Battery Vent Cap Assembly with Thinner Connecting Part
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Solution Overview
Problem
Conventional battery vents require high breaking pressures and exhibit operational dispersion, making it difficult to ensure stability and safety against overcharging, which can lead to increased internal pressure, gas generation, and potential fires or explosions.
Innovation Solution
A cap assembly with a vent design featuring a body, flange, and connecting part, where the connecting part is thinner than the body and flange, allowing for a lower and more uniform breaking pressure, enhancing stability by reducing operational dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vent is used, then the vent can block current flow when internal pressure is high, but the vent requires high breaking pressure and exhibits wide operational dispersion
Solution Approach 1:
The vent structure applies local quality by creating a connecting part with different thickness than the body and flange. The connecting part has reduced thickness (0.15-0.30mm) compared to the body (0.35-0.50mm) and flange (0.30-0.45mm), making this specific location the weak point that breaks first. This localized thickness variation ensures consistent breaking pressure by concentrating stress at the connecting part, thereby improving manufacturing precision of the breaking pressure while maintaining venting reliability.
2Strength
If a conventional vent with high breaking pressure is used, then the vent structure is stronger, but the internal pressure of the battery becomes high before venting
Solution Approach 1:
The vent is segmented into three distinct parts with different thicknesses: the body, the connecting part, and the flange. This segmentation allows the connecting part to serve as a sacrificial element that breaks at lower pressure, while the body and flange remain strong. The body maintains sufficient strength (thickness 0.35-0.50mm) to provide structural support and block current flow, while the thinner connecting part (0.15-0.30mm) ensures lower breaking pressure, thus resolving the contradiction between vent strength and internal battery pressure.
3Ease of operation
If the connecting part has reduced thickness, then the breaking pressure is lower and more uniform, but the vent body and flange must maintain sufficient strength
Solution Approach 1:
The vent structure applies local quality by creating a connecting part with different thickness than the body and flange. The connecting part has reduced thickness (0.15-0.30mm) compared to the body (0.35-0.50mm) and flange (0.30-0.45mm), making this specific location the weak point that breaks first. This localized thickness variation ensures consistent breaking pressure by concentrating stress at the connecting part, thereby improving manufacturing precision of the breaking pressure while maintaining venting reliability.
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 cap assembly operates at a lower breaking pressure with reduced dispersion, improving the stability and safety of secondary batteries by effectively managing internal pressure and preventing excessive gas buildup.
Implementation Method 1
The connecting part is thinner than the body and/or the flange, enabling the vent to operate at a lower breaking pressure
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A cap assembly (70) and a secondary battery having the same, the cap assembly including a vent (73) that breaks at a relatively low, uniform, breaking pressure. The vent includes a body, a connecting part that extends from an edge of the body and is bent towards the body, and a flange that extends from the connecting part and is bent away from the body. The connecting part is thinner than the body and the flange. The secondary battery includes an electrode assembly, a can to house the electrode assembly, and the cap assembly to seal the can.