Battery Module Venting Valve for Thermal Runaway Air Blocking
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Solution Overview
Problem
Battery modules face safety risks due to thermal runaway phenomena, where a short circuit causes temperature increases, leading to potential fires and explosions, as existing structures fail to effectively block external air intake while allowing gas discharge.
Innovation Solution
A battery module design featuring a thermally expanding material at the module case's inner edge and a one-way venting valve with sealing portions that expand to seal the ventilation unit at elevated temperatures, preventing external air from entering while allowing gas to be discharged externally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ventilation unit is provided to allow air to flow smoothly for cooling, then cooling efficiency is improved, but external air can enter the module during thermal runaway causing flame spread
Solution Approach 1:
The ventilation unit incorporates a one-way venting valve that dynamically changes its state based on internal pressure conditions. During normal operation, the valve remains open to allow air flow for cooling. During thermal runaway when internal pressure increases, the valve automatically closes to prevent external air from entering and feeding the flame, thus resolving the contradiction between cooling efficiency and flame spread prevention.
Solution Approach 2:
The system utilizes pressure as a triggering parameter to change the ventilation state. When internal pressure exceeds a threshold during thermal runaway, the one-way venting valve responds to this parameter change by closing. Additionally, thermally expanding materials respond to temperature parameter changes by expanding to seal openings, thereby preventing flame spread while maintaining cooling functionality during normal operation.
2Object-affected harmful factors
If the ventilation unit is sealed to prevent air intake during thermal runaway, then flame spread is prevented, but gas discharge is blocked causing pressure buildup
Solution Approach 1:
The one-way venting valve acts as an intermediary mechanism that selectively controls gas flow direction. It allows internal gas to discharge outward during thermal runaway while preventing external air from entering. This mediator component resolves the contradiction by enabling unidirectional flow that simultaneously achieves flame spread prevention and pressure relief.
Solution Approach 2:
The ventilation unit has different functional zones with distinct properties: the one-way venting valve provides selective gas discharge functionality, while thermally expanding sealing portions provide flame blocking capability. This local differentiation of functional qualities allows the system to simultaneously achieve pressure relief and flame spread prevention without compromising either objective.
3Stress or pressure
If a one-way venting valve is used to allow gas discharge, then pressure relief is improved, but the valve structure increases device complexity
Solution Approach 1:
The one-way venting valve is designed as a passive self-regulating component that automatically responds to pressure differential without requiring external control systems, actuators, or power sources. The valve opens or closes based solely on the pressure conditions, making the system self-service and minimizing additional complexity while achieving effective pressure relief.
Solution Approach 2:
The ventilation unit incorporates thermally expanding materials that automatically expand in response to temperature increase during thermal runaway. This thermal expansion mechanism provides additional sealing functionality without requiring complex active control systems, thereby achieving flame spread prevention with minimal added structural complexity.
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 design ensures quick gas discharge and complete air blockage, preventing flame spread and reducing the risk of ignition or explosion during thermal runaway events, thereby enhancing safety.
Implementation Method 1
a case sealing portion attached onto an inner edge of the module case and a border area where an inner surface of the module case meets the module cover. The case sealing portion may be expanded at a reference temperature or above to reinforce airtightness of the module case
Implementation Method 2
The one-way venting valve may discharge a venting gas from an inside thereof to the outside when a pressure inside the module case is a reference pressure or above
Data Source
Figure 1
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AI summary
Disclosed is a battery module, which includes a cell stack having a plurality of battery cells; a module case configured to accommodate the cell stack; a pair of module covers configured to cover openings at both sides of the module case; and a ventilation unit installed through the module cover. The ventilation unit includes a one-way venting valve disposed at a center of a perforation hole formed through the module cover; a first hole sealing portion attached onto an inner wall of the perforation hole; and a second hole sealing portion attached onto an outer circumference of the one-way venting valve.