Impedance detection method, device, equipment, medium and product

Abstract

The invention discloses an impedance detection method, device and equipment, a medium and a product, and the method comprises the steps: obtaining a state parameter of a battery, the state parameter comprising the current temperature of the battery; determining a target impedance characteristic parameter corresponding to the state parameter, wherein the target impedance characteristic parameter comprises characteristic data at an inflection point where the impedance changes along with the temperature; and determining the current impedance of the battery based on the current temperature and the target impedance characteristic parameter. Therefore, the current impedance of the battery can be comprehensively detected based on the current temperature of the battery and the characteristic data of the inflection point where the impedance changes along with the temperature, so that accurate detection of the impedance of the battery is realized.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to an impedance detection method, device, equipment, medium, and product. Background Technology

[0002] Battery impedance detection is key to achieving precise battery health management and intelligent operation and maintenance.

[0003] Impedance testing of batteries can reveal battery aging trends in advance, identify capacity decay and safety hazards, optimize charging and discharging strategies, extend lifespan, and reduce the risk of thermal runaway.

[0004] Therefore, an accurate battery impedance detection solution is needed.

[0005] The above statements are for the purpose of providing background information in relation to this application only and do not necessarily constitute prior art. Summary of the Invention

[0006] In view of the above problems, this application provides an impedance detection method, device, equipment, medium and product, which can detect the current impedance of the battery based on the current temperature of the battery and the characteristic data of the inflection point of impedance change with temperature during battery use, so as to achieve accurate detection of battery impedance.

[0007] In a first aspect, this application provides an impedance detection method, comprising: acquiring state parameters of a battery, the state parameters including the current temperature of the battery; determining a target impedance characteristic parameter corresponding to the state parameters, the target impedance characteristic parameter including characteristic data at the inflection point of impedance change with temperature; and determining the current impedance of the battery based on the current temperature and the target impedance characteristic parameter.

[0008] In this embodiment, the target impedance characteristic parameter includes characteristic data at the inflection point of impedance change with temperature. By determining the target impedance characteristic parameter corresponding to the state parameter of the battery, and determining the current impedance of the battery based on the target impedance characteristic parameter and the current temperature of the battery, the accuracy of battery impedance detection can be improved, taking into account the fact that battery impedance is greatly affected by temperature and may change significantly at a specific temperature.

[0009] In some embodiments, the state parameters further include the current state of charge (SOC) and the current charge / discharge state; the target impedance characteristic parameters include the target inflection point temperature, the target inflection point impedance, and the target inflection point slope; determining the target impedance characteristic parameters corresponding to the state parameters includes: determining the target inflection point temperature, the target inflection point impedance, and the target inflection point slope corresponding to the current SOC, the current temperature, and the current charge / discharge state based on pre-calibrated electrothermal coupling parameters; wherein, the electrothermal coupling parameters include the inflection point temperature, inflection point impedance, and inflection point slope corresponding to the battery under different SOCs, different temperatures, and different charge / discharge states, respectively, the inflection point temperature and inflection point impedance being the temperature and impedance corresponding to the inflection point of the electrothermal coupling function, and the inflection point slope being the slope at the inflection point in the electrothermal coupling function.

[0010] In this embodiment, the target inflection point temperature, target inflection point impedance, and target inflection point slope corresponding to the current SOC, current temperature, and current charge / discharge state of the battery can be determined based on pre-calibrated electrothermal coupling parameters. This allows for the comprehensive impedance detection of multiple parameters, such as the current temperature, target inflection point temperature, target inflection point impedance, and target inflection point slope of the battery, thereby improving the accuracy of impedance detection.

[0011] In some embodiments, the inflection point slope includes a first slope and a second slope, the electrothermal coupling function includes a first linear function and a second linear function, the intersection of the first linear function and the second linear function is the inflection point, and the first slope and the second slope are the slopes of the first linear function and the second linear function, respectively; determining the target inflection point temperature, target inflection point impedance, and target inflection point slope corresponding to the current SOC, current temperature, and current charge / discharge state based on pre-calibrated electrothermal coupling parameters includes: determining the target inflection point temperature, target inflection point impedance, target first slope, and target second slope corresponding to the current SOC and current charge / discharge state based on the electrothermal coupling parameters; and determining the target inflection point slope from the target first slope and the target second slope based on the current temperature and the target inflection point temperature.

[0012] In this embodiment, since the battery impedance changes significantly at a specific temperature, the electrothermal coupling function will have an inflection point. On both sides of the inflection point, the impedance changes with temperature in different ways, resulting in two slopes. Since the inflection point occurs due to temperature change, the target inflection point slope that better matches the impedance change pattern at the current temperature can be determined from the two slopes based on the current battery temperature and the target inflection point temperature, so as to perform impedance detection more accurately.

[0013] In some embodiments, before acquiring the battery's state parameters, the method further includes: acquiring the battery's current current; and determining the battery's current charge / discharge state based on the current current.

[0014] In this embodiment, the current charge / discharge state of the battery can be determined quickly and accurately based on the current current of the battery.

[0015] In some embodiments, determining the current impedance of the battery based on the current temperature and target impedance characteristic parameters includes: inputting the current temperature and target impedance characteristic parameters into an electrothermal coupling model, performing impedance detection on the battery through the electrothermal coupling model, and outputting the current impedance of the battery.

[0016] In this embodiment, impedance detection can be performed based on the current temperature of the battery and the target impedance characteristic parameters using an electrothermal coupling model, thereby accurately and efficiently determining the current impedance of the battery.

[0017] In some embodiments, the method further includes: obtaining the impedance of the test battery at at least three temperatures for different charge / discharge states and different SOCs; fitting an electrothermal coupling function based on the impedance of each SOC at at least three temperatures for each charge / discharge state to obtain multiple electrothermal coupling functions; and determining the inflection point temperature, inflection point impedance, and inflection point slope of the multiple SOCs for different charge / discharge states based on the multiple electrothermal coupling functions to obtain electrothermal coupling parameters.

[0018] In this embodiment, since the battery impedance changes significantly at a specific temperature, the electrothermal coupling function will have an inflection point. Furthermore, statistical analysis of a large amount of data reveals that the electrothermal coupling function typically has an inflection point. Since two points determine a straight line and two function segments include a common point (i.e., the inflection point), the electrothermal coupling function can be determined using only three points. Therefore, based on test data of the battery at at least three temperatures, the electrothermal coupling function can be fitted, and the electrothermal coupling parameters can be calibrated without requiring extensive testing resources, thus significantly reducing testing costs. Of course, to improve the rationality of the test temperature selection, several temperatures can be appropriately selected to reduce the probability that multiple selected temperatures are all on a straight line, leading to the inability to fit a complete electrothermal coupling function.

[0019] In some embodiments, based on multiple electrothermal coupling functions, the inflection point temperature, inflection point impedance, and inflection point slope corresponding to multiple SOCs under different charge and discharge states are determined to obtain electrothermal coupling parameters. This includes: determining the slopes of the first linear function and the second linear function included in each electrothermal coupling function to obtain the first slope and the second slope; and determining the inflection point temperature and inflection point impedance corresponding to the inflection point of each electrothermal coupling function; and determining the electrothermal coupling parameters based on the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to multiple SOCs under different charge and discharge states.

[0020] In this embodiment, since the battery impedance changes significantly at a specific temperature, the impedance change trends on both sides of the inflection point of each electrothermal coupling function are different. Therefore, by subdividing each electrothermal coupling function into two linear function segments, namely the first linear function and the second linear function, through the inflection point, and determining the slope of the inflection point in the first linear function and the second linear function respectively, the impedance change trend can be reflected more accurately, which can help improve the accuracy of impedance detection.

[0021] In some embodiments, obtaining the impedance of the test battery at different charge / discharge states and different SOCs at at least three temperatures includes: controlling the test battery to discharge from a fully charged state to a fully discharged state while the test battery is at a first temperature, wherein the first temperature is any one of at least three temperatures; obtaining the impedance of the test battery under multiple SOC states during the discharge process to obtain the impedance corresponding to the multiple SOCs of the test battery in the discharge state; controlling the test battery to charge from a fully discharged state to a fully charged state; and obtaining the impedance of the test battery under multiple SOC states during the charging process to obtain the impedance corresponding to the multiple SOCs of the test battery in the charging state.

[0022] In this embodiment of the application, by applying charging pulses and discharging pulses to the test battery at multiple SOCs under at least three temperatures, the impedance of the test battery at different charging and discharging states and different SOCs at at least three temperatures can be quickly and accurately determined.

[0023] In some embodiments, the current impedance of the battery includes the current ohmic impedance and / or electrochemical impedance of the battery.

[0024] In this embodiment, the ohmic impedance and / or electrochemical impedance of the battery can be detected quickly and accurately. The ohmic impedance and electrochemical impedance of the battery can be used to detect battery status data such as battery health status and power status, providing a reliable basis for battery management.

[0025] Secondly, this application provides an impedance detection device, comprising: a first acquisition module for acquiring state parameters of a battery, the state parameters including the current temperature of the battery; a first determination module for determining a target impedance characteristic parameter corresponding to the state parameters, the target impedance characteristic parameter including characteristic data at the inflection point of impedance change with temperature; and a second determination module for determining the current impedance of the battery based on the current temperature and the target impedance characteristic parameter.

[0026] In this embodiment, the target impedance characteristic parameter includes characteristic data at the inflection point of impedance change with temperature. By determining the target impedance characteristic parameter corresponding to the state parameter of the battery, and determining the current impedance of the battery based on the target impedance characteristic parameter and the current temperature of the battery, the accuracy of battery impedance detection can be improved, taking into account the fact that battery impedance is greatly affected by temperature and may change significantly at a specific temperature.

[0027] Thirdly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in the first aspect above.

[0028] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the method described in the first aspect above.

[0029] Fifthly, this application provides a computer program product, including a computer program that is executed by a processor to implement the method described in the first aspect above.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 One of the flowcharts for an impedance detection method provided in some embodiments of this application; Figure 2 A second flowchart illustrating an impedance detection method provided in some embodiments of this application; Figure 3 A flowchart of an impedance detection method provided in some embodiments of this application is shown in part three. Figure 4 A flowchart of an impedance detection method provided in some embodiments of this application is shown in Part 4. Figure 5 Fifth of a flowchart illustrating an impedance detection method provided in some embodiments of this application; Figure 6A flowchart of an impedance detection method provided for some embodiments of this application is shown in Figure 6. Figure 7 Flowchart seven of an impedance detection method provided for some embodiments of this application; Figure 8 This is the eighth flowchart of an impedance detection method provided in some embodiments of this application; Figure 9 A schematic diagram of a first-order equivalent circuit provided for some embodiments of this application; Figure 10 A schematic diagram of discharge pulse test data provided for some embodiments of this application; Figure 11 A schematic diagram of charging pulse test data provided for some embodiments of this application; Figure 12 One of the relationship diagrams provided in some embodiments of this application; Figure 13 A second relational diagram provided for some embodiments of this application; Figure 14 This is a schematic diagram of the structure of an impedance detection device provided in some embodiments of this application; Figure 15 A schematic diagram of the hardware structure of an electronic device provided for some embodiments of this application; Figure 16 This is a schematic diagram of the structure of a storage medium provided for some embodiments of this application.

[0032] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0036] 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 this application. 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.

[0037] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0038] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0039] Battery impedance testing is crucial for achieving precise battery health management and intelligent operation and maintenance. Impedance testing can reveal battery aging trends in advance, identify capacity degradation and safety hazards, optimize charging and discharging strategies, extend battery life, and reduce the risk of thermal runaway. Therefore, an accurate battery impedance testing solution is needed.

[0040] Studies have found that battery impedance is affected by the following factors: the electrolyte is the medium for internal battery transport, and its conductivity decreases significantly with decreasing temperature. When the temperature drops to a certain critical point (such as below 0°C), the viscosity of the electrolyte increases, the ion migration rate slows down significantly, and the internal resistance of the battery increases sharply. The solid electrolyte interphase (SEI) film is a passivation layer covering the surface of the negative electrode and is crucial to battery performance and safety. At low temperatures, the conductivity of the SEI film decreases, and its structure and composition may change, increasing the resistance of ions to passing through the SEI film, thereby increasing battery impedance. Charge transfer impedance is the resistance to ion transfer between the electrode and electrolyte interface. According to Arrhenius law, charge transfer impedance increases exponentially with decreasing temperature. At low temperatures, the charge transfer reaction rate decreases significantly, leading to a significant increase in the proportion of charge transfer impedance in the total impedance. Under low-temperature conditions, the kinetics of ion insertion and extraction decrease, which may lead to the precipitation of metals on the surface of the negative electrode. The deposited metal reacts with the electrolyte to form a new SEI film, further increasing the battery impedance. The structural stability and ion diffusion performance of the positive and negative electrode materials also change at low temperatures. For example, the layered structure of graphite in the negative electrode may shrink at low temperatures, hindering the insertion and extraction of ions, leading to increased impedance. Low temperatures can also cause some side reactions inside the battery, such as the decomposition of the electrolyte and the corrosion of the electrode materials. These side reactions consume active ions and generate high-impedance byproducts, thereby increasing the battery impedance.

[0041] Based on the above research findings, it can be seen that battery impedance is greatly affected by temperature and may change significantly at specific temperatures.

[0042] Therefore, embodiments of this application provide an impedance detection method, apparatus, device, medium, and product. The impedance detection method includes: acquiring state parameters of a battery, including the current temperature of the battery; determining a target impedance characteristic parameter corresponding to the state parameters, including characteristic data at the inflection point of impedance change with temperature; and determining the current impedance of the battery based on the current temperature and the target impedance characteristic parameter.

[0043] In this embodiment, the target impedance characteristic parameter includes characteristic data at the inflection point of impedance change with temperature. By determining the target impedance characteristic parameter corresponding to the state parameter of the battery, and determining the current impedance of the battery based on the target impedance characteristic parameter and the current temperature of the battery, the accuracy of battery impedance detection can be improved, taking into account the fact that battery impedance is greatly affected by temperature and may change significantly at a specific temperature.

[0044] In some embodiments of this application, the battery can be, but is not limited to, a cell, a single battery cell, a battery module, a battery pack, an energy storage cabinet, an energy storage container, etc. The battery can be of any chemical type, such as a lithium-ion battery, a nickel-based battery, a sodium-based battery, a lead-acid battery, etc. Among them, lithium-ion batteries include, but are not limited to, lithium cobalt oxide batteries, lithium manganese oxide batteries, lithium nickel oxide batteries, lithium iron phosphate batteries, etc.

[0045] In some embodiments of this application, the battery can be of any shape and structure, such as a cylindrical battery, a flat battery, a pouch battery, a prismatic battery, etc. The battery can be applied in any application scenario that requires battery use. It can be used as a consumer electronics battery, such as in mobile phones and laptops. The battery can also be used as an energy storage battery, and as a power battery, such as in electric vehicles, electric bicycles, electric aircraft, and electric ships. The impedance detection method provided in some embodiments of this application can perform impedance detection on batteries of any specification, any chemical system, and any usage state.

[0046] The following is combined Figure 1 The impedance detection method provided in the embodiments of this application will be described in detail.

[0047] Figure 1 The diagram shows one of the flowcharts of an impedance detection method provided in one embodiment of this application. It should be noted that the impedance detection method can be applied to an impedance detection device.

[0048] like Figure 1 As shown, the impedance detection method may include the following steps: S110, Obtain battery status parameters; S120, determine the target impedance characteristic parameters corresponding to the state parameters; S130 determines the current impedance of the battery based on the current temperature and target impedance characteristic parameters.

[0049] Among them, the state parameters can be the current state parameters of the battery, which may include the current temperature of the battery.

[0050] Because battery impedance changes significantly at specific temperatures, there is an inflection point in the impedance change with temperature. Target impedance characteristic parameters can include characteristic data at the inflection point of the impedance change with temperature.

[0051] Specifically, the current temperature of the battery can be collected using a temperature sensor.

[0052] Impedance characteristic parameters corresponding to different state parameters can be pre-calibrated, from which the target impedance characteristic parameters corresponding to the current state parameters of the battery can be determined. Since the current state parameters of the battery include the current temperature, the target impedance characteristic parameters determined based on the current state parameters can characterize the characteristic data of the inflection point of the battery's impedance change with temperature in the current state.

[0053] Alternatively, a machine learning model for impedance detection can be pre-built and trained to obtain an impedance detection model. The target impedance characteristic parameters and the current temperature of the battery are input into this impedance detection model to perform impedance detection, and the current impedance of the battery is output.

[0054] In this embodiment, the target impedance characteristic parameter includes characteristic data at the inflection point of impedance change with temperature. By determining the target impedance characteristic parameter corresponding to the state parameter of the battery, and determining the current impedance of the battery based on the target impedance characteristic parameter and the current temperature of the battery, the accuracy of battery impedance detection can be improved, taking into account the fact that battery impedance is greatly affected by temperature and may change significantly at a specific temperature.

[0055] In some embodiments, the state parameters may further include the current state of charge (SOC) and the current charge / discharge state; the target impedance characteristic parameters may include the target inflection point temperature, the target inflection point impedance, and the target inflection point slope; based on this, S120 may include: S121, based on pre-calibrated electrothermal coupling parameters, determines the target inflection point temperature, target inflection point impedance, and target inflection point slope corresponding to the current SOC, current temperature, and current charge / discharge state.

[0056] As can be seen from the above embodiments, the battery's state parameters may include the current temperature, current SOC, and current charge / discharge state.

[0057] The current charging / discharging state can be either charging or discharging.

[0058] Electrothermal coupling parameters can include the inflection point temperature, inflection point impedance, and inflection point slope of the battery at different states of charge (SOC), temperatures, and charge / discharge states. The inflection point temperature and impedance can be the temperature and impedance corresponding to the inflection point of the electrothermal coupling function. The inflection point slope can be the slope at the inflection point of the electrothermal coupling function. The electrothermal coupling function can be a function of impedance changing with temperature. Because battery impedance changes significantly at specific temperatures, there will be an inflection point in the impedance change with temperature.

[0059] For example, the electrothermal coupling parameters can be in tabular form, that is, an electrothermal coupling parameter table.

[0060] Specifically, the inflection point temperature, inflection point impedance, and inflection point slope of the battery under different SOC, temperatures, and charge / discharge states can be pre-calibrated to construct an electrothermal coupling parameter table. Then, based on the current SOC, current temperature, and current charge / discharge state, the corresponding target inflection point temperature, target inflection point impedance, and target inflection point slope can be determined by looking up the electrothermal coupling parameter table, thus obtaining the target impedance characteristic parameters.

[0061] In this embodiment, the target inflection point temperature, target inflection point impedance, and target inflection point slope corresponding to the current SOC, current temperature, and current charge / discharge state of the battery can be determined based on pre-calibrated electrothermal coupling parameters. This allows for the comprehensive impedance detection of multiple parameters, such as the current temperature, target inflection point temperature, target inflection point impedance, and target inflection point slope of the battery, thereby improving the accuracy of impedance detection.

[0062] In some embodiments, the inflection point slope may include a first slope and a second slope, the electrothermal coupling function may include a first linear function and a second linear function, the intersection of the first linear function and the second linear function may be an inflection point, and the first slope and the second slope may be the slopes of the first linear function and the second linear function, respectively; based on this, as Figure 2 As shown, S121 may include: S1211, based on electrothermal coupling parameters, determine the target inflection point temperature, target inflection point impedance, target first slope and target second slope corresponding to the current SOC and current charge / discharge state; S1212, Based on the current temperature and the target inflection point temperature, determine the target inflection point slope from the target first slope and the target second slope.

[0063] The electrothermal coupling function can be a piecewise linear function. The first and second linear functions can be linear functions corresponding to different temperature ranges within the electrothermal coupling function. The first linear function can be the linear function corresponding to the high-temperature range, and the second linear function can be the linear function corresponding to the low-temperature range; that is, the high-temperature and low-temperature ranges are divided by inflection points. Correspondingly, the first slope can be the slope corresponding to the high-temperature range, and the second slope can be the slope corresponding to the low-temperature range.

[0064] Electrothermal coupling parameters may include the inflection point temperature, inflection point impedance, first slope and second slope corresponding to the battery under different SOC and different charge and discharge states.

[0065] For example, the electrothermal coupling parameter table can be shown in Table 1.

[0066] Table 1 - Electrothermal Coupling Parameters

[0067] Specifically, the inflection point temperature, inflection point impedance, first slope, and second slope of the battery under different SOC, temperatures, and charge / discharge states can be pre-calibrated to construct an electrothermal coupling parameter table. Then, based on the current SOC, current temperature, and current charge / discharge state, the corresponding target inflection point temperature, target inflection point impedance, target first slope, and target second slope are determined by referring to the electrothermal coupling parameter table. The target first slope can be the slope corresponding to the high-temperature range, and the target second slope can be the slope corresponding to the low-temperature range.

[0068] Then, the current temperature range of the battery can be determined based on the current temperature of the battery. If the current temperature is higher than the target inflection point temperature, the battery is in the high temperature range, and the first target slope can be determined as the target inflection point slope. If the current temperature is lower than the target inflection point temperature, the battery is in the low temperature range, and the second target slope can be determined as the target inflection point slope. If the current temperature of the battery is equal to the target inflection point temperature, the target inflection point slope can be determined based on the pre-set rules.

[0069] For example, the pre-set rule could be that when the current temperature of the battery is equal to the target inflection point temperature, the target first slope is determined as the target inflection point slope; or when the current temperature of the battery is equal to the target inflection point temperature, the target second slope is determined as the target inflection point slope; or when the current temperature of the battery is equal to the target inflection point temperature, the average of the target first slope and the target second slope is determined as the target inflection point slope.

[0070] In this embodiment, since the battery impedance changes significantly at a specific temperature, the electrothermal coupling function will have an inflection point. On both sides of the inflection point, the impedance changes with temperature in different ways, resulting in two slopes. Since the inflection point occurs due to temperature change, the target inflection point slope that better matches the impedance change pattern at the current temperature can be determined from the two slopes based on the current battery temperature and the target inflection point temperature, so as to perform impedance detection more accurately.

[0071] In some embodiments, such as Figure 3 As shown, prior to S110, the method may further include: S140, Obtain the current current of the battery; S150 determines the current charge / discharge state of the battery based on the current current.

[0072] Specifically, the current charge / discharge state of the battery can be determined based on whether the current current of the battery is positive or negative.

[0073] If the current current of the battery is positive, then the current charge / discharge state of the battery can be determined as the charging state; if the current current of the battery is negative, then the current charge / discharge state of the battery can be determined as the discharging state.

[0074] For example, if the current current of the battery is 10A > 0, then the current charge / discharge state of the battery can be determined to be the charging state; if the current current of the battery is -10A < 0, then the current charge / discharge state of the battery can be determined to be the discharging state.

[0075] In this embodiment, the current charge / discharge state of the battery can be determined quickly and accurately based on the current current of the battery.

[0076] In some embodiments, S130 may include: S131: Input the current temperature and target impedance characteristic parameters into the electrothermal coupling model, perform impedance detection on the battery through the electrothermal coupling model, and output the current impedance of the battery.

[0077] Specifically, an electrothermal coupling model can be pre-constructed, and the electrothermal coupling model can be an electrothermal coupling formula.

[0078] By substituting the current temperature and target impedance characteristic parameters, including the target inflection point temperature, target inflection point impedance, and target inflection point slope, into the electrothermal coupling formula, the current impedance of the battery can be calculated.

[0079] For example, the electrothermal coupling formula can be: ............Formula (1) in, The current temperature. For the battery at the current temperature The current impedance is below. The slope at the target inflection point. The target inflection point temperature, The impedance at the target inflection point.

[0080] It should be noted that the temperatures in the formulas involved in the embodiments of this application are all in Kelvin.

[0081] In this embodiment, impedance detection can be performed based on the current temperature of the battery and the target impedance characteristic parameters using an electrothermal coupling model, thereby accurately and efficiently determining the current impedance of the battery.

[0082] Battery energy storage technology has attracted much attention due to its high efficiency and wide application, and it has great potential in supporting renewable energy and grid stability in the future. In actual operation, energy storage products undergo frequent charging and discharging processes that release heat, and the ambient temperature varies over a very wide range (e.g., -20℃ to 60℃, inclusive). This means that each cell in the energy storage system operates within a wide temperature range. The impedance characteristics of the cells are sensitive to temperature changes, especially at low temperatures where the impedance increases significantly. Temperature changes will indirectly lead to changes in the battery's kinetic characteristics; therefore, battery kinetic models need to consider the coupling relationship between temperature and impedance.

[0083] Traditional kinetic models, when considering the relationship between impedance parameters and temperature, typically use interpolation or simple linear relationships to correct the impedance value at a given temperature. However, these methods have significant problems. Interpolation methods require a large amount of testing time and resources to calibrate the relationship between impedance and temperature, while linear correction methods are only applicable within a narrow temperature range (e.g., 20℃-40℃, inclusive), and the error becomes large beyond this range.

[0084] Currently, there are generally two types of models used to describe battery kinetics: equivalent circuit models and electrochemical models. These two types of models differ significantly in how they consider the effect of temperature on battery impedance coupling. Kinetic models based on equivalent circuit models typically require establishing a comprehensive test matrix to obtain the mapping relationship between temperature and influencing factors such as SOC, SOH, and impedance. Kinetic models based on electrochemical models typically require establishing a three-dimensional thermal model, achieving electrothermal coupling through the interaction between the electrochemical and thermal models.

[0085] In other words, the equivalent circuit model requires a very large test matrix to calibrate the mapping relationship between impedance and temperature under different states of charge (SOC). The electrochemical model, on the other hand, requires a three-dimensional thermal model to detect changes in battery temperature and interactively calculate battery impedance. The three-dimensional thermal model also requires a large number of tests to calibrate various model parameters.

[0086] Therefore, both equivalent circuit models and electrochemical models currently require a large amount of testing resources to calibrate model parameters and mapping relationships, resulting in high testing costs.

[0087] In some embodiments, such as Figure 4 As shown, before S121, the method may further include: S160, obtain the impedance of the test battery at at least three temperatures for different charge / discharge states and different SOCs; S170, based on the impedance fitting of the electrothermal coupling function corresponding to at least three temperatures of each SOC in each charge and discharge state, multiple electrothermal coupling functions are obtained; S180, based on multiple electrothermal coupling functions, determines the inflection point temperature, inflection point impedance and inflection point slope of multiple SOCs under different charge and discharge states, and obtains the electrothermal coupling parameters.

[0088] Specifically, at least three temperatures and multiple SOCs can be preset. When setting the temperature, values ​​can be selected near temperatures where inflection points are likely to occur, based on experience or historical data. For example, inflection points often occur at 10℃ or 25℃, so five temperatures can be set: -20℃, 10℃, 25℃, 45℃, and 60℃. When setting the SOC, multiple SOCs can be selected at certain intervals within the range of 0-100% SOC (inclusive). For example, an arithmetic sequence with a 1% common difference within the range of 0-100% can be selected as multiple SOCs.

[0089] For example, the formula for the electrothermal coupling function can be formula (2), which can be obtained by converting formula (3).

[0090] ............Formula (2) .............Formula (3) in, For battery temperature, The battery temperature is impedance at time, The slope This represents the Kelvin value corresponding to a temperature of 25℃. The battery temperature is The impedance at that time.

[0091] Taking a SOC of 1%, a charge / discharge state as the charging state, and at least three temperatures including -20℃, 10℃, 25℃, 45℃, and 60℃ as examples, the impedances of the battery at these temperatures (-20℃, 10℃, 25℃, 45℃, and 60℃) when in a charging state with a SOC of 1% can be obtained. Based on the temperatures of -20℃, 10℃, 25℃, 45℃, and 60℃ and their corresponding impedances, the electrothermal coupling function is fitted with graphs. The inflection points of these graphs determine the inflection point temperature, inflection point impedance, and inflection point slope, thus obtaining the inflection point temperature, inflection point impedance, and inflection point slope corresponding to the battery in a charging state with a SOC of 1%. The calibration method for the inflection point temperature, inflection point impedance, and inflection point slope corresponding to other SOCs and charge / discharge states is the same as described above. By calibrating the inflection point temperature, inflection point impedance, and inflection point slope corresponding to multiple SOCs under different charge / discharge states using the above process, the electrothermal coupling parameters can be obtained.

[0092] In this embodiment, since the battery impedance changes significantly at a specific temperature, the electrothermal coupling function will have an inflection point. Furthermore, statistical analysis of a large amount of data reveals that the electrothermal coupling function typically has an inflection point. Since two points determine a straight line and two function segments include a common point (i.e., the inflection point), the electrothermal coupling function can be determined using only three points. Therefore, based on test data of the battery at at least three temperatures, the electrothermal coupling function can be fitted, and the electrothermal coupling parameters can be calibrated without requiring extensive testing resources, thus significantly reducing testing costs. Of course, to improve the rationality of the test temperature selection, several temperatures can be appropriately selected to reduce the probability that multiple selected temperatures are all on a straight line, leading to the inability to fit a complete electrothermal coupling function.

[0093] Since the State of Charge (SOC) point for collecting pulse test data may differ during pulse testing, making it difficult to accurately collect pulse test data at a pre-set SOC, in some embodiments, S170 may include: Based on the impedance of each SOC at at least three temperatures under each charge and discharge state in multiple SOCs, the impedance of each standard SOC at at least three temperatures under each charge and discharge state in multiple standard SOCs is determined by linear interpolation. Multiple electrothermal coupling functions are obtained by fitting the impedance of each standard SOC at at least three temperatures under each charge and discharge state.

[0094] The standard SOC can be multiple pre-set different SOCs. For example, an arithmetic sequence with a tolerance of 1% within the range of 0-100% can be selected as multiple standard SOCs.

[0095] In this embodiment, the impedance data corresponding to different SOCs can be accurately standardized and unified by linear interpolation, laying a foundation for subsequent fitting of electrothermal coupling functions.

[0096] In some embodiments, such as Figure 5 As shown, S180 may include: S181, determine the slopes of the first linear function and the second linear function included in each electrothermal coupling function, and obtain the first slope and the second slope; and determine the inflection point temperature and inflection point impedance corresponding to the inflection point of each electrothermal coupling function; S182 determines the electrothermal coupling parameters based on the inflection point temperature, inflection point impedance, first slope and second slope of multiple SOCs under different charge and discharge states.

[0097] The electrothermal coupling function can be a piecewise linear function. Since statistical analysis of extensive data has revealed that the electrothermal coupling function typically has an inflection point, it can comprise two linear functions: a first linear function and a second linear function. The first slope can be the slope of the inflection point on the first linear function, and the second slope can be the slope of the inflection point on the second linear function.

[0098] The inflection point temperature and inflection point impedance can be calculated based on the x and y coordinates of the inflection point.

[0099] For example, the formula for the electrothermal coupling function can be formula (2), then the horizontal axis of the graph of the electrothermal coupling function is ( ), with the vertical axis as Therefore, if the x-coordinate of the inflection point is 0 and the y-coordinate is -8.8, then it can be determined according to... Calculated The specific value, i.e., the inflection point temperature; can be determined based on... Calculated The specific value, i.e., the inflection point impedance. Among them, Known.

[0100] Specifically, for each of the multiple SOCs, the following steps can be performed: determining the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to that SOC in the charging state, and determining the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to that SOC in the discharging state. Performing the above steps for all multiple SOCs yields the electrothermal coupling parameters.

[0101] For example, the process of calibrating the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to multiple SOCs under charging conditions is the same as the process of calibrating the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to multiple SOCs under discharging conditions. Taking the process of calibrating the inflection point temperature, inflection point impedance, first slope, and second slope corresponding to multiple SOCs under charging conditions as an example, as follows... Figure 6 As shown, the calibration process may include S601-S610.

[0102] S601, obtain at least three temperatures of m SOCs in the charging state. The corresponding impedances and at least three temperatures of m SOCs in the discharge state. The corresponding impedances .

[0103] Where m≥2.

[0104] S602, extract at least three temperatures corresponding to the s-th SOC. The corresponding impedances .

[0105] Where s = 1, 2…m.

[0106] S603, based on at least three temperatures corresponding to the s-th SOC. The corresponding impedances ,draw and( The relationship between the two functions is used to obtain the electrothermal coupling function graph.

[0107] S604, determine the inflection point temperature corresponding to the inflection point of the electrothermal coupling function graph. and inflection point impedance .

[0108] S605, determine the slope of the inflection point on the left and right images to obtain the first slope and the second slope.

[0109] S606, determine if s is equal to m.

[0110] If yes, then end; otherwise, execute S607.

[0111] Normally, s will not be greater than m, so "no" can mean that s is less than m.

[0112] S607, s=s+1, and return to execute S602.

[0113] In this embodiment, since the battery impedance changes significantly at a specific temperature, the impedance change trends on both sides of the inflection point of each electrothermal coupling function are different. Therefore, by subdividing each electrothermal coupling function into two linear function segments, namely the first linear function and the second linear function, through the inflection point, and determining the slope of the inflection point in the first linear function and the second linear function respectively, the impedance change trend can be reflected more accurately, which can help improve the accuracy of impedance detection.

[0114] In some embodiments, such as Figure 7 As shown, S160 may include: S161, when the test battery is at the first temperature, control the test battery to discharge from the fully charged state to the fully discharged state; S162, obtain the impedance of the test battery under multiple SOC conditions during the discharge process, and obtain the impedance corresponding to the multiple SOCs of the test battery in the discharge state. S163 controls the test battery to charge from a fully discharged state to a fully charged state; S164, obtain the impedance of the test battery under multiple SOC conditions during the charging process, and obtain the impedance corresponding to the multiple SOCs of the test battery under the charging state.

[0115] The test battery can be the same battery used to obtain test data during the calibration of electrothermal coupling parameters, and the test battery can be the same model as the battery that needs to be impedance tested.

[0116] The first temperature can be any of at least three temperatures. For example, the test battery can be placed in a temperature chamber, and the battery temperature can be changed by adjusting the chamber temperature. To ensure the battery temperature reaches the chamber's set temperature, the battery can be left to stand in the chamber for a certain period of time after each temperature adjustment before testing; for example, it can be left to stand for 2 hours.

[0117] A fully charged state can refer to the battery being charged to the upper limit of the cutoff voltage and cutoff current, while a fully discharged state can refer to the battery being discharged to the lower limit of the cutoff voltage.

[0118] Specifically, pulse tests can be performed on the test battery at any temperature to obtain pulse test data. Based on the pulse test data, the impedance of the test battery at at least three temperatures and for different states of charge / discharge and different states of charge (SOC) can be determined. The pulse test data can include the voltage and current of the test battery, and the impedance can be calculated based on the voltage and current using a least-squares fitting algorithm.

[0119] For example, such as Figure 8 As shown, the pulse test procedure may include: S801, adjust the temperature of the electrical box to the i-th temperature among q temperatures, i=1, 2…q (q≥3).

[0120] S802, place the battery in the battery box and let it stand for 2 hours.

[0121] S803, charge the battery to full charge.

[0122] S804 applies a discharge pulse to the j-th SOC among m SOCs and then allows it to rest, where j = 1, 2…m (m ≥ 2). Here, the m SOCs are arranged in descending order.

[0123] S805 collects pulse test data of the test battery at the j-th SOC at the i-th temperature.

[0124] S806, determine if j is equal to m.

[0125] If yes, then execute S808; otherwise, execute S807.

[0126] Normally, j will not be greater than m, so "no" can mean that j is less than m.

[0127] S807, j=j+1, and return to execute S804.

[0128] S808 discharges the battery to a fully discharged state.

[0129] S809 applies a charging pulse to the p-th SOC among m SOCs and then allows it to rest, where p = 1, 2…m (m ≥ 2). Here, the m SOCs are arranged in ascending order.

[0130] S810 collects pulse test data of the test battery at the p-th SOC at the i-th temperature.

[0131] S811, determine whether p is equal to m.

[0132] If yes, then execute S813; otherwise, execute S812.

[0133] Normally, p will not be greater than m, so "no" can mean that p is less than m.

[0134] S812, p=p+1, and return to execute S809.

[0135] S813, determine whether i is equal to q.

[0136] If yes, then end; otherwise, execute S814.

[0137] Normally, i will not be greater than q, so "no" can mean i is less than q.

[0138] S814, i = i + 1, and return to execute S801.

[0139] In this embodiment of the application, by applying charging pulses and discharging pulses to the test battery at multiple SOCs under at least three temperatures, the impedance of the test battery at different charging and discharging states and different SOCs at at least three temperatures can be quickly and accurately determined.

[0140] In some embodiments, the current impedance of the battery may include the battery’s current ohmic impedance and / or electrochemical impedance.

[0141] The ohmic impedance of a battery can be considered as the instantaneous linear resistance generated by the current flow at the moment of energization, independent of the electrochemical reaction, and is determined by purely resistive components such as electrodes, electrolyte, separator, current collector, and contact resistance. The electrochemical impedance of a battery can refer to the frequency-dependent complex impedance directly related to electrochemical processes such as charge transfer at the electrode / electrolyte interface, double-layer capacitance, and diffusion of active species under AC excitation.

[0142] The current ohmic impedance and electrochemical impedance of the battery can be detected using the above-described embodiments.

[0143] In this embodiment, the ohmic impedance and / or electrochemical impedance of the battery can be detected quickly and accurately. The ohmic impedance and electrochemical impedance of the battery can be used to detect battery status data such as the State of Health (SOH) and State of Power (SOP), providing a reliable basis for battery management.

[0144] The embodiments of this application can be applied to modeling conventional n-order equivalent circuit models, where n is a positive integer. The number of resistor-capacitor (RC) networks can be selected according to the requirements of computational speed and accuracy. Unlike conventional equivalent circuit models, the embodiments of this application consider the relationship between model parameters and different operating states. To better describe the entire scheme, a specific example is given below based on the above embodiments.

[0145] The specific process of the impedance detection method provided in this application embodiment can be as follows: 1. Apply the following pulse test to the test battery sequentially at ambient temperatures of -20℃, 10℃, 25℃, 45℃, and 60℃ (taking 25℃ as an example), and obtain the pulse test data: (1) At 25°C, the test battery is charged at a constant current of 0.04C to a voltage of 3.65V and left to stand for 5 minutes.

[0146] (2) Discharge at a constant current of 0.5C for 60 seconds.

[0147] (3) Collect pulse test data after standing for 5 minutes.

[0148] (4) Repeat steps (2)-(3) until the voltage is lower than or equal to 2.5V.

[0149] (5) Discharge at a constant current rate of 0.04C until the voltage is lower than or equal to 2.5V.

[0150] (6) Charge at a constant current of 0.5C for 60 seconds.

[0151] (7) Collect pulse test data after standing for 5 minutes.

[0152] (8) Repeat steps (6)-(7) until the voltage is equal to or greater than 3.65V.

[0153] 2. Taking a first-order equivalent circuit model as an example, pulse test data is used to identify the parameters of the model and obtain the pulse test data.

[0154] The first-order equivalent circuit model can be as follows Figure 9 As shown, where, For ohmic impedance, This represents electrochemical impedance.

[0155] Taking a specific state of charge (SOC) as an example, the discharge pulse test data at that SOC can be as follows: Figure 10 As shown, the charging pulse test data can be obtained as follows: Figure 11 As shown. Impedance parameters can be determined using a least-squares fitting algorithm based on pulse test data, thus allowing the construction of the aforementioned temperature, SOC, charge / discharge state, and... and The mapping table is shown in Table 2.

[0156] Table 2 - Mapping Table

[0157] in, Impedance in the charging state ; Impedance in the discharge state ; Impedance in the charging state ; Impedance in the discharge state .

[0158] 3. Construct an electrothermal coupling parameter table (1) Extract the SOC and impedance at each temperature and under each charge / discharge state, for example, at -20°C. SOC- can be extracted The corresponding table is shown in Table 3.

[0159] Table 3 - Correspondence Table

[0160] (2) Using linear interpolation, convert the correspondence table into a standard SOC- The standard correspondence table, taking standard SOC=0.01 as an example, shows the corresponding values ​​after conversion. The value is: The standard SOC obtained after conversion at -20℃ The standard correspondence table is shown in Table 4.

[0161] Table 4 - Standard Correspondence Table

[0162] Other temperatures and other impedance parameters are processed in the same way to obtain the standard SOC-impedance parameter table, with 5 temperatures (-20℃, 10℃, 25℃, 45℃, 60℃) and 4 impedance parameters ( , , , There are 20 tables in total.

[0163] Then, impedance parameters at different temperatures corresponding to each standard SOC are plotted. Starting with SOC=0, For example, plot the impedance parameters and temperature Relationship diagrams can be like... Figure 12 As shown. Convert to and Relationship diagrams can be like... Figure 13 As shown.

[0164] Observing the shape of the image, we can see that the inflection point is at 25℃. Record the temperature of the inflection point as 25℃. That is, less than 25℃ is low temperature, and more than 25℃ is high temperature.

[0165] By performing linear fitting on both sides of the inflection point, we can obtain the slope of the low temperature region (i.e., the second slope) k1 = 8528 and the slope of the high temperature region (i.e., the first slope) k2 = 789.

[0166] In summary, a single SOC point Inflection point temperature can be obtained Inflection point impedance The four values ​​are: the slope k1 in the low-temperature region, the slope k2 in the high-temperature region, and so on.

[0167] Other SOC points and other impedance parameters are processed in the same way, and the final electrothermal coupling parameter table shown in Table 5 can be obtained.

[0168] Table 5 - Electrothermal Coupling Parameters

[0169] 4. Impedance detection by For example: The battery's current temperature, current SOC, and current current are all external inputs to the electrothermal coupling model. Assume the battery's current temperature T = 45℃, current SOC = 0, and current current I = 10A. First, based on SOC = 0, the inflection point temperature is determined by looking up the electrothermal coupling parameter table. =25℃, based on the current temperature T=45℃, it can be determined that the battery is in the high-temperature zone; based on the current I=10A>0, it can be determined that the battery is in the charging state; based on the three conditions of SOC=0, high-temperature zone, and charging state, the electrothermal coupling parameter table can be consulted to obtain the target inflection point slope k=789. =0.0002Ω. Finally, T=45+273.15=318.15K, k=789, =0.0002Ω =25 + 273.15 = 298.15K Substitute into the formula The battery impedance can be calculated when T=45℃, SOC=0, and current I=10A. =0.0001Ω.

[0170] While battery dynamics models based on equivalent circuit models offer higher computational efficiency, they still require significant testing resources and time to obtain the impedance-temperature mapping relationship, resulting in high testing costs. Therefore, this application proposes a novel electrothermal coupling model and corresponding testing method for battery dynamics models based on equivalent circuit models. This reduces the testing costs required for modeling the electrothermal coupling relationship without increasing the complexity of the dynamics model. By performing charge-discharge pulse tests at three temperatures, the impedance-temperature mapping relationship can be obtained at any temperature and SOC within a wide temperature threshold (e.g., -20℃ to 60℃, inclusive), thus significantly reducing testing costs.

[0171] In the impedance detection method provided in this application embodiment, pulse test data is obtained by performing pulse tests at at least three temperatures, and then the electrothermal coupling parameters are calibrated. The test time is short, the test cost is low, the data analysis is simple and efficient, and the equipment cost is also relatively low.

[0172] Based on the same inventive concept, this application also provides an impedance detection device. The following describes... Figure 14 The impedance detection device provided in the embodiments of this application will be described in detail.

[0173] Figure 14 A schematic diagram of an impedance detection device provided in one embodiment of this application is shown.

[0174] like Figure 14 As shown, the impedance detection device may include: The first acquisition module 1401 is used to acquire the status parameters of the battery, including the current temperature of the battery. The first determining module 1402 is used to determine the target impedance characteristic parameters corresponding to the state parameters. The target impedance characteristic parameters include characteristic data at the inflection point of impedance change with temperature. The second determining module 1403 is used to determine the current impedance of the battery based on the current temperature and the target impedance characteristic parameters.

[0175] In this embodiment, the target impedance characteristic parameter includes characteristic data at the inflection point of impedance change with temperature. By determining the target impedance characteristic parameter corresponding to the battery's state parameters, and determining the battery's current impedance based on the target impedance characteristic parameter and the battery's current temperature, the battery's current impedance can be comprehensively detected based on the battery's current temperature and the characteristic data at the inflection point of impedance change with temperature, thereby improving the accuracy of battery impedance detection.

[0176] In some embodiments, the state parameters further include the current state of charge (SOC) and the current charge / discharge state; the target impedance characteristic parameters include the target inflection point temperature, the target inflection point impedance, and the target inflection point slope; the first determining module 1402 may include: The first determination submodule is used to determine the target inflection point temperature, target inflection point impedance and target inflection point slope corresponding to the current SOC, current temperature and current charge / discharge state based on pre-calibrated electrothermal coupling parameters. Among them, the electrothermal coupling parameters include the inflection point temperature, inflection point impedance, and inflection point slope corresponding to the battery under different SOC, different temperatures, and different charge and discharge states. The inflection point temperature and inflection point impedance are the temperature and impedance corresponding to the inflection point of the electrothermal coupling function, and the inflection point slope is the slope at the inflection point in the electrothermal coupling function.

[0177] In some embodiments, the inflection point slope includes a first slope and a second slope, the electrothermal coupling function includes a first linear function and a second linear function, the intersection of the first linear function and the second linear function is the inflection point, and the first slope and the second slope are the slopes of the first linear function and the second linear function, respectively; the first determining submodule may include: The first determining unit is used to determine, based on the electrothermal coupling parameters, the target inflection point temperature, the target inflection point impedance, the target first slope, and the target second slope corresponding to the current SOC and the current charge / discharge state. The second determining unit is used to determine the target inflection point slope from the target first slope and the target second slope based on the current temperature and the target inflection point temperature.

[0178] In some embodiments, the impedance detection device may further include: The second acquisition module is used to acquire the current current of the battery; The third determining module is used to determine the current charge / discharge state of the battery based on the current current.

[0179] In some embodiments, the second determining module 1403 may include: The model detection submodule is used to input the current temperature and target impedance characteristic parameters into the electrothermal coupling model, perform impedance detection on the battery through the electrothermal coupling model, and output the current impedance of the battery.

[0180] In some embodiments, the impedance detection device may further include: The third acquisition module is used to acquire the impedance of the test battery at at least three temperatures, under different charge / discharge states and different SOCs. The fitting module is used to fit the electrothermal coupling function based on the impedance corresponding to at least three temperatures of each SOC in each charge and discharge state, to obtain multiple electrothermal coupling functions. The fourth determination module is used to determine the inflection point temperature, inflection point impedance, and inflection point slope of multiple SOCs under different charge and discharge states based on multiple electrothermal coupling functions, thereby obtaining electrothermal coupling parameters.

[0181] In some embodiments, the fourth determining module may include: The second determining submodule is used to determine the slopes of the first linear function and the second linear function included in each electrothermal coupling function, to obtain the first slope and the second slope; and to determine the inflection point temperature and inflection point impedance corresponding to the inflection point of each electrothermal coupling function. The third determination submodule is used to determine the electrothermal coupling parameters based on the inflection point temperature, inflection point impedance, first slope and second slope of multiple SOCs under different charge and discharge states.

[0182] In some embodiments, the third acquisition module may include: The first control submodule is used to control the test battery to discharge from a fully charged state to a fully discharged state when the test battery is at a first temperature, wherein the first temperature is any one of at least three temperatures. The first acquisition submodule is used to acquire the impedance of the test battery under multiple SOC conditions during the discharge process, and obtain the impedance corresponding to the multiple SOCs of the test battery in the discharge state. The second control submodule is used to control the test battery to charge from a fully discharged state to a fully charged state. The second acquisition submodule is used to acquire the impedance of the test battery under multiple SOC conditions during the charging process, and obtain the impedance corresponding to the multiple SOCs of the test battery under the charging state.

[0183] In some embodiments, the current impedance of the battery includes the current ohmic impedance and / or electrochemical impedance of the battery.

[0184] The impedance detection device and the impedance detection method provided in this application are based on the same inventive concept and have the same beneficial effects as the methods they employ, operate, or implement.

[0185] The specific implementation process of the functions and roles of each module in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0186] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components illustrated as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0187] Some embodiments of this application also provide an electronic device corresponding to the impedance detection method provided in the foregoing embodiments, for performing the impedance detection method described above.

[0188] Figure 15 The present invention illustrates a hardware structure diagram of an electronic device according to an exemplary embodiment. The electronic device includes a communication interface 1501, a processor 1502, a memory 1503, and a bus 1504. The communication interface 1501, processor 1502, and memory 1503 communicate with each other via the bus 1504. The processor 1502 can execute the impedance detection method described above by reading and executing machine-executable instructions corresponding to the control logic of the impedance detection method stored in the memory 1503. The specific details of this method are described in the above embodiment and will not be repeated here.

[0189] The memory 1503 mentioned in this embodiment can be any electronic, magnetic, optical, or other physical storage device, and can contain stored information such as executable instructions, data, etc. Specifically, the memory 1503 can be RAM (Random Access Memory), flash memory, storage drive (such as hard disk drive), any type of storage disk (such as optical disc, DVD, etc.), or similar storage media, or combinations thereof. Communication between this system network element and at least one other network element is achieved through at least one communication interface 1501 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc., can be used.

[0190] Bus 1504 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. Memory 1503 is used to store programs, and processor 1502 executes the programs after receiving execution instructions.

[0191] Processor 1502 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 1502 or by instructions in software form. The processor 1502 can be a general-purpose processor, including a network processor (NP), digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware controls, etc. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor.

[0192] The electronic device provided in this application embodiment and the impedance detection method provided in this application embodiment are based on the same inventive concept and have the same beneficial effects as the methods they adopt, operate or implement.

[0193] This application also provides a computer-readable storage medium corresponding to the impedance detection method provided in the foregoing embodiments. Please refer to... Figure 16 As shown, the computer-readable storage medium is an optical disc 160, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it executes the impedance detection method provided in any of the foregoing embodiments.

[0194] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical and magnetic storage media, which will not be elaborated here.

[0195] The computer-readable storage medium provided in the above embodiments of this application and the impedance detection method provided in the embodiments of this application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0196] This application also provides a computer program product corresponding to the impedance detection method provided in the foregoing embodiments. The computer program product includes a computer program that is executed by a processor to implement the impedance detection method provided in the foregoing embodiments.

[0197] The computer program products provided in the above embodiments of this application and the impedance detection methods provided in the embodiments of this application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0198] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0199] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An impedance detection method, characterized in that, include: Obtain the battery's status parameters, including the battery's current temperature; Determine the target impedance characteristic parameters corresponding to the state parameters, wherein the target impedance characteristic parameters include characteristic data at the inflection point of impedance change with temperature; The current impedance of the battery is determined based on the current temperature and the target impedance characteristic parameters.

2. The method according to claim 1, characterized in that, The state parameters also include the current state of charge (SOC) and the current charge / discharge state; the target impedance characteristic parameters include the target inflection point temperature, the target inflection point impedance, and the target inflection point slope. Determining the target impedance characteristic parameters corresponding to the state parameters includes: Based on pre-calibrated electrothermal coupling parameters, the target inflection point temperature, the target inflection point impedance, and the target inflection point slope corresponding to the current SOC, the current temperature, and the current charge / discharge state are determined. The electrothermal coupling parameters include the inflection point temperature, inflection point impedance, and inflection point slope corresponding to the battery under different SOC, different temperatures, and different charge / discharge states. The inflection point temperature and the inflection point impedance are the temperature and impedance corresponding to the inflection point of the electrothermal coupling function, and the inflection point slope is the slope at the inflection point in the electrothermal coupling function.

3. The method according to claim 2, characterized in that, The inflection point slope includes a first slope and a second slope, the electrothermal coupling function includes a first linear function and a second linear function, the intersection of the first linear function and the second linear function is the inflection point, and the first slope and the second slope are the slopes of the first linear function and the second linear function, respectively; The determination of the target inflection point temperature, the target inflection point impedance, and the target inflection point slope, based on pre-calibrated electrothermal coupling parameters and corresponding to the current SOC, the current temperature, and the current charge / discharge state, includes: Based on the electrothermal coupling parameters, the target inflection point temperature, the target inflection point impedance, the target first slope, and the target second slope corresponding to the current SOC and the current charge / discharge state are determined; Based on the current temperature and the target inflection point temperature, the target inflection point slope is determined from the target first slope and the target second slope.

4. The method according to claim 2, characterized in that, Before acquiring the battery's state parameters, the method further includes: Obtain the current current of the battery; The current charge / discharge state of the battery is determined based on the current current.

5. The method according to any one of claims 1-4, characterized in that, Determining the current impedance of the battery based on the current temperature and the target impedance characteristic parameters includes: The current temperature and the target impedance characteristic parameters are input into the electrothermal coupling model, and the impedance of the battery is detected by the electrothermal coupling model to obtain the current impedance of the battery.

6. The method according to claim 3, characterized in that, The method further includes: Obtain the impedance of the test battery at at least three temperatures, for different states of charge and discharge, and for different states of charge (SOC). Multiple electrothermal coupling functions are obtained by fitting an impedance to an electrothermal coupling function corresponding to at least three temperatures of each of the multiple SOCs under each of the charge and discharge states. Based on the multiple electrothermal coupling functions, the inflection point temperature, inflection point impedance, and inflection point slope of the multiple SOCs under different charge and discharge states are determined, and the electrothermal coupling parameters are obtained.

7. The method according to claim 6, characterized in that, The electrothermal coupling parameters are obtained by determining the inflection point temperature, inflection point impedance, and inflection point slope of the multiple SOCs under different charge and discharge states based on multiple electrothermal coupling functions, including: The slopes of the first linear function and the second linear function included in each electrothermal coupling function are determined respectively to obtain the first slope and the second slope; and the inflection point temperature and inflection point impedance corresponding to the inflection point of each electrothermal coupling function are determined. The electrothermal coupling parameters are determined based on the inflection point temperature, inflection point impedance, first slope, and second slope of the multiple SOCs under different charge and discharge states.

8. The method according to claim 6, characterized in that, The acquisition of the impedance of the test battery at at least three temperatures, under different charge / discharge states and different states of charge (SOC), includes: When the test battery is at a first temperature, the test battery is controlled to discharge from a fully charged state to a fully discharged state, where the first temperature is any one of the at least three temperatures. The impedance of the test battery under multiple SOC conditions during the discharge process is obtained, thus obtaining the impedance corresponding to each SOC of the test battery in the discharge state. Control the test battery to charge from a fully discharged state to a fully charged state; The impedance of the test battery under multiple SOC conditions during the charging process is obtained, thus obtaining the impedance corresponding to each SOC of the test battery under the charging state.

9. The method according to claim 1, characterized in that, The current impedance of the battery includes the current ohmic impedance and / or electrochemical impedance of the battery.

10. An impedance detection device, characterized in that, include: The first acquisition module is used to acquire the status parameters of the battery, including the current temperature of the battery; The first determining module is used to determine the target impedance characteristic parameters corresponding to the state parameters, wherein the target impedance characteristic parameters include characteristic data at the inflection point of impedance change with temperature. The second determining module is used to determine the current impedance of the battery based on the current temperature and the target impedance characteristic parameters.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the program to implement the method as described in any one of claims 1-9.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by a processor to implement the method as described in any one of claims 1-9.

13. A computer program product, comprising a computer program, characterized in that, The computer program is executed by a processor to implement the method according to any one of claims 1-9.

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