PCM-Controlled Battery Venting for Thermal Runaway Mitigation
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Solution Overview
Problem
Large battery packs face thermal runaway events due to excessive heat generation from lithium-ion cells and external factors, which can spread to adjacent cells, posing a risk to the entire battery array.
Innovation Solution
A multi-cell rechargeable energy storage system incorporating a phase-change material (PCM) device on a vent system that melts to create crossflow ventilation, combined with a fan and electronic controller, to mitigate thermal runaway by cooling affected battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If battery cells are placed in close proximity to increase energy density, then productivity and energy storage capacity improve, but thermal runaway can spread to adjacent cells increasing safety risks
Solution Approach 1:
The battery enclosure is segmented into multiple compartments or zones using partitions or baffles, which physically separate battery cells or modules. This segmentation prevents thermal runaway from spreading across the entire battery pack while maintaining high energy density through optimized cell arrangement within each compartment.
Solution Approach 2:
Thermal barrier materials or heat-resistant intermediaries are placed between adjacent battery cells or modules. These intermediary layers act as thermal insulation barriers that block heat transfer during thermal runaway events, preventing fire propagation while allowing the battery pack to maintain high cell density for maximum energy storage.
2Temperature
If ventilation is increased to remove heat from battery modules, then temperature control improves, but thermal runaway events can spread more easily through air flow
Solution Approach 1:
Ventilation openings are strategically positioned and sized differently across the battery enclosure based on local thermal requirements. Areas with higher heat generation have enhanced ventilation, while areas prone to fire spread have restricted or filtered ventilation. This localized quality approach optimizes heat removal without creating pathways for thermal runaway propagation.
Solution Approach 2:
Ventilation systems incorporate fire suppressant gases or inert atmospheric conditions in the airflow path. The ventilation openings are designed to introduce or maintain an inert atmosphere (such as nitrogen or carbon dioxide enriched air) that suppresses combustion while still allowing heat removal, thus preventing thermal runaway spread through the ventilation system.
3Object-affected harmful factors
If enclosure is sealed to prevent thermal runaway spread, then safety improves, but heat accumulation occurs leading to increased thermal runaway risk
Solution Approach 1:
The enclosure incorporates porous thermal barrier materials or phase-change materials with controlled porosity. These materials allow passive heat dissipation through conduction and radiation while maintaining physical containment. The porous structure provides thermal insulation properties that block fire spread pathways while enabling heat to escape through conduction to external heat sinks.
Solution Approach 2:
Phase-change materials (PCMs) are integrated into the enclosure structure to absorb excess heat through phase transitions (such as melting or sublimation). These PCMs remain in solid state under normal conditions providing structural integrity and thermal insulation, but transition to liquid or gas phase during thermal events to absorb large amounts of heat energy, preventing both heat accumulation and fire spread.
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 PCM device, in conjunction with ventilation and a fan, effectively cools battery modules and prevents the spread of thermal runaway, ensuring the safety and stability of the battery array.
Implementation Method 1
a phase-change material (PCM) device arranged on the second vent and configured to melt in response to an increase of temperature inside the first enclosure from at least one of the battery modules experiencing a thermal runaway event
Implementation Method 2
the PCM device, in conjunction with ventilation and a fan, effectively cools battery modules and prevents the spread of thermal runaway
Implementation Method 3
the PCM generates crossflow ventilation through the first enclosure to cool the battery modules therein
Data Source
AI summary
A multi-cell rechargeable energy storage system (RESS) includes a plurality of battery cells organized into battery modules and a first enclosure configured to house the battery modules. The RESS also includes a first vent arranged on the first enclosure and configured to direct air from inside the first enclosure to an environment external to the first enclosure. The RESS additionally includes a second vent arranged on the first enclosure and configured to direct air into the first enclosure from the environment external to the first enclosure. The RESS further includes a phase-change material (PCM) device arranged on the second vent and configured to melt in response to at least one of the battery modules experiencing a thermal runaway event. In combination with the first vent, the PCM generates crossflow ventilation through the first enclosure to cool the battery modules therein and mitigate thermal runaway.