Compact 80V Battery Pack Layout for 3 kW Handheld Tools
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Solution Overview
Problem
Existing battery-powered devices face challenges in increasing power output while maintaining a compact, hand-held form factor, as adding more cells or larger components leads to increased size, weight, and potential issues like arcing, cell discharge imbalances, and compliance with shipping regulations.
Innovation Solution
A battery pack design with up to 20 lithium-based cells connected in series, a brushless direct current motor, and control electronics to manage high current and heat, along with a switch mechanism to disconnect cells for compliance, all within a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of battery cells is increased to achieve higher power output, then the power output increases, but the size and weight of the battery pack increase
Solution Approach 1:
The battery pack is divided into multiple individual cells (up to 20 lithium-based cells) connected in series, allowing the system to achieve high voltage and power output while maintaining a manageable form factor for each cell. This segmentation enables the battery pack to be constructed from standardized units that can be arranged to meet specific power requirements without proportionally increasing overall weight.
2Power
If the number of battery cells is increased to achieve higher power output, then the power output increases, but the volume of the battery pack increases
Solution Approach 1:
The battery pack is divided into multiple individual cells (up to 20 lithium-based cells) connected in series, allowing the system to achieve high voltage and power output while maintaining a manageable form factor for each cell. This segmentation enables the battery pack to be constructed from standardized units that can be arranged to meet specific power requirements without proportionally increasing overall volume.
Solution Approach 2:
The battery cells are arranged in a compact configuration where cells are nested or closely packed within the battery pack housing. This nesting approach maximizes the energy density and allows high power output to be achieved within a constrained volume suitable for hand-held devices.
3Power
If larger components are used to handle increased current and power, then the power handling capability increases, but the device size increases
Solution Approach 1:
The system operates at high voltage (up to 80 volts nominal) which allows the same power to be transmitted with lower current compared to lower voltage systems. This parameter change enables the use of smaller conductors, switches, and other electrical components while still handling the required power levels, thus maintaining a compact device form factor.
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 design achieves high power output (up to 3000 W) with sustained discharge, manages heat and current effectively, and complies with shipping regulations, ensuring safe and efficient operation in hand-held devices.
Implementation Method 1
The battery pack may include up to 20 lithium-based cells connected in series
Implementation Method 2
a brushless direct current motor
Implementation Method 3
control electronics to manage high current and heat
Implementation Method 4
a switch mechanism to disconnect cells for compliance, all within a compact form factor
Data Source
AI summary
An electrical combination, a tool system, an electric motor, a battery pack, and operating and manufacturing methods. The tool may include a tool housing, a motor supported by the tool housing, the motor having a nominal outer diameter of up to about 80 millimeters (mm), the motor being operable to output at least about 2760 watts (W), and a tool terminal electrically connected to the motor; a battery pack including a pack housing defining a volume of the battery pack, the volume being up to about 5.2×106 cubic millimeters (mm3), battery cells supported by the pack housing, the battery cells being electrically connected and having a nominal voltage of up to about 80 volts (V), and a pack terminal electrically connectable to the tool terminal to transfer current between the battery pack and the tool; and a controller operable to control the transfer of current.