Solar street lamp energy storage management device and method

Abstract

The invention discloses a solar street lamp energy storage management device which comprises a first-stage power pre-storage module which is composed of two sets of energy pre-storage units connected in parallel, a second-stage power storage module which is composed of at least two sets of energy storage units connected in parallel, and a third-stage power storage module which is composed of at least two sets of energy storage units connected in parallel, the positive electrodes of the energy storage units are connected to the same bus, and the negative electrodes of the energy storage units are connected to the intelligent charging and discharging optimization module, the electric energy detection module and the data analysis and fault decision-making module through independent controllable power-on valves, and the intelligent charging and discharging optimization module is composed of a control unit and a data analysis unit. The system is composed of an optimization decision unit, a primary control module and a secondary control module, detects electrical data of each energy storage unit in real time, and forms a comprehensive performance evaluation coefficient and a residual life value, thereby screening a fault energy storage unit, isolating the fault energy storage unit, dynamically selecting the optimal energy storage unit to execute a charging and discharging task, and effectively prolonging the service life of the energy storage unit.

Description

Technical Field

[0001] The present invention relates to the field of energy storage management for solar street lamps, and more specifically, to an energy storage management device and method for solar street lamps. Background Art

[0002] Solar energy, as a clean energy source, has been widely used in street lamp lighting systems. Existing solar street lamp systems usually include solar panels, storage batteries, controllers, and lighting lamps. However, existing solar street lamp systems have deficiencies in power storage and utilization efficiency. In particular, the power output of solar panels is greatly affected by light fluctuations, and direct charging causes storage batteries to frequently withstand surge currents and inefficient charging, accelerating the aging of the electrodes of the energy storage unit; in terms of battery life management, there is a lack of pretreatment and intelligent management of electric energy, resulting in shortened battery life and low system efficiency. Summary of the Invention

[0003] In view of this situation, we propose an energy storage management device and method for solar street lamps to solve the above deficiencies existing in existing solar street lamp systems.

[0004] 1. Technical Solution

[0005] An energy storage management device for solar street lamps includes:

[0006] A primary pre-storage power module, which is composed of two groups of parallel pre-storage units, and each group of pre-storage units is a hybrid structure including a supercapacitor unit and a lithium-ion battery unit;

[0007] A secondary storage power module, which is composed of at least two groups of parallel energy storage units. The positive electrodes of each energy storage unit are commonly connected to the same bus, and the negative electrodes are connected to an intelligent charge and discharge optimization module through independently controllable power-on valves;

[0009] An electric energy detection module, which is connected in parallel with each energy storage unit in the secondary storage power module and is used for real-time detection of the electrical performance data of each energy storage unit;

[0010] A data analysis and fault decision-making module, which is composed of a control unit and a data analysis unit. The data analysis unit comprehensively analyzes the detection data of the electric energy detection module. When the comprehensive analysis parameter of the electrical performance of any energy storage unit deviates from the threshold, the control unit controls the corresponding power-on valve to disconnect, isolating the faulty energy storage unit from other energy storage units;

[0011] The intelligent charge and discharge optimization module consists of an optimization decision unit, a primary control module, and a secondary control module. Based on the real-time monitoring data of each energy storage unit and its comprehensive analysis by the data analysis unit, combined with the historical charge and discharge times and the predicted remaining life values of each energy storage unit, it dynamically selects the optimal energy storage unit to execute the charge and discharge tasks, and real-time detects the input voltage of the solar power generation module and the voltage of the lithium-ion battery unit inside the primary pre-storage module, and dynamically controls the optimal charge and discharge method of the primary pre-storage module;

[0012] The emergency mains power supply module is connected to the mains power grid and is connected in parallel with the secondary energy storage module.

[0013] Preferably, the energy storage unit is a lithium iron phosphate battery pack, the capacity of a single energy storage unit is 20 - 50 Ah, the capacity deviation between energy storage units is ≤ 2%, and the power-on valve is an IGBT-driven solid-state switch with a response time < 100 μs.

[0014] Preferably, the electrical performance data items of the electrical energy detection module include:

[0015] The slope deviation of the charge and discharge curve;

[0016] The temperature rise rate;

[0017] The internal resistance change rate;

[0018] The voltage consistency difference rate.

[0019] Preferably, the primary control module includes a primary front-end conversion unit and a primary back-end conversion unit. The primary front-end conversion unit is used for the charge conversion between the two groups of parallel pre-storage units, and the primary back-end conversion unit is used for the discharge conversion of the two groups of parallel pre-storage units, and the response time of the primary back-end conversion unit < 100 μs.

[0020] Preferably, the control unit is electrically connected to the power-on valve, the secondary control module is electrically connected to the power-on valve, and the priority of the control signal of the control unit is higher than that of the control signal of the secondary control module.

[0021] Preferably, the method for a solar street lamp energy storage management device includes the following steps:

[0022] S001. Preset the charging threshold and the charge and discharge curve, and the primary pre-storage module receives the unstable electrical energy from the solar power generation module;

[0023] S002. When the input voltage reaches the first threshold K1, the primary front-end conversion unit is turned on, and a group of the pre-energy storage unit's supercapacitor units start charging. When the voltage of the supercapacitor units reaches the second threshold K2, the lithium-ion battery units in the same group start charging. When the voltage of the lithium-ion battery units reaches the third threshold K3, the primary back-end conversion unit is turned on, and the secondary energy storage module starts charging;

[0024] S003. The power detection module detects the electrical performance data of each energy storage unit of the secondary energy storage module in real time and transmits the data to the data analysis and fault decision-making module. The data analysis and fault decision-making module comprehensively analyzes the detected data to generate a comprehensive performance evaluation coefficient Y(i, j) and a remaining life L(i, j);

[0025] The calculation formula of the comprehensive performance evaluation coefficient Y(i, j) is:

[0026]

[0027] In the formula, Ki is the charge and discharge curve slope of the energy storage unit j at time i, K1 is the preset charge and discharge curve slope of the energy storage unit, Ti is the temperature rise rate of the energy storage unit j at time i, Ri is the internal resistance change rate of the energy storage unit j at time i, ΔV is the difference rate between the maximum and minimum monomer voltages of the energy storage unit at time i, and S1, S2, S3, S4 are preset proportionality coefficients, and S1 = 0.32, S2 = 0.2, S3 = 0.32, S4 = 0.2;

[0028] The formula for the remaining life L(i, j) is:

[0029] L(i, j) = L i -α×N i -β×ΔR i ,

[0030] In the formula, α is a fixed coefficient, and α = 0.05, β is the attenuation coefficient of the energy storage unit j, and β = 0.1, Ni is the cumulative number of charge and discharge cycles of the energy storage unit j at time i, ΔRi is the internal resistance change rate of the energy storage unit j at time i, and the initial life L0 is set according to the factory calibration value of the energy storage unit;

[0031] S004. Compare the comprehensive performance evaluation coefficient Y(i, j) with the preset threshold H1. When Y(i, j) ≥ H1, it is determined that the energy storage unit is a faulty energy storage unit, and the control unit controls the corresponding power-on valve to disconnect, physically isolating the faulty energy storage unit from other energy storage units;

[0032] S005. The optimization decision-making unit sorts according to the cumulative cycle times Nj and the remaining life L(i, j) of each energy storage unit, with the priority P = L(i, j) / (Nj + 1), and dynamically selects the optimal energy storage unit to perform the charge and discharge tasks through the secondary control module;

[0033] S006. When the number of faulty energy storage units exceeds 85% of the total number of energy storage units, or when the stored power of the secondary energy storage module fails to reach 15% of the total stored power for 24 consecutive hours, the emergency mains power supply module automatically switches to the mains power grid to supply power to the entire system.

[0034] Preferably, step S002 includes the following steps:

[0035] S201. Real-time detect the input voltage of the solar power generation module and the voltage of the lithium-ion battery unit inside the primary pre-energy storage module. When the input voltage reaches the first threshold K1, the primary front-end conversion unit is activated;

[0036] S202. Compare the voltages of the lithium-ion battery units of the two groups of pre-energy storage units in the primary pre-energy storage module. The primary front-end conversion unit selects the pre-energy storage unit with the smaller voltage value to connect, and this group of supercapacitor units starts to charge. When the voltage of the supercapacitor units reaches the second threshold K2, the lithium-ion battery units of the same group start to charge;

[0037] S203. When the voltage of any one of the two groups of lithium-ion battery units reaches the third threshold K3, the primary back-end conversion unit connects to it, and the secondary energy storage module starts to charge;

[0038] S204. When the voltage of the lithium-ion battery unit connected to the primary back-end conversion unit is equal to the second threshold K2, and the voltage of the other group of lithium-ion battery units is greater than the second threshold K2, the connection of the primary back-end conversion unit to the two groups of lithium-ion battery units is switched;

[0039] S205. When the voltage of the lithium-ion battery unit connected to the primary back-end conversion unit is equal to the second threshold K2, and the voltage of the other group of lithium-ion battery units is not greater than the second threshold K2, the connection of the primary back-end conversion unit to the two groups of lithium-ion battery units is disconnected.

[0040] Preferably, in step S002, the threshold K1 = 0.2V, the threshold K2 = 12V, and the threshold K3 = 24V.

[0041] 2. Beneficial effects

[0042] Compared with the existing solar street lamp system, the beneficial effects of the present invention are as follows:

[0043]

[0044] ​(1) The present invention breaks through the traditional single-capacitor buffering solution by setting up a primary pre-charging energy storage module and a secondary pre-charging energy storage module with a supercapacitor unit and a lithium-ion battery unit structure, avoiding the frequent and inefficient charging that accelerates the aging of the electrodes of the energy storage unit due to surge fluctuations, while taking into account both transient response and continuous energy storage requirements.

[0045] (2) The present invention forms a comprehensive performance evaluation coefficient and remaining life value by setting up at least two groups of parallel energy storage units to form a secondary pre-charging energy storage module, cooperating with an electric energy detection module, a data analysis and fault decision-making module, and an intelligent charge and discharge optimization module to detect the electrical data of each energy storage unit in real time, so as to screen and isolate faulty energy storage units and dynamically select the optimal energy storage unit to perform charge and discharge tasks, effectively extending the life of the energy storage unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the overall structure system of the present invention;

[0047] Figure 2 It is a flowchart of the working process of the data analysis and fault decision-making module of the present invention;

[0048] Figure 3 It is a flowchart of the working process of the intelligent charge and discharge optimization module of the present invention;

[0049] Figure 4 It is a flowchart of the energy storage management method of the present invention;

[0050] Figure 5 It is a flowchart of step S002 of the energy storage management method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Embodiment 1:

[0053] Please refer to Figures 1 - 5 , a solar street lamp energy storage management device, including:

[0054] A primary pre-charging energy storage module, which is composed of two groups of parallel pre-energy storage units, and each group of pre-energy storage units is a hybrid structure including a supercapacitor unit and a lithium-ion battery unit;

[0055] A secondary energy storage module, which is composed of at least two groups of parallel energy storage units, the positive electrodes of each energy storage unit are commonly connected to the same bus, and the negative electrodes are connected to the intelligent charge and discharge optimization module through independently controllable power-on valves;

[0057] The electric energy detection module is connected in parallel with each energy storage unit in the secondary energy storage module and is used for real-time detection of the electrical performance data of each energy storage unit;

[0058] The data analysis and fault decision-making module consists of a control unit and a data analysis unit. The data analysis unit comprehensively analyzes the detection data of the electric energy detection module. When the comprehensive analysis parameter of the electrical performance of any energy storage unit deviates from the threshold, the control unit controls the corresponding

[0059] energizing valve to disconnect and isolate the faulty energy storage unit from other energy storage units;

[0060] The intelligent charge and discharge optimization module consists of an optimization decision-making unit, a primary control module and a secondary control module. Based on the real-time monitoring data of each energy storage unit and its comprehensive analysis by the data analysis unit, combined with the historical charge and discharge times and the predicted remaining life values of each energy storage unit, it dynamically selects the optimal energy storage unit to perform the charge and discharge tasks, and real-time detects the input voltage of the solar power generation module and the voltage of the lithium-ion battery unit inside the primary pre-energy storage module, and dynamically controls the optimal charge and discharge method of the primary pre-energy storage module;

[0061] The mains emergency power supply module is connected to the mains power grid and is connected in parallel with the secondary energy storage module.

[0062] The energy storage unit is a lithium iron phosphate battery pack, the capacity of a single energy storage unit is 20 - 50 Ah, the capacity deviation between energy storage units ≤ 2%, and the energizing valve is an IGBT-driven solid-state switch with a response time < 100 μs.

[0063] The electrical performance data items of the electric energy detection module include:

[0064] The slope deviation of the charge and discharge curve;

[0065] The temperature rise rate;

[0066] The internal resistance change rate;

[0067] The voltage consistency difference rate.

[0068] The primary control module includes a primary front-end conversion unit and a primary back-end conversion unit. The primary front-end conversion unit is used for the charge conversion between the two groups of parallel pre-energy storage units, and the primary back-end conversion unit is used for the discharge conversion of the two groups of parallel pre-energy storage units, and the response time of the primary back-end conversion unit < 100 μs.

[0069] The control unit is electrically connected to the energizing valve, and the secondary control module is electrically connected to the energizing valve, and the priority of the control signal of the control unit is higher than the priority of the control signal of the secondary control module.

[0070] The method of a solar street lamp energy storage management device includes the following steps:

[0071] S001. Preset the charging threshold and charge-discharge curve. The primary pre-storage module receives the unstable electric energy from the solar power generation component;

[0072] S002. When the input voltage reaches the first threshold K1, the primary front-end conversion unit is turned on, and a group of the pre-storage unit supercapacitor units start to charge. When the voltage of the supercapacitor unit reaches the second threshold K2, the lithium-ion battery unit in the same group starts to charge. When the voltage of the lithium-ion battery unit reaches the third threshold K3, the primary back-end conversion unit is turned on, and the secondary energy storage module starts to charge;

[0073] S003. The electric energy detection module detects the electrical performance data of each energy storage unit of the secondary energy storage module in real time and transmits the data to the data analysis and fault decision-making module. The data analysis and fault decision-making module comprehensively analyzes the detected data to generate a comprehensive performance evaluation coefficient Y(i, j) and a remaining life L(i, j);

[0074] The calculation formula of the comprehensive performance evaluation coefficient Y(i, j) is:

[0075]

[0076] In the formula, Ki is the charge-discharge curve slope of the energy storage unit j at time i, K1 is the preset charge-discharge curve slope of the energy storage unit, Ti is the temperature rise rate of the energy storage unit j at time i, Ri is the internal resistance change rate of the energy storage unit j at time i, ΔV is the difference rate between the maximum and minimum monomer voltages of the energy storage unit at time i, S1, S2, S3, S4 are preset proportionality coefficients, and S1 = 0.32,

[0077] S2 = 0.2, S3 = 0.32, S4 = 0.2;

[0078] The formula for the remaining life L(i, j) is:

[0079] L(i, j) = L i -α×N i -β×ΔR i ,

[0080] In the formula, α is a fixed coefficient, and α = 0.05, β is the attenuation coefficient of the energy storage unit j, and β = 0.1, Ni is the cumulative cyclic charge-discharge times of the energy storage unit j at time i, ΔRi is the internal resistance change rate of the energy storage unit j at time i, and the initial life L0 is set according to the factory calibration value of the energy storage unit;

[0081] S004. Compare the comprehensive performance evaluation coefficient Y(i, j) with a preset threshold H1. When Y(i, j) ≥ H1, it is determined that the energy storage unit is a faulty energy storage unit. The control unit controls the corresponding power-on valve to disconnect, physically isolating the faulty energy storage unit from other energy storage units.

[0082] S005. The optimization decision-making unit sorts according to the cumulative cycle times N of each energy storage unit j and the remaining life L(i, j), with the priority P = L(i, j) / (N j +1), and dynamically selects the optimal energy storage unit to perform the charge and discharge tasks through the secondary control module.

[0083] S006. When the number of faulty energy storage units exceeds 85% of the total number of energy storage units, or the stored power of the secondary energy storage module has not reached 15% of the total stored power for 24 consecutive hours, the emergency power supply module automatically switches to the municipal power grid to supply power to the entire system.

[0084] Step S002 includes the following steps:

[0085] S201. Real-time detect the input voltage of the solar power generation module and the voltage of the lithium-ion battery unit inside the primary pre-energy storage module. When the input voltage reaches the first threshold K1, the primary front-end conversion unit is activated.

[0086] S202. Compare the voltages of the lithium-ion battery units in the two pre-energy storage units in the primary pre-energy storage module. The primary front-end conversion unit selects the pre-energy storage unit with the smaller voltage value to connect. The supercapacitor unit in this group starts charging. When the voltage of the supercapacitor unit reaches the second threshold K2, the lithium-ion battery unit in the same group starts charging.

[0087] S203. When the voltage of any one of the two groups of lithium-ion battery units reaches the third threshold K3, the primary back-end conversion unit connects to it, and the secondary energy storage module starts charging.

[0088] S204. When the voltage of the lithium-ion battery unit connected to the primary back-end conversion unit is equal to the second threshold K2, and the voltage of the other group of lithium-ion battery units is greater than the second threshold K2, the connection of the primary back-end conversion unit to the two groups of lithium-ion battery units is switched.

[0089] S205. When the voltage of the lithium-ion battery unit connected to the primary back-end conversion unit is equal to the second threshold K2, and the voltage of the other group of lithium-ion battery units is not greater than the second threshold K2, the connection of the primary back-end conversion unit to the two groups of lithium-ion battery units is disconnected.

[0090] In step S002, the threshold K1 = 0.2V, the threshold K2 = 12V, and the threshold K3 = 24V.

[0091] The above are only the preferred specific embodiments of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A solar street lamp energy storage management device, characterized in that, including: A primary pre - energy - storage module, which is composed of two groups of parallel - connected pre - energy - storage units. Each group of pre - energy - storage units is a hybrid structure including a super - capacitor unit and a lithium - ion battery unit; A secondary energy - storage module, which is composed of at least two groups of parallel - connected energy - storage units. The positive electrodes of each energy - storage unit are commonly connected to the same bus, and the negative electrodes are connected to the intelligent charge - discharge optimization module through independently controllable power - on valves; An electric - energy detection module, which is connected in parallel with each energy - storage unit in the secondary energy - storage module and is used for real - time detection of the electrical performance data of each energy - storage unit; A data - analysis and fault - decision - making module, which is composed of a control unit and a data - analysis unit. The data - analysis unit comprehensively analyzes the detection data of the electric - energy detection module. When the comprehensive - analysis parameter of the electrical performance of any energy - storage unit deviates from the threshold value, the control unit controls the corresponding power - on valve to disconnect, isolating the faulty energy - storage unit from other energy - storage units; An intelligent charge - discharge optimization module, which is composed of an optimization - decision unit, a primary control module, and a secondary control module. Based on the real - time monitoring data of each energy - storage unit and its comprehensive analysis by the data - analysis unit, combined with the historical charge - discharge times and the predicted remaining life values of each energy - storage unit, it dynamically selects the optimal energy - storage unit to execute the charge - discharge task, and real - time detects the input voltage of the solar power generation module and the voltage of the lithium - ion battery unit inside the primary pre - energy - storage module, dynamically controlling the optimal charge - discharge method of the primary pre - energy - storage module; An emergency mains - power - supply module, which is connected to the municipal power grid and is connected in parallel with the secondary energy - storage module.

2. The energy storage management device for a solar street lamp according to claim 1, characterized in that The energy - storage unit is a lithium iron phosphate battery pack. The capacity of a single energy - storage unit is 20 - 50 Ah, the capacity deviation between energy - storage units is ≤2%, the power - on valve is an IGBT - driven solid - state switch, and the response time < 100 μs.

3. The energy storage management device for a solar street lamp according to claim 1, wherein The electrical - performance data items of the electric - energy detection module include: The slope deviation of the charge - discharge curve; The temperature - rise rate; The internal - resistance change rate; The voltage - consistency difference rate.

4. A solar street lamp energy storage management device according to claim 1, characterized in that, The primary control module includes a primary front - end conversion unit and a primary back - end conversion unit. The primary front - end conversion unit is used for the charge conversion between the two groups of parallel - connected pre - energy - storage units, and the primary back - end conversion unit is used for the discharge conversion of the two groups of parallel - connected pre - energy - storage units, and the response time of the primary back - end conversion unit < 100 μs.

5. The energy storage management device of a solar street lamp according to claim 1, characterized in that, The control unit is electrically connected to the power - on valve, and the secondary control module is electrically connected to the power - on valve, and the priority of the control signal of the control unit is higher than the priority of the control signal of the secondary control module.

6. The method of an energy storage management device for a solar street lamp according to any one of claims 1-5, characterized in that: including the following steps: S001. Preset the charging threshold and the charge - discharge curve, and the primary pre - energy - storage module receives the unstable electric energy of the solar power generation module; S002. When the input voltage reaches the first threshold K1, the primary front - end conversion unit is turned on, and the super - capacitor unit of a group of the pre - energy - storage units starts to charge. When the voltage of the super - capacitor unit reaches the second threshold K2, the lithium - ion battery unit of the same group starts to charge. When the voltage of the lithium - ion battery unit reaches the third threshold K3, the primary back - end conversion unit is turned on, and the secondary energy - storage module starts to charge; S003. The electric energy detection module detects the electrical performance data of each energy storage unit of the secondary energy storage module in real time, and transmits the data to the data analysis and fault decision-making module. The data analysis and fault decision-making module comprehensively analyzes the detected data to generate a comprehensive performance evaluation coefficient Y(i, j) and a remaining life L(i, j). The calculation formula of the comprehensive performance evaluation coefficient Y(i, j) is as follows: In the formula, Ki is the charge and discharge curve slope of the energy storage unit j at time i, K1 is the preset charge and discharge curve slope of the energy storage unit, Ti is the temperature rise rate of the energy storage unit j at time i, Ri is the internal resistance change rate of the energy storage unit j at time i, ΔV is the difference rate between the maximum and minimum monomer voltages of the energy storage unit at time i, S1, S2, S3, and S4 are preset proportionality coefficients, and S1 = 0.32, S2 = 0.2, S3 = 0.32, S4 = 0.2; The formula for the remaining life L(i, j) is as follows: L(i, j) = L i -α × N i -β × ΔR i In the formula, α is a fixed coefficient, and α = 0.05, β is the attenuation coefficient of the energy storage unit j, and β = 0.1, Ni is the cumulative number of charge and discharge cycles of the energy storage unit j at time i, ΔRi is the internal resistance change rate of the energy storage unit j at time i, and the initial life L0 is set according to the factory calibration value of the energy storage unit; S004. Compare the comprehensive performance evaluation coefficient Y(i, j) with the preset threshold H1. When Y(i, j) ≥ H1, it is determined that the energy storage unit is a faulty energy storage unit. The control unit controls the corresponding power-on valve to disconnect, physically isolating the faulty energy storage unit from other energy storage units; S005. The optimization decision-making unit sorts according to the cumulative number of cycles Nj and the remaining life L(i, j) of each energy storage unit according to the priority P = L(i, j) / (Nj + 1), and dynamically selects the optimal energy storage unit through the secondary control module to perform the charge and discharge tasks; S006. When the number of faulty energy storage units exceeds 85% of the total number of energy storage units, or the stored power of the secondary energy storage module has not reached 15% of the total stored power for 24 consecutive hours, the emergency power supply module for the city power automatically switches to the city power grid to supply power to the entire system.

7. The method of a solar street lamp energy storage management device according to claim 6, characterized in that, Step S002 includes the following steps: S201. Detect the input voltage of the solar power generation module and the voltage of the lithium-ion battery unit inside the primary pre-energy storage module in real time. When the input voltage reaches the first threshold K1, the primary front-end conversion unit is started; S202. Compare the voltages of the two groups of pre-energy storage unit lithium-ion battery units in the primary pre-energy storage module. The primary front-end conversion unit selects the pre-energy storage unit with the smaller voltage value to connect. This group of supercapacitor units starts to charge. When the voltage of the supercapacitor units reaches the second threshold K2, the lithium-ion battery units in the same group start to charge; S203. When the voltage of any one of the two groups of lithium-ion battery units reaches the third threshold K3, the primary back-end conversion unit is connected to it, and the secondary energy storage module starts to charge; S204. When the voltage of the lithium-ion battery cell connected to the first-stage backend conversion unit is equal to the second threshold K2 and the voltage of the other group of lithium-ion battery cells is greater than the second threshold K2, the connection between the first-stage backend conversion unit and the two groups of lithium-ion battery cells is switched. S205. When the voltage of the lithium-ion battery cell connected to the first-stage backend conversion unit is equal to the second threshold K2 and the voltage of the other group of lithium-ion battery cells is not greater than the second threshold K2, the connection between the first-stage backend conversion unit and the two groups of lithium-ion battery cells is disconnected.

8. The method of an energy storage management device for a solar street lamp according to claim 6, characterized in that, In step S002, the threshold K1 = 0.2V, the threshold K2 = 12V, and the threshold K3 = 24V.

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