Gas Venting Techniques in EV Battery During Thermal Runaway

This study advances anode-free lithium-metal batteries (AFLMBs) by integrating nickel-rich NMC90 cathodes and fluorine-rich electrolytes in large-format 18650 cylindrical cells. A key innovation is the incorporation of 10 wt % Li-rich Li2NiO2 as a prelithiation agent cathode, which mitigates initial lithium-loss improves Coulombic efficiency. The electrolyte includes 30% (v/v) fluoroethylene carbonate (FEC) cosolvent, suppresses inactive lithium deposition stabilizes solid interphase (SEI). Unlike conventional AFLMBs that require external pressure, this work uses stainless-steel casing with tailored jelly roll configuration to mechanically regulate plating. optimized cells deliver an energy density 320 Wh/kg, maintain stable cycling over 140 cycles, support 4C-rate operation. Post-mortem analysis reveals LiF-rich SEI extends cycle life, while operando X-ray diffraction provides insights into structural evolution. research offers scalable strategy for high-energy through synergy prelithiation, design, mechanical stabilization.

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The performance of lithium metal batteries is significantly affected by temperature variations, which makes it challenging for them to operate across a wide range. Herein, widetemperature adaption electrolyte proposed, enabling excellent electrochemical from 40 C 60 C. Large, 5.8 Ah pouch cells employing such an achieve high energy density 503.3 Wh kg1 at 25 with lifespan 260 cycles and outstanding 339 critical role the solid interphase (SEI) in determining temperaturedependent unveiled. It demonstrated that LiFrich, anionderived SEI facilitates Li+ diffusion SEI. Moreover, accelerated desolvation observed. These two aspects promote kinetics anodes further inhibit dendrite growth low temperatures. This work showcases importance understating chemistry enable batteries.

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Battery box design to enable directional exhaust of gas from a pressure relief valve when installed in an enclosed electrical appariment like an electric vehicle. The battery box has an auxiliary member that encloses an exhaust channel with an external port. The pressure relief valve mounts through the channel exit. This allows gas expelled by the valve to flow through the channel and out the auxiliary member port instead of inside the battery box. This directs the exhaust to the vehicle's existing air outlet, preventing backpressure buildup in the battery compartment.

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Battery module design to prevent thermal runaway propagation in electric vehicles. The module has a cell cover member that discharges gases generated by a venting battery cell to the outside of the module. This prevents the gases from spreading to adjacent cells and causing thermal runaway propagation. The cover separates from the cell body under gas pressure to form a venting path.

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Battery module housing with directed and controlled venting for lithium-ion battery packs in electric vehicles. The housing has two types of vents: burst vents to rapidly release excess gas buildup during cell operation, and selective permeability vents to slowly allow gas exchange between the cell stack and housing cavity. This enables directed venting of excess gases away from the vehicle cabin while still allowing controlled breathing of the cells. The burst vents open at high pressure thresholds, while the selective permeability vents have membranes that allow gas exchange but not moisture.

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Battery pack design to safely discharge high-temperature gases from a battery cell's vent without releasing them to the outside. The pack has an exhaust duct inside the case that connects to the cell's vent. When the cell vent opens, the gas goes into the duct instead of the case. This allows the gas to cool and disperse internally before being released to the outside through the duct. Features like thin ducts, intersecting duct paths, and blocking labels on the duct outlet further attenuate the gas energy.

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Battery module and rack design to suppress fires in battery packs and prevent propagation when thermal runaway occurs. The module has a valve nozzle to feed firewater into the module if vent gas or flames are detected. An expandable member inside the module absorbs fluid to block air inlets and outlets when the valve opens. This keeps the water level high to cool cells. The rack has a water tank, pipes, and sensors to feed water into modules if runaway is detected.

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Battery module with improved safety to prevent ignition propagation between modules in a battery pack. The module has venting holes in the frame, an end plate, and an anti-inflammatory cover over the venting holes. If a cell ignites, the cover quickly releases gas and prevents scatter of burning debris into adjacent modules. It also prevents external fire from entering the module through the vent holes. This isolates ignition to contain damage within the module and prevents chain reactions.

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Secondary battery with improved safety by inducing gas discharge in a specific direction. The battery has a case with an accommodation portion for the electrode assembly and a sealing portion. An extension on the sealing portion contains a vent member with a lower melting point resin. This allows the sealing strength to decrease at high temperatures, facilitating venting of gas when the battery overheats without damaging the electrode lead. The vent member is spaced from the lead film in the sealing portion to minimize gas release there, but overlaps/contacts the lead film in the accommodation portion.

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Battery pack module for electric aircraft that mitigates the risk of thermal runaway propagation and explosion in the battery pack. The module has a flexible enclosure with a pressure vent mechanism that allows controlled release of gases during thermal runaway instead of a rigid enclosure that can withstand high pressures. This reduces weight and improves power density. The vent mechanism prevents explosion by evacuating gases without fracturing the enclosure. It also reduces temperature propagation between cells by venting gases instead of containing them. This controlled venting mitigates the risk of explosion and propagation compared to a rigid enclosure that aims to contain gases.

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Secondary battery with integrated safety vent mechanism that enables repeated use of the battery's venting system. The battery features a case with an open side and a cap plate with a vent hole. A safety vent is positioned on the cap plate, comprising multiple layers that can be magnetically controlled to seal or open the vent. This design allows the battery to be charged and discharged multiple times while maintaining its venting capabilities. The safety vent's magnetic biasing system enables precise control over venting behavior, ensuring safe operation even after multiple charge cycles.

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Battery cell arrangement with a gas guiding device that prevents hot gas from escaping during thermal runaway events. The cell features a housing with a degassing opening that can be sealed by a flap-like mechanism. The degassing opening is connected to a gas outlet by a spring-loaded flap that seals when the cell reaches a predetermined pressure threshold. The flap can be disengaged to allow gas release while maintaining cell integrity. This design provides a one-sided barrier against gas escape while maintaining cell integrity.

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Battery module and pack design to improve safety by efficiently dissipating heat and smoke during cell runaway. The module has a compact enclosure with channels and holes to route smoke and heat out. The top cover has holes for smoke venting. The sidewalls have channels to guide smoke to end plates with holes for further venting. This allows smoke to escape quickly from the enclosure when a cell runs away, preventing spread to other cells. The enclosure geometry and venting configuration allows effective smoke and heat dissipation in compact modules with limited lateral and vertical space.

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Battery cell design with improved safety by allowing venting of internal gas at elevated temperatures. The cell has an electrode assembly with a protruding tab. The packaging bag sealing around the tab has a weak zone that separates at high temperatures, releasing internal gases. This prevents pressure buildup and thermal runaway. The weak zone is formed by fusion of the sealing adhesive with the bag. The adhesive thickness exceeds 25 microns and has lower tension versus the tab or bag in certain temperature ranges to enable separation.

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Battery arrays for traction battery packs that have improved thermal management and venting to mitigate thermal propagation between cells during battery failures. The arrays have separate cell banks with thermal barriers and dedicated venting paths between them. This prevents thermal runaway in one cell from spreading to adjacent cells. The barriers prevent direct cell-to-cell contact while the venting allows isolated expulsion of gases during cell failures.

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A balance explosion-proof valve for power batteries with simplified design and reduced manufacturing costs compared to prior art designs. The valve has a pressure relief assembly on the upper side and an air pressure balance assembly on the lower side. The pressure relief assembly has a piston, membrane, and cover plate. The air pressure balance assembly has a guide rod, lower cover, and balance valve. The valve body has an outer ring, inner ring, and connecting arms with pressure relief holes. The piston seals against the outer ring. The lower cover has an outer protrusion that contacts the inner ring. A spring supports the guide rod between the rings. The membrane covers the piston cavity and vent grooves in the cover plate allow pressure equalization.

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End cover assembly for energy storage devices like batteries that improves explosion valve accuracy by reducing air pressure gaps between the valve and protective sheet. The end cover has a top cover with recessed areas for the explosion valve and a vent. The explosion valve covers the valve hole in the top cover and the protective sheet covers the vent recess. This configuration allows the explosion valve to function properly with normal pressure instead of higher pressure from the gap between the valve and sheet.

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Pouch type secondary battery with an expandable gas collection space to prevent venting or delay venting during overcharge or short circuit. The battery has a pouch case with a curved tab welding surface that stretches during expansion to maximize gas collection. The case is molded with this shape instead of being fully sealed around the tabs. The curved surface allows gas expansion without rupturing the case. This prevents venting or delays venting compared to fully sealed cases. The molded curved surface maintains shape during expansion to collect gas.

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Battery module design to prevent chain reactions and explosions in battery packs. The module has a heat sink with rupture parts and a sealing material layer. When a battery cell overheats and pressurizes, the rupture parts break allowing sealing material to vent out. This prevents high-temperature gas from spreading to adjacent cells and starting chain reactions.

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Electrical storage module for high voltage electric vehicles that has a degassing line to improve safety when exhaust gases escape. The module contains electrochemical cells to store electrical energy. If there's a cell defect or short circuit, it can lead to thermal reactions and pressure buildup. To prevent hot gases escaping, the module has a degassing valve and opening. But the module also has a separate degassing line that leads exhaust gases away from the main housing. This isolates hot gases from the module interior, preventing them from entering the vehicle cabin.

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