Power management method and system for a battery powered aerosol-generating device

Abstract

A power management method and system for a battery powered aerosol-generating device is disclosed. A method for controlling power supplied to an aerosol-generating element of an aerosol-generating device is provided, the aerosol-generating device comprising an aerosol-generating element, a control unit and a battery for delivering power to the aerosol-generating element and the control unit, the control unit being configured to adjust a duty cycle of a current supplied from the battery to the aerosol-generating element, wherein the method comprises the steps of: measuring at least one first property of the battery using a measurement unit, wherein the at least one battery first property comprises a temperature of the battery; and adjusting a value of the duty cycle using the control unit based on a predetermined rule, the predetermined rule outputting a value of the duty cycle based on the measured at least one battery property. By controlling the duty cycle of the current supplied from the battery in this way, it is possible to use as high a duty cycle as possible, while maintaining the voltage at the control unit at or above a minimum operating voltage.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880015974.3, filed on March 9, 2018, entitled "Power Management Method and System for Battery-Powered Aerosol Generation Device". Technical Field

[0002] This invention relates to a battery-powered aerosol generating apparatus, and more particularly to a method and system for controlling the power supply to an aerosol generating element, which improves the reliability of the apparatus under different operating conditions. Background Technology

[0003] Typically, battery-powered aerosol generating devices include aerosol generating elements, such as resistance heating elements, which are connected to the battery.

[0004] When initially starting an aerosol generator, it is crucial to minimize the time it takes for the device to deliver the aerosol. This is especially important for devices that generate aerosols for inhalation; if the delivery time for the first inhalation is too long, the user will become frustrated. In devices using resistance heaters, this means increasing the heater temperature as quickly as possible.

[0005] However, there are potential difficulties in simply delivering maximum power to the aerosol generating element at the outset. Aerosol generating devices typically include a microcontroller unit (MCU) and various electronic components that require a minimum voltage to operate correctly. Below this voltage, proper operation cannot be guaranteed. This is especially true for MCUs. But delivering maximum power from a battery, particularly when the battery is cooled, can result in insufficient voltage for the MCU.

[0006] It is well known that drawing high current from a battery reduces its output voltage. This is due to the battery's internal resistance. It is also known that the battery's internal resistance is higher at low temperatures, thus limiting the maximum discharge current. Furthermore, for any given output battery current, the battery's output voltage is lower at low temperatures. And in cases where the aerosol generating element is a resistance heater with a positive temperature coefficient, the heater's resistance will be lowest before startup and will increase with temperature, resulting in a significant voltage drop across the battery's internal resistance.

[0007] For these reasons, applying maximum power at the start may cause the device to stop operating, as the output voltage from the battery drops below the minimum voltage required by the MCU.

[0008] It will need to be able to draw maximum power from the battery to enable the device to operate fully in the shortest amount of time, while ensuring that the output battery voltage is maintained above a minimum threshold voltage, thereby ensuring the correct operation of the MCU. Summary of the Invention

[0009] To regulate the operation of the aerosol generating device, the battery can be dynamically connected to the aerosol generating element, allowing the duty cycle of the current and voltage applied to the aerosol generating element to be varied.

[0010] In a first aspect, a method is provided for controlling power supplied to an aerosol generating element of an aerosol generating apparatus, the aerosol generating apparatus including an aerosol generating element, a control unit, and a battery for delivering power to the aerosol generating element and the control unit, the control unit being configured to adjust the duty cycle of a current supplied from the battery to the aerosol generating element, wherein the method includes the following steps:

[0011] The battery is measured using a measuring unit; and

[0012] The control unit adjusts the duty cycle value based on a predetermined rule, which outputs the duty cycle value based on at least one measured battery characteristic.

[0013] By controlling the duty cycle of the current supplied from the battery in this manner, the highest possible duty cycle can be used while maintaining the voltage at or above the minimum operating voltage at the control unit. Predefined rules can be selected to ensure that the voltage at the control unit exceeds a threshold voltage.

[0014] At least one battery characteristic may include the battery's temperature. The battery's output voltage is affected by temperature because its internal resistance is also affected by temperature. A thermistor or other dedicated temperature sensor may be used to obtain a measure of the battery's temperature. Alternatively, at least one battery characteristic may include a measure of the battery's age, such as a count of the number of charge and discharge cycles the battery has completed. The count of charge and discharge cycles may be recorded and stored in a memory within the aerosol generating device. Alternatively, at least one battery characteristic may include the battery's internal resistance or the battery's impedance. The battery's internal resistance may be measured using well-known techniques, such as the methods described in WO2014 / 029880. Battery impedance may be measured by injecting a small AC current into the battery and measuring the associated AC voltage.

[0015] Advantageously, the measurement and adjustment steps are performed periodically. When the battery discharges, it dissipates some heat due to its internal resistance. This may cause a decrease in internal resistance. The duty cycle can be adjusted periodically, for example, every 0.5 seconds, to account for the battery's reduced internal resistance. In this way, the duty cycle can start at a low level and gradually increase, while ensuring that the control unit receives sufficient voltage.

[0016] Advantageously, the predetermined rule defines multiple intervals of values ​​related to at least one characteristic of the battery, each interval being associated with a corresponding duty cycle value. The step of adjusting the duty cycle value includes outputting the duty cycle value associated with the interval, which contains the measured value of at least one battery characteristic. The intervals of values ​​related to at least one characteristic of the battery may be sequential. The intervals of values ​​related to at least one characteristic of the battery may be non-overlapping.

[0017] For example, in one embodiment, at least one characteristic of the battery is temperature, and predetermined rules include the following ranges and associated duty cycle values:

[0018] 1 / If the battery temperature is between -10°C and -5°C, then use a duty cycle of 10%.

[0019] 2 / If the battery temperature is between -5℃ and 0℃, then use a duty cycle of 20%.

[0020] 3 / If the battery temperature is between 0°C and 5°C, then use a duty cycle of 30%.

[0021] 4 / If the battery temperature is between 5°C and 10°C, then use a duty cycle of 40%.

[0022] 5 / If the battery temperature is between 10°C and 15°C, then use a duty cycle of 50%.

[0023] 6 / If the battery temperature is between 15°C and 20°C, then use a duty cycle of 60%.

[0024] 7 / If the battery temperature is above 20°C, then use any desired duty cycle.

[0025] In the case of handheld devices, it is expected that the battery temperature will rise during use due to heat generated inside the battery and by one or more heaters in the device, as well as the user's body heat being transferred to the battery as they hold the device.

[0026] The method may further include the steps of measuring at least one second characteristic of the aerosol generating device and selecting a duty cycle value based on a predetermined sub-rule and the measured value of at least one second characteristic of the aerosol generating device, wherein a predetermined sub-rule is selected from a group of predetermined sub-rules based on the measured at least one first characteristic of the battery.

[0027] The steps of periodically measuring at least one secondary characteristic and selecting a duty cycle value are performed. The duty cycle can be adjusted periodically, for example, every 0.5 seconds, to account for the constantly changing values ​​of the secondary characteristic of the aerosol generating element. In this way, the duty cycle can start at a low level and gradually increase, while ensuring that the control unit receives sufficient voltage.

[0028] At least one second characteristic of the aerosol generating device may include the resistance of the aerosol generating element. The resistance of the aerosol generating element may change during use because it may be temperature-dependent. The aerosol generating element may be a resistance heater. At least one second characteristic of the aerosol generating device may include the temperature of the resistance heater. The resistance of the resistance heater may depend on the temperature of the resistance heater. Depending on the composition of the resistance heater, as the resistance heater heats up, the resistance may increase, for example, causing a lower voltage drop across the internal resistance of the battery and thus allowing the use of a larger duty cycle.

[0029] At least one second characteristic differs from the battery's first characteristic. At least one second characteristic may include a measure of the battery's age, such as a count of the number of charge and discharge cycles the battery has completed. The count of charge and discharge cycles may be recorded and stored in a memory within the aerosol generating device. Alternatively, at least one second characteristic may include the battery's internal resistance or the battery's impedance. Alternatively, if the battery's temperature is not used as the battery's first characteristic, then the battery's temperature may be used as at least one second characteristic.

[0030] The steps of measuring at least one second characteristic and selecting a duty cycle value can be performed periodically until at least one second characteristic reaches a target value. In the example of a resistance heater, it may be necessary for the heater to reach a target temperature or a target temperature range for generating the desired aerosol, but not exceeding the target. When the target temperature is reached, it is necessary to maintain the temperature rather than maximizing the duty cycle of the current supplied to the heater. Different duty cycles can be used for the purpose of regulating the temperature of the heater. The higher the duty cycle, the higher the average current delivered from the battery to the heating element, and therefore the higher the temperature of the heating element. Of course, decreasing the duty cycle allows for the opposite, such as lowering the temperature of the heater.

[0031] The method may include monitoring the time since the device was started, and if the target temperature is not reached within a predetermined time, then canceling the start-up or deactivating the device.

[0032] The predefined sub-rule may define multiple intervals of values ​​relating to at least a second characteristic of the aerosol generating device, each interval being associated with a corresponding duty cycle value. The step of adjusting the duty cycle value using the control unit may include selecting an interval of measured values ​​encompassing at least one second characteristic of the aerosol generating device. The intervals of values ​​relating to at least a second characteristic of the aerosol generating device may be sequential. The intervals of values ​​relating to at least a second characteristic of the aerosol generating device may be non-overlapping.

[0033] For example, if the first characteristic of the battery is the battery temperature and the second characteristic of the aerosol generating device is the heating element resistance, and the battery temperature is determined to be -2°C within the second range given above, then the sub-rule for said temperature range could be:

[0034] 2.1 / ​​If the resistance of the heating element is between 0.8 and 1 ohm, then use a duty cycle of 20%.

[0035] 2.2 / If the resistance of the heating element is between 1 and 1.2 ohms, then use a duty cycle of 30%.

[0036] 2.3 / If the resistance of the heating element is between 1.2 and 1.4 ohms, then use a duty cycle of 40%.

[0037] 2.4 / If the resistance of the heating element is between 1.4 and 1.6 ohms, then use a duty cycle of 50%.

[0038] 2.5 / If the heating element resistance is between 1.6 and 1.8 ohms, then use a duty cycle of 60%.

[0039] 2.6 / If the resistance of the heating element is higher than 1.8 ohms, then use any desired duty cycle.

[0040] For each interval of values ​​relating to at least one characteristic of the battery in the predetermined rules, there may be different sub-rules.

[0041] The method may use other sub-rule levels based on other measured characteristics. Specifically, the method may include the steps of measuring a third characteristic of the battery or aerosol generating device and selecting a duty cycle value based on predetermined sub-rules and the measured value of at least one third characteristic of the aerosol generating device or battery, wherein predetermined sub-rules are selected from a group of predetermined sub-rules based on predetermined sub-rules, the measured value of the second characteristic, and at least one measured first characteristic of the battery. For each interval of the value of the second characteristic in the sub-rule, there may be a group of sub-rules that specify different ranges of the third characteristic associated with it. Other rule levels may be used in a rule hierarchy based on multiple measured characteristics.

[0042] The method may further include periodically measuring the output battery voltage, calculating the rate of decrease of the output battery voltage based on the measured output battery voltage, and reducing the duty cycle if the rate of decrease of the output battery voltage exceeds a threshold level. This is advantageous because it curbs or slows the decrease of the output battery voltage to a level that still ensures the control unit receives the minimum threshold voltage. For example, if, after the duty cycle of the current is increased according to a predetermined rule, it is determined that the rate of decrease of the output battery voltage will drop below the minimum operating voltage within only a few seconds before the resistance heater can reach the target temperature, then the duty cycle can be reduced by 5%. Different threshold levels for the rate of decrease of the output battery voltage may exist within the predetermined rule or sub-rule for each interval. The rate of decrease of the output battery voltage can be calculated periodically more frequently by measuring a first characteristic. The rate of decrease of the output battery voltage can be calculated periodically more frequently by measuring a second characteristic.

[0043] The threshold level for the rate of decrease of the output battery voltage can be set based on the initial output battery voltage. In one example, the threshold level for the rate of decrease of the output battery voltage can be limited by the minimum time it takes for the heater to increase its resistance to a specific value, such as 1.6 Ohms for a 3.2V battery, thus drawing 2A of current. The battery voltage should then not drop below its minimum value (e.g., 2.5V) before this minimum time. The minimum time can be set, for example, to 5 seconds. If the initial battery voltage is 3.2V, then the maximum rate of decrease of the battery voltage will be: (3.2V - 2.5V) / 5 = 0.14V / s. Alternatively, the threshold level for the rate of decrease of the output battery voltage can be specified as a set of values ​​independent of the initial output battery voltage, such as 0.5V / s.

[0044] The method may further include increasing the duty cycle if the rate of decrease of the output battery voltage exceeds a threshold within a predetermined number of measurement cycles of the output battery voltage.

[0045] The method may include revoking or deactivating the device when the duty cycle needs to be reduced to below the minimum duty cycle.

[0046] In a second aspect, an aerosol generating apparatus is provided, comprising:

[0047] Aerosol generating element;

[0048] Control unit;

[0049] A battery for delivering current to the aerosol generating element and the control unit; and

[0050] A measuring unit connected to the control unit is used to measure at least one first characteristic of the battery;

[0051] The control unit is configured to adjust the duty cycle of the current delivered from the battery to the aerosol generating element based on a predetermined rule, which outputs the duty cycle value based on the at least one battery characteristic measured by the measuring unit.

[0052] The aerosol generating device may include non-volatile memory. The non-volatile memory may be part of the control unit. The non-volatile memory may store predetermined rules.

[0053] The control unit can be configured to implement the method according to the first aspect of the invention. Specifically, the control unit can be configured to use sub-rules as described with respect to the first aspect of the invention. The control unit can be configured to measure the rate of decrease of the output battery voltage as described with respect to the first aspect of the invention.

[0054] The control unit may include a switch. The control unit may be configured to adjust the duty cycle by operating the switch to turn the supply of current to the aerosol generating element on and off. The switch may be a transistor, such as a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0055] At least one characteristic of the battery may be battery temperature. The measuring unit may include a temperature sensor. Alternatively, at least one battery characteristic may include a measure of battery age, such as a count of the number of charge and discharge cycles the battery has completed. The count of charge and discharge cycles may be recorded and stored in a memory within the aerosol generating apparatus. Alternatively, at least one battery characteristic may include the battery's internal resistance or the battery's impedance. The battery's internal resistance and impedance may be measured using well-known techniques, such as the methods described in WO2014 / 029880.

[0056] As used herein, an 'aerosol generating apparatus' relates to an apparatus that interacts with an aerosol-forming matrix to generate aerosols. The aerosol-forming matrix may be part of an aerosol-generating article. An aerosol generating apparatus may be an apparatus that interacts with the aerosol-forming matrix of an aerosol-generating article to generate aerosols that can be directly inhaled into a user's lungs through their mouth. The aerosol-generating element may be configured to heat or otherwise atomize the aerosol-forming matrix to form aerosols. The aerosol-forming matrix may be wholly or partially contained within the apparatus.

[0057] The aerosol forming matrix can be a solid aerosol forming matrix. Alternatively, the aerosol forming matrix can be liquid or may include both solid and liquid components. The aerosol forming matrix may include tobacco-containing material containing volatile tobacco flavor compounds released from the matrix upon heating. Alternatively, the aerosol forming matrix may include non-tobacco material. The aerosol forming matrix may further include an aerosol forming agent. Examples of suitable aerosol forming agents are glycerol and propylene glycol.

[0058] If the aerosol forming matrix is ​​a solid aerosol forming matrix, then the solid aerosol forming matrix may include one or more of the following: powder, granules, pellets, fragments, strips, bars, or sheets, wherein the material contains one or more of herbaceous plant leaves, tobacco leaves, tobacco ribs, reconstituted tobacco, homogenized tobacco, extruded tobacco, cast leaf tobacco, and expanded tobacco. The solid aerosol forming matrix may be in a loose form or may be provided in a suitable container or tube. If desired, the solid aerosol forming matrix may contain additional tobacco or non-tobacco volatile aroma compounds that are released upon heating of the matrix. The solid aerosol forming matrix may also contain capsules, such as those containing additional tobacco or non-tobacco volatile aroma compounds, and such capsules may melt during heating of the solid aerosol forming matrix.

[0059] As needed, the solid aerosol forming matrix can be provided on or embedded in a thermally stable carrier. The carrier can be in the form of powder, granules, microspheres, fragments, strips, bars, or sheets. Alternatively, the carrier can be a tubular carrier with a thin layer of solid matrix deposited on its inner surface, its outer surface, or both. This tubular carrier can be formed from, for example, paper or paper-like materials, nonwoven carbon fiber pads, low-mass open-mesh metal wire mesh or perforated metal foil, or any other thermally stable polymer matrix.

[0060] Solid aerosol forming matrix can be deposited on the surface of a carrier in the form of, for example, sheets, foams, gels, or slurries. The solid aerosol forming matrix can be deposited on the entire surface of the carrier, or alternatively, it can be deposited in a patterned manner to provide uneven fragrance delivery during use.

[0061] Although a solid aerosol forming matrix has been mentioned above, those skilled in the art will appreciate that other embodiments may use other forms of aerosol forming matrix. For example, the aerosol forming matrix may be a liquid aerosol forming matrix. If a liquid aerosol forming matrix is ​​provided, the aerosol generating apparatus preferably includes components for retaining the liquid. For example, the liquid aerosol forming matrix may be retained in a container. Alternatively, the liquid aerosol forming matrix may be absorbed into a porous support material. The porous support material may be made of any suitable absorbent plug or absorbent, such as foamed metal or plastic materials, polypropylene, polyester, nylon fibers, or ceramics. The liquid aerosol forming matrix may be retained in the porous support material before use of the aerosol generating apparatus, or alternatively, the liquid aerosol forming matrix material may be released into the porous support material during use or just before use. For example, the liquid aerosol forming matrix may be provided in a capsule. The capsule shell preferably melts upon heating and releases the liquid aerosol forming matrix into the porous support material. The capsule may contain a combination of solid and liquid as needed. Alternatively, the carrier can be a nonwoven fabric or fiber bundle containing tobacco components. The nonwoven fabric or fiber bundle may include, for example, carbon fibers, natural cellulose fibers, or cellulose-derived fibers.

[0062] During operation, the aerosol-forming matrix can be completely contained within the aerosol generating device. In this case, the user can aspirate using the nozzle of the aerosol generating device. Alternatively, during operation, the aerosol-forming article containing the aerosol-forming matrix can be partially contained within the aerosol generating device. In this case, the user can directly aspirate using the aerosol-forming article.

[0063] The shape of the aerosol-forming article can be substantially cylindrical. The aerosol-forming article can be substantially elongated. The aerosol-forming article can have a certain length and a circumference substantially perpendicular to said length. The shape of the aerosol-forming matrix can be substantially cylindrical. The aerosol-forming matrix can be substantially elongated. The aerosol-forming matrix can also have a certain length and a circumference substantially perpendicular to said length.

[0064] The total length of the aerosol-forming article can be between approximately 30 mm and approximately 100 mm. The aerosol-forming article can have an outer diameter between approximately 5 mm and approximately 12 mm. The aerosol-forming article may include a filter plug. The filter plug may be located at the downstream end of the aerosol-forming article. The filter plug may be a cellulose acetate filter plug. In one embodiment, the length of the filter plug is approximately 7 mm, but it may have a length between approximately 5 mm and approximately 10 mm.

[0065] In one embodiment, the total length of the aerosol-forming article is approximately 45 mm. The aerosol-forming article may have an outer diameter of approximately 7.2 mm. Furthermore, the aerosol-forming matrix may have a length of approximately 10 mm. Alternatively, the aerosol-forming matrix may have a length of approximately 12 mm. Additionally, the diameter of the aerosol-forming matrix may be between approximately 5 mm and approximately 12 mm. The aerosol-forming article may include an outer packaging paper. Furthermore, the aerosol-forming article may include a separator between the aerosol-forming matrix and the filter plug. The separator may be approximately 18 mm, but may range from approximately 5 mm to approximately 25 mm.

[0066] The aerosol generating element can be a resistance heater. At least one secondary characteristic of the aerosol generating element can be the temperature or resistance of the resistance heater.

[0067] Resistance heaters may include resistive materials. Suitable resistive materials include, but are not limited to: semiconductors, such as doped ceramics, “conductive” ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic and metallic materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, platinum, gold, and silver. Examples of suitable metal alloys include stainless steel, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-titanium-zirconium alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, gold-containing and iron-containing alloys, as well as alloys based on nickel, iron, cobalt, stainless steel, etc. Superalloys based on iron-manganese-aluminum alloys. In composite materials, resistive materials can be embedded in insulating materials as needed, encapsulated by insulating materials, coated by insulating materials, or vice versa, depending on the energy transfer kinetics and desired external physicochemical properties.

[0068] Aerosol generation apparatus may include an internal resistance heater or an external resistance heater, or both, wherein “internal” and “external” refer to the aerosol forming matrix. The internal resistance heater may take any suitable form. For example, the internal resistance heater may take the form of a heating blade. Alternatively, the internal resistance heater may take the form of a sleeve or substrate with different conductive portions, or a resistive metal tube. Alternatively, the internal resistance heater may be one or more heating needles or rods penetrating the center of the aerosol forming matrix. Other alternatives include heating wires or filaments, such as nickel-chromium (Ni-Cr), platinum, tungsten, or alloy wires, or heating plates. The internal resistance heater may be deposited within or on a rigid carrier material, if desired. In one such embodiment, the resistance heater may be formed using a metal with a defined relationship between temperature and resistivity. In this exemplary apparatus, the metal may be formed as traces on a suitable insulating material, such as ceramic, and then sandwiched within another insulating material, such as glass. A heater formed in this manner can be used to heat and monitor the temperature of the heating element during operation.

[0069] The external resistance heater can take any suitable form. For example, it can take the form of one or more flexible heating foils on a dielectric substrate, such as polyimide. The flexible heating foil can be shaped to conform to the periphery of the substrate receiving cavity. Alternatively, the external heating element can take the form of a metal mesh, flexible printed circuit board, molded interconnect device (MID), ceramic heater, flexible carbon fiber heater, or can be formed on a suitable molded substrate using a coating technique such as plasma vapor deposition. The external resistance heater can also be formed using a metal with a defined relationship between temperature and resistivity. In this exemplary device, the metal can be formed as a trace between two layers of suitable insulating material. An external resistance heater formed in this way can be used to heat and monitor the temperature of the external heating element during operation.

[0070] Resistance heaters advantageously heat the aerosol-forming matrix by means of conduction. The heating element may be at least partially in contact with the matrix or a carrier on which the matrix is ​​deposited. Alternatively, heat from an internal or external heater may be conducted to the matrix by means of a thermally conductive element.

[0071] The battery can be a rechargeable battery. The battery can be a lithium-ion battery, such as a lithium-cobalt, lithium iron phosphate, lithium titanate, or lithium polymer battery. Alternatively, the battery can be another form of rechargeable battery, such as a nickel-metal hydride battery or a nickel-cadmium battery.

[0072] The measuring unit can be integrated with the battery, or it can be located on or in the battery casing.

[0073] The control unit may include a microcontroller unit (MCU). The control unit may be programmable. The control unit may include a switch connected in series with the aerosol generating element to the battery.

[0074] The device is preferably a portable or handheld device that can be comfortably held between the fingers of a single hand. The device may be substantially cylindrical in shape and have a length between 70 and 120 mm. The maximum diameter of the device is preferably between 10 and 20 mm. In one embodiment, the device has a polygonal cross-section and a protruding button formed on one face. In this embodiment, the diameter of the device from one flat face to the opposite flat face is between 12.7 and 13.65 mm; the diameter from one edge to the opposite edge (i.e., from the intersection of two faces on one side of the device to the corresponding intersection on the other side) is between 13.4 and 14.2 mm; and the diameter from the top of the button to the opposite bottom flat face is between 14.2 and 15 mm.

[0075] The aerosol generating device can be an electrically heated aerosol forming device.

[0076] In a third aspect of the invention, a computer program is provided that, when run on a programmable circuit in a control unit of an electrically operated aerosol generating apparatus, causes the programmable circuit to perform a method according to a first aspect of the invention, the aerosol generating apparatus including an aerosol generating element and a battery for delivering power to the aerosol generating element and the control unit. Attached Figure Description

[0077] Although this disclosure has been described with reference to various aspects, it should be understood that features described with respect to one aspect of this disclosure may be applied to other aspects of this disclosure.

[0078] Examples of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0079] Figure 1 This is a schematic illustration of an apparatus according to an embodiment of the present invention;

[0080] Figure 2 Explain the connection of the components of the apparatus involved in the method according to the present invention;

[0081] Figure 3 This describes a set of sub-rules according to embodiments of the present invention;

[0082] Figure 4 This is a flowchart illustrating the control process according to an embodiment of the present invention;

[0083] Figure 5 This is an additional control process used in embodiments of the present invention. Detailed Implementation

[0084] exist Figure 1 In the simplified representation, the components of an embodiment of the electrically heated aerosol generating apparatus 1 are shown. The elements of the electrically heated aerosol generating apparatus 1 are... Figure 1 It is not drawn to scale. In order to make Figure 1 For simplification, elements irrelevant to understanding this embodiment have been omitted.

[0085] An electrically heated aerosol generating device 1 includes a housing 10 and an aerosol forming matrix 12, such as an aerosol forming article (e.g., a cigarette). The aerosol forming matrix 12 is pushed into the housing 10 to be in thermal proximity to a heater 4. In this example, the heater is a blade extending into the aerosol forming matrix. The aerosol forming matrix 12 will release a series of volatile compounds at different temperatures. The release or formation of these smoke components can be avoided by controlling the maximum operating temperature of the heater below the release temperature of some of the volatile compounds. Typically, the aerosol forming matrix is ​​heated to a temperature between 250°C and 450°C. An electrical battery 2, such as a rechargeable lithium-ion battery, is located within the housing 10. A control unit 3 is connected to the heating element 2, the electrical battery 2, and a user interface 6, such as a button or display. For example, this type of system is described in EP2800486.

[0086] Control unit 3 controls the power supplied to heating element 4 so as to regulate its temperature by changing the duty cycle of the current. Figure 2 illustrate Figure 1 The connection of the battery, control unit and resistance heater in the device.

[0087] Battery 2 is described as an ideal battery 21 along with an internal resistor 22. The battery is connected to the resistive heater 4 via a control unit. The control unit includes a microprocessor unit (MCU) 20 and a switch 23. The MCU controls the operation of the switch to control the duty cycle of the current delivered to the heater 4. The MCU 20 includes non-volatile memory 27.

[0088] The device also includes a temperature sensor 25, which is positioned to measure the temperature of the battery 2. For example, the temperature sensor may be a thermistor for providing analog temperature measurements or a digital temperature sensor, such as the LM75ADP from NXP. The output of the temperature sensor 25 is connected to the MCU 20. The battery temperature measured by the temperature sensor 25 is used to control the operation of the switch 23 based on at least one rule stored in the non-volatile memory 27, as will be described.

[0089] The device can be started by the user using user interface 6. When the device is started, current is delivered from the battery to the heater through switch 23.

[0090] Ideally, the heater should rise to the target temperature as quickly as possible after startup, while ensuring the MCU receives sufficient voltage for proper functioning. Initially, as the battery cools, it will have relatively high internal resistance, meaning a larger proportion of the battery voltage will drop across this internal resistance compared to when the battery has heated up. This implies that a lower duty cycle is needed to supply current when the battery is cold to ensure the MCU receives at least the minimum operating voltage.

[0091] The voltage received by the MCU is also affected by the resistance of heater 4. The resistance of heater 4 will typically change during device operation as the heater heats up. The heater can be formed of a material whose resistance changes significantly with temperature, so that the heater's resistance can be used as a measure of the heater's temperature for heater temperature control. The heater in this example has a positive temperature coefficient, meaning that the heater's resistance increases as the heater temperature increases.

[0092] The MCU can be configured to measure the resistance of heater 4. This can be achieved by using a shunt resistor (with very low resistance) connected in series with heater 4. The current through the shunt resistor is also the current through the heater, which can be measured using an amplifier connected in parallel to the shunt resistor. The voltage across the heater can be measured directly, and the resistance of the heater is then calculated using Ohm's law. This is a well-known measurement technique.

[0093] The MCU controls the operation of the switch according to the rules stored in the MCU's memory. Figure 3 This describes an example of rule 30 that can be used by the MCU. This rule allows battery T... bat The measured temperature and heater R h The measured resistance is related to the output duty cycle. The rule comprises multiple sub-rules, each associated with a range of battery temperatures. These battery temperature ranges are sequential but do not overlap. Within each sub-rule, multiple duty cycles exist, each associated with a different range of heater resistance. These heater resistance ranges are sequential but do not overlap. To determine which duty cycle to use, the MCU first selects the sub-rule associated with the range of battery temperatures to which the measured battery temperature 31 belongs. Figure 3 In the example illustrated, this is range 2, covering temperatures from T2 to T3, as illustrated by dashed box 32. The MCU then selects a duty cycle from the sub-rules associated with range 2. The selected duty cycle is the duty cycle associated with the range of heater resistances to which the measured heater resistance 33 belongs. Figure 3 In the example shown, it is related to the resistance range R h5 To R h6 The associated duty cycle is DC8, as illustrated by dashed box 34. Therefore, the output from rule 30 is DC8, as shown by box 36.

[0094] Instead of using the heater resistor as specified in the rules, another parameter, such as the heater temperature, can be used. The device may include a temperature sensor located near the heater. The output of the temperature sensor will be connected to the MCU.

[0095] The number of ranges and sub-ranges can be selected according to specific design requirements and the construction of heater 4. Figure 4 The examples shown include four ranges for battery temperature and four ranges for heater resistance. In another embodiment, there are seven ranges for battery temperature, as follows:

[0096] 1 / -10℃ to -5℃

[0097] 2 / -5℃ to 0℃

[0098] 3 / 0℃ to 5℃.

[0099] 4 / 5℃ to 10℃.

[0100] 5 / 10℃ to 15℃.

[0101] 6 / 15℃ to 20℃.

[0102] 7 / Above 20℃.

[0103] Furthermore, there are six ranges for the heater resistance in each sub-rule, as follows:

[0104] 1 / 0.8 to 1 ohm

[0105] 2 / 1 to 1.2 ohms

[0106] 3 / 1.2 to 1.4 ohms

[0107] 4 / 1.4 to 1.6 ohms

[0108] 5 / 1.6 to 1.8 ohms

[0109] 6 / Above 1.8 ohms.

[0110] The duty cycle value associated with each range in each sub-rule should be selected to ensure that the MCU always receives the minimum operating voltage required for proper MCU function. If the battery temperature is below -10°C, then the device should be disabled.

[0111] A process is periodically performed to adjust the duty cycle of the current delivered to the heater, for example, every 0.5 seconds after the device is started, until the heater reaches the target temperature or target resistance. Therefore, a new sub-rule can be applied every 0.5 seconds, depending on changes in battery temperature and heater resistance.

[0112] If the heater does not reach the target temperature, such as 350°C, within a fixed time, such as 30 seconds, the heating process will stop. In this case, the battery cannot deliver sufficient power to the heater. This may be because the battery is old.

[0113] Figure 4 This is a flowchart illustrating an example control process using rules of the type described above. The device is started in step 40. In the first step 41, after startup, the battery temperature is measured. Next, in step 42, a duty cycle for the current is selected based on the battery temperature. At this stage, it is assumed that the heater resistance is at its maximum value before any current has been applied to the heater. In step 43, the MCU operates a switch according to the selected duty cycle to deliver current to the heater. This duty cycle is maintained for a predetermined period, e.g., 0.5 seconds. During this period, the heater resistance is measured in step 44. In step 45, the measured resistance is compared to a target resistance, corresponding to a target heater temperature. If the heater resistance is equal to or greater than the target resistance, the method ends at step 46. If the heater resistance is less than the target resistance, indicating that the heater has not yet reached the target temperature, the process returns to step 41, where the battery temperature is measured again. In step 42, the duty cycle is again selected using the predetermined rules, this time based on the battery temperature and the heater resistance. The process is repeated until the target resistance is reached or until 30 seconds after startup, whichever is earlier.

[0114] See Figure 4 The benefit of the described method is that it allows maximum power to be extracted from the battery to rapidly heat the heater, while maintaining the battery voltage above a predefined threshold within sufficient safety margins. The duty cycle starts at a low value and gradually increases at an allowed rate as the heater resistance rises and the battery temperature increases. This means that the heater is heated quickly but reliably to its target temperature.

[0115] Figure 5 This describes an additional control process that can be used to further ensure that the MCU always receives sufficient voltage during device operation.

[0116] for Figure 5 The process sets a maximum limit on the rate at which the output battery voltage is generated; this is referred to here as the limit on the rate of voltage drop. The limit on the rate of voltage drop may vary for different subrules or for different battery voltages being measured.

[0117] If the rate of voltage drop exceeds a certain limit, the duty cycle of the current will decrease in order to slow down the rate of voltage drop.

[0118] Figure 5The process shown begins at step 50, where the battery voltage is measured. In step 51, the battery voltage drop rate is calculated based on the measured battery voltage and measurements of the battery voltage taken in previous process loops. In step 52, the MCU determines whether the battery voltage drop rate is greater than a threshold (or whether the battery voltage change rate is less than a threshold). If the battery voltage drop rate is greater than the threshold, the duty cycle is reduced by a predetermined amount in step 53. The process then returns to step 50. For example, if the current duty cycle is 20%, a maximum battery voltage drop rate of 0.5V / s can be defined. For example, the battery voltage drop rate is measured every 200ms interval. If the battery voltage drop rate is greater than the threshold in step 52, the duty cycle is reduced from 20% to 15%, and if the battery voltage drop rate is still greater than 0.5V / s in the next loop after another 200ms, the battery voltage drop rate is further reduced from 15% to 10%. The lower limit of the duty cycle can be set to 5%. If the process requires a reduction in the duty cycle from 5%, then the device can be deactivated.

[0119] This process is advantageous because it prevents the voltage at the MCU from dropping below the minimum operating voltage due to the rapid voltage drop following the change in duty cycle. For example, if the output battery voltage starts at 3.4V and decreases at a rate of 0.5V / s, it will reach 2.4V in less than 2 seconds. This voltage is below the minimum operating voltage of 2.5V and will be reached in just 2 seconds, which is insufficient for the heater to heat up significantly.

[0120] If the rate of battery voltage drop increases, then Figure 5 The process also allows the duty cycle to increase after a decrease. However, before the duty cycle increases, the process requires the rate of voltage drop to be below a threshold for two cycles. For this purpose, after an initial duty cycle decrease where the battery voltage drop rate is below the threshold, the count is incremented for each cycle. If the rate of voltage drop is below the threshold, the count is incremented one-by-one in step 54. If the rate of voltage drop is above the threshold, the count is reset to zero in step 53. The duty cycle is only increased in step 56 if the count is determined to be two in step 55. Otherwise, the duty cycle remains unchanged. In the described example, this means that the rate of battery voltage drop must be less than 0.5V / s within 400ms of recovering a 5% gradual increase (rather than within 200ms of a 5% gradual decrease). This hysteresis provides stability to the system.

[0121] Other variables that may affect the ideal duty cycle used include the battery's age (which can be measured as a count of the number of charge and discharge cycles performed by the battery), the battery's internal resistance, or the battery's internal impedance. One or more of these variables can be used as a first or second characteristic. Alternatively, to provide finer control over the duty cycle, it is possible to use another layer or multiple layers of rules within the hierarchy of rules and sub-rules based on one or more of these variables. For example, a third characteristic could be the count of the number of charge and discharge cycles the battery has performed. The count of the number of charge and discharge cycles the battery has performed can be recorded and stored in the memory within the control unit. Modification based on heater resistance Figure 3 In this embodiment—instead of specifying a duty cycle for each measured heater resistance, multiple sub-rules can be specified for each value of the heater resistance. Each sub-rule can specify the duty cycle to be used for a range of values ​​of the count of charge and discharge cycles that the battery has completed. The sub-rule to be used is selected based on the stored counts of charge and discharge cycles in the control unit's memory. In this way, the duty cycle is selected based on the battery temperature, the heater resistance, and the number of charge and discharge cycles completed by the battery. The order in which the measured characteristics are assigned to the rules, sub-rules, and sub-sub-rules can vary.

Claims

1. A method for controlling the power supplied to an aerosol generating element of an aerosol generating apparatus, the aerosol generating apparatus including a control unit and a battery for delivering power to the aerosol generating element and the control unit, wherein, The method includes the following steps: The battery is measured using a measuring unit, wherein at least one first characteristic of the battery is either its temperature or its internal resistance; and If the measured temperature of the battery is lower than the minimum temperature or the measured internal resistance is greater than the maximum internal resistance, cancel the start-up or shutdown of the device. The control unit is configured to adjust the duty cycle of the current supplied from the battery to the aerosol generating element. The method further includes using the control unit to adjust the duty cycle of the current supplied from the battery to the aerosol generating element based on a predetermined rule, wherein the predetermined rule includes outputting a value of the duty cycle based on at least one measured first characteristic.

2. The method according to claim 1, wherein, The minimum temperature is -10 °C.

3. The method according to claim 1 or 2, wherein, The duty cycle of the current supplied from the battery to the aerosol generating element is adjusted to maintain the voltage at the control unit at or above the minimum operating voltage.

4. The method according to claim 1 or 2, further comprising: The battery output voltage is periodically measured, and the rate of decrease of the output voltage is calculated based on the measured output voltage. The duty cycle is reduced when the rate of decrease of the output voltage exceeds a threshold level.

5. The method according to claim 1 or 2, further comprising the following step: A measuring unit is used to measure a second characteristic of the aerosol generating device, which is at least one of the following: a measure of battery age; resistance or temperature of the aerosol generating element; or the rate of decrease of the output battery voltage.

6. The method according to claim 5, wherein, The control unit is configured to adjust the duty cycle of the current supplied from the battery to the aerosol generating element, wherein the method further includes: using the control unit to adjust the current supplied from the battery to the aerosol generating element based on a predetermined rule, and wherein the predetermined rule includes outputting a value of the duty cycle based on a measured second characteristic.

7. The method according to claim 1 or 2, wherein, The measuring unit includes a temperature sensor for measuring the temperature of the battery.

8. The method according to claim 7, wherein, The temperature sensor is a thermistor.

9. The method according to claim 1 or 2, wherein, The first characteristic is the battery's internal resistance, and the steps for measuring the internal resistance include passing alternating current into the battery and measuring the associated voltage of the alternating current.

10. The method according to claim 1 or 2, wherein, The measurement and adjustment steps are performed periodically.

11. The method according to claim 10, wherein, The measurement and adjustment steps are performed every 0.5 seconds.

12. The method according to claim 1 or 2, wherein, The aerosol generating device includes an aerosol generating element.

13. A control unit for an aerosol generating apparatus, the aerosol generating apparatus comprising: Batteries used to deliver current to aerosol generating elements and control units; And a measuring unit for measuring at least one first characteristic of the battery, the first characteristic being the battery's temperature or internal resistance; wherein the control unit is configured to: retract the activation or deactivation of the device if the measured temperature of the battery is lower than a minimum temperature or the measured internal resistance of the battery is greater than a maximum internal resistance. The control unit is configured to adjust the duty cycle of the current supplied from the battery to the aerosol generating element based on a predetermined rule, wherein the predetermined rule outputs the value of the duty cycle based on at least one measured first characteristic.

14. The control unit according to claim 13, wherein, The minimum temperature is -10 °C.

15. The control unit according to claim 13 or 14, wherein, The control unit is configured to adjust the duty cycle of the current from the battery supply to the aerosol generating element so as to maintain the voltage at the control unit at or above the minimum operating voltage.

16. The control unit according to claim 13 or 14, wherein, The measuring unit is used to measure a second characteristic of the aerosol generating device, which is at least one of the following: a measure of battery age; resistance or temperature of the aerosol generating element; or the rate of decrease of the output battery voltage.

17. The control unit according to claim 16, wherein, The control unit is configured to adjust the duty cycle of the current supplied from the battery to the aerosol generating element, and to adjust the current supplied from the battery to the aerosol generating element based on a predetermined rule, wherein the predetermined rule includes outputting a value of the duty cycle based on a measured second characteristic.

18. The control unit according to claim 13 or 14, wherein, The measuring unit includes a temperature sensor for measuring the temperature of the battery.

19. The control unit according to claim 18, wherein, The temperature sensor is a thermistor.

20. The control unit according to claim 13 or 14, wherein, The first characteristic is the internal resistance of the battery, and the measuring unit is configured to measure the internal resistance by passing alternating current into the battery and measuring the associated voltage of the alternating current.

21. The control unit according to claim 13 or 14, wherein, The aerosol generating device includes an aerosol generating element.

22. An aerosol generating apparatus, comprising: The control unit according to any one of claims 13 to 21; Batteries used to deliver current to aerosol generating elements and control units; And a measuring unit for measuring at least one first characteristic of the battery, the first characteristic being the battery's temperature or internal resistance.

23. The aerosol generating apparatus according to claim 22, comprising: Aerosol generating element.

24. The aerosol generating apparatus according to claim 23, wherein, The aerosol generating element is a resistance heater.

25. The aerosol generating apparatus according to any one of claims 22 to 24, wherein, The battery is a lithium-ion battery.

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