Battery Pack DC-DC Converter for Mains Tool Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tool batteries with secondary cell voltages below 42 volts are limited in powering mains-operated hand-held power tools, as they cannot provide the necessary intermediate circuit DC voltage required for these tools, restricting their range of use and requiring mains connection.
Innovation Solution
Integration of a battery DC-DC converter within the tool battery housing to raise the secondary cell battery voltage to a supply voltage matching the intermediate circuit DC voltage of mains-operated hand-held power tools, allowing independent operation without a mains connection, using lithium-ion cells connected in series and eliminating electrical bridge circuits for reliability and low wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tool battery with secondary cell voltage below 42 volts is used, then the battery is safe and easy to manufacture, but it cannot provide the necessary intermediate circuit DC voltage for mains-operated hand-held power tools
Solution Approach 1:
The patent applies parameter changes by transforming the voltage parameter from the battery output through a DC-DC converter. The converter changes the voltage from the battery's nominal voltage (below 42V) to a higher intermediate circuit voltage (above 42V), enabling compatibility with mains-operated tools while maintaining safe battery operation. This resolves the contradiction by decoupling the battery voltage from the tool's intermediate circuit voltage requirements.
Solution Approach 2:
The DC-DC converter acts as an intermediary device between the battery and the power tool's intermediate circuit. It mediates the voltage transformation, allowing the battery to operate at safe low voltages while providing the higher voltages needed by the tool's intermediate circuit. This intermediary resolves the voltage mismatch without requiring the battery itself to operate at high voltages.
2Adaptability or versatility
If the battery voltage is increased to match mains-operated tool requirements, then compatibility improves, but the battery complexity and safety risks increase
Solution Approach 1:
The patent segments the voltage transformation function from the battery into a separate DC-DC converter module. Instead of making the battery itself complex with series-parallel cell configurations, the solution divides the system into a simple battery pack and a dedicated converter, reducing battery complexity while achieving the required voltage output.
Solution Approach 2:
The DC-DC converter serves as an intermediary that handles the voltage transformation complexity, allowing the battery to remain simple and safe. The converter absorbs the complexity of voltage regulation and transformation, enabling battery compatibility with high-voltage tools without increasing battery structural complexity.
3Adaptability or versatility
If electrical bridge circuits are used to provide multiple voltage taps, then voltage flexibility improves, but wear and reliability decrease
Solution Approach 1:
The patent extracts the voltage transformation function from the traditional bridge circuit architecture and implements it through a modern DC-DC converter. This removes the mechanical or electrical contact components that cause wear, while maintaining the ability to provide appropriate voltages to the tool's intermediate circuit.
Solution Approach 2:
The solution replaces traditional mechanical or contact-based voltage selection systems with an electronic DC-DC converter system. This substitution eliminates mechanical wear and contact degradation, improving reliability while maintaining voltage adaptability through electronic control of the conversion process.
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 reliable and efficient power supply to mains-operated hand tools, such as rotary hammers, by increasing the battery voltage to match the tool's requirements, allowing for extended use scenarios without relying on the mains power, with a tool battery system that is easy to assemble and maintain.
Implementation Method 1
a battery DC voltage converter (DC-DC converter) integrated in the tool battery housing 290, which is electrically connected to the secondary cell battery 210 and is designed to raise the secondary cell battery voltage to a supply voltage UV
Implementation Method 2
a rectifier (AC-DC converter) that can be connected to an AC voltage network on the input side and is designed to convert a mains AC voltage into an intermediate circuit DC voltage
Implementation Method 3
a motor DC voltage converter (DC-DC converter), which is connected to the rectifier on the input side and to the electric drive motor on the output side. The DC converter is designed to convert the intermediate circuit DC voltage into a motor supply voltage
Data Source
Figure 1
AI summary
Disclosed is a rechargeable tool battery (200), in particular for energizing a hand-held power tool (100), comprising a battery housing (290) inside which a secondary cell battery (210) having a rated cell voltage (UN) is arranged; the rechargeable tool battery (200) further comprises a DC-to-DC converter which is integrated into the battery housing (290), is electrically connected to the secondary cell battery (210), and is designed to raise the rated cell voltage (UN) to a supply voltage (UV) that can be tapped at a terminal (295) of the rechargeable tool battery (200).