Flexible-Shell Battery Cells Without Valves for Compact Power Tools
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Solution Overview
Problem
Conventional energy supply devices for power tools often suffer from bursting due to unwanted chemical reactions and temperature fluctuations, and the presence of pressure relief valves can lead to defects, making them unsuitable for use and requiring disposal, while also limiting their compactness and cooling capacity.
Innovation Solution
The energy supply device omits pressure relief valves and incorporates cells with flexible outer shells to accommodate more chemically active material, allowing for increased energy density and improved heat dissipation, with the flexible outer shell enabling the cell to expand and contract with volume changes, enhancing thermal properties and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure relief valves are installed in cells with rigid outer walls, then cell safety is improved, but device compactness and cooling capacity deteriorate
Solution Approach 1:
The patent replaces rigid cell outer walls with flexible outer walls that can expand and contract in response to internal pressure changes. This eliminates the need for separate pressure relief valves while maintaining cell safety, thereby improving device compactness and allowing for better cooling capacity without compromising reliability
2Reliability
If pressure relief valves are installed in cells, then pressure release function is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the pressure relief valve component entirely from the cell design. The flexible outer wall inherently provides pressure relief through expansion, eliminating the need for separate valves and reducing device complexity while maintaining the pressure release function
Solution Approach 2:
The flexible outer wall serves multiple functions simultaneously: it contains the chemically active material, accommodates pressure changes through expansion, and provides inherent pressure relief without requiring additional components. This self-service approach reduces device complexity while maintaining reliability
3Ease of manufacture
If rigid outer walls are used in cells, then manufacturing simplicity is improved, but susceptibility to bursting from chemical reactions and temperature fluctuations worsens
Solution Approach 1:
The patent replaces rigid outer walls with flexible outer walls that can dynamically respond to internal pressure changes caused by unwanted chemical reactions or temperature fluctuations. This flexibility prevents bursting by allowing controlled expansion, improving reliability while maintaining ease of manufacture through the use of flexible material structures
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
This design results in a more compact, robust energy supply device with higher energy density and improved thermal properties, capable of handling high discharge currents and power-intensive applications, while reducing production costs and preventing unwanted bursting.
Implementation Method 1
the cell has a flexible outer shell, in particular in some section or sections or some region or regions
Implementation Method 2
improve the dissipation of heat from the cells to their surroundings or the cooling capacity of the cells
Data Source
AI summary
An energy supply device, in particular for a power tool, wherein the energy supply device includes at least one cell and wherein at least one cell of the energy supply device has no pressure relief valve. Moreover, the at least one cell can have a flexible outer shell, at least in some section or sections or some region or regions. The at least one cell can have an outer surface or a volume, wherein a size of the outer surface or of the volume can be changed in accordance with cell parameters. In a second aspect, the invention relates to a power tool having a proposed energy supply device.