Intelligent management and protection system, method and equipment for photovoltaic energy storage battery

Abstract

The invention provides an intelligent management and protection system, method and equipment for a photovoltaic energy storage battery, and relates to the technical field of photovoltaic energy storage systems, operation data are collected and transmitted in real time through a remote maintenance module depending on an inverter communication module, the state of the battery can be mastered without on-site inspection, and the operation and maintenance cost and the human input are greatly reduced; the charging control module dynamically judges the charging state based on the operation data, and accurately regulates and controls the charging process in combination with the deviation degree of the operation state, so that the charging efficiency of the healthy battery is prevented from being influenced by excessive control, and the aging battery is prevented from being aggravated and attenuated due to disordered charging; when an island signal is detected by the island protection module, the power grid connection can be quickly cut off to guarantee the safety of the power grid and maintenance personnel, and the inverter can be linked to enable the battery to enter an off-grid mode to continuously supply power, so that the power supply reliability and the emergency guarantee capability of the photovoltaic energy storage system are comprehensively improved, and the intelligence and the safety of battery management are integrally realized.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic energy storage system technology, and in particular to an intelligent management and protection system, method and equipment for photovoltaic energy storage batteries. Background Technology

[0002] In the field of photovoltaic energy storage battery charging control, existing control processes mostly follow a fixed pattern. First, basic data such as the output voltage and current of the photovoltaic array and the voltage and current at the battery terminals are collected by sensors. Then, according to the preset charging stage division, such as constant current charging stage and constant voltage charging stage, the collected data is compared with the set threshold for each stage. If it is in the constant current charging stage, the battery is charged with a constant current when the battery voltage has not reached the switching threshold; once the voltage approaches the threshold, it switches to the constant voltage charging stage, maintaining a constant voltage, and the current gradually decreases as the battery charges.

[0003] For example, Chinese invention patent CN118971301B discloses a battery charging control method, energy storage device, and photovoltaic energy storage system. The method includes: when the battery is in a float charging state, acquiring the battery's actual charging voltage, actual charging current, actual charging power, and actual power generation voltage of the power generation module; obtaining a first adjustment parameter based on the actual charging voltage, the battery's preset float charging voltage, and the actual charging current; obtaining a second adjustment parameter based on the actual charging power and the battery's maximum charging power; obtaining a target power generation voltage of the power generation module based on the first adjustment parameter, the second adjustment parameter, and the actual power generation voltage of the power generation module; and adjusting the actual power generation voltage of the power generation module based on the target power generation voltage to stabilize the battery's float charging state.

[0004] For example, Chinese invention patent CN103138347B discloses a charging control method for a photovoltaic charging controller. By determining the required charging mode of the battery energy storage system, the corresponding control algorithm is used to obtain the input voltage command according to different charging modes. Then, through dual closed-loop control of input voltage and output current and feedforward control, accurate and fast control of each charging mode is achieved.

[0005] The existing technology has the following technical problems:

[0006] In photovoltaic (PV) energy storage battery charging control technology, while existing solutions consider normal battery aging and set corresponding charging strategies, battery aging is a complex and non-linear process in actual operation. Besides being affected by conventional factors such as cycle count and usage duration, it is also closely related to the actual operating state of the PV energy storage battery. Existing technologies mostly set charging parameters based on idealized aging models, making it difficult to accurately match the actual aging state of the battery. When a battery ages beyond expectations due to complex operating conditions, its internal resistance, capacity, and other characteristic parameters change irregularly. Existing control technologies cannot detect and dynamically adjust the charging strategy in a timely manner, leading to abnormal current and voltage control during charging. This can result in problems such as overcharging damaging the battery's active materials and over-discharging affecting the battery's cycle life, severely impacting the performance and reliability of the PV energy storage system. Summary of the Invention

[0007] To address the technical problem of accurately matching the actual aging state of batteries in existing technologies, embodiments of the present invention provide an intelligent management and protection system, method, and device for photovoltaic energy storage batteries. The technical solution is as follows:

[0008] On the one hand, an intelligent management and protection system for photovoltaic energy storage batteries is provided. This system includes: a remote maintenance module, used to collect the operating data of the photovoltaic energy storage battery through the communication module built into the inverter and transmit it remotely, thereby monitoring the operating status of the photovoltaic energy storage battery in real time; a charging control module, used to determine whether the photovoltaic energy storage battery is in a charging state based on the operating data of the photovoltaic energy storage battery. If so, it analyzes the degree of deviation of the operating state of the photovoltaic energy storage battery to determine whether to intelligently control and manage the charging process of the photovoltaic energy storage battery. If not, it continuously collects the operating data of the photovoltaic energy storage battery; and an islanding protection module, used to implement islanding protection when an islanding signal is detected. At the same time, the photovoltaic energy storage battery, together with the inverter, enters off-grid mode to continuously supply power to the local load.

[0009] On the other hand, a method for intelligent management and protection of photovoltaic energy storage batteries is provided. This method includes: collecting the operating data of the photovoltaic energy storage battery through the communication module built into the inverter and transmitting it remotely to monitor the operating status of the photovoltaic energy storage battery in real time; based on the operating data of the photovoltaic energy storage battery, determining whether the photovoltaic energy storage battery is in a charging state; if so, analyzing the degree of deviation of the operating state of the photovoltaic energy storage battery to determine whether to intelligently control and manage the charging process of the photovoltaic energy storage battery; if not, continuously collecting the operating data of the photovoltaic energy storage battery; when an islanding signal is detected, islanding protection is implemented, and the photovoltaic energy storage battery, together with the inverter, enters off-grid mode to continuously supply power to the local load.

[0010] On the other hand, an intelligent management and protection device for photovoltaic energy storage batteries is provided. The device includes: a processor; a transceiver; and a memory. The memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, an intelligent management and protection system for photovoltaic energy storage batteries is realized.

[0011] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0012] (1) The present invention uses the remote maintenance module to collect and transmit operating data in real time through the inverter communication module, so that the battery status can be grasped without on-site inspection, which greatly reduces the operation and maintenance cost and manpower input, and at the same time realizes the timely capture of abnormal data; the charging control module dynamically judges the charging status based on the operating data, and accurately controls the charging process in combination with the degree of deviation of the operating status, which can not only avoid the healthy battery from being affected by excessive control, but also prevent the aging battery from being accelerated by disordered charging, thus extending the overall battery life; when the islanding protection module detects the islanding signal, it can not only quickly disconnect the grid connection to ensure the safety of the grid and maintenance personnel, but also link the inverter to allow the battery to enter the off-grid mode to continue to supply power, thus avoiding the interruption of local critical loads (such as home emergency equipment and small medical instruments) due to grid power failure, improving the power supply reliability and emergency protection capability of the photovoltaic energy storage system, and realizing the intelligent and safe battery management as a whole.

[0013] (2) When the pre-charge closing strategy is implemented, the present invention can quickly identify voltage abnormalities by monitoring the DC bus voltage rise rate in real time and comparing it with the reference range, and promptly limit the charging and discharging current and upload the status to the cloud platform to avoid abnormal voltage impacts that accelerate battery plate damage or electrolyte decomposition, thereby reducing unnecessary aging from the source. When the voltage rise rate is normal, the reference internal resistance range is accurately matched by dynamically adjusting the actual internal resistance and the abnormal operation index. This can not only avoid sudden aging damage caused by short circuits through low internal resistance warning, but also prevent high temperature or overload from further aggravating capacity decay and internal resistance increase in the case of high internal resistance (abnormal aging) by tightening the temperature working window and reducing the load. Overall, it not only lays a solid safety foundation for the subsequent constant current and constant voltage charging stages, but also effectively delays the overall aging process of the battery and extends its cycle life by intervening in the aging risk in the pre-charge stage, ensuring the safety and reliability of the photovoltaic energy storage battery in long-term operation.

[0014] (3) In the constant current stage, the present invention steadily increases the current at the corrected current change rate and dynamically reduces the rate when the battery is abnormally aging. This can avoid the sudden increase of current causing additional impact on the electrode structure of the aging battery and reduce the capacity decay caused by the intensification of polarization. When an abnormality is detected, the rate is temporarily reduced to avoid the risk of over-limit in advance and prevent irreversible damage to the aging battery caused by a single abnormality. In the float charging stage, the tail current judgment standard is improved and the judgment time is shortened for abnormally aging batteries. This can avoid electrolyte decomposition and positive electrode material structure deterioration caused by long-term high potential retention of aging batteries and slow down the aging process. At the same time, the target voltage and tail current are dynamically corrected by the deviation factor to ensure that the aging battery is in a suitable charging condition at each stage. This not only ensures charging safety but also effectively slows down the overall abnormal aging speed and extends the effective cycle life of the photovoltaic energy storage battery. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a structural diagram of an intelligent management and protection system for photovoltaic energy storage batteries provided in an embodiment of the present invention;

[0017] Figure 2 This is a flowchart of an intelligent management and protection method for photovoltaic energy storage batteries provided in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of an intelligent management and protection device for photovoltaic energy storage batteries provided in an embodiment of the present invention;

[0019] Figure 4 This is a circuit diagram of the battery float charging interface provided in an embodiment of the present invention;

[0020] Figure 5 This is a circuit diagram for anti-islanding three-phase power grid sampling and zero-crossing detection provided in an embodiment of the present invention;

[0021] Figure 6 This is a circuit diagram of the grid-connected three-phase isolation and sampling interface provided in an embodiment of the present invention;

[0022] Figure 7 This is a circuit diagram of an isolated CAN communication interface provided in an embodiment of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0024] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0025] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0026] This invention provides an intelligent management and protection system for photovoltaic energy storage batteries. For example... Figure 1 The diagram shows a structure of an intelligent management and protection system for photovoltaic energy storage batteries. The system may include the following modules: a remote maintenance module, a charging control module, an islanding protection module, and a database.

[0027] The database is used to store parameters involved in an intelligent management and protection system for photovoltaic energy storage batteries.

[0028] The remote maintenance module is connected to the charging control module and the islanding protection module. The charging control module is connected to the islanding protection module. The remote maintenance module, the charging control module, and the islanding protection module are all connected to the database.

[0029] The remote maintenance module is used to collect the operating data of the photovoltaic energy storage battery through the inverter's built-in communication module and transmit it remotely, thereby monitoring the operating status of the photovoltaic energy storage battery in real time.

[0030] The data recording mechanism of photovoltaic energy storage batteries is essentially to store key parameters such as current and voltage during the charging and discharging process in a time sequence. That is, it continuously retains the operating status information at each moment in time. Therefore, the historical operating value of the battery at the corresponding time point can be extracted by retrieving the stored data of historical time periods.

[0031] Remote control, fault diagnosis, and early warning of photovoltaic energy storage batteries mainly involve the following aspects: data acquisition and monitoring, remote control, fault diagnosis and maintenance, intelligent optimization, and data analysis. Data acquisition and monitoring: The inverter's built-in communication module includes a Wi-Fi stick, Wi-Fi communication circuit, CAN communication circuit, and communication protocol. The Wi-Fi stick and Wi-Fi communication circuit are responsible for wireless data transmission, while the CAN communication circuit is responsible for battery status monitoring and control. The communication protocol defines the data transmission format and rules. Remote data transmission specifically involves standardizing the photovoltaic energy storage battery's operating data before transmitting it to a cloud platform or monitoring center via Wi-Fi communication. During real-time monitoring of the photovoltaic energy storage battery's operating status, remote control, fault diagnosis, and early warning can also be performed. Remote Control: 1. Remote Operation: Users can operate the battery system via remote control software. Remote control functions include system start / stop, operating status switching, grid-connected charging / discharging, and off-grid discharging. 2. Intelligent Optimization: The inverter is equipped with intelligent optimization functions, automatically adjusting charging / discharging strategies according to grid peak and off-peak periods to maximize the utilization of the energy storage system's capacity, reduce electricity costs, and improve system efficiency. Fault Diagnosis and Maintenance: 1. Fault Monitoring and Alarm: The inverter can monitor abnormal phenomena during system operation and issue timely alarms. Alarm thresholds and rules can be set to analyze the operating status of the photovoltaic energy storage battery. When equipment malfunctions or data exceeds the threshold, automatic warnings are issued. 2. Remote Diagnosis and Maintenance: Engineers can perform fault diagnosis and maintenance on the equipment through a remote maintenance system, reducing equipment downtime and safety hazards. This includes fault location, parameter adjustment, firmware upgrades, etc.; Intelligent optimization and data analysis: 1. Data analysis: Real-time and historical data of power generation and energy storage systems are analyzed to generate corresponding reports and statements, providing data support for managers' decision-making, including power generation reports, charging status, electricity consumption curves, etc.; 2. Intelligent application: Continuously accumulate operational data to optimize the charging and discharging strategies of energy storage systems and improve economic efficiency.

[0032] Figure 7This is a circuit diagram of an isolated CAN communication interface provided in an embodiment of the present invention. The circuit uses an isolated CAN transceiver as its core. The CANH / CANL on the isolated side of the transceiver first undergoes common-mode noise suppression via a common-mode choke, and then a bus protection array provides surge protection for CANH / CANL relative to ground (or to an equipotential reference). Subsequently, CANH / CANL is led out through terminals / sockets. In terms of connection, the left side is the digital side; the right side is the bus side. In remote maintenance scenarios for photovoltaic energy storage batteries, this circuit is used to stably and interference-resistantly deliver BMS / PCS diagnostic, log, parameter, and firmware upgrade traffic to external maintenance terminals or gateways. The isolation layer cuts off the ground loop and common-mode displacement between the high-voltage battery ground and the control ground, protecting the main controller from lightning strikes, relay activation spikes, and long-line conducted interference. The common-mode choke and TVS ensure that CAN anti-interference and bit error rate indicators are maintained even under harsh environments such as grid-connected transients, charge / discharge switching, and overall EMI.

[0033] The islanding protection module is used to provide islanding protection when an islanding signal is detected. Simultaneously, the photovoltaic energy storage battery, in conjunction with the inverter, enters off-grid mode to continuously supply power to local loads. Islanding protection is a crucial measure to ensure the safe operation of the power grid and energy storage system. Islanding refers to the independent power supply area formed by the energy storage system and local loads when the grid experiences a power outage. The goal of anti-islanding protection is to quickly disconnect the energy storage system from the grid upon detecting a power outage, preventing the islanding effect from occurring.

[0034] Furthermore, islanding protection is achieved through the following process: Islanding effects are detected using detection algorithms, including but not limited to voltage and frequency detection algorithms and power balance detection algorithms. If islanding occurs (i.e., an islanding signal is detected), the high-speed controller and the photovoltaic energy storage battery work together to first disconnect the photovoltaic energy storage battery from the grid and issue a warning signal to achieve islanding protection. Simultaneously, the photovoltaic energy storage battery, in conjunction with the inverter, enters off-grid mode, disconnecting from the grid to continuously supply power to the local load. If islanding does not occur (i.e., no islanding signal is detected), the detection algorithm continuously monitors for islanding effects.

[0035] The system acquires grid voltage and frequency signals through voltage and frequency monitoring circuits to determine if they are within the normal range. It also acquires grid frequency signals to determine if they are within the normal range. A power monitoring circuit acquires the output current and voltage of the energy storage system and calculates the output power. Voltage and frequency detection algorithms are used to set normal ranges for voltage and frequency; if either exceeds the normal range, islanding protection is triggered. A power balance detection algorithm detects the balance between the energy storage system's output power and the load power; if an imbalance is detected, islanding protection is triggered. A trigger control strategy disconnects the system from the grid. This strategy includes: active detection, where the inverter injects a small signal into the grid and detects the feedback signal to determine the grid status; if a grid power outage is detected, the connection to the grid is immediately disconnected; and passive detection, which monitors voltage and frequency changes to determine the grid status; if an abnormal voltage or frequency is detected, the connection to the grid is immediately disconnected. After the grid returns to normal, the energy storage system is reconnected to the grid. The core technologies include: 1. High-precision sensors: Employing high-precision voltage and current sensors to ensure the accuracy of monitoring data, and using high-precision frequency counters or phase-locked loop circuits to ensure the accuracy of frequency detection; 2. Fast-response control: Employing high-speed controllers (such as DSPs or FPGAs) to ensure a rapid response upon detecting islanding effects, disconnecting the energy storage system from the grid; 3. Intelligent algorithms: Combining multiple detection methods (active and passive detection) to improve detection coverage and reliability.

[0036] Figure 5This is a circuit diagram for anti-islanding three-phase power grid sampling and zero-crossing detection provided in an embodiment of the present invention. The circuit first attenuates the U / V / W phase voltages (U_GRID, V_GRID, W_GRID) of the three-phase power grid to a safe voltage through safety voltage divider and RC filter. Then, it uses 1.65V (+1.65V_GRID, half of 3.3V) as the midpoint bias and performs follower / low-pass buffering by TLV9062 operational amplifier to obtain a proportional low-voltage waveform with 1.65V as the DC center. The buffered signal of each phase is sent to a pair of anti-parallel diodes for clamping (D13 / D14 / D15 in the figure form a clamping channel with 3.3V / GND) through a current-limiting resistor to limit the AC swing to the common-mode range allowed by the comparator and absorb spikes. Then, it enters the LM2901 four-channel comparator to perform zero-crossing comparison with 1.65V bus as reference, and outputs open-drain square wave signals U / V / W_GRID_ZERO (each channel is pulled up to 3.3V). (with small RC debouncing), providing MCU / FPGA / DSP with phase-locked loop and anti-islanding criteria. In photovoltaic energy storage anti-islanding protection, this module completes the three-phase fundamental frequency synchronization front-end from high voltage to low voltage to digital. On the one hand, it provides clean zero-crossing edges and phase information, which is convenient for passive under / overvoltage, under / overfrequency, phase jump and ROCOF (df / dt) detection, as well as response discrimination after active methods (such as frequency disturbance / reactive power disturbance). On the other hand, through pre-stage bias and diode clamping, it ensures that the comparator input is not overvoltage, common mode does not cross the limit, and surge and high-frequency switching ripple will not trigger falsely. Therefore, when the grid loses power, phase is lost, frequency drifts or impedance changes (forming islands), the period / phase / duty of U / V / W_GRID_ZERO will immediately become abnormal. The controller can quickly determine and disconnect the grid-connected inverter based on this, improving the reliability and anti-interference margin of the anti-islanding action.

[0037] Figure 6 This is a circuit diagram of the grid-connected three-phase isolation and sampling interface provided in an embodiment of the present invention. In the diagram, the three-phase grid U / V / W enters from the left and first passes through a set of parallel-pole main relays / contactors (upper part) to form the first-level physical disconnection. Then, the high-voltage side voltage is isolated and coupled to the low-voltage side through the three-phase isolation transformer in the middle. The three-phase signal of the transformer secondary is rectified by a full-bridge rectifier and shaped by a small RC network on the right side and output to the control board as a hardware criterion for the presence / phase / frequency of the grid. It also drives the grid connection indicator / status detection. The small light symbol is the grid connection indicator. The lower part of the structure corresponds to the upper part, forming the second-level series disconnection (double disconnection). Its coil is powered by the small drive unit in the lower left corner and controlled by the logic of the control board. When an anti-islanding judgment occurs, the two-level relays are released simultaneously to form a double redundant electrical isolation that meets the grid connection standard. The overall connection relationship can be understood as grid to first-level contactor to isolation sampling transformer to second-level contactor to grid connection end.

[0038] The charging control module is used to determine whether the photovoltaic energy storage battery is in a charging state based on the operating data of the photovoltaic energy storage battery. If it is, it analyzes the degree of deviation of the operating state of the photovoltaic energy storage battery to determine whether to carry out intelligent control and management of the charging process of the photovoltaic energy storage battery. If it is not, it continuously collects the operating data of the photovoltaic energy storage battery.

[0039] Specifically, the determination of whether to implement intelligent control and management of the photovoltaic energy storage battery charging process is as follows: The photovoltaic side sends energy to the DC bus via the controller and executes a pre-charge closing strategy; the DC power generated by the photovoltaic module (photovoltaic side) is transmitted to the system's DC bus (the common line for DC power collection and distribution) after maximum power point tracking and voltage regulation by the photovoltaic controller (such as an MPPT controller), providing the power foundation for subsequent charging of the energy storage battery or direct supply to DC loads. Before the energy storage battery begins formal charging, a pre-charge closing strategy is required to achieve smooth connection to the DC bus, avoiding a huge inrush current (possibly more than 10 times the normal charging current) at the moment of closing due to excessive voltage difference between the photovoltaic energy storage battery and the DC bus (such as a bus voltage of 300V and a photovoltaic energy storage battery terminal voltage of 100V), thereby protecting the battery's internal electrodes, DC bus switches, controllers, and other equipment from damage.

[0040] The pre-charge closing strategy is a set of gradual connection control logic for the initial connection of photovoltaic energy storage batteries and DC bus. It typically includes the following steps: Voltage detection: Before closing, the DC bus voltage and battery terminal voltage are detected, and the difference between the two is calculated (e.g., the maximum allowable voltage difference ΔU ≤ 50V). If the voltage difference exceeds the limit, closing is temporarily suspended to avoid direct impact; Current-limited pre-charge: Through a pre-charge resistor or controllable switch (instead of directly closing the main contactor), the DC bus energy is allowed to slowly charge the battery with a low current (e.g., 0.1C, where C is the battery's rated capacity), gradually reducing the voltage difference between the two (e.g., from 100V to 280V, close to the bus's 300V); Closing judgment: When the battery terminal voltage U at With DC bus voltage U us The difference ΔU (ΔU=|U at -U us If the voltage decreases to a safe range (i.e., ΔU≤20V) and the pre-charge current decreases steadily (indicating that the voltage is approaching equilibrium), then the pre-charge circuit is disconnected, the main contactor is closed, the circuit is closed, and the battery is officially connected to the DC bus to enter the subsequent charging stage (such as constant current charging).

[0041] The execution process of the pre-charge closing strategy is monitored by collecting the bus voltage value in real time through a voltage sensor configured on the DC bus (sampling frequency not less than 1kHz), and recording the voltage data sequence at preset time intervals (e.g., 10 milliseconds / time). The continuously collected voltage data is processed using a sliding window algorithm to calculate the voltage change per unit time (i.e., the ratio of the voltage difference between two adjacent sampling times to the time interval), and the instantaneous voltage rise rate is obtained. By taking the average of multiple samples (e.g., the arithmetic mean of 10 consecutive instantaneous rates), high-frequency noise interference is eliminated, and a stable DC bus voltage rise rate is finally obtained. This rate is then compared with a preset voltage rise rate reference range in the database. If the DC bus voltage rise rate does not belong to the voltage rise rate reference range, the charging and discharging current of the photovoltaic energy storage battery is limited. At the same time, the operating data of the photovoltaic energy storage battery is transmitted to the cloud platform or monitoring center after data standardization.

[0042] The core logic of limiting the charging and discharging current of photovoltaic energy storage batteries is to forcibly constrain the current within a safe threshold through the coordinated control of the battery management system and the inverter, thereby breaking the vicious cycle of abnormal voltage rise rate and current surge. A voltage rise rate deviating from the reference range indicates a risk of voltage imbalance during the pre-charge closing phase. Maintaining the original current at this time may lead to problems such as DC bus overvoltage and increased battery electrode polarization, further amplifying system anomalies. Current limiting can quickly reduce energy transmission intensity, curb abnormal voltage trends, and prevent equipment damage due to overcurrent and overvoltage. It also buys time for the cloud platform to diagnose the cause of the anomaly, ensuring safety and controllability during the pre-charge phase. Specifically, when a DC bus voltage is detected... When the rate of increase deviates from the reference range, the battery management system immediately issues a current limiting command to the inverter, setting the maximum allowable value of the charging and discharging current to a very low percentage of the battery's rated capacity (e.g., ≤0.05C, where C is the battery's rated capacity). At the same time, it locks the current regulation authority, prohibiting the inverter from performing any operation that might cause the current to exceed the maximum allowable value. This process is achieved through hardware-level current limiting of the drive circuit (e.g., pulse width limiting to trigger the IGBT switch) and software-level control algorithm intervention (e.g., cutting off the command output in the current closed-loop control), ensuring that the current drops below the limit value within milliseconds, and preventing the current surge caused by the abnormal voltage rise rate from further exacerbating the system risk.

[0043] If the voltage rise rate of the DC bus falls within the voltage rise rate reference range, then the actual internal resistance of the photovoltaic energy storage battery and its operational anomaly index are obtained. Using the internal resistance detection module on the battery management system, the change in battery terminal voltage (ΔU) before and after discharge is simultaneously collected via DC discharge (applying a short, low-amplitude constant discharge current, such as 0.1C, to the battery). B ) and discharge current value (I); based on Ohm's law, the derived formula (actual internal resistance R=ΔU) B / I) The actual internal resistance is calculated and compared with the reference internal resistance range determined based on the photovoltaic energy storage battery's operational anomaly index. Using the operational anomaly index as the core basis, technicians combine the standard internal resistance characteristics of photovoltaic energy storage battery types (such as lithium iron phosphate and ternary lithium) to dynamically correlate the degree of anomaly with the internal resistance adaptation range. The higher the anomaly index, the more severe the battery aging or damage. The upper limit of the reference internal resistance range is adjusted upwards and the lower limit is adjusted downwards to form an internal resistance benchmark range that matches the current health status. Because the actual internal resistance needs to be combined with the degree of battery operational anomaly to determine whether it is normal, if a fixed standard is used without considering the operational anomaly index, the reasonable internal resistance of an aging photovoltaic energy storage battery may be mistakenly judged as abnormal, or potential internal resistance anomalies (such as short circuit precursors) of healthy batteries may be ignored. By dynamically determining the reference range, the internal resistance comparison can be made more consistent with the actual state of the battery, providing an accurate basis for subsequent identification of short circuit risks, abnormal aging, and other issues.

[0044] If the actual internal resistance of the photovoltaic energy storage battery is less than the lower limit of the reference internal resistance range, it is a dangerous abnormality such as a short circuit precursor. The battery management system will trigger the hardware protection mechanism to prohibit current flow. For example, the main contactor and pre-charge contactor in the photovoltaic energy storage battery circuit will be immediately disconnected to cut off the charging and discharging path. At the same time, the inverter will be linked to stop energy interaction and completely block the current flow. This will prevent any current from passing through the photovoltaic energy storage battery. The operating data of the photovoltaic energy storage battery will be transmitted to the cloud platform or monitoring center after data standardization.

[0045] The Battery Management System (BMS) is the core control and monitoring unit of photovoltaic energy storage batteries. Its main functions include: real-time acquisition of battery state parameters such as voltage, current, and temperature; estimation of state of charge and health status; implementation of charge and discharge protection (such as overvoltage, overcurrent, and overtemperature protection); equalization of individual cell states; and communication with inverters and other equipment to coordinate and regulate battery operation, ensuring its safe, efficient, and long-life operation.

[0046] If the actual internal resistance of the photovoltaic energy storage battery is within the reference internal resistance range, it indicates that the battery aging degree is in line with the expected current operating state and is within the normal aging range. At this time, it is determined that no intelligent control management will be implemented for the charging process of the photovoltaic energy storage battery. No additional intelligent control is required for the charging process. The battery management system will manage the charging and discharging according to the conventional logic to ensure that the charging process conforms to the suitable operating conditions after the battery has aged normally, taking into account both safety and operating efficiency.

[0047] If the actual internal resistance of the photovoltaic energy storage battery is greater than the upper limit of the reference internal resistance range, the photovoltaic energy storage battery is in an abnormal aging state. Therefore, it is necessary to implement intelligent control management for the charging process of the photovoltaic energy storage battery and apply additional intelligent control to the charging process.

[0048] At the same time, the duration of photovoltaic energy storage batteries in an abnormal aging state is updated. If the duration is greater than or equal to the defined duration, an early warning is issued.

[0049] The defined duration refers to the maximum safe duration for which the photovoltaic energy storage battery is allowed to be in an abnormal state. When setting this duration, relevant technical personnel need to combine the aging tolerance characteristics of the battery type (such as lithium iron phosphate and ternary lithium), the reliability requirements of the actual application scenario (such as residential and industrial / commercial energy storage), and historical fault data, and determine it through simulation testing and on-site verification (such as setting it to 72 hours) to avoid safety risks or sudden performance degradation caused by abnormal aging for a long period of time. When an early warning is issued, the battery management system will standardize the warning information (including abnormal aging duration, current internal resistance, and temperature data) and upload it to the cloud platform or monitoring center through the communication module, and push it to the operation and maintenance personnel's terminal (such as mobile APP and computer client) to prompt timely intervention for investigation and maintenance.

[0050] Specifically, the charging process of photovoltaic (PV) energy storage batteries is intelligently controlled and managed. The management process involves tightening the temperature control threshold range of the PV energy storage battery based on its operational anomaly index. This temperature control threshold range is the normal temperature range. Depending on the severity of the operational anomaly index, the temperature control threshold range is narrowed according to different preset gradients in the database. For example, if the original range is 10~40℃, and the temperature is normal within this range, a slight anomaly index tightens it to 15~35℃; a moderate anomaly further tightens it to 20~30℃, with the tightening increasing as the operational anomaly index rises. If the PV energy storage battery is in an abnormal aging state, it means it may be in a potentially risky operating condition (such as poor heat dissipation or abnormal partial discharge), at which point the original temperature control threshold can no longer meet safety requirements. By tightening the range, temperature control measures (such as starting the cooling fan or pausing charging and discharging) can be triggered earlier, preventing overheating faults caused by the PV energy storage battery continuously deviating from the safe range.

[0051] During charging, if abnormal temperature conditions occur in the photovoltaic (PV) energy storage battery, the power of the PV energy storage battery is reduced based on its operational anomaly index. If the abnormal temperature conditions persist after the reduction, the PV energy storage battery terminates its current charging and discharging operation. When abnormal temperature conditions occur during charging, the power reduction based on the operational anomaly index must be implemented in a step-by-step manner according to the severity of the operational anomaly index. For example, if the operational anomaly index is low, the power is reduced to 80% of the rated power; if the operational anomaly index is high, it is reduced to 50%. The larger the operational anomaly index, the greater the power reduction, to avoid a single large power reduction impacting the system. The reason for reducing power based on the operational anomaly index is that abnormal temperature is often related to an imbalance in the current operating state of the battery, and the operational anomaly index reflects the severity of the imbalance. Dynamically reducing power through the operational anomaly index of the PV energy storage battery can accurately reduce the energy conversion intensity of the battery, reduce heat generation, and alleviate the abnormal temperature trend from the source. If the power is not reduced or is reduced blindly, the temperature may continue to rise, causing safety risks, or the power reduction may be insufficient to contain the anomaly. Therefore, this operation is a key step in balancing system stability and battery safety.

[0052] Abnormal temperature conditions refer to a situation where the temperature of a photovoltaic energy storage battery is not within the temperature control threshold range for a duration greater than or equal to the defined duration.

[0053] After the pre-charge closing strategy is executed, the photovoltaic (PV) energy storage battery enters the constant current charging stage. The base current change rate of the PV energy storage battery is obtained, and the current change rate reduction is determined based on the PV energy storage battery's operational anomaly index. The base current change rate of the PV energy storage battery is preset by the battery management system based on the battery's rated capacity, current state of charge, and normal charging requirements, guiding the smooth rise and fall of the current to adapt to the normal charging process. The determination of the current change rate reduction needs to be combined with the specific value of the operational anomaly index: by dividing the operational anomaly index into different intervals, corresponding to different current change rate reductions (e.g., the current change rate reduction corresponding to a certain operational anomaly index interval is 10% of the base current change rate), ensuring that the reduction accurately matches the current abnormal state of the battery. Subtracting the current change rate reduction from the base current change rate of the PV energy storage battery yields the current change rate of the PV energy storage battery. The reason for subtracting this amount from the base current change rate is that when the photovoltaic energy storage battery is in an abnormal aging state, maintaining the base current change rate can easily lead to excessively rapid current changes, further amplifying the abnormal problem. By dynamically adjusting the rate, the current rise and fall can be slowed down, reducing the battery's operating pressure, avoiding the expansion of risks, and ensuring the safety and stability of the charging process.

[0054] The core of correcting the target current value during constant current charging based on the abnormal operation index of photovoltaic energy storage batteries is to adapt to the reduced load-bearing capacity of photovoltaic energy storage batteries after aging. Abnormal aging will lead to the deterioration of the electrode structure and the increase of internal resistance of photovoltaic energy storage batteries. If the normal target current is maintained, it is easy to cause problems such as intensified polarization and excessive temperature rise during charging, which will further accelerate the shedding of electrode active materials and electrolyte decomposition, forming a vicious cycle of current overload and aggravated abnormal aging. By increasing the current reduction by increasing the abnormal operation index, the energy input intensity of photovoltaic energy storage batteries during charging can be reduced, the internal chemical reaction pressure can be reduced, and safety risks (such as overheating and bulging) caused by the current exceeding the tolerance limit of abnormally aged batteries can be avoided. At the same time, the aging process can be slowed down, ensuring that photovoltaic energy storage batteries can still function stably within their remaining lifespan.

[0055] When photovoltaic energy storage batteries are in an abnormal aging state, the target current value of the constant current charging stage is reduced based on the operation anomaly index. First, the conventional target current preset by the battery management system should be used as a benchmark, and then the correction range should be determined according to the operation anomaly index. For example, if the operation anomaly index is in the mild anomaly range, the target current is reduced by 10%-15% of the benchmark current; if the operation anomaly index enters the moderate anomaly range, the reduction ratio is increased to 20%-30%; if the operation anomaly index belongs to the severe anomaly range, the reduction ratio is further increased to 35%-50%, and the higher the operation anomaly index, the greater the reduction ratio.

[0056] The constant current charging process of the photovoltaic energy storage battery is monitored. If abnormal charging conditions occur, the rate of change of current in the photovoltaic energy storage battery is further reduced. Abnormal charging conditions refer to situations where the voltage of a single battery cell exceeds its upper limit (U0). i >U imax The battery pack temperature rise rate exceeds the limit (dT / dt > [dT / dt]). max ), Charging current fluctuation exceeds the standard (ΔI>ΔI) max Or the difference between the battery terminal voltage and the DC bus voltage is abnormal (ΔU>ΔU). max ), where U i dT / dt is the single cell voltage, ΔI is the temperature rise rate, ΔU is the current fluctuation value, and ΔU is the difference between the terminal voltage and the bus voltage. The subscript max represents the upper limit value of the corresponding parameter.

[0057] If the above-mentioned abnormal conditions occur, when reducing the current change rate again, the current change rate should be used as the benchmark, and the secondary reduction should be determined based on the severity of the abnormal conditions: for example, if the single cell voltage exceeds the upper limit by less than 10%, the rate should be reduced by 15%-20% of the current rate; if the voltage exceeds the upper limit by more than 10% or multiple abnormalities are triggered simultaneously, the reduction ratio should be increased to 25%-35%, and the more severe the abnormality, the greater the secondary reduction should be; at the same time, the battery management system should be used to verify the compatibility between the adjusted rate and the battery in real time to avoid the charging process from being stopped due to the rate being too low, and finally to achieve closed-loop control from abnormal triggering to rate reduction to risk mitigation. The specific control strategy shall be specified by relevant technical personnel.

[0058] Based on the rate of change of the photovoltaic energy storage battery's current, the charging current of the photovoltaic energy storage battery is gradually increased to the corrected target current value. The photovoltaic energy storage battery is then continuously charged according to the corrected target current value until the voltage of the photovoltaic energy storage battery increases to the corrected target voltage value.

[0059] Due to factors such as the accuracy of current detection, controller response delay, fluctuations in the output characteristics of power devices, and input disturbances from the power grid or photovoltaic side in the actual system, there will be a slight allowable deviation between the final stable charging current and the corrected target current value.

[0060] When the constant current charging termination condition is met, it indicates that the constant current charging stage has ended and the photovoltaic energy storage battery has entered the constant voltage charging stage, thereby monitoring the constant voltage charging process of the photovoltaic energy storage battery; in an example embodiment, the constant current charging termination condition refers to the photovoltaic energy storage battery voltage increasing to the corrected target voltage value.

[0061] The corrected target voltage value specifically refers to the following: When the charging current of the photovoltaic (PV) energy storage battery increases to the corrected target current value, the first deviation factor of the PV energy storage battery is obtained and compared with the defined deviation factor. If the first deviation factor of the PV energy storage battery is less than the defined deviation factor, the target voltage value is corrected based on the PV energy storage battery's operational anomaly index. This is calculated by subtracting the operational anomaly index from 1 and multiplying the result by the target voltage value determined by the battery management system. The result is the corrected target voltage value. If the first deviation factor of the PV energy storage battery is greater than or equal to the defined deviation factor, the target voltage value is corrected based on both the first deviation factor and the operational anomaly index. This is calculated by subtracting the first deviation factor from 1, multiplying the result by subtracting the operational anomaly index from 1, and then multiplying the result by the target voltage value determined by the battery management system. The result is the corrected target voltage value; the first deviation factor refers to the deviation between the current key operating parameters of the photovoltaic energy storage battery (such as cell voltage, real-time temperature, internal resistance, etc.) and the corresponding standard values ​​(such as rated voltage, safe temperature range, and reference internal resistance at this current) when the charging current of the photovoltaic energy storage battery is increased to the corrected target current value. After normalization (eliminating the differences in units of different parameters and mapping the deviation values ​​uniformly to the 0-1 range), the deviation factor is calculated by weighting each parameter according to its influence on charging safety (such as voltage deviation weight set to 0.4, temperature deviation weight set to 0.3, and internal resistance deviation weight set to 0.3). The final quantitative index has a value range between 0 and 1 and is used to intuitively reflect the degree of deviation between the actual operating state of the battery and the ideal state at the current current. It provides data support for whether to correct the target voltage value in the future. The deviation factor is defined as the upper limit value of the first deviation factor stored in the database.

[0062] When the first deviation factor is less than the defined deviation factor, the actual operating state of the battery deviates little from the ideal state. Only the target voltage needs to be corrected in conjunction with the operating anomaly index. Since the operating anomaly index can reflect the degree of non-aging-related anomalies in the battery, the voltage can be slightly adjusted to adapt to the current abnormal state. This avoids over-correction that could affect charging efficiency and also mitigates the risk of anomaly expansion in advance. When the first deviation factor is greater than or equal to the defined deviation factor, the battery state deviates significantly from the ideal value. It is necessary to combine the deviation factor and the anomaly index for double correction, which can significantly reduce the target voltage and avoid problems such as increased polarization and overheating caused by excessively high voltage under high deviation conditions, thus achieving more cautious voltage control.

[0063] Furthermore, the constant voltage charging process of the photovoltaic energy storage battery is monitored. The specific monitoring process is as follows: the duration of the constant voltage monitoring cycle is determined based on the operation anomaly index of the photovoltaic energy storage battery. That is, the correspondence between the operation anomaly index and the duration of the constant voltage monitoring cycle stored in the database is queried to obtain the duration of the corresponding constant voltage monitoring cycle.

[0064] During the constant voltage monitoring cycle, the second deviation factor of the photovoltaic energy storage battery is obtained in the same way as the first deviation factor, with the only difference being the time. It is then compared with the defining deviation factor. If the second deviation factor of the photovoltaic energy storage battery is greater than or equal to the defining deviation factor, the tail current magnitude is corrected based on the second deviation factor and the photovoltaic energy storage battery's operational anomaly index. The reciprocal of the second deviation factor of the photovoltaic energy storage battery is multiplied by the reciprocal of the photovoltaic energy storage battery's operational anomaly index, and then multiplied by the tail current magnitude to obtain the corrected tail current magnitude. At the same time, the tail current judgment time is reduced. That is, 1 minus the result of the second deviation factor of the photovoltaic energy storage battery, multiplied by 1 minus the result of the photovoltaic energy storage battery's operational anomaly index, and then multiplied by the tail current judgment time. The result is the reduced tail current judgment time. It should be noted that under the condition that the second deviation factor of the photovoltaic energy storage battery is greater than or equal to the defining deviation factor, the deviation factor is not 0.

[0065] If the second deviation factor of the photovoltaic energy storage battery is less than the defined deviation factor, the tail current magnitude is corrected based on the photovoltaic energy storage battery's operational anomaly index. That is, the reciprocal of the photovoltaic energy storage battery's operational anomaly index is multiplied by the tail current magnitude to obtain the corrected tail current magnitude. At the same time, the tail current determination time is reduced. The result of subtracting the photovoltaic energy storage battery's operational anomaly index from 1 and multiplying it by the tail current determination time is the reduced tail current determination time.

[0066] When the second deviation factor is greater than or equal to the defined deviation factor, the battery's operating state deviates significantly from the ideal range. Aging further reduces the battery's current tolerance and thermal management capabilities. In this case, by using both the second deviation factor and the operating anomaly index to correct the tail current, the current intensity can be precisely reduced to curb the expansion of the deviation, while also adapting to the reduced load-bearing limit of the aging battery, avoiding the aggravation of electrode aging damage due to current overload. At the same time, reducing the judgment time can shorten the duration of the abnormal state, preventing overcurrent and overtemperature faults caused by abnormally aged batteries being under high load for a long time. When the second deviation factor is less than the defined deviation factor, although the battery state deviation is small, abnormal aging weakens the battery's ability to resist potential risks. Correcting the tail current based solely on the operating anomaly index can adapt to the vulnerability of the aging battery in advance and avoid potential risks. Reducing the judgment time can speed up the tail current judgment rhythm, avoiding excessively long residual current in the later stages of charging due to judgment lag. This prevents polarization accumulation in abnormally aged batteries due to prolonged low-current charging, ensuring charging safety in the constant voltage stage, and also avoids excessively long charging time and improves charging efficiency, ultimately achieving dynamic safety control of the constant voltage stage operation of aging photovoltaic energy storage batteries.

[0067] When the constant voltage charging termination condition is met, it indicates the end of the constant current charging phase and the start of the float charging phase for the photovoltaic energy storage battery. The photovoltaic energy storage battery is continuously float charged based on the corrected tail current. The constant voltage charging termination condition mainly consists of two quantitative standards, as follows: First, the charging current decays to the corrected tail current; second, the constant voltage charging duration reaches the preset upper limit. When either condition is met, the constant voltage charging is determined to be over, and the photovoltaic energy storage battery enters the float charging phase.

[0068] At the same time, the parameters of the photovoltaic energy storage battery are reinitialized.

[0069] Figure 4 This is a circuit diagram of the battery float charging interface provided in this embodiment of the invention. From right to left, the circuit sequentially completes battery connection, safety and EMI suppression, bus energy storage and current detection, and low-side PWM drive of the contactor coil: the positive terminal of the battery is connected to BAT+ via fuses BAT1+_IN and BAT2+_IN through fuses FU1 / FU2, and the negative terminal is connected to BAT−; to discharge common-mode interference and meet disturbance and safety requirements, BAT+ and BAT− are connected to PE via Y capacitors respectively. An X capacitor and a common-mode choke are arranged between BAT+ and BAT− to form a π-type filter, suppressing high-frequency switching noise from the charger / inverter from flowing back to the battery side. Simultaneously, multiple 100kΩ discharge resistor chains (such as R506) are used for... The filter capacitor provides a discharge path and facilitates bus voltage detection; the large-capacity DC-link (busbar) capacitor between BAT+ and BAT− is used to stabilize the DC bus voltage; the main circuit is connected in series with a Hall current sensor to send the battery current to the control board for tail current judgment, current limiting closed loop and protection action in the constant voltage stage; the leftmost part is the low-side switch drive of the two main contactor coils, LBAT1 / LBAT2 are the coil return terminals; the whole serves as the battery-bus float charging interface, providing safe connection / disconnection, noise and inrush current suppression, bus voltage stabilization and accurate current measurement during the charging control process, making the judgment and protection in the constant voltage-tail current stage more robust, thereby achieving controllable, low ripple and lifespan friendly float charging.

[0070] Furthermore, the parameters of the photovoltaic energy storage battery are re-initialized. The specific initialization process is as follows: based on the first deviation factor and the second deviation factor of the photovoltaic energy storage battery, the total deviation factor of the photovoltaic energy storage battery is obtained and compared with the defined total deviation factor. The defined total deviation factor is the upper limit of the total deviation factor allowed by the database.

[0071] If the total deviation factor of the photovoltaic energy storage battery is greater than the defined total deviation factor, then based on the total deviation factor of the photovoltaic energy storage battery, the additional increment of the operation anomaly index is increased. The total deviation factor of the photovoltaic energy storage battery is divided by the defined total deviation factor, and the result is multiplied by the current additional increment of the operation anomaly index. The result is the additional increment of the operation anomaly index after re-initialization. Thus, the additional increment of the operation anomaly index of the photovoltaic energy storage battery is re-initialized. At the same time, the number of charging times is updated, thus re-initializing the theoretical increment of the operation anomaly index of the photovoltaic energy storage battery.

[0072] If the total deviation factor of the photovoltaic energy storage battery is greater than the defined total deviation factor, the number of charging cycles is updated, thereby re-initializing the theoretical increment of the photovoltaic energy storage battery's operational anomaly index.

[0073] After the entire charging process is completed, the cumulative number of charging cycles is updated synchronously. Based on the preset "charging cycles - theoretical increment of operational anomaly index" correlation rules in the database (e.g., after every 10 or 20 complete charging cycles, the theoretical increment of the operational anomaly index increases by 0.01-0.03 compared to the current theoretical increment of the operational anomaly index; the specific number of cycles and increment values ​​need to be determined in conjunction with battery type, design life, and historical degradation data), the theoretical increment of the operational anomaly index is re-initialized. The core of this approach is to match the increment of the anomaly index with the battery cycle wear progress: as the number of charging cycles accumulates, the battery aging gradually deepens. A small increase in the theoretical increment after each fixed number of charging cycles allows the operational anomaly index to more accurately reflect the potential anomaly risks brought about by battery cycle use, providing a benchmark that is close to the actual wear and tear for parameter corrections (such as current and voltage adjustments) in subsequent charging stages.

[0074] Optionally, the operation anomaly index of the photovoltaic energy storage battery is analyzed as follows: the degree of deviation of the operation state of the photovoltaic energy storage battery is analyzed, that is, the theoretical increment of the operation anomaly index of the photovoltaic energy storage battery and the operation anomaly factor of the photovoltaic energy storage battery are obtained and coupled to obtain the operation anomaly index of the photovoltaic energy storage battery, with a value range of (0, 1).

[0075] To obtain the theoretical increment of the photovoltaic energy storage battery operation anomaly index, technicians must first set an initial value based on battery characteristics. This initial theoretical increment (e.g., 0.005 for a brand-new battery) is determined according to parameters such as battery type (e.g., lithium iron phosphate, ternary lithium), rated capacity, and design cycle life, serving as a benchmark for dynamic index adjustment. During subsequent battery operation, this theoretical increment gradually increases with the cumulative number of charging cycles. The more charging cycles, the more significant the battery aging and cycle loss. The upward adjustment of the theoretical increment can be dynamically calibrated based on actual degradation data, ensuring that the increment always matches the potential anomaly risks brought about by battery cycle use, providing a dynamic benchmark for accurate calculation of the operation anomaly index.

[0076] The operational anomaly index of photovoltaic (PV) energy storage batteries is a comprehensive indicator used to quantify the aging state of PV energy storage batteries. It is the superposition of the theoretical aging degree of the PV energy storage battery based on material characteristics and theoretical cycle degradation laws, and the aging degree of the PV energy storage battery caused by actual operation. The specific expression is as follows:

[0077] ;

[0078] In the formula, A_OSDD is the operational anomaly index of the photovoltaic energy storage battery, B_OSDD is the operational anomaly factor of the photovoltaic energy storage battery, and L_OSDD is the theoretical increment of the operational anomaly index of the photovoltaic energy storage battery.

[0079] The specific analysis process for abnormal operating factors of photovoltaic energy storage batteries is as follows: The historical maximum capacity decay rate, historical maximum capacity deviation rate, and historical maximum temperature rise rate of the photovoltaic energy storage battery are extracted from its operating data. The historical maximum capacity decay rate refers to the maximum capacity decrease per unit time (e.g., per month or per hundred charging cycles) since the battery began operation, reflecting the fastest aging trend the battery has ever experienced. The historical maximum capacity deviation rate refers to the maximum percentage deviation (including positive and negative deviations) between the battery's actual capacity and rated capacity, reflecting the extreme degree of battery capacity fluctuation. The historical maximum temperature rise rate refers to the maximum temperature increase per unit time (e.g., per minute or per hour) during battery operation, reflecting the most severe thermal runaway risk the battery has ever faced. All of these are extracted from the historical data logs of the battery management system.

[0080] It's important to explain that during a single charge of a photovoltaic energy storage battery, its operational anomaly index remains fixed and is not adjusted based on real-time fluctuations in the charging process. Only after the entire charging cycle (including constant current, constant voltage, and float charging stages) is completed is the operational anomaly index updated and calibrated, incorporating the charging data and the cumulative number of charges. This prevents frequent index changes due to short-term fluctuations in battery status during a single charge, thus avoiding frequent adjustments to control parameters and ensuring the stability of the control logic for that charging phase. Simultaneously, the updated index accurately integrates the losses and anomaly information from this charge, providing an accurate benchmark for parameter correction in the next charge, achieving consistency and stability in charging management.

[0081] By normalizing the historical maximum capacity decay rate, historical maximum capacity deviation rate, and historical maximum average temperature rise rate, the incomparability of these parameters due to differences in dimensions and numerical ranges is eliminated, giving the normalized parameters an equal weighting basis for calculation. Based on this, an additional aging degree quantification value caused by non-standard operating conditions during actual operation of the photovoltaic energy storage battery is further superimposed. A preset weighted algorithm is used to integrate and calculate the normalized parameters and the additional aging degree quantification value, ultimately yielding an operational anomaly factor for the photovoltaic energy storage battery that comprehensively reflects the aging degree of the photovoltaic energy storage battery during actual operation. The specific expression is as follows:

[0082] ;

[0083] In the formula, B_OSDD is the operational anomaly factor of the photovoltaic energy storage battery, EX_OSDD is the additional increment of the operational anomaly index of the photovoltaic energy storage battery, Z1 is the preset capacity decay rate metric in the database, representing the proportion of capacity decay rate to the operational anomaly index, Z2 is the preset capacity deviation rate metric in the database, representing the proportion of capacity deviation rate to the operational anomaly index, Z3 is the preset temperature rise rate metric in the database, representing the proportion of temperature rise rate to the operational anomaly index, and HM CAR This represents the historical maximum capacity degradation rate of photovoltaic energy storage batteries, according to JHM. CAR CHM is the defined capacity degradation rate for photovoltaic energy storage batteries, representing the maximum allowable capacity degradation rate. CAR The reference capacity degradation rate for photovoltaic (PV) energy storage batteries refers to the baseline capacity degradation rate, preset in the technical specifications, reflecting the performance degradation law of PV energy storage batteries under standard design conditions (such as rated temperature and rated charge / discharge current). HM CDR The highest historical capacity deviation rate for photovoltaic energy storage batteries, JHM CDR CHM is the defined capacity deviation rate for photovoltaic energy storage batteries, representing the upper limit of the capacity deviation rate. CDR The reference capacity deviation rate (HM) for photovoltaic (PV) energy storage batteries refers to the baseline capacity deviation rate, preset in the technical specifications, reflecting the performance degradation pattern of PV energy storage batteries under standard design conditions (such as rated temperature and rated charge / discharge current). ATR This represents the highest temperature rise rate in the history of photovoltaic energy storage batteries, according to JHM. ATR CHM is the defined temperature rise rate for photovoltaic energy storage batteries, representing the upper limit of the temperature rise rate. ATR The reference temperature rise rate for photovoltaic energy storage batteries refers to the baseline temperature rise rate preset in the technical specifications under standard design conditions (such as rated temperature and rated charge / discharge current) that reflects the performance degradation law of photovoltaic energy storage batteries.

[0084] The additional increment of the operational anomaly index for photovoltaic (PV) energy storage batteries refers to the quantified value of the additional aging degree caused by non-standard operating conditions during actual operation. This value needs to be initially set by technical personnel based on battery design characteristics, application scenarios, and safety redundancy requirements. For example, for lithium iron phosphate (LFP) PV energy storage batteries, the basic additional increment can be set to 0.02. This value needs to be determined with reference to the battery's rated aging rate, historical anomaly data, and industry risk management standards, serving as the initial incremental benchmark for responding to potential sudden anomalies. During actual battery operation, this additional increment will dynamically change according to the operating conditions.

[0085] The values ​​of the metrics all range from 0 to 1. By running the anomaly factor formula, all parameters can be uniformly mapped to the same dimension. Subtracting the corresponding reference value anchors the parameter benchmark. The reference value represents the standard value of the parameter during normal battery operation (such as the rated capacity decay rate and the allowable temperature rise rate). Subtracting this value accurately extracts the deviation of the parameter from the normal state, avoiding interference from normal values ​​in the judgment of the degree of anomaly. Dividing by the corresponding threshold value minus the corresponding reference value standardizes the deviation. The threshold value is the upper limit of the parameter safety threshold. This difference represents the total deviation range between normal and critical. After dividing the range, the deviation of each parameter can be converted into a relative value in the 0-1 range. This ensures that the normalized parameters have an equal weight in the calculation, preventing any single parameter from excessively dominating the result due to its large absolute value. On this basis, the additional aging quantification value under non-standard operating conditions and the operation anomaly index obtained by weighted algorithm integration are superimposed. The value is limited to the 0-1 range because the normalized parameters are already in the 0-1 range, and the additional aging quantification value is also set in the 0-1 range according to the same logic (0 represents no additional aging, 1 represents additional aging reaching the critical state). The result after weighted calculation is naturally constrained to 0-1. This range can intuitively reflect the degree of aging, with 0 representing no abnormal aging of the battery, 1 representing aging reaching the critical state, and the intermediate value corresponding to the severity of aging proportionally.

[0086] Since both the additional increment of the photovoltaic energy storage battery's operational anomaly index and the theoretical increment of the photovoltaic energy storage battery's operational anomaly index are relatively small, the value range of the photovoltaic energy storage battery's operational anomaly index is also within the range of 0-1.

[0087] An excessively high historical maximum temperature rise rate accelerates the shedding of active materials from battery electrodes and the decomposition of electrolyte, leading to an increased historical maximum capacity decay rate. Conversely, an increased historical maximum capacity decay rate means a higher probability of deviation between the battery's actual capacity and rated capacity, further widening the historical maximum capacity deviation rate. This creates a chain reaction, from excessively high temperature rise rate to accelerated capacity decay to increased capacity deviation. These three parameters collectively affect the operational anomaly factor. A higher historical maximum capacity decay rate indicates more severe long-term aging and wear of the battery, directly increasing the baseline value of the operational anomaly factor under otherwise unchanged conditions. A higher historical maximum capacity deviation rate reflects poorer battery capacity stability, further increasing the operational anomaly factor by increasing the risk of capacity fluctuations under otherwise unchanged conditions. A higher historical maximum temperature rise rate indicates a more severe risk of thermal runaway faced by the battery, amplifying the operational anomaly factor by amplifying thermal safety hazards under otherwise unchanged conditions. Ultimately, the operational anomaly factor comprehensively reflects the battery's historical extreme risks in terms of capacity decay, capacity stability, and thermal safety, providing a comprehensive early warning basis for subsequent charging management.

[0088] Figure 3 This is a schematic diagram of the structure of an intelligent management and protection device for a photovoltaic energy storage battery provided by an embodiment of the present invention. Optionally, the intelligent management and protection device for a photovoltaic energy storage battery may include a first processor 2001. Optionally, the intelligent management and protection device for a photovoltaic energy storage battery may further include a memory 2002 and a transceiver 2003, wherein the first processor 2001, the memory 2002, and the transceiver 2003 can be connected via a communication bus. The first processor 2001 is the control center of the intelligent management and protection device for a photovoltaic energy storage battery, and may be a single processor or a collective term for multiple processing elements. Optionally, the first processor 2001 can execute various functions of the intelligent management and protection device for a photovoltaic energy storage battery by running or executing software programs stored in the memory 2002 and calling data stored in the memory 2002. In a specific implementation, as one embodiment, the first processor 2001 may include one or more CPUs, for example... Figure 3 CPU0 and CPU1 are shown in the diagram.

[0089] The memory 2002 stores the software program for executing the present invention and is controlled by the first processor 2001 for execution. Specific implementation details can be found in the above method embodiments and will not be repeated here. The memory 2002 can be integrated with the first processor 2001 or exist independently. The transceiver 2003 is used for communication with network devices or with terminal devices. Optionally, the transceiver 2003 may include a receiver and a transmitter. Figure 3(Not shown separately). The receiver is used to implement the receiving function, and the transmitter is used to implement the transmitting function. Optionally, the transceiver 2003 can be integrated with the first processor 2001, or it can exist independently, and is connected to the interface circuit of a photovoltaic energy storage battery intelligent management and protection device (…). Figure 3 (Not shown in the image) is coupled to the first processor 2001.

[0090] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A smart management and protection system for photovoltaic energy storage cells, characterized in that, The system comprises: a remote maintenance module for collecting operation data of the photovoltaic energy storage battery through a communication module built in the inverter and performing remote data transmission, so as to monitor the operation state of the photovoltaic energy storage battery in real time; a charging control module for judging whether the photovoltaic energy storage battery is in a charging state based on the operation data of the photovoltaic energy storage battery, if yes, analyzing the deviation degree of the operation state of the photovoltaic energy storage battery, so as to determine whether to intelligently control and manage the charging process of the photovoltaic energy storage battery, if no, continuously collecting the operation data of the photovoltaic energy storage battery; an island protection module for realizing island protection when an island signal is detected, and meanwhile the photovoltaic energy storage battery cooperates with the inverter to enter an off-grid mode to continuously supply power to local loads.

2. The intelligent management and protection system for photovoltaic energy storage cells according to claim 1, characterized in that, The communication module built in the inverter comprises a WIFI stick, a WIFI communication circuit, a CAN communication circuit and a communication protocol, wherein the WIFI stick and the WIFI communication circuit are responsible for wireless data transmission, the CAN communication circuit is responsible for battery state monitoring and control, and the communication protocol defines the format and rules of data transmission; The remote data transmission specifically refers to transmitting the operation data of the photovoltaic energy storage battery to a cloud platform or a monitoring center after data standardization, and the remote data transmission mode is WIFI communication; In the process of monitoring the operation state of the photovoltaic energy storage battery in real time, the photovoltaic energy storage battery can also be remotely controlled and fault diagnosed and warned.

3. The intelligent management and protection system for photovoltaic energy storage cells as claimed in claim 1 wherein, The specific process of realizing island protection is as follows: whether island effect occurs is detected through a detection algorithm; if island effect occurs, i.e. an island signal is detected, a high-speed controller cooperates with the photovoltaic energy storage battery to control the connection between the photovoltaic energy storage battery and the power grid to be cut off and an alarm signal is sent, so as to realize island protection, and meanwhile the photovoltaic energy storage battery cooperates with the inverter to enter an off-grid mode to continuously supply power to local loads; if island effect does not occur, i.e. an island signal is not detected, whether island effect occurs is continuously detected through the detection algorithm.

4. The intelligent management and protection system for photovoltaic energy storage cells as claimed in claim 1 wherein, The specific determination process of determining whether to intelligently control and manage the charging process of the photovoltaic energy storage battery is as follows: the controller on the photovoltaic side sends energy to a DC bus and executes a pre-charging closing strategy; the execution process of the pre-charging closing strategy is monitored to obtain the voltage rise rate of the DC bus, which is compared with a voltage rise rate reference interval, if the voltage rise rate of the DC bus does not belong to the voltage rise rate reference interval, the charging and discharging current of the photovoltaic energy storage battery is limited, and the operation data of the photovoltaic energy storage battery is transmitted to a cloud platform or a monitoring center after data standardization; if the voltage rise rate of the DC bus belongs to the voltage rise rate reference interval, the actual internal resistance of the photovoltaic energy storage battery and an operation abnormality index of the photovoltaic energy storage battery are obtained, the actual internal resistance of the photovoltaic energy storage battery is compared with a reference internal resistance interval determined based on the operation abnormality index of the photovoltaic energy storage battery; if the actual internal resistance of the photovoltaic energy storage battery is smaller than the lower limit value of the reference internal resistance interval, any current in the photovoltaic energy storage battery is prohibited, and the operation data of the photovoltaic energy storage battery is transmitted to a cloud platform or a monitoring center after data standardization; If the actual internal resistance of the photovoltaic energy storage battery belongs to the reference internal resistance interval, it is determined that the charging process of the photovoltaic energy storage battery is not intelligently controlled and managed; If the actual internal resistance of the photovoltaic energy storage battery is greater than the upper limit value of the reference internal resistance interval, the photovoltaic energy storage battery is in an abnormal aging state, and it is determined that the charging process of the photovoltaic energy storage battery is intelligently controlled and managed; At the same time, the duration of the photovoltaic energy storage battery in the abnormal aging state is updated, and if the duration is greater than or equal to the defined duration, a warning is given.

5. The intelligent management and protection system for photovoltaic energy storage cells as claimed in claim 4 wherein, The operation abnormality index of the photovoltaic energy storage battery is specifically analyzed as follows: The running state deviation of the photovoltaic energy storage battery is analyzed, that is, the operation abnormality index theoretical increment of the photovoltaic energy storage battery and the operation abnormality factor of the photovoltaic energy storage battery are obtained and coupled to obtain the operation abnormality index of the photovoltaic energy storage battery; The operation abnormality index of the photovoltaic energy storage battery is a comprehensive index for quantifying the aging state of the photovoltaic energy storage battery, which is the superposition result of the theoretical aging degree of the photovoltaic energy storage battery based on material characteristics and theoretical cycle attenuation law and the aging degree of the photovoltaic energy storage battery caused in the actual operation process; The operation abnormality factor of the photovoltaic energy storage battery is specifically analyzed as follows: The historical maximum capacity attenuation rate, the historical maximum capacity deviation rate, and the historical maximum temperature rise rate of the photovoltaic energy storage battery are extracted from the operation data of the photovoltaic energy storage battery; The normalized historical maximum capacity attenuation rate, the historical maximum capacity deviation rate, and the historical maximum temperature rise rate eliminate the incomparability caused by the dimension and numerical range differences of each parameter, so that the normalized parameters have the same weight calculation basis. On this basis, the additional aging degree quantification value of the photovoltaic energy storage battery in the actual operation process due to non-standard working conditions is further superimposed, and the normalized parameters and the additional aging degree quantification value are integrated and calculated through a preset weighting algorithm to finally obtain the operation abnormality factor of the photovoltaic energy storage battery which can comprehensively reflect the aging degree of the photovoltaic energy storage battery caused in the actual operation process.

6. The intelligent management and protection system for photovoltaic energy storage cells as claimed in claim 4 wherein, The intelligent control and management of the charging process of the photovoltaic energy storage battery is specifically managed as follows The temperature control threshold interval of the photovoltaic energy storage battery is tightened based on the operation abnormality index of the photovoltaic energy storage battery; During the charging process, if the photovoltaic energy storage battery has a temperature abnormality condition, the power of the photovoltaic energy storage battery is reduced based on the operation abnormality index of the photovoltaic energy storage battery. After the reduction is completed, if the temperature abnormality condition still exists, the photovoltaic energy storage battery terminates the current charging and discharging action; The temperature abnormality condition refers to that the duration of the temperature of the photovoltaic energy storage battery not belonging to the temperature control threshold interval is greater than or equal to the defined duration; After the pre-charging closing strategy is executed, the photovoltaic energy storage battery enters the constant current charging phase; The basic current change rate of the photovoltaic energy storage battery is obtained, the current change rate decrement is determined based on the operation abnormality index of the photovoltaic energy storage battery, and the current change rate of the photovoltaic energy storage battery is determined based on the basic current change rate of the photovoltaic energy storage battery and the current change rate decrement; The target current value of the constant current charging phase is corrected based on the operation abnormality index of the photovoltaic energy storage battery; The constant current charging process of the photovoltaic energy storage battery is monitored, and if abnormal charging conditions of the photovoltaic energy storage battery occur, the current change rate of the photovoltaic energy storage battery is reduced again; The charging current of the photovoltaic energy storage battery is gradually increased to the corrected target current value based on the current change rate of the photovoltaic energy storage battery, so that the photovoltaic energy storage battery is continuously charged according to the corrected target current value until the voltage of the photovoltaic energy storage battery increases to the corrected target voltage value; When the constant current charging end condition occurs, it indicates that the constant current charging phase ends, and the photovoltaic energy storage battery enters the constant voltage charging phase, so that the constant voltage charging process of the photovoltaic energy storage battery is monitored; The corrected target voltage value specifically refers to: when the charging current of the photovoltaic energy storage battery is increased to the corrected target current value, the first deviation factor of the photovoltaic energy storage battery is obtained and compared with the defined deviation factor, if the first deviation factor of the photovoltaic energy storage battery is greater than or equal to the defined deviation factor, the target voltage value is corrected based on the first deviation factor of the photovoltaic energy storage battery and the operation abnormality index of the photovoltaic energy storage battery; If the first deviation factor of the photovoltaic energy storage battery is less than the defined deviation factor, the target voltage value is corrected based on the operation abnormality index of the photovoltaic energy storage battery.

7. The intelligent management and protection system of photovoltaic energy storage cell according to claim 6, characterized in that, The constant voltage charging process of the photovoltaic energy storage battery is monitored, and the specific monitoring process is: The duration of the constant voltage monitoring period is determined based on the operation abnormality index of the photovoltaic energy storage battery; In the constant voltage monitoring period, the second deviation factor of the photovoltaic energy storage battery is obtained and compared with the defined deviation factor, if the second deviation factor of the photovoltaic energy storage battery is greater than or equal to the defined deviation factor, the tail current size is corrected based on the second deviation factor of the photovoltaic energy storage battery and the operation abnormality index of the photovoltaic energy storage battery, and the determination duration of the tail current is reduced; If the second deviation factor of the photovoltaic energy storage battery is less than the defined deviation factor, the tail current size is corrected based on the operation abnormality index of the photovoltaic energy storage battery, and the determination duration of the tail current is reduced; When the constant voltage charging end condition occurs, it indicates that the constant current charging phase ends, and the photovoltaic energy storage battery enters the floating charging phase of the photovoltaic energy storage battery, and the photovoltaic energy storage battery is continuously charged according to the corrected tail current; At the same time, the parameters of the photovoltaic energy storage battery are reinitialized.

8. The intelligent management and protection system for photovoltaic energy storage cells according to claim 7, characterized in that, The reinitialization process of the parameters of the photovoltaic energy storage battery is: Based on the first deviation factor of the photovoltaic energy storage battery and the second deviation factor of the photovoltaic energy storage battery, the total deviation factor of the photovoltaic energy storage battery is obtained and compared with the defined total deviation factor; If the total deviation factor of the photovoltaic energy storage battery is greater than the defined total deviation factor, the operation abnormality index additional increment is increased based on the total deviation factor of the photovoltaic energy storage battery, so as to reinitialize the operation abnormality index additional increment of the photovoltaic energy storage battery, and update the charging frequency, so as to reinitialize the operation abnormality index theoretical increment of the photovoltaic energy storage battery; If the total deviation factor of the photovoltaic energy storage battery is greater than the defined total deviation factor, the charging frequency is updated, so as to reinitialize the operation abnormality index theoretical increment of the photovoltaic energy storage battery.

9. A method for intelligent management and protection of a photovoltaic energy storage cell, the method being used in the system for intelligent management and protection of a photovoltaic energy storage cell according to any one of claims 1-8, characterized in that, The method comprises: Through a communication module built in the inverter, operation data of the photovoltaic energy storage battery are collected, and remote data transmission is performed, so that the operation state of the photovoltaic energy storage battery is monitored in real time; Based on the operation data of the photovoltaic energy storage battery, it is determined whether the photovoltaic energy storage battery is in a charging state, if yes, the deviation degree of the operation state of the photovoltaic energy storage battery is analyzed, so as to determine whether to intelligently control and manage the charging process of the photovoltaic energy storage battery, if not, the operation data of the photovoltaic energy storage battery are continuously collected; When the island signal is detected, island protection is realized, and the photovoltaic energy storage battery cooperates with the inverter to enter an off-grid mode to continuously supply power to the local load.

10. An intelligent management and protection device for photovoltaic energy storage cells, characterized in that, The device comprises: a processor; a transceiver; a memory, wherein computer readable instructions are stored on the memory, and the computer readable instructions are executed by the processor to realize the intelligent management and protection system of the photovoltaic energy storage battery according to any one of claims 1 to 8.

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