Rechargeable Personal Care Charging Circuit for Partial-Charge Efficiency
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Solution Overview
Problem
Existing personal care devices, such as electric toothbrushes, face inefficiencies in energy usage during charging, particularly in wireless charging modes, where charging efficiency drops significantly beyond a certain voltage threshold, leading to less effective use of energy provided by the charger.
Innovation Solution
A personal care device with a rechargeable energy storage system that includes a user-selectable charging mode allowing the battery to charge to a predetermined voltage lower than its maximum, thereby avoiding the less efficient constant voltage charging stage, and a system comprising a charger that optimizes energy use by stopping energy provision when the device is not actively charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the rechargeable energy storage is charged to the predetermined maximum voltage value, then the total energy capacity is maximized, but the charging efficiency drops significantly beyond 3.9 Volts leading to energy loss
Solution Approach 1:
The patent applies partial action by charging the battery to a predetermined voltage (e.g., 3.9V) that is lower than the maximum possible voltage (e.g., 4.2V). This partial charging approach maintains high charging efficiency while providing sufficient energy capacity for typical usage scenarios, avoiding the inefficient constant voltage charging stage that occurs at higher voltages.
Solution Approach 2:
The patent changes the charging parameter from the traditional maximum voltage threshold to a lower predetermined voltage threshold. By modifying this critical parameter, the system operates in the more efficient constant current charging stage for longer periods, significantly improving overall charging efficiency while still meeting user energy needs.
2Quantity of substance
If the charging continues to maximum voltage, then full energy storage is achieved, but the time required for charging increases due to reduced efficiency in the constant voltage stage
Solution Approach 1:
The system performs partial charging to a predetermined voltage level that satisfies typical user needs without completing the full charging cycle to maximum voltage. This approach dramatically reduces charging time by avoiding the slow constant voltage stage, while the stored energy remains sufficient for normal usage between charges.
Solution Approach 2:
The system performs preliminary charging to a sufficient voltage level that prepares the device for typical usage scenarios without waiting for complete charging. This preliminary action provides enough energy for daily use, eliminating the need to wait for the time-consuming final stage of charging to maximum voltage.
3Ease of operation
If wireless charging is used for convenience, then the ease of operation is improved, but the charging efficiency drops significantly compared to wired charging
Solution Approach 1:
The patent combines wireless charging convenience with partial charging strategy, charging to a predetermined voltage level that maintains high efficiency even through the less efficient wireless transmission. This approach maximizes the benefit of wireless convenience while minimizing energy loss by avoiding the compounding inefficiencies of wireless charging combined with full charging to maximum voltage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances charging efficiency by maintaining higher efficiency from 3.0 to 3.9 Volts, reducing energy loss and extending usage time, especially in travel scenarios, by stopping charging before inefficiencies occur, thus making better use of the charger's energy storage.
Implementation Method 1
a rechargeable energy storage
Implementation Method 2
a charging circuit for receiving energy from an external energy source and for charging the rechargeable energy storage
Data Source
Figure 1~2
AI summary
The present disclosure is concerned with 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 storage, a first charging mode in which the rechargeable energy storage is charged to a predetermined maximum voltage value, and a user selectable second charging mode in which the rechargeable energy storage 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. The second charging mode is selected using a user-operable input element (140, 150). The charger (300) may comprise a motion or vibration sensor (340) to detect when the personal care device is placed on or lifted off the charger.