Battery Housing Vent Cover With Thermal Screen for Emergency Gas Exhaust
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Solution Overview
Problem
Existing battery pressure compensation devices face issues with gas accumulation leading to explosion risks due to blockages or rapid melting of plastic components, which can cause fire spread and thermal runaway.
Innovation Solution
A ventilation device for battery housings featuring a permeable membrane, a perforated plastic cover with a metallic screen, and a thermal shield to prevent direct contact of incandescent particles, allowing gas to escape without obstructing the channel, even in emergency situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cover is made of plastic material with large openings for gas escape, then gas flow rate is improved, but the risk of fire spread and thermal runaway increases due to rapid melting at high temperatures
Solution Approach 1:
A metallic screen is introduced as an intermediary component between the hot gas flow and the plastic cover. The screen absorbs and dissipates thermal energy, preventing direct contact between incandescent particles and the plastic material, thereby maintaining structural integrity while allowing high gas flow rates through the perforated cover design
Solution Approach 2:
The ventilation device combines plastic material for the cover body with a metallic screen layer. This composite structure leverages the advantages of both materials: plastic provides formability and insulation, while metal provides thermal resistance and structural strength at high temperatures, resolving the contradiction between gas flow efficiency and fire safety
2Productivity
If the cover is designed to be ejected in emergency situations to increase exhaust cross-section, then gas escape capability is improved, but the risk of explosion increases due to blockage if ejection fails or is restricted
Solution Approach 1:
The cover is designed with dynamic characteristics, allowing it to be ejected from the body in emergency situations. This dynamic design enables the cover to transition from a sealed state (normal operation) to an open state (emergency venting), significantly increasing the exhaust cross-section and gas escape capability while maintaining system reliability through controlled ejection mechanisms
Solution Approach 2:
The cover is pre-positioned in a sealed configuration during normal operation to maintain pressure differential and prevent unauthorized access. In emergency situations, the pre-designed ejection mechanism activates to rapidly open the exhaust path, ensuring timely gas escape without requiring complex real-time decision-making or control systems
3Productivity
If the plastic cover is exposed to high temperatures exceeding 500°C, then gas venting capability is maintained, but the plastic melts rapidly causing blockage and increasing explosion risk
Solution Approach 1:
The metallic screen serves as a thermal intermediary that absorbs and redistributes heat away from the plastic cover material. This screen barrier prevents direct thermal coupling between the high-temperature gas flow and the plastic, maintaining the cover's mechanical properties and venting capability even when exposed to temperatures exceeding 500°C
Solution Approach 2:
The introduction of the metallic screen changes the thermal parameters of the cover system. The screen layer reduces the heat transfer coefficient to the plastic material, effectively lowering the temperature experienced by the plastic cover and preventing melting while maintaining the venting function
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 device provides effective thermal protection and prevents rapid melting of plastic components, reducing the risk of explosions and fire propagation by ensuring safe gas escape and maintaining ventilation functionality.
Implementation Method 1
a metallic-layer screen that is separate from the membrane and included in or integral with the cover, forming, in a protective zone provided in the screen, a thermal shield interposed between the channel and a portion of the obturation
Implementation Method 2
a gas-permeable membrane, carried (directly or indirectly) by the body by closing the channel, the membrane being able to constitute a filtration part capable of retaining dust and/or water
Implementation Method 3
In the event of instability (excessive internal pressure), the membrane rises to such a point that the cover of the compensation device punctures it, allowing the gas to escape at a significantly higher flow rate
Data Source
Figure 1
Figure 2A
Figure 2B~3
AI summary
The battery case ventilation device (1) includes a mounting body (2) forming or associated with an opening edge of the case, a channel (C2) in the body, a gas-permeable membrane (5) supported by the body and sealing the channel, and a cover attached to a peripheral support of the body. The channel, surrounded by this support, guides gaseous exhaust from inside the case. The cover (3) may have, opposite the channel, a piercing element (6) to puncture or rupture the membrane in case of overpressure in the channel. Orifices (O3), provided for example in the cover, allow for accelerated emergency gas exhaust from the channel when the membrane is punctured or ruptured. A metallic-coated screen (8), attached to a plastic portion (9) of the cover, forms a heat shield zone (ZP8) offset from the orifice(s) (O3).