WO2024126562A1

WO2024126562A1 - Cartridge comprising a heat conducting layer and associated aerosol generating system

Info

Publication number: WO2024126562A1
Application number: PCT/EP2023/085537
Authority: WO
Inventors: Alec WRIGHT
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2022-12-15
Filing date: 2023-12-13
Publication date: 2024-06-20
Anticipated expiration: 2025-06-15

Abstract

The present invention concerns a cartridge (12) configured to operate with an aerosol generating device comprising a heating surface; the cartridge (12) comprising: - a reservoir (51); - a wick (60) comprising an absorbing surface (65) arranged in fluid communication with the reservoir (51) and a vaporizing surface (67); - a heat conducting layer (62) comprising a first surface (71) arranged adjacent to the vaporizing surface (67) of the wick (60) and a second surface (72) opposite to the first surface (71) and forming a part of an external surface (40) of the cartridge (12), the second surface (72) configured to be in contact with the heating surface when the cartridge (12) is operating with the aerosol generating device; wherein the heat conducting layer (62) comprises a carbon based material.

Description

Cartridge comprising a heat conducting layer and associated aerosol generating system

FIELD OF THE INVENTION

The present invention concerns a cartridge and an aerosol generating system associated to such a cartridge.

BACKGROUND OF THE INVENTION

Consumable cartridges, also known as pods, are used in aerosol generating devices such as electronic cigarettes and vaping devices to provide a vaporizable material that is heated to generate an aerosol or vapour for inhalation by a user. In case of a liquid vaporizable material, the consumable cartridge includes generally a wick that ensures liquid transmission from a reservoir to a heating element where it is vaporized and mixed with an airflow coming from the exterior of the cartridge.

Some known cartridges include also the heating element used to vaporize the vaporizable material. In such a case, the device is provided with electrical connection means which connect electrically the cartridge to the device and supply the heating element with electrical power. However, since this type of cartridges includes multiples plastic and metallic components, their recycling process can be complicated. Additionally, they can produce a negative environmental impact.

In order to solve this issue, some aerosol generating devices include a heating element which is designed to heat the wick of the cartridge by heat transfer. However, heat transfer is not always optimal that causes heat losses and reduces the energy efficiency of the whole system. This can have a strong impact on the quality of aerosol generation and conduct to a poor user experience.

SUMMARY OF THE INVENTION

An aim of the present invention is to improve the user experience by optimizing heat transfer between a cartridge and a device, without creating a negative environmental impact. For this purpose, the invention concerns a cartridge configured to operate with an aerosol generating device comprising a heating surface; the cartridge comprising:

- a reservoir configured to store a liquid vaporizable material;

- a wick comprising an absorbing surface arranged in fluid communication with the reservoir and a vaporizing surface;

- a heat conducting layer comprising a first surface arranged adjacent to the vaporizing surface of the wick and a second surface opposite to the first surface and forming a part of an external surface of the cartridge, the second surface configured to be in contact with the heating surface of the aerosol generating device when the cartridge is operating with the aerosol generating device to generate aerosol; wherein the heat conducting layer comprises a carbon based material.

The layer structure of the heat conducting layer allows an efficient heat transfer from the second surface to the first surface in comparison with any other structure having a complex shape. Particularly, in this case, the first and the second surfaces present substantially the same area and shape. The thickness of the heat conducting layer can be sufficiently small to ensure efficient and fast heat transfer from the second surface to the first surface.

Additionally, the first surface of the heat conducting layer can be firmly attached to the vaporizing surface to avoid or minimize air gaps between these elements. Thus, the heat transfer to the wick can be further improved.

The heat conducting layer can form a unique piece made from one or several materials as it is explained below. Thus, it can be cheap and easy to manufacture and can be easily mounted in the cartridge. For example, the heat conducting layer can be formed using a cutting process of a pre-fabricated sheet comprising a carbon based material.

Additionally, any contact of the heat conducing layer with the airflow passing through the cartridge can be avoided. Particularly, the heat conducting layer is intended to heat directly the wick and only undirectly the airflow and/or the vaporizable material (through the wick). Advantageously, the wick presents a porous element ensuring a substantially constant flow rate of the liquid vaporizable material through it. This flow rate is for example substantially independent from the temperature of the fluid vaporizable material.

The heat conducting layer comprising a carbon based material can ensure an optimal heat transfer from the heating surface of the aerosol generating device to the wick of the cartridge.

In some embodiments, the heat conducting layer is made from the carbon based material. In some other embodiments, the heat conducting layer contains the carbon based material together with any other material ensuring at least some physical properties of the conductive layer. Such a material can be a binder maintaining together carbon based particles or forming a structure of the conductive layer. In a general case, the mass fraction of the carbon based material in the heat conducting layer can be at least 50%, advantageously at least 70% and preferably 90%.

The carbon based material can correspond to any known material such as graphite or graphene, or comprise a mixture of these materials. The carbon based material can be in form of carbon particles bonded together.

Advantageously, the heat conducting layer presents a pyrolytic graphite sheet (PGS). This material has advantage to be very thin, synthetically made, present a high thermal conductivity and be made from a highly oriented graphite polymer film. Additionally, this material is flexible. It can for example present a thermal conductivity comprised between 700 and 2000 W/(mK). It can also present a heat resistance (for example about 400°C) suitable for supporting heating by the aerosol generating device.

The thickness of the heat conducting layer can be comprised between 0,01 mm and 2 mm, advantageously between 0,05 mm and 0,5 mm.

The heat conducting layer can be flexible. Thus, the contact and consequently the heat transfer between the heat conducting layer and the wick and/or the heating surface can further be improved.

In some embodiments, the heating conducting layer is liquid impermeable and advantageously gas impermeable. To achieve the liquid and advantageously gas impermeability, according to some embodiments, the heat conducting layer can comprise a coating preventing leakages from the cartridge.. This is particularly advantageous when the carbon based material is porous. According to some other embodiments, the liquid and advantageously gas impermeability can be achieved using any other appropriate material incorporated into the carbon based material.

According to some embodiments, the heat conducting layer comprises graphite or graphene.

These materials present particularly advantageous heat transferring properties. Additionally, these materials present a high thermal conductivity in the plane to ensure efficient heat distribution to the vaporizing surface of the wick. Thus, heat losses between the wick and the heating element can be minimized. Additionally, these materials can be easily processed to form a heat conducting layer of a desired thickness and shape.

According to some embodiments, the heat conducting layer extends according to the whole area of the vaporizing surface of the wick. Here, the “area of the vaporizing surface” is understood as the area of a zone formed by an orthogonal projection of the vaporizing surface on a plane extending parallel to the wick.

Thanks to these features, heat transfer can be optimized on the whole area of the vaporizing surface of the wick. Thus, heat can be efficiently transferred through the whole wick.

Advantageously, the heating surface of the aerosol generating device presents substantially the same dimensions and shape that the vaporizing surface of the wick. They can match each other when the cartridge is operating with the device. Preferably, the heat conducting layer has also the same shape and dimensions so as to be perfectly interposed between the heating surface of the device and the vaporizing surface of the wick.

According to some embodiments, the first surface of the heat conducting layer comprises an adhesive coating designed to adherer to the vaporizing surface of the wick. The adhesive coating improves the contact and consequently the heat transfer between the vaporizing surface of the wick and the heating surface of the device. Additionally, the adhesive coating prevents liquid and advantageously gas leakage from the wick.

The adhesive coating can comprise silicon, Polyurethane and/or epoxy glue. It could also be thermal sealed or heat staked between the two components.

According to some embodiments, the heat conducting layer is sandwiched between the vaporizing surface of the wick and the heating surface of the aerosol generating device when the cartridge is operating with the aerosol generating device to generate aerosol.

Thus, contact and consequently heat transfer between the heat conducting layer and the heating and vaporizing surfaces can further be improved when the aerosol generating device is operated to generate aerosol. The heating layer can be sandwiched by any appropriate means exerting pressure to abut a cartridge body against a surface of the device comprising the heating surface.

According to some embodiments, the vaporizing surface of the wick is a non-flat surface.

Thanks to these features, the heat conductive material is not in contact with the entire vaporizing surface of the wick and space is formed between the vaporizing surface and the heat conductive material. Aerosol generated by the vaporizing surface of the wick can thus be conducted through this space until the user’s mouth.

According to some embodiments, the vaporizing surface forms at least one groove forming an airflow channel.

The airflow channel can conduct an airflow from the outside of the cartridge along the vaporizing surface to be mixed with the vaporized liquid and form aerosol.

In some embodiments, the vaporizing surface can comprise a plurality of grooves extending from its periphery to the center. Thus, a plurality of airflow channels can be formed on the vaporizing surface. The shape and the cross-sectional area of each groove can be chosen to optimize airflow along the vaporizable surface. According to some embodiments, the vaporizing surface of the wick is arranged in fluid communication with an airflow path conducting the aerosol formed by the vaporizing surface to the outside of the cartridge.

The airflow path can extend along a cartridge axis through the wick and the reservoir storing the liquid vaporizable material. The airflow path can conduct aerosol formed by the vaporizing surface of the wick to the outside of the cartridge, i.e. until the user’s mouth. When the vaporizing surface is provided with at least one airflow channel, the airflow path extends this channel until the outside of the device. In case of a plurality of airflow channels, these channels can be merged for example at the center of the vaporizing surface to form a unique airflow path.

According to some embodiments, the wick defines a central hole delimiting partially the airflow path.

Advantageously, the central hole of the wick forms one of the ends of the airflow path.

According to some embodiments, the vaporizing surface of the wick is substantially perpendicular to its absorbing surface.

According to these features, the absorbing surface can form a lateral wall of the wick and the vaporizing surface can form a bottom wall of the wick. In this case, the liquid vaporizable material is absorbed by the lateral wall and vaporized by heat issued from the bottom wall of the wick.

According to another embodiment, the absorbing surface faces at least partially the vaporizing surface.

According to some embodiments, the wick is made of ceramics.

The ceramics is particularly advantageous since it presents a high thermal conductivity. Additionally, a porous structure of the wick can easily be formed using ceramics. The invention also concerns an aerosol generating system, comprising:

- a cartridge as defined above; and

- an aerosol generating device configured to operate with said cartridge.

According to some embodiments, the aerosol generating device comprises a heater forming a heating surface designed to be in contact with the second surface of the heat conducting layer of the cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be better understood upon reading the following description, which is given by way of non-limiting example and which is made with reference to the appended drawings, in which:

- Figure 1 is a schematic view of an aerosol generating system according to the invention, the aerosol generating system comprising an aerosol generating device and a cartridge; and

- Figure 2 is detailed view of the cartridge of Figure 1 .

DETAILED DESCRIPTION OF THE INVENTION

Before describing the invention, it is to be understood that it is not limited to the details of construction set forth in the following description. It will be apparent to those skilled in the art having the benefit of the present disclosure that the invention is capable of other embodiments and of being practiced or being carried out in various ways.

As used herein, the term “aerosol generating device” or “device” may include a vaping device to deliver an aerosol to a user, including an aerosol for vaping, by means of a heater element explained in further detail below. The device may be designed and configured to be hand held by a user, i.e. held and used within one hand of the user. The device may be adapted to generate a variable amount of aerosol, e.g. by activating the heater element for a variable amount of time (as opposed to a metered dose of aerosol), which can be controlled by a trigger. The trigger may be user activated, such as by a manual actuator located on an outer surface of the device (button or switch) and/or by means of an airflow or inhalation sensor arranged in the airflow path of the device. The inhalation sensor may be sensitive to the velocity of an airflow passing across the sensor during an inhalation by a user as well as the duration of inhalation to enable a variable amount of vapour to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.). The device may include a temperature regulation control to adjust the temperature of the heater and/or of the heated aerosol generating substance (aerosol precursor) to a specified target temperature and thereafter to maintain the temperature at the target temperature that enables efficient generation of aerosol.

As used herein, the term “aerosol” may include a suspension of vaporizable material as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to/include a vapour. Aerosol may include one or more components of the vaporizable material.

As used herein, the term “vaporizable material” or “precursor” may refer to a material which may comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

Figure 1 shows an aerosol generating system 10 comprising an aerosol generating device 1 1 and a removable cartridge 12 or pod, configured to operate with the aerosol generating device 1 1 . To operate with the cartridge 12, the aerosol generating device 1 1 defines a contact surface 20 designed to be in contact with the cartridge 12. The contact surface 20 may be provided in a recess or a cavity formed in a device body. Such a recess or cavity is adapted to receive at least partially the cartridge 12 and to fix it in this position. According to other embodiments, any other fixing means can be provided to fix the cartridge 12 with the aerosol generating device 1 1 . For example, in some embodiments, the cartridge 12 can be screwed on the aerosol generating device 1 1 . Advantageously, fixing means can exert pressure to abut at least one of the external surfaces of the cartridge 12 against the contact surface 20 of the aerosol generating device 1 1 . In Figure 1 only a heater 22 of the aerosol generating device 1 1 is shown. In a general case, the aerosol generating device 1 1 may further comprise a battery for powering the heater 22 and a controller for controlling the power delivered to the heater 22. The aerosol generating device 11 may further comprise other internal components performing different functionalities of the device 1 1 known per se. These internal components will not be explained in detail below.

The heater 22 is for example a resistive heater comprising a heating surface 24. As shown in Figure 1 , the heating surface 24 forms at least partially the contact surface 20 of the aerosol generating device 1 1. For example, the heating surface 24 can be arranged at the centre of the contact surface 20. In some embodiments, the heating surface 24 can be continuous and form for example a circular or rectangular shape. In some other embodiments, the heating surface 24 can be discontinuous and form for example two or more separate parts. Each part can have for example circular or rectangular shape. The heating surface 24 is formed from a heat conductive material such as metal (aluminium for example) or ceramics.

In reference to Figure 2, the cartridge 12 comprises a cartridge body 30 extending along a cartridge axis X between a distal end 31 and a proximal end 32. In some embodiments, the cartridge body 30 is formed by an outer shell, made for example from aluminium.

The distal end 31 of the cartridge 12 is designed to be engaged with the aerosol generating device 1 1 as explained above. The distal end 31 further forms a bottom wall of the cartridge body 30. This bottom wall defines an external surface 40 which is designed to be in contact with the contact surface 20 of the device 1 1 as previously explained. The distal end 31 also defines one or several inlet holes 42 for providing airflow from the outside of the cartridge 12. The inlet holes 42 can be drilled or formed on a lateral wall of the cartridge body 30. In one embodiment, these holes 42 may be uncovered when the cartridge 12 is engaged with the aerosol generating device 11 . According to another embodiment, the inlet holes 42 may be covered by walls delimiting for example the cavity or the recess receiving at least partially the cartridge 12. In this case, a gap may be formed between these walls and the lateral wall of the cartridge body 30 or the inlet holes 42 may face air-guiding channels formed within the aerosol generating device 1 1 . The proximal end 32 forms an outlet hole 44 which is intended to deliver aerosol formed in the cartridge 12 to the user. In one embodiment, the proximal end 32 can form itself a mouthpiece designed to be in contact with the user’s mouth. According to another embodiment, the proximal end 32 is designed to be engaged with a mouthpiece provided for example by the aerosol generating device 1 1 .

The cartridge body 30 comprises a reservoir 51 , an airflow path 52 and a wick assembly 53. The reservoir 51 stores a liquid vaporizable material. Inside the cartridge body 30, the reservoir 51 extends substantially between the distal end 31 and the proximal end 32 of this body. At the distal end 31 , the reservoir 51 defines an opening in fluid communication with the wick assembly 53 as it will be explained in further detail below. The airflow path 52 is designed to conduct aerosol formed by the wick assembly 53 until the outlet hole 44. The airflow path 52 can for example be delimited by walls forming the reservoir 51 . In the example of Figure 2, the airflow path 52 corresponds to a central nozzle extending through the central part of the reservoir 51 . The wick assembly 53 is arranged between the inlet holes 42, the opening of the reservoir 51 and the airflow path 52. The wick assembly comprises a wick 60 and a heat conducting layer 62.

The wick 60 presents a porous element configured to conduct the liquid vaporisable material from the reservoir 51 to form aerosol and conduct it unit the airflow path 52. For this purpose, the wick 60 comprises an absorbing surface 65 arranged in fluid communication with the reservoir 51 and a vaporizing surface 67 arranged adjacent to the heat conducting layer 62. Particularly, the absorbing surface 65 is arranged adjacent to the opening of the reservoir 51 .

In the example of Figure 2, the wick 60 has a generally cylindrical shape extending along the cartridge axis X and defining for example a circular cross-section. In this example, a lateral wall of the wick 60 forms the absorbing surface 65 and a bottom wall of the wick 60 forms the vaporizing surface 67. In other embodiments, the absorbing surface 65 can be formed at least partially by a top wall of the wick 60.

The wick 60 defines a centre hole that delimits an end of the airflow path 52. The vaporizing surface 67 of the wick 60 is non-flat and defines a plurality of groves forming a plurality of airflow channels extending from the periphery of the wick 60 to the centre hole. Particularly, these airflow channels are designed to guide through the vaporizing surface 67 airflow from the inlet holes 42 to the airflow path 52. Particularly, each airflow channel opens on one hand to the lateral wall of the wick 60, and on the other hand, to the centre hole. When the vaporizing surface 67 is heated by the heating surface 24, airflow passing through these airflow channels is mixed with vaporized vaporizable material and then, is flowing through the centre hole of the wick 60 to be delivered to the user through the airflow path 52. These airflow channels can have different shapes and/or cross-sectional areas to optimize airflow through the vaporizing surface 67. According to another embodiment, no centre hole is formed in the wick 60. In this case, the vapour formed on the vaporizing surface 67 may achieve the airflow path 52 by flowing outside the wick 60 (for example around the wick 60).

The heat conducting layer 62 forms a part of the external surface 40 of the cartridge body 30 and is arranged on this external surface 40 to be sandwiched between the vaporizing surface 67 of the wick 60 and the heating surface 24. Particularly, the heat conducting layer 62 comprises a first surface 71 arranged adjacent to the vaporizing surface 67 of the wick 60 and a second surface 72 designed to be in a tight contact with the heating surface 24 of the device 11 . The heat conducting layer 62, the vaporizing surface 67 and the heating surface 24 present for example the same shape and dimensions in an orthogonal projection to a plane parallel to the heat conducting layer 62. The heat conducting layer 62 comprises a carbon based material and advantageously, is made of a carbon based material. Such a carbon based material is for example graphite or graphene. The thickness of the heat conducting layer can be comprised between 0,01 mm and 2 mm, advantageously between 0,05 mm and 0,5 mm.

According to a particular example, the heat conducting layer 62 presents a pyrolytic graphite sheet (PGS).

Advantageously, the first surface 71 of the heat conducting layer 62 comprises an adhesive coating designed to adherer to the vaporizing surface 67 of the wick 60. The adhering can be made to avoid clogging of the airflow channels formed on the vaporizing surface 67. Additionally, the adhesive coating can ensure impermeability (gas and liquid) of the heat conducting layer 62.

Claims

1. A cartridge (12) configured to operate with an aerosol generating device (1 1 ) comprising a heating surface (24); the cartridge (12) comprising:

- a reservoir (51 ) configured to store a liquid vaporizable material;

- a wick (60) comprising an absorbing surface (65) arranged in fluid communication with the reservoir (51 ) and a vaporizing surface (67);

- a heat conducting layer (62) comprising a first surface (71 ) arranged adjacent to the vaporizing surface (67) of the wick (60) and a second surface (72) opposite to the first surface (71 ) and forming a part of an external surface (40) of the cartridge (12), the second surface (72) configured to be in contact with the heating surface (24) of the aerosol generating device (1 1 ) when the cartridge (12) is operating with the aerosol generating device (1 1 ) to generate aerosol; wherein the heat conducting layer (62) comprises a carbon based material.

2. The cartridge (12) according to claim 1 , wherein the heat conducting layer (62) comprises graphite or graphene.

3. The cartridge (12) according to any one of the preceding claims, wherein the heat conducting layer (62) extends according to the whole area of the vaporizing surface (67) of the wick (60).

4. The cartridge (12) according to any one of the preceding claims, wherein the first surface (71 ) of the heat conducting layer (62) comprises an adhesive coating designed to adherer to the vaporizing surface (67) of the wick (60).

5. The cartridge (12) according to any one of the preceding claims, wherein the heat conducting layer (62) is sandwiched between the vaporizing surface (67) of the wick (60) and the heating surface (24) of the aerosol generating device (1 1 ) when the cartridge (12) is operating with the aerosol generating device (11 ) to generate aerosol.

6. The cartridge (12) according to any one of the preceding claims, wherein the vaporizing surface (67) of the wick (60) is a non-flat surface.

7. The cartridge (12) according to claim 6, wherein the vaporizing surface (67) forms at least one groove forming an airflow channel.

8. The cartridge (12) according to claim 6 or 7, wherein the vaporizing surface (67) of the wick (60) is arranged in fluid communication with an airflow path (52) conducting airflow to the outside of the cartridge (12).

9. The cartridge (12) according to claim 8, wherein the wick (60) defines a central hole delimiting partially the airflow path (52).

10. The cartridge (12) according to any one of the preceding claims, wherein the vaporizing surface (67) of the wick (60) is substantially perpendicular to its absorbing surface (65).

1 1. The cartridge (12) according to any one of the preceding claims, wherein the wick (60) is made of ceramics.

12. The cartridge (12) according to any one of the preceding claims, wherein the heat conducting layer (62) is liquid and advantageously gas impermeable.

13. An aerosol generating system (10), comprising:

- a cartridge (12) according to any one of the preceding claims;

- an aerosol generating device (11 ) configured to operate with said cartridge (12).

14. The aerosol generating system (10) according to claim 13, wherein the aerosol generating device (11 ) comprises a heater (22) forming a heating surface (24) designed to be in contact with the second surface (72) of the heat conducting layer (62) of the cartridge