Method for diagnosing an energy storage unit of an aerosol generation device, aerosol generation device and computer program

Abstract

The present disclosure relates to a method for diagnosing an energy storage unit of an aerosol generation device, the method comprising: applying a periodically varying current to the energy storage unit; measuring a plurality of impedance values of the energy storage unit, wherein each impedance value is measured at one frequency of a set of independent spaced-apart frequencies of the periodically varying current; and determining, based on the plurality of impedance values, whether the energy storage unit is suitable for further use in the aerosol generation device.

Description

Technical Field

[0001] This disclosure relates to a method for diagnosing the energy storage unit of an aerosol generating device, an aerosol generating device, and a computer program. Background Technology

[0002] An aerosol generating device is a portable (i.e., handheld) device that heats (without burning or igniting) aerosol-generating material to a temperature typically in the range of 150°C to 300°C to produce vapor, which is then typically cooled and condensed to form an aerosol for the user to inhale. Common aerosol generating devices use one of a variety of different technologies to heat the aerosol-generating material. All of these technologies require some form of internal energy source. This energy is typically provided as electricity, provided by an energy storage unit (such as a battery or capacitor) that is usually charged by an external power source.

[0003] For reliable operation, energy storage units require regular monitoring. This may include diagnostics based on performance metrics such as the energy storage unit's State of Charge (SoC) and State of Health (SoH). SoC is typically defined as the current value of the remaining (electrical) charge capacity of the energy storage unit, relative to its (current) maximum charge capacity. SoH is typically defined as the current value of the maximum charge capacity (of an aging storage unit), relative to its original maximum charge value (i.e., when the energy storage unit is new, for example, with zero or near-zero charge / discharge cycles). Alternatively, SoH can be defined as the current value of the energy storage unit's internal resistance, relative to its original internal resistance value. Generally, both SoC and SoH are expressed as percentages [%]. Other electrical parameters of the energy storage unit, such as internal resistance or capacitance, can also be used as performance metrics. Summary of the Invention

[0004] Because performing the necessary measurements and analyzing the measurement data takes time, diagnosing the energy storage units of aerosol generating devices can require significant computational resources and may result in downtime that prevents the aerosol generating device from operating at full capacity. Therefore, it is necessary to reduce the computational resources and time required to diagnose the energy storage units of aerosol generating devices, and more generally, to improve the diagnostics process for energy storage units.

[0005] One embodiment relates to a method for diagnosing an energy storage unit of an aerosol generating apparatus. The method includes applying a periodically varying current to the energy storage unit. The method further includes measuring a plurality of impedance values ​​of the energy storage unit, wherein each impedance value is measured at one frequency from a set of independently spaced frequencies of the periodically varying current. The method further includes determining, based on the plurality of impedance values, whether the energy storage unit is suitable for further use in the aerosol generating apparatus.

[0006] Another embodiment relates to an aerosol generating apparatus including a control unit configured to perform the method according to the embodiment. Further preferred embodiments are defined in the dependent claims.

[0007] The method according to the embodiments can reduce the computational resources and time required to diagnose the energy storage unit of an aerosol generating device.

[0008] Further embodiments of the present invention are as follows: Example E1. A method for diagnosing the energy storage unit of an aerosol generating device, the method comprising: A periodically varying current is applied to the energy storage unit; Multiple impedance values ​​of the energy storage unit are measured, wherein each impedance value is measured at one frequency of a set of independently spaced frequencies of the periodically changing current; and Based on these multiple impedance values, it is determined whether the energy storage unit is suitable for further use in the aerosol generating device.

[0009] Example E2. The method according to claim E1, wherein measuring each impedance value includes controlling the periodically varying current to have a corresponding frequency among the independently spaced frequencies in the set.

[0010] Example E3. The method according to any one of Examples E1 to E2, wherein the plurality of impedance values ​​include: The first impedance value of the energy storage unit measured at the first frequency of the periodically changing current; The second impedance value of the energy storage unit measured at the second frequency of the periodically changing current; The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the first impedance value and the second impedance value are greater than a corresponding threshold; and The ratio of the second frequency to the first frequency is between 20 and 500,000.

[0011] Example E4. The method according to Example E3, wherein the first frequency is between 0.1 Hz and 50 Hz, and / or the second frequency is between 1 kHz and 50 kHz.

[0012] Example E5. The method according to any one of Examples E3 to E4, wherein each of these corresponding thresholds is based on one or more of the state of charge (SoC) of the energy storage unit and the temperature of the energy storage unit.

[0013] Example E6. The method according to any one of Examples E1 to E5, Among these, the plurality of impedance values ​​includes at least three impedance values, and The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on the reconstructed electrochemical impedance spectroscopy obtained by fitting a mathematical function representing a curve in a complex plane to the at least three impedance values.

[0014] Example E7. The method according to Example E6, wherein the third frequency is between 50 Hz and 1 kHz.

[0015] Example E8. The method according to any one of Examples E6 to E7, wherein the plurality of impedance values ​​includes at most five impedance values.

[0016] Example E9. The method according to any one of Examples E6 to E8, wherein the mathematical function corresponds to a semicircle in the complex plane.

[0017] Example E10. The method according to any one of Examples E6 to E9, The reconstructed electrochemical impedance spectroscopy indicates electrolyte resistance, charge transfer resistance, and interfacial capacitance. The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the electrolyte resistance, the charge transfer resistance, and the interface capacitance are greater than the corresponding threshold.

[0018] Example E11. An aerosol generating apparatus, comprising: Energy storage unit; An inverter unit configured to generate a periodically varying current applied to the energy storage unit; and Control unit, which is configured to: Multiple impedance values ​​of the energy storage unit are measured, wherein each impedance value is measured at one frequency of a set of independently spaced frequencies of the periodically changing current; and Based on these multiple impedance values, it is determined whether the energy storage unit is suitable for further use in the aerosol generating device.

[0019] Example E12. The aerosol generating apparatus according to Example E11, wherein the control unit is configured to measure each impedance value by controlling the periodically varying current to have a corresponding frequency in the set of independently spaced frequencies.

[0020] Example E13. The aerosol generating apparatus according to Example E11 or E12, wherein the plurality of impedance values ​​include: The first impedance value of the energy storage unit measured at the first frequency of the periodically changing current; The second impedance value of the energy storage unit measured at the second frequency of the periodically changing current; The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the first impedance value and the second impedance value are greater than a corresponding threshold; and The ratio of the second frequency to the first frequency is between 20 and 500,000.

[0021] Example E14. An aerosol generating apparatus according to any one of Examples E11 to E13, wherein the first frequency is between 0.1 Hz and 50 Hz, and / or the second frequency is between 1 kHz and 50 kHz.

[0022] Example E15. An aerosol generating apparatus according to any one of Examples E11 to E14, wherein each of these corresponding thresholds is based on one or more of the state of charge (SoC) of the energy storage unit and the temperature of the energy storage unit.

[0023] Example E16. An aerosol generating apparatus according to any one of Examples E11 to E15, wherein the plurality of impedance values ​​includes at least three impedance values, and

[0024] The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on the reconstructed electrochemical impedance spectroscopy obtained by fitting a mathematical function representing a curve in a complex plane to the at least three impedance values.

[0025] Example E17. The aerosol generating apparatus according to Example E16, wherein the third frequency is between 50 Hz and 1 kHz.

[0026] Example E18. An aerosol generating apparatus according to any one of Examples E16 to E17, wherein the plurality of impedance values ​​includes at most five impedance values.

[0027] Example E19. An aerosol generating apparatus according to any one of Examples E16 to E18, wherein the mathematical function corresponds to a semicircle in the complex plane.

[0028] Example E20. An aerosol generating apparatus according to any one of Examples E16 to E19, wherein the reconstructed electrochemical impedance spectroscopy indicates electrolyte resistance, charge transfer resistance, and interfacial capacitance, and

[0029] The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the electrolyte resistance, the charge transfer resistance, and the interface capacitance are greater than the corresponding threshold.

[0030] Example E21. A computer program including instructions that, when executed by a computer, cause the computer to perform the method as described in any one of Examples E1 to E10. Attached Figure Description

[0031] Embodiments of this disclosure will now be described with reference to the accompanying drawings, which are provided to better understand the concept of the invention but should not be construed as limiting the invention. In the drawings: Figure 1 A simplified diagram of an aerosol generating apparatus according to an embodiment is shown; Figure 2 A flowchart is shown of a method for diagnosing the energy storage unit of an aerosol generating device according to an embodiment; Figure 3A The low-frequency resistance R of the energy storage unit is shown. LF Exemplary evolution relative to its number of charges / cycles; Figure 3B The high-frequency resistor R of the energy storage unit is shown. HF Exemplary evolution relative to its number of charges / cycles; Figure 4 Multiple reconstructed electrochemical impedance spectra for multiple energy storage units are shown, which are fitted to multiple measurement points; Figure 5 The Nyquist plot showing the idealized electrochemical impedance spectrum including a semicircle is shown; Figure 6 A schematic representation of lithium-ion mass transfer phenomena occurring in lithium-ion battery electrodes and the corresponding Nyquist plots of these lithium-ion mass transfer phenomena are shown. Figure 7 The charge transfer resistance R of the energy storage unit is shown. cf Exemplary evolution relative to its number of charges / cycles; Figure 8 A block diagram of a computer suitable for performing the methods according to embodiments is shown. Detailed Implementation

[0032] This disclosure will now be described in conjunction with specific embodiments. These embodiments are intended to provide a better understanding to those skilled in the art and are not intended to limit the scope of this disclosure as defined by the appended claims in any way. In particular, embodiments described independently throughout the specification may be combined to form further embodiments, provided that they are not mutually exclusive.

[0033] Typically, aerosol generating devices are electrical devices that heat aerosol-generating materials to produce an aerosol for the user to inhale. The aerosol-generating materials are heated to temperatures typically in the range of 150°C to 300°C, producing vapor without burning or igniting the materials. The vapor then cools and condenses, forming the aerosol for the user to inhale. Aerosol generating devices are typically supplied in portable (i.e., handheld) sizes and include an energy storage unit that acts as an internal energy source for the device. This energy storage unit provides electrical power to the aerosol generating device. The energy storage unit can store energy as an electrochemical potential between electrodes. Electrochemical energy is converted into electrical energy through a chemical reaction, whereby electrons are transferred between the electrodes via a circuit. The energy storage unit can be a rechargeable battery.

[0034] Figure 1 A simplified diagram of an aerosol generating apparatus 10 according to an embodiment is shown. The aerosol generating apparatus 10 includes an energy storage unit 11. The energy storage unit 11 may be a rechargeable battery, such as a lithium-ion battery. The rechargeable battery may include one or more individual battery cells.

[0035] The aerosol generating device 10 further includes an inverter unit 12 configured to generate a periodically varying current applied to and / or drawn from the energy storage unit 11. The inverter unit 12 can receive input current and / or voltage supplied from an external power source; in this case, the inverter unit 12 converts the input current and / or voltage into a periodically varying current. This periodically varying current can vary at a certain frequency, and the inverter unit 12 can change the frequency by adjusting internal switching operations. As an example, the input current and / or voltage can be received via an external power source during the charging process of the energy storage unit 11. The aerosol generating device 10 may include a charging port for electrical connection to an external power source and / or an external computing device. The charging port is not limited to a physical connection to an external power source and may additionally or alternatively employ a wireless connection. The charging port may further be capable of receiving and transmitting data. As an example, the charging port may be a Universal Serial Bus (USB) port. Alternatively, the inverter unit 12 can receive input current and / or voltage supplied from a secondary internal energy source (e.g., another battery or capacitor). The aerosol generating device 10 further includes a control unit 13 configured to measure a plurality of impedance values ​​of the energy storage unit, wherein each impedance value is measured at one of a set of independently spaced frequencies of a periodically varying current. Furthermore, the control unit 13 can be configured to determine, based on the plurality of impedance values, whether the energy storage unit 11 is suitable for further use in the aerosol generating device 10. Moreover, the control unit 13 can be configured to perform a method for diagnosing the energy storage unit 11. Further details regarding this method will be provided later. Figure 2 Please provide an explanation.

[0036] For ease of explanation, further details of the aerosol generating device 10 are described, and it is self-evident that these details may be omitted. The aerosol generating device 10 may further include a heating chamber 14 arranged to receive an aerosol generating article 20. The aerosol generating article 20 may be generally cylindrical and includes an aerosol generating material 21. At its proximal end, the aerosol generating article 20 may include a mouthpiece 22 having an outlet through which a user can inhale (i.e., inhale) the aerosol generated by heating the aerosol generating material 21. The aerosol generating material 21 may include any type of solid, semi-solid, and liquid material. The aerosol generating material 21 may include plant-derived materials such as tobacco.

[0037] The aerosol generating apparatus 10 may further include one or more heating elements 15 arranged to heat the aerosol generating material 21. As an example, the one or more heating elements 15 may be provided as an induction heater having an induction coil wound around a heating chamber 14 to generate an alternating electromagnetic field therein. The inverter unit 12 may be further configured to receive direct current from the energy storage unit 11 and generate alternating current applied to the one or more heating elements 15. However, this disclosure is not limited to induction heaters; in fact, other heaters are also suitable for implementing this disclosure.

[0038] When one or more heating elements 15 are provided as induction heaters, the aerosol generating article 20 may include one or more sensors (not shown) that are coupled to an electromagnetic field and generate heat due to eddy currents and / or hysteresis, which is then transferred from the sensors to the aerosol generating material 21. As an example, the heating chamber 14 itself may be used as a sensor by being formed of a high-permeability material (e.g., permalloy). As another example, the sensor may be embedded within the aerosol generating material 21 of the aerosol generating article 20. A combination of both may also be used.

[0039] Alternatively, one or more heating elements 15 may be provided as resistance heaters. Other aerosol generating devices may be used, including devices configured to generate aerosols without heating elements, for example, by atomizing a liquid aerosol forming matrix using an ultrasonic transducer.

[0040] The control unit 13 may be further configured to control other operations of the aerosol generating device 10, such as controlling the amount of current or voltage supplied to or from the energy storage unit 11, the inverter unit 12, and / or one or more heating elements 15. The control unit 13 may also be optionally configured to communicate with an external computing device coupled to it. The external computing device may be coupled via a wired connection (e.g., via a charging port) or a wireless connection (e.g., via Bluetooth, Wi-Fi, etc.). The control unit 13 may be further configured to track the number of charge / discharge cycles of the energy storage unit 11.

[0041] The aerosol generating device 10 may optionally include one or more temperature sensors arranged to measure the corresponding temperature of one or more components of the aerosol generating device 10 (e.g., energy storage unit 11 or sensors). The aerosol generating device 10 may optionally include one or more current and / or voltage sensors arranged to measure the corresponding current and / or voltage applied to one or more components of the aerosol generating device 10. The aerosol generating device 10 may optionally include a communication unit configured to transmit and / or receive signals (e.g., via Bluetooth, Wi-Fi, etc.).

[0042] The aerosol generating device 10 may optionally include a user interface unit configured to notify a user of the status of the aerosol generating device 10. This status may indicate whether the aerosol generating device 10 is suitable for further use. The interface unit may be provided using a light-emitting diode (LED) for generating visual notifications, a speaker for generating auditory notifications, or a vibration motor for generating tactile notifications. Alternatively, notifications regarding the status may be transmitted to an external computing device via a communication unit.

[0043] Figure 2 A flowchart of a method 1000 for diagnosing an energy storage unit of an aerosol generating device according to an embodiment is shown. Method 1000 preferably includes steps S1100 to S1300.

[0044] Step S1100 includes applying a periodically varying current to the energy storage unit. This periodically varying current can be alternating current (AC). Alternatively, the periodically varying current can be pulsating direct current (DC). In this way, the energy storage unit 11 can optionally be charged while performing diagnostics. As an example, pulsating DC can be generated by chopping a constant DC power supply from an external power source or rectifying an AC power supply. As another example, pulsating DC can be generated by adding an AC power supply to a constant DC power supply, wherein at each time point, the absolute value of the AC power supply is less than that of the constant DC power supply. As yet another example, pulsating DC can be generated by taking the maximum value of the AC power supply and the constant DC power supply at each time point.

[0045] Step S1200 includes measuring multiple impedance values ​​of the energy storage unit, wherein each impedance value is measured at one of a set of independently spaced frequencies of a periodically changing current. This measurement at the spaced frequencies can be performed by repeating each measurement in step S1200 after the inverter unit 12 changes its frequency. The control unit 13 can communicate with the inverter unit 12 to control the value of the frequency applied to or drawn from the energy storage unit 11. The impedance values ​​can be given in ohms (Ω). In one example, the set of independently spaced frequencies can be represented as {f1, f2, ..., f...} N}, where N is a positive integer. In this example, "independently spaced" means the frequency difference Δf between adjacent frequencies in the group. i = f i+1 – f i (Where i = 1, 2, ..., N-1) forms an irregular sequence of values. In other words, in this example, the frequency difference Δf i The non-uniform spacing makes it impossible to determine a particular frequency in the group based solely on knowledge of the other frequencies in the group. In other words, in this example, all frequencies in the group are determined independently of each other. Specifically, this group of independently spaced frequencies does not correspond to a frequency scan, i.e., a set of equally spaced frequencies. This group of independently spaced frequencies can be predetermined.

[0046] Step S1300 includes determining whether the energy storage unit 11 is suitable for further use in the aerosol generating device 10 based on a plurality of impedance values. The energy storage unit 11 is considered suitable for further use when one or more of the plurality of impedance values ​​are determined to meet one or more predetermined conditions. Each of the predetermined conditions may indicate an acceptable deviation from a target value. Meeting a predetermined condition means that the determined impedance value is within that acceptable deviation. Here, "acceptable deviation" may be a deviation in which the energy storage unit 11 can still be used safely and / or maintain sufficient performance to continue powering the aerosol generating device 10. Exceeding this acceptable deviation may indicate that the energy storage 11 has degraded and / or may cause problems (e.g., short circuits).

[0047] By measuring the impedance value at each independently spaced frequency of the periodically varying current applied to the energy storage unit, the computational resources and time required to diagnose the energy storage unit 11 of the aerosol generating device can be reduced. In particular, it is possible to reliably determine whether the energy storage unit 11 is suitable for further use in the aerosol generating device 10 using fewer computational resources and time than conventional diagnostic methods. Thus, improved diagnostics can be achieved.

[0048] In conventional diagnostic methods, a wider range of impedance values ​​can be determined by continuously sweeping frequencies from high to low (or from low to high) to apply and / or draw periodically varying currents at more frequencies from the energy storage unit 11. This conventional diagnostic method allows for the accurate measurement of multiple parameters representing the characteristics of the energy storage unit 11. However, such arduous and complex calculations can place an excessive burden on the aerosol generating device 10. The proposed diagnostic method aims to determine whether the energy storage unit 11 is suitable for further use, rather than precisely measuring every parameter. Therefore, by employing independently spaced frequencies, an optimized diagnostic method for the aerosol generating device 10 can be achieved.

[0049] Measuring each impedance value may include controlling a periodically varying current to have (at least) a corresponding frequency from the set of independently spaced frequencies. In other words, the periodically varying current may be adjusted so that its frequency corresponds to (at least) one of the set of independently spaced frequencies.

[0050] The plurality of impedance values ​​may include a first impedance value of the energy storage unit 11 measured at a first frequency of a periodically changing current, and a second impedance value of the energy storage unit 11 measured at a second frequency of a periodically changing current, wherein the ratio of the second frequency to the first frequency is between 20 and 500,000 (therefore, the first frequency is different from the second frequency). Furthermore, determining whether the energy storage unit 11 is suitable for further use in the aerosol generating device 10 can be based on whether one or more of the first and second impedance values ​​are greater than a corresponding threshold. Generally, as the energy storage unit degrades, the impedance values ​​tend to increase. Therefore, if one or more of the first and second impedance values ​​are greater than the corresponding threshold, the control unit 13 can determine that the energy storage unit 11 is not suitable for further use. In other words, the second frequency may be 20 to 500,000 times the first frequency. Otherwise, it can be determined that the energy storage unit 11 is not suitable for further use.

[0051] For a complex impedance value Z = R + iX, the comparison with the corresponding threshold can be made based on the real part Re(Z) = R (sometimes also denoted as Z') of the impedance value Z (i.e., the resistance value R).

[0052] The first frequency can be between 0.1 Hz and 50 Hz. Alternatively or supplementarily, the second frequency can be between 1 kHz and 50 kHz. As an example, the first frequency can be 10 Hz, and the second frequency can be 1 kHz. In this case, the ratio of the second frequency to the first frequency is 100.

[0053] Figure 3AThe low-frequency resistance R of the energy storage unit is shown. LF An exemplary evolution relative to its number of charge / cycle cycles. In one example, the low-frequency resistor R LF This can correspond to the real part of the first impedance value measured at the first frequency of 10 Hz. Figure 3B The high-frequency resistor R of the energy storage unit is shown. HF An exemplary evolution relative to its number of charge / cycle cycles. In one example, the high-frequency resistor R HF This can correspond to the real part of the second impedance value measured at a second frequency of 1 kHz (in this case, the high-frequency resistance R). HF It can also be referred to as the 1 kHz resistor R 1kHz It can be observed that the degradation of the energy storage unit 11 intensifies with the number of charge / discharge cycles. In other words, due to the progression of degradation of the energy storage unit 11, the low-frequency resistance R can be observed to increase. LF and high-frequency resistor R HF The number of charge / cycle cycles has increased. Therefore, the degree of degradation can be obtained by comparing the first and second impedance values ​​with corresponding thresholds. Figure 3A and Figure 3B In one example, because the low-frequency resistance exceeds the corresponding threshold, it can be determined that the energy storage unit 11 is unsuitable for further use in the aerosol generating device 10. In another example (not depicted), when the corresponding (high-frequency) resistance exceeds the corresponding threshold, it can be determined that the energy storage unit 11 is unsuitable for further use. In another example (not depicted), when both the low-frequency resistance value and the high-frequency resistance exceed the corresponding threshold, it can be determined that the energy storage unit 11 is unsuitable for further use. Alternatively, the high-frequency resistance value R can be defined in a different way. HF and low-frequency resistance value R LF The degree of degradation relative to the corresponding threshold. According to this alternative definition, the degree of degradation can be expressed as a simulated value.

[0054] In practice, other parameters of the energy storage unit, such as state of charge (SoC) and temperature, can affect the measurement of multiple impedance values. SoC can be defined as the current value of the remaining (electrical) charge capacity of the energy storage unit 11, relative to the current value of the maximum charge capacity of the energy storage unit. Temperature can be the internal temperature of the energy storage unit.

[0055] Each of these corresponding thresholds can be based on one or more of the state of charge (SoC) of the energy storage unit 11 and the temperature of the energy storage unit. In other words, each of these corresponding thresholds can be offset based on the SoC and / or temperature of the energy storage unit. The offset of the corresponding thresholds can be predetermined (e.g., under laboratory conditions). As an example, the offset can be retrieved from a database (e.g., a lookup table). Alternatively or additionally, the measured impedance or resistance value can be corrected based on the SoC and / or temperature of the energy storage unit.

[0056] Multiple impedance values ​​may include at least three impedance values. Furthermore, determining whether the energy storage unit 11 is suitable for further use in the aerosol generating device 10 can be based on a reconstructed electrochemical impedance spectroscopy obtained by fitting a mathematical function representing a curve in a complex plane to these at least three impedance values. Electrochemical impedance spectroscopy (EIS) is a technique involving measuring the impedance of an electrochemical system at different frequencies and is widely used in fields such as energy storage systems, biomedical systems, and corrosion research.

[0057] Figure 4 Multiple reconstructed electrochemical impedance spectra (see curves) for multiple energy storage units are shown, which are fitted to multiple measurement points (see small dots on the corresponding curves). It can be observed that for most reconstructed electrochemical impedance spectra, it is sufficient to measure the impedance value at each of at least three independently spaced frequencies of the periodically varying current (i.e., three measurement points, see three large dots). In other words, the electrochemical impedance spectrum of the energy storage unit can be reconstructed with a certain accuracy based on fitting at least three impedance values ​​corresponding to three independently spaced frequencies of the periodically varying current applied to the energy storage unit, thereby determining the degree of degradation of the energy storage unit. In this way, the electrochemical impedance spectrum of the energy storage unit 11 can be reconstructed with a certain accuracy while minimizing computational resource and time requirements. In fact, the inventors have recognized that by selecting at least two (preferably three) independently spaced frequency values, a diagnosis of the storage unit can be obtained with relatively low computational resource usage and / or in a relatively short time.

[0058] These multiple impedance values ​​can include a third frequency between 50 Hz and 1 kHz. As an example, the first frequency could be 10 Hz, the second frequency could be 1 kHz, and the third frequency could be 100 Hz. In fact, the inventors have found that these values ​​can provide favorable accuracy for diagnosis with relatively low computational resource usage and / or in a relatively short time.

[0059] The multiple impedance values ​​can include up to five impedance values. Compared to the case where multiple impedance values ​​include only three impedance values, the electrochemical impedance spectrum of the energy storage unit 11 can be reconstructed with higher accuracy while maintaining lower computational resource and time requirements. Therefore, accuracy can still be improved while balancing the computational resources and / or time required for diagnostics.

[0060] Mathematical functions can correspond to semicircles in the complex plane. Figure 5 A Nyquist plot showing an idealized electrochemical impedance spectrum including semicircle 102 (see thick line) is shown. Semicircle 102 is located in the first quadrant (real and imaginary values ​​are positive) and includes a first zero-crossing point 108 and a second zero-crossing point 110 that intersect or terminate at the real axis. Semicircle 102 can be determined based on fitting at least three impedance values ​​(measurement points).

[0061] In the case where the energy storage unit 11 is provided as a lithium-ion battery... Figure 6 A schematic representation of lithium-ion mass transfer phenomena occurring in lithium-ion battery electrodes and the corresponding Nyquist plots of these lithium-ion mass transfer phenomena are shown. Figure 6 This is excerpted from reference [1], and its detailed description can be found in section 2.5 of reference [1]. In particular, Figure 6 It shows the relationship between the frequency range and the corresponding part of the Nyquist plot.

[0062] Reconstructing the electrochemical impedance spectroscopy can indicate electrolyte resistance, charge transfer resistance, and interfacial capacitance. Furthermore, determining whether the energy storage unit 11 is suitable for further use in the aerosol generation device 10 can be based on whether one or more of the electrolyte resistance, charge transfer resistance, and interfacial capacitance exceed a corresponding threshold.

[0063] Electrolyte resistance can also be called solution resistance R. sol It can be defined as the distance between the origin and the first zero-crossing point 108, such as Figure 5 As shown. When the energy storage unit is provided as a battery, the solution resistance R sol It can indicate the resistance value from the solution (i.e., electrolyte) in the battery. Charge transfer resistance R ct It can be defined as the distance between the first zero-crossing point 108 and the second zero-crossing point 110. When the energy storage unit is provided as a battery, the charge transfer resistance R... ct It can indicate the presence of charged ions (e.g., Li). + The resistance value associated with the rate of reaction occurring at the electrode. Interface capacitance C. if (Also known as double-layer capacitor C) dl() is defined by Equation 1, where the frequency f corresponds to the frequency associated with the impedance value Z at the highest point 112 of the semicircle, and where |Z''| represents the amplitude of the imaginary part Z'' of the impedance value Z.

[0064]

[0065] [Equation 1]

[0066] Figure 7 The charge transfer resistance R of the energy storage unit is shown. cf An exemplary evolution relative to its charge / cycle count. It can be observed that the charge transfer resistance R... cf This increases relative to the number of charge / cycle cycles. Here, this can be achieved by adjusting the charge transfer resistor R. cf The degree of degradation is obtained by comparing it with a corresponding threshold. Figure 6 In the example, because the charge transfer resistance R cf The threshold value was exceeded, therefore it can be determined that the energy storage unit 11 is unsuitable for further use in the aerosol generating device 10. Those skilled in the art will understand that, based on the solution resistance R... sol and / or interface capacitance C if The determination can be made in a corresponding manner. Therefore, its description is omitted.

[0067] Among the parameters measured by EIS, the charge transfer resistance R ct and interface capacitance C if It is particularly effective at reflecting the degree of degradation. As mentioned above, the charge transfer resistance R ct The measurement requires a first zero-crossing point 108 and a second zero-crossing point 110, while the interface capacitance C if The measurement requires the highest point 112. Therefore, it is preferable to set the frequencies of the multiple impedance values ​​such that the first zero-crossing point 108 and the second zero-crossing point 110, and / or the highest point 112 can be found.

[0068] When only two impedance values ​​are used as the multiple impedance values, the first impedance value measured at high frequencies corresponds to the second zero-crossing point 110, while the second impedance value measured at low frequencies corresponds to the first zero-crossing point 108. It is known that the first zero-crossing point 108 can be measured when a frequency between 1 kHz and 50 kHz is applied, while the second zero-crossing point 110 can be measured when a frequency between 0.1 Hz and 50 Hz is applied. Therefore, the low frequency range can be between 0.1 Hz and 50 Hz, and the high frequency range can be between 1 kHz and 50 kHz. Even if the imaginary parts of the first and second impedance values ​​are not equal to zero, their amplitudes will be close to zero. Therefore, the real parts of the first and second impedance values ​​can be considered as the second zero-crossing point 110 and the first zero-crossing point 108. If the imaginary parts of the first and second impedance values ​​are sufficiently small, the charge transfer resistance value R can be measured accurately. ct Therefore, it is possible to base the charge transfer resistance value R on... ct To determine the degree of degradation of energy storage unit 11, as referenced Figure 5 Alternatively, the degree of degradation of the energy storage unit 11 can be determined based on low-frequency and high-frequency resistance values, as described above. Figure 3A and Figure 3B As stated above.

[0069] When a third frequency is used in addition to the low and high frequencies mentioned above, this third frequency can preferably be set such that the third impedance value measured at the third frequency corresponds to the highest point 112. It is known that the highest point 112 can be measured when a frequency of approximately 100 Hz is applied. Therefore, the third frequency can be 100 Hz.

[0070] In this way, the third impedance value is not only beneficial for directly measuring the interfacial capacitance C if Furthermore, it is beneficial to indirectly improve the charge transfer resistance R. ct The accuracy of the fitting is improved. The third impedance value can correspond to or be close to the highest point 112, allowing the semicircle to be fitted based on these three impedance values. By combining the first and second impedance values, the fitted semicircle can be helpful in finding the first zero-crossing point 108 and the second zero-crossing point 110.

[0071] Note that before the energy storage unit 11 is used for the first time (i.e., when the number of charge / discharge cycles is zero), the low-frequency resistor R... LF (See) Figure 3A and charge transfer resistance R ct (See) Figure 7Resistance values, such as those of the energy storage unit 11, may exhibit relatively large initial values, which then quickly stabilize at relatively low values. Therefore, the determination of whether the energy storage unit 11 is suitable for further use can be adjusted. As an example, this determination can be adjusted to discard the impedance value measured when the number of charge / discharge cycles is zero. As another example, this determination can be adjusted by increasing the corresponding threshold to be equal to or greater than the impedance value measured when the number of charge / discharge cycles is zero.

[0072] In another embodiment, a computer program (product) is provided, wherein the computer program (product) includes instructions that, when executed by a computer, cause the computer to perform any of the steps of the method described above. Figure 8 The image shows a computer according to this embodiment. Specifically, Figure 8 A computer 300 is shown, comprising a processor 320, an interface (IF) 310, and a memory 330. The interface 310 is capable of receiving information from external devices (e.g., via a USB port) and / or power supply. The memory 330 is capable of storing information in a temporary (volatile) manner and / or storing non-volatile information. For example, instructions can be stored in memory. The processor is capable of executing these instructions. The computer can be implemented as a local entity or in a distributed manner across multiple interacting entities.

[0073] The methods disclosed above will be applied accordingly to aerosol generating devices, and vice versa. While various embodiments of this disclosure have been described above, it should be understood that these embodiments are presented by way of example and not limitation. Those skilled in the art will appreciate that various changes in form and detail can be made therein. Therefore, the exemplary embodiments described above are not limiting.

[0074] Figure Labels

[0075] 10 Aerosol Generating Device

[0076] 11 Energy Storage Unit

[0077] 12 Inverter Units

[0078] 13 Control Unit

[0079] 14 Heating compartment

[0080] 15 Heating elements

[0081] 20 Aerosol-generating products

[0082] 21. Aerosol Generating Materials

[0083] 22 suction nozzle

[0084] References

[0085] [1]: Vyroubal, Petr and Tomá Kazda, “Equivalent circuit model parameters extraction for lithium ion batteries using electrochemical impedance spectroscopy”, Journal of Energy Storage, 15 (2018): 23-31.

Claims

1. A method for diagnosing the energy storage unit of an aerosol generating device, the method comprising: A periodically varying current is applied to the energy storage unit; Multiple impedance values ​​of the energy storage unit are measured, wherein each impedance value is measured at one of a set of independently spaced frequencies of the periodically changing current; as well as Based on these multiple impedance values, it is determined whether the energy storage unit is suitable for further use in the aerosol generating device.

2. The method according to claim 1, wherein, Measuring each impedance value involves controlling the periodically varying current to have the corresponding frequency from the set of independently spaced frequencies.

3. The method according to any one of claims 1 to 2, wherein, These multiple impedance values ​​include: The first impedance value of the energy storage unit measured at the first frequency of the periodically changing current; The second impedance value of the energy storage unit measured at the second frequency of the periodically changing current; The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the first impedance value and the second impedance value are greater than a corresponding threshold; and The ratio of the second frequency to the first frequency is between 20 and 500,000.

4. The method according to claim 3, wherein, The first frequency is between 0.1 Hz and 50 Hz, and / or the second frequency is between 1 kHz and 50 kHz.

5. The method according to any one of claims 3 to 4, wherein, Each of these corresponding thresholds is based on one or more of the state of charge (SoC) of the energy storage unit and the temperature of the energy storage unit.

6. The method according to any one of claims 1 to 5, in, The plurality of impedance values ​​includes at least three impedance values, and The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on the reconstructed electrochemical impedance spectroscopy obtained by fitting a mathematical function representing a curve in a complex plane to the at least three impedance values.

7. The method according to claim 6, wherein, The third frequency is between 50 Hz and 1 kHz.

8. The method according to any one of claims 6 to 7, wherein, The multiple impedance values ​​include up to five impedance values.

9. The method according to any one of claims 6 to 8, wherein, This mathematical function corresponds to a semicircle in the complex plane.

10. The method according to any one of claims 6 to 9, in, The reconstructed electrochemical impedance spectroscopy indicates electrolyte resistance, charge transfer resistance, and interfacial capacitance, and The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the electrolyte resistance, the charge transfer resistance, and the interface capacitance are greater than the corresponding threshold.

11. An aerosol generating device, comprising: Energy storage unit; An inverter unit configured to generate a periodically varying current applied to the energy storage unit; as well as Control unit, which is configured to: Multiple impedance values ​​of the energy storage unit are measured, wherein each impedance value is measured at one of a set of independently spaced frequencies of the periodically changing current; as well as Based on these multiple impedance values, it is determined whether the energy storage unit is suitable for further use in the aerosol generating device.

12. The aerosol generating apparatus according to claim 11, wherein, The control unit is configured to measure each impedance value by controlling the periodically varying current to have the corresponding frequency in the set of independently spaced frequencies.

13. The aerosol generating apparatus according to claim 11 or 12, wherein, These multiple impedance values ​​include: The first impedance value of the energy storage unit measured at the first frequency of the periodically changing current; The second impedance value of the energy storage unit measured at the second frequency of the periodically changing current; The determination of whether the energy storage unit is suitable for further use in the aerosol generating device is based on whether one or more of the first impedance value and the second impedance value are greater than a corresponding threshold; and The ratio of the second frequency to the first frequency is between 20 and 500,000.

14. The aerosol generating apparatus according to any one of claims 11 to 13, wherein, The first frequency is between 0.1 Hz and 50 Hz, and / or the second frequency is between 1 kHz and 50 kHz.

15. A computer program comprising instructions that, when executed by a computer, cause the computer to perform the method as claimed in any one of claims 1 to 10.

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