Pouch Cell Battery Pack Layout for Compact Low-Voltage Power Tools
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Solution Overview
Problem
Existing power tools with low voltage platforms have battery packs with relatively low energy density, resulting in short battery life.
Innovation Solution
A power tool system that includes a tool body with an electric motor and a detachable battery pack. The battery pack has a nominal voltage between 3V and 9V, utilizing pouch cell units and a design that maximizes volumetric and gravimetric energy density, with a focus on compact size and high output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional battery packs with low energy density are used in low voltage power tools, then the device complexity is reduced and ease of manufacture is improved, but the battery life is shortened and energy density is low
Solution Approach 1:
The battery pack is divided into multiple individual pouch cells (typically 3-5 cells) connected in series, allowing flexible arrangement and optimization of energy density while maintaining manageable size and manufacturing complexity
Solution Approach 2:
The patent changes the voltage parameter range to 3V-9V (low voltage platform) and optimizes the energy density parameter by using pouch cell technology with specific arrangements, achieving extended battery life through parameter optimization rather than simply increasing voltage
2Volume of moving object
If battery pack size is reduced to maintain compact form factor, then ease of operation is improved, but the energy capacity is reduced
Solution Approach 1:
The patent uses flexible pouch cell technology instead of rigid cylindrical or prismatic cells, allowing the battery pack to conform to compact tool body spaces while maximizing energy capacity within the available volume
Solution Approach 2:
The pouch cells are arranged in a stacked configuration (multiple layers) rather than a single linear arrangement, utilizing three-dimensional space efficiently to increase energy capacity without increasing the overall footprint of the battery pack
3Quantity of substance
If multiple pouch cells are stacked to increase energy density, then energy density is improved, but the device complexity increases
Solution Approach 1:
Multiple pouch cells are electrically connected in series and mechanically stacked together, merging their individual energy capacities to achieve high energy density while using a unified battery pack housing and control circuitry to manage the 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 achieves extended battery life and increased power output while maintaining a compact form factor, addressing the limitations of low energy density in existing low voltage power tools.
Implementation Method 1
a cell unit disposed in the battery pack housing and electrically connected to the battery pack interface. The cell unit is a pouch cell
Data Source
AI summary
A power tool includes a tool body including an output piece, an electric motor for driving the output piece, and a body housing for accommodating the electric motor; and a battery pack detachably connected to the body housing to supply power to the electric motor. The tool body includes a body interface, the battery pack includes a battery pack interface mating with the body interface, and when the battery pack is mounted to the tool body, the body interface is connected to the battery pack interface. The battery pack further includes a battery pack housing; and a cell unit disposed in the battery pack housing and electrically connected to the battery pack interface. The cell unit is a pouch cell and the battery pack has a volumetric energy density greater than or equal to 100 mWh/cm3 and a nominal voltage less than or equal to 9 V.