Aerosol generation device for current protection

Abstract

There is disclosed aerosol generation device for implementing a current protection scheme, comprising: a circuit, arranged to receive electrical power from a battery; and a processor configured to: determine an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery.

Description

[0001] AL Ref: P47025WO | JTI Ref: 6838 1

[0002] Aerosol Generation Device for Current Protection

[0003] The present disclosure relates to an aerosol generation device configured to implement a current protection scheme and a method of implementing a current protection scheme.

[0004] Background

[0005] Handheld electronic devices, such as aerosol generation devices typically comprise a battery, such as a lithium-ion battery, to deliver electrical power to electronic components of the electronic device. Situations may occur in which one or more electronic components malfunction, or otherwise behave in an undesirable manner. For example, an electronic component may draw too much current than is desired. For example, a situation may occur in which there is a short circuit condition meaning that electrical current takes an unintended path with low or extremely low electrical resistance.

[0006] Such undesired situations may cause malfunction, undesired behaviour of the device and / or damage. As an example, it will be appreciated that aerosol generation devices typically comprise a heat provision arrangement, which may in some examples be in the form of a resistive heater. For example, the resistive heater may draw too much current and consequently generate too much heat within the aerosol generation device.

[0007] It is the object of the invention to overcome at least some of the above referenced problems.

[0008] Summary

[0009] According to the present disclosure there is provided an aerosol generation device for implementing a current protection scheme, comprising: a circuit, arranged to receive electrical power from a battery; and a processor configured to: determine an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery.

[0010] Advantageously, the processor of the aerosol generation device determines the electrical current magnitude without the need for current measuring instrumentation.AL Ref: P47025WO | JTI Ref: 6838 2

[0011] Omitting such instrumentation makes manufacture more cost effective and simpler without any loss of functionality. Furthermore, sensing current using instrumentation may not be fast enough for the kind of real-time monitoring of current which may be desired to implement overcurrent / short circuit protection schemes. For example, an undesired current condition within the circuit may be detected later than desired using instrumentation. On the other hand, determining the electrical current magnitude in the disclosed manner provides for real-time / fast monitoring of the electrical current in the circuit. In addition, the battery characteristic model allows for the determination to take account of the nature and current state of the battery. Also, by using the battery characteristic model, accuracy of the electrical current magnitude is also enhanced, and may be improved over conventional current sensing instrumentation.

[0012] Optionally, the battery characteristic model indicates a variation of internal resistance of the battery.

[0013] Advantageously, the internal resistance value used in any determination is more accurate. Use of a more accurate internal resistance value of the battery provides for more accurate determination of the electrical current magnitude. It is also an advantage that the battery characteristic model indicates such a variation without this variation having to be measured in a live manner during use of the aerosol generation device. In this way, determination of the electrical current magnitude reflects the current state of the battery without putting an extra processing and instrument sensing burden on the device during use.

[0014] Optionally, the battery characteristic model indicates a correspondence between a state of charge of the battery and a respective internal resistance value of the battery.

[0015] Advantageously, an appropriate internal resistance value is available depending on the state of charge. This is advantageous because the state of charge is expected to change as a session of use of the device progresses. The state of charge of the battery affects the internal resistance value. Therefore, the state of charge is taken into account so as to maintain accuracy in the determination of the electrical current magnitude.

[0016] Optionally, the battery characteristic model indicates correspondences between states of charge of the battery, internal resistance values of the battery and open circuit voltage values of the battery.AL Ref: P47025WO | JTI Ref: 6838 3

[0017] Advantageously, there is provided a set of values for internal resistance and open circuit voltage associated with different states of charge. In this way, the battery characteristic model can provide accurate inputs for the current determination model. By including the open circuit voltage dependent on state of charge, the battery characteristic model is further enhanced beyond indication of a correspondence between the internal resistance and state of charge alone. The granularity of the data in the battery characteristic model (in other words, the interval size between state of charge values) can be set according to the desired accuracy of the internal resistance and open circuit voltage values.

[0018] Optionally, the processor is configured to input an internal resistance value of the battery and a voltage drop state of the battery into the current determination model; and obtain the electrical current magnitude as an output from the current determination model.

[0019] Advantageously, the processor is deployed in this manner to use the current determination model to arrive at an electrical current magnitude. The relevant values can be input and the electrical current magnitude determined from the model. Such a determination can, advantageously, be performed at a fast rate to determine the state of the electrical current in the aerosol generation device substantially in real time.

[0020] Optionally, the processor is configured to: determine an open circuit voltage of the battery and a loaded voltage of the battery; and determine the voltage drop state based on the determined open circuit voltage and the loaded voltage.

[0021] Advantageously, the processor can determine the voltage drop state in an accurate manner based on the battery and the relevant voltage conditions in the circuit.

[0022] Optionally, the open circuit voltage is obtained from the battery characteristic model. Advantageously, appropriate values for the open circuit voltage are available and can quickly be deployed from the battery characteristic model.

[0023] Optionally, the aerosol generation device comprises a voltage measurement system configured to measure a voltage value across the battery, wherein, the processor is configured to determine the loaded voltage based on a measurement obtained from theAL Ref: P47025WO | JTI Ref: 6838 4

[0024] voltage measurement system when the battery is connected to deliver electrical power to the circuit.

[0025] Advantageously, there is provided a voltage measurement system so that the voltage drop can be determined for the current determination. For example, the loaded voltage is subtracted from the open circuit voltage to determine the voltage drop. A voltage measurement is faster to obtain and less invasive to the electrical circuit. That is because a current is passed through a series resistance to be measured, which also makes current measurements using instrumentation generally less accurate. Accordingly, determinations on the basis of measurements from the voltage measurement system provide advantages over using current measurement instrumentation.

[0026] Optionally, the aerosol generation device comprises a cutoff mechanism configured to disconnect the battery from the circuit, wherein the processor is configured to: compare the determined electrical current magnitude to at least one current protection threshold; and trigger the cutoff mechanism if the determined electrical current magnitude reaches or exceeds the one or more current protection threshold.

[0027] Advantageously, there is provided a mechanism to disconnect the battery if the determined current reaches an undesired level. This works together with the substantially real-time current monitoring to implement effective current protection. For example, a particular component (such as a heater) can be inhibited from drawing a high current at an undesired level.

[0028] Optionally, the processor is configured iteratively to: i) determine the electrical current magnitude in the circuit; and ii) compare the determined electrical current magnitude to the one or more current protection threshold, until the cutoff mechanism is triggered.

[0029] Advantageously, the processor continuously determined the electrical current magnitude and compares to the relevant threshold. In this way, there is real time monitoring of the current and the cutoff mechanism is triggered as soon as undesired conditions are detected. The iterative processing can also be varied, e.g., deployed during certain parts of a use session of the aerosol generation device and not used in other parts (e.g., when a heater of the device is inactive).AL Ref: P47025WO | JTI Ref: 6838 5

[0030] Optionally, the processor is configured to reinitiate the iterations of processes i) and ii) when the cutoff mechanism is deactivated after being triggered.

[0031] For example, the processor may deactivate the cutoff mechanism, e.g., when the device has been reset and / or repaired and / or after a given length of time. Then, advantageously, the monitor of the current can resume.

[0032] Optionally, the cutoff mechanism comprises a MOSFET. Advantageously, MOSFETs are fast acting electronic switches which can easily be controlled electronically by the processor.

[0033] According to a second aspect of the present disclosure, there is provided a method of implementing a current protection scheme in an aerosol generation device, wherein the aerosol generation device comprises a circuit, and a battery configured to deliver electrical power to the circuit, and a processor, the method comprising: determining, via the processor, an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery.

[0034] Advantageously, implementation of the method allows various advantages of the device according to the first aspect to be realised.

[0035] Optionally, in the method according to the second aspect, the battery characteristic model indicates correspondences between states of charge of the battery, internal resistance values of the battery and open circuit voltage values of the battery. Optionally, the method according to the second aspect comprises: inputting an internal resistance value of the battery and a voltage drop state of the battery into the current determination model; and obtaining the electrical current magnitude as an output from the current determination model.

[0036] Brief Description of the Drawings

[0037] Examples of the present disclosure will now be described with reference to the accompanying drawings.AL Ref: P47025WO | JTI Ref: 6838 6

[0038] Figure 1 is a first simplified schematic sketch of an aerosol generation device, according to examples;

[0039] Figure 2 is a table showing example correspondences indicated by a battery characteristic model, according to examples; and

[0040] Figure 3 is a second simplified schematic sketch of the aerosol generation device, according to examples.

[0041] Detailed Description

[0042] As used herein, the term “aerosol precursor material”, “vapour precursor material” or “vaporizable material” are used synonymously and may refer to a material and / or composition, which may for example comprise nicotine, cellulose-based sheet material, paper, tobacco, rye, or one or more herbs or botanicals in addition to a vaporising agent. The aerosol precursor material is configured to release an aerosol when heated or otherwise mechanically stimulated (such as by vibrations). Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and / or reconstituted tobacco in any one of shredded, crimped or gathered reconstituted tobacco sheet form. Nicotine may be in the form of nicotine salts. Rye may be in the form of various materials such as shredded rye, granulated rye, rye leaf and / or reconstituted rye. Suitable vaporising agents include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some examples, the aerosol precursor material may comprise a liquid or a gel, which may comprise nicotine and / or one or more solid particles. For example, the aerosol precursor material comprises tobacco particles suspended in a solution or gel.

[0043] An aerosol generation device is configured to aerosolise an aerosol precursor material without combustion in order to facilitate delivery of an aerosol to a user. Furthermore, and as is common in the technical field, the terms “vapour” and “aerosol”, and related terms such as “vaporize”, “volatilize” and “aerosolise”, may generally be used interchangeably.AL Ref: P47025WO | JTI Ref: 6838 7

[0044] As used herein, the term “aerosol generation device” is synonymous with “aerosol generating device” or “device” and may include a device configured to heat an aerosol precursor material and deliver an aerosol to a user, typically without combusting the aerosol precursor material. The aerosol generating device may comprise a heat provision system, e.g. a resistive or induction or photonic heating element, intended to heat the aerosol precursor material that can be at least in part inserted into the aerosol generating device. The aerosol generating device may also comprise a chamber for housing at least part of the aerosol precursor material for example arranged in aerosol generating article, such as a stick or a capsule or a pod. The device may be portable. “Portable” may refer to the device being for use when held by a user. The device may be adapted to generate a variable amount of aerosol, which can be controlled by a user input.

[0045] As used herein, the term “aerosol” may include a suspension of vaporizable material as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to / include a vapour. Aerosol may include one or more components of the vaporizable material.

[0046] In examples, there is provided an aerosol generation device configured to implement a current protection scheme. The aerosol generation device is for implementing a current protection scheme and comprises a circuit, arranged to receive electrical power from a battery. The aerosol generation device also comprises a processor configured to determine an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery. Determination of the electrical current magnitude allow various actions to be performed on the basis of the electrical current behaviour in the aerosol generation device.

[0047] Figure 1 is a first simplified schematic sketch of an aerosol generation device 100, according to examples. In these examples, there is shown the battery 102 which is provided in the aerosol generation device 100, and electrically connected to the circuit 104. The electrical circuit 104 is arranged to receive electrical power from the battery 102.

[0048] In these examples, the aerosol generation device 100 also comprises the processor 106. The processor 106 is configured to perform various processing tasks in relation to the functioning of the aerosol generation device 100. The processor 106 isAL Ref: P47025WO | JTI Ref: 6838 8

[0049] configured to determine an electrical current magnitude in the circuit 104 using a current determination model and a battery characteristic model of the battery 102.

[0050] Advantageously, the processor 106 is therefore configured to determine the electrical current magnitude in a manner that does not use a current sensor, for example. Those skilled in the art will appreciate that measuring voltage is generally faster than measuring current using instrumentation. That is because it is generally faster to load an electrical component having ohmic resistance with voltage than current. Measuring current typically involves breaking the circuit in question and inserting a small resistance into the current path, which is more intrusive and also less efficient in terms of power consumption.

[0051] In addition, accurate and fast determination of current allows for implementation of current protection schemes, which also extends the life of the battery 102. Another advantage is the avoidance of electronic component damage, e.g., which may otherwise result from overcurrent or short circuit conditions. In some examples, if a heat provision arrangement 304 (shown in Figure 3 introduced below) draws too much current, there may be heat damage which can also be avoided. Furthermore, occurrence of undesired current condition may indicate that a battery replacement should be performed. In these examples, a battery replacement notification may be provided to the user (e.g., via a visual, audio or other user interface mechanism).

[0052] In many applications, it is advantageous to determine the current magnitude in a circuit faster. This is especially the case where it is desired to implement some kind of current protection, such as protection against a component drawing too much current, or a short circuit condition.

[0053] Aerosol generation devices are handheld devices which typically comprise a heat provision system. In the case of a resistive heating element for example, the resistive heating element drawing excess current may negatively impact the comfort of using such a handheld device. Accordingly, determining an electrical current magnitude according to the examples described herein is particularly advantageous for aerosol generation devices.

[0054] For example, the current determination model, when used by the processor 106, allows the processor 106 to output an electrical current magnitude value for the circuit 104AL Ref: P47025WO | JTI Ref: 6838 9

[0055] when given a set of inputs. In some examples, the processor 106 is configured to input an internal resistance value of the battery 102 and a voltage drop state of the battery 102 into the current determination model. In these examples, the processor 106 is configured to obtain the electrical current magnitude as an output from the current determination model.

[0056] For example, the processor 106 may be configured to determine the voltage drop state of the battery 102 at the time when the determination is being performed. In some examples, the processor 102 is configured to determine an open circuit voltage of the battery 102 and a loaded voltage of the battery 102. In this case, the processor 106 determines the voltage drop state based on the determined open circuit voltage and the loaded voltage.

[0057] For example, the voltage drop state is taken as the difference between the open circuit voltage and the loaded voltage. When the voltage drop state is available, the voltage drop state and the internal resistance value can be input into the current determination model to output the electrical current magnitude. The current determination model may be expressed by Equation (1) below.

[0058] , . , . open circuit voltaqe-loaded voltaqe electrical current magnitude = - (1) internal resistance value

[0059] The numerator on the right-hand-side of Equation (1) corresponds to the voltage drop state, as will be appreciated from the preceding description.

[0060] As previously described, the electrical current magnitude is determined not only on the basis of the current determination model, but also on the basis of the battery characteristic model. For example, the battery characteristic model assists in providing one or more of the inputs which go into the current determination model (as expressed by Equation (1), for example). For example, the battery characteristic model indicates a relationship, a trend, or the like, of the battery which influences the inputs into the Equation (1).

[0061] In some examples, the battery characteristic model indicates a variation of internal resistance of the battery 102. It will be appreciated from the above description that to obtain a relatively accurate value of the electrical current magnitude, a relativelyAL Ref: P47025WO | JTI Ref: 6838 10

[0062] accurate internal resistance value ought to be used. Therefore, it is advantageous to take account of variations in the internal resistance of the battery 102.

[0063] For example, the internal resistance value may vary depending upon various conditions relating to the battery 102. In some examples, the internal resistance value of the battery 102 depends on the state of charge of the battery 102. For example, the state of charge of the battery 102 can be expressed as a percentage of the battery capacity still remaining. In other words, the state of charge indicates how much (as a percentage) of the battery is left. Accordingly, in some examples, the battery characteristic model indicates a correspondence between a state of charge of the battery 102 and a respective internal resistance value of the battery 102.

[0064] For example, the battery characteristic model indicates internal resistance values for a range of states of charge of the battery 102. Depending on the uses that are made of the determined electrical current magnitude, it may be desired to monitor relatively small changes in the electrical current magnitude. If it is desired to monitor such relatively small changes in the electrical current magnitude, then the battery characteristic model may indicate correspondingly small changes in the internal resistance value. In other words, if detection of small differences in the electrical current magnitude are desired, then the difference between internal resistance values indicated by the battery characteristic model may be correspondingly small. In other words, it may be desirable that the battery characteristic model indicates a large number of internal resistance values at relatively small intervals. In this way, when there is a small change in the internal resistance value, a small change in the electrical current magnitude can be determined.

[0065] For example, when the processor 106 determines the electrical current magnitude, the processor 106 accesses the battery characteristic model and obtains an internal resistance value based on the current state of charge of the battery 102. It will be appreciated by those skilled in the art that processors of handheld devices are able to determine the state of charge of the battery powering said hand-held device, and a description of the related methods is not provided herein.

[0066] Advantageously, simply by providing an appropriate battery characteristic model, internal resistance values can be provided with such a granularity such that the accuracy of the determined electrical current magnitude is improved. Those skilled inAL Ref: P47025WO | JTI Ref: 6838 11

[0067] the art will appreciate that the accuracy of a determined value relates to how close said determined value is to the true value. For example, by using a more accurate internal resistance value, a more accurate electrical current magnitude can be determined using the current determination model.

[0068] In these examples, accuracy is enhanced simply and surprisingly by the content of the battery characteristic model. This is an enhancement as compared to, for example, deploying more accurate current measurement instrumentation. Such more accurate current measurement instrumentation has cost and other implications which can be avoided by deploying the features described herein.

[0069] In some examples, the battery characteristic model indicates correspondences between states of charge of the battery 102, internal resistance values of the battery 102, and open circuit voltage values of the battery 102. As previously described, the open circuit voltage of the battery 102 may be an input into the current determination model, for example, as expressed by Equation (1).

[0070] The open circuit voltage of the battery 102 may also vary depending upon the state of charge of the battery 102. Therefore, it is advantageous to use a value of the open circuit voltage as an input into Equation (1) which takes account of the current state of charge of the battery 102, rather than a fixed value for example. In this manner, a more accurate value for the open circuit voltage is used, which further enhances the accuracy of the determine electrical current magnitude. The battery characteristic model may indicate a large number of open circuit voltage values at relatively small intervals, as described above in the case of the internal resistance values.

[0071] Figure 2 is a table showing example correspondences indicated by the battery characteristic model, according to examples. In the examples of Figure 2, there are shown values of the state of charge of the battery 102 at intervals of 0.5%. For each charge state, there is provided a corresponding open circuit voltage value and an internal resistance value. It should be appreciated that the examples of Figure 2 show only some of the states of charge and associated correspondences which may be included as part of the battery characteristic model. In some examples, the correspondences shown in Figure 2 may be stored in a computer readable memory which is in data communication with the processor 106. For example, theAL Ref: P47025WO | JTI Ref: 6838 12

[0072] correspondences may be stored in the form of one or more look-up-tables in the computer readable memory.

[0073] In some examples, the battery characteristic model includes correspondences, such as those shown in the look-up-table of Figure 2, for a number of age ranges of the battery 102. As will be appreciated from the description herein, a correspondence is an association of a given state of charge with a given internal resistance value and a given open circuit voltage value, for example. For example, the characteristics of the battery may change with the age of the battery 102. For example, the age of the battery 102 may be characterised by the number of charge cycles undergone. As a simplified example with simple numbers, there may be one set of correspondences (e.g., between state of charge and internal resistance, between charge state, internal resistance and open circuit voltage, etc.) for the first 0 to 100 charge cycles, a second set of correspondences for a battery age between 100 and 200 charge cycles, and so on. In this manner, accuracy of the current determination may be maintained through the usable life of the battery 102 and / or the aerosol generation device 100.

[0074] In some examples, the battery characteristic model is developed and stored in a memory of the aerosol generation device 100 before the aerosol generation device 100 is supplied to a user. For example, various battery characteristics may be determined (e.g., measured) for use as part of the battery characteristic model prior to, or as part of the manufacture process for the aerosol generation device 100. In some examples, where a number of substantially (with acceptable tolerances, e.g., manufacturing tolerances) identical batteries are deployed, only a subset of said batteries may be characterised in this manner on the basis that the battery characteristic model is valid for the whole set of the substantially identical batteries. In examples where the battery characteristic model includes correspondences for various age ranges of the battery, it will be appreciated that the individual / actual batteries on which the characterisation takes place would not be deployed in aerosol generation device - instead substantially identical new batteries (which have not undergone many charge cycles) may be deployed. In some examples, the battery characteristic model may be provided by the manufacturer of the battery 102.

[0075] In some examples, the battery characteristic model may be developed and / or supplemented once the aerosol generation device 100 has been supplied to its user. For example, these processes may take place as a set up procedure (e.g., a guidedAL Ref: P47025WO | JTI Ref: 6838 13

[0076] setup procedure) when the user first attempts to use the aerosol generation device. In some examples, these processes may take place at various points during the life of the aerosol generation device.

[0077] For example, appropriate instrumentation and / or circuitry may be provided to sense the internal resistance of the battery 102. As described later, the aerosol generation device may also comprise a voltage measurement system, which may be used to sense open circuit voltage values of the battery 102. For example, these pieces of data may be sensed at appropriate intervals of state of charge of the battery 102 in order to develop or update the battery characteristic model. It will be appreciated that the battery 102 may slowly deplete when the aerosol generation device 100 is not being used. Sensed data may be collected at such times to develop or update the battery characteristic model. As referred to herein, to develop the battery characteristic model refers to creating the data structure corresponding to the battery characteristic model where it did not exist before. On the other hand, updating the model means to change values which exist within the battery characteristic model to more up to date values.

[0078] Those skilled in the art will appreciate that the open circuit voltage of a battery is the voltage across said battery when no load is connected to said battery. As previously described, the processor 106 may be configured to determine the open circuit voltage and the loaded voltage of the battery 102. In some such examples, the open circuit voltage is obtained from the battery characteristic model. For example, the processor 106 accesses the battery characteristic model and obtains a value for the open circuit voltage based on the current state of charge of the battery 102 (and, in some examples, also based on the age of the battery 102).

[0079] In these examples, the processor 106 inputs the open circuit voltage obtained in this manner into the current determination model in order to determine the electrical current magnitude (together with the other desired inputs).

[0080] In some examples, the aerosol generation device 100 comprises a voltage measurement system configured to measure a voltage value across the battery 102. It will be appreciated from the specific example of Equation (1) above that the loaded voltage of the battery 102 may also be an input into the current determination model. In these examples, the processor 106 may be configured to determine the loaded voltage based on a measurement obtained from the voltage measurement system whenAL Ref: P47025WO | JTI Ref: 6838 14

[0081] the battery is connected to deliver electrical power to the circuit. For example, the voltage measurement system may not initiate measurements (e.g., repeated or continuous measurements for the purpose of live monitoring) at the start of a puff taken by the user from the aerosol generation device 100, or otherwise use measurements corresponding to the start of a puff. That is because it may be desired to avoid the associated peak measurements. For example, the start of a puff may be considered as a high current event (note that a short circuit may also be considered a high current event) which lasts for a short period of time. For example, when considering the battery voltage, a sharp negative peak (or drop) is expected to be seen at the start of a puff. This may, for example, occur due to the switching of electrical loads and the like. Such a sharp drop at the start of a puff, however, does not represent a short circuit condition for example. This voltage behaviour corresponding to the start of a puff may therefore be disregarded for the purpose of the monitoring of the electrical current.

[0082] Those skilled in the art will appreciate that there is a voltage drop across a battery when a load is applied. In other words, when the battery is connected in a circuit with electronic components which draw electrical power, the voltage across the battery drops to an amount lower than the open circuit voltage of the battery.

[0083] Figure 3 is a second simplified schematic sketch of the aerosol generation device 100, according to examples. In these examples, there is shown the voltage measurement system 302. In these examples, the voltage measurement system 302 is provided to measure the voltage across the battery 102 so that the voltage drop can be determined. As discussed above, the battery characteristic model may indicate the relevant value of the open circuit voltage, and said value from the battery characteristic model may be used as an input. However, in some other examples, the open circuit voltage of the battery 102 may be determined by virtue of measurements performed by the voltage measurement system 302 (for example, by opening the circuit such that the battery 102 is not connected to any load).

[0084] The voltage measurement system 302 may be any kind of arrangement capable of obtaining voltage measurements suitable for hand-held devices such as the aerosol generation device 100 described herein. For example, the voltage measurement system 302 may comprise instrumentation which is of a size appropriate for the aerosol generation device 100. For example, the voltage measurement system 302 may comprise circuitry for obtaining voltage measurements.AL Ref: P47025WO | JTI Ref: 6838 15

[0085] In these examples, using the combination of the battery characteristic model and measurements from the voltage measurement system 302 provides all the desired inputs for the current determination model as expressed by Equation (1) above.

[0086] As described above, a value to be used as input for the open circuit voltage is obtained from the battery characteristic model or appropriate measurements from the voltage measurement system 302. In either case, a current value of the loaded voltage across the battery 102 is obtained using the voltage measurement system 302, and subtracted from the open circuit voltage value to obtain the current voltage drop. The voltage drop determined in this manner is used in the current determination model.

[0087] It should be noted that the voltage drop across the battery 102, when the battery 102 is connected to the circuit 104 to supply power to electronic components, is expected to vary with time (e.g., during a session of use of the aerosol generation device 100). For example, during use, different electronic components may be deployed and draw electrical energy to various degrees. Such deployment of electronic components is controlled, for example, by the processor 106.

[0088] In the examples of Figure 3, there is provided a heat provision arrangement 304. The heat provision arrangement 304 is configured to provide heat for the generation of aerosol from an aerosol generation precursor material. The heat provision arrangement 304 is an example of an electronic component of the aerosol generation device 100 to which electrical power is delivered from the battery 102. In some examples, the heat provision arrangement 304 comprises a resistive heater. Those skilled in the art will appreciate that various kinds of heat provision arrangements are possible. For example, inductive heating can be used. In the case of inductive heating a varying magnetic field is generated via an A.C. current in induction coils, and the varying magnetic field causes Eddie currents in a susceptor material to thereby resistively heat the susceptor material.

[0089] Whichever kind of heat provision arrangement is deployed, it remains the case that the heat provision arrangement 304 draws electrical power (i.e. , acts as a load in the circuit 104), causing a voltage drop. The heat provision arrangement 304 is used herein as an example because the demand for heat provision typically varies as an aerosol inhalation session progresses.AL Ref: P47025WO | JTI Ref: 6838 16

[0090] The processor 106 may be configured to monitor the electrical current magnitude in the circuit 104 substantially in real time. For example, the processor 106 may constantly (in other words, repeatedly) determine the electrical current magnitude (using any of the examples described herein) at a fast rate. For example, the rate of determination is fast enough so that an undesirable current state can be determined quickly enough to implement a protection mechanism in a desired manner. Further description of the rate at which the processor performs the determination of the electrical current magnitude and other associated steps in monitoring the current is provided further below.

[0091] For example, it may be desired that the current drawn by the heat provision arrangement 304 does not exceed a particular amount. For example, excess current draw by the heat provision arrangement 304 may result in excess heat which may adversely affect surrounding components and / or the user’s comfort and / or experience. In some examples, short-circuit situations also have a possibility of arising. Accordingly, the processor 106 may be configured to take certain actions based on the electrical current reaching or exceeding one or more thresholds.

[0092] For example, there may be a current protection threshold. For example, the current protection threshold may be set at a value according to a maximum current it is desired for any electronic component to draw. For example, the current protection threshold may be set according to a maximum amount of current it is desired for the heat provision arrangement 304 to draw.

[0093] The current protection threshold may be at or slightly below the maximum amount of current it is desired for the electronic components connected to the circuit 104 (e.g., including the heat provision arrangement 304) to draw. In some specific examples, the maximum desired current may be 5 Amps (A), on the basis that this much current in the circuit 104 may cause the heat provision arrangement 304 to generate too much heat compared to a maximum desired amount. Such a maximum current being exceeded may be referred to as an overcurrent condition. In this case, the current protection threshold may be set at 5A or slightly below 5A. How far below 5A the current protection threshold is set in this example may depend, for example, on the rate of determination of the electrical current magnitude. The rate of determination of the electrical current magnitude by the processor 106 may be referred to as the determination rate hereafter,AL Ref: P47025WO | JTI Ref: 6838 17

[0094] for brevity. As referred to herein, the determination rate refers to the number of times an electrical current magnitude value is determined by the processor 106 per unit time (e.g., per second).

[0095] For example, the determination rate should be fast enough so that when a current protection situation is about to arise, the processor 106 has advance warning to implement a protection mechanism. For example, the determination rate may be faster (or at least similar to) an expected rate of increase of current during a current protection situation. If the determination rate is too slow, a first electrical current magnitude value may be a nominal value whereas the very next value may already be above the current protection threshold. It will be realised from the description herein that calibrations may take place during the design / manufacture of the aerosol generation device 100 to determine how fast the current in the circuit 104 can possibly ramp up into a current protection situation.

[0096] However, it should also be noted that very fast increases in current are possible, depending on the electronic component connected to the circuit 104. For example, if a determination rate equal to or faster than the fastest possible current increase is not possible (e.g., due to voltage detection system and / or processor speeds and the like), an advantage is still gained by being able to set a fast determination rate as compared to using current sensing instrumentation. More up to date current information is advantageously available more often by deploying the features disclosed herein.

[0097] As referred to herein, a current protection situation is a prevailing state in the circuit 104 in which the electrical current magnitude is on a trajectory to, or already has, exceeded the maximum amount of current desired in the circuit 104.

[0098] In some examples, the aerosol generation device comprises a cutoff mechanism configured to disconnect the battery 102 from the circuit 104. In the examples of Figure 3, there is shown the cutoff mechanism 306. For example, the cutoff mechanism may be one or more mechanical or electronic switches. For the aerosol generation device 100, which is a handheld device, electronic switches may be preferred due to their size efficiency. Also, for example, electronic switches may also be preferred due to their ability to respond faster than mechanical switches. In some examples, the cutoff mechanism 306 comprises a metal-oxide-semiconductor field-effect transistorAL Ref: P47025WO | JTI Ref: 6838 18

[0099] (MOSFET), however, the present disclosure is not limited to this. For example, other kinds of field effect transistors or other electronic switches may be deployed.

[0100] In the above description, reference is made to a protection mechanism implemented by the processor 106. The cutoff mechanism 306 of these examples functions as that protection mechanism.

[0101] In these examples, the processor 106 is configured to compare the determined electrical current magnitude to at least one current protection threshold, and trigger the cutoff mechanism 306 if the determined electrical current magnitude reaches or exceeds the current protection threshold. In the above description, reference is made to the current protection threshold relating to the maximum amount of current it is desired for the electronic components connected to the circuit 104 (e.g., including the heat provision arrangement 304) to draw. Such a current protection threshold may be referred to as an overcurrent threshold (given that it relates to avoiding too much current in the circuit 104 due to one or more electronic components drawing too much current). However, the current protection threshold may be set differently. For example, the current protection threshold may be something other than an overcurrent threshold. For example, the current protection threshold may be intended to protect against a short circuit condition.

[0102] For example, those skilled in the art will appreciate that a short circuit condition is when the electrical current takes an unintended path which causes there to be too much current flowing in the circuit in question. In some examples, the current protection threshold relating to short circuit protection may be set at a different level to the above examples relating to overcurrent condition. The current protection threshold relating to a short circuit condition may be referred to as the short circuit threshold. For example, the short circuit condition may be identified at a different current magnitude than the overcurrent condition (for example, 15A as opposed to 5A mentioned above).

[0103] In some examples, more than one current protection threshold may be used. For example, rather than one of the overcurrent threshold and the short circuit threshold being used, both of these thresholds may be used. Those skilled in the art will realise from the present description that there may be various conditions as regards the electrical current magnitude in the circuit 104 against which protection may be desired, and one or more current protection thresholds may be set accordingly. It should beAL Ref: P47025WO | JTI Ref: 6838 19

[0104] appreciated that one or more current protection thresholds may depend on the particular electronic components connected to the circuit 104.

[0105] As described above, the processor 106 is configured to trigger the cutoff mechanism 306 if the determined electrical current magnitude reaches or exceeds the current protection threshold. In this manner, specific undesired current conditions within the aerosol generation device 100 can be avoided. For example, triggering the cutoff mechanism 306 may cutoff current supply to one or more electrical components of the aerosol generation device (such as, for example, the heat provision arrangement), or may shut down the aerosol generation device altogether, depending on the desired protection configuration.

[0106] In examples where more than one current protection threshold is used, different protection processes may be implemented depending on which of the current protection thresholds is reached. For example, the processor 106 may operate the current protection mechanism 306 to cutoff current to the heat provision arrangement 304 if the overcurrent threshold is reached. On the other hand, the processor 106 may operate the current protection mechanism 306 to power down the aerosol generation device 100 if the short circuit threshold is reached. For example, it may be appropriate to shut down the device if the short circuit threshold is reached and there is no aerosol precursor material in the aerosol generation device 100 to be heated, as this may indicate that the short circuit is caused by other internal components of the aerosol generation device 100.

[0107] In some examples, the aerosol generation device 100 may comprise a user notification system (for example, a display screen, an audio notification system, a haptic notification system and the like), and the user notification system may provide a different notification depending upon which threshold is reached. The described cutoff of the heat provision arrangement 304 or the device 100 as whole, and / or the provision of notifications are merely examples, and various different current protections processes may be implemented by the processor 104 as desired. Furthermore, the aerosol generation device 100 comprising a user notification system may be combined with any of the described features of the aerosol generation device 100 and is not limited specifically to the implementation of more than one current protection thresholds.AL Ref: P47025WO | JTI Ref: 6838 20

[0108] As described above, the processor 106 may determine the electrical current magnitude at an appropriately fast rate. In some examples, the processor 106 implements an iterative process in order to monitor the electrical current magnitude in real time. For example, the processor 106 may be configured iteratively to: i) determine the electrical current magnitude in the circuit 104, and ii) compare the determined electrical current magnitude to the one or more electrical current thresholds. For example, the processor 106 may continue the iterations of determination and comparison until the cutoff mechanism 306 is triggered. For example, the fast rate referred to herein may apply not just to the determination of the electrical current magnitude, but also to the comparison of the determined electrical current magnitude to the relevant threshold in addition. For example, the processor 106 performs both steps i) and ii) consecutively (i.e. , the complete iteration) and at said fast rate. Such a rate may be referred to as the iteration rate.

[0109] In this manner, a current protection scheme may advantageously be implemented. In some examples, the iteration rate may be varied depending upon a particular phase of an inhalation session for which the aerosol generation device 100 is being used. In some examples, the iterations may not be implemented throughout the entirety of the inhalation session, but only during one or more specific parts of the inhalation session. For example, the iterations may be implemented when the heat provision arrangement 304 is active (i.e., using electrical power to generate heat).

[0110] For example, circumstances may arise in which the cutoff mechanism is triggered. In some examples, the processor 106 may be configured to reinitiate the iterations of processes i) and ii) when the cutoff mechanism 306 is deactivated after being triggered. Deactivating the cutoff mechanism 306 means that the cutoff mechanism 306 does not have the battery 102 disconnected from the circuit 104 or certain electronic components. Accordingly, normal operation of the aerosol generation device 100 may resume.

[0111] Advantageously, all the various examples described herein, provide an aerosol generation device in which the electrical current magnitude can be determined in a way that is accurate and fast, e.g., faster than current detection instrumentation may allow. Based on such real time current measurements, effective current protection schemes can be implemented.AL Ref: P47025WO | JTI Ref: 6838 21

[0112] There may be provided a method of implementing a current protection scheme in an aerosol generation device which comprises a circuit, and a battery configured to deliver electrical power to the circuit, and a processor. For example, the method comprises determining, via the processor, an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery. For example, the aerosol generation device on which said method is deployed is the aerosol generation device 100 according to any of the described examples.

[0113] In some examples of the method, the battery characteristic model indicates correspondences between states of charge of the battery, internal resistance values of the battery and open circuit voltage values of the battery. For example, the battery characteristic model used in the method may be the battery characteristic model according to any of the above-described examples.

[0114] Although preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above.

Claims

AL Ref: P47025WO | JTI Ref: 6838 22CLAIMS1. An aerosol generation device for implementing a current protection scheme, comprising:a circuit, arranged to receive electrical power from a battery; anda processor configured to:determine an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery.

2. The aerosol generation device according to claim 1 , wherein:the battery characteristic model indicates a variation of internal resistance of the battery.

3. The aerosol generation device according to claim 2, wherein:the battery characteristic model indicates a correspondence between a state of charge of the battery and a respective internal resistance value of the battery.

4. The aerosol generation device according to claim 3, wherein:the battery characteristic model indicates correspondences between states of charge of the battery, internal resistance values of the battery and open circuit voltage values of the battery.

5. The aerosol generation device according to any one of the preceding claims, wherein the processor is configured to:input an internal resistance value of the battery and a voltage drop state of the battery into the current determination model; andobtain the electrical current magnitude as an output from the current determination model.

6. The aerosol generation device according to claim 5, wherein the processor is configured to:determine an open circuit voltage of the battery and a loaded voltage of the battery; anddetermine the voltage drop state based on the determined open circuit voltage and the loaded voltage.AL Ref: P47025WO | JTI Ref: 6838 237. The aerosol generation device according to claim 6, wherein:the open circuit voltage is obtained from the battery characteristic model.

8. The aerosol generation device according to claim 6 or claim 7, comprising: a voltage measurement system configured to measure a voltage value across the battery,wherein, the processor is configured to determine the loaded voltage based on a measurement obtained from the voltage measurement system when the battery is connected to deliver electrical power to the circuit.

9. The aerosol generation device according to any of the preceding claims, comprising:a cutoff mechanism configured to disconnect the battery from the circuit, wherein the processor is configured to:compare the determined electrical current magnitude to at least one current protection threshold; andtrigger the cutoff mechanism if the determined electrical current magnitude reaches or exceeds the one or more current protection threshold.

10. The aerosol generation device according to claim 9, wherein the processor is configured iteratively to:i) determine the electrical current magnitude in the circuit; andii) compare the determined electrical current magnitude to the one or more current protection threshold,until the cutoff mechanism is triggered.

11. The aerosol generation device according to claim 10, wherein the processor is configured to:reinitiate the iterations of processes i) and ii) when the cutoff mechanism is deactivated after being triggered.

12. The aerosol generation device according to any one of claims 9 to 11, wherein:the cutoff mechanism comprises a MOSFET.

13. A method of implementing a current protection scheme in an aerosol generation device, wherein the aerosol generation device comprises a circuit, and a batteryAL Ref: P47025WO | JTI Ref: 6838 24configured to deliver electrical power to the circuit, and a processor, the method comprising:determining, via the processor, an electrical current magnitude in the circuit using a current determination model and a battery characteristic model of the battery.

14. The method according to claim 13, wherein:the battery characteristic model indicates correspondences between states of charge of the battery, internal resistance values of the battery and open circuit voltage values of the battery.

15. The method according to claim 13 or claim 14, comprising:inputting an internal resistance value of the battery and a voltage drop state of the battery into the current determination model; andobtaining the electrical current magnitude as an output from the current determination model.

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