Patent Publication Number: US-2019190088-A1

Title: E-cigarette and re-charging pack

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 15/326,592 filed Jan. 16, 2017, which in turn is a National Phase entry of PCT Application No. PCT/GB2015/052152, filed on 24 Jul. 2015, which claims priority to GB Patent Application No. 1413432.4, filed on 29 Jul. 2014, which are hereby fully incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates to an e-cigarette, such as an electronic vapor provision system or an electronic nicotine delivery system, and a re-charging pack for the e-cigarette. 
     BACKGROUND 
     Electronic vapor provision systems, electronic nicotine delivery systems, etc, which are collectively referred to herein as e-cigarettes, generally contain a reservoir of liquid which is to be vaporized. When a user sucks or draws on the device, this activates a heater to vaporize a small amount of liquid, which is then inhaled by the user. Most e-cigarettes include a re-chargeable battery for supplying electrical power to the heater and other electrical/electronic components, such as a sensor to detect inhalation. Some e-cigarettes have a cartridge section. After the nicotine or other liquid in this cartridge has been exhausted, the empty cartridge can be removed or separated from the e-cigarette and replaced with a new cartridge containing further nicotine. 
     E-cigarettes are often supplied in packs for protection and easy portability. Such packs may accommodate multiple e-cigarettes and/or replacement cartridges, thereby offering a backup facility if one e-cigarette (or its cartridge) is exhausted. An e-cigarette pack may also have the ability to re-charge an e-cigarette, again helping to ensure good operating availability of the e-cigarette for a user. Typically a pack is provided with a cylindrical hole for receiving an e-cigarette for recharging, the hole generally reflecting the elongated, cylindrical shape of an e-cigarette. When the e-cigarette is located in the hole, the battery can be re-charged by a suitable wired or wireless connection (a wireless connection may rely upon induction charging). In some packs, the cylindrical hole may receive the entire e-cigarette for re-charging, while in other packs only a portion of the e-cigarette may be received into the hole. 
     In some devices, the pack must be connected to a power supply, e.g. a mains outlet or USB connection, during re-charging of the e-cigarette battery. In this case, the pack is typically acting as a convenient device for holding and interfacing to the e-cigarette during re-charging. In other devices, the pack itself is provided with a battery (or other charge storage facility). The pack battery allows the e-cigarette to be re-charged from the pack without the need for the pack to be connected to an external power supply during the re-charging, thereby providing greater convenience for a user. 
     The pack battery will be depleted in due course, and so is generally provided with its own re-charging facility—typically again reliant upon some form of mains or USB connection. However, since the pack is larger than an e-cigarette, it can accommodate a larger battery and therefore the pack does not have to be re-charged as frequently as an e-cigarette. For example, the charge capacity of a typical e-cigarette battery may be approximately 60 mAh, whereas the charge capacity of a typical pack battery might be in the region of 800 mAh. Accordingly, the pack battery is capable of re-charging the e-cigarette a few times at least before the pack battery itself needs to be re-charged. 
     Such a multiple or hierarchical arrangement of separately chargeable systems, namely firstly an e-cigarette and secondly a pack for the e-cigarette, is relatively rare. In contrast, most re-chargeable devices, e.g. mobile (cell) phones, are usually connected directly to a mains-powered charging supply (or else to an in-car charging supply). 
     It is desirable for the operation and (re)charging of an e-cigarette and associated pack to be as safe, reliable and convenient for a user as possible. One potential concern relates to the lithium ion batteries that are used in many types of device, including e-cigarettes, because of their high energy density. If such a battery is defective, it may, on rare occasions, catch fire—see, for example, the news article dated 4 Feb. 2014 entitled “Batteries on planes pose ‘increased fire risk’” (http://www.bbc.co.uk/news/business-25733346). Although some existing e-cigarettes may incorporate certain safety features to address such issues, these have generally been incorporated in an ad hoc (rather than systematic) manner. 
     SUMMARY 
     A pack is provided for containing and recharging an e-cigarette. The pack comprises: a re-chargeable pack battery; a first connector which is electrically connectable to an external power source; a first recharging mechanism for re-charging the pack battery using the external power source when the first connector is electrically connected to the external power source; a second connector which is electrically connectable to an e-cigarette contained within the pack; and a second recharging mechanism for re-charging the e-cigarette when the e-cigarette is electrically connected to the second connector. The first recharging mechanism comprises a first protection circuit module for preventing electrical power flow from the external power source to the pack battery when the current supplied to the pack battery exceeds a first predetermined current threshold or the voltage supplied to the pack battery exceeds a first predetermined voltage threshold. The second re-charging mechanism comprises a second protection circuit module for preventing electrical power flow from the pack battery to the e-cigarette when the current supplied by the pack battery exceeds a second predetermined current threshold or the voltage supplied by the pack battery exceeds a second predetermined voltage threshold. 
     A rechargeable e-cigarette is provided comprising: a battery; a connector which is electrically connectable to an external battery pack; and a recharging mechanism for re-charging the battery using the external battery pack when the connector is electrically connected to the external battery pack. The recharging mechanism comprises a charge controller for controlling electrical power flow from the external battery pack to the battery; a temperature sensor which is response to the temperature of the battery; and a timer. The charging controller is configured to prevent electrical power flow from the external battery pack to the battery when the temperature of the battery is determined to lie outside a range defined between a lower temperature threshold and an upper temperature threshold. The timer is configured to start timing when electrical power starts flowing from the external battery pack to the battery and to prevent electrical power flow from the external battery pack to the battery after a predetermined time period has elapsed. 
     The present approach is not restricted to specific embodiments such as set out herein, but features from different embodiments may be combined, modified, omitted or replaced by the skilled person according to the circumstances of any given implementation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the disclosure will now be described in detail by way of example only with reference to the following drawings: 
         FIG. 1  is a schematic (exploded) diagram of an e-cigarette in accordance with some embodiments of the disclosure. 
         FIG. 2  is a schematic (simplified) diagram of a body of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 3  is a schematic diagram of a cartomizer of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 4  is a schematic diagram of certain details of a connector at one end of the body of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 5  illustrates a cap with a connector at another end of the body of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 6  is a schematic diagram of the main functional components of the body of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 7  illustrates a pack for receiving and accommodating an e-cigarette in accordance with some embodiments of the disclosure. 
         FIG. 8  illustrates the main components that are housed within the body of the pack of  FIG. 7  in accordance with some embodiments of the disclosure. 
         FIGS. 9A and 9B  illustrate (in an exploded view) an e-cigarette connection assembly  700  of the pack of  FIG. 7  in accordance with some embodiments of the disclosure. 
         FIG. 10  is a schematic diagram of safety components of the e-cigarette of  FIG. 1  in accordance with some embodiments of the disclosure. 
         FIG. 11  is a schematic diagram of safety components of the pack of  FIG. 7  in accordance with some embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic diagram of an electronic vapor provision system such as an e-cigarette  10  in accordance with some embodiments of the disclosure (not to scale). The e-cigarette  10  has a generally cylindrical shape, extending along a longitudinal axis indicated by dashed line LA, and comprises two main components, namely a body  20  and a cartomizer  30 . The cartomizer  30  includes an internal chamber containing a reservoir of nicotine, a vaporizer (such as a heater), and a mouthpiece  35 . The reservoir may be a foam matrix or any other structure for retaining the nicotine until such time that it is required to be delivered to the vaporizer. The cartomizer  30  also includes a heater for vaporizing the nicotine and may further include a wick or similar facility to transport a small amount of nicotine from the reservoir to a heating location on or adjacent the heater. 
     The body  20  includes a re-chargeable cell or battery to provide power to the e-cigarette  10  and a circuit board for generally controlling the e-cigarette  10 . When the heater receives power from the battery, as controlled by the circuit board, the heater vaporizes the nicotine and this vapor is then inhaled by a user through the mouthpiece. 
     The body  20  and cartomizer  30  are detachable from one another by separating in a direction parallel to the longitudinal axis LA, as shown in  FIG. 1 , but are joined together when the device  10  is in use by a connection, indicated schematically in  FIG. 1  as  25 A and  25 B, to provide mechanical and electrical connectivity between the body  20  and the cartomizer  30 . The electrical connector on the body  20  that is used to connect to the cartomizer  30  also serves as a socket for connecting a charging device (not shown) when the body  20  is detached from the cartomizer  30 . The other end of the charging device can be plugged into a USB socket to re-charge the cell in the body of the e-cigarette  10 . In other implementations, a cable may be provided for direct connection between the electrical connector on the body  20  and a USB socket. 
     The e-cigarette  10  is provided with one or more holes (not shown in  FIG. 1 ) for air inlet. These holes connect to an air passage through the e-cigarette  10  to the mouthpiece  35 . When a user inhales through the mouthpiece  35 , air is drawn into this air passage through the one or more air inlet holes, which are suitably located on the outside of the e-cigarette  10 . This airflow (or the resulting change in pressure) is detected by a pressure sensor that in turn activates the heater to vaporize the nicotine from the cartridge. The airflow passes through, and combines with, the nicotine vapor, and this combination of airflow and nicotine vapor then passes out of the mouthpiece  35  to be inhaled by a user. The cartomizer  30  may be detached from the body  20  and disposed of when the supply of nicotine is exhausted (and replaced with another cartomizer  30  if so desired). 
     It will be appreciated that the e-cigarette  10  shown in  FIG. 1  is presented by way of example, and various other implementations can be adopted. For example, in some embodiments, the cartomizer  30  is provided as two separable components, namely a cartridge comprising the nicotine reservoir and mouthpiece (which can be replaced when the nicotine from the reservoir is exhausted), and a vaporizer comprising a heater (which is generally retained). In other embodiments, the e-cigarette  10 , the body  20  and the cartomizer  30  may be joined together permanently, so in effect they are just a single component. Some such unitary (one-piece) e-cigarettes may allow replenishing of a nicotine reservoir when exhausted using some suitable (re)supply mechanism; other one-piece e-cigarettes may be disposed of once the nicotine reservoir has been exhausted. Note that this latter type of device still generally supports re-charging because the battery will normally become depleted more quickly than the nicotine reservoir. The skilled person will be aware of many further possible designs and implementations of an e-cigarette. 
       FIG. 2  is a schematic (simplified) diagram of the body  20  of the e-cigarette  10  of  FIG. 1  in accordance with some embodiments of the disclosure.  FIG. 2  can generally be regarded as a cross-section in a plane through the longitudinal axis LA of the e-cigarette  10 . Note that various components and details of the body  20 , e.g. such as wiring and more complex shaping, have been omitted from  FIG. 2  for reasons of clarity. 
     As shown in  FIG. 2 , the body  20  includes a battery or cell  210  for powering the e-cigarette  10 , as well as a chip, such as an application specific integrated circuit (ASIC) or microcontroller for controlling the e-cigarette  10 . The ASIC may be positioned alongside or at one end of the battery  210 . The ASIC is attached to a sensor unit  215  to detect an inhalation on mouthpiece  35  (or alternatively the sensor unit  215  may be provided on the ASIC itself). In response to such a detection, the ASIC provides power from the battery or cell  210  to a heater in the cartomizer to vaporize nicotine into the airflow which is inhaled by a user. 
     The body  20  further includes a cap  225  to seal and protect the far (distal) end of the e-cigarette  10 . There is an air inlet hole provided in or adjacent to the cap  225  to allow air to enter the body and flow past the sensor unit  215  when a user inhales on the mouthpiece  35 . This airflow therefore allows the sensor unit  215  to detect the user inhalation. The cap  225  may also comprise a pair of electrical contacts which allow the e-cigarette  10  to be charged using these electrical contacts (in addition to, or instead of, USB charging or the like using the connector  25 B). This is explained in more detail below. 
     At the opposite end of the body  20  from the cap  225  is the connector  25 B for joining the body  20  to the cartomizer  30 . The connector  25 B provides mechanical and electrical connectivity between the body  20  and the cartomizer  30 . The connector  25 B includes a body connector  240 , which is metallic (silver-plated in some embodiments) to serve as one terminal for electrical connection (positive or negative) to the cartomizer  30 . The connector  25 B further includes an electrical contact  250  to provide a second terminal for electrical connection to the cartomizer  30  of opposite polarity to the first terminal, namely body connector  240 . The electrical contact  250  is mounted on a coil spring  255 . When the body  20  is attached to the cartomizer  30 , the connector  25 A on the cartomizer  30  pushes against the electrical contact  250  in such a manner as to compress the coil spring in an axial direction, i.e. in a direction parallel to (co-aligned with) the longitudinal axis LA. In view of the resilient nature of the spring  255 , this compression biases the spring  255  to expand, which has the effect of pushing the electrical contact  250  firmly against connector  25 A, thereby helping to ensure good electrical connectivity between the body  20  and the cartomizer  30 . The body connector  240  and the electrical contact  250  are separated by a trestle  260 , which is made of a non-conductor (such as plastic) to provide good insulation between the two electrical terminals. The trestle  260  is shaped to assist with the mutual mechanical engagement of connectors  25 A and  25 B. 
       FIG. 3  is a schematic diagram of the cartomizer  30  of the e-cigarette  10  of  FIG. 1  in accordance with some embodiments of the disclosure.  FIG. 3  can generally be regarded as a cross-section in a plane through the longitudinal axis LA of the e-cigarette  10 . Note that various components and details of the body  20 , e.g. such as wiring and more complex shaping, have been omitted from  FIG. 3  for reasons of clarity. 
     The cartomizer  30  includes an air passage  355  extending along the central (longitudinal) axis of the cartomizer  30  from the mouthpiece  35  to the connector  25 A for joining the cartomizer  30  to the body  20 . A reservoir of nicotine  360  is provided around the air passage  335 . This reservoir  360  may be implemented, for example, by providing cotton or foam soaked in nicotine. The cartomizer  30  also includes a heater  365  for heating nicotine from reservoir  360  to generate nicotine vapor to flow through air passage  355  and out through mouthpiece  35  in response to a user inhaling on the e-cigarette  10 . The heater  365  is powered through lines  366  and  367 , which are in turn connected to opposing polarities (positive and negative, or vice versa) of the battery  210  via connector  25 A (the details of the wiring between the power lines  366  and  367  and connector  25 A are omitted from  FIG. 3 ). 
     The connector  25 A includes an inner electrode  375 , which may be silver-plated or made of some other suitable metal. When the cartomizer  30  is connected to the body  20 , the inner electrode  375  contacts the electrical contact  250  of the body  20  to provide a first electrical path between the cartomizer  30  and the body  20 . In particular, as the connectors  25 A and  25 B are engaged, the inner electrode  375  pushes against the electrical contact  250  so as to compress the coil spring  255 , thereby helping to ensure good electrical contact between the inner electrode  375  and the electrical contact  250 . 
     The inner electrode  375  is surrounded by an insulating ring  372 , which may be made of plastic, rubber, silicone, or any other suitable material. The insulating ring is surrounded by the cartomizer connector  370 , which may be silver-plated or made of some other suitable metal or conducting material. When the cartomizer  30  is connected to the body  20 , the cartomizer connector  370  contacts the body connector  240  of the body  20  to provide a second electrical path between the cartomizer  30  and the body  20 . In other words, the inner electrode  375  and the cartomizer connector  370  serve as positive and negative terminals (or vice versa) for supplying power from the battery  210  in the body  20  to the heater  365  in the cartomizer  30  via supply lines  366  and  367  as appropriate. 
     The cartomizer connector  370  is provided with two lugs or tabs  380 A,  380 B, which extend in opposite directions away from the longitudinal axis of the e-cigarette  10 . These tabs are used to provide a bayonet fitting in conjunction with the body connector  240  for connecting the cartomizer  30  to the body  20 . This bayonet fitting provides a secure and robust connection between the cartomizer  30  and the body  20 , so that the cartomizer  30  and body  20  are held in a fixed position relative to one another, without wobble or flexing, and the likelihood of any accidental disconnection is very small. At the same time, the bayonet fitting provides simple and rapid connection and disconnection by an insertion followed by a rotation for connection, and a rotation (in the reverse direction) followed by withdrawal for disconnection. It will be appreciated that other embodiments may use a different form of connection between the body  20  and the cartomizer  30 , such as a snap fit or a screw connection. 
       FIG. 4  is a schematic diagram of certain details of the connector  25 B at the end of the body  20  in accordance with some embodiments of the disclosure (but omitting for clarity most of the internal structure of the connector as shown in  FIG. 2 , such as trestle  260 ). In particular,  FIG. 4  shows the external housing  201  of the body  20 , which generally has the form of a cylindrical tube. This external housing  201  may comprise, for example, an inner tube of metal with an outer covering of paper or similar. 
     The body connector  240  extends from this external housing  201  of the body  20 . The body connector  240  as shown in  FIG. 4  comprises two main portions, a shaft portion  241  in the shape of a hollow cylindrical tube, which is sized to fit just inside the external housing  201  of the body  20 , and a lip portion  242  which is directed in a radially outward direction, away from the main longitudinal axis (LA) of the e-cigarette  10 . Surrounding the shaft portion  241  of the body connector  240 , where the shaft portion  241  does not overlap with the external housing  201 , is a collar or sleeve  290 , which is again in a shape of a cylindrical tube. The collar  290  is retained between the lip portion  242  of the body connector  240  and the external housing  201  of the body  20 , which together prevent movement of the collar  290  in an axial direction (i.e. parallel to axis LA). However, collar  290  may be free to rotate around the shaft portion  241  (and hence also axis LA). 
     As mentioned above, the cap  225  is provided with an air inlet hole to allow air to flow past sensor  215  when a user inhales on the mouthpiece  35 . However, the majority of air that enters the device when a user inhales flows through collar  290  and body connector  240  as indicated by the two arrows in  FIG. 4 . (The collar  290  and the body connector  240  are provided with holes, not shown in  FIG. 4 , to support such airflow.) 
       FIG. 5  shows the cap or tip  225  of the body  20  of the e-cigarette  10  in accordance with some embodiments of the disclosure. The cap  225  comprises a connector  900  comprising two electrical contacts  900 A,  900 B. The electrical contact  900 B is a circular point-type contact located at the center of the cap  225 . The electrical contact  900 A is a circular ring which is concentric with the contact  900 A and provided around the outside or rim of the cap  225 . It will, however, be appreciated that any other shape configuration of the electrical contacts could be used. The electrical contacts  900 A,  900 B are typically made of metal and are connectable to positive and negative electrical terminals of a recharging e-cigarette pack so as to (re)charge the e-cigarette  10  (as explained in more detail later on). The tip of the e-cigarette  10 , in particular connector  900 , may be covered by a user-removable protective tab or similar while shipping or before use to protect against the battery  210  accidentally discharging prior to first use by a consumer. This helps to ensure that the battery  210  is delivered in an acceptable state to the consumer, and also that damage which might be caused by heating due to unexpected current flows from the battery  210  is avoided. 
       FIG. 6  is a schematic diagram of the main functional components of the body  20  of the e-cigarette  10  of  FIG. 1  in accordance with some embodiments of the disclosure. These components may be mounted on the circuit board provided within the body  20 , although depending on the particular configuration, in some embodiments, one or more of the components may instead be accommodated in the body  20  to operate in conjunction with the circuit board, but is/are not physically mounted on the circuit board itself. 
     The body  20  includes the sensor unit  215  located in or adjacent to the air path through the body  20  from the air inlet to the air outlet (to the vaporizer). The sensor unit  215  includes a pressure drop sensor  562  and temperature sensor  563  (also in or adjacent to this air path). The body  20  further includes a small speaker  558  and an electrical socket or connector  25 B for connecting to the cartomizer  30  or to a USB charging device. (The body may also be provided with a tip connector  900 , such as discussed above in relation to  FIG. 5 .) 
     The microcontroller (e.g. an ASIC)  555  includes a CPU  550 . The operations of the CPU  550  and other electronic components, such as the pressure sensor  562 , are generally controlled at least in part by software programs running on the CPU  550  (or other component). Such software programs may be stored in non-volatile memory, such as ROM, which can be integrated into the microcontroller  555  itself, or provided as a separate component. The CPU  550  may access the ROM to load and execute individual software programs as and when required. The microcontroller  555  also contains appropriate communications interfaces (and control software) for communicating as appropriate with other devices in the body  10 , such as the pressure sensor  562 . 
     The CPU  550  controls the speaker  558  to produce audio output to reflect conditions or states within the e-cigarette  10 , such as a low battery warning. Different signals for signaling different states or conditions may be provided by utilizing tones or beeps of different pitch and/or duration, and/or by providing multiple such beeps or tones. The e-cigarette  10  may also be provided with an LED indicator (instead of or as well as speaker  558 ) to provide visual output to a user, such as a warning of low battery charge. 
     As noted above, the e-cigarette  10  provides an air path from the air inlet through the e-cigarette  10 , past the pressure drop sensor  562  and the heater (in the vaporizer or cartomizer  30 ), to the mouthpiece  35 . Thus when a user inhales on the mouthpiece of the e-cigarette  10 , the CPU  550  detects such inhalation based on information from the pressure drop sensor. In response to this detection, the CPU  550  supplies power from the battery or cell  210  to the heater, which thereby heats and vaporizes the nicotine from the wick for inhalation by the user. The level of power supplied to the heater may be controlled on the basis of information from the pressure sensor and/or the temperature sensor  563 , for example, to help regulate the nicotine delivery to the user according to the current ambient air pressure and temperature. 
       FIG. 7  illustrates a pack  100  for receiving and accommodating an e-cigarette  10  in accordance with some embodiments of the disclosure. The pack  100  comprises a body  120  which is provided with a hinged lid  140  that can open and close. The body  120  comprises an outer case or housing  125  which is fitted with an insert  130 . More particularly, the outer case  125  has an opening at the top, i.e. the end at which the lid is located, and the insert  130  is fitted into, and generally closes, this opening. The insert  130  itself is provided with two openings or holes that extend down into the body  120  of the pack  100 . The first opening  132  comprises a substantially circular hole (in terms of cross-sectional shape). The first opening  132  is surrounded by an annular light element  133 . The second opening  131  in the insert comprises a pair of linked holes (only one of which is easily visible in  FIG. 7 ). The openings  132  and  131  (and more particularly, each of the pair of holes formed by opening  131 ) can be used to receive an appropriately shaped object, such as an e-cigarette, a spare or used cartridge, etc. The dimensions of pack  100  are generally arranged so that an e-cigarette accommodated within openings  132  or  131  protrudes slightly out of this opening. This allows a user to readily discern the contents of pack  100  (as also helped by making lid  140  transparent), and also facilitates removal by a user of an e-cigarette located within one of these openings. 
     The pack  100  is further provided with a set of LED lights  128 . These are shown separated from the casing  125  in  FIG. 7  in an exploded view, but in the assembled pack  100  are integrated into the body  120  so as to lie flush with the outer casing  125 . These LED lights  128  can be used to indicate the charging state of the pack  100 , for example, whether it is fully charged, partly charged, or fully discharged. The LED lights  128  may also be used to indicate whether or not the pack  100  is currently charging (being charged). Such charging may be accomplished via a (mini or micro) USB link using a (mini or micro) USB connector located on the underside of the pack  100  (not visible in  FIG. 7 ). 
       FIG. 8  illustrates the main components that are housed within the body  120  of the pack  100 , more particularly, within housing  125 , in accordance with some embodiments of the disclosure (some minor components, such as internal wiring, are omitted for reasons of clarity). The body includes a battery unit  150  comprising a battery  151 , a printed circuit board (PCB)  154 , and a switch  152 . The body  120  can be seen to include a hinge or axle  134 , which provides a pivot about which the lid  140  is able to open and shut. The battery unit  150 , including the switch  152 , is located substantially below the hinge  134 . The switch  152  is activated as the lid  140  is opened or closed, and this activation of the switch  152  then, in turn, is able to trigger activation of the LED lights, etc. 
     As illustrated in  FIG. 8 , the insert  130  extends substantially to the bottom of the outer casing  125 . The insert defines a substantially cylindrical tube  132 A extending down from opening  132  (see  FIG. 7 ), which is able to receive and hold an e-cigarette. The insert further includes two further substantially cylindrical tubes  131 A,  131 B, which overlap one another, extending down from opening  131  (see  FIG. 7 ) with a “figure-of-8” cross-section. Note that the bottom of tubes  131 A and  131 B may be closed by the insert  130  itself, or may be open, but abutting against the bottom of the outer casing  125 , which would then have the effect of again closing the bottom of the tubes  131 A and  131 B in order to retain an e-cigarette (or other item, such as a spare cartridge, therein). The configuration of the bottom of the tube  132 A is explained in more detail later on. 
     Note that the battery  151  is relatively large—comparable in size, for example, with the opening  132  and associated tube  132 A for receiving an e-cigarette. Consequently the battery  151  of the pack  100  will usually have significantly greater electrical storage capacity than a battery provided in an e-cigarette which may be accommodated within the pack  100 . This allows the battery in the e-cigarette to be re-charged, typically several times, using the battery unit  150  of pack  100 , without the need for any additional, external power supply (such as a mains connection). This can be very convenient for a user, who may be in a location or situation which does not provide a ready connection to the mains power supply. 
     In order to support this re-charging of an e-cigarette stored within the pack  100 , the bottom portion of the tube  132 A is located within an e-cigarette connection assembly  700 . The e-cigarette connection assembly  700  allows an electrical connection to be made between the pack  100  and the electrical contacts  900 A,  900 B on the cap  225  of the e-cigarette  10  when the e-cigarette  10  is inserted into the tube  132 A, thus allowing the e-cigarette battery  210  to be charged using the pack battery  151 . This is explained in more detail below. 
     The insert  130  is provided with printed circuit boards (PCBs)  135  and  160 . The PCB  160  provides the main control functionality of the pack  100  and is attached to tubes  131 A,  131 B by screws  136 A,  136 B, thereby retaining the PCB  160  in the appropriate position relative to the tubes  131 A,  131 B. A mini-USB (or micro-USB) connector  164  is provided at the bottom of the PCB  160 , and is accessible through a corresponding aperture in the underside of the housing  125  of the pack body  120 . This USB connector  164  can be used to connect an external power supply to the pack  100  for re-charging the battery  151  (and also any e-cigarette located in tube  132 A). The USB connector  164  may also be used, if so desired, for communications with the electronics of the pack  100  and/or e-cigarette  10 , for example to update software on the PCB  160  and/or to download usage data from the e-cigarette  10 , etc. The PCB  160  is further provided with a set of physical and mechanical connectors  161  for retaining and operating the LED lighting  128 . In particular, the PCB  160  controls the LED lighting element  128  to provide an indication to a user about the current charging situation of the pack  100 , plus any other suitable information. 
     The PCB  135  is located on the outside of re-charging tube  132 A, relatively near the top, i.e. closer to the hole or opening  132  for receiving an e-cigarette for re-charging. This PCB  135  incorporates at least one light emitting diode (LED), which is used to illuminate the annular light element  133 . The PCB  135 , LED and annular light element  133  are used to provide an indication to a user about the current charging situation of an e-cigarette located within tube  132 A pack  100 , plus any other suitable information. 
       FIGS. 9A and 9B  show (in an exploded view) the e-cigarette connection assembly  700  in more detail in accordance with some embodiments of the disclosure. The e-cigarette connection assembly  700  comprises a base  702 , which is located on the base of the pack  100 , and a connector  703 , which has two electrical contacts  704 A,  704 B for making an electrical connection with the electrical contacts  900 A,  900 B on the cap  225  of the e-cigarette  10  when the e-cigarette  10  is inserted into the tube  132 A. Specifically, the outer electrical contact  704 A makes an electrical connection with electrical contact  900 A on the e-cigarette  10  and the inner electrical contact  704 B makes an electrical connection with the electrical contact  900 B on the e-cigarette  10 . The electrical contacts  704 A,  704 B are connected to the PCB  160  via wires  708 A,  708 B and, under the control of the PCB  160 , act as positive and negative electrodes for charging the e-cigarette  10  with power supplied from the battery  151 . The electrical contacts  704 A,  704 B are spring-mounted on the base  702  so as to ensure good electrical connection with the electrical contacts  900 A,  900 B on the cap  225  of the e-cigarette  10 . Electrical conductors connecting the electrical contacts  704 A,  704 B and the wires  708 A,  708 B may extend along the surface of the base  702  or may extend through a bore through the base  702 , for example. 
     The e-cigarette connection assembly  700  further comprises a cylindrical tube  706  which is fixed to the base  702 . A portion of the cylindrical tube  706  is configured to receive an end portion of the tube  132 A. The inner diameter of the portion of the cylindrical tube  706  which receives the end portion of the tube  132 A is set such that the outer surface of the end portion of the tube  132 A frictionally engages with the inner surface of the cylindrical tube  706 . The inner surface of the cylindrical tube  706  further comprises a rib  714  which abuts the end of the tube  132 A and ensures that only an end portion of the tube  132 A having a predetermined length is able to enter the cylindrical tube  706 . The cylindrical tube  706  further comprises a groove  710  on its outer surface which engages with a rib  712  on the PCB  160 . 
     When the insert  130  and e-cigarette connection assembly  700  are inserted into the outer case  125 , the base  702  abuts the bottom inner surface of the outer case  125 . The insert  130  and e-cigarette connection assembly  700  are held in place within the outer case  125  (and also in relation to one another). 
     It will be appreciated that the configuration and arrangement of the pack  100  and insert  130  shown in  FIGS. 7, 8 and 9  are provided by way of example, and the skilled person will be aware of many potential variations—e.g. the number, position, size and/or shape of holes  131 ,  132  may vary from one embodiment to another, likewise the associated tubes  131 A,  131 B,  132 A. Similarly, the details of the positioning, shape and size of the battery unit  150 , PCB  160 , and other components will generally vary from one embodiment to another, depending upon the particular circumstances and requirements of any given implementation. It is also noted that the shape and positioning of the electrical contacts  704 A,  704 B will be adapted according to different shape and positional configurations of electrical contacts  900 A,  900 B on the e-cigarette  10 . 
       FIGS. 10 and 11  schematically show some components of the e-cigarette  10  and pack  100 , respectively, in accordance with some embodiments of the disclosure. These components help to improve the safety and reliability of the various charging mechanisms provided for the e-cigarette  10  and pack  100 . 
       FIG. 10  schematically depicts some electrical components of the e-cigarette  10 . In addition to the connector  900 , battery  210  and connector  25 B, which have already been discussed in relation to  FIGS. 5 and 6 ,  FIG. 10  also shows a tip charge PCB  1002 , a temperature sensor  1006 , and an over-current protection PCB  1000 . It is noted that for the sake of clarity, not all electrical components of the e-cigarette  10  are included in  FIG. 10  e.g. some of the components already shown in  FIG. 6  have been omitted. 
     The over-current protection PCB  1000  monitors the current flowing through the connector  25 B during operation of the e-cigarette  10 . It is recalled that, during use of the e-cigarette  10 , the CPU  550  detects when a user is drawing air through the e-cigarette  10  using information from the sensor unit  215  and causes current to flow to the heater  365  in the cartomizer  30  via the connector  25 B. If there is a short circuit at the heater  365 , for example, there will be a sudden increase in current flowing through the heater  365  and connector  25 B. The short circuit might occur for reasons such as an electrical fault at the heater  365 , the heating circuit having been tampered with, excessive moisture making contact with the heater  365 , etc. A short circuit of the heater  365  may risk damage occurring to the e-cigarette device or, worse, injury to the user. 
     Accordingly, the over-current protection PCB  1000 , upon detection of a current through the connector  25 B which is deemed too high (that is, above a certain predetermined threshold), causes the supply of current from the battery  210  to the connector  25 B to be cut. This reduces the chance of damage to the e-cigarette  10  and of injury to the user due to such a short circuit. 
     The predetermined current threshold is set such that dangerously high currents indicative of a short circuit are cut off, but normal, non-dangerous variations in the current are not cut off (thus avoiding unnecessary inconvenience to the user). For example, the threshold for the current supply from the battery  210  to the heater  365  may be set somewhere in the range 40-250 milliAmps, or more precisely, in the range 60-120 milliAmps, such that any current greater than this threshold amount triggers a circuit cut off. 
     The PCB  1000  may also cut-off if the voltage of the battery  210  is too low, for example, below about 3.1 or 3.2V. This generally indicates that the battery  210  is in a state of low charge, and this could potentially prevent correct (or satisfactory) operation of the heater coil. 
     The over-current protection PCB  1000  may also monitor current flowing through the connector  25 B, and/or voltage applied at connector  25 B, during re-charging of the e-cigarette  10  via USB connector  25 B. For example, the expected voltage applied by a USB charger to the USB connector  25 B may be 5V, so that the over-voltage cut-off might be set, by way of illustration, at 6V. The over-current protection PCB  1000  therefore provides protection for the e-cigarette  10  both during re-charging (against excessive re-charging voltage), and also during normal operation (against excessive current draw). 
     The tip charge PCB  1002  acts as a controller for monitoring and controlling power flow from the pack  100  to the e-cigarette battery  210  during re-charging. For example, the tip charge PCB may cut off the power flow from the pack  100  to the battery  210  if the voltage and/or current received via connector  900  is too high—e.g. exceeds a predetermined threshold for voltage or current. The thresholds can be set to tolerate the full range of normal operating conditions, but to trigger (cut off) before a level that might start to cause damage to the e-cigarette  10 . 
     The tip charge PCB  1002  is connected to the temperature sensor  1006 . The temperature sensor  1006  is in thermal contact with the battery  210  so as to be responsive to the temperature of the battery  210 . (Thus temperature sensor  1006  is normally an additional device to temperature sensor  563  shown in  FIG. 6 , since the former is positioned to measure the temperature of the battery  210 , while the latter is positioned to measure the temperature of the airflow into the e-cigarette  10 .) 
     As the battery  210  is (re)charged using the connector  900  (that is, when the e-cigarette  10  is inserted into the tube  132 A of the pack  100  so that the connector  900  makes electrical contact with the connector  703  of the pack), the battery  210  will normally heat up. However, if the battery  210  gets too hot (perhaps due to a fault in the battery  210  or because the ambient temperature is very warm), this may cause damage to the e-cigarette  10 , to the pack  100  or, worse, injury to the user. Also, if the battery  210  is very cold (perhaps due to the ambient temperature being very cold), then attempting to charge the battery  210  may cause damage to it. Thus, the tip charge PCB  1002  monitors the temperature of the battery  210  using information generated by the temperature sensor  1006 . If the temperature gets too hot (that is, above a predetermined upper threshold) or too cold (that is, below a predetermined lower threshold), the tip charge PCB  1002  cuts off the current supply to the battery  210  from the connector  900 . This reduces the chance of damage to the e-cigarette  10  or pack  100  or of injury to the user due to the battery  210  overheating, as well as reducing the chance of damage to the battery  210  by charging it when it is too cold. 
     The predetermined upper temperature threshold is set such that high temperatures indicative of potential battery overheating result in current to the battery  210  being cut off, whereas lower increases in battery temperature do not result in the current to the battery  210  being cut off. Similarly, the predetermined lower temperature threshold is set such that low temperatures which could damage the battery  210  result in current to the battery  210  being cut off, whereas smaller reductions in battery temperature do not result in current to the battery  210  being cut off. Examples of the upper and lower temperature thresholds are about 60° C. and about 0° C., or about 45° C. and about 10° C., respectively. 
     The tip charging PCB  1002  also ensures that current is only supplied to the battery  210  for a predetermined time period before it is cut off. This ensures that the battery  210  is not subjected to overcharging, in which the battery  210  is continuously charged even though it is at full capacity (which might damage the battery  210 ). The predetermined time period is set so that the battery  210  can be charged to its full capacity (maximizing the length of time that the user can use the e-cigarette  10  without having to recharge it), but also avoiding overcharging of the battery  210 . For example, the predetermined time period may be set somewhere in the range 1 to 4 hours, such as between 1 and 2 hours. 
     Overall therefore, the over-current protection PCB  1000  and/or the tip charging PCB  1002  provide protection based on the parameters or dimensions set out below.
         time—there is a threshold for a maximum re-charge duration.   temperature—there are upper and lower thresholds for a maximum and minimum battery temperature respectively. These thresholds are applied in particular when battery  210  is being re-charged, but may also be applied during normal operation of the device—i.e. when the user is inhaling through e-cigarette  10  to activate heater  365  and produce vapor output.   voltage—there is a threshold for a maximum voltage applied during re-charge.   current—there is a threshold for a maximum current flowing during re-charge and/or for a maximum current flowing from the body  20  to the cartomizer  30  during normal operation of the e-cigarette.       

     In the event that any of the above thresholds is breached, then the re-charge (or operation of the device as appropriate) can be terminated by activating a suitable cut-off. It will be appreciated that protection for each of the above four parameters or dimensions may generally be implemented as appropriate in the over-current protection PCB  1000  and/or in the tip charge PCB  1002 , where the former relates to the re-charge or normal operation through connector  25 B, while the latter relates to re-charge through connector  900 . 
     Note that there is certain overlap or redundancy between the different dimensions of the protection. For example, the cut-off of the current supply to the battery  210  after a predetermined time period has elapsed will generally help to reduce the chance of the battery  210  becoming too hot during re-charging. However, this overlap gives greater protection, since if, for any reason, the temperature-monitoring function does not work correctly, then because current is only supplied to the battery  210  for the predetermined time period (rather than indefinitely), this may still prevent the battery from overheating. 
     The functionality shown in  FIG. 10  may be implemented using separate components. For example, the tip charge PCB  1002  may be implemented as a separate component such as a BQ24040 PCB from Texas Instruments (this can help support the use of off-the-shelf components). Alternatively, one or both of the tip charge and over-current protection PCBs  1002 ,  1000 , may be integrated as part of the microcontroller  555  (see  FIG. 6 ). A further possibility is that the tip charge and over-current protection PCBs  1002 ,  1000  are integrated together into a single device which is separate from the microcontroller  555 . 
     As described above, the e-cigarette  10  is provided with two contacts that can be used for re-charging, namely connector  900  (for charging via pack  100 ), and also connector  25 B, which can be used for charging via a (micro) USB connector when the e-cigarette  10  is in a disassembled state (the body  20  and cartomizer  30  separated). Connector  25 B can also be used for supplying power from the body to the cartomizer when the e-cigarette  10  is in an assembled state. The tip charge PCB  1002  provides protection and control in relation to charging the e-cigarette via connector  900 . The over-current protection PCB  1000  provides protection and control in relation to supplying power from the body  20  to the cartomizer  30 . 
     The over-current protection PCB  1000  may also provide protection and control in relation to charging the e-cigarette  10  from an external power supply via connector  25 B, analogous to the protection provided by tip charge PCB  1002  when re-charging via connector  900 . For example, this protection and control may involve monitoring the current and/or voltage supplied from connector  25 B, and cutting off the power supply to the battery  210  if the current or voltage exceeds a respective limit. Further, the over-current protection PCB may cut off power if the duration (time) of charging exceeds some threshold level, or if the temperature of the e-cigarette  10  is too hot or too cold. Note that over-current protection PCB  1000  may have access to temperature sensor  1006  for making this latter determination, or may be provided with its own, additional temperature sensor (not shown in  FIG. 10 ). 
       FIG. 11  schematically shows some electrical components of the recharge pack  100  in accordance with some embodiments of the disclosure. In addition to the connector  164 , battery  151  and connector  703 , as already discussed in relation to  FIGS. 8 and 9 ,  FIG. 11  also shows an over-current cut-off unit  1100 , an over-voltage cut-off unit  1102 , a multipoint control unit (MCU)  1104 , a regulator PCB  1106 , a temperature sensor  1108  and a protection circuit module (PCM)  1110 . Similar to  FIG. 10 , certain components of the pack  100  have been omitted from  FIG. 11  for the sake of clarity. 
     The pack  100  supports three main charging operations (modes). (1) When the connector  164  is electrically connected to a power source (such as a USB charging device), power flows from the power source via the connector  164  to the battery  151 . This allows the battery  151  to be charged. (2) When the connector  164  is electrically connected to a power source (such as a USB charging device), power also flows from the power source via the connectors  164  and  703  to an e-cigarette  10  (if present). This allows the battery  210  of the e-cigarette  10  to be charged (simultaneously with the pack battery  151 ). (3) When the connector  900  of an e-cigarette  10  is electrically connected to the connector  703 , but there is no external power supply for the pack at connector  164 , power flows from the battery  151  to the e-cigarette  10  via the connector  703 . This allows the battery  210  of the e-cigarette  10  to be charged. These power flows are generally controllable by one or more of the over-current cut-off  1100 , over-voltage cut-off  1102 , regulating PCB  1106 , PCM  1110  and MCU  1104 . The control of the battery charging and e-cigarette charging power flows will now be described in more detail. 
     The regulating PCB  1106  is the principal controller of power for charging the battery  151  in that it regulates the current and voltage supplied to the battery  151  during charging. In some embodiments, the regulating PCB  1106  is implemented using a MicrOne ME4057 device; however, other implementations may use different devices (or may integrate the functionality of the regulating PCB  1106  into other components). 
     The current and voltage are regulated by PCB  1106  such that they remain substantially constant at predetermined values, which are selected to provide efficient, timely and safe charging of the battery  151  and to help enhance or at least maintain the battery&#39;s long-term lifespan (the long-time lifespan being related to the total number of times a rechargeable battery can be charged and recharged before it starts permanently losing its capacity). 
     When the battery  151  is a lithium ion (Li-ion) battery, the predetermined values of the current and voltage may be about 400-500 mA and about 4.2V respectively during charging. The predetermined values may also change over the course of a single battery charge. For example, when the battery  151  is first charged, the predetermined value of the current may be lower. Then, at a later time, when the battery  151  has stored a certain amount of charge, the predetermined value of the current may be stepped up to about 400-500 mA as above. This prevents the battery  151  from being subjected to a relatively large current when it is completely discharged (or close to being completely discharged), which might otherwise cause damage to the battery  151  and reduce its long-term lifespan. Other implementations may have a different maximum current supply or voltage supply, such as somewhere in the region 250-600 mA and somewhere in the region 3-6V (respectively). 
     The regulating PCB  1106  is also connected to the temperature sensor  1108 . The temperature sensor  1108  is in thermal contact with the battery  151  so as to be responsive to the temperature of the battery  151 . As the battery  151  is charged using power supplied via the connector  164 , the battery  151  will normally heat up. However, if the battery  151  gets too hot (perhaps due to a fault in the battery  151  or because the ambient temperature is very warm), this may cause damage to the battery  151  or pack  100  or, worse, injury to the user. Also, if the battery  151  is very cold (perhaps due to the ambient temperature being very cold), then attempting to charge the battery  151  may also cause damage to the battery  151 . Thus, the regulating PCB  1106  monitors the temperature of the battery  151  using information provided by the temperature sensor  1108 . If the temperature gets too hot (that is, above a certain predetermined upper threshold) or too cold (that is, below a predetermined lower threshold), then the regulating PCB  1106  cuts off the current supply to the battery  210 . This reduces the chance of damage to the battery  151  or pack  100  and of injury to the user due the battery  151  overheating, and reduces the chance of damage to the battery  151  by charging it when it is too cold. 
     The predetermined upper temperature threshold is set such that high temperatures indicative of battery overheating result in current to the battery  151  being cut off, but normal (routine) increases in battery temperature, which do not risk damage, do not result in current to the battery  151  being cut off. Similarly, the predetermined lower temperature threshold is set such that for low temperatures, which might result in damage to the battery  151 , the current to the battery  151  is cut off. However, falls in battery temperature that remain within the specified normal operating limits do not result in current to the battery  151  being cut off. Examples of the upper and lower temperature thresholds are about 45° C. and about −5° C., respectively. However, for some batteries, the upper temperature threshold may be up to about 60° C. and the lower temperature threshold may be down to about −20° C. Typically the upper threshold is in the range 45 to 60° C., while the lower threshold is in the range 0 to −20° C. 
     In some implementations, the pack  100  may be provided with a temperature sensor that measures ambient temperature within the pack  100  (typically close to the location of any re-charging e-cigarette inside the pack  100 ). Again, this sensor may trigger a power cut-off if the temperature is found to rise above a certain threshold, such as 50° C. Note that such a temperature sensor may be provided in addition to or instead of temperature sensor  1108  as shown in  FIG. 11  (which is intended to measure primarily the temperature of the battery  151 ). 
     In addition to the current and voltage control implemented by the regulating PCB  1106 , the pack  100  is provided with further safeguards against excessive voltages or currents that are too high and which may therefore cause damage to the battery  151  or other components of the pack  100  (or injury to the user). For example, pack  100  also includes the over-current cut-off unit  1100  and the over-voltage cut-off unit  1102 . 
     The over-current cut-off unit  1100  cuts off the power supplied from the connector  164  to the other components of the pack  100  (including the regulating PCB  1106 ) when it detects that the current exceeds a predetermined threshold. Even though the current supplied to the battery  151  is regulated by the regulating PCB  1106  (as already described), the over-current cut-off unit  1100  provides an extra layer of protection to the battery  151  and other pack components. For example, the over-current cut-off unit  1100  helps to reduce the risk of damage to the components of the pack in the case that too much current is supplied via the connector  164  (this could happen, for example, if an unsuitable charging device which supplies too much current is connected to the connector  164 , or if one of the components of the pack short circuits). 
     The over-current cut-off unit  1100  may be implemented, for example, using a thermal resettable fuse, which trips out by entering a high impedance state when the current exceeds the predetermined threshold. At a later time, when the temperature cools down, the thermal resettable fuse re-enters a low impedance state again, thereby allowing current to flow again (so that use of the pack  100  may be resumed). The predetermined current threshold is set such that a high current which might cause damage is cut off, but such that variations in the current within normal and acceptable operating parameters do not produce a cut-off. For example, the predetermined current threshold may be set at about 1 amp. 
     The over-voltage cut-off unit  1102  cuts off the power supplied from the connector  164  to the other components of the pack  100  (including the regulating PCB  1106 ) if it detects that the supply voltage has exceeded a predetermined threshold. Even though the voltage supplied to the battery  151  is regulated by the regulating PCB  1106  (as described above), the over-voltage cut-off unit  1100  provides an extra layer of protection for the battery  151  and other pack components, thus reducing the risk of damage to the components in the pack  100  (or potential injury to the user) in the case that too high a voltage is supplied via the connector  164 . Such a high voltage might occur, for example, if an unsuitable charging device that supplies too high a voltage were to be connected to the connector  164 . The predetermined voltage threshold is set such that a dangerously high voltage is cut off (i.e. one that might damage the device, or possibly cause injury to a user), but variations of the voltage within the normal (non-dangerous) operating range are not cut off. For example, the predetermined voltage threshold may be set at about 6V, thereby ensuring that a 5V USB charging device will not trigger the over-voltage cut-off unit  1102 , but that higher voltages will trigger the over-voltage cut-off unit  1102 . 
     The PCM  1110 , which sits between the regulating PCB and the battery  151 , monitors the current and voltage between the battery  151  and other components of the pack (including the regulating PCB  1106 ) and trips the electrical connection between the battery  151  and the other pack components in the case that the current or voltage moves outside a predetermined current or voltage range (respectively). This monitoring is performed both for charging the battery  151  (from an external power supply via connector  164 ), and also for discharging the battery  151  (to supply power to battery  210  in the e-cigarette  10  via connector  703 , as well as to other components in the pack  100 , such as lighting  128 ). In particular, during charging or discharging of the battery  151 , if either the current or voltage exceeds (respectively) a predetermined upper threshold, then the electrical connection between the battery  151  and other pack components is tripped (cut off), i.e. the flow of power between the battery  151  and the other pack components is prevented or at least seriously impeded. This helps to reduce the risk of too much current or voltage being supplied to or from the battery  151  and the problems associated with this (such as damage to the battery  151  and/or other components, injury to the user, etc.). The threshold for the over-voltage may be set, for example, at about 4.3V, while the threshold for the over-current may be set, for example, in the range 1.5-2.5 amps, e.g. at about 1.8 amps. 
     Also, during discharging of the battery  151 , e.g. to re-charge battery  210  in e-cigarette  10 , if the voltage from the battery  151  falls below a predetermined lower threshold, then the electrical connection between the battery  151  and the other pack components, such as connector  703 , is cut off. This helps to prevent damage to the battery  151  that might otherwise occur due the continued drawing of current from the battery  151  when it has a low remaining capacity and is outputting a low voltage (this can happen with certain rechargeable batteries such as Li-ion batteries). 
     The PCM  1110  may comprise a separate PCB or may (for example) be integrated as part of the battery  151 . Due to the position of the PCM  1110  within the electrical circuit (that is, between the battery  151  and other pack components), the PCM  1110  is able to detect voltage/current abnormalities which may not be detectable by the other voltage/current-controlling pack components (such as the regulator PCB  1106 , over-current cut-off unit  1100  and over-voltage cut-off unit  1102 ). The PCM  1110  thus adds an extra layer of protection against the risk of damage to the battery  151  or any of the other pack components (or e-cigarette  10 ), and against potential injury to the user caused by abnormal current or voltage values. 
     The PCM  1110  may comprise any standard PCB suitable for detecting whether or not an applied voltage and/or current is within certain predetermined limits. Furthermore, the PCM  1110  may comprise a metal-oxide-semiconductor field-effect transistor (MOSFET) for detecting when the current exceeds the predetermined current threshold. 
     The MCU  1104  ensures that current is only supplied to the battery  151  during charging for a predetermined time period before it is cut off. This helps to ensure that the battery  151  is not subjected to overcharging, in which the battery  151  is continuously charged even though it is at full capacity (this may damage the battery  151 ). The predetermined time period is set to allow the battery to be charged to its full capacity (thereby maximizing the length of time between charges for which the user can use the pack  100 , such as to recharge the e-cigarette  10 ), but also avoiding overcharging of the battery  151 . For example, the predetermined time period may be set somewhere in the range 2 to 8 hours, such as between 4 and 6 hours. 
     The cut-off of the current supply to the battery  151  after the predetermined time period has elapsed may also help reduce the chance of the battery  151  becoming too hot or too cold. Although this is managed by the temperature-monitoring function of the regulating PCB  1106  (as already described), if, for any reason, the temperature-monitoring function does not work correctly, then, because current is only supplied to the battery  151  for the predetermined time period (rather than indefinitely), the above-discussed problems associated with continuously supplying current to the battery  151  when it is too hot may at least be alleviated. 
     The MCU  1104  also ensures that current is only supplied from the battery  151  during charging of an e-cigarette  10  via the connector  703  for a predetermined time before it is cut off. This provides an extra layer of protection to help prevent overcharging of the battery  210  of the e-cigarette  10  (in addition to the timed current cut-off function of the tip charge PCB  1002  of the e-cigarette  10  itself, as described above). For example, the predetermined time period may be set somewhere in the range 2 to 6 hours, such as between 3 and 5 hours. Note that this cut-off applies irrespective of whether the current is being supplied to the e-cigarette  10  via the external power source and connector  164  or from the pack battery  151 . 
     The overcharging of the e-cigarette battery  210  may be avoided primarily by the predetermined e-cigarette charge time of the tip charge PCB  1002 , with the predetermined e-cigarette charge time of the MCU  1104  then being set at the same or a somewhat larger value so as to act as a back-up in the event that the timer of the MCU  1104  experiences a fault and fails to cut off the current at the appropriate time. Thus, overcharging of the e-cigarette  10  can be avoided even if there is a failure in the timer function of the e-cigarette  10 . 
     Overall therefore, the pack  100  of  FIG. 11  may implement a large number of protection features such as: protection against high voltage and/or high current received from connector  164 , and/or from power being supplied from connector  164  for too long; protection against the pack  100  and/or battery  151  having too high (or too low) a temperature (this protection is relevant for all 3 of the charging modes defined above); protection against high voltage and/or high current being supplied to an e-cigarette  10  via connector  703 , and/or from power being supplied to the e-cigarette  10  via connector  703  for too long (this current/voltage and timing protection can apply irrespective of whether the e-cigarette  10  is being re-charged by an external power supply or by pack battery  151 . There may also be a cut-off implemented by PCB  1106  if the voltage of pack battery  151  exceeds a predetermined level while the pack battery  151  is re-charging (typically somewhere in the range 4.2-4.5V), or if the voltage of the pack battery  151  falls below a predetermined level while the pack battery  151  is discharging (to the e-cigarette or other components of pack). This lower voltage may be set, for example, in the range 2-3V, such as approximately 2.5V. 
     One or more of the components of  FIG. 11 , such as the regulating PCB  1106 , PCM  1110  or MCU  1104  may be integrated as part of the PCBs  160 ,  135  or  154  shown in  FIG. 8 . Alternatively, one or more of them may be separate components. In addition, the functionality may be distributed differently between the different components. Similarly, there are numerous potential variations for the connector  703  of the pack  100  and the connector  900  of the e-cigarette  10 . For example, the connectors  703 ,  900  may vary in position, size, shape, etc., so long as the connectors  703  and  900  are able to provide an electrical connection with each other to allow current to flow from the battery  151  of the pack  100  to the battery  210  of the e-cigarette  10 . 
     In light of the above-mentioned embodiments, it can be seen that the various safety components of the e-cigarette  10  (as described with reference to  FIG. 10 ) and of the pack  100  (as described with reference to  FIG. 11 ) all contribute to an overall improved control of voltage, current and temperature in the e-cigarette  10  and pack  100  during charging of the e-cigarette  10  and the pack  100 . This results in a rechargeable e-cigarette  10  and pack  100  which operate reliably and safely. 
     It will also be appreciated, however, that even if only some (rather than all) of the above-mentioned safety components of the e-cigarette  10  and/or pack  100  are implemented, then improved reliability and safety of the rechargeable e-cigarette  10  and/or pack  100  may still be enjoyed. 
     Furthermore, the approach described herein can be extended to a range of electronic vapor provision systems, such as heat-not-burn devices (which may include some plant matter or extract, for example, tobacco leaf, which is then heated or provided with steam to produce the desired vapor). One example of such an alternative form of electronic vapor provision system is described in US 2011/0226236, which discloses an inhaler containing an evaporator based on a composite planar structure that incorporates both a heating mechanism and wicking mechanism. 
     The approach described herein provides protection against malfunction by:
         a) monitoring and regulating across multiple parameters or dimensions, in particular, using time, temperature, voltage and current. Not only do these different dimensions can help to detect different fault conditions, but they also help to provide redundant (backup) protection against certain fault conditions, should one of the monitoring and regulating systems itself fail;   b) monitoring and regulating at various locations within both the e-cigarette  10  and also in the pack  100 . Monitoring and regulation at multiple locations within one device (i.e. the pack  100  or the e-cigarette  10 ), potentially for the same parameter (current, voltage, etc), again can help to detect different fault conditions, as well as helping to provide redundant (backup) protection against certain fault conditions, should one of the monitoring and regulating systems itself fail. In addition, providing corresponding monitoring and regulation functionality both in the e-cigarette  10  itself, and also in the charging pack  100 , further helps to provide some protection should a user try to use a different charging pack  100  (i.e. one without the safety components described above) for re-charging the e-cigarette  10 , or to use the charging pack  100  to re-charge a different e-cigarette (i.e. one without the safety components described above).       

     In conclusion, this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and to teach the claimed invention(s). It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilized and modifications may be made without departing from the scope of the claims. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc other than those specifically described herein. The disclosure may include one or more other inventions not presently claimed, but which may be claimed in future.