Battery health state estimation model construction method, state estimation method and device

Abstract

The invention relates to the technical field of batteries, and discloses a battery health state estimation model construction method, a battery health state estimation method and a battery health state estimation device, and the model construction method comprises the following steps: according to the corresponding relationship among the current full capacity, the charge-discharge rate, the service time and the temperature of a fresh-state battery, and the corresponding relationship among the average voltage, the temperature and the service time, calculating the state of the fresh-state battery; according to the method, the battery health estimation model is established according to the rated energy and the corresponding relation between the rated energy and the temperature, the model established through the method has high battery health state estimation precision, the model establishment efficiency is high, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery health state estimation model construction method, a state estimation method and a device. Background Art

[0002] To address the severe challenges posed by emerging energy sources such as wind and solar power to the stable operation of power systems, energy storage systems, with batteries as their core components, play a vital role in power systems. Accurate and rapid estimation of the state of health (SOH) of energy storage batteries is crucial for the management, control, safe, and efficient operation of energy storage systems.

[0003] SOH refers to the percentage of the battery's current charge to the total available charge. There are currently three ways to measure the battery's SOH: (1) Use the ratio of the current battery's full charge capacity to the rated capacity to measure the battery's health status. Capacity is the integral of current relative to time. Since energy storage batteries do not use a constant current charge and discharge operation strategy (but a constant power charge and discharge strategy) during actual operation, using the battery capacity ratio to estimate the energy storage battery's SOH is different from the actual charge and discharge method during operation, resulting in estimation errors; (2) Use the change in the battery's internal resistance to measure the battery's health status. Since, during battery use, various electrical characteristics other than internal resistance change, using the change in the battery's internal resistance to measure the battery's SOH will also produce a large estimation error; (3) Use the ratio of the current battery's full charge energy to the fresh battery's rated energy to measure the battery's health status. Energy is the integral of power relative to time. Since energy storage batteries use a constant power charge and discharge operation strategy during actual operation, using the battery energy ratio to estimate the energy storage battery's SOH is the same as the actual charge and discharge method during operation, and the estimation error for energy storage batteries is small.

[0004] Currently, SOH estimation methods mainly include battery modeling and data-driven methods. When using the battery model method to estimate SOH, multiple factors such as temperature, aging, and charge / discharge rate are coupled and influenced by each other. Therefore, modeling the coupled factors is the key to using this method for SOH estimation. Data-driven methods are the mainstream of SOH estimation, but machine learning and deep learning have high requirements for the quality and quantity of training datasets and are highly data-dependent. When training data is imbalanced, the interpretation of prediction results is low. Summary of the Invention

[0005] In view of this, the present invention provides a battery health status estimation model construction method, a state estimation method and an apparatus to solve the problem of being unable to quickly and accurately estimate the battery health status.

[0006] In the first aspect, the present invention provides a method for constructing a battery health status estimation model, including: performing constant power charge and discharge tests, constant current charge and discharge tests, and DC internal resistance tests on a fresh battery at different temperature points within a preset temperature range, and obtaining a first functional relationship, a second functional relationship, and a third functional relationship, respectively. The first functional relationship, the second functional relationship, and the third functional relationship are respectively used to characterize the correspondence between the rated energy, mean voltage, DC internal resistance, and temperature of the fresh battery; performing an aging test on the fresh battery at a standard temperature, and obtaining a fourth functional relationship and a fifth functional relationship, respectively. The fourth functional relationship is used to characterize the correspondence between the current full charge capacity, charge and discharge rate, and usage time of the fresh battery at different times. The fifth functional relationship is used to characterize the corresponding relationship between the mean voltage and the usage time; the second functional relationship is combined with the fifth functional relationship to obtain the sixth functional relationship, which is used to characterize the corresponding relationship between the mean voltage, temperature, and usage time of the fresh battery; the fourth functional relationship is corrected by the third functional relationship to obtain the seventh functional relationship, which is used to characterize the corresponding relationship between the current full-charge capacity, charge and discharge rate, usage time, and temperature; a battery health estimation model is established based on the seventh functional relationship, the sixth functional relationship, and the first functional relationship. The battery health estimation model is used to estimate the health status of the battery to be tested based on the usage time, charge and discharge rate, and ambient temperature of the battery to be tested.

[0007] The method for constructing a battery health state estimation model provided by an embodiment of the present invention establishes a battery health estimation model based on the seventh functional relationship, the sixth functional relationship, and the first functional relationship, wherein the seventh functional relationship represents the corresponding relationship between the current full-charge capacity, the charge and discharge rate, the usage time, and the temperature, the sixth functional relationship represents the relationship between the mean voltage and the temperature and the usage time, and the first functional relationship represents the relationship between the rated energy and the temperature. It can be seen that the model established by the embodiment of the present invention fully considers the changes in battery parameters caused by battery aging, temperature changes, and charge and discharge rate changes during use, realizes multi-factor coupling modeling, and thus improves the estimation accuracy of the battery health state estimation model. In addition, the embodiment of the present invention constructs a health state estimation model based on experimental data, without the need for complex training processes such as machine learning, thereby improving the estimation efficiency of the battery health state and reducing the cost of building the model. Furthermore, in this application, in order to determine the coupling relationship between the current full-charge capacity and the charge and discharge rate, usage time, and temperature, aging tests were performed on fresh batteries only at standard temperature to obtain the corresponding relationship between the current full-charge capacity, charge and discharge rate, and usage time of the fresh batteries at different times. Then, it was corrected according to the corresponding relationship between the DC internal resistance and temperature, and the coupling relationship between the current full-charge capacity and the charge and discharge rate, usage time, and temperature was obtained. Compared with the aging test process, the DC internal resistance test is simple and time-consuming. Therefore, this method can shorten the parameter acquisition time and further reduce the model construction cost.

[0008] In an optional embodiment, the aging test includes a cycle aging test and a calendar aging test, the usage time includes the cycle time and the shelf time, and the aging test is performed on the fresh battery at a standard temperature. The step of obtaining the fourth functional relationship includes: performing a constant power cycle aging test on the fresh battery at a preset power at a standard temperature to obtain eight functional relationships, and the eighth functional relationship is used to characterize the functional relationship between the current full-charge capacity of the fresh battery and the cycle time and the charge and discharge rate; performing a constant power calendar aging test on the fresh battery at a preset power at a standard temperature to obtain a ninth functional relationship, and the ninth functional relationship is used to characterize the functional relationship between the current full-charge capacity of the fresh battery and the shelf time; combining the eighth functional relationship and the ninth functional relationship to obtain a fourth functional relationship, and the fourth functional relationship is used to characterize the relationship between the current full-charge capacity of the fresh battery and the cycle time, the charge and discharge rate, and the shelf time.

[0009] In an optional embodiment, the step of performing an aging test on a fresh battery at a standard temperature to obtain a fifth functional relationship includes: performing a constant power cycle aging test on the fresh battery at a preset power at the standard temperature to obtain the fifth functional relationship, and the fifth functional relationship is used to characterize the relationship between the mean voltage and cycle time of the fresh battery.

[0010] In an optional embodiment, a DC internal resistance test is performed on a fresh battery at different temperature points within a preset temperature range to obtain a third functional relationship, including: at different temperature points, the fresh battery is discharged at a constant current with a preset current until the charge state of the fresh battery reaches a preset value, measuring the current DC internal resistance to obtain the DC internal resistance corresponding to each temperature; and fitting the DC internal resistance corresponding to each temperature point to obtain the third functional relationship.

[0011] In an optional embodiment, the current full-charge capacity of the fresh battery is inversely proportional to the DC internal resistance when the charge state is a preset value. The fourth functional relationship is corrected using the third functional relationship and a preset inverse proportional coefficient to obtain a seventh functional relationship.

[0012] In an optional embodiment, the battery health estimation model is established based on the ratio of the current maximum amplified energy of the battery to the rated energy, wherein the current maximum amplified energy is determined based on the product of the seventh functional relationship and the sixth functional relationship, and the rated energy is determined based on the first functional relationship.

[0013] In a second aspect, the present invention provides a battery health status estimation method, comprising: obtaining the usage time, charge and discharge rate, and ambient temperature of a battery to be tested; inputting the usage time, charge and discharge rate, and ambient temperature into a pre-established battery health estimation model to obtain a battery health status estimation result of the battery to be tested, wherein the battery health estimation model is constructed according to the method provided in any of the above embodiments.

[0014] In a third aspect, the present invention provides a device for constructing a battery health status estimation model, comprising: a first testing module for performing a constant power charge and discharge test, a constant current charge and discharge test, and a DC internal resistance test on a fresh battery at different temperature points within a preset temperature range, and obtaining a first functional relationship, a second functional relationship, and a third functional relationship, respectively. The first functional relationship, the second functional relationship, and the third functional relationship are respectively used to characterize the correspondence between the rated energy, mean voltage, DC internal resistance, and temperature of the fresh battery; a second testing module for performing an aging test on the fresh battery at a standard temperature, and obtaining a fourth functional relationship and a fifth functional relationship, respectively. The fourth functional relationship is used to characterize the correspondence between the current full charge capacity, charge and discharge rate, and usage time of the fresh battery at different times. The fifth functional relationship is used to characterize the correspondence between the mean voltage and the usage time; the function combination module is used to combine the second functional relationship and the fifth functional relationship to obtain the sixth functional relationship, and the sixth functional relationship is used to characterize the correspondence between the mean voltage, temperature, and usage time of the fresh battery; the function correction module is used to use the third functional relationship to correct the fourth functional relationship to obtain the seventh functional relationship, and the seventh functional relationship is used to characterize the correspondence between the current full-charge capacity, charge and discharge rate, usage time, and temperature; the model construction module is used to establish a battery health estimation model based on the seventh functional relationship, the sixth functional relationship, and the first functional relationship. The battery health estimation model is used to estimate the health status of the battery to be tested based on the usage time, charge and discharge rate, and ambient temperature of the battery to be tested.

[0015] In a fourth aspect, the present invention provides a battery health status estimation device, including: a data acquisition module for obtaining the usage time, charge and discharge rate and ambient temperature of the battery to be tested; a state estimation module for inputting the usage time, charge and discharge rate and ambient temperature into a battery health estimation model that has been pre-established as input values to obtain a battery health status estimation result of the battery to be tested, and the battery health estimation model is constructed according to the method provided in the above embodiment.

[0016] In a fifth aspect, the present invention provides a computer device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, computer instructions being stored in the memory, and the processor executing the computer instructions to thereby execute the battery health status estimation model construction method of the above-mentioned first aspect or any corresponding embodiment thereof, or to execute the battery health status estimation method of the above-mentioned second aspect or any corresponding embodiment thereof.

[0017] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the battery health status estimation model construction method of the above-mentioned first aspect or any corresponding embodiment thereof, or to execute the battery health status estimation method of the above-mentioned second aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 is a flowchart of a method for constructing a battery health status estimation model according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the relationship between the current full-charge capacity, cycle time, and temperature according to an embodiment of the present invention;

[0021] Figure 3 is a flowchart of a battery health status estimation method according to an embodiment of the present invention;

[0022] Figure 4 is a schematic diagram of the error of the battery health status estimation result according to an embodiment of the present invention;

[0023] Figure 5 is a structural block diagram of a device for constructing a battery health status estimation model according to an embodiment of the present invention;

[0024] Figure 6 This is a structural block diagram of a battery health status estimation device according to an embodiment of the present invention.

[0025] Figure 7 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0027] According to an embodiment of the present invention, an embodiment of a method for constructing a battery health status estimation model is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] In this embodiment, a method for constructing a battery health status estimation model is provided. Figure 1 FIG. 1 is a flow chart of a method for constructing a battery health status estimation model according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0029] In step S101, a constant power charge and discharge test, a constant current charge and discharge test, and a DC internal resistance test are performed on a fresh battery at different temperature points within a preset temperature range to obtain a first functional relationship, a second functional relationship, and a third functional relationship, respectively. The first functional relationship, the second functional relationship, and the third functional relationship are used to characterize the correspondence between the rated energy, mean voltage, DC internal resistance, and temperature of the fresh battery, respectively.

[0030] In an optional embodiment, the fresh battery refers to a battery that has not undergone charge and discharge cycles, that is, has not been used.

[0031] In an optional embodiment, the preset temperature range can be set according to the temperature in the actual battery usage environment. For example, the preset temperature range can be [0°C, 50°C], and the different temperature points can be 0°C, 10°C, 20°C, 30°C, 40°C, and 50°C.

[0032] In an optional embodiment, at each temperature point, a constant power charge and discharge test is performed on the fresh battery to obtain the rated energy corresponding to each temperature point, and then the rated energy corresponding to each temperature point is fitted to obtain a first functional relationship:

[0033] E N =p0+p1·T+p2·T 2 +p3·T 3 +p4·T 4 +p5·T 5 ,

[0034] Among them, E N represents rated energy, T represents temperature, and p0~p5, q0~q5 are parameters to be identified.

[0035] In an optional embodiment, at each temperature point, a constant current charge and discharge test is performed on the fresh battery to obtain the mean voltage corresponding to each temperature point, and then the mean voltage corresponding to each temperature point is fitted to obtain a second functional relationship:

[0036] U av =q0+q1·T+q2·T 2 +q3·T 3 +q4·T 4 +q5·T 5

[0037] Among them, U av represents the mean voltage, T represents the temperature, and p0~p5 and q0~q5 are the parameters to be identified.

[0038] In step S102, an aging test is performed on the fresh battery at a standard temperature to obtain a fourth functional relationship and a fifth functional relationship, respectively. The fourth functional relationship is used to characterize the correspondence between the current full-charge capacity, charge and discharge rate, and usage time of the fresh battery at different times. The fifth functional relationship is used to characterize the correspondence between the mean voltage and usage time.

[0039] In an optional embodiment, battery aging includes cycle aging, calendar aging, etc. When determining the correspondence between the current full charge capacity, charge and discharge rate and usage time of a fresh battery at different times, and the correspondence between the average voltage and usage time, one or more aging tests can be performed on the fresh battery.

[0040] In an optional embodiment, the standard temperature may be determined according to the battery usage environment. For example, the standard temperature may be 25°C.

[0041] Step S103: combining the second functional relationship and the fifth functional relationship to obtain a sixth functional relationship, which is used to characterize the correspondence between the average voltage, temperature, and usage time of the fresh battery.

[0042] Step S104: Using the third functional relationship to correct the fourth functional relationship, a seventh functional relationship is obtained. The seventh functional relationship is used to characterize the corresponding relationship among the current full-charge capacity, the charge and discharge rate, the usage time, and the temperature.

[0043] In an embodiment of the present invention, the fourth functional relationship is obtained by performing an aging test on a fresh battery at a standard temperature. The current full-charge capacity of the battery at different times is affected not only by the usage time and the charge and discharge rate, but also by the ambient temperature. If a battery health status estimation model is established only through the fourth functional relationship obtained at the standard temperature, the model cannot accurately estimate the battery health status considering the ambient temperature. However, if multiple aging tests are performed at multiple temperatures, it takes a long time to obtain data. Therefore, in this application, the fourth functional relationship is corrected through the third functional relationship, so that the corrected seventh functional relationship can characterize the correspondence between the current full-charge capacity and the charge and discharge rate, usage time, and temperature. In this way, there is no need to perform multiple aging tests at different temperature points, which reduces the time for obtaining data and can improve the efficiency of model construction.

[0044] Step S105 , establishing a battery health estimation model based on the seventh functional relationship, the sixth functional relationship, and the first functional relationship. The battery health estimation model is used to estimate the health status of the battery to be detected based on the usage time, charge and discharge rate, and ambient temperature of the battery to be detected.

[0045] The method for constructing a battery health state estimation model provided by an embodiment of the present invention establishes a battery health estimation model based on the seventh functional relationship, the sixth functional relationship, and the first functional relationship, wherein the seventh functional relationship represents the corresponding relationship between the current full-charge capacity, the charge and discharge rate, the usage time, and the temperature, the sixth functional relationship represents the relationship between the mean voltage and the temperature and the usage time, and the first functional relationship represents the relationship between the rated energy and the temperature. It can be seen that the model established by the embodiment of the present invention fully considers the changes in battery parameters caused by battery aging, temperature changes, and charge and discharge rate changes during use, realizes multi-factor coupling modeling, and thus improves the estimation accuracy of the battery health state estimation model. In addition, the embodiment of the present invention constructs a health state estimation model based on experimental data, without the need for complex training processes such as machine learning, thereby improving the estimation efficiency of the battery health state and reducing the cost of building the model. Furthermore, in this application, in order to determine the coupling relationship between the current full-charge capacity and the charge and discharge rate, usage time, and temperature, aging tests were performed on fresh batteries only at standard temperature to obtain the corresponding relationship between the current full-charge capacity, charge and discharge rate, and usage time of the fresh batteries at different times. Then, it was corrected according to the corresponding relationship between the DC internal resistance and temperature, and the coupling relationship between the current full-charge capacity and the charge and discharge rate, usage time, and temperature was obtained. Compared with the aging test process, the DC internal resistance test at different temperatures is simple and time-consuming. Therefore, this method can shorten the parameter acquisition time and further reduce the model construction cost.

[0046] In an optional embodiment, in step S101, when a constant power charge and discharge test is performed on a fresh battery at different temperature points within a preset temperature range to obtain a first functional relationship, the step of obtaining the rated energy of the fresh battery at any temperature includes:

[0047] In step a11, after the fresh battery is left at a preset temperature for a first preset time, the fresh battery is discharged to a second voltage at a preset constant power.

[0048] In a specific embodiment, the battery cell is left at a preset temperature for 5 hours and then discharged to 1.5V at a constant power of 1P.

[0049] Step a12: After standing for a second preset time, charge the fresh battery to a first voltage at a preset constant power; after standing for a second preset time, discharge the fresh battery to a second voltage at a preset constant power; stand for a second preset time, and record the discharge energy.

[0050] In one embodiment, after standing for 10 minutes, the battery is charged to 2.8V at a constant power of 1P, then allowed to stand for 10 minutes, and then discharged to 1.5V at a constant power of 1P, then allowed to stand for 10 minutes. The charging energy and the discharging energy at the preset temperature are recorded.

[0051] Step a13: determining the rated energy of the fresh battery at the current temperature according to the discharge energy.

[0052] In a specific embodiment, for each temperature point, step a12 may be repeated multiple times, and the average value of the discharge energy collected multiple times is used as the rated energy of the fresh battery at the temperature.

[0053] In an optional embodiment, in the above step S101, when a constant current charge and discharge test is performed on a fresh battery at different temperature points within a preset temperature range to obtain a second functional relationship, the step of obtaining the average voltage of the fresh battery at any temperature includes:

[0054] In step b11 , after the fresh battery is left at a preset temperature for a first preset time, the fresh battery is discharged to a second voltage at a preset constant current.

[0055] In one embodiment, after the battery cell is left at a preset temperature for 5 hours, it is charged at a rated current I N Discharge at constant current to 1.5V.

[0056] Step b12: After standing for a second preset time, the fresh battery is charged to a first voltage with a preset constant current; after standing for a second preset time, the fresh battery is discharged to a second voltage with a preset constant current; after standing for a second preset time, the average voltage is recorded.

[0057] In a specific embodiment, after standing for 10 minutes, the rated current I N Charge to 2.8V, let it stand for 10 minutes, and then charge at rated current I N Discharge to 1.5V, let stand for 10 minutes, and record the average voltage at the preset temperature.

[0058] In a specific embodiment, for each temperature point, step b12 may be repeated multiple times, and the average of the average voltages collected multiple times is used as the average voltage of the fresh battery at the temperature.

[0059] In an optional embodiment, in the above step S101, when the DC internal resistance of the fresh battery is tested at different temperature points within the preset temperature range to obtain the third functional relationship, the step of obtaining the DC internal resistance of the fresh battery at any temperature includes:

[0060] In step c11, at different temperature points, the fresh battery is discharged at a constant current with a preset current until the charge state of the fresh battery reaches a preset value, and the current DC internal resistance is measured to obtain the DC internal resistance corresponding to each temperature.

[0061] In one embodiment, at each temperature point, the battery is charged at a rated current I N The battery is discharged at a constant current to 50% SOC, and its DC internal resistance is measured to obtain the DC internal resistance corresponding to each temperature point.

[0062] In one embodiment, at standard temperature, the rated current I N When performing a constant current discharge test, it is considered that the battery SOC reaches 50% after 0.5h of discharge. Therefore, it is possible to determine whether the current state of charge reaches the preset value based on the constant current discharge time.

[0063] Step c12: Fitting the DC internal resistance corresponding to each temperature point to obtain a third functional relationship:

[0064] DCR=n0+n1·T+n2·T 2 +n3·T 3 +n4·T 4 +n5·T 5

[0065] DCR represents the DC internal resistance, n0~n5 are the parameters to be identified, and T is the usage time.

[0066] In an optional embodiment, the current full-charge capacity of the fresh battery and the DC internal resistance when the charge state is a preset value are inversely proportional. The fourth functional relationship is corrected using the third functional relationship and a preset inverse proportional coefficient to obtain a seventh functional relationship:

[0067]

[0068] C actual (t c ,t p ,P) represents the fourth functional relationship, q is the inverse proportional coefficient, DCR(T) represents the third functional relationship, T represents temperature, t c is the battery cycle time, t p is the battery shelf time, and P is the power.

[0069] In an optional embodiment, in the above step S102, the aging test includes a cycle aging test and a calendar aging test, and the usage time includes a cycle time and a shelf time, where the cycle time is the time in the cycle aging test and the shelf time is the time in the calendar aging test. Since the fresh battery will be damaged after an aging test is performed on it, when performing multiple different aging tests, it is necessary to perform different types of aging tests on different fresh batteries of the same model.

[0070] In the above step S102, the aging test is performed on the fresh battery at the standard temperature to obtain the fourth functional relationship, which includes:

[0071] In step d1, a constant power cycle aging test is performed on the fresh battery at a standard temperature and a preset power to obtain eight functional relationships. The eighth functional relationship is used to characterize the functional relationship between the current full charge capacity of the fresh battery and the cycle time and the charge and discharge rate.

[0072] In an optional embodiment, the process of constructing the eighth functional relationship during the cycle aging test of a fresh battery is as follows:

[0073] In step d11 , the fresh battery is left at a standard temperature for a first preset time, and then discharged at a preset constant power to a second voltage.

[0074] Step d12: After the battery is left to rest for a second preset period of time, the current full-charge capacity, average voltage, cycle time, and charge and discharge power are recorded.

[0075] Repeat step d12 until the battery discharge energy decays to a preset value, and construct an eighth functional relationship based on the current full-charge capacity, cycle time, and charge and discharge power recorded in each cycle of step d11.

[0076] In a specific embodiment, the process of constructing the eighth functional relationship by performing a cycle aging test on a fresh battery is as follows:

[0077] Step d13: keep the battery cells at a standard temperature (T ref =25℃) for 5h, then discharge to 1.5V at 1P constant power;

[0078] Step d14: Charge to 2.8V at 1P constant power, let it rest for 10 minutes, then discharge to 1.5V at 1P constant power, let it rest for 10 minutes, and record the current full charge capacity, average voltage, cycle time, and charge and discharge power;

[0079] Repeat step d14 until the battery discharge energy decays to 80% of the initial value, and construct an eighth functional relationship C based on the current full charge capacity, cycle time, and charge and discharge power recorded in each cycle of step d14. 1,actual =h(t c ,P):

[0080]

[0081] Where, ΔC 1,loss C is the battery capacity loss rate caused by cycle aging; 1,actual is the current full-charge capacity, only considering the impact of battery cycle aging; C N is the rated capacity of the battery in a fresh state; P is power, and in this embodiment, P is the preset power; E a is the battery activation energy, which is a constant; R is the gas molar constant; T ref is the standard temperature. In this embodiment, T ref =25℃; t c is the battery cycle time.

[0082] During power station operation, it is generally believed that batteries are prone to abnormalities after attenuation to 80%. Therefore, when the battery discharge energy decays to 80% of the initial value, the battery is discarded. However, for different battery types or different usage scenarios, different values can be set according to actual conditions. For example, it can be 90%, 70%, or other values of the initial value.

[0083] Step d2: performing a constant power calendar aging test on the fresh battery at a preset power at a standard temperature to obtain a ninth functional relationship, which is used to represent the functional relationship between the current full-charge capacity of the fresh battery and the shelf time.

[0084] In an optional embodiment, the process of performing a calendar aging test on a fresh battery to construct the ninth functional relationship is as follows:

[0085] In step d21 , the fresh battery is charged at a preset constant power to a first voltage.

[0086] Step d22: leaving the container at a standard temperature for a third preset time.

[0087] Step d23, discharging at a preset constant power to a second voltage, leaving the battery idle for a second preset time, recording the current full-charge capacity and the idle time, and then charging at a preset constant power to the first voltage.

[0088] Repeat steps d22 and d23 until the calendar aging test conditions are met, and construct the ninth functional relationship C according to the current full-charge capacity and the shelf time recorded in each cycle of step d23. 2,actual =h(t p ):

[0089]

[0090] Where, ΔC 2,loss C is the battery capacity loss rate caused by calendar aging; 2,actual is the full-charge capacity of the battery, considering only the impact of battery calendar aging; t p The shelf time is the time the battery is not used.

[0091] The calendar aging test condition may be that the battery discharge energy decays to a preset value, or that the number of cycles of step d22 and step d23 reaches a preset number.

[0092] In a specific embodiment, the process of performing a calendar aging test on a fresh battery to construct the ninth functional relationship is as follows:

[0093] Step d24, charging the newly used battery to 2.8V at a constant power of 1P;

[0094] Step d25, at standard temperature (T ref =25℃) for 7 days;

[0095] Step d26: discharge the battery to 1.5V at a constant power of 1P, let it rest for 10 minutes, record the current full charge capacity and rest time, and charge the battery to 2.8V at a constant power of 1P.

[0096] Repeat step d25 and step d26 until the number of cycles of step d25 and step d26 reaches a preset number, and construct a ninth functional relationship based on the current full-charge capacity and the shelf time recorded in each cycle of step d26. For example, the preset number of times can be 4 times.

[0097] Step d3: Combine the eighth functional relationship and the ninth functional relationship to obtain a fourth functional relationship, which is used to characterize the relationship between the current full-charge capacity of the fresh battery and the cycle time, charge and discharge rate, and shelf time.

[0098] In an optional embodiment, the fourth functional relationship (C actual =h(t p ,t c ,P)) is obtained by adding the eighth function relationship and the ninth function relationship:

[0099]

[0100] Where, ΔC loss C is the capacity loss rate caused by battery aging (including cycle aging and calendar aging); actual is the current full-charge capacity, which takes into account the effects of cycle aging and calendar aging; C N is the rated capacity of the fresh battery; P is the power, which is the preset power in this embodiment; E a is the battery activation energy; R is the gas molar constant; T ref is the standard temperature. In this embodiment, T ref =25℃; t c is the battery cycle time; t p is the battery shelf time. a1, a2, a3, and a4 are parameters to be identified, where a1 represents the power correction factor, a2 and a3 are the correction factors for cycle time and shelf time, respectively; and a4 is a random factor.

[0101] In an optional embodiment, the current full-charge capacity of the fresh battery and the DC internal resistance when the charge state is a preset value are inversely proportional. The fourth functional relationship is corrected using the third functional relationship and a preset inverse proportional coefficient to obtain a seventh functional relationship:

[0102]

[0103] C actual (t c ,t p ,P) represents the fourth functional relationship, q is the preset inverse proportional coefficient, and DCR(T) represents the third functional relationship.

[0104] Seventh function C actual (T,t c ,t p ,P) represents the corresponding relationship between the current full charge capacity, charge and discharge rate, usage time, and temperature. p =0, when the charge and discharge rate P=1P, the relationship between the current full charge capacity, usage time and temperature is shown in the figure below. Figure 2 shown.

[0105] In an optional embodiment, since the effect of calendar aging on the battery mean voltage is negligible, the mean voltage change is primarily affected by cycle aging and temperature. Therefore, during the cycle aging step d14 of the fresh battery, the mean voltage is simultaneously collected to obtain a fifth functional relationship representing the relationship between the mean voltage of the fresh battery and the cycle time:

[0106] U av =m0+m1·t c +m2·t c2 +m3·t c 3 +m4·t c 4 +m5·t c 5

[0107] Where U av Indicates the current average battery voltage; t c is the cycle aging time; m0~m5 are the parameters to be identified.

[0108] On this basis, the fifth functional relationship is combined with the second functional relationship, and the sixth functional relationship (U av =g(T,t c )), characterizes the correspondence between the average voltage, temperature, and usage time of a fresh battery. The usage time at this time only includes the cycle time during the cycle aging test.

[0109] In an optional embodiment, the battery health estimation model is established based on the ratio of the current maximum amplified energy of the battery to the rated energy, wherein the current maximum amplified energy is determined based on the product of the seventh functional relationship and the sixth functional relationship, and the rated energy is determined based on the first functional relationship:

[0110]

[0111] Where SOH represents the battery health state, E actual is the full charge energy of the battery in the current state, E N It is the rated energy of the fresh battery.

[0112] Among them, E actual =C actual ·U av

[0113] Where C actual is the full charge capacity of the battery in the current state; U av is the average voltage of the battery in the current state. SOH is affected by the coupling of temperature, time and charge and discharge rate, thus obtaining:

[0114]

[0115] Where C actual (T,t c ,t p ,P) is the seventh functional relationship, U av (T,t c ) is the sixth functional relationship, E N (T) is the first functional relationship.

[0116] In the embodiment of the present invention, the battery health status is estimated based on the ratio of the maximum discharge energy to the rated energy of the battery. The estimation method is more consistent with the actual operation of the power station and has a smaller estimation error.

[0117] In an optional embodiment, the energy storage station will be deeply charged and discharged after a period of use, and the time, temperature, voltage, current full charge capacity, and current full charge energy data in the battery management system are read to correct the sixth functional relationship U av =g(T,t c ) and the seventh functional relationship C actual =h(T,t c ,t p ,P) in order to realize the correction of the battery health status estimation model.

[0118] In this embodiment, a battery health status estimation method is also provided. Figure 3 Shown, including:

[0119] Step S201 , obtaining the usage time, charge and discharge rate, and ambient temperature of the battery to be tested.

[0120] In step S202, a battery health estimation result of the battery to be tested is obtained by applying the usage time, charge and discharge rate, and ambient temperature input values to a pre-established battery health estimation model. The battery health estimation model is constructed according to the battery health estimation model construction method provided in the above embodiment.

[0121] In an optional embodiment, after obtaining the battery health status estimation result, it is determined whether the life end condition of the battery to be tested is met based on the battery health status estimation result. If the life end condition is not met, steps S201 and S202 are repeated until the life end condition is not met, and then steps S201 and S202 are stopped and battery repair measures are initiated.

[0122] In a specific embodiment, the comparison between the battery health state simulation value estimated by the battery health state estimation model provided by the above embodiment and the battery health state real value is Figure 4 As shown by Figure 4 It can be seen that the error between the estimated battery health status value obtained by the method provided in the above embodiment and the true value is small.

[0123] This embodiment also provides a device for constructing a battery health state estimation model, which is used to implement the above-mentioned embodiments and preferred implementations. Details already described will not be repeated here. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

[0124] This embodiment provides a device for constructing a battery health status estimation model. Figure 5 Shown, including:

[0125] A first testing module 301 is configured to perform a constant power charge and discharge test, a constant current charge and discharge test, and a DC internal resistance test on a fresh battery at different temperature points within a preset temperature range, to obtain a first functional relationship, a second functional relationship, and a third functional relationship, respectively. The first functional relationship, the second functional relationship, and the third functional relationship are used to represent the corresponding relationship between the rated energy, mean voltage, and DC internal resistance of the fresh battery and temperature, respectively.

[0126] A second testing module 302 is configured to perform an aging test on a fresh battery at a standard temperature to obtain a fourth functional relationship and a fifth functional relationship, wherein the fourth functional relationship is configured to represent a correspondence between the current full charge capacity, the charge / discharge rate, and the usage time of the fresh battery at different times, and the fifth functional relationship is configured to represent a correspondence between the mean voltage and the usage time;

[0127] A function combining module 303 is configured to combine the second function relationship and the fifth function relationship to obtain a sixth function relationship, wherein the sixth function relationship is used to represent the correspondence between the average voltage, temperature, and usage time of the fresh battery;

[0128] a function correction module 304 for correcting the fourth function relationship using the third function relationship to obtain a seventh function relationship, wherein the seventh function relationship is used to represent the correspondence between the current full-charge capacity, the charge / discharge rate, the usage time, and the temperature;

[0129] The model building module 305 is used to establish a battery health estimation model based on the seventh functional relationship, the sixth functional relationship and the first functional relationship. The battery health estimation model is used to estimate the health status of the battery to be tested based on the usage time, charge and discharge rate, and ambient temperature of the battery to be tested.

[0130] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0131] The battery health status estimation model construction device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0132] This embodiment also provides a battery health status estimation device, which is used to implement the above-mentioned embodiments and preferred embodiments. Details that have already been described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0133] This embodiment provides a battery health status estimation device, such as Figure 6 Shown, including:

[0134] The data acquisition module 401 is used to obtain the usage time, charge and discharge rate and ambient temperature of the battery to be tested;

[0135] The state estimation module 402 is used to obtain a battery health state estimation result of the battery to be tested by applying the usage time, charge and discharge rate and ambient temperature input values to a battery health estimation model that has been pre-established. The battery health estimation model is constructed using the battery health state estimation model construction method provided in any of the above embodiments.

[0136] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0137] The embodiment of the present invention also provides a computer device having the above Figure 5 The battery health state estimation model building device shown, or having the above Figure 6 The battery health status estimation device shown.

[0138] See also Figure 7 , Figure 7 is a structural diagram of a computer device provided by an optional embodiment of the present invention, such as Figure 7As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 7 A processor 10 is taken as an example.

[0139] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0140] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0141] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0142] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0143] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Figure 7 The bus connection is taken as an example.

[0144] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0145] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0146] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for constructing a battery health status estimation model, characterized in that: The method comprises: At different temperature points within a preset temperature range, a constant power charge and discharge test, a constant current charge and discharge test, and a DC internal resistance test are performed on the fresh battery to obtain a first functional relationship, a second functional relationship, and a third functional relationship, respectively. The first functional relationship, the second functional relationship, and the third functional relationship are used to respectively characterize the correspondence between the rated energy, the mean voltage, the DC internal resistance, and the temperature of the fresh battery; Performing an aging test on the fresh battery at a standard temperature to obtain a fourth functional relationship and a fifth functional relationship, respectively. The fourth functional relationship is used to characterize the corresponding relationship between the current full charge capacity, the charge and discharge rate, and the usage time of the fresh battery at different times. The fifth functional relationship is used to characterize the corresponding relationship between the mean voltage and the usage time. Combining the second functional relationship and the fifth functional relationship to obtain a sixth functional relationship, wherein the sixth functional relationship is used to characterize the correspondence between the average voltage, temperature, and usage time of the fresh battery; The fourth functional relationship is corrected by using the third functional relationship to obtain a seventh functional relationship, wherein the seventh functional relationship is used to represent the corresponding relationship between the current full-charge capacity, the charge and discharge rate, the usage time, and the temperature; A battery health estimation model is established based on the seventh functional relationship, the sixth functional relationship and the first functional relationship. The battery health estimation model is used to estimate the health status of the battery to be detected based on the usage time, charge and discharge rate, and ambient temperature of the battery to be detected.

2. The method according to claim 1, characterized in that The aging test includes a cycle aging test and a calendar aging test, the usage time includes a cycle time and a shelf time, and the aging test is performed on the fresh battery at a standard temperature. The step of obtaining the fourth functional relationship includes: Performing a constant power cycle aging test on the fresh battery at a standard temperature and a preset power to obtain an eighth functional relationship, wherein the eighth functional relationship is used to characterize the functional relationship between the current full charge capacity of the fresh battery and the cycle time and the charge and discharge rate; Performing a constant power calendar aging test on the fresh battery at a preset power at a standard temperature to obtain a ninth functional relationship, wherein the ninth functional relationship is used to represent a functional relationship between the current full-charge capacity of the fresh battery and the shelf time; The eighth functional relationship and the ninth functional relationship are combined to obtain the fourth functional relationship, which is used to characterize the relationship between the current full-charge capacity of the fresh battery and the cycle time, charge and discharge rate, and shelf time.

3. The method according to claim 2, characterized in that The step of performing an aging test on the fresh battery at a standard temperature to obtain the fifth functional relationship includes: A constant power cycle aging test is performed on the fresh battery at a preset power under a standard temperature to obtain the fifth functional relationship, which is used to characterize the relationship between the mean voltage and cycle time of the fresh battery.

4. The method according to claim 1, wherein The step of performing a DC internal resistance test on a fresh battery at different temperature points within a preset temperature range to obtain a third functional relationship includes: At different temperature points, the fresh battery is discharged at a constant current with a preset current until the charge state of the fresh battery reaches a preset value, and the current DC internal resistance is measured to obtain the DC internal resistance corresponding to each temperature; The DC internal resistance corresponding to each temperature point is fitted to obtain the third functional relationship.

5. The method according to claim 4, characterized in that The current full-charge capacity of the fresh battery and the DC internal resistance when the charge state is a preset value are in inverse proportion. The fourth functional relationship is corrected using the third functional relationship and a preset inverse proportional coefficient to obtain a seventh functional relationship.

6. The method according to claim 1, characterized in that The battery health estimation model is established based on the ratio of the current maximum amplified energy of the battery to the rated energy, wherein the current maximum amplified energy is determined based on the product of the seventh functional relationship and the sixth functional relationship, and the rated energy is determined based on the first functional relationship.

7. A battery health status estimation method, characterized in that: include: Obtain the usage time, charge and discharge rate, and ambient temperature of the battery to be tested; A battery health estimation result of the battery to be tested is obtained by applying the usage time, charge and discharge rate and ambient temperature input values to a battery health estimation model that is pre-established. The battery health estimation model is constructed according to the method according to any one of claims 1 to 6.

8. A battery health status estimation model construction device, characterized in that: include: A first testing module is configured to perform a constant power charge and discharge test, a constant current charge and discharge test, and a DC internal resistance test on a fresh battery at different temperature points within a preset temperature range, to obtain a first functional relationship, a second functional relationship, and a third functional relationship, respectively, wherein the first functional relationship, the second functional relationship, and the third functional relationship are used to characterize the corresponding relationship between the rated energy, the mean voltage, the DC internal resistance, and the temperature of the fresh battery; a second testing module, configured to perform an aging test on the fresh battery at a standard temperature to obtain a fourth functional relationship and a fifth functional relationship, respectively, wherein the fourth functional relationship is used to characterize the correspondence between the current full-charge capacity, the charge / discharge rate, and the usage time of the fresh battery at different times, and the fifth functional relationship is used to characterize the correspondence between the mean voltage and the usage time; a function combining module, configured to combine the second functional relationship and the fifth functional relationship to obtain a sixth functional relationship, wherein the sixth functional relationship is used to characterize the correspondence between the average voltage, temperature, and usage time of the fresh battery; a function correction module, configured to correct the fourth functional relationship using the third functional relationship to obtain a seventh functional relationship, wherein the seventh functional relationship is used to characterize the correspondence between the current full-charge capacity, the charge and discharge rate, the usage time, and the temperature; A model building module is used to establish a battery health estimation model based on the seventh functional relationship, the sixth functional relationship and the first functional relationship, and the battery health estimation model is used to estimate the health status of the battery to be tested based on the usage time, charge and discharge rate, and ambient temperature of the battery to be tested.

9. A battery health status estimation device, characterized in that: include: A data acquisition module is used to obtain the usage time, charge and discharge rate, and ambient temperature of the battery to be tested; A state estimation module is used to obtain a battery health state estimation result of the battery to be tested by applying the usage time, charge and discharge rate and ambient temperature input values to a battery health estimation model pre-established, wherein the battery health estimation model is constructed according to the method according to any one of claims 1-6.

10. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the battery health state estimation model construction method according to any one of claims 1 to 6, or executes the battery health state estimation method according to claim 7 by executing the computer instructions.

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