Gas Venting Techniques in EV Battery During Thermal Runaway

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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Thermal management system for electric vehicle battery packs that helps prevent thermal runaway in adjacent battery cells from spreading. The system uses separate exhaust manifolds for each set of battery compartments instead of a single exhaust. This prevents hot gases vented from a failing cell in one set from flowing over other cells in a neighboring set. It also allows selective heating or cooling of air delivered to the compartments based on their temperatures.

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End cover assembly for energy storage devices like batteries that improves explosion threshold accuracy of the pressure relief valve. The assembly has a top cover, explosion-proof valve, and protective sheet. The top cover has a recessed mounting surface with a vented hole and an explosion-proof hole. The explosion-proof valve covers the explosion hole on the second mounting surface. The protective sheet covers the explosion hole on the bottom of the recess. This configuration allows air pressure to equalize between the explosion-proof valve and protective sheet.

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Battery pack with an integrated fire suppression system to mitigate the risk of secondary ignition or explosion in large battery packs. The system uses fire extinguishing valves inside the battery modules that open when heated to release an extinguishing agent. This allows immediate and localized suppression if a module experiences thermal runaway or fire. The valves deform internally due to heat to open the output hole. They are located in the middle of the gas passage and inserted into the module sidewall. This ensures the extinguishing agent is dispersed throughout the module to prevent propagation. The valves operate independently of the battery management system.

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Battery pack design to prevent thermal runaway in one cell from affecting other cells. The battery pack has a first box body with battery cells inside. Each cell has an explosion-proof valve. In the pack design, there are side plates separating adjacent cells. Between the side plates is a protective plate. When a cell bursts its valve during thermal runaway, the protective plate prevents the released heat and gas from breaking through the side plate and directly impacting the opposite cell's valve. The protective plate guides the heat and gas to the bottom of the pack instead. This prevents chain reactions between cells.

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A battery module pressure relief system that safely vents internal pressures during cell failures to prevent explosions. The system uses a gas-impermeable pressure release vent that ruptures at high pressures. It also has a gas-permeable pressure relief valve. The module housing and cover seal the cells. A plate above the cells guides gases to the vent. The vent has thicker and thinner sections. The thicker section fails at high pressures while the thinner section stays intact. This allows the vent to rupture selectively to relieve pressure without fully breaching the housing seal.

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Battery vent design and manufacturing method that improves safety by enhancing vent fracture reliability and controlling vent pressure release threshold. The vent has a notch with a two-step depth profile. A first notch without intersection is made initially at a certain depth. Then a second notch with shallower depth is added on part of the first notch. This two-step notch design prevents intersection points and stress concentration that can weaken the vent. It also allows deeper notch depths to be achieved in a single stamping step versus multiple stamps. This improves vent reliability and consistency in fracturing at a desired internal pressure.

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Gas evolution in lithium-ion batteries represents a pivotal yet underaddressed concern, significantly compromising long-term cyclability and safety through complex interfacial dynamics material degradation across both normal operation extreme thermal scenarios. While extensive research has focused on isolated gas generation mechanisms specific components, critical knowledge gaps persist understanding cross-component interactions the cascading failure pathways it induced. This review systematically decouples at cathodes (e.g., lattice oxygen-driven CO2/CO high-nickel layered oxides), anodes stress-triggered solvent reduction silicon composites), electrolytes (solvent decomposition), auxiliary materials (binder/separator degradation), while uniquely establishing their synergistic impacts battery stability. Distinct from prior modular analyses, we emphasize that: (1) emerging systems exhibit fundamentally different thermodynamics compared to conventional materials, exemplified by sulfide solid releasing H2S/SO2 via unique anionic redox pathways; (2) crosstalk between components creates ... Read More

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Battery pack for vehicles with a fluid-filled compartment in the battery holder to improve cooling and prevent uneven temperature distribution. The holder has a base plate with through openings for venting battery cell gases. It also has a closed compartment partially filled with fluid. The fluid spreads heat generated by the cells, reducing risks of hot spots. The compartment can extend across the base plate. Grooves channel gas to the compartment. The compartment surface structures facilitate heat transfer. The fluid can be a phase change material for temperature regulation.

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A battery pack with a venting system that prevents case deformation during cell venting. The pack has a case with a bottom cover, fastened together at multiple points. The main body has a recess facing the cover. A second space forms between the recess and cover. The pack has an opening between the first and second fastening points, connecting the second space to the outside. This allows gas to vent out during cell overcharge without bulging the case. The main body is cast for simplicity.

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Battery arrays for traction battery packs with staggered venting paths to release vent byproducts during thermal events. The battery arrays have an interior venting channel in a component like a cell sensing assembly and an exterior venting hole through the pack cover. The hole is staggered relative to the channel to create a tortuous venting path between the battery interior and exterior. This reduces venting speed and limits ingress of vent byproducts from neighboring packs.

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