Heater assembly with molded porous body

Abstract

A heater assembly (100) for an aerosol generating system (600), comprising: a heating element (110) for vaporizing a liquid aerosol forming substrate; and a porous body (120) for transporting the liquid aerosol forming substrate to the heating element (110), wherein the porous body (120) has a liquid absorption surface (130) and a heating surface (140), the heating element (110) is located on the heating surface (140) of the porous body (120), the liquid absorption surface (130) of the porous body (120) has an area different from the area of ​​the heating surface (140) of the porous body (120), and the porous body (120) includes a porous ceramic body or a porous glass body.

Description

Technical Field

[0001] The present disclosure relates to a heater assembly. In particular, and without limitation, the present disclosure relates to a heater assembly for a handheld electrically operated aerosol generation system for heating an aerosol forming substrate to generate an aerosol.

Background Art

[0002] Aerosol generation systems that heat a liquid aerosol forming substrate to generate an aerosol for delivery to a user are generally known in the prior art. These systems typically comprise an aerosol generator and a replaceable cartridge. The cartridge typically contains a liquid aerosol forming substrate that can release a volatile compound when heated. The cartridge typically also includes a heater for heating the liquid aerosol forming substrate. In known aerosol generation systems, the heater comprises a resistive heating element wound around a wick that supplies the liquid aerosol forming substrate to the heating element. The aerosol generator or cartridge also typically includes a mouthpiece. When the user inhales through the mouthpiece, an electric current flows through the heating element, heating the heating element by resistive heating or Joule heating, and as a result, heating the liquid aerosol forming substrate supplied by the wick. This causes volatile compounds to be released from the liquid aerosol forming substrate and, upon cooling, an aerosol is formed. The aerosol is then inhaled into the user's mouth through the mouthpiece.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Such known aerosol generating systems have many drawbacks. For example, it is difficult to manufacture them while maintaining consistent manufacturing tolerances, which can lead to inconsistent vapor generation and flavor development. Inconsistent manufacturing tolerances can also affect heat conduction from the heating element to the wick, reducing the energy efficiency of such devices. A further problem faced by such well-known aerosol generating systems is "dry heating" or "dry puffing," which occurs when the heating element is heated without a sufficient supply of liquid aerosol-forming substrate. This can occur, for example, when the user consumes all the liquid aerosol-forming substrate in a cartridge and the cartridge becomes depleted and needs to be replaced. During operation, it is preferable to maintain a supply of liquid aerosol-forming substrate to the heating element so that it remains moist, in order to ensure that a satisfactory aerosol is generated when the user inhales. Dry heating can lead to overheating of the heating element and potentially to thermal decomposition of the liquid aerosol-forming substrate, which may result in undesirable byproducts and, furthermore, unsatisfactory aerosol generation. Allowing the aerosol generation system to continue operating even when the liquid aerosol-forming substrate is not supplied to the heat-generating element could potentially degrade the quality of the user experience.

[0004] In an attempt to solve some of the aforementioned problems, a heater assembly design has been proposed that utilizes an atomizer core consisting of a heating element, electrical contacts, and a porous atomizer body. The liquid aerosol-forming substrate is supplied from the cartridge's storage section to the heating element through pores present within the atomizer body.

[0005] It is desirable to provide a heater assembly that can offer improved aerosol throughput. [Brief explanation of the drawing]

[0006] [Figure 1]Figure 1 schematically shows a perspective view of a first embodiment of the heater assembly according to the present disclosure. [Figure 2] Figure 2 schematically shows a side view of the first embodiment of the heater assembly shown in Figure 1. [Figure 3] Figure 3 schematically shows a perspective view of a second embodiment of the heater assembly according to the present disclosure. [Figure 4] Figure 4 schematically shows a perspective view of a third embodiment of the heater assembly according to the present disclosure. [Figure 5] Figure 5 schematically shows a perspective view of a fourth embodiment of the heater assembly according to the present disclosure. [Figure 6] Figure 6 schematically shows a side view of the fourth embodiment of the heater assembly shown in Figure 5. [Figure 7] Figure 7 schematically shows a perspective view of a fifth embodiment of the heater assembly according to the present disclosure. [Figure 8] Figure 8 schematically shows a perspective view of a sixth embodiment of the heater assembly according to the present disclosure. [Figure 9] Figures 9(a), 9(b), and 9(c) show schematic embodiments of the heating element track according to the present disclosure. [Figure 10] Figures 10(a) and 10(b) show schematic examples of current flow around the corners of the heating element track according to the present disclosure. [Figure 11] Figure 11 schematically shows a cross-sectional view of the aerosol generation system according to this disclosure. [Modes for carrying out the invention]

[0007] According to certain embodiments of the present disclosure, a heater assembly for an aerosol generating system is provided. The heater assembly may comprise a heating element for vaporizing a liquid aerosol-forming substrate. The heater assembly may comprise a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body may have a liquid-absorbing surface. The porous body may have a heating surface. The heating element may be located on the heating surface of the porous body. The liquid-absorbing surface of the porous body may have a different area from the heating surface of the porous body. The porous body may include a porous ceramic body or a porous glass body.

[0008] According to embodiments of the present disclosure, a heater assembly for an aerosol generating system is provided, comprising: a heating element for vaporizing a liquid aerosol forming substrate; and a porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface, the heating element is located on the heating surface of the porous body, the liquid absorption surface of the porous body has an area different from the area of ​​the heating surface of the porous body, and the porous body includes a porous ceramic body or a porous glass body.

[0009] Heater assemblies with a heating surface having the same area as the liquid absorption surface can be inefficient because the heat generated by the heater is not used to vaporize the aerosol-forming substrate. Inefficient heater assemblies reduce aerosol throughput.

[0010] Advantageously, providing a porous material with different areas for the heating surface and the liquid absorption surface can improve the throughput of aerosols that may be generated by the heater assembly compared to a heater assembly where the heating surface has the same area as the liquid absorption surface.

[0011] For example, in a heater assembly where the heating surface area of ​​the porous material is smaller than the liquid-absorbing surface area of ​​the porous material, the heat flow conducted from the heating element to the liquid-absorbing surface and then to the liquid storage area can be reduced. A relatively small heating surface provides a small heat transfer area for heat to be transferred by conduction from the heating element to the porous material and then to the liquid-absorbing surface.

[0012] Since much of the thermal energy provided by the heating element can be used to vaporize the aerosol-forming substrate, reducing heat loss from the heating element to the porous bulk can consequently increase heating efficiency. As a result, porous materials with a shape in which the heated surface has a smaller area than the liquid-absorbing surface can increase the throughput of aerosols generated by the heater assembly.

[0013] For example, in a heater assembly where the area of ​​the porous liquid-absorbing surface is smaller than the area of ​​the porous heating surface, the smaller the area of ​​the liquid-absorbing surface, the less heat can flow from the heating element to the liquid-absorbing surface through the aerosol-forming substrate via heat conduction.

[0014] Since much of the thermal energy provided by the heating element can be used to vaporize the liquid aerosol-forming substrate, reducing the heat flow from the heated surface to the liquid-absorbing surface can consequently increase heating efficiency. As a result, porous materials having a shape in which the liquid-absorbing surface has a smaller area than the heated surface may provide improved heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0015] Increased heating efficiency may reduce power consumption during use of the heater assembly.

[0016] As used herein, the term "aerosol generator" refers to a device that interacts with a liquid aerosol-forming substrate in order to generate an aerosol.

[0017] As used herein, the terms “cartridge” and “aerosol generating cartridge” refer to components that interact with a liquid aerosol generating apparatus for generating an aerosol. An aerosol generating cartridge contains, or is configured to contain, a liquid aerosol-forming substrate.

[0018] As used herein, the term "liquid aerosol-forming substrate" relates to a liquid substrate having the ability to release volatile compounds capable of forming an aerosol. Such volatile compounds can be released by heating the liquid aerosol-forming substrate.

[0019] As used herein, "heating element" refers to a component that transfers thermal energy to the liquid aerosol-forming substrate. It is understood that the heating element can be disposed directly on the porous body.

[0020] As used herein, the term "porous body" refers to a component having a plurality of pores, at least some of which are interconnected. The porous body is configured to contain liquid within the plurality of pores.

[0021] <0000As used herein, the term "longitudinal axis" is used to describe an axis that extends between the liquid absorption surface of the porous body and the heating surface of the porous body.

[0022] As used herein, the term "longitudinal direction" is used to describe the direction between the liquid absorption surface of the porous body and the heating surface of the porous body. During use of the heater assembly, the liquid aerosol-forming substrate is drawn from the liquid absorption surface of the porous body to the heating surface of the porous body substantially along the longitudinal direction.

[0023] As used herein, the term "thickness" is used to describe the maximum dimension in the longitudinal direction of the heater assembly, a component of the heater assembly, or a part of the heater assembly. The thickness of the heater assembly, a component of the heater assembly, or a part of the heater assembly may also be referred to as the height of the heater assembly, a component of the heater assembly, or a part of the heater assembly, respectively.

[0024] <0000As used herein, the term “angle between mean vapor discharge direction and mean airflow direction” refers to the angle between the direction of vapor movement from a heater assembly and the airflow within the airflow path. For example, an angle of zero degrees means that the airflow and vapor discharge are moving in the same direction, while an angle of 180 degrees means that the directions of airflow and vapor discharge are directly opposite each other.

[0025] As used herein, the term “thermal insulation” refers to a property that reduces or limits heat transfer. A more thermally insulating component transfers less heat than a less thermally insulating component, via conduction, convection, or radiation.

[0026] The heating element may be located within the porous body.

[0027] The heating element may extend over most of the heated surface of the porous body. The heating element may extend over substantially all of the heated surface of the porous body.

[0028] The heating element may be a fluid-permeable heating element. The liquid can pass through the fluid path of the porous ceramic body from the liquid-absorbing surface to the heated surface.

[0029] The heating element may comprise a porous layer of conductive material. Advantageously, a heating element comprising a porous layer of conductive material allows for resistance heating and also allows electric current to flow through the heating element, enabling vapor to move through the pores within its porous structure. Therefore, vapor release occurs through the porous heating element. This avoids the accumulation of vapor pressure beneath the heating element and high-speed vapor release at the sides of the heating element. The inventors found that this arrangement generates consistent vapor across the heating element, resulting in a low vapor release velocity of approximately 0.1 meters / second. Such a low vapor release velocity means that the vapor is easily carried by an airflow that reduces vapor collisions on the inner walls of the aerosol generating system.

[0030] The heating element may be bonded to the heated surface of the porous body.

[0031] The heating element may be electrically connected to an electrical contact. The heating element may be configured to heat a liquid aerosol-forming substrate as a potential difference is applied to the electrical contact. The heating element may have one or more curved or meandering shapes. The heating element may include an electrically resistant heating element. The heating element may be made from any suitable conductive material. Suitable materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilide), carbon, graphite, metals, alloys, and composite materials made of ceramic and metallic materials. Such composite materials may include doped or undoped ceramics. An example of a suitable doped ceramic is doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Suitable alloys include stainless steel, constantan, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal®, iron-aluminum alloys, and iron-manganese-aluminum alloys. Timetal® is a registered trademark of Titanium Metals Corporation. The heating element may be made from stainless steel, such as 300 series stainless steels like AISI 304, 316, 304L, and 316L. The electric heating element may comprise one or more of NiCr and TiZr.

[0032] Additionally, the heating element may include combinations of the materials described above. Combinations of materials may be used to improve the control of the resistance of the heating element. For example, a material with high resistivity may be combined with a material with low resistivity. This may be advantageous if one of the materials is more beneficial in terms of other respects, such as price, machinability, or other physical and chemical parameters. Advantageously, heating at high resistance allows for more efficient use of battery energy.

[0033] The heating element and the porous body may be formed integrally.

[0034] The heating element and the porous body may be molded as a single monolithic piece.

[0035] Advantageously, this can help simplify the manufacturing of heater assemblies by reducing manufacturing time and providing a more cost-effective solution. This is also advantageous in that it can create a tight mechanical connection between the heating element and the porous body.

[0036] The heating element may be a doped portion of a porous material.

[0037] The porous material may be doped such that the portion of the porous material acting as a heat-generating element is conductive. Doping the porous material may be advantageous in that it avoids changes in the porosity of the porous material. This may be preferable to other known techniques for forming heat-generating elements, including depositing the heat-generating element by thin-film or thick-film techniques that can reduce the properties of the porous material, particularly the porosity. The doped portion may be 5 to 100 micrometers thick. The thickness of the doped portion may be increased if the cross-sectional area of ​​the heat-generating element is small or if the required heating resistance is high. The dopant used to dope the porous material may be an n-type dopant or a p-type dopant. The dopant may be, but is not limited to, nitrogen, phosphorus, aluminum, or boron. The interface between the heat-generating element and the porous material may include a portion of the partially doped porous material.

[0038] The heating element may be located on the heated surface of the porous body and may also be bonded to the heated surface of the porous body.

[0039] The porous material may be substantially incompressible.

[0040] The porous material may have a porosity of 30% to 70%. The porous material may also be an open-cell porous material.

[0041] Porous materials may have been manufactured by sintering. Porous materials may have been manufactured by directly sintering ceramic powder to form a porous material with pores between interconnected powder particles. Porous materials may have been manufactured by using sacrificial material in ceramic powder, where the sacrificial material is used as a spacer to form pores. The sacrificial material may have burned out during sintering.

[0042] The porous body may have a trapezoidal prism shape. The porous body may have a pyramidal shape. The porous body may have a truncated pyramidal shape. The porous body may have a conical shape. The porous body may have a truncated conical shape. The shape of the porous body can be adapted to the chamber in the cartridge. The shape of the porous body can be adapted to the shape of the heating element.

[0043] The porous material may have a first average pore diameter at the liquid-absorbing surface and a second average pore diameter at the heating surface. The first average pore diameter may be substantially the same as the second average pore diameter.

[0044] The porous material may be a porous ceramic material. The porous material may be a porous glass material.

[0045] The liquid absorption surface may face the heating surface.

[0046] The liquid absorption surface and the heating surface may be substantially parallel to each other.

[0047] The liquid-absorbing surface of the porous material may be substantially flat.

[0048] The heating surface of the porous material may be substantially flat. The heating surface may be the porous outer surface of the porous material. The heating element may extend at least partially into the pores of the porous material adjacent to the heating surface.

[0049] The heating surface of the porous body on which the heating element is located may have substantially the same area as the heating element.

[0050] The heating surface may have a size less than or equal to the size of the heating element.

[0051] The heating surface may have an area less than or equal to the area of ​​the heating element.

[0052] The area of ​​the heated surface of the porous material may be smaller than the area of ​​the liquid-absorbing surface of the porous material. The area of ​​the liquid-absorbing surface of the porous material may be larger than the area of ​​the heated surface of the porous material.

[0053] Advantageously, if the porous material has a shape such that the heated surface has a smaller area than the liquid-absorbing surface, the heat flow conducted from the heating element to the liquid-absorbing surface and then to the liquid storage portion can be reduced. The relatively small heated surface provides a small heat transfer area for heat to be transferred by conduction from the heating element to the porous material and then to the liquid-absorbing surface.

[0054] Since much of the thermal energy provided by the heating element can be used to vaporize the aerosol-forming substrate, reducing heat loss from the heating element to the porous bulk can consequently increase heating efficiency. As a result, porous materials with a shape in which the heated surface has a smaller area than the liquid-absorbing surface can increase the throughput of aerosols generated by the heater assembly.

[0055] Advantageously, a porous body having a shape such that the heating surface has a smaller area than the liquid absorption surface can reduce the area of ​​the heating surface that is not sufficiently close to the heating element, allowing the aerosol-forming substrate to be transported to the heating surface and vaporized. In other words, the size and shape of the heating surface may more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be transported from the liquid absorption surface to the area of ​​the heating surface closer to the heating element, thereby allowing more liquid aerosol-forming substrate to vaporize on the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the throughput of aerosols generated by the heater assembly. Furthermore, this arrangement can maximize the power density on the heating surface, which also improves heating efficiency.

[0056] Advantageously, a liquid absorption surface having a larger surface area than the heating surface may allow the liquid absorption surface to receive a larger volume of liquid aerosol substrate from the liquid storage portion. Because the heating surface has a relatively small surface area, the flow rate of liquid aerosol-forming substrate to the heating element may be higher than that in a typical heater assembly as the liquid aerosol-forming substrate is transported through the porous material toward the heating surface. A higher flow rate of liquid aerosol-forming substrate in the heating element may increase the throughput of aerosols generated by the heater assembly.

[0057] The heating surface may have an area of ​​at least 0.5 square millimeters. The heating surface may have an area of ​​at least 1 square millimeter. The heating surface may have an area of ​​at least 2 square millimeters. The heating surface may have an area of ​​at least 3 square millimeters. The heating surface may have an area of ​​at least 5 square millimeters. The heating surface may have an area of ​​at least 10 square millimeters. The heating surface may have an area of ​​at least 15 square millimeters. The heating surface may have an area of ​​at least 20 square millimeters. The heating surface may have an area of ​​at least 25 square millimeters.

[0058] The heating surface may have an area of ​​40 square millimeters or less. The heating surface may have an area of ​​30 square millimeters or less. The heating surface may have an area of ​​25 square millimeters or less. The heating surface may have an area of ​​20 square millimeters or less. The heating surface may have an area of ​​15 square millimeters or less. The heating surface may have an area of ​​10 square millimeters or less. The heating surface may have an area of ​​5 square millimeters or less.

[0059] The heating surface may have an area of ​​0.5 square millimeters to 40 square millimeters. The heating surface may have an area of ​​0.5 square millimeters to 30 square millimeters. The heating surface may have an area of ​​1 square millimeter to 30 square millimeters. The heating surface may have an area of ​​2 square millimeters to 25 square millimeters. The heating surface may have an area of ​​3 square millimeters to 20 square millimeters. The heating surface may have an area of ​​5 square millimeters to 15 square millimeters.

[0060] The liquid-absorbing surface may have an area of ​​at least 1 square millimeter. The liquid-absorbing surface may have an area of ​​at least 2 square millimeters. The liquid-absorbing surface may have an area of ​​at least 3 square millimeters. The liquid-absorbing surface may have an area of ​​at least 5 square millimeters. The liquid-absorbing surface may have an area of ​​at least 10 square millimeters. The liquid-absorbing surface may have an area of ​​at least 20 square millimeters. The liquid-absorbing surface may have an area of ​​at least 30 square millimeters. The liquid-absorbing surface may have an area of ​​at least 40 square millimeters. The liquid-absorbing surface may have an area of ​​at least 50 square millimeters. The liquid-absorbing surface may have an area of ​​at least 60 square millimeters. The liquid-absorbing surface may have an area of ​​at least 70 square millimeters. The liquid-absorbing surface may have an area of ​​at least 80 square millimeters. The liquid-absorbing surface may have an area of ​​at least 90 square millimeters.

[0061] The liquid-absorbing surface may have an area of ​​100 square millimeters or less. The liquid-absorbing surface may have an area of ​​90 square millimeters or less. The liquid-absorbing surface may have an area of ​​80 square millimeters or less. The liquid-absorbing surface may have an area of ​​70 square millimeters or less. The liquid-absorbing surface may have an area of ​​60 square millimeters or less. The liquid-absorbing surface may have an area of ​​50 square millimeters or less. The liquid-absorbing surface may have an area of ​​40 square millimeters or less. The liquid-absorbing surface may have an area of ​​30 square millimeters or less. The liquid-absorbing surface may have an area of ​​20 square millimeters or less. The liquid-absorbing surface may have an area of ​​10 square millimeters or less.

[0062] The liquid-absorbing surface may have an area of ​​1 square millimeter to 100 square millimeters. The liquid-absorbing surface may have an area of ​​2 square millimeters to 100 square millimeters. The liquid-absorbing surface may have an area of ​​2 square millimeters to 90 square millimeters. The liquid-absorbing surface may have an area of ​​3 square millimeters to 80 square millimeters. The liquid-absorbing surface may have an area of ​​5 square millimeters to 70 square millimeters. The liquid-absorbing surface may have an area of ​​10 square millimeters to 60 square millimeters. The liquid-absorbing surface may have an area of ​​20 square millimeters to 50 square millimeters. The liquid-absorbing surface may have an area of ​​30 square millimeters to 40 square millimeters.

[0063] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.9 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.8 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.7 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.6 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.5 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.4 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.3 or less. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.2 or less.

[0064] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.1. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.2. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.3. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.4. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.5. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.6. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.7. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be at least 0.8.

[0065] The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.1 to 0.9. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.2 to 0.8. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.3 to 0.7. The ratio of the area of ​​the heated surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material may be 0.4 to 0.6.

[0066] The heated surface of the porous material may have a width different from the width of the liquid-absorbing surface of the porous material. The heated surface of the porous material may have a width different from the width of the liquid-absorbing surface of the porous material in the same transverse direction.

[0067] The heated surface of the porous material may have a width smaller than the width of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a width larger than the width of the heated surface of the porous material.

[0068] The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.9 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.8 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.7 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.6 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.5 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.4 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.3 or less. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.2 or less.

[0069] The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.1. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.2. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.3. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.4. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.5. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.6. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.7. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be at least 0.8.

[0070] The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.1 to 0.9. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.2 to 0.8. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.3 to 0.7. The ratio of the width of the heated surface of the porous material to the width of the liquid-absorbing surface of the porous material may be 0.4 to 0.6.

[0071] The heated surface of the porous material may have a length shorter than the length of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a length longer than the length of the heated surface of the porous material.

[0072] The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.9 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.8 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.7 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.6 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.5 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.4 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.3 or less. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.2 or less.

[0073] The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.1. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.2. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.3. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.4. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.5. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.6. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.7. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be at least 0.8.

[0074] The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.1 to 0.9. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.2 to 0.8. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.3 to 0.7. The ratio of the length of the heated surface of the porous material to the length of the liquid-absorbing surface of the porous material may be 0.4 to 0.6.

[0075] The heated surface of the porous material may have a width or length smaller than the width of the liquid-absorbing surface of the porous material.

[0076] The heated surface of the porous material may have a smaller perimeter than the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a larger perimeter than the heated surface of the porous material.

[0077] The heating surface of the porous material may have a diameter smaller than the diameter of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a diameter larger than the diameter of the heating surface of the porous material.

[0078] The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.9 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.8 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.7 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.6 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.5 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.4 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.3 or less. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.2 or less.

[0079] The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.1. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.2. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.3. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.4. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.5. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.6. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.7. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be at least 0.8.

[0080] The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.1 to 0.9. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.2 to 0.8. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.3 to 0.7. The ratio of the diameter of the heated surface of the porous material to the diameter of the liquid-absorbing surface of the porous material may be 0.4 to 0.6.

[0081] The heated surface of the porous material may have a smaller perimeter than the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a larger perimeter than the heated surface of the porous material.

[0082] The porous material may include a shape that tapers from the liquid-absorbing surface toward the heating surface.

[0083] The area of ​​the heated surface of the porous material may be larger than the area of ​​the liquid-absorbing surface of the porous material. The area of ​​the liquid-absorbing surface of the porous material may be smaller than the area of ​​the heated surface of the porous material.

[0084] Advantageously, if the porous material has a shape such that the liquid absorption surface has a smaller area than the heating surface, the smaller area of ​​the liquid absorption surface can lead to a reduction in heat flow from the heating element to the liquid absorption surface through the aerosol-forming substrate via heat conduction. Since much of the thermal energy provided by the heating element can be used to vaporize the liquid aerosol-forming substrate, reducing the heat flow from the heating surface to the liquid absorption surface can consequently increase thermal efficiency. As a result, a porous material having a shape such that the liquid absorption surface has a smaller area than the heating surface may offer improved heating efficiency, which can increase the throughput of aerosols generated by the heater assembly.

[0085] Advantageously, a porous body having a shape such that the liquid absorption surface has a smaller area than the heating surface can reduce the area of ​​the heating surface that is not sufficiently close to the heating element, allowing the aerosol-forming substrate to be transported to the heating surface and vaporized. In other words, the size and shape of the heating surface may more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be transported from the liquid absorption surface to the area of ​​the heating surface closer to the heating element, thereby allowing more liquid aerosol-forming substrate to vaporize on the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the aerosol throughput generated by the heater assembly.

[0086] The heating surface may have an area of ​​at least 1 square millimeter. The heating surface may have an area of ​​at least 2 square millimeters. The heating surface may have an area of ​​at least 3 square millimeters. The heating surface may have an area of ​​at least 5 square millimeters. The heating surface may have an area of ​​at least 10 square millimeters. The heating surface may have an area of ​​at least 20 square millimeters. The heating surface may have an area of ​​at least 30 square millimeters. The heating surface may have an area of ​​at least 40 square millimeters. The heating surface may have an area of ​​at least 50 square millimeters. The heating surface may have an area of ​​at least 60 square millimeters. The heating surface may have an area of ​​at least 70 square millimeters. The heating surface may have an area of ​​at least 80 square millimeters. The heating surface may have an area of ​​at least 90 square millimeters.

[0087] The heating surface may have an area of ​​100 square millimeters or less. The heating surface may have an area of ​​90 square millimeters or less. The heating surface may have an area of ​​80 square millimeters or less. The heating surface may have an area of ​​70 square millimeters or less. The heating surface may have an area of ​​60 square millimeters or less. The heating surface may have an area of ​​50 square millimeters or less. The heating surface may have an area of ​​40 square millimeters or less. The heating surface may have an area of ​​30 square millimeters or less. The heating surface may have an area of ​​20 square millimeters or less. The heating surface may have an area of ​​10 square millimeters or less.

[0088] The heating surface may have an area of ​​1 square millimeter to 100 square millimeters. The heating surface may have an area of ​​2 square millimeters to 100 square millimeters. The heating surface may have an area of ​​2 square millimeters to 90 square millimeters. The heating surface may have an area of ​​3 square millimeters to 80 square millimeters. The heating surface may have an area of ​​5 square millimeters to 70 square millimeters. The heating surface may have an area of ​​10 square millimeters to 60 square millimeters. The heating surface may have an area of ​​20 square millimeters to 50 square millimeters. The heating surface may have an area of ​​30 square millimeters to 40 square millimeters.

[0089] The liquid-absorbing surface may have an area of ​​at least 0.5 square millimeters. The liquid-absorbing surface may have an area of ​​at least 1 square millimeter. The liquid-absorbing surface may have an area of ​​at least 2 square millimeters. The liquid-absorbing surface may have an area of ​​at least 3 square millimeters. The liquid-absorbing surface may have an area of ​​at least 5 square millimeters. The liquid-absorbing surface may have an area of ​​at least 10 square millimeters. The liquid-absorbing surface may have an area of ​​at least 15 square millimeters. The liquid-absorbing surface may have an area of ​​at least 20 square millimeters. The liquid-absorbing surface may have an area of ​​at least 25 square millimeters.

[0090] The liquid-absorbing surface may have an area of ​​40 square millimeters or less. The liquid-absorbing surface may have an area of ​​30 square millimeters or less. The liquid-absorbing surface may have an area of ​​25 square millimeters or less. The liquid-absorbing surface may have an area of ​​20 square millimeters or less. The liquid-absorbing surface may have an area of ​​15 square millimeters or less. The liquid-absorbing surface may have an area of ​​10 square millimeters or less. The liquid-absorbing surface may have an area of ​​5 square millimeters or less.

[0091] The liquid-absorbing surface may have an area of ​​0.5 square millimeters to 40 square millimeters. The liquid-absorbing surface may have an area of ​​0.5 square millimeters to 30 square millimeters. The liquid-absorbing surface may have an area of ​​1 square millimeter to 30 square millimeters. The liquid-absorbing surface may have an area of ​​2 square millimeters to 25 square millimeters. The liquid-absorbing surface may have an area of ​​3 square millimeters to 20 square millimeters. The liquid-absorbing surface may have an area of ​​5 square millimeters to 15 square millimeters.

[0092] The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.9 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.8 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.7 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.6 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.5 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.4 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.3 or less. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.2 or less.

[0093] The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.1. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.2. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.3. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.4. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.5. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.6. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.7. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be at least 0.8.

[0094] The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.1 to 0.9. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.2 to 0.8. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.3 to 0.7. The ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heated surface of the porous material may be 0.4 to 0.6.

[0095] The heated surface of the porous material may have a width greater than the width of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a width less than the width of the heated surface of the porous material.

[0096] The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.9 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.8 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.7 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.6 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.5 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.4 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.3 or less. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.2 or less.

[0097] The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.1. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.2. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.3. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.4. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.5. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.6. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.7. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be at least 0.8.

[0098] The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.1 to 0.9. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.2 to 0.8. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.3 to 0.7. The ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material may be 0.4 to 0.6.

[0099] The heated surface of the porous material may have a length longer than the length of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a length shorter than the length of the heated surface of the porous material.

[0100] The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.9 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.8 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.7 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.6 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.5 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.4 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.3 or less. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.2 or less.

[0101] The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.1. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.2. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.3. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.4. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.5. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.6. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.7. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be at least 0.8.

[0102] The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.1 to 0.9. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.2 to 0.8. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.3 to 0.7. The ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material may be 0.4 to 0.6.

[0103] The liquid-absorbing surface of the porous material may have a width or length smaller than the width of the heated surface of the porous material.

[0104] The heated surface of the porous material may have a larger circumference than the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a smaller circumference than the heated surface of the porous material.

[0105] The heating surface of the porous material may have a diameter larger than the diameter of the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a diameter smaller than the diameter of the heating surface of the porous material.

[0106] The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.9 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.8 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.7 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.6 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.5 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.4 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.3 or less. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.2 or less.

[0107] The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.1. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.2. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.3. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.4. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.5. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.6. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.7. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material may be at least 0.8.

[0108] The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.1 to 0.9. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.2 to 0.8. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.3 to 0.7. The ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heated surface of the porous material may be 0.4 to 0.6.

[0109] The heated surface of the porous material may have a larger circumference than the liquid-absorbing surface of the porous material. The liquid-absorbing surface of the porous material may have a smaller circumference than the heated surface of the porous material.

[0110] The porous material may include a shape that tapers from the heated surface toward the liquid-absorbing surface.

[0111] The heated surface of the porous material may be convex in one or both of the first and second transverse directions, with the first transverse direction being perpendicular to the second transverse direction.

[0112] The inclusion of such porous ceramic materials can increase the surface area of ​​the heated surface without increasing its width. This can help improve the efficiency of the aerosol generation system when vaporizing the liquid aerosol-forming substrate, while avoiding the need to redesign other components of the aerosol generation system to accommodate the porous ceramic material.

[0113] Providing a heating surface that is convex along one or both of the first and second transverse directions may help avoid or minimize recirculation of the airflow adjacent to the heater assembly. In particular, a convex heating surface may help avoid or minimize recirculation of the airflow adjacent to the central region of the heater assembly. This may reduce the level of turbulence in the airflow adjacent to the heater assembly. Reducing the level of turbulence in the airflow adjacent to the heater assembly may improve the entrainment of vapors of aerosol-forming substrates in the airflow. This may improve the quality of aerosols generated by the aerosol generating system.

[0114] Improving the entrainment of vapor into the airflow through the aerosol generation system can avoid or reduce the condensation of vapor to form large droplets of the liquid aerosol-forming substrate. This can help avoid an unpleasant and undesirable user experience.

[0115] Improving the entrainment of vapor into the airflow through the aerosol generating system can prevent or reduce the condensation of vapor on the inner surface of the aerosol generating system. This can help prevent or minimize damage to the aerosol generating system and enable its optimal functioning.

[0116] The heated surface of the porous material may be convex in a single transverse direction.

[0117] The heated surface of the porous body may be convex in both the first transverse direction and the second transverse direction.

[0118] The heating surface of the porous material may be convex in one or both of the first and second transverse directions, based on the configuration of the heater assembly relative to one or more airflow paths in the aerosol generating system. The heater assembly may be configured to minimize the level of turbulence in the airflow adjacent to the heater assembly. For example, it may be advantageous for the heater assembly to be positioned within the aerosol generating system such that the air drawn into the aerosol generating system follows a curved path along at least a portion of the curved surface of the heater assembly.

[0119] The heating element may be convex in one or both of the first and second transverse directions.

[0120] The curvature of the heating element in the first transverse direction may be substantially the same as the curvature of the heated surface of the porous material in the first transverse direction. The curvature of the heating element in the second transverse direction may be substantially the same as the curvature of the heated surface of the porous material in the second transverse direction. The curvature of the heating element in both the first and second transverse directions may be substantially the same as the curvature of the heated surface of the porous material in both the first and second transverse directions, respectively.

[0121] The porous body may be a porous ceramic body. The heater assembly may include an insulating layer. The insulating layer may have a lower thermal conductivity than the porous ceramic body. The insulating layer may be placed between the porous ceramic body and the heating element. The insulating layer may be in contact with the porous ceramic body and the heating element. The insulating layer may be configured to reduce heat transfer from the heating element to the porous ceramic body.

[0122] The insulation layer may contain an insulating material. The insulating material may have a lower thermal conductivity than the porous ceramic body. The insulating material may have a higher porosity than the porous ceramic body. This has the advantage of providing an insulation layer that is easy to manufacture while being particularly effective in reducing energy loss.

[0123] The insulation layer may include a material having a thermal conductivity of less than 40 watts / meter Kelvin. This has the advantage of providing an insulation layer that is effective in reducing energy loss through the porous ceramic body. The insulation layer may also include a material having a thermal conductivity of less than 10 watts / meter Kelvin. This has the advantage of providing an insulation layer that is particularly effective in reducing energy loss through the porous ceramic body.

[0124] The insulating layer may extend throughout the space between the porous ceramic body and the heating element. This has the advantage of more effectively providing a barrier between the heating element and the porous ceramic body, and is therefore particularly effective in reducing energy loss through the porous ceramic body.

[0125] The insulating layer may contain one or more of the following: alumina, zirconia, zirconia containing magnesium oxide, glass ceramic, quartz, or porous polymer. The porous polymer may be polyimide.

[0126] The insulation layer may contain alumina having a thermal conductivity of 20-40 watts / meter Kelvin. The insulation layer may also contain materials having a thermal conductivity of less than 10 watts / meter Kelvin, such as zirconia, glass ceramics, or quartz, with or without magnesium oxide. The use of alumina, zirconia, glass ceramics, or quartz, with or without magnesium oxide, is advantageous because these materials are compatible with manufacturing processes involving sintering, and therefore heater assemblies having an insulation layer made of one of these materials are easier to manufacture.

[0127] The insulation layer may have a thickness of 0.1 to 2 millimeters. Insulation layers of this thickness are particularly suitable for reducing energy loss from the heating element to the porous ceramic body. Preferably, the insulation layer has a thickness of 0.5 to 1.5 millimeters. Insulation layers of this thickness are even more suitable for reducing energy loss from the heating element to the porous ceramic body.

[0128] The average pore size of a porous material can vary between the liquid-absorbing surface and the heated surface.

[0129] Providing a porous body that includes variations in pore size between the liquid-absorbing surface and the heating surface can, advantageously, help control the transport of the liquid aerosol-forming substrate from the storage portion to the heating element. Specifically, variations in pore size between the liquid-absorbing surface and the heating surface can enable the porous body to provide a consistent supply of the aerosol-forming substrate to the heating surface. This can, advantageously, avoid undesirable "dry heating." Furthermore, the porous body of the present invention can also, advantageously, prevent leakage of the liquid aerosol-forming substrate from the heating surface of the porous body.

[0130] The average pore size of a porous material can vary in any way between the liquid-absorbing surface and the heated surface. The average pore size can range from relatively large pores at the liquid-absorbing surface to relatively small pores at the heated surface.

[0131] Providing a porous body having a larger average pore diameter at the liquid absorption end and a smaller average pore diameter at the heating end can particularly facilitate the efficient movement of a liquid aerosol-forming substrate from the liquid absorption end to the heating end of the porous body without causing leakage. In particular, the inventors of the present invention have identified that the liquid aerosol-forming substrate moves from the liquid absorption end to the heating end of the porous body by capillary action. How quickly the liquid aerosol-forming substrate moves through the porous body depends on many factors, including but not limited to the pore shape, the surface tension between the liquid aerosol-forming substrate and the porous body, the viscosity of the liquid aerosol-forming substrate, and the surface tension of the liquid aerosol-forming substrate. The inventors of the present invention have identified the need to balance these factors while preventing leakage of the liquid aerosol-forming substrate and providing efficient movement of the liquid aerosol-forming substrate to the heating surface of the porous body.

[0132] Firstly, to provide efficient capillary flow of liquid through the porous material, the capillary pressure must exceed the viscous drag pressure. Secondly, to prevent leakage, the inertial force must not exceed the capillary pressure. These two requirements are met by providing a porous material having larger pores at the liquid absorption end and smaller pores at the heating end.

[0133] In particular, the inventors of the present invention recognized that the viscosity of the liquid aerosol-forming substrate changes with temperature. Specifically, the viscosity of the liquid aerosol-forming substrate decreases as its temperature increases. As a result, the viscosity of the liquid aerosol-forming substrate decreases as it moves from the liquid absorption surface to the heated surface through the porous material. Since the liquid aerosol-forming substrate is transported through the porous material by capillary force, the capillary force must overcome the viscous drawout of the liquid. Viscous resistance decreases as viscosity decreases. As a result, the capillary force required to move the liquid aerosol-forming substrate decreases toward the heated surface of the porous material while still maintaining the same flow rate. Consequently, the average pore size of the porous material can be reduced toward the heated surface without reducing the flow of the liquid aerosol-forming substrate through the porous material.

[0134] The heating element may comprise multiple tracks or track sections electrically arranged in parallel. The resistance of the heating element at room temperature may be 0.5 ohms to 1.5 ohms, preferably 0.7 ohms to 1.3 ohms, and more preferably 1 ohm. The resistance of the heating element may match the requirements of the control electronic circuit.

[0135] At least two of the electrically parallel heating tracks may have similar resistances to each other, or they may have identical resistances to each other. Preferably, all electrically parallel heating tracks have similar or identical resistances to each other. Electrically arranged heating tracks in parallel may have different resistances, which is particularly beneficial in heater assemblies where it is advantageous for zones of the heating element to generate different power levels. This may be, for example, to compensate for higher heat loss in the outer portion of the heating element. Thus, heating tracks on the outside or on the outer portion of the heating element may be designed to have lower resistances (and thus generate more heat) than the heating track in the center of the heating element.

[0136] The heating element may have multiple tracks or track sections. The multiple tracks or track sections may be electrically arranged in parallel. By being electrically arranged in parallel, the current flow is divided into separate parallel channels, which are then recombined.

[0137] The heating element may include a first connection pad and a second connection pad. The first or second connection pad (or the first and second connection pads) may be configured to allow connection to an external circuit. Openings or multiple openings within the heating element may isolate each track or track portion. The heating element may include at least one branching portion where the current is divided from the first connection pad to the track portions. The track portions define electrically parallel paths. The heating element may also include a merging portion. In the merging portion, the current is combined from the track portions defining electrically parallel paths to the second connection pad.

[0138] Various different arrangements of electrically arranged tracks or track sections are possible. The heating element may have two, three, four or more track sections that define electrically parallel paths.

[0139] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and can still flow through the heating element, i.e., the electrical connection between the first and second connecting pads is not broken. In contrast, in a simple meandering heater that defines a single electrical path between the first and second connecting pads, if a part of the meandering heating element is damaged or faulty, this causes an increase in local resistance, leading to increased power dissipation, increased resistance, and ultimately failure.

[0140] The inventors also identified that electrically parallel tracks or track sections have a surprising additional advantage. In such arrangements, if one track section fails, the heating element continues to operate and can operate advantageously for an initial, transient period, as the failure of one track or track section results in a higher energy density for the remaining tracks or track sections. In such cases, the same power is still provided, but over a smaller area, thus increasing the throughput of the aerosol generating substrate. Such failures, which cause an increase in current on the undamaged tracks or track sections, can ultimately affect the user experience. This can be mitigated by a mechanism to warn the user about the possibility of the heater assembly falling below optimal performance in the future. Electrically parallel tracks have the advantage of increasing the number of fume extractions before the heater completely fails, potentially increasing the heater's lifespan over the life of the device.

[0141] The heating element may comprise multiple tracks or track sections defining a path having at least one bend, the inner end of the bend being curved.

[0142] The inner end of a curved bend has the advantage of guiding the current so that it flows in a more evenly distributed manner around at least one bend. This reduces current concentration and limits the generation of hot spots.

[0143] The heating element may include multiple tracks or track sections having an electrical resistivity gradient perpendicular to the current flow at the corner, resulting in higher electrical resistivity on the inside of the corner and lower resistivity on the outside. Such gradients are beneficial for offsetting localized high current densities and reducing hotspot formation.

[0144] The heating element may comprise multiple tracks or track sections arranged at a distance between at least two of multiple tracks or track sections within a range of 200 to 150-300 micrometers.

[0145] All tracks or track sections may be spaced 200-300 micrometers apart from at least one other track section. This may have the advantage of providing a particularly efficient heater assembly in which the aerosol-forming substrate is efficiently vaporized.

[0146] An aerosol generating system is provided according to one embodiment of the present disclosure. The aerosol generating system may include the heater assembly described above. The heating element may be fluid permeable so that vapor is released from the heater assembly in the mean vapor discharge direction during use. The aerosol generating system may further include an air intake and an aerosol outlet. The air intake may be in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system. The heater assembly may be arranged in fluid communication with the airflow path so that air flows through the heater assembly in the mean airflow direction. The heater assembly and the airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0147] Advantageously, by arranging the heater assembly and airflow path so that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees, the mean airflow direction does not directly oppose the mean vapor discharge direction. Therefore, the momentum of the vapor and airflow is not reduced as much as when the mean airflow direction directly opposes the mean vapor discharge direction. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generation system. Consequently, the likelihood of aerosol condensation occurring within the aerosol generation system is reduced.

[0148] The average vapor emission direction may be substantially perpendicular to the heated surface. As used herein, the term “substantially perpendicular” means 90 degrees plus or minus 10 degrees, preferably plus or minus 5 degrees.

[0149] The advantage of the mean vapor release direction being substantially perpendicular to the heated surface is that, since the vapor is released substantially perpendicular to the heated surface of the porous material, the mean vapor release direction can be simply oriented relative to the mean airflow direction. Therefore, by appropriately angling the heater assembly with respect to the airflow in the airflow path, or vice versa, the desired angle between the mean vapor release direction and the mean airflow direction can be achieved.

[0150] The heater assembly and airflow path may be arranged such that the angle between the average vapor discharge direction and the average airflow direction is less than 110 degrees, preferably less than 100 degrees.

[0151] The heater assembly and airflow path may be arranged such that the angle between the mean vapor release direction and the mean airflow direction is approximately 90 degrees. This arrangement causes the vapor to be released at an angle substantially perpendicular to the mean airflow direction. The mean vapor release direction has no velocity or directional component opposite to the airflow direction, and therefore the loss of momentum in the airflow is reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generating system. Furthermore, the entrainment of vapor into the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is reduced.

[0152] The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 90 degrees. In this arrangement, the mean vapor discharge direction does not have a velocity or directional component opposite to the airflow direction, and in fact has a velocity and directional component in the same direction as the mean airflow direction. Thus, momentum loss of the airflow is further reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path and makes it less likely for vapor to collide with the internal surfaces of the aerosol generation system. Furthermore, vapor entrainment into the airflow is improved. Thus, the likelihood of aerosol condensation occurring within the aerosol generation system is reduced.

[0153] The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is approximately 45 degrees. The heater assembly and airflow path may be arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 45 degrees.

[0154] The heater assemblies and airflow paths may be arranged such that the mean vapor discharge direction and the mean airflow direction are substantially the same. In this arrangement, since the mean vapor discharge direction and the mean airflow direction are the same, there is virtually no loss of momentum in the airflow. This reduces the tendency for recirculation and turbulence to occur within the airflow path and reduces the likelihood of vapor colliding with the internal surfaces of the aerosol generating system. Furthermore, vapor entrainment into the airflow is improved. Consequently, the likelihood of aerosol condensation occurring within the aerosol generating system is reduced.

[0155] The cross-sectional area of ​​the airflow path within the heater assembly may be configured such that the airflow velocity during use is 0.1 to 2 meters / second, preferably 0.5 to 1.5 meters / second, and more preferably approximately 1 meter / second. It has been found that airflow velocities within this range effectively entrain the vapor released from different designs of the heating element without excessively cooling the heating element.

[0156] The heating element may comprise a porous layer of conductive material. Advantageously, a heating element comprising a porous layer of conductive material allows for resistance heating and also allows electric current to flow through the heating element, enabling vapor to move through the pores within its porous structure. Therefore, vapor release occurs through the porous heating element. This avoids the accumulation of vapor pressure beneath the heating element and high-speed vapor release at the sides of the heating element. The inventors found that this arrangement generates consistent vapor across the heating element, resulting in a low vapor release velocity of approximately 0.1 meters / second. Such a low vapor release velocity means that the vapor is easily carried by an airflow that reduces vapor collisions on the inner walls of the aerosol generating system.

[0157] According to embodiments of the present disclosure, a cartridge is provided. The cartridge may comprise a heater assembly. The cartridge may include a liquid storage portion for holding an aerosol-forming substrate. The heater assembly may comprise a heating element for vaporizing the liquid aerosol-forming substrate. The heater assembly may comprise a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body may have a liquid-absorbing surface. The porous body may have a heating surface. The heating element may be located on the heating surface of the porous body. The liquid-absorbing surface of the porous body may have a different area from the heating surface of the porous body. The porous body may include a porous ceramic body or a porous glass body.

[0158] According to embodiments of the present disclosure, a cartridge is provided comprising a heater assembly and a liquid storage portion for holding a liquid aerosol forming substrate, wherein the heater assembly comprises a heating element for vaporizing the liquid aerosol forming substrate and a porous body for transporting the liquid aerosol forming substrate to the heating element, the porous body having a liquid absorption surface and a heating surface, the heating element being located on the heating surface of the porous body, the liquid absorption surface of the porous body having an area different from the area of ​​the heating surface of the porous body, and the porous body including a porous ceramic body or a porous glass body.

[0159] The cartridge may include a liquid aerosol-forming substrate within the liquid storage portion. The liquid aerosol-forming substrate may be as described above.

[0160] The porous body may be fluid-connected to the liquid storage portion. The liquid-absorbing surface of the porous body may be fluid-connected to the liquid storage portion.

[0161] The liquid storage portion may be disposed on the liquid-absorbing surface of a porous material.

[0162] An aerosol generation system is provided. The aerosol generation system may comprise a cartridge and an aerosol generator. The cartridge may comprise a heater assembly. The cartridge may include a liquid storage portion for holding an aerosol-forming substrate. The heater assembly may comprise a heating element for vaporizing the liquid aerosol-forming substrate. The heater assembly may comprise a porous body for transporting the liquid aerosol-forming substrate to the heating element. The porous body may have a liquid-absorbing surface. The porous body may have a heating surface. The heating element may be located on the heating surface of the porous body. The liquid-absorbing surface of the porous body may have a different area from the heating surface of the porous body. The porous body may include a porous ceramic body or a porous glass body. The aerosol generator may comprise a power supply for supplying power to the heating element. The aerosol generator may comprise a control circuit configured to control the supply of power from the power supply to the heating element.

[0163] An aerosol generating system is provided, comprising a cartridge and an aerosol generator, wherein the cartridge comprises a heater assembly and a liquid storage portion for holding a liquid aerosol forming substrate, and the heater assembly comprises a heating element for vaporizing the liquid aerosol forming substrate and a porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface, the heating element is located on the heating surface of the porous body, the liquid absorption surface of the porous body has an area different from the area of ​​the heating surface of the porous body, and the porous body includes a porous ceramic body or a porous glass body. The aerosol generator comprises a power supply for supplying power to the heating element and a control circuit configured to control the power supply from the power supply to the heating element.

[0164] The cartridge may include a liquid aerosol-forming substrate within the liquid storage portion. The liquid aerosol-forming substrate may be as described above.

[0165] The aerosol generating system may be portable. The aerosol generating system may be comparable in size to a conventional cigar or cigarette.

[0166] The cartridge may be detachably coupled to the aerosol generator.

[0167] The aerosol-forming substrate may be liquid at room temperature. The aerosol-forming substrate may comprise both a liquid component and a solid component. The liquid aerosol-forming substrate may contain nicotine. The nicotine-containing liquid aerosol-forming substrate may be a nicotine salt matrix. The liquid aerosol-forming substrate may contain plant-derived materials. The liquid aerosol-forming substrate may contain tobacco. The liquid aerosol-forming substrate may contain tobacco-containing materials that include volatile tobacco-flavored compounds released from the aerosol-forming substrate upon heating. The liquid aerosol-forming substrate may contain homogenized tobacco materials. The liquid aerosol-forming substrate may contain non-tobacco-containing materials. The liquid aerosol-forming substrate may contain homogenized plant-derived materials.

[0168] A liquid aerosol-forming substrate may comprise one or more aerosol-forming elements. An aerosol-forming element is any suitable known compound, or mixture of compounds, that facilitates the formation of a high-density, stable aerosol during use and is substantially resistant to thermal decomposition at the system's operating temperature. Examples of suitable aerosol-forming elements include glycerin and propylene glycol. Suitable aerosol-forming elements are well known in the art and include, but are not limited to, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (e.g., dimethyl dodecanediol, dimethyl tetradecanediol). The liquid aerosol-forming substrate may also contain water, a solvent, ethanol, plant extracts, and natural or artificial flavors.

[0169] The liquid aerosol-forming substrate may contain nicotine and at least one aerosol-forming agent. The aerosol-forming agent may be glycerin or propylene glycol. The aerosol-forming agent may contain both glycerin and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration of about 0.5% to about 10%, for example, about 2%.

[0170] The airflow path may pass through the liquid storage portion. For example, the liquid storage portion may have an annular cross-section defining an internal passage or aerosol channel, and the airflow path may extend through the internal passage or aerosol channel of the liquid storage portion.

[0171] The cartridge may include a cartridge housing. The cartridge housing may be formed from a durable material. The cartridge housing may be formed from a liquid-impermeable material. The cartridge housing may be formed from a moldable plastic material such as polypropylene (PP) or polyethylene terephthalate (PET), or from a copolymer such as Tritan® made from three monomers, namely dimethyl terephthalate (DMT), cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). The cartridge housing of the cartridge may define a portion of the liquid storage section. The cartridge housing and the liquid storage section may be formed integrally. Alternatively, the liquid storage section may be formed separately from the cartridge housing or disposed within the cartridge housing.

[0172] The aerosol generator may include a power supply for supplying power to the heater assembly. The aerosol generator may also include a control circuit for controlling the power supply from the power supply to the heater assembly. The cartridge may be detachably coupled to the aerosol generator.

[0173] The aerosol generator may include a housing. The housing may be elongated. The housing may be made of any suitable material, or a combination of such materials. Examples of suitable materials include metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. The material is preferably lightweight and not brittle.

[0174] The aerosol generator housing may define a cavity for receiving a portion of the cartridge. The aerosol generator may have a connecting terminal configured to connect the aerosol generator to the cartridge. The connecting terminal may include a cavity for receiving the cartridge.

[0175] The power source may be any suitable power source. Preferably, the power source is a DC power source. The power source may be a battery. The battery may be a lithium-based battery, for example, a lithium cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a lithium polymer battery. The battery may be a nickel-metal hydride battery or a nickel-cadmium battery. The power source may be another form of charge storage device, such as a capacitor. The power source may be rechargeable and may be configured to undergo multiple charge-discharge cycles. The power source may have a capacity that allows for the storage of sufficient energy for one or more user experiences of the aerosol generating system. For example, the power source may have a capacity that allows for continuous aerosol generation for about six minutes, or a multiple of six minutes, corresponding to the typical time it takes to smoke one conventional cigarette. In another embodiment, the power source may have a capacity that allows for a predetermined number of smoking sessions or for intermittent startup of the aerosol generating system.

[0176] The control circuit may include any suitable controller or electrical component. The controller may include memory. Information for carrying out the above-described method may be stored in memory. The control circuit may include a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, an application-specific integrated circuit (ASIC), or other electronic circuit capable of providing control. The control circuit may be configured to supply power to the heating element continuously after the device is started up, or to supply power intermittently, such as with each smoke extraction. Power may be supplied to the heating element in the form of current pulses, for example by pulse-width modulation (PWM).

[0177] Features described in relation to one of the above embodiments may be equally applicable to other embodiments of the present disclosure. [Examples]

[0178] The present invention is defined in the claims. However, a non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with one or more features of other embodiments, forms, or aspects described herein.

[0179] Example 1. A heater assembly for an aerosol generation system, wherein the heater assembly comprises a heating element for vaporizing a liquid aerosol forming substrate, A heater assembly comprising a porous body for transporting a liquid aerosol-forming substrate to a heating element, wherein the porous body has a liquid-absorbing surface and a heating surface, the heating element is located on the heating surface of the porous body, the liquid-absorbing surface of the porous body has an area different from the area of ​​the heating surface of the porous body, and the porous body includes a porous ceramic body or a porous glass body. Example 2. The heater assembly described in Example 1, wherein the heating surface area of ​​the porous material is smaller than the liquid-absorbing surface area of ​​the porous material. Example 3. A heater assembly according to either Example 1 or 2, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is 0.9 or less. Example 4. A heater assembly according to any one of Examples 1 to 3, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is at least 0.1. Example 5. A heater assembly according to any one of Examples 1 to 4, wherein the ratio of the area of ​​the heating surface of the porous material to the area of ​​the liquid-absorbing surface of the porous material is 0.1 to 0.9. Example 6. A heater assembly according to any one of Examples 1 to 5, wherein the heating surface of the porous material has a width smaller than the width of the liquid-absorbing surface of the porous material. Example 7. The heater assembly according to Example 6, wherein the ratio of the width of the heating surface of the porous material to the width of the liquid-absorbing surface of the porous material is 0.9 or less. Example 8. A heater assembly according to Example 6 or Example 7, wherein the ratio of the width of the heating surface of the porous material to the width of the liquid-absorbing surface of the porous material is at least 0.1. Example 9. A heater assembly according to any one of Examples 6 to 8, wherein the ratio of the width of the heating surface of the porous material to the width of the liquid-absorbing surface of the porous material is 0.1 to 0.9. Example 10. A heater assembly according to any one of Examples 1 to 9, wherein the heating surface of the porous material is shorter in length than the liquid-absorbing surface of the porous material. Example 11. The heater assembly according to Example 10, wherein the ratio of the length of the heating surface of the porous material to the length of the liquid-absorbing surface of the porous material is 0.9 or less. Example 12. A heater assembly according to Example 10 or Example 11, wherein the ratio of the length of the heating surface of the porous material to the length of the liquid-absorbing surface of the porous material is at least 0.1. Example 13. A heater assembly according to any of Examples 10 to 12, wherein the ratio of the length of the heating surface of the porous material to the length of the liquid-absorbing surface of the porous material is 0.1 to 0.9. Example 14. A heater assembly according to Example 1 or Example 2, wherein the heating surface of the porous material has a diameter smaller than the diameter of the liquid-absorbing surface of the porous material. Example 15. The heater assembly according to Example 14, wherein the ratio of the diameter of the heating surface of the porous material to the diameter of the liquid-absorbing surface of the porous material is 0.9 or less. Example 16. A heater assembly according to Example 14 or Example 15, wherein the ratio of the diameter of the heating surface of the porous material to the diameter of the liquid-absorbing surface of the porous material is at least 0.1. Example 17. A heater assembly according to any of Examples 14 to 16, wherein the ratio of the diameter of the heating surface of the porous material to the diameter of the liquid-absorbing surface of the porous material is 0.1 to 0.9. Example 18. A heater assembly according to any one of Examples 1 to 17, wherein the porous body has a shape that tapers from the liquid-absorbing surface of the porous body toward the heating surface of the porous body. Example 19. A heater assembly according to any of Examples 1 to 18, wherein the porous body has a trapezoidal prism shape or a truncated pyramidal shape. Example 20. A heater assembly according to any one of Examples 1 to 19, wherein the heating surface has an area of ​​at least 1 square millimeter. Example 21. A heater assembly according to any of Examples 1 to 20, wherein the heating surface has an area of ​​30 square millimeters or less. Example 22. A heater assembly according to any of Examples 1 to 21, wherein the heating surface has an area of ​​1 square millimeter to 30 square millimeters. Example 23. A heater assembly according to any of Examples 1 to 22, wherein the liquid-absorbing surface has an area of ​​at least 2 square millimeters. Example 24. A heater assembly according to any of Examples 1 to 23, wherein the liquid absorption surface has an area of ​​100 square millimeters or less. Example 25. A heater assembly according to any of Examples 1 to 24, wherein the liquid-absorbing surface has an area of ​​2 square millimeters to 100 square millimeters. Example 26. The heater assembly described in Example 1, wherein the area of ​​the liquid-absorbing surface of the porous material is smaller than the area of ​​the heating surface of the porous material. Example 27. The heater assembly according to Example 26, wherein the ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heating surface of the porous material is 0.9 or less. Example 28. The heater assembly according to Example 26 or 27, wherein the ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heating surface of the porous material is at least 0.1. Example 29. A heater assembly according to any of Examples 26 to 28, wherein the ratio of the area of ​​the liquid-absorbing surface of the porous material to the area of ​​the heating surface of the porous material is 0.1 to 0.9. Example 30. A heater assembly according to any of Examples 26 to 29, wherein the liquid-absorbing surface of the porous material has a width smaller than the width of the heating surface of the porous material. Example 31. The heater assembly according to Example 30, wherein the ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material is 0.9 or less. Example 32. A heater assembly according to Example 30 or Example 31, wherein the ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material is at least 0.1. Example 33. A heater assembly according to any of Examples 30 to 32, wherein the ratio of the width of the liquid-absorbing surface of the porous material to the width of the heating surface of the porous material is 0.1 to 0.9. Example 34. A heater assembly according to any of Examples 26 to 33, wherein the liquid-absorbing surface of the porous material is shorter in length than the heating surface of the porous material. Example 35. The heater assembly according to Example 34, wherein the ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material is 0.9 or less. Example 36. A heater assembly according to Example 34 or Example 35, wherein the ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material is at least 0.1. Example 37. A heater assembly according to any of Examples 34 to 36, wherein the ratio of the length of the liquid-absorbing surface of the porous material to the length of the heating surface of the porous material is 0.1 to 0.9. Example 38. The heater assembly according to Example 26, wherein the liquid-absorbing surface of the porous material has a diameter smaller than the diameter of the heating surface of the porous material. Example 39. The heater assembly according to Example 38, wherein the ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material is 0.9 or less. Example 40. A heater assembly according to Example 38 or Example 39, wherein the ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material is at least 0.1. Example 41. A heater assembly according to any of Examples 38 to 40, wherein the ratio of the diameter of the liquid-absorbing surface of the porous material to the diameter of the heating surface of the porous material is 0.1 to 0.9. Example 42. A heater assembly according to any one of Examples 26 to 41, wherein the porous body has a shape that tapers from the heating surface of the porous body toward the liquid-absorbing surface of the porous body. Example 43. A heater assembly according to any of Examples 26 to 31, wherein the porous body has a trapezoidal prism shape or a truncated pyramidal shape. Example 44. A heater assembly according to any one of Examples 26 to 43, wherein the liquid-absorbing surface has an area of ​​at least 1 square millimeter. Example 45. A heater assembly according to any one of Examples 26 to 44, wherein the liquid absorption surface has an area of ​​30 square millimeters or less. Example 46. A heater assembly according to any one of Examples 26 to 45, wherein the liquid-absorbing surface has an area of ​​1 square millimeter to 30 square millimeters. Example 47. A heater assembly according to any one of Examples 26 to 46, wherein the heating surface has an area of ​​at least 2 square millimeters. Example 48. A heater assembly according to any one of Examples 26 to 47, wherein the heating surface has an area of ​​100 square millimeters or less. Example 49. A heater assembly according to any one of Examples 26 to 48, wherein the heating surface has an area of ​​2 square millimeters to 100 square millimeters. Example 50. A heater assembly according to any of Examples 1 to 49, wherein the heating surface of the porous body is convex in one or both of the first transverse direction and the second transverse direction, and the first transverse direction is perpendicular to the second transverse direction. Example 51. A heater assembly according to any of Examples 1 to 50, wherein the average pore size of the porous material changes between the liquid absorption surface and the heating surface. Example 52. The porous body has a heating end and a liquid absorption end, with the heating surface located at the heating end and the liquid absorption surface located at the liquid absorption end. The heater assembly according to Example 51, wherein the porous body has a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end, and the first average pore diameter is larger than the second average pore diameter. Example 53. A heater assembly according to any one of Examples 1 to 52, comprising an insulating layer having a lower thermal conductivity than the porous ceramic body, wherein the insulating layer is disposed between the porous ceramic body and the heating element and is in contact with the porous ceramic body and the heating element, and the insulating layer is configured to reduce heat transfer from the heating element to the porous ceramic body. Example 54. A heater assembly according to any one of Examples 1 to 53, wherein the heating element comprises multiple tracks or track sections electrically arranged in parallel. Example 55. A heater assembly according to any one of Examples 1 to 54, wherein the heating element comprises a plurality of tracks or track portions defining a path having at least one bend, and the inner edge of the bend is curved. Example 56. A heater assembly according to any of Examples 1 to 55, wherein the heating element and the porous body are integrally formed. Example 57. A heater assembly according to any of Examples 1 to 56, wherein the heating element and the porous body are molded as a single monolithic piece. Example 58. A heater assembly according to any of Examples 1 to 57, wherein the heating element is the doped portion of a porous material. Example 59. A heater assembly according to any of Examples 1 to 58, wherein the heating element is located on the heating surface of a porous body and bonded to the heating surface of the porous body. Example 60. A cartridge for an aerosol generating system comprising a heater assembly described in any of Examples 1 to 59, and a liquid storage portion for holding a liquid aerosol forming substrate, wherein the liquid storage portion is disposed on a porous liquid-absorbing surface. Example 61. An aerosol generating system comprising an aerosol generating device having the cartridge described in Example 60, a power supply for supplying power to a heating element, and a control circuit configured to control the power supply from the power supply to the heating element.

[0180] Here, we will further describe the embodiment with reference to the attached drawings.

[0181] Figures 1 and 2 show schematic diagrams of a first embodiment of a heater assembly 100 for an aerosol generation system. The heater assembly includes a heating element 110 and a porous body 120.

[0182] The heating element 110 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 110 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 110 to electric current.

[0183] The porous body 120 is configured to transport the liquid aerosol-forming substrate to the heating element 110. In other words, the porous body 120 supplies the liquid aerosol-forming substrate to the heating element 110.

[0184] The porous body 120 has a first end face and an opposing second end face. The first end face is the liquid absorption surface 130, and the second end face is the heating surface 140. In this embodiment, both the liquid absorption surface 130 and the heating surface 140 are substantially flat surfaces. The porous body 120 also has a plurality of sides extending between the liquid absorption surface 130 and the heating surface 140.

[0185] In this embodiment, as will be discussed in more detail below, the porous body 120 has a first side surface 150 facing the second side surface 160, and a third side surface 170 facing the fourth side surface 180.

[0186] The porous body 120 contains a plurality of pores, which are open pores. The plurality of pores are interconnected to provide a fluid pathway for the liquid aerosol-forming substrate through the porous body 120 from the liquid absorption surface 130 to the heating surface 140. The porous body 120 is formed from a material that does not chemically interact with the liquid aerosol-forming substrate. In this embodiment, the porous body 120 is a porous ceramic body, which may be formed from, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2). In another embodiment, the porous body 120 may be, for example, a porous glass body.

[0187] The heating element 110 is located on the heating surface 140 of the porous body 120. In the embodiments shown in Figures 1 and 2, the heating element 110 is a porous film that extends substantially over the entire heating surface 140.

[0188] The liquid-absorbing surface 130 of the porous body 120 has a different area from the heating surface 140 of the porous body 120. Specifically, in the embodiments shown in Figures 1 and 2, the area of ​​the heating surface 140 is smaller than the area of ​​the liquid-absorbing surface 130.

[0189] In the embodiments shown in Figures 1 and 2, the length of the heating surface 140 is shorter than the length of the liquid absorption surface 130, so the heating surface 140 has a smaller area than the liquid absorption surface 130. In addition, or in another embodiment, the width of the heating surface 140 is smaller than the width of the liquid absorption surface 130, so the heating surface 140 may have a smaller area than the liquid absorption surface 130.

[0190] In the embodiments shown in Figures 1 and 2, the porous body 120 is formed as a trapezoidal prism. With the porous body 120 having a trapezoidal prism shape, both the first side 150 and the second side 160 are trapezoidal, particularly isosceles trapezoidal, both the third side 170 and the fourth side 180 are rectangular, and both the liquid absorption surface 130 and the heating surface 140 are rectangular. In another embodiment, the liquid absorption surface 130 and the heating surface 140 may have a square shape.

[0191] The porous body 120 tapers from the liquid-absorbing surface 130 towards the heating surface 140. In other words, the cross-sectional area of ​​the porous body 120 gradually decreases from the liquid-absorbing surface 130 towards the heating surface 140. In the embodiments shown in Figures 1 and 2, the length of the porous body 120 decreases and tapers from the liquid-absorbing surface 130 towards the heating surface 140.

[0192] In the embodiments shown in Figures 1 and 2, the pore diameter of the porous body 120 is the same between the liquid absorption surface 130 and the heating surface 140.

[0193] In an alternative embodiment, the pore size of the pores within the porous body 120 varies between the liquid absorption surface 130 and the heating surface 140.

[0194] The porous body 120 may include a heating end and a liquid absorption end, with the heating surface 140 located at the heating end and the liquid absorption surface 130 located at the liquid absorption end. The porous body may include a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end. The first average pore diameter is larger than the second average pore diameter.

[0195] In this alternative embodiment, the first pore diameter at the liquid absorption end is approximately 150 micrometers. The second pore diameter at the heating end is approximately 20 micrometers. The pore diameter changes linearly between the first and second pore diameters, providing a pore diameter gradient between the liquid absorption end and the heating end of the porous body 120.

[0196] The pore structure and pore diameter gradient of the porous body 120 are achieved by etching the pores with a portion of silicon carbide.

[0197] Figure 3 shows a schematic diagram of a second embodiment of the heater assembly 200 for an aerosol generation system. The heater assembly includes a heating element 210 and a porous body 220.

[0198] The heating element 210 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 210 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 210 to electric current.

[0199] The porous body 220 is configured to transport the liquid aerosol-forming substrate to the heating element 210. In other words, the porous body 220 supplies the liquid aerosol-forming substrate to the heating element 210.

[0200] The porous body 220 has a first end face and an opposing second end face. The first end face is the liquid absorption surface 230, and the second end face is the heating surface 240. In this embodiment, both the liquid absorption surface 230 and the heating surface 240 are substantially flat surfaces. The porous body 220 also has a plurality of sides extending between the liquid absorption surface 230 and the heating surface 240.

[0201] In this embodiment, as will be discussed in more detail below, the porous body 220 has a first side surface 250 facing the second side surface 260, and a third side surface 270 facing the fourth side surface 280.

[0202] The porous body 220 contains a plurality of pores. The plurality of pores are interconnected to provide a fluid path for the liquid aerosol-forming substrate through the porous body 220 from the liquid absorption surface 230 to the heating surface 240. The porous body 220 is formed from a material that does not chemically interact with the liquid aerosol-forming substrate. In this embodiment, the porous body 220 is a porous ceramic body and may be formed from, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2). In another embodiment, the porous body 220 may be, for example, a porous glass body.

[0203] The heating element 210 is located on the heating surface 240 of the porous body 220. In the embodiment shown in Figure 3, the heating element 210 is an elongated porous film that extends in a meandering pattern across the heating surface 240.

[0204] The liquid-absorbing surface 230 of the porous body 220 has a different area than the heating surface 240 of the porous body 220. Specifically, in the embodiment shown in Figure 3, the area of ​​the heating surface 240 is smaller than the area of ​​the liquid-absorbing surface 230.

[0205] In the embodiment shown in Figure 3, the heating surface 240 has a smaller area than the liquid absorption surface 230 because the width of the heating surface 240 is smaller than the width of the liquid absorption surface 230, and the length of the heating surface 240 is shorter than the length of the liquid absorption surface 230.

[0206] In the embodiment shown in Figure 3, the porous body 220 is shaped as a truncated pyramidal

[0207] The porous body 220 tapers from the liquid-absorbing surface 230 towards the heating surface 240. In other words, the cross-sectional area of ​​the porous body 220 gradually decreases from the liquid-absorbing surface 230 towards the heating surface 240. In the embodiment shown in Figure 3, both the length and width of the porous body 220 decrease and taper from the liquid-absorbing surface 230 towards the heating surface 240.

[0208] Figure 4 shows a schematic diagram of a third embodiment of a heater assembly 300 for an aerosol generating system. The heater assembly includes a heating element 310 and a porous body 320.

[0209] The heating element 310 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 310 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 310 to electric current.

[0210] The porous body 320 is configured to transport the liquid aerosol-forming substrate to the heating element 310. In other words, the porous body 320 supplies the liquid aerosol-forming substrate to the heating element 310.

[0211] The porous body 320 has a first end face and an opposing second end face. The first end face is a liquid absorption surface 330, and the second end face is a heating surface 340. In this embodiment, both the liquid absorption surface 330 and the heating surface 340 are substantially flat surfaces. The porous body 320 also has a side surface 350 extending between the liquid absorption surface 330 and the heating surface 340.

[0212] The porous body 320 contains a plurality of pores. The plurality of pores are interconnected to provide a fluid path for the liquid aerosol-forming substrate through the porous body 320 from the liquid absorption surface 330 to the heating surface 340. The porous body 320 is formed from a material that does not chemically interact with the liquid aerosol-forming substrate. In this embodiment, the porous body 320 is a porous ceramic body and may be formed from, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2). In another embodiment, the porous body 320 may be, for example, a porous glass body.

[0213] The heating element 310 is located on the heating surface 340 of the porous body 320. In the embodiment shown in Figure 4, the heating element 310 is an elongated porous film that extends in a meandering pattern around and on the heating surface 340.

[0214] The liquid-absorbing surface 330 of the porous body 320 has a different area than the heating surface 340 of the porous body 320. Specifically, in the embodiment shown in Figure 4, the area of ​​the heating surface 340 is smaller than the area of ​​the liquid-absorbing surface 330.

[0215] In the embodiment shown in Figure 4, the diameter of the heated surface 340 is smaller than the diameter of the liquid absorption surface 330, so the heated surface 340 has a smaller area than the liquid absorption surface 330.

[0216] In the embodiment shown in Figure 4, the porous body 320 is shaped as a truncated cone. When the porous body 320 has a truncated cone shape, the side surface 350 has a curved shape, and both the liquid absorption surface 330 and the heating surface 340 have a circular shape. In another embodiment, the liquid absorption surface 330 and the heating surface 340 may have an elliptical shape.

[0217] The porous body 320 tapers from the liquid-absorbing surface 330 towards the heating surface 340. In other words, the cross-sectional area of ​​the porous body 320 gradually decreases from the liquid-absorbing surface 330 towards the heating surface 340. In the embodiment shown in Figure 4, both diameters of the porous body 320 decrease from the liquid-absorbing surface 330 towards the heating surface 340, resulting in a taper.

[0218] Figures 5 and 6 show schematic diagrams of a fourth embodiment of a heater assembly 400 for an aerosol generation system. The heater assembly includes a heating element 410 and a porous body 420.

[0219] The heating element 410 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 410 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 410 to electric current.

[0220] The porous body 420 is configured to transport the liquid aerosol-forming substrate to the heating element 410. In other words, the porous body 420 supplies the liquid aerosol-forming substrate to the heating element 410.

[0221] The porous body 420 has a first end face and an opposing second end face. The first end face is the liquid absorption surface 430, and the second end face is the heating surface 440. In this embodiment, both the liquid absorption surface 430 and the heating surface 440 are substantially flat surfaces. The porous body 420 also has a plurality of sides extending between the liquid absorption surface 430 and the heating surface 440.

[0222] In this embodiment, as will be discussed in more detail below, the porous body 420 has a first side surface 450 facing the second side surface 460, and a third side surface 470 facing the fourth side surface 480.

[0223] The porous body 420 contains a plurality of pores. The plurality of pores are interconnected to provide a fluid path for the liquid aerosol-forming substrate through the porous body 420 from the liquid absorption surface 430 to the heating surface 440. The porous body 120 is formed from a material that does not chemically interact with the liquid aerosol-forming substrate. In this embodiment, the porous body 420 is a porous ceramic body and may be formed from, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2). In another embodiment, the porous body 420 may be, for example, a porous glass body.

[0224] The heating element 410 is located on the heating surface 440 of the porous body 420. In the embodiments shown in Figures 5 and 6, the heating element 410 is a porous film that extends substantially over the entire heating surface 440.

[0225] The liquid-absorbing surface 430 of the porous body 420 has a different area than the heating surface 440 of the porous body 420. Specifically, in the embodiments shown in Figures 5 and 6, the area of ​​the liquid-absorbing surface 430 is smaller than the area of ​​the heating surface 440.

[0226] In the embodiments shown in Figures 5 and 6, the length of the heating surface 440 is greater than the length of the liquid absorption surface 430, so the heating surface 440 has a larger area than the liquid absorption surface 430. In addition, or in another embodiment, the width of the heating surface 440 is greater than the width of the liquid absorption surface 430, so the heating surface 440 may have a larger area than the liquid absorption surface 430.

[0227] In the embodiments shown in Figures 5 and 6, the porous body 420 is formed as a trapezoidal prism. With the porous body 420 having a trapezoidal prism shape, the first side 450 and the second side 460 are both trapezoidal, particularly isosceles trapezoidal, the third side 470 and the fourth side 480 are both rectangular, and the liquid absorption surface 430 and the heating surface 440 are both rectangular. In another embodiment, the liquid absorption surface 430 and the heating surface 440 may have a square shape.

[0228] The porous body 420 tapers from the heated surface 440 towards the liquid-absorbing surface 430. In other words, the cross-sectional area of ​​the porous body 420 gradually increases from the liquid-absorbing surface 430 towards the heated surface 440. In the embodiments of Figures 5 and 6, the length of the porous body 420 increases from the liquid-absorbing surface 430 towards the heated surface 440 and tapers.

[0229] Figure 7 shows a schematic diagram of a fourth embodiment of a heater assembly 500 for use in an aerosol generation system. The heater assembly 500 comprises a heating element 510 for vaporizing a liquid aerosol-forming substrate. The heater assembly 500 also comprises a porous ceramic body 520 for transporting the liquid aerosol-forming substrate to the heating element 510. The porous ceramic body 520 has a liquid-absorbing surface 530 and an opposing heating surface 540. The heating element 510 is located on the heating surface 540 of the porous ceramic body 520.

[0230] The heated surface 540 of the porous ceramic body 520 is curved. In particular, the heated surface 540 of the porous ceramic body 520 is curved in a convex shape in a single transverse direction.

[0231] The porous body 520 has a prismatic shape. When viewing a cross-section of the porous body 520 in the direction of its major axis perpendicular to the curvature direction, the heated surface 540 of the porous body 520 is shown as a circular arc. The porous body 520 has two symmetrical planes in the direction of its major axis.

[0232] The heating surface 540 of the porous ceramic body 520 has a width 541 that is substantially the same as the width of the porous ceramic body 520 and substantially the same as the width of the heater assembly 500. The heating surface 540 of the porous ceramic body 520 has a width of approximately 5 millimeters.

[0233] The heated surface 540 of the porous ceramic body 520 has a length or thickness 542 of approximately 1 millimeter. The porous ceramic body 520 has a length or thickness 543 of approximately 3 millimeters.

[0234] The heated surface 520 of the porous ceramic body has a radius of curvature of approximately 3.6 millimeters. The heated surface 520 of the porous ceramic body has a surface area of ​​approximately 28 square millimeters.

[0235] The porous body 520 has four longitudinal surfaces or side walls extending from the liquid-absorbing surface 530 to the heating surface 540. The four side walls are substantially perpendicular to the liquid-absorbing surface 530, which is substantially flat. The liquid-absorbing surface 530 has a square shape.

[0236] The heating element 510 is a resistance heating element.

[0237] The heating element 510 is curved. In particular, the curvature of the heating element is substantially the same as the curvature of the heating surface 540 of the porous ceramic body 520. Thus, the heating element 510 is also curved convexly in a single transverse direction.

[0238] The heating element 510 is located directly on the heating surface 540 of the porous ceramic body 520. The heating element 510 extends over most of the heating surface 540 of the porous ceramic body 520. Substantially the entire heating element 510 is in contact with the heating surface 540 of the porous ceramic body 520.

[0239] Figure 8 shows a schematic diagram of a fourth embodiment of the heater assembly 600 for an aerosol generating system. The heater assembly includes a heating element 610 and a porous body 620.

[0240] The heating element 610 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 610 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 610 to electric current.

[0241] The porous body 620 is configured to transport the liquid aerosol-forming substrate to the heating element 610. In other words, the porous body 620 supplies the liquid aerosol-forming substrate to the heating element 610.

[0242] The porous body 620 has a first end face and a second end face opposite thereto. The first end face is a liquid absorption surface 630, and the second end face is a heating surface 640. In this embodiment, both the liquid absorption surface 630 and the heating surface 640 are substantially flat surfaces. The porous body 620 also has a plurality of side faces extending between the liquid absorption surface 630 and the heating surface 640.

[0243] In this embodiment, as will be discussed in more detail below, the porous body 620 has a first side face 650 opposite to a second side face 660, and a third side face 670 opposite to a fourth side face 680.

[0244] The porous body 620 includes a plurality of pores. The plurality of pores are interconnected to provide a fluid path of the liquid aerosol forming substrate through the porous body 620 from the liquid absorption surface 630 to the heating surface 640. The porous body 620 is formed of a material that does not chemically interact with the liquid aerosol forming substrate. In this embodiment, the porous body 620 is a porous ceramic body and can be formed of, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2). In another embodiment, the porous body 620 may be, for example, a porous glass body.

[0245] The heating element 610 is located on the heating surface 640 of the porous body 620. In the embodiment of FIG. 8, the heating element 610 is an elongated porous film extending in a meandering pattern across the heating surface 640.

[0246] The liquid absorption surface 630 of the porous body 620 has an area different from the area of the heating surface 640 of the porous body 620. Specifically, in the embodiment of FIG. 8, the area of the heating surface 640 is smaller than the area of the liquid absorption surface 630.

[0247] In the embodiment of FIG. 8, since the width of the heating surface 640 is smaller than the width of the liquid absorption surface 630 and the length of the heating surface 640 is shorter than the length of the liquid absorption surface 630, the heating surface 640 has an area smaller than the liquid absorption surface 630.

[0248] In the embodiment of FIG. 8, the porous body 620 is shaped as a truncated pyramid. With the porous body 620 having a truncated pyramid shape, both the first side surface 650 and the second side surface 660 have a trapezoidal shape, both the third side surface 670 and the fourth side surface 680 have a trapezoidal shape, and both the liquid absorption surface 630 and the heating surface 640 have a rectangular shape. In another embodiment, the liquid absorption surface 630 and the heating surface 640 may have a square shape.

[0249] The porous body 620 tapers from the liquid absorption surface 630 toward the heating surface 640. In other words, the cross-sectional area of the porous body 620 gradually decreases from the liquid absorption surface 630 toward the heating surface 640. In the embodiment of FIG. 8, both the length and the width of the porous body 620 decrease and taper from the liquid absorption surface 630 toward the heating surface 640.

[0250] The heater assembly 600 includes a heat insulation layer 690.

[0251] The heating element 610 is disposed along the outer surface of the heat insulation layer 690. The heating element 610 is in direct contact with the heat insulation layer 690.

[0252] The heat insulation layer 690 is disposed to enhance the heat insulation between the heating element 610 and the porous ceramic body 620. The heat insulation layer 690 extends over at least a portion of the heating element 610 and is disposed to insulate the heating element 610 from the porous ceramic body 620. The heat insulation layer 690 is configured to reduce heat dissipation through the porous ceramic body 620 in order to improve energy efficiency by reducing energy loss.

[0253] The heat insulation layer 690 is planar. The heat insulation layer 690 has a size and shape configured to extend over the electric heating element 690. The heat insulation layer 690 is configured to completely extend over the surface of the heating element 610. The heat insulation layer 690 is configured to substantially cover the porous ceramic body 620 below the heat insulation layer 690.

[0254] The thermal insulation layer 690 has a first end face and an opposing second end face. The first end face is a liquid absorption surface, and the second end face is a heating surface. In this embodiment, both the liquid absorption surface and the heating surface are substantially flat surfaces. The liquid absorption surface of the thermal insulation layer 690 is in direct contact with the porous ceramic body 620. The heating surface of the thermal insulation layer 690 is in direct contact with the heating element 610.

[0255] The thermal insulation layer 690 has a thickness defined between its liquid absorption surface and its heating surface. The thickness of the thermal insulation layer 690 is less than the thickness of the porous ceramic body 620. The thermal insulation layer may have a thickness of 0.1 mm to 2 mm, preferably 0.5 mm to 1.5 mm.

[0256] The thermal insulation layer 690 contains a material having a low thermal conductivity. The thermal insulation layer 690 contains, or consists of, a material having a lower thermal conductivity than the porous ceramic body 620. The thermal insulation layer 690 may have a higher porosity than the porous ceramic body 620. The thermal insulation layer 690 may contain one or more materials such as alumina, zirconia, zirconia containing magnesium oxide, glass ceramic, quartz, and porous polymer. It will be understood that the thermal insulation layer 690 may have different shapes or contain different materials.

[0257] Referring to Figures 9(a), 9(b), and 9(c), schematic diagrams of different heating elements for an aerosol generation system are shown. Each heating element 710 comprises multiple tracks or track sections 717 electrically arranged in parallel. By being electrically arranged in parallel, the current flow is divided into separate parallel channels. The channels are then recombined.

[0258] In the heating elements of Figures 9(a) to 9(c), each heating element 710 includes a first connection pad 713 and a second connection pad 714. The first connection pad 713 and the second connection pad 714 are configured to allow connection to an external circuit. An opening or a number of openings 715 within the heating element 710 separates each track 717. Each heating element 710 includes a branching section where the current is split from the first connection pad 713 to the track 717 which defines an electrically parallel path. Each heating element 710 includes a merging section where the current is combined from the track 717 which defines an electrically parallel path into the second connection pad 714.

[0259] Various different arrangements of electrically arranged tracks or track sections are possible. In Figure 9(a), four tracks 717 are separated by three openings 715 to define four electrically parallel paths. In Figure 9(b), six track sections 717 are separated by one opening 715 to define two electrically parallel paths. In Figure 9(b), each electrically parallel path defines a meandering path between a first connection pad 713 and a second connection pad 714. In Figure 9(c), eight track sections 717 are separated by four openings 715 to define four pairs of electrically parallel paths. Each pair of electrically parallel paths in Figure 9(c) is separated by an intermediate connection 716, three of which are shown in Figure 9(c).

[0260] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and can still flow through the heating element 710, i.e., the electrical connection between the first connecting pad 713 and the second connecting pad 714 is not broken. This has the advantage of increasing the number of times the heater can be sucked up before it completely fails, potentially extending the heater's lifespan to the lifespan of the device. In contrast, in a simple meandering heater that defines a single electrical path between the first connecting pad 713 and the second connecting pad 714, if a part of the meandering heating element is damaged, the heating element will stop working due to the increased local resistance at the point of failure or fault. A fault in a simple meandering heater causes an increase in local resistance. An increase in local resistance causes an increase in power dissipation. The increase in power loss then increases the resistance until failure occurs.

[0261] The inventors also identified that parallel tracks or track sections, electrically arranged in parallel as described with reference to Figures 9(a)-(c), have a surprising additional advantage. In such arrangements, if one track section fails, the heating element 710 can still operate and operate in a favorable manner, as the failure of one track or track section results in a higher energy density for the remaining tracks or track sections during the initial transition period. In such cases, the same power is still provided, but throughput is increased over a smaller area. Such failures, which cause an increase in current on the undamaged tracks or track sections, may ultimately degrade the user experience, but the device or cartridge may include a mechanism to warn the user about the potential for future degradation of the heater assembly's optimal performance.

[0262] These mechanisms depend on the following principles. The total electrical resistance of the heating element depends on the following factors: 1) Number of parallel heating tracks (more parallel tracks reduce total resistance), 2) The cross-sectional area (width or thickness (or width and thickness)) of the parallel heating tracks (higher cross-sectional area leads to lower resistance), 3) The length of the parallel heating tracks (longer tracks have higher resistance), 4) If the heating element is porous, adjust the porosity of the heating element (the higher the porosity, the greater the resistance). 5) A specific chemical or material composition (e.g., an alloy with doping).

[0263] The overall total heating resistance R of an arrangement of multiple heating tracks or track sections (i) arranged in parallel such that the current flows in the same direction in at least two adjacent tracks or track sections. tot As shown in Equation 1, R i Defined by, [Formula 1] In the formula JPEG2026513181000002.jpg1999, n is the total number of electrically connected heating tracks in parallel.

[0264] The behavior of the parallel track heating element 710 when one heating track fails can be considered, for example, by referring to a heating element 710 having four parallel heating tracks, as shown in Figure 9(a). Each heating track has a resistance of 3 ohms. The total resistance of the heating element is 0.75 ohms, which is calculated using Equation 1.

[0265] When one heating track begins to fail, the resistance of the failed heating track increases. The total resistance of the heating element 710 also begins to increase, after a linear relationship with the resistance of the failed heating track. However, as the heating track resistance continues to increase, the resistance of the heating element 710 approaches a constant resistance value. At this constant resistance value, the effect of the failed heating track on the resistance of the heating element is negligible. In this embodiment, where each undamaged heating track has a resistance of 3 ohms, if the damaged track can be considered an open circuit (i.e., no more current can flow through it), the total resistance of the heating element eventually approaches 1 ohm. When one track fails in this embodiment, only three tracks remain to calculate the total resistance of the heating element.

[0266] To account for the behavior of such a heating element 710, a supply voltage of 3.5 volts and a target power of 5.5 watts are considered. In this example, the parallel heating tracks that are not damaged remain at an initial resistance of 3 ohms. In a failed track, as the resistance increases, the total maximum current decreases. In a failed track, when it breaks, the current decreases to zero. The current passing through the undamaged parallel tracks remains substantially constant as the resistance of the failed track increases (when the resistance change due to temperature rise is ignored).

[0267] Similar behavior is observed for maximum heating power generation. When a heating track fails, the total power generated decreases. However, in this embodiment, the maximum power remains higher than the target of 5.5 watts even if one of the heating tracks fails.

[0268] In contrast to the porous heater film, the increase in the overall heater resistance of the parallel track heating element 710 can be monitored by the control electronic circuit. In the heater film, the current density (perpendicular to the current flow) at both ends of the heater film increases in the damaged area, generating more power and raising the local temperature. Therefore, the damaged area can spread over time and a failure occurs. As a result, the resistance of the heater film increases locally, the temperature further rises and it breaks (i.e., positive feedback). In the parallel track heating element 710, in contrast, the increase in the overall heater resistance can be monitored by the control electronic circuit. The device or system may be configured to communicate to the user through the user interface that the heater assembly should be replaced when a predetermined threshold is reached.

[0269] An aerosol generator or system may include a control circuit. The control circuit may be configured to adjust the power supplied to the heater after detecting a failure in a heating track, for example, by a feedback loop. The control circuit may be configured to control the power supplied to the heater by providing a pulse-width modulation ("PWM") signal. The control circuit may adjust the power supplied to the heater by adjusting the load cycle of the pulse-width modulation signal. In one embodiment, the control circuit may be configured to have a load cycle of 33.7 percent when the heating tracks are in normal condition. The load cycle may increase to 44.9 percent when one of the heating tracks fails. When one of the heating tracks fails, the power density (heating power generated by the surface area) increases, improving the thermal efficiency of the heater body. Thus, the proper operation of the heater is not jeopardized by one failed heating track. A similar result occurs when a second heating track fails. The control circuit may be configured to further increase the load cycle (to 67.4 percent in the current embodiment). Therefore, the heating element 710, which has four parallel heating tracks, can operate under nominal conditions of 5.5 watts even if two of these heating tracks fail, because the load cycle remains below 100 percent.

[0270] The control circuit may be configured to evaluate the condition of the heating element (i.e., the number of failed heating tracks) based on the change in the nominal total resistance of the heating element 710 when a parallel heating track fails. The control circuit may also be configured to inform the user that the device should replace the heater assembly after a predetermined number of heating tracks have failed.

[0271] Referring to Figures 10(a) and 10(b), schematic diagrams of the current flow 709 around the corners of the heating element track are shown.

[0272] Figure 10(a) is a schematic diagram of current flow 709 around a well-known heating element, where the track portion defines a path with a bend, and the inner end of the bend has a sharp corner. In such a track, the current flow indicated by arrow 709 following the path of least resistance is concentrated (i.e., the current density increases). This concentration occurs at the inner edge of the corner. Current concentration can increase the local temperature, which can lead to the formation of a hot spot at the corner. Hot spots are undesirable because they can affect the efficiency and reliability of the heating element. Hot spots occur despite the fact that the local resistivity of the heater track material may increase due to the local increase in temperature (directing the current to flow through the path of lower resistance).

[0273] Figure 10(b) is a schematic diagram of the current flow 709 around the heating element 710, where the track portion 717 defines a path with bends, and the inner edge of the bends is curved. In such a track 717, the current flow 709 does not form localized hot spots.

[0274] In contrast to the track shape shown in Figure 10(a), the current flow 709 in a smoother, curved section of the track 717, as shown in Figure 10(b), remains more evenly distributed across the heating track 717, as indicated by the dashed arrow 709. The current flow 709 is induced to flow more evenly to avoid current concentration at specific points. This limits the generation of hot spots. The heating track 717 may have a resistivity gradient perpendicular to the current flow at the corner, such that the resistivity is higher in the inner part of the corner and lower in the outer part of the corner. Such a gradient is beneficial in offsetting localized high current densities and reducing the generation of hot spots.

[0275] Figure 11 is a schematic diagram of the interior of an aerosol generating system 800 according to an embodiment of the present disclosure. The aerosol generating system 800 comprises two main components: a cartridge 801 and a main body or aerosol generating device 900. The cartridge 801 is detachably connected to the aerosol generating device 900. In this embodiment, the aerosol generating device 900 comprises a device housing 901 containing a power source in the form of a battery 902, which is a rechargeable lithium-ion battery, and a control circuit 903. The aerosol generating system 800 is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece is located at the mouth end of the cartridge 801.

[0276] The cartridge 801 comprises a cartridge housing 802 that houses a heater assembly 100 and a liquid storage section or liquid storage portion 803 for holding a liquid aerosol forming substrate. The liquid aerosol forming substrate is conveyed downward from the liquid absorption surface 130 through the porous material to the heating element, and the vaporized aerosol forming substrate is released from the heating surface 140 when power is supplied to the heating element.

[0277] The cartridge 801 includes one or more air intake ports 804 formed within the cartridge housing 805 at positions along the length of the cartridge 801. The aerosol outlet 806 is located within the mouthpiece at the mouth end of the cartridge 801. The one or more air intake ports 804 are in fluid communication with the aerosol outlet 806 to define the airflow path through the cartridge 801 of the aerosol generating system 800. The airflow path flows from the one or more air intake ports 804 to the heater assembly 100 in the airflow channel. The heater assembly 100 is arranged to be in fluid communication with the airflow path in the airflow channel. Air enters the one or more air intake ports 804 and flows through the airflow channel, passing through the heater assembly 100 in the mean airflow direction.

[0278] In the embodiment shown in Figure 10, the liquid storage section 803 has an annular cross-section and is arranged around a centrally sealed aerosol channel 807. When the airflow path reaches the heater assembly 100, the airflow is redirected upward around the side of the heater assembly 100 and flows through the aerosol channel 807 to the aerosol outlet 806.

[0279] The aerosol generating system 800 is configured so that a user can inhale or smoke the mouthpiece of a cartridge, thereby drawing an aerosol into their mouth through an aerosol outlet 806. During operation, when a user smokes the mouthpiece, air is drawn out through one or more air intake ports 804, along an airflow path through an airflow channel, through and around the heater assembly 100, and then drawn out along an airflow path through an aerosol channel 807 to the aerosol outlet 806. The control circuit 903 controls the supply of power from the battery 902 to the cartridge 801 when the system is started. This then controls the amount and characteristics of the vapor produced by the heater assembly 100. The control circuit 903 includes an airflow sensor (not shown) that supplies power to the heater assembly 100 when a user is detected by the airflow sensor. This type of control device is well established in aerosol generating systems such as inhalers and e-cigarettes. When the user inhales vapor from the mouthpiece of cartridge 801, the heater assembly 100 is activated, generating vapor, which is carried into the airflow path. The vapor cools within the airflow path, forming an aerosol, which is then inhaled into the user's mouth through the aerosol outlet 806.

[0280] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc., are understood to be modified in all cases by the term “approximately.” Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein. Thus, in this context, number A is understood as A ± 10 percent (10%). In this context, number A may be considered to include a numerical value within the general standard error of the measurement of the characteristic modified by number A. In some cases used in the appended claims, number A may deviate by the percentages listed above, provided that the amount of deviation of A does not substantially affect the fundamental and novel characteristics of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points and any intermediate ranges within them, which may or may not be specifically listed herein.

Claims

1. A heater assembly for an aerosol generation system, A heat-generating element for vaporizing the liquid aerosol-forming substrate, A porous body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous body has a liquid absorption surface and a heating surface. The heating element is located on the heated surface of the porous body, The liquid-absorbing surface of the porous body has an area different from the area of ​​the heating surface of the porous body. A heater assembly comprising a porous body which includes a porous ceramic body or a porous glass body.

2. The heater assembly according to claim 1, wherein the area of ​​the heating surface of the porous body is smaller than the area of ​​the liquid-absorbing surface of the porous body.

3. The heater assembly according to claim 1 or 2, wherein the ratio of the area of ​​the heating surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is 0.9 or less.

4. The heater assembly according to any one of claims 1 to 3, wherein the ratio of the area of ​​the heating surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is at least 0.

1.

5. The heater assembly according to any one of claims 1 to 4, wherein the ratio of the area of ​​the heating surface of the porous body to the area of ​​the liquid-absorbing surface of the porous body is 0.1 to 0.

9.

6. The heater assembly according to any one of claims 1 to 5, wherein the heating surface of the porous body has a width smaller than the width of the liquid-absorbing surface of the porous body.

7. The heater assembly according to any one of claims 1 to 6, wherein the porous body has a shape that tapers from the liquid-absorbing surface of the porous body toward the heating surface of the porous body.

8. The heater assembly according to claim 1, wherein the area of ​​the liquid-absorbing surface of the porous body is smaller than the area of ​​the heating surface of the porous body.

9. The heater assembly according to any one of claims 8, wherein the liquid-absorbing surface of the porous body has a width smaller than the width of the heating surface of the porous body.

10. The heater assembly according to claim 8 or claim 9, wherein the porous body includes a shape that tapers from the heating surface of the porous body toward the liquid-absorbing surface of the porous body.

11. The heater assembly according to any one of claims 1 to 10, wherein the heating surface of the porous body is convex in one or both of the first transverse direction and the second transverse direction, and the first transverse direction is perpendicular to the second transverse direction.

12. The heater assembly according to any one of claims 1 to 11, wherein the average pore diameter of the porous body changes between the liquid absorption surface and the heating surface.

13. The porous body has a heating end and a liquid absorption end, the heating surface is located at the heating end, and the liquid absorption surface is located at the liquid absorption end. The heater assembly according to claim 12, wherein the porous body has a first average pore diameter at the liquid absorption end and a second average pore diameter at the heating end, and the first average pore diameter is larger than the second average pore diameter.

14. A cartridge for an aerosol generation system, A heater assembly according to any one of claims 1 to 13, A cartridge comprising a liquid storage portion for holding a liquid aerosol-forming substrate, the liquid storage portion being disposed on the liquid-absorbing surface of the porous body.

15. Aerosol generation system, The cartridge according to claim 14, Aerosol generator, A power supply for supplying power to the heating element, and an aerosol generating system comprising an aerosol generating device having a control circuit configured to control the supply of power from the power source to the heating element, and an aerosol generating system.

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