Rechargeable Battery Cap Assembly Venting Mechanism
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Solution Overview
Problem
Rechargeable batteries in small electronic devices face challenges in managing internal pressure due to heat generation, which can lead to ignition and explosion as there is limited space for vent holes, unlike those in vehicles.
Innovation Solution
A rechargeable battery design featuring a cap assembly with a vent portion welded with weaker strength to rupture at specific temperatures, or protruding portions on the cap plate to create a gap for pressure release, preventing excessive pressure buildup and potential explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vent hole is formed in the rechargeable battery case, then internal pressure can be released to prevent explosion, but the battery structure becomes more complex and space is consumed
Solution Approach 1:
The vent hole is integrated into the cap assembly structure rather than being a separate component. The cap plate itself forms the vent hole at its center, merging the sealing function of the cap with the pressure relief function, thereby reducing structural complexity while maintaining safety
Solution Approach 2:
The cap plate has different properties at different locations: the peripheral portion is welded to the case for sealing, while the center portion has a vent hole that is not welded to allow pressure release. This local differentiation enables both sealing and venting functions within a single structural element
2Volume of moving object
If the battery size is reduced for small electronic devices, then portability is improved, but the ability to form a vent hole and manage internal pressure deteriorates
Solution Approach 1:
The venting function is merged into the cap assembly, which is already a necessary component for sealing the battery. This integration eliminates the need for additional venting structures that would consume space, enabling pressure management in compact battery designs
Solution Approach 2:
The cap plate acts as a flexible barrier that can deform under pressure. When internal pressure increases, the cap plate deflects toward the electrode assembly, opening the vent hole to release pressure, then returns to its original position when pressure normalizes, providing automatic pressure management without additional components
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 solution effectively reduces the risk of explosion by allowing controlled pressure release before the battery is deformed, ensuring safe operation and preventing powerful explosions in compact battery designs.
Implementation Method 1
the vent portion has a welding strength that releases at a selected pressure
Implementation Method 2
the vent portion may be formed to be ruptured when heat of between 110° C. to 150° C. for about 6 to 7 minutes is generated inside the case
Data Source
AI summary
Disclosed is a rechargeable battery including: an electrode assembly; a case having an opening at one side and including the electrode assembly; and a cap assembly including a cap plate for closing and sealing an opening of the case, wherein the cap assembly includes a vent portion that is welded with weaker welding strength in at least some of a boundary between the cap plate and the case than the rest.