Secondary Battery Vent Portion Fracture Pattern
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Solution Overview
Problem
Miniaturization of secondary batteries increases safety concerns due to thermal runaway risks, as existing safety devices are insufficient in effectively exhausting pressurized gas and preventing explosions.
Innovation Solution
A secondary battery design featuring a vent portion with an intersecting and extending pattern on its surface, allowing for controlled gas release and minimizing the risk of uncontrolled fracturing, incorporating a Y-shaped or wishbone pattern with varying thicknesses to manage pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery is miniaturized to meet size requirements, then the device becomes more compact and portable, but safety from thermal runaway and pressure buildup becomes compromised
Solution Approach 1:
The vent portion is divided into multiple fracture lines (first, second, third fracture lines) that segment the pressure release function. These fracture lines are positioned at different locations and orientations to provide multiple independent pathways for gas escape, ensuring that if one path is blocked, others remain available. This segmentation enhances safety in miniaturized batteries where space for a single large vent is limited.
Solution Approach 2:
The fracture lines are pre-formed in the vent portion during manufacturing, creating predetermined weak points that will fracture at specific pressure thresholds. This preliminary preparation ensures that when thermal runaway occurs, the vent portion will automatically and reliably fracture to release pressure without requiring complex active control mechanisms, which would consume valuable space in miniaturized batteries.
2Ease of manufacture
If a simple vent structure is used, then manufacturing is easier and cost is reduced, but the vent cannot effectively control pressure release and prevent uncontrolled fracturing
Solution Approach 1:
Different regions of the vent portion are designed with different thicknesses and fracture characteristics. The first fracture line has a first thickness, the second fracture line has a second thickness, and the third fracture line has a third thickness. This local variation in quality allows each fracture line to respond to pressure at different thresholds, creating a staged pressure release mechanism that controls the venting process while maintaining manufacturing simplicity.
Solution Approach 2:
The invention changes the physical parameters of the vent portion by varying the thickness and orientation of different fracture lines. The first fracture line extends in a first direction with a first thickness, the second fracture line extends in a second direction with a second thickness, and the third fracture line extends in a third direction with a third thickness. These parameter variations enable controlled pressure release at different stages without complicating the overall manufacturing process.
3Ease of manufacture
If the vent portion has uniform thickness, then manufacturing is simpler, but it cannot provide staged pressure release and controlled gas exhaustion
Solution Approach 1:
The vent portion incorporates local quality variations through differently oriented and thickened fracture lines. The first fracture line is thickened in a first direction, the second fracture line is thickened in a second direction, and the third fracture line is thickened in a third direction. This local differentiation enables staged pressure release where different portions of the vent fracture at different pressure levels, providing controlled gas exhaustion while remaining compatible with standard manufacturing processes.
Data Source
AI summary
A secondary battery includes an electrode assembly having a first electrode plate, a second electrode plate and a separator interposed between the first and second electrode plates; a lower case accommodating the electrode assembly therein; and a cap assembly sealing the lower case. In the secondary battery, the lower case has the electrode assembly and a vent portion, and includes a surface facing the cap assembly. The vent portion includes an intersecting portion formed inside the surface, first and second curved portions curved to extend from the intersecting portion, and an extending portion extended in a straight line from the intersecting portion. The thickness of the intersecting portion includes the minimum thickness of the surface.