Energy storage system charge / discharge control method, storage medium and energy storage system

Abstract

The present invention discloses a charge / discharge control method, storage medium and energy storage system for an energy storage system, the method comprising: obtaining the charge / discharge demand and the current SOC and voltage difference of each energy storage module, and sorting the current SOC of each energy storage module to obtain the current SOC sorting order of each energy storage module, obtaining the SOC correction difference of each energy storage module according to the voltage difference and working state of each energy storage module and the current SOC of each energy storage module, obtaining the comprehensive sorting order of each energy storage module according to the current SOC sorting order of each energy storage module and the SOC correction difference of each energy storage module, and controlling the charge / discharge power of each energy storage module according to the comprehensive sorting order and the charge / discharge demand. Through the above method, the consistency of each energy storage module in the energy storage system is improved, and unnecessary operation and maintenance costs caused by premature replacement of energy storage modules and the shutdown of the energy storage system caused by using energy storage modules in poor condition during operation can be prevented.

Description

Technical Field

[0001] The present invention belongs to the field of electric power technology, and specifically relates to a charge / discharge control method of an energy storage system, a storage medium and an energy storage system. Background Art

[0002] With the development of society, people's demand for electricity in daily production and life is constantly increasing, and the concentration of electricity consumption is becoming more and more obvious. This may cause insufficient power supply during peak hours such as daytime and evening, which will directly affect the stability and safety of the power grid. More and more places have to adopt extreme methods such as power outages to ensure the stable operation of the power grid, affecting people's production and life, and also bringing great inconvenience to people's lives and causing large economic losses.

[0003] The inventors have found through research that the existing energy storage system can improve the quality of power supply and enhance the stability of the power grid by shaving peaks and filling valleys. Compared with other energy storage methods, battery energy storage systems represented by lithium-ion and vanadium liquid batteries have the advantages of convenience, speed and high energy conversion rate, and therefore have received more and more attention. However, since the energy storage system will be charged and discharged according to actual needs, resulting in different working hours of each energy storage module in the energy storage system, there is a poor consistency among the energy storage modules in the energy storage system, which may cause the energy storage system to be in poor condition during operation, or require frequent battery replacement, resulting in increased maintenance costs for the energy storage system. Summary of the invention

[0004] The present invention provides a charge / discharge control method, a storage medium and an energy storage system for an energy storage system, so as to effectively alleviate the problem of poor consistency of energy storage modules and avoid the problem of increased maintenance cost of the energy storage system caused by frequent replacement of energy storage modules.

[0005] In a first aspect, the present invention provides a charge / discharge control method for an energy storage system, the method comprising:

[0006] Obtaining the charge / discharge demand and the current SOC and voltage difference of each energy storage module in the multiple energy storage modules included in the energy storage system, and sorting the current SOC of each of the energy storage modules to obtain the current SOC sorting order of each of the energy storage modules;

[0007] Obtaining a SOC correction difference of each energy storage module according to the voltage difference and working state of each energy storage module and the current SOC of each energy storage module;

[0008] Obtaining a comprehensive sorting order of each of the energy storage modules according to the current SOC sorting order of each of the energy storage modules and the SOC correction difference of each of the energy storage modules;

[0009] The charge / discharge power of each of the energy storage modules is controlled according to the comprehensive sorting order and the charge / discharge demand.

[0010] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, when the acquired charge / discharge demand is a discharge demand, the corresponding working state of each of the energy storage modules is a discharge state, and the SOC correction difference of each of the energy storage modules is obtained according to the voltage difference and working state of each of the energy storage modules and the current SOC of each of the energy storage modules, including:

[0011] When the working state of the energy storage module is the discharge state, for each of the energy storage modules, according to the discharge lower limit voltage of the energy storage module, the current minimum voltage of the battery in the energy storage module and the voltage difference of the energy storage module, a first preset calculation formula is used to calculate to obtain the discharge SOC coefficient of each of the energy storage modules, wherein the first preset calculation formula is (V L -V LL ) / V D , V L is the current minimum voltage of the battery in the energy storage module, V LL is the lower discharge limit voltage of the energy storage module, V D is the voltage difference of the energy storage module;

[0012] Obtaining the initial SOC under the discharge state corresponding to the discharge SOC coefficient of each of the energy storage modules;

[0013] The difference between the current SOC of each energy storage module and the initial SOC in the discharge state is used as the SOC correction difference of each energy storage module in the discharge state, and the SOC correction difference of each energy storage module in the discharge state is sorted to obtain the sorting order of the SOC correction difference of each energy storage module in the discharge state.

[0014] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand includes:

[0015] The demand of the energy storage module is calculated using a second preset calculation formula according to the discharge demand power in the discharge demand and the rated power of the energy storage module, wherein the second preset calculation formula is N=(Pload / Pe)+1, N is the demand of the energy storage module, Pload is the discharge demand power, and Pe is the rated power of the energy storage module;

[0016] When the demand N of the energy storage module is less than the number M of energy storage modules in the energy storage system, N energy storage modules are selected in descending order of the comprehensive sorting order so that the selected N energy storage modules output power, and the sum of the output powers of the N energy storage modules is the discharge demand power.

[0017] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, selecting N energy storage modules in descending order of the comprehensive ranking order so that the selected N energy storage modules output power includes:

[0018] Selecting N energy storage modules in descending order of the comprehensive ranking order, and summing the current SOCs of the selected N energy storage modules to obtain a total SOC;

[0019] According to the current SOC of each of the selected N energy storage modules, the total SOC and the required discharge power, a third preset calculation formula is used to calculate the calculated power corresponding to each of the N energy storage modules, so that each of the N energy storage modules outputs the corresponding calculated power, wherein the third preset calculation formula is: P k输出 =(SOC k / SumSOC)*Pload 放电 , SumSOC=∑SOC k , k=1,2...N,SOC k is the current SOC of the kth energy storage module, P k输出 is the output power of the Kth energy storage module, Pload 充电 The power required for discharge.

[0020] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, when the acquired charge / discharge demand is a charging demand, the working state corresponding to each of the energy storage modules is a charging state, and the SOC correction difference of each of the energy storage modules is obtained according to the voltage difference and working state of each of the energy storage modules and the current SOC of each of the energy storage modules, including:

[0021] When the working state of the energy storage module is the charging state, for each energy storage module, according to the charging upper limit voltage of the energy storage module, the current maximum voltage of the battery in the energy storage module and the voltage difference of the energy storage module, a fourth preset calculation formula is used to calculate to obtain the charging SOC coefficient of each energy storage module, wherein the fourth preset calculation formula is (V HL -V H ) / V D , V HL is the upper charging limit voltage of the energy storage module, V H is the current maximum voltage of the battery in the energy storage module, V D is the voltage difference of the energy storage module;

[0022] Obtaining the initial SOC in the charging state corresponding to the charging SOC coefficient of each of the energy storage modules;

[0023] The acquired difference between the initial SOC and the current SOC of each energy storage module in the charging state is used as the SOC correction difference of each energy storage module in the charging state.

[0024] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand includes:

[0025] Selecting the first J energy storage modules according to the order of the comprehensive ranking from low to high, and calculating the remaining power of each of the selected J energy storage modules;

[0026] According to the charging demand power in the charging demand, the maximum storage capacity and the remaining capacity of each of the selected J energy storage modules, the charging calculation power of each of the selected J energy storage modules is calculated according to the fifth preset calculation formula, so that each of the J energy storage modules is charged according to the charging calculation power, wherein the fifth preset calculation formula is: k输入 =((Q k电量 -Q k剩余 ) / SumQ)*Pload 充电 ,SumQ=∑(Q k电量 -Q k剩余 ), k=1,2...J,P k输入 Calculate the charging power of the Kth energy storage module, Q k电量 is the maximum storage capacity of the kth energy storage module, Q k剩余 is the remaining power of the Kth energy storage module, Pload 充电 Power is required for charging.

[0027] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, obtaining a comprehensive sorting order of each of the energy storage modules according to the current SOC sorting order of each of the energy storage modules and the SOC correction difference of each of the energy storage modules includes:

[0028] Sorting the energy storage modules according to the SOC correction difference to obtain a corrected SOC sorting order of the energy storage modules;

[0029] A weight calculation is performed according to the current SOC sorting order and the corrected SOC sorting order of each of the energy storage modules to obtain a comprehensive sorting order of each of the energy storage modules.

[0030] Optionally, in the above-mentioned charge / discharge control method of the energy storage system, the method further includes:

[0031] Acquire the historical charge / discharge efficiency of each of the energy storage modules, and sort the modules according to the historical charge / discharge efficiency to obtain a sorting order of the charging efficiency of each of the energy storage modules;

[0032] Predicting according to the corrected SOC of each energy storage module and the current SOC of each energy storage module to obtain the predicted SOC of each energy storage module, and sorting the predicted SOC of each energy storage module to obtain the predicted SOC sorting order of each energy storage module;

[0033] The comprehensive sorting order of each energy storage module is obtained according to the current SOC sorting order of each energy storage module and the SOC correction difference of each energy storage module, including:

[0034] Sorting the energy storage modules according to the SOC correction difference to obtain a corrected SOC sorting order of the energy storage modules;

[0035] A weight calculation is performed according to the current SOC sorting order, the corrected SOC sorting order, the charging efficiency sorting order and the predicted SOC sorting order of each of the energy storage modules to obtain a comprehensive sorting order of each of the energy storage modules.

[0036] In a second aspect, the present invention further provides a storage medium storing a computer program, wherein the computer program implements the above method when executed by one or more processors.

[0037] In a third aspect, the present invention provides an energy storage system, comprising a plurality of energy storage modules connected in parallel and a controller, wherein the controller is connected to each of the energy storage modules respectively, and the controller is used to execute the above method.

[0038] The present invention provides a charge / discharge control method, storage medium and energy storage system for an energy storage system, the method comprising: obtaining the charge / discharge demand and the current SOC and voltage difference of each energy storage module in a plurality of energy storage modules included in the energy storage system, and sorting the current SOC of each of the energy storage modules to obtain the current SOC sorting order of each of the energy storage modules, obtaining the SOC correction difference of each of the energy storage modules according to the voltage difference and working state of each of the energy storage modules and the current SOC of each of the energy storage modules, and sorting the energy storage modules according to the SOC correction difference to obtain the SOC correction difference sorting order of each of the energy storage modules, and sorting the energy storage modules according to the current SOC sorting order and the SOC correction difference sorting order of each of the energy storage modules. A comprehensive ranking order of each of the energy storage modules is obtained, and the charge / discharge power of each of the energy storage modules is controlled according to the comprehensive ranking order and the charge / discharge demand. By utilizing the comprehensive ranking order, a more realistic state of the current energy storage module can be reflected. Further, when the charge / discharge power of each of the energy storage modules is controlled by utilizing the comprehensive ranking order and the charge / discharge demand, the optimal energy storage module can be selected for charging / discharging, and excessive use of energy storage modules in poor state can be prevented, so that the consistency of energy storage modules in the energy storage system is better, the service life of the energy storage modules is extended, and unnecessary operation and maintenance costs caused by premature replacement of energy storage modules are prevented, and the energy storage system is shut down due to the use of energy storage modules in poor state during operation, and the load requirement cannot be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings are used to provide a further understanding of the technical solution of the present application or the prior art, and constitute a part of the specification. Among them, the accompanying drawings expressing the embodiments of the present application are used together with the embodiments of the present application to explain the technical solution of the present application, but do not constitute a limitation on the technical solution of the present application.

[0040] Figure 1 A schematic flow chart of a charge / discharge control method for an energy storage system provided in an embodiment of the present application.

[0041] Figure 2 for Figure 1 Schematic diagram of the process of step S120.

[0042] Figure 3 for Figure 1 Another flowchart diagram of step S120 in FIG.

[0043] Figure 4 Another schematic flow chart of a method for controlling charging / discharging of an energy storage system provided in an embodiment of the present application.

[0044] Figure 5 for Figure 1 Schematic diagram of the process of step S140.

[0045] Figure 6 for Figure 1 Another flowchart diagram of step S140 in FIG. DETAILED DESCRIPTION

[0046] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve corresponding technical effects can be fully understood and implemented accordingly. The embodiments of the present application and the various features in the embodiments can be combined with each other without conflict, and the technical solutions formed are all within the protection scope of the present invention.

[0047] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer such as a set of computer executable instructions. Also, although a logical sequence is shown in the flowchart, in some cases, the steps shown or described can be performed in a sequence different from that here.

[0048] First embodiment

[0049] See also Figure 1 This embodiment provides a charge / discharge control method for an energy storage system, which is applied to a controller in the energy storage system. The energy storage system also includes a plurality of energy storage modules connected in parallel, and the controller is electrically connected to each of the energy storage modules, respectively, to control the charge / discharge power of each of the energy storage modules.

[0050] When the controller controls the charge / discharge power of each of the energy storage modules, steps S110 to S140 are executed.

[0051] Step S110: acquiring the charge / discharge demand and the current SOC and voltage difference of each energy storage module in the multiple energy storage modules included in the energy storage system, and sorting the current SOC of each energy storage module to obtain the current SOC sorting order of each energy storage module.

[0052] Step S120: obtaining an SOC correction difference of each energy storage module according to the voltage difference and working state of each energy storage module and the current SOC of each energy storage module.

[0053] Step S130: obtaining a comprehensive sorting order of each of the energy storage modules according to the current SOC sorting order of each of the energy storage modules and the SOC correction difference of each of the energy storage modules.

[0054] Step S140: controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand.

[0055] By adopting the above steps S110 to S140, it is possible to obtain a comprehensive sorting order of each energy storage module according to the sorting order of the current SOC of each energy storage module in the energy storage system and the correction difference of each energy storage module, wherein the comprehensive sorting order more truly reflects the actual state of each energy storage module, so that when the comprehensive sorting order and the charge / discharge demand are used to control the charging / discharging of each energy storage module, the optimal energy storage module can be selected for charging and discharging, and the excessive use of energy storage modules in poor condition can be prevented, so as to make the consistency of energy storage modules in the energy storage system better and extend the service life of energy storage modules. In addition, it can also prevent unnecessary operation and maintenance costs caused by premature replacement of energy storage modules, and avoid the shutdown of the energy storage system caused by the use of energy storage modules in poor condition during operation, which in turn causes the failure to meet the load requirements.

[0056] In step S110, it should be noted that the charge / discharge demand includes a charging demand or a discharging demand, wherein when the charge / discharge demand includes a charging demand, the charging demand includes a charging demand power, and a method for obtaining the charging demand may be to obtain the charging power of a pre-stored energy storage system; when the charge / discharge demand includes a discharging demand, the energy storage system is usually connected to a load, and a specific method for obtaining the discharging demand may be to obtain the demand power of the load connected to the energy storage system, so as to use the demand power of the load as the discharge demand power of the discharging demand.

[0057] The current SOC of each of the energy storage modules may be obtained by: obtaining the total charge / discharge time, actual maximum capacity, nominal maximum capacity, and energy storage module attenuation life characteristic curve obtained through a large number of experiments, and calculating the attenuation degree and possible service life of the energy storage module, thereby obtaining the current SOC of each of the energy storage modules; or by: stimulating each energy storage module with alternating current of different frequencies, measuring the internal alternating current resistance of the energy storage module, and obtaining the current SOC value through an established calculation model; or by: calculating using the Kalman filter method, which is not specifically limited here and can be set according to actual needs.

[0058] The voltage difference of each energy storage module may be obtained by obtaining the voltage of each battery cell in each energy storage module, and taking the difference between the voltage of the battery cell with the largest voltage value and the voltage of the battery cell with the smallest voltage value in each of the energy storage modules as the voltage difference of the energy storage module. Alternatively, the voltage of each battery cell in the energy storage module may be sorted in descending order, and the voltage of the first two battery cells in the order may be summed and subtracted from the voltage of the last two battery cells in the order to obtain the average value to obtain the voltage difference of the energy storage module. The above process of obtaining the voltage difference of each energy storage module may be set according to actual needs and is not specifically limited here.

[0059] Sorting the current SOC of each of the energy storage modules may be to sort the current SOC of each of the energy storage modules in order from large to small, or may be to sort the current SOC of each of the energy storage modules in order from small to large. Optionally, in this embodiment, sorting the current SOC of each of the energy storage modules includes: sorting the current SOC of each of the energy storage modules in order from large to small to obtain the current sorting order of each of the energy storage modules.

[0060] In step S120, it should be noted that when the acquired charge / discharge demand is a charge demand, each energy storage module of the energy storage system should work in a charge state, and correspondingly, when the acquired charge / discharge demand is a discharge demand, each energy storage module of the energy storage system should work in a discharge state. Since the energy storage module has a standard SOC corresponding to different working states and different voltages when it just starts working (when each battery cell in the energy storage module is a battery cell used for the first time), as the battery in the energy storage module is used for a longer time, its performance changes, which in turn affects the current SOC value detected.

[0061] In order to obtain the correction difference of the energy storage module under different working states according to the working state of the energy storage module, in this embodiment, please combine Figure 2 When the acquired charging / discharging demand is a discharging demand, the step S120 includes:

[0062] Step S122a: When the working state of the energy storage module is the discharging state, for each of the energy storage modules, a first preset calculation formula is used to calculate according to the lower discharge limit voltage of the energy storage module, the current minimum voltage of the battery in the energy storage module and the voltage difference of the energy storage module to obtain the discharge SOC coefficient of each of the energy storage modules.

[0063] Among them, the first preset calculation formula is (V L -V LL ) / V D , V L is the current minimum voltage of the battery in the energy storage module, V LL is the lower discharge limit voltage of the energy storage module, V D is the voltage difference of the energy storage module.

[0064] The current lowest voltage of the battery in the energy storage module is the voltage of the battery with the lowest voltage among the voltages of the multiple batteries in the energy storage module in the current state.

[0065] Step S124a: obtaining the initial SOC in the discharge state corresponding to the discharge SOC coefficient of each of the energy storage modules.

[0066] Among them, the above-mentioned step S124a can be to obtain the initial SOC in the discharge state corresponding to the discharge SOC coefficient of each of the energy storage modules from a preset corresponding relationship table, wherein the preset corresponding relationship table includes multiple discharge SOC coefficients and the initial SOC in the discharge state corresponding to each discharge SOC coefficient.

[0067] Step S126a: taking the difference between the current SOC of each energy storage module and the initial SOC in the discharge state as the SOC correction difference of each energy storage module in the discharge state.

[0068] Through the above method steps, the SOC correction difference of the energy storage module in the discharge state can be accurately known, so as to facilitate the comprehensive ranking order of each energy storage module in the discharge state to be obtained according to the SOC correction difference of each energy storage module in the discharge state and the current SOC of each energy storage module.

[0069] Please combine Figure 3 When the acquired charging / discharging demand is a charging demand, the step S120 includes:

[0070] Step S122b: When the working state of the energy storage module is the charging state, for each energy storage module, according to the charging upper limit voltage of the energy storage module, the current maximum voltage of the battery in the energy storage module and the voltage difference of the energy storage module, a fourth preset calculation formula is used to calculate to obtain the charging SOC coefficient of each energy storage module.

[0071] Wherein, the fourth preset calculation formula is (V HL -V H ) / V D , V HL is the upper charging limit voltage of the energy storage module, V H is the current maximum voltage of the battery in the energy storage module, V D is the voltage difference of the energy storage module.

[0072] The current highest voltage of the battery in the energy storage module is the voltage of the battery with the highest voltage value among the voltages of the multiple batteries in the energy storage module.

[0073] Step S124b: obtaining the initial SOC in the charging state corresponding to the charging SOC coefficient of each of the energy storage modules.

[0074] Among them, the above-mentioned step S124b can be, obtaining the initial SOC under the charging state corresponding to the charging SOC coefficient of each of the energy storage modules from a preset corresponding relationship table, wherein the preset corresponding relationship table includes multiple charging SOC coefficients and the initial SOC under the charging state corresponding to each charging SOC coefficient.

[0075] Step S126b: taking the difference between the initial SOC and the current SOC of each energy storage module in the charging state obtained as the SOC correction difference of each energy storage module in the charging state.

[0076] Through the above method steps, the SOC correction difference of the energy storage module under charging state can be accurately known, so as to facilitate obtaining the comprehensive ranking order of each energy storage module under charging state according to the SOC correction difference of each energy storage module under charging state and the current SOC of each energy storage module.

[0077] The above step S130 may be: adjusting each current SOC in the current SOC sorting order according to the SOC correction difference (SOC correction difference in the charging state or SOC correction difference in the discharging state) of each of the energy storage modules, and sorting the adjusted SOC to obtain a comprehensive sorting order. For example, directly multiplying the SOC correction difference of each energy storage module by a set coefficient and then superimposing it with the current SOC of the energy storage module to obtain the corrected SOC of each energy storage module, and sorting the corrected SOC of each energy storage module to obtain a comprehensive sorting order. The above step S130 may also be to sort the SOC correction difference of each of the energy storage modules to obtain a corrected SOC sorting order, and perform weight calculation according to the corrected SOC sorting order and the current SOC sorting order to obtain the comprehensive sorting order of each of the energy storage modules.

[0078] Optionally, in this embodiment, step S130 includes:

[0079] The energy storage modules are sorted according to their SOC correction differences to obtain a corrected SOC sorting order of the energy storage modules, and weight calculation is performed according to the current SOC sorting order and the corrected SOC sorting order of the energy storage modules to obtain a comprehensive sorting order of the energy storage modules.

[0080] Through the above arrangement, the pressure difference of each energy storage module can be used to assist in calibrating the corresponding current SOC, so as to obtain a more realistic sorting order of the energy storage modules.

[0081] It should be noted that when performing weight calculation, it is necessary to assign different weights to the current SOC sorting order and the corrected SOC sorting order, and assign different weights to energy storage modules corresponding to different sorting numbers in the current SOC sorting order, and assign different weights to energy storage modules corresponding to different sorting numbers in the corrected SOC sorting order, so as to use the weight calculation formula to perform weight calculation on each of the energy storage modules to obtain the weight calculation result of each of the energy storage modules, and then sort the energy storage modules according to the weight calculation results to obtain a comprehensive sorting order of each of the energy storage modules.

[0082] The above-mentioned sorting according to the weight calculation results of each of the energy storage modules may specifically be sorting according to the weight calculation results of each of the energy storage modules in descending order to obtain a comprehensive sorting order of each of the energy storage modules.

[0083] Please combine Figure 4 To further make the comprehensive sorting order more reliable, in this embodiment, the method further includes step S150 and step S160.

[0084] Step S150: acquiring the historical charge / discharge efficiency of each of the energy storage modules, and sorting the modules according to the historical charge / discharge efficiency to obtain a sorting order of the charging efficiency of each of the energy storage modules.

[0085] Step S160: Predicting based on the corrected SOC of each energy storage module and the current SOC of each energy storage module to obtain the predicted SOC of each energy storage module, and sorting the predicted SOC of each energy storage module to obtain the predicted SOC sorting order of each energy storage module.

[0086] Step S130 can also obtain a comprehensive sorting order based on the charging efficiency sorting order obtained in the above step S150, the predicted SOC sorting order obtained in the above step S160, and the current SOC sorting order and the corrected SOC sorting order; that is, step S130 also includes step S132 and step S134.

[0087] Step S132: sorting the energy storage modules according to the corrected SOC differences to obtain a corrected SOC sorting order of the energy storage modules.

[0088] Step S134: performing weight calculation according to the current SOC sorting order, the corrected SOC sorting order, the charging efficiency sorting order and the predicted SOC sorting order of each of the energy storage modules to obtain a comprehensive sorting order of each of the energy storage modules.

[0089] Please refer to Table 1. Taking the energy storage system including three energy storage modules, namely module A, module B and module C as an example, and the current SOC ranking order, corrected SOC ranking order, charging efficiency ranking order and predicted SOC ranking of each energy storage module, the total ranking score and the new ranking obtained by weighting the above four ranking orders are shown in Table 1:

[0090]

[0091] Through the above settings, when only one energy storage module is needed for power supply, module B is selected for power supply, thereby effectively ensuring that the selected energy storage module is more reasonable, so as to achieve the purpose of preventing excessive use of energy storage modules in poor condition and making the consistency of energy storage modules in the energy storage system better.

[0092] In step S140, when the charge / discharge demand is a charging demand, step S140 may be to determine the required number of energy storage modules according to the discharge demand power in the discharge demand and the power of the energy storage modules, and when the required number of energy storage modules is greater than the number of energy storage modules, control all energy storage modules in the energy storage system to output power; when the required number of energy storage modules is less than the number of energy storage modules, select the required number of energy storage modules from multiple energy storage modules according to the comprehensive sorting order to control the output power of the selected energy storage modules.

[0093] Please combine Figure 5 Specifically, in this embodiment, step S140 includes:

[0094] Step S142a: Calculate the required amount of the energy storage module using a second preset calculation formula according to the discharge required power in the discharge requirement and the rated power of the energy storage module.

[0095] The second preset calculation formula is N=(Pload / Pe)+1, where N is the demand of the energy storage module, Pload is the discharge demand power, and Pe is the rated power of the energy storage module.

[0096] Step S144a: When the demand N of the energy storage module is less than the number M of energy storage modules in the energy storage system, N energy storage modules are selected in descending order of the comprehensive sorting order, so that the selected N energy storage modules output power, and the sum of the output powers of the N energy storage modules is the discharge demand power.

[0097] It should be noted that the comprehensive sorting order is the sorting order of the actual status of the energy storage modules, and the higher the sorting order, the better the performance of the corresponding energy storage module. Therefore, when N energy storage modules are selected for power supply in descending order according to the comprehensive sorting order, excessive use of energy storage modules in poor status can be avoided, thereby further improving the consistency of the energy storage modules in the energy storage system, thereby extending the service life of the energy storage modules, and preventing excessive use of energy storage modules in poor status, thereby frequently replacing energy storage modules and bringing unnecessary operation and maintenance costs, and avoiding the situation where the load requirements may not be met when using energy storage modules in poor status for power supply, thereby causing the energy storage system to stop operating.

[0098] In order to further improve the consistency of the energy storage modules in the energy storage system, in this embodiment, step S144a includes:

[0099] Step S1441a: Select N energy storage modules in descending order of the comprehensive ranking order, and sum the current SOCs of the selected N energy storage modules to obtain a total SOC.

[0100] Step S1442a: Calculate the calculated power corresponding to each of the N energy storage modules using a third preset calculation formula according to the current SOC of each of the N energy storage modules selected, the total SOC and the required discharge power, so that each of the N energy storage modules outputs the corresponding calculated power.

[0101] Wherein, the third preset calculation formula is: k输出 =(SOC k / SumS OC)*Pl 放电 , SumSOC=∑SOC k , k=1,2...N,SOC k is the current SOC of the kth energy storage module, P k输出 is the output power of the Kth energy storage module, Pload 充电 The power required for discharge.

[0102] It should be noted that, during the process of executing step S1442, when the power of an energy storage module among the selected N energy storage modules is exhausted, the process may return to executing step S110.

[0103] Through the above settings, the calculated power that should be output by each selected energy storage module is calculated according to the comprehensive ranking order of each energy storage module, the current SOC and the required discharge power, and the corresponding power is output according to the calculated power, so that the energy storage module with higher performance releases more electric energy, thereby further improving the consistency of the energy storage modules in the energy storage system, thereby further extending the service life of each energy storage module in the energy storage system.

[0104] Please refer to Figure 6 When the charging / discharging requirement is a charging requirement, the step S140 includes:

[0105] Step S142b: selecting the first J energy storage modules according to the order of the comprehensive ranking from low to high, and calculating the remaining power of each of the selected J energy storage modules.

[0106] The number of the selected energy storage modules should be less than or equal to the number of energy storage modules in the energy storage system. The specific number of the selected energy storage modules is not specifically limited here and can be set according to actual needs.

[0107] Step S144b: Calculate the charging calculation power of each of the selected J energy storage modules according to the charging demand power in the charging demand, the maximum storage capacity of each of the selected J energy storage modules, and the remaining capacity according to the fifth preset calculation formula, so that each of the J energy storage modules is charged according to the charging calculation power.

[0108] Wherein, the fifth preset calculation formula is: k输入 =((Q k电量 -Q k剩余 ) / SumQ)*Pload 充电 ,SumQ=∑(Q k电量 -Q k剩余 ), k=1,2...J,P k输入 Calculate the charging power of the Kth energy storage module, Q k电量 is the maximum storage capacity of the kth energy storage module, Q k剩余 is the remaining power of the Kth energy storage module, Pload 充电 Power is required for charging.

[0109] It should be noted that, during the charging process of the selected J energy storage modules, when the remaining power in the selected J energy storage modules reaches the maximum storage power, the process may return to step S110, or may return to step S110 when the remaining power in the selected J energy storage modules all reaches the maximum storage power. No specific limitation is made here, and the process may be set according to actual needs.

[0110] Through the above arrangement, the purpose of fast charging of energy storage modules with high power consumption can be achieved, so that energy storage modules with excessive power consumption in the energy storage system can quickly restore power, and further improve the consistency of charging of each energy storage module in the energy storage system, so that during the use of the energy storage system after charging is completed, since each energy storage module is comprehensively sorted at the full point, it reflects the more real state of the current energy storage module, and can select the optimal energy storage module for charging and discharging, prevent excessive use of energy storage modules in poor condition, try to make the consistency of energy storage modules in the energy storage system better, extend the service life of energy storage modules, prevent unnecessary operation and maintenance costs caused by premature replacement of energy storage modules, and prevent the shutdown of the energy storage system due to the use of energy storage modules in poor condition during operation, which cannot meet the load requirements.

[0111] Embodiment 2

[0112] This embodiment also provides a storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored. When the computer program is executed by a processor, the charge and discharge control method of the energy storage system in the first embodiment can be implemented.

[0113] The specific implementation process of the above method steps can be found in the first embodiment, and will not be repeated here.

[0114] Embodiment 3

[0115] An embodiment of the present application provides an energy storage system, which may include a controller and multiple energy storage modules. The energy storage system may also include a memory, wherein the controller is connected to each of the energy storage modules and the memory, respectively, and a computer program is stored in the memory. When the computer program is executed by the controller, the charge / discharge control method of the energy storage system in Example 1 is implemented.

[0116] In this embodiment, in order to facilitate the control of the charge / discharge power of each energy storage module, the energy storage module is connected to the controller via a bidirectional converter, and the structure of each energy storage module is exactly the same.

[0117] The controller is used to execute all or part of the steps in the charge / discharge control method of the energy storage system in Embodiment 1. The memory is used to store various types of data, which may include instructions of any application or method in the electronic device, and data related to the application.

[0118] The controller can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a microcontroller, a microprocessor or other electronic components, and is used to execute all or part of the steps in the method in the above embodiment 1.

[0119] The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0120] In summary, the present invention provides a charge / discharge control method, storage medium and energy storage system for an energy storage system, the method comprising: obtaining the charge / discharge demand and the current SOC and voltage difference of each of the energy storage modules, and sorting the current SOC of each of the energy storage modules to obtain the current SOC sorting order of each of the energy storage modules, obtaining the SOC correction difference of each of the energy storage modules according to the voltage difference and working state of each of the energy storage modules and the current SOC of each of the energy storage modules, obtaining the comprehensive sorting order of each of the energy storage modules according to the current SOC sorting order of each of the energy storage modules and the SOC correction difference of each of the energy storage modules, and controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand. It can effectively prevent the excessive use of energy storage modules in poor condition, try to make the consistency of energy storage modules in the energy storage system better, extend the service life of energy storage modules, prevent unnecessary operation and maintenance costs caused by premature replacement of energy storage modules, and prevent the shutdown of the energy storage system caused by the use of energy storage modules in poor condition during operation, and fail to meet load requirements.

[0121] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A charge / discharge control method for an energy storage system, characterized in that: The method comprises: Obtaining the charge / discharge demand and the current SOC and voltage difference of each energy storage module in the multiple energy storage modules included in the energy storage system, and sorting the current SOC of each of the energy storage modules to obtain the current SOC sorting order of each of the energy storage modules; Obtaining a SOC correction difference of each energy storage module according to the voltage difference and working state of each energy storage module and the current SOC of each energy storage module; Obtaining a comprehensive sorting order of each of the energy storage modules according to the current SOC sorting order of each of the energy storage modules and the SOC correction difference of each of the energy storage modules; Controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand; When the working state of the energy storage module is the discharge state, for each of the energy storage modules, according to the discharge lower limit voltage of the energy storage module, the current minimum voltage of the battery in the energy storage module and the voltage difference of the energy storage module, a first preset calculation formula is used to calculate to obtain the discharge SOC coefficient of each of the energy storage modules, wherein the first preset calculation formula is (V L -V LL ) / V D , V L is the current minimum voltage of the battery in the energy storage module, V LL is the lower discharge limit voltage of the energy storage module, V D is the voltage difference of the energy storage module; Obtaining the initial SOC under the discharge state corresponding to the discharge SOC coefficient of each of the energy storage modules; Taking the difference between the current SOC of each energy storage module and the initial SOC in the discharge state as the SOC correction difference of each energy storage module in the discharge state; When the working state of the energy storage module is the charging state, for each energy storage module, according to the charging upper limit voltage of the energy storage module, the current maximum voltage of the battery in the energy storage module and the voltage difference of the energy storage module, a fourth preset calculation formula is used to calculate to obtain the charging SOC coefficient of each energy storage module, wherein the fourth preset calculation formula is (V HL -V H ) / V D , V HL is the upper charging limit voltage of the energy storage module, V H is the current maximum voltage of the battery in the energy storage module, V D is the voltage difference of the energy storage module; Obtaining the initial SOC in the charging state corresponding to the charging SOC coefficient of each of the energy storage modules; The acquired difference between the initial SOC and the current SOC of each energy storage module in the charging state is used as the SOC correction difference of each energy storage module in the charging state.

2. The charge / discharge control method of the energy storage system according to claim 1, characterized in that: Controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand includes: The demand of the energy storage module is calculated using a second preset calculation formula according to the discharge demand power in the discharge demand and the rated power of the energy storage module, wherein the second preset calculation formula is N=(Pload / Pe)+1, N is the demand of the energy storage module, Pload is the discharge demand power, and Pe is the rated power of the energy storage module; When the demand N of the energy storage module is less than the number M of energy storage modules in the energy storage system, N energy storage modules are selected in descending order of the comprehensive sorting order so that the selected N energy storage modules output power, and the sum of the output powers of the N energy storage modules is the discharge demand power.

3. The charge / discharge control method of the energy storage system according to claim 2, characterized in that: Selecting N energy storage modules in descending order of the comprehensive ranking order so that the output power of the selected N energy storage modules is as follows: Selecting N energy storage modules in descending order of the comprehensive ranking order, and summing the current SOCs of the selected N energy storage modules to obtain a total SOC; According to the current SOC of each of the selected N energy storage modules, the total SOC and the required discharge power, a third preset calculation formula is used to calculate the calculated power corresponding to each of the N energy storage modules, so that each of the N energy storage modules outputs the corresponding calculated power, wherein the third preset calculation formula is: P k输出 =(SOC k / SumSOC)*Pload 放电 , SumSOC=∑SOC k , k=1,2...N,SOC k is the current SOC of the kth energy storage module, P k输出 is the output power of the Kth energy storage module, Pload 充电 The power required for discharge.

4. The charge / discharge control method of the energy storage system according to claim 1, characterized in that: Controlling the charge / discharge power of each of the energy storage modules according to the comprehensive sorting order and the charge / discharge demand includes: Selecting the first J energy storage modules according to the order of the comprehensive ranking from low to high, and calculating the remaining power of each of the selected J energy storage modules; According to the charging demand power in the charging demand, the maximum storage capacity and the remaining capacity of each of the selected J energy storage modules, the charging calculation power of each of the selected J energy storage modules is calculated according to the fifth preset calculation formula, so that each of the J energy storage modules is charged according to the charging calculation power, wherein the fifth preset calculation formula is: k输入 =((Q k电量 -Q k剩余 ) / SumQ)*Pload 充电 ,SumQ=∑(Q k电量 -Q k剩余 ), k=1,2...J,P k输入 Calculate the charging power of the Kth energy storage module, Q k电量 is the maximum storage capacity of the kth energy storage module, Q k剩余 is the remaining power of the Kth energy storage module, Pload 充电 Power is required for charging.

5. The charge / discharge control method of the energy storage system according to claim 1, characterized in that: The comprehensive sorting order of each energy storage module is obtained according to the current SOC sorting order of each energy storage module and the SOC correction difference of each energy storage module, including: Sorting the energy storage modules according to the SOC correction difference to obtain a corrected SOC sorting order of the energy storage modules; A weight calculation is performed according to the current SOC sorting order and the corrected SOC sorting order of each of the energy storage modules to obtain a comprehensive sorting order of each of the energy storage modules.

6. The charge / discharge control method of the energy storage system according to claim 1, characterized in that: The method further comprises: Acquire the historical charge / discharge efficiency of each of the energy storage modules, and sort the modules according to the historical charge / discharge efficiency to obtain a sorting order of the charging efficiency of each of the energy storage modules; Predicting according to the corrected SOC of each energy storage module and the current SOC of each energy storage module to obtain the predicted SOC of each energy storage module, and sorting the predicted SOC of each energy storage module to obtain the predicted SOC sorting order of each energy storage module; The comprehensive sorting order of each energy storage module is obtained according to the current SOC sorting order of each energy storage module and the SOC correction difference of each energy storage module, including: Sorting the energy storage modules according to the SOC correction difference to obtain a corrected SOC sorting order of the energy storage modules; A weight calculation is performed according to the current SOC sorting order, the corrected SOC sorting order, the charging efficiency sorting order and the predicted SOC sorting order of each of the energy storage modules to obtain a comprehensive sorting order of each of the energy storage modules.

7. A storage medium storing a computer program, characterized in that: When the computer program is executed by one or more processors, the method according to any one of claims 1 to 6 is implemented.

8. An energy storage system, characterized in that: It comprises a plurality of energy storage modules and a controller connected in parallel, wherein the controller is respectively connected to each of the energy storage modules, and the controller is used to execute the charge / discharge control method of the energy storage system according to any one of claims 1 to 6.

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