Battery safety assessment method based on electrochemical normalization model

Abstract

The invention provides a battery safety assessment method based on an electrochemical normalization model, and relates to the technical field of power systems. The method comprises the following steps: respectively modeling decomposition of a solid electrolyte interface, a reaction between an anode and an electrolyte, a reaction between a cathode and the electrolyte and a decomposition reaction of the electrolyte in the thermal runaway process of the battery based on an internal reaction mechanism of the thermal runaway process of the battery to obtain a four-step reaction temperature model; establishing a one-step global temperature model of the thermal runaway process of the battery based on the four-step reaction temperature model, inputting parameters of the target battery into the one-step global temperature model, and outputting a temperature safety range boundary of the thermal runaway process of the target battery; and evaluating the safety of the target battery based on the temperature safety range boundary. By adopting the scheme, the prediction of the thermal runaway characteristic of the battery is realized, and a reference is provided for the safe operation of the battery.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a battery safety assessment method and device based on an electrochemical normalization model. Background Art

[0002] As the global trend of decarbonization and electrification develops, the research and development of lithium-ion batteries (LIBs) has attracted widespread attention due to their applications in ground transportation and energy storage. One of the biggest challenges facing lithium-ion batteries is thermal runaway, where side reactions occur between battery materials under improper conditions such as overheating, overcharging, collision, and internal short circuit. These side reactions not only release heat and increase the battery temperature, but also release flammable gases and particles, which can cause subsequent combustion and fire, triggering a larger-scale spread of thermal runaway. Thermal runaway directly threatens life and property safety, and is therefore a key factor in future battery design and safety assessment. Summary of the invention

[0003] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, the first purpose of this application is to propose a battery safety assessment method based on an electrochemical normalization model, which realizes the prediction of battery thermal runaway characteristics and provides a reference for safe battery operation.

[0005] The second objective of this application is to propose a battery safety assessment device based on an electrochemical normalization model.

[0006] The third objective of the present application is to provide a computer device.

[0007] A fourth object of the present application is to provide a non-transitory computer-readable storage medium.

[0008] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a battery safety assessment method based on an electrochemical normalized model, including: based on the internal reaction mechanism of the battery thermal runaway process, the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte in the battery thermal runaway process are modeled respectively to obtain a four-step reaction temperature model; based on the four-step reaction temperature model, a one-step global temperature model of the battery thermal runaway process is established, and the parameters of the target battery are input into the one-step global temperature model to output the temperature safety range boundary of the target battery thermal runaway process; based on the temperature safety range boundary, the safety of the target battery is evaluated.

[0009] The battery safety assessment method based on the electrochemical normalization model of the embodiment of the present application realizes the prediction of the battery thermal runaway characteristics by combining the battery electrochemical model, the thermal runaway process, and the real-time status monitoring of the battery, thereby providing a reference for the safe operation of the battery.

[0010] Optionally, in one embodiment of the present application, modeling the decomposition of the solid electrolyte interface includes:

[0011] The thermal abuse reaction of a lithium-ion battery is represented by the first equation, where the first equation is:

[0012]

[0013] Among them, c sei is the dimensionless amount of lithium-containing metastable substances in the SEI film, A sei is the decomposition frequency factor of the SEI film, E a,sei is the activation energy of SEI decomposition, R is the ideal gas constant, T is the temperature, H is the reaction heat, and W is the density of the reactants in the medium.

[0014] Optionally, in one embodiment of the present application, modeling the reaction between the anode and the electrolyte includes:

[0015] The reaction between the anode and the electrolyte is represented by the second equation, where the second equation is:

[0016]

[0017] Among them, c ne A represents the dimensionless amount of lithium-containing metastable substances in graphite. ne Represents the frequency factor of the reaction between the negative electrode and the electrolyte, represents the dimensionless amount of lithium embedded in graphite, t sei represents the dimensionless thickness of the SEI film, t sei0 represents the reference SEI layer thickness, E a,ne represents the activation energy of SEI decomposition, R is the ideal gas constant, T is the temperature, H is the heat of reaction, and W is the density of the reactants in the medium.

[0018] Optionally, in one embodiment of the present application, modeling the reaction between the cathode and the electrolyte includes:

[0019] The reaction between the cathode and the electrolyte is represented by a third-party formula, where the third-party formula is:

[0020]

[0021] Among them, A pe Represents the frequency factor of the reaction between the positive electrode and the electrolyte, m pe,p1is the reaction order of α, m pe,p2 represents the reaction order of (1-α), E a,pe It represents the activation energy of the reaction between the positive electrode and the electrolyte, H is the heat of reaction, and W is the density of the reactants in the medium.

[0022] Optionally, in one embodiment of the present application, modeling the decomposition reaction of the electrolyte includes:

[0023] The exothermic decomposition of the electrolyte at high temperature is represented by the fourth equation, where the fourth equation is:

[0024]

[0025] Among them, A e represents the frequency factor of electrolyte decomposition, Indicates the proportion of remaining electrolyte, E a,e It represents the activation energy of electrolyte decomposition, R is the ideal gas constant, T is the temperature, H is the heat of reaction, and W is the density of the reactants in the medium.

[0026] Optionally, in one embodiment of the present application, a one-step global temperature model is established, which is expressed as:

[0027] The one-step global temperature model is expressed by the species and energy conservation laws, where the species and energy conservation laws are:

[0028]

[0029] Where R is the ideal gas constant, T is the temperature, and H is the heat of reaction. is the temperature rise rate value.

[0030] Optionally, in one embodiment of the present application, the parameters of the target battery are input into a one-step global temperature model, and the temperature safety range boundary of the thermal runaway process of the target battery is output, including:

[0031] The temperature rise rate value in the one-step global model is set based on the parameters of the target real battery, and the battery temperature is solved to obtain the upper and lower temperature bounds of the predicted battery thermal runaway process.

[0032] To achieve the above-mentioned purpose, the second embodiment of the present invention proposes a battery safety assessment device based on an electrochemical normalization model, comprising:

[0033] The reaction model building module is used to model the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte during the battery thermal runaway process based on the internal reaction mechanism of the battery thermal runaway process, and obtain a four-step reaction temperature model;

[0034] A global model building module is used to establish a one-step global temperature model of the battery thermal runaway process based on the four-step reaction temperature model, input the parameters of the target battery into the one-step global temperature model, and output the temperature safety range boundary of the target battery thermal runaway process;

[0035] The safety assessment module is used to assess the safety of the target battery based on the temperature safety range boundary.

[0036] To achieve the above-mentioned purpose, the third aspect of the present invention proposes a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned battery safety assessment method based on the electrochemical normalization model is implemented.

[0037] In order to achieve the above-mentioned objectives, the fourth aspect of the present invention proposes a non-temporary computer-readable storage medium, which, when the instructions in the storage medium are executed by a processor, can execute the above-mentioned battery safety assessment method based on the electrochemical normalization model.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A schematic diagram of a process of a battery safety assessment method based on an electrochemical normalization model provided in Example 1 of the present application;

[0041] Figure 2 A schematic diagram of the structure of a battery safety assessment device based on an electrochemical normalization model provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0043] Table 1 shows the meanings of the parameters involved in this application.

[0044] Table 1

[0045]

[0046]

[0047] The following describes a battery safety assessment method and device based on an electrochemical normalization model according to an embodiment of the present application with reference to the accompanying drawings.

[0048] Figure 1 A schematic flow chart of a battery safety assessment method based on an electrochemical normalization model provided in Example 1 of the present application.

[0049] like Figure 1 As shown, the battery safety assessment method based on the electrochemical normalization model includes the following steps:

[0050] Step 101, based on the internal reaction mechanism of the battery thermal runaway process, the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte in the battery thermal runaway process are modeled respectively to obtain a four-step reaction temperature model;

[0051] Step 102, establishing a one-step global temperature model of the battery thermal runaway process based on the four-step reaction temperature model, inputting the parameters of the target battery into the one-step global temperature model, and outputting the temperature safety range boundary of the target battery thermal runaway process;

[0052] Step 103 : Evaluate the safety of the target battery based on the temperature safety range boundary.

[0053] The battery safety assessment method based on the electrochemical normalization model in the embodiment of the present application starts from the modeling aspect, based on the concept of minimum ignition energy, evaluates the critical temperature of the hot spot that can trigger self-sustaining thermal runaway, and determines the safety range boundary of thermal runaway through calculation. Specifically, by combining the battery electrochemical model, the thermal runaway process, and the real-time status monitoring of the battery, the prediction of the battery thermal runaway characteristics is achieved, providing a reference for the safe operation of the battery.

[0054] The embodiment of the present application describes the battery through an electrochemical model, and the calculation complexity of the model is significantly reduced without a significant decrease in calculation accuracy; at the same time, a one-step global chemical method is used to determine the lower and upper limits of kinetic modeling, thereby achieving effective prediction of the thermal runaway characteristics of the battery.

[0055] Optionally, in one embodiment of the present application, the battery aging reaction mechanism is analyzed, specifically,

[0056] Thermal runaway side reactions usually include: decomposition of SEI film, melting of diaphragm, decomposition of positive electrode material, decomposition and combustion of electrolyte, etc. Generally speaking, when the temperature reaches about 70-100 degrees Celsius, the solid electrolyte interface separates and releases heat, and the battery temperature continues to rise. When the temperature reaches the melting point of the diaphragm, the diaphragm absorbs heat, melts and shrinks. The diaphragm material is usually made of polypropylene or polyethylene. At this time, the characteristic temperature is roughly 120-130 degrees Celsius. The significant increase in internal resistance is a typical feature after the diaphragm melts (Analysis of the aging effects on the thermal runaway characteristics of Lithium-Ion cells through stepwise reactions). As the side reactions continue to occur, due to the loss of diaphragm protection between the anode and the cathode, a short circuit will occur inside the battery and a large amount of heat will be released in a short time, and the temperature will rise rapidly. At this time, along with the decomposition of the positive electrode material and the electrolyte, oxygen may be released inside the battery, and then combustion will occur, and the highest temperature often reaches two or three hundred degrees Celsius.

[0057] Optionally, in one embodiment of the present application, modeling the decomposition of the solid electrolyte interface includes:

[0058] By listing the component reactions occurring at elevated temperatures, Li-ion battery thermal abuse reactions can be modeled for 3D battery simulations.

[0059] The negative electrode is protected from direct reaction with the solvent by a layer of ion-conducting membrane called solid electrolyte interface (SEI). This layer is metastable and can decompose exothermically at 90–120 °C. The reaction can be expressed by the following equation:

[0060]

[0061] Optionally, in one embodiment of the present application, modeling the reaction between the anode and the electrolyte includes:

[0062] At high temperatures (>120°C), an exothermic reaction occurs between the intercalated lithium and the electrolyte, as shown below:

[0063]

[0064] Optionally, in one embodiment of the present application, modeling the reaction between the cathode and the electrolyte includes:

[0065] In the oxidized state, the cathode material reacts directly with the electrolyte. Alternatively, the cathode active material can decompose exothermically and release oxygen, which can react exothermically with the electrolyte. In either case, the chemical reduction of the cathode active material with the electrolyte is highly exothermic (Eq.

[0066]

[0067] Optionally, in one embodiment of the present application, modeling the decomposition reaction of the electrolyte includes:

[0068] The electrolyte will decompose exothermically at high temperature (>200°C), as shown in the following formula:

[0069]

[0070] Optionally, in one embodiment of the present application, establishing a one-step global temperature model includes:

[0071] For actual operation, the four-step thermal runaway model has the disadvantages of complex parameters and cumbersome solutions. In order to solve the challenges brought by the parameter optimization of the four-step thermal runaway model and the inherent battery variability in the thermal runaway test, this embodiment proposes a thermal runaway statistical analysis method based on a one-step overall chemical model. In this embodiment, a one-step global chemical model in Arrhenius form can be uniquely determined from the four-step reaction process. By directly statistically analyzing the one-step global mechanism of each battery, the mean and standard deviation of the frequency factor and activation energy can be easily obtained. The changes in the frequency factor and activation energy can then be used to quantify the uncertainty range of the thermal runaway chemistry. By comparing the experimental data with the nominal values ​​and uncertainty ranges of the modeling, a more rigorous assessment of battery safety can be made based on statistical analysis.

[0072] The one-step global model will employ the following species and energy conservation laws:

[0073]

[0074] Where H is the overall enthalpy change of the thermal runaway process, H = c p ΔT=c p (T3-T1), is the temperature rise rate value, so the above formula has nothing to do with the thermal capacity parameters of the battery itself.

[0075] Among them, delta T has a strong correlation with the battery state of charge. When the battery SOC is high, the proportion of active materials inside the battery is high, and the maximum temperature that can be reached during thermal runaway, namely T3, also increases accordingly, while the starting temperature of battery thermal runaway decreases accordingly. At this time, delta T will also increase.

[0076] Through statistical analysis, the frequency factor A can be expressed as 3.49E8±2.40E8 min-1, and the global activation energy is 8.58E4±2.04E3 J / mol. Compared with the frequency factor, the global activation energy shows a smaller percentage change.

[0077] Optionally, in one embodiment of the present application, the temperature rise rate value in the formula is set according to the parameters obtained in the above process. The temperature is 0.02℃ / min and solved. It can be seen intuitively that the upper limit of the predicted exothermic onset temperature Texo (110.2℃) occurs when A takes the minimum value and E takes the maximum value, while the lower limit predicted by Texo (71.8℃) occurs when A takes the maximum value and E takes the minimum value. When both A and E take the average value, the nominal value of the onset temperature (86.5℃) can be obtained.

[0078] In order to implement the above-mentioned embodiment, the present application also proposes a battery safety assessment device based on an electrochemical normalization model.

[0079] Figure 2 A schematic diagram of the structure of a battery safety assessment device based on an electrochemical normalization model provided in an embodiment of the present application.

[0080] like Figure 2 As shown, the battery safety assessment device based on the electrochemical normalization model includes:

[0081] The reaction model building module is used to model the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte during the battery thermal runaway process based on the internal reaction mechanism of the battery thermal runaway process, and obtain a four-step reaction temperature model;

[0082] A global model building module is used to establish a one-step global temperature model of the battery thermal runaway process based on the four-step reaction temperature model, input the parameters of the target battery into the one-step global temperature model, and output the temperature safety range boundary of the target battery thermal runaway process;

[0083] The safety assessment module is used to assess the safety of the target battery based on the temperature safety range boundary.

[0084] It should be noted that the aforementioned explanation of the embodiment of the battery safety assessment method based on the electrochemical normalization model is also applicable to the battery safety assessment device based on the electrochemical normalization model of this embodiment, and will not be repeated here.

[0085] In order to implement the above embodiments, the present invention further proposes a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method described in the above embodiments is implemented.

[0086] In order to implement the above embodiments, the present invention further proposes a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method of the above embodiments is implemented.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0088] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0089] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0090] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0091] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0092] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0093] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0094] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A battery safety assessment method based on an electrochemical normalization model, characterized in that: include: Based on the internal reaction mechanism of the battery thermal runaway process, the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte during the battery thermal runaway process are modeled separately to obtain a four-step reaction temperature model. Establishing a one-step global temperature model of the battery thermal runaway process based on the four-step reaction temperature model, inputting the parameters of the target battery into the one-step global temperature model, and outputting the temperature safety range boundary of the target battery thermal runaway process; The safety of the target battery is evaluated based on the temperature safety range boundary.

2. The method according to claim 1, characterized in that Model the decomposition of solid electrolyte interfaces, including: The thermal abuse reaction of a lithium-ion battery is represented by a first equation, wherein the first equation is: Among them, c sei is the dimensionless amount of lithium-containing metastable substances in the SEI film, A sei is the decomposition frequency factor of the SEI film, E a,sei is the activation energy of SEI decomposition, R is the ideal gas constant, T is the temperature, H is the reaction heat, and W is the density of the reactants in the medium.

3. The method according to claim 1, characterized in that Model the reactions between the anode and the electrolyte, including: The reaction between the anode and the electrolyte is represented by the second equation, wherein the second equation is: Among them, c ne A represents the dimensionless amount of lithium-containing metastable substances in graphite. ne Represents the frequency factor of the reaction between the negative electrode and the electrolyte, represents the dimensionless amount of lithium embedded in graphite, t sei represents the dimensionless thickness of the SEI film, t sei0 represents the reference SEI layer thickness, E a,ne represents the activation energy of SEI decomposition, R is the ideal gas constant, T is the temperature, H is the heat of reaction, and W is the density of the reactants in the medium.

4. The method according to claim 1, characterized in that Model the reactions between the cathode and the electrolyte, including: The reaction between the cathode and the electrolyte is represented by a third-party formula, wherein the third-party formula is: Among them, A pe Represents the frequency factor of the reaction between the positive electrode and the electrolyte, m pe,p1 is the reaction order of α, m pe,p2 represents the reaction order of (1-α), E a,pe It represents the activation energy of the reaction between the positive electrode and the electrolyte, H is the heat of reaction, and W is the density of the reactants in the medium.

5. The method according to claim 1, characterized in that Modeling of electrolyte decomposition reactions including: The exothermic decomposition of the electrolyte at high temperature is represented by the fourth equation, wherein the fourth equation is: Among them, A e represents the frequency factor of electrolyte decomposition, Indicates the proportion of remaining electrolyte, E a,e It represents the activation energy of electrolyte decomposition, R is the ideal gas constant, T is the temperature, H is the heat of reaction, and W is the density of the reactants in the medium.

6. The method according to claim 1, characterized in that Establishing the one-step global temperature model comprises: The one-step global temperature model is represented by species and energy conservation laws, where the species and energy conservation laws are: Where R is the ideal gas constant, T is the temperature, and H is the heat of reaction. is the temperature rise rate value.

7. The method according to claim 6, characterized in that The step of inputting the parameters of the target battery into the one-step global temperature model and outputting the temperature safety range boundary of the thermal runaway process of the target battery includes: The temperature rise rate value in the one-step global model is set based on the parameters of the target real battery, and the battery temperature is solved to obtain the upper and lower temperature bounds of the predicted battery thermal runaway process.

8. A battery safety assessment device based on an electrochemical normalization model, characterized in that: include: The reaction model building module is used to model the decomposition of the solid electrolyte interface, the reaction between the anode and the electrolyte, the reaction between the cathode and the electrolyte, and the decomposition reaction of the electrolyte during the battery thermal runaway process based on the internal reaction mechanism of the battery thermal runaway process, and obtain a four-step reaction temperature model; A global model building module, used to establish a one-step global temperature model of the battery thermal runaway process based on the four-step reaction temperature model, input the parameters of the target battery into the one-step global temperature model, and output the temperature safety range boundary of the target battery thermal runaway process; The safety assessment module is used to assess the safety of the target battery based on the temperature safety range boundary.

9. A computer device, characterized in that: The method comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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