Battery Thermal Runaway Prevention via Pressure-Activated Fluid Cooling
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Solution Overview
Problem
Lithium-ion batteries in electric vehicles are prone to thermal runaway events due to battery cell failures, which can lead to uncontrolled temperature increases and destructive fires, posing a significant risk, especially at temperatures above 100° C.
Innovation Solution
The battery cells incorporate a thermal control fluid system with pressure-sensitive valves that automatically open to release thermal control fluid into the core when pressure exceeds a predetermined value, and a secondary valve to vent gases when the fluid's pressure reaches a lower threshold, along with a one-way valve connecting to a remotely located reservoir to supply fluid at reduced pressure, effectively mitigating thermal runaway by cooling and exhausting flammable gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal control fluid is stored in large quantities within each battery cell, then thermal runaway prevention capability is improved, but battery cell size and weight increase
Solution Approach 1:
The invention extracts the thermal control fluid storage function from individual battery cells and relocates it to a centralized reservoir positioned above the battery assembly. This allows the fluid to be stored externally rather than within each cell, reducing individual cell weight while maintaining overall thermal protection capability through the centralized storage system
Solution Approach 2:
The centralized thermal control fluid reservoir serves multiple battery cells simultaneously through a distribution system with multiple outlets. This multi-functional approach allows a single storage location to provide thermal protection for the entire battery assembly, eliminating the need for separate fluid storage in each cell
2Speed
If pressure-sensitive valves are set to open at low pressure thresholds, then thermal runaway response speed is improved, but false activation risk increases
Solution Approach 1:
The invention uses pressure-sensitive valves with specifically calibrated pressure thresholds that open at predetermined pressure levels. This parameter-based control ensures the valves activate only when thermal runaway conditions generate sufficient pressure, preventing false activation from normal operational pressure variations while maintaining rapid response to actual thermal events
Solution Approach 2:
The pressure-sensitive valves provide automatic feedback-based control by monitoring internal pressure conditions and automatically opening when threshold pressure is reached. This feedback mechanism ensures the system responds only to genuine thermal runaway conditions that generate the required pressure, rather than normal operational fluctuations
3Weight of stationary object
If thermal control fluid is stored in a centralized reservoir, then battery cell weight is reduced, but system complexity increases
Solution Approach 1:
The invention merges the thermal control fluid storage function into a single centralized reservoir that serves the entire battery assembly. This consolidation combines multiple storage functions into one location, reducing overall system complexity compared to having separate storage systems in each battery cell while maintaining the ability to protect the entire battery pack
4Device complexity
If gravity-based fluid flow is used, then active pumping components are eliminated, but fluid flow control precision decreases
Solution Approach 1:
The invention uses gravity as the driving force for thermal control fluid flow from the centralized reservoir to the battery cells. This self-service approach eliminates the need for active pumping components, as the fluid naturally flows downward under gravity when pressure-sensitive valves open, providing passive thermal protection without complex mechanical systems
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 solution passively and automatically addresses thermal runaway events by cooling the core and venting gases, reducing the risk of fire and enabling reusability of the battery cells after an event, while minimizing the size and weight of the battery packs through reduced thermal control fluid storage.
Implementation Method 1
a first pressure sensitive valve positioned between the core and the source of thermal control fluid, the first pressure sensitive valve adapted to open when pressure within the core exceeds a first pre-determined value
Implementation Method 2
the source of thermal control fluid is positioned above the core, wherein when the first pressure sensitive valve is opened gravity will cause the thermal control fluid to flow downward into the core
Implementation Method 3
effectively mitigating thermal runaway by cooling and exhausting flammable gases
Implementation Method 4
a second valve to vent gases when the fluid's pressure reaches a lower threshold
Data Source
AI summary
A battery includes a plurality of battery cells, each battery cell including a core, a source of thermal control fluid in fluid communication with the core, and a first pressure sensitive valve positioned between the core and the source of thermal control fluid, the first pressure sensitive valve adapted to open when pressure within the core exceeds a first pre-determined value.