Battery Pack Cap Cartridges for Thermal Cascade Suppression
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Solution Overview
Problem
High voltage traction battery packs in electrified vehicles experience thermal events due to venting of battery cells, leading to thermal cascades and potential damage to adjacent cells.
Innovation Solution
A cap and finger assembly in the battery pack supports cartridge assemblies that hold a mixture of agents, including silicon dioxide, aluminum oxide, and sodium silicate, which are released during a thermal event to arrest oxygen, electrically isolate, and reduce temperature, using materials that melt at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If battery cells are allowed to vent during thermal events, then pressure relief is achieved, but thermal cascade to adjacent cells occurs
Solution Approach 1:
A cap assembly with cartridge assemblies is introduced as an intermediary component between venting battery cells and adjacent cells. The cap receives vent byproducts through slots, while cartridge assemblies release agents that suppress thermal propagation, preventing direct thermal contact with adjacent cells.
Solution Approach 2:
The venting process, which normally releases harmful thermal energy and byproducts, is converted into a beneficial process by capturing the vent byproducts in the cap assembly and simultaneously deploying suppressant agents that use the thermal event as a trigger to release protective materials that prevent thermal cascade.
2Reliability
If suppressant agents are deployed during thermal events, then thermal propagation is suppressed, but device complexity increases
Solution Approach 1:
The cartridge assemblies are designed to automatically release suppressant agents in response to thermal events without external control. The thermal event itself triggers the release mechanism, eliminating the need for sensors, controllers, or external actuation systems.
Solution Approach 2:
The cap assembly is segmented into multiple cartridge assemblies, each independently capable of releasing suppressant agents. This modular design allows the system to scale with battery pack size while maintaining manageable complexity through standardized repeating units.
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 suppresses thermal events by reducing oxygen availability, enhancing electrical isolation, and lowering vent gas temperatures, thereby preventing further cell damage.
Implementation Method 1
using materials that melt at elevated temperatures
Data Source
AI summary
The techniques described herein relate to a traction battery pack assembly, including an enclosure assembly that provides an interior area and a cell stack within the interior area. The cell stack includes a plurality of battery cells disposed along a cell stack axis. Each battery cell includes at least one terminal tab that projects outward from the cell stack axis. Further included is a cap and a plurality of fingers projecting from the cap. Each of the fingers is spaced-apart from one another to provide at least one slot that receives a portion of the at least one terminal tab. Each of the plurality of fingers is provided by a cartridge assembly. Each of the cartridge assemblies holds agents and is configured to release the agents in response to a thermal event proximate the respective cartridge assembly.