Battery evaluation method and device, computer equipment, storage medium and computer program product

Abstract

The invention relates to a battery evaluation method and device, computer equipment, a storage medium and a computer program product. The method comprises the following steps: obtaining a first curve of a battery according to the voltage and the charge state of the battery; the first curve is used for representing the change relation between the voltage and the state of charge; obtaining a second curve of the battery according to the first curve and the charge state; the second curve is used for representing the intensity of the voltage changing along with the charge state; performing region division processing on the first curve based on the second curve to obtain a plurality of regions in the first curve; obtaining a target evaluation model of the battery according to the plurality of areas; the evaluation model is used for carrying out consistency evaluation processing on the battery. By adopting the method, the accuracy of battery consistency evaluation can be improved.

Description

Technical Field

[0001] The present application relates to the field of electrochemical energy storage technology, and in particular to a battery evaluation method, device, computer equipment, storage medium and computer program product. Background Art

[0002] In recent years, the world's energy and environmental problems have become increasingly apparent, and new energy technologies need to be vigorously developed. Energy storage is an important part of new energy technologies, and electrochemical energy storage is one of the most important energy storage methods. Batteries are significantly superior to other batteries in terms of energy, power, cycle life, etc., and are an important carrier of electrochemical energy storage. Energy storage battery systems often integrate a large number of battery cells, and the consistency of battery cells is the key to ensuring the normal use of energy storage battery systems.

[0003] At present, battery inconsistency evaluation is mostly judged by a fixed difference threshold. However, the power parameters of the battery change dynamically during the charging and discharging process, and the accuracy of consistency judgment using a fixed difference threshold is low. Summary of the invention

[0004] Based on this, it is necessary to provide a battery evaluation method, device, computer equipment, computer-readable storage medium and computer program product that can evaluate the accuracy of battery consistency in response to the above technical problems.

[0005] In a first aspect, the present application provides a battery evaluation method. The method comprises:

[0006] Obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge;

[0007] Obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge;

[0008] Based on the second curve, performing region division processing on the first curve to obtain a plurality of regions in the first curve;

[0009] A target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0010] In one embodiment, obtaining a target evaluation model of the battery according to the multiple regions includes:

[0011] Based on the state of charge, constructing initial evaluation models of the multiple regions;

[0012] According to the first curve, the initial evaluation model is subjected to voltage conversion processing to obtain a target evaluation model of the battery.

[0013] In one embodiment, constructing initial evaluation models of the multiple regions based on the state of charge includes:

[0014] Obtaining an evaluation threshold of the state of charge;

[0015] Based on the evaluation threshold, construct an evaluation threshold matrix for the multiple regions;

[0016] According to the evaluation threshold matrix, initial evaluation models of the multiple regions are obtained.

[0017] In one embodiment, obtaining a second curve of the battery according to the first curve and the state of charge includes:

[0018] According to the first curve, obtaining a change in the state of charge and a change in the voltage;

[0019] According to the rate of change of the state of charge and the amount of change of the voltage, a change degree value is obtained; the change degree value is used to characterize the severity of the change of the voltage with the state of charge;

[0020] Based on the variation degree value and the state of charge, a second curve of the battery is constructed.

[0021] In one embodiment, before obtaining the first curve of the battery according to the voltage and the state of charge of the battery, the method further includes:

[0022] Charging or discharging the battery to obtain the voltage of the battery;

[0023] The state of charge of the battery is obtained according to the battery capacity, battery efficiency and current of the battery.

[0024] In one embodiment, after obtaining the target evaluation model of the battery according to the multiple regions, the method further includes:

[0025] Obtaining current voltage difference information of the battery;

[0026] The voltage difference information is subjected to consistency evaluation processing by using the target evaluation model to obtain a consistency evaluation result of the battery.

[0027] In a second aspect, the present application also provides a battery evaluation device. The device comprises:

[0028] A first curve building module, used to obtain a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the change relationship between the voltage and the state of charge;

[0029] A second curve building module, used for obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used for representing the severity of the change of the voltage with the state of charge;

[0030] A curve region division module, configured to perform region division processing on the first curve based on the second curve to obtain a plurality of regions in the first curve;

[0031] An evaluation model acquisition module is used to obtain a target evaluation model of the battery according to the multiple areas; the evaluation model is used to perform consistency evaluation processing on the battery.

[0032] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0033] Obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge;

[0034] Obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge;

[0035] Based on the second curve, performing region division processing on the first curve to obtain a plurality of regions in the first curve;

[0036] A target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0037] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0038] Obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge;

[0039] Obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge;

[0040] Based on the second curve, performing region division processing on the first curve to obtain a plurality of regions in the first curve;

[0041] A target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0042] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0043] Obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge;

[0044] Obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge;

[0045] Based on the second curve, performing region division processing on the first curve to obtain a plurality of regions in the first curve;

[0046] A target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0047] The above-mentioned battery evaluation method, device, computer equipment, storage medium and computer program product obtain the first curve of the battery according to the voltage and state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge; the second curve of the battery is obtained according to the first curve and the state of charge; the second curve is used to characterize the severity of the voltage change with the state of charge; based on the second curve, the first curve is divided into regions to obtain multiple regions in the first curve; based on the multiple regions, the target evaluation model of the battery is obtained; the evaluation model is used to perform consistency evaluation on the battery. Using this method, a first curve that characterizes the changing relationship between the voltage and the state of charge is first established, and then the first curve is used to construct a second curve that reflects the severity of the change, so that the first curve is further subdivided into multiple regions based on the second curve, and the battery is evaluated for consistency through the evaluation model, which greatly improves the accuracy of the battery consistency evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A diagram showing an application environment of a battery evaluation method in one embodiment;

[0049] Figure 2 is a schematic flow chart of a battery evaluation method in one embodiment;

[0050] Figure 3 A schematic flow chart of steps for obtaining a target evaluation model of a battery according to multiple regions in one embodiment;

[0051] Figure 4 is a flow chart of a battery evaluation method in another embodiment;

[0052] Figure 5 is a flow chart of a battery evaluation method in yet another embodiment;

[0053] Figure 6 is a schematic diagram of an OCV-SOC curve in one embodiment;

[0054] Figure 7 A schematic diagram of a voltage slope changing with SOC in an embodiment and a partially enlarged schematic diagram thereof;

[0055] Figure 8 It is a schematic diagram of the division of seven areas of three categories, namely, a platform area, a gentle slope area, and a steep slope area, of an OVC-SOC curve in one embodiment;

[0056] Fig. 9 A schematic diagram of a consistency evaluation threshold map based on voltage difference in one embodiment;

[0057] Fig.10 is a structural block diagram of a battery evaluation device in one embodiment;

[0058] Fig.11 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0060] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0061] The battery evaluation method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the battery 101 communicates with the energy storage system 102 through the network. The data storage system can store the data that the energy storage system 102 needs to process. The data storage system can be integrated on the server, or it can be placed on the cloud or other network servers. Among them, the battery 101 can be installed in the power equipment, or it can be independently set in the scene. It can be but not limited to various instruments and equipment in the field of electricity; the battery 101 can be but not limited to various lithium iron phosphate batteries. The energy storage system 102 can be a battery energy storage system of an energy storage power station. The energy storage system can be installed on an independent server or a server cluster composed of multiple servers, or it can be installed on a terminal. Among them, the terminal can be but not limited to various computer devices, laptops, smart phones, tablets, Internet of Things devices, etc.

[0062] In one embodiment, Figure 2 As shown, a battery evaluation method is provided, which is applied to Figure 1 The energy storage system in FIG. 1 is taken as an example to illustrate the method, which includes the following steps:

[0063] Step S201, obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge.

[0064] Among them, the battery refers to the device that stores and releases electrical energy in the energy storage power station scenario. In practical applications, the battery can be an electrochemical cell, which converts chemical energy into electrical energy through a chemical reaction. During the discharge process, electrons flow from the anode to the cathode, generating current.

[0065] The voltage may be the open circuit voltage of the battery. The open circuit voltage (OCV) is used to characterize the external output characteristics of the battery without external excitation, and can accurately characterize the battery's state of charge, aging state, safety state, etc. The open circuit voltage can be obtained through low-power constant power or low-current constant current charging / discharging.

[0066] Among them, the state of charge (SOC) is used to indicate the relative amount of charge currently stored in a battery or energy storage system. The state of charge is usually expressed in percentages, such as 50%, 70%, and 100%. It should be noted that the state of charge is a state quantity, and the state of charge cannot be obtained through measurement. Only an estimate of the state of charge can be obtained, which itself contains estimation errors and is difficult to reflect the true consistency state. Therefore, this application calculates the state of charge through power parameters to improve the accuracy of the calculated state of charge.

[0067] Specifically, the energy storage system uses the charge and discharge operating parameters to perform charge and discharge tests on the battery to obtain the voltage, current, battery capacity and other power parameters of the battery during the charge and discharge process (i.e., the charging and discharging process). The battery state of charge is then calculated using the acquired parameters. The energy storage system then constructs a state of charge-voltage model based on voltage and state of charge, and calculates the change relationship between voltage and state of charge through the state of charge-voltage model, and then draws the first curve of the battery based on the calculated change relationship.

[0068] In practical applications, the state of charge-voltage model can be expressed by the following formula:

[0069] U = f (SOC)

[0070] Where U represents voltage and SOC represents state of charge.

[0071] Based on the above state of charge-voltage model, the energy storage system can use the state of charge as the horizontal axis and the voltage as the vertical axis to draw a voltage-SOC curve from 100% to 1% SOC at 1% SOC intervals, and finally obtain the first curve of the battery.

[0072] Step S202, obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge.

[0073] Specifically, the energy storage system can first calculate the slope of the first curve (or the absolute value of the slope), and then the energy storage system obtains the slope of the curve. The energy storage system draws a second curve of the battery based on the slope of the curve and the state of charge. For example, the state of charge can be used as the horizontal coordinate and the slope of the curve can be used as the vertical coordinate to draw the curve, and then the energy storage system obtains the second curve of the battery. It can be understood that since the slope of the first curve is introduced into the second curve, the second curve can better characterize the degree to which the battery voltage changes with the state of charge.

[0074] Step S203: based on the second curve, perform region division processing on the first curve to obtain a plurality of regions in the first curve.

[0075] The region refers to the region where the first curve is separated by a straight line perpendicular to the x-axis.

[0076] Specifically, the energy storage system can determine the secondary boundary conditions for the consistency evaluation of the battery based on the second curve, and set multiple judgment thresholds for the secondary boundary conditions. For example, multiple judgment thresholds for voltage can be set, and straight lines perpendicular to the x-axis can be set for the multiple judgment thresholds for voltage, thereby dividing the first curve into multiple categories. Each category can also be further subdivided into multiple regions to facilitate the subsequent construction of a target evaluation model for the battery.

[0077] For example, the judgment threshold of the secondary boundary condition may include a first judgment threshold ΔdU 1 , the second judgment threshold ΔdU 2 (ΔdU 1 <ΔdU 2 ). The energy storage system passes the first judgment threshold ΔdU 1 and the second judgment threshold ΔdU 2 The voltage curve is divided into three categories, namely, a platform area, a gentle slope area and a steep slope area, and each category may include M areas.

[0078] Step S204, obtaining a target evaluation model of the battery according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0079] The target evaluation model refers to a model used to determine whether the battery meets the consistency. The target evaluation model can be a model constructed in a mathematical form, such as a matrix, formula, or other mathematical form. Of course, it can also be a model constructed by a machine learning algorithm, such as a classification algorithm in machine learning such as a random forest.

[0080] Specifically, the energy storage system can establish a sub-evaluation model for each area, and then combine all the sub-evaluation models to construct a target evaluation model for the battery. Furthermore, when the energy storage system subsequently collects the current power parameters such as the battery voltage, it can input them into the target evaluation model to determine whether the battery currently meets the consistency through the target evaluation model.

[0081] It should be noted that the inconsistency of the battery includes initial inconsistency and inconsistency during use. Initial inconsistency includes inconsistent initial capacity and internal resistance, and inconsistency during use includes inconsistent temperature environment, inconsistent charge and discharge current rates, and inconsistent aging attenuation under the influence of initial inconsistency. As for the battery voltage, especially for lithium iron phosphate batteries, its voltage window is relatively narrow. The voltage change from 0% SOC to 100% SOC is 1150mV, but due to the platform characteristics of its voltage curve, the voltage change from 10% SOC to 98% SOC is only 144mV. Therefore, in traditional technology, only relying on a fixed voltage difference threshold as a battery consistency judgment condition cannot accurately judge the consistency state of the battery energy storage system within the full SOC range of the battery.

[0082] In the above-mentioned battery evaluation method, a first curve of the battery is obtained according to the voltage and state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge; a second curve of the battery is obtained according to the first curve and the state of charge; the second curve is used to characterize the severity of the voltage change with the state of charge; based on the second curve, the first curve is divided into regions to obtain multiple regions in the first curve; based on the multiple regions, a target evaluation model of the battery is obtained; the evaluation model is used to perform consistency evaluation on the battery. Using this method, a first curve characterizing the changing relationship between the voltage and the state of charge is first established, and then the first curve is used to construct a second curve reflecting the severity of the change, so that the first curve is further subdivided into multiple regions based on the second curve, and the battery is evaluated for consistency through the evaluation model, which greatly improves the accuracy of the battery consistency evaluation.

[0083] In one embodiment, Figure 3 As shown, in the above step S204, a target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery, and specifically includes the following contents:

[0084] Step S301: constructing initial evaluation models for multiple regions based on the state of charge.

[0085] The initial evaluation model refers to an evaluation model constructed based on the state of charge.

[0086] Specifically, the energy storage system can use the state of charge as a consistency evaluation standard to determine the evaluation threshold of each area in the first curve, and then use the evaluation thresholds of all areas to construct an initial evaluation model for the battery.

[0087] Step S302: performing voltage conversion processing on the initial evaluation model according to the first curve to obtain a target evaluation model of the battery.

[0088] Specifically, the energy storage system can pre-construct a voltage conversion model; then use the voltage conversion model to convert the initial evaluation model based on the state of charge into a target evaluation model based on voltage, that is, input the initial evaluation threshold in the initial evaluation model into the voltage conversion model, thereby calculating the target evaluation threshold at the same position as the initial evaluation threshold, and construct a target evaluation threshold matrix using the target evaluation threshold, and set the target evaluation threshold matrix as the target evaluation model of the battery.

[0089] In practical applications, the voltage conversion model can be expressed by the following formula:

[0090] ΔU MN = f(SOC) - f(SOC-ΔSOC MN )

[0091] The target evaluation model based on voltage can be represented by the evaluation threshold matrix as shown below:

[0092]

[0093] In the formula, ΔU MN It represents the target evaluation threshold value based on voltage U in the Mth area and the Nth level consistency judgment standard.

[0094] In this embodiment, an initial evaluation model based on the battery state of charge is first constructed, and then the initial evaluation model is converted into a target evaluation model based on the battery voltage, so that the subsequent steps can make consistency judgments based on the battery voltage through the target evaluation model, which helps to enhance the accuracy of the energy storage system's judgment of battery consistency in different states.

[0095] In one embodiment, the above step S301 constructs initial evaluation models for multiple regions based on the state of charge, specifically including the following contents: obtaining an evaluation threshold of the state of charge; constructing an evaluation threshold matrix for multiple regions based on the evaluation threshold; and obtaining initial evaluation models for multiple regions based on the evaluation threshold matrix.

[0096] The evaluation threshold refers to the threshold used to determine whether the battery meets the consistency.

[0097] Specifically, the energy storage system determines the initial evaluation thresholds of the battery consistency judgment standards in M ​​areas and N levels of the first curve based on the state of charge, and constructs the initial evaluation thresholds of the battery consistency judgment standards in these M areas and N levels into an initial evaluation threshold matrix; the energy storage system can set the initial evaluation threshold matrix as an initial evaluation model.

[0098] In practical applications, the initial evaluation model of M regions and N levels based on the state of charge can be represented by the initial evaluation threshold matrix as shown below:

[0099]

[0100] In the formula, ΔSOC MN It represents the evaluation threshold value based on the state of charge SOC in the Mth area and the Nth level consistency judgment standard.

[0101] In this embodiment, an evaluation threshold matrix for each area in the first curve is constructed using the evaluation threshold of the state of charge; the evaluation threshold matrix is ​​then set as the initial evaluation model of the battery, thereby realizing the construction of an evaluation model based on the state of charge, laying the foundation for subsequent evaluation model conversion processing.

[0102] In one embodiment, the above step S202 obtains a second curve of the battery according to the first curve and the state of charge, and specifically includes the following contents: according to the first curve, obtain the change of the state of charge and the change of the voltage; according to the change rate of the state of charge and the change of the voltage, obtain the degree of change value; the degree of change value is used to characterize the degree of change of the voltage with the state of charge; based on the degree of change value and the state of charge, construct the second curve of the battery.

[0103] The change refers to a numerical value that describes the increase or decrease of an electric power parameter (such as state of charge or voltage) within a certain period of time.

[0104] Specifically, the energy storage system can calculate the change in the state of charge in the first curve, and the change in the voltage corresponding to the state of charge (which can be the open circuit voltage); and then use the change in the state of charge and the change in the voltage corresponding to the state of charge (which can be the open circuit voltage) to calculate the slope of the first curve, so as to characterize the degree of change through the slope of the curve. Then, the energy storage system uses the slope of the curve as the ordinate and the state of charge as the abscissa to draw the second curve of the battery.

[0105] In practical applications, the curve slope OCV' can be calculated by the following formula:

[0106]

[0107] Where ΔSOC represents the change in state of charge, and ΔU represents the change in open circuit voltage corresponding to ΔSOC.

[0108] In this embodiment, the slope of the first curve is calculated using the change in the state of charge and the change in the voltage of the first curve. Then, based on the slope of the curve and the state of charge, a second curve of the battery is constructed, so that the second curve provides reliable data support for the regional division of the first curve, which helps to improve the division accuracy of the first curve, thereby improving the accuracy of the battery consistency evaluation.

[0109] In one embodiment, before obtaining the first curve of the battery according to the voltage and state of charge of the battery in the above step S201, it also includes: charging or discharging the battery to obtain the voltage of the battery; and obtaining the state of charge of the battery according to the battery capacity, battery efficiency and current of the battery.

[0110] Among them, battery capacity refers to the battery's ability to store and release electrical energy.

[0111] Among them, battery efficiency refers to the effectiveness of energy conversion during the battery's charge and discharge process. Battery efficiency is usually expressed as a percentage. Battery efficiency is used to reflect the energy loss of the battery during use. The higher the battery efficiency, the less energy loss during the charge and discharge process, and the battery can better utilize the stored energy.

[0112] Specifically, the energy storage system can use electrical equipment such as a discharge tester and an environmental temperature chamber to perform a charging test or a discharging test on the battery using a small current. The energy storage system can also use an SOC interval charging and discharging test, and then the energy storage system obtains the battery's voltage, current, battery capacity and other electrical parameters during the charging test or the discharging test. The energy storage system can then use the initial state of charge of the charging test or the discharging test, as well as the battery capacity, battery efficiency and current of the battery, to calculate the battery's state of charge. In actual applications, the energy storage system can use the ampere-hour integration method to calculate the battery's state of charge during the charging test or the discharging test. The state of charge calculation process can be expressed by the following formula:

[0113]

[0114] In the formula, SOC 0 represents the initial state of charge, Q max represents the battery capacity, η represents the battery efficiency, i batt Indicates the battery current.

[0115] In this embodiment, by charging or discharging the battery, the power parameters such as the voltage of the battery during the charge and discharge test can be obtained; then, the battery capacity, battery efficiency and current of the battery can be used to accurately calculate the battery state of charge, providing reliable data support for subsequent curve drawing.

[0116] In one embodiment, after obtaining the target evaluation model of the battery according to multiple regions in the above step S204, the method further includes: obtaining the current voltage difference information of the battery; and performing consistency evaluation processing on the voltage difference information through the target evaluation model to obtain a consistency evaluation result of the battery.

[0117] The battery difference information may be a voltage range difference. The voltage range difference refers to the difference between the maximum and minimum voltages in a circuit, that is, the voltage range difference = Vmax − Vmin; wherein Vmax is the highest voltage value collected in the circuit, and Vmin is the lowest voltage value collected in the circuit.

[0118] Specifically, the energy storage system can collect power data such as the current voltage of the battery, the charge state position of the battery, etc. in real time, and then calculate the difference information of the power data based on the maximum voltage and the minimum voltage, so that the energy storage system obtains the voltage difference information of the battery. The energy storage system determines the target evaluation threshold corresponding to the charge state position in the target evaluation model based on the charge state position. By comparing the size relationship between the target evaluation threshold and the voltage difference information, the consistency evaluation result of the battery can be obtained.

[0119] In this embodiment, the battery consistency evaluation result is obtained by comparing the current voltage difference information of the battery with the target evaluation threshold corresponding to the current charge state position of the battery in the target evaluation model. The battery consistency evaluation can be precisely refined to the category and level, effectively improving the accuracy of the battery consistency evaluation.

[0120] In one embodiment, Figure 4 As shown, another battery evaluation method is provided, which can be applied to Figure 1 The energy storage system in FIG. 1 is taken as an example to illustrate the method, which includes the following steps:

[0121] Step S401, charging or discharging the battery to obtain the battery voltage.

[0122] Step S402, obtaining the state of charge of the battery according to the battery capacity, battery efficiency and current of the battery.

[0123] Step S403, obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge.

[0124] Step S404: obtaining a change in the state of charge and a change in the voltage according to the first curve.

[0125] Step S405, obtaining a change degree value according to the change rate of the state of charge and the change amount of the voltage; the change degree value is used to characterize the severity of the change of the voltage with the state of charge.

[0126] Step S406: construct a second curve of the battery based on the change degree value and the state of charge.

[0127] Step S407: Based on the second curve, the first curve is divided into regions to obtain a plurality of regions in the first curve.

[0128] Step S408: constructing initial evaluation models for multiple regions based on the state of charge.

[0129] Step S409: performing voltage conversion processing on the initial evaluation model according to the first curve to obtain a target evaluation model of the battery.

[0130] Step S410, obtaining the current voltage difference information of the battery; performing consistency evaluation processing on the voltage difference information through the target evaluation model to obtain the consistency evaluation result of the battery.

[0131] The above-mentioned battery evaluation method can achieve the following beneficial effects: firstly, a first curve characterizing the changing relationship between voltage and state of charge is established, and then a second curve reflecting the drastic degree of the change is constructed using the first curve, and the first curve is further subdivided into multiple regions based on the second curve, and the battery is evaluated for consistency through the evaluation model, which greatly improves the accuracy of battery consistency evaluation.

[0132] In order to more clearly illustrate the battery evaluation method provided by the embodiment of the present disclosure, the above-mentioned battery evaluation method is specifically described below with a specific embodiment. Figure 5 As shown, another battery evaluation method is provided, which can be applied to Figure 1 The energy storage system in the system includes the following contents:

[0133] Step S501, carry out constant current / constant power charge / discharge test of battery cells of energy storage system according to common operating parameters of energy storage power station: use charge / discharge tester, environmental temperature box, etc. to carry out constant current or constant power charge / discharge test, and obtain voltage-SOC curve; the voltage curve can be obtained through constant current or constant power charge / discharge test, or through constant current or constant power charge / discharge test with equal SOC interval. Constant power discharge test method is adopted here.

[0134] Step S502, using the ampere-hour integration method to obtain the SOC of the lithium iron phosphate battery during the test, thereby constructing a voltage-SOC curve. Figure 6 Schematic diagram of the OCV-SOC curve.

[0135] Step S503, constructing a voltage slope-SOC curve of the battery, dividing the voltage-SOC curve into a platform area, a gentle slope area and a steep slope area: Figure 7 The schematic diagram of the voltage slope changing with SOC and its partial enlarged schematic diagram are shown in Figure 1. The voltage slope-SOC curve from 100% to 1% SOC is obtained at 1% SOC intervals. The ΔdU1 and ΔdU2 secondary thresholds are set to divide the OVC-SOC curve into seven intervals, namely, platform area, gentle slope area, and steep slope area. Figure 8 This is a schematic diagram of the division of the OVC-SOC curve into seven areas: platform area, gentle slope area, and steep slope area.

[0136] Step S504, formulate a multi-level consistency evaluation threshold matrix based on SOC: based on SOC, set three consistency evaluation thresholds of 5% SOC, 10% SOC, and 20% SOC. For the sake of simplicity, the consistency evaluation thresholds of all SOC intervals are the same, and obtain the consistency evaluation threshold matrix based on SOC:

[0137]

[0138] Step S505, formulate a multi-level consistency evaluation threshold matrix based on voltage: using the voltage-SOC curve, further convert the consistency evaluation threshold matrix based on SOC into a consistency evaluation threshold matrix based on voltage:

[0139]

[0140] Step S506, using the existing multi-level consistency evaluation threshold matrix, the actual voltage range of the battery is judged to be consistent: Fig. 9 It is a schematic diagram of the consistency evaluation threshold map based on voltage difference. It is also possible to obtain the actual operation data of the battery monitored by the energy storage system, and conduct consistency evaluation on the battery by combining the voltage extreme difference, SOC, and the voltage-based consistency evaluation threshold matrix during the actual operation.

[0141] In this embodiment, the effects of battery voltage and SOC on consistency are comprehensively considered, and the refined battery consistency evaluation over the entire SOC range of the battery can be adapted, thereby effectively improving the accuracy of the consistency evaluation.

[0142] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0143] Based on the same inventive concept, the embodiment of the present application also provides a battery evaluation device for implementing the battery evaluation method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more battery evaluation device embodiments provided below can refer to the limitations of the battery evaluation method above, and will not be repeated here.

[0144] In one embodiment, Fig.10 As shown, a battery evaluation device 1000 is provided, comprising: a first curve construction module 1001, a second curve construction module 1002, a curve region division module 1003 and an evaluation model acquisition module 1004, wherein:

[0145] The first curve building module 1001 is used to obtain a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge.

[0146] The second curve building module 1002 is used to obtain a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the voltage change with the state of charge.

[0147] The curve region division module 1003 is used to perform region division processing on the first curve based on the second curve to obtain multiple regions in the first curve.

[0148] The evaluation model acquisition module 1004 is used to obtain a target evaluation model of the battery according to multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

[0149] In one embodiment, the consistency evaluation module 1004 is further used to construct initial evaluation models of multiple regions based on the state of charge; and perform voltage conversion processing on the initial evaluation model according to the first curve to obtain a target evaluation model of the battery.

[0150] In one embodiment, the battery evaluation device 1000 further includes an initial model construction module for obtaining an evaluation threshold of the state of charge; constructing an evaluation threshold matrix of multiple regions based on the evaluation threshold; and obtaining initial evaluation models of multiple regions according to the evaluation threshold matrix.

[0151] In one embodiment, the second curve construction module 1002 is also used to obtain the change in the state of charge and the change in the voltage based on the first curve; obtain the degree of change value based on the rate of change of the state of charge and the change in the voltage; the degree of change value is used to characterize the degree of change of the voltage with the state of charge; based on the degree of change value and the state of charge, construct the second curve of the battery.

[0152] In one embodiment, the battery evaluation device 1000 further includes a state of charge acquisition module, which is used to charge or discharge the battery to obtain the battery voltage; and obtain the battery state of charge according to the battery capacity, battery efficiency and current of the battery.

[0153] In one embodiment, the battery evaluation device 1000 further includes a consistency evaluation module for obtaining current voltage difference information of the battery; and performing consistency evaluation processing on the voltage difference information through a target evaluation model to obtain a consistency evaluation result of the battery.

[0154] Each module in the above-mentioned battery evaluation device can be implemented in whole or in part by software, hardware or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0155] In one embodiment, a computer device is provided. The computer device may be a terminal. The terminal is equipped with an energy storage system. The internal structure diagram thereof may be as follows: Fig.11 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a battery evaluation method is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0156] Those skilled in the art will understand that Fig.11The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0157] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0158] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0159] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0160] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0161] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A battery evaluation method, characterized in that: The method comprises: Obtaining a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the changing relationship between the voltage and the state of charge; Obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used to characterize the severity of the change of the voltage with the state of charge; Based on the second curve, performing region division processing on the first curve to obtain a plurality of regions in the first curve; A target evaluation model of the battery is obtained according to the multiple regions; the evaluation model is used to perform consistency evaluation processing on the battery.

2. The method according to claim 1, characterized in that The step of obtaining a target evaluation model of the battery according to the plurality of regions includes: Based on the state of charge, constructing initial evaluation models of the multiple regions; According to the first curve, the initial evaluation model is subjected to voltage conversion processing to obtain a target evaluation model of the battery.

3. The method according to claim 2, characterized in that The constructing the initial evaluation models of the multiple regions based on the state of charge includes: Obtaining an evaluation threshold of the state of charge; Based on the evaluation threshold, construct an evaluation threshold matrix for the multiple regions; According to the evaluation threshold matrix, initial evaluation models of the multiple regions are obtained.

4. The method according to claim 1, characterized in that The step of obtaining a second curve of the battery according to the first curve and the state of charge includes: According to the first curve, obtaining a change in the state of charge and a change in the voltage; According to the rate of change of the state of charge and the amount of change of the voltage, a change degree value is obtained; the change degree value is used to characterize the severity of the change of the voltage with the state of charge; Based on the variation degree value and the state of charge, a second curve of the battery is constructed.

5. The method according to claim 1, characterized in that Before obtaining a first curve of the battery according to the voltage and the state of charge of the battery, the method further includes: Charging or discharging the battery to obtain the voltage of the battery; The state of charge of the battery is obtained according to the battery capacity, battery efficiency and current of the battery.

6. The method according to any one of claims 1 to 5, characterized in that: After obtaining the target evaluation model of the battery according to the multiple regions, the method further includes: Obtaining current voltage difference information of the battery; The voltage difference information is subjected to consistency evaluation processing by using the target evaluation model to obtain a consistency evaluation result of the battery.

7. A battery evaluation device, characterized in that: The device comprises: A first curve building module, used to obtain a first curve of the battery according to the voltage and the state of charge of the battery; the first curve is used to characterize the change relationship between the voltage and the state of charge; A second curve building module, used for obtaining a second curve of the battery according to the first curve and the state of charge; the second curve is used for representing the severity of the change of the voltage with the state of charge; A curve region division module, configured to perform region division processing on the first curve based on the second curve to obtain a plurality of regions in the first curve; An evaluation model acquisition module is used to obtain a target evaluation model of the battery according to the multiple areas; the evaluation model is used to perform consistency evaluation processing on the battery.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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