TW202231199A - Heating assembly for an aerosol generating device - Google Patents

Abstract

A heating assembly (200) for an aerosol generating device (100) is disclosed. The heating assembly (200) comprises a metal tubular heating chamber (202) comprising an opening (204) for receiving an aerosol substrate. A coating of electrically insulating material (206) at least partially surrounds an outer surface (203) of the heating chamber (202), wherein the coating of electrically insulating material (206) comprises one or more of: ceramic; glass; silicone; and carbon. A heating element (208) at least partially surrounds the heating chamber and is disposed against the coating of electrically insulating material (206), wherein the coating of electrically insulating material (206) prevents any contact between the heating element (208) and the heating chamber (202).

Description

Heating components for aerosol generating devices

The present invention relates to a heating element for an aerosol generating device and a method of manufacturing a heating element for an aerosol generating device. The present disclosure is particularly applicable to portable aerosol generating devices, which may be self-contained and cryogenic. Such a device may generate an aerosol for inhalation by heating, rather than burning, tobacco or other suitable aerosol matrix material by conduction, convection, and/or radiation.

The use and popularity of risk-reduced or risk-modified devices (also known as vaporizers) have grown rapidly over the past few years, helping those who want to quit using traditional tobacco such as cigarettes, cigars, cigarillos, and cigarettes Habitual smokers of the product. Various devices and systems are available that heat or elevate the aerosolizable material other than burning tobacco in conventional tobacco products.

A common risk-reduced or risk-modified device is a heated matrix aerosol-generating device or a heat-not-burn device. Devices of this type generate an aerosol or vapor by heating an aerosol substrate (ie, consumable), typically comprising moist tobacco leaf or other suitable of aerosolizable materials. Heating the aerosol matrix without burning or burning it releases an aerosol that includes the components sought by the user but does not include undesired combustion by-products. Furthermore, aerosols produced by heating tobacco or other aerosolizable materials typically do not contain burnt or bitter tastes that may result from combustion that may be unpleasant to the user.

In known heat-and-burn devices, it is desirable to increase the efficiency of the heating process while keeping the device compact and reliable in operation.

According to a first aspect of the present invention, there is provided a heating assembly for an aerosol generating device, the heating assembly comprising: a metal tubular heating chamber including an opening for receiving an aerosol substrate; electrically insulating a coating of material that at least partially surrounds the outer surface of the heating chamber, wherein the electrically insulating layer includes one or more of: ceramic; glass; silicone; and carbon; and a heating element that heats The element at least partially surrounds the heating chamber and is positioned against a coating of electrically insulating material, wherein the coating of electrically insulating material prevents any contact between the heating element and the heating chamber.

In this way, a more efficient heating assembly is provided compared to known aerosol generating devices. The arrangement and properties of the electrically insulating material coating prevent short circuits from occurring between the metallic heating chamber and the heating element, while enabling improved heat transfer from the heating element to the aerosol matrix received within the heating chamber. In particular, the use of ceramic, glass, silicone and/or carbon as coating material provides high electrical breakdown voltages, eg 1000 V/mm, making it possible to use only thin layers of coating (eg 10 µm) to prevent short circuits, while also High thermal conductivity is provided to ensure efficient heat transfer to the heating chamber through the electrically insulating coating. In contrast, in known devices a separate (ie different) electrical insulating film, such as PEEK or polyimide, is usually provided between the heating element and the heating chamber. This adds complexity to the device and provides low thermal conductivity, which increases the time required to heat the heating chamber and reduces heating efficiency. The present invention eliminates the need for such a membrane, while also improving heat transfer characteristics, thereby increasing the efficacy of the heating element. Furthermore, the use of a coating rather than a separate electrically insulating film greatly simplifies the manufacturing process.

The term "coating" refers to a layer formed during the application of an electrically insulating material to the outer surface of a heating chamber. The coating does not exist as a discrete layer until it is applied. In particular, a coating can be defined as a layer formed by applying a liquid, vapor or gaseous material to the outer surface of the heating chamber. This is in stark contrast to films such as PEEK or polyimide films, which are pre-formed and exist as discrete layers prior to their application.

Preferably, the electrically insulating coating is formed as a rigid layer on the outer surface of the heating chamber. In contrast, traditional electrical insulating films such as PEEK or polyimide are attached as flexible layers on the outer surface of the heating chamber.

Preferably, the electrically insulating material coating is formed using one of the following: vapor deposition; painting; dipping; or spraying. In this way, the electrically insulating material coating exhibits advantageous mechanical and electrical properties compared to films of electrically insulating material (eg, polyimide films) that are preformed and then attached to the outer surface of the heating chamber. For example, a coating of electrically insulating material conforms to the specific morphology of the outer surface of the heating chamber, in contrast to pre-formed films that are not formed so closely to the surface that heat transfer is not optimal.

Preferably, the electrically insulating material coating comprises: ceramic and glass; ceramic and silicone; or glass and silicone. More preferably, the electrically insulating material coating comprises ceramic; glass; and silicone. In this way, the electrically insulating material coating provides significantly improved thermal conductivity compared to the use of typical electrically insulating films including polyetheretherketone (PEEK) or polyimide. In particular, the inclusion of glass and ceramics in silicone provides high temperature resistance (eg, a temperature rating of 482°C) and high thermal conductivity, while being able to form as a thin coating.

Preferably, the electrically insulating material coating consists of diamond-like carbon DLC.

Preferably, the heating assembly further comprises: a flexible electrically insulating film wrapping the heating chamber on the side of the heating element opposite the coating of electrically insulating material. In this way, the heating element is electrically isolated from other components within the aerosol-generating device. In one example, the heating element can be supported on a flexible electrically insulating film, and the heating element is attached to the electrically insulating material coating by wrapping the flexible electrically insulating film around the heating chamber, wherein the heating element is against the electrically insulating material coating Floor. In another example, the heating element can be supported on a carrier film, and the carrier film can be used to wrap the heating element with a coating of electrically insulating material. Once the heating element has been positioned, the carrier film can be removed and the flexible electrically insulating film can then be wrapped around the heating chamber.

Preferably, the flexible electrically insulating film is configured to secure the heating element against the coating of electrically insulating material.

Preferably, the flexible electrical insulating film comprises a heat shrinkable film. In this way, the heat shrink film ensures that the heating element remains in contact with the coating of electrically insulating material, while also maintaining the compact arrangement of the heating assembly.

In some embodiments, the heating element is attached to the coating of electrically insulating material using an adhesive.

In some embodiments, the heating assembly further comprises: a thin film heater including a heating element and a flexible backing film, the heating element being supported on the flexible backing film, wherein the thin film heater wraps the heating chamber, wherein The heating element bears against the coating of electrically insulating material.

Preferably, the coating of electrically insulating material surrounds the outer surface of the heating chamber and the heating element surrounds the heating chamber. In particular, a coating of electrically insulating material surrounds the peripheral outer surface of the heating chamber.

Preferably, the heating element comprises a resistive metal track.

Preferably, the thickness of the coating of electrically insulating material is between 0.8 microns and 20 microns, more preferably between 3 microns and 18 microns. For example, the thickness of the electrically insulating material coating may be 3 microns, 5 microns, 10 microns, 12.5 microns, 15 microns or 20 microns.

Preferably, the dielectric breakdown strength of the coating of electrically insulating material is at least 500 V/mm, more preferably at least 1000 V/mm.

According to a second aspect of the present invention, there is provided a method of making a heating assembly as claimed in any preceding claim, the method comprising: applying a coating of an electrically insulating material to an outer surface of a heating chamber using one of the following: Vapor deposition; painting; dipping; or spraying.

Preferably, the method further comprises: curing the coating of electrically insulating material at a temperature of at least 80°C. In particular, coatings of electrically insulating materials including ceramics, glass and silicone may be thermally cured after they are applied to the outer surface of the heating chamber. For example, a coating of electrical insulating material can be cured at 95°C for 15 minutes, then at 250°C for 15 minutes, and then at 540°C for 10 minutes.

In one embodiment, the method further comprises: supporting the heating element on a carrier film; wrapping the heating element in the heating chamber with the carrier film such that the heating element is positioned against the coating of electrically insulating material; removing the carrier film; A flexible electrically insulating film wraps the heating chamber such that the heating element is disposed between the flexible electrically insulating film and the coating of electrically insulating material.

In another embodiment, the method further comprises: supporting the heating element on a flexible electrically insulating film; wrapping the flexible electrically insulating film around the heating chamber such that the heating element is positioned against the coating of electrically insulating material.

Preferably, the method further comprises: heating the flexible electrically insulating film, which is a heat shrinkable film, such that the heating element is secured to the coating of electrically insulating material.

According to a third aspect of the present invention, there is provided an aerosol generating device comprising the heating element according to the first aspect.

Figure 1 shows an aerosol generating device 100 according to an embodiment of the present invention. Aerosol-generating device 100 is shown in an assembled configuration with internal components visible. Aerosol-generating device 100 is a heat-and-burn device, also referred to as a tobacco-vapor device, that includes a heating assembly 200 configured to receive, for example, a rod of aerosol-generating material (eg, tobacco), or the like Aerosol matrix. The heating assembly 200 is operable to heat but not burn the rod of aerosol-generating material to generate a vapor or aerosol for inhalation by a user. Of course, those skilled in the art will understand that the aerosol-generating device 100 depicted in Figure 1 is merely an exemplary aerosol-generating device in accordance with the present invention. Other types and configurations of tobacco-vapor products, vaporizers or electronic cigarettes may also be used as aerosol generating devices according to the present invention.

FIG. 2 shows a perspective view of a heating assembly 200 according to an embodiment of the present invention. Similarly, FIG. 3 shows a schematic cross-sectional view of heating element 200 , but heating element 200 further includes a flexible electrical insulating film 210 surrounding heating element 200 . The heating assembly 200 includes a heating chamber 202, also referred to as a thermally conductive housing, configured to retain an aerosol matrix (also referred to as a consumable) therein. In particular, the heating chamber 202 defines a cylindrical cavity in which the aerosol matrix rods can be positioned. The heating chamber 202 is tubular, eg cylindrical, and has openings 204 positioned at the longitudinal ends of the heating chamber 202 . In use, a user may insert the aerosol matrix into the heating chamber 202 through the opening 204 such that the aerosol matrix is positioned within the heating chamber 202 and engages the inner surface 201 of the heating chamber 202 . The length of the heating chamber 202 can be configured such that a portion of the aerosol matrix protrudes through the opening 204 in the heating chamber 202, ie, out of the heating assembly 200, and can be received in a user's mouth.

Heating chamber 202 comprises, and preferably is constructed of, metal so as to provide efficient heat transfer to the aerosol matrix through the sidewalls of heating chamber 202 while also ensuring that heating chamber 202 has sufficient structural stability and durability sex. Examples of suitable metals include steel or stainless steel.

The thickness of the tubular side walls of the heating chamber is preferably 0.1 mm or less, or more preferably between 0.07 mm and 0.09 mm. This allows for efficient heat transfer to the consumable through the sidewalls of the heating chamber 202 while maintaining sufficient structural stability. The tubular member has a closed end opposite the opening 204, wherein preferably the closed end has a thickness of 0.2 mm to 0.6 mm, which further increases the structural rigidity of the heating chamber. A method of making the heating chamber 202 is described in co-pending PCT/EP 2020/074147.

The heating chamber 202 may include a plurality of inwardly protruding elongated ridges, as shown in FIG. 5 . The elongated member may be formed by forcing the outer surface of the tubular member to provide a plurality of corresponding elongated protrusions extending lengthwise on the inner surface of the tubular member as the fluid is injected into the tubular member under pressure. shaped ridge.

Those skilled in the art will understand that the heating chamber 202 is not limited to being tubular. For example, the heating chamber 202 may be formed as a cuboidal, conical, hemispherical or other shaped cavity and configured to receive a complementary shaped aerosol matrix. Furthermore, in some embodiments, the heating chamber 202 may not completely surround the aerosol matrix, but only contact a limited area of the aerosol matrix.

A coating 206 of electrically insulating material (also referred to as an electrically insulating layer) surrounds the outer surface 203 of the heating chamber 202 . In particular, the electrically insulating material coating 206 is adjacent (ie, abuts, contacts) the peripheral outer surface 203 of the heating chamber 202 . That is, the electrically insulating material coating 206 is directly bonded to the outer surface 203 of the heating chamber 202 . In FIGS. 1 and 2 , the electrically insulating material coating 206 is depicted as extending along only a portion of the length of the outer surface 203 of the heating chamber 202 . However, those skilled in the art will appreciate that in other embodiments, the coating of electrically insulating material 206 may extend along the entire length of the heating chamber 202 . Furthermore, those skilled in the art will understand that the electrically insulating material coating 206 may only partially surround the outer surface of the heating chamber 202 .

The electrically insulating material coating 206 includes at least one of ceramic, glass, silicone, and carbon, or any combination thereof. Preferably, the electrically insulating material coating 206 includes (and optionally consists of) silicone, glass, and ceramic. This combination of components provides high electrical breakdown voltages, eg between 100 V/mm and 1000 V/mm, and exhibits high thermal conductivity compared to eg polyimides used in typical electrical insulating films . Additionally, thin coatings, such as 10 μm, may be used, which provide improved heat transfer to the aerosol matrix received within the heating chamber 202 . In contrast, polyimide has a thickness of about 25 microns. These features advantageously reduce the heating and cooling time of the heating chamber 202 and increase the energy efficiency of the heating assembly 200 . Advantageously, this coating material may also have a higher thermal stability than polyimide. For example, silicone glass is stable up to about 482°C, DLC is stable up to 300°C, silicone-modified alkyd resin is stable up to 450°C, and polyamide Imines are only stable up to 270°C. In other embodiments, the electrically insulating material coating 206 may comprise (and optionally consist of) diamond-like carbon (DLC) or a silicone modified alkyd.

The electrically insulating material coating 206 may be deposited using a variety of coating or deposition techniques, as will be discussed further with reference to FIG. 4 .

A heating element 208 including one or more heater tracks surrounds the coating 206 of electrically insulating material. In particular, the heating element 208 wraps the heating chamber 202 in a circumferential direction, for example, such that the heating element 208 is adjacent (ie, abuts, contacts) the coating 206 of electrically insulating material. The electrically insulating material coating 206 acts as a barrier separating the heating element 208 from the heating chamber 202 , thereby preventing the heating element 208 from coming into contact with the heating chamber 202 . Those skilled in the art will appreciate that the heating elements 208 may only partially surround the heating chamber 202 and/or one or more heating elements 208 may be arranged around the circumference of the heating chamber 202 .

The heating element 208 includes a heating material (eg, stainless steel, titanium, nickel, nichrome, nickel-based alloys, silver, etc.) suitable for converting electrical energy into heat. In the depicted embodiment, heating element 208 includes one or more resistive heater tracks. However, in other embodiments, the heating element 208 may be formed in alternate configurations, such as as a heating pad.

In use, heating element 208 may be powered from a power source (not depicted), such as a battery, such that the temperature of heating element 208 increases and thermal energy is transferred to heating chamber 202 through coating 206 of electrically insulating material. The aerosol matrix received within the heating chamber 202 is conductively heated by the heating chamber 202 to generate an aerosol for inhalation by the user.

Those skilled in the art will understand that the heating chamber 202 is not a resistive heater and therefore should not receive electrical current. Accordingly, the electrically insulating material coating 206 advantageously prevents short circuits from occurring between the heating element 208 and the heating chamber 202 while allowing efficient heat transfer from the heating element 208 to the heating chamber 202 . That is, the electrically insulating material coating 206 separates the heating element 208 from the heating chamber 202 and ensures that electrical current does not flow from the heating element 208 to the heating chamber 202 . This eliminates the need for an additional layer of polyimide or PEEK, which is typically wrapped between the heating chamber 202 and the heating element 208 in conventional aerosol generating devices. Furthermore, those skilled in the art will appreciate that the efficiency of heat transfer from heating element 208 to heating chamber 202 may be improved due to the low thickness of electrically insulating material coating 206 .

As shown in FIG. 3 , a layer of electrically insulating film 210 wraps heating chamber 202 on the opposite side of heating element 208 from coating 206 of electrically insulating material. That is, the heating element 208 is interposed between the electrically insulating material coating 206 and the electrically insulating film 210 . The electrically insulating film 210 comprises preferably a flexible material with high dielectric properties and low thermal mass, such as polyimide, polyetheretherketone (PEEK) or polytetrafluoroethylene (PTFE).

In some embodiments, the electrically insulating film 210 may be a heat shrink film such that the heating element 208 is secured against the electrically insulating material coating 206 . In other words, the electrically insulating film 210 surrounding the exterior of the heating assembly 200 reinforces the heating assembly 200 and ensures that the heating element 208 remains in contact with the electrically insulating material coating 206 . Additionally or alternatively, the heating element 208 may be secured to the electrically insulating material coating 206 using an adhesive.

In FIG. 3 , the electrically insulating film 210 is shown completely encapsulating the heating element 208 and the electrically insulating material coating 206 . That is, the electrically insulating film 210 extends beyond the extent of the heating element 208 and up to the longitudinal edge of the coating of electrically insulating material. However, it will be appreciated that the size and arrangement of the electrically insulating film 210 may vary.

In the depicted embodiment, heating element 208 is a separate heating element attached to coating 206 of electrically insulating material. However, in alternative embodiments, the heating element 208 may be included within a thin film heater (not shown), wherein the thin film heater includes a flexible backing film on which the heating element 208 is disposed. For example, the heating element can be adhered to the flexible backing film, eg, by a silicone adhesive. In this case, the thin film heater may wrap the heating chamber 200 in a circumferential direction such that the heating element 208 is adjacent to the coating 206 of electrically insulating material. The flexible backing film is located on the opposite side of the heating element 208 from the electrically insulating material coating 206 , ie the heating element 208 is mounted to the inner surface of the flexible backing film opposite the heating chamber 202 .

FIG. 4 shows a flowchart of a method 300 of fabricating a heating chamber in accordance with an embodiment of the present invention.

The method 300 begins at step 302 in which a heating chamber 202 is provided having an opening 204 for receiving an aerosol matrix within the heating chamber 202 . The heating chamber 202 may be fabricated according to the method described in PCT/EP 2020/074147 as mentioned previously. At step 304 , a coating 206 of electrically insulating material is applied to the outer surface 203 of the heating chamber 202 . That is, the electrically insulating material coating 206 is bonded to the outer surface of the heating chamber 202 such that the coating at least partially surrounds, preferably surrounds, the heating chamber 202 in the circumferential direction. Coatings can be applied using a variety of coating processes and techniques, such as vapor deposition, chemical and electrochemical techniques, spraying, dipping, or painting. For example, the electrically insulating material coating 206 may be applied using plasma spray, wire arc spray, cathodic arc deposition, sputter deposition, or ion beam deposition. These processes and techniques can be selected according to the coating material.

Optionally, at step 306, the electrical insulating material coating 206 is cured in one or more curing stages, preferably at a temperature above 80°C. In one example, the electrical insulating material coating can be cured at 95°C for 15 minutes, then at 250°C for 15 minutes, and finally at 250°C for 10 minutes. This particular curing process is particularly suitable for layers 206 of electrically insulating material comprising silicone, preferably silicone, glass and ceramic. Those skilled in the art will understand that the term "curing", also known as high temperature curing or thermal curing, refers to a method of hardening or toughening a polymer such as silicone by promoting cross-linking of the polymer chains. The curing process increases the resistance of the electrically insulating material coating 206 to corrosion and degradation.

At step 308 , the heating element 208 is attached to the coating 206 of electrically insulating material. In particular, the heating element 208 wraps the portion of the heating chamber 202 covered by the electrically insulating material coating 206 such that the heating element 208 at least partially surrounds the heating chamber 202, preferably surrounds the heating chamber 202, but due to the electrical insulation The insulating material coating 206 provides a physical barrier from contacting the heating chamber 202 .

In one embodiment, the heating element 208 may wrap the heating chamber 202 with a carrier film 212, as shown in FIG. 5 . That is, the heating element 208 is supported on the surface of the carrier film 212 , and the method 300 further includes wrapping the carrier film 212 around the heating chamber 202 in a circumferential direction such that the heating element 208 abuts the electrically insulating material coating 206 . Once the heating element 208 is properly positioned, the carrier film 212 can be removed.

In another embodiment, the heating element 208 may be included within a thin film heater, wherein the thin film heater includes the heating element 208 and a flexible backing film on which the heating element 208 is supported. In this case, method 300 includes wrapping the thin film heater around heating chamber 202 with heating element 208 against coating 206 of electrically insulating material.

At step 310, a flexible electrically insulating film 210 is wrapped around the heating chamber 202. The flexible electrically insulating film 210 encapsulates the heating element 208 such that the heating element 208 is interposed between the flexible electrically insulating film 210 and the coating 206 of electrically insulating material.

In one embodiment, heating element 208 may be supported on flexible electrically insulating film 210 prior to attachment to coating 206 of electrically insulating material. In this case, the heating element 206 is wrapped around the heating chamber 202 using a flexible electrically insulating film 210, ie, steps 308 and 310 occur simultaneously.

In some embodiments, the flexible electrically insulating film 210 may be a heat shrinkable film. In this case, method 300 further includes applying heat to flexible electrically insulating film 210 such that flexible electrically insulating film 210 shrinks around heating element 208 and heating element 208 is secured against coating 206 of electrically insulating material.

none.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: [FIG. 1] is an exemplary aerosol generating device according to an embodiment of the present invention; [FIG. 2] is a perspective view of a heating element according to an embodiment of the invention; [Fig. 3] is a schematic cross-sectional view of the heating element of Fig. 2, the heating element further comprises a flexible electrical insulating film; [ FIG. 4 ] is a flowchart showing the steps of a method for manufacturing a heating element according to an embodiment of the present invention; and [FIG. 5] It is a perspective view of the heating assembly of FIG. 2, showing the application of the heating element using the carrier film.

100: Aerosol Generation Device

200: Heating components

Claims (15)

A heating assembly for an aerosol generating device, the heating assembly comprising: a metal tubular heating chamber including an opening for receiving the aerosol matrix; a coating of electrically insulating material at least partially surrounding the outer surface of the heating chamber, wherein the coating of electrically insulating material comprises one or more of the following: ceramic; glass; silicone; and carbon; as well as A heating element at least partially surrounding the heating chamber and disposed against the coating of electrically insulating material, wherein the coating of electrically insulating material prevents any contact between the heating element and the heating chamber. The heating element of claim 1, wherein the electrically insulating material coating comprises: ceramics and glass; ceramics and silicones; or Glass and silicone. The heating element of claim 2, wherein the electrically insulating material coating comprises ceramic; glass; and silicone. The heating element of claim 1, wherein the electrically insulating material coating is composed of diamond-like carbon DLC. The heating assembly of any preceding claim, further comprising: A flexible electrically insulating film wrapping the heating chamber on the side of the heating element opposite the coating of electrically insulating material. The heating assembly of claim 5, wherein the flexible electrically insulating film is configured to secure the heating element against the coating of electrically insulating material. The heating element of claim 6, wherein the flexible electrical insulating film comprises a heat shrinkable film. A heating assembly as claimed in any preceding claim, wherein the heating element is attached to the coating of electrically insulating material using an adhesive. The heating assembly of any preceding claim, further comprising: A thin film heater comprising the heating element and a flexible backing film, the heating element supported on the flexible backing film, wherein the thin film heater wraps the heating chamber, wherein the heating element abuts the electrical Insulating material coating. A heating assembly as claimed in any preceding claim, wherein the coating of electrically insulating material surrounds an outer surface of the heating chamber, and wherein the heating element surrounds the heating chamber. A heating assembly as claimed in any preceding claim, wherein the heating element comprises a resistive metal track. A heating element as claimed in any preceding claim, wherein the thickness of the coating of electrically insulating material is between 0.8 microns and 20 microns. A heating element as claimed in any preceding claim, wherein the dielectric breakdown strength of the coating of electrically insulating material is at least 100 V/mm, preferably at least 1000 V/mm. A method of making a heating element as claimed in any preceding claim, the method comprising: The electrically insulating material coating is applied to the outer surface of the heating chamber using one of the following: vapor deposition; painting; dipping; or spraying. The method of claim 14, further comprising: The electrically insulating material coating is cured at a temperature of at least 80°C.

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