Method of determining the resistance of a battery cell and electronic device performing the method

Abstract

A method and electronic device for determining the resistance of a battery cell are disclosed. The method includes the steps of: performing an EIS analysis of the battery cell based on a plurality of temperatures including a first temperature and a second temperature to obtain a graph relating the impedance of the battery cell to a frequency variation; extracting a first inductance of the battery cell at the first temperature based on a first graph relating the impedance of the battery cell at the first temperature; and determining the resistance of the battery cell at a second temperature based on the first inductance, wherein the second temperature is higher than the first temperature.

Description

Technical Field

[0001] This disclosure relates to a method for determining the resistance of a single battery cell and an electronic device for performing the method. Background Technology

[0002] Pouch-type stacked cells correspond to the type of batteries installed in most electric vehicles. The resistive components of pouch-type stacked cells, such as the ohmic resistance of the cell, vary due to the electrical characteristics of the foils and electrodes based on the design. Since the various resistive components affect the battery output during the operation of an electric vehicle, it is necessary to determine the resistive components of the cell and conduct additional analysis based on the corresponding resistive components in order to improve battery performance.

[0003] Impedance measurement methods using electrochemical impedance spectroscopy (EIS) are primarily used to determine the resistive components of individual battery cells. Furthermore, various studies are currently underway to determine methods for achieving resistances suitable for different types of battery cells. Summary of the Invention

[0004] Technical goals

[0005] Example embodiments of this disclosure provide a method for determining the resistance of a single battery cell and an electronic device for performing the method.

[0006] The exemplary embodiments of this disclosure are for accurately measuring various types of resistance of battery cells, taking into account the electrical characteristics of batteries that vary based on battery designs such as pouch-type stacked cells.

[0007] However, the objectives to be achieved by the exemplary embodiments of this disclosure are not limited to the above objectives, and other objectives can be clearly understood from the following exemplary embodiments.

[0008] Technical solution

[0009] According to one aspect, a method for determining the resistance of a battery cell is provided, the method comprising: obtaining a graph of the battery cell's impedance based on frequency variations by performing electrochemical impedance spectroscopy (EIS) analysis on the battery cell based on a plurality of temperatures including a first temperature and a second temperature; extracting a first inductance of the battery cell at the first temperature based on a first curve of the battery cell's impedance at the first temperature included in the graph; and determining the resistance of the battery cell at a second temperature based on the first inductance, wherein the second temperature is a temperature higher than the first temperature.

[0010] Determining the resistance of a battery cell at the second temperature may include: determining the first inductance as the second inductance of the battery cell at the second temperature.

[0011] Determining the resistance of a battery cell at a second temperature may include: determining the ohmic resistance of the battery cell at a second temperature based on the value obtained by subtracting the second inductance from the intercept value of the real impedance axis of a second graph of the battery cell's impedance at the second temperature; and determining the charge transfer resistance of the battery cell at the second temperature as the difference between the resistance at the inflection point of the second graph and the ohmic resistance of the battery cell at the second temperature.

[0012] Determining the ohmic resistance of a battery cell at a second temperature may include: obtaining a reference ohmic resistance at the second temperature based on the relationship between the second temperature and the ohmic resistance of the battery cell at the second temperature; and when the difference between the reference ohmic resistance and the ohmic resistance of the battery cell at the second temperature is less than a threshold, determining the ohmic resistance of the battery cell at the second temperature based on a value obtained by subtracting a second inductance from the intercept value of the real impedance axis of a second graph of the impedance of the battery cell at the second temperature.

[0013] The method may further include: applying a pulse current to a battery cell at a second temperature for a predefined time, and obtaining a final total resistance based on the change in the total resistance of the battery cell at the second temperature according to the application of the pulse current.

[0014] Obtaining the final total resistance at the second temperature may include: obtaining the final total resistance at the second temperature based on the sum of the ohmic resistance of the battery cell at the second temperature, the charge transfer resistance of the battery cell at the second temperature, and the mass transfer resistance of the battery cell at the second temperature.

[0015] A single battery cell can be a pouch-type stacked cell having a positive electrode comprising active materials, conductive materials, and a binder, and a negative electrode comprising graphite, conductive materials, and a binder, which are stacked together.

[0016] The second temperature can be the normal temperature, and the first temperature can be a sub-zero temperature.

[0017] According to another aspect, an electronic device is also provided, comprising: a memory configured to store instructions; and a processor connected to the memory, the processor being configured to obtain a graph of the impedance of a battery cell based on frequency variation by performing electrochemical impedance spectroscopy (EIS) analysis on a battery cell based on a plurality of temperatures including a first temperature and a second temperature, extracting a first inductance from a first curve of the impedance of the battery cell at the first temperature included in the battery cell graph, and determining the resistance of the battery cell at a second temperature based on the first inductance, wherein the second temperature is a temperature higher than the first temperature.

[0018] Effects of the present invention

[0019] Based on the example embodiments, one or more of the following effects can be expected.

[0020] According to the example embodiment, even though it is difficult to visually identify the ohmic resistance and charge transfer resistance of a battery cell at a predetermined temperature on a graph of the battery cell impedance due to the inductive component generated during the battery design process by electrochemical impedance spectroscopy (EIS) analysis, electronic devices can determine the ohmic resistance and charge transfer resistance of a battery cell by using the characteristics of inductance.

[0021] Furthermore, according to the example embodiment, the electronic device can verify the accuracy of the ohmic resistance of a battery cell determined based on a graph of the battery cell's impedance and inductance, and can determine additional resistance components, such as the battery cell's mass transfer resistance.

[0022] Based on the following description of the appended claims, the effects of this disclosure are not limited to those described above, and other effects may be apparent to those skilled in the art. Attached Figure Description

[0023] Figure 1 This is a diagram illustrating the configuration of a system for determining the resistance of a single battery cell according to an example embodiment.

[0024] Figure 2 This is a diagram used to describe the electrochemical impedance spectroscopy (EIS) analysis method according to an example embodiment.

[0025] Figure 3 This is a graph, according to an example embodiment, used to describe impedance information in which electrochemical impedance spectroscopy (EIS) analysis is performed on a target battery cell at each temperature.

[0026] Figure 4 This is a diagram illustrating the inductance of a battery cell according to an example embodiment, based on the temperature variation of the battery cell.

[0027] Figure 5 This is a flowchart describing a method for determining the resistance of a single battery cell according to an example embodiment.

[0028] Figure 6 This is a diagram illustrating the process of obtaining the ohmic resistance of a single battery cell according to an example embodiment.

[0029] Figure 7 This is a diagram illustrating the process of obtaining the mass transfer resistance and total resistance of a single battery cell according to an example embodiment.

[0030] Figure 8 This is a block diagram illustrating an electronic device according to an example embodiment. Detailed Implementation

[0031] The terminology used in the example embodiments has been selected as much as possible from currently widely used general terms, while taking into account the functionality obtained according to this disclosure. However, these terms may be replaced by other terms based on the intent of those skilled in the art, convention, the emergence of new technologies, etc. Furthermore, in certain cases, terms arbitrarily chosen by the applicant of this disclosure may be used. In such cases, the meaning of these terms may be described in the corresponding descriptive section of this disclosure. Therefore, it should be noted that the terms used herein should be interpreted based on their actual meaning and the entirety of this specification, rather than simply on their names.

[0032] Throughout the specification, when an element is referred to as "including" another element, that element should not be construed as excluding other elements, provided there is no specific conflicting description, and that element may include at least one other element.

[0033] Throughout the specification, the phrase "at least one of a, b, and c" may include "only a", "only b", "only c", "a and b", "a and c", "b and c", or "all of a, b, and c".

[0034] In this disclosure, "device" can be implemented as a computer or portable device capable of accessing a server or another device via a network. A computer can include, for example, a laptop computer, a desktop computer, and a notebook equipped with a web browser. A portable device can be a wireless communication device that ensures portability and mobility, and includes any type of handheld wireless communication device, such as a tablet PC, a smartphone, or a device based on communications such as International Mobile Telecommunications (IMT), Code Division Multiple Access (CDMA), W-CDMA, and Long Term Evolution (LTE).

[0035] In the following description, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily practice the present disclosure. However, the present disclosure may be implemented in many different forms and is not limited to the exemplary embodiments described herein.

[0036] In the following description, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0037] Figure 1 This is a diagram illustrating the configuration of a system for determining the resistance of a single battery cell according to an example embodiment.

[0038] refer to Figure 1The system 101 can operate in conjunction with an electronic device 100 that measures the resistance of a battery cell 200. In this case, the battery cell 200 can be a pouch-type stacked cell, having a structure in which a positive electrode comprising active material, conductive material, and binder is stacked with a negative electrode comprising graphite, conductive material, and binder. Alternatively, the battery cell 200 can be a pouch-type cell, a cylindrical cell, or a prismatic cell. Meanwhile, specific elements associated with this example embodiment... Figure 1 The illustration is shown in the figure. Therefore, those skilled in the art associated with this example embodiment will understand that, in addition to Figure 1 In addition to the components shown in the diagram, other commonly used components may be included.

[0039] Electronic device 100 may include one or more sensors for measuring parameters of the conductance of the aforementioned battery cell 200, which is determined as a resistance, and may include a memory and processor (not shown) for various operations. In other words, electronic device 100 can perform the operation of obtaining a graph of the impedance of battery cell 200 based on frequency changes by performing electrochemical impedance spectroscopy (EIS) analysis on battery cell 200 based on multiple temperatures. In this case, the graph of the impedance of battery cell 200 may correspond to, for example, a Nyquist graph.

[0040] According to an example embodiment, battery cell 200 may correspond to a battery cell impregnated with an electrolyte, comprising a positive electrode including active material, binder, and conductive material, and a negative electrode including graphite, binder, and conductive material. For example, battery cell 200 may correspond to a pouch-type stacked cell having a structure in which a positive electrode including active material, conductive material, and binder and a negative electrode including graphite, conductive material, and binder are stacked. Specifically, battery cell 200 may correspond to a pouch-type cell having a form in which 19 positive / negative electrode cells having a width of approximately 90 mm and a length of 258 mm are stacked.

[0041] For example, the mass of the active material, binder, and conductive material can account for 97.5%, 1.5%, and 1% of the total mass of the active material layer including the active material, binder, and conductive material, respectively. Therefore, the positive electrode can correspond to a positive electrode where the conductive material content is 1% of the entire active material layer of the electrode. For example, the mass of graphite, binder, and conductive material can account for 95%, 3.5%, and 1.5% of the total mass of graphite, binder, and conductive material, respectively. Therefore, the negative electrode can correspond to a target negative electrode where the conductive material content is 1.5% of the entire active material layer of the target electrode. For example, the battery cell 200 can be impregnated with an electrolyte in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a ratio of 3 to 7, and one mole of lithium hexafluorophosphate (LiPF6) is added. However, the type of battery cell 200 in the method for determining the resistance of the battery cell 200 according to this disclosure is not limited to the above-described cases. Example embodiments of this disclosure may include battery cells 200 in various forms, such as cylindrical cells, prismatic cells, and pouch-type stacked cells, and may include various types of positive and negative electrodes and various types of electrolytes.

[0042] Figure 2 This is a diagram used to describe the electrochemical impedance spectroscopy (EIS) analysis method according to an example embodiment.

[0043] refer to Figure 2 The concept of EIS used to determine the resistance of a battery cell can be identified. Impedance spectrum can be a method of interpreting Nyquist plot 201, which is obtained by dividing impedance information obtained by continuously varying the frequency 210 of an alternating current (AC) power supply and applying frequency 210 to the battery cell 200 by real impedance 220 and imaginary impedance 230. Here, Nyquist plot 201 can be a plot used to evaluate the stability of a system by parametric plots of the frequency response used in automatic control and signal processing. Nyquist plot 201 can be a plot that visualizes the response to frequency variations in the system on a complex plane including axes with real and imaginary components. The Nyquist plot of the impedance of the battery cell 200 according to the example embodiment can be, for example, a plot that visualizes a curve on a complex plane including axes with real and imaginary components, showing the impedance of the battery cell 200 based on the frequency variation of the AC power applied to the battery cell 200 at each of a plurality of temperatures.

[0044] In impedance spectroscopy, interpreting the electrochemical processes associated with the Nyquist plot of the battery cell 200 through impedance analysis can be related to analyzing multiple regions on the Nyquist plot. For example, region 240, which includes the intercept values ​​of the axis of the real component 220 containing impedance information, can be used to analyze the ohmic resistance associated with the characteristics of electrolyte ionic conductivity and external electrolyte resistance of the battery cell 200.

[0045] For example, the negative region 250 of the axis of the imaginary impedance 230, obtained based on the change in frequency 210, can be used to analyze information about the parasitic inductive component on the cell 200. Hereinafter, as described, in a pouch-type stacked cell, the inductive component can correspond to the resistive component resulting from the electrical characteristics that vary depending on the design of the cell 200.

[0046] For example, the second semicircular region 260, which acquires impedance information based on the change in frequency 210, can be used to analyze charge transfer impedance information, which is obtained through a charge transfer resistor (by...). The diagram illustrates the lithium-ion redox reaction at the electrode material interface, a phenomenon that occurs as charge moves across the electrode surface / interface of the battery cell 200. Therefore, information about the charge transfer resistance of the battery cell 200 can be obtained. For example, the linear region 270 obtained based on the change in frequency 210 can include Warburg impedance information obtained in the low-frequency region and can be used to analyze lithium-ion diffusion associated with the chemical diffusion resistance of lithium-ions (Li-ions) by intercalating into the particulate crystal structure within the battery cell 200.

[0047] According to this disclosure, the electronic device 100 can obtain the impedance of the battery cell 200 based on the variation of frequency 210 by performing EIS analysis on the battery cell 200 based on multiple temperatures (e.g., -30 degrees Celsius (°C) - 20°C, 0°C, and 25°C). For example, in the case of pouch-type stacked cells, the region 240 of the intercept value of the axis of the real impedance 220, which includes impedance information, and the negative region 250 of the axis of the imaginary impedance 230, which includes impedance information, can be mixed according to the inductive component that appears due to the electrical characteristics that vary depending on the design of the battery cell 200. Therefore, accurately identifying the resistance of the battery cell 200 can be difficult. Hereinafter, a method will be described in detail that considers the inductive component and the characteristics of the inductive component at multiple temperatures, uses these characteristics to determine the ohmic resistance of the battery cell 200, and determines the charge transfer resistance, mass transfer resistance, and total resistance.

[0048] Figure 3 This is a graph, based on an example embodiment, used to describe impedance information from electrochemical impedance spectroscopy (EIS) analyses performed on each temperature of the target battery cell.

[0049] refer to Figure 3 According to an example embodiment, the electronic device 100 can obtain a graph 301 of the impedance of a battery cell based on frequency changes by performing electrochemical impedance spectroscopy (EIS) analysis on a battery cell based on multiple temperatures including a first temperature and a second temperature. For example, the electronic device 100 can obtain a Nyquist graph using the graph 301 of the impedance of the battery cell and obtain multiple graphs (e.g., a first graph 311, a second graph 312, a graph 313, and a graph 314) of the impedance of the battery cell 200 based on the multiple temperatures included in the graph 301. Hereinafter, it will be described with reference to obtaining a first graph 311 of the impedance of the battery cell 200 based on frequency changes at a first temperature corresponding to a relatively low temperature (e.g., -30°C), and second graphs 312, 313, and 314 of the impedance of the battery cell 200 based on frequency changes at second temperatures above the first temperature (e.g., 20°C, 0°C, and 25°C).

[0050] Referring to the second curves 312, 313, and 314, it can be understood that the size of the semicircular region of the impedance information obtained from frequency changes in the first curve 311 is larger than the size of the semicircular region of the impedance information obtained from frequency changes in each of the second curves 312, 313, and 314. Furthermore, due to the influence of inductance, the ohmic resistance of each of the second curves 312, 313, and 314 is not clearly identified. In other words, when the battery cell 200 is a pouch-type stacked cell, as shown in the reference... Figure 3 As described, it can be difficult to clearly identify the ohmic resistance of the battery cell 200 by analyzing the region including the intercept value of the imaginary impedance axis of the graph. This can be identified by the second graphs 312, 313, and 314 of graph 302, which show the associated region of graph 301. In particular, in the case of region 362, which includes the intercept value of the real impedance axis of the second graph 312 at normal temperature, it can be identified that, due to the influence of the second inductance component of the battery cell 200 at the second temperature, even on the enlarged graph 302, the resistance will be affected by the above reference. Figure 2It is also difficult to distinguish the region of the real impedance axis intercept value, the negative region of the imaginary impedance axis, and the semicircular region obtained from the frequency change on the described Nyquist plot. Specifically, since the real impedance axis intercept value and the second inductance component of the second curve of the impedance of the battery cell 200 at the second temperature are mixed, it can be identified that it is difficult to clearly separate and analyze the ohmic resistance and the second inductance of the battery cell 200 at the second temperature.

[0051] Figure 4 This is a diagram illustrating the inductance of a battery cell according to an example embodiment, based on the temperature variation of the battery cell.

[0052] refer to Figure 4 The inductances 411, 412, 413, and 414 of the battery cell 200 at various temperatures can be identified using inductance chart 401 based on the temperature changes of the battery cell 200. Since the separation of ohmic resistance and inductance in a small cell is easy because the inductance is small when measuring impedance, the battery cell 200 can be represented by a small cell considering this. The inductances 411, 412, 413, and 414 of the battery cell 200 can be represented by a diagram corresponding to approximately 12 square centimeters (…). The area of ​​a small unit is used as a reference for measurement. (For example, the reference...) Figure 4 Identifiable inductors 411 at approximately 243 Kelvin (K), 412 at approximately 253 K, 413 at approximately 263 K, and 414 at approximately 273 K can all be identified as having a temperature of approximately 3.8 x Henry (H) to 3.6 x The value is within the range of H. That is, it can be identified that the difference in inductance between battery cells 200 based on temperature changes is small, and their inductance is continuously maintained. This can be understood as the inductance component corresponding to the electrical characteristics arising from the structural characteristics of the battery cell 200 not being significantly changed, because even if the temperature of the battery cell 200 changes, the structural characteristics of the battery cell 200 are not significantly changed. In other words, through this, the electronic device 100 according to the example embodiment can obtain the inductance component of a predetermined battery cell 200 at a predetermined temperature, and then determine the value of the inductance component as the inductance value of the same battery cell 200 at another temperature.

[0053] Figure 5 This is a flowchart describing an object electrode measurement method according to an example embodiment.

[0054] As referenced above Figure 3As described, in the case of bag-type stacked units, the size of the semicircular region for impedance information obtained based on frequency variation at a predetermined temperature (e.g., 20°C, 0°C, or 25°C) is smaller than the size of the semicircular region for impedance information obtained at temperatures below the predetermined temperature (e.g., -30°C). Furthermore, due to the inductive component, it is difficult to clearly identify the ohmic resistance by analyzing the region including the intercept values ​​of the real impedance axis of the graph. However, by using the reference above… Figure 4 The fact that the difference in inductance between the individual battery cells 200 based on temperature changes is not significant will be referred to below. Figure 5 A method for determining the resistance of a single battery cell 200 according to this disclosure is described.

[0055] refer to Figure 5 In operation S510, the electronic device 100 according to the example embodiment can obtain a graph of the impedance of the battery cell 200 based on frequency variation by performing an EIS analysis on the battery cell 200 based on multiple temperatures including a first temperature and a second temperature. As described above, the graph of the impedance of the battery cell 200 based on frequency variation can correspond to a Nyquist graph. In this case, as described above, the first temperature can correspond to a sub-zero temperature of approximately -30°C, and the second temperature can be a temperature higher than the first temperature and correspond to, for example, a normal temperature of approximately 25°C. The electronic device 100 according to the example embodiment can obtain a graph of the impedance of the battery cell 200 based on frequency variation by performing an EIS analysis on the battery cell 200 based on multiple temperatures including a first temperature and a second temperature. Figure 2 The impedance analysis described above is used to obtain a graph of the impedance of the battery cell 200 based on frequency changes, and to obtain a curve of the impedance of the battery cell 200 at multiple temperatures, including a first temperature and a second temperature, as referenced above. Figure 3 As described.

[0056] In operation S520, the electronic device 100 according to the example embodiment can extract the first inductance of the first graph of the impedance of the battery cell 200 at the first temperature. (Refer to the above...) Figure 3 The first curve describing the impedance of the battery cell 200 at the first temperature can correspond to the following curve: it is permissible to extract the first inductance by analyzing the negative region of the imaginary impedance axis of the impedance information obtained based on frequency changes using this curve, because this curve has a semicircular region of impedance information that is greater than that of the curves describing the impedance of the battery cell 200 at other temperatures.

[0057] In operation S530, the electronic device 100 according to the example embodiment can determine the resistance of the battery cell 200 at the second temperature based on the first inductance. (See reference...) Figure 4As described, since the inductance of the battery cell 200 does not change significantly with temperature changes and remains approximately constant, the electronic device 100 according to the example embodiment can determine the first inductance as the second inductance of the battery cell 200 at the second temperature.

[0058] According to an example embodiment, the electronic device 100 can determine the ohmic resistance of the battery cell 200 at the second temperature based on a value obtained by subtracting the second inductance from the intercept value of the real impedance axis of a second graph of the impedance of the battery cell 200 at the second temperature. (Refer to the above...) Figure 3 As described, since the ohmic resistance and inductive components are already mixed in the region including the intercept value of the real impedance axis of the second curve 312 at the second temperature, the electronic device 100 can eliminate the influence of inductance and separate the ohmic resistance at the second temperature by determining the ohmic resistance of the battery cell 200 at the second temperature based on the value obtained by subtracting the second inductance from the intercept value of the real impedance axis of the second curve. According to the example embodiment, the electronic device 100 can determine the charge transfer resistance of the battery cell 200 at the second temperature as the difference between the resistance at the inflection point of the second curve and the ohmic resistance of the battery cell 200 at the second temperature.

[0059] To verify the validity of the obtained ohmic resistance value, the electronic device 100 according to the example embodiment can obtain a reference ohmic resistance at the second temperature based on the relationship between the second temperature and the ohmic resistance of the battery cell 200 at the second temperature. When the difference between the reference ohmic resistance and the ohmic resistance of the battery cell 200 at the second temperature is less than a threshold, the ohmic resistance of the battery cell 200 at the second temperature is determined based on the value obtained by subtracting the second inductance from the intercept value of the real impedance axis of a second graph of the impedance of the battery cell 200 at the second temperature. In other words, the electronic device 100 according to the example embodiment can obtain a reference ohmic resistance based on the Arrhenius equation—this reference ohmic resistance includes information about the trend of ohmic resistance changing with temperature—and can compare the reference ohmic resistance with the ohmic resistance obtained according to this disclosure to verify whether the obtained ohmic resistance is an accurate value. References will follow below. Figure 6 Describe its details.

[0060] After obtaining the inductance, ohmic resistance, and charge transfer resistance of the battery cell 200 at the second temperature through the above operations, the electronic device 100 according to the example embodiment can determine the additional resistance component of the battery cell 200 by applying a pulse current to the battery cell 200 at the second temperature for a predetermined time. For example, the electronic device 100 according to the example embodiment can obtain the final total resistance based on the application of the pulse current, which is based on the change in the total resistance of the battery cell 200 at the second temperature. In this case, the final total resistance at the second temperature can be obtained based on the sum of the ohmic resistance, the charge transfer resistance, and the mass transfer resistance of the battery cell 200 at the second temperature. Reference will be made below. Figure 7 Describe its details.

[0061] Figure 6 This is a diagram illustrating the process of obtaining the ohmic resistance of a single battery cell according to an example embodiment.

[0062] As referenced above Figure 5 After determining the ohmic resistance of the battery cell 200 according to the present disclosure, the electronic device 100 according to the example embodiment can compare the ohmic resistance with a reference ohmic resistance determined based on the Arrhenius equation.

[0063] refer to Figure 6 According to the example embodiment, the electronic device 100 can obtain a reference ohmic resistance at a second temperature based on the Arrhenius equation. In this case, the reference ohmic resistance may correspond to the resistance obtained based on the relationship between absolute temperature and resistance according to the Arrhenius equation, and also to the resistance obtained by the method for verifying whether the ohmic resistance of the battery cell of this disclosure according to the example embodiment is within an appropriate range. In this case, the Arrhenius equation can be defined, for example, as follows.

[0064] [Equation 1]

[0065] In this context, "K" can represent the velocity constant. "A" can represent the frequency coefficient. "R" can represent the gas constant. "T" can represent the absolute temperature. "Activation energy can be represented. That is, according to the Arrhenius equation, the rate of chemical reaction increases as the absolute temperature of the system in which the chemical reaction occurs increases. When this is interpreted in terms of the cell 200, it can be considered that there is a relationship that promotes the movement of electrons. That is, according to the Arrhenius equation, the ohmic resistance of the cell 200 can decrease as the temperature of the cell 200 increases to correspond to this situation. For example, as can be recognized by Equation 1, the electronic device 100 according to the example embodiment can obtain a reference ohmic resistance at a second temperature based on the relationship that the ohmic resistance of the cell 200 decreases as the second temperature increases. Specifically, the reference ohmic resistance based on the Arrhenius equation according to temperature changes can be obtained in graph 601, as shown in graph 610."

[0066] When the difference between the reference ohmic resistance and the ohmic resistance of the battery cell 200 at the second temperature is less than a threshold, the electronic device 100 according to the example embodiment can determine the ohmic resistance of the battery cell 200 at the second temperature based on a value obtained by subtracting the second inductance from the intercept value of the real impedance axis of a second graph of the impedance of the battery cell 200 at the second temperature. Specifically, for example, the electronic device 100 according to the example embodiment can use values ​​611, 612, 613, and 614—its reference ohmic resistance—to determine the ohmic resistance of the battery cell 200 at the second temperature. Figure 5 The value obtained by subtracting the inductance from the intercept of the real impedance axis of a graph of the impedance of the battery cell 200 at a predetermined temperature is compared with a reference ohmic resistance based on the Arrhenius equation graph 610 at the same temperature. Values ​​611, 612, 613, and 614 can be determined as the ohmic resistance of the battery cell 200 when the corresponding difference is less than a threshold. In summary, the electronic device 100 according to the example embodiment can further rigorously determine the ohmic resistance of the battery cell 200 by comparing it with a reference ohmic resistance based on the Arrhenius equation, which is associated with temperature-based resistance changes, in addition to the value obtained by subtracting the inductance from the intercept of the real impedance axis of the graph of the impedance of the battery cell 200. Similarly, the electronic device 100 according to the example embodiment can perform the same process for the charge transfer resistance of the battery cell 200 to further rigorously determine the charge transfer resistance of the battery cell 200.

[0067] Figure 7 This is a diagram illustrating the process of obtaining the mass transfer resistance and total resistance of a single battery cell according to an example embodiment.

[0068] refer to Figure 7The change in the total resistance of a battery cell 200 can be identified by the resistance graph 701 of the battery cell 200 to which a pulsed current has been applied. According to the example embodiment, the electronic device 100 can apply a pulsed current to the battery cell 200 at a second temperature for a predetermined time, and obtain a final total resistance 711 based on the change in the total resistance of the battery cell 200 at the second temperature based on the application of the pulsed current. In this case, the final total resistance 711 can be obtained based on the sum of the ohmic resistance of the battery cell 200 at the second temperature, the charge transfer resistance of the battery cell 200 at the second temperature, and the mass transfer resistance of the battery cell 200 at the second temperature. Specifically, according to the example embodiment, the electronic device 100 can apply a pulsed current to the battery cell 200 for a predetermined time (e.g., 10 seconds), and determine the following variation amplitude as the sum of the ohmic resistance at the second temperature and the charge transfer resistance of the battery cell 200 at the second temperature: this variation amplitude is the variation amplitude of the total resistance of the battery cell 200 within an interval 712 where the rate of change of the total resistance of the battery cell 200 over time is greater than or equal to a threshold. In other words, the change in total resistance 711 during the interval 712 after the pulse current is applied to battery cell 200 can be defined as the sum of the ohmic resistance at the second temperature and the charge transfer resistance of battery cell 200 at the second temperature. According to the example embodiment, the electronic device 100 can determine the mass transfer resistance at the second temperature as the difference between the total resistance after the interval 712 and the final total resistance 711 at the final time point after the application of the pulse current. In other words, the final total resistance 711 at the second temperature can be defined as the sum of the ohmic resistance of battery cell 200 at the second temperature, the charge transfer resistance of battery cell 200 at the second temperature, and the mass transfer resistance 713 of battery cell 200 at the second temperature. In summary, after obtaining the ohmic resistance and charge transfer resistance of battery cell 200 at a predetermined temperature, the electronic device 100 according to the example embodiment can obtain the mass transfer resistance and final total resistance of battery cell 200 at a predetermined temperature by applying a pulse current for a predetermined time.

[0069] Figure 8 This is a block diagram illustrating an electronic device according to an example embodiment.

[0070] refer to Figure 8 The electronic device 100 according to the example embodiment may include processor 801 and processor 802. Regarding... Figure 6 The illustrated electronic device 100 illustrates specific elements associated with this example embodiment. Therefore, those skilled in the art, in conjunction with this example embodiment, will understand that, in addition to... Figure 6 In addition to the components illustrated, other commonly used components may be further included. In the example embodiment, the processor 802 may be included in the controller.

[0071] Processor 802 can control the overall operation of electronic device 100 and process data and signals. Processor 802 can be formed by at least one hardware unit. Alternatively, processor 802 can be operated by one or more software modules generated by executing program code stored in memory 801. Since processor 802 may include memory, processor 802 can control the overall operation of electronic device 100 and process data and signals by executing program code stored in memory.

[0072] The processor 802 can obtain a graph of the impedance of the battery cell 200 based on frequency changes by performing an EIS analysis on the battery cell 200 based on multiple temperatures, including a first temperature and a second temperature. It can then extract a first inductance from the first curve of the impedance of the battery cell 200 at the first temperature included in the graph, and determine the resistance of the battery cell 200 at the second temperature based on the first inductance. In this case, the second temperature may correspond to a temperature higher than the first temperature, and the processor 802 can determine the resistance, including the ohmic resistance and charge transfer resistance of the battery cell 200 at various temperatures, based on the characteristics of the inductance of the battery cell 200 described above.

[0073] In some example embodiments, electronic device 100 may additionally include a transceiver for performing wired / wireless communication. Electronic device 100 can communicate with external electronic devices (e.g., electronic device 100) using the transceiver. The external electronic device may be a terminal or a server. Furthermore, the communication technologies used by the transceiver may include Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Long Term Evolution (LTE), 5G, Wireless Local Area Network (WLAN), Wi-Fi, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), ZigBee, Near Field Communication (NFC), etc.

[0074] The server according to the above example embodiments may include a processor, a memory for storing and executing program data, permanent storage such as a disk drive, a communication port for communicating with external devices, and user interface devices such as touch panels, buttons, and keypads. Methods implemented by software modules or algorithms can be stored as computer-readable code or program instructions executable in a processor on a computer-readable recording medium. Here, the computer-readable recording medium may include magnetic storage media (e.g., read-only memory (ROM), random access memory (RAM), floppy disk, hard disk, etc.), optical reading media (e.g., CD-ROM or DVD), etc. The computer-readable recording medium can be distributed across a network-connected computer system, allowing the computer-readable code to be stored and executed in a distributed manner. The medium can be read by a computer, stored in memory, and executed by a processor.

[0075] This example embodiment can be represented by functional blocks and various processing steps. These functional blocks can be implemented by various numbers of hardware and / or software configurations that perform specific functions. For example, this example embodiment can employ integrated circuit configurations, such as memory, processors, logic circuits, and lookup tables, which can perform various functions by controlling one or more microprocessors or other control devices. Similar to these elements, which can be implemented by software programming or software elements, this example embodiment can be implemented by programming or scripting languages ​​such as C, C++, Java, and assembly languages, including various algorithms implemented by combinations of data structures, procedures, routines, or other programming configurations. Functional aspects can be implemented by algorithms executed by one or more processors. Additionally, this example embodiment can employ related techniques, such as those used for electronic environment setup, signal processing, and / or data processing. The terms “mechanism,” “element,” “device,” and “configuration” are used broadly and are not limited to mechanical and physical components. These terms can include the meaning of a series of software routines associated with a processor.

[0076] The above embodiments are merely examples, and other embodiments may be implemented within the scope of the appended claims.

Claims

1. A method for determining the resistance of a single battery cell, the method comprising: A graph of the impedance of the battery cell based on frequency variation is obtained by performing electrochemical impedance spectroscopy (EIS) analysis on the battery cell at multiple temperatures including a first temperature and a second temperature. The first inductance of the battery cell at the first temperature is extracted based on the first impedance curve of the battery cell included in the graph; and The resistance of the battery cell at the second temperature is determined based on the first inductance. The second temperature is a temperature higher than the first temperature.

2. The method according to claim 1, wherein determining the resistance of the battery cell at the second temperature comprises: The first inductor is determined to be the second inductor of the battery cell at the second temperature.

3. The method according to claim 1, wherein, Determining the resistance of the battery cell at the second temperature includes: The ohmic resistance of the battery cell at the second temperature is determined based on the value obtained by subtracting the second inductance from the intercept value of the real impedance axis of the second graph of the battery cell's impedance at the second temperature; and The difference between the resistance at the inflection point of the second curve and the ohmic resistance of the battery cell at the second temperature is determined as the charge transfer resistance of the battery cell at the second temperature.

4. The method according to claim 3, wherein, Determining the ohmic resistance of the battery cell at the second temperature includes: The reference ohmic resistance at the second temperature is obtained based on the relationship between the second temperature and the ohmic resistance of the battery cell at the second temperature; and When the difference between the reference ohmic resistance and the ohmic resistance of the battery cell at the second temperature is less than a threshold, the ohmic resistance of the battery cell at the second temperature is determined based on the value obtained by subtracting the second inductance from the intercept value of the real impedance axis of the second graph of the impedance of the battery cell at the second temperature.

5. The method of claim 1, further comprising: A pulse current is applied to the battery cell at the second temperature for a predetermined time; as well as Obtain the final total resistance, which is based on the change in the total resistance of the battery cell at the second temperature according to the application of the pulse current.

6. The method according to claim 5, wherein, Obtaining the final total resistance at the second temperature includes: obtaining the final total resistance at the second temperature based on the sum of the ohmic resistance of the battery cell at the second temperature, the charge transfer resistance of the battery cell at the second temperature, and the mass transfer resistance of the battery cell at the second temperature.

7. The method according to claim 1, wherein, The battery cell is a bag-type stacked cell having a positive electrode comprising active materials, conductive materials and a binder and a negative electrode comprising graphite, conductive materials and a binder stacked together.

8. The method of claim 1, wherein the second temperature is a normal temperature and the first temperature is a sub-zero temperature.

9. A non-transitory computer-readable recording medium, wherein a program for performing the method according to any one of claims 1-8 is recorded in the non-transitory computer-readable recording medium.

10. An electronic device, comprising: A memory configured to store instructions; as well as The processor is connected to the memory. The processor is configured as follows: A graph of the impedance of the battery cell based on frequency variation is obtained by performing electrochemical impedance spectroscopy (EIS) analysis on the battery cell at multiple temperatures, including a first temperature and a second temperature. Extract the first inductance from the first curve of the impedance of the battery cell at the first temperature included in the graph; and The resistance of the battery cell at the second temperature is determined based on the first inductance, and The second temperature is a temperature higher than the first temperature.

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