Battery Pack Upper Cover Extinguishing Release for Thermal Diffusion
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Solution Overview
Problem
Lithium secondary batteries are prone to fires due to overcharging and overheating, leading to potential explosions, and existing solutions do not effectively prevent thermal diffusion and flame propagation.
Innovation Solution
A battery pack design incorporating a fire extinguishing material within the upper cover of the case, which includes a deformation layer made of vinyl or plastic that melts to release the extinguishing material, such as Novec, through a hole in the lower plate, to extinguish fires and prevent thermal diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium secondary batteries are used for high energy density, then energy storage capacity is improved, but fire hazard and thermal diffusion risk increase
Solution Approach 1:
The fire extinguishing material is pre-loaded in the upper cover, positioned to automatically fall into the battery module when thermal runaway occurs. This preliminary preparation ensures immediate fire suppression action without requiring external intervention or complex sensing systems.
Solution Approach 2:
The invention utilizes the upward convection of hot gases and flames during thermal runaway to trigger the release mechanism. The harmful thermal diffusion and flame propagation that carry heat upward also serve to melt the deformation layer and release the fire extinguishing material, converting the harmful thermal flow into a beneficial trigger mechanism.
2Reliability
If fire extinguishing material is added to the battery pack, then fire suppression capability is improved, but device complexity increases
Solution Approach 1:
The fire extinguishing system is merged with the existing upper cover structure of the battery pack. The upper cover simultaneously serves as a structural component and as the housing for the fire extinguishing material, eliminating the need for separate fire suppression chambers or complex release mechanisms.
Solution Approach 2:
The fire extinguishing system is designed to activate automatically through self-service mechanism. The deformation layer made of heat-sensitive material automatically melts and releases the extinguishing material when exposed to thermal runaway conditions, without requiring external sensors, controllers, or power sources.
3Extent of automation
If deformation layer is added to release extinguishing material, then automatic fire response is improved, but manufacturing complexity increases
Solution Approach 1:
The deformation layer is designed to change its physical state (from solid to liquid) in response to temperature changes during thermal runaway. This parameter change automatically triggers the release of fire extinguishing material through the pre-formed hole in the lower plate, achieving automatic response through simple phase transition physics.
Solution Approach 2:
The deformation layer is implemented as a thin film or layer of heat-sensitive material that can easily deform and rupture when exposed to high temperatures. This thin-film approach simplifies manufacturing compared to complex mechanical release mechanisms, as it can be applied as a coating or thin layer during the molding process.
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 delays flame propagation and prevents thermal diffusion by allowing the fire extinguishing material to fall and extinguish the fire, thereby enhancing safety in lithium secondary battery packs.
Implementation Method 1
the deformation layer may be made of vinyl or plastic, which is a material that melts in a flame in order to allow the fire extinguishing material to fall through the hole of the lower plate when a flame occurs
Implementation Method 2
a fire extinguishing material provided in the upper cover of the case to fall when a flame occurs
Data Source
AI summary
A battery pack includes a battery module including a plurality of battery cells; a case configured to accommodate the battery module therein, and including an upper cover; and a fire extinguishing material provided in the upper cover of the case to fall when a flame occurs.