Shut-off Delay Device for Hand-held Power Tool Battery
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Solution Overview
Problem
Electric hand-held power tools with rechargeable batteries face issues of excessive battery discharge due to delayed shut-off of electrical devices, leading to potential battery damage and user-friendly operation disruptions.
Innovation Solution
An exhaustive-discharge safeguard device adjusts the shut-off delay time based on the battery's state of charge, limiting energy discharge and preventing further discharge when the charge is low, ensuring the battery is not excessively drained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If delayed shut-off is provided for electrical devices to prevent dead time and improve user-friendliness, then ease of operation is improved, but the rechargeable battery may become excessively discharged leading to damage
Solution Approach 1:
The shut-off delay time is made dynamic rather than fixed. The control unit adjusts the delay time based on the battery's state of charge, extending the delay when charge is high and reducing or eliminating it when charge is low, thus adapting the system behavior to current conditions
Solution Approach 2:
The system implements feedback by continuously monitoring the battery charge level and using this information to adjust the shut-off delay duration. The control unit receives charge level information and automatically modifies the delay parameter to prevent exhaustive discharge while maintaining operational smoothness
2Reliability
If delayed shut-off is provided for electrical devices, then control electronics have time to become fully operational and prevent dead time, but battery life is reduced due to continuous energy consumption
Solution Approach 1:
The delay duration is dynamically adjusted based on battery charge conditions. When charge is sufficient, a longer delay allows control electronics to initialize properly. When charge is low, the delay is reduced or removed to conserve energy, thus extending battery life while maintaining reliability when conditions permit
Solution Approach 2:
The system changes the delay time parameter based on the battery charge state. By modifying this temporal parameter according to energy availability, the system ensures control electronics receive adequate initialization time when energy is plentiful while preventing excessive energy consumption when energy is scarce
Data Source
AI summary
An electric hand-held power tool includes at least one electrical drive, at least one electrical device that requires electrical energy in order to operate, a shut-off delay device for the electrical drive and/or the electrical device, at least one rechargeable battery for supplying electrical energy to the drive and the electrical device and an exhaustive-discharge safeguard device. The exhaustive-discharge safeguard device specifies the delay time (Δt) of the shut-off delay device as a function of the state of charge of the rechargeable battery it has determined.