Multi-Voltage Battery Pack for Cordless Power Tools
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Solution Overview
Problem
Conventional cordless power tool systems are limited by the inability of battery packs to provide multiple voltage outputs, restricting compatibility and efficiency across different power tools, and lack a method for uniform charging and state of charge indication for multi-voltage battery packs.
Innovation Solution
A cordless power tool system featuring a battery pack capable of supplying multiple voltages through internal connection circuits, allowing it to provide both low and high voltage outputs to different power tools, and incorporating a state of charge indicator for displaying voltage levels, along with a charging method that ensures balanced discharge and recharge of battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a battery pack is designed to provide only a single voltage output, then the design is simple and reliable, but compatibility with different power tools is limited
Solution Approach 1:
The battery pack is segmented into multiple independent battery cell groups (first group, second group, third group) that can be independently connected through switching circuits. Each group can be connected in series or parallel configurations, allowing the battery pack to output multiple voltage levels (e.g., 18V, 36V, 54V) while maintaining a relatively simple overall structure.
Solution Approach 2:
The battery pack incorporates dynamic switching capability through control circuits that can change the connection configuration of battery cell groups based on the power tool's voltage requirements. This dynamic reconfiguration allows a single battery pack design to adapt to different voltage demands without requiring multiple dedicated battery pack designs.
2Adaptability or versatility
If a battery pack provides multiple voltage outputs through multiple battery cell groups, then compatibility with different power tools is improved, but the charging process becomes complex and unbalanced
Solution Approach 1:
The charging system incorporates feedback mechanisms through control circuits that monitor the charge status of each battery cell group independently. Based on this feedback, the control circuit dynamically adjusts the charging current distribution to each group, ensuring balanced charging even when groups have different charge levels or capacities. This prevents overcharging or undercharging of individual groups.
Solution Approach 2:
The charging process dynamically changes electrical parameters (current distribution, voltage allocation) based on the real-time state of each battery cell group. The control circuit modifies charging parameters to accommodate different group states, enabling efficient and balanced charging of multiple groups simultaneously or sequentially as needed.
3Adaptability or versatility
If internal connection circuits are added to enable multiple voltage outputs, then system flexibility is enhanced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The internal connection circuits and switching components are designed with multi-functionality, serving both as voltage configuration switches and as protection circuits. The control circuit performs multiple functions including voltage detection, charging control, discharge protection, and over-current protection, reducing the need for separate dedicated components and simplifying the overall manufacturing process.
Solution Approach 2:
Multiple functional circuits (connection switching, voltage detection, charging control, protection circuits) are merged into integrated control modules that work together within the battery pack. This consolidation reduces the number of separate components needed and simplifies assembly and manufacturing processes while maintaining the ability to provide multiple voltage outputs.
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
Enables compatibility with a range of power tools by providing adjustable voltage outputs and ensures efficient charging and monitoring of battery health, enhancing system flexibility and user convenience.
Implementation Method 1
a first battery pack (existing) comprising a first plurality of battery cells providing a first operating voltage; a second battery pack (new) comprising a second plurality of battery cells capable of providing the first operating voltage and a second operating voltage
Data Source
AI summary
This application relates to a power tool system including a plurality of power tools, a plurality of battery packs and at least one battery pack charger and method for operating the power tools with the battery packs. This application also relates to a method for charging the battery packs and a method for monitoring a state of charge of the battery pack. In one implementation, the system includes an existing battery pack designed to provide (output) a relatively low voltage, an existing power tool designed to operate at the relatively low voltage, a new battery pack designed to provide (output) the relatively low voltage and a relatively high voltage, and a new power tool designed to operate at the relatively high voltage.