Battery Pack Fire Pipe Pre-Fill for Faster Thermal Runaway Response
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Solution Overview
Problem
Existing direct-spray-type fire extinguishing systems for battery packs face challenges in quickly extinguishing fires due to the time it takes for the fire extinguishing agent to reach the fire, which can lead to damage to the extinguishing pipe and uncontrollable temperature increases in battery cells.
Innovation Solution
A battery pack fire extinguishing system that includes a fire extinguishing pipe above the battery cells holding a first fire extinguishing agent at atmospheric pressure, and a supply unit connected to the pipe to supply a second fire extinguishing agent at a higher pressure. The system also features a gas intake sensor and controller to trigger the spray of the agents, with a film over the spray holes that melts to allow agent release when vent gas is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a direct-spray-type fire extinguishing system operates upon detecting fire after occurrence of thermal runaway, then the fire extinguishing agent reaches the fire through the fire extinguishing pipe, but it takes a predetermined amount of time (about 10 seconds to about 20 seconds) which makes it difficult to extinguish the fire at an early stage
Solution Approach 1:
The fire extinguishing agent is pre-filled in the fire extinguishing pipe at atmospheric pressure before any fire event occurs. This preliminary action eliminates the delay associated with agent delivery, as the agent is already in position and can be immediately discharged when thermal runaway is detected, thereby reducing the direct spray operation time while maintaining fire safety effectiveness.
2Reliability
If the fire extinguishing agent is held in the fire extinguishing pipe for extended periods, then the system is ready for immediate operation, but the agent may leak from the pipe
Solution Approach 1:
The fire extinguishing agent is held in the fire extinguishing pipe at atmospheric pressure rather than under high pressure. This parameter change in pressure conditions significantly reduces the risk of leakage during extended storage periods while maintaining the agent's readiness for immediate discharge when needed, thus preserving both reliability and preventing substance loss.
3Loss of time
If the fire extinguishing pipe is damaged by strong flame, then thermal runaway of battery cells occurs, but improving the response time is necessary to prevent this
Solution Approach 1:
The fire extinguishing agent is pre-positioned in the pipe and can be immediately discharged upon detection of thermal runaway, eliminating the 10-20 second delay. This preliminary preparation ensures that the agent reaches the fire source promptly, preventing the strong flame from damaging the pipe and avoiding subsequent thermal runaway of battery cells.
Solution Approach 2:
The system applies counter-action in advance by pre-filling the fire extinguishing pipe with the extinguishing agent at atmospheric pressure. This preliminary anti-action ensures that when thermal runaway occurs, the agent is already in position to immediately counter the fire, preventing the harmful effects of delayed response including pipe damage and thermal runaway propagation.
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
This system effectively shortens the direct spray operation time, allowing for immediate fire extinguishing and preventing thermal runaway in battery cells, while maintaining the fire extinguishing agent within the system for extended periods without leakage.
Implementation Method 1
the film may be configured to melt responsive to vent gas from the battery cells
Implementation Method 2
driving the vacuum pump to vacuum the fire extinguishing pipe
Implementation Method 3
driving the fire extinguishing agent tank to provide a fire extinguishing agent to the fire extinguishing pipe
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3~4
AI summary
A battery pack fire extinguishing system includes one or more battery cells, a fire extinguishing pipe located above the one or more battery cells and holding a first fire extinguishing agent at atmospheric pressure. A fire extinguishing agent supply unit is connected to the fire extinguishing pipe to supply a second fire extinguishing agent to the fire extinguishing pipe at a pressure higher than the atmospheric pressure.