Method for monitoring aerosol-generating articles and aerosol-generating system

Abstract

A method for monitoring an aerosol-generating article (1) is described. The article (1) includes a capacitor (6). The capacitor (6) includes an electrolyte that, when heated, generates an aerosol for a user to inhale, a pair of electrodes, and a porous separator between the electrodes. The method includes estimating or determining the amount of electrolyte by applying an alternating current (AC) signal to one of the pair of electrodes (16).

Description

[Technical Field]

[0001] The present disclosure relates generally to methods of monitoring aerosol-generating articles, and more particularly to aerosol-generating articles adapted to be received in an aerosol-generating device to generate an aerosol for inhalation by a user.

[0002] As part of the aerosol generating system of the present disclosure, the aerosol-generating article may be received in an aerosol generating device that includes a controller adapted to carry out the present method. The present disclosure is particularly applicable to portable aerosol generating devices. [Background technology]

[0003] In recent years, devices that heat, rather than burn, aerosol-generating materials to generate an aerosol for inhalation have become popular with consumers. A commonly available risk-reducing or risk-modifying device is the substrate-heated aerosol-generating device, or so-called heat-and-burn device. This type of device generates an aerosol or vapor by heating the aerosol-generating material to a temperature typically in the range of 150°C to 300°C. This temperature range is significantly lower than that of a typical cigarette. Heating the aerosol-generating material to a temperature within this range, without burning or combusting the aerosol-generating material, generates a vapor that typically cools and condenses to form an aerosol for inhalation by the device user.

[0004] Such devices may provide heat to the aerosol-generating material using one of several different methods. All methods for heating the aerosol-generating material require some type of power source, such as a battery, which increases the size and weight of the device. Embodiments of the present disclosure seek to provide a power source in the aerosol-generating article that can be used to supplement or partially replace the device's power source. This may result in a smaller, lighter device, beneficial to the user, while maintaining precise control over the heating of the aerosol-generating material and optimizing the properties of the generated aerosol. Summary of the Invention [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a method for monitoring an aerosol-generating article comprising: an electrolyte that, when heated, generates an aerosol for inhalation by a user (i.e., the electrolyte is aerosolizable); A pair of electrodes; a porous separator between the electrodes; Including, The method involves estimating or determining the amount of electrolyte by applying an alternating current (AC) signal to one of a pair of electrodes.

[0006] The capacitor may have any suitable structure, but in a preferred embodiment is a supercapacitor, such as an electric double layer supercapacitor, the large capacitance of which may result in increased efficiency of aerosol generation during discharge and charging.

[0007] The pair of electrodes typically includes a positive electrode and a negative electrode. An AC signal can be applied across the positive electrode and the negative electrode. The electrodes and separator are immersed in an electrolyte.

[0008] Charge is stored in the electric field between the electrodes, and capacitance is a function of the surface area of ​​the electrodes, the distance between the electrodes, and the dielectric constant of the separator material. Capacitors have a higher power density than conventional power sources such as batteries. When a capacitor is charged by an external circuit connected to a pair of electrodes, positive ions in the electrolyte migrate toward the negative electrode and negative ions migrate to the positive electrode, while electrons migrate from the negative electrode to the positive electrode through the external circuit. Thus, two charge layers of opposite polarity (electric double layers) are formed at the interface between the electrodes. When charging is terminated, the positive charge on the positive electrode and the negative ions in the electrolyte attract each other, while the negative charge on the negative electrode and the positive ions in the electrolyte attract each other to stabilize the double layer on the electrodes, generating a stable voltage. When the capacitor is discharged, the reverse process occurs.

[0009] Each electrode may comprise at least one carbon-based electrode layer, for example a layer of porous carbonaceous material or activated carbon, which has a large specific surface area per volume and is highly compatible with the proposed electrolyte.

[0010] Each electrode may further comprise a current collector, which may include a metal foil layer, for example, an aluminum foil layer. Each current collector may facilitate the transfer of electrons through an external circuit. The carbon-based electrode layer may be disposed adjacent to one or both sides of the current collector. Each carbon-based electrode layer may be formed as a coating. Such electrodes may be relatively easy and inexpensive to manufacture using materials already known for use in aerosol-generating articles. Each current collector may facilitate the transfer of electrons through an external circuit.

[0011] As will be understood by those skilled in the art, the electrolyte serves two functions. First, it allows the movement of positive and negative ions that occur when the capacitor is charged or discharged. Second, when heated, the electrolyte forms an aerosol that is safe for the user to inhale and has good properties. Therefore, the electrolyte should be selected accordingly. The electrolyte is an aerosolizable electrolyte, i.e., it can be converted into an aerosol by heating, which is then inhaled by the user. Thus, by heating the capacitor, the electrolyte contained within the capacitor is converted into an aerosol, and the aerosolized electrolyte is then inhaled by the user. The electrolyte is preferably a food-grade electrolyte and may include, for example, one or more of sodium chloride, sodium citrate, sodium bicarbonate, potassium chloride, calcium lactate, calcium carbonate, tricalcium phosphate, magnesium citrate, magnesium carbonate, citric acid, tartaric acid, benzoic acid, glycerol, and any suitable equivalents. The electrolyte may optionally include a gelling agent, such as polyvinyl alcohol, gellan gum, or xanthan gum. In one example, the electrolyte may include sodium chloride and glycerol, and optionally polyvinyl alcohol as a gelling agent. Such electrolytes have been found to allow for the movement of cations and anions, and are also safe for users to inhale.

[0012] Once all the electrolyte has evaporated, the capacitor may no longer be able to discharge or charge, and the item may need to be properly disposed of or refilled with electrolyte.

[0013] The separator should provide dielectric separation between a pair of oppositely charged electrodes. The separator also stores an electrolyte within its pores, allowing the passage of positive and negative ions during the charge and discharge process. The separator may comprise any suitable material. The separator may comprise a plant-derived material, particularly a tobacco material, such as a porous tobacco sheet, or any suitable cellulose- or polypropylene-based material. When heated, the separator material may release one or more volatile compounds. The volatile compounds may include nicotine or flavor compounds such as tobacco or other flavorings.

[0014] The aerosol-generating article may further include any type of solid or semi-solid material downstream of the capacitor in the aerosol flow path. Exemplary types of solid or semi-solid material include crumbs, powders, granules, pellets, strips, strands, particles, gels, strips, loose-leaf, cut filler, porous materials, foam materials, or sheets. The material may include plant-derived materials, particularly tobacco materials. The aerosol generated by heating the capacitor's electrolyte flows through the solid or semi-solid material, which may be disposed between the capacitor and, for example, a filter segment or mouthpiece through which the user inhales the aerosol. The solid or semi-solid material may release one or more volatile compounds that may, for example, add flavor and nicotine to the aerosol. Any heating provided by the capacitor may also heat or warm the solid or semi-solid material, thereby facilitating the release of the volatile compounds.

[0015] The aerosol inhaled by the user consists essentially of evaporated or aerosolized electrolyte and, optionally, one or more volatile compounds that may be released by the separator material and / or downstream solid or semi-solid materials.

[0016] The capacitor may have any suitable structure, such as, for example, a spirally wound (or "jelly roll") structure, a prismatic structure, a folded or zigzag structure, or a laminated structure that may be generally cylindrical or flattened to have a more rectangular shape that may be more suitable for a flat-format article.

[0017] In one embodiment, a layered capacitor substrate may include a first electrode, a separator adjacent to the first electrode, and a second electrode adjacent to the separator, i.e., the separator is sandwiched between the first and second electrodes, particularly a pair of carbon-based electrode layers. The first electrode may be a positive electrode and the second electrode may be a negative electrode, or vice versa. Such a substrate may be rolled or folded into a suitable shape while maintaining an air gap or other dielectric separation between opposing electrodes or different portions of the same electrode. In addition to that provided by the separator, dielectric separation may be provided, for example, by one or more layers of dielectric material. The dielectric material may include any suitable material. The dielectric material may include plant-derived materials, particularly tobacco materials, such as porous tobacco sheets, or any suitable cellulose- or polypropylene-based material. When heated, the dielectric material may release one or more volatile compounds. The volatile compounds may include nicotine or flavor compounds such as tobacco or other flavorings. The dielectric material and the separator material can be the same or different.

[0018] In another embodiment, a layered capacitor substrate can include a first electrode, a first separator adjacent to the first electrode, and a second electrode adjacent to the first separator, i.e., the first separator is sandwiched between the first and second electrodes, more specifically, between a pair of carbon-based electrode layers, and the second separator is adjacent to the second electrode. The second electrode is sandwiched between the first and second separators. The first electrode can be a positive electrode and the second electrode can be a negative electrode, or vice versa. Such substrates are particularly suitable for spirally wound (or "jelly roll") structures, which can be generally cylindrical or flattened to have a more rectangular shape. Dielectric isolation between turns of a spirally wound capacitor is provided by a second separator, which can be sandwiched between the first and second electrodes, specifically, between a pair of carbon-based electrode layers, in the wound substrate.

[0019] In yet another configuration, a layered capacitor substrate can include a plurality of first electrodes, a plurality of second electrodes, and a plurality of separators. The first electrode can be a positive electrode and the second electrode can be a negative electrode, or vice versa. The first and second electrodes are alternately stacked in the stacking direction, such that the substrate includes the first electrode, the second electrode, the first electrode, the second electrode, etc. A separator is sandwiched between each pair of electrodes, more specifically, between a pair of carbon-based electrode layers, to provide dielectric isolation. Such a substrate can be useful in a flat-format article. The first electrodes can be electrically connected together, and the second electrodes can be electrically connected together. The first electrodes can be electrically connected to a first capacitor terminal, and the second electrodes can be electrically connected to a second capacitor terminal.

[0020] The capacitor may be housed in a casing. More specifically, the casing may house the capacitor substrate, including electrodes, separators, etc., and the electrolyte. The electrolyte may be injected into the casing during manufacturing or when the capacitor needs to be refilled. The casing may electrically insulate the capacitor and may be formed from any suitable material.

[0021] The casing may include, for example, a paper wrapper with a metal or polymer coating. The casing may include a pair of end caps made of any suitable material. The casing may include suitable perforations or openings or incorporate a suitable aerosol-permeable membrane material, so that the aerosol generated when the electrolyte is heated can be freely inhaled by the user while also preventing leakage of the electrolyte when in a liquid or gel state. The aerosol-generating article may include a filter segment, for example, comprising cellulose acetate fibers, at the proximal end of the aerosol-generating article. The filter segment may constitute a mouthpiece filter. One or more vapor collection regions, cooling regions, and other structures may also be included in some designs. The vapor cooling region may advantageously allow the vapor to cool and condense to form an aerosol with properties suitable for inhalation by a user, for example, through the filter segment. Generally, a vapor is a substance that is in the gas phase below a critical temperature, meaning that the vapor can be condensed into a liquid by increasing the pressure without decreasing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets in air or other gas. However, it should be noted that the terms "aerosol" and "vapor" may be used interchangeably herein.

[0022] The capacitor is preferably pre-charged in the packaged article, i.e., already charged at the time of purchase by the user and before being removably inserted into the aerosol generating device. Pre-charging the capacitor reduces the amount of energy required from the device's power source for heating, which may result in a reduction in the size and weight of the device.

[0023] The aerosol generating device may be adapted to receive an aerosol-generating article during use, as described above. The aerosol generating device may include an external circuit (e.g., a switching circuit) electrically connected between a pair of electrodes or capacitor terminals when the article is received in the device. Heating of the electrolyte may be controlled by controlling the discharging and, optionally, the charging of the capacitor, i.e., when the capacitor is cycled between discharging and charging. In particular, the switching circuit may include a switching device that may be controlled by a controller to selectively provide a continuous or switched (i.e., discontinuous or intermittent) short-circuit path between the pair of electrodes or capacitor terminals, allowing the charge stored in the capacitor to be discharged through the switching circuit. The switching device may also be controlled by the controller to charge the capacitor from a power source, which may optionally include a suitable power converter, such as a bidirectional power converter, that provides a suitable direct current (DC) output voltage. The switching device may include one or more switches. For example, the switching device may include a discharge switch that may be switched on to provide a short-circuit path between the pair of electrodes or capacitor terminals to discharge the capacitor, and a charge switch that may be switched on to charge the capacitor. Each switch may be a controllable semiconductor switch, such as a transistor (e.g., a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), or a bipolar transistor). One or more switches may be opened or closed, or switched on and off, by a controller.

[0024] The switching circuit may include a first terminal electrically connected to a first electrode or terminal of the capacitor when the aerosol-generating article is received in the device, and a second terminal electrically connected to a second electrode or terminal of the capacitor. To prevent accidental or intentional discharge of a pre-charged capacitor before the article is inserted into the device, at least one of the capacitor's electrodes or terminals is preferably inaccessible to the user. For example, one or both of the capacitor's electrodes or terminals may be concealed within the casing of the article and made accessible for electrical connection with the terminal of the switching circuit only after the aerosol-generating article has been inserted into the device or is in the process of being inserted. Electrical connection may require the casing to be broken at one or more locations, and the device may include appropriate means for breaking, puncturing, or rupturing the casing. The first terminal of the switching circuit may be electrically connected directly to the first electrode at one or more locations, or may be electrically connected to a first capacitor terminal that is in turn electrically connected to the first electrode. Similarly, the second terminal of the switching circuit may be electrically connected directly to the second electrode at one or more locations, or may be electrically connected to a second capacitor terminal that is in turn electrically connected to the second electrode. The capacitor terminal may be located anywhere on the article, such as near an end cap or side of the article. The insertion orientation of the aerosol-generating article into the device may be restricted to ensure precise alignment between the respective terminals to provide a reliable electrical connection between the capacitor and the external switching circuit.

[0025] The terminals of the switching circuit may be formed as a breaking device designed to break, perforate, or tear the casing to create an electrical connection with the electrodes or terminals of the capacitor. The breaking device may be fixed to or stationary relative to the device and designed to break, perforate, or tear the casing when an item is inserted into the device, for example, into the aerosol-generation space or heating chamber. The breaking device may also be movable. For example, in one configuration, the breaking device may be attached to a panel or door of the device that is opened or removed to allow an item to be inserted, and the breaking device is designed to break, perforate, or tear the casing when a user closes the panel or door. The panel or door may be hinged, for example. In another configuration, the breaking device may be moved by a suitable actuator, such as an electric motor or piston, that can force the breaking device to move within the casing to create an electrical connection. The breaking device may be moved through an opening or slot in a portion of the device that defines the aerosol-generation space or heating chamber. The breaking device may have any suitable shape, for example, a needle or crown shape with one or more sharp points, a blade shape with an edge, or a punch shape with a blunt point. The breaking device may be designed to work with any of the capacitor structures described above. If one of the electrodes or terminals of the capacitor is accessible, only one breaking device may be required.

[0026] Discharging a pre-charged capacitor through an external circuit, such as the device's switching circuit, generates heat within the electrodes, which in turn heats the electrolyte in which the electrodes are immersed. Sufficiently heating the electrolyte generates the aerosol that the user inhales during a vaping session. To improve heating, the internal resistance of the capacitor can be increased by increasing the thickness of the separator between the oppositely charged electrodes. As a result, the capacitor can be wound or folded less if the overall dimensions remain the same. Using an external circuit to charge the capacitor also generates heat within the electrodes, which then heats the electrolyte and generates the aerosol that is inhaled.

[0027] The device may also include an external heater for heating the capacitor to generate an aerosol for inhalation by the user. In other words, heating of the electrolyte is not limited to the heat generated by the capacitor when it is discharged or charged, but the capacitor may be heated by an external heater in a manner similar to that of conventional aerosol-generating materials or substrates. Such heating heats the electrolyte to generate an inhaled aerosol. The use of an external heater may provide more controllable heating during specific phases of a vaping session, thereby optimizing the user's experience. Any suitable heater may be used, such as a low-power thin-film heater, a printed heater, or the like. However, an induction heater may be preferred. The induction heater may include an induction coil and a susceptor and may be configured to heat the capacitor. For example, the induction coil may be positioned adjacent to the aerosol-generation space or heating chamber of the aerosol-generating device, which is designed to receive the aerosol-generating article (or consumable). When the induction heater is used to heat the electrolyte, an alternating current electromagnetic field is generated by the induction coil. The susceptor in the aerosol-generating article couples with this electromagnetic field and generates heat due to eddy currents and / or magnetic hysteresis, which is then transferred from the susceptor to the electrolyte. To generate the AC electromagnetic field required for induction heating, the device may further include an inverter electrically connected to the induction coil. The same inverter may also be used to generate an AC signal applied across the electrodes or terminals of the capacitor to estimate or determine the amount of electrolyte in the capacitor. In particular, the inverter may be selectively connected to one or both of the capacitor and the induction coil of the induction heater, for example, by a suitable switching device. The susceptor of the induction heater preferably includes a current collector of the capacitor electrode. In other words, the current collector may also function as a susceptor for the induction heater and transfer heat to the electrolyte when the induction heater is operated. Because the current collector has at least two functions, the size and weight of the aerosol-generating system may be reduced. In particular, the aerosol-generating article does not need to include one or more separate susceptors for heating the electrolyte when the induction heater is operated.

[0028] Heat generated by discharging the capacitor or by cycling the capacitor between charging and discharging can be used during an initial pre-heating phase, and an external heater can be used, for example, to heat the electrolyte and generate the aerosol during a subsequent heating or vaping phase. Power for pre-heating can therefore be provided at least in part by the capacitor rather than by the device's power supply. This can result in a smaller power supply and therefore a smaller and lighter device. Alternatively, the electrolyte can be heated during a subsequent heating or vaping phase by repeated charging and discharging of the capacitor. During the heating or vaping phase, there can be times when heating is not required and therefore the capacitor does not need to be discharged or charged. When heating is required, the capacitor can be continuously discharged or charged, or intermittently discharged or charged, for example, with an appropriate duty cycle.

[0029] The pre-heating phase may generally be intended to pre-heat the electrolyte to a target temperature, and the heating or vaping phase may generally be intended to heat the electrolyte for a longer period during which the aerosol is generated, and the temperature may be controlled, for example, according to a temperature profile.

[0030] The method according to the first aspect of the present disclosure may further include notifying the user of the amount of electrolyte. The amount of electrolyte may be notified visually or in any other manner, such as by using an audio or tactile notification. The amount of electrolyte may be displayed to the user using a visual indicator or as a numerical value, such as a percentage, where a value of 100% indicates the maximum amount of electrolyte, i.e., the capacitor is filled with electrolyte. The article or device may include a visual display for displaying the amount of electrolyte to the user. The visual display may be, for example, an LED display. The amount of electrolyte may be notified to the user using an external device, such as a smartphone, connected to the device by an appropriate wireless communication protocol. If the amount of electrolyte falls below a certain amount, a message may be notified to the user. The message may be notified visually or in any other manner.

[0031] By monitoring the amount of electrolyte and notifying the user, the user is better informed of the amount of electrolyte remaining in the capacitor over the course of a vaping session and can therefore calculate how much aerosol a particular aerosol-generating article will continue to generate. The user can also better understand how long an unused aerosol-generating article may last before the electrolyte is consumed and / or how many aerosol-generating articles the user may need over a particular period of time.

[0032] The amount of electrolyte may be estimated or determined using one or more electrical parameters of the capacitor. For example, the amount of electrolyte may be estimated or determined using a function, such as a linear or polynomial function, optionally implemented as a look-up table, relating the amount of electrolyte to one or more electrical parameters. The one or more electrical parameters of the capacitor may be estimated or determined using voltage and current measurements obtained in response to the AC signal applied during the electrolyte amount detection step.

[0033] The one or more electrical parameters of the capacitor are known to vary with the amount of electrolyte, such as internal resistance and capacitance. The electrical parameter may also be, for example, a time constant associated with capacitance and / or internal resistance. These parameters are directly proportional to the surface contact area between the electrolyte and the capacitor's electrodes and therefore vary as the amount of electrolyte decreases over the course of a vaping session. The one or more electrical parameters may be estimated or determined based on the frequency dependence of the capacitor's dielectric material. The capacitance and / or internal resistance of the capacitor may be estimated or determined with reference to a frequency response plot, such as a Nyquist plot (or Cole-Cole plot). The frequency of the applied AC signal is swept as a parameter, resulting in a plot based on frequency. This is described in more detail below with reference to FIG. 8, which shows an example of a Nyquist plot and an equivalent electrical circuit of a capacitor. The equivalent electrical circuit may include the interfacial capacitance C, which appears as a diagonal line with a 45-degree slope on the Nyquist plot. if , solution resistance (or ohmic internal resistance) R sol , charge transfer resistance R ct , and the diffusion resistance (or Warburg resistance) Z w Includes:

[0034] The applied AC signal may have a frequency within a preferred frequency range. For example, the frequency range may be from about 1 mHz to about 1 kHz. A wider frequency range may be beneficial because it may enable more accurate measurement of capacitance, but it may also increase measurement duration. The preferred frequency range may be a compromise between these competing factors. The frequency may be swept across substantially the entire frequency range or across one or more narrower frequency ranges. For example, a frequency response plot may be constructed by focusing on one or more narrower frequency ranges, such as a first frequency range of about 500 Hz to about 1 kHz (which may provide an indication of solution resistance), a second frequency range of about 1 Hz to about 100 Hz (which may provide an indication of charge transfer resistance), and by focusing on the semicircular portion of the Nyquist plot shown in FIG. 8 and a third frequency range below about 1 Hz (which may provide an indication of diffusion resistance). The frequency of the applied AC signal may be swept across the preferred frequency range one or more times. Alternatively, two or more preferred frequencies may be used, for example, one or more frequencies within each of the narrower frequency ranges described above. It may be preferable to use at least two frequencies within a second frequency range (i.e., about 1 Hz to about 100 Hz) to improve accuracy. As will be appreciated by those skilled in the art, measurements at one or more preferred frequencies may be used to construct a simplified frequency response plot, e.g., a Nyquist plot that omits diffusion resistance. Different frequencies may be used during the course of a vaping session; for example, during the heating or vaping phase, frequencies at the upper end of the range may be preferred because they may provide faster determinations.

[0035] The capacitance C of a capacitor can be estimated or determined from the following formula:

number

[0036] The imaginary part of the complex capacitance C''(ω) is directly proportional to the internal resistance of the capacitor and can be estimated or determined from the following equation:

number

[0037] In conventional capacitors, the electrolyte is contained within a sealed casing, so the amount of electrolyte remains constant. However, in articles according to the present disclosure, the electrolyte is inhaled as an aerosol by the user over the course of a vaping session, so the amount of electrolyte gradually decreases. Therefore, one or more electrical parameters of the capacitor will also change during the vaping session as the amount of electrolyte decreases. Other factors, such as the temperature of the capacitor, can also affect how one or more electrical parameters of the capacitor change and therefore can be taken into account when the one or more electrical parameters are used to estimate or determine the amount of electrolyte.

[0038] One or more electrical parameters of the capacitor may be estimated or determined using at least one of voltage or current measurements obtained when an AC signal is applied to the electrodes or capacitor terminals. For example, the voltage and current measurements may be obtained from voltage and current sensors.

[0039] A capacitor can be operated in a heating mode when it is being charged or discharged to intentionally heat the electrolyte and generate an aerosol for the user to inhale. In other words, during a vaping session, the capacitor will operate in a heating mode when it is necessary to heat the electrolyte. During the heating mode, a DC current is applied to the capacitor to charge it, or a DC current is discharged from the capacitor through a switching circuit (e.g., by providing a short-circuit path between the electrodes or terminals of the capacitor). These currents may be referred to as a DC charging current and a DC discharging current. Applying a charging DC current increases the charge stored by the capacitor. When the capacitor is discharged, the charge decreases. The discharging and / or charging of the capacitor, and therefore the heating of the electrolyte, during the heating mode can be controlled by varying the power at which the capacitor is discharged and / or charged through the switching circuit. For example, the discharge and / or charge power can be varied by controlling the switching devices of the switching circuit so that the capacitor is intermittently discharged or charged using an appropriate duty cycle; e.g., a charge or discharge switch of the switching device is periodically switched on and off with a duty cycle that can be varied to control the rate at which the capacitor is discharged or charged. More specifically, the time (or "pulse width") for which the charge or discharge switch is switched on can be varied. It will also be readily understood that there are times when the capacitor operates in a heating mode when the capacitor is not actually charging or discharging (i.e., when the charge or discharge switch is switched off according to a duty cycle). Nevertheless, the overall intent during the heating mode is to operate the capacitor so that the electrolyte is heated to generate an aerosol.

[0040] The AC signal applied to the capacitor has a small current value that does not significantly heat the electrolyte, and therefore is not considered when determining whether the capacitor is operating in a heating or non-heating mode.

[0041] The capacitor may also be operated in a non-heating mode when heating is not required during a vaping session, during which the capacitor is not charged or discharged.

[0042] The AC signal may be applied to the electrodes when the capacitor is in the heating mode and the non-heating mode. For example, the AC signal may be applied substantially continuously or when the amount of electrolyte is estimated or determined regardless of whether the capacitor is in the heating mode or the non-heating mode. Alternatively, the AC signal may be applied to the electrodes only when the capacitor is in the non-heating mode. This may simplify the switching circuitry, for example, because it is not necessary to superimpose the AC signal on the DC current applied to the capacitor when the capacitor is being charged. In some embodiments, for example, if the frequency of the AC signal is sufficiently high, it may be possible to apply the AC signal during the capacitor's heating mode only when the capacitor is not being charged or discharged (i.e., only when the charge or discharge switch is switched off according to the duty cycle). The AC signal would not be applied when the charge or discharge switch is switched on to charge or discharge the capacitor during the heating mode. In this case, the switching circuitry may also be simplified.

[0043] The monitoring method may include one or more electrolyte amount detection steps. More specifically, the method may include an initial step in which an initial value of one or more electrical parameters of the capacitor is estimated or determined. The initial step may be performed, for example, when the aerosol-generating article is inserted into the device or before a pre-heating phase. The initial value may be used to define a "baseline" indicating the initial amount of electrolyte in the capacitor before the start of a vaping session. The initial amount of electrolyte may be assumed to be the maximum amount (i.e., the capacitor is filled with electrolyte). Alternatively, the initial value may be used to estimate or determine the initial amount of electrolyte in the capacitor using, for example, an appropriate linear or nonlinear function or a look-up table relating the initial value to the initial amount of electrolyte. The initial amount of electrolyte may be communicated to the user. Instead of an initial value estimated or determined in the initial step, a reference value or a predetermined value may be used to define the "baseline."

[0044] The method may further include one or more subsequent steps in which subsequent values ​​of one or more electrical parameters of the capacitor are estimated or determined. For each subsequent step, the remaining amount of electrolyte in the capacitor may be estimated or determined using the initial value and each subsequent value. For example, the remaining amount of electrolyte may be estimated by comparing each subsequent value to an initial (or "baseline") value. Alternatively, for each subsequent step, the amount of electrolyte in the capacitor may be estimated or determined using only each subsequent value, relating the subsequent value to the remaining amount of electrolyte, e.g., using a suitable linear or nonlinear function, lookup table, or the like. The amount of electrolyte may be estimated or determined using explicit values ​​of one or more electrical parameters of the capacitor or using relative values ​​(i.e., a change in the value of one or more electrical parameters indicates a relative change in the amount of electrolyte). For example, it may be determined that an x% decrease in the value of one or more electrical parameters of the capacitor corresponds to a y% decrease in the amount of electrolyte.

[0045] The amount of electrolyte remaining in the capacitor may be notified to the user.

[0046] The values ​​of one or more electrical parameters and / or the amount of electrolyte estimated or determined in the initial step or any subsequent step may be used to control the operation of the device, such as varying the heating, or to prevent further use of the device if the amount of electrolyte is below a minimum amount. This ensures that the user operates the device safely. Such operation may, for example, allow the capacitor to heat until the electrolyte is substantially completely depleted, rather than limiting the number of puffs or the duration of a vaping session. This may increase user satisfaction because the user may consume all of the available electrolyte in the aerosol-generating article. The values ​​of one or more electrical parameters and / or the amount of electrolyte estimated or determined may also be used to identify defects in the article (e.g., if the initial value or initial amount of electrolyte is too low or below a certain amount).

[0047] Each subsequent step may be performed at regular or irregular intervals during a vaping session, or may be performed in response to puff detection (i.e., when the user inhales the generated aerosol). This helps the user understand how much electrolyte remains in the capacitor after a puff is taken. Each subsequent step may be performed when the temperature of the capacitor is maintained substantially constant. During the initial step or each subsequent step, the AC signal may be applied for an appropriate length of time, for example, sufficient to allow the amount of electrolyte to be estimated or determined. In some embodiments, the AC signal may be applied outside of the time during which the electrolyte amount detection step is performed.

[0048] If the amount of electrolyte estimated or determined in any subsequent step is outside an expected range (i.e., because the estimated or determined amount is too low and therefore invalid, suggesting that too much electrolyte has evaporated, or because the amount is too high and therefore suggests that not enough electrolyte has evaporated for the particular operating conditions of the aerosol generating device), the method may include notifying the user of the estimated or determined amount of electrolyte based on one or more previously estimated or determined amounts of electrolyte. The expected range may be based on a previously estimated or determined amount of electrolyte, for example, an amount estimated or determined in an immediately preceding step. If the estimated or determined amount of electrolyte is invalid, the amount of electrolyte notified to the user may be estimated using one or more previous amounts of electrolyte that were within the expected range. This may provide a more reliable notification to the user. For example, two or more previously estimated or determined amounts of electrolyte (i.e., valid amounts obtained during two or more previous steps) may be used to determine a rate of change of electrolyte, which may be applied to the previously estimated or determined amount to estimate the current amount of electrolyte in the capacitor, and then the user may be notified. The rate of change may, for example, be applied to the amount of electrolyte estimated or determined in a preceding step. The determined rate of change may be, for example, linear or non-linear.

[0049] According to a second aspect of the present disclosure, there is provided an aerosol generation system, the aerosol generation system comprising: 1. An aerosol-generating article comprising a capacitor, the capacitor comprising: an electrolyte that, when heated, generates an aerosol for inhalation by a user; A pair of electrodes; a porous separator between the electrodes; an aerosol-generating article comprising: an aerosol generating device into which the aerosol-generating article is received, the aerosol generating device further comprising a controller adapted to carry out the method described above.

[0050] According to a third aspect of the present disclosure, there is provided an aerosol generation system, the aerosol generation system comprising: 1. An aerosol-generating article comprising a capacitor, the capacitor comprising: an electrolyte that, when heated, generates an aerosol for inhalation by a user; A pair of electrodes a porous separator between the electrodes; an aerosol-generating article comprising: An aerosol-generating device into which an aerosol-generating article is received, comprising: Power supply and a switching circuit electrically connected between the pair of electrodes and configured to control discharging of the capacitor and charging of the capacitor from a power source; an inverter electrically connected to one of the pair of electrodes and configured to apply an AC signal to the electrode; and an aerosol generating device further comprising:

[0051] The capacitor can be configured to operate in a heating mode when the capacitor is being charged or discharged, and in a non-heating mode to heat the electrolyte and generate an aerosol for the user to inhale. The inverter can be configured to apply an AC signal to the electrodes when the capacitor is in the heating mode and the non-heating mode, or only when the capacitor is in the non-heating mode.

[0052] The system may further include a superposition circuit electrically connected to the inverter and the switching circuit. The superposition circuit may be configured to superpose an AC signal on the DC current provided by the power source when the capacitor is being charged, thereby allowing the amount of electrolyte to be estimated or determined when the capacitor is in a heating mode and is being charged or discharged. The superposition circuit may be omitted if the AC signal is applied only when the capacitor is in a non-heating mode (i.e., when heating of the electrolyte is not required and the capacitor is not being charged or discharged).

[0053] The system may further include an AC coupling capacitor electrically connected in series between the inverter and the superposition circuit.

[0054] The system may further include a bypass circuit electrically connected in parallel to the input and output of the superposition circuit. A discharge current for the capacitor may be supplied to the input of the superposition circuit via the bypass circuit. The bypass circuit may include a switch, e.g., a semiconductor switch such as a transistor, and a diode that provides reverse current protection. The switch may be turned on by the controller when the capacitor is being discharged during the heating mode and when an AC signal is applied to the capacitor via the superposition circuit to estimate or determine the amount of electrolyte.

[0055] The system may further include a charging switch configured to turn on and off charging of the capacitor from the power source, and a diode electrically connected between the power source and the charging switch, the diode providing reverse current protection when the discharge current flows through the bypass circuit.

[0056] The switching circuit and the inverter may be electrically connected in parallel with the capacitor.

[0057] The device may further comprise a visual display adapted to display the amount of electrolyte estimated or determined by the controller. [Brief explanation of the drawings]

[0058] [Figure 1] 1 is a schematic diagram of an example of an aerosol-generating article. [Figure 2] FIG. 1 is a schematic diagram of an example of a capacitor having a spiral winding structure. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] 1 is a schematic diagram of an aerosol generating device. [Figure 5] FIG. 1 is a circuit diagram of a first example of an electrical circuit for an aerosol generating device. [Figure 6]FIG. 1 is a circuit diagram of a second example of an electrical circuit for an aerosol generating device. [Figures 7A-7D] 7A-7C are circuit diagrams of a second example of the electrical circuit of FIG. 6, illustrating different modes of operation. [Figure 8] 1 is a circuit diagram of an example of a Nyquist plot and an equivalent electrical circuit of a capacitor; DETAILED DESCRIPTION OF THE INVENTION

[0059] Embodiments of the present disclosure will now be described, by way of example only, and with reference to the accompanying drawings, in which:

[0060] 1, there is shown a schematic representation of an example aerosol-generating article 1. The aerosol-generating article 1 has a proximal end 2 and a distal end 4.

[0061] The aerosol-generating article 1 includes a capacitor 6 containing an electrolyte. The capacitor 6 is surrounded by a paper wrapper 8 having a metal or polymer coating. End caps 10a, 10b are provided at each end of the capacitor 6. The paper wrapper 8 and the end caps 10a, 10b define an outer casing for the capacitor 6 that contains the electrolyte and provides electrical insulation.

[0062] The aerosol-generating article 1 may be generally cylindrical.

[0063] At the proximal end 2, the aerosol-generating article 1 includes a mouthpiece 12 having an outlet 14 through which a user can inhale the aerosol generated by heating the electrolyte. Although not shown, the proximal end cap 10a may include suitable perforations or openings or may incorporate a suitable aerosol-permeable membrane material to allow the generated aerosol to pass through the end cap to the outlet 14.

[0064] Referring to FIG. 2 , the capacitor 6 is an electric double layer supercapacitor having a generally cylindrical spirally wound (or “jelly roll”) structure. The capacitor 6 includes a positive electrode 16 and a negative electrode 18. The electrodes 16, 18 are separated by a pair of porous separators 20 a, 20 b. As shown more clearly in FIG. 3 , the positive electrode 16 includes a positive current collector 22. A porous carbon-based electrode layer 24, such as a layer of porous carbon material or activated carbon, is provided on each side of the positive current collector 22. The negative electrode 18 includes a negative current collector 26. A porous carbon-based electrode layer 28, such as a layer of porous carbon material or activated carbon, is provided on each side of the negative current collector 26. The positive and negative current collectors 22, 26 are, for example, aluminum foil layers. The positive and negative current collectors 22, 26 can enhance the charging and discharging of the capacitor 6.

[0065] Separators 20a, 20b are formed from tobacco material, such as a porous tobacco sheet, that releases volatile compounds when heated. In an alternative configuration not shown, the separators may be formed from a suitable cellulose or polypropylene-based material, and the electrolyte may flow through tobacco material, such as crumb tobacco, downstream of capacitor 6 in the aerosol flow path. The tobacco material may be disposed between capacitor 6 (particularly the proximal end of the capacitor) and mouthpiece 12. The tobacco material adds flavor and nicotine to the aerosol. Heat provided by the capacitor also heats or warms the tobacco material, thereby promoting the release of volatile compounds. A nicotine-free flavor source may be used instead of tobacco material. Additionally or alternatively, the tobacco material may be embedded within mouthpiece 12.

[0066] Electrodes 16, 18 and separators 20a, 20b are immersed in an electrolyte that allows for the movement of positive and negative ions as capacitor 6 is charged or discharged and, when heated, generates an aerosol for inhalation by the user. The electrolyte may include sodium chloride and glycerol, and optionally, polyvinyl alcohol as a gelling agent. Capacitor 6 is pre-charged during the manufacturing process and is packaged and sold to users in a pre-charged state.

[0067] The aerosol-generating article 1 includes a positive capacitor terminal 30 electrically connected at one or more locations to the positive electrode 16, i.e., the positive current collector 22, and a negative capacitor terminal 32 electrically connected at one or more locations to the negative electrode 18, i.e., the negative current collector 26. The capacitor terminals 30, 32 may be located inside the outer casing of the aerosol-generating article 1 so that they are not accessible to the user. This helps to prevent accidental or intentional discharge of the capacitor 6 before the article is removably inserted into the aerosol-generating device in preparation for the commencement of a vaping session.

[0068] Figure 4 shows an aerosol-generating device 34 adapted to receive an aerosol-generating article 1. The aerosol-generating device 34 includes a cavity 36 into which the aerosol-generating article 1 can be inserted.

[0069] The aerosol-generating device 34 includes a pair of breaking devices 38, 40 adapted to break the distal end cap 10b of the aerosol-generating article 1 when the aerosol-generating article 1 is inserted into the cavity 36. The angular orientation of the aerosol-generating article 1 relative to the aerosol-generating device 34 can be limited when inserted into the cavity 36 so that the breaking device 38 makes electrical connection with the positive electrode 30 and the breaking device 40 makes electrical connection with the negative electrode 32. Other methods of ensuring a reliable electrical connection can be used. For example, the positive and negative terminals 30, 32 of the aerosol-generating article 1 can have annular structures and be positioned coaxially with each other, such that properly positioned breaking devices 38, 40 will make electrical contact with the terminals regardless of the angular orientation of the aerosol-generating article 1 relative to the aerosol-generating device 34.

[0070] The aerosol generating device 34 includes an electrical circuit 42 and a power source 44, such as a battery (e.g., a lithium-ion secondary battery).

[0071] The aerosol-generating device 34 may optionally include one or more heaters. The aerosol-generating device 34 shown in Figure 4 includes an induction heater having an induction coil 46 positioned adjacent to the cavity 36 to heat the capacitor 6 when the aerosol-generating article 1 is inserted into the aerosol-generating device 34. The current collectors 22, 26 of the capacitor electrodes 16, 18 may function as a susceptor for the induction heater.

[0072] The aerosol generating device 34 includes a visual display 48 for displaying the amount of electrolyte to the user. The visual display 48 is used to display the amount of electrolyte to the user as a numerical value, more specifically as a percentage, with 100% indicating that the capacitor 6 is filled with electrolyte. Other visual displays or indicators, such as an indicator bar and / or a circle, may also be used. The amount of electrolyte may be displayed or communicated to the user using an external device, such as a smartphone, connected to the external device by an appropriate wireless communication protocol.

[0073] A first example of the electrical circuit 42A is shown in Figure 5. The electrical circuit 42A includes a switching circuit 50, a low dropout (LDO) regulator 52, an inverter 54, and a microcontroller unit (MCU) 56.

[0074] DC / DC converter 58 is electrically connected to power supply 44 and provides charging current to capacitor 6. Note that DC / DC converter 58 may be a buck (or step-down) converter, a boost (or step-up) converter, or a buck-boost converter and may convert the DC input voltage from power supply 44 to an appropriate DC output voltage. DC / DC converter 58 may be omitted in some embodiments. DC / DC converter 58 includes a voltage input terminal (labeled “VIN”) and a voltage output terminal (labeled “VOUT”). The ground terminal (labeled “GND”) is electrically connected to ground. The voltage input terminal is electrically connected to power supply 44. DC / DC converter 58 includes a feedback terminal (labeled “FB”) that receives DC output voltage feedback. DC / DC converter 58 includes a serial data terminal (labeled “SDA”) and a serial clock terminal (labeled “SCL”) that are electrically connected to corresponding terminals of MCU 56. DC / DC converter 58 also includes an enable terminal (labeled "EN") that is electrically connected to a first input / output terminal (labeled "I / O1") of MCU 56 and that allows MCU 56 to enable and disable operation of DC / DC converter 58. In this embodiment, the enable terminal of DC / DC converter 58 functions according to positive logic, i.e., DC / DC converter 58 outputs a voltage from the voltage output terminal only when a high level signal is input to the enable terminal. It will be understood that the enable terminal may alternatively function according to negative logic.

[0075] The LDO regulator 52 is electrically connected to the power supply 44. The LDO regulator 52 includes an input terminal (labeled "IN") that is electrically connected to the power supply 44 and an output terminal (labeled "OUT") that provides a regulated power supply. The ground terminal (labeled "GND") is electrically connected to ground. The LDO regulator 52 also includes an enable terminal (labeled "EN") that is electrically connected to the power supply 44. In this embodiment, the enable terminal of the LDO regulator 52 functions according to positive logic, and the input and enable terminals of the LDO regulator 52 are electrically connected in parallel to the power supply 44. This means that the LDO regulator 52 continuously outputs a regulated voltage from its output terminal unless the power supply 44 is available.

[0076] The inverter 54 is electrically connected in parallel to the DC / DC converter 58 and the power supply 44. The inverter 54 includes a positive input terminal (labeled "IN+") electrically connected to the power supply 44 and a negative input terminal (labeled "IN-") electrically connected to ground. The inverter 54 includes a positive output terminal (labeled "OUT+") and a negative output terminal (labeled "OUT-"). The inverter 54 includes a serial data terminal (labeled "SDA") and a serial clock terminal (labeled "SCL") that are electrically connected to corresponding terminals of the MCU 56. The inverter 54 also includes an enable terminal (labeled "EN") that is electrically connected to a second input / output terminal (labeled "I / O") of the MCU 56 and that allows the MCU 56 to enable and disable the operation of the inverter 54. The enable terminal of the inverter 54 functions according to either positive or negative logic.

[0077] The switching circuit 50 includes a positive rail 60 electrically connected to the positive electrode 16 of the capacitor 6, and a ground rail 62 electrically connected to the negative electrode 18 and ground. Although not shown in FIG. 5 , it will be understood that the positive rail 60 and the ground rail 62 may be electrically connected to the capacitor 6 by a pair of breaking devices 38, 40 that form electrical connections with the positive capacitor terminal 30 and the negative capacitor terminal 32. The positive output terminal (labeled “OUT+”) of the inverter 54 is electrically connected to the positive rail 60, optionally by an AC coupling capacitor C1. The negative output terminal (labeled “OUT”) of the inverter 54 is electrically connected to the ground rail 62.

[0078] The first semiconductor switch Q1 is electrically connected between the positive rail 60 and the ground rail 62 and, when switched on, provides a short-circuit path between the positive electrode 16 and the negative electrode 18. This short-circuit path may be used to discharge the capacitor 6 and may also electrically connect the current collectors 22, 26 due to eddy currents when the external induction heater is operated to heat the capacitor 6. The discharge / short-circuit current through the first semiconductor switch Q1 is indicated by a solid arrow. The positive rail 60 is electrically connected to the output voltage terminal of the DC / DC converter 58 by a second semiconductor switch Q2. When the DC / DC converter 58 is enabled, the second semiconductor switch Q2 may be switched on to charge the capacitor 6. The charging current through the second semiconductor switch Q2 is indicated by a solid arrow. The first semiconductor switch Q1 and the second semiconductor switch Q2 may define the switching devices of the switching circuit 50.

[0079] The MCU 56 includes an input voltage terminal (labeled "VDD") electrically connected to the output voltage terminal of the LDO regulator 52 to receive the regulated power supply. As described above, the MCU 56 includes a serial data terminal (labeled "SDA") and a serial clock terminal (labeled "SCL") electrically connected to corresponding terminals of the DC / DC converter 58 and the inverter 54. The MCU 56 includes a ground terminal (labeled "GND") electrically connected to ground. As described above, the MCU 56 includes first and second input / output terminals electrically connected to the enable terminals of the DC / DC converter 58 and the inverter 54, respectively.

[0080] The voltage sensing circuit 64 is configured to detect the voltage across the capacitor 6. The voltage sensing circuit 64 includes a voltage divider.

[0081] The current sense circuit 66 is configured to detect the current flowing through the capacitor 6 and includes a shunt resistor 68 electrically connected in series with the ground rail 62 of the switching circuit 50, and a current sense amplifier 70 electrically connected with the shunt resistor 68. An additional operational amplifier 72 may be provided to improve the accuracy of the current measurement, since any stray capacitance is canceled by holding 0V at the positive terminal of the shunt resistor 68.

[0082] The MCU 56 also includes: - A third input / output terminal (labeled "I / O") electrically connected to the first semiconductor switch Q1 to switch it on and off. When the first semiconductor switch Q1 is switched on, a short circuit path is provided between the positive rail 60 and the ground rail 62, and therefore between the first electrode 16 and the second electrode 18 of the capacitor 6. This short circuit path can be used to discharge the capacitor 6 or to promote eddy currents between the current collectors 22, 26, which act as susceptors when the capacitor 6 is heated by an external induction heater. When the first semiconductor switch Q1 is switched off, there is no short circuit path through the first semiconductor switch Q1. - A fourth input / output terminal (labeled "I / O") electrically connected to the second semiconductor switch Q2 for switching it on and off. When the second semiconductor switch Q2 is switched on, the positive rail 60 is electrically connected to the output voltage terminal of the DC / DC converter 58 such that a DC current is applied to the positive electrode 16 of the capacitor 6 to charge it. When the second semiconductor switch Q2 is switched off, the positive rail 60 is electrically disconnected from the output voltage terminal of the DC / DC converter 58 and no DC current is applied to the positive electrode 16 of the capacitor 6. a fifth input / output terminal (labeled "I / O") electrically connected to the voltage sensing circuit 64 by an AC coupling capacitor C2, which may optionally form part of the voltage sensing circuit; - A sixth input / output terminal (labeled "I / O") electrically connected to the current sense amplifier 70 of the current sense circuit 66 by an AC coupling capacitor C3, which may optionally form part of the current sense circuit.

[0083] The capacitor 6 is operated in a heating mode when the electrolyte needs to be heated. In the heating mode, the capacitor 6 is discharged, charged, or cycled between discharge and charge. This generates heat within the electrodes 16, 18, which then heats the electrolyte in which the electrodes are immersed, generating an aerosol that the user can inhale through the mouthpiece 12 of the aerosol generating device 34. More specifically, in the heating mode, the capacitor 6 can be discharged by periodically switching the first semiconductor switch Q1 on and off with a duty cycle. The capacitor 6 can also be charged by enabling the DC / DC converter 58 and periodically switching the second semiconductor Q2 on and off with a duty cycle so that a charging current is applied to the capacitor. When the capacitor 6 is being discharged, the DC / DC converter 58 can be disabled. In the non-heating mode, the capacitor 6 is not charged or discharged. An AC signal is applied only across the positive and negative electrodes of the capacitor 6 during the non-heating mode. The AC signal is applied by selectively enabling the inverter 54 when the capacitor 6 is operated in the non-heating mode. In FIG. 5, the applied AC signal is indicated by the dashed arrow.

[0084] A second example of electrical circuit 42B is shown in Figure 6. The second example of electrical circuit 42B is substantially similar to the first example. The primary difference is that electrical circuit 42B includes a superposition circuit 74 electrically connected to the positive output terminal of inverter 54, optionally by AC coupling capacitor C4. The negative output terminal of inverter 54 is electrically connected to ground.

[0085] The superimposing circuit 74 is configured to superimpose an AC signal on the DC current supplied by the DC / DC converter 58 to charge the capacitor 6. The superimposing circuit 74 includes an operational amplifier 76. The operational amplifier 76 includes the following: a non-inverting input terminal (labeled "+") electrically connected to a second semiconductor switch Q2 by a first resistor R1 and electrically connected to a first ground connection GND1 by a fifth capacitor C5 and a second resistor R2 in parallel. - an inverting input terminal (labeled "-") electrically connected to the output voltage terminal of inverter 54 by a third resistor R3 and an optional AC coupling capacitor C4 connected in series. a positive voltage terminal electrically connected in parallel with the non-inverting input terminal of the operational amplifier 76 to a second semiconductor switch Q2; - Negative voltage terminal electrically connected to the first ground connection GND1. an output voltage terminal electrically connected to the positive rail 60 of the switching circuit 50;

[0086] A junction 78 between the inverting input terminal and the third resistor R3 is electrically connected to the output voltage terminal of the operational amplifier 76 by a fourth resistor R4 and to a second ground connection GND2 by a fifth resistor R5.

[0087] The electrical circuit 42B also includes a bypass circuit 80 electrically connected in parallel between the input and output of the superposition circuit 74 (or, more specifically, electrically connected to a junction 82 between the second semiconductor switch Q2 and the positive voltage terminal of the operational amplifier 76, and to the positive rail 60, which is electrically connected to the output voltage terminal of the operational amplifier 76). The junction 82 may therefore represent the input of the superposition circuit 74. The bypass circuit 80 is configured so that the discharge current of the capacitor 6 is also supplied to the input of the superposition circuit 74 via the bypass circuit 80. The bypass circuit 80 includes a third semiconductor switch Q3 and a first diode D1, which prevents current from flowing from the input to the output of the superposition circuit 74 through the bypass circuit 80 (e.g., during charging of the capacitor). The MCU 56 includes a seventh input / output terminal (labeled “I / O”) electrically connected to the third semiconductor switch Q3 for switching it on and off.

[0088] A second diode D2 is included between the second semiconductor switch Q2 and the voltage output terminal of the DC / DC converter 58 to prevent the discharge current from reaching the voltage output terminal of the DC / DC converter.

[0089] An AC signal can be applied to the positive electrode of capacitor 6 during heating or non-heating mode by selectively enabling inverter 54. During heating mode, when capacitor 6 is being charged, the AC signal from inverter 54 is superimposed on the DC current from DC / DC converter 58 by superimposing circuit 74, so that the output of the superimposing circuit (i.e., the output voltage of operational amplifier 76) has both AC and DC components.

[0090] 7A-7D show the electrical circuit 42B as the capacitor 6 is being charged and discharged during the heating mode.

[0091] In Figure 7A, the second semiconductor switch Q2 is switched on, so that the capacitor 6 is charged (i.e., the DC / DC converter 58 is enabled and a DC current is supplied to the positive electrode of the capacitor 6 through the superposition circuit 74 (more specifically, through the operational amplifier 76)). The inverter 54 is not enabled, so that no AC signal is applied. The first and third semiconductor switches Q1, Q3 are switched off.

[0092] 7B, the capacitor 6 is charged and the inverter 54 is enabled, so that an AC signal is applied to the inverting input terminal of the operational amplifier 76. The AC signal from the inverter 54 is superimposed on the DC current from the DC / DC converter 68 by the superimposing circuit 74. Therefore, the amount of electrolyte can be estimated or determined by the MCU 56 even when the capacitor 6 is charged. The first and third semiconductor switches Q1, Q3 are switched off.

[0093] In Figure 7C, the capacitor 6 is discharged. The first semiconductor switch Q1 is switched on. The second semiconductor switch Q2 is switched off and / or the DC / DC converter 58 is not enabled. The inverter 54 is not enabled, so no AC signal is applied. The third semiconductor switch Q3 is switched off.

[0094] In Figure 7D, the capacitor 6 is being discharged. The first semiconductor switch Q1 is switched on. The second semiconductor switch Q2 is switched off, and / or the DC / DC converter 58 is not enabled. Because the inverter 54 is enabled, an AC signal is applied to the inverting input terminal of the operational amplifier 76. The third semiconductor switch Q3 is also switched on, so that current also flows through the bypass circuit 80, as shown. In particular, a portion of the discharging current from the capacitor 6 flows through the bypass circuit 80 to the input of the superposition circuit 74, defined by junction 82, and then to the non-inverting input terminal of the operational amplifier 76. Thus, the amount of electrolyte can be estimated or determined by the MCU 56 even when the capacitor 6 is being discharged.

[0095] In both the first and second examples of the electrical circuits 42A, 42B, an I2C communication protocol may be used for serial data communication between the MCU 56, the inverter 54, and the DC / DC converter 58. Other suitable communication protocols, such as SPI or UART, may also be used.

[0096] The amount of electrolyte remaining may be estimated or determined by MCU 56 from electrical parameters of capacitor 6, such as internal resistance or capacitance, which are known to vary with the amount of electrolyte. The electrical parameters of capacitor 6 may optionally be estimated or determined by superposition circuitry 74 using voltage and current measurements obtained when an AC signal is applied across positive electrode 16 and negative electrode 18 of capacitor 6, as described above.

[0097] The MCU 56 calculates the internal resistance or capacitance of the capacitor 6 primarily according to a Nyquist plot (or Cole-Cole plot). An example of a Nyquist plot 100 is shown in FIG. 8. The imaginary part of the complex impedance Z″ (or −Im(Z)) is the vertical axis, and the real part of the complex impedance Z′ (or Re(Z)) is the horizontal axis. The thick line 102 is a collection of the complex impedances corresponding to each frequency of the AC signal applied across the positive and negative electrodes 16, 18. The frequency of the AC signal can be swept one or more times over a wide frequency range (e.g., 1 MHz to 1 kHz) by the inverter 54. Alternatively, the frequency can be swept one or more times over several narrower frequency ranges (e.g., 500 Hz to 1 kHz, 1 Hz to 100 Hz, and 1 mHz to 1 Hz), or multiple different frequencies can be used to construct the Nyquist plot as described above. The MCU 56 calculates specific values ​​of the complex impedance corresponding to each frequency based on the input signal provided to the fifth input / output terminal electrically connected to the voltage sensing circuit 64 and the input signal provided to the sixth input / output terminal electrically connected to the current sensing circuit 66, particularly the current sensing amplifier 70. Because these input signals are AC signals, the MCU 56 may calculate the real part Z' and the imaginary part Z'' of the complex impedance by dividing the input signal from the voltage sensing circuit 64 by the input signal from the current sensing circuit 66. More specifically, the MCU 56 may plot dots on the diagram corresponding to the calculated real part Z' and imaginary part Z'' of the complex impedance for specific frequencies of the AC signal. As a result of the frequency sweep within the preferred frequency range, the individual dots form a thick line 102. In the example Nyquist plot shown in FIG. 8, the right portion corresponds to low frequencies and the left portion corresponds to high frequencies (i.e., the thick line 102 is plotted from right to left as the frequency of the AC signal is swept from low to high frequencies, and from left to right as the frequency of the AC signal is swept from high to low frequencies).

[0098] The example Nyquist plot shown in Figure 8 can be divided into two distinct regions: mass transfer process region 104 and charge transfer process region 106. The thick line 102 can be substantially linear in mass transfer process region 104 and substantially semicircular in charge transfer process region 106, as shown. The length of the thick line 102 within mass transfer process region 104 is proportional to the diffused resistance Z, shown in Figure 8 as part of the real equivalent capacitor circuit. w (where C if is the interfacial capacitance). The semicircular portion of the thick line 102 may have a first zero crossing 108 and a second zero crossing 110. The second zero crossing 110 is located on the boundary between the mass transfer process region 104 and the charge transfer process region 106. The distance between the origin and the first zero crossing 108 is the solution resistance R sol and the distance between the first zero crossing 108 and the second zero crossing 110 (i.e., the diameter of the semicircular portion of the thick line 102) corresponds to the charge transfer resistance R ct Corresponds to the solution resistance R sol and the charge transfer resistance R ct The sum of (i.e., the distance between the origin and the second zero crossing 110) corresponds to the internal resistance of the capacitor 6. The real part Z' of the complex impedance at the second zero crossing 110, the complex impedance Z(ω) at the second zero crossing 110, and the angular frequency ω at the second zero crossing 110 are used to calculate the imaginary part of the complex capacitance C''(ω), where

number

[0099] The imaginary part of the complex capacitance C''(ω) is directly proportional to the internal resistance of the capacitor 6. The amount of electrolyte can then be estimated or determined based on the imaginary part of the complex capacitance C''(ω), for example, using a look-up table.

[0100] The imaginary part Z″ of the complex impedance corresponds to the maximum point 112 of the semicircular portion of the thick line 102 along the vertical axis. Using the imaginary part Z″ of the complex impedance and the frequency f at the maximum point 112, the capacitance C of the capacitor is calculated from:

number

[0101] The amount of electrolyte can then be estimated or determined based on the capacitance C, for example, using a look-up table.

[0102] Note again that a wide frequency range including the first zero crossing 108 may not be necessary to estimate or determine the amount of electrolyte. In some cases, only a more limited frequency range around the second zero crossing 110 or peak 112 may be required.

[0103] During a vaping session, which may include a pre-heating phase and a subsequent heating or vaping phase, the MCU 56 may perform multiple electrolyte amount detection steps.

[0104] In an initial step performed at time T0 before the pre-heating phase begins, an initial value V0 of an electrical parameter of capacitor 6 is estimated or determined. This initial value V0 thus indicates the initial amount of electrolyte in capacitor 6 before the start of a vaping session. The initial value V0 is assumed to define a "baseline" against which subsequent values ​​can be compared. It is also assumed that the initial amount of electrolyte is a maximum amount. A visual display 52 shows the number "100%" to indicate to the user that capacitor 6 is filled with electrolyte.

[0105] In subsequent steps performed at times T1, T2, and T3, subsequent values ​​V1, V2, and V3 of the electrical parameter of capacitor 6 are estimated or determined. The subsequent steps may be performed in response to puff detection, which may be based on temperature changes or may use a standard flow sensor or microphone sensor, for example.

[0106] The initial value V0 and each of the subsequent values ​​V1, V2, and V3 are then used to estimate or determine the remaining amount of electrolyte. For example, the initial value V0 and the first subsequent value V1 are used to estimate or determine the amount of electrolyte at time T1, the initial value V0 and the second subsequent value V2 are used to estimate or determine the amount of electrolyte at time T2, etc. If the electrical parameter is directly proportional to the amount of electrolyte, i.e., whereby the electrical parameter decreases as the amount of electrolyte in capacitor 6 decreases, then at subsequent times T i The amount of electrolyte in may be estimated or determined by the following formula:

number

[0107] For example, if the subsequent value V1 is three-quarters of the initial value V0, the remaining amount of electrolyte may be calculated to be 75% of the initial amount at the start of the vaping session, and the number "75%" may be displayed to the user on the visual display 48. Similarly, if the subsequent values ​​V2 and V3 are one-half and one-third of the initial value V0, respectively, the remaining amount of electrolyte may be calculated to be 50% and 33% of the initial amount at the start of the vaping session, and the numbers "50%" and "33%" may be displayed to the user on the visual display 48.

[0108] If a subsequent value V3 is invalid (i.e., because it is too low, thus suggesting that too much electrolyte has evaporated since time T2, or because it is too high, suggesting that not enough electrolyte has evaporated since time T2), or if the electrolyte falls outside of an expected range, a different amount of electrolyte may be displayed to the user on the visual display 48. The expected range of value V3 may be based on a previously estimated or determined amount of electrolyte, such as the value V2 estimated or determined at time T2. For example, it may be expected that value V3 should be about 60% to about 70% of the previous value V2, and that if the value V3 estimated or determined at time T3 is outside this range (e.g., is only 20% of value V2), it may be invalid. If the value V3 is invalid, the amount of electrolyte notified to the user using the visual display 48 may instead be estimated using one or more previous amounts of electrolyte that were within the expected range. This may provide a more reliable notification to the user. For example, if the previous values ​​V1 and V2 are valid, they may be used to determine the rate of change of the electrolyte. This rate of change may then be applied to the value V2 estimated or determined in the previous step at time T2 to derive a substitute value for time T3. The determined rate of change may be linear or non-linear, for example. The substitute value is then communicated using visual display 48 in place of value V3 estimated or determined using the electrical parameters of capacitor 6.

[0109] While exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

[0110] Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0111] Unless the context clearly requires otherwise, throughout this specification and claims, the words "comprises," "including," and the like are to be construed in an inclusive, i.e., "including but not limited to," sense, as opposed to an exclusive or exhaustive sense.

Claims

1. A method for monitoring an aerosol generating article (1) equipped with a capacitor (6), wherein the capacitor (6) An electrolyte that generates an aerosol for the user to inhale when heated, A pair of electrodes (16, 18) and A porous separator (20b) between the pair of electrodes (16, 18), Includes, The method comprises estimating or determining the amount of electrolyte by applying an AC signal to one of the pair of electrodes (16).

2. The method according to claim 1, wherein the amount of the electrolyte is estimated or determined using one or more electrical parameters of the capacitor (6).

3. The method according to claim 2, wherein one or more electrical parameters of the capacitor are estimated or determined using at least one of voltage and current measurements obtained in response to the applied AC signal.

4. The method according to claim 2 or 3, wherein if the amount of electrolyte estimated or determined using the one or more electrical parameters is outside the expected range, the amount of electrolyte estimated or determined based on one or more previously estimated or determined amounts of electrolyte is notified to the user.

5. The method according to claim 1, further comprising generating an aerosol for a user to inhale by discharging and charging the capacitor (6) in order to heat the electrolyte.

6. The method according to claim 1, further comprising operating the capacitor (6) in a heating mode and a non-heating mode, wherein the alternating current AC signal is applied to the electrode (16) when the capacitor (6) is in the heating mode and the non-heating mode.

7. The method according to claim 1, further comprising operating the capacitor (6) in a heating mode and a non-heating mode, wherein the alternating current AC signal is applied to the electrode only when the capacitor (6) is in the non-heating mode.

8. Aerosol generation system, an aerosol generating article (1) comprising a capacitor (6), wherein the capacitor (6) An electrolyte that generates an aerosol for the user to inhale when heated, A pair of electrodes (16, 18) and A porous separator (20b) between the pair of electrodes (16, 18), Aerosol-generating article (1) including, An aerosol generating device (34) that receives the aerosol generating article (1), further comprising a controller (56) adapted to carry out the method described in claim 1, An aerosol generation system equipped with the following features.

9. Aerosol generation system, an aerosol generating article (1) comprising a capacitor (6), wherein the capacitor (6) An electrolyte that generates an aerosol for the user to inhale when heated, A pair of electrodes (16, 18) and A porous separator (20b) between the pair of electrodes (16, 18), Aerosol-generating article (1) including, The aerosol generating device (34) that receives the aerosol generating article (1) is, Power supply (44, 58) and A switching circuit (50) is electrically connected to the pair of electrodes (16, 18) and configured to control the discharge of the capacitor (6) and the charging of the capacitor (6) from the power supply (44, 58), An inverter (54) is electrically connected to one of the pair of electrodes (16) and configured to apply an AC signal to the electrode (16), The aerosol generating device (34) further includes, An aerosol generation system equipped with the following features.

10. The aerosol generating system according to claim 9, wherein the capacitor (6) is configured to operate in a heating mode and a non-heating mode, and the inverter (54) is configured to apply the AC signal to the electrode (16) when the capacitor (6) is in the heating mode and the non-heating mode.

11. The aerosol generating system according to claim 9 or 10, further comprising a superposition circuit (74) electrically connected to the inverter (54) and the switching circuit (50), and configured to superimpose the AC signal on the DC current supplied by the power supply (44, 58).

12. The aerosol generating system according to claim 11, further comprising an AC-coupled capacitor (C4) electrically connected in series between the inverter (54) and the superimposed circuit (74).

13. The aerosol generating system according to claim 11, further comprising a bypass circuit (80) electrically connected in parallel to the input (82) and output of the superimposed circuit (74), wherein the discharge current of the capacitor (6) is supplied to the input (82) of the superimposed circuit (74) via the bypass circuit (80).

14. The aerosol generating system according to claim 9, further comprising: a charging switch (Q2) configured to turn on and off the charging of the capacitor (6) from the power supply (44, 58); and a diode (D2) electrically connected between the power supply (44, 58) and the charging switch (Q2).

15. The aerosol generating system according to claim 9, wherein the switching circuit (50) and the inverter (54) are electrically connected in parallel to the capacitor (6), the capacitor (6) is configured to operate in a heating mode and a non-heating mode, and the inverter (54) is configured to apply the AC signal to the electrode (16) only when the capacitor (6) is in the non-heating mode.

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