A test method and test platform for towing test of energy storage battery prefabricated cabin

Abstract

The present invention discloses a test method and a test platform for a towing test of a prefabricated energy storage battery cabin, which are used in the field of charge and discharge performance evaluation of a prefabricated energy storage battery cabin. The test method comprises the following steps: powering on the test equipment of the test platform; the battery pack in the prefabricated energy storage battery cabin starts to send real-time status information, and feeds back the real-time status information to the energy management system and the converter control system; the test mode is selected according to the test requirements, and a power control instruction is issued to the converter control system according to the set test process; the prefabricated energy storage battery cabin is controlled to perform a charge and discharge test according to the power curve information; when the battery pack reaches the set cut-off state, a zero power instruction is issued to the converter control system, the test is terminated, the test results are derived, and a test report is generated. The present invention automatically sends instructions for charge and discharge test and mode conversion according to the set program according to the test plan, and the automatic test degree is high.

Description

Technical Field

[0001] The present invention relates to the field of charge and discharge performance evaluation of a prefabricated energy storage battery cabin, and in particular to a test method and a test platform for a towing test of a prefabricated energy storage battery cabin. Background Art

[0002] With the continuous advancement of electrochemical energy storage technology, energy storage technology plays a pivotal role in the energy Internet. Energy storage power stations are mainly used for peak and frequency regulation on the grid side and for smoothing the power fluctuation of new energy on the power generation side. Battery energy storage power stations have developed rapidly due to their advantages such as short construction period, small footprint and flexible deployment. They have been widely used in renewable energy, smart grid, distributed energy, off-grid microgrid, industrial energy saving, emergency power supply, rail transportation and other fields.

[0003] In recent years, electrochemical energy storage represented by lithium-ion batteries has developed rapidly due to its advantages such as high energy storage density and power density, high efficiency, rapid technological progress, and great development potential. With the development of the energy storage industry, how to detect the battery performance of energy storage power stations and whether they can meet the design requirements, evaluate the performance of battery packs in advance, shorten the on-site commissioning cycle of energy storage power stations, and ensure the quality of equipment commissioning has become an important issue that needs to be solved urgently.

[0004] Compared with conventional substations, battery energy storage power stations are quite different in structure and function. Due to the high integration and particularity of batteries and battery management systems (BMS) and power conversion systems (PCS), the current microcomputer-based relay protection test method based on analog signals and physical input and output cannot meet the test requirements of battery energy storage power stations, and the high voltage, high current and actual power load required for the test are difficult to obtain.

[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0006] In order to overcome the above problems, the present invention aims to propose a test method and a test platform for towing tests of prefabricated energy storage battery cabins, with the aim of solving the problem that the current microcomputer-based relay protection test method based on analog signals and physical input and output cannot meet the test requirements of battery energy storage power stations well, and the high voltage, high current and actual power load required for the test are difficult to obtain.

[0007] To this end, the specific technical solution adopted by the present invention is as follows:

[0008] According to one aspect of the present invention, a test method for a towing test of a prefabricated energy storage battery cabin is provided, and the test method for a towing test of a prefabricated energy storage battery cabin comprises the following steps:

[0009] S1. Power on the devices on the test platform to ensure that each device is in normal condition and completes self-test;

[0010] S2. After completing the equipment self-test, the battery pack in the energy storage battery prefabricated cabin starts to send real-time status information, and feeds back the real-time status information to the energy management system and the converter control system through the battery management system;

[0011] S3. Selecting a test mode in the energy management system according to the test requirements, and issuing a power control instruction to the converter control system according to the set test process;

[0012] S4. After receiving the power control command from the energy management system, the converter control system controls the energy storage battery prefabricated cabin to perform charging and discharging tests according to the power curve information, and the energy management system monitors the test process in real time;

[0013] S5. When the battery pack reaches the set cut-off state, the energy management system immediately sends a zero power command to the converter control system, terminates the test, exports the test results and generates a test report.

[0014] Optionally, powering on the test equipment to ensure that each device is in a normal state and completes self-test includes the following steps:

[0015] S11. Power on the test equipment to ensure that each device is in normal status, and connect the frame circuit breakers in the incoming cabinet and the combiner cabinet to the energy management system of the test cabinet through the RS485 communication interface;

[0016] S12, after the communication signal passes through the protocol conversion device, it is connected to the energy management system through the switch;

[0017] S13, the converter control system and the battery management system of the energy storage battery prefabricated cabin are connected to the energy management system through the IEC61850 protocol.

[0018] Optionally, after completing the equipment self-test, the battery pack in the energy storage battery prefabricated compartment starts to send real-time status information, and the real-time status information is fed back to the energy management system and the converter control system through the battery management system, including the following steps:

[0019] S21, start the battery management system in the energy storage battery prefabricated cabin, and establish RS485 communication and CAN communication networks with the energy management system and converter control system;

[0020] S22, using the battery management system to collect real-time status information of the battery pack, and sending it to the energy management system and the converter control system through RS485 communication and CAN communication network;

[0021] S23, the energy management system and the converter control system receive the real-time status information from the battery management system and process the real-time status information;

[0022] S24. Based on the processing result, the energy management system uses the received status information to perform real-time monitoring and adjusts the power output or test process of the converter control system as needed;

[0023] S25. The battery management system ensures the logical interlocking and operation management of the test system, triggers safety protection measures or stops the test.

[0024] Optionally, the energy management system and the converter control system receive the real-time status information from the battery management system, and process the real-time status information, including the following steps:

[0025] S231, the energy management system and the converter control system receive real-time status information data sent by the battery management system through a predetermined communication interface;

[0026] S232, the received real-time status information data is parsed by the protocol parsing module inside the energy management system and the converter control system, and key status data of the battery pack is extracted;

[0027] S233, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack;

[0028] S234. Based on the analysis results and the preset control logic, the energy management system generates and issues control instructions to adjust the power output of the converter control system.

[0029] Optionally, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack, including the following steps:

[0030] S2331, analyzing and cleaning key status data of the battery pack;

[0031] S2332, dividing the battery pack status data after cleaning into grids according to multiple target dimensions, and creating a corresponding hypercube structure;

[0032] S2333, calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function, and calculating the information entropy of the entire solution set based on the density values ​​of all solution points;

[0033] S2334, continuously monitor the change of information entropy in the entire solution set;

[0034] S2335. When the information entropy value remains stable within a preset range, the battery pack status analysis is considered to be completed, the calculation is terminated in advance, and the current operating status and trend of the battery pack are obtained.

[0035] Optionally, calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function, and calculating the information entropy of the entire solution set based on the density values ​​of all solution points includes the following steps:

[0036] S23331. Divide each data point into a corresponding hypercube structure according to the target dimension of the battery pack status data;

[0037] S23332. For each solution point, calculate the Euclidean distance between the current solution point and other solution points;

[0038] S23333. Select the Gaussian influence function as the function for measuring the influence between solution points;

[0039] S23334. For each solution point, based on the distance between the current solution point and other solution points, calculate the density value by using the Gaussian influence function;

[0040] S23335. Standardize the density values ​​of all solution points and calculate the information entropy of the entire solution set according to the Shannon entropy formula.

[0041] Optionally, the expression for calculating the density value by the Gaussian influence function is:

[0042]

[0043] In the formula, Ω(l i →y) represents the solution point l in the battery status data point i The impact on the solution point y;

[0044] l i represents the i-th solution point of the battery pack state;

[0045] y represents the yth solution point of the battery pack state;

[0046] σ represents the normal fluctuation range allowed between solution points in the battery pack state data;

[0047] e represents the base of natural logarithm;

[0048] (l i -y) 2 Indicates the solution point l in the battery status data point i The square of the Euclidean distance from the solution point y.

[0049] Optionally, the battery management system ensures the logic lockout and operation management of the test system, triggering safety protection measures or stopping the test including the following steps:

[0050] S251, the battery management system monitors the key status parameters of the battery pack in real time;

[0051] S252. Perform logical judgment on each operation to ensure that all steps in the test process comply with preset safety rules;

[0052] S253. When an abnormal state is detected, the battery management system immediately triggers a preset safety protection mechanism;

[0053] S254: If the battery management system detects that the critical state reaches the emergency shutdown condition, it sends a command to stop the test immediately;

[0054] S255. After stopping the test, record all relevant status data and triggered protection measures.

[0055] Optionally, the test modes include grid-connected charging, grid-connected towing, and off-grid towing.

[0056] According to another aspect of the present invention, a test platform for a towing test of a prefabricated energy storage battery cabin is provided. The test platform for the towing test of a prefabricated energy storage battery cabin comprises a test device, and the test device comprises a frame base, and a test cabinet, an incoming line cabinet, a junction cabinet, an isolation transformer cabinet, a first converter control system module and a second converter control system module are sequentially arranged on the surface of the frame base.

[0057] Compared with the prior art, this application has the following beneficial effects:

[0058] 1. The entire test platform in the present invention is prefabricated in the factory, with a compact size, small footprint, modular assembly, flexible and fast transportation, and can be towed away, effectively solving the problems of complex and cumbersome equipment and difficult experimental environment construction during battery pack performance evaluation; the test platform can meet multiple charging and discharging modes such as grid-connected charging, grid-connected towing, and off-grid towing, with integrated functions, saving materials, and improving the efficiency of battery performance evaluation; the host computer of the test cabinet can collect power information of the two-way metering multifunctional meter of the incoming cabinet, and control the incoming cabinet circuit breaker to trip the incoming circuit breaker according to the set reverse power threshold and delay time when reverse power is detected to prevent reverse power transmission; the energy management system EMS of the test cabinet can communicate with the converter PCS and the battery management system BMS of the battery prefabricated cabin, and automatically send instructions for charging and discharging tests (the rate can be set, the cut-off condition can be set) and mode conversion according to the test plan and the set program, with a high degree of automatic testing to avoid manual repeated settings.

[0059] 2. The present invention divides the data into multi-dimensional grids and uses Gaussian influence function to calculate the density of solution points, so as to accurately describe the distribution of battery pack status in multi-dimensional space. By calculating the information entropy, the changes in the battery pack status distribution can be effectively tracked, and the operating trend of the battery pack can be identified. Based on the real-time analysis results of the battery pack status data, the energy management system can dynamically adjust the power output and other parameters of the inverter control system, and use Gaussian influence function and information entropy to measure the concentration of the battery pack status distribution. In the processing and trend analysis of multi-dimensional data, abnormal battery conditions, such as overheating, overcharging and other risk factors, can be identified earlier. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The above characteristics, features and advantages of the present invention and their implementation methods and methods will become more clearly understood in conjunction with the following description of the embodiments, which are described in detail in conjunction with the accompanying drawings. Herein, a schematic diagram is shown:

[0061] Figure 1 is a flow chart of a test method for a towing test of a prefabricated energy storage battery cabin according to an embodiment of the present invention;

[0062] Figure 2 is a structural schematic diagram of a test platform for towing tests of energy storage battery prefabricated cabins according to an embodiment of the present invention;

[0063] Figure 3 It is a power control model diagram of a converter PCS in a test method for a towing test of a prefabricated energy storage battery cabin according to an embodiment of the present invention;

[0064] Figure 4 It is a primary system diagram of a towing test platform for a prefabricated energy storage battery cabin in a test method for towing test of a prefabricated energy storage battery cabin according to an embodiment of the present invention;

[0065] Figure 5 It is a communication topology diagram of a test platform for towing a prefabricated energy storage battery cabin in a test method for towing a prefabricated energy storage battery cabin according to an embodiment of the present invention.

[0066] In the figure:

[0067] 1. Frame base; 2. Test cabinet; 3. Incoming cabinet; 4. Combiner cabinet; 5. Isolation transformer cabinet; 6. First converter control system module; 7. Second converter control system module. DETAILED DESCRIPTION

[0068] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0069] According to an embodiment of the present invention, a test method and a test platform for a towing test of a prefabricated energy storage battery cabin are provided.

[0070] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 and Figure 5 As shown, according to one embodiment of the present invention, a test method for a towing test of a prefabricated energy storage battery cabin is provided, and the test method for a towing test of a prefabricated energy storage battery cabin comprises the following steps:

[0071] S1. Power on the devices on the test platform to ensure that each device is in normal status and completes self-test.

[0072] Preferably, powering on the test equipment to ensure that each device is in a normal state and completes self-testing includes the following steps:

[0073] S11. Power on the test equipment to ensure that each device is in normal status, and connect the frame circuit breakers in the incoming cabinet and the combiner cabinet to the energy management system of the test cabinet through the RS485 communication interface;

[0074] S12, after the communication signal passes through the protocol conversion device, it is connected to the energy management system through the switch;

[0075] S13, the converter control system and the battery management system of the energy storage battery prefabricated cabin are connected to the energy management system through the IEC61850 protocol.

[0076] It should be explained that the energy management system (EMS) can realize power allocation and command issuance according to the chargeable / dischargeable amount of the power conversion system (PCS). During the charging and discharging towing test of two sets of energy storage battery prefabricated cabins, the front acquisition module of the energy management system can collect and obtain the state parameters of the battery cells, battery modules and battery clusters, including the single voltage of the battery cell, the total voltage, the voltage range of the battery module, the maximum temperature rise of the battery cell, the temperature range of the battery cell, the state of charge (SOC), the charge and discharge energy, etc.

[0077] Power on the test equipment and ensure that all equipment is in normal status, including the frame circuit breakers in the incoming cabinet and the combiner cabinet; the equipment is connected to the energy management system of the test cabinet through the RS485 communication interface; after the communication signal passes through the protocol conversion device, it is connected to the energy management system through the switch for data exchange and transmission of control instructions; at the same time, the converter control system and the battery management system of the energy storage battery prefabricated cabin are connected to the energy management system through the IEC61850 protocol to achieve efficient data communication and coordinated control.

[0078] S2. After completing the equipment self-test, the battery pack in the energy storage battery prefabricated cabin starts to send real-time status information, and feeds back the real-time status information to the energy management system and the converter control system through the battery management system.

[0079] Preferably, after completing the equipment self-test, the battery pack in the energy storage battery prefabricated compartment starts to send real-time status information, and the real-time status information is fed back to the energy management system and the converter control system through the battery management system, including the following steps:

[0080] S21, start the battery management system in the energy storage battery prefabricated cabin, and establish RS485 communication and CAN communication networks with the energy management system and converter control system.

[0081] S22. Use the battery management system to collect real-time status information of the battery pack and send it to the energy management system and converter control system through RS485 communication and CAN communication network.

[0082] S23, the energy management system and the converter control system receive the real-time status information from the battery management system and process the real-time status information.

[0083] Preferably, the energy management system and the converter control system receive the real-time status information from the battery management system, and process the real-time status information including the following steps:

[0084] S231, the energy management system and the converter control system receive real-time status information data sent by the battery management system through a predetermined communication interface;

[0085] S232, the received real-time status information data is parsed by the protocol parsing module inside the energy management system and the converter control system, and key status data of the battery pack is extracted;

[0086] S233, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack;

[0087] S234. Based on the analysis results and the preset control logic, the energy management system generates and issues control instructions to adjust the power output of the converter control system.

[0088] It should be explained that the energy management system and the converter control system receive real-time status information data from the battery management system through a predetermined communication interface; the real-time status information data includes key status parameters of the battery pack, such as voltage, temperature, SOC, etc. The received data is parsed by the protocol parsing module inside the energy management system and the converter control system, and the key status data is extracted. Then, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack; based on the analysis results and the preset control logic, the energy management system generates and issues control instructions to adjust the power output of the converter control system to achieve optimal management and control of the battery pack; this process ensures that the energy management system and the converter control system monitor and manage the battery pack status in real time, thereby improving the efficiency and reliability of the system.

[0089] Preferably, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack, including the following steps:

[0090] S2331, analyzing and cleaning key status data of the battery pack;

[0091] S2332, dividing the battery pack status data after cleaning into grids according to multiple target dimensions, and creating a corresponding hypercube structure;

[0092] S2333, calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function, and calculating the information entropy of the entire solution set based on the density values ​​of all solution points;

[0093] S2334, continuously monitor the change of information entropy in the entire solution set;

[0094] S2335. When the information entropy value remains stable within a preset range, the battery pack status analysis is considered to be completed, the calculation is terminated in advance, and the current operating status and trend of the battery pack are obtained.

[0095] It should be explained that the system receives the status data of the battery pack, including voltage, current, temperature, etc., and then verifies and cleans these data to remove abnormal values ​​or noise to ensure data quality;

[0096] Assuming that the status data of the battery pack contains three dimensions: voltage, temperature, and SOC, these data will be mapped to a grid in a three-dimensional space, and each grid point represents a specific status combination.

[0097] The density value of each grid point is calculated using a Gaussian function, which reflects the distribution of the state combination in the battery pack. Then, the information entropy of the entire solution set is calculated using these density values. The lower the entropy value, the more concentrated the state distribution is.

[0098] The information entropy is calculated after each data update and its changes are observed. If the information entropy gradually decreases, it indicates that the state distribution of the battery pack is becoming more concentrated and mature.

[0099] If the information entropy value fluctuates within a small range for several consecutive iterations, indicating that the state of the battery pack has stabilized, the calculation is terminated in advance and the current operating status and trend of the battery pack are reported, such as whether the battery pack is in a balanced state, or whether there are problems such as overheating or overcharging.

[0100] Preferably, calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function, and calculating the information entropy of the entire solution set based on the density values ​​of all solution points includes the following steps:

[0101] S23331. Divide each data point into a corresponding hypercube structure according to the target dimension of the battery pack status data;

[0102] S23332. For each solution point, calculate the Euclidean distance between the current solution point and other solution points;

[0103] S23333. Select the Gaussian influence function as the function for measuring the influence between solution points;

[0104] S23334. For each solution point, based on the distance between the current solution point and other solution points, calculate the density value by using the Gaussian influence function;

[0105] S23335. Standardize the density values ​​of all solution points and calculate the information entropy of the entire solution set according to the Shannon entropy formula.

[0106] Preferably, the expression for calculating the density value by the Gaussian influence function is:

[0107]

[0108] In the formula, Ω(l i →y) represents the solution point l in the battery status data point i The impact on the solution point y;

[0109] l i represents the i-th solution point of the battery pack state;

[0110] y represents the yth solution point of the battery pack state;

[0111] σ represents the normal fluctuation range allowed between solution points in the battery pack state data;

[0112] e represents the base of natural logarithm;

[0113] (l i -y) 2 Indicates the solution point l in the battery status data point i The square of the Euclidean distance from the solution point y.

[0114] It should be explained that, assuming that the status data of the battery pack includes three dimensions of voltage, temperature and SOC, each data point is assigned to a specific position in a three-dimensional hypercube according to its values ​​in these three dimensions.

[0115] For each point in the hypercube, the distances to all other points are calculated. These distances reflect the relative positions of the data points in the state space.

[0116] A Gaussian function is used to measure the influence of one solution point on another solution point. The shape of the Gaussian function is similar to a bell curve, with the center point having the greatest influence and the influence gradually decreasing as the distance increases.

[0117] For each solution point, a Gaussian function is used to calculate its influence on other solution points. The higher the influence value, the greater the influence of the solution point on its surrounding solution points.

[0118] Normalize the density values ​​of all solution points so that their sum is one, and then use the Shannon entropy formula to calculate the information entropy of the entire solution set. The lower the entropy value, the more concentrated the distribution of the solution set.

[0119] Among them, the expression of Shannon entropy formula is:

[0120]

[0121] In the formula, H(X) represents the information entropy of the random variable X, that is, the degree of uncertainty of all possible states of X. The larger the entropy value, the more uncertain the system is and the more dispersed the information is.

[0122] p(x i ) indicates that the random variable X takes the i-th possible state x i The probability of

[0123] log2p(x i ) represents the battery pack status x i The probability p(x i ) Take the binary logarithm, that is, the logarithm with base 2;

[0124] n represents the total number of different possible states of the random variable X.

[0125] S24. Based on the processing result, the energy management system uses the received status information for real-time monitoring and adjusts the power output or test process of the converter control system as needed.

[0126] It should be explained that the energy management system monitors the current operating status of the battery pack by continuously receiving and processing the real-time status information (such as voltage, temperature, SOC, etc.) fed back by the battery management system. The status information reflects the health and performance indicators of the battery pack; according to the status of the battery pack, the energy management system can dynamically adjust the power output of the converter control system. For example, if the battery pack is overheated or the voltage is too high, the charging or discharging power will be reduced to prevent further damage to the battery; conversely, if the battery is in good condition, the energy management system can increase the power to speed up the test process; if the monitored status information shows that the battery pack is abnormal or has reached the preset conditions of the test, the energy management system can adjust the test process in time. For example, during the charging or discharging process, if a battery cell reaches the cut-off voltage, the round of testing will be automatically ended and the data will be saved, or the subsequent test steps will be adjusted to ensure that the test process is safe and effective.

[0127] S25. The battery management system ensures the logical interlocking and operation management of the test system, triggers safety protection measures or stops the test.

[0128] Preferably, the battery management system ensures the logic lockout and operation management of the test system, triggering safety protection measures or stopping the test includes the following steps:

[0129] S251, the battery management system monitors the key status parameters of the battery pack in real time;

[0130] S252. Perform logical judgment on each operation to ensure that all steps in the test process comply with preset safety rules;

[0131] S253. When an abnormal state is detected, the battery management system immediately triggers a preset safety protection mechanism;

[0132] S254: If the battery management system detects that the critical state reaches the emergency shutdown condition, it sends a command to stop the test immediately;

[0133] S255. After stopping the test, record all relevant status data and triggered protection measures.

[0134] It needs to be explained that the battery management system continuously monitors the key parameters of the battery pack, such as voltage, temperature, SOC (state of charge), current, etc. The key parameters are the basis for ensuring the safety and efficient operation of the battery during the test process; the battery management system uses logical judgment to ensure that each step of the test complies with the preset operating procedures to avoid any unsafe operations; for example, the system will automatically check whether all starting conditions are met before starting the test; when the battery status is detected to be abnormal (such as overtemperature, overvoltage or short circuit), the battery management system will automatically trigger the preset protection mechanism, such as powering off or starting the cooling system to prevent further damage; when the battery pack reaches the set critical state (such as the temperature exceeds the safety range or the voltage exceeds the limit), the battery management system will issue a command to stop the test immediately to ensure safety. After the test stops, the battery management system will record all status data of the battery pack and the triggered protection mechanism.

[0135] S3. Select a test mode in the energy management system according to the test requirements, and issue a power control instruction to the converter control system according to the set test process.

[0136] Preferably, the test modes include grid-connected charging, grid-connected towing, and off-grid towing.

[0137] It needs to be explained that the working modes of the energy storage battery prefabricated cabin towing test platform can be divided into three types: grid-connected charging, grid-connected towing and off-grid towing.

[0138] Grid-connected charging: In the grid-connected mode, a single energy storage battery prefabricated cabin can be charged separately. Taking the charging of the BAT1 battery cabin under test as an example, disconnect the frame circuit breaker QF2, close the isolating switch QS, and control the closing of the frame circuit breaker QF of the incoming cabinet through the host computer of the test cabinet. Control the closing of the frame circuit breaker QF1 in the junction cabinet through the host computer. The host computer software sends an operation mode control instruction (grid-connected standby) to PCS1, close the junction cabinet switch in the BAT1 battery cabin under test, and then adjust and set PCS1 to charge the BAT1 battery cabin under test in a low power (for example, 10% of the rated power) constant power charging mode. The BAT1 battery cabin under test is charged. 1 The battery compartment is charged through the power grid to improve its SOC. If the power load in the factory is large, it is necessary to charge the energy storage battery prefabricated compartment during the off-peak period. The upper computer detects that any battery cell or battery module in the BAT1 battery compartment of the tested product has reached the cut-off voltage. The upper computer controls PCS1 to return to standby mode. The front acquisition module of the test cabinet collects the charge and discharge test result data, which should include initial charging energy, charging time, initial charging energy / rated charging energy, battery cell voltage extreme difference at the end of charging, battery cell temperature extreme difference at the end of charging, battery module voltage extreme difference at the end of charging, battery cell maximum temperature rise, initial charging capacity and other data information. Then control PCS1 to shut down, and the charging method for the BAT2 battery compartment of the tested product is similar.

[0139] Grid-connected pairing: PQ control is applied to grid-connected distributed power generation or microgrid systems. In this system, the public grid system provides voltage support. In the grid-connected mode, the BAT1 battery compartment of the tested product and the BAT2 battery compartment of the tested product complete pairing. First, manually close the isolating switch QS, close the frame circuit breaker QF of the incoming cabinet through the host computer of the test cabinet, close the switch of the junction cabinet in the battery compartment of the tested product BAT2, close the frame circuit breaker QF2 of the junction cabinet, set PCS2 to standby mode through the host computer, send an instruction to set PCS2 to constant power charging mode, close the switch of the junction cabinet in the battery compartment of the tested product BAT1, close the frame circuit breaker QF1 of the junction cabinet, set PCS1 to standby mode through the host computer, send an instruction to set PCS1 to constant power discharge mode, and set the charging and discharging power to 0.1P until the host computer detects that any battery cell or battery module in the battery compartment of the tested product BAT1 reaches the cut-off voltage, the host computer controls PCS2 to return to standby mode, the host computer exports the charging and discharging test data, and the host computer sends an instruction to put PCS1 and PCS2 in standby mode. During the test, the two-way meter PM is used to monitor and prevent reverse power from being sent to the grid. If the host computer detects reverse power, it will open the frame circuit breaker QF of the incoming cabinet according to the set power limit and time through RS485 communication. After standing for half an hour, PCS1 is set to constant power charging mode and PCS2 is set to constant power discharge mode. When the battery compartment of the tested product BAT1 is charged to 30% SOC to meet the factory requirements, the host computer sends a command to put PCS2 in shutdown mode and PCS1 in shutdown mode.

[0140] Drag charging and discharging in off-grid mode: Phase 1: Before testing, ensure that the SOC of the BAT1 battery compartment and the BAT2 battery compartment of the tested product is at 30%. Disconnect the frame circuit breaker QF of the main switch of the incoming cabinet through the host computer of the test cabinet, manually disconnect the isolating switch QS in the junction cabinet, close the main switch of the junction cabinet in the BAT1 battery compartment of the tested product, establish the DC side voltage of PCS1, and check that there is no abnormality in the battery compartment data. First, send a control instruction through the host computer to set PCS1 to the constant voltage V / F working mode. After the voltage and frequency are established on the AC side without load, control the frame circuit breaker QF1 to close through the host computer, and then control the frame circuit breaker QF2 to close through the host computer. Set PCS2 to standby mode through the host computer and close the BAT2 battery compartment of the tested product. The main switch of the internal junction box is turned on, and then the control command is sent through the host computer to set PCS2 to close and work in charging mode until the host computer detects that any battery cell or battery module in the BAT1 battery compartment of the tested product has reached the cut-off voltage. The host computer controls PCS1 and PCS2 to return to standby mode. The charge and discharge test result data should include the initial discharge energy, discharge time, initial discharge energy / rated discharge energy, battery cell voltage extreme difference at the end of discharge, battery cell temperature extreme difference at the end of discharge, battery module voltage extreme difference at the end of discharge, battery cell maximum temperature rise, initial discharge capacity and other data information of the BAT1 battery compartment of the tested product. Then control PCS1 and PCS2 to shut down, and the host computer controls to disconnect the frame circuit breaker QF1 and frame circuit breaker QF2 in turn, and let it stand for 0.5 hours.

[0141] The second stage: confirm that the frame circuit breaker QF of the incoming cabinet and the isolating switch QS of the junction cabinet are in the open state, close the junction cabinet switch in the battery compartment of the tested product BAT2, establish the DC side voltage of PCS2, check the battery compartment data for abnormalities, and control the frame circuit breaker QF2 to close through the host computer of the test cabinet. First, send a control instruction through the host computer to set PCS2 in constant voltage V / F working mode to establish voltage and frequency, and then control the frame circuit breaker QF1 to close through the host computer, and set PCS1 in standby mode through the host computer to send a control instruction, close the main switch of the junction cabinet in the battery compartment of the tested product BAT1, and then send a control instruction through the host computer to set PCS1 to close and work in charging mode until the host computer detects that any battery cell or battery module in the battery compartment of the tested product BAT2 reaches the cut-off voltage. The host computer controls PCS1 and PCS2 to return to standby mode. The host computer records the test results, and then disconnects the frame circuit breakers QF1 and QF2 of the junction cabinet in turn.

[0142] The third stage: let it stand for 0.5 hours, and balance the BAT1 and BAT2 battery compartments to the 30% SOC requirement before leaving the factory according to the first stage method. The battery capacity loss during the test is charged and replenished according to the grid-connected charging mode to meet the factory requirements.

[0143] The test cabinet energy management system EMS is designed with a one-time simulation UI interface and operation log to display parameter modification records, equipment fault records, and the current status of the equipment, including the switch opening and closing status information of the incoming cabinet and the junction cabinet, and electrical parameter information, to achieve digital management and control of the test process. After the test, the test results can be automatically exported to avoid time-consuming and error-prone manual recording, which is more efficient.

[0144] S4. After receiving the power control command from the energy management system, the converter control system controls the energy storage battery prefabricated cabin to perform charging and discharging tests according to the power curve information. At the same time, the energy management system monitors the test process in real time.

[0145] It should be explained that the converter control system will receive specific power control instructions from the energy management system. The power control instructions include setting the power size, duration, and other parameters of charging or discharging; the converter control system performs operations based on the power curve information. The power curve is usually pre-set and specifies the charging and discharging power of the energy storage battery during the entire test process. The system adjusts the charging or discharging power according to different test requirements. For example, constant power charging may be required, or dynamically changing power output may be required to simulate real usage scenarios; the energy storage battery prefabricated cabin starts charging or discharging according to the instructions of the converter control system. During this process, the battery management system is responsible for monitoring the key status of the battery (such as voltage, temperature, SOC, etc.) to ensure that the test is carried out within a safe range; during the charge and discharge test, the energy management system will continuously monitor the status information of the battery pack and compare this information with the preset test conditions. If an abnormality is detected or the status reaches the test cutoff condition (such as the battery cell reaches the maximum voltage or temperature), the energy management system can adjust the test process or terminate the test in time to ensure safety.

[0146] S5. When the battery pack reaches the set cut-off state, the energy management system immediately sends a zero power command to the converter control system, terminates the test, exports the test results and generates a test report.

[0147] The specific examples are as follows: charging and discharging test of prefabricated energy storage battery cabin.

[0148] In a battery energy storage system project, the engineering team needs to conduct comprehensive tests on the charging and discharging performance of two prefabricated energy storage battery cabins (each prefabricated cabin contains multiple battery packs) to ensure that they can work stably and meet the technical requirements of the project.

[0149] 1) Test objectives:

[0150] Test the charging and discharging capabilities of two energy storage battery prefabricated cabins under different power output conditions.

[0151] Verify the response performance of the battery pack of the prefabricated cabin under normal operation and emergency conditions.

[0152] Collect battery status data to evaluate the overall health of the battery (including voltage, temperature, SOC, etc.).

[0153] 2) Test preparation:

[0154] Power on and self-test of test equipment: Before the test begins, the system engineer first powers on all equipment in the test platform and ensures that the equipment is in normal condition. The incoming line cabinet, junction cabinet, energy storage battery prefabricated cabin and energy management system (EMS) establish communication connections. After completing the self-test, the test officially begins.

[0155] Real-time status monitoring is established: After completing the self-test, the battery management systems (BMS) of the two energy storage battery prefabricated cabins begin to send real-time status information (including the voltage, temperature and SOC of each battery module, etc.) to the energy management system EMS and converter control system (PCS) for monitoring and adjustment during the test process.

[0156] 3) Select the grid-connected charging test mode:

[0157] According to the current test requirements, EMS selected the "grid-connected charging" mode and planned to charge the energy storage battery prefabricated cabin 1. The system engineer set a low-power charging mode, with the goal of increasing the SOC of the battery pack from the current 30% to 80%.

[0158] Charging operation: After receiving the power control command from the EMS, the converter control system (PCS1) starts charging the energy storage battery prefabricated cabin 1 at the set power of 10kW. During the charging process, the EMS continuously collects the real-time status data of the battery pack (such as voltage, temperature, SOC, etc.) through the BMS, and analyzes and processes the data.

[0159] For example, when the battery pack temperature rises to the critical point of the safety threshold, the EMS will immediately issue an alarm and notify the PCS to reduce the charging power to avoid overheating damage.

[0160] Grid-connected towing test: While the energy storage battery prefabricated cabin 1 is being charged, the energy storage battery prefabricated cabin 2 enters the "grid-connected towing" test mode. At this time, the energy storage battery prefabricated cabin 2 starts to charge the energy storage battery prefabricated cabin 1 at 0.1P power. During the whole process, the EMS continuously monitors the voltage, SOC, temperature and other status parameters of the two prefabricated cabins.

[0161] During the discharge process, when EMS detects that the voltage of some cells in the energy storage battery prefabricated compartment 2 is close to the safety lower limit, EMS will promptly notify PCS2 to reduce the discharge power or suspend the discharge operation.

[0162] Off-grid mode test: The test also includes an off-grid towing mode, simulating the coordinated charging and discharging of two battery prefabricated cabins without an external power grid. The EMS issues a command to put the converter control system (PCS1) in voltage-frequency mode (V / F), and then sends a control command to set the converter control system (PCS2) to work in charging mode, while the energy storage battery prefabricated cabin 2 is charged at the set power. The entire process is coordinated by the EMS and PCS to ensure that the battery status is stable and no abnormalities occur.

[0163] 4) Test termination and data processing:

[0164] Termination test: When any battery cell or battery module in the energy storage battery prefabricated compartment 1 reaches the cut-off voltage and meets the test termination conditions, the EMS issues a command to stop charging and controls PCS1 and PCS2 to return to standby mode.

[0165] Data collection and report generation: After the test is completed, EMS automatically collects all key data during the test, including: initial discharge energy, discharge time, initial discharge energy / rated discharge energy, battery cell voltage extreme difference at the end of discharge, battery cell temperature extreme difference at the end of discharge, battery module voltage extreme difference at the end of discharge, battery cell maximum temperature rise, initial discharge capacity, and battery voltage changes during charging and discharging; battery pack temperature trend; SOC changes of each battery cell; power output fluctuations, etc.

[0166] The data was processed and a detailed test report was generated, which included key information such as charge and discharge performance evaluation, temperature control effect, power control accuracy, etc., providing an important basis for performance evaluation and troubleshooting of the battery system.

[0167] 5) Test results and analysis:

[0168] During the test, the EMS and PCS systems were able to stably coordinate the charging and discharging process of the battery prefabricated compartment, and no abnormalities occurred in any mode.

[0169] The temperature rise of the battery pack during charging and discharging remained within a reasonable range and did not exceed the specified safety threshold, indicating that the heat dissipation system is effective.

[0170] The test report shows that the changes in the SOC of the two prefabricated cabins in different modes are consistent with expectations, verifying the overall stability and safety of the energy storage system.

[0171] According to another embodiment of the present invention, Figure 2As shown, a test platform for a towing test of a prefabricated energy storage battery cabin is also provided. The test equipment in the test platform for the towing test of a prefabricated energy storage battery cabin includes a test equipment, and the test equipment includes a frame base 1, and a test cabinet 2, an incoming line cabinet 3, a junction cabinet 4, an isolation transformer cabinet 5, a first converter control system module 6 and a second converter control system module 7 are sequentially arranged on the surface of the frame base 1.

[0172] In addition, it is necessary to explain that Figure 3 As shown in the figure (S represents the integral controller of the complex function), the microgrid system is a small power grid composed of various micro sources, energy storage devices, loads, protection and monitoring devices, etc., which can realize self-control, protection and management; it has flexible operation mode and dispatching management performance, and can be integrated into the large power grid for operation, and can also operate independently in an isolated island; in the networked mode, it shares the power supply demand of users with the large power grid, and in the isolated island mode, it guarantees the normal power consumption of users, especially important users. The energy storage converter PCS in the microgrid system generally adopts different control strategies according to different operation modes. In the grid-connected operation mode, in order to facilitate unified dispatching, the energy storage converter generally adopts active to reactive (i.e. PQ) control; in the off-grid mode, in order to support the voltage and frequency in the microgrid isolated island mode, constant voltage / frequency (i.e. V / F) control is generally adopted. In the voltage / frequency control mode, the PCS module automatically adjusts the power output according to the closed-loop control of the AC voltage and frequency.

[0173] Reference frequency f ref The phase θ of the reference voltage is calculated and obtained in real time through the proportional and integral amplifiers, and is transmitted to the reference voltage converter and the reference current converter respectively; the grid-side voltage converter and the grid-side current converter are both abc / dq converters, which are used to convert the three AC components a, b and c into two DC components d and q; the grid-side voltage converter calculates the d-axis component u of the sampled voltage according to the collected sampled voltage and the phase θ of the transmitted reference voltage od and the q-axis component u oq ; The d-axis component u of the sampled voltage od and the q-axis component u oq And the reference voltage u dref and u qref After the voltage outer loop is calculated, it is converted into a reference current i dref and i qref The grid-side current converter calculates the d-axis component i of the sampling current according to the collected sampling current and the phase θ of the transmitted reference voltage. Ld and the q-axis component i Lq ; The d-axis component i of the sampling current Ld and the q-axis component i Lq And the reference current i dref and i qrefIt is converted into a reference voltage through the current inner loop; the reference voltage and its phase are converted into a dq / abc converter through the reverse coordinate converter, which is used to convert the two DC components d and q into AC voltage and transmit it to the SVPWM generator, and finally control the power switch control loop of the power grid to realize PWM control on and off, thereby achieving the constant power control purpose of PCS.

[0174] The implementation method is as follows:

[0175] The test platform for the towing test of the energy storage battery prefabricated cabin described in the present invention is mainly composed of a frame base 1, an incoming line cabinet 3, a junction cabinet 4, an isolation transformer cabinet 5, a converter PCS, a test cabinet 2, cable auxiliary materials, etc. The various devices are modularly assembled on the frame base, which has a compact size and a core-pulling hanging column on the base, which is flexible to transport and easy to turn around. Electrically, the 0.4kV distribution network of the plant area is connected to the 0.4kV side of the isolation transformer TR through the incoming cabinet frame circuit breaker QF. The isolation transformer TR boosts the 0.4kV voltage to 0.69kV and inputs it to the junction cabinet. The incoming line of the junction cabinet is the isolating switch QS. The isolating switch QS is divided into two feeder frame circuit breakers QF1 and QF2 from the lower pile head to the busbar. Each frame circuit breaker is connected to the corresponding AC side of the current transformer PCS1 and PCS2. The DC side of each PCS can receive the tested product BAT1 battery compartment and the tested product BAT2 battery compartment of the energy storage battery prefabricated cabin. The primary system diagram of the test platform is as follows: Figure 4 As shown in the figure (TA represents current transformer), the battery management system BMS of the battery compartment plays a sensing role, which is mainly responsible for battery monitoring, evaluation, protection and balancing; the test system EMS plays a decision-making role, which is mainly responsible for data collection and forwarding, network monitoring and energy scheduling; the energy storage converter PCS plays an execution role, whose main function is to control the charging and discharging process of the energy storage battery pack and perform AC / DC conversion.

[0176] To sum up, with the help of the above technical scheme of the present invention, the entire test platform in the present invention is prefabricated in the factory, with compact size, small footprint, modular assembly, flexible and fast transportation, and can be towed away, effectively solving the problems of complex and cumbersome equipment and difficult experimental environment construction during battery pack performance evaluation; the test platform can meet multiple charging and discharging modes such as grid-connected charging, grid-connected towing, and off-grid towing, with integrated functions, material saving, and improved battery performance evaluation efficiency; the host computer of the test cabinet can collect power information of the bidirectional metering multifunctional meter of the incoming cabinet, and control the incoming cabinet circuit breaker to trip the incoming circuit breaker according to the set reverse power threshold and delay time when reverse power is detected to prevent reverse power transmission; the test cabinet energy management system EMS can communicate with the converter PCS and the battery prefabricated cabin BMS, and set the test plan according to the test plan. The program automatically sends instructions for charge and discharge tests (the rate and cutoff conditions can be set) and mode conversion, with a high degree of automatic testing to avoid repeated manual settings. The present invention divides the data into multi-dimensional grids and uses Gaussian influence functions to calculate the solution point density, so as to accurately describe the distribution of the battery pack state in the multi-dimensional space. Through the calculation of information entropy, the changes in the battery pack state distribution can be effectively tracked, and the operating trend of the battery pack can be identified. Based on the real-time analysis results of the battery pack state data, the energy management system can dynamically adjust the power output and other parameters of the inverter control system, and use Gaussian influence functions and information entropy to measure the concentration of the battery pack state distribution. In the processing and trend analysis of multi-dimensional data, abnormal battery conditions can be identified earlier, such as risk factors such as overheating and overcharging.

[0177] Although the present invention has been disclosed as above with preferred embodiments, the embodiments are merely examples for the convenience of description and are not intended to limit the present invention. Those skilled in the art may make several changes and modifications without departing from the spirit and scope of the present invention. The scope of protection claimed by the present invention shall be based on the claims.

Claims

1. A test method for towing test of energy storage battery prefabricated cabin, characterized in that: include: S1. Power on the test equipment on the test platform to ensure that each device is in normal condition and completes self-test; S2, the battery pack in the energy storage battery prefabricated cabin starts to send real-time status information, and feeds back the real-time status information to the energy management system and the converter control system through the battery management system; S3. Selecting a test mode in the energy management system according to the test requirements, and issuing a power control instruction to the converter control system according to the set test process; S4. After receiving the power control command from the energy management system, the converter control system controls the energy storage battery prefabricated cabin to perform charging and discharging tests according to the power curve information, and the energy management system monitors the test process in real time; S5. When the battery pack reaches the set cut-off state, the energy management system immediately sends a zero power command to the converter control system, terminates the test, exports the test results and generates a test report; Wherein, the S2 includes: S23, the energy management system and the converter control system receive the real-time status information from the battery management system and process the real-time status information; S24. Based on the processing result, the energy management system uses the received status information to perform real-time monitoring and adjusts the power output or test process of the converter control system as needed; S25, the battery management system ensures the logic interlocking and operation management of the test system, triggers safety protection measures or stops the test; The S23 includes: S233, the energy management system analyzes the parsed key status data to identify the current operating status and trend of the battery pack; S234. According to the analysis results and the preset control logic, the energy management system generates and issues control instructions to adjust the power output of the converter control system; The S233 includes: S2331, analyzing and cleaning key status data of the battery pack; S2332, dividing the battery pack status data after cleaning into grids according to multiple target dimensions, and creating a corresponding hypercube structure; S2333, calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function, and calculating the information entropy of the entire solution set based on the density values ​​of all solution points; S2334, continuously monitor the change of information entropy in the entire solution set; S2335. When the information entropy value remains stable within a preset range, the battery pack status analysis is considered to be completed, the calculation is terminated in advance, and the current operating status and trend of the battery pack are obtained.

2. A test method for towing test of energy storage battery prefabricated cabin according to claim 1, characterized in that: The step of powering on the test equipment to ensure that each device is in a normal state and completes the self-test includes the following steps: S11. Power on the test equipment to ensure that each device is in a normal state, and connect the frame circuit breakers in the incoming cabinet and the combiner cabinet to the energy management system of the test cabinet through the communication interface; S12, after the communication signal passes through the protocol conversion device, it is connected to the energy management system through the switch; S13, the converter control system and the battery management system of the energy storage battery prefabricated cabin are connected to the energy management system.

3. A test method for towing test of energy storage battery prefabricated cabin according to claim 2, characterized in that: The energy management system and the converter control system receive the real-time status information from the battery management system, and before processing the real-time status information, the process also includes: S21, starting the battery management system in the energy storage battery prefabricated cabin, and establishing a communication connection with the energy management system and the converter control system; S22. Collect the real-time status information of the battery pack using the battery management system, and send it to the energy management system and the converter control system through the communication connection.

4. A test method for towing test of energy storage battery prefabricated cabin according to claim 3, characterized in that: The energy management system analyzes the parsed key status data and identifies the current operating status and trend of the battery pack, and further includes: S231, the energy management system and the converter control system receive real-time status information data sent by the battery management system through a predetermined communication interface; S232: The received real-time status information data is parsed by the protocol parsing module inside the energy management system and the converter control system, and key status data of the battery pack is extracted.

5. A test method for towing test of energy storage battery prefabricated cabin according to claim 4, characterized in that: The method of calculating the density value of each solution point in the hypercube structure by using the Gaussian influence function and calculating the information entropy of the entire solution set based on the density values ​​of all solution points includes the following steps: S23331. Divide each data point into a corresponding hypercube structure according to the target dimension of the battery pack status data; S23332. For each solution point, calculate the Euclidean distance between the current solution point and other solution points; S23333. Select the Gaussian influence function as the function for measuring the influence between solution points; S23334. For each solution point, based on the distance between the current solution point and other solution points, calculate the density value by using the Gaussian influence function; S23335. Standardize the density values ​​of all solution points and calculate the information entropy of the entire solution set according to the Shannon entropy formula.

6. A test method for towing test of energy storage battery prefabricated cabin according to claim 5, characterized in that: The expression for calculating the density value by Gaussian influence function is: In the formula, Ω(l i →y) represents the solution point l in the battery status data point i The impact on the solution point y; l i represents the i-th solution point of the battery pack state; y represents the yth solution point of the battery pack state; σ represents the normal fluctuation range allowed between solution points in the battery pack state data; e represents the base of natural logarithm; (l i -y) 2 Indicates the solution point l in the battery status data point i The square of the Euclidean distance from the solution point y.

7. A test method for towing test of energy storage battery prefabricated cabin according to claim 6, characterized in that: The battery management system ensures the logic locking and operation management of the test system, triggers safety protection measures or stops the test, including the following steps: S251, the battery management system monitors the key status parameters of the battery pack in real time; S252. Perform logical judgment on each operation to ensure that all steps in the test process comply with preset safety rules; S253. When an abnormal state is detected, the battery management system immediately triggers a preset safety protection mechanism; S254: If the battery management system detects that the critical state reaches the emergency shutdown condition, it sends a command to stop the test immediately; S255. After stopping the test, record all relevant status data and triggered protection measures.

8. The test method for towing test of energy storage battery prefabricated cabin according to claim 1 is characterized in that: The test modes include grid-connected charging, grid-connected towing, and off-grid towing.

9. A test platform for towing test of energy storage battery prefabricated cabin, characterized in that: The test platform for the towing test of the prefabricated energy storage battery cabin includes a test device, and the test device is composed of a frame base, a test cabinet, an incoming line cabinet, a junction cabinet, an isolation transformer cabinet, a first inverter control system module and a second inverter control system module, and is used to execute the steps of the test method for the towing test of the prefabricated energy storage battery cabin described in any one of claims 1-8.

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