Cylindrical Li-Ion Battery Can Vent Structure for Floor Flatness
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Solution Overview
Problem
Cylindrical lithium ion secondary batteries face challenges in maintaining the flatness of the can floor, which can lead to dimensional errors and reduced safety vent effectiveness due to excess metal accumulation and potential damage during the formation of the safety vent.
Innovation Solution
A cylindrical lithium ion secondary battery design featuring a curved portion on the can floor adjacent to the safety vent, allowing excess metal to be guided away from the vent, enhancing the flatness of the can floor and reducing damage. This design includes a circular ring-shaped curved portion and safety vent with specific dimensions and a resin plate or layer for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety vent is formed on the can floor, then battery safety is improved, but excess metal accumulation causes dimensional errors and reduces manufacturing precision
Solution Approach 1:
The can floor is segmented into a flat portion and a curved portion, with the curved portion specifically designed to receive and accommodate excess metal during safety vent formation. This segmentation allows the flat portion to maintain dimensional precision while the curved portion absorbs metal accumulation, resolving the contradiction between safety vent functionality and manufacturing precision.
Solution Approach 2:
The curved portion acts as an intermediary element between the flat can floor and the safety vent. It mediates the conflict by providing a transition zone that captures excess metal, preventing it from affecting the flatness of the main can floor surface, thus maintaining both safety vent effectiveness and manufacturing precision.
2Manufacturing precision
If the can floor is made flat, then manufacturing precision is improved, but excess metal has nowhere to go and may damage the safety vent
Solution Approach 1:
The can floor is divided into distinct functional zones: a flat portion for manufacturing precision and a curved portion for metal accommodation. This segmentation ensures that the flat portion remains free of metal accumulation while the curved portion safely directs excess metal away from the safety vent, preventing damage and maintaining reliability.
Solution Approach 2:
The curved portion is extracted as a separate functional element specifically designed to remove and contain excess metal from the can floor. By taking out this metal-accommodating function from the flat floor area, the safety vent is protected from metal damage while the flat floor maintains its dimensional precision.
3Ease of operation
If the safety vent is exposed, then venting function is maintained, but the safety vent is susceptible to oxidation and damage
Solution Approach 1:
A resin plate is introduced as a protective covering over the safety vent. This thin film structure allows the safety vent to maintain its venting function while being protected from oxidation and physical damage. The resin plate acts as a barrier that preserves the safety vent's functionality while shielding it from harmful environmental factors.
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 enhanced flatness reduces dimensional errors and improves the stability of the battery during manufacturing, while the resin protection prevents oxidation and damage to the safety vent, ensuring reliable operation.
Implementation Method 1
A resin plate melted at a temperature of 100° C. to 300° C. may be attached to the curved portion to cover the safety vent.
Implementation Method 2
the resin protection prevents oxidation and damage to the safety vent, ensuring reliable operation
Data Source
AI summary
An embodiment of the present invention relates to a cylindrical lithium ion secondary battery. The technical problem to be solved is to provide a cylindrical lithium ion secondary battery which is designed such that a safety vent is formed and at the same time or afterwards excess metal can be guided to a curved portion adjacent to the safety vent, thereby enhancing the flatness of a can floor and reducing damage to the safety vent. To this end, the present invention provides a cylindrical lithium ion secondary battery comprising: a cylindrical can; an electrode assembly accommodated in the cylindrical can; and a cap assembly for sealing the cylindrical can, wherein the cylindrical can comprises a circular floor portion, a curved portion curved from the floor portion towards the electrode assembly, and a safety vent formed on the curved portion.