Battery Vent Connecting Piece Sizing for Reliable Pressure Release
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Solution Overview
Problem
The risk of a current-collecting plate blocking an explosion-proof valve during valve opening in secondary batteries is present when the diameter of the current-collecting plate is excessively large or the diameter of the explosion-proof valve is relatively small.
Innovation Solution
A secondary battery design that limits the size relationship between the current-collecting plate, welding block, and explosion-proof valve, with a diameter ratio of 0.8 to 1.5, ensuring the connecting piece is detached during pressure release, and the welding strength is maintained to prevent interference with the valve opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diameter of the current-collecting plate is excessively large or the diameter of the explosion-proof valve is relatively small, then the electrical connection and structural integrity are maintained, but the risk of the current-collecting plate blocking the explosion-proof valve during valve opening increases
Solution Approach 1:
A first connecting piece is introduced as an intermediary component between the cover plate and the current-collecting plate. This connecting piece is welded to a region enclosed by the explosion-proof valve on the cover plate, serving as a mediator that transfers the pulling force during pressure release events, enabling the current-collecting plate to be detached without directly interfering with the explosion-proof valve operation
Solution Approach 2:
The patent specifies a diameter ratio parameter between the first connecting piece and the explosion-proof valve (0.8 φvent≤φpiece≤1.5 φvent). By controlling this dimensional parameter, the design ensures that the connecting piece can be effectively pulled out by the explosion-proof valve during pressure release while maintaining proper structural integrity and electrical connection during normal operation
2Strength
If the first connecting piece is welded to the cover plate region enclosed by the explosion-proof valve, then the electrical connection is maintained, but the welding strength may interfere with the valve opening during pressure release
Solution Approach 1:
The patent specifies a diameter ratio parameter between the first connecting piece and the explosion-proof valve (0.8 φvent≤φpiece≤1.5 φvent). By controlling this dimensional parameter, the design ensures that the connecting piece has sufficient welding strength for normal operation while being small enough to be effectively pulled out during pressure release events
Solution Approach 2:
The welding connection is designed to maintain strength during normal operation but is predetermined to fail in a controlled manner during pressure release. The welding strength is calibrated to be sufficient for electrical connection and structural integrity under normal conditions, but insufficient to prevent detachment when subjected to the pulling force generated by explosion-proof valve activation
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 design reduces the risk of the connecting piece blocking the explosion-proof valve, facilitating rapid pressure release, reducing thermal diffusion, and preventing a chain reaction in the battery pack.
Implementation Method 1
a first connecting piece arranged between the cover plate and the electrode assembly and welded to a region enclosed by the explosion-proof valve on the cover plate
Implementation Method 2
during pressure release, the first connecting piece is pulled out by the explosion-proof valve and is detached from the secondary battery
Data Source
AI summary
A secondary battery, a battery pack, and an electronic apparatus are provided. The secondary battery includes a housing having an opening, a electrode assembly accommodated in the housing, a cover plate covering the opening and having an explosion-proof valve, and a first connecting piece arranged between the cover plate and the electrode assembly and welded to a region enclosed by the explosion-proof valve on the cover plate. A diameter of the region enclosed by the explosion-proof valve is φvent, a diameter of the first connecting piece is φpiece, and 0.8 φvent≤φpiece≤1.5 φvent. When an internal pressure of the secondary battery exceeds a threshold, the explosion-proof valve opens and pulls the first connecting piece to be detached from the constraint of the housing together.