WO2023071668A1

WO2023071668A1 - Heating assembly with side extensions

Info

Publication number: WO2023071668A1
Application number: PCT/CN2022/121696
Authority: WO
Inventors: Michel BESSANT; Jun Wei Yim; Xin ZHAN; Liu Liu
Original assignee: Philip Morris Products S.A.
Priority date: 2021-10-25
Filing date: 2022-09-27
Publication date: 2023-05-04
Also published as: WO2023070259A1

Abstract

The invention relates to a heating assembly for an aerosol-generating device, the heating assembly comprising a first substrate layer. The first substrate layer is an electrically isolating substrate layer. The aerosol-generating device further comprises a heating element. The heating element is arranged on the first substrate layer. The aerosol-generating device further comprises a second substrate layer. The second substrate layer is an electrically isolating substrate layer. The second substrate layer is arranged covering the heating element and the first substrate layer. The aerosol-generating device further comprises a temperature sensor. The temperature sensor is arranged on the second substrate layer. The aerosol-generating device further comprises a third substrate layer. The third substrate layer is an electrically isolating substrate layer. The third substrate layer is arranged at least partly covering the temperature sensor and covering the second substrate layer. One or more of the first substrate layer, the second substrate layer and the third substrate layer comprises a side extension at a short edge of the respective substrate layer. The invention further relates to an aerosol-generating device and to a method for manufacturing a heating assembly for an aerosol-generating device.

Description

HEATING ASSEMBLY WITH SIDE EXTENSIONS

The present invention relates to a heating assembly for an aerosol-generating device. The invention further relates to an aerosol-generating device and a method for manufacturing a heating assembly.

It is known to provide an aerosol-generating device for generating an inhalable vapor. Such devices may heat aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate are volatilised without burning the aerosol-forming substrate. Aerosol-forming substrate may be provided as part of an aerosol-generating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a cavity, such as a heating chamber, of the aerosol-generating device. A heating assembly may be arranged in or around the heating chamber for heating the aerosol-forming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device.

It would be desirable to have a heating assembly for an aerosol-generating device with improved reliability. It would be desirable to have a heating assembly for an aerosol-generating device with improved manufacturing quality. It would be desirable to have a heating assembly for an aerosol-generating device with improved robustness during manufacturing.

According to an embodiment of the invention there is provided a heating assembly for an aerosol-generating device, the heating assembly comprising a first substrate layer. The first substrate layer may be an electrically isolating substrate layer. The aerosol-generating device may further comprise a heating element. The heating element may be arranged on the first substrate layer. The aerosol-generating device may further comprise a second substrate layer. The second substrate layer may be an electrically isolating substrate layer. The second substrate layer may be arranged covering the heating element and the first substrate layer. The aerosol-generating device may further comprise a temperature sensor. The temperature sensor may be arranged on the second substrate layer. The aerosol-generating device may further comprise a third substrate layer. The third substrate layer may be an electrically isolating substrate layer. The third substrate layer may be arranged at least partly covering the temperature sensor and covering the second substrate layer. One or more of the first substrate layer, the second substrate layer and the third substrate layer may comprise a side extension at a short edge of the respective substrate layer.

According to an embodiment of the invention there is provided a heating assembly for an aerosol-generating device, the heating assembly comprising a first substrate layer. The first substrate layer is an electrically isolating substrate layer. The aerosol-generating device further comprises a heating element. The heating element is arranged on the first substrate layer. The aerosol-generating device further comprises a second substrate layer. The second substrate layer is an electrically isolating substrate layer. The second substrate layer is arranged covering the heating element and the first substrate layer. The aerosol-generating device further comprises a temperature sensor. The temperature sensor is arranged on the second substrate layer. The aerosol-generating device further comprises a third substrate layer. The third substrate layer is an electrically isolating substrate layer. The third substrate layer is arranged at least partly covering the temperature sensor and covering the second substrate layer. One or more of the first substrate layer, the second substrate layer and the third substrate layer comprises a side extension at a short edge of the respective substrate layer.

The term ‘covering’ or ‘cover’ may mean that a first layer has the substantial same surface size as a second layer so that the first layer can be placed on the second layer in a way that the surface area of the second layer facing the first layer is substantially overlapped by the first layer. In case a first layer is arranged covering a second layer, the surface size of the first layer may be at least 90 %of the surface area of the second layer, preferably the surface size of the first layer may be at least 80 %of the surface area of the second layer, more preferably the surface size of the first layer may be at least 70 %of the surface area of the second layer, most preferably the surface size of the first layer may be at least 60 %of the surface area of the second layer

The heating element may be sandwiched between the first substrate layer and the second substrate layer. The heating element may only cover a portion of the surface of the first substrate layer. When the second substrate layer is placed on the first substrate layer and on the heating element, the second substrate layer preferably covers the heating element and covers the rest of the surface of the first substrate layer on which the heating element is arranged and that is not covered by the heating element.

Similarly, the temperature sensor may be sandwiched between the second substrate layer and a third substrate layer. The temperature sensor may only cover a portion of the surface of the second substrate layer. When the third substrate layer is placed on the second substrate layer and on the temperature sensor, the third substrate layer preferably covers the temperature sensor and covers the rest of the surface of the second substrate layer on which the temperature sensor is arranged and that is not covered by the temperature sensor.

In the final heating assembly, the heating element and the temperature sensor are preferably arranged on opposite surfaces of the second substrate layer. Hence, the heating element is electrically isolated from the temperature sensor via the second substrate layer.

The heating element may be protected by the first substrate layer and by the second substrate layer.

The temperature sensor may be protected by the second substrate layer and by the third substrate layer.

Providing the side extension may improve the mounting of the heating assembly. For mounting the heating assembly in an aerosol-generating device, the heating assembly may be rolled. The rolling of the heating assembly may lead to a tubular heating assembly. The heating assembly may be rolled around a cavity of the aerosol-generating device as described in more detail below. The cavity may a stainless steel tube. The heating assembly may be attached to the tube exemplarily by an adhesive. However, without he side extensions, the only attachment between the rolled hearing assembly and the tube is the adhesive. This may not be sufficient to securely hold the hearing assembly on the tube. By providing the side extension, the rolled hearing assembly can be held in the rolled shape by the side extension. In more detail the side extension may be attached –after rolling of the heating assembly –to the opposite short edge of the respective layer in order to hold the heating assembly securely in the rolled shape. This may be done in addition or in place of providing an adhesive for attaching the rolled heating assembly to the tube of the aerosol-generating device forming the cavity.

The side extension may be flexible. This may enable to place the side extension on the opposite short edge of the respective layer after rolling of the heating assembly.

The side extension may be provided with an adhesive layer or coating to enable attachment of the side extension to the opposite short edge of the respective layer.

“Attachment to the opposite short edge of the respective layer” denotes attachment of the side extension in an area adjacent the opposite short edge of the respective layer. This area may abut the short edge. This area may have a surface dimensioned similar to the surface of the side extension. This area may have a surface area dimensioned similar to the surface area of the side extension. This area may have a surface area corresponding to the surface area of the side extension. After attachment of the side extension to the opposite short edge of the respective layer, the short edges of the respective layer may abut each other. The heating assembly may thus have a tubular shape after rolling and attachment of the side extension to the opposite short edge of the respective layer.

Two or three of the first substrate layer, the second substrate layer and the third substrate layer may comprise a side extension at a short edge of the respective substrate layer.

All three of the first substrate layer, the second substrate layer and the third substrate layer may comprise a side extension at a short edge of the respective substrate layer.

In all of these cases, the respective side extension may be attached to the opposite short edge of the respective layer as described herein.

Exemplarity, the first substrate layer may comprise a first side extension at a first short edge of the first substrate layer. This first side extension may be configured to be attached to a second short edge of the first substrate layer opposite the first short edge of the first substrate layer. The second substrate layer may comprise a second side extension at a first short edge of the second substrate layer. This second side extension may be configured to be attached to a second short edge of the second substrate layer opposite the first short edge of the second substrate layer. The third substrate layer may comprise a third side extension at a first short edge of the third substrate layer. This third side extension may be configured to be attached to a second short edge of the third substrate layer opposite the first short edge of the third substrate layer.

Providing more than one side extension and preferably three side extensions as described herein may improve the attachment of the substrate layers after rolling of the heating assembly.

The side extensions of the substrate layers may have the same dimensions. This may make the attachment of the side extension to the respective opposite short edge of the respective substrate layer easier.

The side extensions may be stacked over each other.

The side extension may be integrally formed with the respective substrate layer. In other words, one or more of: the first side extension may be integrally formed with the first substrate layer, the second side extension may be integrally formed with the second substrate layer and the third side extension may be integrally formed with the third substrate layer.

One or more of: the first side extension may be arranged at a first short edge of the first substrate layer, the second side extension may be arranged at a first short edge of the second substrate layer and the third side extension may be arranged at a first short edge of the third substrate layer.

One or more of the first substrate layer, the second substrate layer and the third substrate layer may have a rectangular shape.

The term “short edge” denotes an edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer that is shorter than a further edge of the respective layer.

In case of a rectangular layer, two opposing short edges are connected via two opposing long edges. The length of a short edge is smaller than the length of a long edge.

The side extension may extends over at least 70%, preferably may extends over at least 80%, more preferably may extends over at least 90%, more preferably may extends over the full length, of the short edge of the respective substrate layer.

The respective substrate layer comprising the side extension may comprise an attachment area at an opposite short edge of the respective substrate layer.

The surface area of the attachment area may be essentially identical, preferably identical, to the surface area of the side extension.

The attachment area may abut the short edge of the respective substrate layer. In other words, the attachment area may be arranged directly adjacent the respective substrate layer.

The length of the side extension may be larger than the width of the side extension by a factor of 1.5, preferably by a factor of 2.0, more preferably by a factor of 2.5, most preferably by a factor of at least 3.

The side extension may have an elongate shape.

The side extension may have a rectangular shape.

The side extension may be longer than wide.

The side extension may be thinner than wide.

The side extension may be thinner than long.

The side extension may have a length of between 5 mm and 20 mm, preferably between 8 mm and 15 mm, more preferably between 10 mm and 14 mm, most preferably of 12 mm.

The side extension may have a width of between 2 mm and 6 mm, preferably between 3 mm and 5 mm, more preferably of 4 mm.

A long edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer may have a length of between 16 mm and 32 mm, preferably between 19 mm and 29 mm, more preferably between 22 mm and 26 mm, most preferably of 24 mm.

Only the first substrate layer, the second substrate layer or the third substrate layer may comprise the side extension. This may make attachment of the side extension to the opposite short edge easier as only a single side extension may need to be attached. This may also be sufficient as the first, second and third substrate layers may be attached to each other as described herein, preferably by adhesive layers. A single side extension may thus be sufficient to attach the first substrate layer, the second substrate layer and the third substrate layer together into a tubular shape.

The heating assembly may further comprise anchoring legs. The anchoring legs may be arranged at a long edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer.

The anchoring legs may function to attach the heating assembly to the cavity of the aerosol-generating assembly.

The heating element may comprise heater contacts. The heater contacts may be arranged on the anchoring legs.

The anchoring legs may form a support for the heater contacts. The anchoring legs may be arranged to enable attachment of the heater contacts with electrical components of the aerosol-generating device. The electrical components may include a controller and a power supply.

The heating element may be a resistive heater. The heating element may comprise a heating track. The heating element may be a heating track. The heating tracks may be configured to generate heat. The heating tracks may be electrically resistive heating tracks. The heating elements may comprise electrical contacts for electrically contacting the heating tracks. The electrical contacts may be attached to the heating tracks by any known means, exemplarily by soldering or welding. A first electrical contact may be attached to a first end of the heating tracks and a second electrical contact may be attached to a second end of the heating tracks. The first end of the heating tracks may be a proximal end of the heating tracks and the second end of the heating tracks may be a distal end of the heating tracks or vice versa.

The heating tracks may be made from stainless-steel. The heating tracks may be made from stainless-steel at about 50 μm thickness. The heating tracks may be preferably made from stainless-steel at about 25 μm thickness. The heating tracks may be made from inconel at about 50.8 μm thickness. The heating tracks may be made from inconel at about 25.4 μm thickness. The heating tracks may be made from copper at about 35 μm thickness. The heating tracks may be made from constantan at about 25 μm thickness. The heating tracks may be made from nickel at about 12 μm thickness. The heating tracks may be made from brass at about 25 μm thickness.

The heating element may be printed on the first substrate layer. The heating tracks may be photo-printed on the substrate layer. The heating tracks may be chemically etched on the substrate layer.

The term ‘heating tracks’ encompasses a single heating track. The heating element or the heating tracks may be printed on the first substrate layer.

The heating tracks may be centrally arranged on the first substrate layer. The heating tracks may have a bent shape. The heating tracks may have a curved shape. The heating tracks may have a zigzag shape. This heating tracks may have a winding shape.

The heating assembly may be rolled into a tube. The heating tracks may be flat before the substrate layer is rolled into the tubular shape. The heating tracks or the heating element may be flexible. The heating tracks or the heating element may conform to the tubular shape of the substrate layer when the substrate layer is rolled into the tubular shape.

The temperature sensor may comprise two contacts.

The third substrate layer may comprise at least two openings. The two openings are provided for enabling the electrical contacts of the temperature sensor to be contacted through the third substrate layer.

The two openings may be aligned such that the two contacts are not covered by the third substrate layer. The two openings may be arranged adjacent to opposite ends of the third substrate layer. The two openings may correspond to the placement of electrical contacts on the temperature sensor.

In addition to the two openings, a further opening may be provided in the third substrate layer. The third opening may be arranged centrally in the third substrate layer. This third opening may increase the mechanical strength of the third substrate layer in this area. Particularly, the opening in the middle of the third substrate layer may strengthen the fixation of the electrical wires contacting the electrical contacts of the temperature sensor, since the electrical wires come into contact with the underlying adhesive layer of the second substrate layer in this area.

The electrical contacts of the temperature sensor may be attached to the temperature sensor by any known means, exemplarily by soldering or welding. A first electrical contact may be attached to a first end of the temperature sensor and a second electrical contact may be attached to a second end of the temperature sensor. The first end of the temperature sensor may be a proximal end of the temperature sensor and the second end of the temperature sensor may be a distal end of the temperature sensor or vice versa.

The temperature sensor may comprise temperature sensor tracks.

A heat shrink layer may be arranged around the heating assembly. The heat shrink layer may be made of PEEK. The heat shrink layer may be arranged around the heating assembly when the heating assembly is rolled into the tubular shape. The heat shrink layer may be configured to shrink when heated. The heat shrink layer may securely hold the heating assembly together. The heat shrink layer may be configured to apply a uniform inwards pressure to the heating assembly. The heat shrink layer may improve the contact between one or both of the tube and the first substrate layer and the second substrate layer and the third substrate layer. The heat shrink layer may hold most or all components of the heating assembly tight together. The heat shrink layer may be employed to replace the glue layers or adhesive layers described herein. Alternatively, the heat shrink layer may be employed in addition to the glue layers or adhesive layers described herein.

The thickness of the heat shrink layer may be between 100 μm and 300 μm, preferably around 180 μm.

The heat shrink layer may be made of PEEK. The heat shrink layer may be made of or comprise one or more of Teflon and PTFE.

The heating assembly may comprise a tube, preferably a metal tube, around which the substrate layer may be wrapped or rolled. The metal tube is preferable a stainless-steel tube. Alternatively, the tube may be a ceramic tube. The tube may define the tubular shape of the heating assembly. The outer diameter of the tube may correspond to the inner diameter of the first substrate layer after rolling of the substrate layer.

The heating assembly may further comprise a heating chamber conformed by the tubular shape of the heating assembly. The substrate layers together with the heating element and the temperature sensor may be rolled to conform the tube forming the heating chamber. In this configuration, the first substrate layer may form the inner layer facing the tube and the third substrate layer may be the outer layer. The first substrate layer may be adjacent the metal tube forming the innermost layer of the heating assembly.

The tube may be made from stainless-steel. The tube may have a length of between 10 mm and 35 mm, preferably between 12 mm and 30 mm, preferably between 13 mm and 22 mm. The tube may be a hollow tube. The hollow tube may have an internal diameter of between 4 mm and 9 mm, preferably between 5 mm and 6 mm or between 6.8 mm and 7.5 mm, preferably around 5.35 mm or around 7.3 mm. The tube may have a thickness of between 70 μm and 110 μm, preferably between 80 μm and 100 μm, preferably around 90 μm. The tube may have a cylindrical cross-section. The tube may have a circular cross-section.

The length of the first substrate layer may be equal to or less than the circumference of the tube. The first substrate layer may fully wrap around the tube. The first substrate layer may wrap around the tube once such that the surface of the tube is covered by the first substrate layer after the first substrate layer has been wrapped around the tube.

The tube of the heating chamber may have a thickness of between 70 μm and 110 μm, preferably between 80 μm and 100 μm, preferably around 90 μm.

The temperature sensor may be an NTC, a Pt100 or preferably a Pt1000 temperature sensor. The temperature sensor may be attached to the second substrate layer by means of an adhesive layer. The temperature sensor may be photo-printed onto the second substrate layer. Chemical etching may be utilized for forming one or both of the heating tracks of the heating element and the temperature sensor tracks. Subsequently, the contacts of the temperature sensor may be welded on the temperature sensor tracks through the openings in the third substrate layer.

The temperature sensor may be positioned on the second substrate layer such that when the heating assembly is rolled up, the temperature sensor may be positioned in an area corresponding to the centre of the first substrate layer. By positioning the temperature sensor in this way, the heating element may be mapping the temperature sensor so that the temperature sensor is positioned adjacent the hottest part of the heating element. The hottest part adjacent the temperature sensor may be the centre of the first substrate layer. The heating element may be arranged at the center of the first substrate layer. The temperature sensor may be arranged directly adjacent the heating element only distanced from the heating element by the thickness of the second substrate layer.

One or more of the substrate layers may have a thickness of between 10 μm and 50 μm, preferably between 20 μm and 30 μm, more preferably around 25 μm.

The heating element may, when preferably made of stainless-steel, have a thickness of between 20 μm and 60 μm, preferably between 30 μm and 50 μm, more preferably around 40 μm. The heating tracks may, when preferably made of stainless-steel, have a thickness of between 20 μm and 60 μm, preferably between 30 μm and 50 μm, more preferably around 40 μm.

One or more of:

a first adhesive layer may be provided between the first substrate layer and the heating element,

a second adhesive layer may be provided between the heating element and the second substrate layer,

a third adhesive layer may be provided between the second adhesive layer and the temperature sensor, and

a fourth adhesive layer may be provided between the temperature sensor and the third substrate layer.

The first adhesive layer may facilitate attachment between the first substrate layer and the heating element. The first adhesive layer may further facilitate attachment between the first substrate layer and the second substrate layer in the area of the first substrate layer not covered by the heating element. The second adhesive layer may facilitate attachment between the heating element and the second substrate layer. The third adhesive layer may facilitate attachment between the second substrate layer and the temperature sensor. The third adhesive layer may further facilitate attachment between the second substrate layer and the third substrate layer in the area of the third adhesive layer not covered by the temperature sensor. The fourth adhesive layer may facilitate attachment between the temperature sensor and the third substrate layer.

One or more of the adhesive layers may have a thickness of between 2 μm and 10 μm, preferably between 3 μm and 7 μm, more preferably around 5 μm.

One or more of the adhesive layers may be a silicon-based adhesive layer. The adhesive layer may comprise one or both of PEEK-based adhesives and acrylic adhesives.

One or more of the first substrate layer, the second substrate layer and the third substrate layer may comprise a polyamide film. Any of the substrate layers may be made from polyimide or polyamide. The substrate layers may be configured to withstand between 220 ℃ and 320 ℃, preferably between 240 ℃ and 300 ℃, preferably around 280 ℃. Any of the substrate layers may be made from Pyralux.

The invention further relates to an aerosol-generating device comprising the heating assembly as described herein.

The aerosol-generating device may comprise a cavity for receiving an aerosol-generating article. The heating assembly may be arranged at least partly surrounding the cavity.

A sidewall of the cavity may be formed of a stainless-steel tube. The heating assembly may be mounted on the stainless-steel tube. The heating assembly may form the cavity as described in more detail herein.

The invention further relates to a method for manufacturing a heating assembly for an aerosol-generating device, the method comprising one or more of the following steps:

providing a first substrate layer, the first substrate layer being an electrically isolating substrate layer,

arranging a heating element on the first substrate layer,

arranging a second substrate layer covering the heating element and the first substrate layer, the second substrate layer being an electrically isolating substrate layer,

arranging a temperature sensor on the second substrate layer,

arranging a third substrate layer at least partly covering the temperature sensor and covering the second substrate layer, the third substrate layer being an electrically isolating substrate layer, and

providing one or more of the first substrate layer, the second substrate layer and the third substrate layer with a side extension at a short edge of the respective substrate layer.

As used herein, the terms “upstream” and “downstream” , are used to describe the relative positions of components, or portions of components, of the aerosol generating device in relation to the direction in which airflows through the aerosol generating device during use thereof. Aerosol generating devices according to the invention comprise a proximal end through which, in use, an aerosol exits the device. The proximal end of the aerosol generating device may also be referred to as the mouth end or the downstream end. The mouth end is downstream of the distal end. The distal end of the aerosol generating article may also be referred to as the upstream end. Components, or portions of components, of the aerosol generating device may be described as being upstream or downstream of one another based on their relative positions with respect to the airflow path of the aerosol generating device.

In all of the aspects of the disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide) , carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics.

As described, in any of the aspects of the disclosure, the heating element may comprise an external heating element, where "external" refers to the aerosol-forming substrate. An external heating element may take any suitable form. For example, an external heating element may take the form of one or more flexible heating foils or heating tracks on a dielectric substrate, such as polyimide. The dielectric substrate is the substrate layer. The flexible heating foils or heating tracks can be shaped to conform to the perimeter of the heating chamber. Alternatively, an external heating element may take the form of a metallic grid or grids, a flexible printed circuit board, a molded interconnect device (MID) , ceramic heater, flexible carbon fibre heater or may be formed using a coating technique, such as plasma vapour deposition, on the suitable shaped substrate layer. An external heating element may also be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between the first substrate layer and the second substrate layer. An external heating element formed in this manner may be used to both heat and monitor the temperature of the external heating element during operation.

The heating element advantageously heats the aerosol-forming substrate by means of conduction. Alternatively, the heat from either an internal or external heating element may be conducted to the substrate by means of a heat conductive element.

During operation, the aerosol-forming substrate may be completely contained within the aerosol-generating device. In that case, a user may puff on a mouthpiece of the aerosol-generating device. Alternatively, during operation a smoking article containing the aerosol-forming substrate may be partially contained within the aerosol-generating device. In that case, the user may puff directly on the smoking article.

The heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. In general, a susceptor is a material that is capable of generating heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several induction coils heat the susceptor, which then transfers the heat to the aerosol-forming substrate, such that an aerosol is formed. The heat transfer may be mainly by conduction of heat. Such a transfer of heat is best, if the susceptor is in close thermal contact with the aerosol-forming substrate. When an induction heating element is employed, the induction heating element may be configured as an external heater as described herein. If the induction heating element is configured as an external heating element, the susceptor element is preferably configured as a cylindrical susceptor at least partly surrounding the heating chamber. The heating tracks described herein may be configured as a susceptor. The susceptor may be arranged between the first substrate layer and the second substrate layer. The second portion of the substrate layer may be surrounded by the induction coil. The susceptor as well as the induction coil may be part of the heating assembly.

Preferably, the aerosol-generating device comprises a power supply configured to supply power to the one or both of the heating element and the heating assembly. The power supply preferably comprises a power source. Preferably, the power source is a battery, such as a lithium ion battery. As an alternative, the power source may be another form of charge storage device such as a capacitor. The power source may require recharging. For example, the power source may have sufficient capacity to allow for the continuous generation of aerosol for a period of around six minutes or for a period that is a multiple of six minutes. In another example, the power source may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the heating assembly.

The aerosol-generating device may comprise control electronics. The control electronics may comprise a microcontroller. The microcontroller is preferably a programmable microcontroller. The electric circuitry may comprise further electronic components. The electric circuitry may be configured to regulate a supply of power to the heating assembly. Power may be supplied to the heating assembly continuously following activation of the system or may be supplied intermittently, such as on a puff-by-puff basis. The power may be supplied to the heating assembly in the form of pulses of electrical current.

The control electronics may comprise a printed circuit board. The control electronics may be configured as a printed circuit board.

The temperature sensor may be electrically connected with the control electronics. The length of the electrical connections between the temperature sensor and the control electronics may be longer than the distance between the temperature sensor and the control electronics. This may have the beneficial effect of preventing a detrimental effect on the electrical contact between the temperature sensor and the control electronics due to thermal expansion of the contacts during operation of the aerosol-generating device. The electrical connections are preferably configured as electrical wires.

Similarly, the length of the electrical connections between the heating element and the control electronics may be longer than the distance between the heating element and the control electronics. This may have the beneficial effect of preventing a detrimental effect on the electrical contact between the heating element and the control electronics due to thermal expansion of the contacts during operation of the aerosol-generating device. The electrical connections are preferably configured as electrical wires.

As used herein, the term “aerosol-forming substrate” refers to a substrate capable of releasing volatile compounds that can form an aerosol. The volatile compounds may be released by heating or combusting the aerosol-forming substrate. As an alternative to heating or combustion, in some cases, volatile compounds may be released by a chemical reaction or by a mechanical stimulus, such as ultrasound. The aerosol-forming substrate may be solid or liquid or may comprise both solid and liquid components. An aerosol-forming substrate may be part of an aerosol-generating article.

As used herein, the term “aerosol-generating article” refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. An aerosol-generating article may be disposable.

As used herein, the term “aerosol-generating device” refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. An aerosol-generating device may interact with one or both of an aerosol-generating article comprising an aerosol-forming substrate, and a cartridge comprising an aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate release of volatile compounds from the substrate. An electrically operated aerosol-generating device may comprise an atomiser, such as an electric heater, to heat the aerosol-forming substrate to form an aerosol.

As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of the aerosol-generating device with the aerosol-generating article. In the aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device cooperate to generate an aerosol.

Below, there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Ex1. A heating assembly for an aerosol-generating device, the heating assembly comprising:

a first substrate layer, the first substrate layer being an electrically isolating substrate layer,

a heating element, wherein the heating element is arranged on the first substrate layer,

a second substrate layer, the second substrate layer being an electrically isolating substrate layer, wherein the second substrate layer is arranged covering the heating element and the first substrate layer,

a temperature sensor, wherein the temperature sensor is arranged on the second substrate layer,

a third substrate layer, the third substrate layer being an electrically isolating substrate layer, wherein the third substrate layer is arranged at least partly covering the temperature sensor and covering the second substrate layer,

wherein one or more of the first substrate layer, the second substrate layer and the third substrate layer comprises a side extension at a short edge of the respective substrate layer.

Ex2. The heating assembly according to example ex1, wherein two or three of the first substrate layer, the second substrate layer and the third substrate layer comprise a side extension at a short edge of the respective substrate layer.

Ex3. The heating assembly according to any of the preceding examples, wherein all three of the first substrate layer, the second substrate layer and the third substrate layer comprise a side extension at a short edge of the respective substrate layer.

Ex4. The heating assembly according to example ex2 or ex3, wherein the side extensions of the substrate layers have the same dimensions.

Ex5. The heating assembly according to any one of examples ex2 to ex4, wherein the side extensions are stacked over each other.

Ex6. The heating assembly according to any of the preceding examples, wherein the side extension is integrally formed with the respective substrate layer.

Ex7. The heating assembly according to any of the preceding examples, wherein the side extension extends over at least 70%, preferably extends over at least 80%, more preferably extends over at least 90%, more preferably extends over the full length, of the short edge of the respective substrate layer.

Ex8. The heating assembly according to any of the preceding examples, wherein the respective substrate layer comprising the side extension comprises an attachment area at an opposite short edge of the respective substrate layer.

Ex9. The heating assembly according to example ex5, wherein the surface area of the attachment area is essentially identical, preferably identical, to the surface area of the side extension.

Ex10. The heating assembly according to any of the preceding examples, wherein the length of the side extension is larger than the width of the side extension by a factor of 1.5, preferably by a factor of 2.0, more preferably by a factor of 2.5, most preferably by a factor of at least 3.

Ex11. The heating assembly according to any of the preceding examples, wherein the side extension has a length of between 5 mm and 20 mm, preferably between 8 mm and 15 mm, more preferably between 10 mm and 14 mm, most preferably of 12 mm.

Ex12. The heating assembly according to any of the preceding examples, wherein the side extension has a width of between 2 mm and 6 mm, preferably between 3 mm and 5 mm, more preferably of 4 mm.

Ex13. The heating assembly according to any of the preceding examples, wherein a long edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer has a length of between 16 mm and 32 mm, preferably between 19 mm and 29 mm, more preferably between 22 mm and 26 mm, most preferably of 24 mm.

Ex14. The heating assembly according to any of examples ex1 and ex3 to ex13, wherein only the first substrate layer, the second substrate layer or the third substrate layer comprises the side extension.

Ex15. The heating assembly according to any of the preceding examples, wherein the heating assembly further comprises anchoring legs, and wherein the anchoring legs are arranged at a long edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer.

Ex16. The heating assembly according to any of the preceding examples, wherein the heating element is a resistive heater.

Ex17. The heating assembly according to the two preceding examples, wherein the heating element comprises heater contacts, and wherein the heater contacts are arranged on the anchoring legs.

Ex18. The heating assembly according to any of the preceding examples, wherein the heating element comprise a heating track, preferably wherein the heating element is a heating track.

Ex19. The heating assembly according to any of the preceding examples, wherein the heating element is printed on the first substrate layer.

Ex20. The heating assembly according to any of the preceding examples, wherein the heating assembly is rolled into a tube.

Ex21. The heating assembly according to any of the preceding examples, wherein the temperature sensor comprises two contacts.

Ex22. The heating assembly according to any of the preceding examples, wherein the third substrate layer comprises at least two openings.

Ex23. The heating assembly according to the two preceding examples, wherein the two openings are aligned such that the two contacts are not covered by the third substrate layer.

Ex24. The heating assembly according to any of the preceding examples, wherein a heat shrink layer is arranged around the heating assembly, wherein the heat shrink layer is preferably made of PEEK.

Ex25. The heating assembly according to any of the preceding examples, wherein one or more of:

- a first adhesive layer is provided between the first substrate layer and the heating element,

- a second adhesive layer is provided between the heating element and the second substrate layer,

- a third adhesive layer is provided between the second adhesive layer and the temperature sensor, and

- a fourth adhesive layer is provided between the temperature sensor and the third substrate layer.

Ex26. The heating assembly according to any of the preceding examples, wherein one or more of the first substrate layer, the second substrate layer and the third substrate layer comprise a polyamide film.

Ex27. An aerosol-generating device comprising the heating assembly according to any of the preceding examples.

Ex28. The aerosol-generating device according to the preceding example, wherein the aerosol-generating device comprises a cavity for receiving an aerosol-generating article, and wherein the heating assembly is arranged at least partly surrounding the cavity.

Ex29. The aerosol-generating device according to the preceding example, wherein a sidewall of the cavity is formed of a stainless-steel tube, and wherein the heating assembly is mounted on the stainless-steel tube.

Ex30. A method for manufacturing a heating assembly for an aerosol-generating device, the method comprising the steps of:

arranging a heating element on the first substrate layer,

arranging a temperature sensor on the second substrate layer,

Features described in relation to one embodiment may equally be applied to other embodiments of the invention.

The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 shows the heating assembly;

Fig. 2 shows layers making up the heating assembly;

Fig. 3 shows layers making up the heating assembly including a third insulating layer;

Fig. 4 shows a different perspective of the heating assembly and particularly the electrical connections; and

Fig. 5 shows substrate layers of the heating assembly having side extensions.

Figure 1 shows a heating assembly 10. The heating assembly 10 comprises a stainless-steel tube 12. The stainless-steel tube 12 forms the inner layer of the heating assembly 10. The stainless-steel tube 12 is tubular. The stainless-steel tube 12 forms a heating chamber 14 such that an aerosol-generating article comprising aerosol forming substrate can be placed in the heating chamber 14 to heat the aerosol-forming substrate and to create an inhalable aerosol.

Figure 1 further shows a first substrate layer 16. On top of the first substrate layer 16, a heating element 18 in the form of heating tracks is arranged. Electrical heater contacts 20 of the heating element 18 also indicated in Figure 1. On the first substrate layer 16, a first adhesive layer 22 is arranged for an attachment between the first substrate layer 16 and the heating element 18. Additionally, the surface area of the first substrate layer 16 not covered with the heating element 18 may be attached to the second substrate layer 24 via the first adhesive layer 22.

Figure 1 further shows the second substrate layer 24. On the second substrate layer 24, a second adhesive layer 26 is arranged. The second adhesive layer 26 has the function of enabling an attachment between the second substrate layer 24 and a temperature sensor 28. The second adhesive layer 26 further facilitates the attachment between the second substrate layer 24 and sensor contacts 30 of the temperature sensor 28. Finally, the second adhesive layer 26 facilitates the attachment between the second substrate layer 24 and a third substrate layer 38. The third substrate layer 38 is arranged over the temperature sensor 28 as described in more detail below with reference to Figure 3. The third substrate layer 38 is not depicted in Figure 1. Finally, a heat shrink layer 32 is placed over the heating assembly 10. Heating of the heat shrink layer 32 facilitates a secure holding of all components of the heating assembly 10.

Figure 2 shows the layers of the heating assembly 10 in more detail. The inner layers formed by the stainless-steel tube 12. A tube adhesive layer 34 is utilized to connect the stainless-steel tube 12 with the first substrate layer 16. As a next layer, the heating element 18 is arranged on the first substrate layer 16 versus the first adhesive layer 22. Between the heating element 18 and the second substrate layer 24, a heater adhesive layer 36 is arranged. Finally, the temperature sensor 28 is arranged on the second substrate layer 24 via the second adhesive layer 26.

Figure 2 further shows the preferred thicknesses of all layers.

Figure 3 shows the additional placement of a third substrate layer 38 over the temperature sensor 28 via a sensor adhesive layer 40. In the third substrate layer 38 at least two openings 42 are provided to enable sensor contacts 30 to be contacted through the third substrate layer 38. Figure 3 further shows the preferred thicknesses of all layers.

Figure 4 shows a different perspective of the heating assembly 10 seen from the top and before the heating assembly 10 is rolled into a tubular shape.

The heating tracks of the heating element 18 are depicted in Figure 4. Two heater contacts 20 are provided to enable the supply of electrical energy to the heating element 18. Further, two sensor contacts 30 are provided for electrically contacting the temperature sensor 28.Openings in the third substrate layer 38 are indicated in Figure 4 which enable contacting the temperature sensor 28 via the sensor contacts 30. Further, Figure 4 indicates a third opening in the middle of the third substrate layer 38 to increase the mechanical strength of the connections of the temperature sensor 28, since the contacts can come into contact with the sensor adhesive layer 40 through this opening.

Figure 5 shows the first substrate layer 16, the second substrate layer 24 and the third substrate layer 38 before attachment of the layers and before attachment of the heating element 18 and of the temperature sensor 28.

Figure 5 further shows a first side extension 44 of the first substrate layer 16, a second side extension 46 of the second substrate layer 24 and a third side extension 48 of the third substrate layer 38.

The first side extension 44 is arranged at a first short edge 50 of the first substrate layer 16.The second side extension 46 is arranged at a first short edge 52 of the second substrate layer 24. The third side extension 48 is arranged at a first short edge 54 of the third substrate layer 38.

The first side extension 44 can be attached to a first attachment area 56 which is arranged adjacent an opposite short edge of the first substrate layer 16. The second side extension 46 can be attached to a second attachment area 58 which is arranged adjacent an opposite short edge of the second substrate layer 24. The third side extension 48 can be attached to a third attachment area 60 which is arranged adjacent an opposite short edge of the third substrate layer 38.

The first side extension 44 is shorter than the first attachment area 56. The second side extension 46 is shorter than the second attachment area 58. The third side extension 48 is shorter than the third attachment area 60. As a consequence, a step area 62 is created in which the respective short edge extends over the respective side extension.

Figure 5 also shows attachment legs 64. The attachment legs are provided such that heater contacts of the heating element 18 can be arranged on the attachment legs 64. The heater contacts can be attached to electrical components of the aerosol-generating device such as a controller or a power supply.

Claims

A heating assembly for an aerosol-generating device, the heating assembly comprising:

a first substrate layer, the first substrate layer being an electrically isolating substrate layer,

a heating element, wherein the heating element is arranged on the first substrate layer,

a second substrate layer, the second substrate layer being an electrically isolating substrate layer, wherein the second substrate layer is arranged covering the heating element and the first substrate layer,

a temperature sensor, wherein the temperature sensor is arranged on the second substrate layer,

a third substrate layer, the third substrate layer being an electrically isolating substrate layer, wherein the third substrate layer is arranged at least partly covering the temperature sensor and covering the second substrate layer,

wherein one or more of the first substrate layer, the second substrate layer and the third substrate layer comprises a side extension at a short edge of the respective substrate layer.
The heating assembly according to claim 1, wherein all three of the first substrate layer, the second substrate layer and the third substrate layer comprise a side extension at a short edge of the respective substrate layer.
The heating assembly according to any of the preceding claims, wherein the side extensions are stacked over each other.
The heating assembly according to any of the preceding claims, wherein the side extension extends over at least 70%, preferably extends over at least 80%, more preferably extends over at least 90%, more preferably extends over the full length, of the short edge of the respective substrate layer.
The heating assembly according to any of the preceding claims, wherein the respective substrate layer comprising the side extension comprises an attachment area at an opposite short edge of the respective substrate layer.
The heating assembly according to claim 5, wherein the surface area of the attachment area is essentially identical, preferably identical, to the surface area of the side extension.
The heating assembly according to any of the preceding claims, wherein the side extension has a length of between 5 mm and 20 mm, preferably between 8 mm and 15 mm, more preferably between 10 mm and 14 mm, most preferably of 12 mm.
The heating assembly according to any of the preceding claims, wherein the side extension has a width of between 2 mm and 6 mm, preferably between 3 mm and 5 mm, more preferably of 4 mm.
The heating assembly according to any of claims 1 and 3 to 8, wherein only the first substrate layer, the second substrate layer or the third substrate layer comprises the side extension.
The heating assembly according to any of the preceding claims, wherein the heating assembly further comprises anchoring legs, and wherein the anchoring legs are arranged at a long edge of one or more of the first substrate layer, the second substrate layer and the third substrate layer.
The heating assembly according to any of the preceding claims, wherein the heating element comprise a heating track, preferably wherein the heating element is a heating track.
The heating assembly according to any of the preceding claims, wherein the heating element is printed on the first substrate layer.
The heating assembly according to any of the preceding claims, wherein the heating assembly is rolled into a tube.
The aerosol-generating device according to the preceding claim, wherein a sidewall of the cavity is formed of a stainless-steel tube, and wherein the heating assembly is mounted on the stainless-steel tube.
A method for manufacturing a heating assembly for an aerosol-generating device, the method comprising the steps of:

providing a first substrate layer, the first substrate layer being an electrically isolating substrate layer,

arranging a heating element on the first substrate layer,

arranging a second substrate layer covering the heating element and the first substrate layer, the second substrate layer being an electrically isolating substrate layer,

arranging a temperature sensor on the second substrate layer,

arranging a third substrate layer at least partly covering the temperature sensor and covering the second substrate layer, the third substrate layer being an electrically isolating substrate layer, and

providing one or more of the first substrate layer, the second substrate layer and the third substrate layer with a side extension at a short edge of the respective substrate layer.