Method of heating aerosol-generating article comprising electrolytic capacitor

Abstract

A method of heating an aerosol-generating article (1) is described. The article (1) includes a capacitor (6) having an electrolyte. The method includes at least one of discharging and charging the capacitor (6) to heat the electrolyte and thereby generate an aerosol for inhalation by a user.

Description

Technical Field

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

[0002] As part of an aerosol generating system of the present disclosure, an aerosol generating article may be received in an aerosol generating device comprising a controller suitable for carrying out the method.The present disclosure is particularly suitable for portable (handheld) aerosol generating devices. Background Art

[0003] In recent years, devices that generate an aerosol for inhalation by heating rather than burning an aerosol generating material have become increasingly popular with consumers. A commonly used risk reduction or risk modification device is a heated material aerosol generating device or a so-called heat-not-burn device. This type of device generates an aerosol or vapor by heating an aerosol generating material to a temperature typically in the range of 150°C to 300°C. This temperature range is quite low compared to ordinary cigarettes. Heating the aerosol generating material to a temperature within this range without burning or combusting the aerosol generating material produces a vapor, which typically cools and condenses to form an aerosol for inhalation by the user of the device.

[0004] Such a device may use one of a number of different methods to provide heat to the aerosol-generating material. All methods for heating the aerosol-generating material require some 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 an aerosol-generating article that can be used to supplement or partially replace the power source in the device. This can result in a smaller and lighter device, which is beneficial to the user, while maintaining accurate control of the heating of the aerosol-generating material and optimizing the characteristics of the generated aerosol. Summary of the invention

[0005] According to a first aspect of the present disclosure, there is provided a method of heating an aerosol-generating article comprising a capacitor, the capacitor comprising an electrolyte which, when heated, produces an aerosol for inhalation by a user. Thus, the electrolyte is aerosolizable, i.e., capable of being converted into an aerosol by heating, which is then inhaled by a user. Thus, heating the capacitor causes the electrolyte contained within the capacitor to be converted into an aerosol, which is then inhaled by the user. The method comprises at least one of discharging and charging the capacitor to heat the electrolyte and thereby produce an aerosol for inhalation by the user.

[0006] The capacitor may have any suitable configuration, but in a preferred embodiment, the capacitor is a supercapacitor, such as a double layer supercapacitor. The capacitor may further include a pair of electrodes and a porous separator between the electrodes. The first electrode may be a positive electrode and the second electrode may be a negative electrode, or vice versa. The electrodes and separator are immersed in an electrolyte.

[0007] Like conventional capacitors, in double-layer supercapacitors, charge is stored in the electric field between electrodes, and capacitance is a function of the surface area of ​​the electrodes, the distance between the electrodes, and the dielectric constant of the diaphragm material. Capacitors have a higher power density than conventional power sources (such as batteries). When the capacitor is charged by an external circuit connected to the pair of electrodes, cations in the electrolyte migrate toward the negative electrode and anions migrate to the positive electrode, while electrons travel from the negative electrode through the external circuit to the positive electrode. Therefore, two charge layers (double layers) with opposite polarities are formed at the interface with the electrodes. When charging is complete, the positive charge on the positive electrode and the anions in the electrolyte attract each other, while the negative charge on the negative electrode and the cations in the electrolyte attract each other, so as to stabilize the double layer on the electrode. A stable voltage is generated. When the capacitor is discharged, the opposite process occurs.

[0008] Each electrode may include at least one carbon-based electrode layer (eg, a porous carbon material or an activated carbon layer) having a high specific surface area per unit volume and compatibility with the proposed electrolyte.

[0009] Each electrode may further include a current collector, which may include a metal foil layer (e.g., an aluminum foil layer). The carbon-based electrode layer may be positioned 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 known for use in aerosol generating articles.

[0010] As will be understood by those of ordinary skill in the art, electrolyte achieves two functions. First, electrolyte allows cation migration and anion migration to occur when capacitor is charged or discharged, and secondly, electrolyte forms aerosol when heated, which is safely inhaled by the user and has good characteristics. Therefore, electrolyte should be selected accordingly. Electrolyte is preferably a food grade electrolyte and can, for example, include one or more of the following: 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 equivalent. Electrolyte can optionally include a gelling agent, such as polyvinyl alcohol, gellan gum or xanthan gum. In one example, electrolyte can include sodium chloride and glycerol and optionally polyvinyl alcohol as a gelling agent. It has been found that such electrolyte allows cation migration and anion migration and is also safe for user inhalation.

[0011] When all of the electrolyte has evaporated, the capacitor may not be further discharged or charged, and the article may need to be properly disposed of or refilled with electrolyte.

[0012] The separator must provide dielectric separation between the pair of oppositely charged electrodes. The separator also stores electrolyte in its pores and allows cations and anions to pass through during the charging process and the discharging process. The separator may include any suitable material. The separator may include plant-derived materials, in particular tobacco materials (e.g., porous tobacco sheets), or the separator may include any suitable cellulose or polypropylene-based materials. The separator material may release one or more volatile compounds when heated. These volatile compounds may include nicotine or flavor compounds (e.g., tobacco or other spices).

[0013] Aerosol generation article can further include any type of solid or semi-solid material downstream of the capacitor in the aerosol flow path. Example types of solid or semi-solid materials include debris, powder, particulate, pellet, fragment, line, granule, gel, strip, loose leaf, shredded filler, porous material, foam material or sheet. The material can include plant-derived material, particularly can include tobacco material. For example, the aerosol produced by heating the electrolyte of the capacitor will flow through the solid or semi-solid material, and the solid or semi-solid material can be positioned between the capacitor and the filter section or the mouthpiece, and the user inhales the aerosol through the filter section or the mouthpiece. The solid or semi-solid material can release one or more volatile compounds, which can, for example, add flavor and nicotine to the aerosol. Any heating provided by the capacitor also heats the solid or semi-solid material or heats the solid or semi-solid material, which can promote the release of volatile compounds.

[0014] The aerosol inhaled by the user consists essentially of vaporized or aerosolized electrolyte and optionally one or more volatile compounds, which may be released through the membrane material and / or downstream solid or semi-solid materials.

[0015] The capacitor can have any suitable configuration, such as a spirally wound (or "wound core") configuration (which can be generally cylindrical, or flattened so that it presents more of a cubic shape, for example, which may be better suited for a flat form article), a prismatic configuration, a folded or serpentine configuration, or a stacked configuration.

[0016] In one embodiment, the layered capacitor substrate may include a first electrode, a diaphragm adjacent to the first electrode, and a second electrode adjacent to the diaphragm, that is, the diaphragm is sandwiched between the first electrode and the second electrode, more particularly between 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 the electrodes facing or between different parts of the same electrode. In addition to the dielectric separation provided by the diaphragm, dielectric separation may also be provided, for example, by one or more dielectric material layers. The dielectric material may include any suitable material. The dielectric material may include a plant-derived material, and in particular may include a tobacco material (e.g., a porous tobacco sheet), or the dielectric material may include any suitable material based on cellulose or polypropylene. The dielectric material may release one or more volatile compounds when heated. These volatile compounds may include nicotine or flavor compounds (e.g., tobacco or other spices). The dielectric material and the diaphragm material may be the same or different.

[0017] In another embodiment, a layered capacitor substrate may include a first electrode, a first separator adjacent to the first electrode, a second electrode adjacent to the first separator (i.e., such that the first separator is sandwiched between the first electrode and the second electrode, more particularly between a pair of carbon-based electrode layers), and a second separator adjacent to the second electrode. The second electrode is sandwiched between the first separator and the second separator. The first electrode may be a positive electrode and the second electrode may be a negative electrode, or vice versa. Such a substrate is particularly suitable for a spirally wound (or "winding core") configuration, which may be generally cylindrical, or may be flattened so that it presents more of a cubic shape. The dielectric separation between the turns of the spirally wound capacitor is provided by a second separator, which may be sandwiched between the first electrode and the second electrode, more particularly between a pair of carbon-based electrode layers in the wound substrate.

[0018] In yet another embodiment, the layered capacitor substrate may include a plurality of first electrodes, a plurality of second electrodes, and a plurality of diaphragms. The first electrode may be a positive electrode, and the second electrode may be a negative electrode, or vice versa. The first electrode and the second electrode are alternately stacked so that the substrate includes a first electrode, a second electrode, a first electrode, a second electrode, etc. in the stacking direction. The diaphragm is sandwiched between each pair of electrodes, more particularly between a pair of carbon-based electrode layers, to provide dielectric separation. Such a substrate can be used for flat products. The first electrodes can be electrically connected together, and the second electrodes can be electrically connected together. The first electrode can be electrically connected to a first capacitor terminal, and the second electrode can be electrically connected to a second capacitor terminal.

[0019] The capacitor may be contained within a housing. More particularly, the housing may contain a capacitor substrate, including electrodes, a separator, etc., and an electrolyte. The electrolyte may be injected into the housing during the manufacturing process or when the capacitor needs to be refilled. The housing may electrically insulate the capacitor and may be formed of any suitable material or materials.

[0020] The housing may include, for example, a paper wrapper having a metal or polymer coating. The housing may include a pair of end caps formed of any suitable material. The housing may include appropriate perforations or openings, or may be combined with 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 the electrolyte from leaking when it is in a liquid or gel state. The aerosol-generating article may include a filter segment at the proximal end of the aerosol-generating article, the filter segment, for example, including cellulose acetate fibers. The filter segment may constitute a mouthpiece filter. In some designs, one or more vapor collection areas, vapor cooling areas, and other structures may also be included. The vapor cooling area may advantageously allow the vapor to cool and condense to form an aerosol having suitable properties for the user to inhale, for example, through the filter segment. Generally speaking, vapor is a substance that is in the gas phase at a temperature below its critical temperature, which means that the vapor can be condensed into a liquid by increasing its pressure without reducing the temperature, and an aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. However, it should be noted that the terms "aerosol" and "vapor" are used interchangeably in this specification.

[0021] The capacitor will preferably be pre-charged in the packaged article, i.e., when the capacitor is purchased by the user and before the capacitor is removably inserted into the aerosol generating device, the capacitor will already be charged. Pre-charging the capacitor reduces the amount of energy required to heat from the power supply of the device. This may result in a reduction in the size and weight of the device.

[0022] The aerosol generating device may be adapted to receive an aerosol generating article as described above during use. The device may include an external circuit (e.g., a switching circuit) that is electrically connected between a pair of electrodes or capacitor terminals when the article is received in the device. The switching circuit may be configured to control the discharge of the capacitor. The switching circuit may also optionally be configured to control the charging of the capacitor from a power source (e.g., a battery) of the device. Controlling the discharge and charging of the capacitor controls the heating of the electrolyte. 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, the short-circuit path allowing the charge stored in the capacitor to be discharged through the switching circuit. The switching device may include one or more switches. One or more switches may be semiconductor switching devices that may, for example, be connected as a bridge circuit or a converter circuit. One or more switches may be opened or closed or switched by a controller to provide a short-circuit path.

[0023] The switch circuit may include a first terminal and a second terminal, the first terminal being electrically connected to a first electrode or terminal of a capacitor when the aerosol generating article is received in the device, and the second terminal being electrically connected to a second electrode or terminal of the capacitor. Before the article is inserted into the device, in order to prevent accidental or intentional discharge of the pre-charged capacitor, it is preferred that at least one of the electrodes or terminals of the capacitor is not accessible to the user. For example, one or both of the capacitor electrodes or terminals may be hidden in the housing of the article and only accessible to form an electrical connection with the terminal of the switch circuit after the aerosol generating article has been inserted into the device or during the process of the aerosol generating article being inserted. The electrical connection may require the housing to be broken at one or more locations, and the device may include a device suitable for breaking, piercing or tearing the housing. The first terminal of the switch circuit may be directly electrically connected to the first electrode at one or more locations, or may be electrically connected to a first capacitor terminal, which in turn is electrically connected to the first electrode. Similarly, the second terminal of the switch circuit may be directly electrically connected to the second electrode at one or more locations, or may be electrically connected to a second capacitor terminal, which in turn is electrically connected to the second electrode. The capacitor terminals may be located anywhere on the article, for example near an end cap or side of the article. The orientation of the aerosol-generating article inserted into the device may be constrained to ensure proper alignment between the respective terminals, thereby providing a reliable electrical connection between the capacitor and the external switching circuit.

[0024] The terminals of the switching circuit can be formed as breaking devices, which are designed to break, pierce or tear the shell and form an electrical connection with the electrodes or terminals of the capacitor. The breaking device can be fixed to the device or stationary relative to the device, and can be designed to break, pierce or tear the shell when the product is inserted into the device (for example, inserted into the aerosol generation space or heating chamber). The breaking device can also be movable. For example, in one arrangement, the breaking device can be installed on a panel or door-shaped member of the device, which is opened or removed to allow the product to be inserted, and wherein the breaking device is designed to break, pierce or tear the shell when the panel or door-shaped member is closed by the user. For example, the panel or door-shaped member can be hinged. In another arrangement, the breaking device can be moved by a suitable actuator (for example, an electric motor or a piston), which can force the breaking device to pass through the shell and form an electrical connection. The breaking device can move through the opening or slot in the part of the device that limits the aerosol generation space or the heating chamber. The breaking device can have any suitable shape and can be formed, for example, as a needle or crown with one or more pointed ends, a blade with a cutting edge, or a punch with a non-pointed end. The breaking device can be designed to work with any of the above capacitor configurations. If one of the electrodes or terminals of the capacitor is accessible, only one breaking device is required.

[0025] Discharging the pre-charged capacitor by an external circuit (such as the switching circuit of the device) will generate heat in the electrodes, which in turn heats the electrolyte in which the electrodes are immersed. Sufficient heating of the electrolyte will produce an aerosol for the user to inhale during the inhalation process. In order to improve heating, the internal resistance of the capacitor can be increased by increasing the thickness of the diaphragm between the electrodes with opposite charges. If the overall size remains the same, this can make the capacitor have fewer turns or folds. Charging the capacitor using an external circuit will also generate heat in the electrodes, which in turn heats the electrolyte to produce an aerosol to be inhaled.

[0026] The discharge and optional charging of the capacitor and thus the heating of the electrolyte can be controlled using a switching circuit, which can be a part of the aerosol generating device. The device can also include an external heater, which is used to heat the capacitor to produce an aerosol for the user to inhale. In other words, the heating of the electrolyte is not limited to the heat generated by the capacitor when discharging or charging, but the capacitor can be heated by an external heater in a manner similar to conventional aerosol generating materials or substrates. Such heating will still heat the electrolyte to produce an aerosol to be inhaled. Using an external heater can provide more controlled heating during certain stages of the suction process, thereby optimizing the user's experience. Any suitable heater can be used, such as a low-power film heater, a printed heater, etc. For example, during the initial preheating stage, the heat generated by the capacitor discharge can be used, and during the subsequent heating or suction stage, an external heater can be used to heat the electrolyte to produce an aerosol. Therefore, the power for preheating can be provided at least in part by a capacitor rather than by the power supply of the device. This can make the power supply smaller, so that the device is smaller and lighter. Alternatively, during the subsequent heating or suction phase, the electrolyte can be heated by the charging and discharging of the cycle of the capacitor. During the heating or suction phase, there may be a time when heating is not required, so the capacitor does not need to be discharged or charged. When heating is required, the capacitor can be continuously discharged or charged, or the capacitor can be used, for example, to discharge or charge intermittently using a suitable duty cycle. In this alternative embodiment, an external heater can be used to heat the electrolyte during the initial preheating phase. The preheating phase can generally be intended to preheat the electrolyte to a target temperature, and the heating or suction phase can generally be intended to heat the electrolyte for a longer time period, generating an aerosol during this time period. If an external heater is not required, then because heating can be provided entirely by the capacitor, the cost of the device can be reduced and the overall design can be simplified.

[0027] If heating can be provided entirely by the capacitor, the aerosol-generating article can be formed as a single-use or disposable device that does not need to be inserted into another device. In other words, the aerosol-generating article may include external circuitry (e.g., a switching circuit) for controlling the discharge of the capacitor and any other components required for the normal operation of the single-use or disposable device.

[0028] In some cases, discharging the capacitor can provide sufficient heating without charging the capacitor. For example, the capacitor can be continuously or intermittently discharged through a switching circuit to provide sufficient heating of the electrolyte during at least the preheating phase. Thereafter, heating can be provided by an external heater. The method can also include cycling the capacitor between discharging and charging. Repeatedly cycling the capacitor between discharging and charging can provide continuous heating of the capacitor during certain stages of the use process without the need for an external heater.

[0029] The capacitor can be discharged and / or charged between predefined upper and lower limits. For example, if the state of charge (SOC) is expressed, the upper limit can be about 50%-80% and the lower limit can be about 20%-40%. The SOC is defined here as the available capacity of the capacitor (in Ah) and is expressed as a percentage of its rated capacity. It should be understood that other predefined upper and lower limits can be selected, and they can be expressed, for example, in different terms (such as voltage). Since the output voltage of the capacitor corresponds to the SOC of the capacitor, if the output voltage of the capacitor is used instead of the SOC, the calculation load can be reduced. Using appropriately selected upper and lower limits can avoid problems (such as nonlinear effects or unacceptably large discharge currents or charging currents) that may be encountered when the capacitor is substantially fully charged (e.g., above about 80%) or substantially fully discharged (e.g., below about 20%) when heating the electrolyte.

[0030] At the beginning of the priming process, the capacitor can be discharged or can cycle between discharge and charge until a threshold temperature is reached, after which the capacitor is heated by an external heater. Using an external heater can, for example, provide more consistent heating during the heating or priming phase. For example, the threshold temperature can be about 180°C to 230°C. The heating provided by the external heating can heat the capacitor to a target temperature (e.g., about 280°C).

[0031] The discharge and / or charging of the capacitor may be controlled based on the estimated or determined temperature.For example, the temperature may be the estimated or determined temperature of the capacitor.

[0032] A temperature sensor may be used to measure the temperature for controlling the discharge and / or charging of the capacitor. For example, the aerosol-generating device may include a temperature sensor located near the capacitor when the aerosol-generating article is received in the device, or may be configured to measure the temperature of a terminal of an external circuit that is in thermal and electrical contact with a corresponding electrode of the capacitor. The terminal may be a positive terminal of the external circuit.

[0033] The temperature can also be estimated based on the electrical parameters of the capacitor. In other words, the capacitor can be used as a temperature sensor. It is known that the electrical parameters vary with the temperature of the capacitor. During the course of the use process, the reduction in the amount of electrolyte will cause the electrical parameters to change, and it may be necessary to compensate for this. For example, at least one of the current measurement, voltage measurement and time measurement taken when the capacitor is discharged or charged can be used to estimate or determine one or more values ​​of the electrical parameters of the capacitor. For example, the electrical parameter can be the internal resistance or capacitance of the capacitor. For example, the internal resistance R of the capacitor is DC It can be estimated or determined according to the following equation:

[0034]

[0035] Where ΔV is the initial voltage step when the capacitor is discharged or charged, and I is the discharge current or charge current, which is usually constant.

[0036] The capacitance C of a capacitor can be estimated or determined according to the following equation:

[0037]

[0038] Where t1 and t2 are the discharge time or charge time when the voltages are V1 and V2, respectively. Only a small voltage difference is needed to estimate or determine the capacitance of a capacitor. The capacitance of a capacitor can also be estimated or determined by integrating the discharge current or charge current ("Coulomb counting").

[0039] The electrical parameter can be used to estimate the temperature of the capacitor using a suitable linear or nonlinear function or lookup table, which, for example, relates the value of the electrical parameter to the temperature. Using one or more values ​​of the electrical parameter of the capacitor to estimate the temperature of the capacitor is described in more detail below in the context of the temperature estimation step.

[0040] The discharge and / or charging of the capacitor may be controlled based on a comparison between the estimated or determined temperature and a target temperature or temperature profile.

[0041] The discharge and / or charging of the capacitor and thus the heating of the electrolyte can be controlled by changing the power at which the capacitor is discharged and / or charged through a switching circuit electrically connected between a pair of electrodes or terminals of the capacitor. For example, the discharge and / or charging power can be changed by controlling the switching device of the switching circuit so that the capacitor is intermittently discharged or charged using an appropriate duty cycle, for example, wherein the switching device is periodically enabled and disabled at a duty cycle that can be changed to control the rate at which the capacitor is discharged or charged. More specifically, the time (or "pulse width") at which the switching device is enabled can be changed based on the estimated or determined temperature of the capacitor. During the time period when the switching device is enabled, one or more switches (e.g., semiconductor switches) can be turned on and off as appropriate. During the time period when the switching device is disabled, one or more switches can be turned off. Each time the temperature of the capacitor is estimated or determined, the discharge and / or charging power can be adjusted. The discharge power and the charging power can be controlled separately.

[0042] The switching device of the switching circuit can be controlled by a closed-loop controller having one or more controller constants (or gains). For example, the closed-loop controller can be a PID controller having a proportional constant, an integral constant, and a differential constant. However, other closed-loop controllers can also be used. One or more controller constants can be changed based on at least one of the following:

[0043] - estimated or determined values ​​of electrical parameters of the capacitor, and

[0044] -The estimated or determined temperature of the capacitor.

[0045] If the electrical parameters of the capacitor are reduced and changed during the suction process due to the heating of the electrolyte and / or the amount of electrolyte as the electrolyte is inhaled by the user as an aerosol, then changing one or more controller constants allows the discharge and / or charging of the capacitor to be regulated. The electrical parameter can be, for example, an electrical parameter (such as the internal resistance or capacitance of the capacitor) that is expected to change with the amount of electrolyte and / or the internal temperature of the capacitor. Being able to dynamically change the controller constant in the process of the suction process can provide more consistent heating of the electrolyte, thereby enhancing the user's experience. The value of the electrical parameter can be estimated or determined using at least one of the current measurement, voltage measurement and time measurement obtained when the capacitor is discharged or charged. For example, one or more controller constants can be changed using a suitable automatic tuning process, which can use a neural network or any other type of adaptive control or learning process or a process based on a model. The automatic tuning process can use a lookup table that, for example, associates an electrical parameter or temperature with a specific controller constant.

[0046] The method may further include an identification step in which at least one of discharging and charging the capacitor over a period of time is performed, and the value of an electrical parameter of the capacitor is estimated or determined. The capacitor may be discharged and / or charged multiple times. The time period for each discharge or charge is preferably very short (e.g., about 10ms to 100ms), and the identification step is not intended to cause any significant discharge or charge of the capacitor. At least one of the current measurement, voltage measurement, and time measurement taken during each discharge or charge can be used to determine the average value of the electrical parameter of the capacitor. For example, the electrical parameter may be the internal resistance, capacitance, discharge rate or charge rate, SOC, or health state (SOH) of the capacitor. The value of the electrical parameter (or current measurement, voltage measurement, and time measurement) can be used to determine at least one of the following:

[0047] - the operating parameters or conditions of the capacitor, and

[0048] - Authenticity of aerosol generating articles.

[0049] Determining the operating parameter or state of the capacitor may include determining whether the article is damaged or faulty. For example, if the capacitor does not react as expected when discharged or charged during the identification step, it may indicate that the electrical connection to the switching circuit is faulty, the capacitor is damaged causing an internal short circuit, or there may not be enough electrolyte. For example, the value of the electrical parameter of the capacitor estimated or determined during the identification step can be used to adjust the operating characteristics of the device. For example, if the value of the electrical parameter is within a predefined range or is above or below a predefined threshold, authenticity can be established. If the article is not authentic, further operation of the device can be stopped.

[0050] The identification step may be performed by the controller prior to a pre-heating phase of the aerosol-generating article. For example, the identification step may be performed when the article is inserted into the device.

[0051] The method may further include a temperature estimation step, in which at least one of discharging and charging the capacitor over a period of time is performed, and the value of an electrical parameter of the capacitor is estimated or determined. The capacitor may be discharged and / or charged multiple times. At least one of the current measurement, voltage measurement, and time measurement obtained during each discharge or charge can be used to determine the average value of the electrical parameter of the capacitor. The value of the electrical parameter (or current measurement, voltage measurement, and time measurement) can be used to estimate the temperature of the capacitor, for example, using a suitable linear or nonlinear function or lookup table to estimate, which linear or nonlinear function or lookup table associates the electrical parameter with the temperature. The electrical parameter may be an internal resistance or capacitance of the capacitor, for example, the internal resistance or capacitance is proportional to the temperature of the capacitor.

[0052] For example, the temperature estimating step may be performed by the controller at regular or irregular intervals during at least one of a pre-heating phase and a subsequent heating phase.

[0053] According to a second aspect of the present disclosure, there is provided an aerosol generating system, the aerosol generating system comprising:

[0054] An aerosol-generating article comprising a capacitor (e.g., an electric double layer supercapacitor) comprising an electrolyte that, when heated, generates an aerosol for inhalation by a user; and

[0055] An aerosol-generating device in which the aerosol-generating article is received, the aerosol-generating device further comprising a controller adapted to implement the above method.

[0056] The apparatus may further include a switching circuit electrically connected between a pair of electrodes of the capacitor.

[0057] The apparatus may further comprise a heater adapted to heat the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a diagrammatic view of a first example of an aerosol-generating article;

[0059] Figure 2 is a diagrammatic view of a first example of a capacitor having a spirally wound configuration;

[0060] Figure 3 It is along Figure 2 A cross-sectional view of line AA in FIG.

[0061] Figure 4 is a diagrammatic view of an aerosol generating device;

[0062] Figure 5 is a schematic representation of a switching circuit;

[0063] Figure 6 It is a representation of the temperature curve during the preheating and heating phases of the suction process;

[0064] Figure 7 is a representation of the different temperature profiles during the preheating phase and the heating phase of the imbibition process; and

[0065] Figure 8 is a schematic representation of a controller. DETAILED DESCRIPTION

[0066] Embodiments of the present disclosure will now be described, by way of example only, and with reference to the accompanying drawings.

[0067] First reference Figure 1 , diagrammatically shows an example of an aerosol-generating article 1 . The article 1 has a proximal end 2 and a distal end 4 .

[0068] The article 1 comprises a capacitor 6 comprising an electrolyte. The capacitor 6 is surrounded by a paper wrap 8 having a metal or polymer coating. An end cap 10a, 10b is provided at each end of the capacitor 6. The paper wrap 8 and the end caps 10a, 10b define a housing for the capacitor 6 which contains the electrolyte and provides electrical insulation.

[0069] The article 1 is generally cylindrical.

[0070] At the proximal end 2, the article 1 includes a mouthpiece 12 having an outlet 14 through which a user can inhale an aerosol generated by heating the electrolyte. Although not shown, the proximal end cap 10a may include appropriate perforations or openings, or incorporate a suitable aerosol-permeable membrane material, so that the generated aerosol can pass through the end cap to the outlet 14.

[0071] refer to Figure 2 The capacitor 6 is a double-layer supercapacitor and has a generally cylindrical, spirally wound (or "jellyroll") configuration. 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 20a, 20b. Figure 3 As more clearly shown in FIG. 1 , the positive electrode 16 includes a positive current collector 22. Each side of the positive current collector 22 is provided with a porous carbon-based electrode layer 24, such as a porous carbon material or an activated carbon layer, for example. The negative electrode 18 includes a negative current collector 26. Each side of the negative current collector 24 is provided with a porous carbon-based electrode layer 28, such as a porous carbon material or an activated carbon layer, for example. For example, the positive current collector 22 and the negative current collector 26 are aluminum foil layers.

[0072] Barrier film 20a, 20b is formed by tobacco material (such as porous tobacco sheet), and this tobacco material releases volatile compounds when heated.In the alternative arrangement not shown, barrier film can be formed by suitable material based on cellulose or polypropylene, and electrolyte can flow through tobacco material (such as tobacco scraps), and this tobacco material is in the aerosol flow path at the capacitor downstream.Tobacco material can be positioned between capacitor and mouthpiece.Tobacco material adds local flavor and nicotine to aerosol.The heating provided by capacitor also heats tobacco material or makes tobacco material heat up, and this promotes the release of volatile compounds.Can use the flavor source without nicotine, and do not use tobacco material.

[0073] The electrodes 16, 18 and the diaphragms 20a, 20b are immersed in an electrolyte that allows cations and anions to migrate when the capacitor 6 is charged or discharged, and that, when heated, produces an aerosol for inhalation by the user. The electrolyte may contain sodium chloride and glycerol and, optionally, polyvinyl alcohol as a gelling agent. However, other food grade electrolytes may also be used. The capacitor 6 is pre-charged during the manufacturing process and is packaged and sold to the user in a pre-charged state.

[0074] The article 1 includes a capacitor positive terminal 30, which is electrically connected to the positive electrode 16 (i.e., to the positive current collector 22) at one or more locations; and a capacitor negative terminal 32, which is electrically connected to the negative electrode 18 (i.e., to the negative current collector 26) at one or more locations. The capacitor terminals 30, 32 can be located inside the housing of the article 1 so that they cannot be touched by the user. This helps prevent accidental or intentional discharge of the capacitor 6 before the article is removably inserted into the aerosol generating device to prepare for the inhalation process.

[0075] Figure 4 There is shown an aerosol-generating device 34 suitable for receiving an aerosol-generating article 1. The device 34 comprises a cavity 36 into which the article 1 can be inserted.

[0076] The device 34 includes a pair of break-out devices 38, 40 adapted to break the distal end cap 10b of the article 1 when the article 1 is inserted into the cavity 36. When the article 1 is inserted into the cavity 36, the angular orientation of the article relative to the device 34 can be constrained so that the break-out device 38 forms an electrical connection with the positive electrode 30 and the break-out device 40 forms an electrical connection with the negative electrode 32. Other ways of ensuring a reliable electrical connection can be used. For example, the positive and negative terminals of the article can have an annular configuration and be positioned coaxially with each other so that a properly positioned break-out device will form an electrical contact with the terminals regardless of the angular orientation of the article relative to the device.

[0077] The device 34 includes a switching circuit 42 and a power source 44 (such as a battery).

[0078] An example of the switch circuit 42 is as follows Figure 5 As shown. The switch circuit 42 includes breakout devices 38, 40, which serve as positive and negative terminals and are electrically connected to the positive terminal 30 and negative terminal 32 of the article 1 when the article 1 is properly received in the cavity 36. The switch circuit 42 includes a switch device 46, which can be operated by a controller 48 to control the discharge of the capacitor 6 through the switch circuit 42, thereby controlling the heating of the electrolyte. The controller 48 may include at least one microcontroller unit (MCU) or microprocessor unit (MPU).

[0079] After the article 1 has been inserted into the device 34, the capacitor 6 can be discharged by controlling the switching device 46 so as to provide a continuous or switched short-circuit path between the positive terminal 30 and the negative terminal 32 of the article 1, and therefore between the positive electrode 16 and the negative electrode 18 of the capacitor 6. The short-circuit path between the positive terminal 30 and the negative terminal 32 is formed via the switching device 46. In addition, the switching device 46 may include a resistor to prevent excessive discharge current or an electrical load that enables constant current discharge. If the discharge current is maintained at a predetermined value, the current sensor mentioned below can be omitted. Discharging the capacitor 6 through the switching circuit 42 dissipates the heat in the electrodes 16, 18. This heats the electrolyte and generates an aerosol that the user can inhale through the outlet 14 in the mouthpiece 12. Pre-charging the capacitor 6 reduces the amount of energy required for heating from the power supply 44 of the device. This can reduce the size and weight of the device 34. In particular, the size and weight of the power supply 44 can be reduced. This is important because the power supply is usually the largest and heaviest component of the device. In some cases, the energy for heating can be completely provided by capacitor 6, and power supply 44 can be omitted or only used to provide power for other components (such as controller) of the device. However, in other cases, the energy provided by capacitor 6 will be used to supplement or partially replace the energy provided by power supply 44.

[0080] The capacitor 6 can also be charged from the power source 44 by controlling the switch means 46 (or a separate switch means of the switch circuit, not shown). Charging the capacitor 6 also dissipates heat in the electrodes 16, 18, which heats the electrolyte and generates an aerosol that the user can inhale through the outlet 14 in the mouthpiece 12. Thus, heat can be repeatedly generated by charging the capacitor 6 from the power source 44 and then discharging the capacitor through the switch circuit 42.

[0081] For example, the switch device 46 that can be used to achieve the above-mentioned discharge and charging of the capacitor 6 can include one or more switches. The discharge switch for controlling the discharge current of the capacitor 6 can be connected in series between the break devices 38, 40, which define the positive terminal and the negative terminal of the switch circuit 42. The charging switch for controlling the charging current of the capacitor 6 can be connected in series between the break device 38 defining the positive terminal of the switch circuit 42 and the positive terminal of the power supply 44 and / or between the break device 40 defining the negative terminal of the switch circuit 42 and the negative terminal of the power supply. These switches can be semiconductor switch devices, such as transistors.

[0082] Although not shown, the device 34 may include a current sensor for measuring the discharge current or the charging current of the capacitor 6 and a voltage sensor for measuring the voltage output by the capacitor. For example, the measurement values ​​provided by the current sensor and the voltage sensor are used to determine the electrical parameters of the capacitor, such as the internal resistance or capacitance.

[0083] The device 34 may optionally include one or more heaters 50. The heater 50 may be used to heat the electrolyte in the capacitor 6 to generate an aerosol that the user may inhale through the outlet 14 in the mouthpiece 12. Such heating may be used to better control the heating of the electrolyte, for example during the heating or inhalation phase.

[0084] The device 34 includes a temperature sensor 52 for estimating or determining the temperature of the capacitor 6. The temperature sensor 52 may be located in the cavity 36 of the device 34, or may be adapted to measure the temperature of a positive terminal of the switching circuit 42, which is in thermal and electrical contact with the positive electrode 16 (more particularly, the positive current collector 22) of the capacitor 6. The temperature measurement provided by the temperature sensor 52 may be used to estimate the internal temperature of the capacitor 6 (e.g., by applying a suitable temperature offset).

[0085] Figure 6 It represents the suction process including the preheating phase PHP and the heating or suction phase VP.

[0086] Before the preheating phase begins, for example when the article 1 is inserted into the device 34, an identification step (indicated by "(0)") is performed to determine the operating parameters and state of the capacitor and to check the authenticity of the aerosol-generating article. During the identification step, the pre-charged capacitor 6 is discharged a number of times (e.g., five times). Each discharge lasts only for a very short period of time (e.g., about 10 ms to 100 ms). At least one of the current measurement, voltage measurement, and time measurement taken during each discharge is used to determine the average value of an electrical parameter of the capacitor 6 (such as the internal resistance, capacitance, discharge rate, SOC or SOH of the capacitor). The average value of the electrical parameter can be used to detect whether the article 1 is damaged or malfunctioning. The average value of the electrical parameter of the capacitor 6 can also be used to adjust the operating characteristics of the device. For example, if the average value of the electrical parameter is within a predefined range or is above or below a predefined threshold, the authenticity of the aerosol-generating article 1 can be established. If the article 1 is not authentic, further operation of the device 34 can be stopped.

[0087] During the priming process, the heating of the electrolyte is controlled by controlling the discharge and charging of the capacitor 6 based on the estimated or determined temperature of the capacitor. The discharge and charging of the capacitor 6 are controlled based on a comparison between the estimated or determined temperature and a target temperature or a temperature curve. The discharge power and the charging power of the capacitor 6 are changed by the switching circuit 42. In particular, the discharge power and the charging power are changed by controlling the switching device 44 of the switching circuit 42.

[0088] The discharge power and the charge power may be adjusted after each temperature estimation or determination.

[0089] During the preheating phase PHP, the capacitor 6 repeatedly cycles between discharge and charge to continuously heat the capacitor (indicated by "(1)"). The capacitor 6 is discharged and charged at specific discharge power and charge power as shown, which can quickly heat the capacitor to the target temperature.

[0090] During the absorption phase VP, the discharge and charging of the capacitor are controlled to change the temperature of the capacitor according to the temperature curve to provide the desired heating of the electrolyte. For example, if the capacitor 6 is to be maintained at a specific temperature to provide substantially constant heating of the electrolyte, the capacitor can be discharged and charged at a specific discharge power and charging power (indicated by "(2)"), wherein the discharge power and charging power can be considered to be lower than the discharge power and charging power during the pre-heating phase PHP where faster heating is required. If the capacitor temperature needs to be reduced, the switching device 44 can be disabled so that the capacitor is neither discharged nor charged, and no heating is provided (indicated by "(3)"). If the capacitor temperature needs to be increased to provide additional heating of the electrolyte, the capacitor can be discharged and charged at a specific discharge power and charging power (indicated by "(1)"), wherein the discharge power and charging power can be considered to be higher than the discharge power and charging power used to maintain the capacitor temperature (indicated by "(2)"). Therefore, Figure 6 It is shown how the heating of the electrolyte can be varied by controlling the discharge power and the charge power of the capacitor 6 in order to control the amount of heat dissipated in the electrodes.

[0091] The capacitor 6 is discharged and charged between predefined upper and lower limits. Figure 6 In the figure, the upper and lower limits are expressed by SOC, the upper limit is about 50%-80%, and the lower limit is about 20%-40%.

[0092] Figure 7 It represents an alternative imbibition process comprising a preheating phase PHP and a heating or imbibition phase VP.

[0093] Before the pre-heating phase PHP begins, for example when the article 1 is inserted into the device 34, an identification step (indicated by "(0)") is performed to determine the operating parameters and state of the capacitor and to check the authenticity of the aerosol-generating article.

[0094] At the beginning of the preheating phase PHP, the capacitor 6 repeatedly cycles between discharging and charging until a threshold temperature is reached (indicated by "(1)"). Once the threshold temperature has been reached, the capacitor 6 is not discharged or charged, and the capacitor is heated by one or more heaters 50 (indicated by "(2)"). For example, the threshold temperature may be approximately 180° C. to 230° C. The heating provided by the external heater 50 may heat the capacitor 6 to a target temperature of approximately 280° C.

[0095] The temperature estimation step is performed while the capacitor 6 is heated by one or more external heaters 50. In each temperature estimation step, the capacitor 6 is charged and discharged multiple times (e.g., three times). An average value of an electrical parameter of the capacitor 6 is determined using at least one of the current measurement, voltage measurement, and time measurement taken each time the capacitor is discharged and / or charged. The average value of the electrical parameter is then used to estimate the temperature of the capacitor 6. The electrical parameter may be an internal resistance or capacitance of the capacitor 6, for example, which is proportional to the temperature of the capacitor.

[0096] refer to Figure 8 , the switch device 44 of the switch circuit 42 is controlled by a controller 48 including a closed-loop controller 54. The temperature measurement value T from the temperature sensor 52 is provided to a temperature estimation block 56. The temperature estimation block 56 also receives the value EP of an electrical parameter (such as internal resistance or capacitance) of the capacitor 6, which can be estimated or determined using the current measurement value and the voltage measurement value. The temperature estimation block 56 outputs an estimated temperature ST of the capacitor based on the temperature measurement value T and / or the value EP of the electrical parameter.

[0097] An error E between the estimated capacitor temperature ST and the temperature profile TP is calculated and provided to a closed-loop controller 54 , which controls the switching device 44 .

[0098] The closed-loop controller 54 has a proportional constant K P , integration constant K I and the differential constant K D The controller constants are changed by the auto-tuning block 58 based on at least one of the following:

[0099] - the value EP of the electrical parameter of the capacitor 6, and

[0100] - Temperature measurement value T.

[0101] If the electrical parameters of the capacitor 6 change during the puffing process due to heating of the electrolyte and / or reduction in the amount of electrolyte as the electrolyte is inhaled by the user as an aerosol, then changing the controller constants allows for regulation of the discharge and / or charging of the capacitor 6. This allows the controller to provide robust and accurate heating control throughout the puffing process.

[0102] For example, the auto-tuning block 58 may use a neural network or any other kind of adaptive control or learning process, or a model-based process. The auto-tuning block 58 may also use a lookup table that relates, for example, an electrical parameter or temperature to a specific controller constant.

[0103] Although exemplary embodiments have been described in the preceding paragraphs, it should be appreciated that various modifications can be made to these embodiments without departing from the scope of the appended claims. Therefore, the breadth and scope of the claims should not be limited to the exemplary embodiments described above.

[0104] Unless otherwise indicated herein or clearly contradicted by context, this disclosure encompasses any combination of the above-described features in all possible variations thereof.

[0105] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise," "comprising," and the like are to be interpreted in an inclusive rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

Claims

1. A method of heating an aerosol generating article (1) comprising a capacitor (6), the capacitor (6) comprising an electrolyte, the method comprising at least one of discharging and charging the capacitor (6) to heat the electrolyte and thereby generate an aerosol for inhalation by a user.

2. The method according to claim 1, wherein: The capacitor (6) cycles between discharging and charging.

3. The method according to claim 1 or claim 2, wherein: The discharge and / or charging of the capacitor (6) is controlled based on the estimated or determined temperature.

4. The method according to claim 3, wherein: The temperature is a measured temperature or is estimated or determined based on at least an electrical parameter of the capacitor (6).

5. The method according to claim 3 or 4, wherein: The discharge and / or charging of the capacitor (6) is controlled based on a comparison between the estimated or determined temperature (ET) and a target temperature or temperature profile (TP).

6. A method according to any preceding claim, wherein: The capacitor (6) further comprises a pair of electrodes (16, 18), and wherein the discharge and / or charge of the capacitor (6) is controlled by changing the power of the discharge and / or charge of the capacitor (6) through a switch circuit (42) electrically connected between the pair of electrodes (16, 18).

7. The method according to claim 6, wherein: The switching device (44) of the switching circuit (42) is controlled by a closed loop controller (54) having one or more controller constants.

8. The method according to claim 7, wherein: The one or more controller constants are varied based on at least one of: - estimated or determined values ​​of electrical parameters of the capacitor (6), and - the estimated or determined temperature of the capacitor (6).

9. A method according to any preceding claim, wherein: The capacitor (6) is discharged or cycles between discharge and charge until a threshold temperature is reached, after which the capacitor (6) is heated by an external heater (50).

10. A method according to any preceding claim, further comprising an identification step in which the capacitor (6) is at least one of discharged and charged over a period of time and a value of an electrical parameter of the capacitor (6) is estimated or determined, wherein The value of the electrical parameter is used to determine at least one of the following: - an operating parameter or state of the capacitor (6), and - the authenticity of the aerosol-generating article (1).

11. The method according to claim 10, wherein: The identification step is performed prior to a pre-heating phase (PHP) of the aerosol-generating article (1).

12. A method according to any preceding claim, further comprising a temperature estimation step, in which the capacitor (6) is at least one of discharged and charged over a period of time and the value of an electrical parameter of the capacitor (6) is estimated or determined, wherein The value of the electrical parameter is used to estimate the temperature of the capacitor (6).

13. The method according to claim 12, wherein: This temperature estimation step is performed at regular or irregular intervals during at least one of the preheating phase (PHP) and the subsequent heating or purge phase (VP).

14. An aerosol generating system comprising: An aerosol generating article (1) comprising a capacitor (6) comprising an electrolyte which, when heated, generates an aerosol for inhalation by a user; as well as An aerosol generating device (34) in which the aerosol generating article (1) is received, the aerosol generating device (34) further comprising a controller (48) adapted to implement a method according to any one of the preceding claims.

15. An aerosol generating system according to claim 14, wherein: The capacitor (6) further comprises a pair of electrodes (16, 18), and the device (34) further comprises a switching circuit (42) electrically connected between the pair of electrodes (16, 18), and optionally a heater (50).

Images