Battery Safety Vent Assembly with Temperature-Activated Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery safety devices are inadequate in preventing thermal runaway and explosions, as they require high internal pressure to activate, have variable contact resistance, or are prone to premature activation, leading to inconsistent performance and safety concerns.
Innovation Solution
A safety vent assembly with a sealing member and an urging member that softens or melts at a threshold temperature, creating a venting path for gases to escape, reducing pressure and preventing thermal runaway, where the urging member has a fill ratio less than 100% and may be made of materials with different physical properties to ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a welded assembly is used for current connection in safety vents, then the connection strength is improved, but a very high internal pressure is required to break the welded connection
Solution Approach 1:
The patent extracts the safety function from the welded assembly by introducing a separate safety member (such as a frangible disc or weak link) that can be broken at a lower pressure threshold. This safety member is positioned in the current path between the electrode and terminal, allowing it to fail and interrupt current flow before the welded connection is compromised, thereby resolving the contradiction between connection strength and pressure threshold.
2Reliability
If a spring urged resilient conductive member is used for current connection, then the contact resistance can be maintained, but the contact resistance becomes variable and non-consistent during battery life
Solution Approach 1:
The patent segments the current connection system into a rigid conductive member and a separate safety member. The rigid conductive member provides stable, consistent electrical connection throughout battery life, while the safety member ( positioned between the electrode and terminal) provides the pressure-sensitive safety function. This segmentation eliminates the variability issue of spring-urged members while maintaining reliability.
3Strength
If a rupture disc is riveted with an annular weld plate to form current connection, then the connection is established, but a very high internal pressure is required to pop up the rupture disc
Solution Approach 1:
The patent applies local quality by creating a specific weak zone in the safety member with controlled thickness or material properties. The safety member is positioned in the current path and designed with localized reduced strength (such as a thin frangible disc or notched weak link) that allows it to fail at a predetermined lower pressure threshold, while the overall connection integrity is maintained through proper riveting and welding of the surrounding structure.
4Reliability
If safety devices are designed to prevent thermal runaway, then safety is improved, but the devices require high internal pressure to activate which delays the safety response
Solution Approach 1:
The patent implements preliminary action by pre-positioning the safety member in the current path with predetermined failure characteristics. The safety member (such as a frangible disc or weak link) is designed to fail at a specific pressure threshold that is lower than what would be required by traditional welded or riveted arrangements. This preliminary configuration ensures that when thermal runaway begins and pressure builds up, the safety device activates quickly by interrupting current flow before the pressure reaches dangerous levels.
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 internal pressure by allowing gas escape at a temperature below the venting threshold, ensuring fail-safe operations and preventing battery explosions, while maintaining consistent performance and safety.
Implementation Method 1
The urging member softens and/or melts on reaching a threshold venting temperature whereby the urging member deforms such that an axial thickness of the urging member is reduced
Implementation Method 2
the sealing member is urged by pressure inside the reaction chamber to form or open up a venting path through which gases from the reaction chamber can pass or escape
Data Source
Figure 1~3A
Figure 3B~5B
Figure 6A~7B
AI summary
A battery(10) comprises a safety vent assembly(100). The safety vent assembly(100) comprises a sealing member(104) and an urging member(106) to urge the sealing member(104) against a venting aperture(105) on a battery reaction chamber to seal the battery reaction chamber when pressure inside the battery reaction chamber is below a venting threshold pressure under normal operation conditions, wherein the sealing member(104) is operable to provide a venting path to vent gas from the battery chamber when pressure inside the battery chamber reaches the venting threshold pressure which is sufficient to overcome the urging force of the sealing member(104), and wherein the urging member(106) is to permanently deform on reaching a venting threshold temperature such that gas venting from the battery chamber will occur at a pressure below the venting threshold pressure.