Cordless Power Tool Protection Unit Cooling via Fan Airflow
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Solution Overview
Problem
Cordless power tools with protection units for lithium-ion batteries face heat generation issues, leading to erroneous operations and reduced unit lifespan when operating under high loads, as existing solutions do not effectively manage heat and maintain cooling performance.
Innovation Solution
A cordless power tool design incorporating a protection unit positioned within the airflow passage, utilizing a cooling fan to direct cool air both to the protection unit and the motor, ensuring efficient cooling and preventing heat influence, while maintaining the handle design's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the protection unit is provided on the body side of the power tool, then the battery pack structure is simplified, but the protection unit generates heat and causes erroneous operation under high load
Solution Approach 1:
The protection unit is extracted from the battery pack and relocated to the power tool body. This separates the protection function from the power supply unit, allowing the battery pack structure to remain simple while the protection unit can be independently cooled by the tool's cooling system.
Solution Approach 2:
The cooling fan acts as an intermediary element that provides thermal management for the protection unit. By positioning the protection unit in the cooling airflow path, the cooling fan mediates heat removal from the protection unit, preventing overheating and erroneous operation.
2Temperature
If the protection unit is positioned to be cooled by airflow, then heat generation is suppressed, but the handle design may be interrupted
Solution Approach 1:
The protection unit is positioned in a specific location within the power tool body where it can access cooling airflow without disrupting the overall handle design. The local area around the protection unit is optimized for cooling while the rest of the handle maintains its ergonomic design.
Solution Approach 2:
The protection unit is arranged in a position that utilizes three-dimensional space within the power tool body, allowing it to be cooled by airflow from multiple directions without protruding into the handle's external shape. This spatial arrangement enables thermal management while preserving the handle's integrity.
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 design effectively suppresses heat generation in the protection unit, prevents erroneous operations, and extends its lifespan by ensuring continuous cooling performance without interrupting airflow to the motor.
Implementation Method 1
a cooling fan which rotates by the rotation force of the motor; and a passage of cool air generated by the cooling fan is formed in the body casing
Implementation Method 2
the protection unit is arranged so that at least its part is located in the passage of the cool air
Data Source
AI summary
To provide a cordless power tool which can suppress heat generation of a protection unit and prevent the erroneous operation. A cordless power tool 1 includes a body casing 10; a battery 20 which is detachably attached to the body casing 10 and can supply electric power; a motor 30 which is housed in the body casing 10, and generates rotation force by the electric power of the battery 20; a cooling fan 40 which rotates by the rotation force of the motor 30; and a protection unit 50 which shuts off the power supply to the motor 30, in accordance with a detection result of the state of the battery 20, so that the battery 20 does not enter an overdischarge state or an overcurrent state. Herein, a passage of cool air generated by the cooling fan 40 is formed in the body casing 10, and the 16 protection unit 50 is arranged so that at least its part is located in the passage of the cool air.