Two-part heater assembly

Abstract

This disclosure relates to a heater assembly (100) for an aerosol generating system, comprising a heating element (110) for vaporizing a liquid aerosol forming substrate and a porous ceramic body (130) for transporting the liquid aerosol forming substrate to the heating element (110), wherein the porous ceramic body (130) has a liquid absorption surface (134) and a heating surface (133), and the heating element (110) is located on and coupled to the heating surface (133) of the porous ceramic body (130).

Description

Technical Field

[0001] The present disclosure relates to a heater assembly for an aerosol generation system. 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 and delivering the aerosol into a user's mouth. The present disclosure further relates to a cartridge and an aerosol generation system comprising the heater assembly, and also to a method of manufacturing the heater assembly.

Background Art

[0002] Aerosol generation systems for heating a liquid aerosol forming substrate to generate an aerosol to be delivered to a user are generally known in the prior art. These systems typically comprise an aerosol generator and a replaceable cartridge. The cartridge 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 the cartridge also includes a mouthpiece. When the user sucks on 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. Thereby, a volatile compound is released from the liquid aerosol forming substrate and cooled to form an aerosol. The aerosol is then inhaled into the user's mouth through the mouthpiece.

[0003] In some other known aerosol generating systems, the aerosol generating system comprises a heater assembly having a resistance heating element located on the heated surface of a porous body. The liquid aerosol-forming substrate is supplied to the heating element from the liquid storage section through the pores of the porous body by capillary action. 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 encountered by such known aerosol generating systems is "dry heating" or "dry puffing," which occurs when the heating element is heated with insufficient liquid aerosol-forming substrate supplied to it. This can occur, for example, when the user consumes all the liquid aerosol-forming substrate in a cartridge and the cartridge is depleted and needs to be replaced. During operation, it is preferable to maintain a supply of the liquid aerosol-forming substrate to the heating element so that the heating element remains moist, as this helps ensure that a satisfactory aerosol is generated when negative pressure is applied to the mouthpiece. Air heating can lead to overheating of the heating element and potentially to thermal decomposition of the liquid aerosol-forming substrate, which may result in the generation of undesirable byproducts and, furthermore, unsatisfactory aerosols. Allowing the aerosol generation system to continue operating when the liquid aerosol-forming substrate is not supplied to the heating element may degrade the quality of the user experience.

[0004] Numerous prior art documents disclose aerosol generating systems having a porous transport element and a separate heating element, both of which are assembled within the aerosol generating system such that the heating element, powered through electrical contacts, heats the porous transport element. Such known systems are difficult to manufacture and assemble while maintaining consistent manufacturing tolerances, and therefore may result in inconsistent vapor generation and flavor development. Inconsistent manufacturing tolerances can also affect heat conduction from the heating element to the porous transport element, reducing the energy efficiency of such systems. The liquid is supplied from the liquid storage section to the heating element through pores in the transport element. These known aerosol generating systems may also experience "dry heating" or "dry puffing," and therefore have associated drawbacks, namely undesirable by-products, unsatisfactory aerosols, and a poor user experience.

[0005] It is desirable to provide heater assemblies that are easier to manufacture and assemble with greater reliability, and therefore more energy-efficient, resulting in more consistent aerosol generation. It is also desirable to provide heater assemblies that reduce the likelihood of the user experiencing air heating or dry puffing. [Overview of the Initiative]

[0006] This disclosure relates to a heater assembly for an aerosol generating system. The heater assembly may include a heating element for vaporizing a liquid aerosol-forming substrate. The heater assembly may also include a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body may have a liquid-absorbing surface and a heating surface. The heating element may be located on and bonded to the heating surface of the porous ceramic body.

[0007] According to the present invention, a heater assembly for an aerosol generation system is provided. The heater assembly comprises a heating element for vaporizing a liquid aerosol-forming substrate. The heater assembly comprises a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body has a liquid-absorbing surface and a heating surface. The heating element is located on and bonded to the heating surface of the porous ceramic body.

[0008] 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.

[0009] As used herein, the term "aerosol generating cartridge" refers to a component that interacts with a liquid aerosol generating apparatus in order to generate an aerosol. The aerosol generating cartridge contains, or is configured to contain, a liquid aerosol generating substrate.

[0010] As used herein, the term "aerosol-forming substrate" refers to a substrate having the ability to release volatile compounds that can form aerosols. Such volatile compounds may be released by heating the aerosol-forming substrate.

[0011] As used herein, the term "heating element" refers to a component that transfers thermal energy to a liquid aerosol generating substrate. It is understood that an electrically heated element may be placed directly on a porous material.

[0012] As used herein, the term “porous material” refers to a component having multiple pores, at least some of which are interconnected. A porous material is configured to contain a liquid within its multiple pores.

[0013] 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 by conduction, convection, or radiation than a more thermally insulating component.

[0014] The heater assembly of the present invention provides an improved component for an aerosol generating system. By providing a heater assembly in which a heating element is located on the heated surface of a porous ceramic body and bonded to it, a more robust and reliable connection can be established between the heating element and the porous ceramic body. This can advantageously help to improve heat transfer between the heating element and the porous ceramic body.

[0015] The bonding of the heating element to the heating surface of the porous ceramic body also offers the advantage of providing a more reliable and easier-to-assemble heater assembly, and therefore a more energy-efficient heater assembly that can generate a more consistent aerosol. This can provide users of the aerosol generating system with an improved and more enjoyable experience. Such arrangements can also help reduce the likelihood of users experiencing dry heating or dry puffing.

[0016] The advantage of mounting and bonding the heating element to the heating surface of the porous ceramic body is that it helps mitigate manufacturing tolerance issues encountered with wick heaters, coil heaters, and other configurations where the heating element is detached from the liquid transport element. The dimensions and placement of the electric heating element relative to the porous body are also fixed, which helps in more consistent aerosol production. This is because the electric heating element is fixed to the porous ceramic body, which helps in supplying the heating element with a liquid aerosol-forming substrate. This also helps prevent undesirable heat loss, which contributes to improved energy efficiency.

[0017] By mounting and bonding a heating element to the heated surface of a porous ceramic body, the resulting aerosol generation system can benefit from reduced material requirements. This is because the need for intermediate components to fix the heating element to the porous body can be reduced or completely eliminated. Material savings can lead to cost reductions for the entire aerosol generation system. A further advantage of reduced material requirements in the overall aerosol generation system is the provision of a more sustainable and environmentally friendly solution.

[0018] The heating element may be fluid permeable.

[0019] As used herein, the term “fluid permeability” in the context of a heating element means that a liquid aerosol-forming substrate can pass from one side of the heating element to the other side without having to travel around the heating element.

[0020] Naturally, if the heating element is fluid-permeable, the material from which the heating element is fabricated may also be fluid-permeable. Alternatively, the material from which the heating element is fabricated may be fluid-impermeable, but nevertheless, the structure or arrangement of the heating element may allow a liquid aerosol-forming substrate to pass from one side of the heating element to the other.

[0021] The heating element may be an electrically heated element. For example, the heating element may be a resistance heating element. The heating element may have any preferred shape or form. Examples of preferred shapes and forms, but are not limited to, include strips, flakes, filaments, wires, meshes, flat spiral coils, fibers, or cloths.

[0022] In some preferred examples, the heating element is planar. A planar heating element may extend substantially within a plane.

[0023] In some preferred examples, the heating element comprises a mesh. The heating element may comprise an array of filaments forming a mesh. As used herein, the term "mesh" means

[0024] This includes grids and arrays of filaments with spaces in between. The term mesh also includes woven and nonwoven fabrics.

[0025] The filaments may be formed by etching a sheet material such as foil. This can be particularly advantageous when the heater assembly comprises an array of parallel filaments.

[0026] If the heating element comprises a mesh or fabric of filaments, the filaments may be formed individually or knitted together.

[0027] The heating element may include an electrically resistive heating element. The heating element may be made of any suitable conductive material. Suitable materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped ceramics or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of 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 (registered trademark), iron-aluminum-based alloys, and iron-manganese-aluminum-based alloys. Timetal (registered trademark) is a registered trademark of Titanium Metals Corporation. The heating element may be made of stainless steel, such as 300 series stainless steel like AISI 304, 316, 304L, 316L, etc. In a preferred example, the electric heating element may include one or more of NiCr and TiZr.

[0028] Additionally, the heating element may include a combination of the above materials. A combination of materials may be used to improve the control of the resistance of the heating element. For example, a material with a high resistivity may be combined with a material with a low resistivity. This can be advantageous when one of the materials is more beneficial from other perspectives, such as cost, machinability, or other physical and chemical parameters. Advantageously, heating at high resistance allows for more efficient use of battery energy.

[0029] The porous ceramic body may include a porous material having open voids. Multiple open voids may be interconnected to provide a fluid pathway for the aerosol-generating liquid through the porous ceramic body. The porous ceramic body may include a material that does not chemically interact with the liquid aerosol-forming substrate. The porous material may have a porosity of 20 percent to 80 percent. The porous ceramic body may have a flat surface or a curved surface. The porous ceramic body may have a geometric shape. The porous ceramic body may have a cubic or rectangular parallelepiped shape, or a disc or cylindrical shape, or any combination thereof. The porous ceramic body may include or consist of a material having low thermal conductivity. The porous ceramic body may include or consist of a non-conductive material. The porous ceramic body may include a polymer material or a ceramic material. The porous ceramic body may include cotton. The porous ceramic body may include, but is not limited to, porous ceramics such as Al2O3, ZrO2, Si3N4, SiC, Ti3AlC2, BN, AlN, SiO2, MgO, mica, diatomaceous earth, silicates, silicides, borides, glass, or any combination thereof. The porous ceramic body may also include aluminum nitride or silicon carbide. Aluminum nitride and silicon carbide typically have relatively high thermal conductivity of about 100–200 watts / meter Kelvin. In sintered form, aluminum nitride and silicon carbide can have thermal conductivity of less than 100 watts / meter Kelvin. The porous ceramic body may have any thickness. The thickness of the porous ceramic body may refer to the extension of the porous ceramic body in the direction between the liquid absorption surface and the heating surface. This may correspond to the direction of the liquid flow path through the porous ceramic body. The thickness of the porous ceramic body may depend on the material from which it is fabricated and the thermal properties of the liquid it contains. The porous ceramic body may have a thickness of at least 1 millimeter. For example, the porous ceramic body may have a thickness of at least 2 millimeters, at least 3 millimeters, at least 4 millimeters, or at least 5 millimeters.

[0030] The porous ceramic body may have a thickness of 10 millimeters or less. For example, the porous ceramic body may have a thickness of 9 millimeters or less, 8 millimeters or less, 7 millimeters or less, or 6 millimeters or less.

[0031] The porous ceramic body may have a thickness of 1 millimeter to 10 millimeters. For example, the porous ceramic body may have a thickness of 2 millimeters to 9 millimeters, 3 millimeters to 8 millimeters, 4 millimeters to 7 millimeters, or 5 millimeters to 6 millimeters. The porous ceramic body may have a thickness of about 5 millimeters.

[0032] The heating element may have any thickness. The thickness of the heating element may refer to the extension of the heating element in the direction between the liquid absorption surface and the heating surface. This may correspond to the direction of the liquid flow path through the porous ceramic body. The heating element may have a thickness of at least 1 micrometer. The heating element may have a thickness of at least 2 micrometers. The heating element may have a thickness of at least 5 micrometers. The heating element may have a thickness of at least 200 micrometers. The heating element may have a thickness of at least 220 micrometers.

[0033] The heating element may have a thickness of less than at least 300 micrometers. The heating element may have a thickness of less than at least 250 micrometers. The heating element may have a thickness of less than at least 50 micrometers. The heating element may have a thickness of less than at least 20 micrometers.

[0034] The heating element may have a thickness of 1 millimeter to 10 millimeters. The heating element may have a thickness of 1 millimeter to 5 millimeters. The heating element may have a thickness of 2 millimeters to 5 millimeters.

[0035] I The heating element may have a thickness of 200 to 300 micrometers. The heating element may have a thickness of 200 to 250 micrometers. The heating element may have a thickness of 220 to 300 micrometers.

[0036] According to one embodiment of the present disclosure, a cartridge is provided. The cartridge may comprise a heater assembly. The cartridge may comprise 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 ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body may have a liquid-absorbing surface and a heating surface. The heating element may be located on and bonded to the heating surface of the porous ceramic body.

[0037] According to one embodiment of the present disclosure, a cartridge is provided, comprising a heater assembly and a liquid storage portion for holding a liquid aerosol-forming substrate, the heater assembly comprising a heating element for vaporizing the liquid aerosol-forming substrate and a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body has a liquid-absorbing surface and a heating surface. The heating element is located on and bonded to the heating surface of the porous ceramic body.

[0038] The cartridge may be equipped with a liquid aerosol-forming substrate in the liquid storage portion. The liquid aerosol-forming substrate may be as described above.

[0039] The porous body may be fluid-connected to the liquid storage portion. The porous body may have a liquid-absorbing surface. The liquid-absorbing surface of the porous ceramic body may be fluid-connected to the liquid storage portion.

[0040] The liquid storage portion may be disposed on the liquid-absorbing surface of the porous ceramic body.

[0041] An aerosol generating system is provided. The aerosol generating system may comprise a cartridge and an aerosol generating device. The cartridge may comprise a heater assembly. The cartridge may comprise 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 ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body may have a liquid-absorbing surface and a heating surface. The heating element may be located on and bonded to the heating surface of the porous ceramic body.

[0042] The aerosol generator may be equipped with a power supply for providing power to the heating element. The aerosol generator may be equipped with a control circuit configured to control the supply of power from the power supply to the heating element.

[0043] An aerosol generation system is provided, comprising a cartridge and an aerosol generator, wherein the cartridge comprises a heater assembly and a liquid storage section 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 ceramic body for transporting the liquid aerosol-forming substrate to the heating element. The porous ceramic body has a liquid absorption surface and a heating surface. The heating element is located on and coupled to the heating surface of the porous ceramic body.

[0044] The aerosol generator may include 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.

[0045] The cartridge may be equipped with a liquid aerosol-forming substrate in the liquid storage portion. The liquid aerosol-forming substrate may be as described above.

[0046] The aerosol generating system may be portable. The aerosol generating system may be comparable in size to a conventional cigar or cigarette.

[0047] The cartridge may be detachably coupled to the aerosol generator.

[0048] 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.

[0049] 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.

[0050] 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%.

[0051] 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 path or aerosol channel, and the airflow path may extend through the internal passage or aerosol channel of the liquid storage portion.

[0052] 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 the Tritan trademark made from three monomers, namely dimethyl terephthalate (DMT), cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). The cartridge housing may define a portion of the liquid storage area, i.e., a storage section. The cartridge housing may define a 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The control circuit may include any suitable controller or electrical component. The controller may include memory. Information for performing the operation of the device or system 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, 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).

[0058] Features described in relation to one of the above embodiments may be equally applicable to other embodiments of the present disclosure.

[0059] The heating element may be in contact with the heating surface of the porous ceramic body, and the heating element and the heating surface of the porous ceramic body are bonded by this contact. The heating element may be in contact with the entire heating surface of the porous ceramic body. Alternatively, the heating element may be in contact with only a portion of the heating surface of the porous ceramic body. The heating element may be in direct contact with the heating surface of the porous ceramic body. Alternatively, the heating element may be indirectly in contact with the surface of the porous ceramic body. Contact between the heating element and the heating surface of the porous ceramic body can further improve the robustness and reliability of the connection between the heating element and the porous ceramic body. This can be advantageous as it can help improve heat transfer between the heating element and the porous ceramic body. This also helps prevent undesirable heat loss, which can improve energy efficiency and also contribute to the generation of more consistent aerosols. This further provides users of the aerosol generating system with an improved and more enjoyable experience. Such arrangements can also help reduce the likelihood of users experiencing dry heating or dry puffing.

[0060] The heating element and the heating surface of the porous ceramic body may be bonded by an intervening layer located between the heating element and the heating surface of the porous ceramic body. The intervening layer may cover the entire heating surface of the porous ceramic body. Alternatively, the intervening layer may cover only a portion of the heating surface of the porous ceramic body. The intervening layer may be an adhesive. The intervening layer may be in direct contact with one or both of the heating surface of the porous ceramic body and the heating element. Advantageously, the intervening layer may help to bond the heating element more firmly to the heating surface of the porous ceramic body. The intervening layer may also provide favorable heat transfer properties between the heating element and the surface of the porous ceramic body. This may further improve the consistency of the generated aerosol and further improve the user experience of the aerosol generating system.

[0061] The heating element may be a porous ceramic heating element. The heating element may be porous across its entire surface. Alternatively, the heating element may not be porous across its entire surface. For example, the first part of the heating element may be porous, and the second part may be non-porous. Embodiments in which the heating element is a porous ceramic heating element may be advantageous in that the aerosol-generating liquid can flow from the porous ceramic body into the heating element. This may improve the energy efficiency of aerosol generation and may also contribute to more consistent aerosol generation.

[0062] The heating element may be a doped ceramic material. The heating element may be doped to make it conductive. Doping the ceramic material may be advantageous in that it avoids changing the porosity of the ceramic material when it is a porous ceramic material. This may be preferred over other known techniques for forming heating elements, which involve depositing the heating element by thin-film or thick-film techniques, which can reduce the properties of the ceramic material, particularly the porosity. The thickness of the doped portion may be increased when the cross-sectional area of ​​the heating portion is small or when the required heating resistance is high. The dopant used to dope the ceramic heating element 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 heating portion and the porous portion may include a portion of the partially doped ceramic material. In other words, the edge of the interface adjacent to the heating portion may be doped to substantially the same extent as the heating portion, and the edge of the interface adjacent to the porous portion may not be substantially doped.

[0063] Ceramic materials may be doped by ion implantation. Ion implantation involves implanting or exchanging ions into a layer of bulk material, removing one species and replacing it with another. Ion implantation can be carried out chemically or physically.

[0064] Ceramic materials may be doped by nuclear transmutation. Nuclear transmutation involves irradiating a material with particles such as neutrons or alpha particles to convert one atomic species already present in the material into another, resulting in a short-lived decay process that leads to a stable isotope that was not present in the original material. Nuclear transmutation has the advantage that doping occurs directly within the ceramic material and does not require the bonding or attachment of additional conductive materials. Therefore, nuclear transmutation offers a more monolithic approach.

[0065] The heating element may be a metal heating element, such as a metal heating track. This may be advantageous in that the heating element can be pre-formed, the porous ceramic body formed, and the heating element can be bonded to the heating element simultaneously. This may also help simplify the manufacturing of the heater assembly by reducing manufacturing time and providing a more cost-effective solution. This is advantageous because the metal heating element can be fully or partially assembled inside the porous ceramic body, creating a tight mechanical connection between the metal heating element and the porous ceramic body.

[0066] The heating element may be deposited onto the porous ceramic body by thick-film techniques such as screen printing, inkjet printing, aerosol jet printing, or laser direct structuring. Such printing processes can be advantageous, especially when high-speed manufacturing processes are used.

[0067] The heating element may be deposited by thin-film techniques such as physical or chemical vapor deposition. This can offer several advantages, including more uniform heating of the heating element. For example, such techniques can allow for greater diversity in the design and layout of the heating element without excessively compromising the desired resistivity target of the heating element. Furthermore, these deposition techniques may result in less material being deposited within the voids of the ceramic body itself compared to, for example, thicker film deposition techniques. Therefore, the design of voids or gaps within the heating element can be more closely correlated with the design of the ceramic body.

[0068] The heating element and the porous ceramic body may be joined by molding. For example, the heating element may be pre-formed, and the porous ceramic body may be molded around the pre-formed heating element. This can also help simplify the manufacturing of the heater assembly by reducing manufacturing time and providing a more cost-effective solution. This is advantageous because the heating element can be fully or partially assembled inside the porous ceramic body, creating a tight mechanical connection between the heating element and the porous ceramic body.

[0069] The heating element and the porous ceramic body may be formed separately and assembled to form the heater assembly. This is advantageous because, prior to assembly, the two components may be manufactured by separate technologies or in separate locations, thus allowing for increased manufacturing flexibility. As a result, this may also reduce the need for specialized equipment at the assembly site, and therefore help reduce the constraints and costs associated with the manufacture of the heating element.

[0070] The liquid-absorbing surface of the porous ceramic body may have a different area than the heating surface of the porous ceramic body. The porous ceramic body may be substantially incompressible.

[0071] 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 for vaporizing the aerosol-forming substrate. Inefficient heater assemblies reduce aerosol throughput.

[0072] Advantageously, providing a porous ceramic body with different areas for the heating surface and the liquid absorption surface can improve the throughput of aerosols that can be generated by the heater assembly compared to a heater assembly where the heating surface has the same area as the liquid absorption surface.

[0073] Improving heating efficiency may reduce power consumption during use of the heater assembly.

[0074] The heating surface area of ​​the porous ceramic body may be smaller than the liquid-absorbing surface area of ​​the porous ceramic body. The liquid-absorbing surface area of ​​the porous ceramic body may be larger than the heating surface area of ​​the porous ceramic body.

[0075] Advantageously, if the porous ceramic body has a shape such that the heating surface has a smaller area than the liquid absorption surface, the heat flow from the heating element to the liquid absorption surface and then to the liquid storage portion can be reduced by conduction. The relatively small heating surface provides a small heat transfer region that can conduct heat from the heating element to the porous ceramic body and then to the liquid absorption surface.

[0076] Reducing heat loss from the heating element to the bulk of the porous ceramic body can increase heating efficiency because, as a result, more thermal energy provided by the heating element can be used to vaporize the aerosol-forming substrate. Consequently, a porous ceramic body with a shape such that the heating surface has a smaller area than the liquid-absorbing surface can increase the throughput of aerosols generated by the heater assembly.

[0077] Advantageously, a porous ceramic 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 delivered to the heating surface to vaporize. In other words, the size and shape of the heating surface can more closely match the size and shape of the heating element. As a result, more liquid aerosol-forming substrate may be delivered from the liquid absorption surface to the region of the heating surface closer to the heating element, which can result in more liquid aerosol-forming substrate vaporizing on the heating surface. An increase in vaporized liquid aerosol-forming substrate can increase the throughput of aerosols generated by the heater assembly. Furthermore, this arrangement can allow for maximization of the power density on the heating surface, which also improves heating efficiency.

[0078] Advantageously, a liquid absorption surface having a larger surface area than the heating surface may allow the liquid absorption surface to receive a greater amount of liquid aerosol substrate from the liquid storage portion. As a result of the relatively small surface area of ​​the heating surface, 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 ceramic body toward the heating surface. A higher flow rate of liquid aerosol-forming substrate in the heating element can increase the throughput of aerosols generated by the heater assembly.

[0079] The heating surface area of ​​the porous material may be larger than the liquid-absorbing surface area of ​​the porous ceramic material. The liquid-absorbing surface area of ​​the porous material may be smaller than the heating surface area of ​​the porous ceramic body.

[0080] Advantageously, if the porous ceramic body 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 cause 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 ceramic body with 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.

[0081] Advantageously, a porous ceramic body with 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 delivered to the heating surface to vaporize. 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 delivered from the liquid absorption surface to the region of the heating surface closer to the heating element, which can lead to the vaporization of more liquid aerosol-forming substrate on the heating surface. An increase in the vaporized liquid aerosol-forming substrate can increase the throughput of the aerosol generated by the heater assembly.

[0082] The heated surface of the porous ceramic body may be convex in one or both of the first and second transverse directions, the first transverse direction being perpendicular to the second transverse direction.

[0083] The inclusion of such a porous ceramic body may allow for an increase in the surface area of ​​the heated surface without increasing the width of the heated surface. This can help improve the efficiency of the aerosol generating system when vaporizing the liquid aerosol-forming substrate, while avoiding the need to redesign other components of the aerosol generating system to accommodate the porous ceramic body.

[0084] 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 produced by the aerosol-generating system.

[0085] Improving the entrainment of vapor in the airflow through an aerosol generation system can prevent or reduce the condensation of vapor into large droplets of liquid aerosol-forming substrates. This can help avoid an unpleasant and undesirable user experience.

[0086] Improving the entrainment of vapor in the airflow passing through an aerosol generating system can help avoid or reduce condensation of vapor on the internal surfaces of the aerosol generating system. This can help avoid or minimize damage to the aerosol generating system and enable its optimal functioning.

[0087] The heated surface of the porous ceramic body may be convex in a single transverse direction.

[0088] The heated surface of the porous ceramic body may be convex in both the first transverse direction and the second transverse direction.

[0089] The heating surface of the porous ceramic body 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.

[0090] The heating element may be convex in one or both of the first and second transverse directions.

[0091] 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 ceramic body 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 body 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 body in both the first and second transverse directions, respectively.

[0092] The average pore size of the porous ceramic body can vary between the liquid-absorbing surface and the heating surface.

[0093] The porous ceramic body may include a first average pore size at the liquid absorption surface and a second average pore size at the heating edge. The first average pore size may be larger than the second average pore size.

[0094] The first pore size at the liquid-absorbing surface may be about 150 micrometers. The second pore size at the heating edge may be about 20 micrometers. The pore size changes linearly between the first and second pore sizes, providing a pore size gradient between the liquid-absorbing surface and the heating edge of the porous ceramic body.

[0095] The pore structure and pore size gradient of the porous ceramic body can be achieved by etching the pores into a portion of the silicon carbide.

[0096] 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 direct contact with the heating element. Alternatively, the insulating layer may be in indirect contact with the heating element. The insulating layer may be in direct contact with the heated surface of the porous ceramic body. Alternatively, the insulating layer may be in indirect contact with the heated surface of the porous ceramic body. The insulating layer may be in direct contact with the heated surface of the porous ceramic body and the heating element, respectively. Alternatively, the insulating layer may be in indirect contact with the heated surface of the porous ceramic body and the heating element, respectively. The insulating layer may be in direct contact with one or both. The insulating layer may be configured to reduce heat transfer from the heating element to the porous ceramic body.

[0097] In this configuration, heat loss from the heating element to the porous ceramic body and the liquid within the porous ceramic body is reduced. This provides a more efficient heater assembly that can increase the amount and number of times the device is used by the user before the device power source, such as a battery, is depleted. The inventors estimated that in known devices, about one-third of the energy from the heating element is lost through conduction through the porous body and the liquid within the porous body. The remaining two-thirds are used to generate an aerosol by heating the liquid aerosol-forming substrate. In the configuration described herein, these energy losses are reduced. Specifically, the insulating layer reduces heat propagation or conduction from the heating element to or through the porous ceramic body. This reduction in conduction can concentrate heat on the heated surface of the porous ceramic body, minimize heat dissipation, and increase the heating efficiency of the heater assembly.

[0098] The insulating 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 insulating layer that is easy to manufacture while being particularly effective in reducing energy loss.

[0099] The insulating layer may include a material having a thermal conductivity of less than 40 watts / meter Kelvin. This has the advantage of providing an insulating layer that is effective in reducing energy loss through the porous ceramic body. The insulating layer may also include a material having a thermal conductivity of less than 10 watts / meter Kelvin. This has the advantage of providing an insulating layer that is particularly effective in reducing energy loss through the porous ceramic body.

[0100] The insulating layer may extend completely 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.

[0101] The insulating layer may contain one or more of the following: alumina, zirconia, zirconia with magnesium oxide, glass ceramic, quartz, and porous polymer. The porous polymer may be polyimide.

[0102] 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 is advantageous because these materials are compatible with manufacturing processes involving sintering, and heater assemblies with an insulation layer made of one of these materials are easier to manufacture.

[0103] The insulation layer may have a thickness of 0.1 mm to 2 mm. An insulation layer having this thickness is 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 mm to 1.5 mm. An insulation layer having this thickness is even more suitable for reducing energy loss from the heating element to the porous ceramic body.

[0104] The heating element may comprise multiple tracks or track sections arranged electrically 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 can be tailored to the requirements of the control electronic equipment.

[0105] At least two of the electrically parallel heating tracks may have similar resistances or identical resistances. Preferably, all electrically parallel heating tracks have similar or identical resistances. The electrically parallel heating tracks may have different resistances, which is particularly beneficial in heater assemblies where zones of the heating element are advantageous for generating 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.

[0106] 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.

[0107] 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. One or more 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 convergence portion. In the convergence portion, the current is coupled from the track portions defining electrically parallel paths to the second connection pad.

[0108] Various different arrangements of electrically parallel tracks or track sections are possible. The heating element may have two, three, four or more track sections that define electrically parallel paths.

[0109] By electrically arranging tracks or track sections in parallel, if one track section is faulty, the current can be redistributed and 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 can cause an increase in local resistance, leading to increased power consumption and potentially increasing resistance until further damage occurs.

[0110] 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 in a favorable manner 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 it is provided 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's future performance falling below optimal levels. Electrically parallel tracks have the advantage of increasing the number of fume extractions before complete heater failure, potentially extending the heater's lifespan to the end of the device's life.

[0111] 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.

[0112] The curved inner end of the bend has the advantage of guiding the current to flow more evenly around at least one bend. This reduces the current concentration and limits the generation of hot spots.

[0113] The heating element may have multiple tracks or track sections having a gradient of electrical resistivity perpendicular to the current flow at one or more corners, resulting in higher electrical resistivity on the inside of the corner and lower resistivity on the outside of the corner. Such gradients are beneficial for offsetting localized high current densities and reducing the generation of hot spots.

[0114] This disclosure also relates to a method for manufacturing a heater assembly for an aerosol generating system. The method may include forming a heating element for vaporizing a liquid aerosol-forming substrate. The method may also include forming a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element, the porous ceramic body having a liquid-absorbing surface and a heating surface. The method may include bonding the heating element to the heating surface of the porous ceramic body.

[0115] The present invention provides a method for manufacturing a heater assembly for an aerosol generating system. The method includes forming a heating element for vaporizing a liquid aerosol-forming substrate. The method includes forming a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element, the porous ceramic body having a liquid-absorbing surface and a heating surface. The method includes bonding the heating element to the heating surface of the porous ceramic body.

[0116] This method may include a step of adding a template to the heating element material. The template may be removable once the heating element is formed. This is advantageous because it may create a porous structure within the heating element, which can facilitate aerosol generation and liquid vaporization.

[0117] An aerosol generating system is provided according to one embodiment of the present disclosure. The aerosol generating system may include a heater assembly as 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 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.

[0118] 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 does not decrease to the same extent as if the mean airflow direction were directly opposite to the mean vapor discharge direction. This reduces the tendency for recirculation and turbulence to occur within the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Consequently, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0119] The average vapor emission direction may be substantially perpendicular to the heated surface of the porous ceramic body. As used herein, the term “substantially perpendicular” means 90 degrees plus or minus 10 degrees, preferably plus or minus 5 degrees.

[0120] The advantage of having the mean vapor release direction substantially perpendicular to the heating surface of the porous ceramic body is that, because the vapor is released substantially perpendicular to the heating surface of the porous ceramic body, the mean vapor release direction can be easily directed relative to the mean airflow direction. Therefore, the desired angle between the mean vapor release direction and the mean airflow direction can be achieved by appropriately angling the heater assembly with respect to the airflow in the airflow path, or vice versa.

[0121] 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 110 degrees, preferably less than 100 degrees.

[0122] 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 90 degrees. This arrangement ensures that the vapor is discharged at an angle substantially perpendicular to the mean airflow direction. The mean vapor discharge direction has no velocity or directional component opposite to the airflow direction, thus reducing momentum loss in the airflow. This reduces the tendency for recirculation and turbulence to occur within the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, vapor mixing within the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0123] The heater assemblies and airflow paths 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. Therefore, any loss of momentum in the airflow is further reduced. This reduces the tendency for recirculation and turbulence to occur within the airflow path, and the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, the mixing of vapor into the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0124] 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.

[0125] The heater assemblies and airflow paths may be arranged such that the mean vapor discharge direction and the mean airflow direction are substantially identical. In this arrangement, since the mean vapor discharge direction and the mean airflow direction are identical, 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 the vapor is less likely to collide with the internal surfaces of the aerosol generating system. Furthermore, vapor mixing in the airflow is improved. Therefore, the likelihood of aerosol condensation occurring within the aerosol generating system is low.

[0126] The cross-sectional area of ​​the airflow path in the heater assembly region 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 about 1 meter / second. It has been found that airflow velocities in this range effectively entrain the steam released from different designs of the heating element without excessively cooling the heating element.

[0127] 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 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, with a lower vapor release rate of approximately 0.1 meters / second. Such a low vapor release rate means that the vapor is easily carried by an airflow that reduces vapor collisions on the inner walls of the aerosol generating system.

[0128] The features and related advantages described above in relation to the heating element of this disclosure may also be applied to the method of this disclosure. [Examples]

[0129] A non-exclusive list of non-limiting embodiments is provided below. One or more features of these embodiments may be combined with any one or more features of other embodiments, forms, or aspects described herein.

[0130] Example 1. A heater assembly for an aerosol generation system, comprising a heating element for vaporizing a liquid aerosol-forming substrate and a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element, wherein the porous ceramic body has a liquid-absorbing surface and a heating surface, and the heating element is located on the heating surface of the porous ceramic body and is coupled thereto. Example 2. The heater assembly according to Example 1, wherein the heating element is in contact with the heating surface of the porous ceramic body, and the heating element and the heating surface of the porous ceramic body are bonded together by this contact. Example 3. The heater assembly according to Example 1, wherein the heating surface of the heating element and the heating surface of the porous ceramic body are bonded together by an intervening layer located between the heating element and the heating surface of the porous ceramic body. Example 4. A heater assembly according to any one of Examples 1 to 3, wherein the heating element is a porous ceramic heating element. Example 5. The heater assembly according to Example 4, wherein the heating element is a doped portion of a porous ceramic heating element. Example 6. A heater assembly according to any one of Examples 1 to 3, wherein the heating element is a metal heating element such as a metal heating truck. Example 7. A heater assembly according to any one of Examples 1 to 4, wherein the heating element is deposited on a porous ceramic body by a thick-film technology such as screen printing, inkjet printing, aerosol jet printing, or laser direct structuring. Example 8. The heating element is a heater assembly according to any one of Examples 1 to 4, which is deposited by thin-film technology such as physical vapor deposition or chemical vapor deposition. Example 9. A heater assembly according to any one of Examples 1 to 6, wherein the heating element and the porous ceramic body are joined by molding. Example 10. A heater assembly according to any one of Examples 1 to 6, wherein the heating element and the porous ceramic body are formed separately and assembled to form a heater assembly. Example 11. A heater assembly according to any one of Examples 1 to 10, wherein the liquid absorption surface of the porous ceramic body has a different area from the heating surface area of ​​the porous body. Example 12. A heater assembly according to any one of Examples 1 to 11, 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 13. A heater assembly according to any of Examples 1 to 12, wherein the average pore size of the porous ceramic body varies between the liquid absorption surface and the heating surface. Example 14. A heater assembly according to any one of Examples 1 to 13, further comprising an insulating layer having a lower thermal conductivity than the porous body, wherein the insulating layer is positioned between the porous body and the heating element and is in contact with each of them, and the insulating layer is configured to reduce heat transfer from the heating element to the porous body. Example 15. A heater assembly according to any one of Examples 1 to 15, wherein the heating element comprises multiple tracks or track sections, and the distance between at least two of the multiple tracks or track sections is within the range of 150 to 300 micrometers. Example 16. A method for manufacturing a heater assembly for an aerosol generating system, comprising forming a heating element for vaporizing a liquid aerosol forming substrate and forming a porous ceramic body for transporting the liquid aerosol forming substrate to the heating element, wherein the porous ceramic body has a liquid absorption surface and a heating surface, and the heating element is bonded to the heating surface of the porous ceramic body. Example 17. A method for manufacturing a heater assembly for an aerosol generating system according to Example 16, wherein the step of bonding the heating element to the heating surface of a porous ceramic body includes bonding the heating element to the heating surface of a porous ceramic body in contact with the heating element such that the heating element and the heating surface of the porous ceramic body are bonded by this contact. Example 18. A method for manufacturing a heater assembly for an aerosol generating system according to Example 16, wherein the step of bonding a heating element to the heating surface of a porous ceramic body includes bonding the heating element and the heating surface of the porous ceramic body to an intervening layer between the heating element and the heating surface of the porous ceramic body. Example 19. A method for manufacturing a heater assembly for an aerosol generating system according to any one of Examples 16 to 18, wherein the heating element is a porous ceramic heating element. Example 20. A method for manufacturing a heater assembly for an aerosol generating system according to any one of Examples 16 to 18, wherein the heating element is a metal heating element such as a metal heating truck. Example 21. A method for manufacturing a heater assembly for an aerosol generating system according to any one of Examples 16 to 18, wherein the step of bonding the heating element to the heating surface of a porous ceramic body includes depositing the heating element onto the porous ceramic body by thick-film technology such as screen printing, inkjet printing, aerosol jet printing, or laser direct structuring. Example 22. A method for manufacturing a heater assembly for an aerosol generating system according to any one of Examples 16 to 21, wherein the step of bonding the heating element to the heating surface of a porous ceramic body includes depositing the heating element onto the porous ceramic body by thin-film technology such as physical vapor deposition or chemical vapor deposition. Example 23. A method for manufacturing a heater assembly for an aerosol generating system according to any one of Examples 16 to X22, wherein the step of bonding a heating element to the heating surface of a porous ceramic body includes molding the heating element and the porous ceramic body. Example 24. An aerosol generating system comprising a heater assembly according to any one of Examples 1 to 15, wherein the heating element is fluid permeable so that vapor is released from the heater assembly in the mean vapor discharge direction during use, the aerosol generating system further comprises an air intake and an aerosol outlet, the air intake is in fluid communication with the aerosol outlet to define an airflow path through the aerosol generating system, the heater assembly is arranged in fluid communication with the airflow path so that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

[0131] Herein, the present invention will be further explained with reference to the attached drawings, although this is purely illustrative. [Brief explanation of the drawing]

[0132] [Figure 1] Figure 1 shows a schematic cross-sectional view of a heater assembly according to one embodiment of the present disclosure, in which the heating element is a porous layer. [Figure 2] Figure 2 shows a schematic diagram of a heater assembly according to one embodiment of the present disclosure. [Figure 3] Figure 3 shows a schematic cross-sectional view of the heater assembly shown in Figure 2. [Figure 4] Figure 4 is a schematic diagram of the interior of an aerosol generation system according to one embodiment of the present disclosure. [Figure 5]Figure 5 is a schematic cross-sectional view of a portion of an aerosol generating system according to another embodiment of the present disclosure, showing the arrangement of a heater assembly with respect to the airflow path within the aerosol generating system. [Figure 6] Figure 6 is a schematic cross-sectional view of a portion of an aerosol generating system according to another embodiment of the present disclosure, showing an alternative arrangement of the heater assembly relative to the airflow path within the aerosol generating system. [Figure 7] Figure 7 shows a schematic diagram of an example of a heater assembly for an aerosol generation system. [Figure 8] Figure 8 shows a schematic diagram of an example of a heater assembly for an aerosol generation system. [Figure 9] Figure 9 shows a heater assembly for use in an aerosol generation system according to one embodiment of the present disclosure, the heater assembly comprising a heating element for vaporizing a liquid aerosol forming substrate. [Figure 10] Figure 10 shows a schematic cross-sectional view of a heater assembly for an aerosol generation system according to one embodiment of the present disclosure. [Figure 11] Figure 11 shows a schematic cross-sectional view of another embodiment of a heater assembly for an aerosol generation system according to one embodiment of the present disclosure. [Figure 12] Figures 12(a) to 12(c) show schematic diagrams of different heating elements for an aerosol generation system according to one embodiment of the present disclosure. [Figure 13] Figures 13(a) and 13(b) show schematic diagrams of the current flow around the corner of a heating element track according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0133] Herein, embodiments of the present invention will be described in detail, albeit only as illustrative examples, with reference to the accompanying drawings.

[0134] Figure 1 shows a schematic cross-sectional view of a heater assembly 100 according to one embodiment of the present disclosure, in which the heating element 110 is a porous layer. Referring to Figure 1, the heater assembly 100 comprises a heating element 110, a porous ceramic body 130, and an electrical control circuit (not shown for clarity).

[0135] The porous ceramic body 130 is configured to supply the liquid aerosol-forming substrate to the heating element 110. Specifically, the porous ceramic body 130 is configured to transfer the liquid aerosol-forming substrate from the liquid storage section (not shown in Figure 1 for clarity) to the heating element 110. The porous ceramic body 130 is configured to store some of the liquid aerosol-forming substrate before it is aerosolized by the heating element 110.

[0136] In this exemplary embodiment, the porous ceramic body 130 is a cylindrical block. The porous ceramic body 130 has a first end face and an opposing second end face. The first end face is a liquid absorption surface 134, and the second end face is a heating surface 133. In this embodiment, both the liquid absorption surface 134 and the heating surface 133 are substantially flat surfaces. The porous ceramic body 130 also has a side surface 131 extending between the liquid absorption surface 134 and the heating surface 133. The porous ceramic body 130 has a thickness defined between the liquid absorption surface 134 and the heating surface 133.

[0137] The porous ceramic body 130 includes a plurality of open pores. The plurality of open pores are interconnected to provide a fluid path for the aerosol-generating liquid to pass through the porous ceramic body 130.

[0138] The open pores are generally axially oriented pores that extend from the liquid absorption surface 134 to the heated surface 133 of the porous ceramic body. The pore size of the pores within the porous ceramic body 130 varies between the liquid absorption surface 134 and the heated surface 133.

[0139] The porous ceramic body 130 includes a heating end and a liquid absorption end, with the heating surface 133 located at the heating end and the liquid absorption surface 134 located at the liquid absorption end. The porous ceramic body includes a first average pore size at the liquid absorption end and a second average pore size at the heating end. The first average pore size is larger than the second average pore size.

[0140] The first pore size at the liquid absorption end is approximately 150 micrometers. The second pore size at the heating end is approximately 20 micrometers. The pore size changes linearly between the first and second pore sizes, providing a pore size gradient between the liquid absorption end and the heating end of the porous ceramic body 130.

[0141] The pore structure and pore size gradient of the porous ceramic body 130 are achieved by etching the pores into a portion of the silicon carbide.

[0142] The heater assembly 100 may be configured such that a liquid flows through a fluid path in the porous ceramic body 130 to the heating element 110, as indicated by the arrow 170. The porous ceramic body 130 is configured such that the fluid 170 passes from the liquid absorption surface 134 to the heating surface 133. The porous ceramic body 130 contains a material that does not chemically interact with the liquid aerosol-forming substrate. The porous ceramic body 130 contains a ceramic. The porous ceramic body 130 contains, but is not limited to, one or more porous ceramics such as Al2O3, ZrO2, Si3N4, SiC, Ti3AlC2, BN, AlN, SiO2, MgO, mica, diatomaceous earth, silicates, borides, and glass. It will be understood that the porous ceramic body 130 may have different shapes or contain different materials.

[0143] The heating element 110 is configured to heat the liquid aerosol-forming substrate in order 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.

[0144] The heating element 110 is positioned along the heating surface 133 of the porous ceramic body 130. The heating element 110 is in direct contact with the porous ceramic body 130.

[0145] The heating element 110 is a porous heating element. The heating element 110 extends to cover the area of ​​the heated surface 133 of the porous ceramic body 130.

[0146] The heating element 110 has a first end face and an opposing second end face. The first end face is the liquid-absorbing surface 114, and the second end face is the outer surface 113. In this embodiment, both the liquid-absorbing surface 114 and the outer surface 113 are substantially flat surfaces. The liquid-absorbing surface 114 of the heating element 110 is bonded to the heating surface 133 of the porous ceramic body 130 by an adhesive layer 115. In this exemplary embodiment, the heating element 110 is a cylindrical block. The heating element 110 has a side surface 111 extending between the liquid-absorbing surface 114 and the outer surface 113. The heating element 110 has a thickness defined between the liquid-absorbing surface 114 and the outer surface 113.

[0147] Figure 2 is a schematic diagram of the interior of an aerosol generating system 300 according to one embodiment of the present disclosure. The aerosol generating system 300 comprises two main components, a cartridge 301 and a main body or aerosol generating device 400. The cartridge 301 is detachably connected to the aerosol generating device 400. In this embodiment, the aerosol generating device 400 comprises a power source in the form of a battery 402, which is a rechargeable lithium-ion battery, and a device housing 301 that houses a control circuit 403. The aerosol generating system 300 is portable and has a size comparable to a conventional cigar or cigarette. A mouthpiece is located at the mouth end of the cartridge 301.

[0148] The cartridge 301 comprises a heater assembly 100 and a cartridge housing that contains a liquid storage section or liquid storage portion 303 for holding a liquid aerosol-forming substrate. The liquid aerosol-forming substrate is carried downward from the liquid absorption surface 134 through the porous material to the heating element, and when power is supplied to the heating element, the vaporized aerosol-forming substrate is released from the heating surface 133.

[0149] The cartridge 301 includes one or more air intake ports 304 formed within the cartridge housing 305 at positions along the length of the cartridge 301. The aerosol outlet 306 is located in the mouthpiece at the mouth end of the cartridge 301. The one or more air intake ports 304 are in fluid communication with the aerosol outlet 306 to define the airflow path through the cartridge 301 of the aerosol generating system 300. The airflow path flows from the one or more air intake ports 304 to the heater assembly 100 in the airflow channel. The heater assembly 100 is positioned to be in fluid communication with the airflow path in the airflow channel. Air enters the one or more air intake ports 304, flows through the airflow channel, passes through the heater assembly 100, and flows in the mean airflow direction.

[0150] In the embodiment shown in Figure 4, the liquid storage section 303 is arranged around a centrally sealed aerosol channel 307, which has an annular cross-section. When the airflow path reaches the heater assembly 100, it turns upward around the side of the heater assembly 100 and flows through the aerosol channel 307 to the aerosol outlet 306.

[0151] The aerosol generating system 300 is configured so that a user can inhale or smoke the mouthpiece of the cartridge, thereby drawing an aerosol into their mouth through the aerosol outlet 306. During operation, when a user smokes the mouthpiece, air is drawn in through one or more air intake ports 304, passes through the airflow channels along the airflow path, around the heater assembly 100, through the aerosol channels 307 along the airflow path, and is drawn out to the aerosol outlet 306. The control circuit 403 controls the supply of power from the battery 402 to the cartridge 301 when the system is started. This then controls the amount and characteristics of the vapor produced by the heater assembly 100. The control circuit 403 includes an airflow sensor (not shown) that supplies power to the heater assembly 100 when the airflow sensor detects user inhalation. This type of control device is well established in aerosol generating systems such as inhalers and e-cigarettes. When the user inhales vapor through the mouthpiece of cartridge 301, the heater assembly 100 activates, generating vapor that is drawn into the airflow path. The vapor is cooled within the airflow path to form an aerosol, which is then inhaled into the user's mouth through the aerosol outlet 306.

[0152] Figure 5 is a schematic cross-sectional view of a portion of an aerosol generating system 500 according to another embodiment of the present disclosure, showing the arrangement of the heater assembly 200 with respect to the airflow path 520 within the aerosol generating system 500. For simplification, other components of the aerosol generating system are omitted from Figure 5. The heater assembly 200 in Figure 5 is identical to the heater assembly 200 in Figures 1, 2, and 3. The aerosol generating system 500 includes a liquid storage portion 522 that holds a liquid aerosol-forming substrate in contact with the liquid-absorbing surface 202b of the porous body 202. The liquid aerosol-forming substrate is transported from the liquid storage portion 522 through the porous body 202 to the heating surface 202a, as indicated by arrow E. The vaporized aerosol-forming substrate is released from the heating surface 202a through the porous heating element 204. As indicated by arrow F, the mean vapor release direction is substantially perpendicular to the heating surface 202a of the porous body 202.

[0153] In the embodiment shown in Figure 5, the heater assembly 200 is positioned below or beside one side of the airflow channel or path 520, which is defined by the airflow channel wall 524. As shown in Figure 5, the left end of the visible portion of the airflow path 520 receives airflow from an air intake (not shown), and the right end of the visible portion of the airflow path delivers airflow to an aerosol outlet (not shown). The heating surface 202a of the porous body 202 is positioned parallel to the airflow path 520 and faces the airflow path 520. The heater assembly 200 is in fluid communication with the airflow path, as indicated by arrow G, so that the airflow in the airflow path flows through the heater assembly 200 in the mean airflow direction. The heater assembly 200 and the airflow path 520 are positioned such that the angle θ between the mean vapor discharge direction F and the mean airflow direction G is approximately 90 degrees, that is, substantially perpendicular to the mean airflow direction G. The average vapor discharge direction F has no velocity or directional component opposite to the average airflow direction G, 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 520, and the vapor is less likely to collide with the inner surface of the airflow channel wall 524.

[0154] Figure 6 is a schematic cross-sectional view of a portion of an aerosol generating system 600 according to another embodiment of the present disclosure, showing an alternative arrangement of the heater assembly 200 with respect to the airflow path 620 within the aerosol generating system 600. For simplification, other components of the aerosol generating system are omitted from Figure 6. The heater assembly 200 in Figure 6 is identical to the heater assembly 200 in Figures 2 and 3. The aerosol generating system 600 includes a liquid storage portion 622 that holds a liquid aerosol-forming substrate in contact with the liquid-absorbing surface 202b of the porous body 202. The liquid aerosol-forming substrate is transported from the liquid storage portion 622 through the porous body 202 to the heated surface 202a, as indicated by arrow E. The vaporized aerosol-forming substrate is released from the heated surface 202a through the porous heating element 204. As indicated by arrow F, the mean vapor release direction is substantially perpendicular to the heated surface 202a of the porous body 202.

[0155] In the embodiment of Figure 6, the airflow channel or path 620 is divided into first and second airflow path sections 620a and 620b that pass through both sides of the heater assembly 200. The first airflow path section 620a and the second airflow path section 620b merge into a third airflow path section 620c downstream of the heater assembly 200. The first airflow path section 620a and the second airflow path section 620b receive airflow from one or more air intakes (not shown), and the third airflow path section 620c delivers airflow to an aerosol outlet (not shown). The airflow path 620 is defined by the airflow channel wall 624. The heating surface 202a of the porous body 202 is positioned substantially perpendicular to the airflow path 620 and faces downstream of the airflow path 620. The heater assembly 200 is in fluid communication with the airflow path, as indicated by arrow G, such that the airflow within the airflow path flows through the heater assembly 200 in the direction of the mean airflow.

[0156] The heater assembly 200 and the airflow path 220 are arranged such that the angle θ between the mean vapor release direction F and the mean airflow direction G is less than 90 degrees. Upstream of the heated surface 202a of the porous body 202, the mean airflow direction G passing through the heater assembly 200 is substantially the same as the vapor release direction F. Where the airflow path 620 corresponds to the heated surface 202a, the airflow path 620 narrows inward or tapers off, and at that point, the mean airflow direction G passing through the heater assembly 200 changes to an angle θ of approximately 45 degrees with respect to the vapor release direction F. Downstream of the heated surface 202a of the porous body 202 in the third airflow path section 620c, the mean airflow direction G of the integrated airflow is also substantially the same as the vapor release direction F. It will be understood that the narrowing or taper of the airflow path 620 may be omitted. In that case, the average airflow direction G passing through the heater assembly 100 is substantially the same as the steam discharge direction F.

[0157] Figures 7 and 8 show schematic diagrams of one embodiment of a heater assembly 700 for an aerosol generation system. The heater assembly includes a heating element 710 and a porous body 720.

[0158] The heating element 710 is configured to vaporize an aerosol-forming substrate, such as a liquid aerosol-forming substrate, to form an aerosol. The heating element 710 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 710 to electric current. In this exemplary embodiment, the heating element 710 is in direct contact with the porous ceramic body 720.

[0159] The porous body 720 is configured to transport the liquid aerosol-forming substrate to the heating element 710. In other words, the porous body 720 supplies the liquid aerosol-forming substrate to the heating element 710.

[0160] The porous body 720 has a first end face and an opposing second end face. The first end face is the liquid absorption surface 730, and the second end face is the heating surface 740. In this embodiment, both the liquid absorption surface 730 and the heating surface 740 are substantially flat surfaces. The porous body 720 also has a plurality of sides extending between the liquid absorption surface 730 and the heating surface 740.

[0161] In this embodiment, as will be discussed in more detail below, the porous body 720 has a first side surface 750 facing the second side surface 760, and a third side surface 770 facing the fourth side surface 780.

[0162] The porous body 720 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 720 from the liquid absorption surface 730 to the heating surface 740. The porous body 720 is formed from a material that does not chemically interact with the liquid aerosol-forming substrate. In this embodiment, the porous body 720 is a porous ceramic body, which may be formed from, for example, Ca2SiO3 or SiO2 (or Ca2SiO3 and SiO2).

[0163] The heating element 710 is located on and bonded to the heating surface 740 of the porous body 720. In the embodiments of Figures 7 and 8, the heating element 710 is a porous film that extends substantially across the entire heating surface 740.

[0164] The liquid-absorbing surface 730 of the porous body 720 has a different region from the heated surface 740 of the porous body 720. Specifically, in the embodiments shown in Figures 7 and 8, the area of ​​the heated surface 740 is smaller than the area of ​​the liquid-absorbing surface 730.

[0165] In the embodiments shown in Figures 7 and 8, the length of the heating surface 740 is shorter than the length of the liquid absorption surface 730, so the heating surface 740 has a smaller area than the liquid absorption surface 730. In addition, or alternatively, in another embodiment, the width of the heating surface 740 is smaller than the width of the liquid absorption surface 730, so the heating surface 740 may have a smaller area than the liquid absorption surface 730.

[0166] In the embodiments shown in Figures 7 and 8, the porous body 720 is formed as a trapezoidal prism. With the porous body 720 having a trapezoidal prism shape, the first side surface 750 and the second side surface 760 are both trapezoidal, particularly isosceles trapezoidal, the third side surface 770 and the fourth side surface 780 are both rectangular, and the liquid absorption surface 730 and the heating surface 740 are both rectangular. In another embodiment, the liquid absorption surface 730 and the heating surface 740 may have a square shape.

[0167] The porous body 720 tapers from the liquid-absorbing surface 730 towards the heating surface 740. In other words, the cross-sectional area of ​​the porous body 720 gradually decreases from the liquid-absorbing surface 730 towards the heating surface 740. In the embodiments shown in Figures 7 and 8, the length of the porous body 720 decreases and tapers from the liquid-absorbing surface 730 towards the heating surface 740.

[0168] Figure 9 shows a heater assembly 900 for use in an aerosol generation system. The heater assembly 900 comprises a heating element 910 for vaporizing a liquid aerosol-forming substrate. The heater assembly 900 also comprises a porous body 920 for transporting the liquid aerosol-forming substrate to the electric heating element 910. The porous body 920 has a liquid-absorbing surface 921 and an opposing heating surface 922. The heating element 910 is located on the heating surface 922 of the porous body 920. The porous body 920 can be made from any suitable ceramic material, such as the materials discussed in any of the above embodiments.

[0169] The heated surface 922 of the porous body 920 is curved. In particular, the heated surface 922 of the porous body 920 is curved convexly in a single transverse direction (first transverse direction).

[0170] The porous body 920 has a prismatic shape. When viewing a cross-section of the porous body 920 in the direction of its major axis perpendicular to the curvature direction, the heated surface 922 of the porous body 920 is shown as an arc. The porous body 920 has two planes of symmetry in the direction of its major axis.

[0171] The heating surface 922 of the porous body 920 has a width 923 in the first transverse direction that is substantially the same as the width of the porous body 920 in the first transverse direction, and also substantially the same as the width of the heater assembly 900 in the first transverse direction. The heating surface 920 of the porous body 920 has a width of approximately 5 millimeters in the first transverse direction.

[0172] The heated surface 922 of the porous body 920 has a length or thickness 924 of approximately 1 millimeter. The porous body 920 has a length or thickness 925 of approximately 3 millimeters.

[0173] The heated surface 922 of the porous material has a curvature of approximately 3.6 millimeters. The heated surface 922 of the porous material has a surface area of ​​approximately 28 square millimeters.

[0174] The porous body 920 has four longitudinal surfaces or side walls extending from the liquid-absorbing surface 921 to the heating surface 922. The four side walls are substantially perpendicular to the liquid-absorbing surface 921, which is substantially flat. The liquid-absorbing surface 921 has a square shape.

[0175] The heating element 910 is a resistance heating element and is curved. In particular, the curvature of the heating element 910 is substantially the same as the curvature of the heating surface 922 of the porous body 920. Thus, the heating element 910 is also curved convexly in a single transverse direction.

[0176] The heating element 910 is located directly on the heating surface 922 of the porous body 920. The heating element 910 extends over most of the heating surface 922 of the porous body 920. Substantially the entire heating element 910 is in contact with the heating surface 922 of the porous body 920.

[0177] Figure 10 shows a schematic cross-sectional view of a heater assembly 1000 for an aerosol generation system according to one embodiment of the present disclosure. The heater assembly 1000 comprises a heating element 1010, an insulating layer 1020, and a porous body 1030. The porous body 1030 is configured to supply a liquid aerosol-forming substrate to the heating element 1010. Specifically, the porous body 1030 is configured to transfer the liquid aerosol-forming substrate from a liquid storage unit (not shown) to the heating element 1010. The porous body 1030 is configured to store some of the liquid aerosol-forming substrate before it is aerosolized by the heating element 1010.

[0178] The porous body 1030 is a rectangular block having a first end face and an opposing second end face. The first end face is a liquid absorption surface 1034, and the second end face is a heating surface 1033. In this embodiment, both the liquid absorption surface 1034 and the heating surface 1033 are substantially flat surfaces. The porous body 1030 also has a plurality of sides extending between the liquid absorption surface 1034 and the heating surface 1033. The porous body 1030 has a first side face 1031 opposite to a second side face 1032, and a third side face (not shown) opposite to a fourth side face (not shown). The porous body 1030 has a thickness defined between the liquid absorption surface 1034 and the heating surface 1033.

[0179] The porous body 1030 contains a plurality of open pores. The plurality of open pores are interconnected to provide a fluid path for the aerosol-generating liquid to pass through the porous ceramic body 1030. The heater assembly 1000 may be configured such that the liquid flows through the fluid path of the porous body 1030 to the heating element 1010, as indicated by the arrow 1070. The porous body 1030 is configured so that the fluid 1070 passes from the liquid absorption side 1034 to the heating surface 1033. The porous body 1030 includes a material that does not chemically interact with the liquid aerosol-forming substrate. The porous body 1030 includes a ceramic. The porous body 1030 includes, but is not limited to, one or more porous ceramics such as Al2O3, ZrO2, Si3N4, SiC, Ti3AlC2, BN, AlN, SiO2, MgO, mica, diatomaceous earth, silicates, silicides, and borides. Alternatively, the porous body 830 may contain porous glass. It will be understood that the porous body 1030 may have a different shape or contain a different material.

[0180] The heating element 1010 is configured to heat the liquid aerosol-forming substrate in order to form an aerosol. The heating element 1010 is configured to convert electrical energy into thermal energy through the material resistance of the heating element 1010 to electric current.

[0181] The heating element 1010 includes a track that defines a path across the heating surface 1023 of the insulation layer 1020. The heating element 1010 defines a meandering or electrically parallel track shape across the heating surface 1023 of the insulation layer 1020. Figure 12 shows three cross-sections passing through a portion of the track of the heating element 1010. The multiple track portions are arranged such that the distance between at least two of the multiple track portions 1218, 1219 is in the range of 200 to 300 micrometers. The track portions are evenly spaced. It will be understood that the distances between at least two of the multiple track portions 1218, 1219 do not have to be equal.

[0182] The heating element 1010 is elongated and includes, but is not limited to, metals such as stainless steel, Ni-Cr alloy, NiCrAlY alloy, FeCrAl alloy (e.g., Kanthal), FeCrAlY alloy, Fe3Al alloy, Ni3Al alloy, NiAl alloy, and CuNi alloy. Naturally, the heating element 810 may have a different shape or contain different materials.

[0183] The heating element 1010 is arranged along the outer surface of the insulation layer 1020. The heating element 1010 is in direct contact with the insulation layer 1020.

[0184] The insulation layer 1020 is arranged to enhance the insulation between the heat-generating element 1010 and the porous body 1030. The insulation layer 1020 extends over at least a portion of the heat-generating element 1010 and is arranged to insulate the heat-generating element 1010 from the porous body 1030. The insulation layer 1020 is configured to reduce heat dissipation through the porous body 1030 in order to improve energy efficiency by reducing energy loss.

[0185] The thermal insulation layer 1020 is planar and has a size and shape configured to extend across the electric heating element 1010. The thermal insulation layer 1020 is configured to extend completely across the surface of the heating element 1010. The thermal insulation layer 1020 is configured to substantially cover the porous body 1030 beneath the thermal insulation layer 1020.

[0186] The thermal insulation layer 1020 has a first end face 1024 and an opposing second end face 1023. In this embodiment, both the first end face 1024 and the second end face 1023 are substantially flat surfaces. The first end face 1024 of the thermal insulation layer 820 is in direct contact with the porous ceramic body 1030. The second end face 1023 of the thermal insulation layer 1020 is in direct contact with the heating element 1010.

[0187] The thermal insulation layer 1020 has a thickness defined between the first end face 1024 and the second end face 1023. The thickness of the thermal insulation layer 1020 is thinner than the thickness of the porous body 1030. The thermal insulation layer 1020 may have a thickness of 0.1 mm to about 2 mm, preferably 0.5 mm to 1.5 mm.

[0188] The thermal insulation layer 1020 contains a material having a low thermal conductivity. The thermal insulation layer 1020 contains, or consists of, a material having a lower thermal conductivity than the porous ceramic body 1030. The thermal insulation layer 1020 may have a higher porosity than the porous ceramic body 1030. The thermal insulation layer 1020 may contain one or more materials such as alumina, zirconia, zirconia with magnesium oxide, glass ceramic, quartz, and porous polymer. It will be understood that the thermal insulation layer 1020 may have different shapes or contain different materials.

[0189] Figure 11 shows a schematic cross-sectional view of heater assembly 1001 of another embodiment for an aerosol generating system. Heater assembly 1001 in Figure 11 is identical to heater assembly 1000 in Figure 11, except that the heating element 1015 comprises a porous heating element. The porous ceramic body 1030 and the insulation layer 1020 are as described in relation to heater assembly 1000 in Figure 10, and the same reference numerals are used to label similar components.

[0190] The heating element 1015 extends to cover the area of ​​the second end face 1023 of the heat insulating layer 1020. The heating element 1015 has a liquid absorption surface 1014 and a heating surface 1013. In this embodiment, both the liquid absorption surface 1014 and the heating surface 1013 of the heating element 1015 are substantially flat surfaces. The liquid absorption surface 1014 of the heating element 1015 is in direct contact with the heat insulating layer 1020.

[0191] Referring to Figures 12(a) to 12(c), schematic diagrams of different heating elements 110 for an aerosol generation system are shown. Each heating element 110 comprises multiple tracks or track sections 117 arranged electrically in parallel. By being arranged electrically in parallel, the current flow is divided into separate parallel channels. The channels are then reintegrated.

[0192] In the heating elements 110 shown in Figures 12(a) to 12(c), each heating element 110 includes a first connection pad 113 and a second connection pad 114. The first connection pad 113 and the second connection pad 114 are configured to allow connection to an external circuit. One or more openings 115 within the heating element 110 isolate each track 117. Each heating element 110 includes a branching section where the current is split from the first connection pad 113 to the tracks 117 which define electrically parallel paths. Each heating element 110 includes a converging section that integrates the current from the tracks 117 which define electrically parallel paths and leads it into the second connection pad 114.

[0193] Various different arrangements of electrically parallel tracks or track sections are possible. In Figure 12(a), four tracks 117 are separated by three openings 115 to define four electrically parallel paths. In Figure 12(b), six track sections 117 are separated by one opening 115 to define two electrically parallel paths. In Figure 12(b), each electrically parallel path defines a meandering path between a first connection pad 113 and a second connection pad 114. In Figure 12(c), eight track sections 117 are separated by four openings 115 to define four pairs of electrically parallel paths. In Figure 12(c), each pair of electrically parallel paths is separated by an intermediate connection 116, three of which are shown in Figure 12(c).

[0194] By electrically arranging the 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 110, i.e., the electrical connection between the first connecting pad 113 and the second connecting pad 114 is not damaged. This has the advantage of increasing the number of fume extractions before the heater completely fails, potentially extending the heater's lifespan to the end of the device's life. In contrast, in a simple meandering heater that defines a single electrical path between the first connecting pad 113 and the second connecting pad 114, 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 failure in a simple meandering heater causes an increase in local resistance. An increase in local resistance causes an increase in power loss. The increase in power loss then increases the resistance until failure occurs.

[0195] The inventors also identified that electrically parallel-arranged parallel tracks or track sections, as illustrated with reference to Figures 12(a)-(c), have a surprising additional advantage. In such arrangements, if one track section fails, the heating element can still operate and, for an initial transient period, operate in a favorable manner because 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 throughput is increased over a smaller area. Such failures may cause an increase in current on the undamaged tracks or track sections, ultimately degrading the user experience, but the device or cartridge can incorporate a mechanism to warn the user of the potential future performance degradation of the heater assembly.

[0196] 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 (the more parallel tracks there are, the lower the total resistance), 2) Cross-sectional area of ​​parallel heating tracks (width or thickness (or width and thickness)) (the larger the cross-sectional area, the lower the resistance), 3) The length of the parallel heating tracks (the longer the tracks, the greater the 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).

[0197] 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 , R i This is shown in Equation 4,

number

[0198] In the formula, n is the total number of heating tracks that are electrically connected in parallel.

[0199] The operation of a parallel track heating element when one heating track fails can be considered, for example, by referring to a heating element having four parallel heating tracks, as shown in Figure 12(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 4.

[0200] When one heating track begins to fail, the resistance of the failed heating track increases. The total resistance of the heating element also begins to increase, following a linear relationship with the resistance of the defective heating track. However, as the heating track resistance continues to increase, the heating element resistance asymptotically approaches a constant resistance value. At this constant resistance value, the effect of the defective heating track on the heating element resistance is limited. In this embodiment, where each undamaged heating track has a resistance of 3 ohms, if the failed track can be considered an open circuit (i.e., no further current flows through it), the total resistance of the heating element asymptotically approaches 1 ohm. In this embodiment, if one track fails, only three tracks remain for the purpose of calculating the total resistance of the heating element.

[0201] To account for the operation of these heating elements, a supply voltage of 3.5 volts and a target power of 5.5 watts are considered. In this embodiment, the undamaged parallel heating track remains at an initial resistance of 3 ohms. In the faulty track, the total maximum current decreases as the resistance increases. In the faulty track, the current decreases to zero upon failure. Even as the resistance of the faulty track increases, the current through the undamaged parallel track remains substantially constant (ignoring resistance changes due to temperature rise).

[0202] A similar trend is observed for maximum power generation. When a heating track fails, the total power generated decreases. However, in this embodiment, despite the failure of one of the heating tracks, the maximum power remains above the target of 5.5 watts.

[0203] The device or cartridge may also be configured to extend the lifespan of the parallel track heating elements. The 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 of 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 (up to 67.4 percent in the current embodiment). Therefore, a heating element with four parallel heating tracks can still operate under nominal conditions of 5.5 watts, even if two of these heating tracks are damaged, because the load cycle remains below 100 percent.

[0204] 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 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.

[0205] Referring to Figures 13(a) and 13(b), schematic diagrams of the current flow 1309 around the corner of the heating element track are shown.

[0206] Figure 13(a) is a schematic diagram of current flow 1309 around a 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 is concentrated (i.e., there is an increase in current density) indicated by arrow 1309 following the path of least resistance. This concentration occurs at the inner end of the corner. The current concentration can raise the local temperature, potentially causing 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 possibility that the local resistivity of the heater track material increases due to the local rise in temperature (this causes current to flow through the path of lower resistance).

[0207] Figure 13(b) is a schematic diagram of the current flow 1309 around a heating element, where the track portion 1317 defines a path with bends, and the inner end of the bend is curved. In such a track 1317, the current flow 1309 does not form localized hot spots.

[0208] In contrast to the track shape shown in Figure 13(a), the current flow 1309 in a smoother, curved section of the track 1317, as shown in Figure 13(b), remains more evenly distributed across the heating track 1317, as indicated by the dashed arrow 1309. The current flow 1309 is induced to flow more evenly, avoiding current concentration at any given point. This limits the creation of hot spots. The heating track 1317 may have a resistivity gradient perpendicular to the current flow at one or more corners, such that the resistivity is higher in the inner portion of the corner and lower in the outer portion of the corner. Such gradients are beneficial in offsetting localized high current densities and reducing hot spot generation.

Claims

1. A heater assembly for an aerosol generation system, A heat-generating element for vaporizing the liquid aerosol-forming substrate, A porous ceramic body for transporting the liquid aerosol forming substrate to the heating element, comprising the porous ceramic body having a liquid absorption surface and a heating surface, A heater assembly in which the heating element is located on and bonded to the heating surface of the porous ceramic body.

2. The heater assembly according to claim 1, wherein the heating element is in contact with the heating surface of the porous ceramic body, and the heating element and the heating surface of the porous ceramic body are bonded together by this contact.

3. The heater assembly according to claim 1, wherein the heating element and the heating surface of the porous ceramic body are bonded together by an intervening layer located between the heating element and the heating surface of the porous ceramic body.

4. The heater assembly according to any one of claims 1 to 3, wherein the heating element is a porous ceramic heating element.

5. The heater assembly according to claim 4, wherein the heating element is a doped portion of the porous ceramic heating element.

6. The heater assembly according to any one of claims 1 to 3, wherein the heating element is a metal heating element such as a metal heating truck.

7. The heater assembly according to any one of claims 1 to 4, wherein the heating element is deposited on the porous ceramic body by a thick film technology such as screen printing, inkjet printing, aerosol jet printing, or laser direct structuring.

8. The heater assembly according to any one of claims 1 to 4, wherein the heating element is deposited by thin-film technology such as physical vapor deposition or chemical vapor deposition.

9. The heater assembly according to any one of claims 1 to 6, wherein the heating element and the porous ceramic body are joined by molding.

10. The heater assembly according to any one of claims 1 to 6, wherein the heating element and the porous ceramic body are formed separately and assembled to form the heater assembly.

11. The heater assembly according to any one of claims 1 to 10, wherein the liquid-absorbing surface of the porous ceramic body has an area different from the area of ​​the heating surface of the porous body.

12. The heater assembly according to any one of claims 1 to 11, 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.

13. The heater assembly according to any one of claims 1 to 12, further comprising an insulating layer having a lower thermal conductivity than the porous body, wherein the insulating layer is disposed between the porous body and the heating element and in contact with each of them, and the insulating layer is configured to reduce heat transfer from the heating element to the porous body.

14. A method for manufacturing a heater assembly for an aerosol generation system, To form a heat-generating element for vaporizing the liquid aerosol-forming substrate, The method involves forming a porous ceramic body for transporting the liquid aerosol-forming substrate to the heating element, wherein the porous ceramic body has a liquid-absorbing surface and a heating surface. A method comprising bonding the heating element to the heated surface of the porous ceramic body.

15. The heating element is fluid permeable so that steam is released from the heater assembly in the average steam discharge direction during use. The aerosol generating system further comprises an air intake and an aerosol outlet, the air intake and the aerosol outlet are in fluid communication, defining an airflow path through the aerosol generating system. An aerosol generating system comprising a heater assembly according to any one of claims 1 to 13, wherein the heater assembly is arranged in fluid communication with the airflow path such that air flows through the heater assembly in the mean airflow direction, and the heater assembly and the airflow path are arranged such that the angle between the mean vapor discharge direction and the mean airflow direction is less than 135 degrees.

Images