Battery Pack Exhaust Conduit Layout for Thermal Runaway Isolation
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Solution Overview
Problem
Battery packs in electric vehicles face thermal runaway issues due to excessive heat generation, which can lead to cell damage and uncontrollable self-heating, exceeding the cooling capabilities of thermal management systems.
Innovation Solution
A battery pack design featuring a plurality of electrochemical battery cells with vent openings that open in response to elevated pressures, coupled with an elongated exhaust conduit and fins to direct hot gases away from adjacent cells, and a pack vent to exhaust gases to the ambient environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal management system cooling capability is increased, then heat dissipation is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the thermal runaway gas venting function from the main thermal management system by providing dedicated exhaust conduits and pack vents that independently channel hot gases away from battery cells. This separation allows the thermal management system to focus on cooling while thermal runaway protection is handled by the extraction system.
Solution Approach 2:
The exhaust conduits act as intermediary structures that receive hot gases from venting battery cells and transport them to safe discharge locations away from the battery pack. These conduits mediate between the source of thermal runaway and the surrounding environment, preventing direct heat transfer to adjacent cells.
2Speed
If cell vent opening pressure threshold is lowered, then thermal runaway response speed is improved, but risk of premature venting increases
Solution Approach 1:
The patent implements different venting mechanisms at different locations with different pressure thresholds. Cell vents have lower pressure thresholds for rapid response to thermal runaway, while pack vents have higher thresholds and serve as secondary protection. This local differentiation allows optimized response characteristics at each level.
Solution Approach 2:
The venting system is segmented into multiple independent components: individual cell vents on each battery cell and a separate pack vent in the battery pack housing. This segmentation allows each component to operate independently with its own pressure threshold, providing staged protection without requiring a single high-threshold system.
3Object-affected harmful factors
If exhaust conduit length is increased, then hot gas diversion effectiveness is improved, but pressure drop and flow resistance increase
Solution Approach 1:
The exhaust conduits are routed through the battery pack structure in three-dimensional space, utilizing vertical and lateral dimensions to achieve effective hot gas diversion. By routing conduits through available structural spaces rather than following simple linear paths, the system achieves long diversion paths without excessive pressure drop.
Solution Approach 2:
The exhaust conduit system is designed to leverage the high pressure and velocity of gases naturally generated during thermal runaway. The conduit geometry and routing are optimized to minimize flow resistance while maintaining effective diversion, utilizing the inherent pneumatic energy of the venting process rather than requiring additional pumping power.
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 mitigates thermal runaway by directing hot gases and particulate matter away from adjacent battery cells, preventing interaction and potential damage, thus enhancing the safety and performance of battery packs.
Implementation Method 1
The vent cap is configured to open at a predetermined pressure to release hot gasses from the cell cavity into the gas flow channel
Implementation Method 2
The fins are configured to direct the hot gasses along the longitudinal center axis and toward the terminal end and the pack vent
Implementation Method 3
A pack vent disposed at the terminal end opens in a manner similar to that of the above-summarized cell vents to thereby exhaust the gasses to the surrounding ambient environment
Data Source
AI summary
A battery pack includes an elongated exhaust conduit defining a gas flow channel. The exhaust conduit includes a longitudinal center axis and a terminal end having a pack vent. The battery pack also includes fins disposed within the gas flow channel, and a plurality of battery cells arranged adjacent to the exhaust conduit. Each respective battery cell includes an outer casing defining a cell cavity. The casing defines a cell vent opening. An anode and a cathode are disposed within the cell cavity, and a vent cap covers the cell vent opening. The vent cap opens at a predetermined pressure to release hot gasses from the cell cavity into the gas flow channel. The fins direct the hot gasses along the longitudinal center axis and toward the terminal end of the exhaust conduit, and thus to the pack vent for discharge to the surrounding ambient environment.