Personal care device with rechargeable energy source

Abstract

The present disclosure relates to a personal care device (10) having a rechargeable energy storage (110); a charging circuit (130) for receiving energy from an external energy source (300) and for charging the rechargeable energy store; a first charging mode in which the rechargeable energy store is charged to a predetermined maximum voltage value; a user-selectable second charging mode in which the rechargeable energy store is charged until the voltage at the rechargeable energy source has reached a first predetermined voltage value below the predetermined maximum voltage value. A second charging mode is selected using a user-operable input element (140, 150). The charger (300) may include a motion or vibration sensor (340) to detect 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 invention also relates to a system comprising such a personal care device and a charger. Background Art

[0002] It is generally known to charge personal appliances, such as personal care devices, with the aid of a universal charger or a proprietary charger, in particular a wireless charger that provides energy for charging a rechargeable battery of the personal appliance in a wireless manner (e.g., by inductive charging or resonant charging). The charger may utilize a standardized charging protocol (such as Qi) or a proprietary charging protocol.

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

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

[0005] According to at least one aspect, a system comprising a personal care device and a charger is provided, the system comprising a personal care device as described herein and a charger arranged for providing energy to the personal care device. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure will be further clarified by a detailed description of exemplary embodiments and with reference to the accompanying drawings. In the accompanying drawings,

[0007] Figure 1 is a schematic diagram of a personal care device according to the present disclosure; and

[0008] Figure 2 is a schematic diagram of a system including Figure 1 A personal care device and a charger cooperating with the personal care device for charging a rechargeable energy storage device of the personal care device are shown. DETAILED DESCRIPTION

[0009] In the context of this specification, "personal care" shall refer to the maintenance (or care) of the skin and its appendages (i.e., hair and nails) and teeth and oral cavity (including tongue, gums, etc.), wherein the purpose is, on the one hand, to prevent diseases and maintain and strengthen health, and on the other hand, to beautify and improve the appearance of the skin and its appendages. It should include maintaining and strengthening a sense of well-being. This includes skin care, hair care and oral care as well as nail care. This also includes combing activities such as beard care, shaving and depilation. Therefore, "personal care device" refers to any device for performing such nutrition or combing activities, such as (beauty) skin treatment devices such as skin massage devices or skin brushes; wet razors; electric razors or trimmers; electric epilators; and oral care devices, such as manual or electric toothbrushes, (electric) dental floss, (electric) irrigators, (electric) tongue cleaners, or (electric) gum massagers. The terms in brackets mean that this is an optional feature. This should not exclude that the proposed personal care device may have a more significant beneficial effect in one or more of these nutrition or device areas than in one or more of these other areas. In this specification, an electric toothbrush is selected to represent a personal care device. To the extent that these details are not specific to an electric toothbrush, the proposed technology can be used in any other personal care device.

[0010] The rechargeable energy storage device shall include a secondary battery or a rechargeable battery, such as a NiMH battery or a lithium ion battery / Li-ion battery. In the embodiments provided below, the rechargeable energy storage device is exemplified by a lithium ion battery.

[0011] According to the present description, the personal care device has a first charging mode in which the rechargeable energy storage device will be charged to its maximum nominal voltage value (under the condition that the personal care device remains on the charger until such charging is completed). In the case of lithium-ion batteries, as is generally known, this can occur by first applying a constant current (CC) charging phase and then a constant voltage (CV) charging phase, wherein the constant voltage (CV) charging phase is generally stopped once the charging current has dropped to a predetermined lower threshold. The charging management system can then be provided together with the rechargeable energy storage device as part of the personal care device. The first charging mode can be a default charging mode, which is used by the personal care device, and in particular by the processor of the personal care device, if no alternative information is provided by the user.

[0012] According to the present invention, the personal care device also includes 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, and the separate control device can be arranged to send a data signal to the personal care device in a wireless manner, even if this does not exclude a wired connection. The user-operable input element can be positioned on the personal care device and / or on a 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 in that it causes the charging of the rechargeable energy to be stopped before the maximum nominal speed is reached. This is achieved by providing a first predetermined voltage value lower than the maximum nominal voltage value and by comparing the voltage of the rechargeable energy storage device with the first predetermined voltage value during the charging process. Then, the personal care device is arranged to stop charging the rechargeable energy storage device in the second charging mode when the voltage at the rechargeable energy storage device has reached or exceeded the first predetermined voltage value. The personal care device may include a processor structured and arranged to compare a first predetermined voltage value with the voltage at the rechargeable energy storage device, and to interrupt or stop the charging procedure once the comparison indicates that the voltage at the rechargeable energy storage device has reached or exceeded the first predetermined voltage value. The charging management system as described above may be considered to be part of the processor.

[0013] For the sake of completeness, it is mentioned herein that the second charging mode only affects the personal care device. As will be discussed below, a wireless charger may be used, and the charger may recognize that the energy provided for charging is not being used and may then place itself in a standby mode in which energy is no longer provided. In the case of wired charging, the personal care device will only stop consuming energy provided via the wired connection. As will be explained in more detail below, the second charging mode is used to achieve a more efficient charging procedure, particularly for wireless charging (such as resonant charging), by stopping charging before reaching a charging stage in which a lower charging efficiency is achieved. Since the control of the second charging mode exists entirely within the personal care device, no communication or data exchange between the charger and the personal care device is required. The latter should not exclude that such communications still exist, for example for updating firmware on the personal care device, etc.

[0014] As already mentioned, the personal care device may be an electric toothbrush. The rechargeable energy storage device may be a rechargeable lithium-ion battery. In the case of a lithium-ion battery, a first predetermined voltage value of the second charging mode may be selected so that the second charging phase (e.g., constant voltage mode) is avoided, i.e., charging is stopped while the charging procedure is still in the first charging phase (e.g., in constant current mode). The first predetermined voltage value may then be set to about 3.95 volts for a lithium-ion battery having a nominal maximum voltage value or a predetermined maximum voltage value of about 4.2 volts. For a lithium-ion battery having a nominal maximum voltage value or a predetermined maximum voltage value of 4.2 volts, the first predetermined voltage value may be set to a range between 3.9 volts and 4.0 volts. This should be understood as an example for a specific battery type. For different lithium-ion batteries, different voltages may be set due to detailed chemistry and / or aging effects or applications. If the voltage setting should ensure that (for example) charging in constant current mode is stopped just before the constant voltage phase is about to begin, the voltage to be set for a specific battery may be identified by performing several tests. For lithium-ion batteries having a maximum nominal voltage of, for example, 3.65 volts or 4.1 volts or 4.35 volts, the first predetermined voltage value may be modified to an example of about 3.95 volts, respectively, or the range may be modified to an example of between 3.9 volts and 4.0 volts.

[0015] The personal care device may be structured and arranged to have a third charging mode selectable by the user, wherein in the third charging mode, charging is stopped when the voltage at the rechargeable energy source has reached a second predetermined voltage value. The second predetermined voltage value may be higher than the first predetermined voltage value. In the case of a lithium-ion battery, the higher second predetermined voltage value may result in charging already in a constant voltage mode, but the overall slightly lower efficiency may be offset by the higher capacity to which the lithium-ion battery is charged.

[0016] With respect to charging efficiency, for one example in which a resonant charging circuit is used for wireless energy transfer between a charger and a personal care device including a lithium-ion battery charged in constant current and successively constant voltage modes, it was found that the charging efficiency increased from 3.0 volts to about 3.9 volts battery voltage, i.e., from about 33% efficiency to about 41% efficiency, and that the charging efficiency dropped sharply above about 4.0 volts battery voltage, i.e., from about 40% efficiency to about 15% efficiency at about 4.05 volts battery voltage. In this latter scenario, the energy provided by the charging is used less efficiently by the charging circuit in the personal care device.

[0017] The personal care device or a separate control device may include an indicator to indicate the estimated or predetermined efficiencies of the available charging modes (eg, the first charging mode and the second charging mode) so that the user can better understand the options provided.

[0018] According to some aspects, a system as described herein includes a personal care device and a charger according to the present disclosure. The charger may be structured and arranged for wireless charging of a rechargeable energy storage device of the personal care device. The charger may include a primary side of a charging circuit, and the personal care device may include a secondary side of the charging circuit. The charging circuit may be structured and arranged for inductive charging and / or for resonant charging. The charging circuit may apply a standard charging protocol, such as Qi charging. The charging circuit may be implemented as described in US10218212 B2, which should be included herein by reference.

[0019] The charger may be connected to a mains power supply. The charger may include an internal energy storage device, such as a rechargeable energy storage device, for example, a rechargeable lithium-ion battery or a rechargeable NiMH battery, etc. The charger may then be structured to be used without a connection to the mains power supply, for example, the charger may be used during travel. The internal energy storage device of the charger may have a higher capacity than the capacity of the rechargeable energy storage device of the personal care device, wherein the capacity of the internal energy storage device of the charger may be 1.1 times higher or 1.5 times higher or twice or three times higher or generally multiple times higher than the capacity of the rechargeable energy storage device of the personal care device. Then, when the user selects a second charging mode for the personal care device, the system can effectively utilize the internal energy storage device of the charger and lose less energy compared to the first charging mode, which means that the energy available in the internal energy storage device of the charger can provide more energy for the rechargeable energy source of the personal care device. In the electric toothbrush embodiment, this means that when using the second charging mode, the user can brush longer when traveling with the available capacity of the internal energy source of the charger compared to the first charging mode, because the first charging mode is less efficient, especially in the case of lithium-ion batteries.

[0020] The charger may include a motion or vibration sensor or any other sensor or detector suitable for detecting when a personal care device is placed on the charger and / or detecting when a personal care device is removed from the charger. The sensor may be sensitive to changes in the position of the charger, and instead of a motion or vibration sensor, an altitude or air pressure sensor or a magnetometer may be used. The charger may have a processor connected to the mentioned sensor, and may then be structured and / or arranged to initiate the energy supply via the primary side charging circuit. The processor may then check whether the provided energy is utilized by a receiver (such as a device to be charged) and / or whether a resonant circuit is formed, and may then continue to provide energy wirelessly until the device to be charged (e.g., a personal care device) stops utilizing or consuming the provided energy in a manner indicating charging. Once the processor detects that the energy is no longer being utilized, the processor may set the charger to a standby mode, and the energy supply may then be activated again only in response to a signal from a sensor (e.g., a motion and vibration sensor). This should not exclude that there may be communication, in particular wireless communication, between the charger and the personal care device, and that the personal care device may inform the charger that it needs energy, and the charger may inform 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 said efficiency and / or said remaining capacity of the internal energy storage.

[0021] The aforementioned constant voltage charging phase is characterized by a combination of a substantially constant or only slowly increasing battery voltage and a reduced current. Since there are always losses caused by other energy consumers in the personal care device, the efficiency of the energy provided for charging decreases when the current in the constant voltage phase decreases. This means that charging of the rechargeable energy storage device in constant voltage mode tends to become less efficient as the current decreases more. This is even more true if the charging circuit between the charger and the personal care device is a resonant charging circuit, because the constant voltage phase forces the resonant charging circuit to operate outside of its most efficient resonance or at least close to resonance. If the personal care device stops charging when the efficiency of charging decreases, that is, when the battery voltage reaches or exceeds a first predetermined voltage value, the charger can be structured and / or arranged to identify that the personal care device has stopped using the energy provided and then also stops providing energy, so that the charger's internal energy storage can then be used more efficiently.

[0022] According to at least one aspect, a personal care device is considered, which includes: a rechargeable energy storage device; a charging circuit for receiving energy from an external energy source and for charging the rechargeable energy storage device; and a user-selectable charging mode, in which the rechargeable energy storage device is charged until the voltage at the rechargeable energy source has reached a first predetermined voltage value, which is lower than a predetermined maximum voltage value to which the rechargeable energy source can be charged, in particular when the rechargeable energy storage device is a lithium-ion battery and the first predetermined voltage value is selected so that the charging of the lithium-ion battery is stopped before switching from a constant current charging phase to a constant voltage charging phase.

[0023] Figure 1 is a schematic diagram of an example personal care device 10 according to the present disclosure. The personal care device 10 is implemented herein as an electric toothbrush, which is understood to be a non-limiting example. The personal care device 10 includes a handle portion 100 and a head portion 200 that can be detachably attached to the handle portion 100. The personal care device 10 includes a rechargeable energy storage device 110, and may also include a processor 120, a secondary side charging circuit 130 and / or one or more user-operable input elements 140, 150. The rechargeable energy storage device 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 user-operable input element 140, 150 may be implemented as a touch-sensitive element, such as a touch-sensitive display. In Figure 1 In FIG. 1 , the personal care device 10 is shown to include a secondary-side charging circuit 130 for wirelessly charging the rechargeable energy storage device 110. This does not exclude that the personal care device 10 additionally or alternatively has a connector for direct charging.

[0024] The personal care device 10 may have a first charging mode in which the processor 120 is arranged to charge the rechargeable energy storage device to a maximum nominal voltage value or capacity, i.e., to a full charge. This may be a default or standard charging mode for the personal care device 10. In addition, the personal care device 10 may have a second charging mode in which the processor 120 is structured and / or arranged to charge the rechargeable energy storage device to a first predetermined voltage value lower than the maximum nominal voltage to which the rechargeable energy source can be charged, the first predetermined voltage value being selected so that in the case of a lithium-ion battery implementing the rechargeable energy storage device 100, a typical lithium-ion battery charging concept using a constant current phase followed by a constant voltage phase is used and the constant voltage phase is avoided, i.e., charging is stopped in the constant current phase. This means that the processor 120 will then be structured and / or arranged to stop charging the rechargeable energy storage device 110 once the voltage at the rechargeable energy storage device 110 has reached or become higher than the first predetermined voltage value. In some embodiments, the first predetermined voltage value may be set to be within a range between 3.9 volts and 4.0 volts, such as 3.95 volts. These settings can be used for situations where the maximum nominal voltage value is about 4.2 volts. If the maximum nominal voltage has another value, the first predetermined voltage value can be changed respectively. It should also be understood that, as already mentioned, the first predetermined voltage may depend on the exact type of battery, the chemistry used, the age of the battery, the charging history and / or the application in which the battery is used. Instead of stopping in constant current mode, the first predetermined voltage may also be set to stop charging at an earlier point in time in constant voltage charging mode. The user may select the second charging mode by using the user-operable input elements 140, 150 as described above. The selected charging mode may be indicated to the user by means of 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.

[0025] Figure 2 is an illustration of an example system 1 including a charger 300 and a personal care device 10, which is shown here with Figure 1 The same personal care device as and therefore uses Figure 1 The same reference numerals as in the Figure 1. The charger 300 may include an internal energy storage 310, a processor 320, a primary side charging circuit 330 and / or a sensor sensitive to changes in the position of the charger, such as a motion or vibration sensor 340, which is understood to be a sensor that can detect when a user places the personal care device 10 on the charger 300 or when the personal care device 10 is lifted off the charger, etc. Although it is pointed out that the charger 300 can be connected to the mains power supply via a standard connector 301, it is expected that the charger 300 includes an internal energy source 310, which has a capacity that allows the rechargeable energy storage 110 of the personal care device 10 to be charged at least once, and in some embodiments at least twice or three times, etc. This means that the charger 300 can then enable the charging of the personal care device 10 without being connected to the mains power supply. The charger 300 can then be regarded as a charger of the mobile power supply (powerbank) type. The charger 300 may include a primary side charging circuit 330 for cooperating with the secondary side charging circuit 130 of the personal care device 10, so that energy transfer from the charger 300 to the personal care device 10 can be achieved wirelessly. The primary side charging circuit 330 and the secondary side charging circuit 130 can together form a wireless charging circuit such as an inductive charging circuit or a resonant charging circuit.

[0026] already generally and with regard to Figure 1It is described that the personal care device 10 may have a second charging mode that can be selected by the user, and when the voltage at the rechargeable energy source 110 of the personal care device 10 has reached a first predetermined voltage value, the second charging mode stops charging the rechargeable energy source. Such a second charging mode does not require any communication with the charger, but can rely solely on the measurement of the voltage of the rechargeable energy storage device of the personal care device 10. This certainly does not exclude that the personal care device 10 and the charger 300 are structured and / or arranged for communication, in particular wireless communication. This should also not exclude that the charging mode generally referred to herein as the second charging mode may be the only charging mode for 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 accessory to ensure that only the intended personal care device can be charged on the charger 300. Instead of a mechanical lock and key accessory, the personal care device 10 and the charger 300 may be structured and / or arranged to identify each other, or at least the charger 300 may be structured and / or arranged 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, for example, based on a signal from a motion or vibration sensor 340, that a device is placed on the charger 300, the processor 320 can turn on the primary side charging circuit 330 so that energy is provided to the device on the charger 300. Based on the analysis of the electronic parameters, the processor 320 can then be structured and / or arranged to determine whether the device on the charger 300 is indeed the expected personal care device 10 rather than a different device or just a piece of metal, etc., and can also be structured and / or arranged to determine whether the expected personal care device 10 needs to charge its rechargeable energy storage 110. Reference document US10218212B2, which should be included in this document by reference. The processor 310 can be structured and / or arranged to determine when the personal care device 10 being provided with energy stops using or consuming the provided energy, so that the processor 310 can then put the charger into a standby mode that does not provide energy, and the processor 310 can then monitor the motion or vibration sensor 340 again.

[0027] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​cited. Instead, unless otherwise indicated, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A personal care device, comprising: Rechargeable energy storage; a charging circuit for receiving energy from an external energy source and for charging the rechargeable energy storage device; a first charging mode, in which the rechargeable energy storage device is charged to a predetermined maximum voltage value; A user selectable second charging mode in which the rechargeable energy storage device is charged until the voltage at the rechargeable energy source has reached a first predetermined voltage value which is lower than the predetermined maximum voltage value.

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

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

4. A personal care device according to claim 3, wherein the charging circuit is structured and / or arranged to adopt a charging concept having a first charging phase and a second charging phase after the first charging phase, in which the lithium-ion battery is charged in a constant current mode, and in which the lithium-ion battery is charged in a constant voltage mode. 5 . The personal care device of claim 4 , wherein the first predetermined voltage value is selected to stop charging the lithium-ion battery when the charging circuit is in the first charging stage.

6. The personal care device according to any one of claims 1 to 5, wherein the personal care device comprises at least one user operable input element arranged for selecting the second charging mode.

7. A personal care device according to any one of claims 1 to 6, comprising a user-selectable third charging mode in which the rechargeable energy storage device is charged until the voltage at the rechargeable energy source has reached a second predetermined voltage value.

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

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

10. The system of claim 9, wherein the charger is structured and arranged to provide energy wirelessly.

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

12. The system of 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 implements 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 having a higher capacity than the capacity of the rechargeable energy storage of the personal care device.

14. A 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 arranged to provide energy in response to detected motion or vibration.

15. A system according to any one of claims 9 to 14, wherein the charger is structured and / or arranged to monitor whether energy provided to the personal care device is utilized and switch to a standby mode if the provided energy is not used, wherein in the standby mode the charger is arranged not to provide energy for charging.

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