Secondary Battery Safety Vent Pressure Control
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Solution Overview
Problem
Existing secondary batteries lack effective control over the operation and rupture pressure of safety vents, which is crucial for ensuring safe operation and preventing excessive pressure buildup.
Innovation Solution
The design incorporates a safety vent with a specific slope and a rupturable groove arrangement, featuring a Z-shaped cross section and a protrusion that separates from a lower plate when internal pressure exceeds a rupture pressure, allowing for controlled release of gas and minimizing the generation of broken pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional safety vent design is used, then the structure is simple, but the operation and rupture pressure cannot be effectively controlled
Solution Approach 1:
The safety vent employs a sloped surface with a specific angle range (1-5 degrees) relative to the horizontal plane, and the rupturable groove arrangement with specific geometric parameters (first groove diameter 1-4mm, second groove diameter 5-8mm) to precisely control the operation pressure and rupture pressure. This parameter optimization enables effective pressure control while maintaining a relatively simple structure.
Solution Approach 2:
The safety vent is divided into multiple functional segments: a sloped surface for pressure distribution, a first rupturable groove arrangement (inner ring groove with diameter 1-4mm) for initial rupture control, and a second rupturable groove arrangement (outer ring groove with diameter 5-8mm) for secondary rupture control. This segmentation allows independent optimization of each component's function.
2Manufacturing precision
If the safety vent has a steep slope, then the rupture pressure control is improved, but the operational stability deteriorates
Solution Approach 1:
The slope angle of the safety vent is optimized within a specific range of 1-5 degrees. This parameter optimization balances two competing requirements: a sufficient slope to enable effective rupture pressure control through pressure distribution, while maintaining a gentle enough angle to ensure operational stability and prevent premature activation.
3Manufacturing precision
If the rupturable groove diameter is small, then the precision of rupture control is improved, but the gas release efficiency deteriorates
Solution Approach 1:
The rupturable groove arrangement is segmented into two concentric ring grooves: an inner first rupturable groove with smaller diameter (1-4mm) for precise rupture control and initial pressure relief, and an outer second rupturable groove with larger diameter (5-8mm) for enhanced gas release efficiency. This segmented design allows both precision control and high productivity to be achieved simultaneously.
Solution Approach 2:
Different regions of the safety vent structure are assigned different groove characteristics: the inner region has smaller diameter grooves for precision control, while the outer region has larger diameter grooves for efficient gas release. This local differentiation of structural properties optimizes both rupture control precision and gas release efficiency in their respective zones.
Data Source
AI summary
A secondary battery, in which working pressure and rupture pressure of a safety vent are effectively controlled with respect to a slope of the safety vent and shapes of rupturable grooves. The secondary battery includes an electrode assembly arranged within a can, a cap assembly coupled to the can and including a lower portion arranged above the electrode assembly and having a through-hole arranged at a center thereof, a safety vent electrically connected to the electrode assembly through the through-hole and an insulator arranged between the safety vent and the lower portion of the cap assembly, wherein a first distance between a portion of the safety vent arranged at a region near the through-hole and the lower portion of the cap assembly is smaller than a second distance between a portion of the safety vent positioned furthest from the through-hole and the lower portion of the cap assembly.