A battery SOH estimation method and device, electronic equipment and storage medium

Abstract

The application relates to a battery SOH estimation method and device, electronic equipment and a storage medium, wherein the method comprises the following steps: establishing a sample battery capacity attenuation prediction database comprising the ratio relationship between different capacity attenuation rates of sample batteries in different preset working temperatures, different preset working current multiples and different SOH intervals; obtaining an actual temperature attenuation rate ratio and an actual current attenuation rate ratio according to the historical SOH value and the actual working condition of a battery to be measured; converting the actual unit time content change amount of the battery to be measured into a reference unit time content change amount under a reference working temperature and a reference working current multiple; and obtaining the current SOH of the battery according to the battery capacity attenuation prediction database. Compared with the prior art, the application can maintain the accuracy and estimation speed of SOH estimation under any working temperature, any working current multiple and any service life.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery SOH estimation method, apparatus, electronic device, and storage medium. Background Technology

[0002] During long-term operation, the health of lithium batteries is affected by various factors such as temperature, current rate, and depth of discharge, leading to aging. The State of Health (SOH) value is generally used to characterize the battery's ability to store energy relative to its initial new capacity; it is expressed as the percentage of the battery's current capacity to its rated capacity. The health of lithium batteries cannot be directly measured and requires the design of SOH estimation algorithms based on the analysis of various influencing factors. Currently, SOH estimation algorithms mainly include those based on electrochemical mechanisms, equivalent circuit models, and data-driven methods. Among these, the equivalent cycle number method is easier to implement and is widely used in engineering.

[0003] For example, Chinese invention patent application CN111537890A provides a battery SOH estimation method. This method comprehensively considers the effects of temperature and current on battery aging. It mainly measures the battery cycle capacity at different temperatures and cycle currents to form relationship curves between different temperatures and battery cycle capacity, as well as between different cycle currents and battery cycle capacity. Through data fitting, it obtains polynomial relationships between different temperature coefficients and temperature, and polynomial relationships between different current coefficients and current. It calculates the total influence coefficient using the temperature coefficient and current coefficient to obtain the used capacity considering the total influence coefficient, and then calculates the current SOH using the used capacity.

[0004] However, although the above method estimates the influence of temperature and current on battery aging longitudinally, it tests the battery at a fixed temperature and current rate when obtaining the temperature coefficient and current coefficient formulas. It does not consider that the rate of capacity decay is different at different aging stages under different temperatures, and therefore lacks universality. When the actual operating temperature and charge / discharge rate of the battery are inconsistent with the rate during testing, errors will occur. Summary of the Invention

[0005] In view of this, it is necessary to provide a battery SOH estimation method, apparatus, electronic device and storage medium to solve the problem that existing methods cannot accurately estimate battery SOH under different temperature and rate conditions.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for estimating the state of harmonics (SOH) of a battery, comprising:

[0008] Establish a database for predicting the capacity decay of sample batteries;

[0009] The historical SOH value, actual operating temperature, and actual operating current ratio of the battery under test are obtained, and the actual temperature decay rate ratio and the actual current decay rate ratio are obtained based on the sample battery capacity decay prediction database.

[0010] The actual capacity change per unit time of the battery under test is obtained, and the baseline capacity change per unit time of the battery under test is obtained based on the actual temperature decay rate ratio and the actual current decay rate ratio.

[0011] Based on the capacity change per unit time and the sample battery capacity decay prediction database, the actual SOH of the battery under test is obtained.

[0012] The sample battery capacity degradation prediction database includes the ratio of different capacity degradation rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges; the actual temperature degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating temperature to that at the actual operating temperature; the actual current degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating current rate to that at the actual operating current rate.

[0013] Furthermore, the establishment of the sample battery capacity degradation prediction database includes:

[0014] The cumulative capacity value of the sample battery was obtained during the decay to a preset SOH under multiple different preset operating current rates and multiple different preset operating temperatures, and a capacity change table was established.

[0015] Based on the capacity change table, the capacity decay rate of the sample battery under multiple preset operating current rates, multiple preset operating temperatures, and multiple different SOH ranges is obtained, and a decay rate table is established.

[0016] Obtain the reference operating temperature and reference operating current ratio;

[0017] Based on the decay rate table, a temperature decay rate ratio table is obtained. The temperature decay rate ratio table includes the ratio of the reference operating temperature to the capacity decay rate corresponding to the multiple different preset operating temperatures in each SOH interval under multiple different preset operating current ratios.

[0018] Based on the attenuation rate table, a current attenuation rate ratio table is obtained. The current attenuation rate ratio table includes the ratio of the reference operating current multiplier to the capacity attenuation rate corresponding to multiple different preset operating current multipliers in each SOH interval at the reference operating temperature.

[0019] The capacity change table, the temperature decay rate ratio table, and the current decay rate ratio table constitute the battery capacity decay prediction database.

[0020] Furthermore, the step of obtaining the historical SOH value, actual operating temperature, and actual operating current ratio of the battery under test, and obtaining the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database, includes:

[0021] Obtain the actual operating temperature and actual operating current ratio of the battery under test;

[0022] Obtain the latest historical SOH value of the battery under test as the baseline SOH value;

[0023] Based on the actual operating temperature, actual operating current ratio, and reference SOH value of the battery under test, and using the temperature decay rate ratio table, the actual temperature decay rate ratio of the battery under test at the actual operating current ratio is obtained.

[0024] Based on the actual operating current ratio of the battery under test and the reference SOH value, the actual current decay rate ratio is obtained according to the current decay rate ratio table.

[0025] Furthermore, the step of obtaining the actual temperature decay rate ratio of the battery under test at the actual operating current ratio based on the actual operating temperature, actual operating current ratio, and the reference SOH value of the battery under test, and according to the temperature decay rate ratio table, includes:

[0026] Based on the actual operating current ratio, select the two preset operating current ratios that are closest to the actual operating current ratio in the temperature decay rate ratio table as reference current ratios;

[0027] The ratio of the capacity decay rate corresponding to the two reference current ratios is selected from the SOH range where the reference SOH value is located and the preset operating temperature is closest to the actual operating temperature in the temperature decay rate ratio table.

[0028] The actual temperature decay rate ratio is obtained based on the reference current multiplier, the reference ratio, and the actual operating current multiplier.

[0029] Furthermore, the step of obtaining the actual current decay rate ratio based on the actual operating current ratio of the battery under test and the reference SOH value, using the current decay rate ratio table, includes:

[0030] Select the preset operating current ratio that is closest to the actual operating current ratio within the SOH range where the reference SOH value is located in the current decay rate ratio table;

[0031] The ratio of the capacity decay rate corresponding to the preset operating current ratio that is closest to the actual operating current ratio is taken as the actual current decay rate ratio.

[0032] Furthermore, obtaining the actual capacity change of the battery under test per unit time, and obtaining the baseline capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio, includes:

[0033] Obtain the actual capacity change per unit time of the battery under test at the actual operating temperature and actual operating current rate;

[0034] Based on the actual capacity change of the battery under test at the actual operating temperature and actual operating current rate, and based on the actual temperature decay rate ratio, the capacity change of the battery under test at the reference operating temperature and actual operating current rate is obtained.

[0035] Based on the capacity change of the battery under test at the reference operating temperature and the actual operating current ratio per unit time, and based on the actual current decay rate ratio, the capacity change of the battery under test at the reference operating temperature and the reference operating current ratio per unit time is obtained, and is used as the reference capacity change per unit time.

[0036] Furthermore, obtaining the actual SOH of the battery under test based on the baseline capacity change per unit time and the sample battery capacity decay prediction database includes:

[0037] Based on the capacity change per unit time, the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate is obtained.

[0038] The actual SOH of the battery under test is obtained based on the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate, and the battery capacity decay prediction database.

[0039] Secondly, the present invention also provides a battery SOH estimation device, comprising:

[0040] The model building module is used to build a database for predicting the capacity decay of sample batteries.

[0041] The parameter selection module is used to obtain the historical SOH value, actual operating temperature and actual operating current ratio of the battery under test, and to obtain the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database.

[0042] The change conversion module is used to obtain the actual capacity change of the battery under test per unit time, and to obtain the reference capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio.

[0043] The estimation module is used to obtain the actual SOH of the battery under test based on the capacity change per unit time of the benchmark and the sample battery capacity decay prediction database.

[0044] The sample battery capacity degradation prediction database includes the ratio of different capacity degradation rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges; the actual temperature degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating temperature to that at the actual operating temperature; the actual current degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating current rate to that at the actual operating current rate.

[0045] Thirdly, the present invention also provides an electronic device, including a memory and a processor, wherein,

[0046] The memory is used to store programs;

[0047] The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in any of the above-described battery SOH estimation methods.

[0048] Fourthly, the present invention also provides a computer-readable storage medium, characterized in that it is used to store a computer-readable program or instructions, which, when executed by a processor, are capable of implementing the steps in any of the above-described battery SOH estimation methods.

[0049] This invention provides a battery SOH estimation method, apparatus, electronic device, and storage medium. The method establishes a sample battery capacity decay prediction database, which includes the ratio relationships between different capacity decay rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges. Based on the historical SOH values ​​and actual operating conditions of the battery under test, the method obtains the actual temperature decay rate ratio and the actual current decay rate ratio. Then, it converts the actual capacity change per unit time of the battery under test into the benchmark capacity change per unit time under the benchmark operating temperature and benchmark operating current rate. Finally, based on the battery capacity decay prediction database, the current SOH of the battery is obtained. Compared to existing technologies, this invention constructs a sample battery capacity decay prediction database to obtain the decay rate ratio relationship of batteries at different aging capacity decay stages, different temperatures, and different current rates. It realizes the conversion of the capacity change per unit time under any operating condition into the capacity change per unit time of a benchmark, and thus can quickly obtain the SOH value with a unified standard. It not only takes into account the different decay conditions of batteries at different temperatures and current rates, but also considers the differences in decay rate at different decay stages. This allows the method to maintain accuracy and estimation speed under any operating temperature, any operating current rate, and any service life. Attached Figure Description

[0050] Figure 1 A flowchart illustrating an embodiment of the battery SOH estimation method provided by the present invention;

[0051] Figure 2 for Figure 1 A flowchart of a method according to an embodiment of step S101;

[0052] Figure 3 for Figure 1 A flowchart of a method according to an embodiment of step S102;

[0053] Figure 4 This is a schematic diagram of an embodiment of the battery SOH estimation device provided by the present invention;

[0054] Figure 5 A schematic diagram of the structure of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0055] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0056] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] This invention constructs a sample battery capacity decay prediction database to obtain the decay rate ratio relationship of batteries at different aging capacity decay stages, different temperatures, and different current rates. It realizes the conversion of the capacity change per unit time under any operating condition into the base capacity change per unit time of the battery at the base operating temperature and base operating current rate, thereby enabling the SOH value to be obtained with a unified standard, improving the accuracy and speed of SOH estimation.

[0059] Specifically, the present invention provides a battery SOH estimation method, apparatus, electronic device, and storage medium, which are described below.

[0060] Combination Figure 1 As shown in the figure, a specific embodiment of the present invention discloses a method for estimating the state of harmonics (SOH) of a battery, the method comprising:

[0061] S101. Establish a database for predicting the capacity decay of sample batteries;

[0062] S102. Obtain the historical SOH value, actual operating temperature and actual operating current ratio of the battery under test, and obtain the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database.

[0063] S103. Obtain the actual capacity change of the battery under test per unit time, and obtain the baseline capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio.

[0064] S104. Based on the capacity change per unit time and the sample battery capacity decay prediction database, obtain the actual SOH of the battery under test;

[0065] The sample battery capacity degradation prediction database includes the ratio of different capacity degradation rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges; the actual temperature degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating temperature to that at the actual operating temperature; the actual current degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating current rate to that at the actual operating current rate.

[0066] This invention provides a battery SOH estimation method. It establishes a sample battery capacity decay prediction database, including ratios between different capacity decay rates of sample batteries at different preset operating temperatures, different preset operating current rates, and different SOH ranges. Based on the historical SOH values ​​and actual operating conditions of the battery under test, it obtains the actual temperature decay rate ratio and the actual current decay rate ratio. Then, it converts the actual capacity change per unit time of the battery under test into a baseline capacity change per unit time at a baseline operating temperature and baseline operating current rate. Finally, based on the battery capacity decay prediction database, it obtains the current SOH of the battery.

[0067] This method not only considers the impact of temperature and different current rates on battery aging, but also takes into account the degradation rate changes at different stages of cell aging, thus improving the accuracy of SOH estimation. Furthermore, this method first processes the cell capacity degradation data, i.e., the capacity change per unit time, converting data from different operating temperatures to data at a reference temperature, and data from different current rates to data at a reference operating current rate. This facilitates real-time and rapid retrieval of the current SOH using a unified standard, thereby improving the speed of SOH estimation.

[0068] Combination Figure 2 As shown, in a preferred embodiment, step S101 of this embodiment, establishing a sample battery capacity degradation prediction database, includes:

[0069] S201. Obtain the cumulative capacity value change of the sample battery during the decay to a preset SOH under multiple different preset operating current rates and multiple different preset operating temperatures, and establish a capacity change table.

[0070] S202. Based on the capacity change table, obtain the capacity decay rate of the sample battery under multiple different preset operating current rates, multiple different preset operating temperatures, and multiple different SOH ranges, and establish a decay rate table.

[0071] S203. Obtain the reference operating temperature and reference operating current ratio;

[0072] S204. Based on the attenuation rate table, a temperature attenuation rate ratio table is obtained. The temperature attenuation rate ratio table includes the ratio of the reference operating temperature to the capacity attenuation rate corresponding to the multiple different preset operating temperatures in each SOH interval under multiple different preset operating current ratios.

[0073] S205. Based on the attenuation rate table, a current attenuation rate ratio table is obtained. The current attenuation rate ratio table includes the ratio of the reference operating current multiplier to the capacity attenuation rate corresponding to multiple different preset operating current multipliers in each SOH interval at the reference operating temperature.

[0074] The capacity change table, the temperature decay rate ratio table, and the current decay rate ratio table constitute the battery capacity decay prediction database.

[0075] For ease of understanding, the present invention also provides a more specific embodiment to illustrate the above steps S201 to S205:

[0076] First, it should be noted that in this embodiment, a base operating temperature of 25°C and a base operating current ratio of 1C are used. In practice, the specific values ​​of these two values ​​can be flexibly changed as needed. Furthermore, this invention applies to both batteries and battery cells; for ease of explanation, the terms "battery" and "battery cell" will not be distinguished in the following text.

[0077] First, take 2-3 new cells of the same model as the battery under test at each temperature and rate, and perform the following tests respectively to reduce the impact of individual cell differences on the test data and avoid test data failure due to individual cell abnormalities or test abnormalities.

[0078] 1.1. Based on the common operating environment of lithium battery systems, select different operating temperature points, such as -30℃, -10℃, 0℃, 10℃, 25℃, 40℃, 60℃, etc.

[0079] 1.2. Select different operating current ratios, such as 1 / 3C, 1C, 3C, 5C, etc., according to the common operating conditions of lithium battery systems;

[0080] 1.3. Fully charge the battery cells at room temperature;

[0081] 1.4 Store at the specified operating temperature for a period of time;

[0082] 1.5. At the specified temperature, discharge at a constant current rate at the specified operating current ratio until the cell discharge cutoff voltage is reached;

[0083] 1.6. Let it stand for a period of time at the specified temperature;

[0084] 1.7 At the specified temperature, charge the battery cell at the specified rate using a constant current until the cell charging cutoff voltage is reached;

[0085] 1.8. Perform the test in a cycle of the above process 1.4 to 1.7. Every N cycles, test the current standard capacity of the cell according to the standard capacity test method and calculate the SOH at this time until the capacity decays to about 50% of the cell's rated capacity, that is, decays to the preset SOH.

[0086] 1.9 Complete steps 1.3 to 1.8 at the specified temperature and current rate specified in steps 1-2 and obtain the cell cycle decay test data record. Obtain the relationship table between the change of the cumulative capacity value of the cell and the corresponding change of SOH at each operating temperature and operating rate, as the capacity change table Table_orig.

[0087] It is understood that cumulative capacity is a well-known concept to those skilled in the art, and the specific start and end times of accumulation can be flexibly adjusted according to specific circumstances. As a preferred embodiment, the cumulative time in this embodiment refers to the total cumulative capacity of the battery from the time it leaves the factory to the current test moment, that is, the sum of the charge / discharge capacity of the current cycle and each previous cycle up to the current cycle. In practice, it can also refer to the total charge / discharge capacity of the cell in a single cycle, or the charge / discharge capacity over any given period, etc. Furthermore, the above process is only for illustrating the data format of the attenuation rate table in this embodiment and does not limit the means of obtaining this data. In practice, other means such as simulation can also be used to obtain this data.

[0088] 2.1 After obtaining the above capacity change table Table_orig, the cell capacity decay table under each rate is processed as follows in 2.2-2.4;

[0089] 2.2 At the temperatures mentioned above, using 5% SOH as a SOH interval, the current cumulative capacity is obtained at 5% SOH intervals, resulting in Table_c, which shows the cell throughput at each operating temperature under the same operating current rate. For example, 95% SOH corresponds to cumulative capacity C1, and 90% SOH corresponds to cumulative capacity C2.

[0090] 2.3. Based on the cell throughput table Table_c, calculate the capacity decay rate for every 5% SOH (State of Harmonic Oxide) decay, i.e., the slope of the SOH change corresponding to the cumulative capacity change within each SOH range. This yields a set of capacity decay rates corresponding to each operating temperature at the same operating current ratio. For example, within the 95%-90% SOH range, the capacity decay rate is (C2-C1) / 5.

[0091] 2.4 After processing the data for each operating current ratio through steps 2.2-2.4, the capacity decay rate corresponding to each operating current ratio and each operating temperature is summarized to obtain the decay rate table Table_rc.

[0092] 2.5. Based on the attenuation rate Table_rc, at each operating current rate, the capacity attenuation rate at 25°C (5% SOH) is compared with the capacity attenuation rate at different temperatures to obtain the temperature attenuation rate ratio at different temperatures, thus obtaining the temperature attenuation rate ratio table Table_rr. For example, within the 95%-90% SOH range, the cell capacity at -10°C is R1, and at 25°C is R2. The temperature attenuation rate ratio at -10°C to 25°C is R2 / R1, meaning the temperature attenuation rate ratio at room temperature is always 1. In this embodiment, the selected temperature attenuation rate ratio is used to convert the capacity attenuation rate at the actual operating current rate and actual temperature to the temperature attenuation rate at the actual operating current rate and room temperature.

[0093] 2.6 Extract the attenuation rate of each segment at 5% SOH at room temperature (25℃) from Table_rc to obtain Table_rc_C, which shows the attenuation rate of the battery cell at room temperature but at different operating current ratios.

[0094] 2.7 Referring to the method in 2.5, in the room temperature decay rate table Table_rc_C, calculate the ratio of the decay rate at 1C to the decay rate at different ratios, and use this as the current decay rate ratio to obtain the current decay rate ratio table Table_rr_1C. The data in the table are as follows: at 25℃, within the range of 95%-90% SOH, the cell capacity decay rate at 1 / 3C is R1, and the cell capacity decay rate at 1C is R2. The decay rate ratio from 1 / 3C to 1C is R2 / R1, which means the capacity decay rate ratio at room temperature is 1. In this embodiment, the selected current decay rate ratio is used to convert the capacity decay rate at the actual operating current ratio and room temperature to the temperature decay rate at 1C and room temperature.

[0095] The capacity change table Table_orig, the temperature decay rate ratio table Table_rr, and the current decay rate ratio table Table_rc_C obtained in the above steps constitute the battery capacity decay prediction database to be established in step S101. The above processing can be implemented using a computer, such as database software, to improve processing efficiency. Specific implementation methods are existing technologies and will not be elaborated upon in this paper.

[0096] Furthermore, in combination Figure 3 As shown, in a preferred embodiment, step S102, obtaining the historical SOH value, actual operating temperature, and actual operating current ratio of the battery under test, and obtaining the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database, specifically includes:

[0097] S301. Obtain the actual operating temperature and actual operating current rate of the battery under test;

[0098] S302. Obtain the latest historical SOH value of the battery under test as the baseline SOH value;

[0099] S303. Based on the actual operating temperature, actual operating current ratio, and reference SOH value of the battery under test, and using the temperature decay rate ratio table, obtain the actual temperature decay rate ratio of the battery under test at the actual operating current ratio.

[0100] S304. Based on the actual operating current ratio of the battery under test and the reference SOH value, the actual current decay rate ratio is obtained according to the current decay rate ratio table.

[0101] Specifically, before performing step S301 in this embodiment, it is necessary to perform debouncing processing on the cell temperature and current. Different debouncing algorithms, such as low-pass filtering, can be selected according to the actual situation. This invention will not describe them in detail here.

[0102] In step S302 of this embodiment, the most recent SOH value is selected from the previously measured SOH values ​​of the battery under test as the baseline SOH value. Subsequent judgments are then made based on this baseline SOH value, with the baseline SOH set to 100% for the first estimation. Since the final SOH value is determined with reference to historical data, this process can be repeated. Therefore, this method, to some extent, achieves closed-loop adjustment in the estimation process. By introducing the previous SOH value, each estimation is based on the previous SOH value, avoiding abnormal jumps in SOH, maintaining a smooth change in SOH, and improving accuracy.

[0103] Specifically, in a preferred embodiment, step S303 of this embodiment, obtaining the actual temperature decay rate ratio of the battery under test at the actual operating current ratio based on the actual operating temperature, actual operating current ratio, and the reference SOH value of the battery under test, and according to the temperature decay rate ratio table, specifically includes:

[0104] Based on the actual operating current ratio, select the two preset operating current ratios that are closest to the actual operating current ratio in the temperature decay rate ratio table as reference current ratios;

[0105] The ratio of the capacity decay rate corresponding to the two reference current ratios is selected from the SOH range where the reference SOH value is located and the preset operating temperature is closest to the actual operating temperature in the temperature decay rate ratio table.

[0106] The actual temperature decay rate ratio is obtained based on the reference current multiplier, the reference ratio, and the actual operating current multiplier.

[0107] In a preferred embodiment, step S304, obtaining the actual current decay rate ratio based on the actual operating current ratio of the battery under test and the reference SOH value, according to the current decay rate ratio table, specifically includes:

[0108] Select the preset operating current ratio that is closest to the actual operating current ratio within the SOH range where the reference SOH value is located in the current decay rate ratio table;

[0109] The ratio of the capacity decay rate corresponding to the preset operating current ratio that is closest to the actual operating current ratio is taken as the actual current decay rate ratio.

[0110] The present invention also provides a preferred embodiment to illustrate steps S303 and S304 in more detail:

[0111] First, the SOH is divided into multiple levels according to each SOH range, which is 5% in this embodiment, and is respectively denoted as Level 1, Level 2, Level 3, Level 4, Level 5... For example, 100%-95% is Level 1, 95%-90% is Level 2, and so on.

[0112] Then, in the temperature degradation rate ratio table Table_rr, the two current ratios that are closest to the actual operating current ratio, i.e., the current operating current ratio of the battery, are taken as the entries corresponding to the reference ratios CRmax and CRmin. The entry corresponding to the higher ratio CRmax is Table_rr_max, which includes the ratio of capacity degradation rate at room temperature and different temperatures at the CRmax current ratio; the entry corresponding to the lower ratio CRmin is Table_rr_min, which includes the ratio of capacity degradation rate at room temperature and different temperatures at the CRmin current ratio.

[0113] From the entries Table_rr_max and Table_rr_min above, the ratios within the SOH range corresponding to the historical SOH values ​​(Levelx) at the temperature closest to the actual operating temperature CurrTemp are selected to obtain two reference ratios: the high-rate attenuation ratio Rate_NT_max and the low-rate attenuation ratio Rate_NT_min. The specific expressions are as follows:

[0114] Rate_NT_max=Table_rr_max(CurrTemp,Levelx)

[0115] Rate_NT_min=Table_rr_min(CurrTemp,Levelx)

[0116] Based on the two reference magnifications and reference ratios mentioned above, the actual temperature decay rate ratio Rate_NT can be obtained:

[0117]

[0118] The aforementioned actual temperature decay rate ratio Rate_NT can convert the decay rate of the battery under test into the decay rate ratio at room temperature (i.e., the reference operating temperature). However, the decay rate at room temperature is the decay rate ratio at the current actual operating current ratio, so further processing is still required.

[0119] From the current decay rate ratio table Table_rr_1C above, select the existing ratio CurrCR that is closest to the current actual operating current ratio of the battery under test as the preset operating current ratio. Select the capacity decay rate ratio corresponding to the preset operating current ratio that is located in the SOH interval corresponding to the level Levelx based on the historical SOH value as the required actual current decay rate ratio Rate_CurrCR, and its expression is as follows:

[0120] Rate_CurrCR=Table_rr_1C(CurrCR, Levelx)

[0121] The aforementioned actual current decay rate ratio Rate_CurrCR can further convert the decay rate ratio of the battery under test at room temperature (i.e., the reference operating temperature) into the decay rate ratio at room temperature and 1C (i.e., the reference operating current ratio) operating current ratio.

[0122] The change in battery capacity per unit time can be considered as the battery's capacity decay rate. This change in capacity per unit time can be obtained by integrating the current in ampere-hours (AHs), which is well-known to those skilled in the art and will not be elaborated upon here. Therefore, after obtaining the actual temperature decay rate ratio and the actual current decay rate ratio, step S103 can be performed to convert the actual change in capacity per unit time into a baseline change in capacity per unit time at a baseline operating temperature and a baseline operating current ratio, thereby accurately estimating the SOH (State of Harm).

[0123] In a preferred embodiment, step S103 of this embodiment, obtaining the actual capacity change of the battery under test per unit time, and obtaining the baseline capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio, specifically includes:

[0124] Obtain the actual capacity change per unit time of the battery under test at the actual operating temperature and actual operating current rate;

[0125] Based on the actual capacity change of the battery under test at the actual operating temperature and actual operating current rate, and based on the actual temperature decay rate ratio, the capacity change of the battery under test at the reference operating temperature and actual operating current rate is obtained.

[0126] Based on the capacity change of the battery under test at the reference operating temperature and the actual operating current ratio per unit time, and based on the actual current decay rate ratio, the capacity change of the battery under test at the reference operating temperature and the reference operating current ratio per unit time is obtained, and is used as the reference capacity change per unit time.

[0127] The specific expression for the above process is:

[0128] ΔC_NTemp1C=ΔC_CurrTemp*Rate_NT*Rate_CurrCR

[0129] In the formula, ΔC_CurrTemp represents the actual capacity change per unit time, and ΔC_NTemp1C represents the capacity change per reference unit time.

[0130] After obtaining the above-mentioned baseline capacity change per unit time, step S104 can be performed. In a preferred embodiment, step S104, based on the baseline capacity change per unit time and the sample battery capacity decay prediction database, obtains the actual SOH of the battery under test, specifically including:

[0131] Based on the capacity change per unit time, the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate is obtained.

[0132] The actual SOH of the battery under test is obtained based on the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate, and the battery capacity decay prediction database.

[0133] In a more specific embodiment of the above process, the change in capacity per unit time can be integrated to obtain the cumulative capacity C_NTemp1C at room temperature 1°C:

[0134]

[0135] The cumulative capacity in this step has the same meaning as the cumulative capacity when establishing the capacity change table Table_orig in the previous process. That is, the value of t in the above formula is the time interval from the manufacturing time of the battery under test to the current test time. Similarly, it can be understood that in actual implementation, the specific value of t can also be flexibly set.

[0136] After obtaining the cumulative capacity C_NTemp1C, you can select the SOH value corresponding to the cumulative capacity C_NTemp1C at room temperature and 1C from the capacity change table Table_orig. This is the final SOH value that is closest to the actual current condition of the battery under test. The specific expression is as follows:

[0137] SOH=Table_orig(25℃,1C,C_NTemp1C)

[0138] In summary, the method in this embodiment considers the impact of temperature and different capacity rates on battery aging, and takes into account the degradation rate changes at different stages of cell aging, thus improving the accuracy of State of Health (SOH). Furthermore, this method first processes the cell capacity degradation data, converting different temperatures into capacity degradation rates at room temperature, facilitating real-time SOH estimation under actual battery pack temperature and current variations, thereby improving the speed of SOH estimation. Finally, this embodiment also employs closed-loop SOH adjustment, incorporating the previous SOH value to prevent abnormal SOH jumps and maintain a smooth SOH change.

[0139] To better implement the battery SOH estimation method in the embodiments of the present invention, based on the battery SOH estimation method, please refer to the corresponding documentation. Figure 4 , Figure 4 This is a schematic diagram of an embodiment of the battery SOH estimation device provided by the present invention. The battery SOH estimation device 400 provided in this embodiment includes:

[0140] Model building module 410 is used to build a database for predicting the capacity decay of sample batteries.

[0141] The parameter selection module 420 is used to obtain the historical SOH value, actual operating temperature and actual operating current ratio of the battery under test, and to obtain the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database.

[0142] The change conversion module 430 is used to obtain the actual capacity change of the battery under test per unit time, and to obtain the reference capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio.

[0143] The estimation module 440 is used to obtain the actual SOH of the battery under test based on the capacity change per unit time of the benchmark and the sample battery capacity decay prediction database.

[0144] It should be noted that the corresponding device 400 provided in the above embodiments can implement the technical solutions described in the above method embodiments. The specific implementation principles of the above modules or units can be found in the corresponding content in the above method embodiments, and will not be repeated here.

[0145] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Based on the above-described battery SOH estimation method, the present invention also provides a battery SOH estimation device 500, namely the aforementioned electronic device. The battery SOH estimation device 500 can be a computing device such as a mobile terminal, desktop computer, laptop, handheld computer, or server. The battery SOH estimation device 500 includes a processor 510, a memory 520, and a display 530. Figure 5 Only a portion of the components of the battery SOH estimation device are shown; however, it should be understood that implementation of all shown components is not required, and more or fewer components may be implemented instead.

[0146] In some embodiments, the memory 520 may be an internal storage unit of the battery SOH estimation device 500, such as a hard disk or RAM of the battery SOH estimation device 500. In other embodiments, the memory 520 may be an external storage device of the battery SOH estimation device 500, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the battery SOH estimation device 500. Furthermore, the memory 520 may include both internal and external storage units of the battery SOH estimation device 500. The memory 520 is used to store application software and various types of data installed on the battery SOH estimation device 500, such as the program code for installing the battery SOH estimation device 500. The memory 520 may also be used to temporarily store data that has been output or will be output. In one embodiment, the memory 520 stores a battery SOH estimation program 540, which can be executed by the processor 510 to implement the battery SOH estimation methods of the various embodiments of this application.

[0147] In some embodiments, processor 510 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 520 or process data, such as executing a battery SOH estimation method.

[0148] In some embodiments, display 530 may be an LED display, a liquid crystal display, a touch-screen liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 530 is used to display information from the battery SOH estimation device 500 and to display a visual user interface. Components 510-530 of the battery SOH estimation device 500 communicate with each other via a system bus.

[0149] In one embodiment, when the processor 510 executes the battery SOH estimation program 540 in the memory 520, the steps in the battery SOH estimation method described above are implemented.

[0150] This embodiment also provides a computer-readable storage medium storing a battery SOH estimation program, which, when executed by a processor, can implement the steps in the above embodiments.

[0151] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for estimating the state of harmonics (SOH) of a battery, characterized in that, include: Establishing a sample battery capacity degradation prediction database includes: acquiring the cumulative capacity value change of the sample battery during degradation to a preset SOH under multiple different preset operating current ratios and multiple different preset operating temperatures, and establishing a capacity change table; based on the capacity change table, obtaining the capacity degradation rate of the sample battery under multiple different preset operating current ratios and multiple different preset operating temperatures in multiple different SOH intervals, and establishing a degradation rate table; acquiring a reference operating temperature and a reference operating current ratio; based on the degradation rate table, obtaining a temperature degradation rate ratio table, which includes the ratio of the reference operating temperature to the capacity degradation rate corresponding to multiple different preset operating temperatures in each SOH interval under multiple different preset operating current ratios; based on the degradation rate table, obtaining a current degradation rate ratio table, which includes the ratio of the reference operating current ratio to the capacity degradation rate corresponding to multiple different preset operating current ratios in each SOH interval under the reference operating temperature; wherein, the capacity change table, the temperature degradation rate ratio table, and the current degradation rate ratio table constitute the battery capacity degradation prediction database; The historical SOH value, actual operating temperature, and actual operating current ratio of the battery under test are obtained, and the actual temperature decay rate ratio and the actual current decay rate ratio are obtained based on the sample battery capacity decay prediction database. The actual capacity change per unit time of the battery under test is obtained, and the baseline capacity change per unit time of the battery under test is obtained based on the actual temperature decay rate ratio and the actual current decay rate ratio. Based on the capacity change per unit time and the sample battery capacity decay prediction database, the actual SOH of the battery under test is obtained. The sample battery capacity degradation prediction database includes the ratio of different capacity degradation rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges; the actual temperature degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating temperature to that at the actual operating temperature; the actual current degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating current rate to that at the actual operating current rate.

2. The battery SOH estimation method according to claim 1, characterized in that, The process of acquiring the historical SOH value, actual operating temperature, and actual operating current ratio of the battery under test, and obtaining the actual temperature decay rate ratio and actual current decay rate ratio based on the sample battery capacity decay prediction database, includes: Obtain the actual operating temperature and actual operating current ratio of the battery under test; Obtain the latest historical SOH value of the battery under test as the baseline SOH value; Based on the actual operating temperature, actual operating current ratio, and reference SOH value of the battery under test, and using the temperature decay rate ratio table, the actual temperature decay rate ratio of the battery under test at the actual operating current ratio is obtained. Based on the actual operating current ratio of the battery under test and the reference SOH value, the actual current decay rate ratio is obtained according to the current decay rate ratio table.

3. The battery SOH estimation method according to claim 2, characterized in that, The step of obtaining the actual temperature decay rate ratio of the battery under test at the actual operating current ratio based on the actual operating temperature, actual operating current ratio, and the reference SOH value of the battery under test, and according to the temperature decay rate ratio table, includes: Based on the actual operating current ratio, select the two preset operating current ratios that are closest to the actual operating current ratio in the temperature decay rate ratio table as reference current ratios; The ratio of the capacity decay rate corresponding to the two reference current ratios is selected from the SOH range where the reference SOH value is located and the preset operating temperature is closest to the actual operating temperature in the temperature decay rate ratio table. The actual temperature decay rate ratio is obtained based on the reference current multiplier, the reference ratio, and the actual operating current multiplier.

4. The battery SOH estimation method according to claim 2, characterized in that, The step of obtaining the actual current decay rate ratio based on the actual operating current ratio of the battery under test and the reference SOH value, using the current decay rate ratio table, includes: Select the preset operating current ratio that is closest to the actual operating current ratio within the SOH range where the reference SOH value is located in the current decay rate ratio table; The ratio of the capacity decay rate corresponding to the preset operating current ratio that is closest to the actual operating current ratio is taken as the actual current decay rate ratio.

5. The battery SOH estimation method according to claim 1, characterized in that, The step of obtaining the actual capacity change of the battery under test per unit time, and obtaining the baseline capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio, includes: Obtain the actual capacity change per unit time of the battery under test at the actual operating temperature and actual operating current rate; Based on the actual capacity change of the battery under test at the actual operating temperature and actual operating current rate, and based on the actual temperature decay rate ratio, the capacity change of the battery under test at the reference operating temperature and actual operating current rate is obtained. Based on the capacity change of the battery under test at the reference operating temperature and the actual operating current ratio per unit time, and based on the actual current decay rate ratio, the capacity change of the battery under test at the reference operating temperature and the reference operating current ratio per unit time is obtained, and is used as the reference capacity change per unit time.

6. The battery SOH estimation method according to claim 5, characterized in that, The step of obtaining the actual SOH of the battery under test based on the capacity change per unit time and the sample battery capacity decay prediction database includes: Based on the capacity change per unit time, the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate is obtained. The actual SOH of the battery under test is obtained based on the cumulative capacity of the battery under test at the reference operating temperature and reference operating current rate, and the battery capacity decay prediction database.

7. A battery SOH estimation device, characterized in that, include: The model building module is used to establish a sample battery capacity degradation prediction database, including: obtaining the cumulative capacity value change of the sample battery during degradation to a preset SOH under multiple different preset operating current ratios and multiple different preset operating temperatures, and establishing a capacity change table; based on the capacity change table, obtaining the capacity degradation rate of the sample battery under multiple different preset operating current ratios and multiple different preset operating temperatures in multiple different SOH intervals, and establishing a degradation rate table; obtaining a reference operating temperature and a reference operating current ratio; based on the degradation rate table, obtaining a temperature degradation rate ratio table, which includes the ratio of the reference operating temperature to the capacity degradation rate corresponding to multiple different preset operating temperatures in each SOH interval under multiple different preset operating current ratios; based on the degradation rate table, obtaining a current degradation rate ratio table, which includes the ratio of the reference operating current ratio to the capacity degradation rate corresponding to multiple different preset operating current ratios in each SOH interval under the reference operating temperature; wherein, the capacity change table, the temperature degradation rate ratio table, and the current degradation rate ratio table constitute the battery capacity degradation prediction database; The parameter selection module is used to obtain the historical SOH value, actual operating temperature and actual operating current ratio of the battery under test, and to obtain the actual temperature decay rate ratio and the actual current decay rate ratio based on the sample battery capacity decay prediction database. The change conversion module is used to obtain the actual capacity change of the battery under test per unit time, and to obtain the reference capacity change of the battery under test per unit time based on the actual temperature decay rate ratio and the actual current decay rate ratio. The estimation module is used to obtain the actual SOH of the battery under test based on the capacity change per unit time of the benchmark and the sample battery capacity decay prediction database. The sample battery capacity degradation prediction database includes the ratio of different capacity degradation rates of sample batteries under different preset operating temperatures, different preset operating current rates, and different SOH ranges; the actual temperature degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating temperature to that at the actual operating temperature; the actual current degradation rate ratio is used to characterize the ratio of the battery's capacity degradation rate at the reference operating current rate to that at the actual operating current rate.

8. An electronic device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the battery SOH estimation method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, are capable of implementing the steps in the battery SOH estimation method according to any one of claims 1 to 6.

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