Personal care device with a rechargeable energy source

Abstract

The present disclosure relates to a personal care device (10), the personal care device (10) comprising a rechargeable energy storage unit (110), a charging circuit (130) for receiving energy from an external energy source (300) and charging the rechargeable energy storage unit, a first charging mode in which the rechargeable energy storage unit is charged up to a preset maximum voltage value, and a user-selectable second charging mode in which the rechargeable energy storage unit is charged until the voltage in the rechargeable energy source reaches a first preset voltage value that is lower than the preset maximum voltage value. The second charging mode is selected using user-operable input elements (140, 150). The charger (300) may comprise a motion or vibration sensor (340) for detecting when the personal care device is placed on or lifted from the charger.

Description

Technical Field

[0001] The present disclosure relates to a personal care device comprising a rechargeable energy source and at least one charging mode for charging the rechargeable energy source. The present disclosure also relates to a system comprising such a personal care device and a charger.

Background Art

[0002] It is generally known to charge personal devices such as personal care devices by a general-purpose charger or a dedicated charger, specifically, by a wireless charger that provides energy for charging a rechargeable battery of the personal device in a wireless manner, for example, by inductive charging or resonant charging. The charger can utilize a standardized charging protocol such as Qi or its own charging protocol.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A general object is to provide a personal care device that enables more efficient use of the energy provided by a charger, and a system comprising the personal care device and the charger, wherein the personal care device enables more efficient use of the energy provided by the charger.

Means for Solving the Problems

[0004] According to at least one aspect, a personal care device is provided, the personal care device comprising a rechargeable energy storage unit, a charging circuit for receiving energy from an external energy source and charging the rechargeable energy storage unit, a first charging mode in which the rechargeable energy storage unit is charged up to a preset maximum voltage value, and a user-selectable second charging mode in which the rechargeable energy storage unit is charged until the voltage in the rechargeable energy source reaches a first preset voltage value lower than the preset maximum voltage value.

[0005] According to at least one aspect, a system is provided that includes a personal care device and a charger, the system comprising the personal care device described herein and a charger configured to supply energy to the personal care device.

Brief Description of the Drawings

[0006] The present disclosure will be made more apparent by a detailed description of exemplary embodiments and reference to the drawings.

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0007] In the context of this specification, "personal care" means the cultivation (or care) of the skin and its appendages (i.e., hair and nails), as well as the teeth and oral cavity (including the tongue, gums, etc.), aiming on the one hand at disease prevention and health maintenance and enhancement, and on the other hand at cosmetic treatment of the skin and its appendages and improvement of appearance. This includes the maintenance and enhancement of well-being. This includes skin care, hair care, oral care, and nail care. This further includes cosmetic operations such as jaw beard care, shaving, and hair removal. Thus, a "personal care device" means any device for performing such cultivation or cosmetic operations, for example, (cosmetic) skin treatment devices such as skin massage devices or skin brushes; wet shavers; electric shavers or trimmers; electric hair removal devices; and oral care devices such as manual or electric toothbrushes, (electric) flossers, (electric) cleaners, (electric) tongue cleaners, or (electric) gum massagers. The terms in parentheses mean that this is an optional feature. This does not exclude the possibility that the proposed personal care device may have more significant advantages in one or more of these cultivation or device areas than in one or more other areas of these areas. In this specification, an electric toothbrush is selected to represent the personal care device. Unless the details are specific to the electric toothbrush, the proposed technology can be used in any other personal care device.

[0008] The rechargeable energy storage unit shall include a secondary battery / secondary cell or a rechargeable battery such as a NiMH battery or a lithium-ion battery / Li-ion battery. In the examples provided below, the rechargeable energy storage unit is exemplified as a lithium-ion battery.

[0009] According to the present specification, the personal care device has a first charging mode in which a rechargeable energy storage unit is charged up to its maximum nominal voltage value (provided that the personal care device remains on the charger until the charging is completed). In the case of a Li-ion battery, this can generally be done, as is well known, by first applying a constant current (CC) charging stage and then applying a constant voltage (CV) charging stage, and the constant voltage (CV) charging stage typically stops when the charging current drops to a preset lower threshold value. A charge management system may be provided together with the rechargeable energy storage unit as part of the personal care device. The first charging mode may be the default charging mode used by the personal care device, particularly by the processor of the personal care device, when no alternative information is provided by the user.

[0010] According to this proposal, the personal care device also has a second charging mode that can be selected by the user. For example, the user can select the second charging mode via a user-operable input element or via a separate control device configured to wirelessly transmit a data signal to the personal care device (note that this does not exclude a wired connection). The user-operable input element can be arranged on the personal care device and / or the separate control device. The user-operable input element can be a button, a switch, a mechanical selector, a touch-sensitive switch, or a touch-sensitive display, etc. The second charging mode is characterized by causing the charging of the rechargeable energy to stop before reaching the maximum nominal speed. This is made possible by providing a first preset voltage value lower than the maximum nominal voltage value and comparing the voltage of the rechargeable energy storage unit with the first preset voltage value during the charging procedure. Next, the personal care device is configured to stop the charging of the rechargeable energy storage unit in the second charging mode when the voltage in the rechargeable energy storage unit reaches or exceeds the first preset voltage value. The personal care device may include a processor structured and configured to compare the first preset voltage value with the voltage in the rechargeable energy storage unit and interrupt or stop the charging procedure when the comparison result indicates that the voltage in the rechargeable energy storage unit has reached or exceeded the first preset voltage value. The aforementioned charging management system may be considered to be part of the processor.

[0011] To be thorough, here it is mentioned that only the second charging mode affects the personal care device. As will be explained below, a wireless charger may be used, and the charger may recognize that the energy provided for charging is not being used, in which case the wireless charger may put itself into a standby mode where no further energy is provided. In the case of wired charging, the personal care device only stops consuming the energy supplied via the wired connection. As will be explained in more detail below, the second charging mode functions to enable a more efficient charging procedure by stopping charging before reaching a charging stage where lower charging efficiency is achieved, specifically functioning for wireless charging such as resonant charging. Since the control of the second charging mode is entirely within the personal care device, there is no need for communication or data exchange between the charger and the personal care device. That being said, such communication is not excluded from still being present, for example, for purposes such as updating the firmware of the personal care device etc.

[0012] As already described, the personal care device may be an electric toothbrush. The rechargeable energy storage unit may be a rechargeable lithium-ion battery. In the case of a lithium-ion battery, the first preset voltage value of the second charging mode may be selected such that the second charging stage, for example the constant voltage mode, is avoided, i.e., the charging is stopped while the charging procedure is still in the first charging stage, for example the constant current mode. The first preset voltage value may be set to about 3.95 volts for a lithium-ion battery having a nominal maximum voltage value or a preset maximum voltage value of about 4.2 volts. The first preset voltage value may be set within the range of 3.9 volts to 4.0 volts for a lithium-ion battery having a nominal maximum voltage value or a preset maximum voltage value of 4.2 volts. This should be understood as an example for a particular battery type. For different lithium-ion batteries, different voltages may be set due to the influence of detailed chemical changes and / or aging effects, or applications. If the voltage setting should ensure, for example, that the charging is stopped in the constant current mode immediately before the start of the constant voltage stage, the voltage to be set for a particular battery can be identified by performing some tests. For example, in the case of a lithium-ion battery having a maximum nominal voltage of 3.65 volts, 4.1 volts, or 4.35 volts, the first preset voltage value may be changed accordingly over the example of about 3.95 volts, or the range may be changed over the example between 3.9 volts and 4.0 volts.

[0013] The personal care device may be structured and configured to have a third charging mode that can be selected by the user, in which the charging is stopped when the voltage in the rechargeable energy source reaches a second preset voltage value. The second preset voltage value may be higher than the first preset voltage value. In the case of a lithium-ion battery, the higher second preset voltage value may cause the charging to already be in the constant voltage mode, but the somewhat lower overall efficiency can be offset by the higher capacity to which the lithium-ion battery is charged.

[0014] In an example where a resonant charging circuit was used for wireless energy transfer between a charger and a personal care device comprising a lithium-ion battery charged in constant current and continuous constant voltage modes, with respect to charging efficiency, the charging efficiency increased from 3.0 volts to a battery voltage of about 3.9 volts, i.e., from about 33% efficiency to about 41% efficiency, and it was found that when the battery voltage exceeded about 4.0 volts, i.e., at a battery voltage of about 4.05 volts, the efficiency decreased significantly from about 40% efficiency to about 15% efficiency. In this latter regime, the energy supplied by charging is used with lower efficiency by the charging circuit within the personal care device.

[0015] The personal care device or a separate control device may have an indicator showing the estimated or pre-set efficiency of available charging modes, e.g., the first and second charging modes, so that the user can better understand the choices provided.

[0016] According to some aspects, the system described herein comprises a personal care device according to the present disclosure and a charger. The charger may be structured and configured for wireless charging of a rechargeable energy storage of the personal care device. The charger may comprise a primary side of a charging circuit, and the personal care device may comprise a secondary side of the charging circuit. The charging circuit may be structured and configured for inductive charging and / or resonant charging. The charging circuit may be able to apply a standard charging protocol such as Qi charging. The charging circuit may be implemented as described in U.S. Patent No. 10,218,212 B2, which is hereby incorporated by reference.

[0017] The charger may be connectable to a main power source. The charger may comprise a rechargeable energy storage unit, for example, an internal energy storage unit such as a rechargeable lithium-ion battery or a rechargeable NiMH battery. The charger may be structured to be used without connection to a main power source, for example, the charger may be used during travel. The internal energy storage unit of the charger may have a higher capacity than the capacity of the rechargeable energy storage unit of the personal care device, and the capacity of the internal energy storage unit of the charger may be 1.1 times higher, or 1.5 times higher, or 2 or 3 times higher, or generally higher by a wide variety of multiples, than the capacity of the rechargeable energy storage unit of the personal care device. If the user selects a second charging mode of the personal care device and less energy is lost compared to the first charging mode, the system can efficiently utilize the internal energy storage unit of the charger, which means that the energy available in the internal energy storage unit of the charger can supply more energy to the rechargeable energy source of the personal care device. In the example of an electric toothbrush, this means that the user can brush for a longer time when traveling with the available capacity of the internal energy source of the charger when the second charging mode is used compared to the first charging mode. This is because the first charging mode is less efficient, especially in the case of lithium-ion batteries.

[0018] The charger may comprise a motion or vibration sensor, or any other sensor or detector suitable for detecting when a personal care device is attached to the charger and / or when the personal care device is removed from the charger. The sensor can sense a change in the position of the charger and, instead of a motion or vibration sensor, an altitude or barometric pressure sensor or a magnetometer can be used. The charger can have a processor connected to the aforementioned sensor and can then be structured and / or configured to start supplying energy via a primary side charging circuit. The processor can then check whether the supplied energy is being utilized by a receiver, such as a device to be charged, and / or whether a resonant circuit is formed, and can then continue to supply energy wirelessly until the device to be charged, such as a personal care device, stops utilizing or consuming the supplied energy in a manner indicating charging. When the processor detects that the energy is no longer being utilized, the processor may set the charger to standby mode, and then the energy supply may be reactivated only in response to a signal from a sensor, such as a motion and vibration sensor. This does not exclude the possibility of communication, particularly wireless communication, between the charger and the personal care device, the personal care device being able to notify the charger that it requires energy, and the charger being able to notify the personal care device about the efficiency of energy use and / or the amount of energy remaining in the internal energy storage of the charger. The charger may comprise an indicator for indicating the efficiency and / or the remaining capacity of the internal energy storage.

[0019] The foregoing constant voltage charging stage is characterized by a battery voltage that is essentially constant or slowly increasing, in combination with a decreasing current. Since there are other energy-consuming components within the personal care device and losses are always present due to them, the efficiency of the energy supplied for charging decreases when the current decreases during the constant voltage stage. This means that charging a rechargeable energy storage unit in constant voltage mode tends to become less efficient as the current decreases. This is even more the case when the charging circuit between the charger and the personal care device is a resonant charging circuit, as the constant voltage stage operates the resonant charging circuit outside its most efficient resonant state or at least near the resonant state. When the charging efficiency decreases, i.e., when the battery voltage reaches or exceeds a first preset voltage value, if the personal care device stops charging, the charger may be structured and / or configured to identify that the personal care device has stopped using the supplied energy and then also stop supplying energy so that the internal energy storage of the charger can be used more efficiently.

[0020] According to at least one aspect, a personal care device is contemplated that includes a rechargeable energy storage unit, a charging circuit for receiving energy from an external energy source and charging the rechargeable energy storage unit, and a user-selectable charging mode. In the user-selectable charging mode, the rechargeable energy storage unit is charged until the voltage of the rechargeable energy source reaches a first preset voltage value that is lower than a preset maximum voltage value at which the rechargeable energy source can be charged. In particular, the rechargeable energy storage unit is a lithium-ion battery, and the first preset voltage value is selected such that charging of the lithium-ion battery is stopped before switching from a constant current charging stage to a constant voltage charging stage.

[0021] FIG. 1 is a schematic diagram of an exemplary personal care device 10 according to the present disclosure. The personal care device 10 is herein implemented as an electric toothbrush, but this is to be understood as a non-limiting example. The personal care device 10 includes a handle portion 100 and a head portion 200 that can be removably attached to the handle portion 100. The personal care device 10 includes a rechargeable energy storage unit 110 and may further include a processor 120, a secondary charging circuit 130, and / or one or more user-operable input elements 140, 150. The rechargeable energy storage unit 110 may be implemented as a lithium-ion battery. At least one of the user-operable input elements 140, 150 may be implemented as a button, or a switch, or a selector, and alternatively or additionally, at least one of the user-operable input elements 140, 150 may be implemented as a touch-sensitive element such as a touch-sensitive display. In FIG. 1, the personal care device 10 is shown as including a secondary charging circuit 130 for wireless charging of the rechargeable energy storage unit 110. This does not exclude the personal care device 10 from additionally or alternatively having a connector for direct charging.

[0022] The personal care device 10 may have a first charging mode configured such that the processor 120 charges an energy storage unit that can be recharged up to a maximum nominal voltage value or capacity, i.e., up to full charge. This may be the default or standard charging mode of the personal care device 10. Further, the personal care device 10 may have a second charging mode structured and / or configured such that the processor 120 charges an energy storage unit that can be recharged up to a first preset voltage value lower than the maximum nominal voltage at which a rechargeable energy source can be charged. The first preset voltage value may be selected such that, in the case of a lithium-ion battery implementing the rechargeable energy storage unit 100, a typical lithium-ion battery charging concept using a constant voltage stage following a constant current stage is used and the constant voltage stage is avoided, i.e., the charging is stopped at the constant current stage. This means that the processor 120 is structured and / or configured to stop charging the rechargeable energy storage unit 110 when the voltage in the rechargeable energy storage unit 110 reaches or exceeds the first preset voltage value. In some embodiments, the first preset voltage value can be set in the range between 3.9 volts and 4.0 volts, for example 3.95 volts. These settings can be used when the maximum nominal voltage value is about 4.2 volts. If the maximum nominal voltage has another value, the first preset voltage value may be changed accordingly. Also, as already mentioned, it should be understood that the first preset voltage may depend on the exact type of battery, the chemistry used, the battery life, the charging history, and / or the application in which the battery is used. Instead of stopping in constant current mode, the first preset voltage may be set such that charging stops at an earlier point in the constant voltage charging mode. As already explained, the user can select the second charging mode by using the user-operable input elements 140, 150. The selected charging mode may be indicated to the user by an indicator 160, e.g., a visual indicator such as an LED, and / or the selected charging mode may be displayed on the display 150.

[0023] FIG. 2 is a diagram of an exemplary system 1 including a charger 300 and a personal care device 10, where the personal care device 10 is shown here to be the same as the personal care device of FIG. 1, and thus the same reference numerals as in FIG. 1 are used and the description regarding FIG. 1 is incorporated by reference. The charger 300 may include an internal energy storage unit 310, a processor 320, a primary side charging circuit 330, and / or a sensor sensitive to changes in the position of the charger, for example, a motion or vibration sensor 340 that can detect when a user places the personal care device 10 on the charger 300 or lifts the personal care device 10 from the charger. Although it is shown that the charger 300 may be connectable to a main power source via a standard connector 301, it is contemplated that the charger 300 includes an internal energy source 310 having a capacity to charge the rechargeable energy storage unit 110 of the personal care device 10 at least once, and in some embodiments at least two or three times, etc. This means that the charger 300 can charge the personal care device 10 without being connected to a main power source. Here, the charger 300 may be regarded as a power bank type charger. The charger 300 may include a primary side charging circuit 330 that cooperates with the secondary side charging circuit 130 of the personal care device 10, thereby enabling wireless energy transmission from the charger 300 to the personal care device 10. The primary side charging circuit 330 and the secondary side charging circuit 130 together may form a wireless charging circuit such as an inductive charging circuit or a resonant charging circuit.

[0024] The personal care device 10 may have a second charging mode that can be selected by the user. The second charging mode stops charging the rechargeable energy source 110 of the personal care device 10 when the voltage in the rechargeable energy source reaches a first preset voltage value, which has already been described in general terms and with reference to FIG. 1. Such a second charging mode may not require communication with the charger and may depend only on measuring the voltage of the rechargeable energy storage unit of the personal care device 10. This, of course, does not exclude the personal care device 10 and the charger 300 being structured and / or configured for communication, particularly wireless communication. This also does not exclude the possibility that the charging mode generally referred to herein as the second charging mode may be the only charging mode of the personal care device. The personal care device 10 and the charger 300 may be provided by the same manufacturer and may include a mechanical lock and key fitting to ensure that only the intended personal care device can be charged on the charger 300. Instead of a mechanical lock and key fitting, the personal care device 10 and the charger 300 may be structured and / or configured to identify each other, or at least the charger 300 may be structured and / or configured to identify whether the device placed on the charger is the intended device, for example, by a specific electronic behavior of the personal care device 10. For example, when the processor 320 of the charger 300 determines that a device is placed on the charger 300, based on a signal from, for example, a motion or vibration sensor 340, the processor 320 may switch on the primary charging circuit 330 so that energy is provided to the device on the charger 300. Depending on the analysis of the electronic parameters, the processor 320 may be structured and / or configured to determine whether the device on the charger 300 is actually the intended personal care device 10 and not a different device or just a metal piece, etc. Further, the processor 320 may be structured and / or configured to determine whether the intended personal care device 10 requires charging of its rechargeable energy storage unit 110.Reference is made to U.S. Patent No. 10,218,212 B2, which is hereby incorporated by reference herein. The processor 310 may be structured and / or configured to determine when the personal care device 10 that is being energized ceases to use or consume the supplied energy, and as a result, the processor 310 may place the charger in a standby mode where no energy is supplied, and the processor 310 may monitor the motion or vibration sensor 340 again.

[0025] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A personal care device, comprising: a rechargeable energy storage unit; a charging circuit configured to receive energy from an external energy source and charge the rechargeable energy storage unit; a first charging mode in which the rechargeable energy storage unit is charged up to a preset maximum voltage value; a user-selectable second charging mode in which the rechargeable energy storage unit is charged until the voltage in the rechargeable energy source reaches a first preset voltage value lower than the preset maximum voltage value; A personal care device comprising the above.

2. The personal care device according to claim 1, wherein the personal care device is an electric toothbrush.

3. The personal care device according to claim 1 or 2, wherein the rechargeable energy source is a rechargeable lithium-ion battery.

4. The personal care device according to claim 3, wherein the charging circuit is structured and / or configured to adopt a charging concept having a first charging stage in which the lithium-ion battery is charged in a constant current mode and a second charging stage following the first charging stage in which the lithium-ion battery is charged in a constant voltage mode.

5. The personal care device according to claim 4, wherein the first preset voltage value is selected such that charging of the lithium-ion battery is stopped while the charging circuit is in the first charging stage.

6. The personal care device according to any one of claims 1 to 5, further comprising at least one user-operable input element configured to select the second charging mode.

7. The personal care device according to any one of claims 1 to 6, further comprising a user-selectable third charging mode in which the rechargeable energy storage unit is charged until the voltage in the rechargeable energy source reaches a second preset voltage value.

8. The personal care device according to any one of claims 1 to 7, wherein the first preset voltage value is in the range of 3.9 volts to 4.0 volts with respect to a maximum nominal voltage of about 4.2 volts, and in particular, the first preset voltage value is about 3.95 volts.

9. A system comprising the personal care device according to any one of claims 1 to 8 and a charger configured to supply energy to the personal care device.

10. The system according to claim 9, wherein the charger is structured and configured to supply the energy in a wireless manner.

11. The system according to claim 9 or 10, wherein the charger comprises a primary side of an inductive charging circuit, and the charging circuit of the personal care device realizes a secondary side of the inductive charging circuit.

12. The system according to any one of claims 9 to 11, wherein the charger comprises a first circuit portion of a wireless resonant charging circuit, and the charging circuit of the personal care device realizes a secondary side of the resonant charging circuit.

13. The system according to any one of claims 9 to 12, wherein the charger comprises an internal energy storage unit having a capacity higher than that of the rechargeable energy storage unit of the personal care device.

14. The system according to any one of claims 9 to 13, wherein the charger comprises a motion or vibration sensor, and the charger is structured and configured to supply energy in response to the detected motion or vibration.

15. The system according to any one of claims 9 to 14, wherein the charger monitors whether the energy supplied to the personal care device is utilized, and is structured and / or configured to switch to a standby mode when the supplied energy is not used, and in the standby mode, the charger is configured not to supply energy for charging.

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