Cylindrical Battery Can with Shape Memory Alloy Rupture Ports
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Solution Overview
Problem
Conventional cylindrical lithium secondary batteries face safety issues due to gas explosions caused by high-pressure gas discharge concentrated at the top cap vent during thermal shocks, leading to potential ignition and chain explosions.
Innovation Solution
Incorporating a shape memory alloy member within the cylindrical can member that deforms and cracks at a specific temperature (130°C or higher) to create additional gas discharge ports, dispersing pressure and preventing ignition by forming a rupture portion different from the can material, thereby enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gas discharge is concentrated at the top cap vent, then the vent structure is simple, but gas explosion risk increases due to high-pressure concentrated discharge
Solution Approach 1:
The patent divides the gas discharge function into multiple locations: the top cap vent and rupture portions formed in the cylindrical can member. This segmentation disperses the concentrated high-pressure gas discharge into multiple pathways, reducing explosion risk while maintaining structural simplicity
Solution Approach 2:
The rupture portions act as intermediary discharge paths between the internal high-pressure gas and the external environment. These rupture portions, formed by materials with different thermal expansion coefficients, provide additional safe discharge channels that mediate the pressure release process
2Reliability
If a shape memory alloy member is added to create rupture portions, then safety against temperature rise is improved, but device complexity increases
Solution Approach 1:
The patent utilizes the temperature-dependent parameter change of shape memory alloy materials. When the battery temperature rises to a critical level, the shape memory alloy member undergoes a phase transformation, changing its physical state from martensite to austenite, which causes it to expand and create rupture portions in the can member for gas discharge
Solution Approach 2:
The patent employs composite material structure by combining the shape memory alloy member with the cylindrical can member. The shape memory alloy member is integrated into the can wall, creating a composite structure that maintains structural integrity during normal operation but automatically creates rupture portions when temperature triggers the phase change
3Quantity of substance
If rupture portions are formed using material different from can member, then gas discharge pathways are increased, but manufacturing complexity increases
Solution Approach 1:
The shape memory alloy member is nested within or integrated into the cylindrical can member structure. This nesting approach allows the rupture portions to be formed within the existing can wall structure, reducing manufacturing complexity compared to adding separate components
Solution Approach 2:
The shape memory alloy member is pre-installed in the can member during manufacturing in a specific phase state. The rupture portions are not created during assembly but are pre-positioned to form automatically when temperature conditions trigger the phase change, simplifying the manufacturing 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
The solution effectively reduces the risk of gas explosion and ignition by dispersing gas discharge through multiple ports, improving safety by quickly responding to temperature changes and reducing explosive power.
Implementation Method 1
a shape memory alloy member included as a part of the cylinder type can member; the shape memory alloy member is configured to deform and crack the cylinder type can member when a temperature of the shape memory alloy member reaches a predetermined temperature
Implementation Method 2
the shape memory alloy member is configured to deform and crack the cylinder type can member when a temperature of the shape memory alloy member reaches a predetermined temperature
Data Source
AI summary
A cylindrical lithium secondary battery according to the present invention can reduce gas explosion by preventing gas concentration from being concentrated only on the upper top cap vent by increasing the gas spouting passage through which the inner gas of the can is spouted by forming a rupture portion of a material different from that of the can member on a part of the cylindrical can member, and when the inside or outside of the battery is exposed to a high temperature, by making, a shape-based alloy member, which causes cracking of the can member by deformation, included a part of the can member, the gas is discharged through the can vent by the cracking of the can member to prevent explosion before the tap cap safety vent operates by the internal air pressure, and ignition that may be caused by heating by internal or external heat may be prevented.