Overvoltage protection method, device and equipment for energy storage battery system

Abstract

The invention relates to an energy storage battery system overvoltage protection method, device and equipment, and relates to the technical field of energy storage, and the method comprises the steps: building a nonlinear equivalent circuit model of an energy storage battery system according to the characteristics of the energy storage battery system; simulating the transient process of the energy storage battery system by adopting a nonlinear equivalent circuit model; and obtaining the overvoltage waveform of each part of the energy storage battery system, and determining the insulation strength of the energy storage battery system and the parameters of the surge protection device according to the overvoltage waveform. Therefore, the overvoltage amplitude calculated through the model is closer to the actual overvoltage amplitude of the lightning current, and guidance can be provided for overvoltage insulation strength design of the energy storage battery and parameter selection of a surge protector.

Description

Technical Field

[0001] The present disclosure relates to the field of energy storage technology, and in particular to an overvoltage protection method, device, and equipment for an energy storage battery system. Background Art

[0002] Battery energy storage can temporarily store electricity from renewable energy sources (such as solar energy and wind energy) when there is excess power generation, and release it when there is insufficient power generation, playing the role of "peak shaving and valley filling", improving energy utilization efficiency and stability, and ensuring a reliable energy supply.

[0003] While current equivalent circuit models for energy storage batteries can describe their complex electrochemical processes, their structures are often overly complex. For example, some microscale battery models based on multi-physics coupling require enormous computational effort, making them difficult to apply in real-time engineering applications. While some simplified models offer fast computational speeds, they lack accuracy in describing the dynamic characteristics and nonlinear behavior of energy storage batteries. Overvoltage waveform parameters are imprecise, making them unable to provide precise guidance for protecting energy storage batteries from overvoltage conditions and failing to meet the demands of high-precision applications.

[0004] Therefore, how to design a nonlinear equivalent circuit calculation model for energy storage battery systems that is simple to calculate and has high accuracy to provide accurate guidance for overvoltage protection of energy storage batteries has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] In order to solve the above technical problems, the present disclosure provides an energy storage battery system overvoltage protection method, device and equipment for obtaining a more accurate energy storage system overvoltage waveform, thereby providing guidance for the overvoltage insulation strength design of the energy storage battery system and the parameter selection of the surge protection device.

[0006] In a first aspect, the present disclosure provides an energy storage battery system overvoltage protection method, comprising:

[0007] Establishing a nonlinear equivalent circuit model of the energy storage battery system according to the characteristics of the energy storage battery system;

[0008] Simulating the transient process of the energy storage battery system using the nonlinear equivalent circuit model;

[0009] An overvoltage waveform of the energy storage battery system is obtained, and the insulation strength of the energy storage battery system and parameters of a surge protection device are determined according to the overvoltage waveform.

[0010] Optionally, the nonlinear equivalent circuit model includes an equivalent ohmic internal resistance R0, a self-discharge resistance R s 、Ideal voltage source U OC , energy storage capacitor Cb , a first equivalent circuit and a second equivalent circuit, wherein the equivalent ohmic internal resistance R0 is connected in series with the self-discharge resistor Rs, and the ideal voltage source U OC , energy storage capacitor C b , the first equivalent circuit and the second equivalent circuit are connected in series, and are connected to the self-discharge resistor R s In parallel, the first equivalent circuit includes the electrochemical polarization internal resistance R e and electrochemical polarization capacitance C e The second equivalent circuit includes the concentration polarization internal resistance R in parallel. p and the concentration polarization capacitance C p ;

[0011] The method for simulating the transient process of the energy storage battery system using the nonlinear equivalent circuit model is: obtaining the parameters of each component in the nonlinear equivalent circuit model.

[0012] Optionally, the obtaining of the parameters of each component in the nonlinear equivalent circuit model includes: obtaining the ideal voltage source U in the open circuit state of the energy storage battery system. OC voltage value.

[0013] Optionally, the obtaining of the parameters of each component in the nonlinear equivalent circuit model includes: under constant current charging and discharging conditions, after charging for T1 time, obtaining the energy storage capacitor C by the ratio of the charge change ΔQ1 to the voltage change ΔU1 of the energy storage battery system. b capacitance value.

[0014] Optionally, obtaining the parameters of each component in the nonlinear equivalent circuit model includes: applying a step voltage ΔU2 to the energy storage battery system, measuring the charging current I2 of the energy storage battery system under the step voltage ΔU2, and the steady-state current ΔI2 after the step, wherein the time constant of the charging current I2 is τ; obtaining the electrochemical polarization internal resistance R by the ratio of the step voltage ΔU2 to the steady-state current ΔI2 e resistance value; through the time constant τ and the electrochemical polarization internal resistance R e The electrochemical polarization capacitance C is obtained by the ratio e capacitance value.

[0015] Optionally, obtaining the parameters of each component in the nonlinear equivalent circuit model includes: applying constant current pulses I31 and I32 of different amplitudes to the energy storage battery system, and recording voltage responses U31 and U32 of the energy storage battery system at different times and different excitation currents;

[0016] Substitute the lightning current and lightning voltage under simulation conditions into the equation:

[0017]

[0018] Among them, τ p is the concentration polarization time constant, t is time; according to the measured time-voltage-current relationship, the concentration polarization resistance R is obtained. p The resistance value;

[0019] Using formula C p =τ p / R p And the concentration polarization resistance R p Calculate the concentration polarization capacitance C p =τ p / R p capacitance value.

[0020] Optionally, obtaining the parameters of each component in the nonlinear equivalent circuit model includes: performing DC discharge on the energy storage battery system, recording the voltage change ΔU3 and the discharge current ΔI3 before and after discharge, and calculating the resistance value of the equivalent ohmic internal resistance R0 using the formula R0 = ΔU3 / ΔI3.

[0021] Optionally, the obtaining of the parameters of each component in the nonlinear equivalent circuit model includes: measuring the voltage value of the open circuit voltage U41 of the energy storage battery system in a fully charged state;

[0022] Measuring the open circuit voltage U42 of the energy storage battery system after standing for a period of time ΔT1 under a constant temperature state;

[0023] The self-discharge resistance R is calculated based on the voltage value obtained by the above measurement. S resistance value.

[0024] In a second aspect, the present disclosure provides an energy storage battery system overvoltage protection device, comprising:

[0025] Modeling module: used to establish a nonlinear equivalent circuit model of the energy storage battery system according to the characteristics of the energy storage battery system;

[0026] Acquisition module: used for simulating the transient process of the energy storage battery system by using the nonlinear equivalent circuit model;

[0027] Solution module: used to obtain the overvoltage waveforms of various parts of the energy storage battery system, and determine the insulation strength of the energy storage battery system and the parameters of the surge protection device according to the overvoltage waveforms.

[0028] In a third aspect, the present disclosure provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the energy storage battery system overvoltage protection method as described in the first aspect is implemented.

[0029] Compared with the existing technology, the technical solution provided by the present disclosure has the following advantages: by establishing a nonlinear equivalent calculation circuit model of the energy storage battery system, it can more accurately describe the electrical characteristics of the battery under different operating conditions such as overvoltage, including changes in open-circuit voltage, internal resistance, capacitance, etc., providing a basis for accurately analyzing the charging and discharging performance and energy efficiency of the energy storage battery, and further providing guidance for the overvoltage insulation strength design of the energy storage battery and the parameter selection of the surge protection device of the energy storage battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0031] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 Shown is a flow chart of an energy storage battery system overvoltage protection method provided by an embodiment of the present disclosure;

[0033] Figure 2 Schematic diagram of a nonlinear equivalent calculation circuit for overvoltage of an energy storage battery system provided by an embodiment of the present disclosure;

[0034] Figure 3 FIG2 is a schematic diagram of a module of an overvoltage protection device for an energy storage battery system provided by an embodiment of the present disclosure;

[0035] Figure 4 FIG2 is a schematic diagram of an overvoltage calculation model for an energy storage battery system provided by an embodiment of the present disclosure;

[0036] Figure 5 FIG2 shows an overvoltage waveform at both ends of an energy storage battery during a lightning current intrusion process provided by an embodiment of the present disclosure;

[0037] Figure 6 Shown is a structural diagram of a computer device provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned objectives, features and advantages of the embodiments of the present disclosure, the scheme of the embodiments of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present disclosure, but the embodiments of the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, not all of the embodiments.

[0040] Figure 1 FIG2 is a flow chart of an energy storage battery system overvoltage protection method provided by an embodiment of the present disclosure. Figure 2 The figure shows a schematic diagram of a nonlinear equivalent calculation circuit for overvoltage of an energy storage battery system provided by an embodiment of the present disclosure. Please refer to Figure 1 and Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10, comprising: step S1: establishing a nonlinear equivalent circuit model 100 of the energy storage battery system 10 based on the characteristics of the energy storage battery system 10; step S2: simulating a transient process of the energy storage battery system 10 using the nonlinear equivalent circuit model 100; and step S3: obtaining an overvoltage waveform of the energy storage battery system 10, and determining the insulation strength of the energy storage battery system 10 and parameters of a surge protection device based on the overvoltage waveform.

[0041] Specifically, in step S1, the energy storage battery system 10 is modeled according to a nonlinear equivalent circuit model 100, which includes multiple devices such as a voltage source, a capacitor, and a resistor. In step S2, under specific conditions, the transient process of the energy storage battery system 10 is simulated using devices such as an equivalent voltage source, a capacitor, and a resistor. Calculation and analysis are performed in simulation software to obtain overvoltage waveforms at various parts of the energy storage battery system 10, providing guidance for overvoltage protection of the energy storage system. This method is simple to calculate and has high accuracy. The simulated overvoltage amplitude is closer to the actual lightning voltage amplitude than the overvoltage amplitude of the conventional calculation model. In step S3, the overvoltage amplitude calculated according to the model can provide a reference for overvoltage protection of the energy storage battery system 10, such as increasing the insulation withstand strength of the energy storage battery system 10 or configuring a surge protection device with corresponding parameters at the outlet of the energy storage battery system 10 to reduce the impact of overvoltage on the energy storage battery system 10.

[0042] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. The nonlinear equivalent circuit model 100 includes an equivalent ohmic internal resistance R0, a self-discharge resistance R s 、Ideal voltage source UOC , energy storage capacitor C b , a first equivalent circuit 11 and a second equivalent circuit 12, wherein the equivalent ohmic internal resistance R0 and the self-discharge resistance R s In series, ideal voltage source U OC , energy storage capacitor C b , the first equivalent circuit 11 and the second equivalent circuit 12 are connected in series, and the self-discharge resistor R s In parallel, the first equivalent circuit 11 includes the electrochemical polarization internal resistance R e and electrochemical polarization capacitance C e The second equivalent circuit 12 includes a concentration polarization internal resistance R p and the concentration polarization capacitance C p ; The method of simulating the transient process of the energy storage battery system 10 using the nonlinear equivalent circuit model 100 is: obtaining the parameters of each component in the nonlinear equivalent circuit model 100.

[0043] Specifically, the nonlinear equivalent circuit 200 is connected to the positive and negative electrodes of the energy storage battery system 10; the ideal voltage source U OC Used to represent the open circuit voltage of the energy storage battery system 10, the energy storage capacitor C b It is used to describe the change in the open circuit voltage of the energy storage battery system 10 caused by discharge or charge. The equivalent ohmic internal resistance R0 is used to represent the resistance encountered by the current flowing through the battery when the energy storage battery system 10 is working. The self-discharge resistance R s Used to characterize the self-discharge phenomenon of the energy storage battery system 10, the electrochemical polarization internal resistance R e and electrochemical polarization capacitance C e The first equivalent circuit 11 simulates the electrochemical polarization of the energy storage battery system 10, and the concentration polarization internal resistance R p and concentration polarization capacitance C p The second equivalent circuit 12 simulates the concentration polarization of the energy storage battery system 10. In this way, by establishing the nonlinear equivalent circuit model 100 of the energy storage battery system 10, the ideal voltage source U OC , equivalent ohmic internal resistance R0, self-discharge resistance R s , energy storage capacitor C b , the first equivalent circuit 11 and the second equivalent circuit 12 simulate the transient process of the energy storage battery system 10. By obtaining the parameters of each component in the nonlinear equivalent circuit model 100, the internal change process of the energy storage battery system 10 during the transient process is visualized, and the overvoltage waveform of the energy storage battery system 10 is further obtained through calculation and analysis.

[0044] Please continue to refer to Figure 2The present disclosure provides an overvoltage protection method for an energy storage battery system 10. Obtaining the parameters of each component in the nonlinear equivalent circuit model 100 includes: obtaining the ideal voltage source U in the open circuit state of the energy storage battery system 10. OC voltage value.

[0045] Specifically, the ideal voltage source U OC The specific steps for obtaining the voltage value are as follows: put the energy storage battery system 10 in an open circuit state (i.e. not connected to any load or power source), let it stand for a long enough time (usually several hours or even longer to ensure that the battery reaches a stable state), and then use a high-precision voltmeter to directly measure the voltage between the positive and negative electrodes of the energy storage battery system 10. This voltage value is the open circuit voltage. In this way, the open circuit voltage U OC The potential difference between the positive and negative electrodes of the energy storage battery system 10 in the open circuit state (ie, when no current flows) is simulated to reflect the ability of the energy storage battery system 10 to convert chemical energy into electrical energy.

[0046] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. The parameters of each component in the nonlinear equivalent circuit model 100 are obtained by: under constant current charging and discharging conditions, after charging for T1 time, the energy storage capacitor C is obtained by the ratio of the charge change ΔQ1 to the voltage change ΔU1 of the energy storage battery system 10. b capacitance value.

[0047] Specifically, the energy storage capacitor C b The specific steps for obtaining the capacitance value are as follows: connect the energy storage battery system 10 to a constant current source, perform a constant current charge and discharge experiment on the energy storage battery system 10, measure the charge change ΔQ1 and voltage change ΔU1 of the energy storage battery system 10 after charging for T1 time, and the energy storage capacitor C b The capacitance value can be obtained from the formula C b =ΔQ1 / ΔU1. Thus, by using the energy storage capacitor C b Simulate the charge storage capacity of the energy storage battery system 10, the energy storage capacitor C b The capacitance value can reflect the amount of charge that the energy storage battery system 10 can store.

[0048] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. The method of obtaining parameters of each component in the nonlinear equivalent circuit model 100 includes: applying a step voltage ΔU2 to the energy storage battery system 10, measuring the charging current I2 of the energy storage battery system 10 under the step voltage ΔU2, and the steady-state current ΔI2 after the step, wherein the time constant of the charging current I2 is τ; and obtaining the electrochemical polarization internal resistance R by the ratio of the step voltage ΔU2 to the steady-state current ΔI2.e resistance value; through the time constant τ and the electrochemical polarization internal resistance R e The ratio of the electrochemical polarization capacitance C e capacitance value.

[0049] Specifically, the electrochemical polarization internal resistance R e and electrochemical polarization capacitance C e The acquisition method is as follows: applying a step voltage ΔU2 to the energy storage battery system 10, measuring the charging current I2 flowing through the energy storage battery system 10, and the steady-state current ΔI2 after the step. e =ΔU2 / ΔI2 The electrochemical polarization internal resistance R of the energy storage battery system 10 can be calculated e , further according to the time constant τ of the charging current I2, and the formula C e =τ / Re, the electrochemical polarization capacitance C can be calculated e The capacitance value can be obtained by connecting the electrochemical polarization resistance R e and electrochemical polarization capacitance C e , simulating the electrochemical polarization reaction process of the battery in the energy storage battery system 10.

[0050] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. Obtaining parameters of components in a nonlinear equivalent circuit model 100 includes applying constant current pulses I31 and I32 of different amplitudes to the energy storage battery system 10, recording voltage responses U31 and U32 of the energy storage battery system 10 at different times and with different excitation currents, and substituting the lightning current and lightning voltage under simulation conditions into the equation:

[0051]

[0052] Among them, τ p is the concentration polarization time constant, t is time; according to the measured time-voltage-current relationship, the concentration polarization resistance R can be obtained p The resistance value of p =τ p / R p And the concentration polarization resistance R p Calculate the concentration polarization capacitance C p capacitance value.

[0053] Specifically, constant current pulses I31 and I32 of different amplitudes, 4 / 10μs and 8 / 20μs, 5kA-10kA, were applied to the energy storage battery system 10, and the voltage responses U31 and U32 of the energy storage battery system 10 at different times and different excitation currents were recorded. Substituting the lightning current and lightning voltage in the experiment into equation (1), the concentration polarization resistance R was calculated.p The resistance value is further calculated according to the formula p The capacitance value can be set by the concentration polarization resistor R p and concentration polarization capacitance C p , simulating the concentration polarization reaction process of the battery in the energy storage battery system 10.

[0054] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. Obtaining parameters of components in a nonlinear equivalent circuit model 100 includes: performing a short-term DC discharge on the energy storage battery system 10, recording a voltage change ΔU3 and a discharge current ΔI3 before and after the discharge, and calculating the resistance value of an equivalent ohmic internal resistance R0 using the formula R0 = ΔU3 / ΔI3.

[0055] Specifically, the equivalent ohmic internal resistance R0 includes various ohmic resistances inside the energy storage battery system 10 , such as resistances of electrode materials, electrolytes, and diaphragms.

[0056] The specific method for obtaining the equivalent ohmic internal resistance R0 is to perform a short, high-current DC discharge on the energy storage battery system 10, record the voltage change ΔU3 and discharge current ΔI3 of the energy storage battery system 10 before and after the discharge, and calculate the resistance value of the equivalent ohmic internal resistance R0 based on the ratio of the change in voltage ΔU3 to the change in discharge current ΔI3. In this way, the internal resistance of the energy storage battery system 10 is represented by calculating the resistance value of the equivalent ohmic internal resistance R0.

[0057] Please continue to refer to Figure 2 The present disclosure provides an overvoltage protection method for an energy storage battery system 10. The method of obtaining the parameters of each component in the nonlinear equivalent circuit model 100 includes: measuring the voltage value of the open circuit voltage U41 of the energy storage battery system 10 in a fully charged state; measuring the voltage value of the open circuit voltage U42 of the energy storage battery system 10 after being left at a constant temperature for a period of ΔT1; and calculating the self-discharge resistance R according to the voltage values ​​obtained by the above measurements. S Resistance value

[0058]

[0059] Specifically, the self-discharge resistor R S It is used to characterize the self-discharge phenomenon of the energy storage battery system 10. Self-discharge refers to the process in which the battery gradually loses power due to various internal side reactions in the open circuit state.

[0060] Self-discharge resistor R SThe specific method for obtaining is as follows: after the energy storage battery system 10 is fully charged, use a high-precision voltmeter to measure the open circuit voltage U41 of the energy storage battery system 10, and record the voltage value at this time. The energy storage battery system 10 is placed in a constant temperature environment and left to stand for a period of time. For example, the constant temperature environment is 25°C, which is not limited in this disclosure. After a time ΔT1, the open circuit voltage U42 of the energy storage battery system 10 is measured again. The self-discharge resistance R is calculated according to formula (2): S The resistance value of the self-discharge resistor R S The resistance value represents the resistance value of the energy storage battery system 10 during the self-discharge process.

[0061] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied in a distributed scenario, where multiple devices cooperate with each other to complete the method. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the above method.

[0062] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0063] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present application also provides an energy storage battery system overvoltage protection device 300. Figure 3 FIG2 is a schematic diagram of a module of an energy storage battery system overvoltage protection device provided by an embodiment of the present disclosure. Figure 4 FIG2 is a schematic diagram of an overvoltage calculation model for an energy storage battery system provided by an embodiment of the present disclosure. Figure 5 The figure shows the overvoltage waveform at both ends of the energy storage battery during a lightning current intrusion process provided by an embodiment of the present disclosure. Please refer to Figures 1 to 5 The present disclosure provides an energy storage battery system overvoltage protection device 300, comprising: a modeling module 31 for establishing a nonlinear equivalent circuit model 100 of the energy storage battery system 10 based on the characteristics of the energy storage battery system 10; an acquisition module 32 for simulating the transient process of the energy storage battery system 10 using the nonlinear equivalent circuit model 100; and a solution module 33 for obtaining overvoltage waveforms at various parts of the energy storage battery system 10 and determining the insulation strength of the energy storage battery system 10 and parameters of the surge protection device based on the overvoltage waveforms.

[0064] Specifically, each module in the above-mentioned energy storage battery system overvoltage protection device 300 can be implemented in whole or in part by software, hardware, or a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of the above-mentioned modules. According to the nonlinear equivalent calculation circuit model 100 of the energy storage battery system 10 provided in the embodiment of the present disclosure, the energy storage battery system 10 lightning overvoltage simulation calculation model 200 is established, please refer to Figure 4 , lightning current invades the energy storage battery system 10 through the low-voltage power grid, load, and filter, wherein the low-voltage power grid provides a certain voltage support for the energy storage battery system 10 through parameters such as capacitance and inductance, helping to maintain the stability of the system voltage. In particular, the protection devices in the low-voltage power grid (such as circuit breakers, fuses, etc.) can quickly cut off the fault current when a fault such as a lightning strike occurs, thereby protecting the safety of the system; the load may include various electrical equipment, such as motors, lighting equipment, etc., which are not listed one by one in this disclosure. In the energy storage battery system 10, the switching action of the electrical equipment will generate harmonics. If these harmonics are not filtered out, they will have an adverse effect on the low-voltage power grid and the load. The filter can effectively filter out these harmonics, which helps to improve the power quality of the system. In transient processes such as lightning strikes, the filter can attenuate and suppress overvoltages through its impedance characteristics, thereby protecting the energy storage battery system 10 and the load from damage due to overvoltage. In an optional embodiment provided by the present disclosure, when a 10kA lightning current invades along the outlet end of the energy storage battery system 10, the energy storage battery system 10 lightning overvoltage simulation calculation model 200 can calculate the energy storage battery system 10 port overvoltage, such as Figure 5 As shown, Figure 5 The X axis of the overvoltage waveform represents time in seconds, and the Y axis represents voltage in kilovolts. Model calculations indicate that the maximum overvoltage amplitude in the overvoltage waveform at the energy storage battery system's 10 ports reaches 7 kV. Actual measurements show that the actual amplitude of the lightning current overvoltage at this location is 6.5 kV. This calculation result in the disclosed embodiment is more accurate than the 5 kV maximum overvoltage amplitude calculated using the equivalent resistance calculation model in related art.

[0065] According to the above calculation results, in order to prevent the energy storage battery system 10 from being damaged by lightning, it is necessary to set the insulation withstand strength of the energy storage battery in the energy storage battery system 10 to be above 20kV. Optionally, the insulation withstand strength of the energy storage battery can be set to 21kV, 22kV, 23kV, 24kV, 25kV, 26kV, 27kV... and so on, which is not limited in this disclosure; or, a surge protection device (Surge Protective Device, SPD) with a residual voltage value of less than 4.5kV is configured at the outlet end of the energy storage battery system 10. Optionally, the residual voltage value of the surge protection device can be 4kV, 3.5kV, 3kV, 2.5kV, 2kV, 1.5kV, 1kV, 0.5kV... and so on, which is not limited in this disclosure. A surge protection device is an electronic device that can provide safety protection, mainly used to limit overvoltage and discharge surge current. Surge protectors are typically connected in parallel with the protected equipment. When overvoltage occurs, they can shunt and limit voltage, preventing damage to the equipment caused by excessive current and voltage. Thus, through the nonlinear equivalent calculation circuit of the energy storage battery system 10 provided in this disclosure, the overvoltage amplitude calculated based on the lightning overvoltage simulation calculation model of the energy storage battery system 10 is closer to the actual amplitude of the lightning current overvoltage. The calculated overvoltage amplitude can provide guidance for selecting parameters for the insulation withstand strength of the energy storage battery and for selecting parameters for the surge protector at the outlet of the energy storage battery system 10.

[0066] For the convenience of description, the above device is described as being divided into various modules according to their functions. Of course, when implementing this application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0067] The device of the above embodiment is used to implement the corresponding overvoltage protection method of the energy storage battery system 10 in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0068] Figure 6 The figure shows a schematic diagram of the structure of a computer device provided by an embodiment of the present disclosure. Figure 6 The present disclosure provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the energy storage battery system overvoltage protection method as described above is implemented.

[0069] Specifically, in an optional embodiment provided by the present disclosure, a processor 1101 and a memory 1102 storing computer program instructions are included. The above-mentioned processor 1101 may include a central processing unit (CPU), or a specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application. The memory 1102 may include a large-capacity memory for information or instructions. By way of example and not limitation, the memory 1102 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a tape or a universal serial bus (USB) drive or a combination of two or more of these. Where appropriate, the memory 1102 may include a removable or non-removable (or fixed) medium. Where appropriate, the memory 1102 may be inside or outside the integrated gateway device. In a specific embodiment, the memory 1102 is a non-volatile solid-state memory. In a specific embodiment, the memory 1102 includes a read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM) or flash memory, or a combination of two or more of these.

[0070] The processor 1101 reads and executes the computer program instructions stored in the memory 1102 to perform the steps of the energy storage battery system overvoltage protection method provided in the embodiment of the present disclosure.

[0071] In one example, the computer device may further include a transceiver 1103 and a bus 1104. Figure 6 As shown, the processor 1101 , the memory 1102 and the transceiver 1103 are connected via a bus 1104 and communicate with each other.

[0072] The bus 1104 includes hardware, software, or both. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, the bus 1104 may include one or more buses. Although embodiments herein describe and illustrate a particular bus, this application contemplates any suitable bus or interconnect.

[0073] Through the above description of the implementation methods, those skilled in the art can clearly understand that the present disclosure can be implemented with the help of software and necessary general-purpose hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for enabling a computer cloud platform (which can be a personal computer, server, or network cloud platform, etc.) to execute the energy storage battery system overvoltage protection method provided by each embodiment of the present disclosure.

[0074] In summary, the present disclosure provides an energy storage battery system overvoltage protection method, device and equipment, including: establishing a nonlinear equivalent circuit model of the energy storage battery system according to the characteristics of the energy storage battery system; using the nonlinear equivalent circuit model to simulate the transient process of the energy storage battery system; obtaining the overvoltage waveform of each part of the energy storage battery system, and determining the insulation strength of the energy storage battery system and the parameters of the surge protection device according to the overvoltage waveform. By establishing the nonlinear equivalent circuit model of the energy storage battery system, the ideal voltage source U OC , equivalent ohmic internal resistance R0, self-discharge resistance R s , energy storage capacitor C b The first equivalent circuit and the second equivalent circuit simulate the transient process of the energy storage battery system, and further calculate and analyze the overvoltage waveforms of various parts of the energy storage battery system. OC Simulating the potential difference between the positive and negative electrodes of the energy storage battery system in the open circuit state can reflect the ability of the energy storage battery system to convert chemical energy into electrical energy. b Simulate the charge storage capacity of the energy storage battery system, the energy storage capacitor C b The capacitance value can reflect the amount of charge that the energy storage battery system can store. e and electrochemical polarization capacitance C e , simulate the electrochemical polarization reaction process of the battery in the energy storage battery system. Through the parallel concentration polarization resistor R p and concentration polarization capacitance C p , simulate the concentration polarization reaction process of the battery in the energy storage battery system. The internal resistance of the energy storage battery system is characterized by calculating the resistance value of the equivalent ohmic internal resistance R0. S The resistance value represents the resistance of the energy storage battery system during self-discharge. The nonlinear equivalent calculation circuit of the energy storage battery system provided by this disclosure allows the overvoltage amplitude calculated using the lightning overvoltage simulation calculation model of the energy storage battery system to more closely approximate the actual amplitude of the lightning current overvoltage. This calculated overvoltage amplitude can provide guidance for selecting parameters for the insulation withstand strength of the energy storage battery and for selecting parameters for the surge protector at the outlet of the energy storage battery system.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the above elements.

[0076] The foregoing are merely specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the foregoing embodiments, but is intended to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for overvoltage protection of an energy storage battery system, characterized in that: include: Establishing a nonlinear equivalent circuit model of the energy storage battery system according to the characteristics of the energy storage battery system; Simulating the transient process of the energy storage battery system using the nonlinear equivalent circuit model; An overvoltage waveform of the energy storage battery system is obtained, and the insulation strength of the energy storage battery system and parameters of a surge protection device are determined according to the overvoltage waveform.

2. The energy storage battery system overvoltage protection method according to claim 1, characterized in that: The nonlinear equivalent circuit model includes an equivalent ohmic internal resistance R0, a self-discharge resistance R s 、Ideal voltage source U OC , energy storage capacitor C b , a first equivalent circuit and a second equivalent circuit, wherein the equivalent ohmic internal resistance R0 and the self-discharge resistance R s In series, the ideal voltage source U OC , energy storage capacitor C b , the first equivalent circuit and the second equivalent circuit are connected in series, and are connected to the self-discharge resistor R s In parallel, the first equivalent circuit includes the electrochemical polarization internal resistance R e and electrochemical polarization capacitance C e The second equivalent circuit includes the concentration polarization internal resistance R in parallel. p and the concentration polarization capacitance C p ; The method for simulating the transient process of the energy storage battery system using the nonlinear equivalent circuit model is: obtaining the parameters of each component in the nonlinear equivalent circuit model.

3. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: Obtain the ideal voltage source U in the open circuit state of the energy storage battery system OC voltage value.

4. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: Under the condition of constant current charging and discharging, after charging for T1 time, the energy storage capacitor C is obtained by the ratio of the charge change ΔQ1 to the voltage change ΔU1 of the energy storage battery system. b capacitance value.

5. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: Applying a step voltage ΔU2 to the energy storage battery system, measuring the charging current I2 of the energy storage battery system under the step voltage ΔU2 and the steady-state current ΔI2 after the step, where the time constant of the charging current I2 is τ; The electrochemical polarization internal resistance R is obtained by the ratio of the step voltage ΔU2 to the steady-state current ΔI2. e resistance value; through the time constant τ and the electrochemical polarization internal resistance R e The electrochemical polarization capacitance C is obtained by the ratio e capacitance value.

6. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: Applying constant current pulses I31 and I32 of different amplitudes to the energy storage battery system, and recording voltage responses U31 and U32 of the energy storage battery system at different times and different excitation currents; Substitute the lightning current and lightning voltage under simulation conditions into the equation: Among them, τ p is the concentration polarization time constant, t is time; according to the measured time-voltage-current relationship, the concentration polarization resistance R is obtained. p The resistance value; Using formula C p =τ p / R p And the concentration polarization resistance R p Calculate the concentration polarization capacitance C p capacitance value.

7. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: The energy storage battery system is subjected to direct current discharge, and the voltage change ΔU3 and the discharge current ΔI3 before and after discharge are recorded. The resistance value of the equivalent ohmic internal resistance R0 is calculated using the formula R0=ΔU3 / ΔI3.

8. The energy storage battery system overvoltage protection method according to claim 2, characterized in that: The obtaining of parameters of each component in the nonlinear equivalent circuit model includes: Measuring the open circuit voltage U41 of the energy storage battery system in a fully charged state; Measuring the open circuit voltage U42 of the energy storage battery system after standing for a period of time ΔT1 under a constant temperature state; The self-discharge resistance R is calculated based on the voltage value obtained by the above measurement. S Resistance value 9. An energy storage battery system overvoltage protection device, characterized in that: include: Modeling module: used to establish a nonlinear equivalent circuit model of the energy storage battery system according to the characteristics of the energy storage battery system; Acquisition module: used for simulating the transient process of the energy storage battery system by using the nonlinear equivalent circuit model; Solving module: used to obtain the overvoltage waveform of the energy storage battery system, and determine the insulation strength of the energy storage battery system and the parameters of the surge protection device according to the overvoltage waveform.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the energy storage battery system overvoltage protection method described in any one of claims 1 to 8 is implemented.

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