Cordless Brushless Power Tool Architecture for 3-5 kW Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power tools are limited in their ability to perform heavy-duty applications due to power constraints, ergonomic disadvantages, and environmental impact, with corded tools requiring AC power sources and cordless tools having limited power and runtime.
Innovation Solution
A high-powered cordless power tool system featuring a brushless motor with a stator diameter of 60-80 mm and a stack length of 75%-125% of the outer diameter, coupled with a battery pack containing at least 15 battery cells with a nominal voltage of 3.6V and impedance of ≤13 mΩ, capable of delivering a power output of 3000-5000 W.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cordless power tools use higher voltage and capacity batteries to increase power output, then power and runtime are improved, but weight increases creating ergonomic disadvantage
Solution Approach 1:
The battery pack is divided into multiple individual battery cells (at least 15 cells) that can be arranged in series to achieve the desired voltage. This segmentation allows flexible configuration of power output while managing weight distribution, enabling the tool to achieve 3000-5000W power output without requiring a single excessively heavy battery unit.
Solution Approach 2:
The system changes the voltage parameter by configuring multiple 3.6V battery cells in series to achieve higher nominal voltages (at least 54V). This parameter change enables the motor to operate at higher power levels while using standard battery cell specifications, balancing power requirements with acceptable weight and size constraints.
2Power
If corded power tools are used for heavy duty applications, then power and runtime are improved, but portability and ease of operation deteriorate due to cord requirement
Solution Approach 1:
The system uses periodic recharging of the battery pack instead of continuous AC power connection. The high-capacity battery pack provides extended runtime periods between charges, enabling cordless operation for heavy duty applications while maintaining portability. This periodic energy supply replaces the continuous AC connection without sacrificing power availability during operational periods.
3Power
If brushless motor with optimized stator dimensions is used, then power density and efficiency are improved, but manufacturing complexity increases
Solution Approach 1:
The motor design specifies precise stator dimensional parameters (outer diameter of 60-80mm and stack length of 75%-125% of outer diameter) to optimize power density. These parameter specifications enable standardized manufacturing processes while achieving high power output. The defined parameter ranges allow for scalable production and quality control without excessive manufacturing complexity.
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
The system provides a high-powered cordless solution suitable for heavy-duty applications, eliminating the need for AC power sources and reducing environmental impact while maintaining ergonomic advantages.
Implementation Method 1
a brushless motor that is disposed in the tool housing. The brushless motor includes an output shaft operably coupled to drive a tool element
Implementation Method 2
a set of battery cells disposed in the battery pack housing, where the set of battery cells include at least 15 battery cells each having a nominal voltage of approximately 3.6V
Data Source
AI summary
A power tool system includes a power tool having a tool housing. The tool housing includes a battery pack receptacle having a set of tool terminals. A brushless motor includes an output shaft operably coupled to drive a tool element, a stator having an outer diameter of approximately 60 mm to approximately 80 mm, and a stack length of approximately 75% to approximately 125% of the outer diameter of the stator. A controller is operably connected to the set of tool terminals and to the brushless motor to control power delivery to the brushless motor. A battery pack includes a battery pack housing connectable to the battery pack receptacle on the tool housing and a set of battery cells. The set of battery cells includes at least 15 battery cells each having a nominal voltage of approximately 3.6V and an impedance of approximately ≤13 mΩ. A set of battery pack terminals is connectable to the set of tool terminals. The battery pack has a nominal voltage of at least approximately 54V and the brushless motor is operable under load to output a power of between approximately 3000 W and approximately 5000 W.