Aerosol generating device

Abstract

An aerosol generating device (100) is disclosed, comprising: a heating chamber (116) for receiving an aerosol generating substance and a heater (118) arranged to heat an aerosol generating substance received in the heating chamber; a battery (108) configured to operate at or below a first maximum temperature; and one or more energy storage devices (106, 124) configured to operate at or below a second maximum temperature that is higher than the first maximum temperature; wherein the battery is configured to provide electrical power to at least one of the heater and the one or more energy storage devices, and the one or more energy storage devices are positioned between the battery and the heating chamber.

Description

[0001] AEROSOL GENERATING DEVICE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to aerosol generating devices. In particular, the invention relates to aerosol generating devices configured to heat but not bum tobacco.

[0004] BACKGROUND

[0005] There is a demand for more compact aerosol generating devices that are easier for the user to hold and store. Safe thermal management of aerosol generating devices is a competing concern, in particular for devices configured to heat an aerosol generating material without burning it (“heat-not-burn” devices), which often operate at relatively high temperatures. For instance, reducing air gaps within the device provides a more compact device but makes it easier for heat to flow from the heater to other components of the device. There is also a need for aerosol generating devices that require recharging less often. Larger batteries are one way this can be achieved; however, using a larger battery also makes the device less compact.

[0006] There is also an increasing demand for aerosol generating devices having a rechargeable battery than can be replaced at the end of its lifetime. This necessitates a mechanical interface to enable replacement of the battery by the user. The additional connectors, compartments, and mechanical components needed to facilitate battery replacement further increases the size of such aerosol generating devices.

[0007] It is an object of the invention to address these competing demands.

[0008] SUMMARY OF INVENTION

[0009] According to a first aspect of the present invention, there is provided an aerosol generating device, comprising: a heating chamber for receiving an aerosol generating substance and a heater arranged to heat an aerosol generating substance received in the heating chamber; a battery configured to operate at or below a first maximum temperature; and one or more energy storage devices configured to operate at or below a second maximum temperature that is higher than the first maximum temperature; wherein the battery is configured to provide electrical power to at least one of the heater and the one or more energy storage devices, and the one or more energy storage devices are positioned between the battery and the heating chamber.

[0010] In this way, the device can be made more compact without compromising safety. The one or more energy storage devices can safely withstand higher temperatures than the battery and can hence be positioned more closely to the heating chamber, maximising the use of space within the aerosol generating device.

[0011] The energy storage devices can be any suitable type of device for storing electrical energy. For example, the energy storage devices can include one or more supercapacitors and / or one or more batteries. The one or more energy storage devices can thus also be described as one or more “power modules”. The energy storage devices can be connected in series, parallel, or any other suitable configuration, however each of the energy storage devices need not be electrically connected to each other. The one or more energy storage devices can be provided in a single discrete unit or distributed in different locations in the aerosol generating device to maximise use of the available space within the aerosol generating device.

[0012] The energy storage devices can be directly between the battery and the heating chamber or may be separated from the battery or heating chamber by intervening components.

[0013] The battery can comprise a single battery cell or a plurality of battery cells, in which case the battery may also be referred to as a battery unit or module.

[0014] It would be appreciated that the first and second maximum temperatures refer to a maximum operating temperature deemed safe for the particular energy storage device or battery during discharging. The first maximum temperature of the battery may be 60 °C during discharging of the battery, e.g. fora lithium ion battery, and the second maximum temperature would depend on the particular choice of device, but may be 105 °C for a lithium ion supercapacitor or 350 °C for a ceramic solid-state battery. It would be understood by persons skilled in the art that the first and second “maximum” temperatures can be temperatures that should not be exceeded continuously for device safety, but may be exceeded briefly in short thermal peaks. Thus, the battery and the one or more energy storage devices may operate for brief periods above the first maximum temperature and the second maximum temperature, respectively.

[0015] The energy storage devices can comprise one or more energy storage devices of a first type and one or more energy storage devices of a second type, where each type may have different maximum operating temperatures that are nevertheless higher than the first maximum temperature of the battery. The first type may be configured to operate at a higher maximum temperature than the second type, and may be positioned closer to the heating chamber than the second type. In one example, the first type can be a solid-state battery (such as a ceramic solid- state battery), and the second type can be a supercapacitor (such as a lithium ion supercapacitor or “LiC capacitor”). In this way, the use of space can be maximised and, at the same time, the first type can thermally shield the second type.

[0016] The battery can power the heater directly. Alternatively, the battery can be configured to only to recharge the one or more energy storage devices, which can then be configured to provide power to the heater. The heater can also be powered by a combination of the one or more energy storage devices and the battery.

[0017] Preferably, the one or more energy storage devices comprise a supercapacitor configured to provide power to the heater. In this way, an energy storage device is provided that can withstand higher operating temperatures, allowing it to be positioned closer to the heating chamber than the battery. As supercapacitors generally have high discharge rates, this allows the battery to be of a type having a higher energy density, which tend to have lower discharge rates that may be insufficient for powering the heater, at least at some stages of aerosol generation with higher power requirements. Providing a supercapacitor helps to work around a limitation of batteries that causes batteries to have a reduced useful capacity at high discharge rates.

[0018] The supercapacitor can have any suitable size and shape, such as a cylindrical shape, an oval shape, or any other bespoke shape that fits within the aerosol generating device.

[0019] In one example, a single supercapacitor is provided. In other examples, a plurality of supercapacitors can be provided, for instance connected in series.

[0020] In other examples, in place of or in addition to a supercapacitor, any other kind of energy storage device could be provided, preferably one with a high discharge rate such as a lithium-titanate or lithium-titanium-oxide (LTO) battery.

[0021] Preferably, at least one of the one or more energy storage devices are provided adjacent the battery. In this way, the aerosol generating device is more compact. The energy storage device or devices adjacent the battery can be abutting the battery or directly next to the battery, e.g. with a minimal air gap of less than 1 mm or 0.5 mm.

[0022] In general, the term “adjacent” as used herein can be understood to include two components in abutment or positioned next to one another with a minimal air gap, e.g., of less than 1 mm or 0.5 mm.

[0023] Preferably, the at least one energy storage device and the battery are provided together in an integrated unit, without or substantially without mechanical frames or parts separating these two components. In this way, device compactness can be maximised.

[0024] Preferably, at least one of the one or more energy storage devices are separated from the heating chamber by a thermal protection component. In other words, the thermal protection component may be between the heating chamber and some or all of the energy storage devices. In this way, the safety of the aerosol generating device can be improved by avoiding overheating of the one or more energy storage devices or the battery. The thermal protection component can provide thermal protection in the form of a thermal reservoir configured to absorb heat, or thermal insulation configured to inhibit the flow of heat from the heating chamber. The thermal protection component can be of any suitable kind known in the art. In some embodiments, the thermal protection component may be provided adjacent the heating chamber so that all of the energy storage devices are separated from the heating chamber by the thermal protection component. Alternatively, some of the energy storage devices may be between the thermal protection component and the heating chamber.

[0025] The thermal protection component can provide so-called “thermal peak sharing” to reduce the peak temperature experienced by the one or more energy storage devices and / or the battery. The thermal protection component can be any material or component that provides a thermal buffer in this manner, such as a water-based gel, rocks, sand, molten sand, or any other solid or liquid medium.

[0026] Preferably, the thermal protection component comprises a thermal reservoir, which may have a higher heat capacity compared to surrounding components (at least in the range of operating temperatures of the heater) in order to absorb heat from the heating chamber.

[0027] Preferably, the thermal reservoir comprises a phase-change material configured to change phase when heated to an operating temperature of the heater. In this way, a high amount of heat can be absorbed using a relatively small volume of phase-change material. The phase change material can comprise one or more of a hydrated salt, an organic solution, or a solid-state phase change material as known in the art, in some specific examples. Any other suitable material can be provided in other embodiments.

[0028] Preferably, the heating chamber, the one or more energy storage devices, and the thermal protection component are provided adjacent (i.e. , abutting or directly next to) one another, i.e., arranged adjacently in a row. In this way, the aerosol generating device can be made more compact in an elongate aerosol generating device. In the same way, the battery may also be arranged adjacent the one or more energy storage devices or the thermal protection component, e.g., whichever is positioned further from the heating chamber.

[0029] Preferably, at least one of the one or more energy storage devices are positioned adjacent the heating chamber. In this way, the aerosol generating device can be made particularly compact.

[0030] Preferably, the one or more energy storage devices comprise one or more solid- state batteries. Such batteries do not leak, and also are generally resistant to high temperatures and catching fire under impact or short circuit conditions. Therefore, the use of solid-state batteries provides a particularly safe means of maximising the available energy storage capacity of the aerosol generating device. The solid- state batteries are preferably provided closer to the heating chamber than any additional energy storage devices of a different type, and may abut the heating chamber. This allows the solid-state batteries to provide thermal shielding for less temperature-resistant energy storage components.

[0031] Preferably, the one or more solid-state batteries, such as ceramic solid-state batteries, may be positioned adjacent the heating chamber, as this type of energy storage device has a particularly high temperature tolerance.

[0032] Preferably, the one or more solid-state batteries are configured to provide electrical power to one or more components of the aerosol generating device that require less power than the heater. In this way, the solid-state batteries can supply power to various lower power components even while the battery is depleted. In one example, the solid-state batteries are configured to provide power to a wireless interface, or an LED to enable a charge state of the battery to be communicated to the user.

[0033] Preferably, the one or more solid-state batteries comprise ceramic. In this way, the solid-state batteries are of a type and material that is particularly temperature resistant.

[0034] Preferably, the one or more solid-state batteries are connected to a temperature resistant PCBA. Where a plurality of solid-state batteries are provided, these may be arranged at a plurality of spaced positions adjacent the heating chamber to maximise the use of space in the aerosol generating device.

[0035] Preferably, the battery is of a type having an energy density higher than that of a lithium-ion battery, such a zinc-air battery, aluminium-air battery, or lithium-air battery. In addition, preferably the one or more energy storage devices includes at least one device with a maximum power output greater than the battery, which may correspond to providing an output current of 2 Amperes. In this way, the battery can have a higher energy density, which enables a more compact device and / or a greater energy capacity. A zinc-air battery may be used in a particularly preferred embodiment, as this type of battery is particularly energy dense, environmentally friendly, low-cost, and has a long lifetime.

[0036] Preferably, at least one of the energy storage devices has a maximum power output that is greater than that of the battery and is configured to provide power to the heater. In this way, the battery can be of a type having a higher energy density because the power requirements of the heater are serviced by the at least one of the energy storage devices. This allows the battery to store energy for more aerosol generation sessions, or, alternatively, to be of a smaller size without compromising maximum energy capacity. The at least one energy storage device can be a supercapacitor or a battery with a high power output, such as an LTO battery, in some examples. The term “maximum power output” can also be described as a “discharge rate”.

[0037] Preferably, the heater is configured to operate at a temperature suitable for generating an aerosol from an aerosol generating material comprising tobacco, where the temperature is below the combustion temperature of tobacco. In this way, the aerosol generating device can function a heat-not-burn device. In particular, when the device is configured to be used as a heat-not-burn device, the one or more energy storage components preferably include a component having a higher power output than the battery. Providing such a component helps to work around a limitation of batteries that causes batteries to have a reduced useful capacity at high discharge rates, which are usually needed to heat tobacco without burning it. Therefore, the increased compactness or effective energy capacity increase that can be attained by the provision of the energy storage devices may be greater.

[0038] Preferably, the heating chamber and heater are provided in a heating system comprising insulation, such as a vacuum chamber surrounding the heating chamber. In this way, remaining components of the aerosol generating device can be thermally shielded.

[0039] Preferably, the aerosol generating device is elongate along a longitudinal axis, and the battery, heating chamber and one or more energy storage devices are arranged at different positions along the longitudinal axis. This arrangement has been found to be compact and compatible with existing designs.

[0040] Preferably, the aerosol generating device comprises a charging interface configured to receive electrical current from an external power supply to charge the battery. The charging interface can be any suitable kind of standardised connection, such as USB or USB-C interface, or any suitable kind of bespoke connection.

[0041] The aerosol generating device may include a temperature sensor configured to measure a temperature of the battery. The aerosol generating device may be configured to inhibit or restrict charging of the battery when the battery is above a threshold temperature. In this way, the safety of the device can be improved. In one example, a controller of the device may be configured to inhibit or restrict the charging. Restricted charging may involve enabling charging with a lower current value to avoid overheating of the battery. The threshold temperature may be 45 °C, for instance when the battery is a lithium ion battery.

[0042] Preferably, the battery is arranged in a battery seating configured to enable removable of the battery from the aerosol generating device. The seating can be accessible through a hinged door, in one example. This facilitates replacement of the battery at the end of its lifetime. Preferably, at least one of the one or more energy storage devices are configured to provide power to a component of the aerosol generating device while the battery is unable to provide power to the component, for instance because it has been removed from the battery seating, has malfunctioned, or is depleted. In this way, at least some functionality of the aerosol generating device can be maintained even if the battery is not able to provide power to the component. The one or more energy storage devices can be configured to provide power to control components of the aerosol generating device, such as a controller, or input / output devices such as an airflow sensor or LEDs. In one example, the supercapacitor may be configured to provide power to the controller when the battery is unable to do so. The solid-state batteries may be configured to provide power to other components, such as input or output devices of the aerosol generating device.

[0043] The one or more energy storage devices may be configured to provide power to a controller of the aerosol generating device when the battery is depleted but connected to an external power source by the charging interface. This can enable aerosol generation using energy supplied by the external supply, even though the battery itself is depleted, because the one or more charge storage devices can supply power to the control components. In one example, the supercapacitor may be configured to provide power to the controller. The aerosol generating device may be configured to enable the external power source to provide power directly to the heater even when the battery is removed from the device.

[0044] BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 shows a schematic perspective diagram of a known aerosol generating device;

[0046] Figure 2 shows a schematic perspective diagram of a portion of a known aerosol generating device;

[0047] Figure 3 shows a schematic perspective diagram of a portion of a known aerosol generating device; Figure 4 shows a schematic perspective diagram of a portion of a known aerosol generating device;

[0048] Figure 5 shows a schematic cross-sectional diagram of a portion of a known aerosol generating device;

[0049] Figure 6 shows a schematic cross-sectional diagram of an aerosol generating device according to an embodiment of the invention;

[0050] Figure 7 shows a schematic cross-sectional diagram of a portion of an aerosol generating device according to an embodiment of the invention;

[0051] Figure 8 shows a schematic cross-sectional diagram of a portion of an aerosol generating device according to an embodiment of the invention;

[0052] Figure 9 shows a schematic cross-sectional diagram of a portion of an aerosol generating device according to an embodiment of the invention;

[0053] Figure 10 shows a schematic cross-sectional diagram of a portion of an aerosol generating device according to an embodiment of the invention;

[0054] Figure 11 shows a schematic cross-sectional diagram of a solid-state battery that can be used in an aerosol generating device according to an embodiment of the invention;

[0055] Figure 12 shows a schematic cross-sectional diagram of a portion of an aerosol generating device according to an embodiment of the invention; and

[0056] Figure 13 shows a circuit diagram of a power and heating system of an aerosol generating device according to an embodiment of the invention.

[0057] DETAILED DESCRIPTION

[0058] Figure 1 shows a schematic perspective diagram of an exemplary known aerosol generating device 1 highlighting one issue that can be improved by the present invention. The known aerosol generating device 1 comprises a heating system 2 and a battery 4 spaced apart by an air gap 6. The heating system 2 and battery 4 are arranged along a longitudinal axis of the aerosol generating device 1 . The battery 4 provides electrical power to a heater (not shown) of the heating system 2. Although insulation is provided in the heating system 2, heat eventually disperses from the heating system 2 by conduction. The air gap 6 provides an insulating layer that further impedes the flow of heat to the battery 4 to ensure the battery 4 is maintained below a maximum safe operating temperature.

[0059] Figures 2 to 4 show schematic diagrams from different perspective views of a lower portion of the heating system 2 and an upper portion of the battery 4 near the air gap 6. Figure 5 shows a schematic cross-sectional diagram of the same parts of the aerosol generating device 1.

[0060] The heating system 2 comprises an outer wall 2a and an inner wall 2b. The inner wall 2b defines an internal heating chamber where an aerosol generating substance can be received and heated by a heater (not shown) of the heating system 2. Insulation is provided between the outer wall 2a and the inner wall 2b. An annular recessed portion 2c is provided on the lower end of the heating system 2 between the inner and outer walls 2b, 2a.

[0061] As shown in Figure 5, the inner wall 2b defines the heating chamber. The inner wall 2b protrudes past a lower edge of the outer wall 2a.

[0062] Reducing or eliminating the presence of the air gap 6 would further miniaturise the aerosol generating device 1 but could cause the battery 4 to reach unsafe temperatures during use. On the other hand, increasing the size of the battery 4 would enable the aerosol generation device 1 to require charging less often but would increase size of the device 1 .

[0063] Figure 6 shows a cross-sectional schematic diagram of an aerosol generating device 100 according to an embodiment of the invention.

[0064] As shown, the aerosol generating device 100 comprises a heating system 102, a phase-change material 104, a supercapacitor 106, and a battery 108 arranged adjacent and abutting one another. The heating system 102 comprises an outer wall 110 and an inner wall 112, between which a vacuum 114 is enclosed. The inner face of the inner wall 112 defines a cavity that acts as a heating chamber 116 for receiving an aerosol generating material. A resistive heater 118 is positioned on an outer face of the inner wall 112, within the vacuum 114, for heating an aerosol generating substance received in the heating chamber 116.

[0065] The aerosol generating device 100 further comprises a housing for containing and protecting the other components of the device, which is not shown in Figure 6 for the purposes of illustration. A controller (not shown) and memory (not shown) can also be provided within the housing for executing and storing, respectively, instructions for operating the aerosol generating device 100. Any suitable input mechanism, such as a button or airflow sensor, can be provided to initiate the heater 118.

[0066] In this example the aerosol generating device 100 further comprises a battery seating (not shown) for enabling the battery 108 to be replaced. A temperature sensor (not shown) can also be provided for monitoring the temperature of the battery 108 and preventing or inhibiting recharging of the battery 108 when the battery 108 is above a threshold temperature.

[0067] The heating system 102 can be of any other suitable type or construction known in the art. For example, the heater 118 could be provided on an inner face of the inner wall 112, or could be replaced with an induction coil for heating an inductive element located inside the heating chamber 116 or in a consumable comprising an aerosol generating substance. Similarly, the vacuum 114 (i.e., a region that has been at least partially evacuated to a lower pressure than ambient air pressure) can be replaced with any other suitable type of insulation.

[0068] In this example, the inner and outer walls 110, 112 are cylindrical, so that the heating chamber 116 is a cylindrical cavity and the heating system 102 is an annular unit with a closed lower end and an open upper end. It would be appreciated that the heating chamber 116 and surrounding insulation can have any other suitable construction known in the art. In this example, the heating system 102 is configured to receive a consumable comprising tobacco in the heating chamber 116 and heat the consumable to temperatures below the combustion temperature of tobacco. The tobacco may be provided in stick, e.g., having a circular or rectangular cross-sectional shape to match that of the heating chamber 116. However, the heating system 102 can be configured to heat any other type of aerosol generating substance known in the art.

[0069] The phase-change material 104 has a high thermal mass and is configured to undergo a phase-change when heated from room temperature to an operating temperature of the heater 118. This reduces the amount of heat that can reach the supercapacitor 106 and the battery 108 during use of the aerosol generating device 100, reducing their maximum temperature reached during operation. The phase change material 104 can comprise one or more of a hydrated salt, an organic solution, or a solid-state phase change material. Any other suitable material can be provided in other examples. The phase-change material 104 may be stored in a suitable sealed container. In other examples, any other type of thermal protection component (e.g., an insulation layer or air gap, or an alternative kind of thermal reservoir) can be provided in place of or in addition to the phase change material 104.

[0070] The supercapacitor 106 stores electrical charge that is used to power the heater 118, in this example. The supercapacitor 106 can be recharged by the battery 108 between uses of the aerosol generating device 100 and while the heater 118 is operating, e.g., during an off-phase of the heater’s duty cycle, discussed further below. In other embodiments, the battery 108 can be used to power the heater 118 in addition to the supercapacitor 106, but in this example is used primarily to recharge the supercapacitor 106, which solely provides power to the heater 118.

[0071] The supercapacitor 106 in this example is permanently located in the aerosol generating device 100 and is rechargeable using the battery 108. Alternatively, the supercapacitor 106 can be removable and / or replaceable through a suitable openable supercapacitor seating. The supercapacitor 106 can be a hybrid supercapacitor such as a LiC supercapacitor and could be recharged externally from the aerosol generating device 100.

[0072] The supercapacitor 106 is substantially cylindrical in this example. However, any other shape configured to fit compactly within the overall assembly of the aerosol generating device 100 can be implemented. In an alternative example, the supercapacitor 106 can have an oval shape.

[0073] Any other type of energy storage device having a higher maximum operating temperature than the battery 108 can be provided instead of or in addition to the supercapacitor 106. In one example, a lithium-titanate (LTO) battery can be used instead. The supercapacitor 106 is a lithium-ion supercapacitor in this example but can be of any other suitable kind of supercapacitor in other examples of the invention. Only a single supercapacitor 106 is provided in the exemplary aerosol generating device 100. However, in other examples a plurality of supercapacitors could be provided, which may be connected in series.

[0074] The battery 108 is a lithium ion battery in this example. However, the battery 108 can be of any other kind in other examples, such as a zinc-air, lithium air, or aluminium air battery. The battery 108 may be permanently located in the aerosol generating device 100 and rechargeable through a standardised charging port provided on an external portion of the aerosol generating device 100. Alternatively, the battery 108 could be removable and / or replaceable through a suitable openable battery seating.

[0075] The battery 108 comprises a plurality of cells arranged in a YsXp configuration, for positive integer values of Y and X, configured to provide or operate at 5 V, in this example. The term “Ys” in YsXp refers to the number of battery cells (or number of sets of parallel battery cells if X is greater than 1) connected in series, and increases the voltage provided by the battery compared to a single cell by a factor of Y. The term “Xp” in 2sXp refers to the number of cells connected in parallel provided in each set. Larger numbers of cells connected in parallel effectively increase the capacity of the battery overall. In this example, the battery 108 comprises 8 cells in a 2s4p configuration, but could comprise a single cell or multiple cells in any other YsXp configuration, configured to operate at 5V or otherwise, in other embodiments.

[0076] As there can be an inverse relationship between energy density and maximum discharge current in some types of batteries, it may be desirable to provide the battery 108 with a low maximum discharge current. The higher power requirements of the heater 118 can be accommodated by the supercapacitor 106. In general, the battery 108 may have a maximum discharge current of 2 Amperes in order to maximise the amount of energy stored while meeting other demands of the aerosol generating device 100.

[0077] The heater 118 is a thin film heater that generates heat due to its electrical resistance, in response to an applied current. The heater 118 is wrapped about the outer face of the inner wall 112 and is electrically connected to the supercapacitor 106 by a suitable connection (not shown). In other examples, the heater 118 can be arranged in various other ways or be of various other kinds known in the art.

[0078] To operate the aerosol generating device 100, a user can insert a consumable such as a tobacco stick into the cavity 116 through the open end of the heating system 102. A button or other input mechanism can be used by the user to initiate the vaping session. The controller instructs the heater 118 to heat to a pre-defined aerosol generating temperature. The tobacco stick is heated, generating an aerosol which can be inhaled by the user through a protruding end of the stick. The vacuum 114 inhibits the flow of heat from the cavity 116 to other parts of the aerosol generating device 100. Heat nevertheless flows by conduction to the phase change material 104. The phase change material 104 absorbs heat from the heater 118 and increases in temperature until it reaches a phase change temperature. At this point, the phase change material continues to absorb heat, but remains at the phase change temperature until the material has changed phase. This provides thermal protection to the supercapacitor 106 and the battery 108. The heater 118 can be operated using duty cycles. In general, a duty cycle comprises an on-phase and an off-phase that occur in sequence. The combined duration of the on- and off-phases represents a single cycle. A particular duty cycle can be expressed as a percentage or fraction of the time in each cycle spent in the on-phase. This allows a binary state heater to provide different amounts of heating, by increasing or decreasing the proportion in each cycle spent in the on- phase.

[0079] The aerosol generating device 100 can be configured to operate in different modes, such as a pre-heating mode having a high duty cycle, used to increase the temperature of the heater 118 to a predetermined aerosol generation temperature. A floating-mode having a low duty cycle (i.e., lower than that of the pre-heating mode) can be used to maintain the temperature of the heater 118 at the pre-determined temperature.

[0080] The pulse width modulated power flow in the float mode operates with a first duty cycle regime that comprises one or more pulse width modulation (PWM) cycles with a first duty cycle ratio D1. In the preheating mode, the supercapacitor 106 powers the heater 118 with a pulse width modulated power flow with a second duty cycle regime that comprises one or more PWM cycles with a second duty cycle ratio D2. The relationship between D1 and D2 can be considered as D2 = D1*K, where K is a coefficient that is » 1 and can be selected as an implementation choice. In an example, the first duty cycle ratio can be much less than 1 , and the second duty cycle ratio can be close to but less than 1 . In other examples, the first duty cycle ratio can be « 0.5 and the second duty cycle ratio can be > 0.5. In further examples, the first duty cycle is configured such that < 3 W is applied in the float mode, and the second duty cycle is configured such that approximately 16 W is applied in the preheating mode.

[0081] In each case, while the heater 118 is in an on-phase of the duty cycle, the supercapacitor 106 can discharge to supply power to the heater 118. During an off-phase of the duty cycle, the supercapacitor 106 may be re-charged by the battery 108. This method of operation can be useful as it enables a smaller supercapacitor to be provided, since the supercapacitor does necessarily have to have an energy capacity to accommodate an entire phase of heating. This mode of operation is described in more detail with respect to Figure 13 below, which shows one exemplary circuit that can implement this functionality. It should be noted that in other embodiments, the supercapacitor 106 need not be recharged during an off-phase of the heater’s duty cycle in this way. For instance, the supercapacitor 106 could have a larger energy capacity that enables it to supply power to the heater 118 for a prolonged period, such as for the whole pre-heating mode, without being recharged.

[0082] Figure 7 shows a cross-sectional schematic diagram of a portion of the aerosol generating device 100 between the heating system 102 and the battery 108.

[0083] Instead of the air gap 6 present in the known aerosol generating device 1 , the phase change material 104 and the supercapacitor 106 occupy the space between the heating system 102 and the battery 108 in the aerosol generating device 100. The supercapacitor 106 can operate safely at a higher maximum temperature than the battery 108. This allows the supercapacitor 106 to be positioned more closely to the heating system 102 without posing a safety risk, thereby providing a more compact arrangement.

[0084] The phase change material 104 is positioned abutting the heating system 102, occupying the space corresponding to the annular recess 2c in the aerosol generating device 1 . The phase change material 104 also comprises a connected thin layer 120 below the transverse face of the inner wall 112. This forms an overall disk shape with a circular recess to accommodate the transverse face of the inner wall 112, though the phase change material 104 can have any other suitable shape and construction in other examples. The phase change material 104 is radially spaced from the inner wall 112 to provide a radial air gap 122 surrounding the lowermost part of the inner wall 112, which impedes the flow of heat from the heating chamber 116 to the phase change material 104.

[0085] In Figure 7, the height (i.e. vertical dimension from the perspective shown) of the supercapacitor 106 is preferably 5 mm or less and has a diameter that is at least smaller than the inner diameter of the housing of the aerosol generating device 100. The diameter is preferably similar to that of the battery 108.

[0086] Details regarding the usefulness of the supercapacitor 106 are as follows.

[0087] In an aerosol generation session for heating but not burning tobacco, power required by the heater 118 is generally greater during the initial stage (“pre-heating stage”) of the session (for heating up the tobacco substrate). The power required during the session (between consecutive puffs) to maintain the temperature of the heater 118 tends to be significantly lower.

[0088] The average power during the initial stage may be 10-20 W (e.g. , 15 W), while the average power during the session is 1-10 W (e.g., 5W). However, at the earliest parts of the initial pre-heating stage, the power required by the heater may be even higher than 10-20 W, such as in the range of 20-40 W (e.g., 30 W). In the conventional system 1 without a supercapacitor, the discharge current (discharge rate) of the battery 4 during the initial stage may increase significantly. The high discharge current during the initial session causes the reduction of the “capacity retention” of the battery. The capacity retention is the proportion of electrical energy that can be extracted under the conditions of discharge until a given threshold, e.g., a minimum battery voltage of 2.7 V. Therefore, as the power required by the heater during the initial pre-heating stages in heat-not-burn devices is particularly high compared to other types of devices, these factors place a more significant strain on the batteries of heat-not-burn devices. Heating temperatures in these devices also tend to be higher for prolonged periods, creating further demands regarding thermal management.

[0089] Powering the heater 118 by discharging of the supercapacitor 106 avoids this high discharge current of the battery 108. This, in turn, prevents the undesirable reduction of the capacity of the battery 108 and the available or useful capacity of the battery 108 increases. The energy density of the battery 108 effectively increases and thus its volume may be reduced compared to the case where the battery 4 is not combined with a supercapacitor. This is particularly advantageous for devices requiring high power heating, such as heat-not-burn devices. This benefit of the supercapacitor 106 becomes more pronounced when the battery 108 is depleted or operated at low temperatures (e.g., 0°C), where the internal resistance of the battery 108 may increase. For example, when the battery 4 becomes depleted, it can suffer from a reduced discharge rate that can be insufficient for powering the heater. Specifically, at low charge levels the opencircuit voltage of the battery 4 drops and its internal resistance increases. This means that current requested by the heater to deliver same power gets higher and the voltage drops lower. This leads to reaching a minimum voltage threshold even when there is enough energy in the battery 4 to support a full aerosol generation session, but not enough power. This issue is exacerbated by the particularly high power required at the earliest stages of pre-heating, where the maximum power required can be 20-40W. In this context, supercapacitor 106 of the present invention, which has a higher discharge rate, helps to work around the limitation of the battery 108 in terms of reduced useful or available capacity at high discharge rates, so that the available or useful battery capacity increases. This enables the battery 108 to be smaller than the battery 4 while providing an equivalent usable capacity, or can be of the same size while providing an increased usable capacity.

[0090] Additionally, because the supercapacitor 106 has a higher discharge rate than the battery 108, the battery 108 can be provided with a higher energy density (which generally comes with the cost of a lower discharge rate).

[0091] Thus, the supercapacitor 106 effectively increases the available or useful battery capacity and provides a more consistent high discharge rate that enables the battery 108 to be more energy-dense. Together, it has been found these factors mean the battery 108 can be significantly smaller compared to the battery 4 while supporting the same number of aerosol generation sessions (“vaping sessions”).

[0092] These advantages have been described with respect to a supercapacitor. However, it would also be possible to achieve similar advantages with other types of energy storage devices having a higher discharge rate than the battery 108. The extent of the volume reduction attainable in a particular embodiment can depend on different factors, e.g., the power requirements during pre-heating as discussed above, or the chemistry of the battery 108. Settings of control functions can also influence the volume reduction achievable by providing the supercapacitor 106. Functions that prevent initiating an aerosol generation session when there is insufficient (usable) energy remaining in the battery are one example. As the provision of the supercapacitor 106 effectively increases the usable or useful energy capacity of the battery 108, the threshold for ensuring there is sufficient energy in the battery 108 for full consumption of at least one consumable can be lowered compared to the aerosol generating device 1. Depending on the pre-heating power requirements and the settings of other control functions, the battery 108 can have potentially up to 30% less volume (e.g., be 30% shorter) than the battery 4. However, it would be appreciated that the volume reduction achieved would vary between different implementations depending on various factors such as the type of aerosol generating device, consumable, battery, and / or supercapacitor selected.

[0093] Returning to the arrangement of Figure 7, in this example, the phase change material 104 comprises a thin layer 120 that separates the transverse face of the inner wall 110 from the supercapacitor 106 to provide thermal protection. The layer 120 is about 1 mm in this example. In other examples, the layer may be about 0.5 mm to 5 mm. As the layer 120 and the supercapacitor 106 occupy a space that was previously an air gap and because the battery 108 can be made smaller in height than the battery 4, the aerosol generating device 100 has a height that is smaller than that of the aerosol generating device 1 .

[0094] It would be appreciated that in other embodiments this arrangement could be leveraged to provide the aerosol generating device 100 with the same height as the aerosol generating device 1 but greater charge capacity. That is, the larger battery 4 could be used in conjunction with the supercapacitor 106 and the phase change material 104 to increase the amount of (usable) energy that can be stored without increasing the overall height of the aerosol generating device 100. In the aerosol generating device 1 , a full battery charge may be sufficient for consumption of about 20 tobacco stick consumables. Therefore, providing potentially up to 30% increased usable capacity (for example) may be sufficient to power the heater 118 for the aerosolization of up to six additional consumables.

[0095] It would be understood that the exemplary savings in device size are approximate and based on one exemplary type of device. Persons skilled in the art would appreciate that a greater or lesser reduction of size may be achieved in other embodiments according to the particular implementation.

[0096] As shown in Figure 8, in a further example the supercapacitor 106 can also have a larger height of about 6 mm to about 10 mm, such as about 8 mm, to provide an increased capacity, if required.

[0097] To further miniaturise the aerosol generating device 100, the supercapacitor 106 and the battery 108 may be integrated together in a single unit without plastic, foam, or other protective components positioned therebetween. This can further reduce the height of the aerosol generating device 100 or enable an increase of the size of the battery (without increasing the overall device height).

[0098] The battery 108 is a lithium ion battery in this example. However, because the supercapacitor 106 can provide a sufficient power output to power the heater 118, the power requirements of the battery 108 are reduced compared to the aerosol generating device 1. This allows the battery 108 to be of a type with a higher energy density than lithium ion batteries, such as Zinc-air, which typically have lower power outputs compared to lithium ion batteries that would be insufficient to power the heater 118. This allows the aerosol generating device 100 to be made even more compact.

[0099] Figure 9 shows a schematic cross-sectional view of an alternative embodiment of the aerosol generating device 100 comprising a plurality of ceramic solid-state batteries 124 mounted to a temperature-resistant printed circuit board assembly (PCBA) 126. Figure 10 shows an alternative cross-sectional view of the solid- state batteries 124, for a cross section taken perpendicularly to the longitudinal axis of the aerosol generating device 100. The solid-state batteries 124 are provided abutting the heating system 102 instead of the phase change material 104. The PCBA 126 is provided abutting the supercapacitor 106. Otherwise, the aerosol generating device of Figure 9 is as described previously. The solid-state batteries 124 can operate safely at a higher temperature compared to the battery 108 and can therefore be positioned closer to the heating system 102 without posing a safety risk. The solid-state batteries 124 and PCBA 126 at least partially shield the supercapacitor 106 and the battery 108 from heat during use.

[0100] The solid-state batteries 124 are configured, in this example, to supply energy to low-power components of the aerosol generating device 100 (i.e., components requiring less power than the heater 118). For example, the solid-state batteries 124 can be configured to provide power to LEDs on an external surface of the aerosol generating device 100, and / or to a wireless interface, so that subsidiary functionality of the aerosol generating device 100 can be maintained even if the main battery 108 is depleted. This can be useful for various purposes, such as indicating a low charge state even when the battery 108 is completely depleted or removed. The solid-state batteries 124 are provided in a region corresponding to an air gap in the aerosol generating device 1 (specifically, the recess 2c). This maximises the use of the space surrounding the inner wall 112 so that the functionality of the solid-state batteries 124 can be obtained without significantly increasing the size of the aerosol generating device 100.

[0101] It would be appreciated that in other embodiments the solid-state batteries 124 could be provided in other regions of otherwise “dead space” near a heating system of aerosol generating devices having a different structure.

[0102] In the example of Figure 10, four equally sized solid-state batteries 124 are provided at four evenly spaced positions surrounding the inner wall 112 to maximise the use of space in the aerosol generating device 100.

[0103] In this specific example, the solid-state batteries 124 can have the properties listed in columns A or B of the Table 1 below, however it would be appreciated that in other examples the solid-state batteries 124 these properties can have other values:

[0104] 1 second.

[0105] Figure 11 shows a schematic diagram of one of the solid-state batteries 124 of Figures 9 and 10. Each solid-state battery 124 comprises a ceramic base 130 containing electrodes 132. A lid 134 covers the ceramic base 130 and is welded to the ceramic base 130 in a weld area 136. The lid 134 is attached to the ceramic base 130 by a metal seal 138. The metal seal 138 may hermetically seal the electrodes 132 within the ceramic base 130. Solid-state batteries of this construction have been found to safely withstand temperatures of about 350 °C, meaning they can be positioned safely near or directly abutting the heating system 102.

[0106] In other embodiments, the solid-state batteries 124 can be of any other suitable shape or construction known in the art and may comprise materials other than ceramic. For instance, a single annular solid-state battery could be provided in the space corresponding to the recess 2c of the aerosol generating device 1 to maximise the use of space between the heating system 102 and the battery 108.

[0107] The PCBA 126 in this example is temperature-resistant (i.e. , can at least withstand a higher temperature than the battery 108) and can be of any suitable type or construction known in the art. However, in other embodiments, the PCBA 126 may not be temperature resistant, for instance if separated from the heating system 102 by a sufficient thermal protection component or layer.

[0108] The aerosol generating device 100 may comprise both solid-state batteries 124 and the phase change material 104 in other embodiments. For instance, the phase change material 104 could be positioned to separate the solid-state batteries 124 from the heating system 102.

[0109] Further solid-state batteries can also be provided surrounding the lowermost end of the inner wall 112. Figure 12 shows one such example, where three smaller solid-state batteries of type A of Table 1 are clustered on each of two opposing sides of the inner wall 112 (forming a total of six smaller solid-state batteries). Two larger solid-state batteries of type B of Table 1 are provided on opposing sides of the inner wall 112, between each cluster of smaller solid-state batteries. This arrangement may increase the utilisation of space compared to the arrangement of Figure 10. In other examples, further or fewer solid-state batteries 124 can be provided in any suitable arrangement.

[0110] Figure 13 shows a circuit diagram of an exemplary circuit containing the battery 108, the supercapacitor 106, the solid-state batteries 124, the heater 118 and various other components that provide a power and heating system 200 for the aerosol generating device 100. The solid-state batteries 124, the battery 108, the supercapacitor 106, and the heater 118 are connected in parallel between a main power line (P) and ground.

[0111] As shown, the circuit comprises a main switch SW1 for enabling or inhibiting current flow from a main charging source, e.g., from a standardised charging interface connection such as USB, USB-C, or any other suitable interface. The switch SW1 can be in an on-state when the aerosol generating device 100 is connected to the main charging source to charge the battery 108. Remaining switches may be in an off-state, so that only the battery 108 receives charging from the main charging source. In this case, the battery 108 is used to later recharge the solid-state batteries 124 and the supercapacitor 106. Alternatively, other switches may be in an on-state at the same time as SW1 to charge other components using the main charging source simultaneously. However, even in this case, the battery 108 can be used later to recharge the solid-state batteries 124 and the supercapacitor 106 once the aerosol generating device 100 is disconnected from the main charging source.

[0112] A switch SW2 is provided to enable or disable current flow to the solid-state batteries 124. The solid-state batteries 124 are connected in parallel between the switch SW2 and ground. Only three individual solid-state batteries are shown in Figure 13 for the purposes of illustration, however it would be appreciated that four batteries (as shown in Figure 10), eight batteries (as shown in Figure 12), a single solid-state battery, or any other suitable number of solid-state batteries can be connected in this way in the system 200.

[0113] A switch SW3 is provided to enable or disable current flow to the battery 108 from the main power line P.

[0114] A first DC to DC voltage converter (DC / DC 1) separates the supercapacitor 106 from the battery 108 at the main power line P. DC / DC1 is arranged to step up the voltage from the battery 108 in order to charge the supercapacitor 106 using the battery 108. DC / DC1 may provide an output current limit of 0.5 A to 4.0 A. Charging of the supercapacitor 106 may only be performed in certain situations, such as when not connected to the main charging source and during an off-stage of a duty cycle of the heater 118.

[0115] A switch SW4 is provided to enable or disable current flow from the supercapacitor 106. Switch SW4 can be in an on-state when the supercapacitor 106 is powering the heater 118 or when the supercapacitor 106 is being recharged by the battery 108.

[0116] A second DC to DC voltage converter (DC / DC 2) separates the supercapacitor 106 from the heater 118. DC / DC 2 is arranged to step up the voltage from the supercapacitor 106 in order to power the heater 118 during use. DC / DC 2 may provide a boost converter of a minimum input voltage of 1 .8 V.

[0117] A switch SW5 separates the supercapacitor 106 and the heater 118 at the main power line P, which enables the heater 118 to be enabled or disabled independently. For instance, SW5 may be in an off-state while the aerosol generating device 100 is connected to the main charging source, for safety purposes.

[0118] Switches SW1 , SW2, SW3, SW4, and SW5 can be physical switches, digital switches (e.g., transistors), or any other suitable kind of switching component. In the example power system 200, the switches SW1-SW5 are transistors, which may be connected to a main controller of the aerosol generating device 100 or a dedicated microcontroller. It would be appreciated that the system 200 can comprise various other components, such as a clock, or a processor containing a clock, to provide a timing system for controlling the heater’s duty cycle.

[0119] The solid-state batteries 124 are, for the purposes of illustration, connected only between ground and the main power line P in Figure 13. In practice, the solid- state batteries 124 can be connected to various other components of the aerosol generating device 100. Specifically, the solid-state batteries 124 can be connected to various components requiring less power than the heater 118, such as LEDs, a wireless interface, a controller or processor, or any other suitable component. This enables the low-power components to be operated even when the battery 108 is completely depleted or removed from the aerosol generating device 100. In other examples, however, the solid-state batteries 124 may provide sufficient capacity and power to assist with powering the heater 118 or the capacitor 104. The low-power components may be connected to the solid-state batteries 124 so that even when switch SW2 is in an off-state the low-power components receive power from the solid-state batteries 124.

[0120] During an aerosol generation session, switches SW3-SW5 may switch rapidly between configurations. The supercapacitor 106 can supply power to the heater 118 during an on-phase of the heater’s duty cycle and the supercapacitor 106 may receive charging from the battery 108 during an off-phase of the heater’s duty cycle. In the on-phase, switches SW4 and SW5 may be in an on-state, so that the supercapacitor 106 discharges, providing power and current flow to the heater 118. Switch SW3 can be in an off-state to prevent current flow from the battery 108 to the heater 118. In the off-phase, switches SW3 and SW4 may be in an on- state so that the battery 108 recharges the supercapacitor 106. At the same time, SW5 may be in an off-state so that the battery 108 does not supply power to the heater 118.

[0121] Persons skilled in the art would appreciate that other switching systems and regimes for implementing the duty cycle of the heater, or operating the heater in other ways or modes, could be implemented. For instance, a battery-depleted mode could be implemented that allows a power bank or other external power supply connected at the main power line P to act as the battery 108. In this case, SW1 may be turned on or off according to the specific phase of the heater’s duty cycle 118, instead of switch SW3. In another example, the supercapacitor 106 may be used primarily for a pre-heating phase that requires a greater amount of power, during which the temperature of the heater 118 is elevated to an aerosol generating temperature. In this case, the battery 108 may be used to power the heater 108 for the remainder of the aerosol generation session to maintain the elevated temperature, which requires less power.

[0122] When the battery 108 is unable to provide power to various components of the aerosol generating device 100, such as the controller or other control components, the solid state batteries 124 or the supercapacitor 106 can be configured to provide power to those components. This can be used when the battery 108 has malfunctioned, is depleted, or has been removed from the battery seating to maintain device functionality. In these cases, switches SW2 and SW4 can be set to an on-state accordingly.

[0123] A controller of the circuit 200 can monitor the temperature of the battery 108 using a temperature sensor and prevent charging, or reduce the charging current, when the battery 108 is above a threshold safe charging temperature. Reduction in the charge current may be implemented by a suitable current-limiting component. Persons skilled in the art would appreciate that the power and heating system 200 could be implemented using various different voltage and current schemes as required by the particular selection of components.

Claims

CLAIMS1. An aerosol generating device, comprising: a heating chamber for receiving an aerosol generating substance and a heater arranged to heat an aerosol generating substance received in the heating chamber; a battery configured to operate at or below a first maximum temperature; and one or more energy storage devices configured to operate at or below a second maximum temperature that is higher than the first maximum temperature; wherein the battery is configured to provide electrical power to at least one of the heater and the one or more energy storage devices, and the one or more energy storage devices are positioned between the battery and the heating chamber.

2. The aerosol generating device of claim 1 , wherein the one or more energy storage devices comprise a supercapacitor configured to provide power to the heater.

3. The aerosol generating device of claim 1 or claim 2, wherein at least one of the one or more energy storage devices are provided adjacent the battery.

4. The aerosol generating device of any of the preceding claims, wherein at least one of the one or more energy storage devices are separated from the heating chamber by a thermal protection component.

5. The aerosol generating device of claim 4, wherein the thermal protection component comprises a thermal reservoir.

6. The aerosol generating device of claim 5, wherein the thermal reservoir comprises a phase-change material configured to change phase when heated to an operating temperature of the heater.

7. The aerosol generating device of any of claims 4 to 6, wherein the heating chamber, the one or more energy storage devices, and the thermal protection component are provided adjacent one another.

8. The aerosol generating device of any of the preceding claims, wherein at least one of the one or more energy storage devices are positioned adjacent the heating chamber.

9. The aerosol generating device of any of the preceding claims, wherein the one or more energy storage devices comprise one or more solid-state batteries.

10. The aerosol generating device of claim 9, wherein the one or more solid- state batteries are configured to provide electrical power to one or more components of the aerosol generating device that require less power than the heater.11 . The aerosol generating device of claim 9 or claim 10, wherein the one or more solid-state batteries comprise ceramic.

12. The aerosol generating device of any of the preceding claims, wherein the battery is of a type having an energy density higher than that of a lithium-ion battery, such a zinc-air battery, aluminium-air battery, or lithium-air battery.

13. The aerosol generating device of any of the preceding claims, wherein at least one of the energy storage devices has a maximum power output that is greater than that of the battery and is configured to provide power to the heater.

14. The aerosol generating device of any of the preceding claims, wherein at least one of the one or more energy storage devices are configured to provide power to a component of the aerosol generating device when the battery is unable to provide power to the component.

15. The aerosol generating device of any of the preceding claims, wherein the aerosol generating device is elongate along a longitudinal axis, and thebattery, heating chamber and one or more energy storage devices are arranged at different positions along the longitudinal axis.

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