A charging assembly for an aerosol generating device, an aerosol generating device, and a method of using a charging assembly

Abstract

A charging assembly (12) for an aerosol generating device is described. The charging assembly (12) includes an electrically conductive, tubular, receiving coil for wireless inductive charging of an energy storage device. The coil (20) has a first end (20a) that defines a fluid inlet and a second end (20b) that defines a fluid outlet. The first and 10 second ends (20a, 20b) are electrically connectable to the energy storage device by means of a charging circuit. An air-cooled heat exchanger includes a tubular heat transfer member (32) arranged in a heat transfer space (40) adapted to receive air (or another secondary heat transfer fluid). The heat transfer member (32) has a first end that defines a fluid inlet and a second end that defines a fluid outlet. The fluid inlet of 15 the heat transfer member (32) is fluidly connected to the fluid outlet of the coil (20) and the fluid outlet of the heat transfer member (32) is fluidly connected to the fluid inlet of the coil (20) to define a closed-loop heat transfer circuit. A primary heat transfer fluid is circulated around the closed-loop heat transfer circuit by natural convection.

Description

[0001] A CHARGING ASSEMBLY FOR AN AEROSOL GENERATING DEVICE, AN AEROSOL GENERATING DEVICE, AND A METHOD OF USING A CHARGING ASSEMBLY

[0002] Technical Field

[0003] The present disclosure relates generally to a charging assembly of an aerosol generating device, and in particular a device that is adapted to heat aerosol generating material to generate an aerosol for inhalation by a user. The charging assembly may be used for wireless charging of an energy storage device (e.g., a rechargeable battery) of the aerosol generating device. The present disclosure also relates generally to a method of using the charging assembly to transfer heat away from a coil of the charging assembly and / or any heat-generating component that is heat coupled to the coil.

[0004] The present disclosure also relates generally to an aerosol generating device. The present disclosure is particularly applicable to a portable (hand-held) aerosol generating device.

[0005] Technical Background

[0006] Devices which heat, rather than burn, an aerosol generating material to produce an aerosol for inhalation have become popular with consumers in recent years. A commonly available reduced-risk or modified-risk device is the heated material aerosol generating device, or so-called heat-not-bum device. Devices of this type generate an aerosol or vapour by heating an aerosol generating material to a temperature typically in the range 150°C to 300°C. This temperature range is quite low compared to an ordinary cigarette. Heating the aerosol generating material to a temperature within this range, without burning or combusting the aerosol generating material, generates a vapour which typically cools and condenses to form an aerosol for inhalation by a user of the device.

[0007] The aerosol generating material may be a solid or liquid. For example, the aerosol generating article may include a solid or semi-solid substrate of plant derived material, such as tobacco, or it may include a wick and a heater to produce vapour from aerosol generating liquid stored in a capsule or tank. When a user operates the aerosol generating device, liquid that has soaked into the wick is heated by the heater, producing a vapour which cools and condenses to form an aerosol which may then be inhaled. An aerosol generating article (sometimes called a pod or cartridge) may be received in the aerosol generating device and may include a liquid store, a liquid transfer element (e.g., a wick) and a heater. Electrical contacts may provide an electrical connection between the heater and an energy storage device of the aerosol generating device. The energy storage device may be a rechargeable battery that may be charged from an external power source by a charging assembly of the aerosol generating device. A stick that looks like an ordinary cigarette may also be used as an aerosol generating article.

[0008] The charging assembly may include an inductive receiving coil suitable for wireless charging of the battery. In particular, a wireless external power source such as a wireless charger will include an inductive transmitting coil that creates an electromagnetic field when an electric current flows through it. The inductive transmitting coil and the inductive receiving coil may also be referred to a primary coil and a secondary coil, respectively. When the receiving coil of the charging assembly of the aerosol generating device is in close proximity with the wireless charger, the electromagnetic field generates an electric current in the receiving coil of the charging assembly that may be provided to a charging circuit and used to charge the battery. Wireless charging is a convenient way to charge the battery without having to physically and / or mechanically connect a charging cable to the aerosol generating device. New ingress protection standards may also mean that wired charging assemblies, e.g., those that might include a plug socket such as a universal serial bus (USB) socket (receptacle) for receiving a USB charging cable (plug), and which therefore also require an opening in the housing, may no longer be suitable for use in aerosol generating devices. Using wireless charging may also avoid the need for a user to carry or use a separate charging cable. But there may be a limit on the size of the receiving coil that can be positioned within the housing of the aerosol generating device and high electric currents may need to be generated in order to meet expected charging times. This may result in excessive heat being generated by the receiving coil and related components during charging. The heat that is generated should not be fully dissipated into the housing to improve device safety. The housing will normally be made of a plastics material because an electrically conductive material cannot be positioned between the receiving coil of the charging assembly and the transmitting coil of the external wireless charger if a wireless connection between the receiving and transmitting coils is to be established. This may make dissipating the heat even more difficult because the thermal conductivity and thermal capacity of plastics materials are generally lower than the thermal conductivity and thermal capacity of electrically conductive materials such as metals, for example. Generating excessive heat within the housing may accelerate degradation of other internal components of the aerosol generating device. There is therefore a need for an improved charging assembly that may improve the transfer of heat that is generated during wireless charging away from the receiving coil.

[0009] Summary of the Disclosure

[0010] According to a first aspect of a present disclosure, there is provided a charging assembly for an aerosol generating device, the charging assembly comprising: an electrically conductive, tubular, receiving coil for wireless inductive charging of an energy storage device (e.g., a rechargeable battery such as a lithium- ion secondary battery of the aerosol generating device), the coil comprising a first end that defines a fluid inlet and a second end that defines a fluid outlet, wherein the first and second ends are electrically connectable to the energy storage device by means of a charging circuit; a heat exchanger comprising a tubular heat transfer member arranged in a heat transfer space adapted to receive a secondary heat transfer fluid, the heat transfer member comprising a first end that defines a fluid inlet and a second end that defines a fluid outlet, wherein the fluid inlet of the heat transfer member is fluidly connected to the fluid outlet of the coil and the fluid outlet of the heat transfer member is fluidly connected to the fluid inlet of the coil to define a closed-loop heat transfer circuit; and a primary heat transfer fluid in the closed-loop heat transfer circuit. Circulating the primary heat transfer fluid around the closed-loop heat transfer circuit will transfer heat away from the coil during wireless charging. More particularly, the heat generated by the coil during wireless charging is transferred into the circulating primary heat transfer fluid - thereby cooling the coil. The heat is then transferred from the primary heat transfer fluid to the secondary heat transfer fluid by the heat exchanger - thereby cooling the primary heat transfer fluid. The heat is finally removed from the interior of the housing of the aerosol generating device - i.e., the housing in which the charging assembly and the energy storage device are located - by the secondary heat transfer fluid. The charging assembly may allow for faster wireless charging of the energy storage device because the receiving coil is less likely to overheat. It also reduces the amount of heat that is dissipated into the housing and so protects other internal components from overheating. In addition, if the temperature of the receiving coil changes significantly, the impedance and resistance values of the coil may also change and this may lead to a reduction in the efficiency of the wireless charging. The charging assembly is therefore beneficial because it minimises the temperature change of the receiving coil and helps to maintain high efficiency during wireless charging.

[0011] The charging assembly may also be used to transfer heat away from any heatgenerating component that is heat coupled to the coil. The coil may be directly heat coupled to the heat-generating component or indirectly by means of a suitable heat conducting component, glue or potting material. Such materials include resins, silicones and the like that may include additives such as metal particles (e.g., copper or aluminium) or particles of other suitable materials such as silica, alumina etc. The coil may be heat coupled to an energy storage device of the aerosol generating device, for example. Heat generated by the heat-generating component (e.g., by the energy storage device) during normal operation of the aerosol generating device may be transferred away from the heat-generating component by circulating the primary heat transfer fluid around the closed-loop heat transfer circuit. More particularly, the heat generated by the heat-generating component is transferred into the coil and the circulating primary heat transfer fluid - thereby cooling the component. The heat is then transferred from the primary heat transfer fluid to the secondary heat transfer fluid by the heat exchanger - thereby cooling the primary heat transfer fluid. The heat is finally removed from the interior of the housing of the aerosol generating device by the secondary heat transfer fluid. The charging assembly may allow for better performance of the heat-generating component because the component is less likely to overheat. It also reduces the amount of heat that is dissipated into the housing and protects other internal components from overheating. The charging assembly may be used to transfer heat away from the heat-generating component when the coil is not being used for wireless charging - i.e., when the coil itself is not generating heat. The charging assembly may also be used to transfer heat away from the heat-generating component when the coil is being used for wireless charging - i.e., when both the coil and the component are generating heat at the same time. This may be case if the heatgenerating component is an energy storage device which is being charged by the charging assembly, for example.

[0012] The primary heat transfer fluid may be circulated around the closed-loop heat transfer circuit by natural convection (or “free convection”) - i.e., where the movement of the primary heat transfer fluid is generated only by density differences due to temperature gradients, and not by any fluid mover such as a pump, for example. More particularly, primary heat transfer fluid that is locally heated will become less dense and will expand, thereby pushing the downstream primary heat transfer fluid through the coil towards the fluid outlet. This eventually results in circulation of the primary heat transfer fluid around the closed-loop heat transfer circuit. The circulation will occur even if the coil is arranged substantially horizontally, which may be the case during wireless charging for example. Natural convection provides a simple and reliable way of circulating the primary heat transfer fluid around the closed-loop heat transfer circuit without the need for additional components such as a pump. The natural convection mechanism may also be considered in terms of the heat generated by the coil and / or the heat-generating component working as an energy source for circulating the primary heat transfer fluid. Because no additional kinetic and / or electrical energy is needed, natural convection is available without limitation - e.g., it does not depend on any particular operating condition of the aerosol generating device. The primary heat transfer fluid may be a dielectric fluid. Using a dielectric fluid means that the primary heat transfer fluid does not influence the wireless charging process when an electric current is generated in the coil, for example. The primary heat transfer fluid may be a food-grade fluid, for example. The primary heat transfer fluid may be a liquid such as propylene glycol, de-ionised water, or a suitable oil such as a natural oil, synthetic oil, or mineral oil, for example. The primary heat transfer fluid may be a gas such as air or another suitable gas, for example.

[0013] The secondary heat transfer fluid may be ambient air and the heat exchanger may be an air-cooled heat exchanger, for example. Ambient air may pass through the heat exchange space past the tubular heat transfer member so that heat is exchanged between the primary heat transfer fluid and the ambient air. This heat exchange cools the primary heat transfer fluid in the heat transfer member. The cooled primary heat transfer fluid will flow towards the fluid outlet of the heat transfer member and into the receiving coil through the fluid inlet of the coil.

[0014] The coil may be made of copper alloy comprising from about 0.015 wt% to about 0.040 wt% phosphorus and the balance being copper (i.e., “phosphorous-deoxidized, high residual” copper alloy (UNS C12200)). Such a copper alloy has good electrical and heat transfer properties. However, the coil may be made of any other suitable metal or metal alloy.

[0015] The heat transfer member may be made of an electrically conductive material. In such an arrangement, it is normally important to electrically isolate the heat transfer member from the coil because otherwise, the electric current generated by the coil during wireless charging will also flow through the heat transfer member. This may reduce the efficiency of the wireless charging. The fluid outlet of the heat transfer member may be fluidly connected to the fluid inlet of the coil by an electrically non- conductive tubular first fluid connector. The fluid inlet of the heat transfer member may be fluidly connected to the fluid outlet of the coil by an electrically non- conductive tubular second fluid connector. This means that the fluid inlet (or first end) of the coil is not directly physically connected to the fluid outlet (or second end) of the heat transfer member, and the fluid inlet (or first end) of the heat transfer member is not physically connected to the fluid outlet (or second end) of the coil. The first and second fluid connectors may be made of a plastics or synthetic polymer material, for example, and function as electrical insulators. The first and second fluid connectors may be flexible which may allow for relative movement as a result of the thermal expansion of the coil and / or the heat transfer member. The first and second fluid connectors may also act as pressure release valves in case of excessive pressure in the closed-loop heat transfer circuit. The first and second fluid connectors may make it easier to assemble the charging assembly compared to using a completely rigid connection between the coil and the heat transfer member, for example.

[0016] The first and second fluid connectors may be connected to the fluid inlet and outlets (or first and second ends) of the coil and the heat transfer member using a suitable adhesive such as food-grade silicone adhesive, for example.

[0017] The heat transfer member may be made of copper alloy comprising about 0.001 wt% oxygen and the balance being copper (i.e., “oxygen free” copper alloy (UNS C 10200)) or about 0.04 wt% oxygen and the balance being copper (i.e., “electrolytic tough pitch” copper alloy (UNS Cl 1000)). Such a copper alloy has good heat transfer properties. However, the heat transfer member may be made of any suitable metal or metal alloy.

[0018] Heat exchange between the primary and secondary heat transfer fluids relies on the heat transfer member. Enhancing the transfer of heat through the wall of the tubular heat transfer member is therefore important to improve the cooling of the primary heat transfer fluid. If the heat transfer member is made of a suitable metal or metal alloy with a high thermal conductivity, there will be good heat exchange between the primary and secondary heat transfer fluid but there may be a reduction in the efficiency of wireless charging if an electric current is allowed to flow through the heat transfer member. Using the first and second fluid connectors allows the heat transfer member to be made of a metal or metal alloy with a high thermal conductivity, but also provides electrical isolation from the receiving coil so that high efficiency of wireless charging is maintained.

[0019] The heat transfer member may be made of an electrically non-conductive material. The heat transfer member may be made of a plastics or synthetic polymer material, for example. In this case, the electric current generated by the coil during wireless charging will not flow through the heat transfer member so the coil may be connected directly to the heat transfer member. In particular, the fluid inlet (or first end) of the coil may be directly physically connected to the fluid outlet (or second end) of the heat transfer member, and the fluid inlet (or first end) of the heat transfer member may be directly physically connected to the fluid outlet (or second end) of the coil. This allows the number of component parts of the charging assembly to be reduced, e.g., because the first and second fluid connectors may be omitted.

[0020] The coil and the heat transfer member may have a wall thickness in the range of about 0.05 mm to about 0.4 mm. A wall thickness of about 0.2 mm, for example, might be preferred for both the coil and the heat transfer member. If the wall thickness of the coil is low, it will provide better transfer of heat to the primary heat transfer fluid and may also help to reduce the skin effect when electric current is generated in the coil during wireless charging. If the wall thickness of the heat transfer member is low, it will provide better transfer of heat from the primary heat transfer fluid to the secondary heat transfer fluid in the heat transfer space. It will be understood that wall thickness is also important for maintaining mechanical strength. The range suggested above may provide good thermal transfer while still maintaining sufficient mechanical strength and rigidity for the coil and the heat transfer member.

[0021] The inner diameter of the coil may be less than the inner diameter of the heat transfer member. This means that the heat transfer member will have a larger surface area than the coil, but the coil may have better thermal conductivity. A larger surface area may provide improved heat exchange between the primary and secondary heat transfer fluids within the heat exchanger. It may also mean that the inner diameter of the closed-loop heat transfer circuit is reduced at the point where the cooled primary heat transfer fluid enters the coil through its fluid inlet. The reduction in the inner diameter may assist the circulation of the primary heat transfer fluid, i.e., the Venturi effect may increase the rate of fluid flow of the primary heat transfer fluid through the coil part of the closed-loop heat transfer circuit. The change in the rate of fluid flow is described by Bernoulli’s principle.

[0022] The coil may have an inner diameter of about 0.8 mm and an outer diameter of about 1.0 mm, for example.

[0023] The heat transfer member may follow a serpentine path and may include a plurality of bends or turns. The bends or turns may be spaced apart. This may increase the surface area of the part of the heat transfer member that is located within the heat transfer space and may improve the efficiency of transferring heat from the primary heat transfer fluid to the secondary heat transfer fluid. Between the fluid inlet and the fluid outlet, the heat transfer member may define one or more paths for the flow of the primary heat transfer fluid - e.g., there may be a single flow path (defined by a single tubular member) between the fluid inlet and the fluid outlet, or there may be two or more parallel flow paths between the fluid inlet and the fluid outlet, which parallel flow paths may be defined by respective tubular members. The fluid inlet and the fluid outlet may be arranged as manifolds, for example. Each tubular member may follow a serpentine path and may include a plurality of bends or turns.

[0024] The charging assembly may further comprise:

[0025] - a first electrical connector having a collar that is fixedly connected around the first end of the coil and a solder tab that optionally includes an opening, and

[0026] - a second electrical connector having a collar that is fixedly connected around the second end of the coil and a solder tab that optionally includes an opening.

[0027] The first and second electrical connectors provide a reliable way of making an electrical connection to the first and second ends of the coil. In particular, an end of a wire may be received through the optional opening of each electrical connector and then soldered to the respective solder tab, or simply soldered to the solder tab. The other end of each wire may be electrically connected to a printed circuit board assembly (PCBA). In particular, the PCBA may comprise a printed circuit board with first and second charging terminals and a charging circuit comprising one or more electronic components mounted to the printed circuit board. The PCBA may comprise a charging integrated circuit (IC), for example. The energy storage device may also be electrically connected to the PCBA (e.g., to a pair of energy storage device terminals on the printed circuit board) so that the electric current that is generated by the coil during wireless charging may be supplied to the charging circuit (e.g., to the charging IC) and then used to charge the energy storage device.

[0028] The coil between the first and second ends preferably comprises a plurality of turns arranged substantially in a common plane. The heat transfer member is preferably not arranged substantially in the common plane. For example, the heat transfer member may be arranged substantially in a plane that is substantially perpendicular to the common plane of the coil. This will ensure that an electric current is not generated in the heat transfer member during wireless charging.

[0029] According to a second aspect of the present disclosure, there is provided an aerosol generating device comprising: a charging assembly as described above; a charging circuit electrically connected to the first and second ends of the coil of the charging assembly; and an energy storage device (e.g., a rechargeable battery) electrically connected to the charging circuit.

[0030] The coil may be arranged adjacent the energy storage device and may be heat coupled to the energy storage device. This means that the coil of the charging assembly may also be used to transfer heat that is generated by the energy storage device during charging and also during normal operation of the aerosol generating device. The energy storage device may therefore be cooled by the charging assembly as described in more detail above. The aerosol generating device may further comprise a housing in which the charging assembly and the energy storage device are located. The housing may include at least one air opening that is in fluid communication with the heat transfer space. In this case, the secondary heat transfer fluid is air and the heat exchanger is an air-cooled heat exchanger. Air may therefore flow into and out of the heat transfer space through the at least one air opening. Heat is transferred from the primary heat transfer fluid flowing through the tubular heat transfer member to the air in the heat transfer space, which heated air may then flow out of the heat transfer space - i.e., out of the housing - through the at least one air opening. The heated air may be replaced by cooler air from outside the housing. In this way, heat that is generated within the housing either by the coil during wireless charging or by any other heat-generating component that is heat coupled with the coil, e.g., the energy storage device, may be removed from the housing by the air-cooled heat exchanger. The housing may include two or more air openings. For example, heated air may flow out of the heat transfer space through one air opening and cooler air may flow in to the heat transfer space through another air opening. Air may therefore be circulated through or flow through the heat transfer space past the heat transfer member to provide efficient removal of the heat that is generated inside the housing of the aerosol generating device. In one arrangement, the at least one air opening may be located at an end of the housing and may be spaced apart from the heat transfer space.

[0031] The heat transfer space may be sealed from the remainder of the housing interior. For example, the heat transfer space may be enclosed by a wall that is sealed to the housing so that the heat transfer space is separated from the remainder of the housing interior. The wall may define or be aligned with the at least one air opening - i.e., it may be open to the outside. The wall may be sealed to the housing using a glue seal or an O-ring, for example. This means that the heated air or other secondary heat transfer fluid in the heat transfer space cannot flow into the housing interior. It also means that the ingress of water, dust etc. into the housing interior through the heat transfer space is prevented. The wall may be substantially tubular or define a substantially tubular member in which at least part of the heat transfer member is located and supported. Parts of the heat transfer member such as the first and second ends may be located outside the tubular member (i.e., outside the heat transfer space). The wall may be made of a plastics material, for example.

[0032] The at least one air opening may be sealed by an air-permeable cover, e.g., by a hydrophobic membrane or similar. The air-permeable cover will allow heated air to flow out of the heat transfer space and cooler air to flow into the heat transfer space but will prevent the ingress of water, dust etc. If water or dust enters into and subsequently remains in the heat transfer space it will interfere with the air flow through the heat transfer space, thereby reducing the efficiency of the heat exchange.

[0033] The housing may include a first end adapted to receive, in use, an aerosol generating article with a mouthpiece through which aerosol is inhaled by a user, and a second end opposite the first end. The heat exchanger may be located between the coil and the second end. This means that the heat exchanger is located below the coil when the aerosol generating device is being held upright by the user - i.e., with the first end pointing upwards. This may help to improve the natural convection of the primary heat transfer fluid around the closed-loop heat transfer circuit because the heated primary heat transfer fluid will flow upwards as its density decreases. It will be understood that the coil will not normally be used for wireless charging with the aerosol generating device in this particular orientation, but the charging assembly may be used to transfer heat generated by other components such as the energy storage device if the coil is heat coupled thereto. Locating the heat exchanger below the coil when the aerosol generating device is being held upright by the user may therefore help to improve the natural convection at a time when heat is being generated by other heat-coupled components - e.g., when the energy storage device is supplying power to generate an aerosol for inhalation by the user. Improving the natural convection of the primary heat transfer fluid around the closed-loop heat transfer circuit will make the transfer of heat to the outside of the housing more efficient.

[0034] According to a third aspect of the present disclosure, there is provided an aerosol generating device comprising a charging assembly that comprises a first electrical connector having a collar that is fixedly connected around the first end of the coil and a solder tab that optionally includes an opening, and a second electrical connector having a collar that is fixedly connected around the second end of the coil and a solder tab that optionally includes an opening. The aerosol generating device further comprises: an energy storage device; and a printed circuit board assembly (or PCBA) comprising: a printed circuit board comprising first and second charging terminals, and first and second energy storage device terminals, and a charging circuit comprising one or more electronic components mounted to the printed circuit board, wherein the charging circuit is electrically connected to the first and second charging terminals and the first and second energy storage device terminals; wherein the first electrical connector is electrically connected to the first charging terminal by a first wire electrically connected to the solder tab (e.g., received in the opening of the solder tab) of the first electrical connector, and the second electrical connector is electrically connected to the second charging terminal by a second wire electrically connected to the solder tab (e.g., received in the opening of the solder tab) of the second electrical connector; and wherein the energy storage device is electrically connected to the first and second energy storage device terminals.

[0035] The collar of the first electrical connector may be a clamp-fit around the first end of the coil. The collar of the second electrical connector may be a clamp-fit around the second end of the coil. This provides a reliable electrical and physical connection between the first and second electrical connectors and the ends of the coil.

[0036] The first wire may be physically and electrically connected to the solder tab of the first electrical connector by receiving one end through the opening and soldering it in place, or by simply soldering it to the solder tab. The second wire may be physically and electrically connected to the solder tab of the second electrical connector by receiving one end through the opening and soldering it in place, or by simply soldering it to the solder tab. The other end of each wire may be soldered to a respective solder point on the printed circuit board (e.g., at the respective charging terminal).

[0037] It will be understood that during wireless charging the electric current that is generated in the coil and supplied to the first and second charging terminals through the first and second wires will be an alternating current. The first and second wires may comprise litz wire to mitigate against skin effect.

[0038] The energy storage device may be electrically connected to the first and second energy storage device terminals by a pair of wires. An end of each wire may be soldered to a respective solder point on the printed circuit board (e.g., at the respective energy storage device terminal).

[0039] According to a fourth aspect of the present disclosure, there is provided a method of circulating heat transfer fluid around the closed-loop heat transfer circuit of the charging assembly described above, by natural convection, to transfer heat away from the coil and / or any heat-generating component that is heat coupled to the coil. Such a heat-generating component may be an energy storage device such as a rechargeable lithium-ion secondary battery, for example.

[0040] The aerosol generating device may be adapted to receive, in use, an aerosol generating article.

[0041] The aerosol generating article may be received in a body or housing of the aerosol generating device, for example. The aerosol generating article may be removably received in the body or housing. The aerosol generating article may be of any suitable type and may include an aerosol generator adapted to heat aerosol generating material to generate an aerosol for inhalation by a user. The aerosol generator may include a heater. A heater may alternatively be part of the aerosol generating device.

[0042] The aerosol generator may be adapted to heat aerosol generating material. The aerosol generating material may be a liquid which may be stored in the aerosol generating article. The liquid aerosol generating material may soak into a wick (e.g., a cotton wick) and is then heated by the heater to produce a vapour that cools and condenses to form an aerosol that may then be inhaled. The wick may be omitted in some cases and the liquid aerosol generating material may be directly stored in a cavity of the aerosol generating article. The aerosol generating article may be formed as an integrated component (or “pod”) that includes a liquid store, a liquid transfer element or wick, and a heater. One or more electrical contacts may also be provided to establish an electrical connection between the heater and the energy storage device.

[0043] The aerosol generating material may comprise any type of solid or semi-solid material. Example types of aerosol generating solids include powder, granules, pellets, shreds, strands, particles, gel, strips, loose leaves, cut filler, porous material, foam material or sheets. The aerosol generating material may comprise plant derived material and in particular, may comprise tobacco. It may advantageously comprise reconstituted tobacco, for example including tobacco and any one or more of cellulose fibres, tobacco stalk fibres and inorganic fillers. The solid or semi-solid aerosol generating material may be heated by a heater that is provided as part of the aerosol generating article or the aerosol generating device - e.g., arranged adjacent to a heating space or chamber of the aerosol generating device that is adapted to receive the aerosol generating article in use.

[0044] The aerosol generating material may comprise an aerosol-former. Examples of aerosol-formers include polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. Typically, the aerosol generating material may comprise an aerosolformer content of between approximately 5% and approximately 50% on a dry weight basis. In some embodiments, the aerosol generating material may comprise an aerosol -form er content of between approximately 10% and approximately 22% on a dry weight basis, and possibly approximately 15% on a dry weight basis.

[0045] The aerosol generating device may be adapted to heat the aerosol generating material or substrate, without burning the aerosol generating material, to volatise at least one component of the aerosol generating material and thereby generate a heated vapour which cools and condenses to form an aerosol for inhalation by a user of the aerosol generating device. The volatile compounds released from the aerosol generating material may include nicotine or flavour compounds such as tobacco flavouring.

[0046] In general terms, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour may be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

[0047] When the aerosol generating material is depleted, the aerosol generating article may be removed from the aerosol generating device and a new article may be inserted.

[0048] The aerosol generating article may include a mouthpiece through which the generated aerosol may be inhaled.

[0049] Brief Description of the Drawings

[0050] Figure 1 is a diagrammatic view of an aerosol generating system with an aerosol generating device and an aerosol generating article;

[0051] Figure 2 is a diagrammatic view of the aerosol generating system of Figure 1 without the housing;

[0052] Figure 3 is a diagrammatic view of a charging assembly;

[0053] Figures 4 to 7 are diagrammatic detail views of the charging assembly of Figure 3;

[0054] Figure 8 is a diagrammatic view of part of the charging assembly of Figure 3 without a tubular wall that defines a heat transfer space;

[0055] Figure 9A is a diagrammatic front view of a charging assembly of Figure 3 without the tubular wall;

[0056] Figure 9B is a diagrammatic side view of the charging assembly of Figure 9A;

[0057] Figure 9C is a diagrammatic top view of the charging assembly of Figure 9A; and Figure 10 is a diagrammatic view of an alternative aerosol generating device with air openings are provided in the bottom end of the device housing.

[0058] Detailed Description of Embodiments

[0059] Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.

[0060] Referring initially to Figures 1 and 2 there is shown diagrammatically an example of an aerosol generating system 1. The aerosol generating system 1 comprises an aerosol generating device 2 and an aerosol generating article 4 for use with the aerosol generating device 2. The aerosol generating device 2 comprises a body or housing 6 and is sized to be comfortably held by a user unaided, in a single hand.

[0061] The aerosol generating device 2 includes a printed circuit board assembly (PCBA) 8, an energy storage device (e.g., a rechargeable battery 10), and a charging assembly 12.

[0062] The aerosol generating article 4 includes an aerosol generator 14 adapted to heat aerosol generating material (not shown) to generate an aerosol for inhalation by a user. The aerosol may be inhaled by a user through a mouthpiece 16 of the aerosol generating article 4.

[0063] The aerosol generating article 4 is received in an opening 18 in the upper end of the body or housing 6.

[0064] In Figures 1 and 2, the aerosol generating article 4 is shown as a cartridge (or “pod”). In another arrangement, the aerosol generating article may be a stick that looks like a conventional cigarette, for example. An aerosol generator may be attached to or embedded in such a stick-like aerosol generating article, or it may be formed as part of the aerosol generating device. Referring to Figures 3 to 8 and Figures 9 A to 9C, the charging assembly 12 includes a tubular coil 20 that is made of an electrically conductive material such as copper alloy. The coil 20 is a receiving coil for wireless inductive charging of the battery 10.

[0065] The coil 20 has a first end 20a that defines a fluid inlet and a second end 20b that defines a fluid outlet. The first and second ends 20a, 20b are electrically connectable to the battery 10 by means of a charging circuit.

[0066] The charging circuit is implemented by one or more electronic components that are mounted to the printed circuit board of a charging PCBA 22. In particular, a charging integrated circuit (IC) 22a may be mounted to the printed circuit board and electrically connected to both the coil 20 and the battery 10. The printed circuit board includes a pair of charging terminals U+, U- and a pair of battery terminals B+, B- that are electrically connected to the charging IC 22a by one or more electrically conductive paths formed on one or more surfaces of the printed circuit board. Alternatively, the charging IC 22a may be mounted to the other surface of the charging PCBA 22. The charging IC 22a may be integrated with one or more other electronic components such as a microcontroller unit, for example, to form a single “chip”.

[0067] The charging assembly 12 includes a first electrical connector 24 and a second electrical connector 26. The first electrical connector 24 is shown in more detail in Figures 5 and 6 and includes a collar 24a that is fixedly connected around the first end 20a of the coil 20 (i.e., by a clamp-fit) and a solder tab 24b that includes an opening 24c. The second electrical connector 26 is formed in the same way and has a collar that is fixedly connected around the second end 20b of the coil 20 (i.e., by a clamp fit) and a solder tab that includes an opening. An end of a first wire 28 is received through the opening 24c of the first electrical connector 24 and is soldered to the solder tab 24b. An end of a second wire 30 is received through the opening of the second electrical connector 26 and is soldered to the solder tab. The other end of the first and second wires 28, 30 is electrically connected to a respective charging terminal U+, U-. The first and second wires 28, 30 may be litz wires to mitigate skin effect. Although not shown, the battery 10 is electrically connected by a pair of wires to the battery terminals B+, B-. The electric current that is generated by the coil 20 during wireless charging may therefore be supplied to the charging IC 22a and then used to charge the battery 10. As shown the first and second wires 28, 30 are electrically connected to the first and second electrical connectors 24, 26 by means of respective openings in the solder tabs. Put another way, a through-hole mount technology is used to electrically connect the first and second wires 28, 30 to the first and second electrically connectors 24, 26. Alternatively, a surface mount technology may be used where at least one of the first and second wires 28, 30 is directly connected to a surface of the corresponding electrical connector without the need for an opening, e.g., where the wire is simply soldered to the solder tab.

[0068] The charging assembly 12 includes a tubular heat transfer member 32 that is arranged in a serpentine path with a plurality of bends or turns. Each individual bend or turn also follows a serpentine path as shown. The heat transfer member 32 is made of an electrically conductive material such as copper alloy and its serpentine construction maximises the surface area that is available for heat transfer.

[0069] The heat transfer member 32 has a first end 32a that defines a fluid inlet and second end 32b that defines a fluid outlet. The fluid outlet of the heat transfer member 32 is fluidly connected to the fluid inlet of the coil 20 by a tubular first fluid connector 34. The fluid outlet of the coil 20 is fluidly connected to the fluid inlet of the heat transfer member 32 by a tubular second fluid connector 36. The first and second fluid connectors 34, 36 are made of a plastics or synthetic polymer material, for example, and function as electrical insulators. Although only the first fluid connector 34 is shown in detail in Figure 7, it will be understood that the second fluid connector 36 has a similar construction but has a longer length because the distance between the fluid outlet of the coil 20 and the fluid inlet of the heat transfer member 32 is greater. The first and second fluid connectors 34, 36 are flexible and this allows for relative movement as a result of the thermal expansion of the coil 20 and / or the heat transfer member 32. The first and second fluid connectors 34, 36 may also act as pressure release valves in case of excessive pressure in the closed-loop heat transfer circuit. The first and second fluid connectors 34, 36 may also make it easier to assemble or manufacture the charging assembly 12 and make it easier to assemble the charging assembly 12 into the aerosol generating device 2. The first and second fluid connectors 34, 36 are connected to the coil 20 and the heat transfer member 32 using a suitable adhesive such as food-grade silicone adhesive, for example.

[0070] The first and second fluid connectors 34, 36 may be omitted if the heat transfer member 32 is made of an electrically non-conductive material. In this case, the ends 20a, 20b of the coil 20 may be connected directly to the ends 32a, 32b of the heat transfer member 32.

[0071] The coil 20 between the first and second ends 20a, 20b comprises a plurality of turns arranged substantially in a common plane. This is seen most clearly in Figure 9B. The heat transfer member 32 is not arranged in this common plane - Figures 9B and 9C show that the bends or turns of the heat transfer member 32 are arranged substantially in a plane that is substantially perpendicular to the common plane of the coil 20. Put another way, the bends or turns of the heat transfer member 32 are spaced apart along a direction that is substantially normal to the common plane of the coil 20. This will ensure that an electric current is not generated in the heat transfer member 32 during wireless charging of the coil 20.

[0072] The bends or turns of the heat transfer member 32 extend through a tubular wall 38 that defines a heat transfer space 40. The tubular wall 38 is made of a plastics material. Internal walls divide the heat transfer space 40 into a plurality of passages as shown. The internal walls are also made of a plastics material.

[0073] The open ends of the tubular wall 38 are aligned with air openings 42 that are provided in the housing 6 of the aerosol generating device 2. One air opening 42 is shown in Figure 1 and it will be understood that another is formed in the opposite side of the housing 6. The tubular wall 38 is sealed or otherwise fixedly connected to the housing 6 so that the heat transfer space 40 is separated from the remainder of the housing interior. The tubular wall 38 may be sealed to the housing 6 using a glue seal or an O-ring, for example. Heated air in the heat transfer space 40 cannot flow into the housing interior. The ingress of water, dust etc. into the housing interior through the heat transfer space 40 is also prevented.

[0074] In Figures 8 and 9 A to 9C the tubular wall 38 has been omitted so that the heat transfer member 32 may be seen more clearly.

[0075] A primary heat transfer fluid (e.g., propylene glycol or other suitable dielectric liquid) circulates around a closed-loop heat transfer circuit that is defined by the coil 20, the heat transfer member 32 and the first and second fluid connectors 34, 36. The primary heat transfer fluid is circulated by natural convection (or “free convection”) as described above.

[0076] Circulating the primary heat transfer fluid around the closed-loop heat transfer circuit will transfer heat away from the coil 20 during wireless charging. More particularly, the heat generated by the coil 20 during wireless charging is transferred into the primary heat transfer fluid - thereby cooling the coil 20. The heat is then transferred from the primary heat transfer fluid to the air in the heat transfer space 40 - thereby cooling the primary heat transfer fluid. Heated air will flow out of the heat transfer space 40 through an air opening (e.g., the air opening 42 shown in Figure 1) and cool air from outside the housing 6 will flow into the heat transfer space 40 through the same or another air opening (e.g., the air opening not shown in Figure 1, but which is formed in the other side of the housing 6). Air may therefore flow through the heat transfer space 40 past the turns or bends of the heat transfer member 32 for efficient heat exchange. In this way, heat is removed from the interior of the housing 6 of the aerosol generating device 2. This may allow for faster wireless charging of the battery 10 because it is less likely that the coil 20 will overheat. Electrical parameters of the coil (e.g., impedance) are maintained in a preferred range - it will be understood that such electrical parameters vary with temperature and may reduce wireless charging efficiency if the temperature of the coil increases significantly. The amount of heat that is dissipated into the housing 6 is also reduced. The coil 20 is heat coupled with the battery 10. For example, the coil 20 is positioned adjacent the battery 10 as shown in Figures 2 and 10. Heat generated by the battery 10 during normal operation of the aerosol generating device 2 may be transferred away from the battery 10 by circulating the primary heat transfer fluid around the closed- loop heat transfer circuit. More particularly, the heat generated by the battery 10 is transferred into the coil 20 and the primary heat transfer fluid - thereby cooling the battery 10. The heat is then transferred from the primary heat transfer fluid to the air in the heat transfer space 40 by the heat transfer member 32 - thereby cooling the primary heat transfer fluid. This may allow for better performance of the battery 10 and may extend battery lifetime. The amount of heat that is dissipated into the housing 6 is also reduced.

[0077] The charging assembly 12 may be used to transfer heat away from the battery 10 when the coil 20 is not being used for wireless charging - i.e., when the coil 20 itself is not generating heat. The charging assembly 12 may also be used to transfer heat away from the battery 10 when the coil 20 is being used for wireless charging - i.e., when both the coil 20 and the battery 10 are generating heat at the same time.

[0078] It should be noted that no external kinetic or electrical energy is needed to operate the heat exchanger of the charging assembly 12. As described above, the density differences of the primary heat transfer fluid due to temperature gradients results in circulation of the primary heat transfer fluid around the closed-loop heat transfer circuit. Once temperature gradients are caused by local heating of the primary heat transfer fluid in the coil 20, the primary heat transfer fluid will be automatically circulated around the closed-loop heat transfer circuit by natural convection. The coil 20 and any components that are heat coupled to the coil 20 are therefore cooled automatically without the need for any additional kinetic or electrical energy whenever heat is generated inside the housing of the aerosol generating device 2.

[0079] The heat transfer member 32 is located between the coil 20 and the bottom end of the housing. This means that the heat transfer member 32 is located below the coil 20 when the aerosol generating device 2 is being held upright by the user - i.e., with the mouthpiece 16 pointing upwards. This may help to improve the natural convection of the primary heat transfer fluid around the closed-loop heat transfer circuit because the heated primary heat transfer fluid will flow upwards as its density decreases. Locating the heat transfer member 32 below the coil 20 when the aerosol generating device 2 is being held upright by the user may therefore help to improve the natural convection at a time when heat is being generated by the battery 10 - i.e., when the battery 10 is supplying power to generate an aerosol for inhalation by the user. The natural convection may be assisted by gravity. Improving the natural convection of the primary heat transfer fluid around the closed-loop heat transfer circuit will make the transfer of heat to the outside of the housing 6 more efficient.

[0080] The air openings (e.g., the air opening 42) may be sealed by an air-permeable cover, e.g., by a hydrophobic membrane or similar. The air-permeable cover will allow heated air to flow out of the heat transfer space 40 and cooler air to flow into the heat transfer space 40 but will prevent the ingress of water, dust etc. If water or dust enters into and subsequently remains in the heat transfer space 40 it will interfere with the air flow through the heat transfer space 40, thereby reducing the efficiency of the heat exchange.

[0081] Figure 10 shows an alternative aerosol generating device where air openings 44 are provided in the bottom end of the housing 6. It can also be seen that the heat transfer member 32 is located in a heat transfer space 40 that is fluidly connected to the air openings 44 through the interior of the housing 6. Heated air may flow from the heat transfer space 40 and out of the housing 6 through the air openings 44. Cooler air may flow from outside the housing 6 to the heat transfer space 40.

[0082] Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments. Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

Claims

Claims1. A charging assembly (12) for an aerosol generating device (2), the charging assembly (12) comprising: an electrically conductive, tubular, receiving coil (20) for wireless inductive charging of an energy storage device (10), the coil (20) comprising a first end (20a) that defines a fluid inlet and a second end (20b) that defines a fluid outlet, wherein the first and second ends (20a, 20b) are electrically connectable to the energy storage device (10) by means of a charging circuit; a heat exchanger comprising a tubular heat transfer member (32) arranged in a heat transfer space (40) adapted to receive a secondary heat transfer fluid, the heat transfer member (32) comprising a first end (32a) that defines a fluid inlet and a second end (32b) that defines a fluid outlet, wherein the fluid inlet of the heat transfer member (32) is fluidly connected to the fluid outlet of the coil (20) and the fluid outlet of the heat transfer member (32) is fluidly connected to the fluid inlet of the coil (20) to define a closed-loop heat transfer circuit; and a primary heat transfer fluid in the closed-loop heat transfer circuit.

2. A charging assembly (12) according to claim 1, wherein the heat transfer member (32) is made of an electrically conductive material, and wherein the fluid outlet of the heat transfer member (32) is fluidly connected to the fluid inlet of the coil (20) by an electrically non-conductive tubular first fluid connector (34) and the fluid inlet of the heat transfer member (32) is fluidly connected to the fluid outlet of the coil (20) by an electrically non-conductive tubular second fluid connector (36).

3. A charging assembly (12) according to claim 1, wherein the heat transfer member is made of an electrically non-conductive material.

4. A charging assembly (12) according to any preceding claim, wherein the inner diameter of the coil (20) is less than the inner diameter of the heat transfer member (32).

5. A charging assembly (12) according to any preceding claim, wherein the heat transfer member (32) follows a serpentine path.

6. A charging assembly (12) according to any preceding claim, further comprising a first electrical connector (24) having a collar (24a) that is fixedly connected around the first end (20a) of the coil (20) and a solder tab (24b) that optionally includes an opening (24c), and a second electrical connector (26) having a collar that is fixedly connected around the second end (20b) of the coil (20) and a solder tab that optionally includes an opening.

7. A charging assembly (12) according to any preceding claim, wherein the coil (20) between the first and second ends (20a, 20b) comprises a plurality of turns arranged substantially in a common plane, and wherein the heat transfer member (32) is not arranged substantially in the common plane.

8. An aerosol generating device (2) comprising: a charging assembly (12) according to any preceding claim; a charging circuit electrically connected to the first and second ends (20a, 20b) of the coil (20) of the charging assembly (12); and an energy storage device (10) electrically connected to the charging circuit.

9. An aerosol generating device (2) according to claim 8, wherein the coil (20) is arranged adjacent the energy storage device (10) and is heat coupled to the energy storage device (10).

10. An aerosol generating device (2) according to claim 8 or claim 9, further comprising a housing (6) in which the charging assembly (12) and the energy storage device (10) are located, and wherein the housing (6) includes at least one air opening (42; 44) that is in fluid communication with the heat transfer space (40).

11. An aerosol generating device (2) according to claim 10, wherein the heat transfer space (40) is sealed from the remainder of the housing interior.

12. An aerosol generating device (2) according to claim 10 or claim 11, wherein the at least one air opening (42; 44) is sealed by an air-permeable cover.

13. An aerosol generating device (2) according to any of claims 10 to 12, wherein the housing (6) includes a first end adapted to receive, in use, an aerosol generating article (4) with a mouthpiece (16) through which aerosol is inhaled by a user, and a second end opposite the first end, and wherein the heat exchanger is located between the coil (20) and the second end.

14. An aerosol generating device (2) comprising: a charging assembly (12) according to claim 6; an energy storage device (10); and a printed circuit board assembly (22) comprising: a printed circuit board comprising first and second charging terminals, and first and second energy storage device terminals, and a charging circuit comprising one or more electronic components mounted to the printed circuit board, wherein the charging circuit is electrically connected to the first and second charging terminals and the first and second energy storage device terminals; wherein the first electrical connector (24) is electrically connected to the first charging terminal by a first wire (28) electrically connected to the solder tab (24b) of the first electrical connector (24), and the second electrical connector (26) is electrically connected to the second charging terminal by a second wire (30) electrically connected to the solder tab of the second electrical connector (26); and wherein the energy storage device (10) is electrically connected to the first and second energy storage device terminals.

15. A method of using the charging assembly (12) according to any of claims 1 to 7, to transfer heat away from the coil (12) and / or any heat-generating component (10) that is heat coupled to the coil (20), by circulating the primary heat transfer fluid around the closed-loop heat transfer circuit by natural convection.

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