Battery Cap Assembly With Bridge Cutoff and Pressure Venting
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Solution Overview
Problem
Secondary batteries face stability issues in abnormal environments such as overcharging, over-discharging, high temperatures, or physical impact, leading to potential safety hazards like overheating, overreaction, and fire.
Innovation Solution
A cap assembly with a current interruption device featuring a metal plate, connection, and bridges that break at a set current value, combined with a vent portion to release pressure, ensuring safety by interrupting current flow and releasing gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap assembly with current interruption device is added to enhance safety, then battery safety is improved, but device complexity increases
Solution Approach 1:
The current interruption device is integrated into the cap assembly structure, combining the cap's sealing function with the current interruption function in a single component. The bridge structure is formed as part of the cap assembly's metal plate, eliminating the need for separate current interruption components and reducing overall device complexity while maintaining enhanced safety.
Solution Approach 2:
The cap assembly serves multiple functions: it provides the sealing closure for the battery, acts as a current interruption device through its bridge structure, and includes a vent portion for pressure relief. This multi-functionality reduces the need for additional separate safety components, thereby improving battery safety without proportionally increasing device complexity.
2Reliability
If bridges with thin structure are used to enable current cutoff, then current interruption capability is improved, but mechanical strength decreases
Solution Approach 1:
The bridge structure features non-uniform thickness distribution, with thinner sections at critical locations where current interruption is needed and thicker sections in areas requiring mechanical strength. This local variation in quality allows the bridge to fulfill both functions: breaking easily under excessive current while maintaining sufficient structural integrity during normal operation and assembly.
Solution Approach 2:
The bridge's physical parameters, particularly its thickness, are optimized to specific ranges (0.1-0.3mm) that balance current interruption capability and mechanical strength. The thickness is controlled to be sufficient to maintain structural integrity during handling and assembly, yet thin enough to break reliably when excessive current flows, thus resolving the contradiction between these two requirements.
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 effectively blocks excessive current and rapidly releases gas, enhancing the safety of secondary batteries by preventing overheating and explosion.
Implementation Method 1
at least one bridge formed along a perimeter of the connection, and the at least one bridge is configured to break if a current equal to or greater than a set value flows
Implementation Method 2
The cap down plate may include a vent portion configured to break if pressure is applied above a set value
Data Source
AI summary
A cap assembly, including a current interruption device, and a cap down plate electrically connected to the current interruption device, wherein the current interruption device includes a metal plate, a connection located in a center of the metal plate, and at least one bridge along a perimeter of the connection, and the at least one bridge brakes if a current equal to or greater than a set value flows.