WO2024146900A1 - Aerosol generating device - Google Patents

Abstract

An aerosol generating device is disclosed and comprises: a first air inlet (118), an air outlet (122), and an air channel (A) configured to fluidically connect the first air inlet and the air outlet; a first electrode (108) and a second electrode (110), configured to generate an electric current through a consumable (10) comprising an aerosol generating substance; a cavity (112) positioned in the air channel and in a layer between the first electrode and the second electrode, the cavity configured to receive the consumable; a first protrusion (114) provided on the first electrode, arranged to protrude into the cavity and configured to pierce an external surface (S) of the consumable when the consumable is received within the cavity; wherein the first electrode comprises a first hole (116) provided at the first protrusion and the air channel is configured to fluidically connect the first air inlet to the air outlet through the first hole.

Description

AEROSOL GENERATING DEVICE

FIELD OF INVENTION

The invention relates to aerosol generating devices. In particular, the invention relates to aerosol generating devices configured to generate an electric current through an aerosol generating substance provided in a consumable.

BACKGROUND TO THE INVENTION

Some aerosol generating devices generate an aerosol by heating an aerosol forming substance comprising tobacco to high temperatures that are below the combustion temperature of tobacco. A heating oven can be used to raise the temperature of the aerosol forming substance to the appropriate temperature. However, it can take tens of seconds for the oven to reach the required temperatures in many devices.

One technique to avoid such prolonged preheating times involves including a conductive material in the aerosol forming substance and using electrodes to generate an electric current directly through the aerosol forming substance. The electrical resistance of the conductive material causes heat to be generated in response to the current, allowing the aerosol generating substance to be heated quickly from within. However, adding conductive substances to the aerosol forming substance in this way can increase the density of the aerosol forming substance, making it difficult for a user to draw air through the substance in use. The aerosol forming substance can also heat unevenly, which negatively impacts the quality of the generated aerosol.

It is an object of the invention to address these issues.

In WO 2021/069525 A1 , a device comprising piercing elements adapted to pierce a consumable to form an electrical connection between the piercing elements and a heater layer in the consumable is disclosed. The consumable disclosed therein can contain perforations to increase airflow through the consumable. In US 2018/084831 A1 , a sachet of aerosol-forming substrate for an electrically heated aerosol-generating device is disclosed. The device comprises hollow piercing elements used to pierce the sealed sachet to form an airflow pathway through the sachet.

SUMMARY OF INVENTION

According to an aspect of the present invention, there is provided an aerosol generating device configured to generate an aerosol for inhalation by a user, comprising: a first air inlet, an air outlet, and an air channel configured to fluidically connect the first air inlet and the air outlet; a first electrode and a second electrode, configured to generate an electric current through a consumable comprising an aerosol generating substance; a cavity positioned in the air channel and in a layer between the first electrode and the second electrode, the cavity configured to receive the consumable; a first protrusion provided on the first electrode, arranged to protrude into the cavity and configured to pierce an external surface of the consumable when the consumable is received within the cavity; wherein the first electrode comprises a first hole provided at the first protrusion and the air channel is configured to fluidically connect the first air inlet to the air outlet through the first hole.

When the consumable is placed in the cavity, the first protrusion can pierce an external surface of the consumable. In this way, the first electrode can make electrical contact with material beyond the external surface of the consumable. This provides a better electrical contact with conductive material inside the consumable to promote a more even current flow by increasing the surface area of the first electrode in contact with the consumable. Consequently, more even heating is promoted throughout the consumable. Additionally, the aerosol forming material may have an uneven density distribution that can cause some parts of the consumable to receive less electrical current in use compared to other parts. The first protrusion can pierce through the surface to allow some less dense regions close to the surface of the consumable to come into direct contact with the first electrode. The first electrode and the second electrode may have an electrical resistance that is lower or substantially lower than would typically be used in a heating plate for a heating oven in other types of aerosol generating devices. In this way, the first and second electrodes can be optimised for providing current to the conductive material in the aerosol forming substance, rather than for resistive heating. This may be more energy efficient and provide faster heating of the aerosol generating substance.

The first hole is provided at the first protrusion to connect the first air inlet to the air outlet. Piercing through the surface of the consumable bypasses some of the dense aerosol generating substance such that the user does not need to draw air through as much of the aerosol generating substance. This improves the airflow through the consumable and makes it easier for the user to inhale the generated aerosol during use. Furthermore, providing the first hole on the first electrode improves airflow through the consumable without the need for providing holes or slots in the consumable itself, which would undesirably degrade the electrical contact between the consumable and electrodes.

The first hole is provided at the first protrusion, which can be embodied in several ways. In one example, the first hole is provided through the first protrusion, for example as a bore or slot. In another example, the first hole is provided adjacent the first protrusion, an arrangement that can be realised by puncturing the first electrode to create a protruding flap. In these cases the first hole is provided with the first protrusion. This enables the first protrusion to be impressed into the consumable to clear a small air channel within the consumable that can communicate with the first hole. This can allow air flowing through the consumable to reach the first hole more easily.

The first electrode may comprise a substantially flat panel or surface on which the first protrusion is provided. The first protrusion can have any suitable shape, such as a curved shape produced by perforating the first electrode with a circular hole punch from an outer side of the first electrode that faces away from the cavity in use. In another example, the first protrusion can comprise one, two, or more triangular elements, each having an edge or vertex that protrudes into the cavity. The first hole may be provided as a bore, slot or any other suitable type of aperture at or through the first protrusion. The first hole may also extend through other parts of the first electrode to further improve airflow through the first electrode and improve the ease with which a user can draw air from the cavity.

The first and second electrodes may be spaced apart by any suitable distance, such as 2, 3, 4 or 5 mm, or more, to provide the cavity between the first and second electrodes.

Preferably, the first hole is positioned relative to the first air inlet and the air outlet to generate a change of direction in airflow to couple air from the first air inlet to the air outlet when air is drawn through the air channel during use. In this way, the first hole can be used to reduce a path length of airflow that passes through the consumable. In one example, air may enter the cavity from the first air inlet at a peripheral portion of the cavity and the air may exit the cavity using the first hole. Compared to an arrangement wherein air exits from an opposite peripheral portion of the cavity, the path length of the airflow through the consumable can be reduced. This improves the ease with which a user can draw air through the consumable.

Furthermore, it has been found that reducing the path length of vapour flow through the consumable increases the volume of vapour that can be extracted by a user in use. This may occur because vapour generated near the air inlet can condense while travelling towards the air outlet through the consumable, thereby preventing extraction of the vapour. The first hole enables vapour generated nearer the first air inlet to reach the air outlet by travelling less distance through the consumable, reducing the likelihood of the generated vapour condensing before extraction. In one example, providing the first hole can reduce the path length of vapour through the consumable compared to a maximum of 18 mm in a known arrangement having no holes and air inlets and outlets positioned at opposing ends of an 18 mm consumable. The maximum path length can be reduced to about 9 mm if the first hole is placed halfway along the cavity. In another example wherein a plurality of holes is provided, the holes distributed across the first electrode, the maximum path length through the consumable can be reduced to about 2 mm.

The first hole, or equivalently the first protrusion, may be positioned relative to the first air inlet and the air outlet to generate a non-linear airflow through the consumable. In other embodiments, any air inlets and the air outlet can have any other suitable arrangements relative to the first hole.

Preferably, the first hole is positioned to generate a change of direction in airflow of about 90 degrees. It has been found that the increase in vapour extraction associated with reducing the path length of vapour through the consumable is particularly prominent for a change of direction in airflow of about 90 degrees.

Preferably, the second electrode comprises at least a second protrusion arranged to protrude into the cavity. A second hole may be provided at the second protrusion to improve airflow through the consumable, in some arrangements. Thus, second electrode may be configured in the same manner as the first electrode. In other arrangements, airflow may not be provided at the second electrode, in which case the second protrusion, or any other protrusions provided on the second electrode, may be provided without a corresponding hole.

Preferably, the second protrusion is configured to pierce an external surface of the consumable when the consumable is received within the cavity. In this way, electrical contact between the consumable and the second electrode can be improved. Providing protrusions on the first and second electrodes can enable the consumable to be provided with a non-conductive wrapper, such as paper, because the first and second electrodes can pierce through the paper to make electrical connection with the conducting aerosol generating substance. Providing a wrapping reduces the debris from the consumable entering the aerosol generating device. Paper wrappings may be convenient and cheap to produce. Alternatively or in addition, a conductive wrapping such as carbon paper or aluminium can be used. However, the consumable can also be provided without a wrapping. Preferably, the first electrode comprises a plurality of protrusions and a plurality of holes provided respectively at the plurality of protrusions, and the air channel is configured to fluidically connect the first air inlet to the air outlet using the plurality of holes. In this way, the airflow through the consumable and the electrical connection with the consumable can be improved across a greater proportion of the consumable.

If a plurality of protrusions with corresponding holes are provided on the first (or second) electrode, these may be clustered in a central region of the first (or second) electrode. In other words, the plurality of protrusions may be provided preferentially towards the centre of the first electrode in comparison to peripheral regions. Alternatively, the plurality of protrusions may be spaced substantially evenly across the first (and/or second) electrode.

Equally, the second electrode can comprise a second plurality of protrusions, and, optionally, a second plurality of holes provided respectively at the second plurality of protrusions.

Preferably, the aerosol generating device further comprises a second air inlet, wherein the air channel is configured to fluidically connect the second air inlet to the air outlet using the first hole. In this way, the airflow through the consumable can be improved.

Preferably, the first air inlet and the second air inlet are positioned at different respective ends or regions of the cavity. The first and second air inlets can be positioned at opposite ends or peripheral regions of the cavity. In this way, the consumable can be exposed to airflow more evenly, helping to ensure that all of the generated aerosol is carried out of the cavity. The first protrusion, or protrusions, may be positioned in a central region of the first electrode, so that the first hole can reduce the path length of air flowing through the consumable for air entering the cavity from the first air inlet and the second air inlet in equal amounts. In some embodiments, the first electrode and the second electrode have different shapes. The shapes may be chosen to implement a desired current flow path through the consumable. For example, the first or second electrode can comprise a plurality of separated electrical contact points held at different electric potentials. The contact points can be configured as separate electrode plates, wherein adjacent plates are held at electric potentials alternating in magnitude or polarity. The first electrode and the second electrode may have any suitable shapes.

Preferably, the second electrode is arranged or configured to inhibit airflow through the second electrode. In one example, the second electrode does not comprise a hole or gap configured to couple air from the first air inlet to the air outlet. Such a hole or gap may not be necessary in certain arrangements. In another example, the first air inlet and the air outlet may be positioned with respect to the second electrode so that air bypasses the second electrode when passing through the air channel.

The second electrode can comprise a plurality of separated sections that are positioned adjacent to one another. The plurality of separated sections may be configured to operate at different electric potentials when generating the electric current through the consumable. In this way, the first electrode and the second electrode can generate a substantially non-linear electric current flow path through the consumable, which may promote more even heating of the aerosol forming substance. The second electrode may comprise any suitable number of separated sections, such as 2 to 6. Each of the separated sections may operate at an electric potential during use with the same magnitude but alternating charge. In other words, the separated sections may have a mixture of positive and negative electric potentials in use. The positive and negative sections may be arranged in an alternating manner, which may generate a substantially serpentine current flow path through the consumable. The first electrode may also be provided as a plurality of separated sections in the same manner.

Preferably, the aerosol generating device further comprises a hinge connecting the first and second electrodes, wherein the hinge is configured to enable the user to move one of the first or second electrodes to insert the consumable into the cavity. In this way, the user can insert or remove the consumable from the cavity more easily. In one example, one of the first or second electrodes may be positioned on a door provided on a housing of the aerosol generating device, wherein the hinge enables opening and closing of the door. Any other suitable movement mechanism may be implemented alternatively, for example a mechanism using sliding action.

Preferably, the first and second electrodes are configured to clamp the consumable when the consumable is received within the cavity and the hinge is in a closed position. In this way, the consumable can be compressed to a density more optimal for current flow through the consumable. The hinge may be biased to a closed position to provide clamping of the consumable. Alternatively, a latch or similar mechanism may be provided to hold the first and second electrodes in a contracted position. Any other suitable mechanism of providing clamping may be implemented.

In some embodiments, the first electrode comprises a second hole and/or a slot configured to enable airflow through the first electrode. In this way, the airflow through the first electrode can be further improved to reduce the difficulty for the user in drawing air through the cavity. The second hole or slot may be provided on a base plate of the first electrode and may be separate from or continuous with the first hole. A plurality of additional holes or slots may be provided on the first electrode. Similarly, the second electrode can comprise additional holes or slots through a base panel.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are now described, by way of example, with reference to the drawings, in which:

Figure 1 shows a schematic diagram of an aerosol generating device in an embodiment of the invention; Figure 2 shows a perspective view of first and second electrodes in an embodiment of the invention;

Figure 3 shows a cross sectional schematic diagram of first and second electrodes in use in an embodiment of the invention;

Figure 4 shows a perspective view of an electrode in an embodiment of the invention;

Figure 5 shows a cross sectional schematic diagram of first and second electrodes in use in an embodiment of the invention;

Figure 6 shows a schematic perspective view of an electrode and a consumable in an embodiment of the invention;

Figure 7 shows a cross sectional schematic diagram of first and second electrodes in use in an embodiment of the invention; and

Figure 8 shows a schematic perspective view of first and second electrodes and a consumable in an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic diagram of an aerosol generating device according to an embodiment of the invention. An aerosol generating device 100 is provided and comprises a housing 102 for containing and protecting internal components of the aerosol generating device 100, a controller 104 configured to control the operation of the electronic components of the aerosol generating device 100, and a battery 106 comprising first and second terminals connected by wires (not shown) to a first electrode 108 and a second electrode 110, respectively. A cavity 112 is provided in a layer between the first electrode 108 and the second electrode 110 for receiving a consumable 10 comprising an electrically conductive aerosol generating substance. The first electrode 108 comprises a plurality of protrusions 114 that project into the cavity 112 for piercing a surface of the consumable 10. One of a plurality of holes 116 is provided at each of the protrusions 114, and specifically in this embodiment the holes extend through the respective protrusions 114. A first air inlet 118 and a second air inlet 120 are provided as openings in the housing 102 to fluidically connect the cavity 112 to the external atmosphere. An air outlet 122 is provided on a mouthpiece 124 and is fluidically connected to the first and second air inlets 118, 120 by the cavity 112 and the holes 116. Thus, the cavity 112 and the holes 116 provide an air channel (A) between the first and second air inlets 118, 120 and the air outlet 122. A button 126 is provided on the housing 102 for enabling a user to control operations of the aerosol generating device 100.

The housing 102 can comprise any suitable material, such as plastic or metal. The controller 104 may comprise a memory and a processor for storing and executing instructions, respectively. The controller 104 is connected electrically to the battery 106 and can enable or prevent current flow from the battery 106 to the first electrode 108 and the second electrode 110 based on a user input from the button 126, to which the controller 104 is also connected. In other embodiments, the button 126 can be provided as any other suitable input mechanism, such as an airflow or fingerprint sensor. Other components may be provided in the aerosol generating device 100, such as a temperature sensor for measuring the temperature of the cavity 112. A hinged door or any other suitable mechanism (not shown) may be provided to enable the insertion and removal of the consumable 10 from the cavity 112 within the aerosol generating device 100. One of the first and second electrodes 108, 110 may be attached to the hinged door or other suitable mechanism to enable the removal or insertion of the consumable 10 from the cavity 112. The consumable 10 comprises an aerosol forming substance, which can include tobacco or other suitable aerosol generating materials. The aerosol forming substance comprises an electrically conductive material, such as charcoal, to allow the consumable 10 to conduct electricity.

Figure 2 shows a perspective view of the first electrode 108 and the second electrode 110 in the embodiment of Figure 1. The first electrode 108 is configured to receive (or provide) electrical current from (or to) the second electrode 110 through contact with the consumable 10 provided in the cavity 112. This enables the first electrode 108 and the second electrode 110 to generate a current through the conductive material in the consumable 10, which generates heat in response to the current due to its electrical resistance.

The first electrode 108 and the second electrode 110 each comprise a substantially planar plate with a polygonal shape as shown in Figure 2. The first electrode 108 and the second electrode 110 can have any other suitable shape, such as a rectangular or circular shape. The consumable 10 is shaped as a substantially flat cuboidal block with a length and width equal to or less than the first and second electrodes 108, 110. The consumable 10 may also have a variety of shapes that may correspond to the shapes of the first and second electrodes 108, 110. The first and second electrodes 108, 110 can comprise any suitable materials, such as metals or metal alloys, or other conducting materials. The first and second electrodes 108, 110 may each comprise one or more fixing holes 128 for fixing the first and second electrodes 108, 110 to other components within the aerosol generating device 100.

As shown in Figure 1 , the first and second electrodes 108, 110 are positioned substantially parallel to one another, spaced apart to form the cavity 112 therebetween. The first and second electrodes 108, 110 may be spaced apart by 1 to 5 mm, or by any other suitable spacing. In this embodiment, the first air inlet 118 is provided towards one edge or side of the first and second electrodes 108, 110, while the second air inlet 120 is provided towards an opposite side or edge. Thus, air flows through the cavity 112 from the first and second air inlets 118, 120 substantially parallel to the first and second electrodes 108, 110, as shown by the arrow A in Figure 1 , before reaching the holes 116. Upon reaching the holes 116, the airflow turns by 90 degrees to pass through the holes 116 towards the air inlet 122, which is positioned radially inwardly of the first and second air outlets 118, 120. In other arrangements, the airflow may follow other non-linear paths through the aerosol generating device 100.

In other embodiments, other arrangements could be implemented. In one example, one or both of the first and second air inlets 118, 120 could be arranged to provide air to holes in the second electrode 110. In this case, some or all of the air flowing through the cavity 112 would follow a path through the cavity 112 substantially perpendicular to the first and second electrodes 108, 110.

The protrusions 114 are configured to pierce an external surface of the consumable 10 to enable improved electrical contact between the first electrode 108 and the conductive material inside the consumable 10. In the embodiment of Figure 1 , the protrusions 114 of the first electrode 108 can be formed from punching circular holes 116 through the first electrode 108, as shown more clearly in Figure 2. The protrusions 114 therefore have a curved shape corresponding to the circular holes 116. In other embodiments, such as embodiments described further below, the protrusions 114 can have any other suitable shape. For example, triangular or rectangular holes can be punched through the first electrode 108, in which case the protrusions 114 and holes 116 may have a non-circular cross-sectional shape. The protrusions 114 can be provided with a sharp edge to enable the surface or a wrapper of the consumable 10 to be pierced more effectively.

The holes 116 are clustered in a hexagonal arrangement in a central region of the first electrode 108. This positioning of the holes 116 may be chosen to align with the air outlet 122, as shown in Figure 1. Providing the holes 116 away from the edges of the first electrode 108 may also improve the airflow through some peripheral parts of the cavity 112. The protrusions 114 and corresponding holes 116 can have any other suitable spacing or distribution on the first electrode 108.

Figure 3 shows a cross sectional schematic view of the first and second electrodes 108, 110 during operation of the aerosol generating device 100. The consumable 10 is provided in the cavity 112 while the controller 104 allows current to flow from the battery 106. In this example, the battery 106 provides current to the second electrode 110 using a wire connecting the first terminal of the battery to the second electrode 110. The first electrode 108 is connected to the second terminal of the battery 106 by a different wire. Alternatively, the first terminal of the battery 106 can be configured to provide current to the first electrode 108, in which case current would flow in an opposite direction.

As shown by the arrows C, current flows through a conductive material in the consumable 10 from the second electrode 110 to the first electrode 108. The conductive material has a sufficiently low electrical resistance and sufficiently high density in the consumable 10 to enable current to flow through the consumable 10. At the same time, the conductive material has a sufficiently high resistance and a sufficiently low density in the consumable 10 to provide the consumable 10 with a high enough electrical resistance to generate heat efficiently.

An example use of the aerosol generating device 100 by a user will now be described with reference to Figures 1 to 3.

Once the consumable 10 is provided in the cavity 112, the user can initiate aerosol generation by pressing the button 126. In response, the controller 104 enables current to flow from the battery 106 through the consumable 10. The resistance of the electrically conductive material in the consumable 10 generates heat in response to the current. The conductive material is present throughout the consumable 10, thus the whole consumable heats up quickly from within. This enables the consumable 10 to reach aerosol generating temperatures within a few seconds. The controller 104 may be configured to regulate the supply of power from the battery 106 to the first and/or second electrodes 108, 110 to maintain the cavity 112 at a particular temperature. The controller 104 may be configured to maintain the temperature of the cavity 112 below the combustion temperature of tobacco.

Heat generated by the conductive material in the consumable causes the aerosol forming substance in the consumable 10 to form an aerosol in the cavity 112. To a lesser extent, the first and second electrodes 108, 110 may provide some heating of the consumable 10 due to resistive heating caused by their electrical resistances. However, the first and second electrodes 108, 110 have electrical resistances or any other properties optimised for delivery of current to the consumable 10 rather than for resistive heating. In one example, the first and second electrodes 108, 110 may have lower electrical resistances than is typically used for heating plates in other devices.

The user can inhale the generated aerosol through the air outlet 122 on the mouthpiece 124. This draws air through the first and second air inlets 118, 120 and the cavity 112 through the holes 116. The aerosol generated in the cavity 112 is carried through the holes 116 to the air outlet 122. The high density of the material in the consumable 10 means that, in general, it can be difficult for the user to draw air through the consumable 10. However, the positioning of the first and second air inlets 118, 120 and the holes 116 allows air reaching the cavity from the air inlets 118, 120 to reach the air outlet 122 without having to travel through the full length of the consumable 10. Reducing the path length of air passing through the consumable 10 in this way makes it easier for the user to draw air through the air outlet 122. Having two air inlets positioned at opposite sides of the cavity 112 nevertheless enables the full length of the consumable 10 to receive airflow so that all or most of the generated aerosol can be carried to the user. Additionally, as best seen from Figure 3, the protrusions 114 protrude into the cavity 112 so that air flowing through the consumable 10 must travel less distance from one of the first or second air inlets 118, 120 before reaching the holes 116. This further reduces the minimum path length that air must travel through the consumable 10 to reach the air outlet 122, making it easier for the user to inhale the generated aerosol.

The protrusions 114 project from the surface of the first electrode 108 towards the second electrode 110, i.e., into the cavity 112. The protrusions 114 pierce a surface (S) of the consumable 10, as shown in Figure s, enabling the first electrode 108 to contact material below the surface S of the consumable 10 directly. The protrusions 114 may also enable or provide compression on the consumable 10. The piercing and/or compression effects of the protrusions 114 can improve the electrical contact between the first electrode 108 and the consumable 10 to promote more homogenous current flow. Consequently, the consumable 10 receives more homogeneous heating, which provides a betterquality aerosol.

As described previously, the first and second electrodes 108, 110 can have any suitable shape. In one example, the second electrode can comprise a plurality of separated sections provided adjacent to one another. Figure 4 shows a perspective view of such an embodiment, in which a second electrode 210 is provided as a plurality of elongated rectangular electrode plates 211. The second electrode 210 can be used in the aerosol generating device 100 of Figures 1 to 3 in substantially the same way as the second electrode 110.

Each of the electrode plates 211 has two respective fixing holes 128 at either end for securing the plates within the aerosol generating device 100. In other embodiments, the electrode plates 211 can have one fixing hole 128 or can be fixed in place by other means. In use, the electrode plates 211 are provided spaced apart from one another, approximately as shown in Figure 4. The first electrode 108 can be provided substantially parallel to the second electrode 210, spaced apart in a perpendicular direction to form the cavity 112 as described with respect to Figures 1 to 3.

Figure 5 shows a schematic cross sectional view of the first electrode 108 and the second electrode 210 in use. The individual electric potentials of the electrode plates 211 and/or the first electrode 108 can be chosen or manipulated to generate different current flow paths of current through the consumable 10. In this example, the electrode plates 211 have electric potentials that alternate between negative and positive values between adjacent electrode plates 211. As illustrated by the arrow C, this enables the current flowing through the consumable 10 to take a different path through the consumable 10 compared to the embodiments of Figures 1 to 3. The current may follow a substantially serpentine path through the consumable 10 in the example of Figure 5. The electric potential of the first electrode 108 may be held at a positive value, negative value, or may alternate depending on the desired flow of current through the consumable 10. Manipulating the current flow path in this way may promote more even heating of the consumable 10. Figure 6 shows a perspective view of an alternative first electrode 308 having triangular protrusions 314 and elongate slots 316 provided through the protrusions 314. An alternative consumable 20 is also shown, which comprises an aerosol forming substance 22 contained by a wrapper 24, which may comprise paper and/or aluminium in one or more layers. The first electrode 308 and the consumable 20 can be used in the aerosol generating device 100 in the same way as described previously with respect to Figures 1 to 5. The consumable 10, which does not have a wrapper 24, may also be used with the first electrode 308. The first electrode 308 may be used alongside any suitable type of second electrode, such as the second electrode 110 or the second electrode 210 as described previously, or alongside a second electrode 310 having the same shape as the first electrode 308. Such an embodiment is described below with respect to Figure 7.

The first and second air inlets 118, 120 may be provided at any of the peripheral edges of the first electrode 308, as described previously. Alternatively, one or more air inlets can be provided at other positions relative to the first electrode 308. One alternative example is described further below with reference to Figure 7.

In the embodiment of Figure 6, the holes through the first electrode 308 are formed as elongate slots 316. Each of the elongate slots 316 extend through several protrusions 314, which in this example are arranged in regular rows on the first electrode 308. The elongate slots 316 can extend across the full width of the first electrode 308, as shown by Figure 6. Alternatively, the elongate slots 316 can extend through only a proportion of the first electrode 308. The elongate slots 316 extend through other parts of the first electrode 308 in addition to the protrusions 314 to promote greater airflow through the first electrode 308. The cross sectional surface area of the elongate slots 316 is larger than the cross sectional area of one of the holes 116. This may also enable improved aerosol flow through the consumable 20 or the consumable 10 during use. The protrusions 314 are provided as a triangular structure bisected by one of the elongate slots 316, thereby forming two substantially right-angled triangles on either side of a respective slot with an edge protruding into the cavity 112. The shape of the triangular protrusions 314 may provide enhanced compression of the consumable 20 when received within the cavity 112. The triangular shape of the protrusions 314 may also penetrate further or more reliably into the aerosol forming substance compared to the protrusions 114, further improving the contact between first electrode 308 and the consumable 20. The protrusions 314 may each have a protruding edge that is sufficiently sharp to pierce the wrapper 24.

During use, a user may inhale generated aerosol through the air outlet 122 on the mouthpiece 124 to draw air from the cavity 112 through the elongate slots 316. This generates an airflow (B) from the slots 316 towards the air outlet 122, shown schematically in Figure 6 by the dashed ellipse and the airflow B.

Figure 7 shows a cross sectional schematic diagram of an embodiment using the first electrode 308 and a second electrode 310 configured in the same manner as the first electrode 308. The second electrode 310 has triangular protrusions 330 and elongate slots 332 bisecting the protrusions 330. The second electrode 310 is spaced from the first electrode 308 by a suitable distance, such as 1-5 mm, to provide the cavity 112 between the first and second electrodes 308, 310, with the protrusions 330 facing the first electrode 308.

Having protrusions on both electrodes enables the consumable 20 to be provided with a non-conductive wrapper 24, such as paper, because both electrodes can pierce through the wrapper to make contact with the aerosol forming substance 22 underneath.

In the example of Figure 7, an air inlet 318 is provided in fluidic connection with the elongate slots 332, as shown schematically by the dashed ellipse and the exemplary airflow D through the cavity 112. The air outlet 122 is provided in fluidic connection with the elongate slots 316. Thus, the airflow D follows a path substantially perpendicular to the first and second electrodes 308, 310.

In this example, the second electrode 310 comprises elongate slots 332, however in other embodiments the second electrode 310 may not comprise any holes or slots 332 through the protrusions 330. In this case, one or more air inlets may be provided at a periphery of the cavity 112, rather than adjacent the elongate slots 316, as described previously.

Figure 8 shows a perspective view of an alternative embodiment in which a first electrode 408 is provided opposite a second electrode 410 for use in the aerosol generating device 100 as described previously. The first and second electrodes 408, 410 are connected by a hinge 401 at one end to enable insertion and removal of the consumable 10 (or the consumable 20) into or from the cavity 112. A latch or other mechanism may be provided to lock the first and second electrodes into a closed position to maintain the consumable 10 securely within the cavity 112. The first and seconds electrodes may be configured to compress the consumable 10 when the latch is engaged. The hinge may also be biased to a closed position in addition or alternatively to the latch or other mechanism. A similar hinge may be provided for the embodiments described with respect to Figures 1 to 7. In this example, the first electrode 408 and the second electrode 410 each comprise a plurality of protrusions 414 that may be formed by punching a plurality of triangular holes 416 through each of the first and second electrodes 408, 410. The protrusions 414 are each configured as a triangular flap with a vertex protruding into the cavity 112, each protrusion 414 provided adjacent a corresponding hole 416. In this way, each hole 416 is provided at the location of a corresponding protrusion 414. The use of a vertex may provide a more effective piercing means compared to sharp edge. The protrusions 414 may create a small air channel in the consumable 10 when the consumable 10 is pressed against the first electrode 408 and the second electrode 410 to aid airflow through the consumable 10.

The protrusions 414 are arranged in regular rows across a substantially full surface area of each of the first and second electrodes 408, 410 to promote good electrical contact with a substantially full length and width of the consumable 10. Previous embodiments described with respect to Figures 1 to 7 may be configured similarly.

Claims

1. An aerosol generating device configured to generate an aerosol for inhalation by a user, comprising: a first air inlet, an air outlet, and an air channel configured to fluidically connect the first air inlet and the air outlet; a first electrode and a second electrode, configured to generate an electric current through a consumable comprising an aerosol generating substance; a cavity positioned in the air channel and in a layer between the first electrode and the second electrode, the cavity configured to receive the consumable; a first protrusion provided on the first electrode, arranged to protrude into the cavity and configured to pierce an external surface of the consumable when the consumable is received within the cavity; wherein the first electrode comprises a first hole provided at the first protrusion and the air channel is configured to fluidically connect the first air inlet to the air outlet through the first hole.

2. The aerosol generating device of claim 1 , wherein the first hole is positioned relative to the first air inlet and the air outlet to generate a change of direction in airflow to couple air from the first air inlet to the air outlet when air is drawn through the air channel during use.

3. The aerosol generating device of claim 2, wherein the first hole is positioned to generate a change of direction in airflow of about 90 degrees.

4. The aerosol generating device of any of the preceding claims, wherein the second electrode comprises at least a second protrusion arranged to protrude into the cavity.

5. The aerosol generating device of claim 4, wherein the second protrusion is configured to pierce an external surface of the consumable when the consumable is received within the cavity.

6. The aerosol generating device of any of the preceding claims, wherein the first electrode comprises a plurality of protrusions and a plurality of holes provided respectively at the plurality of protrusions, and wherein the air channel is configured to fluidically connect the first air inlet to the air outlet using the plurality of holes.

7. The aerosol generating device of any of the preceding claims, further comprising a second air inlet, wherein the air channel is configured to fluidically connect the second air inlet to the air outlet using the first hole.

8. The aerosol generating device of claim 7, wherein the first air inlet and the second air inlet are positioned at different respective ends of the cavity.

9. The aerosol generating device of any of the preceding claims, wherein the first electrode and the second electrode have different shapes.

10. The aerosol generating device of claim 9, wherein the second electrode is arranged or configured to inhibit airflow through the second electrode.

11. The aerosol generating device of claim 9 or claim 10, wherein the second electrode comprises a plurality of separated sections that are adjacent to one another.

12. The aerosol generating device of claim 11 , wherein the plurality of separated sections are configured to operate at different electric potentials when generating the electric current through the consumable.

13. The aerosol generating device of any of the preceding claims, further comprising a hinge connecting the first and second electrodes, wherein the hinge is configured to enable the user to move one of the first or second electrodes to insert the consumable into the cavity.

14. The aerosol generating device of claim 13, wherein the first and second electrodes are configured to clamp the consumable when the consumable is received within the cavity and the hinge is in a closed position.

15. The aerosol generating device of any of the preceding claims, wherein the first electrode comprises a second hole and/or a slot configured to enable airflow through the first electrode.