Power Tool Regenerative Braking Profiles by Battery Pack Capacity
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Solution Overview
Problem
Existing cordless power tools do not optimize regenerative braking current based on the capacity of the battery pack, leading to potential damage and inefficiency in recharging the battery during the braking process.
Innovation Solution
A controller in the power tool determines the battery pack's ID and sets a customized braking profile, adjusting parameters such as regenerative current, duty cycle, and braking segments based on the pack's capacity to optimize the regenerative braking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking current is increased to maximize energy recovery, then energy efficiency is improved, but battery damage risk increases when battery capacity is not considered
Solution Approach 1:
The system dynamically adjusts the regenerative braking current parameter based on the battery pack's capacity (identified via pack ID). Different current thresholds are applied for different battery capacities, allowing maximum energy recovery while ensuring the current remains within safe limits for each specific battery type.
Solution Approach 2:
The controller receives feedback about the battery pack's capacity through pack ID identification and uses this information to adjust the regenerative braking current in real-time. This closed-loop approach ensures energy recovery is optimized without exceeding battery safety limits.
2Device complexity
If a fixed braking profile is used for all battery packs, then device complexity is reduced, but energy recovery efficiency deteriorates due to inability to optimize for different battery capacities
Solution Approach 1:
Instead of a single fixed braking profile, the system implements multiple braking profiles with different current thresholds corresponding to different battery capacities. The appropriate profile is selected based on pack ID, optimizing energy recovery for each battery type without requiring complex manual configuration.
Solution Approach 2:
The system automatically identifies the battery pack capacity via pack ID and self-adjusts the braking profile without user intervention. This eliminates the need for manual setup while achieving optimized energy recovery for each battery type.
3Reliability
If regenerative current threshold is lowered to ensure battery safety, then battery reliability is improved, but energy recovery efficiency decreases
Solution Approach 1:
The system sets different current thresholds for different battery packs based on their capacity. High-capacity batteries receive higher current thresholds allowing faster energy recovery, while low-capacity batteries receive lower thresholds for protection. This dynamic parameter adjustment resolves the contradiction between safety and efficiency.
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 extends battery runtime by ensuring the regenerative current is managed within the battery's capacity limits, preventing damage and maximizing energy recovery, particularly for high-capacity battery packs.
Implementation Method 1
utilizing the inductive current of the motor to bring it to a halt
Data Source
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AI summary
A power tool is provided including: a tool housing; a motor disposed within the tool housing; a battery receptacle arranged to be coupled to a battery pack having a rated capacity; a power switch circuit disposed between the battery receptacle and the motor; and a controller that controls the power switch circuit to drive the motor. The controller is configured to: determine or receive a pack ID associated with the rated capacity of the battery pack; set a braking profile for electronically braking the motor based on the pack ID; and apply an electronic brake to the motor in accordance with the set braking profile upon detection of an event associated with stoppage of the motor.