a first energy storage unit121of the multiple energy storage units120to discharge to a second energy storage unit122of the multiple energy storage units120within a first preset time.

Optionally, the first energy storage unit121and the second energy storage unit122are connected in parallel. The control unit110controls the first energy storage unit121to discharge to the second energy storage unit122within the first preset time. In this process, a current flowing through the first energy storage unit121and the second energy storage unit122can be generated.

Optionally, the control unit110can control the first power conversion system PCS of the first energy storage unit121, so that the first PCS controls the first BMS of the first energy storage unit121, and the first BMS controls the energy storage battery module131of the first energy storage unit121to discharge.

Step220: Control the second energy storage unit122to receive electricity discharged by the first energy storage unit121within the first preset time.

Optionally, the control unit110can control the second PCS of the second energy storage unit122, so that the second PCS controls the second BMS of the second energy storage unit122, and the second BMS controls the energy storage battery module131of the second energy storage unit122to charge.

Optionally, within the first preset time, the control unit110controls the first energy storage unit121to discharge to the second energy storage unit122, or controls the second energy storage unit122to receive the electricity released by the first energy storage unit121, thereby forming a loop between the first energy storage unit121and the second energy storage unit122. In other words, within the first preset time, under the control of the control unit110, the first energy storage unit121acts as a power source and the second energy storage unit122acts as a load.

Step230: Obtain first voltage information and first current information of the first energy storage unit121. The first voltage information includes the voltage difference of an output terminal of the first energy storage unit121before and after the discharge, and the first current information includes a current flowing through the first energy storage unit121during the discharge.

Optionally, the step of obtaining the first voltage information of the first energy storage unit121includes: obtaining a voltage U1of the output terminal of the first energy storage unit121before the discharge; and/or obtaining a voltage U2of the output terminal of the first energy storage unit121after the discharge.

The first voltage information includes the voltage difference of the output terminal of the first energy storage unit121before and after the discharge, and optionally the voltage difference is U1−U2.

The first current information includes the current flowing through the first energy storage unit121during the discharge, meaning that the first current information includes a current I flowing through the first energy storage unit121within the first preset time, and the current I can remain constant within the first preset time.

Optionally, the voltages U1and U2and the current I can be measured by the first BMS.

Optionally, within the first preset time, the current I2flowing through the second energy storage unit may be the same as or different from the current I flowing through the first energy storage unit, which is not particularly limited in the embodiments of this application and can be set based on an actual condition. For example, when the structures of the first energy storage unit121and the second energy storage unit122are the same, I2=I. In another example, when the structures of the first energy storage unit121and the second energy storage unit122are different, I2may be made equal to I through the adjustment of the second PCS, or certainly I2may be made not equal to I. In other words, the current I2flowing through the second energy storage unit122can be adjusted by the second PCS.

Step240: Determine a connection state of the first energy storage unit based on the first voltage information and the first current information.

The embodiments of this application provide an inspection method. In this method, a first energy storage unit is controlled to discharge to a second energy storage unit within a first preset time, and the second energy storage unit is controlled to receive electricity discharged by the first energy storage unit within the first preset time, thus forming a loop between the first energy storage unit and the second energy storage unit. The first voltage information and first current information of the first energy storage unit are obtained, and the connection state of the first energy storage unit is determined based on the first voltage information and the first current information. The first voltage information includes the voltage difference of an output terminal of the first energy storage unit before and after the discharge, and the first current information includes a current flowing through the first energy storage unit during the discharge. In this way, the connection state of the first energy storage unit can be determined based on the first voltage information and the first current information, thereby detecting an abnormal connection state of the energy storage system, which is conducive to ensuring the safety of the energy storage system. In addition, the inspection method is conducted within the energy storage system, without requiring the transmission of electrical energy between the energy storage system and the power grid, thereby avoiding interference with the normal operation of the power grid and helping to maintain the stability of the power grid.

FIG.5is a flowchart of an inspection method according to an embodiment of this application. Optionally, in an embodiment of this application, as shown inFIG.5, the step of determining the connection state of the first energy storage unit121based on the first voltage information and the first current information includes the following steps:

Step310: Determine a first impedance based on the first voltage information and the first current information.

Specifically, the control unit110can calculate the value of the first impedance based on the first voltage information and the first current information. The value of the first impedance R may be the ratio of the voltage difference of the output terminal of the first energy storage unit121before and after the discharge to the current I flowing through the first energy storage unit121during the discharge, that is, R=(U1−U2)/I.

Step320: Determine the connection state of the first energy storage unit121based on whether the first impedance is greater than a first threshold.

In this embodiment, the first impedance is determined based on the first voltage information and the first current information, and the connection state of the first energy storage unit is determined based on the relationship between the value of the first impedance and the first threshold. In this way, the size of the first impedance can serve as an indicator to intuitively reflect the connection state of the first energy storage unit, so the inspection method is simple to perform.

Optionally, in an embodiment of this application, the step of determining the connection state of the first energy storage unit121based on whether the first impedance is greater than the first threshold includes: determining that the connection state of the first energy storage unit121is abnormal under a condition that the first impedance is greater than the first threshold; and/or determining that the connection state of the first energy storage unit121is normal under a condition that the first impedance is less than or equal to the first threshold.

Optionally, an abnormal connection state of the first energy storage unit121may refer to a loose connection in the loop of the first energy storage unit121. Under a condition of a loose connection in the loop of the first energy storage unit121, an impedance value at the position of the loose connection fault is greater than an impedance value when no loose connection fault occurs in the loop. The loose connection may affect the normal operation of the first energy storage unit121, causing the first energy storage unit121to heat abnormally or even catch a fire.

Optionally, the first threshold is the maximum value within the normal range of impedance at the output terminal of the first energy storage unit121when the connection state is normal. If the first impedance is greater than the first threshold, the control unit110can determine that the impedance value at the output terminal of the first energy storage unit121is abnormal, indicating a loose connection in the loop of the first energy storage unit121, such as poor contact at the output terminal. If the first impedance is equal to or less than the first threshold, the control unit110can determine that the impedance value at the output terminal of the first energy storage unit121is normal, that is, the connection state of the first energy storage unit121is normal without loose connection.

Optionally, the first threshold is set differently based on the actual structure of the first energy storage unit121, for example, a different capacitance of the first energy storage unit121, which is not limited in the embodiments of this application.

A loose connection is determined in the loop of the first energy storage unit under the condition that the value of the first impedance is greater than the first threshold, and no loose connection is determined in the loop of the first energy storage unit under the condition that the value of the first impedance is less than or equal to the first threshold. Thus, the loose connection fault of the first energy storage unit can be determined based on the value of the first impedance, thereby avoiding the phenomenon caused by the loose connection such as abnormal heating or even fire, ensuring the safety of the energy storage system.

Optionally, in an embodiment of this application, before the first energy storage unit121of the multiple energy storage units120is controlled to discharge to the second energy storage unit122of the multiple energy storage units120within the first preset time, the method200further includes: determining that the energy storage system100is in a resting state or an initial startup state.

Optionally, the resting state refers to the state where the energy storage system100neither delivers electrical energy to the power grid180nor obtains electrical energy from the power grid180.

Optionally, the initial startup state refers to the state where the energy storage system100has not yet started operating but has just been started. For example, for an energy storage system100such as an electric vehicle, the initial startup state refers to the state where the electric vehicle has just started the ignition but has not yet started to drive.

When the energy storage system100is in the resting state, the connection state of the first energy storage unit of the energy storage system100is inspected. The inspection method only needs to be carried out within the energy storage system100, without the cooperation of the power grid, that is, without delivering electrical energy to or obtaining electrical energy from the power grid, thus not affecting the normal operation of the power grid and helping to maintain the stability of the power grid. In addition, within the time when the energy storage system100is in the resting state, the connection state of the energy storage system100is inspected, without occupying the charge or discharge time of the energy storage system100.

Under a condition that the energy storage system100is in the initial startup state, the connection state of the energy storage system100is inspected to find a fault before the energy storage system100operates, avoiding the fault during normal operation.

FIG.6is a schematic diagram of an energy storage system according to an embodiment of this application. As shown inFIG.6, the energy storage system100includes a first energy storage unit121, a second energy storage unit122, a third energy storage unit123, and a fourth energy storage unit124connected in parallel, where electricity can be transmitted between the energy storage units via a bus101.

Optionally, in an embodiment of this application, the method200further includes: controlling the third energy storage unit123of the multiple energy storage units120to discharge to the second energy storage unit122simultaneously with the first energy storage unit121within the first preset time.

Optionally, the control unit110can control the third energy storage unit123and the first energy storage unit121to discharge to the second energy storage unit122simultaneously within the first preset time, thereby forming a loop among the first energy storage unit121, the second energy storage unit122, and the third energy storage unit123, with the first energy storage unit121and the third energy storage unit123used as power sources and the second energy storage unit122as a load, thus avoiding a case where the first energy storage unit121has insufficient electricity to discharge to the second energy storage unit122. In this way, the number of discharging energy storage units can be flexibly set based on an actual condition.

Optionally, the control unit110may alternatively control other energy storage units of the multiple energy storage units120to discharge to the second energy storage unit122within the first preset time. For example, the first energy storage unit121, the third energy storage unit123, and the fifth energy storage unit simultaneously discharge to the second energy storage unit122within the first preset time. In other words, the number of energy storage units for discharge to the second energy storage unit122can be set based on an actual condition, such as the electricity of each energy storage unit, which is not particularly limited in the embodiments of this application.

Optionally, in an embodiment of this application, the method200further includes: controlling a fourth energy storage unit124of the multiple energy storage units120to receive the electricity discharged by the first energy storage unit121simultaneously with the second energy storage unit122within the first preset time.

Optionally, the fourth energy storage unit124and the second energy storage unit122simultaneously receive the electricity discharged by the first energy storage unit121within the first preset time.

Optionally, the fourth energy storage unit124and the second energy storage unit122simultaneously receive the electricity discharged by the first energy storage unit121and the third energy storage unit123within the first preset time.

The number of energy storage units discharging electricity and the number of energy storage units receiving electricity can be set based on actual conditions, which is not particularly limited in the embodiments of this application.

Optionally, in an embodiment of this application, the first preset time is 10 s-1 min. In this way, it can be quickly detected within a short period of time whether the connection state of the energy storage system100is abnormal.

The specific value of the first preset time can be set based on an actual condition, which is not particularly limited in the embodiments of this application.

Optionally, in an embodiment of this application, the step of controlling the first energy storage unit121of the multiple energy storage units120to discharge to the second energy storage unit122of the multiple energy storage units120within the first preset time includes: sending a first discharge command to the first energy storage unit121, such that the first energy storage unit121discharges to the second energy storage unit122within the first preset time; and the step of controlling the second energy storage unit122to receive electricity discharged by the first energy storage unit121within the first preset time includes: sending a first charge command to the second energy storage unit122, such that the second energy storage unit122receives the electricity discharged by the first energy storage unit121within the first preset time. In this way, the first discharge command and/or the first charge command can be sent to control the charge/discharge of the first energy storage unit121and the second energy storage unit122.

Optionally, the control unit110can further control the charge/discharge of the first energy storage unit121and the second energy storage unit122by other means than sending the charge/discharge command, which is not particularly limited in the embodiments of this application.

FIG.7is a schematic diagram of an inspection method according to an embodiment of this application. As shown inFIG.7, the method specifically includes the following steps:

Step410: Under control of the control unit110, discharge to a second energy storage unit122of the multiple energy storage units120within a first preset time.

Optionally, the first energy storage unit121receives the first discharge command sent by the control unit110and discharges to the second energy storage unit122according to the first discharge command. Correspondingly, the second energy storage unit122receives the first charge command sent by the control unit110and receives the electricity discharged by the first energy storage unit121according to the first charge command.

Step420: Send first voltage information and first current information to the control unit110. The first voltage information includes a voltage difference of an output terminal of the first energy storage unit121before and after the discharge, the first current information includes a current flowing through the first energy storage unit122during the discharge, and the first voltage information and the first current information are used for determining a connection state of the first energy storage unit122.

Specifically, steps410and420are executed by the first energy storage unit121of the multiple energy storage units120.

The method embodiments of this application have been described in detail above with reference toFIGS.1to6, and embodiments of the energy storage system of this application are described in detail below. It should be understood that the method embodiments correspond to the system embodiments, and similar descriptions can be referred to in the method embodiments.

The embodiments of this application provide an energy storage system100, where the energy storage system100includes a control unit110and multiple energy storage units120. The control unit110is configured to: control a first energy storage unit121of the multiple energy storage units120to discharge to a second energy storage unit122of the multiple energy storage units120within a first preset time; control the second energy storage unit122to receive electricity discharged by the first energy storage unit121within the first preset time; and obtain first voltage information and first current information of the first energy storage unit121, and determine a connection state of the first energy storage unit121based on the first voltage information and the first current information, where the first voltage information includes a voltage difference of an output terminal of the first energy storage unit121before and after the discharge, and the first current information includes a current flowing through the first energy storage unit121during the discharge.

Optionally, in an embodiment of this application, the control unit110is configured to: determine a first impedance based on the first voltage information and the first current information; and determine the connection state of the first energy storage unit121based on whether the first impedance is greater than a first threshold.

Optionally, in an embodiment of this application, the control unit110is configured to: determine that the connection state of the first energy storage unit121is abnormal under a condition that the first impedance is greater than the first threshold; and/or determine that the connection state of the first energy storage unit121is normal under a condition that the first impedance is less than or equal to the first threshold.

Optionally, in an embodiment of this application, the control unit110is configured to: under a condition that the energy storage system100is determined to be in a resting state or initial startup state, control the first energy storage unit121to discharge to the second energy storage unit122within the first preset time.

Optionally, in an embodiment of this application, the control unit110is further configured to control a third energy storage unit123of the multiple energy storage units120to discharge to the second energy storage unit122simultaneously with the first energy storage unit121within the first preset time.

Optionally, in an embodiment of this application, the control unit110is further configured to control a fourth energy storage unit124of the multiple energy storage units120to receive the electricity discharged by the first energy storage unit121simultaneously with the second energy storage unit122within the first preset time.

Optionally, in an embodiment of this application, the control unit110is configured to: send a first discharge command to the first energy storage unit121, such that the first energy storage unit121discharges to the second energy storage unit122within the first preset time; and send a first charge command to the second energy storage unit122, such that the second energy storage unit122receives the electricity discharged by the first energy storage unit121within the first preset time.

FIG.8is a schematic diagram of a circuit structure of a first energy storage unit according to an embodiment of this application. Optionally, in an embodiment of this application, as show inFIG.8, the first energy storage unit121includes a first power conversion system PCS1211and a first energy storage battery system1212, and the first energy storage battery system1212includes a first energy storage battery module1213and a first battery management system BMS1214; the first PCS1211is configured to receive the first discharge command and send the first discharge command to the first BMS1214; and the first BMS1214is configured to control, based on the first discharge command, the first energy storage battery module1213to discharge.

Optionally, in an embodiment of this application, the first BMS is further configured to measure a first voltage and a first current and send the first voltage and the first current to the first PCS; and the first PCS is further configured to send the first voltage and the first current to the control unit110.

Optionally, the first voltage is the voltage at point al of the output terminal of the first energy storage unit121after discharge, and the first current is the current flowing through the first energy storage unit121during the discharge.

Optionally, the first BMS is further configured to measure a second voltage and send the second voltage to the first PCS, and the first PCS is configured to send the second voltage to the control unit110. The second voltage is the voltage at point al of the output terminal of the first energy storage unit121before discharge.

Optionally, a direct-current high-voltage box131may act as a switch for discharging or charging the first energy storage battery module1213and can discharge upon receiving the first discharge command sent by the first BMS.

FIG.9is a schematic diagram of a circuit structure of a second energy storage unit according to an embodiment of this application. Optionally, in an embodiment of this application, as shown inFIG.9, the second energy storage unit122includes a second power conversion system PCS1221and a second energy storage battery system1222, and the second energy storage battery system1222includes a second energy storage battery module1223and a second battery management system BMS1224; the second PCS1221is configured to receive the first charge command and send the first charge command to the second BMS1224; and the second BMS1224is configured to control, based on the first charge command, the second energy storage battery module1223to discharge.

The embodiments of this application provide a readable storage medium for storing a computer program. When the computer program is executed by a computing device, the computing device implements the inspection method according to any one of the aforementioned embodiments.

The embodiments of this application provide a computer program, the computer program includes instructions, and when the computer program is executed by a computer, the computer can perform the inspection method according to any one of the aforementioned embodiments.

FIG.10is a schematic diagram of a control unit according to an embodiment of this application. As shown inFIG.10, the embodiments of this application provide a control unit110, including a processor111and a memory112, where the memory112is used to store a computer program, and the processor111is used to invoke the computer program to perform the inspection method according to any one of the aforementioned embodiments.

The processor111in this embodiment of this application may be an integrated circuit chip with a signal processing capability. In an implementation process, steps in the foregoing method embodiments can be implemented by using a hardware integrated logic circuit in the processor, or by using instructions in a form of software. The foregoing processor may be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or another programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The processor may implement or execute methods and steps disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor, or the processor may also be any conventional processor or the like. The steps of the methods disclosed with reference to the embodiments of this application may be directly implemented by a hardware decoding processor, or may be implemented by a combination of hardware and software modules in a decoding processor. The software module may be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or electrically erasable programmable memory, or a register. The storage medium is located in the memory, and the processor reads information in the memory and completes the steps in the foregoing methods in combination with hardware of the processor.

It should be understood that the specific examples herein are intended only to assist those skilled in the art to better understand the embodiments of this application, but not to limit the scope of the embodiments of this application.

It should be also understood that sequence numbers of processes in various embodiments of this application do not mean execution sequences. The execution sequences of the processes should be determined based on functions and internal logic of the processes, and should not be construed as any limitation on implementation processes of the embodiments of this application.

It should be further understood that various embodiments described in this specification may be implemented separately or may be implemented in combination with each other, which is not limited in the embodiments of this application.

Although this application has been described with reference to the preferred embodiments, various modifications can be made to this application without departing from the scope of this application and the components therein can be replaced with equivalents. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner. This application is not limited to the specific embodiments disclosed in this specification, but includes all technical solutions falling within the scope of the claims.