Battery Pack Coffin Venting Through Sand to Contain Thermal Runaway
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Solution Overview
Problem
Existing battery systems face challenges in managing thermal runaway, which can lead to destructive fires and explosions due to exothermic reactions, with vented gases posing risks to neighboring cells and external components, and there is a need for effective thermal isolation to prevent propagation and protect bystanders.
Innovation Solution
A battery system with a battery pack enclosed in a coffin structure, featuring a sand-filled compartment to guide and cool venting gases, using a separation element that melts at high temperatures to allow sand to extinguish fires and isolate the pack from other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery pack is enclosed in a sealed coffin structure, then thermal isolation and protection from thermal runaway propagation are improved, but the venting of hot gases and pressure relief during thermal runaway events becomes restricted
Solution Approach 1:
A sand-filled compartment is introduced as an intermediary medium between the battery pack and the external environment. The sand acts as a heat sink and flow medium that receives hot venting gases from the battery pack through a venting channel, cooling the gases through thermal conduction and convection while containing the thermal runaway effects within the coffin structure.
Solution Approach 2:
The harmful hot venting gases and thermal energy from thermal runaway are converted into a beneficial cooling process. The sand-filled compartment absorbs the thermal energy, using the heat to warm the sand while simultaneously cooling the venting gases before they exit the coffin, thus transforming the harmful thermal runaway byproduct into a controlled thermal management process.
2Object-affected harmful factors
If a sand-filled compartment is added to cool venting gases, then thermal runaway propagation prevention is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The coffin structure is segmented into distinct functional compartments: a battery pack compartment for housing the battery modules, a sand-filled compartment for thermal management and fire suppression, and a venting channel for gas flow. This segmentation allows each component to perform its specific function independently while simplifying the overall design and manufacturing process.
Solution Approach 2:
The sand-filled compartment utilizes the porous nature of sand as a material that can absorb and distribute thermal energy throughout its volume. The granular structure of sand provides high surface area for heat transfer, enabling efficient cooling of venting gases while maintaining a relatively simple compartment design without requiring complex heat exchange surfaces.
3Strength
If the coffin structure is made robust to contain thermal runaway, then safety and protection of bystanders are improved, but weight and manufacturing cost increase
Solution Approach 1:
The coffin structure utilizes thin-walled enclosures for the battery pack compartment and sand-filled compartment, relying on the contained sand and controlled venting channels rather than thick protective walls to manage thermal runaway. This approach reduces the overall weight and material requirements while maintaining safety through active thermal management rather than passive structural protection.
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 system effectively cools and isolates venting gases, preventing thermal propagation and external damage, prolonging battery life and protecting bystanders by reducing gas temperature and suppressing fires.
Implementation Method 1
The sand-filled compartment forms a venting channel filled with sand and is configured to guide venting gases exhausted from the pack venting element through the sand to a venting outlet in the coffin
Implementation Method 2
The system effectively cools and isolates venting gases, preventing thermal propagation and external damage
Implementation Method 3
using a separation element that melts at high temperatures to allow sand to extinguish fires and isolate the pack from other components
Data Source
AI summary
A battery system includes: a coffin having a battery compartment and a sand-filled compartment separated from the battery compartment; and a battery pack accommodated within the battery compartment. The battery pack includes a pack housing, a plurality of battery cells accommodated within the pack housing, and a pack venting element in the pack housing configured to exhaust venting gases from the pack housing. The sand-filled compartment forms a venting channel filled with sand and is configured to guide venting gases exhausted from the pack venting element through the sand to a venting outlet in the coffin in the event of a thermal runaway of one or more of the battery cells of the battery pack.