Battery unit for a portable aerosol device

Abstract

A battery unit for a portable aerosol generating device including a controller, the battery unit comprising: a lithium-ion secondary battery for powering the device, the battery comprising an outlet for venting a gas from the battery; and at least one gas sensor which is located in proximity to the outlet for detecting the vented gas and is configured to output an output signal, wherein the battery unit is configured to be deactivated if the output signal is greater than a predetermined threshold value.

Description

[0001] BATTERY UNIT FOR A PORTABLE AEROSOL DEVICE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a battery unit for a portable aerosol generating device including a controller.

[0004] BACKGROUND

[0005] A conventional portable aerosol generating device may be powered by a battery, for example a re-chargeable lithium-ion battery. The battery is typically designed to be non-replaceable and non-serviceable by the user of the device. This is advantageous, for the following reasons. The manufacturer of the device has full control over the quality, reliability, and safety of the battery used. The manufacturer does not have to ensure safe and reliable operation by implementing any sophisticated algorithms to check battery state-of-health or battery state-of- safety, thus allowing a simple device having low cost. There is also no need to design the device to support a wider range of batteries.

[0006] On the other hand, due to new sustainability targets it is expected that new regulations will be introduced within the next decade that will oblige manufacturers to sell products with replaceable batteries and a more serviceable design. At the same time, it is known that lithium-ion batteries can experience thermal runaway, a phenomenon in which the lithium-ion cell enters an uncontrollable, self-heating state. Thermal runaway can result in extremely high temperatures, violent cell venting, smoke and fire. Furthermore, new battery designs offer higher energy density with potentially higher safety related hazards. In this context, additional safety measures are desired to protect consumers, especially for HTPs (Heated Tobacco Products) that require a high amount of energy to be stored and are used close to a consumer’s mouth.

[0007] All of this creates some technical challenges, such as how to ensure battery safety, reliability and quality, and how to detect any hidden quality issues as early as possible during the service life of the device, to avoid possible consumer harm. The present invention aims to address these challenges.

[0008] SUMMARY OF INVENTION

[0009] According to an aspect of the invention, there is provided a battery unit for a portable aerosol generating device including a controller, the battery unit comprising: a lithium-ion secondary battery for powering the device, the battery comprising an outlet for venting a gas from the battery; and at least one gas sensor which is located in proximity to the outlet for detecting the vented gas and is configured to output an output signal, wherein the battery unit is configured to be deactivated if the output signal is greater than a predetermined threshold value, wherein the battery unit is configured to be deactivated both without communication with the controller and by communication with the controller upon receipt of an output by the gas sensor.

[0010] As used herein, a lithium-ion secondary battery means a rechargeable lithium-ion battery.

[0011] The inventive battery unit can be automatically deactivated, based upon detection of a dangerous level of vented battery gas, and put away in a safe place away from the user before a battery thermal runaway occurs. This is especially advantageous in the context of forthcoming repairability / replaceability regulations, which will allow consumers to replace a battery by themselves even though the replacement battery may be in a state of impairment.

[0012] The gas sensor may be a gas pressure sensor for determining gas pressure in the vicinity of the sensor. The determined pressure may be a pressure of gas which is vented from the battery, or, in the absence of vented battery gas, local air pressure. The output signal is proportional to the pressure of the detected gas, or air. A “low” output signal value is indicative of normal operation of the battery unit, i.e. when no vented battery gas is detected, or when vented battery gas is detected but the pressure of the gas is not sufficient to cause the output signal to exceed the predetermined threshold value. A “high” output signal value is indicative of abnormal operation of the battery unit, i.e. when vented battery gas is detected and the pressure of the gas is sufficient to cause the output signal to exceed the predetermined threshold value.

[0013] The battery unit may comprise: a discharging switch for performing and prohibiting discharging of the battery; a charging switch for performing and prohibiting charging of the battery; and a protection integrated circuit comprising an enable terminal, the protection integrated circuit being configured to open the discharging switch and the charging switch to deactivate the battery unit if an enable signal, which corresponds to the output signal being greater than the predetermined threshold value, is inputted into the enable terminal, wherein the battery unit is configured to input an enable signal to the enable terminal without communication with the controller if the output signal is greater than the predetermined threshold value.

[0014] Since charging and discharging of the battery may be forcibly terminated without communication with the controller, once gas leakage is detected, safety of the battery unit is ensured even if the controller freezes, or the battery unit is disconnected from the controller.

[0015] The gas sensor may be configured to output the output signal to the controller; and the enable terminal of the protection integrated circuit may be configured to receive the enable signal from the controller.

[0016] Since charging and discharging of the battery may be forcibly terminated if either controller or battery unit detects gas leakage, safety of the battery unit is further improved.

[0017] The battery unit may not have a dedicated IC (Integrated Circuit) to receive the output signal of the gas sensor and generate a disabling signal. Thus, if the protection IC receives a disabling signal from the gas sensor only directly, such architecture would not be robust against noise. The battery unit may comprise a first diode, the first diode comprising a cathode connected to the enable terminal and an anode connected to the gas sensor, wherein the enable signal from the controller is inputted between the enable terminal and the cathode of the diode.

[0018] Since the first diode isolates a signal of the controller from direct signals from the gas sensor, the protection IC will open FETs (Field-Effect Transistors) if either one of the signals shows a disabling signal. In other words, contamination of signals is avoided.

[0019] The battery unit may comprise: a plurality of the gas sensors; and an AND gate comprising: an output terminal connected to the anode of the first diode; and a plurality of input terminals respectively connected to the plurality of gas sensors.

[0020] Since a disabling signal at the battery unit is generated only when two or more of the gas sensors detect gas leakage, a false detection may be avoided.

[0021] The battery unit may comprise: a plurality of the gas sensors; and a plurality of diodes, wherein: each anode of the plurality of diodes is connected to a respective one of the plurality of the gas sensors; and each cathode of the plurality of diodes is connected to the anode of the first diode in parallel.

[0022] Since a disabling signal at the battery unit is generated when at least one of the gas sensors detects gas leakage, rapid detection may be realized.

[0023] The battery unit may comprise a user interface, wherein the battery unit is configured to provide a warning indication to the user of the device without communication with the controller, via the user interface, if the output signal is greater than the predetermined threshold value.

[0024] The battery unit may comprise a user interface switch for performing and prohibiting supplying power to the user interface, the user interface switch comprising a control terminal connected to the gas sensors. Since warning may be notified without communication with the controller, the user can recognize the situation even if the controller freezes, or the battery unit is disconnected from the controller.

[0025] The user interface may be configured to be controlled from the controller.

[0026] Since the controller may also control the user interfaces to alert the user, more controlled warning can be provided. If the control signal were directly provided from the gas sensor, the actual behavior of the user interfaces might not be so stable.

[0027] The battery unit may comprise: a second diode, the second diode comprising a cathode connected to the control terminal of the user interface switch and an anode connected to the gas sensor; and a third diode, the third diode comprising a cathode connected to the control terminal of the user interface switch and an anode connected to the controller, wherein the cathode of the second diode and the cathode of the third diode are connected in parallel.

[0028] Since the third diode isolates a signal of the controller from a direct signal from the gas sensor, the user interfaces are controlled without contamination of signals.

[0029] The battery unit may comprise: a plurality of the gas sensors; and an AND gate comprising: an output terminal connected to the anode of the second diode; and a plurality of input terminals respectively connected to the plurality of the gas sensors.

[0030] Since a warning is notified only when two or more of the gas sensors detect gas leakage, a false warning may be avoided.

[0031] The battery unit may comprise: a plurality of the gas sensors; and a plurality of diodes, wherein: each anode of plurality of diodes are respectively connected to the plurality of the gas sensors; and each cathode of plurality of diodes are connected to the anode of the second diode in parallel. Since a warning is notified only when at least one of the gas sensors detects gas leakage, a rapid warning may be realized.

[0032] According to another aspect of the invention, there is provided a portable aerosol generating device, comprising a battery unit as described herein above, the battery unit including a plurality of the gas sensors, wherein the controller is configured to deactivate the device if the output signal of one or more of the plurality of gas sensors is greater than the predetermined threshold value.

[0033] According to another aspect of the invention, there is provided a portable aerosol generating device, comprising a battery unit as described herein above, the battery unit including a plurality of the gas sensors, wherein the controller is configured to deactivate the device only if the output signal of more than one of the plurality of gas sensors is greater than the predetermined threshold value.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] Examples will now be described with reference to the accompanying figures, in which:

[0036] Figure 1 is a schematic diagram showing a cross-section of part of a lithium-ion secondary battery, which may form a part of a battery unit in accordance with the invention;

[0037] Figure 2 is a schematic diagram showing the architecture of a portable aerosol generating device, including a battery unit in accordance with the invention;

[0038] Figures 3a to 3d are schematic circuit diagrams showing an exemplary electrical circuit of a battery unit in accordance with the invention;

[0039] Figures 4a to 4d are schematic circuit diagrams showing another exemplary electrical circuit of a battery unit in accordance with the invention; and

[0040] Figure 5 shows graphs relating to the operation of a sensor, which may form a part of a battery unit in accordance with the invention. DETAILED DESCRIPTION

[0041] As used herein, IC means Integrated Circuit.

[0042] Referring to Figure 1 , a metal-can, cylindrical-cell type lithium-ion secondary battery (herein after “battery”) comprises a positive terminal (at the upper part of the drawing) and a negative terminal (not shown in the drawing), and electrodes located therebetween. A vent disc is located below the positive terminal and includes through-holes or “safety vents” for allowing gas to be vented from the inside of the battery to the surrounding atmosphere. The vent disc is secured in place by a plastic insert.

[0043] Referring next to Figure 2, the battery is installed in a replaceable battery unit in accordance with the invention. The battery unit is connected to a charger IC and a microcontroller unit (MCU) housed in a heating unit. Thus, as shown, the battery unit forms a part of a portable aerosol generating device.

[0044] Still referring to Figure 2, the battery unit comprises first and second gas sensors, each located in proximity to a respective one of the safety vents so as to be capable of detecting battery gas which may be vented from the battery. In this example, the gas sensors are gas pressure sensors, each sensor being configured to provide an output signal based on a sensed pressure of the battery gas, or of the surrounding air in the absence of battery gas, or of a mixture of battery gas and surrounding air. The number of the gas sensors is not limited to two; fewer or more gas sensors may be employed.

[0045] The battery unit further comprises a protection IC and user interfaces (U / ls). A USB-C receptacle may be provided at a bottom face of the battery unit to enable re-charging of the battery. The USB-C receptacle may be located at another face (e.g., side face) rather than the bottom face.

[0046] A thermistor is also provided for determining the temperature of the battery. The thermistor may attach on the battery or be located adjacent to the battery to precisely sense the temperature of the battery. Figure 3a shows a schematic diagram comprising a battery protection circuit board, a user interface circuit board, and a main circuit board. The battery protection circuit board and the user interface circuit board are housed in the battery unit. The main circuit board is housed in the heating unit. The battery protection circuit board includes the protection IC and the USB-C receptacle. The battery protection circuit board may optionally include a mini-breaker IC which is configured to disconnect a connection between an input terminal (labelled as “BASE” in Figure 3a) and an output terminal (labelled as “ARM” in Figure 3a) when an over-current is detected. The user interface circuit board includes warning indicators including an LED (visual warning), a vibration motor (tactile warning), and a buzzer (audible warning). The main circuit board includes the MCU and the charger IC, the charger IC being connected to the USB-C receptacle. It will be understood that the LED, the vibration motor and the buzzer are merely examples of user interfaces. Even if any one or two of those are omitted or another user interface is employed, such embodiments do not depart from the scope of the invention.

[0047] MOSFETs (Metal Oxide Semi-conductor Field-Effect Transistors) are located on the battery protection circuit board and connect the battery to the protection IC. The MOSFETs provide a discharging switch for performing and prohibiting discharging of the battery, and a charging switch for performing and prohibiting charging of the battery. In Figure 3a, the discharging switch is connected to an output terminal (labelled “DOUT”) of the protection IC, and the charging switch is connected to other output terminal (labelled “COUT”) of the protection IC. The protection IC includes a CTRL pin or enable terminal, whose input signal will determine the open / closed state of the MOSFETs. The CTRL pin works according to positive logic, so that the protection function is not activated as long as the output signal of each one of the gas sensors is “low”, i.e. no battery gas is detected. The protection IC also includes a FLAG pin to output signal indicating error signal (labelled as “DETECT_ABNORMAL”) to the MCU when any abnormal event is detected (e.g., over voltage). In this example, a first diode d1 and an AND gate are provided on the battery protection circuit board. Each one of two inputs of the AND gate is connected to a respective one of the gas sensors. The first diode d1 comprises a cathode connected to the CTRL pin and an anode connected to an output of the AND gate. Also in this example, each one of the gas sensors is connected to the MCU for sending their output signals thereto. A protection enable signal may be received by the CTRL pin when the output signal of one or more of the sensors is greater than a threshold value, and may be taken from the MCU or from the output of the AND gate. A protection enable signal from the MCU (labelled as “ENABLE_PROTECTION") may be inputted between the CTRL pin and the cathode of the first diode D1. A protection enable signal from the output of the AND gate may be provided to the CTRL pin via the first diode d1 .

[0048] In this example, a second diode d2 and a third diode d3 are provided on the battery protection circuit board. An anode of the second diode d2 is connected to one of the gas sensors and an anode of the third diode d3 is connected to the other one of the gas sensors. A cathode of the second diode d2 and a cathode of the third diode d3 are each connected to the anode of the first diode d1 in parallel. According to such configuration, output signals from the gas sensors are provided to the MCU in an exclusive manner. In otherwords, if either one of the gas sensors outputs a high level signal, high level signal is provided to the MCU. Thus the combined signal is labelled as “(EXCLUSIVELY)DETECT_BATTERY_GAS” in the Figures.

[0049] The operation of the battery unit will now be described, with reference also to Figures 3b-3d.

[0050] Figure 3b shows a normal operation condition wherein there is no detected leakage of battery gas by the gas sensors. Thus, the output signal of each one of the gas sensors is “low” and the MCU does not detect any signal indicating a gas leakage. Accordingly, the CTRL pin or enable terminal of the protection IC does not receive any protection enable signal, and the charging and discharging MOSFETs are kept in a closed state so as to enable charging and discharging of the battery. Furthermore, bipolar transistors in the user interface circuit board are kept in open state, so that the warning indicators are not activated. Of course, the bipolar transistors in the user interface circuit board may be controlled by activation signals (labelled as “ENABLE_LED”, “ENABLE_VIBRATION” and “ENABLE_BUZZER”) outputted from the MCU to indicate any notification other than a warning. Thus the enable signals are separated from the output signal from the AND gate by two diodes which each anode is connected in parallel.

[0051] Figure 3c shows an abnormal operation condition wherein a first one of the gas sensors detects a leakage of battery gas, thereby causing that gas sensor to output a “high” output signal. The second one of the gas sensors does not detect battery gas and outputs a low output signal, which is interrupted by the second diode d3 and so is not received by the MCU. The AND gate still outputs the low- level signal. The low-level signal from the second one of the gas sensors is also interrupted by diodes located on the user interface circuit board.

[0052] The high-level signal from the first one of the gas sensors is received by the MCU and is determined to exceed the pre-determined threshold value or meet the predetermined condition. Accordingly, the MCU sends a protection enable signal (labelled as “ENABLE_PROTECTION”) which is received by the CTRL pin or enable terminal. The MOSFETs are therefore turned to an open state so as to prohibit charging and discharging of the battery. The MCU also sends the activation signal to the user interface circuit board, which activates the LED, the vibration motor and the buzzer, in order to alert the user of the device to the abnormal condition.

[0053] Disabling the battery unit based on a high output signal from only one of the gas sensors, rather than both of the gas sensors, may help to shut down the battery more rapidly.

[0054] Figure 3d shows an abnormal operation condition wherein both of the gas sensors detect a leakage of battery gas, thereby causing each gas sensor to output a high output signal, which is received by the CTRL pin or enable terminal via the AND gate, without input by the MCU. Accordingly, the MOSFETs are turned off so as to prohibit charging and discharging of the battery. Thus, charging and discharging of the battery can be forcibly terminated once gas leakage is detected, even without communication with MCU. This ensures the safety of the battery unit, even if the MCU freezes or if the battery unit is disconnected from the MCU, e.g. as may be the case in Figure 3d. Yet, the high output signal is also sent to the MCU, so that the MCU can send a protection enable signal to the CTRL pin in order to shut down charging and discharging of the battery. Thus, battery charging and discharging may be terminated with, or without, use of the MCU.

[0055] The high output signal is also received by the user interface circuit board, from the gas sensors without input by the MCU, so as to activate the LED, the vibration motor and the buzzer. In this way, the user may be alerted to the abnormal condition even if the if the MCU freezes or if the battery unit is disconnected from the MCU, e.g. as may be the case in Figure 3d. Yet, the MCU may send an activation signal to the user interface circuit board to activate the LED, the vibration motor and the buzzer. Thus, the warnings may be activated with, or without, use of the MCU.

[0056] Disabling the battery unit based on a high output signal from both of the gas sensors, rather than only one of the gas sensors, may help to avoid battery shutdown as a result of a false gas detection.

[0057] Figures 4a-4d show another schematic diagram, which is generally similar to the IC shown in Figures 3a-3d except that there is no AND gate. Since the AND gate is omitted and both output of gas sensors is connected via each diode in parallel, charging and discharging of the battery can be forcibly terminated once gas leakage without communication with the MCU, if either one of the gas sensors detects a leakage of battery. The LED, the vibration motor and the buzzer are also activated without input by the MCU under such a condition.

[0058] Referring to Figure 5, when the battery starts venting the sensor will show a sharp increase of the output signal which may be used (e.g. by the MCU) to trigger deactivation of the battery, and further to activate the visual, tactile and audible warnings for the user to throw the device away or keep it in a secure place. The device may observe the temperature of the battery continuously, e.g. based on the determination of battery temperature by the thermistor, and if the cell cools down (to, say, less than 40°C) without any thermal event (including continuous negative temperature gradient deltaT I minute for 5 minutes), the device should switch off the warnings, stay disabled, and indicate a request for the user to replace the battery.

[0059] While in the above-described examples each of the gas sensors is a gas pressure sensor, in other examples a different type of gas sensor is used, such as a temperature sensor, an optical sensor, or an ultrasonic sensor. The gas sensor may be a micro-sensor. Furthermore, the battery unit may comprise any number of gas sensors, including only a single gas sensor. All such arrangements are within the scope of the claimed invention, provided that at least one gas sensor can produce an output signal and it can be determined whether the output signal exceeds a pre-determined threshold value.

[0060] It should be understood that the invention has been described in relation to its preferred embodiments and may be modified in many different ways without departing from the scope of the invention as defined by the accompanying claims.

Claims

CLAIMS1. A battery unit for a portable aerosol generating device including a controller, the battery unit comprising: a lithium-ion secondary battery for powering the device, the battery comprising an outlet for venting a gas from the battery; and at least one gas sensor which is located in proximity to the outlet for detecting the vented gas and is configured to output an output signal, wherein the battery unit is configured to be deactivated if the output signal is greater than a predetermined threshold value, wherein the battery unit is configured to be deactivated both without communication with the controller and by communication with the controller upon receipt of an output by the gas sensor.

2. A battery unit according to claim 1 , comprising: a discharging switch for performing and prohibiting discharging of the battery; a charging switch for performing and prohibiting charging of the battery; and a protection integrated circuit comprising an enable terminal, the protection integrated circuit being configured to open the discharging switch and the charging switch to deactivate the battery unit if an enable signal, which corresponds to the output signal being greater than the predetermined threshold value, is inputted into the enable terminal, wherein the battery unit is configured to input an enable signal to the enable terminal without communication with the controller if the output signal is greater than the predetermined threshold value.

3. A battery unit according to claim 2, wherein: the gas sensor is configured to output the output signal to the controller; and the enable terminal of the protection integrated circuit is configured to receive the enable signal from the controller.

4. A battery unit according to claim 3, comprising a first diode, the first diode comprising a cathode connected to the enable terminal and an anode connected to the gas sensor, wherein a further enable signal from the controller is inputted between the enable terminal and the cathode of the diode.

5. A battery unit according to claim 4, comprising: a plurality of the gas sensors; and an AND gate comprising: an output terminal connected to the anode of the first diode; and a plurality of input terminals respectively connected to the plurality of gas sensors.

6. A battery unit according to claim 4, comprising: a plurality of the gas sensors; and a plurality of diodes, wherein: each anode of the plurality of diodes is connected to a respective one of the plurality of the gas sensors; and each cathode of the plurality of diodes is connected to the anode of the first diode in parallel.

7. A battery unit according to any one of claims 2 to 6, comprising a user interface, wherein the battery unit is configured to provide a warning indication to the user of the device without communication with the controller, via the user interface, if the output signal is greater than the predetermined threshold value.

8. A battery unit according to claim 7, comprising a user interface switch for performing and prohibiting supplying power to the user interface, the user interface switch comprising a control terminal connected to the gas sensors.

9. A battery unit according to claim 8, wherein the user interface is configured to be controlled from the controller.

10. A battery unit according to claim 9, comprising:a second diode, the second diode comprising a cathode connected to the control terminal of the user interface switch and an anode connected to the gas sensor; and a third diode, the third diode comprising a cathode connected to the control terminal of the user interface switch and an anode connected to the controller, wherein the cathode of the second diode and the cathode of the third diode are connected in parallel.

11. A battery unit according to claim 10, comprising: a plurality of the gas sensors; and an AND gate comprising: an output terminal connected to the anode of the second diode; and a plurality of input terminals respectively connected to the plurality of the gas sensors.

12. A battery unit according to claim 10, comprising: a plurality of the gas sensors; and a plurality of diodes, wherein: each anode of plurality of diodes are respectively connected to the plurality of the gas sensors; and each cathode of plurality of diodes are connected to the anode of the second diode in parallel.

13. A portable aerosol generating device, comprising a battery unit according to claim 1 , the battery unit including a plurality of the gas sensors, wherein the controller is configured to deactivate the device if the output signal of one or more of the plurality of gas sensors is greater than the predetermined threshold value.

14. A portable aerosol generating device, comprising a battery unit according to claim 1 including a plurality of the gas sensors, wherein the controller is configured to deactivate the device only if the output signal of more than one of the plurality of gas sensors is greater than the predetermined threshold value.

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