An aerosol generating system and a method of controlling an aerosol generating system

Abstract

An aerosol generating system is described. The aerosol generating system may include an aerosol generating device (10) with a lithium-ion battery (22) comprising a lithium metal anode and a solid electrolyte, an electrical load (e.g., a heater (36)), and a controller (24). The battery (22) has a nominal output voltage. The controller (24) operates the aerosol generating device (10) if the output voltage of the battery (22) is within a standard operating voltage range defined by minimum and maximum standard operating voltages, and will carry out over-discharge protection if the output voltage of the battery (22) is equal to or falls below an over-discharge threshold voltage. The controller (24) will selectively carry out a process by: discharging the battery (22) to supply power to the electrical load (36) at a first discharging rate or a first power for a period of time, and then discharging the battery (22) to supply power to the electrical load (36) at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage is less than or equal to a process threshold voltage, the process threshold voltage being greater than the over-discharge threshold voltage and less than the minimum standard operating voltage; waiting for a fixed or variable period of time with the output voltage of the battery (22) being less than or equal to the process threshold voltage; and charging the battery (22) from an external power source until the output voltage of the battery (22) is greater than the process threshold voltage, and optionally until the output voltage of the battery (22) reaches a higher voltage.

Description

[0001] AN AEROSOL GENERATING SYSTEM AND A METHOD OF CONTROLLING AN AEROSOL GENERATING SYSTEM

[0002] Technical Field

[0003] The present disclosure relates generally to an aerosol generating system, and in particular to an aerosol generating system that includes an aerosol generating device that is configured to heat aerosol generating material to generate an aerosol for inhalation by a user. The aerosol generating device may be adapted to generate an aerosol during an operating session (e.g., a vaping session) in which the aerosol generating material is heated by a heater or heater assembly. The present disclosure is particularly applicable to a portable (hand-held) aerosol generating device.

[0004] The aerosol generating material may be part of an aerosol generating article that may be received in the device in use.

[0005] The aerosol generating system may also include a portable (hand-held) charger (e.g., a “pocket charger”). The aerosol generating device may be received in, or engaged with, the charger to charge a battery of the aerosol generating device.

[0006] The present disclosure also relates to a method for controlling an aerosol generating system.

[0007] Technical Background

[0008] Devices which heat, rather than bum, 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, and in some cases as high as 350°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.

[0009] The aerosol generating material may be a solid. For example, the aerosol generating article may include a solid or semi-solid substrate of plant derived material, such as tobacco. The aerosol generating device may include a heater and an energy storage device such as a battery. The battery may be a rechargeable battery that may be charged from an external power source by a charging assembly of the aerosol generating device. A common type of rechargeable battery for use in aerosol generating devices is a lithium-ion battery. During an operating session of the aerosol generating device (e.g., a vaping session) the battery may supply power to the heater for heating the aerosol generating material to generate an aerosol.

[0010] The size of the battery is a known limiting factor in determining the size and weight of an aerosol generating device. Accordingly, there is a desire to make the battery as small as possible. Lithium-ion batteries with a

[0011] P51838WO-6817lithium metal anode and solid electrolyte (e.g., “solid-state batteries”) are known to have a high energy density, which means that the size of the battery may be reduced while still meeting energy storage requirements. In other words, reducing the size of the battery should ideally not result in the need for the user to recharge the battery more often, or where a fully-charged battery is only able to provide enough power for the user to complete a fewer number of vaping sessions before it needs to be recharged. It may be understood that the high energy density of solid-state lithium-ion batteries is a result of the lack of any separator between the anode and the cathode.

[0012] Although solid-state lithium-ion batteries have a higher energy density than some other types of rechargeable battery, a known disadvantage with this type of battery is a lower cycle life. One of the factors that may affect cycle life is that lithium metal material may be dissolved from the anode and become trapped in the solid electrolyte interface (SEI), which is a passivation layer or matrix formed at the interface between the lithium metal anode and the solid electrolyte. The SEI may comprise decomposed electrolyte that surrounds the dissolved lithium metal material. In this case, the dissolved lithium metal material becomes inactive and cannot participate any longer in the electro-chemical reaction. This limits the discharging and charging capabilities of the battery, thereby reducing cycle life.

[0013] The present disclosure describes a process for controlling the discharging and charging of a solid-state lithium-ion battery that aims to reduce known aging effects and improve cycle life.

[0014] Summary of the Disclosure

[0015] According to a first aspect of the present disclosure, there is provided an aerosol generating system comprising:

[0016] a lithium-ion battery comprising a lithium metal anode and a solid electrolyte, the battery having a nominal output voltage;

[0017] an electrical load (e.g., a heater or other component that is electrically connected to the battery and to which the battery may supply power); and

[0018] a controller adapted to operate the aerosol generating system if the output voltage of the battery is within a standard operating voltage range defined by minimum and maximum standard operating voltages, and to carry out over-discharge protection if the output voltage of the battery is equal to or falls below an over-discharge threshold voltage;

[0019] wherein the controller is further adapted to selectively carry out a process by:

[0020] discharging the battery to supply power to the electrical load at a first discharging rate or a first power for a period of time, and then discharging the battery to supply power to the electrical load at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage of the battery is less than or equal to a process threshold voltage, wherein the process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage,

[0021] P51838WO-6817waiting for a period of time with the output voltage of the battery being less than or equal to the process threshold voltage, and

[0022] charging the battery from an external power source until the output voltage of the battery is greater than the process threshold voltage.

[0023] As described in more detail below, the aerosol generating system may comprise an aerosol generating device which comprises the battery, the electrical load, and the controller. The aerosol generating system may also comprise a hand-held charger (e.g., a “pocket charger”) for charging the aerosol generating device when the aerosol generating device is engaged with the hand-held charger. In this case, the battery may be part of the hand-held charger and the controller may be part of the aerosol generating device or the handheld charger. The aerosol generating device and the hand-held charger may each have a battery and a controller. If the battery is part of an aerosol generating device, the aerosol generating device may be operated normally (e.g., to generate an aerosol during a vaping session) if the output voltage of the battery is within the standard operating voltage range. Over-discharge protection may be carried out by the controller of the aerosol generating device if necessary. If the battery is part of a hand-held charger, the hand-held charger may be operated normally (e.g., to charge the battery of the aerosol generating device) if the output voltage of the battery of the hand-held charger is within the standard operating voltage range. Over-discharge protection may be carried out by the controller (e.g., a controller of the aerosol generating device and / or a controller hand-held charger) if necessary.

[0024] The term “nominal output voltage” used herein is the average output voltage of the battery when discharging. The nominal output voltage of the battery will normally be specified in the data sheet provided by the manufacturer, and in some cases may be about 3.7V, for example. In practice, the nominal output voltage may also be marked on a surface of the battery.

[0025] During normal operation of the aerosol generating system (e.g., when an aerosol generating device or a hand-held charger is being operated normally), the actual output voltage of the battery may be higher or lower than the nominal output voltage. The controller is adapted so that the aerosol generating system is only operated if the output voltage is within the standard operating range as defined by the minimum and maximum standard operating voltages. For example, if the nominal output voltage is about 3.7 V, the minimum standard operating voltage may be between about 2.8 V and about 3.2 V (e.g., about 3.0 V) and the maximum standard operating voltage may be between about 4.0 V and about 4.4 V (e.g., about 4.2 V), for example. The maximum standard operating voltage may correspond to the fully charged voltage of the battery, for example. The minimum standard operating voltage may correspond to the discharge cut-off voltage of the battery, for example.

[0026] For safety, the controller is adapted to provide over-discharge protection if the output voltage of the battery is equal to or falls below an over-discharge threshold voltage. The over-discharge threshold voltage is lower than the minimum standard operating voltage. For example, if the minimum standard operating voltage is between about 2.8 V and about 3.2 V, the over-discharge threshold voltage may be between

[0027] P51838WO-6817about 2.0 V about 2.5 V, for example. If the output voltage of the battery falls below the over-discharge threshold voltage, the controller may suspend operation of the aerosol generating system, e.g., prevent operation of an aerosol generating device or hand-held charger that forms part of the aerosol generating system.

[0028] The process carried out by the controller may be a capacity recovery process that aims to at least partially recover the charge capacity of the battery. In particular, discharging the battery and waiting for a period of time with the output voltage of the battery being less than or equal to the process threshold voltage (i.e., resting the battery in a discharged state) can allow some of the decomposed electrolyte in the solid electrolyte interface (SEI) to dissolve away. When the battery is subsequently charged, some of the lithium metal material that was previously trapped, and which had become inactive, will reconnect with the lithium metal anode. The lithium metal material may therefore participate in the electro-chemical reaction. Selectively carrying out such a charge capacity recovery process may therefore at least partially recover the charge capacity of the battery and reduce the aging effects that shorten cycle life.

[0029] The controller may selectively carry out the process based on an input from the user of the aerosol generating system (i.e., where the user tells the controller to carry out the process), or the controller may carry out the process automatically based on operating parameters of the aerosol generating system, e.g., when battery health or charge capacity falls below a threshold. The process may be carried out instead of normal battery charging. In other words, instead of just charging the battery when the charge capacity is low, the process may be carried out by the controller so that the battery is discharged and then rested in the discharged state, before being charged to a predefined voltage. The process may be scheduled by the controller based on user behaviour - i.e., so that the process may be carried out when the user does not typically want to use the aerosol generating system (e.g., at night or when the user is asleep). The process may take several hours to complete, but carrying out the process when the user typically does not want to use the aerosol generating system will minimise user inconvenience. For example, the user may not feel inconvenienced if the process is scheduled and carried out when they are asleep. The controller may suggest that the process is started, or may schedule the process to be started (e.g., based on user behaviour), and then require user confirmation before carrying out the process. This allows the user to prevent the process from being carried out if the user wants to use the aerosol generating system, or if carrying out the process at the scheduled time would not be possible because the user will not have access to an external power source for charging the battery, for example.

[0030] During the process, the battery is discharged until the output voltage is less than or equal to a process threshold voltage. The process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage. For example, the process threshold voltage may be in the range of about 2.25 V to about 2.75 V. This provides a full discharge of the battery without triggering any over-discharge protection. Although the battery may be discharged so that the output voltage is less than the process threshold voltage (e.g., in some cases less than about 2.25 V), the output voltage preferably remains greater than the over-discharge threshold voltage so that over-discharge protection is avoided. In

[0031] P51838WO-6817other words, the battery may be discharged by the controller until the output voltage of the battery is less than the process threshold voltage and greater than the over-discharge threshold voltage. For example, if the over-discharge threshold voltage is about 2.0 V and the process threshold voltage is about 2.25 V, the battery may be discharged until the output voltage is less than about 2.25 V but greater than about 2.0 V. If the over-discharge threshold voltage is about 2.5 V and the process threshold voltage is about 2.75 V, the battery may be discharged until the output voltage is less than about 2.75 V but greater than about 2.5 V. Alternatively, the battery may be discharged until the output voltage of the battery is substantially equal to the process threshold voltage, which is always greater than the over-discharge threshold voltage.

[0032] The time taken to discharge the battery may be between about 60 minutes and about 180 minutes, for example. This will depend on the first and second discharging rates, or the first and second powers, used during the discharging step.

[0033] During the discharging step, the output voltage may be measured (e.g., by a voltage sensor) and the voltage measurements may be inputted to the controller.

[0034] After the battery has been discharged, the battery remains in the discharged state for a period of time. The period of time may be a balance between providing useful charge capacity recovery by allowing time for the repair of the SEI, and the practical need for the overall process time to not inconvenience the user. In other words, the user may not want the aerosol generating system to be unavailable for use for a long period of time while a capacity recovery process is carried out. This may be particularly the case if the benefit of carrying out the capacity recovery process is not immediately clear to the user. The period of time for which the battery should remain in the discharged state may be determined by the controller based on the discharge time (i.e., the time taken to discharge the battery so that the output voltage is less than or equal to the process threshold voltage) and an estimated time to charge the battery. The period of time for which the battery remains in the discharged state may be between about 60 minutes and about 180 minutes, for example.

[0035] The battery may be charged from the external power source until the output voltage of the battery reaches a predefined voltage that is greater than the process threshold voltage. The predefined voltage may be the minimum standard operating voltage or the nominal output voltage, for example. The predefined voltage may be less than or equal to the maximum standard operating voltage, for example. The time taken to charge the battery may be between about 45 minutes and about 90 minutes, for example, depending on charging parameters such as the charging rate and the voltage to which the battery is to be charged - i.e., if the battery is to be charged to the nominal output voltage or the maximum standard operating voltage, the charging will take longer than if the battery is to be charged to the lower minimum standard operating voltage. If necessary, after the process has been completed, the battery may be further charged to a higher output voltage. This further charging may be carried out using a conventional charging process, for example.

[0036] P51838WO-6817The overall time for the process (i.e., including discharging, resting, and charging the battery) to be completed may be between about 165 and about 450 minutes, for example. It will be understood that the process may take a longer or shorter time to complete if the times for discharging, resting, and charging are outside of the example time ranges set out above.

[0037] The period of time between discharging the battery and charging the battery (i.e., the time when the battery remains in the discharged state) may be fixed by the controller, or may be varied based on previous usage of the aerosol generating system and / or an estimated time to charge the battery until the output voltage is greater than the process threshold voltage, e.g., until the output voltage reaches a predefined voltage such as the minimum standard operating voltage or the nominal output voltage, or a voltage that is less than or equal to the maximum standard operating voltage. For example, if the previous usage suggests that the user may want to use the aerosol generating system at a particular time the following morning, the controller may adjust the period of time when the battery remains in the discharged state so that the whole process is complete before that particular time. The period of time when the battery remains in the discharged state may be shortened to reduce the overall time to complete the process so that the aerosol generating system is available for use before the particular time. Alternatively, if more time is available before the user may want to use the aerosol generating system, the period of time when the battery remains in the discharged state may be lengthened to try and maximise charge capacity recovery. The controller may also increase the charging rate at which the battery is charged in order to reduce the overall time to complete the process so that the aerosol generating device is available for use before the particular time, or to allow the battery to remain in the discharged state for a longer period of time without increasing the overall time to complete the process - i.e., the controller may lengthen the rest time and shorten the subsequent charging time. This may avoid inconveniencing the user and may minimise any concern that the aerosol generating system may not be available when the user wants to use it.

[0038] The battery is charged from an external power supply. For example, if the battery is part of an aerosol generating device or a hand-held charger, the aerosol generating device or hand-held charger may comprise a wired charging assembly (e.g., aUSB-C charging assembly) or a wireless charging assembly that includes a power receiving coil for wireless charging.

[0039] The controller is adapted to discharge the battery to the electrical load at a first discharging rate or first power for a period of time, and then discharge the battery to the electrical load at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage of the battery is less than or equal to the process threshold voltage. For example, the first discharging rate may be between about 1 C and about 2 C and the second discharging rate may be between about 0.1 C and about 1 C, or the first power may be between about 0.5 W and about 2.0 W and the second power may be between about 0.1 W and about 1.0. In a first discharging step the first power may be about 1 W, and in a second discharging step that ensures a full discharge of the battery, the second power may be about 0.5 W, for example.

[0040] P51838WO-6817The first discharging step may last between about 30 minutes and about 90 minutes, for example. The second discharging step may last between about 30 minutes and about 90 minutes, for example.

[0041] The controller may be adapted to transition from the first discharging step to the second discharging step, i.e., start discharging the battery to the electrical load at the second discharging rate or second power, when a temperature of the aerosol generating system exceeds a temperature threshold. For example, if the electrical load is a heater, the controller may transition from the first discharging step to the second discharging step when a temperature of the heater exceeds a temperature threshold (e.g., about 40°C). Alternatively, the temperature may be a measured internal or surface temperature of an aerosol generating device or aerosol generating article forming part of the aerosol generating system, for example. Transitioning to a lower discharging rate or a lower power when a temperature exceeds a temperature threshold may avoid the temperature of the aerosol generating system becoming too high during the process. It may also avoid any external heating caused by the aerosol generating system. The transition from the first discharging step to the second discharging step may also be carried out after a predetermined period of time - i.e., when a period of time from the start of the process has elapsed.

[0042] The controller may be adapted to control discharging of the battery to the electrical load using a closed-loop controller based on the error between a target temperature and a temperature of the aerosol generating system. For example, if the electrical load is a heater, the temperature of the aerosol generating system may be a temperature of the heater. If the target temperature is set low enough that any decomposition on the surface of the heater is not volatilised, no odor or smell will be generated by the aerosol generating system when the process is being carried out. Alternatively, the temperature may be a measured internal or surface temperature of an aerosol generating device or aerosol generating article forming part of the aerosol generating system, for example. The target temperature may be fixed or varied during the discharging step, e.g., by using a target temperature profile. If a closed-loop controller is used to control the battery discharging, the first and second discharging rates (or the first and second powers) may not be constant. In this case, the first and second discharging rates may be defined by a maximum or average value. For example, the maximum value of the second discharging rate may be less than the maximum value of the first discharging rate, or the average value of the second discharging rate may be less than the average value of the first discharging rate. Similarly, for example, the maximum value of the second power may be less than the maximum value of the first power, or the average value of the second power may be less than the average value of the first power.

[0043] The controller may be adapted to estimate or determine the degradation (e.g., state of health (SoH)) of the battery. The process may be carried out by the controller only if the degradation is below a degradation threshold. This may ensure that the process is only carried out if there is a need to recover the charge capacity of the battery. This may minimise any inconvenience for the user because normal battery charging may be carried out when the degradation is above the degradation threshold, e.g., when the number of cycles is still relatively low. As used herein, the term “SoH” describes the difference between the current battery and the same battery when new, and may be defined as the ratio of the fully charged capacity of the

[0044] P51838WO-6817aged battery divided by the rated capacity of the battery provided by the manufacturer (i.e., the fully charged capacity of the battery when new). Alternatively, the term “SoH” may be defined as the ratio of the internal resistance value of the battery when new divided by the internal resistance value of the aged battery.

[0045] The process may be carried out by the controller only if the number of cycles is greater than a threshold. This may minimise any inconvenience for the user because normal battery charging may be carried out when the number of cycles is still relatively low.

[0046] The controller may also be adapted to estimate or determine the remaining capacity of the battery (e.g., state of charge (SoC)). The process may be carried out by the controller only if the remaining capacity is below a capacity threshold. This may ensure that the process is only carried out if the expected period of time for discharging the battery is sufficiently short. This may minimise any inconvenience for the user because normal battery charging may be carried out if the expected period of time to discharge the battery means that the overall time to complete the charge capacity recovery process is too long. As used herein, the term “SoC” describes the difference between a fully charged battery and the same battery in use, and may be defined as the ratio of the remaining capacity in the battery divided by the fully charged capacity of the battery. For a new battery, the fully charged capacity is normally equal to the rated capacity of the battery provided by the manufacturer. As the battery ages, the fully charged capacity will decrease and will be less than the rated capacity provided by the manufacturer. If the battery is fully charged the SoC is 100%. If the battery is fully discharged the SoC is 0%. The remaining charge of the battery may be determined or estimated in any suitable way, e.g., using coulomb counting, which relies on the integration of the current drawn from and supplied to the battery over time, or by using other measurements of other electrical parameters of the battery, for example.

[0047] The output voltage of the battery when the SoC is 100% may correspond to the maximum standard operating voltage and / or the fully charged voltage. The output voltage of the battery when the SoC is 0% by correspond to the minimum standard operating voltage and / or the discharge cut-off voltage.

[0048] The aerosol generating system may further comprise a wired charging assembly adapted to charge the battery. For example, the wired charging assembly may be part of an aerosol generating device or handheld charger that forms part of the aerosol generating system. The controller may be adapted to carry out the process only if the external power source is electrically connected to the wired charging assembly. It may generally be the case that wired charging is more reliable than wireless charging because the latter typically requires alignment between the power transmitting and receiving coils to be maintained during the charging process. Only allowing the process to be carried out if an external power source is electrically connected to the wired charging assembly (e.g., by a charging cable) minimises the risk of the process being interrupted before the battery is properly charged. Such interruption may be caused by a disconnection to the external power source. This is important because the user may expect the battery to be charged when the process has been completed so that the aerosol generating system is available for use.

[0049] P51838WO-6817In other words, the user should not be inconvenienced by the controller carrying out the process for recovery of charge capacity, which involves a full discharge of the battery, and there should be as much certainty as possible that the process will not be interrupted leaving the battery in a fully or partially discharged state where the aerosol generating device or hand-held charger cannot be operated without further charging of the battery.

[0050] In some cases, the aerosol generating system may further comprise a wireless charging assembly adapted to charge the battery. This may be in addition to a wired charging assembly. For example, the wireless charging assembly may be part of an aerosol generating device or hand-held charger that forms part of the aerosol generating system. The wireless charging assembly may comprise a power receiving coil adapted for wireless charging of the battery.

[0051] The wireless charging assembly may comprise a magnetic connection and alignment feature. In other words, a feature that is designed to maintain alignment between the power transmitting and receiving coils during the wireless charging process. For example, the wireless charging assembly of the aerosol generating device or hand-held charger may comprise one or more magnets that are designed to hold the aerosol generating device or hand-held charger in position adjacent the surface of an external wireless charger. The external wireless charger may also comprise one or more corresponding magnets or one or more corresponding metal parts that are aligned with the one or more magnets of the aerosol generating device or hand-held charger. Alternatively, if the external wireless charger comprises one or more magnets, the aerosol generating device or hand-held charger may comprise one or more metal parts that are aligned with the one or more magnets and designed to hold the aerosol generating device or hand-held charger in position adjacent the surface of the external wireless charger. The controller may be adapted to carry out the process only if the external wireless charger as the external power source is magnetically connected to the wireless charging assembly. Only allowing the process to be carried out if the external wireless charger is magnetically connected to the wireless charging assembly minimises the risk of the process being interrupted before the battery is properly charged. The magnetic connection may be confirmed based on a suitable sensor (e.g., a Hall sensor or integrated circuit) or any suitable parameter such as charging speed, a magnitude of the charging current etc. or which is related to charging efficiency, and may therefore be affected by the alignment between the power transmitting and receiving coils. Measurements from the sensor or parameter measurements may be inputted to the controller. The controller may therefore determine if a magnetic connection between the aerosol generating device or hand-held charger and the external wireless charger has been made before starting the process.

[0052] Preferably once the process has been started by the controller, the process should not be terminated before it is complete and the battery has been properly charged, e.g., where the output voltage has reached a predefined voltage such as the minimum standard operating voltage, the nominal output voltage, or a voltage that is less than or equal to the maximum standard operating voltage. The controller may be adapted to only allow the process to be terminated if the output voltage of the battery is greater than the process threshold voltage. This may provide a minimum voltage for the aerosol generating system. If necessary,

[0053] P51838WO-6817the battery may then be charged in the usual way to a higher voltage, e.g., the minimum standard operating voltage or the nominal voltage where normal operation of the aerosol generating system may be started. In other words, the battery may be charged until its output voltage is at a higher voltage that is less than or equal to the maximum standard operating voltage.

[0054] The controller may be a microcontroller unit (MCU), for example. The controller may be part of an aerosol generating device that forms part of the aerosol generating system.

[0055] The aerosol generating system may comprise:

[0056] an aerosol generating device, and

[0057] a hand-held charger adapted to engage with the aerosol generating device.

[0058] The battery may be part of the aerosol generating device. The controller may be adapted to not charge the battery when the process is scheduled to be carried out by the controller even if the aerosol generating device is engaged with the hand-held charger. This may prioritise the process (e.g., for recovery of charge capacity) if it is already scheduled to be carried out and prevents the battery of the aerosol generating device from instead being charged by the hand-held charger.

[0059] The electrical load (e.g., heater) may be part of the aerosol generating device or alternatively part of an aerosol generating article that is adapted to be received in the aerosol generating device in use. In the latter case, the electrical load may be electrically connected with the aerosol generating device, e.g., by one or more electrical contacts, when it is received in the aerosol generating device.

[0060] The battery may be part of the hand-held charger.

[0061] The controller may be part of the aerosol generating device and / or the hand-held charger.

[0062] The aerosol generating device may further comprise a second battery that is adapted to be charged by the battery of the hand-held charger when the aerosol generating device is engaged with the hand-held charger. The controller may be adapted to not charge the second battery when the process is being carried out. This may prevent unwanted charging of the second battery when the process (e.g., for recovery of charge capacity) is being carried out on the battery of the hand-held charger. The battery of the hand-held charger may be charged by an external power source. For example, the hand-held charger may comprise a wired charging assembly (e.g., a USB-C charging assembly) or a wireless charging assembly that includes a power receiving coil for wireless charging.

[0063] A heater of the aerosol generating device may be adapted to heat aerosol generating material provided as part of an aerosol generating article. The aerosol generating article may be adapted to be received in a heating chamber of the aerosol generating device. The heatermay be positioned in or adjacent to the heating

[0064] P51838WO-6817chamber, and may extend substantially around the heating chamber so that it may heat the aerosol generating material when the aerosol generating article is received in the heating chamber.

[0065] Aerosol generating material may form part of an aerosol generating article (or “consumable”) and may be surrounded by a paper wrapper.

[0066] The aerosol generating article may be formed substantially in the shape of a stick, and may broadly resemble a cigarette, having a tubular region with an aerosol generating material or substrate arranged in a suitable manner. The aerosol generating article may also be formed as a flat-format article. The aerosol generating article may include a filter segment, for example comprising cellulose acetate fibres, at a proximal end of the aerosol generating article. The filter segment may constitute a mouthpiece filter and may be in coaxial alignment with the aerosol generating material. One or more vapour collection regions, cooling regions, and other structures may also be included in some designs. For example, the aerosol generating article may include at least one tubular segment upstream of the filter segment. The tubular segment may act as a vapour cooling region. The vapour cooling region may advantageously allow the heated vapour generated by heating the aerosol generating material to cool and condense to form an aerosol with suitable characteristics for inhalation by a user, for example through the filter segment.

[0067] 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.

[0068] 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 aerosol-former content of between approximately 5% and approximately 50% on a dry weight basis. In some embodiments, the aerosol generating material may comprise an aerosol-former content of between approximately 10% and approximately 20% on a dry weight basis, and possibly approximately 15% on a dry weight basis.

[0069] The aerosol generating device may be configured 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.

[0070] 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

[0071] P51838WO-6817temperature, 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.

[0072] The aerosol generating device is typically a hand-held, portable, device.

[0073] According to a second aspect of the present disclosure, there is provided a method of controlling an aerosol generating system comprising:

[0074] a lithium-ion battery comprising a lithium metal anode and a solid electrolyte, the battery having a nominal output voltage; and

[0075] an electrical load (e.g., a heater or other component that is electrically connected to the battery and to which the battery may supply power);

[0076] the method comprising:

[0077] operating the aerosol generating system if the output voltage of the battery is within a standard operating voltage range defined by minimum and maximum standard operating voltages, and carrying out over-discharge protection if the output voltage of the battery is equal to or falls below an over-discharge threshold voltage; and

[0078] selectively carrying out a process comprising:

[0079] discharging the battery to supply power to the electrical load at a first discharging rate or a first power for a period of time, and then discharging the battery to supply power to the electrical load at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage of the battery is less than or equal to the process threshold voltage, wherein the process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage,

[0080] waiting for a period of time with the output voltage of the battery being less than or equal to the process threshold voltage, and

[0081] charging the battery from an external power source until the output voltage of the battery is greater than the process threshold voltage, and preferably until the output voltage of the battery reaches a predefined voltage, e.g., the minimum standard operating voltage, the nominal output voltage, or a voltage that is less than or equal to the maximum standard operating voltage.

[0082] Other features of the aerosol generating system and the process may be as described herein.

[0083] P51838WO-6817Brief Description of the Drawings

[0084] Figure 1 is a diagrammatic cross-sectional view of an aerosol generating system comprising an aerosol generating device and an aerosol generating article ready to be positioned in a heating chamber of the aerosol generating device;

[0085] Figure 2 is a diagrammatic view of an aerosol generating device being charged by a wireless charger as an external power source;

[0086] Figure 3 is a diagrammatic view of an aerosol generating device being charged by an external power source using a wired charging cable;

[0087] Figure 4 is a diagrammatic view of an aerosol generating system comprising an aerosol generating device and a hand-held charger;

[0088] Figure 5 is a graph of a charge capacity recovery process; and

[0089] Figure 6 is a flowchart of a charge capacity recovery process.

[0090] Detailed Description of Embodiments

[0091] Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.

[0092] Referring initially to Figure 1, there is shown diagrammatically an example of an aerosol generating system 1. The aerosol generating system 1 comprises an aerosol generating device 10 and an aerosol generating article 100 for use with the device 10. The aerosol generating device 10 comprises a main body 12 housing various components of the aerosol generating device 10. The main body 12 may have any shape that is sized to fit the components described in the various embodiments set out herein and to be comfortably held by a user unaided, in a single hand.

[0093] A first end 14 of the aerosol generating device 10, shown towards the bottom of Figure 1, is described for convenience as a distal, bottom, base or lower end of the aerosol generating device 10. A second end 16 of the aerosol generating device 10, shown towards the top of Figure 1, is described as a proximal, top or upper end of the aerosol generating device 10. During use, the user typically orients the aerosol generating device 10 with the first end 14 downward and / or in a distal position with respect to the user’s mouth and the second end 16 upward and / or in a proximate position with respect to the user’s mouth.

[0094] The aerosol generating device 10 comprises a heating chamber 18 positioned in the main body 12. The heating chamber 18 defines an interior volume in the form of a cavity 20 having a substantially cylindrical cross-section for receiving an aerosol generating article 100. The heating chamber 18 has a longitudinal axis defining a longitudinal direction and is formed of a heat-resistant plastics material, such as poly ether ether ketone (PEEK). The aerosol generating device 10 further comprises a solid-state lithium-ion battery 22, and a microcontroller unit (MCU) 24 that controls the aerosol generating device 10. The battery 22 has a lithium metal anode and a solid electrolyte. A solid electrolyte interface (SEI) is formed at the interface between the lithium metal anode and the solid electrolyte. As described above, the SEI comprises decomposed electrolyte that surrounds dissolved lithium metal material that is inactive and cannot

[0095] P51838WO-6817participate any longer in the electro-chemical reaction. This limits the discharging and charging capabilities of the battery 22, thereby reducing cycle life. The MCU 24 may be part of a control circuit. The control circuit may include one or more integrated circuits (ICs) in addition to the MCU 24, and other electronic components. The control circuit may comprise a printed circuit board assembly (PCBA) with a rigid and / or flexible printed circuit board (PCB) on which the MCU 24 is mounted. A microprocessor unit (MPU) may be employed instead of, or in addition to, the MCU 24.

[0096] The heating chamber 18 is open towards the second end 16 of the aerosol generating device 10. In other words, the heating chamber 18 has an open first end 26 towards the second end 16 of the aerosol generating device 10. The heating chamber 18 is typically held spaced apart from the inner surface of the main body 12 to minimise heat transfer to the main body 12.

[0097] The aerosol generating device 10 may optionally include a sliding cover 28 movable transversely between a closed position (shown in Figure 1) in which it covers the open first end 26 of the heating chamber 18 to prevent access to the heating chamber 18 and an open position (not shown) in which it exposes the open first end 26 of the heating chamber 18 to provide access to the heating chamber 18. The sliding cover 28 may be biased to the closed position in some embodiments.

[0098] The heating chamber 18, and specifically the cavity 20, is arranged to receive a correspondingly shaped generally cylindrical or rod-shaped aerosol generating article 100. Typically, the aerosol generating article 100 comprises a pre-packaged aerosol generating material or substrate 102. The aerosol generating article 100 is a disposable and replaceable article (also known as a “consumable”) which may, for example, contain tobacco as the aerosol generating material 102. The aerosol generating article 100 has a proximal end 104 (or mouth end) and a distal end 106. The aerosol generating article 100 further comprises a mouthpiece segment 108 positioned downstream of the aerosol generating material 102. The aerosol generating material 102 and the mouthpiece segment 108 are arranged in coaxial alignment inside a wrapper 110 (e.g., a paper wrapper) to hold the components in position to form the rod-shaped aerosol generating article 100.

[0099] The mouthpiece segment 108 may comprise one or more of the following components (not shown in detail) arranged sequentially and in co-axial alignment in a downstream direction, in other words from the distal end 106 towards the proximal (mouth) end 104 of the aerosol generating article 100: a cooling segment, a centre hole segment and a filter segment. The cooling segment typically comprises a hollow paper tube having a thickness which is greater than the thickness of the wrapper 110. The centre hole segment may comprise a cured mixture containing cellulose acetate fibres and a plasticizer, and functions to increase the strength of the mouthpiece segment 108. The filter segment typically comprises cellulose acetate fibres and acts as a mouthpiece filter. As heated vapour flows from the aerosol generating material 102 towards the proximal (mouth) end 104 of the aerosol generating article 100, the vapour cools and condenses as it passes through the cooling segment and the centre hole segment to form an aerosol with suitable characteristics for inhalation by a user through the filter segment.

[0100] P51838WO-6817The heating chamber 18 has a side wall (or chamber wall) 30 extending between a base 32, located at a second end 34 of the heating chamber 18, and the open first end 26. The side wall 30 and the base 32 are connected to each other and may be integrally formed as a single piece. In the illustrated embodiment, the side wall 30 is tubular and, more specifically, cylindrical. The side wall 30 may be formed so that the crosssection of the heating chamber 18 may be a perfect circle, an ellipse or an oval, for example. In other embodiments, the side wall 30 may have other suitable shapes, such as a tube with an elliptical or polygonal cross section. In yet further embodiments, the side wall 30 may be tapered.

[0101] In the illustrated embodiment, the base 32 of the heating chamber 18 is closed, e.g., sealed or air-tight. That is, the heating chamber 18 is cup-shaped. This may ensure that air drawn from the open first end 26 is prevented by the base 32 from flowing out of the second end 34 and is instead guided through the aerosol generating material 102. It may also ensure that a user inserts the aerosol generating article 100 into the heating chamber 18 an intended distance and no further. In other embodiments, the base 32 of the heating chamber 18 may be only partially opened so that a cleaning brush may be inserted from the first end 14 through a narrow pipe (not shown).

[0102] The device 10 includes a heater 36, which is configured to heat the aerosol generating material 102 when the aerosol generating article 100 is received in the heating chamber 18.

[0103] The heater 36 receives power from the battery 22. In the process described below, the battery 22 is discharged by supplying power to the heater 36. But it will be understood that the battery 22 may also be discharged to any other electrical load, e.g., another component to which the battery 22 is electrically connected and in which power may be dissipated safely.

[0104] The aerosol generating device 10 may include a wired charging assembly (e.g., a USB-C charging assembly) 38 and a wireless charging assembly 40. In some embodiments, only one of the charging assemblies will be provided. The wireless charging assembly 40 includes a power receiving coil 42. The power receiving coil 42 is suitable for wireless inductive charging of the battery 22. An external wireless charger 46 shown in Figure 2 includes a power transmitting coil 48 that creates an electromagnetic field when an electric current flows through it. The power transmitting coil 48 and the power receiving coil 42 may also be referred to as a primary coil and a secondary coil, respectively. When the power receiving coil 42 of the wireless charging assembly 40 is in close proximity with the wireless charger 46, the electromagnetic field generates an electric current in the power receiving coil 42 of the wireless charging assembly 40 that may be provided to a charging circuit and used to charge the battery 22. Wireless charging is a convenient way to charge the battery 22 without having to physically and / or mechanically connect a charging cable to the aerosol generating device 10.

[0105] The wireless charging assembly 40 also includes a magnetic connection and alignment feature 44. The magnetic connection and alignment feature 44 is designed to maintain alignment between the power

[0106] P51838WO-6817transmitting and receiving coils 48, 42 during the wireless charging process. The wireless charging assembly 40 of the aerosol generating device 10 may comprise one or more magnets (not shown) that are designed to hold the aerosol generating device 10 in position adjacent a surface of the wireless charger 46. The wireless charger 46 may also comprise one or more corresponding magnets (not shown) or one or more corresponding metal parts (not shown) that are aligned with the one or more magnets of the aerosol generating device 10. Alternatively, if the external wireless charger 46 comprises one or more magnets (not shown), the aerosol generating device 10 may comprise one or more metal parts (not shown) that are aligned with the one or more magnets (not shown) and designed to hold the aerosol generating device 10 in position adjacent the surface of the wireless charger 46. The magnetic connection may be confirmed based on a suitable sensor (not shown) or any suitable parameter such as charging speed, a magnitude of the charging current etc., or which is related to charging efficiency, and may therefore be affected by the alignment between the power transmitting and receiving coils 48, 42. Measurements from the sensor (not shown) or parameter measurements may be inputted to the MCU 24. As described in more detail below, the MCU 24 may therefore determine if a magnetic connection between the aerosol generating device 10 and the external wireless charger 46 has been made before starting the process that aims to recover charge capacity of the battery 22.

[0107] In Figure 2, the magnetic connection and alignment feature 44 is shown schematically as being positioned above the receiving coil 42. But it will be understood that in practice the magnetic connection and alignment features 44 may be suitably positioned within the wireless charging assembly 40, and may be arranged inside an aperture of the receiving coil 42 (e.g., inside the coil turns) or arranged at a periphery of the power receiving coil 42, for example. If the power receiving coil 42 is substantially circular, a plurality of circumferentially-spaced magnets may be arranged around the power receiving coil similar to a known MagSafe charger, for example.

[0108] The wireless charging assembly 40 may be provided as a separate component - i.e., separate from the rest of the aerosol generating device 10. For example, the wireless charging assembly 40 may be an accessory that is supplied separately and which may be used to permit wireless charging of the aerosol generating device 10 if the aerosol generating device 10 does not have an internal power receiving coil. The wireless charging assembly 40 may include an electrical port or connector that may be electrically connected to the aerosol generating device 10 to supply power from the receiving coil 42 to the battery 22.

[0109] Figure 2 shows how the battery 22 may be charged using the wireless charger 46. In this case, the wireless charger 46 is an external power source that is used to charge the battery 22 as part of the process.

[0110] Figure 3 shows how the battery 22 may be charged from an external power source 50 using a charging cable 52. In particular, the wired charging assembly 38 includes a USB-C socket (receptacle) for receiving the end of USB-C charging cable 52 (plug). The external power source 50 is used to charge the battery 22 as part of the process.

[0111] P51838WO-6817Figure 4 shows how the battery 22 may be charged using a hand-held charger 54 (e.g., a “pocket charger”). In particular, the aerosol generating device 10 may be engaged with the hand-held charger 54. The handheld charger 54 includes an energy storage device 56 (e.g., one or more rechargeable batteries) which may be used to charge the battery 22 of the aerosol generating device 10 when the aerosol generating device 10 is engaged with the hand-held charger. In this case, the hand-held charger 54 is an external power source. The battery 56 of the hand-held charger 54 may be charged by an external power source. For example, the hand-held charger 54 may comprise a wired charging assembly (e.g., a USB-C charging assembly) or a wireless charging assembly that includes a power receiving coil for wireless charging. The hand-held charger 54 also includes a controller, e.g., a microcontroller (MCU) 58.

[0112] The battery 22 of the aerosol generating device 10 has a nominal output voltage, e.g., about 3.7 V.

[0113] The MCU 24 is adapted to operate the aerosol generating device 10 if the output voltage of the battery 22 is within a standard operating voltage range defined by minimum and maximum standard operating voltages. The minimum standard operating voltage may be about 3.0 V and the maximum standard operating voltage may be about 4.2 V, for example. But it will be understood that other minimum and maximum standard operating voltages may be used. The maximum standard operating voltage may correspond to the fully charged voltage of the battery 22, for example. The minimum standard operating voltage may correspond to the discharge cut-off voltage of the battery 22, for example. It may also mean that the state of charge (SoC) of the battery 22 at the maximum and minimum standard operating voltages respectively is 100% and 0%.

[0114] The MCU 24 is also adapted to carry out over-discharge protection if the output voltage of the battery 22 is equal to or falls below an over-discharge threshold voltage. The over-discharge threshold voltage may be between about 2.0 V and about 2.5 V, for example. If the output voltage of the battery 22 falls below the over-discharge threshold voltage, the MCU 24 may suspend operation of the aerosol generating device 10. Alternatively, or additionally, a dedicated protection integrated circuit (IC) or other electronic component may be used for carrying out the over-discharge protection. For the purposes described herein, the term “controller” may be taken to include both the MCU 24 and / or a dedicated protection IC or other electronic component.

[0115] The MCU 24 is also adapted to carry out a process that aims to recover the charge capacity of the battery 22.

[0116] The charge capacity recovery process includes the steps of:

[0117] - Step 1 A: discharging the battery 22 to the heater 36 at a first discharging rate for a period of time, - Step IB: discharging the battery 22 to the heater 36 at a second discharging rate, that is less than the first discharging rate, until the output voltage of the battery is less than or equal to a process threshold voltage,

[0118] - Step 2: waiting for a period of time with the output voltage of the battery 22 being less than or equal to the process threshold voltage, and

[0119] P51838WO-6817- Step 3: charging the battery 22 from an external power source until the output voltage of the battery 22 is greater than the process threshold voltage, and preferably until the output voltage reaches a higher predefined voltage such as the minimum standard operating voltage or the nominal output voltage (e.g., at least about 3.0 V or 3.7 V). In some cases, the battery 22 may be charged until the output voltage is less than or equal to the maximum standard operating voltage (e.g., about 4.2 V).

[0120] The process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage. For example, for the over-discharge threshold voltage and minimum standard operating voltages mentioned above, the process threshold voltage may be between about 2.25 V and about 2.75 V. The MCU 24 may select an appropriate process threshold voltage for the process based on the over-discharge threshold voltage and the minimum standard operating voltage.

[0121] If the process threshold voltage is about 2.25 V, the battery 22 may be discharged until the output voltage is less than or equal to about 2.25 V, for example. If the process threshold voltage is about 2.75 V, the battery 22 may be discharged until the output voltage is less than or equal to about 2.75 V, for example. The output voltage of the battery 22 may be directly measured by the MCU 24 (e.g., using a voltage sensing circuit such as a voltage divider circuit). Alternatively, or additionally, a dedicated battery monitoring IC (e.g., a fuel gauge IC) may be used. The dedicated battery monitoring IC may communicate periodically with the MCU 24.

[0122] The first discharging rate may be about IC and the second discharging rate may be about 2C, for example.

[0123] Alternatively, the first discharging step (i.e., Step 1A) may use a first power and the second discharging step (i.e., Step IB) may use a second power, lower than the first power. The first power may be about 1 W and the second power may be about 0.5 W, for example.

[0124] Although the battery 22 may be discharged until the output voltage is less than the process threshold voltage, the output voltage of the discharged battery 22 is preferably greater than the over-discharge threshold voltage so that over-discharge protection is not triggered by the MCU 24 or the protection IC. For example, if the over-discharge threshold voltage is about 2.0 V and the process threshold voltage is about 2.25 V, the battery 22 may be discharged until the output voltage is between about 2.0 V and about 2.25 V. Alternatively, if the over-discharge threshold voltage is about 2.5 V and the process threshold voltage is about 2.75 V, the battery 22 may be discharged until the output voltage is between about 2.5 V and about 2.75 V. It will be understood that these examples are based on the respective lower and upper endpoints of the over-discharge threshold and process threshold voltages and that many other ranges for the output voltage of the discharged battery 22 are possible - e.g., the over-discharge threshold voltage may be about 2.0 V and the process threshold voltage may be about 2.75 V, where the battery 22 may then be discharged so that the output voltage is between about 2.0 V and about 2.75 V. In the lower voltage range, the output voltage of the battery 22 may be quickly decreased as the battery 22 is discharged (i.e.,

[0125] P51838WO-6817as current is supplied from the battery 22 to the heater 36). The second discharging step with a lower discharging rate (or lower discharging power) may therefore be advantageous by providing better control of the output voltage of the battery 22. If the MCU 24 can provide highly accurate control of the output voltage of the battery 22 when it is being discharged, the second discharging step may be omitted and battery 22 may be discharged at the first discharging rate until the output voltage of the battery 22 is less than or equal to the process threshold voltage.

[0126] A graph of battery output voltage versus time of an example of a capacity recovery process is shown in Figure 5.

[0127] The process is started by the MCU 24 at time tO where the output voltage of the battery 22 is about 3.2 V. It will be understood that the starting output voltage of the battery 22 is only an example and that it may be anywhere within the standard operating voltage range (e.g., between about 3.0 V and about 4.2 V) depending on the current charge capacity of the battery 22 when the process is started.

[0128] Alternatively, the process may be started by the MCU 24 even if the starting output voltage of the battery 22 is below the minimum standard operating voltage (e.g., below about 3.0 V). In this alternative embodiment, the first discharging step (and optionally the second discharging step) may be shortened or omitted in accordance with a value of the starting output voltage of the battery 22. Otherwise, the MCU 24 may prohibit the process if the starting output voltage of the battery 22 is below the minimum standard operating voltage. This is because the battery 22 may sometimes be damaged if the starting output voltage is too low. The safety of the battery (e.g., during charging and discharging) should be prioritised over the charge capacity recovery process.

[0129] In the first discharging step (i.e., Step 1 A), the battery 22 is discharged to the heater 36 at a first discharging rate. At time tl, the MCU 24 transitions to the second discharging step (i.e., to Step IB) where the battery 22 continues to be discharged to the heater 36, but at a second discharging rate that is lower than the first discharging rate. The battery 22 is discharged until the output voltage of the battery 22 reaches about 2.25 V at time t2 as shown in Figure 5. The output voltage of the battery 22 is less than a process threshold voltage of about 2.5 V and greater than an over-discharge threshold voltage of about 2.0 V.

[0130] The MCU 24 may be adapted to transition from the first discharging step (i.e., Step 1A) to the second discharging step (i.e., to Step IB) when a temperature of the heater 36 exceeds a temperature threshold (e.g., about 40°C). Alternatively, the temperature may be a measured internal or surface temperature of the aerosol generating device 10, for example. Transitioning to a lower discharging rate (or a lower power) when a temperature exceeds a temperature threshold may avoid the temperature of the aerosol generating device 10 becoming too high during the process. It may also avoid any external heating caused by the aerosol generating device 10. The heater temperature may be measured by a temperature sensor (not shown). The transition from the first discharging step to the second discharging step may also be carried

[0131] P51838WO-6817out after a predetermined period of time - i.e., when a period of time from the start of the process has elapsed.

[0132] The MCU 24 may be adapted to control discharging of the battery 22 to the heater 36 using a closed-loop controller based on the error between a target temperature and a temperature of the aerosol generating device (e.g., the heater temperature). If the target temperature is set low enough that any decomposition on the surface of the heater 36 is not volatilised, no odor or smell will be generated by the aerosol generating device 10 when the process is being carried out. If a closed-loop controller is used to control the battery discharging, the first and second discharging rates (or the first and second powers) may not be constant. In this case, the first and second discharging rates may be defined by a maximum or average value. For example, the maximum value of the second discharging rate may be less than the maximum value of the first discharging rate, or the average value of the second discharging rate may be less than the average value of the first discharging rate. Similarly, for example, the maximum value of the second power may be less than the maximum value of the first power, or the average value of the second power may be less than the average value of the first power.

[0133] During the discharging step, the output voltage of the battery 22 may be measured (e.g., by a voltage sensing circuit or battery monitoring IC (not shown)) and the voltage measurements may be inputted or communicated to the MCU 24.

[0134] Once discharged, the battery 22 remains in the discharged state until time t3 (i.e., Step 2). During this time, the charge capacity of the battery 22 may be at least partially recovered as described above.

[0135] The battery 22 is then charged until the output voltage reaches about 3.7 V (e.g., the nominal output voltage) at time t4 (i.e., Step 3). The battery 22 may be charged at any suitable charging rate. It will be understood that the final output voltage of the battery 22 shown in Figure 5 is only an example and the output voltage of the battery 22 may be greater than the process threshold voltage (e.g., about 2.5 V) and less than or equal to the maximum standard operating voltage (e.g., about 4.2 V).

[0136] The first discharging step (i.e., Step 1A) may last between about 30 minutes and about 90 minutes, for example. The time duration P1A shown in Figure 5 is about 40 minutes. The second discharging step (i.e., Step IB) may last between about 30 minutes and about 90 minutes, for example. The time duration P1B shown in Figure 5 is about 80 minutes.

[0137] The period of time for which the battery 22 remains in the discharged state may be between about 60 minutes and about 180 minutes, for example. The time duration P2 for Step 2 shown in Figure 5 is about 120 minutes.

[0138] P51838WO-6817The time taken to charge the battery 22 to a predetermined voltage may be between about 45 minutes and about 90 minutes, for example. The time duration P3 for Step 3 shown in Figure 5 is about 60 minutes. The time duration P3 will vary depending on the output voltage to which the battery 22 is charged.

[0139] The overall time for the process (i.e., including discharging, resting, and charging to the predetermined voltage) to be completed may be between about 165 and about 450 minutes, for example. The total time duration shown in Figure 5 is about 300 minutes.

[0140] The MCU 24 may selectively carry out the process based on an input from the user of the aerosol generating device 10 (i.e., where the user tells the MCU 24 to carry out the process), or the MCU 24 may carry out the process automatically based on operating parameters of the aerosol generating device 10, e.g., when battery health or fully charged capacity falls below a threshold. The process may be carried out instead of normal battery charging. In other words, instead of just charging the battery 22 when the charge capacity is low, the process may be carried out so that the battery 22 is discharged and then rested in the discharged state, before being charged to a predefined voltage. The process may be scheduled by the MCU 24 based on user behaviour - i.e., so that the process may be carried out when the user does not typically want to use the aerosol generating device 10 (e.g., at night or when the user is asleep). Such user behaviour may be obtained from a portable electronic device (e.g., a mobile phone or watch) that is paired with the aerosol generating device 10. The process may take several hours to complete, but carrying out the process when the user typically does not want to use the aerosol generating device 10 will minimise user inconvenience. For example, the user may not feel inconvenienced if the process is scheduled and carried out when they are asleep. The MCU 24 may suggest that the process is started, or may schedule the process to be started (e.g., based on user behaviour), and then require user confirmation before carrying out the process. This allows the user to prevent the process from being carried out if the user wants to use the aerosol generating device 10, or if carrying out the process at the scheduled time would not be possible because the user will not have access to an external power source for charging the battery 22, for example.

[0141] The period of time between discharging the battery 22 and charging the battery 22 (i.e., the time when the battery 22 remains in the discharged state) may be fixed or may be varied based on previous usage of the aerosol generating device 10 and / or an estimated time to charge the battery 22 until the output voltage reaches the predefined voltage, e.g., until it reaches the nominal output voltage as shown in Figure 5. For example, if the previous usage suggests that the user may want to use the aerosol generating device 10 at a particular time the following morning, the MCU 24 may adjust the period of time when the battery 22 remains in the discharged state so that the whole process is complete before that particular time. The period of time when the battery 22 remains in the discharged state may be shortened to reduce the overall time to complete the process so that the aerosol generating device 10 is available for use before the particular time. Alternatively, if more time is available before the user may want to use the aerosol generating device 10, the period of time when the battery 22 remains in the discharged state may be lengthened to try and maximise charge capacity recovery. The MCU 24 may also increase the charging rate at which the battery 22 is charged in order to reduce the overall time to complete the process so that the aerosol generating

[0142] P51838WO-6817device 10 is available for use before the particular time, or to allow the battery 22 to remain in the discharged state for a longer period of time without increasing the overall time to complete the process -i.e., lengthen the rest time and shorten the charging time. This may avoid inconveniencing the user and may minimise any concern that the aerosol generating device 10 may not be available when the user wants to use it.

[0143] The MCU 24 may be adapted to estimate or determine the degradation (e.g., state of health (SoH)) of the battery 22. The degradation of the battery 22 may be obtained from a dedicated IC (e.g., fuel gauge IC) that may form part of the control circuit. The process may be carried out by the MCU 24 only if the degradation is below a degradation threshold. This may ensure that the process is only carried out if there is a need to recover the charge capacity of the battery 22. This may minimise any inconvenience for the user because normal charging may be carried out when the degradation is above the degradation threshold, e.g., when the number of cycles is still relatively low.

[0144] The MCU 24 may also be adapted to estimate or determine the remaining capacity of the battery 22 (e.g., state of charge (SoC)). The process may be carried out by the MCU 24 only if the remaining capacity is below a capacity threshold. This may ensure that the process is only carried out if the expected period of time for discharging the battery 22 is sufficiently short. This may minimise any inconvenience for the user because normal charging may be carried out if the expected period of time to discharge the battery 22 is too long. The output voltage of the battery 22 when the SoC is 100% may correspond to the maximum operating voltage and / or the fully charged voltage. The output voltage of the battery 22 when the SoC is 0% by correspond to the minimum operating voltage and / or the discharge cut-off voltage.

[0145] The MCU 24 may be adapted to carry out the process only if the external power source 50 is electrically connected to the wired charging assembly 38 (see Figure 3). Only allowing the process to be carried out if an external power source 50 is electrically connected to the wired charging assembly 38 (e.g., by the charging cable 52) minimises the risk of the process being interrupted before the battery 22 is charged to the predefined voltage. Such interruption may be caused by a disconnection to the external power source 50. This is important because the user will expect the battery 22 to be charged so that the aerosol generating device 10 is available for use. In other words, the user should not be inconvenienced by the MCU 24 carrying out the process for recovery of charge capacity, which involves a full discharge of the battery 22, and there should be as much certainty as possible that the process will not be interrupted leaving the battery 22 in a fully or partially discharged state where the aerosol generating device 10 cannot be operated without further charging of the battery 22.

[0146] As mentioned above, the MCU 24 may be adapted to carry out the process only if the external wireless charger 46 is magnetically connected to the wireless charging assembly 40 (see Figure 2). Only allowing the process to be carried out if the wireless charger 46 is magnetically connected to the wireless charging assembly 40 minimises the risk of the process being interrupted before the battery 22 is charged to the predefined voltage.

[0147] P51838WO-6817Preferably once the process has been started by the MCU 24, the process should not be terminated before it is complete and the battery 22 has been charged to the predefined voltage. The MCU 24 may be adapted to only allow the process to be terminated if the output voltage of the battery 22 is greater than the process threshold voltage. This may provide a minimum voltage for the aerosol generating device 10 to operate. The battery 22 may then be charged in the usual way to a higher voltage, e.g., the minimum standard operating voltage or the nominal voltage where normal operation of the aerosol generating device 10 may be started.

[0148] If the battery 22 of the aerosol generating device 10 may be charged by a hand-held charger 54 (see Figure 4), the MCU 24 may be adapted to not charge the battery 22 when the process is scheduled to be carried out by the MCU 24 even if the aerosol generating device 10 is engaged with the hand-held charger 54. This may prioritise the process (e.g., for recovery of charge capacity) if it is already scheduled to be carried out and prevents the battery 22 from being charged by the hand-held charger 54.

[0149] The energy storage device 56 of the hand-held charger 54 shown in Figure 4 may be a solid-state lithium ion with a lithium metal anode and a solid electrolyte. A solid electrolyte interface (SEI) is formed at the interface between the lithium metal anode and the solid electrolyte. As described above, the SEI comprises decomposed electrolyte that surrounds dissolved lithium metal material that is inactive and cannot participate any longer in the electro-chemical reaction. This limits the discharging and charging capabilities of the battery 56, thereby reducing cycle life. The process described above with reference to Figures 5 and 6 may therefore also be carried out on the battery 56 of the hand-held charger 54 for the recovery of charge capacity. The MCU 24 may be adapted to not charge the battery 22 of the aerosol generating device 10 from the battery 56 of the hand-held charger 54 when the charge capacity recovery process is being carried out on the battery 56 of the hand-held charger 54.

[0150] 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 abovedescribed exemplary embodiments.

[0151] 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.

[0152] 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”.

[0153] P51838WO-6817

Claims

-24 - Claims1. An aerosol generating system comprising:a lithium-ion battery (22) comprising a lithium metal anode and a solid electrolyte, the battery (22) having a nominal output voltage;an electrical load (36); anda controller (24) adapted to operate the aerosol generating system if the output voltage of the battery (22) is within a standard operating voltage range defined by minimum and maximum standard operating voltages, and to carry out over-discharge protection if the output voltage of the battery (22) is equal to or falls below an over-discharge threshold voltage;wherein the controller (24) is further adapted to selectively carry out a process by:discharging the battery (22) to supply power to the electrical load (36) at a first discharging rate or a first power for a period of time, and then discharging the battery (22) to supply power to the electrical load (36) at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage is less than or equal to a process threshold voltage, wherein the process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage,waiting for a period of time with the output voltage of the battery (22) being less than or equal to the process threshold voltage, andcharging the battery (22) from an external power source (46; 50; 54) until the output voltage of the battery (22) is greater than the process threshold voltage.

2. An aerosol generating system according to claim 1, wherein the controller (24) is adapted to transition to discharging the battery (22) to the electrical load (36) at the second discharging rate or second power when a temperature of the aerosol generating system exceeds a temperature threshold.

3. An aerosol generating system according to claim 1 or claim 2, wherein the controller (24) is adapted to control discharging of the battery (22) to the electrical load (36) using a closed-loop controller based on the error between a target temperature and a temperature of the aerosol generating system.

4. An aerosol generating system according to any preceding claim, wherein the period of time between discharging the battery (22) and charging the battery (22) is fixed or is varied based on previous usage of the aerosol generating system and / or an estimated time to charge the battery (22) until the output voltage reaches the minimum standard operating voltage or the nominal output voltage.

5. An aerosol generating system according to any preceding claim, wherein the controller (24) is adapted to estimate or determine the degradation of the battery (22), and to carry out the process only if the degradation is below a degradation threshold.P51838WO-68176. An aerosol generating system according to any preceding claim, wherein the controller (24) is adapted to estimate or determine the remaining capacity of the battery (22) and to carry out the process only if the remaining capacity is below a capacity threshold.

7. An aerosol generating system according to any preceding claim, further comprising a wired charging assembly (38) adapted to charge the battery (22), and wherein the controller (24) is adapted to carry out the process only if the external power source (50) is electrically connected to the wired charging assembly (38).

8. An aerosol generating system according to claim 7, further comprising a wireless charging assembly (40) adapted to charge the battery (22).

9. An aerosol generating system according to any of claims 1 to 6, further comprising a wireless charging assembly (40) with a magnetic connection and alignment feature (44), adapted to charge the battery (22), and wherein the controller (24) is adapted to carry out the process only if an external wireless charger (46) as the external power source is magnetically connected to the wireless charging assembly (40).

10. An aerosol generating system according to any preceding claim, wherein the controller (24) is adapted to only allow the process to be terminated if the output voltage of the battery (22) is greater than or equal to the process threshold voltage.

11. An aerosol generating system according to any preceding claim, comprising an aerosol generating device (10), and a hand-held charger (54) adapted to engage with the aerosol generating device (10), wherein the battery (22) is part of the aerosol generating device (10), and the controller (24) is adapted to not charge the battery (22) when the process is scheduled to be carried out by the controller (24) even if the aerosol generating device (10) is engaged with the hand-held charger (54).

12. An aerosol generating system according to any of claims 1 to 10, comprising an aerosol generating device (10), and a hand-held charger (54) adapted to engage with the aerosol generating device, wherein the electrical load (36) is part of the aerosol generating device (10), the battery (56) is part of the hand-held charger (54), and the controller (24) is part of the aerosol generating device (10) and / or the hand-held charger (54).

13. An aerosol generating system according to claim 12, wherein the aerosol generating device (10) further comprises a second battery (22) that is adapted to be charged by the battery (56) of the hand-held charger (54) when the aerosol generating device (10) is engaged with the hand-held charger (54), and wherein the controller (22) is adapted to not charge the second battery (22) when the process is being carried out on the battery (56) of the hand-held charger (54).P51838WO-681714. An aerosol generating system according to any preceding claim, wherein the electrical load is a heater (36).

15. A method of controlling an aerosol generating system comprising:a lithium-ion battery (22) comprising a lithium metal anode and a solid electrolyte, the battery (22) having a nominal output voltage; andan electrical load (36);the method comprising:operating the aerosol generating system if the output voltage of the battery (22) is within a standard operating voltage range defined by minimum and maximum standard operating voltages, and carrying out over-discharge protection if the output voltage of the battery (22) is equal to or falls below an over-discharge threshold voltage; andselectively carrying out a process comprising:discharging the battery (22) to supply power to the electrical load (36) at a first discharging rate or a first power for a period of time, and then discharging the battery (22) to supply power to the electrical load (36) at a second discharging rate, lower than the first discharging rate, or at a second power, lower than the first power, until the output voltage of the battery (22) is less than or equal to a process threshold voltage, wherein the process threshold voltage is greater than the over-discharge threshold voltage and less than the minimum standard operating voltage,waiting for a period of time with the output voltage of the battery (22) being less than or equal to the process threshold voltage, andcharging the battery (22) from an external power source (46; 50; 54) until the output voltage of the battery (22) is greater than the process threshold voltage.P51838WO-6817

Images